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Node JS Full Course 2026 | Complete Backend Development Course | 17 Hours — Transcript

by Sangam Mukherjee · 195,134 words · 26,574 segments · language en · Watch on YouTube

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0:00Hey everyone, welcome back. So in this
0:01particular video, you're going to learn
0:03each and everything that you need to
0:04know to start your journey with NodeJS.
0:06And this is a open challenge to each and
0:08every one of you. Just watch this
0:10complete video and then show me a better
0:12course than this one on YouTube even in
0:15the paid courses. Okay. So let's see
0:17what are the things we're going to
0:18cover. So first of all, I wanted to
0:19mention the very key point and that is
0:21this complete course is built on
0:22posgress and this is not a MongoDB
0:25course that you usually find on other
0:27YouTube videos. Okay. second. So let's
0:29see all the sections because this is
0:30very very important. Uh you need to know
0:32that what are the things we going we are
0:34covering and in which order. Okay.
0:36Before that uh wanted to mention one
0:38more point and that is this particular
0:40video took me more than 2 months to
0:41create. So please like this video,
0:44comment and also if possible please
0:46share with your friends and this will be
0:47very much helpful because this will help
0:49my channel to grow and it will also help
0:52to complete 100k as soon as possible. So
0:54first of all you can see that this is
0:56actually divided into 11 section. So we
0:58are going to start with setup. So first
1:00we will understand how you can install
1:02NodeJS runtime basics, npm package.json
1:05and scripts, TypeScript configuration
1:08and process object. Then we'll move to
1:10our next module which is very very
1:12important. We are going to understand
1:13all the code modules. So we are going to
1:15understand crypto module, OS module,
1:17path module. Then we are going to
1:19understand timers asynchronous flow file
1:22system APIs, buffers, URL module, event
1:25emitter and we are going to end this
1:27particular module with streams. Then we
1:30have a dedicated section on HTTP module.
1:32So here we are going to understand
1:34native HTTP module without express. Here
1:37we are going to cover native HTTP
1:39server, manual routing, reading request
1:41bodies, JSON responses and external API
1:45implementation. Then we are going to
1:46have a little more advanced uh section
1:49we are going we are going to understand
1:50NodeJS internals. So NodeJS runtime
1:52internals V8 engine live blocking versus
1:56non-blocking and cluster module. Okay.
1:59Then we have a complete dedicated
2:01section on postgress. Now this is a
2:03mandatory section. This you need to
2:05complete before we are going to uh start
2:07working on the CRUD. So here you're
2:08going to understand database, schema,
2:10tables, data types, constants, keys, uh
2:14complete SQL, CRUD, relationships, join,
2:17aggregations and indexes and
2:18transactions. Okay. Then we are going to
2:20have our main master project that we are
2:23going to build and this will be huge
2:24project. You're going to understand a
2:26lot of things. So first the first module
2:28will be to understand how you can create
2:30a proper express project, proper folder
2:33structure. So you can see that we are
2:34going to have our application setup with
2:36express poller. We are going to use
2:38scalable folder structure routes health
2:41checks server life cycle docker compost
2:43posgress setup custom database migration
2:46because we are not using any third party
2:48packages and centralized error handling.
2:50Then we are going to have our o and JWT.
2:53So we're going to have user registration
2:54flow login JWT generation authentication
2:57middleware admin middleware and we are
2:59also going to implement Google O login.
3:02Then we'll move to our CRUD and admin
3:04API. So we're going to have our normal
3:05crap because this is actually mandatory.
3:07So we are going to create user task,
3:09fetch, update, delete and then admin
3:11operations. Then moving to next one,
3:13we're going to have a complete dedicated
3:14section on file upload and we're going
3:16to use cloudinary. So with this we're
3:18also going to use mult. So this will be
3:20how you can handle multipart upload
3:22flow, multiple middleware, cloudinary
3:24upload helper, banner creation and fetch
3:27APIs. Then we're going to move to our
3:28radius section. So in this particular
3:30section we're going to cover radius. So
3:32this is also a mandatory section. So
3:33here you're going to understand all the
3:35radius concept how you can create radius
3:37client cash asset pattern still cast
3:39invalidation rate limiting and popsup
3:41concept and then we'll move to our next
3:43section which will be how we are going
3:45to integrate radius and bool mq and you
3:47can implement background jobs for this
3:48one we're going to implement this one in
3:50our previous project only so we're going
3:51to understand how you can create cues
3:53jobs workers blemq project setup
3:55cloudinary deletion in the background
3:57and also how you can implement a
3:59reliable asynchronous architecture so
4:01all those things we are going to cover
4:02in this whole module. All right. So
4:04before we'll start so two very important
4:06points I wanted to mention. The first
4:07one is that I finally created the
4:09official LinkedIn page for age debop. So
4:12I highly request everyone to follow this
4:13particular page and help me to reach at
4:16least 5,000 followers as soon as
4:18possible because some of you already
4:19know that I'm not that much active on
4:21social media and don't promote all these
4:23videos and everything. But because my
4:24channel is almost close to 100K so I
4:27thought this will be right time to start
4:29the page. So I think I need help from
4:31all of you. So I've added the link in
4:32the description. Second, uh I think some
4:35of you already know that I have a
4:36upcoming course on my debub which is my
4:39uh website and you can see that almost
4:415,000 people already joined the weight
4:42list. So in case you are interested,
4:44please uh join this course. I added the
4:47link in the description also. Third
4:49thing uh to get the source code of this
4:51enter nodejs uh course what you can do
4:53right I've added the link in the
4:56description that is also completely
4:58free. So you can just go to the project
4:59section and you will be able to download
5:01the source code for free. So with this
5:03now let's get started and good luck.
5:06Okay. So now let's get started. So this
5:08will be a very long video. I think I
5:10already explained and also by the length
5:12of this video you can understand. So
5:14what I'll suggest right so a couple of
5:15things I wanted to mention. Uh so first
5:17one is I think a lot of people already
5:19asked me that I already have multiple
5:21NodeJS uh videos that uh after watching
5:25those videos do I still need to watch
5:27this particular video? See this answer
5:29is little tricky the why I'm telling
5:31this because I already uploaded one
5:34video that doesn't mean that in this
5:36particular video I'm going to discover
5:37some new things and I'm going to explain
5:39you are getting at the end of the video
5:41you'll see that we are going to
5:43understand the almost similar concept
5:45that I already covered in the previous
5:46video but then what is the difference
5:49okay the difference will be first of all
5:51in this particular video some of the
5:53concept and some of most of the
5:55explanation will be much much much more
5:57detailed Okay. And you'll understand
5:59this one very very clearly once I start
6:01this particular video. Second, this
6:04video we are going to use posgress,
6:06right? I already mentioned in the
6:07previous video and almost all videos
6:09that are available on YouTube, we'll see
6:10that most of the videos are built on
6:12MongoDB, right? Uh because it's easy to
6:15record and most of the uh student want
6:17to learn MongoDB also because M was very
6:20popular. I think it's still very popular
6:22but now nowadays everyone wants to learn
6:24posgress. So that is the main change in
6:26this particular video. So there will be
6:28one dedicated section where you are
6:30going to understand poseless also. So
6:31I'm going to add some video that I
6:33already created very recently. So it
6:36will be around 4 hours. So that I will
6:38be adding in middle so that before we
6:40are going to start the project. So you
6:42will see that there will be a postgress
6:43section. Third, there are some core
6:46modules we are going to understand much
6:47detail way. Okay. And this is very very
6:49important. So once I start you'll
6:51understand what I'm talking about.
6:53Fourth one the main project that we are
6:55going to build that will be much more
6:57detailed. Now in the previous part one
6:59video whatever I covered so it was like
7:01a normal CR. Now here also we are going
7:03to cover normal CRUD but there will be
7:05some more advanced topic we are going to
7:07understand. For example how you can work
7:08with radius how you can implement
7:10background job. Now the main question
7:13comes to this that if I already watch
7:15this video or if I already know NodeJS
7:18can I still watch this video? The answer
7:20is absolutely yes. Okay. So you can
7:22watch this video. This video is going to
7:24give you fantastic idea about NodeJS.
7:26How you can work, how you can create
7:28proper folder structure and it will give
7:30you complete overview. Okay. So you
7:32don't have to watch multiple videos.
7:33Second when I'm going to upload the part
7:35two of NodeJS which will be NodeJS
7:38microservices with Postgress and Kafka,
7:40you'll see that it will be much more
7:41easier for you to understand. So I hope
7:43that this will answer some of the query.
7:45Now with that let's get started. The
7:47first of all you can see that I have a
7:49blank folder. We are going to use VS
7:51code for this and we will take some
7:52things uh most of the things very very
7:54slowly but there are some prerequisite
7:56that you need to know. So first
7:57prerequisite will be you should know
8:00JavaScript ES6 that is mandatory. We are
8:03not going to cover JavaScript ES6 or
8:05very very basic concepts because I
8:07already uh I thought that okay you know
8:09this okay I will consider this you
8:11already know this concept and then you
8:13are watching this video. If you haven't
8:15know all of this there is no point to
8:16watch this video. So first you you have
8:18to watch or learn JavaScript ES6
8:20concept. Second TypeScript basics you
8:24need to know okay because this video
8:26actually will be built completely on
8:27TypeScript. So I already have a
8:28TypeScript video also. So with that now
8:31what we going to do right? So how this
8:33first section will be [snorts] covered.
8:35So this will be our first section. You
8:36can see that I created NodeJS basics and
8:39uh core modules we are going to cover.
8:41So Node basics and NodeJS code modules.
8:44So now first what you have to do right?
8:46So let's go here and just search for
8:48NodeJS and then you have to download
8:50NodeJS. Now here one thing you have to
8:52understand. So first of all before we we
8:55will understand that okay what actually
8:56you need to download. First you have to
8:58understand what actually NodeJS is.
9:00Okay. So let's do one thing I'm going to
9:02create one file here and I'm just going
9:04to give this one file name as concepts
9:07MD and this is how we are going to do.
9:09So first let's understand some of the
9:11very very key point and this is going to
9:13help you while giving interview also. So
9:15first of all, NodeJS is
9:18so I'm just going to give like this uh
9:20let's give it like this. So I'll do
9:22NodeJS is JavaScript or JS runtime.
9:28So what I mean by this? So first of all
9:29you have to understand what actually
9:30runtime this particular word means. So
9:33this runtime means that it's actually an
9:35environment where you are actually
9:37running some code. Okay. So runtime is
9:39the environment where you run some code.
9:42Now in the browser what happen right
9:44where JavaScript runs in JavaScript
9:47runs inside your Chrome Firefox suffer
9:50you all these browsers but in NodeJS
9:52your JavaScript runs where on your
9:54computer or maybe let's say you're
9:56running NodeJS on a server. So that
9:58means in NodeJS your JS runs outside
10:03of the browser. Now this is the first
10:05three thing you have to understand.
10:07Okay, this is very very very important.
10:09Okay. And this single line whatever I
10:11have added here. This is the main
10:12foundation of your backend development.
10:14Whatever you are going to do with
10:16JavaScript. So that means NodeJS is JS
10:19runtime. Runtime means we are running
10:21some code and this code we are not
10:24running inside the browser. We are
10:25running outside the browser. And this
10:27can be let's say you are running on your
10:29computer or on a server. I hope this is
10:32clear right. So first of all this is the
10:34first thing you have to understand what
10:35actually NodeJS uses. So NodeJS uses
10:37something called V8. Now what actually
10:40this V8 now this V8 is the same JS
10:43engine that Google Chrome also uses.
10:47Okay. So what actually this is going to
10:49do right? So this is going to take take
10:51your JavaScript code and it's going to
10:53run on your machine. Okay. Now one thing
10:56I wanted to mention that when you're
10:58learning NodeJS as a developer you don't
11:00have to go into depth of learning V8.
11:02There is no I'm not saying no point but
11:04you don't have to do that. You just have
11:06to understand this particular point that
11:08NodeJS is not a new language. Okay. It
11:10is actually JavaScript. We are running
11:12JavaScript only. But this NodeJS has
11:15some extra server side capabilities. So
11:17that NodeJS we can run inside a browser
11:20not inside a browser. Again NodeJS we
11:23are running outside the browser. So this
11:26is one very very important point I
11:27wanted to mention. So first of all what
11:29we are going to do right. So let's go
11:30here and first you have to understand
11:32one very important point and that is
11:34that which version we have to uh sorry
11:36we have to install and you'll see that
11:38here you are going to see something
11:40called LTS now what actually this LTS
11:43means this one this LTS now this LTS
11:46means long-term support now let's say if
11:48you're a student or let's say in college
11:50or maybe let's say I will consider like
11:52less than 3 years of experience right so
11:54you are completely like I'll say in
11:56beginner phase so what you should do
11:58right you should start with this LTS
12:00version. So what this means nothing very
12:03very simple. So LTS means this is a
12:06NodeJS release version and this is a
12:08stable version. Okay means what will
12:11happen? Let's say there are some bug
12:13reported right. So what will happen
12:14right? So they are going to fix that
12:16particular bug as soon as possible
12:18because lot of developers uses NodeJS
12:20worldwide. So this is uh we called as
12:23long-term support version. So this is as
12:26LTS. So what you have to do right
12:28whatever you are using okay let's say
12:30you're using Windows you using Linux or
12:32something else try to download the
12:35latest version of the NodeJS and latest
12:38version in the sense I'm talking about
12:39the LTS version of the NodeJS you don't
12:41have to do anything just have to install
12:43this and once this is done you'll see
12:45that NodeJS will be installed now here
12:47you will see something as npm so what
12:50actually this npm is now npm is actually
12:52the node package managers node package
12:55manager so Here I'm just going to do so
12:58your npm is node package manager. So
13:04what this is going to do? So this is
13:06going to help you to install various
13:08packages. It's going to help you to run
13:10your project scripts. So we are going to
13:12have some scripts you'll understand and
13:14also the most important part it will
13:16help you to manage your dependencies
13:18using package.json. So we have something
13:20called as package.json file. Okay. So
13:23this is why we need this npm. Now you'll
13:27see that once you do that okay so just
13:29download it and install it's very very
13:31simple once you'll do that you go to
13:33terminal and or maybe you can directly
13:35check from here. So what you have to do
13:37right you are going to do node version
13:39v. So this v basically we wanted to
13:42understand what is the version of node
13:43that we are running in this particular
13:45machine and if I enter you see that you
13:47are going to have this 24.14.0 you this
13:51is actually not the LTS version but it's
13:53fine if you want you can directly
13:55download this version from here also
13:57okay so this is the first thing I wanted
13:59to mention so now next thing will be
14:01what we going to do right here also
14:04let's do one thing okay I wanted to show
14:06you the npm version also so if you do
14:08npm version B you are also going to get
14:10the npm version here so now first what
14:13we have to do right so first you see
14:15that we don't have anything here right
14:16so we don't know what file we have to
14:17create what folder structure you should
14:19normally
14:20create while creating any products and
14:22levelable NodeJS application. But before
14:23that what we have to do right we have to
14:24understand some of the concept but
14:26before doing that first let's do one
14:28thing let's create our package dojson
14:30file. So what actually this package
14:32dojson file means because this is where
14:34we are going to start and learning each
14:36and everything. So here what I'm going
14:37to do right because I already mentioned
14:39that npm is your node package manager
14:41which help you to run your uh scripts.
14:44It's going to help you to create your
14:45NodeJS project. It is going to help you
14:48to install packages. Basically it is
14:50going to help you to manage your
14:51project. something like that. So here
14:53what I'm going to do right I am going to
14:54create a new node project. Okay, new
14:57node project. So how I'm going to do
14:59that? So I'm going to do npm in it. So
15:01init means we going to initialize
15:03something and I'm just going to give
15:04minus y. Okay, hyphen y. So here what
15:07I'm going to do right if I do enter so
15:10this is going to create a package.json
15:12on your root. Okay, root means whatever
15:15folder that you have created on the root
15:17you are going to get this particular
15:18file. Now this is one of the most
15:20important file you have to understand
15:21here. Okay, that what actually this file
15:23is doing. But before that what I'm going
15:25to do right I'm going to install some
15:28dependencies and uh and dev
15:30dependencies. So I'm pretty sure if you
15:32don't know the terms so I'm going to
15:33explain what actually that is. So what
15:35dependency I'm going to create and why
15:37we need those dependency because
15:39whenever we are going to create any
15:41project right so we need some packages
15:43or some out ofthebox things that we
15:45don't want to write. So those out
15:47ofthe-box things or features will be
15:49provided by those packages. Right. So
15:51what I'll do right for now because we
15:52are going to use Typescript. So I'm
15:54going to install TypeScript here. Okay.
15:56And here what I'm going to do right. So
15:58first of all or maybe let's do one
16:00thing. Maybe I'm doing or teaching in a
16:02different maybe wrong way. First let's
16:04understand what actually this package
16:05do.json is and then I'm going to create
16:07it. It will be easier. [snorts] So first
16:09you'll see that you are getting quite a
16:10few things. Okay. First you have to
16:12understand what actually each and every
16:14property is. So name name is your
16:16project identifier. Okay, this is your
16:18project identifier. Version is your
16:20current release version. So this is your
16:22project release version. Description
16:24whatever description you wanted to give.
16:26I think I don't have to explain here.
16:28Then you have the important part you
16:30have to understand here you have the
16:32type. So type here is common JS. Okay.
16:34So this is your module system hint. Then
16:37we have very very important part which
16:39is script. Now this script is going to
16:42help you to do something. Now I'm not
16:44going to explain what actually we are
16:46going to do because these when we are
16:47going to implement a project and run the
16:49script you'll understand. Now when I'm
16:51talking about it's going to help you to
16:52do something means here you can create
16:54various script. For example let's say I
16:56wanted to run some test. So I can keep a
16:58test script. I wanted to run my local
17:01server. I'm going to create a script
17:02which is going to help me to run the
17:04local server. I'm going to build
17:06something. I can add a build script.
17:09You're getting right. I wanted to start
17:11this particular project. So I can add a
17:13start script something like this. Okay.
17:16Now why actually we need this particular
17:18package dojson file. Now simply you have
17:19to understand that this particular file
17:23I usually call this one as identity
17:25card. So that mean this particular file
17:26is going to tell me that what actually
17:28this project is and what dependencies
17:31this project is holding or what
17:33dependencies this particular project is
17:35using. Now let's see if I currently do
17:38this. I have five developers that we are
17:41working in a team. Now the second
17:44developer recently joined your team and
17:46then you wanted to that particular
17:48developer want to understand okay what
17:49all things you are using in this
17:50particular project. If you share this
17:52particular file right package.json so
17:54this developer will understand okay
17:56these all script I have this is my main
17:59main entry file. Okay this is my root
18:01file that you are going to understand
18:03later and okay I have these
18:04dependencies. Okay, that mean these
18:06dependencies we are using and I also
18:08have these dev dependencies. Now here we
18:10are going to understand what actually
18:11dependencies versus dev dependencies but
18:14before that you need to understand that
18:15this project is nothing but holding the
18:17information that okay what actually this
18:20project is doing as simple as that. So
18:22now what I'm going to do right first I
18:24am going to install some of the uh
18:26dependencies that we need. So first I
18:28need what because we are using
18:29typescript we need typescript what
18:31actually typescript is going to do. So
18:33here I'm just going to do npm and I'll
18:35do install and I'll do hyphen d. You'll
18:37understand what actually you're doing.
18:38So you're installing a dev dependency.
18:40Here I'm just going to first install
18:41typescript. What typescript is going to
18:43do? This is going to compile your
18:44typescript to your javascript. Then we
18:47have something called tsx. Very very
18:49important. Why? When we're going to run
18:51typescript, what this particular package
18:53is going to do? This is going to run
18:54your typescript directly whenever you
18:57are going to do the development. Okay?
18:59You don't have to create any manual
19:00build setup for this. And for this we
19:03also need a types and we need the node
19:06types. So because we are using
19:08typescript so we need to do what we need
19:10to give type definition right and this
19:12is what we are going to use for that. So
19:14we need three packages typescript tsx
19:17and types/ node. So this is the first
19:20thing we are going to do. I will install
19:22this and we'll see that what will happen
19:24the moment we are going to install there
19:25will be a node modules will be created
19:27and these node modules is going to hold
19:29all this information just now we have
19:31installed. Okay. So this node modules is
19:33going to have all this. You see that we
19:34have typescript tsx types. Now you don't
19:37have to focus or you don't have to
19:38change anything inside of this. Okay. Do
19:40not do anything until unless you're
19:42creating your own common package. Let's
19:44say you're creating your own custom
19:45package and you wanted to check
19:47something. Right? Normally you should
19:49not change anything inside the node
19:51modules. Okay. So you don't have to do
19:52anything here. You'll see that based on
19:54whatever packages we are doing or
19:56installing it will create those folders
19:58or dependencies and the subd
20:00dependencies. So you can see that you
20:01have the subfolder also inside this. So
20:04this is the first thing that we have to
20:06do. Now what I will do right now let's
20:08say I wanted to add some particular
20:12file here. Okay. Okay. This is the uh
20:14script I wanted to add. Okay. Now before
20:16doing that also you have to understand
20:18one thing that currently we don't have
20:19any particular file file in the sense
20:21let's say whenever we are going to write
20:22some code we need to write code right.
20:24So in that case we need to have some
20:26entry file. That means whenever I'm
20:28going to run this particular project,
20:30TypeScript will understand okay this
20:32particular file code I need to see or I
20:35need to watch and based on that I need
20:36to run that. So that means we need to
20:39create some file. But before that also
20:41we need to understand one very important
20:42concept which is if you're a beginner
20:44this can be a very important interview
20:46question also that what actually
20:47dependencies and what is the dev
20:50dependencies extremely important
20:52interview question. I myself got this
20:54question so many times. So to uh explain
20:58in a simpler way dependencies will be
21:01dependencies are something is needed
21:04when the app is running. Dev
21:06dependencies is something needed only
21:10when we are developing or we are
21:12building. So let's put in this way. So
21:14I'll do dependencies
21:16or something needed when the app is
21:21running and dev dependencies will be
21:30something needed when or while
21:33developing
21:36or building. Okay. Now here you have to
21:41understand a couple of things. Okay.
21:42These are very important. So you have
21:44dependencies. Dependencies are something
21:45like runtime package. Extremely
21:48important concept. Okay. You have to
21:50understand all of these because if you
21:51really wanted to learn NodeJS and
21:53everything, you need to know in details
21:55so that you don't depend on AI tools all
21:58the time because as a developer you
21:59should know all these basic things and
22:01you are going to believe me or not. Some
22:04people also lost inter not lost some
22:07people also failed interview by not
22:09answering these basic questions also. So
22:11when we are talking about dependencies
22:12what actually dependencies are right so
22:14you have we call this one as runtime
22:16packages right so whenever you're going
22:19to write some code right you're going to
22:20import something okay or maybe let's say
22:23the your code whatever you're writing it
22:25imports and those particular packages we
22:27uses while serving request or we are
22:30doing something real work for example
22:32let's say there is a HTTP framework that
22:35your serverts file imports whenever your
22:38code will start now this will be your
22:41runtime packages means you are running
22:43some actual code development packages
22:46will be your dev dependencies means
22:47something you use to write compile or
22:50check your code okay not something that
22:54you need when you are going to run that
22:56particular code in production very very
22:58important okay so I'm going to repeat
23:00once again runtime packages will be
23:02something your code imports and uses
23:06while doing an actual work development
23:08related packages or dev dependencies
23:10will is something something you use to
23:12write compile or check code but not
23:15something you need while running that
23:17particular code in production. Okay. So
23:19that will be the
23:21uh difference between dependencies and
23:22the dev dependencies. Now you can see
23:24that clearly you will see these dev
23:26dependencies of this TypeScript compiler
23:28or dev runner or let's say we have a
23:30lint package this you need when you're
23:32going to do your development. Okay. So
23:33this will be the proper definition.
23:36Now what will be the dependencies then?
23:38So I'll take one example let's say
23:40express. Now express will be your
23:42dependencies. Now express is your actual
23:45running API server that you're going to
23:47import and you're going to use in your
23:49code. So that means that particular code
23:51when you're going to run inside in
23:52production send you need that express
23:55package right? So whenever you're going
23:56to run or build that code in production
23:58first you need to install that express
24:00package then only you can use that
24:02right? Let's say what will happen? Let's
24:04say you're missing some dependencies and
24:05you try to run. So your build will fail
24:08and your app can crash also you're
24:10getting. So that is the definition or
24:12difference between dependencies versus
24:14the dev dependencies. So I think this is
24:17all about this one. Now what else? Maybe
24:19let's understand some of the npm uh
24:22script also. Right? Let's do one thing.
24:24What are we going to do? Right? Maybe
24:25let's create one folder here. So I'm
24:28going to create a source folder. Okay.
24:29Source folder means inside this I'm
24:31going to write all my code and here I'm
24:33going to create index.ts file. So
24:35index.ts means this is where I'm going
24:37to write some code. Okay, we are not
24:39doing anything but we are going to do
24:41something. First you have to understand
24:42that how we are going to write script
24:46inside this package dojson and what
24:48actually this script means? You have to
24:51understand that npm scripts are nothing
24:53but that you are doing something. I
24:54already mentioned that one. Let's say
24:56this particular file I wanted to run. So
25:00now for this task what I'll do right I'm
25:03going to add one particular script and
25:05whenever I'm going to run that script as
25:07a shortcut your tsx or your typescript
25:10will understand I need to run this
25:11particular file. So let's see how this
25:13will work. For example let's say
25:16first of all I'm just going to do like
25:18this here. I'm just going to add a de
25:20script. Let's say whenever I'm going
25:22doing development I need to do what? I
25:24need to test my changes right that I'm
25:26doing something if something is
25:27breaking. So here what I'll do remember
25:29I already mentioned we installed this
25:31tsx package right. So this tsx is going
25:34to do what? It's going to help us to see
25:36whenever I'm going to run this
25:38particular script that whether this
25:40particular file code is running properly
25:42or not. So how I'm going to do that? So
25:44I need to watch this file right? I need
25:46to run this file. So use something
25:48called watch. So I'll do tsx watch means
25:50ts I'm telling tsx to watch which file
25:53source/index.ts
25:55file. So that means I'm simply telling
25:57that okay whenever I'm going to do
25:59right. So whenever I'm going to run this
26:01particular npm rundev so if I just do
26:04here nothing will happen. Okay. So maybe
26:06let's do one thing. We can also console
26:09log something here. So you'll
26:11understand. So I'll do right. I'll just
26:13do a log and I'll do hello NodeJS.
26:18And now if I just do npm rundev. So
26:21whenever I'm doing npm. So I'm telling
26:22npm to run what? Dev script. So npm will
26:25go here. It will check. Okay dev means I
26:27need to run this particular file. So
26:30sour/index.ts. If I run here, I'll see
26:32that you're getting node hello nodejs.
26:35Right? So that means tsx is now watching
26:37this particular file. And here if I
26:40let's see if I do save and you see that
26:42now you're getting hello node js2. Now
26:44this is the important of this particular
26:46term. watch means every time you're
26:48going to change something change means
26:50you are changing the code right let's
26:51say I change from hello NodeJS to my
26:54name right so if I save this you'll see
26:56that this DSX this particular package is
26:58watching your code real time and
27:00whenever you're making any change it is
27:02updating this one so this is what script
27:04is going to do now for example in this
27:06particular script what you're doing we
27:08are doing some development work now
27:09let's say you're working on some
27:11database and in the database you need to
27:13do some migration you can add a
27:14migration script and you can do whatever
27:16what it needs to do. Let's say you need
27:17to do something test, right? You are
27:20going to write some unit test. So you
27:22can do also like this. Okay, unit test I
27:24need to write or maybe unit something
27:26like this and you can write a command
27:27here. Let's say you are doing some ite
27:30test. So you can add a script and you
27:32can do whatever command you need to run.
27:33So whenever now next time you will do
27:35npm run ite so it's going to check this
27:38particular script and it's going to run
27:40that. So this is about the npm script.
27:42Why this is very important? because you
27:43need to understand all of these before
27:45we even start writing any code. Okay. So
27:48now I think we have covered almost all
27:49the things and we also covered what
27:52actually package package.json is. Node
27:55modules will have all your dependencies
27:57and the subd dependencies. Okay, you
28:00don't have to change anything here. Now
28:02let's understand one very important
28:04concept. Now I I'm not sure if I should
28:07explain this one now but still I'll give
28:10you some prop basic idea. Okay, we are
28:12not covering much and that is that how
28:14should you create a proper folder
28:16structure in a nodejs although we
28:18haven't covered any uh express or
28:20anything. Okay. So what you should do
28:22right I'm going to give very basic
28:24overview. So don't take this one as a
28:26complete idea. Okay. Because we are not
28:28going to cover like middleware routes
28:30and everything. What you should do right
28:33how I'm going to explain or when I
28:35actually run this nodes you have to
28:37understand that whenever you're going to
28:38create a new folder or you're going to
28:40create any file you need to understand
28:42whether that particular file actually
28:45holding any responsibility or not. And
28:47this is the best way to put anything.
28:50what I'm talking about holding any
28:51responsibility because let's say
28:53currently I'm creating a util folder.
28:56Okay. Now in this utils folder you can't
28:59put any routing related logic. Routing
29:02means okay whenever my UI is going to do
29:05a API call and then whenever you will do
29:07API call it will do what? It's going to
29:09check that particular route or that
29:10particular API route is present or not.
29:12So that means if you're putting your
29:14routing logic inside utils folder that
29:16doesn't make any sense right that is
29:18also bad. Next let's say you are mixing
29:23your service logic
29:26and your DB logic. DB logic means I'll
29:29do DB repository pattern. DP repository
29:32pattern means where you're going in
29:33which file you are going to actually do
29:34some DB queries at the same time there
29:36also you are doing service logic. Now
29:38see you can do that but this is not a
29:40proper folder structure. Okay. Similarly
29:43let's say you are creating a routing and
29:45in this routing you are adding service
29:47logic. This is also bad. Okay. So this
29:49is also bad practice. So what I mean by
29:52this, I'm not going to cover any terms
29:53for now. But you have to understand
29:55remember this particular line that
29:57whenever you're creating any folder or
29:59any file, you need to understand whether
30:01that file holding any responsibility or
30:04not. As simple as that. Okay. Second,
30:07there is one more rule. You should
30:09always have one always have one entry
30:13file. Entry file or one root file. Now
30:16in this case our root file is
30:18source/index.ts. So whenever I'll go
30:20here right package.json whenever I'm
30:23going to run this particular command
30:24these files should hold each and every
30:27information of your entire code. What
30:29else will happen? Let's say I'm just
30:30going to give that you have two routes
30:33you are using something like that or two
30:35utils file helper function you are using
30:37that will be best way to explain. So
30:39what I'm talking about now let's say you
30:42have two more one utils folder and
30:44inside that you have two files one file
30:46you are using here in this particular
30:48root file and the second file you are
30:50not using okay now in your package.json
30:52JSON when you are going to run this
30:54particular command right ntpm rundev
30:56you'll see that the first file or first
30:59util file whatever you have imported
31:01that output you'll be able to see but
31:03because you are not importing the second
31:05file so how [snorts] we are going to
31:06check that you're getting what I'm
31:08talking about so my point is your root
31:10file this particular root file should
31:13contain
31:15these files should contain the
31:17information of
31:20all or information of your entire source
31:25code at the end what you're going to do
31:28right you're going to import all of this
31:29but you need to import let's say you're
31:31not importing something it's not going
31:33to work you're getting what I'm talking
31:35about so something like this so now I
31:38think this is all about now again this
31:40is not the folder structure completely
31:41we have done because until unless we
31:43start express or we'll do some practical
31:46project it will be very difficult but
31:47till this part this is going to give you
31:49almost all the ideas that what actually
31:51node J is why we need to install the LTS
31:54version of NodeJS. We should install
31:56mean we no need to you can install the
31:58latest version also but it's always
32:00better to install the LTS version. Third
32:02what actually npm is what is
32:04package.json right and some of the very
32:06very important concept right uh
32:08dependencies versus dev dependencies
32:11what actually npm scripts are and all
32:13these things. So with this now what will
32:15be the next step right next step will be
32:17see we are not going to create any
32:18project or anything because we need to
32:20cover the npm uh sorry nodejs core
32:22modules. Now first of all you need to
32:24understand what all core modules we are
32:26going to cover here. So what I've
32:28decided right I'm going to cover all
32:29these. So I'm just going to write here
32:31so that you'll understand. So first of
32:32all we will start with process object
32:36process object of nodejs. Second we are
32:38going to cover the path not path maybe
32:40let's start with
32:42env variables I think I can cover
32:44enviables here also
32:48or maybe let's do one thing no let's
32:50cover process object because env
32:52variables we'll do practically when we
32:54are going to do project after process
32:56object let's cover the path module very
32:58very important then we're going to cover
33:00the file system or file system module
33:03then I'll cover the event loop basics
33:06because these things you need to know
33:08else like it will be like incomplete.
33:10Okay. So event loop we are going to
33:12understand that then we are going to
33:14understand some call back extremely
33:16important means like two important
33:18concept. Okay. Why this is too
33:20important? Because this is extremely
33:22important for beginner level of
33:23interview questions right. So when
33:25you're giving interview these interview
33:27questions are very important. What is
33:28the call back? Why we need promise? Why
33:31we need asynav? What is the difference?
33:34Okay, how this is relevant because see
33:36callbacks are extremely important
33:38concept. Okay, so whenever you're going
33:39to write any function let's see that
33:41you're going to install some third party
33:42packages there will be too much using of
33:45call back promise and async coverage. So
33:46these three are very important
33:48non-negotiable you have to learn all of
33:49these we are also going to learn some
33:51event emitter concept then buffers we
33:55also buffers what else we also
33:57understand some of the uh okay crypto
33:59module we have to understand see that
34:01that's the reason I have actually taken
34:04all these important important modules
34:05also everything we can't cover then very
34:08important errors how we can do error
34:10handling properly without using any
34:12packages or anything proper error
34:14handling and also you are going to cover
34:16some of the basics stream concept. Now
34:19here you'll see that we are not going to
34:20cover some of the thing for example here
34:23we are going to not cover worker threads
34:26and we are not going to cover here child
34:29processes. Now these two concept plus
34:33uh some very advanced
34:36advanced level of concepts
34:40these will move to NodeJS
34:45version sorry NodeJS part three now this
34:49will be pure NodeJS advanced module I'm
34:51going to create but not this in this one
34:54because this doesn't make sense because
34:55this will be only too much okay so all
34:58these things we're going to cover in the
34:59next But you can't skip any of these
35:01because everything whatever you're going
35:03to learn we are going to actually apply
35:04in project directly. So first you
35:08complete all of this and then you move
35:09to HTTP module. Okay. This is how this
35:12course will be built. So first we are
35:14going to cover the core modules and then
35:15we'll understand node HTTP module that
35:17will be a completely different section
35:19and then we'll start with our project.
35:21So with this now let's move on to the
35:23next one. Okay everyone. So now what we
35:25going to do right? So we are going to
35:26understand all the core concepts and the
35:28core modules uh that uh you need to know
35:31before you're going to start the HTTP
35:32module. Okay. And each and every file
35:34that we are going to cover will be very
35:36important. Now one thing I wanted to
35:38mention I think I already explained that
35:40one that there are two or three core
35:42modules that we are not going to cover.
35:44Okay. And the first one will be uh
35:46worker threads and child process. Now
35:48child process worker threads will be
35:50little complicated concept and once I'll
35:53upload the node microservices I think I
35:55haven't created any video on node
35:57internals and some very advanced topics
35:59so there will be uh there is a
36:01possibility that if these two videos uh
36:04get good response so I'm going to upload
36:06a part three okay and that one will not
36:08be that much practical so in that one we
36:10are going to only cover node internal
36:12systems and the advanced core modules
36:14okay so first what we need to do right
36:17see uh I think we We have already
36:18installed all of these correct but you
36:20have to understand that when we are
36:21using Typescript right so Typescript
36:23needs to know that how it's going to
36:25compile the code to JavaScript right so
36:27we need a TypeScript configuration
36:29related file and that file we call as
36:31tsconffigjson
36:33so what we are going to do right so
36:35first of all we have to create a
36:36tsconfig dot JSON file and what you need
36:39to do right go to Google and just search
36:41for I think you can use any AI tools
36:43also tsconfig file NodeJS okay so what
36:46this particular file So, TypeScript is
36:48going to read this particular block
36:50whatever you are seeing here and then
36:52it's going to decide that how it's going
36:54to compile the project. Okay, this is
36:56very simple. So, for now what I'm going
36:58to do right, you can copy this exact and
37:00then we'll paste it here. So, first you
37:01need to understand some of the important
37:03parts. Okay, you uh it will take some
37:05time. Let's say if you don't have any
37:07idea. So, once you do some project
37:09you'll see that each and everything will
37:10be uh you'll be familiar that what
37:12actually each and every property is
37:14doing. So, first one is target ES22. So
37:17this target uh what this particular
37:20thing controls so this is going to
37:21controls which JavaScript uh version
37:24TypeScript is going to compile once it
37:26will start compiling your code. Okay.
37:28And in this one we're using uh 20 uh
37:312022 version because this is actually
37:34modern version. So you can use this one.
37:35So you can see that they mentioned that
37:37this is the compile JavaScript version.
37:39Okay. Then we have module note next. So
37:42this is also important. So this is going
37:43to tell Typescript that which model
37:45system we are going to use in the
37:47compiled files. Okay. Now in this case
37:50what this node next means? So here this
37:53is going to match how NodeJS handles
37:56your ES module and your package.json.
37:59Okay. Now uh let's move on to the next
38:02one which is module resolution. This is
38:04almost same. Then you have one very
38:06important which is root directory. In
38:08this one we are going to use the source.
38:10So we can also do like this right. So
38:11this will be your source. So this is
38:13where Typescript is going to check your
38:14source code and based on that it's going
38:16to compile. Okay. So this will be our
38:18source uh folder. We'll keep it like
38:21this. This is our output directory. So
38:23this is where TypeScript is going to
38:25compile all your all your JavaScript and
38:28it's going to keep in this particular
38:29folder dish folder. Then we have some
38:31TypeScript related functionality. If you
38:33already learned my TypeScript video, I
38:35think I have a two videos. I already
38:37covered each and every point in details.
38:39strict uh strict true no implicit any
38:42and strict null checks all of these okay
38:44and now some of the things you have to
38:46understand let's go here okay so you'll
38:48see that ES module uh inter op so what
38:51this is going to do right so this is
38:52going to this going to make default
38:54imports from your common JS package and
38:57it will be easier to use okay this is
38:59when this is helpful so this is going to
39:01be very helpful when let's say you have
39:03a node package and that particular node
39:05package actually written in older module
39:08style okay So that is the reason they
39:10mention that this is going to support
39:12common JS and ES module inter. Uh then
39:15what else? Okay, this is important. So
39:17include is nothing but this is going to
39:20this is where you're going to have your
39:21code and exclude means we're not going
39:23to include node modules and the bish
39:25folder where we are going to have our
39:28compiled files. Right? So this is where
39:29we are going to have your build files
39:31and this is your external packages. So
39:32we don't need the node modules. Now why
39:34this is very important because you have
39:36to understand why we need this
39:38particular file and you'll see that
39:39whatever project you are going to create
39:41if that particular project is using
39:43TypeScript you are going to see this
39:44TypeScript configuration file. So this
39:46is one particular uh section we I wanted
39:49to cover. Now with this so what are we
39:51going to do right? So in the next part
39:52we are going to start learning all the
39:55core modules and each and every core
39:56modules will be very very important. So
39:58let's start with that in the next part.
40:01Okay. So let's start with the first file
40:03which will be so I'm just going to
40:04create here 01 and let's do process
40:08object. TS.
40:11So let's close all of these. So first of
40:14all what actually process module is
40:16right. So see process is nothing but
40:18process usually represent your current
40:21nodej or current running nodejs program.
40:23Okay what actually we are going to
40:26achieve from this particular module or
40:28what actually this is going to give you
40:30access. So this is going to give you
40:32some of the very important concept some
40:33of the runtime information you need. For
40:35example let's say you need some env
40:37variables that we are going to use. What
40:39I mean by env variables? So let's say in
40:41your project you are going to use some
40:42password or maybe let's say you're going
40:44to use some secrets. So those secrets
40:46you're not going to hardcode in your
40:47code right. So what you need to do you
40:49need to keep those particular
40:52sensitive information in a certain file
40:53and we usually call that one as a env
40:56file right. So this is where you are
40:57going to keep all your env variables. So
40:59this process object is going to give you
41:00the access or this is going to give you
41:02certain functionality so that you will
41:04be able to read those variables and you
41:06can use in your code. Okay. This is also
41:08going to give you some of your command
41:10line arguments.
41:12Okay. Also, this is going to give you
41:14some of the uh methods that from where
41:17you will be able to exit your code.
41:18Let's say something goes wrong. So,
41:20you'll be able to exit. Also, uh I I'm
41:22not sure if some other t uh teachers
41:25usually cover this. This is also going
41:27to give you some process life cycle
41:30events. Okay. This is also very very
41:32important. Okay. So now how this is this
41:36is going to be very much important in a
41:37real backend project. We see at the end
41:40you have to understand whatever module
41:41you are going to cover whether that is
41:43actually useful in a real world or
41:45NodeJS project or not. Okay. Uh why?
41:48Because why it's very important because
41:50there is no point of learning all of
41:52this if you're not able to use this one
41:53in a real project. So in a backend
41:55project this is let's say you're going
41:57to read some your backend code you read
42:00backend code from your env file. So this
42:02is where you need this process or let's
42:04say maybe let's say you need to read
42:06your secrets
42:08correct maybe let's say secrets can be
42:10your DB URL means your database URL or
42:13your API keys or there can be password
42:16or there can be some Google O secret so
42:19it can be anything right so you need to
42:20read all of these so this will be
42:22helpful you need to let's say you need
42:23to read some CLI arguments
42:27in scripts this is where you also can
42:30use this right So how you are going to
42:33use this one? So we have something
42:34called process.inv.
42:36But from where this process actually we
42:39are going to get. So you need to import
42:41something right. So we are going to
42:42import process from. So we need to
42:45import from node. But this will be from
42:48our process model. And also for this we
42:50need to add the types I think. Okay. So
42:53we need to go to our types sorry
42:55tsconfig.json
42:57and let's add here. So we going to add a
43:00types and types will be node. So save
43:04this and here you can see that now you
43:07are going to get this. So this process
43:09is going to give you something from
43:11where you are going to so you'll see
43:13that if I just do process env you'll see
43:15that this is where we are going to read
43:16our env uh variables. But remember when
43:20we are going to start our actual node
43:22capstone project you'll see that I'm
43:23going to explain one particular package
43:25that is called env. So I just wanted to
43:27mention this one so that you'll
43:29remember. So we have something called NV
43:31and this package is going to help us
43:32directly to read these enviables in a
43:35NodeJS project. Okay, this is very much
43:37helpful. But for now I think this is not
43:39needed. So first you will understand one
43:40thing is that this process environ
43:44variables. So this process env is going
43:46to contains all your env variables.
43:49Right? So now let's say what I need to
43:52do right maybe what I'm going to do
43:54right here. Let's do something like
43:55this. So I'm just going to take a con.
43:57Okay. And I'm just going to do a node.
43:59And maybe what I can do, let's do this
44:01one as node env. And now what I'm going
44:04to do, I'll do process env.
44:07So I'll do process env. And let's say I
44:11wanted to take this from my node env or
44:13else I'm just going to take this one by
44:15default as development. Okay. Now one
44:19thing you have to understand here we are
44:20not checking that how you are going to
44:23use env and everything that we are going
44:24to see actually in the practical project
44:26we are understanding the core module and
44:29what are the bad practices and what are
44:31the good practices that you should
44:32follow for example what will be a bad
44:34bad practice here so let's say you're
44:36doing like this so you'll take a con
44:38port and you're doing 3,00 you should
44:40never do this one okay you should never
44:42hardcode enviables
44:44anywhere in your source code you can
44:46take a default value right something
44:48like this you can take take a default
44:50value but you should always read this
44:51one from a certain file okay so now what
44:55we are going to do right also very very
44:57important I forgot this one these
44:59process enviables uh sorry values that
45:02whatever you'll have these will be are
45:04always either string or undefined so I'm
45:07just going to repeat this one so this
45:08process
45:10envi
45:16string
45:17or undefined. Now why I'm actually
45:19mentioning this particular point?
45:21Consider you have this right? So you're
45:23doing port 4,000 something like this.
45:25You have this particular value. When you
45:28are going to actually use this one using
45:30process envile
45:35what you should do right let's say this
45:36is a number you should always do like
45:38this. So you're going to do port and
45:40then you are going to actually convert
45:41this one to a number. Okay. So you're
45:43going to do like this. So process enven
45:48code or else this will be 3,000. Okay.
45:51So you should always convert this one to
45:53that particular data type that you need.
45:55Okay. So this is another thing I wanted
45:56to mention. Now let's we understand that
45:59how we are going to read this although
46:00we haven't added any file or those that
46:03you are going to discuss later. So for
46:05getting noise I think it's coming from
46:06outside. Okay. Uh like people will be
46:10people will go crazy sometime with this
46:12bikes and everything. So you'll get too
46:14much message. Okay. So this one thing we
46:17understood that okay this is where
46:18you're going to read the enviable.
46:20Second thing we understood that you
46:22should always you should means not
46:25should but use I sometimes you can take
46:27some values by default. For example
46:30let's say if you don't have this value
46:31so it will take always from this uh
46:34default value. If I hover here you'll
46:35see this is what I mentioned that either
46:37it will be string or this will be
46:38undefined. So if you have something
46:40where you need to use that particular
46:42value as a number, so you should always
46:44convert this one to a number. So these
46:46all the practices that you should
46:48follow. All right. So now moving to the
46:49next one. Let's understand another
46:51concept. So I'm just going to comment it
46:53here. So let's do process.org. Okay. So
46:56this is actually arg v. So but inside
46:58I'm just going to explain this one as
47:01process.org. So let's go here. So you'll
47:04see that this is the built-in property.
47:05Now here why I actually open this one
47:07you need to understand one thing that
47:09[snorts] this is a built-in property
47:11that returns an array containing the
47:14command line arguments. The important
47:15part is that the actual custom argument
47:18that you're going to pass to your script
47:20that will start from index two. Why?
47:23Because these usually look like this. So
47:26first two elements okay you see that the
47:28first two elements in the array are
47:29always reserved by the node js. So the
47:32first one process.org
47:34zero will be the absolute file path of
47:37the node just executable running the
47:38script. The first index will be absolute
47:42file path of the JavaScript file that we
47:44are going to execute and the third one
47:46will be any custom input that we are
47:48giving. So consider like this. So you'll
47:50see that we have this particular file
47:52right now how this process.org V
47:54actually looks like. So you'll consider
47:56like this. You have this array and here
47:58you're going to have the first one. So
48:00first one will be the path to the node.
48:02So this will be the node path. Second
48:05one will be path to your file. So to
48:08your file means in this case the path
48:10will be this path. So let's say if I do
48:12a relative path and then if I just
48:14replace it here. So this will be the
48:16path that node is going to execute. And
48:18the third one will be the custom
48:20argument that you are going to give. So
48:21let's I'm just going to run a start
48:23command. So this will start from here.
48:25So that is the reason you'll see that if
48:27I'm not sure if seen some nodes as code
48:30you'll see that whenever there is a
48:31process. Mark V you'll see that it will
48:34always start from index number two.
48:37Okay, index number two means the third
48:38place. So first two always will be
48:40reserved by node. Okay, so this is the
48:42reason this line is very important and
48:44also this is a very important interview
48:46question also. So let's see this one
48:48with example. So I'm just going to
48:49comment it from here also. Let's remove
48:51this. What I'm going to do right, I'm
48:54going to take a command. Okay, now
48:56you're going to understand some of the
48:57concept. Normally in other uh projects
48:59or other videos you'll see that people
49:01will not cover all of these. So here I'm
49:03just going to take the uh this process
49:06with index 2 and then I'm just going to
49:08take by default this will be our start
49:10command. Now what you can do right you
49:13can also run different flags very very
49:15important concept. So let's say I wanted
49:17to I wanted to take a fail crash and
49:19also uh sorry fail command and also I
49:21wanted to take a crash flag not command
49:24my bad. So one I'm just going to take a
49:26fill
49:29uh flag and also I'm just going to take
49:31a grass flag. So how we are going to do
49:34this? So I'm simp simply going to do con
49:37sud fail and this will be process dot
49:40arg and this arg includes fail. Okay so
49:45this is the first thing and we are going
49:47to do like this and then I'm just going
49:49to copy this and let's take one for
49:51crash. So this will be my crash. So here
49:54I'm just going to check if in this
49:56command that we are going to run whether
49:57we have this crash flag or not. Okay. So
50:00now what we're going to do right we
50:02going to run this manually and we'll see
50:03that what uh the output will be. But
50:06before that you also need to understand
50:08another very very important uh uh event
50:10and that will be process on. Okay. So
50:13this is a method and here you can use
50:15this exit method. What this exit method
50:18is going to do. So this is not method
50:20this will be event. Okay. So this exit
50:22event is only helpful or only useful for
50:26the final synchronous code. Okay, you
50:29don't have to start you do not do not
50:31start as sync here. Okay, now why you
50:34might ask me? Because at this point when
50:36you're going to run this process on
50:39right node is already setting down. So
50:41node is already setting down. So you
50:43don't have to do any async work here.
50:46Okay. So when you're going to use this,
50:47when you're going to use this one, the
50:49best use cases will be let's say you're
50:51going to use some final log or maybe
50:53let's say you are going to do some final
50:55cleanup. This is extremely helpful. So
50:57what you can do right so we have process
50:59do onexit and it's going to take a call
51:00back and here I'm just going to give a
51:02code and let's say I'm just going to do
51:04a log here that let's do a log and
51:07[clears throat] let's take so I'll just
51:08do process finished
51:12uh with exit code and then let's pass
51:14the code here. Okay. So now let's save
51:17this. So now what you're going to do
51:18right and also uh maybe let's take one
51:22more uh function here. So let's do
51:25function and I'm simply going to do run
51:27app
51:30and we'll take void.
51:33And here what I'll do right I'm simply
51:34going to do log. Let's log this uh
51:38command also. I'm just going to uh what
51:41we can do right? I think let's skip the
51:44uh this command only. Okay, save this
51:47and also now what you're going to do
51:48right. So first of all we have to check
51:50if this is failing or not. So I'm just
51:52going to do if this fails if should
51:55fail. So in that case I'm just going to
51:57log error and I'm simply going to do
52:00manual
52:02uh failure
52:04triggered
52:05with
52:07fail flag. Okay. And then I'm also going
52:11to take one more and I'll do if this
52:13class. So I'll do suit crash manual
52:16crash triggered with crash flag. Okay.
52:22And then at the end I'm just going to
52:23run this app. So I'll save this. So now
52:26let's go to package uh JSON first. Also
52:30let's go to our script. And in this uh
52:33script maybe first let's take the build.
52:35So I'm just going to use the build sts
52:39C. And then I'm simply going to take the
52:41first one and this will be we are going
52:43to use tsx. I'm simply going to do
52:46source because we have source inside we
52:48have this particular file name. Right?
52:50So we'll copy this. So I'll do source/
52:54uh 01 process object ds. So now save
52:58this. I'll see that what will happen.
53:00First I'll go here clear this and then
53:04I'm going to do npm run and we have to
53:06run the script. So the script will be
53:08first 01. This is the script we need to
53:11run. Enter. And you'll see that we are
53:13getting command start and process
53:15[clears throat] finished with exit code
53:17zero. Right? And what actually zero
53:19means? Now this is also very very
53:20important. So zero means success, one
53:23means failure. Okay. Now what I'll do
53:26right? So I'll go here and see here when
53:29this will fail. Now let's say now we are
53:31doing a manual failure. That is fine.
53:33But consider there is something actually
53:34is wrong. And what you need to do right
53:37whenever you're going to do any
53:38functionality here this is not log right
53:40because see when you're going to actual
53:42production level application you're
53:44going to not going to log something
53:45you're going to do actual some
53:46functionality then you're going to do
53:49process.exit and you'll see that this is
53:51the reason in some code you'll see this
53:53process.exit
53:54one and this one means this is a
53:57failure. You're getting the same thing
53:58you have to do here also. Do process
54:00do.exit exit and then you'll do one. Now
54:04I'll save this and you'll see that first
54:05of all what I'm going to do I'll clear
54:07this and now I can directly do like
54:08this. I'll do npm run 01
54:1201
54:13and then I'm going to do start. Okay, so
54:16this is going to start it. So you'll see
54:17that we getting start command but the
54:19moment I'm just going to do npm run or
54:22let's write it. So I'll do npm run 01 -
54:27start. And now I'm going to give a flag
54:29here. So I'll do hyphen -y fail. Okay.
54:32And you see if I do enter and you'll see
54:35that now manual failure triggered with
54:37fail flag. And there is process finished
54:39with exit code one. Okay. The same thing
54:42you can do with crash also. So we'll do
54:45npm run 01 -
54:48start and then I'll do hyphen crash. And
54:51if I do enter here, you'll see the
54:52manual crash is now triggered and
54:54process finished with exit code one. So
54:56this is how you to use command line
54:58arguments. Okay, this is extremely
54:59important concept. You you don't have
55:01any idea how important these things are.
55:03You'll see that when you're going to do
55:04some express level of project, right?
55:05Let's say you're using express and
55:06you're creating uh some complicated rest
55:08API, you'll see that in your code, there
55:10is a possibility you're going to have
55:12this line or you're going to have this
55:14particular line. Maybe you have you have
55:16read some other source code, you'll see
55:18that this line might be present. And
55:19this is the actual reason of using this
55:21process.exit of zero and process.exit of
55:24one. Okay. So now I think this is uh
55:28done. I think we don't have that much
55:29practical because but still you need to
55:31know all these concept whatever you have
55:33covered. So with this now let's move on
55:35to the next mod module which will be uh
55:38let's cover the crypto module because
55:40crypto is one of the most important and
55:41you are going to actually use crypto
55:43module in a rest API project. So first
55:45we're going to cover the crypto module
55:46and then we'll move to the some other
55:48modules in the next part. So moving to
55:51the next one. So let's create one more
55:53file. I hope that you all are writing
55:55all of this along with me right why
55:57because if your basics are not clear
55:59what I always mention in all my videos
56:01you're not going to be a good developer
56:03in any tech whatever you will learn okay
56:06so what when I'm talking about writing
56:08means try to implement the code that I'm
56:11writing and then pause the video or
56:12maybe let's say later also you can do
56:14and then go and experiment and learn
56:16some more things on the same module and
56:18then try to write some more code okay so
56:20basically what I'm trying to say do not
56:22just write what I'm writing write what
56:25I'm writing plus write something that
56:27I'm not writing you are getting what I'm
56:29talking about means that what will
56:31happen let's you are doing crypto module
56:33you're going to learn so from a uh
56:35tutorial point of view what how much I
56:37can do I can give you the basic idea
56:39this is a module this is the reason this
56:41module exist and these all are the
56:43methods I'm not going to cover each and
56:45everything if you go to the actual note
56:47documentation you'll see that this
56:48particular module if you try to learn
56:50each and everything it will take you
56:51seven 7 days but This is not how you're
56:54going to learn right when you're going
56:56to learn a certain thing you have to
56:58understand what are the things that we
57:00usually actually use in a real project.
57:03So that means what what you need to do
57:05you need to learn from a video learn or
57:08uh read some of the documentation the
57:10best will be read some blogs and then
57:12make use some some some AI tools and
57:14everything and then try to write some
57:16code by yourself. So first what we are
57:18going to do right we going to understand
57:20one more module which is called crypto
57:22module and you'll see that you are
57:23actually going to really going to use
57:25this one in so many projects. Okay, this
57:27is one of the most important module that
57:28you should know. Now, this you're going
57:31to usually import from again node.
57:34Okay, so you can do direct like this.
57:36Okay, crypto. But I usually like this
57:37node and then I'm simply going to do
57:39crypto. So this will be my crypto
57:41module. What actually crypto module is
57:43again this is a built-in NodeJS module.
57:46Okay, so this is already built-in NodeJS
57:48module system. Built-in NodeJS module
57:51system. Okay. So now what you're going
57:54to do, right? So first of all you have
57:55to understand that these you're going to
57:57do or these you're going to use any
57:59security related tasks as simple as that
58:02means consider some of the things I'm
58:04going to give you are going to use a lot
58:07creating random UU ids or you're going
58:10to use normal ids you you can also use
58:13this one create
58:16secure token very important hashing data
58:20extremely important okay you are going
58:22to use a lot to hash data
58:25also very important sometime we going to
58:27use this one to verify I'm just going to
58:29do to verify if the data was changed or
58:35not changed so I'll do data was not
58:36changed something like this okay uh what
58:39else also encryption and uh decryption
58:42so I'll do encrypt and decrypt so all
58:46this will be the most used functionality
58:48that you're going to do in this one
58:50we're going to understand some of the
58:51very important methods so first will be
58:52crypto dot
58:54random I think it's called U ID this one
58:58okay random UI ID then random bytes
59:02something called create uh has and then
59:06also you have create hmax something like
59:07this and you'll see that if I do create
59:09only you're getting this many things and
59:11it's almost next to impossible for me to
59:13cover each and everything right so we're
59:14going to only cover the things that we
59:16usually use most so first let's start
59:19with crypto dot random uu U ID. Okay. So
59:25why why actually you need this one. So
59:27first of all you have to understand what
59:28UID means. So this is means uh if I'm
59:31not wrong it's called uni universal uh
59:33unique identifier something like this.
59:35Let's check once. So I'll do UID full
59:39form universal or universal versially
59:42I'm not universal unique identifier.
59:44Okay. So universal unique identifier. So
59:47this is nothing but it's a uh 128 bit
59:50level. But let's understand how much I
59:52know. Now I'll try to explain in a
59:53simpler way. So U ID I think we have
59:56already seen it's called universal
59:57unique identifier. This simply means
59:59when you need a unique ID right? So you
1:00:01need a unique ID you're going to use
1:00:03this. This can be most used will be user
1:00:05ID something like this. You have your
1:00:07order ID. You're creating some payment
1:00:08system session ID. Okay this is also
1:00:11important or request ID all these
1:00:12things. Okay. Now here uh what we are
1:00:16going to do? So let's I'm just going to
1:00:18do this one as request ID. And you
1:00:20simply going to do crypto dot random uu
1:00:25id. That's it. You don't have to do
1:00:26anything here. And you just simply do
1:00:28log. And I'm simply going to log this
1:00:31request ID. Okay. So if I save this. So
1:00:34let's run all of these side by side. So
1:00:36I'll go to package.json. I'll create one
1:00:38more. So I'll do 02. This will be tsx
1:00:42source slash
1:00:44and let's copy the name
1:00:48dot ts. Save this and then we going to
1:00:52clear and then I'm just going to run npm
1:00:54run 02. Why? Because we have this
1:00:57particular script. And if I do enter and
1:00:59you'll see that you're getting a unique
1:01:01UU ID. Okay. So next one. So let's go
1:01:04here. So next will be random bytes.
1:01:07Okay. So you're going to do crypto dot
1:01:09random bytes.
1:01:12Okay. Why actually you need this? You
1:01:14also need to do actually use cases,
1:01:15right? So this will be when you're going
1:01:16to create secure random bytes. This is
1:01:19usually useful very useful when you're
1:01:21going to do some pass password reset
1:01:23feature. So let's say you're going to
1:01:25create a password reset token and then
1:01:27user is going to validate you are going
1:01:29to validate validate the user based on
1:01:31this reset token or let's say you wanted
1:01:33to pass a email verification token. This
1:01:35is also very important, right?
1:01:38session secret and also you can also use
1:01:42this one in API keys also. Okay. So now
1:01:45let's see if I just try to do like this.
1:01:47So I do random bytes and then I'm simply
1:01:49going to do like this 16. Okay. Okay.
1:01:51Let's not import this one directly like
1:01:53this for now. Let's keep it. So what
1:01:55actually mean by this? So it's simply
1:01:57telling that okay give me random bytes
1:01:58but give me 16 random bytes. Okay. So
1:02:02how this usually works? So first what we
1:02:05going to do right? So first I'm just
1:02:06going to do a give me reset token. So
1:02:09I'm just going to do crypto dot random
1:02:11bytes give me 16 random bytes and then
1:02:14we are going to convert these bytes to a
1:02:16hex format. Okay. So in hex format what
1:02:19will happen right? One bite will become
1:02:21two characters. Okay. So that means when
1:02:24you're going to get a 16 byt mean it
1:02:26will become a 32 character string. Very
1:02:29important right? So you can just verify.
1:02:31So here what I'm going to do so is one
1:02:34byte is two characters
1:02:38because if I have random bytes
1:02:4316 means 32 character string. Let's see.
1:02:50Ah my bad. So it's not actually two
1:02:52characters but it will become two
1:02:54characters string when you convert into
1:02:56a hex format. I think this I mentioned
1:02:57that you have to convert this one to a
1:02:59hex format. So what I mean by this? So
1:03:00this is simply telling that you create a
1:03:0216 uh bytes but you're going to do a two
1:03:05string and then you're going to convert
1:03:07this one to hex format. So this time it
1:03:09will become I'll show you my bad. Yes.
1:03:12In hex format only I'm asking
1:03:21yes. So when you're going to format raw
1:03:23data as hexadimal every single bite into
1:03:26translate into uh exactly two text
1:03:29characters means in this case now this
1:03:3116 byt will become a 32 character
1:03:33string. So this will be a 32 string and
1:03:37also we can validate this. So now here
1:03:39I'm simply going to do log and I'll do
1:03:42reset token save this and let's run once
1:03:46again. So I'll do clear
1:03:49and you can see that this will be your
1:03:51and you can also check this right 1 2 3
1:03:534 5 6 7 8 9 10 11 12 13 14 15 16 17 18
1:03:5919 20 1 2 3 4 5 6 7 8 9 10 11 12. Okay,
1:04:04so this will become 32 characters and we
1:04:07can verify is this 32 characters. Why
1:04:10I'm explaining you'll understand that
1:04:11why I'm going into too much details
1:04:13because this is what we are going to
1:04:14actually use in a project.
1:04:16See this string is exactly 32
1:04:18characters. It's a valid MD5 has or a 16
1:04:22by hexadimal string. Since 16 byt into
1:04:24two characters. So this will be 32
1:04:26characters. Okay. And you'll see that
1:04:28exactly these particular things you're
1:04:30going to use actual project when you're
1:04:31going to build this. Let's say password
1:04:33reset token feature email verification.
1:04:35You're going to use this one. Okay. Then
1:04:37next we have something called crypto dot
1:04:40I think we let's do create h has because
1:04:42this is also important. Okay. Create
1:04:43hash. So create h has will be has what
1:04:47what actually has is going to do? So h
1:04:49is going to convert your data to a fixed
1:04:51length string. Okay, fixed length
1:04:54string. Very important, right? So now
1:04:57consider you have something like this.
1:04:58So you have a hello.
1:05:01Let's do like this. Hello. And this you
1:05:03wanted to convert to a hash. Something
1:05:05like this. Now here directly from a hash
1:05:09to this hello is not possible. Okay. So
1:05:12now what you have to do right hashing
1:05:15what whenever you have something called
1:05:17hashing it always one way. So that
1:05:19simply means let's say you have a input
1:05:21that input can become has but you can't
1:05:25convert that has directly to the
1:05:27original input. You can also verify. So
1:05:29if I just do has
1:05:32one way means if I if I have a input
1:05:38right that become has I can't convert
1:05:45that has back to same original
1:05:50input correct so let's see
1:05:55uh see so it's a strictly one way
1:05:57cryptographic operation means you can't
1:06:00reverse it. Okay, this is very
1:06:02important. So that is the reason I
1:06:04mentioned that H is going to convert
1:06:05your data to a fixed length string and
1:06:08it is one way. One way means if your
1:06:10input becomes H has you can't convert
1:06:13that has back to the original input.
1:06:15It's not possible. But this is actually
1:06:17helpful if you wanted to check your data
1:06:19whether that particular data changed
1:06:21cast key or let's you wanted to compare
1:06:23something. So let's say I have a con and
1:06:26I'll do text and maybe let's do hello
1:06:28node or whatever you wanted to take and
1:06:30let's say I wanted to create a has and
1:06:32then I'm simply going to do crypto dot
1:06:34create has and here I'm simply going to
1:06:37give algorithm. So in this case I'm
1:06:39going to give sh a uh 256 and here I'm
1:06:43simply going to do dot update to text
1:06:47and then what you have to do you have to
1:06:48digest this one to a hex into hex
1:06:52format. Okay. And then you can just log
1:06:54this hash here. Okay. So now if I save
1:06:59this, I think we have to pass the text
1:07:02this one this text. So if I save this,
1:07:05you'll see that this will create a hash.
1:07:09Okay. So it's going to create a hash
1:07:11here. So this is about how you can make
1:07:14use of this crypto.re.
1:07:16Then we have something called let's do
1:07:18this one also, right? Maybe let's create
1:07:21uh let's understand one more which is
1:07:23also very important that is called
1:07:24crypto dot create hmac.
1:07:29So what this is going to do? See first
1:07:31of all you need to know what actually
1:07:33HMAC means. So it means you have a hash
1:07:36based message authentication code
1:07:39something like this right? It's like a
1:07:41hash only. It's similar to h has but
1:07:43it's like more like of a think like a
1:07:45secret key. You have a secret key. So in
1:07:47normal has right if you have a normal
1:07:49hash something like this you have a
1:07:51normal has
1:07:53normal has how it will work. So you have
1:07:55a data and you're going to convert this
1:07:57one to has something like this in HMAC
1:08:00what will happen to explain in a simpler
1:08:02way you have a data but at the same time
1:08:05let's say this is a secret so you have a
1:08:06secret you have a secret okay what I'm
1:08:11doing man and this will be your signed h
1:08:15okay so this is the difference
1:08:18so now okay one of the best use of using
1:08:22this create hmac will be whenever you're
1:08:24going to do any kind of webbook related
1:08:26uh functionality right these can be
1:08:27helpful or maybe signed token also
1:08:30signed tokens right so let's say I have
1:08:33a secret key so I'll do secret key and
1:08:36this will be let's say my super secret
1:08:42key something like this and then I have
1:08:44a message also here so message and let's
1:08:47do user
1:08:49id equal to 1 and here now you are going
1:08:52to create a signature so how We're going
1:08:54to create a signature. So, we'll do
1:08:56crypto dot create
1:09:01crypto dot create
1:09:03h uh no create uh hmac here. You're
1:09:08going to give so I'll do sh a 256
1:09:12and you're going to pass the secret
1:09:14here. Okay. So, you have to pass the
1:09:15secret here. So, do secret.
1:09:19Let's do secret. So, I'll do secret.
1:09:24and then you're going to update. So now
1:09:25I'm going to update my message and then
1:09:27I'm just going to digest this one to X.
1:09:32So this is going to create a signature
1:09:35has. So this is going to create a
1:09:37signature has. Okay. So now you can also
1:09:39verify this one. So let's say first
1:09:42let's log this
1:09:48and let's clear this. And if I run this
1:09:50one, you'll see that it's going to
1:09:51create this last one. Okay? So it's
1:09:54going to create a signature has. Okay?
1:09:55Because you're passing a data plus
1:09:57secret. Previously, you are only passing
1:09:59data. See, you're not passing any
1:10:00secret. So that is the difference. So
1:10:02now let's say you want to do verify. So
1:10:04do con signature
1:10:07verify something like this verify. And
1:10:11then you can do crypto dot create hmac.
1:10:17And here you're going to pass the so
1:10:19I'll do sha 256
1:10:22pass the secret and here what you can do
1:10:25right uh
1:10:28same thing you'll do update
1:10:31update the message update message mean
1:10:34this message and then you're going to
1:10:36just do dot digest to x and now what you
1:10:41can do right if I do log and you'll see
1:10:44so I'll do signature
1:10:46is valid and matching and I'm simply
1:10:50going to do if this signature that I
1:10:51created this one this signature and this
1:10:54signature to verify both are same or not
1:10:56so you'll understand so do signature to
1:10:58verify okay so if I save this and let's
1:11:01see what you're getting
1:11:05and you can see that is getting
1:11:06signature is valid and matching it's
1:11:08true and makes sense so this is where
1:11:10what you can do right consider this we
1:11:11are doing manually but in a real project
1:11:13you are going to let's say getting this
1:11:15token from some other place And you're
1:11:16going to verify. So you'll be able to
1:11:18verify this one using this create uh
1:11:20HMAC this particular method. Okay. So
1:11:23now if you go here right so you
1:11:25understood some very important things.
1:11:27Random U ID is going to create unique
1:11:30ids. Random is going to do what? It's
1:11:32going to create random tokens secret
1:11:35random tokens. You have create h has
1:11:37create is going to do what? It's going
1:11:38to create oneway hash. That is very
1:11:40important. I already explained. and
1:11:42create hmac is going to create h has
1:11:44using a secret key using a secret key so
1:11:47with this this particular module is now
1:11:50completed and now let's move on to the
1:11:51next one all right so let's move on to
1:11:53the next one which will be uh so let's
1:11:55create another file and this will be OS
1:11:57module okay now this will be sort but
1:12:01still it is actually important so that's
1:12:02the reason actually I've decided to keep
1:12:04this so first of all OS means I think we
1:12:06all know this means operating system
1:12:08right so what OS module is going to give
1:12:10you information is going to give to give
1:12:12you the information about your license.
1:12:14Okay. Now, some of the common use cases
1:12:16now all those see I'll be very honest
1:12:18when you're going to create any rest
1:12:19APIs until unless you're going to have
1:12:20very specific functionality related to
1:12:23that particular project you're not going
1:12:25to use that much of this particular
1:12:27model. Okay. But some of the very
1:12:29important use cases will be let's say
1:12:31you wanted to check your operating
1:12:32system. So first of all let's say you
1:12:34wanted to check your CPU information. So
1:12:37in that case this is important. Or let's
1:12:38say you wanted to check your memory
1:12:40information. This is also uh important
1:12:42and also sometimes you also need to find
1:12:44your home directories or let's say you
1:12:47wanted to check some temp directories.
1:12:49So that time also this is important. So
1:12:51how we are going to use this? So first
1:12:52of all we are going to import something.
1:12:54So I'm going to import star as os from
1:12:57so we are going to use from node and
1:12:59this will be from os module. Okay. So
1:13:02first of all let's do one thing. I'm
1:13:03just going to create a very simple
1:13:04function and we are going to understand
1:13:06one by one. So I'll do run os demo. what
1:13:10this is going to return let's give void
1:13:12and then let's start with the first one
1:13:13and I'm going to take this one as let's
1:13:15say platform okay and here I'm simply
1:13:18going to do osplatform
1:13:20now let's do one thing let's uh also
1:13:23maybe run this so I'm just going to run
1:13:25this here and let's save this go to
1:13:28package dojson let's create one more so
1:13:31I'll do 03 so do tsx source/
1:13:35and this will be rename copy is
1:13:40ds save and now first of all let's start
1:13:43with the first one which will be what
1:13:45you're getting in the platform correct
1:13:47so I'll do npm run 03 enter and you can
1:13:50see that we are getting platform darwin
1:13:52the platform this will defer whatever
1:13:53platform you're using and based on that
1:13:56this will change uh what will be the
1:13:58next things let's check the architecture
1:14:00so I'm just going to do console.log log
1:14:02and let's do architecture and this will
1:14:04be your OS.arch arc and this will give
1:14:07you the architecture right return the
1:14:09operating system CPU architecture for
1:14:11which the NodeJS binary was compiled
1:14:13okay so let's save this and if you just
1:14:16clear and run one second and you'll see
1:14:18that you're going to get the
1:14:19architecture okay you can also get your
1:14:22OS type now also you might be thinking
1:14:25these things are not that much difficult
1:14:27but actually these are actually your
1:14:29node basics right these is going to make
1:14:31you better the all these concepts right
1:14:33is going to make you better node
1:14:35developer consider let's say one person
1:14:36is starting [snorts] learning NodeJS and
1:14:38directly jumping to the rest API but on
1:14:40the other side what you are doing you
1:14:42are learning each and every NodeJS core
1:14:43module you know how you can create APIs
1:14:46using only HTTP module how you can
1:14:48create routes and everything and then
1:14:49you jump to express a node it will give
1:14:51you way better advantage whenever you'll
1:14:53be going for interview especially for
1:14:54interview this will be a game changer
1:14:56all these modules whatever you are
1:14:58seeing and I can guarantee whenever
1:15:00you'll go for any very complicated
1:15:02interview right where they will test
1:15:03your concepts concept conceptual
1:15:05concepts especially they are going to
1:15:08ask you questions from all these module
1:15:09I can guarantee even if you go to lead
1:15:11late code discussion and everything
1:15:12you'll see that these kind of questions
1:15:14so many people usually get so this will
1:15:16be your OS type so let's run again and
1:15:19you'll see that you're going to get your
1:15:20OS type also here what else you can very
1:15:23important you can also get your OS
1:15:25release also so let's say here you can
1:15:27do write OSR release okay and if you
1:15:30save this let's see if I run once again
1:15:33you're going to get that also Okay, what
1:15:35else? As I already mentioned that you
1:15:37are also going to get your home
1:15:38directory. So let's I'm just going to do
1:15:40home directory.
1:15:43And what you can do you can do os doome
1:15:45directory. Okay. And the same way you
1:15:47can also get your temp directory. So
1:15:50let's see if I do console.log and let's
1:15:52do temp directory
1:15:55and this is going to give you this temp
1:15:57directory. Save this.
1:16:01And you can see that this is my home
1:16:03directory and this is my temp directory.
1:16:06Now how you're going to get the CPU
1:16:08information? Now CPU information you're
1:16:10going to get from so do con let's do
1:16:12CPUs. So we do OS dot CPU CPUs and here
1:16:17you can you will be able to get the
1:16:18count also. Let's say if I just do CPUs
1:16:21dot uh I think it's called length. So
1:16:23you'll be able to get the CPU count also
1:16:25here. Maybe let's do one thing or let's
1:16:28expand this one little here and then
1:16:30clear this and then if I run here you
1:16:32are going to get the CPU's count also.
1:16:35Okay. So now uh consider that you wanted
1:16:38to check your CPU model that is also
1:16:41possible. So let's see if I just wanted
1:16:42to give the okay my CPUs dot length if
1:16:46this is greater than zero. So what I can
1:16:49do I can do uh inside this I can do a
1:16:51log and I'll do a first CPU model or
1:16:54something like this. So do first CPU
1:16:56model and I'm simply going to do CPUs
1:17:00I think CPU of zero dot model. I think
1:17:03this is going to give you the model
1:17:04here. Okay. If you do dot you see the
1:17:06model speed times all these things
1:17:08you're going to get. So I'll do model.
1:17:09Let's do the CPUs of 0 dot speed and
1:17:14also I'll do CPUs dot of 0 dot times. So
1:17:19you will be able to get all of this
1:17:20information also. So clear and run this
1:17:23and you can see that first CPU and all
1:17:25this information the speed and
1:17:27everything you're going to get. Okay. So
1:17:29this is done. You can also get the
1:17:31memory information also from here
1:17:32directly. Okay. And let's say for now
1:17:35I'm just going to keep it simple. So I'm
1:17:37just going to log here and I'll do OS
1:17:39dot total memory. See directly you'll be
1:17:41able to get return the total memory of
1:17:42the system memory in bytes. Okay. What
1:17:44you can do, you can also convert these
1:17:46bytes to GB if you wanted to check and
1:17:48also you'll be able to get the free
1:17:50memory also here.
1:17:52Save this and let's clear and if I run
1:17:56all of these
1:17:59so this will be total uh the memory and
1:18:02the free memory all these. So everything
1:18:04you're going to get from this right
1:18:06mostly as I already mentioned OS CPU
1:18:08information you're going to get memory
1:18:10and home and temp directory all these
1:18:12things you you will be able to
1:18:14understand from this particular model I
1:18:16think that's all we don't have that much
1:18:18so what will be the next one next one
1:18:20will be path module we are going to
1:18:21understand that is also very important
1:18:23so let's move on to the next one okay so
1:18:25let's go to the next one which will be
1:18:27path module uh very very important okay
1:18:30this one actually you're going to use in
1:18:32real project okay whenever you're going
1:18:34to build. So first of all, uh what path
1:18:36module actually helps? So this is going
1:18:38to help you to build and read the file
1:18:41paths. Okay, it will help you to build
1:18:44and read file paths first of all. Okay,
1:18:49so first how we are going to do this?
1:18:50We're going to import path from you can
1:18:53see that you're getting the import also.
1:18:54So it will be from node and path module.
1:18:57So now uh how we are going to do this?
1:18:59Now before that we also need to
1:19:00understand some of the bad practices
1:19:02that you should not do. For example,
1:19:04let's say you wanted to get some file
1:19:07file path. Okay. Or maybe let's say you
1:19:10wanted to create some uh folder
1:19:13something like this. Just think of any
1:19:15scenario what you're going to do right.
1:19:17So let's say here I'm just going to take
1:19:19like I have a const and I have a file
1:19:21path something like this. And here what
1:19:23you're doing right? So let's say you
1:19:25have a project root. Okay. This is your
1:19:27project root. This is the root path of
1:19:29your project and then you're doing like
1:19:31this. Okay, I'm just doing uh add
1:19:33uploads plus uh add file name something
1:19:37like this. Now this is not a good
1:19:38practice. So here instead of doing this
1:19:40whenever you're going to have this kind
1:19:42of situation you are going to use path
1:19:44module instead of instead of doing like
1:19:46this. Okay. So how you're going to do
1:19:48this? So this path module is going to
1:19:50give you this very very important
1:19:52methods. There are so many but one of
1:19:54the most important is join. Okay. This
1:19:56path dot join it's going to do what? So
1:19:59it's going to first of all it's going to
1:20:00use correct separator for the correct
1:20:03operating system. This is one of the
1:20:05most core concept or core interview
1:20:06questions also you can understand that
1:20:08why actually you should not do like
1:20:09this. Instead why you should use
1:20:11something called path dot join. Now here
1:20:14you can give that okay this is so or
1:20:16this is going to use as the correct
1:20:19separator
1:20:23for the correct sorry current operating
1:20:26system or current OS now you might be
1:20:28thinking what actually you mean by this
1:20:30now sometimes see whenever we have path
1:20:32let's say we're using Mac it can be like
1:20:34this so let's say have a users/
1:20:37maybe my name let's I have a project
1:20:39folder and let's have a file something
1:20:41like this
1:20:44okay but the same in Windows it can
1:20:46happen like this so let's say you have a
1:20:47C directory something like this and then
1:20:49you have users then you have maybe let's
1:20:51say my name then you have project and
1:20:54then you you have filet txt you're
1:20:56getting so what this path dojo join is
1:20:59going to do it's going to use the
1:21:00correct separator for the current OS and
1:21:03very very important then this is the
1:21:05first thing then you have something
1:21:06called uh here we have something called
1:21:09process
1:21:11CW WD what this is going to do this is
1:21:14going to give you the current working
1:21:15directory. Current working directory
1:21:17means again this can also be interview
1:21:20question that what we mean by current
1:21:22working directory CWD. So current
1:21:25working directory means the folder from
1:21:27where your NodeJS process actually start
1:21:30uh started the path or the folder I
1:21:33think the folder will be better way to
1:21:34put. So the folder from where
1:21:38the NodeJS
1:21:40process uh was started. Okay. So this
1:21:44will be your process CWD. So now let's
1:21:47say what I need to do do right. So first
1:21:49of all I need to get my project root. So
1:21:52what I will do is I'll do con and first
1:21:54of all I wanted to get a project root.
1:21:56So I'll do project root. Give me my
1:21:57project root. So I'm just going to do
1:21:59process and then I'm just going to do
1:22:00CWD. So this is going to give me my
1:22:03project root. Okay. So now let's see if
1:22:05I just do log here and let's log this
1:22:08project root. Save this. Go here. And
1:22:11let's add one more.
1:22:14And I'm just going to do tsx source/
1:22:22paste it here. Save this.
1:22:26So I'll do npm run 04. And you can see
1:22:29that you are going to get your project
1:22:31directory. And see this path, right?
1:22:33this path or the separator can change.
1:22:35If you're using Windows, you can check
1:22:36this. So, because I'm using Mac, this is
1:22:38coming like this, right? So, YouTube
1:22:402026 projects NodeJS 26 one NodeJS
1:22:44basics NodeJS code modules. So, this is
1:22:46my current working directory. This is
1:22:49where I'm actually my NodeJS process
1:22:51actually started previously. So, this is
1:22:53going to give you my project loop. Okay.
1:22:56So, this is the first thing. So, now
1:22:58let's say what we are going to do right
1:23:00now. I'm just going to create some uh
1:23:03hypothetical sees and because we're not
1:23:04creating a proper project right here. So
1:23:07because we need to understand the
1:23:08concept so what I need to do right let's
1:23:10say you're creating some project where
1:23:12user actually uploads some file okay and
1:23:16that we wanted to store that particular
1:23:18file under this particular folder I'm
1:23:20just giving okay we have uploads/ users
1:23:23and let's say the this is my user ID
1:23:25which is 42 or whatever you can take and
1:23:27then I wanted to add this profile.png
1:23:30png. This is what I wanted to upload
1:23:33something like this or I wanted to store
1:23:35right now as I already mentioned that
1:23:38instead of manually you are going to do
1:23:39this what we going to use we already
1:23:41mentioned we're going to use proc path
1:23:43dot join okay because I'm repeating
1:23:45again this is going to use the correct
1:23:47separator based on the current OS or
1:23:50operating system that you you are using.
1:23:52So now what I'm going to do right I'm
1:23:54simply going to take a const and I'll do
1:23:56user ID and let's say I'll do 42 or 43
1:23:5923 whatever you wanted to take and I'll
1:24:01do a original file name this is the one
1:24:03that I wanted to store okay and this can
1:24:05be let's say I have a profile dot let's
1:24:07take the same only okay this one so copy
1:24:10this and then I wanted to take this one
1:24:11I wanted to store this right [snorts]
1:24:14how this will work so first of all I'm
1:24:16just going to do con and I'll do upload
1:24:18file path okay now I wanted to take path
1:24:22and I wanted to take join. So now how
1:24:25how it will work. So first of all I
1:24:27wanted to take my project root. Okay. So
1:24:29this will be my project root and then I
1:24:32wanted to take all the folders or path
1:24:35that I wanted to store in. So in this
1:24:37case I wanted to store in /uploads/
1:24:41users/ user ID which is the dynamic
1:24:43value and then the original file name.
1:24:45So in this case this will be uploads.
1:24:47This is the parent. This is the child.
1:24:50So that means user is child of uploads.
1:24:53So then user will come. So it will go
1:24:55sequentially. You're getting it's not
1:24:57that much difficult to understand. It's
1:24:59simple. And then 42 will come under user
1:25:02folder. That means 42 is dynamic value
1:25:05which is the parent of sorry which is
1:25:06the child of uh users. Okay. So now uh
1:25:10what you have to do let's take the user
1:25:12ID here and then I'm just going to take
1:25:14the original file name. That's it. Okay.
1:25:17What path dojo join is going to do? It's
1:25:19going to create a path string. It is not
1:25:22going to create folders or it will not
1:25:25check whether the file exist or not.
1:25:27This is very very important concept. So
1:25:29we are going to understand one very
1:25:30important concept that path dot join.
1:25:33This is going to create
1:25:36create a path string. It is actually not
1:25:39going to create the folder. It will not
1:25:41create it will not create the folder.
1:25:44And you'll understand which module we
1:25:46are going to use to create the folder
1:25:47later all of this. But this is very
1:25:49important part. So path dot join
1:25:51actually not going to create the folder.
1:25:52It only going to create a path. Okay.
1:25:55And that path will be a string. So path
1:25:57string it's going to create also it
1:25:59doesn't check if I'm not wrong. It's
1:26:01usually not check. It does does not
1:26:03check the uh no it does not check
1:26:06whether the file exist or not. Right? So
1:26:09file exist or not. It's not going to
1:26:11check. So now let's say if I just log
1:26:13this upload file path. So I'll upload
1:26:16file path save this and you'll see that
1:26:19it's going to create a path string.
1:26:21Okay.
1:26:23And you can see that now notice
1:26:25carefully. So user this and that and
1:26:27then we have um one nodejs and you can
1:26:30see this is a string. Okay. So we have
1:26:31one nodejs node js core modules. This is
1:26:34the folder. Inside this we have uploads.
1:26:38We don't have any folder. See it not
1:26:39created any folder. Then we have a
1:26:41users. Then we have 42. And then we have
1:26:43profile.photo.png.
1:26:45So then you might be asking when we can
1:26:47use this. So you can use this when you
1:26:48have to use when you have to actually
1:26:50create the path string. So that it is
1:26:52very very important. It is actually not
1:26:54going to create your uh folder that
1:26:56you're going to understand later.
1:26:57[snorts] Uh what else? I think this will
1:27:00be I think that's all. Okay. Let's
1:27:02understand some of the very important
1:27:04point that how you're going to get some
1:27:05of the properties from this. So let's
1:27:07say I wanted to get the file name. What
1:27:10you can do right? You can do something
1:27:12like path dot base name and then you
1:27:15pass this upload
1:27:17file path. What this is going to do?
1:27:19Path dot base name is going to give you
1:27:22it's going to return the final part of a
1:27:24path. Final part final part of a path.
1:27:31So now in this case whatever we have
1:27:33created right this one. Notice this one.
1:27:35So what this is going to return? So this
1:27:38will be your base name. So this is the
1:27:39final path last one. Okay. So this will
1:27:42be your base name. Base name here. Why
1:27:44this is helpful? Let's say you want to
1:27:45only wanted to extract your visible file
1:27:47name. I don't want the full thing. I
1:27:50only want the last the visible file
1:27:51name. So in that case what you can do
1:27:53that from your full path you will be
1:27:55able to get your base name or file name.
1:27:58So now let's see if I just do log file
1:28:00name here.
1:28:02Save this and you'll see that you're
1:28:04going to get that profile.png.
1:28:07Say you're getting profile.photo.png.
1:28:10Okay. Next, you have something called
1:28:11path extension. So, this is going to
1:28:13give you the extension name. So, let's
1:28:15say if I just going to do okay, I'll do
1:28:17con
1:28:20uh let's do file extension.
1:28:23So, do f path dot extension name. And
1:28:26you can again pass the upload file path.
1:28:29So now save this and let's see if I
1:28:33paste it here. So what you're going to
1:28:34get? You're going to get the extension
1:28:36which will be png. So this is my
1:28:38extension. Okay. Also you will be able
1:28:41to see I'm only discussing the important
1:28:44one and you you'll see that most of the
1:28:46times you are going to use all these
1:28:48properties only in a project. And here
1:28:49you also need to understand that you can
1:28:51also get your parent folder from this.
1:28:53So let's see if I just do path dot
1:28:55directory name and pass the upload this
1:28:58one. So this is going to give you what
1:29:00it's going to give you this one. So it's
1:29:02going to give you uh this uh / project
1:29:05sorry not project this part uploads user
1:29:08and 42 means it's going to give you the
1:29:10parent path here. Okay. So if I just log
1:29:12this
1:29:19uh notice here see users from here. So
1:29:22from here till this part. So till this
1:29:24part notice carefully. So let me just
1:29:26remove this or just complicated. Save
1:29:28this
1:29:31and you notice this one. So this is your
1:29:33full path right and this is your parent
1:29:36path means it makes sense right because
1:29:39see notice carefully the one that I
1:29:42explained that upload upload folder is
1:29:44child of this user folder is child of
1:29:48this user ID which is a dynamical value
1:29:51is a child of this so profile.photo
1:29:53photo.png will be child of this because
1:29:56this is actually inside this particular
1:29:58folder. So that is the reason you're
1:29:59getting this one as your parent folder.
1:30:02Okay. So all these things you'll be able
1:30:03to do. So the most important thing you
1:30:06know what you have to understand that
1:30:07what path dojo join usually does. Second
1:30:11very important that path dojo join is
1:30:13going to create a path string. It will
1:30:15not create the actual folder. See that's
1:30:17why you're not seeing the folder here.
1:30:18So that is also important. And also you
1:30:21are going to get file name, file
1:30:22extension, parent, folder and all these
1:30:24things from using this path dot and all
1:30:27the properties that whatever is
1:30:28available. For example, if you just do
1:30:30here path dot and you'll see that you're
1:30:33going to base name delimiter all this
1:30:35extension format is absolute join all
1:30:37this most of the times I also don't know
1:30:40each and everything right what will
1:30:42happen whenever you're going to create
1:30:43actual project right let's say you have
1:30:44a certain requirement you'll understand
1:30:46what I'm talking about and in that
1:30:48particular project you need to use this
1:30:50let's say matches glove this particular
1:30:52method so you do the web search right
1:30:55and then you'll came to know okay this
1:30:56is what you need to do and that is how
1:30:58you're going to learn thing. You can't
1:31:00memorize each and everything. It's
1:31:01absolutely not possible. And this is not
1:31:03how you should learn all these things.
1:31:05Learn what is absolutely needed because
1:31:06what will happen at most of the times
1:31:08you're going to use path dot join uh and
1:31:11this one uh path.base name and
1:31:14path.extension name. This is also very
1:31:15very important. So that's all about the
1:31:18path module. Very important. Now with
1:31:19this now let's move on to the next one.
1:31:21Okay. So let's move on to the next one.
1:31:23So we'll understand uh timers module.
1:31:25Okay. So again this is another very
1:31:28important and you are frequently uh
1:31:30going to use this one in various
1:31:31project. So what are the things we are
1:31:33going to understand? First of all you
1:31:35have to know that why actually need
1:31:37timers right. So first of all we usually
1:31:40use timers when we want to run code
1:31:42after some delay. So let's say we want
1:31:44to run something after some delay. Uh
1:31:48second would be let's say maybe you want
1:31:50to run some particular code repeatedly
1:31:55uh repeatedly after some interval after
1:31:58some interval maybe let's say you wanted
1:31:59to do something in after every 2 seconds
1:32:02something like this right
1:32:05uh so these two will be the most
1:32:07frequent ones and uh here what are the
1:32:10timer functions that we usually use so
1:32:12first of all we have something called
1:32:13set timeout we have something called set
1:32:16interval
1:32:18We have something called clear timeout.
1:32:22We have something called clear interval.
1:32:25And also there is one more set
1:32:28immediate. Okay. So mostly you are going
1:32:30to use all of these and believe me this
1:32:32is very very important concept like
1:32:34there are lot of places you are going to
1:32:36use set timeout, set interval or even
1:32:38set immediate also. Okay. So first let's
1:32:42do one thing. What are you going to do
1:32:43right? So let's start with a simple set
1:32:45timeout example. So what I'm going to do
1:32:47right, so first let's take a function
1:32:50and I'm just going to do run set
1:32:54time out example. Okay. And here let's
1:32:58return a void. So first of all I'm just
1:33:01going to do log and I'm simply going to
1:33:04give a sequence or else it will be
1:33:05tricky. So I'll do set timeout
1:33:09example started and then we are going to
1:33:13take set timeout. So you're going to
1:33:15take set time out like this and then
1:33:17there will be a call back. Okay. And
1:33:20then here we are going to understand uh
1:33:22sorry not understand we're going to give
1:33:24a delay. So that means we are simply
1:33:26telling that these particular set
1:33:28timeout will run after 1 second because
1:33:31we're giving 1,000 millisecond which is
1:33:331 second. So here we are simply going to
1:33:35do log and here I'm simply going to do
1:33:38that this runs after 1
1:33:44second. Okay. And then after this I'm
1:33:47simply going to do a log one more. And
1:33:49here I'm simply going to do three and
1:33:51I'll do this run immediately.
1:33:54So what will happen right? Node is not
1:33:57going to wait. Node doesn't wait.
1:34:03Okay, that's it. So now let's save this.
1:34:07So first of all, this is one very basic
1:34:09example. So simply what we are doing,
1:34:12we're simply telling that okay, we are
1:34:14running a particular function where we
1:34:15have a set time out. We have given that
1:34:17okay, after 1 second, this is going to
1:34:19run. Okay. So now what we will do,
1:34:21right, maybe let's take one um let's
1:34:24take one simple function first and then
1:34:25we'll do one by one. So I'll do async
1:34:28not async I think we can directly take a
1:34:30function and I'm simply going to do run
1:34:32timer demo and here this is going to
1:34:35return void and here I'm simply going to
1:34:37do run set timeout example okay and here
1:34:41I'm simply going to call this so I'll do
1:34:42run timer demo so for now save this and
1:34:46we'll go here let's go to package dojson
1:34:49so I'm going to 05
1:34:51uh which will be tsx source/
1:34:54and then we have this timers module.
1:34:59Okay. So let's clear this and then I'm
1:35:02simply going to do npm run 05 enter. And
1:35:05you can see that so set timeout example
1:35:08started. This is started. I already
1:35:11mentioned that this particular console
1:35:13here node is not going to wait for this
1:35:16that okay this will run and then we have
1:35:18this. So this one will run and then this
1:35:20one will run. No first it's going to run
1:35:22and then you can see that this runs
1:35:24immediately. node doesn't wait and then
1:35:26after 1 second node is going to run this
1:35:28particular set timeout. Okay. Now this
1:35:30is very important because set time set
1:35:32timeout is one of the most important
1:35:34feature that you are not only need in
1:35:36back end but also there are various use
1:35:38cases you're going to use this one in
1:35:40front side also. So this will be the
1:35:43first one. Now let's say uh how you can
1:35:45clear uh timeout. Okay. So how you can
1:35:48do that? So first of all you're going to
1:35:50take a function and you're going to do
1:35:52run clear time out
1:35:56example
1:35:58and here you're going to do void. So so
1:36:02first of all you're going to take a
1:36:03timer ID and here let's I'm just going
1:36:06to take a set time mode and here let's
1:36:09do let's take this one 2cond timer.
1:36:11Okay. And then I'm simply going to tell
1:36:13that okay this message uh let's do one
1:36:17thing. Let's log here first
1:36:21and then I'm simply going to do this
1:36:23message will not run. Okay. Now why? So
1:36:29first of all you have to do something
1:36:31like clear time out and then I'm simply
1:36:34going to pass this time timer ID. What
1:36:36actually we are doing right? We are
1:36:37actually canceling the timer. We are
1:36:40canceling this particular timer before
1:36:41even it will get a chance to run. And
1:36:44then I'm simply going to do a log here.
1:36:47And I'll do a log. And I'll do uh four.
1:36:50Let's give four because we have this on
1:36:52uh third. So I'll do four. And I'll do
1:36:54clear timeout.
1:36:57Cancelled
1:36:59the 2C timer means it will cancel this
1:37:02particular timer. This will never run.
1:37:04Okay, we are immediately canceling this.
1:37:06So that mean this timer is going to
1:37:08cancel before it will even get chance to
1:37:10run. Okay. So this is why whenever you
1:37:12need to clear some timer if you're using
1:37:15set timeout you can use clear time out
1:37:16and you have to pass that okay that
1:37:18timer okay here which is your set time
1:37:21out that you are keeping in a variable.
1:37:23Okay just try to explain this one in a
1:37:25simpler way and then let's run it here
1:37:28and then we can understand this one very
1:37:29very simple way. So save this
1:37:32and I'll just clear and then run once
1:37:36again.
1:37:37Okay. So you see that set timeout
1:37:39example started this run immediately
1:37:41node doesn't wait clear timeout
1:37:43cancelled 2 second timer means here you
1:37:48can see I already mentioned that clear
1:37:50timeout is going to cancel this
1:37:51particular timer here okay and this
1:37:53message will not run if you wanted to
1:37:56check this just remove this save this
1:37:59and clear once again and you'll see that
1:38:01what will happen
1:38:04okay this message will not run now we
1:38:06are getting this But or else you can do
1:38:08that this message will run after this
1:38:11message will run after 2 seconds. I'm
1:38:12just giving example. Okay. So 2 seconds
1:38:14something like this. Save this. And then
1:38:17here I'll do this one. Let's run once
1:38:19again.
1:38:22Okay. So that means here clear timeout
1:38:24is the respon is actually responsible so
1:38:27that this part will not run. So here
1:38:29I'll just go revert this. So this one
1:38:31will not run.
1:38:35Okay. So this will never run. So this
1:38:37will be how you can use clear timeout.
1:38:40Uh what else is left? Okay. So let's
1:38:42see. Uh set interval. Okay. Set interval
1:38:44and set timeout is actually different.
1:38:47Set interval is going to run the same
1:38:49call back again and again after a
1:38:51certain time after a fixed delay. So set
1:38:54interval is going to is going to
1:38:58run the call back
1:39:01again and again after the fixed delay.
1:39:07Okay, very important and this I think I
1:39:09don't have to explain here also these
1:39:10can be extremely important interview
1:39:12questions also right so what is the
1:39:14difference between set timeout and set
1:39:16interval mostly you're going to get this
1:39:17even they will not ask set immediate but
1:39:19definitely you are going to get if
1:39:21you're giving for beginner level of
1:39:22interview questions right so I'll do
1:39:24function and I'll do run set
1:39:28interval example
1:39:32and here we'll do void so first I'm just
1:39:34going to take a count okay see how we
1:39:36doing this. So I'll do do a count and
1:39:38I'm just going to take an interval ID.
1:39:40So I'll do interval
1:39:42id here. What you have to do? You have
1:39:44to take a set interval. Set interval
1:39:46you're going to take this is also going
1:39:48to take a call back. And here what I'm
1:39:50doing nothing. We are just simply doing
1:39:52count ++. Okay. Just notice what you're
1:39:55doing. You have to understand each and
1:39:56every line. And then I'm simply doing
1:39:58I'm simply doing a log here. And let's
1:40:01do this one as maybe uh last we have
1:40:03given four, right? So let's give five
1:40:05and I'll do set interval.
1:40:09Set interval tick and here you're going
1:40:13to give the count. Okay. And then what
1:40:16I'll do right if see what you're doing
1:40:19if the count is equal to three means the
1:40:21moment count will become three. So in
1:40:24that case what you're going to do you're
1:40:25going to clear this interval. So how
1:40:27you're going to clear the interval? Just
1:40:28like we have done clear time out to
1:40:30clear a interval you're going to do
1:40:31clear interval that okay now I I don't
1:40:33need this interval anymore but if you
1:40:35wanted to do this you have to pass the
1:40:37time out timeout is your interval ID so
1:40:39that means you have to pass this
1:40:40interval ID or else node doesn't know
1:40:42that which interval or which timer you
1:40:45wanted to close or you wanted to clear
1:40:47okay and then you're simply going to do
1:40:49one more log here and let's give six and
1:40:51I'll do set interval stopped so I'll do
1:40:54set interval stopped
1:40:57how we have to give this man. So I'll do
1:41:00six set interval stopped. That's it. Now
1:41:04I think okay this part okay here I'm
1:41:07just going to give maybe let's give this
1:41:08one a 500 uh millisecond or.5 second. So
1:41:12now we save this and then we going to
1:41:14run this set um time interval example
1:41:18and I'm just going to comment this one
1:41:20okay so that you'll not get confused.
1:41:22Save this. Now let's go here clear and
1:41:26let's run one second.
1:41:29That's it. So 1 2 3 stopped. So every
1:41:345 seconds if you do this one let's say
1:41:371.5. Okay. So see what will happen. So
1:41:39it will take some more time but the
1:41:41result will be same. Okay. So let's see.
1:41:43So 1
1:41:462 3 and it will stop. So that means
1:41:50every 1.5 seconds this particular
1:41:53interval will run. It will increase the
1:41:55count. The moment it will become three,
1:41:57it's going to clear the interval and
1:41:58you're going you are going to get this.
1:42:00As I already mentioned, I'm going to
1:42:01make things very simple and see that if
1:42:03you do this on multiple times, do the
1:42:05same example even multiple times, you'll
1:42:07see that you'll be able to do any kind
1:42:08of example. Whatever project you're
1:42:10going to have, you're not going to have
1:42:11any kind of difficulty that what
1:42:13actually you're going to do and then you
1:42:15are going to have one more. Right? So,
1:42:16I'm just going to comment it here. Save
1:42:18this. So, let's take one more which is
1:42:20called set immediate. Now the difference
1:42:22is set immediate is going to run a
1:42:25particular call back after the current
1:42:27synchronous code finishes. Okay. Now set
1:42:30immediate is not going to wait when you
1:42:33have something called set time out. So
1:42:35it's not going to wait for a fixed time
1:42:36like set time out. So it's going to it's
1:42:39it's something like this. So it will say
1:42:41that I'm going to run as soon as the
1:42:44current script is done. So current
1:42:45synchronous code is done. Okay. So if
1:42:47you go here just do this one that what
1:42:49is set immediate right so you have set
1:42:52immediate
1:42:54what's set time out see here it will say
1:42:57that set immediate is going to run after
1:42:58current current runs immediately after
1:43:01the current IO polling phase finishes
1:43:04it's giving the term difficult like for
1:43:07beginner it will be difficult to
1:43:08understand so it's simply telling that
1:43:10okay I'm going to run this particular
1:43:12call back after my current synchronous
1:43:14code finishes immediately but set
1:43:15timeout is going to do what it's going
1:43:17to wait for that time that if you're
1:43:18giving 5 second timer it's going to run
1:43:20after 5 seconds only. So that is the
1:43:22difference. Okay. So now let's see what
1:43:24is happening. So I'm just going to do
1:43:26function and I'll do set im uh immediate
1:43:29right. So I'll do set immediate example
1:43:32and let's give this one a void.
1:43:35So I'll do set immediate.
1:43:39And now uh I'm just going to do here log
1:43:42this.
1:43:45So last we have six. So I'll do seven.
1:43:49So I'll do here set immediate
1:43:54call back. Okay. And then I'm simply
1:43:57going to do log and I am going to do a
1:44:01let's say synchronous
1:44:04synchronous. I need to take the
1:44:06spelling. Okay. You don't have a
1:44:08synchronous here.
1:44:10I think S Y N C H R O N you know US I
1:44:15think this is correct. I don't know.
1:44:17Okay. So the synchronous code after set
1:44:19immediate.
1:44:22Okay. So now let's run this and we'll
1:44:26run all of this. Okay. We going to run
1:44:28this also. And let's run all these also.
1:44:31And I'm going to make this one 1,000.
1:44:34Let's save this. And let's run once
1:44:36again all of this and we'll see what is
1:44:38happening.
1:44:43All right. Set timeout example started.
1:44:45This runs immediately. Node doesn't
1:44:47wait. So that means makes sense. So this
1:44:50is going to run. This is going to run
1:44:52immediately. Okay. Next you're getting
1:44:55clear timeout cancel this one 2 second
1:44:57later. This part and then if you notice
1:45:01one thing very very important. See this
1:45:03part right? So this one inside set
1:45:05timeout you see the uh where it is
1:45:08running. It's running here but before
1:45:10that synchronous code after set
1:45:12immediate means this is actually
1:45:13finished means all your synchronous code
1:45:15already ran and then it will run
1:45:17immediately. See that is the reason
1:45:19after the synchronous code after set
1:45:20immediate you're getting the set
1:45:22immediate call back. So now this will
1:45:24already satisfies what I mentioned right
1:45:26that set immediate is going to run once
1:45:28all your current synchronous code
1:45:30finishes. So once this will run right so
1:45:32you're getting set immediate call back
1:45:33now the set timeout will run. So set
1:45:36time out means this one will run you're
1:45:37getting this will run after 1 second
1:45:39correct and then you're getting your set
1:45:41immediate sorry set interval. So set
1:45:43interval means you're getting count one,
1:45:45count two, count three which is this and
1:45:49then set uh interval stopped and it
1:45:51makes sense right. So this will be the
1:45:53whole flow. Okay. So this will be the
1:45:55difference. Now you can also do like
1:45:57this right? You can also uh implement a
1:46:00promise based timer. Okay. So let's see
1:46:02that also. I thought I'm not going to
1:46:04cover but let's do this one. So I'll do
1:46:05let's say I have a async function and
1:46:08I'm just going to do run promise
1:46:12promise timer
1:46:15example
1:46:16and here this is going to return a
1:46:19promise and this will be void. So how we
1:46:22going to do this? I'm just going to do a
1:46:23log and I'm just going to do a line and
1:46:26let's do this one as waiting for promise
1:46:31best timer.
1:46:33What you can do that let's say you don't
1:46:35want to use set time. What you can do?
1:46:37You can use something called slip. So
1:46:39from where you're going to import this.
1:46:41So let's go to the top and then I'm
1:46:43going to import something from this
1:46:45particular package. So node and then you
1:46:48have something called timers. And then
1:46:50you see you're getting promises. We'll
1:46:51do / promises. And here you're going to
1:46:53get a set time out.
1:46:55And then let's say I just wanted to do
1:46:57as slip something like this.
1:47:01Okay. And this one you're going to use
1:47:03here. So what I can do let's say
1:47:05directly I can use like this this is
1:47:07running and then I can do a because we
1:47:08have a sync and I can use this slip and
1:47:11I can give this 1,000 whatever time you
1:47:13wanted to give the delay okay and then
1:47:16you can simply just do console.log log
1:47:18and then we'll do dot promise
1:47:23promise based timer
1:47:27finishes
1:47:29after 1.5 seconds something like this
1:47:32okay or maybe let's wanted to give 5
1:47:34seconds just to check so let's give 5.5
1:47:37seconds that's it and then how you can
1:47:39run this you just can't directly run
1:47:40like this okay this is the thing you
1:47:42have to understand so this is a promise
1:47:44and this is going to give a catch and
1:47:47Here I'll do error. Let's do unknown
1:47:50because we don't know what is the error.
1:47:52Okay. What I'm doing wrong? Okay.
1:47:58And then uh let's do error here
1:48:02and I'll do timer
1:48:05demo field.
1:48:07And here I'm going to pass the error. So
1:48:10now save this and let's run all of this
1:48:12once again and you'll see clearly what
1:48:14is happening. Enter.
1:48:18three it will stop and see that it will
1:48:20wait 5 seconds and then it's going to
1:48:23run okay so promise base timer runs
1:48:26after 1.5 seconds I think I've given
1:48:28this one change okay change this one to
1:48:30not 1.5 5.5 okay so I think this is done
1:48:33also you can change this one let's say
1:48:35if I change this one to 500 or 1,500
1:48:40let's see what will happen so save this
1:48:44and if you clear this and run once Once
1:48:46again
1:48:48see it run here and then set time out
1:48:51set interval this will can differ like
1:48:54maybe let's say it will run and then
1:48:55this promise based uh this timer will
1:48:57run but at the concept will remain same.
1:48:59So I hope that this will give a clear
1:49:01picture that when set timeout will run
1:49:03when you're going to use set timeout
1:49:04when you're going to use set interval
1:49:06what is the difference between set
1:49:07timeout and set immediate and what is
1:49:10promise based timer. So with this now
1:49:12let's move on to the next one. Okay, so
1:49:14moving to the next one. One of the
1:49:16almost I will say this one is one of the
1:49:18most important concept that everyone
1:49:19should master and that is call back
1:49:22promises and as I'm pretty much sure
1:49:24some of you already know this one but
1:49:25still I will suggest don't skip this
1:49:27because there is a possibility that you
1:49:29are going to get lot of interview
1:49:30queries from this particular section.
1:49:32Okay and this is really important. Uh so
1:49:35we will create so let's do call back
1:49:39promises and async right so we have all
1:49:42these uh let's give asynav module ts
1:49:47okay so first of all let's do one thing
1:49:49let's take a type and we'll make this
1:49:51one as practical as possible and this
1:49:54user okay so this is a type of user and
1:49:57you're doing a API call and this user is
1:49:59going to have a ID number it's going to
1:50:01have a name let's say take this one as a
1:50:03string and let's say this also will have
1:50:05a role. This role can be either this
1:50:07will be a student or
1:50:10let's say normal user or there will be
1:50:11super admin.
1:50:13You can make this one as super admin
1:50:14also. Let's do this one as Z user.
1:50:17So now I'm simply going to do con users
1:50:20and type will be this user of array. So
1:50:23we're going to have arrow of users
1:50:24correct. So you're going to have ID
1:50:26which will be one. Sorry, this will be
1:50:28number. You're going to have a name.
1:50:29Let's take this one as my name. And then
1:50:31I'm simply going to take a role and this
1:50:34role will be
1:50:36so let's take this one as super admin.
1:50:38I'll take one more user or let's say two
1:50:40more user. Okay. So I'll do ID2. Let's
1:50:43do John and let's make this one as user.
1:50:46Okay. And then I'll just paste this one.
1:50:50So, id three. Uh let's do I don't know
1:50:53what uh I uh John or uh let's do maybe
1:51:00Roman
1:51:02and let's keep this one as user.
1:51:05So now what you have to do right the
1:51:07task is uh your interviewer or whatever
1:51:10you're doing your task is you have to
1:51:12actually fetch the list of user or let's
1:51:14say you have to fetch a single user. You
1:51:16have to fetch a single user using
1:51:19callback style using promises using
1:51:22asynchron and both will be different.
1:51:24Okay. Now this is why this is very
1:51:26important because callbacks are one of
1:51:28the most important features that you are
1:51:30going to use in almost all the places
1:51:32and whatever packages even you are using
1:51:34you'll see that there will be uses of
1:51:36callbacks. Okay. So first what we are
1:51:38going to do right uh in this case. So
1:51:41first let's do one thing. Let's start
1:51:43with the uh with the call back example.
1:51:46What actually is a call back? Now that
1:51:47is one of the most important thing. See
1:51:49call back is nothing but in a simple way
1:51:51call back is a function that you're
1:51:54going to pass into another function. Now
1:51:56this is the proper definition. So call
1:51:57back is itself it's a function. Okay.
1:52:00Callback is a function and this function
1:52:04this function you are passing to a
1:52:08different function
1:52:10as a parameter something like this right
1:52:13so now what will happen right so in this
1:52:15case in when you're implementing this
1:52:18one let's say in a nodej project the
1:52:20classic nodej pattern is like this so
1:52:22you have your call back okay this call
1:52:25back either is going to have a error and
1:52:27this is or else this is going to have a
1:52:29result this This is probably one of the
1:52:31most important concept that you should
1:52:33know. Okay, I'm really uh explaining all
1:52:35of these because whatever you're going
1:52:36to implement let's say you're
1:52:37implementing cloudinary file upload and
1:52:39you'll see that there is structure the
1:52:40package structure that whenever you're
1:52:42going to use this you'll see that there
1:52:43will be a call back let's say and there
1:52:45can be a error. So if there is a error
1:52:47you're going to reject if there is a
1:52:49success you're going to get the result.
1:52:50So this is a classic NodeJS call back
1:52:53pattern. Okay. So this is
1:52:57this is a classic NodeJS
1:53:01pattern. So this is how it will work. So
1:53:03look call back pattern
1:53:06how this will work. So let's say I'm
1:53:08just going to create a function and I'm
1:53:10not sure see I can guarantee so this is
1:53:13the challenge pause the video and try to
1:53:15implement what you have to do right
1:53:16let's say you are going to create a
1:53:19function that function is going to
1:53:20receive a call back and that function
1:53:22also is going to receive a user ID so
1:53:25let's see if I'm going to pass the user
1:53:26ID to so it's going to give me this user
1:53:29so let's see if you can do it without
1:53:31watching this part okay then you can
1:53:33resume and you'll see that you will some
1:53:35of you will find this difficulty Because
1:53:37implementing using pure call back let's
1:53:40say you're giving interview is very
1:53:41tricky using asyn you can do it but
1:53:45check whether you can do it using call
1:53:46back or not you're getting so now let's
1:53:48I'm just going to do find user and I
1:53:51will give you one uh practical
1:53:53experience okay this is not just about
1:53:55teaching actually giving proper
1:53:56experience uh that I faced from uh in
1:54:00past I've given more than 100 plus
1:54:02interviews and there is a 100% I
1:54:04remember that I actually got this call
1:54:07back and promise related example in more
1:54:09than 25 to 30 interviews I think even
1:54:13more okay so there is a huge possibility
1:54:15that you're going to get questions from
1:54:16promises implement custom promise you're
1:54:19not going to use the native promise
1:54:21features you're going to implement
1:54:23promise chain all of these you are going
1:54:26to fetch API call using callback you're
1:54:28not going to use any promises or async
1:54:30so these things are very important so to
1:54:32find user and actually I'm telling all
1:54:34of these for those if you're currently
1:54:36Let's say in college, third year, second
1:54:38year, fourth year or let's say you have
1:54:39a less than five years of experience.
1:54:41Okay, consider five years of experience
1:54:42and you're preparing for interview. This
1:54:44can be very important all these things.
1:54:47Uh so this will be a function. So now
1:54:50here what I mentioned that this is going
1:54:51to receive a user ID. So this will be my
1:54:54user ID which will be my uh what is that
1:54:56input and then I'm going to receive a
1:54:58call back. Okay, this is the my call
1:55:00back function. I already mentioned the
1:55:02call back is itself it's a function that
1:55:04we are passing in another function. So
1:55:06this is my another function I'm passing
1:55:07call back as a input and here this
1:55:10callback is going to have either there
1:55:12can be error which will be either error
1:55:15or it can be null okay and then it's
1:55:19going to give me a user okay so it's
1:55:20going to give me user information so
1:55:23here what I'm going to do right so this
1:55:25user will be my this user so I have this
1:55:27user type correct so this is what it's
1:55:30going to receive now you see this
1:55:32pattern this is matching either it's
1:55:34going to give me error or it's going to
1:55:35give give me result okay and then return
1:55:38type will be void that's it
1:55:42return type so this function return type
1:55:43will be this will be void and here I'm
1:55:45simply going to take a set time out now
1:55:48see whatever we have learned so far in
1:55:50the previous part we are applying all
1:55:51these things and here what we can do
1:55:53right let's take maybe what we can do
1:55:57let's take 0.5 second now what I'm going
1:56:00to do right you are actually doing API
1:56:03call think you are doing a actual API
1:56:05got something like this right normally
1:56:07you are not going to use callback okay
1:56:08you are mostly going to use async cover
1:56:10promise but again you should know all of
1:56:12this and this is where you're going to
1:56:13do okay I have my user so I'll do users
1:56:16dotfind
1:56:19so this user is nothing but these users
1:56:21you're going to have so do users do find
1:56:24so do current user
1:56:27and we do current user do ID will be
1:56:30equal to equal to this user ID that
1:56:31you're going to receive this one so Now
1:56:35this is the most important part. What
1:56:37will happen if you don't get this user?
1:56:40Consider that I'm passing user ID 100
1:56:42and that user ID 100 is not present. So
1:56:45what will happen? So this user is not
1:56:47found. Correct? So this is error. So if
1:56:50the user is not found, you need to call
1:56:52this call back. Now this is where
1:56:54student find it uh this one difficulty.
1:56:56So you have to call this callback and
1:56:58what you have to you have to pass error.
1:57:00So here you are going to simply pass
1:57:01okay you have to pass a new error and
1:57:04then I'm simply going to take user with
1:57:06ID this user ID is not present or not
1:57:10found you're getting that's it and then
1:57:13what you have to do you have to return
1:57:14from here immediately so you have to
1:57:16return from this that's it if this is
1:57:20present so that means you are getting
1:57:21result here so let's say you're passing
1:57:23user ID3 so you're going to get what ID
1:57:263 name Roman role user so in this case
1:57:29you're going to all the call back what
1:57:30will be error error will be null because
1:57:33you don't have any error and what will
1:57:36be result will be user so this will be
1:57:39your result now you see that how much
1:57:40easier it is to understand right so this
1:57:43is your uh function where you're passing
1:57:46call back as a input consider you
1:57:48passing in a different function and then
1:57:50you're simply checking we are doing
1:57:51something here you don't know what we
1:57:52are doing something we are doing if we
1:57:54are not getting result we are calling
1:57:55the call back passing the error if we
1:57:58are getting result
1:57:59passing the error as null and user
1:58:02information we are passing but how we
1:58:03are going to call this to call this you
1:58:05can simply just do right so to find user
1:58:07with call back we're going to pass a
1:58:10user ID let's say I'm going to pass
1:58:11three and here what you have to do you
1:58:13have to pass a call back function see
1:58:15it's call back is going to receive error
1:58:17or it's going to receive user correct so
1:58:19here what you have to pass you to pass
1:58:21error
1:58:23and you're going to pass user and now
1:58:26what you're going to get if error you
1:58:28are getting so let's say we're passing
1:58:29error here right so if we are getting
1:58:31error
1:58:34so I'm simply going to log and I'll do
1:58:37call back
1:58:39error and you're going to pass error dot
1:58:42message that's it right and what you
1:58:44have to do again you have to return from
1:58:46here if this is not the case so you're
1:58:49going to do what you're going to log so
1:58:50you're going to get call back result so
1:58:53what will be your call back result so
1:58:55this user this user is going to give
1:58:58give you what ID. This user is going to
1:59:00give you the name and this user is going
1:59:02to give you the role. That's it. So if
1:59:05you save this now, let's I'm going to
1:59:07run this here.
1:59:10Uh let's run copy this.
1:59:18Okay. So do tsx
1:59:22source/ this set this and let's I'm
1:59:25going to run npm ram 06.
1:59:28That's it. So you're getting call back
1:59:30result three Roman user. Why? Because we
1:59:33are passing three. Let's I'm going to
1:59:34pass 30. So 30 is not present. So it's
1:59:36going to give me what error. So here if
1:59:38I just do you see that call back uh with
1:59:41ID 30 was not found. Call back sorry
1:59:44user with ID 30 was not found. So user
1:59:47with ID 30 was not found. So this is
1:59:50calling here and returning the result.
1:59:52It's very much simpler to understand. So
1:59:54this is all about what call back. So now
1:59:57the same example we're going to do using
2:00:00promise and async in the next part. All
2:00:02right. So now let's do the same example
2:00:04using promise and asyncate. Okay.
2:00:06Because at the end you have to remember
2:00:08that when you're going to implement your
2:00:09project, you will be using mostly async
2:00:11because of the syntax. It's much easier
2:00:13to uh use. But again we need to
2:00:16understand this call back that we have
2:00:18call back and then we have something
2:00:20called call back hill. I'll not go into
2:00:22that much details and that is the reason
2:00:24we have something called promises and
2:00:25from promises we have something called
2:00:27async. Okay. So first let's create one
2:00:30more function and let's try to implement
2:00:33this also. So fetch user with promise.
2:00:37So what this is going to receive? It's
2:00:38going to receive the user ID. Again user
2:00:40ID will be type number. And what will be
2:00:43the return type? See remember the return
2:00:45type you have to be very very careful
2:00:46when you're going to use promises. So
2:00:48you have to return a promise. Okay, this
2:00:50is going to return a promise and the
2:00:51type of this promise will be user. So
2:00:54that means we are actually at the end
2:00:57returning a user information that user
2:01:00will have a ID, name and role. Okay. So
2:01:02this is the important line whatever we
2:01:04have done here because what will happen
2:01:07until unless you're going to return that
2:01:08you'll see that you are going to get
2:01:10error because you will not return. So
2:01:12let's say you return a string value,
2:01:14you're going to get error. Okay, because
2:01:15you need to return in this certain
2:01:17format only. So now what will be the
2:01:20next step? Uh these see what I I've seen
2:01:24from my own experience right or
2:01:26professional experience or giving
2:01:28interview that interviewers will not ask
2:01:30you more questions on as they can ask
2:01:32you but in the implementation they are
2:01:34going to ask you that okay you implement
2:01:36this one using promises. Why I'm going
2:01:38to tell you because promises you need to
2:01:40first see first of all to understand
2:01:42asyn better you need to know promises
2:01:44very well to understand promises very
2:01:47well you need to know call backs very
2:01:48well so from callbacks and promises only
2:01:51you are going to get questions in
2:01:52interview I can 100% guarantee and
2:01:55sometimes they will go little like
2:01:58advanc level for example let's say they
2:01:59can simply give you that okay create a
2:02:01promise polyfield or create a promise
2:02:03all polyfield but don't use any native
2:02:05promise features okay so understanding
2:02:08promises. So for example, let's say you
2:02:09are actually returning promise here. So
2:02:11how you going to return a promise? You
2:02:13need to know that okay, I'm going to
2:02:14return a promise. So this will be my new
2:02:16promise. Something like this. Promise is
2:02:18going to have a resolve and a reject
2:02:21property.
2:02:22And this now here what you can do that
2:02:25you can simply take a set time out.
2:02:26Let's I'm just going to take a set time
2:02:27out here because we're not doing actual
2:02:29API call here. And now here let's give
2:02:32this one as 1,000 milliseconds. And
2:02:35inside this we can do like that, right?
2:02:37So this line only we can copy. Now what
2:02:40is the important part? Important part is
2:02:42what will happen if this user is not
2:02:43found. Now in this case now let's see
2:02:46user is not found. What you have to do
2:02:48you you don't have any callable right?
2:02:50So you need to reject. So that is the
2:02:52reason you have something called reject.
2:02:53So promise will give you this reject uh
2:02:56here functionality and here you can
2:02:58actually reject and throw one error.
2:03:00Okay that this particular user ID is not
2:03:03present. user with this ID data was not
2:03:08found. Uh let's do this one. This will
2:03:11be user ID. Correct? So we have user ID.
2:03:14This one this is the case. Now again you
2:03:17have to return. But if this is not the
2:03:19case that means you are actually getting
2:03:20the result. So in that case you have to
2:03:22resolve it. Means now I already have the
2:03:24result. So I'm going to resolve the
2:03:25result and the type of result will be
2:03:27user. That's it. And this is done. Okay.
2:03:31So this will be how we are going to
2:03:33write using promises. Now how we going
2:03:35to call this one? Okay. Now see calling
2:03:38it's very simple. So what we can do
2:03:39right you can just comment out this one
2:03:41for now. And now let's say after this I
2:03:44simply do find uh user
2:03:47what name I have given fetch user I have
2:03:50given right. So let's do find user. Find
2:03:52user with promise. So I'll do find user.
2:03:57Find user with promise. We have to pass
2:03:59the user ID. So let's give I'll give the
2:04:00user ID one and then what this will
2:04:02give. So this is going to give me dot
2:04:04then dot then simply means once promise
2:04:08will run promise will either resolve the
2:04:11value or promise is going to reject the
2:04:12value. If promise resolve the value. So
2:04:14in that case we're going to get that
2:04:16value in our then block. If promise is
2:04:19going to reject the value we are going
2:04:20to catch that particular error. So in
2:04:22this case in the resolve uh block what
2:04:26we'll be getting in the resolve block we
2:04:27are going to get the user information
2:04:29because the user information we are
2:04:30sending. So in this case we're going to
2:04:32get the user here and then you can
2:04:34simply just do like this. So here I
2:04:37we'll go here. Let's say I'm just going
2:04:39to log this only. Copy this and paste it
2:04:43here. And let's make this one as promise
2:04:45result. Okay. And if there is any error
2:04:48so we'll do catch and this will be my
2:04:51error
2:04:52type will be error and here we are going
2:04:55to simply tell okay that means promise
2:04:57is actually catching some error and we
2:05:00don't know what is the error is so I'm
2:05:01just going to do promise error so this
2:05:03will give me error dot message that's it
2:05:06so now let's save this and then we going
2:05:08to run the same thing and we'll see what
2:05:10is happening here so let's clear first
2:05:12run
2:05:14okay so you're getting promise result
2:05:15one sum super admin that is correct what
2:05:18will happen if I give here 100 right now
2:05:20remember this 100 is not present so it's
2:05:22going to throw error correct so if you
2:05:24go here so you'll see that we are
2:05:26getting promise error user with ID sorry
2:05:29user with 100 data means this ID data
2:05:32was not found so this is how we going to
2:05:34write the same thing using promises
2:05:36correct now let's keep keep this one
2:05:38like this now what how we going to do
2:05:40using async async is actually simple so
2:05:43here first of all I'm going to take
2:05:44async now remember you have to know also
2:05:46So that async it actually built on top
2:05:48of promises only. So it's like a
2:05:50promises. The reason we use as because
2:05:52it's much more easier syntax wise and
2:05:54it's also easily you can read it. Okay.
2:05:57So let's say you have written some
2:05:58particular code and other developer is
2:06:00reading your code. They will be able to
2:06:02understand it's not like they they will
2:06:04not be able to understand promise code
2:06:05but it's like much more cleaner. Okay.
2:06:07That is the main reason. Uh so here so
2:06:11first of all you have to do async. So
2:06:13this will be function and I'll do find
2:06:16user with async a now. So I'll do async
2:06:19a. So again this is going to receive the
2:06:22user id which will be number what this
2:06:25is going to return is will be promise
2:06:28and here I'm for now I'm just going to
2:06:30do void and then what you have to do you
2:06:32always have to take a try and catch
2:06:34block right. So if something goes wrong
2:06:36your catch block is going to catch that
2:06:39particular error. So this is where
2:06:40you're going to catch the error and in
2:06:42the try you are going to try to get your
2:06:45result. So in this case let's have a
2:06:46user and I'll do a and then what you can
2:06:49do right you can call this method only
2:06:51find user with promise. So I can here I
2:06:53can simply do find user with promise and
2:06:55you can pass this user id at the end
2:06:58this is promise only admin right uh now
2:07:00here you can just log this I'll do log
2:07:04and simply let's do sync ait
2:07:10and here you can just log this one I'll
2:07:12just do user dot name I think this that
2:07:16is fine only that's it and here what you
2:07:18can do right you can simp message so you
2:07:21have to check if this error is a
2:07:23instance of error. So in that case we're
2:07:26going to render error dot message or
2:07:28else I'm just going to do unknown error.
2:07:30Okay.
2:07:36Okay. That's it. Also you can just log
2:07:39this here. So I'll do log. So I'll do a
2:07:42sync error
2:07:45and then you're going to do a message
2:07:48here. That's it. So save this. Now what
2:07:51you have to do you just have to call
2:07:53this method. So you go here comment it
2:07:55this one and then you can directly call
2:07:57this and then you have to pass the uh
2:07:59ID. So I pass one. So now this is going
2:08:02to go here and it's going to check okay
2:08:05this is async. It's going to wait for
2:08:08this promise to run. It's going to get
2:08:10the result. So it's going to try to get
2:08:12the result. If the result is present
2:08:14it's going to render the result. If
2:08:15there is a error so it's going to catch
2:08:17the error. And if you go here and let's
2:08:19try to run this.
2:08:22So you are going to get async sum. But
2:08:25if I go here and let's say I'll give 100
2:08:28and this is not present. So in that case
2:08:30this will give you a error that this
2:08:33data is not found. So this promise is
2:08:35actually throwing error here. Right? So
2:08:37this promise is going to reject this
2:08:38error and this block whatever it's going
2:08:42to catch the error here. So that's the
2:08:44reason I check in if this instance of
2:08:46error. So we're going to render error
2:08:47dot message. This is actually instance
2:08:49of error. So we are sending the error
2:08:51here and this is getting catched here
2:08:54and that is the reason you're getting
2:08:55the result here. Okay. So this will be a
2:08:59proper introduction or proper way to
2:09:01explain that what actually call backs
2:09:03are. Callbacks are actually most
2:09:04important that why we need call back
2:09:06functions and everything. Uh then you
2:09:08have promises then you have async but at
2:09:10the end as are nothing but it's promises
2:09:13only. But from syntax wise it's much
2:09:15much more easier and readable. So that
2:09:16is the reason we use async. So with this
2:09:18now let's move on to the next one. Okay.
2:09:20So moving to the next one. One of the
2:09:22most important core module that we are
2:09:24going to understand and that is file
2:09:25system module. Okay. And this is another
2:09:28very very important. So let's close
2:09:29everything.
2:09:32Let's open the package.json.
2:09:35Okay. So first of all we have to
2:09:37understand that what actually file
2:09:38system is right. So or why we need file
2:09:41system. So first of all fs means file
2:09:43system. Okay. Now file system is going
2:09:46to allow you to work with files and
2:09:48folders. So simply you think like that
2:09:50you have to create a folder or you have
2:09:52to write some files, you have to read
2:09:54some files, you're going to delete some
2:09:56files, you're going to check your file
2:09:58information. So all those things we can
2:10:00do using file system. This is one of the
2:10:03uh core modules that we need to know
2:10:05before we will start implementing our
2:10:07rest APIs and everything. Okay. So this
2:10:09is going to help you to create folders.
2:10:11It's going to help you to write files.
2:10:13It's going to help you to read files.
2:10:16It's going to help you to check file
2:10:18information.
2:10:20Also going to help you to delete files.
2:10:22So all these things you can do using
2:10:23file system. Okay. Now in node there are
2:10:26three ways we can do this or we can work
2:10:28with file system. The first one is using
2:10:30synchronous APIs. Okay. So we have first
2:10:33sync APIs. Okay. So we have something
2:10:36called uh so FS for file system and then
2:10:39we have read file sync something like
2:10:41this. Okay. So this is where you are
2:10:43going to read the file synchronous way.
2:10:45Then we have call back APIs. Okay. So
2:10:48there are callback APIs that you can
2:10:49use. For example, FS read file. So that
2:10:52is a callback API. Okay. And the third
2:10:54one is promise APIs. And now understand
2:10:56that why in the previous section we have
2:10:57discussed about the callbacks, promises,
2:10:59async all of these. Now why this is very
2:11:01important because see whenever you're
2:11:03going to create project now here in this
2:11:05particular file or whatever things we're
2:11:07going to discuss I can't give you each
2:11:08and every information on file system. So
2:11:10what I mean by this so let's you know
2:11:12this is sync APIs or this is callback
2:11:15API this is promise API based on the
2:11:18project that you are building you need
2:11:20to know or you need to understand okay
2:11:22which method you need to use in that
2:11:24certain position. So let's say you have
2:11:26a particular project you are building
2:11:28and there are two places you need to use
2:11:30file system in feature one you need to
2:11:32use promise API in the feature two you
2:11:34need to use sync API now no one is going
2:11:36to tell you okay that okay you have to
2:11:38do this or no tutorial video is going to
2:11:40teach you all of this okay they can give
2:11:42you the uh path okay this is where you
2:11:44have to use but by practice you need to
2:11:47understand all all of this by yourself
2:11:49and then only you can create your
2:11:50project or else what will happen I'm
2:11:51going to tell you you watch videos after
2:11:54videos you watch blogs blogs use AI
2:11:56tools. You're not going to create
2:11:58project by yourself. Especially if
2:11:59you're let's working in a project or
2:12:01let's say where project not project I
2:12:05will say even I'll say let's say you're
2:12:06working in a company and let's say there
2:12:08is some uh project which is already
2:12:10built and you are only working on the
2:12:13fixes so that the new fixes comes. So
2:12:15you need to understand all of this or
2:12:16say it will be very difficult for you to
2:12:18do all of this. Second, if you're
2:12:20working in some uh freelancing uh work,
2:12:23then this will be much more difficult
2:12:24because in freelancing the requirement
2:12:26can be very very tricky, right? Your
2:12:28client requirement. So why I mentioning
2:12:30all of this means the simple way to
2:12:33explain all of this that don't blindly
2:12:35uh learn [clears throat]
2:12:37whatever I'm teaching here. Okay, try to
2:12:39learn whatever I'm teaching plus try to
2:12:42apply some of the things you should
2:12:44learn by yourself and then create
2:12:46project. This is why or else I'm I'm
2:12:48noticing that some people are actually
2:12:50commenting you don't explain this much
2:12:52you first explain you don't expl do not
2:12:54explain in the file go to whiteboard
2:12:56explain there come back and then explain
2:12:59even if I do that I still what you are
2:13:01going to do you're going to memorize
2:13:02each and everything no one can memorize
2:13:04okay every method you need to know the
2:13:07process and then based on that you have
2:13:09to create projects as much as possible
2:13:12okay so we have sync APIs then we have
2:13:14call back APIs it [snorts] and then you
2:13:16have something called promise APIs. So
2:13:18all these three we have to understand
2:13:20and this is very important and what in
2:13:23modern [clears throat] NodeJS
2:13:24application what you're going to use
2:13:25definitely this is what you have learned
2:13:26so far we are going to use promise APIs
2:13:28correct because promise you see
2:13:29callbacks also you can use but you what
2:13:32will happen if your code is very
2:13:33complicated or the feature is very
2:13:34complicated that will end up in call
2:13:37back help so you're going to write call
2:13:38back inside call back inside callback
2:13:40like that so you're not going to do that
2:13:42so first of all let's do one thing maybe
2:13:44let's uh create first one so I'm just
2:13:47going to create the sync example. Okay.
2:13:50So I'm just going to do function and you
2:13:52do run sync
2:13:55example.
2:13:57Okay. Let's understand this one uh
2:13:59properly. Okay. Because uh this is one
2:14:02of the most important concept you don't
2:14:04understand.
2:14:05So first of all sync APIs are easier to
2:14:08understand. Okay. This is very easy. So
2:14:10it's like a synchronous APIs. Now here
2:14:13what we going to do right? See first of
2:14:15all you have to understand that what
2:14:17actually synchronous uh no not what
2:14:20where actually you should use this this
2:14:21is actually very important right now
2:14:23first of all you need to use this
2:14:24synchronous API when you have some let's
2:14:27say you're creating some small scripts
2:14:29you're creating some small startup
2:14:32startup scripts there you can use this
2:14:34or maybe you're going to build some
2:14:36scripts there also you can use this one
2:14:39uh maybe you're using some local demos
2:14:41something like this you can do all of
2:14:43this right where it is not good, not
2:14:46good or even bad or even bad practice.
2:14:49So where you should not should not use
2:14:51this. So let's say you are uh
2:14:53implementing some HTTP request and you
2:14:55are using this one in HTTP request
2:14:57handlers. This is not good, right?
2:14:59Because by the name you understand this
2:15:00is a synchronous API. Okay. Also let's
2:15:04say you're creating some uh very
2:15:06scalable backend application, your
2:15:07traffic is huge. So when there will be
2:15:10lot of traffic, never use this one. So
2:15:12high traffic APIs do not use this. Okay.
2:15:14[snorts] Or maybe I will suggest this is
2:15:16what I believe that if you're
2:15:17implementing some background jobs and
2:15:19everything right you should not use this
2:15:20sync API also. So in BG or background so
2:15:23do background jobs and everything you
2:15:25should not use this sync APIs. Okay. But
2:15:27first of all let's see that uh how we
2:15:29are going to uh do this one right or how
2:15:32you're going to implement this. So first
2:15:33of all let's do one thing here right? uh
2:15:37let's go maybe here or you can do no not
2:15:39here because this will help you to
2:15:41understand
2:15:43maybe on top
2:15:46so first let's do one thing I'm just
2:15:47going to take a folder okay that I'm
2:15:49going to create so I'm just going to do
2:15:50a demo folder path so I'm going to
2:15:53create a path so how we are going to get
2:15:55the path current directory see we have
2:15:58already discussed in this path module
2:16:00whatever we have learned in the previous
2:16:01section we are implementing the same
2:16:03concept again and again so we need to do
2:16:05path so you're going import node uh path
2:16:08you're going to do a join and then how
2:16:11we going to get the current directory so
2:16:13we have something called process cwd you
2:16:16remember and then I'm just going to
2:16:17create one uh path here so I'm just
2:16:19going to give file system
2:16:22and then let's give this one as file
2:16:24system demo so I'm just going to do fs
2:16:26demo so this will be my folder where I
2:16:28wanted to create this okay and now after
2:16:31this I'm just going to do con sync file
2:16:34path so I need to create a file actual
2:16:37file. Remember in the path module I
2:16:39mentioned that this will actually not
2:16:41create the folder.
2:16:42[clears throat and snorts]
2:16:43It will not create the folder. It
2:16:44doesn't check whether the file exist or
2:16:46not. But this file system is where we
2:16:48are going to actually check all of this.
2:16:49Okay, this is where we are going to
2:16:51actually create the file or folder. So
2:16:53here I'm just going to do path dot join.
2:16:56I'm going to take the demo folder path
2:16:58and let's do this one as sync note txt.
2:17:03So this is where I wanted to create this
2:17:05particular file. Okay. So this will be
2:17:07your project directory file system fs
2:17:10demo and then we're going to have the
2:17:11sync node txt. Okay. So now uh maybe
2:17:15also let's take a another type here over
2:17:17here.
2:17:19So I'm just going to do type. So I do
2:17:21file result. So I just let's take a
2:17:24style. Uh this will be string. Uh file
2:17:27name also I'm just going to take which
2:17:29will be string. Let's take a content
2:17:32which will be string. Let's take a size
2:17:34in bytes and this will be number. So
2:17:38this will be the uh result that I wanted
2:17:41to return. So this will be my return
2:17:43type. So here I'm just going to return
2:17:45this file result. Okay.
2:17:48So now uh how we going to first of all
2:17:52write something in a file. So we need
2:17:55some method right. So this where we are
2:17:57going to use this sync example. So we
2:17:59have something called fs. So fs from
2:18:01node fs. So first of all let's go and
2:18:02import the fs module because we haven't
2:18:05imported the fs module only. So I'm just
2:18:07going to do import file system from. So
2:18:10I'll do node file system. Okay. So now
2:18:13this is where you're going to get a
2:18:15method. So now I'm just going to do
2:18:17what? I'm going to write something. I'll
2:18:19do write content to a file. How I can do
2:18:23that? So I'll do fs dot write and see
2:18:26that we have write file sync. So write
2:18:29file sync is going to write something in
2:18:30a file. Okay. Now here one very very
2:18:33important point if this particular file
2:18:35doesn't exist node is going to create
2:18:38it. Okay. And if the file is already
2:18:41present so whatever node is going to
2:18:43replace the content. So consider here
2:18:45I'm just going to take this and here
2:18:48what it will take it will take the file
2:18:50okay uh fs.path or the file descriptor
2:18:54okay and the actual data. So now I'm
2:18:56just going to give my sync file path.
2:18:58Sync file path mean this is where I
2:19:00wanted to uh save this. I'll do sync
2:19:03file path and then I'm just going to do
2:19:06a container. I'll do created using sync
2:19:10file system and then here what I'll do
2:19:13right I'll give a type. So I'll do u uh
2:19:15UTF8. So this is nothing but this is
2:19:18simply we are telling note that we are
2:19:20writing a simple text. Okay. And now
2:19:23what will happen right? So this is the
2:19:24first thing. Next we have one more
2:19:27method that also you need to understand.
2:19:28So first you understand that fs do.
2:19:30Write file sync is going to write
2:19:32content to a file. If the file doesn't
2:19:34exist you can note it down. Then node is
2:19:36going to create it if the file already
2:19:38exist. So node is going to replace the
2:19:40content. Okay. And what this is going to
2:19:43do this is going to tell node that okay
2:19:44we are writing normal text. Then we have
2:19:46something called fs.append file sync.
2:19:49What this is going to do? This is going
2:19:51to add content at the end of the file at
2:19:54the end of this file. Okay. And it's not
2:19:56going to replace your existing content.
2:19:58So here what you can do, right? You can
2:20:00use something called
2:20:02because by the name you understand,
2:20:03right? So you append file sync and
2:20:06you'll do sync file path and I'm just
2:20:08going to do here give a space. I'll do
2:20:10appended maybe appended using sync fs
2:20:14like this. And here also I'm just going
2:20:16to do UTF8.
2:20:18That's it. So this is two things we
2:20:21going to do.
2:20:24Oh, we have to give comma man. Okay. So
2:20:28now this will to write and this is to
2:20:30append. Now how we are going to read
2:20:32file means read file content. Okay. And
2:20:36for this one we have something called
2:20:38this is also simple. We have to use fs
2:20:40dot read file sync mean we're going to
2:20:42read something. So here we are going to
2:20:45do. So let's say I wanted to read the
2:20:46content of this particular file. con
2:20:50content and we do fs dot read file sync
2:20:55and here you're going to give the path
2:20:57and give the type so we'll do UTF8
2:21:00that's it now remember what will be the
2:21:03type so we have the style file name
2:21:05content and size in bytes so how you're
2:21:07going to get the size in bytes so here
2:21:09you have something called uh fs dot stat
2:21:12uh stats sync if I'm not wrong so here
2:21:15you'll be you'll be getting your stats
2:21:16so you do if you do stats here. So fs
2:21:19do.stats sync. So fs.stat sync is going
2:21:23to give you the information about the
2:21:25file. Okay. Now this is also going to
2:21:27give you the about the file or also
2:21:29about a folder also. And here in this
2:21:32particular variable that will be a
2:21:34property that is called stats dot size
2:21:37and that is going to give you the file
2:21:38size in bytes. So here what you have to
2:21:41do you have to simply pass the sync file
2:21:43path. That's it. So now we are going to
2:21:45return the result. Okay. So first of all
2:21:46what we going to do? So let's start with
2:21:48first we have a style. So this will be
2:21:50sync. Uh then we are going to return the
2:21:53content. Then we also need to return the
2:21:55file. Now here how we going to return
2:21:56the file. Now see this is where you have
2:21:58to see that how uh the previous concept
2:22:01that we have learned so far. We are
2:22:03applying here in this path module we
2:22:05have already covered. This path dobbase
2:22:07name is going to give you the file name.
2:22:09Similarly here also we're going to do
2:22:10path dot base name and here we're going
2:22:12to pass the sync file path. And then
2:22:15you're going to pass the size. How you
2:22:16going to get the size? So this stats is
2:22:18going to give you see here you're going
2:22:20to get a lot of options. So first we
2:22:22need stats dot size. That's it. So we'll
2:22:24save this. Now let's go here and create
2:22:26a main function. So as sync function
2:22:30main and what will be the because we are
2:22:32going to work with promises also. So
2:22:34let's keep promise only here. And then
2:22:36I'm simply going to take a try catch. Uh
2:22:40here this will be error. And I'm simply
2:22:42going to take the same thing that we
2:22:44have learned so far. So if this error is
2:22:46instance of error. So we're going to
2:22:48render error dot message
2:22:51or else I'm just going to do unknown
2:22:53error.
2:22:56And now let's uh log one error.
2:23:00So I'll do file system error and render
2:23:02the message.
2:23:04Okay. And then we're going to call this
2:23:06main. Okay. So this is done. See first
2:23:08of all we have to understand another
2:23:10thing that when you have this demo
2:23:11folder path so we have to check that if
2:23:14this path is actually present or not
2:23:16you're getting what I'm talking about.
2:23:17So how we going to check and if this is
2:23:19not present so we're going to create
2:23:20this particular folder. So that also
2:23:22we're going to understand that how you
2:23:24can create folder. So first let's do
2:23:26like this do insure file no sorry insure
2:23:30demo folder present or exists. So this
2:23:34is what we're going to check. So now
2:23:35copy this and let's go here and I'm
2:23:38simply going to do function and NC demo
2:23:40folder exist. I'm going to return void
2:23:43and now we are going to check that if
2:23:45this is exist or not. So how we going to
2:23:47check exist or not? So we have one
2:23:49method that is called a do.exist sync
2:23:52and [snorts] this is going to tell that
2:23:54okay if this is present. So if this is
2:23:55false so that means this folder is not
2:23:58present. So here we're going to pass the
2:23:59demo folder path. So if this demo folder
2:24:01path is not present, so we need to
2:24:03create a uh demo folder. Correct? How we
2:24:06going to create? So we have something
2:24:07called FS. MKDIR sync. Now this MKDI
2:24:12sync is going to create a particular
2:24:14folder synchronously. Okay, this not
2:24:16will be a sync. This will be
2:24:17synchronously it's going to create.
2:24:19Okay, so it's simply going to fs.m MKDIR
2:24:22sync. Okay, because we are working with
2:24:24sync. And here you're going to pass the
2:24:26demo folder path. And you can pass one
2:24:28more option here and that is called
2:24:29recursive will be true. Now this
2:24:31recursive is nothing but simply telling
2:24:33that you are going to create the full
2:24:35folder path if the parts of it doesn't
2:24:38exist. So it's going to create the
2:24:40complete folder path here. Okay. Now
2:24:43okay now you might be thinking okay why
2:24:45actually you're using this recursive
2:24:46equal to true. So let me explain in a
2:24:48simpler way. So what will happen right?
2:24:50If you don't give this sometime this can
2:24:51fail if your parent folder doesn't
2:24:54exist. So it's simply telling that even
2:24:55if the parent folder is not exist still
2:24:58you are going to create this. So first
2:24:59we're going to use this. So this is
2:25:01going to check if this present or not.
2:25:03And now what I can do right I will go
2:25:05here and I'm simply going to do con sync
2:25:08sync result and this will be my run sync
2:25:12example and then I'm simply going to do
2:25:14log and for now I'll just do like this.
2:25:17I'll do sync result. So save this. Now
2:25:20we'll go here and create one more. So
2:25:24I'll do 07
2:25:26and this will be my tsx source slash and
2:25:29then I'm just going to take rename copy
2:25:31this
2:25:33paste it here and then let's run this
2:25:36and see we'll see what will happen. So
2:25:37first I'm just going to npm run 07.
2:25:39Enter. And you can see that now we
2:25:41already have a file system folder
2:25:43created. Fantastic. And you see that we
2:25:45have a style sync created using this
2:25:47file name is this size in bytes is 45
2:25:49bytes. If you go here you have fs demo.
2:25:52This is what you have created. So now
2:25:54[snorts] you have this fs demo this
2:25:56folder right file system fs demo and
2:25:59then you have sync note text. And if you
2:26:01go here you have this created using sync
2:26:04uh fs and appended using sync fs. Okay.
2:26:07So this is how you're going to do what
2:26:09you're going to create folder and file
2:26:11synchronously. So this is one only one
2:26:13of the section. Now in the next section
2:26:14we are going to understand using call
2:26:16back and promises. See promises one is
2:26:18more important. So let's see how we
2:26:19going to do that in the next part. All
2:26:21right. So now let's understand how we
2:26:23can use call back based APIs. Right? So
2:26:25here first of all we need to know I
2:26:26think this pattern you remember that we
2:26:28have call back and in the call back we
2:26:30usually have error or the result. Right?
2:26:33So now let's create the function and we
2:26:35understand practically. So I'm just
2:26:36going to do run call back example
2:26:40here. This will be returning a promise
2:26:43and here I'm just going to return a file
2:26:46result also. Let's go to the top and
2:26:49create two more here. So one will be
2:26:51callback
2:26:53file path and also one will be the
2:26:55promise file path. So for this one let's
2:26:59keep this one as callback note and this
2:27:02will be my promise note. Okay.
2:27:06So first of all what we're going to do
2:27:07right so for this one we are going to
2:27:09wrap this call back example in a promise
2:27:12so that we can actually run this from
2:27:14this our runner okay from this main
2:27:16function but inside we are actually
2:27:18going to use our callback style APIs
2:27:20only. So first what we going to do right
2:27:22so first let's I'm just going to return
2:27:24a new promise and here I'll do a resolve
2:27:28reject.
2:27:30So now let's understand what actually we
2:27:32are doing here. So first of all uh just
2:27:34like we have uh understood that we have
2:27:36something called fs.right file sync
2:27:39correct for synchronous APIs. So what we
2:27:41need to use? So here we are going to use
2:27:43something called a do.t write file only.
2:27:46Okay. So here now we are going to pass
2:27:48our path. So our path will be our
2:27:51callback file path. And here uh sorry
2:27:55and uh call back uh file path comma
2:28:00let's do created
2:28:03using call back fs and we are going to
2:28:08pass our type which will be UTF8.
2:28:11Okay. So now here what we are going to
2:28:13do right you getting error. Okay. So
2:28:16first of all let's take the call back
2:28:18here. So we going to take the uh call
2:28:20back. So first I'm just going to do here
2:28:22write error.
2:28:27Okay. And then inside this first we need
2:28:30to understand that if we have error so
2:28:31we are going to reject the error. Right.
2:28:33So we are going to simply do if we have
2:28:35write error we're going to do reject. We
2:28:38are going to pass the error and then we
2:28:40are going to return. Okay. So this is
2:28:43the first thing that we are going to do.
2:28:45So this is about how we are going to
2:28:46write. Okay. So now what I have to do
2:28:50right uh also let's do one thing I think
2:28:52this will be 1 minute I think we are
2:28:55closing this one here
2:28:57after this okay here we are going to do
2:28:59append
2:29:01same only instead of append file sync
2:29:04you're going to use append file and then
2:29:06again you're going to I don't like this
2:29:08popup very limiting okay so here we are
2:29:11going to use this and then I'm simply
2:29:13going to do append
2:29:15using call back fs give space and then
2:29:20you're going to give the type which will
2:29:21be UTF
2:29:248
2:29:26that's it and then again also you're
2:29:28going to take another call back right so
2:29:30here you are going to have the call back
2:29:31so here we are going to do if there is
2:29:33any append error
2:29:36and then inside this we're going to
2:29:37again check if there is append error so
2:29:40we're going to reject the error and
2:29:41you'll see that this is actually what we
2:29:43call about call back hell because you
2:29:46are actually writing call back after
2:29:47call back Okay. And this will be return.
2:29:50So this about your append inside this
2:29:52again we are going to now read the file
2:29:54information. Right. So just like we have
2:29:56done uh write append read. So similarly
2:30:00here also now we're going to do fs dot
2:30:02read file not sync read file only. Here
2:30:05also you're going to pass callback file
2:30:07path and then we're going to pass the
2:30:10type which will be UTF8. And then what
2:30:12this is going to give? So here we are
2:30:13going to give uh so first of all we
2:30:16going to get the error. So let's take
2:30:18read error or else we're going to get
2:30:20the result which will be content the
2:30:23actual file content and then inside this
2:30:26we're going to again check if we have
2:30:27read error we're going to reject
2:30:31read error and then we're going to
2:30:33return okay and now what we can do right
2:30:36so inside this again we have to read the
2:30:39stat so simply if I just go here you can
2:30:41see that we are using a method inside
2:30:45call back first we are checking we are
2:30:46writing another call back inside that we
2:30:48are writing another call back. Now here
2:30:50we need to write another call back. Why
2:30:51we need to read the stat. So we going to
2:30:53use not stat sync but instead we going
2:30:56to use stat and here we're going to pass
2:30:58the call back file path and then this is
2:31:01going to give you either error. So I'm
2:31:02just going to do stat error
2:31:05and or else this will be stats array
2:31:10this popup man. So and then we are going
2:31:14to simply check if this stat error is
2:31:15present. We are going to reject
2:31:18the stat error or else and then we are
2:31:20going to return and at the end now we
2:31:23have to return the result but you can't
2:31:25return the result directly. You have to
2:31:27resolve it. So you are going to resolve
2:31:29it. So you're going to pass a style. So
2:31:31this will be your call back. You're
2:31:33going to pass the content. This content
2:31:36will be your uh this content will be we
2:31:38have created the content this content.
2:31:40Okay. This content that you have. Then
2:31:42you're going to pass the size in bytes.
2:31:44So size and bytes will be your stats and
2:31:46this stats is going to give you size and
2:31:50also you're going to have the file name.
2:31:52File name will be your path dot base
2:31:55name and you're going to pass a call
2:31:57file path. That's it. So this is done.
2:31:59Now you'll see if you go here and you
2:32:01notice that we are writing fs dot this
2:32:03is one our method right and inside call
2:32:07back. So inside this call back we have
2:32:09everything inside this we have append
2:32:11file inside append file call back we are
2:32:14having the read file inside read file we
2:32:16are having the stat and at the end we
2:32:18are resolving the result so this is a
2:32:20classic example of call back help so
2:32:22you're using call back after call back
2:32:24after call back like this and then what
2:32:26you can do right you can just do con and
2:32:28I'll do call back result so this will be
2:32:32a so I'll do call back what is the name
2:32:34we going to run call back example and
2:32:37then we're going to pass it here.
2:32:40Save this and let's run it.
2:32:44Enter. And you can see that. Fantastic.
2:32:46So now inside FS demo we have another.
2:32:49So now this time you're getting call
2:32:51back created using callback size by is
2:32:5451. And this is the file name because
2:32:56this is the file name we have created.
2:32:58Correct. So scroll down and let's go
2:33:00here. You can see that created using
2:33:01callback file system. So this will be a
2:33:04classic example of how you can implement
2:33:06using callback. Okay. So with this now
2:33:08let's move to the next one which will be
2:33:10how you can work with promises. This is
2:33:11exactly what you usually will be doing
2:33:14in your project. So let's do this one in
2:33:16the next part. Okay. So now let's create
2:33:18using promises, right? Promises one. Uh
2:33:20so first of all how we going to use
2:33:21promises? So we have we need to import
2:33:23something right. So we going to import
2:33:25fs promises
2:33:27from. So we have this module right? So
2:33:29we have mode file system / promises. So
2:33:32this is what we going to use. Okay. And
2:33:34this is much more easier and you'll
2:33:36understand what actually we are doing
2:33:37here. So let's do the promise API right.
2:33:40So here I'm simply going to uh take
2:33:42async. So I'll do function and this will
2:33:45be run promise
2:33:47example.
2:33:50What this is going to return again
2:33:51promise and the type will be file
2:33:54result. So first what we going to do? So
2:33:57first we need to write right. So to
2:34:00write we are going to use fs promises
2:34:02and this is going to give you this write
2:34:03file method. Okay. So this is where we
2:34:06are going to use our promise file path
2:34:10comma. So I'm just going to do this one
2:34:11as created using promise APIs. See again
2:34:16at the end it is the same thing right
2:34:18whatever we are doing. So this is going
2:34:19to write same way we are going to have.
2:34:23So we'll copy this and then we'll paste
2:34:25it here. You're going to have append
2:34:26file. So this will be appended using
2:34:29promise APIs. Okay.
2:34:33And then you're going to have the
2:34:35content. So to get the content remember
2:34:38content is the file content, right? So
2:34:40we going to do a so. So you have fs
2:34:41promises dot read file
2:34:46pass the promise file path
2:34:49and we are going to tell okay we are
2:34:50using text and similarly we're going to
2:34:52use stats. I'm not explaining because
2:34:54it's repeating. So you're going to do fs
2:34:56promises dot stats
2:34:59not stat uh this will be stat not stats
2:35:02and path and then we are going to
2:35:04return. So this will be style. So this
2:35:06will be promises right? So we're using
2:35:08promises. Uh then we have the content.
2:35:12Then file name. So this will be your
2:35:14path dot base name. This will be the
2:35:17promise file path. And then you're going
2:35:19to do size in bytes which will be stats
2:35:22dot size. That's it. And now we are
2:35:26going to simply use this in our uh here.
2:35:28So I'll do con.
2:35:31Let's do promise result.
2:35:34And this will be run promise example.
2:35:37And we're going to just log it here.
2:35:40The only difference is you are importing
2:35:42this one from file system promises
2:35:44module. And then if I just run it here.
2:35:46So we're going to get promises and one
2:35:48mode will be created, right? So if you
2:35:51go here sorry if you go here created
2:35:53using promise APIs appended using
2:35:55promise APIs. So I think this is going
2:35:58to give a proper understanding of how
2:35:59you can work with file system. How you
2:36:01can create file folder how you can check
2:36:03if that is exist or not. How you can
2:36:05create path and very very important how
2:36:07you're going to make use of both path
2:36:10module and file system together to
2:36:12implement this. Okay this is very
2:36:14important because consider you don't
2:36:15know that what is path.base name. So you
2:36:18will not be able to use right. So that
2:36:19is the reason we've discussed the path
2:36:21module previously and then we discuss
2:36:23the file system uh module. Okay. So with
2:36:27this now let's move on to the next
2:36:29module which will be another very
2:36:30important module and this will be
2:36:32buffers. Okay. So we will create one
2:36:34more file here. So I'm just going to do
2:36:36buffers.ts.
2:36:38Okay. Now this is another important. So
2:36:41first of all you need to understand that
2:36:42what actually buffers are and why we
2:36:44need buffers. Right. So first you
2:36:46whenever you need to work with raw
2:36:49binary data raw binary data and that
2:36:54that is where you are going to use
2:36:55buffers right now what actually binary
2:36:58data means now I'm not sure if some of
2:37:00you know means see binary data means
2:37:02when you have your data stored in bytes
2:37:06so your binary data means
2:37:09when you have
2:37:11your data stored in bytes as simple as
2:37:15that Right? Now you need to understand
2:37:17that when uh in JavaScript, right?
2:37:19Whenever you use something called
2:37:21strings, now these strings are good for
2:37:24normal text. But when you work with
2:37:26bytes or especially raw bytes, this is
2:37:29where you can't use strings that much.
2:37:31So you need to use something called
2:37:32buffers. Now one of the most important
2:37:34interview questions can be that where
2:37:37where all the places okay that you can
2:37:39use buffers. So first of all, one will
2:37:41be reading files. very important uh
2:37:45receiving very like there can be believe
2:37:48me or not there can be lot of
2:37:50complicated and very advanced level of
2:37:52places where you can or you need to use
2:37:54buffers okay so don't take this
2:37:56particular module lightly this is a very
2:37:58important module so when you're going to
2:38:01receive HTTP request bodies then also
2:38:03you can use buffers okay working with
2:38:06streams very very important you'll see
2:38:08that whenever you're going to work with
2:38:09streams right you are going to use or
2:38:10you need buffers uh
2:38:13handling images, PDFs, files uh and
2:38:18videos there also you need buffers also
2:38:21sometime you need to use encrypt and
2:38:23maybe let's say hashing then also you
2:38:25need buffers so these all will be very
2:38:28very frequently you are going to use
2:38:29buffers so first see if I I'm going to
2:38:32repeat one thing that what actually
2:38:34buffers and when you need to use buffer
2:38:37so first we need to mention that okay
2:38:38buffer we are going to use whenever we
2:38:40need to work with raw binary data data.
2:38:43Okay, raw binary data and raw why
2:38:45because JavaScript so they can ask okay
2:38:47why not JavaScript uh strings because
2:38:50strings are actually good only for
2:38:52normal text when you need to use raw
2:38:55binary data the binary data that is
2:38:58stored in bytes this is where you need
2:39:00buffers okay so just like this you have
2:39:03string so string means your human
2:39:06readable text then you have buffer means
2:39:11your raw byes
2:39:13like this. Okay. Now, first of all, you
2:39:15need to know how you can create normal
2:39:17or simple buffer. So, we have something
2:39:19called buffer dot from method. So, what
2:39:22you can do right, you can simply do
2:39:23let's I'm just going to create a text
2:39:25buffer. So, I'll do con text buffer. So,
2:39:28I I'll directly use buffer
2:39:31dot from and see that if I just go here,
2:39:34this has crazy amount of method. Okay,
2:39:36there is no way I can cover each and
2:39:38everything. But I'll try to cover only
2:39:40the best one. For example, how you can
2:39:42create buffer. So we give a buffer dot
2:39:44from and let's say I wanted to pass a
2:39:47text here. So this would be my text node
2:39:49something like this, right? So this is
2:39:51going to do what? This is going to
2:39:53create a buffer from a normal text
2:39:56because this is a text correct. So what
2:39:59will happen? This buff uh sorry this
2:40:02normal text will become bytes internally
2:40:06you're getting. So this is where we need
2:40:08or we are creating buffer from a normal
2:40:10text. Now consider if I'm just going to
2:40:12log this text buffer what will happen?
2:40:15So if you log this text buffer you are
2:40:18going to see
2:40:20can you guess? So you're going to see
2:40:22bytes and this will be hexa decimal
2:40:25format. Okay. So this is also very
2:40:26important. So let's test it. So I'm just
2:40:28going to save it and let's go to
2:40:30package.json JSON.
2:40:33So 08
2:40:35and I'll do tsx source/. So we have 08
2:40:39buffers.
2:40:41TS save.
2:40:45And then if I do clear and let's run
2:40:47again and you can see that you're
2:40:49getting buffer and this is you're
2:40:51getting actually this is not normal text
2:40:53right you can clearly see it. So this is
2:40:55simply bytes in hexadimal format. Okay.
2:40:59What will happen? Each uh value is one
2:41:01by. So here each value is one by. So n
2:41:06is actually uh sorry n is actually this
2:41:094 e right you are seeing here. Then you
2:41:12have o equal to this 6f then you have
2:41:16what is node n o d right? So d is
2:41:20becoming 64 like this right? So this is
2:41:23how you can create buffer. So now let's
2:41:25say what I need to do right I wanted to
2:41:28convert this particular raw buffer into
2:41:30my readable text only. So you have
2:41:32something called two string method and
2:41:34this two string method is going to
2:41:35convert that bite into the normal text.
2:41:37So for example
2:41:40uh if I go here and let's say I'll do
2:41:42log and I'm just going to do text buffer
2:41:46dot to string another very important and
2:41:48here you have to give the the type I
2:41:50think we already explained UTF- 8. So
2:41:53node you'll understand we are actually
2:41:54working with normal text or we are
2:41:56converting something to a normal text
2:41:58and if I just enter here you can see
2:42:00that you're getting node back right
2:42:01makes sense. So that means technically
2:42:04this text buffer whatever you have
2:42:06created from this and this particular
2:42:08line both are same. So this is in
2:42:10readable view and not readable uh
2:42:12readable means readable view only means
2:42:14we can human readable view and this is
2:42:17in buffer in bytes. Okay. So these are
2:42:20one of the most important two concept.
2:42:22Now let's understand some more uh
2:42:24important methods that mostly we're
2:42:26going to use. So something called buffer
2:42:28length. So now let's I'm just going to
2:42:30do here. So let's take a uh English
2:42:32buffer. I'm just going to give any
2:42:34random name whatever. So do buffer dot
2:42:37from and maybe I'll do hello. Okay. And
2:42:41now what I can do right I can simply
2:42:43just do here English buffer.length.
2:42:46And this is going to give you the length
2:42:47here. So save this. And if I just run
2:42:50this here. So we're going to get five.
2:42:53Okay. Also uh here what actually five
2:42:57means? So hello we have what? Five
2:42:59characters. Correct. 1 2 3 4 5. Five
2:43:02characters equal to five bytes. Okay. So
2:43:05this will be your buff uh buffer.length.
2:43:08So now you can also use another very
2:43:10important method that is called
2:43:12buffer.alloc.
2:43:13This buffer.alloc is going to do what?
2:43:15It's going to create a buffer with a
2:43:17fixed number of bytes. Very important.
2:43:19So what I'm talking about? also have
2:43:21something called allocation. So in short
2:43:24it's called alloc. So it's simply
2:43:26allocation like this. So it's like con
2:43:28I'm just going to do a fixed buffer. So
2:43:30do fixed buffer.
2:43:32So do buffer dot alloc alloc and then uh
2:43:37you're going to pass let's say five. So
2:43:39this is going to create a fixed number
2:43:40of buffer. So here if I just log this
2:43:44and let's say I'm just going to do empty
2:43:45fixed empty fixed. This is empty buffer
2:43:48but fixed buffer and this will be fixed
2:43:51buffer here and if you just log it right
2:43:53see what you're getting.
2:43:57So you can see that it's going to create
2:43:58empty buffer but it's going to create
2:44:00fixed buffer means we have given five.
2:44:02So it's going to create five.
2:44:05Now what you can do right we have
2:44:06another important see I already
2:44:07mentioned whatever methods that I have
2:44:09actually decided to cover. Remember
2:44:11there is a reason I'm not doing all of
2:44:13this blindly because you'll see whenever
2:44:15you're going to work in a project mostly
2:44:17you're going to use all of these only.
2:44:18So buffer from buffer uh uh that buffer
2:44:22dot to string buffer dot uh length
2:44:25buffer dotalloc all of this and then we
2:44:27have something called write. What write
2:44:30is going to do? So what you can do right
2:44:31you can write text into a existing
2:44:33buffer also. Okay. Now consider what we
2:44:36can do right. This fixed buffer is
2:44:39currently having what five bytes. And
2:44:42now what we are going to do right I'm
2:44:43going to add let's say three more bytes.
2:44:45So what I can do right I can take this
2:44:47fixed buffer and I can do something like
2:44:49write and this right is going to I'm
2:44:51just going to add API or whatever you're
2:44:53going to give. So what will happen this
2:44:55API actually need three bytes. Okay. So
2:44:57it's going to fit you're getting what
2:44:59I'm talking about and the remaining
2:45:00bytes because it has already has five.
2:45:02the remaining bytes will remain zero.
2:45:04It's very important. So what we are
2:45:06simply doing, I'm going to repeat once
2:45:07again. So we created fixed buffer of
2:45:09five bytes, right? All are empty, right?
2:45:12And now we are writing this API into
2:45:14this buffer. Fixed buffer. So this is
2:45:17going to take three bytes and this has
2:45:18five. So two will remain empty. So now
2:45:21if I just log here. So let's do fixed
2:45:24buffer.
2:45:27Fixed buffer up right.
2:45:31And I'm simply going to do fixed buffer.
2:45:36And I'll do log. And let's do fixed
2:45:39buffer.
2:45:41I'll do fixed buffer as text. So how we
2:45:46going to do text? So do fixed buffer dot
2:45:48two string.
2:45:50And then we're going to use UTF. Right?
2:45:53Save this and we'll see what is
2:45:55happening. Right?
2:46:00So you see we have see first one is
2:46:03empty fixed buffer after right is three
2:46:05because API is going to take three bytes
2:46:06and rest two will remain empty and then
2:46:09this is our fixed buffer as text is API
2:46:11okay fantastic so that means this is how
2:46:13you're going to do this also you can do
2:46:16something like this you can use let's
2:46:18discuss buffer concat method also
2:46:20because what will happen right so
2:46:22whenever you're going to work let's say
2:46:23you're working in a real project and
2:46:25you're getting data in chunks because
2:46:27that is possible that when your data is
2:46:29huge you are not going to get the data
2:46:31at once. So what will happen? You're
2:46:33going to get in chunks. So this will
2:46:35called as chunk. Chunk one, chunk two
2:46:37like this. What you can do right you can
2:46:39actually
2:46:40uh combine all of these into one buffer.
2:46:42So let's say I'm just going to get
2:46:44chunks. So I'm going to getting three
2:46:46chunks right. So how how I'm getting? So
2:46:48I have a buffer dot from. So this is my
2:46:51first chunk and this is hello. Then I'm
2:46:54going to give comma and I'm getting my
2:46:56second chunk. So I do buffer. And I'll
2:46:58do hello node.
2:47:00And then I'm just going to do buffer dot
2:47:03from and I'm just going to do hello
2:47:05nodejs something like so I have three
2:47:07chunks. What I can do right I can
2:47:09combine all of these into one. So I do
2:47:11combine buffer
2:47:14and this will be chunks not chunk what
2:47:17I'm doing. So buffer doconet
2:47:20and you're going to use this chunks. So
2:47:22what this is going to do this is going
2:47:24to combine all of this into one and then
2:47:27you're going to simply log this. If I
2:47:29just do log here, combine buffer and
2:47:32also let's do combine buffer.2 string
2:47:35and I'm just going to do UTF8. So you'll
2:47:37understand clearly what is happening
2:47:39here. So let's log this [screaming]
2:47:42and you can see that what you're
2:47:44getting. So you're getting hello NodeJS
2:47:46and this is the combined buffer. So
2:47:47you're getting hello NodeJS. Makes
2:47:49sense, right? So that means this
2:47:51actually combined and created one
2:47:53buffer. Okay. So I think this is done.
2:47:56uh also I think I think this should be
2:47:58enough right so what we have covered so
2:48:00far so covered that buffer is going to
2:48:01store raw bytes buffer from is going to
2:48:04create buffer from data buffer tworing
2:48:07is going to convert your text from your
2:48:09buffer bufferlength is going to give you
2:48:12the length buffer allocation is going to
2:48:14do what it's going to create empty
2:48:15buffer buffer write is going to write
2:48:19your data into a buffer and buffer
2:48:21concat is going to combine multiple
2:48:23buffer chunks believe me if you can
2:48:25master all of this right most of the
2:48:27time you'll be able to work with buffers
2:48:29okay so with this now let's move on to
2:48:31the next one all right so moving to the
2:48:33next one so let's create and normally
2:48:36other videos I'm not sure I think they
2:48:38usually not cover this but but I'm going
2:48:40to cover this one okay this is another
2:48:41important one and this will be URL
2:48:43module okay so let's see in the next
2:48:46part we going to have the HTTP module
2:48:48right and there it will be actually
2:48:49helpful and also when we are going to
2:48:51actually implement our APIs and
2:48:52everything so what we're going to do
2:48:54right So this URL module is going to
2:48:57help you to work with URLs uh safely
2:49:00something like that. Okay. So because
2:49:02see what will happen whenever you're
2:49:04going to do any back end development
2:49:05maybe you need some protocol information
2:49:07or you need which host name you're using
2:49:09or maybe you need the path or maybe you
2:49:11need the query parameters mostly query
2:49:13parameters and all you are going to use
2:49:15a lot. So consider maybe I'm just going
2:49:18to take this example right. So I'm just
2:49:19going to do HTTP
2:49:21HTTPS. Let's take API.ample example.com
2:49:25whatever you want to take.example.com
2:49:27example.com then I have / users and then
2:49:29here I'm going to have let's I'm going
2:49:30to use a paginess and page two and then
2:49:33I'm using limit will be 20 or 10
2:49:35whatever you wanted to take right so in
2:49:36this case what will be your path name
2:49:38your path name is this one so/ user page
2:49:41is actually two and limit is 10 which is
2:49:43what this is your query patterns that
2:49:44you are actually doing right so let's uh
2:49:47implement this one in a simpler way so
2:49:48what I'm going to do right I'm going to
2:49:50take a function and then I'm just going
2:49:52to do run url demo uh let's return void
2:49:56only we going to return and things will
2:49:57do void and then I'm simply going to do
2:49:59con API URL. So how we are going to do
2:50:02here? We are going to create a API sorry
2:50:04we are going to create a not API man we
2:50:06are going to create a URL object. How
2:50:08you going to create a URL object? So the
2:50:10question is how you can create how to
2:50:12create
2:50:14URL object from URL string. Now this is
2:50:18very important. Okay you need to know
2:50:20all of this. You see that in most
2:50:21project we usually use this. we have to
2:50:24do new URL and here you have to pass the
2:50:27uh string. So for example let's I'm just
2:50:29going to take https colon and I'm do
2:50:32let's say apias devob I'm just going to
2:50:35take a debub as example and here I'm
2:50:37just going to do user information I'm
2:50:39getting and here I'll do page equal to
2:50:41two and then let's say let's take a
2:50:44limit the limit will be 10 and also I'm
2:50:46just going to take a sort sort will be
2:50:48latest something like this
2:50:52okay so now what I'm doing don't need
2:50:55this okay so now what we going to do
2:50:57Right. Oh, I think it was correct only.
2:51:00So here I thought I've taken this one in
2:51:02middle. So here I'm just going to log
2:51:03couple of things. Okay. So I'll do log
2:51:06and let's do full URL. So how you are
2:51:08going to get the full URL. So you have
2:51:10to do something like this. So do API
2:51:11URL. Here. So this is going to give you
2:51:14the full URL. Okay. And [snorts] before
2:51:16that also let's do one thing. We are
2:51:18going to run this. Okay. So I'm just
2:51:20going to run this here. So I'll do run
2:51:22URL demo. Save this. Uh let's copy this.
2:51:26go to package dojson and here I'll do 09
2:51:31and I'll do tsx source/ this
2:51:36and let's run one by one. So I'll do 09
2:51:40and I'll see that you're going to get
2:51:41the full URL. Okay, so this is going to
2:51:43give you the full URL. Now what I have
2:51:45to get right so a couple of things I
2:51:47need to get. So I need to get the
2:51:48protocol. So you can do API URL
2:51:50dotprotocol.
2:51:52You're going to get API URL dot host
2:51:55name. This is going to give you the host
2:51:56name. You're going to get the path name
2:51:58API URL.path name and very very
2:52:02important you are also going to get your
2:52:04search uh string or query string. How?
2:52:07So you'll do AP URL dot search. And if
2:52:10you save all of these and let's run all
2:52:12of these and see what you're getting.
2:52:18Okay. So you're getting this. This is
2:52:20the https your protocol. Then you're
2:52:22going to have your host name
2:52:23api.hdep.com. debugab.com this is your
2:52:25path name and this is your search or
2:52:27query string right and this is your
2:52:29complete one complete means your href so
2:52:32this all the information you're going to
2:52:34get now what actually search param
2:52:36usually do right so there is a method
2:52:38method called search panam one of the
2:52:40most important concept that you need to
2:52:42know whenever you'll be working with
2:52:43mostly you are going to work with filter
2:52:45search sort all these things okay so
2:52:48what is search pam so search param is
2:52:51going to give you the capacity to read
2:52:53query parameters. Okay, so query
2:52:55parameters means where it will start
2:52:58with normally with this. So you have
2:52:59your uh URL and then you have something
2:53:01starting with this question mark and
2:53:03after right side whatever you're going
2:53:04to have usually you'll call this one as
2:53:06query parameters. Okay. So now let's say
2:53:09I wanted to get my page information. So
2:53:11what I can do right I will do API URL
2:53:14and this is going to give me my search
2:53:15params and this search param is going to
2:53:17give you this. See we have get append
2:53:19delete entries blah blah lot of things
2:53:21you're going to get get because I need
2:53:23to get the information of page. So this
2:53:25will be your key and this will be your
2:53:27value. So my page is the key value is
2:53:29will be two. Limit is key. 10 is value.
2:53:32Sort is key. Latest is value. So here I
2:53:34wanted to get page. So I'll do page
2:53:36here. So this is going to give me page
2:53:38information. Copy this. And now let's
2:53:40say I wanted to get my limit.
2:53:43So this will be my limit.
2:53:46And also I'm just going to get a sort.
2:53:48This will be my sort. And then if I just
2:53:50log all of this and you're going to get
2:53:52page
2:53:54limit and sort, right? You save all of
2:53:57these. For now, I'll comment it out.
2:53:59This one here
2:54:02and then run it. So you're going to get
2:54:042 10 and latest. So you're getting 2 10
2:54:07and latest. So this is where you're
2:54:09going to use called search params. Okay.
2:54:12You can also update the search params.
2:54:15how you're going to update. So let's I
2:54:16wanted to update my page from two from
2:54:19two to three, right? I can do that. So
2:54:22I'll do API URL dot search param and
2:54:24then you're going to do set and set is
2:54:26will be your key value. So key is your
2:54:28page value will be your let's say 10. So
2:54:32from uh this will be string. Okay. So
2:54:35this from two it will be changed to 10.
2:54:38Let's say you wanted to change your
2:54:39limit from 10 to 20. So I can do like
2:54:42this. So I'll do apurl searchparence dot
2:54:45set and this will be what is that limit
2:54:48limit will be maybe 20. Okay. So now
2:54:52what I can do right I can just log it
2:54:54here. So I do log and I'll do apur.h
2:54:58and see what will happen. Okay. And if I
2:55:00just run it.
2:55:03So you see that previously you have 210
2:55:05latest. Now your page is 10 limit is 20.
2:55:08Sort is latest. Means using this set you
2:55:11will be able to update these values
2:55:13also. Okay. Now you have also another
2:55:16very very important something called URL
2:55:18search params. This also you can use
2:55:20separately. Now when this is very
2:55:22helpful let's say wanted to build some
2:55:24query string. So in that case URL search
2:55:27param is very very very important
2:55:29concept very important mean like too
2:55:31important because you are actually going
2:55:33to use this one in a real project. So
2:55:35how you can do this? So let's I wanted
2:55:36to create some query params. So I'll do
2:55:39new URL search params and this is where
2:55:42you can actually give let's say my
2:55:43search value is nodej
2:55:46my page is one and my limit is
2:55:52my limit is let's say five and now what
2:55:54I can do right I can simply log this so
2:55:57I do log and you can do query params and
2:56:00you can do two string
2:56:02query params dot two string okay so now
2:56:07let's save this And if I just log it
2:56:09here, you'll see that what you're going
2:56:10to get.
2:56:13See, you're getting search nodejs and
2:56:16page equal to 1 and limit equal to 5.
2:56:19That means this is going to create a
2:56:20search param which you can also append
2:56:22in your URL. Okay. So this is all the
2:56:25things that you are going to uh or you
2:56:28can use from your URL module. Okay. So
2:56:30these all are very important and
2:56:32whatever we have discussed in this
2:56:33particular module that actually you're
2:56:35going to use in a project. So with this
2:56:37now let's move on to the next one. Okay.
2:56:38So moving to the next one. So let's
2:56:40understand one more and this will be so
2:56:42we are going to understand event
2:56:44emitters. Okay. So let's do event
2:56:47emitter.ts.
2:56:49So first we'll understand that what
2:56:51actually event emitter is. Now event
2:56:53emitter will be or say event emitter
2:56:55you're going to use when let's say you
2:56:57have
2:56:59consider this one that you have one part
2:57:01of application that want to announce
2:57:02that something happened and other part
2:57:05of that application that part want to
2:57:07listen to that particular that okay this
2:57:09this is something happened and based on
2:57:11this I wanted to do something okay so
2:57:14simple example will be let's say uh you
2:57:17are implementing a functionality okay
2:57:19and the functionality is that user
2:57:20actually registered
2:57:22So once user will comes to your
2:57:24application they're going to give your
2:57:25email password or whatever right uh name
2:57:27blah blah once user registered so
2:57:30consider this one as a one part of your
2:57:32app so it's doing something right so
2:57:35once user will register after this we
2:57:38are going to do something okay so for
2:57:40example let's say there can be
2:57:42possibility that okay we have a feature
2:57:44that once user will register we need to
2:57:46send a welcome email correct or maybe
2:57:50let's say we need to write a log or
2:57:54maybe let's say we need to notify some
2:57:56other service some other service that
2:57:57you have
2:58:00okay notify some other service so now if
2:58:04you see that this is like a two-way
2:58:06thing is happening two-way in the sense
2:58:07means I'm trying to explain in a simpler
2:58:09way that you are doing something so this
2:58:11is what you're doing and based on that
2:58:13you want to do something so based on
2:58:15user registration you want to do some
2:58:17other activity okay so this is where we
2:58:20have something called event right so
2:58:22this is like event so it's like I'm not
2:58:25sure if you're familiar with Kafka so
2:58:27it's like a you have a producer so
2:58:29something is producing right something
2:58:32and that producer is sending that
2:58:35information to a uh mediator and then
2:58:38consumer is going to consume it so it's
2:58:40like this right so you have a producer
2:58:42consumer so consider like this so here
2:58:45what we have to do right so event
2:58:47emitter is going to let's say emit one
2:58:49particular event and listener what
2:58:52they're going to do? So listeners is
2:58:54going to handle that particular listener
2:58:56is going to listen to that event and
2:58:58based on this is going to do something.
2:59:00So for example, let's say here we have
2:59:02something like this. So event emitter is
2:59:04going to emit one event and then you
2:59:07have listeners. Listeners is going to
2:59:10listen to this event
2:59:13and then it's going to do something.
2:59:14It's going to do something based on
2:59:16this.
2:59:18So here we have some method that you
2:59:19need to know which are very important.
2:59:21So first one will be
2:59:24do on. So what this is going to do? So
2:59:26this is going to register
2:59:28one listener. So this is the first
2:59:30thing. Okay. So every time let's say
2:59:34there is a event and that event is
2:59:36emitted it's going to reg it's going to
2:59:39run and register one listener. Okay. So
2:59:41dot on method. Then you have something
2:59:44called dot once. Now this is also
2:59:47important. Now what this is going to do
2:59:48this is going to register a particular
2:59:50listener. So this is also register one
2:59:52listener but the difference is it's
2:59:54going to run only once. That run that
2:59:57runs only one time. Okay. And then you
3:00:02have something called dot emit. So dot
3:00:04emit is going to do what? It's going to
3:00:06triggers an event and it's going to send
3:00:10that event to the listeners.
3:00:13So mostly you need to master all these
3:00:15three things. Okay. So first of all
3:00:17let's say we will create uh so let's
3:00:19take con and I'll do app events. Maybe
3:00:22let's do app events only and then I'm
3:00:24simply going to do new and here I'm just
3:00:26going to do event emitter. This event
3:00:28emitter you're going to import from node
3:00:31events. Okay. So this will be from node
3:00:34colon events and this event emitter. So
3:00:37this will be your event emitter. Right.
3:00:39So here now what we going to do right?
3:00:41So let's say we are let's take this
3:00:44example only user registration. So I'm
3:00:46just going to take one type and I'll do
3:00:49user register payload
3:00:54and here we're going to have a num ID
3:00:56which will be number and also we're
3:00:58going to have a email which will be
3:01:00string. Okay.
3:01:03Now what I'm going to do right so here
3:01:05let's say I have a listener one first
3:01:07listener. So when this listener will run
3:01:10whatever we are going to write. So
3:01:11whenever let's say we have a event and
3:01:14that event is going to do something. So
3:01:16whenever user will register we are going
3:01:18to emit one particular event and once
3:01:20we're going to emit that event listener
3:01:23is going to listen to that particular
3:01:25event and listener is going to run.
3:01:27Okay. So in this case in real example
3:01:29will be once you'll see that once you
3:01:31register any particular website you'll
3:01:33see that you are going to get some
3:01:35welcome email. Correct. So it's
3:01:36something like this. So here what I'm
3:01:38going to do right so I will be having so
3:01:40I'm just going to app events do on and
3:01:43here I'm going to pass a event name this
3:01:45event name will be once user will
3:01:48register so this is my event name
3:01:50consider okay user registered and once
3:01:53user will register so whenever this
3:01:55particular we are going to emit this
3:01:58particular event we are going to pass
3:01:59some event okay sorry pass some payload
3:02:01and that payload we are going to receive
3:02:03here but before doing this what we going
3:02:05to do like maybe let's say uh what I'm
3:02:08going to do right let's keep it like
3:02:09this okay I'm just going to create one
3:02:12function and let's do register user so
3:02:15this is my actual function where you're
3:02:17going to do something so here for now
3:02:19I'm just going to give void and I'll do
3:02:21con user and user is going to have ID
3:02:24one and let's do user is going to have a
3:02:26email and I'll take my email here
3:02:28whatever you want to take now what I'm
3:02:30going to do right so first of all I'm
3:02:32just going to do log and I'll do user
3:02:34saved so in n in actual application what
3:02:36you're going to do you're going to do
3:02:37some DB operation and you are going to
3:02:39save the user to your DB something like
3:02:41this correct and now this is where you
3:02:43are going to emit the event see remember
3:02:45you need to emit so once you emit the
3:02:47event your listener is going to listen
3:02:49to that event so here I'm just going to
3:02:51do app events do emit and here we are
3:02:53going to give the event name okay now
3:02:55remember whatever you're emitting the
3:02:57event name and the listener event name
3:02:59should remain same so here we are
3:03:02actually emitting uh that okay user is
3:03:04now registered And then we are going to
3:03:06pass a user payload. So this will be my
3:03:09payload or this will be my data this
3:03:11particular event emitter uh event
3:03:12emitter is emitting correct. [snorts] So
3:03:15now what will happen when I'm going to
3:03:16listen to this particular event this
3:03:19data whatever I'm sending here this
3:03:22listener will be able to access and
3:03:24based on this you can do whatever you
3:03:25want. For example let's say wanted to
3:03:26send a welcome email you can do this
3:03:28right. For example, in this user, you
3:03:31have the email information. So, we'll be
3:03:32able to send that uh email to that
3:03:34particular user. So, this is how it will
3:03:36work. So, now what you can do, right?
3:03:38When this listener is going to listen,
3:03:40it will actually match this particular
3:03:42event, whatever event we have. And now,
3:03:45this is where we are going to get our
3:03:46payload. So, here I'm just going to do
3:03:48us a register payload.
3:03:51And here what we can do can let's say
3:03:52I'm just going to log here and I'm just
3:03:54going to do email
3:03:57listener
3:03:59and this email listener is going to do
3:04:01let's I'm just going to do a welcome
3:04:02email send to
3:04:05this user
3:04:08and here you're going to pass user do
3:04:10email okay so this is going to do that
3:04:13now what you can do right this is a very
3:04:15important concept that you can have
3:04:17multiple listener for the same event
3:04:19okay so let's say you wanted to create
3:04:21one more listener here. Okay. So maybe
3:04:23I'm just going to do app events do on
3:04:26and I'm going to give same uh event name
3:04:28user register.
3:04:32Okay. And then let's say I'm just going
3:04:34to take the same thing. So I'll do user
3:04:36will be user uh payload. And this is
3:04:39where I'm simply going to do what maybe
3:04:41let's say I'm just going to log event
3:04:43right. So something like this. And here
3:04:45I'm just going to do log listener. And
3:04:48then I'm just going to do user. Username
3:04:50is user do ID and email is and here I'm
3:04:55just going to do user do email. Okay. So
3:04:58that means you can do what right? You
3:05:00can actually register multiple listener
3:05:02for the same event also. Okay. So this
3:05:06is the first thing that we need to
3:05:07understand. Now also let's do one thing.
3:05:09After this what we can do right? I'm
3:05:10just going to do a log and I'm simply
3:05:13going to do register user. And here I'll
3:05:17do event listener sorry event listener
3:05:22completed something like this okay and
3:05:25now let's say first of all I'm just
3:05:27going to log this register user here and
3:05:29then we're going to understand one more
3:05:30concept but this is how it will work
3:05:32okay this is how actually in the project
3:05:35also we're going to implement so at the
3:05:37end it's going to emit event and on the
3:05:39other side the listener is going to
3:05:41listen to that event and it's going to
3:05:42do a real job okay so now let's go here
3:05:45I'm just going to copy this and I'll do
3:05:4810 ts source/ this and if I go here
3:05:56let's run this
3:05:59so user saved email listener welcome
3:06:01email sent to user sum log listener so
3:06:04that means you can see we emitate the
3:06:06event only once but we have a two
3:06:08listener so both listener will work okay
3:06:10and you have log listener and register
3:06:13user event listener completed so this is
3:06:15how it's going to work. So now we have
3:06:17one more concept and that is that how
3:06:18you can use once. Once means this one
3:06:21register one listener that run only one
3:06:23time. So now let's say what I can do
3:06:26right I can create one more here. So I
3:06:27do app events do on let's have one more
3:06:30event here and that is app dot start
3:06:32means once our app will start we wanted
3:06:34to do something. Okay and here I'm
3:06:38simply going to do log and let's do once
3:06:41listener. So I'll do once listener and
3:06:44now uh app
3:06:48app started let's move here. So app
3:06:51started something like this. So whenever
3:06:53our app will run that time I wanted to
3:06:55run this and now what I'm going to do
3:06:57right see notice if I go here and I'll
3:07:00do app events do emit
3:07:02and I have this app dot started this
3:07:05event.
3:07:07So I'm going to emit this and then I'm
3:07:09also going to emit this one more time.
3:07:12But what will happen right? Because we
3:07:13are using once even though we are
3:07:15emitting twice listener will be
3:07:18registered with only once because we
3:07:20have once here. Oh we need to do once
3:07:22here we need to do once. Okay. So this
3:07:24will be once. So it will only run first
3:07:26thing and if I go here let's run this
3:07:29again.
3:07:31So you see that once listener app
3:07:33started user saved email listener and
3:07:35all this. So this will be the uh concept
3:07:38of uh event listener that what actually
3:07:41event is the very important method how
3:07:43we are going to emit event and how
3:07:45listener is going to listen to that
3:07:46event. So with this now let's move on to
3:07:48the next one. So with the core modules I
3:07:50think we are almost at the end and now
3:07:52let's finish this particular section
3:07:54with so I'm just going to 11 and we are
3:07:56going to understand streams okay streams
3:07:58are also very important. So first of all
3:08:02you have to understand again as usual
3:08:03right that when you're going to use
3:08:05stream and why actually you need it. So
3:08:07first of all streams are used when the
3:08:09data uh you want to handle. So whatever
3:08:11data you're handling piece by piece.
3:08:14Okay. So you want to handle the data
3:08:15piece by piece. Okay. Now what I mean by
3:08:18this? So here what you're doing right
3:08:20you are not loading the data not loading
3:08:22the data not loading the data like
3:08:26everything at once. Everything
3:08:29at once. So this will be better way to
3:08:31put it. So you're not loading the data
3:08:32all at once. You are handling it piece
3:08:35by piece. Right? Now the best example of
3:08:38you uh stream using will be let's say
3:08:40you wanted to read some large files.
3:08:43Okay. Or you want to upload files. This
3:08:46is also very very important. This is
3:08:48where you can actually use streams.
3:08:50Okay. Or same will be downloading. So
3:08:52you want to download files. Let's say
3:08:54you're downloading very big files. So
3:08:56instead of downloading all at once,
3:08:57you're downloading piece by piece.
3:08:58Right? Some sometime you are also going
3:09:01to use let's say you're improving audio
3:09:02video uh processing that also you can
3:09:06use. Now see whatever this uh we are
3:09:09discussing that all these use cases are
3:09:10actually real and you are actually going
3:09:12to use this in projects also you need
3:09:14this one sometimes in compressions also.
3:09:18So this is will be where you're going to
3:09:20use uh streams. Okay. Now uh first of
3:09:23all what will happen right the main idea
3:09:25or the core concept of stream will be
3:09:27that stream doesn't give you the data
3:09:29immediately. So it's not going to give
3:09:30you the data immediately. It's going to
3:09:32give you the data is in small and we
3:09:35already know this particular term that
3:09:37we have discussed and that is called
3:09:39chunk. Right? So remember I already
3:09:41mentioned this one chunks. So here it's
3:09:43going to give you the data in small
3:09:45pieces that we call as chunks. Okay.
3:09:48So now how it's going to do? So let's
3:09:51say I have this that okay here is here
3:09:54is my full 500 MB file something like
3:09:59this stream what it's going to do it's
3:10:01going to do this okay so look here is
3:10:03chunk one
3:10:06then it's it will do here is chunk two 3
3:10:114 5 something like this okay so it's
3:10:14going to give you in chunk why now first
3:10:16of all one of the most advantage would
3:10:18be this will be memory efficient because
3:10:20you can Right? We are not handling all
3:10:22the data at once. So there will be not
3:10:25too much overloading on memory. Right?
3:10:26So this will be memory efficient. Okay.
3:10:29Now u also you also need to understand
3:10:32some of the stream types. Okay. I I
3:10:34forgot to mention this. So for example,
3:10:35let's say we have something called uh
3:10:38stream types. Stream types are actually
3:10:40important. So we have readable stream,
3:10:42right? So you have readable readable
3:10:44streams. I'm not sure if the spelling is
3:10:46wrong. If it is wrong, I think readable.
3:10:48Okay. So readable stream. Readable
3:10:50streams will be or readable stream will
3:10:52be like where you have some data. So you
3:10:54have some source of data something like
3:10:56this.
3:10:57Okay. Now here maybe let's say example
3:11:00will be uh what maybe HTTP request body
3:11:04or file you're going to read some data
3:11:06or read some data from a file big file
3:11:08right so this will be readable then you
3:11:11have something called writable stream.
3:11:14Writable stem will be like uh there will
3:11:16be some place or some uh I don't know
3:11:19the English term man okay uh destination
3:11:22so there will be some destination where
3:11:23you're going to data you want to write
3:11:25the data so there will be destination
3:11:28where the data where the data is written
3:11:32okay and then you have something called
3:11:35transform transform transform stream now
3:11:38this is also very important transform
3:11:40means it's kind of a stream that's going
3:11:42to read your data it's is going to
3:11:44change it also. Okay. And then very
3:11:47important, it's going to pass that
3:11:48stream to forward. So pass it forward.
3:11:50So it's going to read the data.
3:11:53Read the data if needed. It's going to
3:11:55change it. So it's going to change the
3:11:56data and then it's going to pass the
3:11:58data. Pass that pass that forward. Okay.
3:12:04So example will be let's say this one
3:12:06only. Compression will be a proper
3:12:07example for this, right? Or maybe let's
3:12:09say you want to the basic example. Let's
3:12:11say you wanted to convert your text to
3:12:13upper case. So we are going to see some
3:12:14example but from a definition wise
3:12:16right. So all these key points whatever
3:12:18I have explained are actually very
3:12:19important. So let's start with readable.
3:12:21Readable means I already mentioned. So
3:12:23there are some method you need to also
3:12:25understand. So let's create a readable
3:12:26stream. So I'm just going to do readable
3:12:29and I'll do string. Okay. What you're
3:12:31going to do right you're going to use
3:12:32something called readable. And this
3:12:34readable from where you're going to use
3:12:36this readable you're going to import
3:12:38from this node uh stream. So you can see
3:12:40that you have this one. So vable you're
3:12:42going to use from your stream package.
3:12:44So you have node colon stream.
3:12:47Okay. So what this is going to do right.
3:12:49So first of all let's create this. So
3:12:50I'm just going to readable and you have
3:12:52to use this form. So here what this is
3:12:55going to do this is going to create a
3:12:56readable string but it's going to create
3:12:58from an array. Each item that you're
3:13:00going to have in this particular array
3:13:02will become what will become chunks.
3:13:04Chunks are very important. Okay. So
3:13:06whatever array you are going to have is
3:13:08it will become chunks. How you're going
3:13:10to do this? So we're going to do like
3:13:11this. So every data let's have a hello
3:13:14give space uh space let's say maybe I'll
3:13:17do from let's do nodejs node js and I'm
3:13:22just going to do streams something like
3:13:24this right. So this will be readable
3:13:28stream. So very simple one. Now let's
3:13:31understand transform one. So what you're
3:13:33going to do right maybe let's uh take
3:13:35that example that we are going to
3:13:36convert some text to upper case. So what
3:13:38I'll do right I'm just going to create a
3:13:40const and I'll do uppercase
3:13:43transform.
3:13:46So here we're going to use something
3:13:48called new transform and this transform
3:13:50you're going to import from node stream
3:13:51only. So what this is going to do right.
3:13:54So here you are going to use a transform
3:13:56method. So you can see that you have a
3:13:57transform. Transform is going to take a
3:13:59chunk encoding and there will be a call
3:14:01back. Okay. Chunk. What is chunk? Chunk
3:14:04is usually buffer in the buffer concept
3:14:06we have discussed right. So chunk will
3:14:07be buffer. What we are going to do right
3:14:09here? Let's say we have some uh string
3:14:12and then we are going to convert that
3:14:14chunk to a string that also discussed
3:14:16that you can directly do chunk dot to
3:14:18string and based on that you can do
3:14:19certain operation and at the end what
3:14:21you can do you can pass that result to
3:14:23the call back. Call back format also you
3:14:25have discussed the classic callback
3:14:27format call back and then you're going
3:14:29to have error and then you're going to
3:14:30have result. You remember this part I
3:14:32discussed. So consider so here first of
3:14:34all let's take this one at transform. So
3:14:36in this transform this is going to take
3:14:38chunk this is also going to take the
3:14:41encoding and this is also going to take
3:14:43a callback which is very very important.
3:14:45Okay. So now let's say I wanted to do
3:14:47something here. So first of all I will
3:14:49be having a text and then I'm just going
3:14:51to do chunk dot twing.
3:14:54Okay. And here so let's take the call
3:14:58back. So error will be null and I'm just
3:15:00going to do so this is what I'm just
3:15:01going to do. Text dot two uppercase.
3:15:05So we're going to do text dot two
3:15:07uppercase. So what we are doing right we
3:15:09are actually sending this transform data
3:15:12this transform data where so it's going
3:15:14to send this data forward. Okay. Null
3:15:17means we don't have any error. Okay. And
3:15:19this result is nothing but it will be
3:15:21the new chunk that is going to move to
3:15:24the next string. Now I know that this
3:15:26might be little tricky but you need to
3:15:28understand all of this right that how
3:15:29readable uh transform and writable all
3:15:32these string works or that there is no
3:15:33point because these are very very basic
3:15:35concept. Now what we're going to do
3:15:37right now let's write one writable
3:15:39string. So writable string is going to
3:15:40do it's going to receive the chunk and
3:15:43then it's going to do something we don't
3:15:44know what is why because that is going
3:15:46to depend uh based on the project or
3:15:48based on the feature you are doing.
3:15:50Okay. So what this is going to do right
3:15:52simple way just remember or you can note
3:15:54it down writable is going to write data
3:15:56to a particular file or it's possible
3:15:59it's going to send data to HTTP server
3:16:01also or maybe let's say it's going to
3:16:02upload data to some cloud that is also
3:16:06possible. Okay. So now
3:16:09uh let's do writable stream. So how you
3:16:12can do write you are going to use
3:16:13something called writable. So you'll see
3:16:15that we have writable this one. Okay.
3:16:18And now here you're going to do
3:16:19something called write. See, write also
3:16:21is going to receive what? Chunk,
3:16:22encoding, call back. So, I'm just going
3:16:24to take right. So, I'll do chunk. Uh, we
3:16:27have the encoding and the call back. So,
3:16:29do encoding and the call back. So, first
3:16:33I'm just going to log something here and
3:16:35let's do received
3:16:38chunk and here I'm simply going to do
3:16:40chunk dot to string. So, this is the
3:16:44first thing. So, now what we're going to
3:16:46do right, we are simply going to call
3:16:48this callback. You have to understand
3:16:50till this time we have already discussed
3:16:52that multiple times what actually call
3:16:54back is but why we need this call back
3:16:56here. What this call back is going to
3:16:57do. So this call back is going to tell
3:16:59node that okay I already have handled
3:17:01this particular chunk. Now you can send
3:17:05this one to next one. Simple. Okay. So
3:17:08this means this call back is simply
3:17:10telling that okay I'm done with my job.
3:17:11Now you do the rest or move this one to
3:17:14next one. And now you are going to we
3:17:16are going to combine all of these to a
3:17:18certain not certain we are going to
3:17:20combine all these readable transform
3:17:22writable into one particular concept and
3:17:24that we call as pipeline. Now pipeline
3:17:27is very very important. What pipeline is
3:17:29going to do? Now you see that each and
3:17:30everything is individual right? So it's
3:17:32going to read something. It's going to
3:17:33create a readable stream. It's going to
3:17:35do some action here. It's going to uh
3:17:38convert this one text to upper case and
3:17:40it's going to write this data to some
3:17:41place whatever it is. But all these are
3:17:44independent. There is no connection. So
3:17:46that means what we're going to do? We
3:17:47need to use something that is called
3:17:48pipeline. Pipeline is going to connect
3:17:50all these stream together. Okay. So now
3:17:53we are going to create a uh let's do a
3:17:56function and I'm just going to do a main
3:17:58and here I'm just going to have a
3:18:00promise.
3:18:02Let's do void. So how this will work? So
3:18:05first of all we're going to take a try
3:18:06catch. So in the catch we're going to do
3:18:09error. So first let's handle the error.
3:18:11So we'll do the same thing. So I'll do
3:18:13message if this error is instance of
3:18:15error. So I'm going to do error dot
3:18:19message or else I'm just going to do
3:18:21unknown error.
3:18:24And here I'm just going to do
3:18:27stream
3:18:29failed and here I will do message.
3:18:33Okay. Now in the try so we going to use
3:18:36something called a and we going to use
3:18:38something called pipeline and this
3:18:39pipeline we are going to import from
3:18:41node string promises okay so from here
3:18:44we are going to import so from node
3:18:45streams has promises you're going to
3:18:47have so what this pipeline is going to
3:18:49do now this is actually very important
3:18:50concept okay and this can be if you know
3:18:52all this right and let's see if you can
3:18:54answer all of this in interview you'll
3:18:55be like okay your interview will be
3:18:57actually impressed okay if you know
3:18:59because these are pure node concept we
3:19:01are not using any framework or anything
3:19:03like Right pipeline is going to connect
3:19:05all your stream together. Okay. So we
3:19:08have first we have a readable string
3:19:10correct and then readable string we
3:19:12going to do what? We are going to upper
3:19:13case. So we going to convert that text
3:19:15to upper case and then we going to use
3:19:17the rightable. So now what you can do
3:19:19right you can actually directly pass all
3:19:21your source here. Source means you can
3:19:22pass your readable. Then I'm just going
3:19:25to do my uppercase. So this is my
3:19:28transform. So we are transforming
3:19:29something. We are doing some action and
3:19:30then we going to do a writable. That's
3:19:32it. And then what you can do, you can
3:19:34just do a log and this stream sorry do
3:19:38stream completed something like this.
3:19:41That's it. And then what you're going to
3:19:42do right, you're going to just uh not
3:19:45here outside. We're going to call this
3:19:47main.
3:19:49So save this.
3:19:51Now let's copy this. Go here.
3:19:57So we'll do tsx source/ this
3:20:03and let's do here. We'll see what you're
3:20:05getting. So you're getting received
3:20:06chunk hello from nodejs uh streams and
3:20:11uh string completed. So you can see that
3:20:14from where you are getting this one
3:20:17receipt chunk means that means you are
3:20:19writing. Now if you notice one thing
3:20:22when you have created the readable we
3:20:24have this one in lower case but this
3:20:26transform stream is going to do what is
3:20:28actually transforming this stream and
3:20:30then it actually passing this one to a
3:20:32writable stream and then it's going to
3:20:34simply saying that okay now I've
3:20:36received it for for example here we are
3:20:38simply logging right but in actual
3:20:39project maybe you're writing this one to
3:20:41a file system or maybe you're sending
3:20:43this data to some place we are storing
3:20:45the data to our cloud whatever it is but
3:20:47you can see that this is actually
3:20:48received the data Right. So chunk we are
3:20:51getting capital and who is doing this
3:20:53capital? This uppercase transform this
3:20:55stream and then we simply telling that
3:20:57now this call back is telling okay
3:20:59writeable stream task is done. You go
3:21:01next. Now it will check here we don't
3:21:03have any other stream. So now stream
3:21:05will be completed. So this is how you
3:21:07can make use of this stream. So couple
3:21:10of key points you have to understand
3:21:11that stream work with chunks. Streams
3:21:13work with chunks. Readable stream what
3:21:16it's going to do? It's going to produce
3:21:17the data. Writable stream is going to
3:21:19consume the data and it's going to do
3:21:21something. And transform stream is
3:21:22actually very important. Transform
3:21:24actually doing something. It's actually
3:21:26modifying the data in the middle. See,
3:21:28it's actually converting this one to
3:21:29uppercase before it will pass to the
3:21:31right angle and pipeline is going to
3:21:33combine all your stream together. Okay.
3:21:36One thing you don't have to use stream
3:21:38everywhere. This is also another
3:21:39important concept and this is also a bad
3:21:41practice if you're using streams
3:21:42everywhere. So, so it's like oh I know
3:21:45stream and I have to show off my skill
3:21:46and then I'm using. Don't do like this.
3:21:48If your data is very large then only you
3:21:50have to use streams. Okay. So with this
3:21:53now our core module is completed. So I
3:21:57think we have almost covered most of the
3:21:58things and some of the things are very
3:22:00important. I think in other videos you
3:22:01will not find in this much details. So
3:22:04with this now let's move on to the next
3:22:06section. All right. So till this part
3:22:08what we have completed. So first section
3:22:10is completed right. So you have learned
3:22:12that what actually NodeJS is setup
3:22:15installation and all the code modules
3:22:17and the concepts and I think this is
3:22:19more than enough. See whatever concept
3:22:20that I mentioned uh that are a little
3:22:23more advanced. So for that one I will be
3:22:25creating a part three. Now you might be
3:22:27thinking that okay I already have a part
3:22:28three that I have uploaded last year but
3:22:30this is just to mention that part three
3:22:32is completely different because in that
3:22:34part three we have discussed uh
3:22:35different tech like uh I think if I'm
3:22:38able to recolct I've discussed with uh
3:22:40something like burn hono and then I've
3:22:42covered NJS but this part three will be
3:22:45completely different all right so here
3:22:46we are only going to cover NodeJS
3:22:48advanced concept why part three because
3:22:50in the part two we are going to have
3:22:52NodeJS microservices okay if you're
3:22:54following this channel you already know
3:22:55what I'm talking about so I think
3:22:57whatever we have discussed in the
3:22:58previous section that is more than
3:23:00enough okay but now the real uh concepts
3:23:02that we will start learning so first of
3:23:05all what we are going to learn so first
3:23:06we'll start with learning node HTTP
3:23:09module because this is where it will
3:23:11become more and more practical okay and
3:23:13from this particular section whatever
3:23:15things I'm going to repeat whatever
3:23:17things you are going to learn you have
3:23:19to do this one practically properly and
3:23:21you also have to learn that how you're
3:23:22going to apply all those concepts in a
3:23:24project where you're going to actually
3:23:26build production level API applications.
3:23:28Okay, so first we are going to target
3:23:30node HTTP module. This is what we are
3:23:32going to do after [snorts] this. Okay,
3:23:35extremely important. Okay, I'm going to
3:23:36repeat once again. Please note it down.
3:23:39There will be one section where I'm
3:23:41going to add a postgress full course.
3:23:42Now this particular part that we will
3:23:46have before starting our actual NodeJS
3:23:48project, this video is already uploaded
3:23:50on YouTube. Okay, but why I'm adding?
3:23:52because if I'm not wrong, I think most
3:23:54of the people haven't watched because
3:23:56that video didn't get that much
3:23:57response. Now why I'm telling this is
3:23:59absolutely mandatory. Uh this particular
3:24:02section, the reason is very simple
3:24:04because in this particular section, I
3:24:06think this will be around 4 hours. Each
3:24:08and every topic I discussed that if
3:24:10you're a beginner, this will be
3:24:12absolutely perfect video for posgress to
3:24:14start. So I'll highly recommend like
3:24:16100% recommend to complete this
3:24:18particular section before you will jump
3:24:20to next part. Okay. So I just wanted to
3:24:23repeat once again once we'll complete
3:24:25this node HTTP module we are going to
3:24:28have have one complete dedicated
3:24:29postgress section. Now if you recolct
3:24:32right if you watch my previous NodeJS
3:24:33part one video there also I have kept
3:24:35one section for MongoDB because that
3:24:37project uh or that video was completely
3:24:39dedicated to MongoDB because this one we
3:24:42are going to cover posgress and also in
3:24:44NodeJS microservices also we are going
3:24:45to have Postgress. Highly highly
3:24:47recommended do not skip this particular
3:24:49section. Okay. If you skip it's fine if
3:24:51you already know but but if you don't
3:24:53know like postgrad basic concept then
3:24:55you have to watch this. So this will be
3:24:57prerequisite. This particular section is
3:24:59prerequisite for the next section.
3:25:01[snorts] Once we cover this right we are
3:25:03going to have our actual practical
3:25:05project. Now you can me see that I
3:25:06clearly mentioned this will be all in
3:25:08one covers everything. So what I mean by
3:25:10this? So let's discuss or else let's not
3:25:12directly jump to the uh practical part
3:25:14because you need to know right that what
3:25:16are the things you have to learn. So
3:25:18what I mean by this allin-one. So in
3:25:20this particular project you are going to
3:25:22understand how we are going to use
3:25:24posgress with docker. Okay. So I'm going
3:25:26to give you some see we are not going to
3:25:28have too many things around docker. If
3:25:30you're thinking okay I don't know
3:25:31docker. So we are going to have one
3:25:32single docker compost. If you want you
3:25:35can also skip docker but I will highly
3:25:37suggest to use it because it is very
3:25:39very helpful and it is also production
3:25:42oriented right. So you'll understand
3:25:44that how we can create posgress pool or
3:25:46posgress connection. how you are going
3:25:48to implement a proper folder structure
3:25:50when you're going to implement any
3:25:52production level NodeJS application.
3:25:54Third, how you can implement CRUD. CRUD
3:25:56means create uh read, update and delete
3:26:00which is the pillar of each and every
3:26:02project. Whatever project you are going
3:26:03to build, whatever complexity of that
3:26:05project is at the end everything will be
3:26:08CRUD. So CRUD we are going to cover. We
3:26:10are going to cover authentication JWT
3:26:12authentication. We are not using any
3:26:13third party packages. Okay. Then we are
3:26:16also going to have file upload. So this
3:26:18project is going to cover everything.
3:26:19Now you might be thinking okay the same
3:26:22thing we have covered in the part one of
3:26:24the NodeJS also that I uploaded two
3:26:26years back actually yes because see when
3:26:29I'm uploading a new video the only
3:26:31difference is that this is on posgress
3:26:33that one on MongoDB and to be honest I
3:26:36will be very honest right now in this
3:26:39particular uh time right learning
3:26:41posgress will give you too much age
3:26:43because most of the products and level
3:26:44application will see that they're not
3:26:46using MongoDB. So I just wanted to
3:26:47mention so if you're thinking that okay
3:26:49what is the new thing in this particular
3:26:51video or on this particular project to
3:26:53be honest that is not much at the end we
3:26:55are going to cover all the backend
3:26:56responsibilities only but how you can
3:26:58create a proper folder structure the
3:27:00coding standard working with posgress
3:27:02all these things we are going to
3:27:03understand after this we are going to
3:27:06have one complete dedicated section on
3:27:08radius this also another video that I
3:27:10have uploaded same video I already
3:27:12mentioned that that will be prerequisite
3:27:14for node this video again I didn't get
3:27:16proper response I'm going to add this
3:27:17section. If you want to understand how
3:27:20to work with background jobs bmpq then
3:27:22this is also prerequisite section. So
3:27:25why I'm mentioning all of this so that
3:27:27you will be in track. So first we'll
3:27:28start with node http then complete your
3:27:31posgress section. Once complete please
3:27:34do not jump directly from here to here.
3:27:36Please do not do this. Okay. I highly
3:27:38recommend if you're serious do this.
3:27:40First learn posgress then jump to this
3:27:43one. Once you'll do that learn radish
3:27:46have some patience and then go to the
3:27:48practical section. So this will be
3:27:49proper sequence. Okay. So with this now
3:27:52let's get started. The first thing what
3:27:53I have done I created a single folder.
3:27:56You can see that we don't have anything
3:27:57else here. I think we have already
3:27:59covered all these things right. How you
3:28:00can create package.js and tsconfig in
3:28:03the previous section. So that is the
3:28:04reason I haven't uh I'm not showing you
3:28:06all of this. So what we are going to do
3:28:08in this one we are going to understand
3:28:09couple of things. So first we have to
3:28:11understand the basic HTTP server and the
3:28:13concept how you can implement routing uh
3:28:17body reading body and also JSON
3:28:19response. These four will be main
3:28:21pillar. Why we are covering all of this?
3:28:23Because once you start XL before that
3:28:26you need to know the core HTTP module or
3:28:28else there is no point and also we are
3:28:30going to call one very important section
3:28:31where we are going to call one external
3:28:33API because there is a possibility that
3:28:36some section will be uh that not some
3:28:38section in some projects let's say
3:28:40you're working in a company there is a
3:28:42possibility that you will have some
3:28:43third party API that you need to call so
3:28:46you also need to understand some of the
3:28:47concepts there also so with this now
3:28:49let's get started so first we'll start
3:28:51with understanding the basic HTTP be
3:28:53server concept from the next part. Okay.
3:28:55So let's start creating the first file.
3:28:57Okay. So for this one what we are going
3:28:59to do right let's see we don't have to
3:29:00create any proper folder structure or
3:29:02anything for now because we need to
3:29:04understand the concept right. So as
3:29:06usual we will create single file like
3:29:07this. So I'm just going to give this one
3:29:09as basic http server.ts.
3:29:13So first what are the things that we
3:29:16need to understand. First we need to
3:29:17understand that from which package we
3:29:19are going to import http right. So first
3:29:21let's do this and we I think you know
3:29:23very well right. So I'm going to keep
3:29:25complete section practical only. There
3:29:28is no point of explaining only concept
3:29:30then do practical but we are going to do
3:29:32vice versa. First we're going to write
3:29:33the practical and then write the concept
3:29:34in this file only just like we have done
3:29:36in the previous section. So input http
3:29:39from this module. So from which module I
3:29:41need to do. So I'm going to do node and
3:29:43then you're going to give colon and this
3:29:45will be your http right? You can also do
3:29:47something like this. So do http. Okay,
3:29:50but I'll do like this. So we are getting
3:29:52from node HTTP module. So this will be
3:29:55my module. First what I'm going to do
3:29:57right, I'm going to take one port that I
3:29:59wanted to run this on 30,000 port. So
3:30:02first we need to understand that how you
3:30:04can create a HTTP server. So to create a
3:30:06HTTP server, you need to use something
3:30:08called HTTP.create server. So this
3:30:10create server is a method that is going
3:30:12to do what? It's going to create a
3:30:14low-level HTTP server. Okay. So first
3:30:17let's create the server. Then we'll
3:30:18understand each and everything. So let's
3:30:20start with server. So I'm going to take
3:30:22HTTP and this is going to give me this
3:30:25create server. Okay. Now this create
3:30:27server is going to have something. Okay.
3:30:29So this is going to have something
3:30:30called request and this is going to have
3:30:33response. So what this is all about very
3:30:35important concept like these are like
3:30:37core concept. Okay. You can't skip any
3:30:40of these. Request is your request
3:30:41object. Response is your response
3:30:43object. So what actually this request
3:30:46object contains right? So first you are
3:30:48going to have something called as
3:30:49request and then you're going to have
3:30:51something called as response. Now you're
3:30:53going to get some error because this is
3:30:55going to not able to understand that
3:30:56what actually this is. So in this case
3:30:58we need to import something from this
3:31:00particular model. So I'm going to import
3:31:02a type and I'm going to tell that okay
3:31:04this is my incoming message that the
3:31:07request I'm going to receive and this is
3:31:09my outgoing or this is my server
3:31:11response not outgoing but this is my
3:31:13server response. So I'm going to import
3:31:14type and here we're going to have
3:31:16something called a server response. So
3:31:18first I'm going to tell that okay this
3:31:20is my incoming request
3:31:24and this is my server response.
3:31:28Okay. So now after this what we going to
3:31:30do right also we have to take this one
3:31:33as a call back and here now we are going
3:31:37to do something. So first we need to
3:31:39understand here that what is happening.
3:31:40So first we understand that so let's
3:31:43write it like this. I'll do http dot
3:31:45create server. This is going to create
3:31:48low-level
3:31:50http server. And second we have a call
3:31:55back right. So this is our call back.
3:31:58Now this call back is going to run for
3:32:00every incoming HTTP request. So we have
3:32:03a call back. So call
3:32:05is going to run for every incoming
3:32:09request that you're going to get
3:32:13incoming HTTP request. What this request
3:32:16means? So this request is nothing but
3:32:19this is our request
3:32:22object.
3:32:24What this request object contains. Now
3:32:26this is going to contain couple of
3:32:28things, right? So first if I just do
3:32:29here something like this. So I'll do
3:32:31request dot and you can see that you're
3:32:33going to have lot of things here. So
3:32:34many things are happening. So some of
3:32:36the very important point you have to
3:32:37understand. First there will be a
3:32:39request method. Okay. Now this request
3:32:41method is going to tell the type of
3:32:43method that or type of request that we
3:32:45are doing. So for example this method
3:32:48can be your get this can be your post.
3:32:50This can be your put this can be your
3:32:52options. This can be your delete
3:32:55something like this. Okay. So this is
3:32:57your request dot method. Then you're
3:32:59going to have something called request
3:33:00URL. What this is going to tell this is
3:33:02act this is actually your requested
3:33:04path. Okay, for example, we are calling
3:33:07to this path slash or we are calling to
3:33:09this / user. So this is your path or so
3:33:12in this case this will be your request
3:33:14dot URL. Okay, then we have something
3:33:16called very important we have request
3:33:18headers. So this is actually these
3:33:21headers are nothing but so these headers
3:33:24will be the actual metadata.
3:33:27actual metadata
3:33:30sent by the client. So what I mean by
3:33:33client client is so in this case your
3:33:35client can be let's say you have a
3:33:36reactjs application so you're sending
3:33:37the headers okay and next you have
3:33:40something called request body right the
3:33:42request body is nothing but so this will
3:33:44be your data that will be sent by the
3:33:46client right whenever we are going to do
3:33:48let's say post or put type of request so
3:33:51this will be your request object then
3:33:53we're going to have our response so
3:33:55which is our response
3:33:57object right so this is nothing but so
3:34:00this particular object will be used by
3:34:02our server to send something back to the
3:34:06client. Okay. So let's say you're doing
3:34:08some API call and once you do the API
3:34:11call or whatever DB operations you are
3:34:13doing you are doing so you're going to
3:34:15get some response back and that response
3:34:18you need to render in your UI so that
3:34:20your user can see okay so in that case
3:34:23that particular response you have to
3:34:24send back okay so because you are going
3:34:27to have your back end and front end
3:34:28right so until unless you're going to
3:34:29send the data back from your back end to
3:34:32front end there is no way you can render
3:34:34the data correct so this response is
3:34:37going to help you in that particular
3:34:38case. So it's going to send something
3:34:40back to your client. So what are the
3:34:42things going to send? So you're going to
3:34:43have something called status code. So
3:34:45this status code is going to tell that
3:34:47okay if the response or if the operation
3:34:50that we are doing if that is successful
3:34:52or not then you're going to also pass
3:34:53the response headers and then you're
3:34:56going to have your response body.
3:34:59Okay. So this is all about the main
3:35:02concept. Okay. So first you're going to
3:35:04have what? So HTTP create server is
3:35:06going to create your actual HTTP server.
3:35:09There will be a call back which is going
3:35:10to run every time there will be HTTP
3:35:12request. This is your request object and
3:35:14this is your response object. Okay. So
3:35:16now first of all what we are going to do
3:35:18right. So in this
3:35:21so let's remove this. So first I'm just
3:35:23going to do con
3:35:26method. So this will be my request do
3:35:28method. So this will be the first thing.
3:35:32Again I think here we have let's write
3:35:34it only once so that you remember. So
3:35:36here we are going to have request dot
3:35:37method can be get. Okay. So in this case
3:35:40get means you are reading data.
3:35:43Then you're going to have post. So post
3:35:45means you're going to creating some new
3:35:47data. So you're going to create data or
3:35:50creating or let's do create data. Then
3:35:53you're going to have put. So put will be
3:35:56you are actually replacing the data.
3:35:58Replace data. Then you're going to have
3:36:01something called patch. So patch is you
3:36:03are updating but you're updating partial
3:36:06data or let's update partial data and
3:36:11then you're going to have delete. So
3:36:13delete is nothing but I think this is
3:36:14very easy to understand that delete is
3:36:16nothing but you are deleting the data.
3:36:18So delete data. So normally these are
3:36:21very very important. This is what you're
3:36:23going to use most of the times there are
3:36:24lot so many but if you're learning
3:36:27NodeJS in depth okay in-depth see again
3:36:30in depth in the sense I'm not talking
3:36:31about you have to be like a node master
3:36:34okay but if you're working in a company
3:36:36right let's say you're targeting for job
3:36:39this is more than enough why I'm telling
3:36:41because this is when you're going to
3:36:43implement some actual products and level
3:36:46application even in your company right
3:36:47you'll see that most of the times you
3:36:49are going to use all of these so this
3:36:52This is about your request dot method.
3:36:55So then we're going to have our URL. So
3:36:56this will be my request dot URL.
3:37:01Okay. So I already mentioned this one.
3:37:03So this will be request URL is uh
3:37:05nothing but that in which path the
3:37:08client is actually requesting. So this
3:37:10will be in which path the client
3:37:15is actually requesting.
3:37:20Okay. So this will be your request dot
3:37:21URL and then you're going to have what
3:37:24we are going to have something called
3:37:25headers. So for example here let's do
3:37:29one thing. So I'm just going to do one
3:37:30user agent header. So how you can do
3:37:32this? You're going to do request and
3:37:34you're going to pass a header and then
3:37:36here you can pass something called user
3:37:38agent. Okay what actually headers are
3:37:40see headers are nothing but your
3:37:43metadata. Now what how I will explain?
3:37:45So headers are nothing but extra
3:37:47information that we send along with our
3:37:50request. Okay. So this will be our extra
3:37:52information. For example, let's say what
3:37:53is our browser type. What is our token
3:37:56authorization token? What is our content
3:37:58type? Whether we are sending JSON
3:38:00content or we are sending text normal
3:38:03text. All these things you're going to
3:38:04send in your uh request headers. Okay.
3:38:07And now once this is done then we have
3:38:10something called our response. So let's
3:38:11say I'm just going to do response. And
3:38:13you can see that we're going to have
3:38:14response dot status code. If you do
3:38:16response dot right, you're going to get
3:38:18lot of options here, right? You can see
3:38:20that. So do something like request dot
3:38:23send date, set header, all of these. So
3:38:25for now, let's do request, sorry,
3:38:27response status code. And I'm just going
3:38:29to do this one as 200. What this is
3:38:32going to do? This is going to set your
3:38:34HTTP status code. Okay, here 200 means
3:38:39status sorry uh request is successful or
3:38:42status is successful. Now here you can
3:38:45have so many for example 201 when you're
3:38:47going to create something you're going
3:38:49to have 400 you'll have 500 you have 429
3:38:52like there are so many okay you're going
3:38:54to have 401 so all these now each and
3:38:57every status code we use in a certain
3:39:00position or certain situation to
3:39:02represent something so then you are
3:39:05going to have one more important which
3:39:06is nothing but header so let's say I'm
3:39:09adding some header here so in this case
3:39:11I'm going to add a content type so what
3:39:14actually the content that I'm sending.
3:39:16So in this case I have to mention that
3:39:18okay whether I'm sending a JSON format
3:39:21we are sending in a text format all
3:39:23these. So for example let's say I wanted
3:39:24to send only text. So here this set
3:39:28header what this is going to tell this
3:39:29is going to tell your client that what
3:39:31kind of response we are sending here it
3:39:34is normal text. Now one thing you have
3:39:36to understand okay that if you don't add
3:39:38this particular header the browser okay
3:39:42still it can show the response but here
3:39:45setting it always help because for
3:39:46example let's say we are sending a JSON
3:39:48so I have to mention that content type
3:39:49will be application/json
3:39:51something like this now what I need to
3:39:53do right I have to whatever this server
3:39:55that I created I have to end this
3:39:58particular request so how I'm going to
3:40:00do that or not request I'm going to tell
3:40:03we have to finish this particular
3:40:05response response and to finish this
3:40:06what we have to do right we have
3:40:07something called response dot end what
3:40:10this response do end is going to do this
3:40:12is going to finish this particular
3:40:14response now this is actually very very
3:40:16important because why because every uh
3:40:18request we are going to have at the end
3:40:20you are going to have some kind of
3:40:21response correct that is the reason
3:40:23you're creating the request what will
3:40:25happen if you don't add this on this
3:40:26particular thing if you don't add right
3:40:28the browser or the client it's going to
3:40:30wait because you it will think that okay
3:40:32you are sending something but if you're
3:40:34not sending it's going to do it. So now
3:40:36for example, let's say maybe let's let's
3:40:38do like this. I'm just going to do basic
3:40:41HTTP node server.
3:40:44Okay. And maybe let's render the method.
3:40:47So I'm just going to render the method
3:40:49here. Let's render the URL also. Let's
3:40:52render the maybe user agent.
3:40:57I think these three is fine. Okay. So
3:40:58save this. So now is this completed? No.
3:41:02Why? Because when we will start a
3:41:06particular request or we are going to
3:41:08get any response back. So in that case
3:41:11uh what we have to do we have to listen
3:41:13that server should listen to a certain
3:41:15port. Okay. So server.list we have a
3:41:18method that is going to do it's going to
3:41:20start the actual server. Okay. So first
3:41:23what we have to do right? So we have to
3:41:25do server and this is going to give you
3:41:27this listen. We are going to pass the
3:41:28port. Okay. You listen to this 30,000
3:41:30port. Now what will happen right? before
3:41:33listen this server exist but this server
3:41:36exist in your memory okay but it's not
3:41:38going to accept any request why because
3:41:40this is not running once you add this
3:41:43listen right what is going to do right
3:41:45so node is going to process this and
3:41:47it's going to wait for that HTTP request
3:41:49so whenever you are going to do this
3:41:51request it's going to run this
3:41:52particular method and it's going to do
3:41:54its job whatever it's going to do so now
3:41:56in this case this is going to get a call
3:41:59back and here what you can do right uh
3:42:02So I'm just going to do here log and
3:42:04maybe let's do server
3:42:07is now running on port and let's give
3:42:12this one port here right so I'm just
3:42:13going to pass a port
3:42:18let's say maybe let's change this one
3:42:20for because I already have so many
3:42:22projects that I have created right maybe
3:42:23something some other things are running
3:42:25so let's keep 5,000 only for now so
3:42:27let's save this so now what we going to
3:42:30do right we will just add one script in
3:42:33our package dojson and let's go here.
3:42:36Let's remove this.
3:42:39So I'm just going to do 01.
3:42:43So this will be tsx. So you go to
3:42:45source/
3:42:47and you have this, right? So I'm just
3:42:48going to rename copy this and then you
3:42:52run it. Paste it here. That's it. So
3:42:54save this. So now what you can do? So
3:42:56just to check this one. So I'm just
3:42:57going to do npm run and then you can do
3:43:0001 because why? Because we've given this
3:43:02one as 01 right single script this one.
3:43:05So now let's run this. You can see that
3:43:08server is now running on port 5,000. So
3:43:11that means this is actually working
3:43:13fine. So now what we can do right so
3:43:15let's go here and maybe let's do local
3:43:18host and I'm just going to do 5,000
3:43:20because we're running on 5,000. What
3:43:22you're getting? We're getting basic HTTP
3:43:23node server. This is get request right?
3:43:26you're getting your user agent right and
3:43:28all the details that whatever you have
3:43:29added here. Okay. So now I think this is
3:43:32completed. So first of all you
3:43:34understand some of the things right that
3:43:36what actually create server method is
3:43:38what is request object response object.
3:43:41Okay. And then how you are going to set
3:43:43headers and all the things. Now remember
3:43:45this status code and everything when
3:43:47we'll start our actual project
3:43:48implementation this will be easier
3:43:50because whatever you're seeing all these
3:43:51status code we are going to anyways use
3:43:53in our NodeJS project.
3:43:55So with this now let's move on to the
3:43:57next concept. Okay. So now let's move on
3:43:59to the next one. So next one let's
3:44:01understand some of the routing concepts.
3:44:03Okay. So I'll do routing. DS. So first
3:44:06of all let's do one thing. Okay. Let's
3:44:08close this one. Okay. Clear this.
3:44:13So first uh let's do one thing. Let's
3:44:15import this because we need this. We
3:44:18have already discussed this one. We
3:44:19don't have to again uh discuss. So let's
3:44:21take the port as 5,01. this time and now
3:44:26what we will do right so let's create
3:44:27the server first now if you see that how
3:44:30I've actually created see remember
3:44:32whatever video that you are seeing right
3:44:33this particular course
3:44:36you don't have any idea how much time I
3:44:38actually spent while creating this video
3:44:40the point is not about the video
3:44:42recording or the editing the point is
3:44:44how I'm going to structure uh this
3:44:46particular curriculum that is the most
3:44:48important part structuring is very very
3:44:50important means this particular concept
3:44:52should come after that concept And that
3:44:54is where the main teaching will come.
3:44:56You understand what I'm talking about?
3:44:58For example, let's say in the previous
3:44:59section we have already discussed that
3:45:01how you can create uh server using HTTP
3:45:04create server. Now when in the next part
3:45:06I'm going to use the same concept. I
3:45:08don't have to explain because from the
3:45:10previous section you will be able to
3:45:12apply that particular concept in this
3:45:14one. Okay. And you'll notice this
3:45:16particular pattern throughout this uh
3:45:18video. Okay. Till the end. So let's do
3:45:20one. So we'll do http.create server. So
3:45:24this is going to give us a call back. So
3:45:25I'm just going to do request which will
3:45:27be my incoming message. Then I'm going
3:45:29to have the response which will be my
3:45:30server response. Okay. And [snorts] here
3:45:32first of all what we are going to do
3:45:34right. So let's take our method. So I'm
3:45:36just going to take the method and this
3:45:38method will be so I'm going to take
3:45:39either it will be the request method or
3:45:42by default I'm going to take this one as
3:45:43get. So this will be by default it will
3:45:46be get method. Okay. So now what we are
3:45:50going to do right? So first you have to
3:45:52remember one thing that what this uh
3:45:54okay let's first do one thing that I'll
3:45:57do request URL and we already discussed
3:46:00that we have something called request
3:46:01URL right but what this request do URL
3:46:04actually contains now this contains the
3:46:06path that requested by the client okay
3:46:10so let's say if I'm doing like this so I
3:46:13have http and then I will do local host
3:46:16and then I'll do 3,00 okay/ users
3:46:20something like this. So I'm taking 3,000
3:46:22only. That's fine. But let's take 5,0001
3:46:24because we're going to run this. In this
3:46:26case, what will be your request URL?
3:46:29Your request URL will be / users. Okay,
3:46:33only this part. Similarly, let's say if
3:46:35I just do here / user and then here I'm
3:46:38just going to take only for the user ID
3:46:40one. So in that case, this will be only
3:46:43of this user ID equal to one. Okay. So
3:46:46request URL only this part. Okay. So now
3:46:49when we are going to implement routing
3:46:51or we understand routing we usually want
3:46:54only the path part right only the path
3:46:57this part okay so now how we are going
3:46:59to get this so in that case what we have
3:47:01to do right we are going to convert this
3:47:03request dot URL into a URL object and
3:47:06then we are going to read the path name
3:47:08so first we have to convert so how we
3:47:10are going to convert so what we have to
3:47:13do right let's cut it so we have
3:47:14something called new URL okay and this
3:47:17is is going to give So you can pass this
3:47:19ukulele or this will be
3:47:23by default it will be like this and then
3:47:26what we going to pass uh pass right. So
3:47:28let's take this one as http and here I'm
3:47:31simply going to do uh request dot header
3:47:34and then I'm going to get something
3:47:36called host. Okay and now what we can do
3:47:39right we can simply read the path name.
3:47:41So I'm just going to do path name and
3:47:43this will be a request url dot you have
3:47:45something called path name. So this is
3:47:47going to give you the actual path name.
3:47:49Okay. So now first of all let's do one
3:47:51thing. Let's take rest and then I'm just
3:47:54going to do a set header. And for now
3:47:55I'm just going to pass the content type
3:47:57as text only. So the content type will
3:48:00be text/plain.
3:48:04And then what we have to do right so now
3:48:07what I can do right we can simply check
3:48:09that if the current method is get. So
3:48:12I'm simply going to check if the method
3:48:14method is equal to equal to get and if
3:48:17the path name if this path name is equal
3:48:20to let's say I'm sending request from
3:48:22this path from the health route. So this
3:48:24is our route. Okay. So you'll understand
3:48:26what I'm talking about. So in that case
3:48:28what I'm going to do right I'm just
3:48:29going to do raise dot status code will
3:48:31become 200. I'm just going to do race
3:48:34end. So I have to end it right. We have
3:48:36already discussed. So I'm just going to
3:48:37do server is now or server is healthy.
3:48:41And then I'm simply going to do return.
3:48:44Okay. So if the path name is health,
3:48:46you're going to return this. Now you'll
3:48:47understand one thing that even though if
3:48:49you don't have any third party packages,
3:48:51sorry not packages, framework like X or
3:48:53let's say you're using something else
3:48:55still using only node HTTP you will be
3:48:57able to implement all of these okay
3:49:00without using any framework also. So
3:49:01that is the reason you have to
3:49:02understand the basic concept. Similar
3:49:04way what I can do right copy this and
3:49:06then I can paste it here. Okay. the
3:49:08method is get and now if the route is
3:49:10instead of health if this is users so
3:49:12I'm just simply going to pass here list
3:49:14of users so I'm just going to do list of
3:49:17users and then we are going to return
3:49:19similarly you can do for other also for
3:49:21example let's say if I copy this and now
3:49:23I'm simply going to change this one to
3:49:25if this is post not get request okay and
3:49:28the path name is users so I'm just going
3:49:30to change this one to 201
3:49:33we usually we already expl sorry we
3:49:35already explained this one right if you
3:49:37recollect 20 is 201 is when we are going
3:49:41to create something. So that is the
3:49:43reason I'm taking this one as method is
3:49:45post and in that case I'm simply going
3:49:47to do user created successfully
3:49:51something like this. Now here um you can
3:49:53also take one for delete also. Okay. And
3:49:56then what I have to do right now see
3:49:58there is a possible that when user is
3:50:00going to send one particular request
3:50:03let's say user can send any random
3:50:06request also to any path for example
3:50:08some blah blah. Now this path is not
3:50:11present. There is a possibility right
3:50:12that this route is not present in your
3:50:14back end. So in that case you have to
3:50:15inform the user okay this route is not
3:50:17found. So to do this what you have to do
3:50:19is we're going to pass status code will
3:50:21be 404. So 404 means this route is not
3:50:24present. 404 means not found. So
3:50:27something is not found not found here.
3:50:31Right? And then in that case you're
3:50:32simply going to do race.
3:50:35And I'm simply going to do route not
3:50:38found. Okay that's it. So now what we
3:50:41going to do? Let's go here and then
3:50:43we're going to copy this and I'm simply
3:50:45going to paste it here. save this. So
3:50:48let's go to package dojson, copy,
3:50:52paste and then we are going to simply
3:50:56copy this
3:50:59paste here and change this one to two.
3:51:02So save this and now what we going to do
3:51:04right? So let's run it. So npm run 02.
3:51:07Now you'll see that this is now running
3:51:09on 5001. So now what I can do right
3:51:11let's go here and then I'm going to
3:51:13create new request and then here I'm
3:51:16simply going to do what right so let's
3:51:18copy this from here
3:51:21and then I'm simply going to do 501 and
3:51:23then I'm going to pass this one as
3:51:25health okay see what will happen so you
3:51:26can see that you are getting server is
3:51:28now healthy now the reason you are
3:51:30getting because it's now matching here
3:51:32why because what we have done right this
3:51:34request URL is now going to give you /
3:51:36health because this is the path name
3:51:39right this is is the path name that
3:51:40you're going to get and if the path name
3:51:42is matching so in that case you're going
3:51:43to get server is healthy if you're
3:51:45passing this one as users so you're
3:51:48going to get that okay list of users
3:51:50okay if you're passing what what else so
3:51:52if I change this one to post and then if
3:51:54I send this one user created
3:51:56successfully but in case if I just
3:51:58change this one to get and if I give a
3:52:00random route which is not present so
3:52:02I'll do random route not present
3:52:07present
3:52:09here and then if you send this right
3:52:11you're going to get route not found and
3:52:12you're going to get a 404 you're getting
3:52:15all of this. So this is where it is very
3:52:17important you have to understand couple
3:52:18of things here first of all what
3:52:19actually method is what is path name
3:52:22right how you're going to get the path
3:52:24name what is status code what actually
3:52:27response you are sending and also that
3:52:29you also understand one very important
3:52:31point and that is if we don't have any
3:52:33route that is not present so in that
3:52:34case we pass this one as 404 okay why
3:52:37this status code are extremely important
3:52:39because when you're going to implement
3:52:40actual code right let's a production
3:52:42level application you're going to build
3:52:44you need to know which status code you
3:52:46need to use in which situation and that
3:52:49is very important. Okay. So I think with
3:52:51this this is now completed uh routing
3:52:53section or concept. Now let's move on to
3:52:55the next one. Okay. So moving to the
3:52:56next one. So let's understand that how
3:52:59we can read our request body in plain
3:53:01NodeJS because anyways in the next
3:53:03section we are going to introduce
3:53:05express. So you're going to understand
3:53:06all these concept in better way but
3:53:08still you have to understand that how
3:53:09you can uh do the same thing or do the
3:53:13same implementation without using any
3:53:16third party like uh frameworks. Okay. So
3:53:18first I'm just going to give 03. Let's
3:53:20give this one as maybe reading uh body
3:53:24ts. So first let's close these two.
3:53:28And here also let's do one thing. Let's
3:53:31rename this. Copy this. And then let's
3:53:34add one more here. Okay. So I'll do 03
3:53:39and this will be tsx
3:53:42source/ this. Save this. Okay. So first
3:53:46of all we need to copy this tool
3:53:49from here. I'll copy this.
3:53:52Let's keep this on 5002 so that you'll
3:53:55understand what is happening also. Let's
3:53:56close this. And here first we are going
3:53:59to do so we'll create our server.
3:54:03So this will be http do.create server
3:54:07and here we're going to have the call
3:54:08back. So request will be your incoming
3:54:10message. Response will be your server
3:54:13response.
3:54:15And here first of all we going to get
3:54:16couple of things. So first what we need
3:54:18to get right. So we going to get our
3:54:20method. So let's go here. So we'll get
3:54:23our method which will be request dot
3:54:25method. or else let's keep this one as
3:54:27get. Next we are going to get our path
3:54:30name. I think this part we've already
3:54:32discussed. So let's copy this from here
3:54:34and then we'll paste it. So now also
3:54:37let's set the uh header as pl uh text
3:54:41only. Save this. So now what I going to
3:54:43do right? So first of all I'm simply
3:54:45going to do if method is equal to get
3:54:50and then what you're going to do what
3:54:52else? Maybe let's do one thing for get I
3:54:54think we've already discussed. So let's
3:54:56do this one as post only. This is where
3:54:58we are going to do something. So here
3:54:59what I'll do I'm simply going to check
3:55:01if the path name is equal to equal to
3:55:04users then we are going to do something.
3:55:06Okay. So now this particular post is now
3:55:10a post request. Okay. This particular
3:55:12path not post this particular path is
3:55:14now a post request. Post means this is
3:55:17going to expect some kind of JSON
3:55:18request body. Okay. So for example let's
3:55:21say when you are sending something from
3:55:23your UI you are going to send your name
3:55:25and email something like that. So in
3:55:27that case what I'll do right is I'm
3:55:28going to create a type and this give
3:55:31this one as maybe let's say create user
3:55:33body that I'm actually creating some uh
3:55:36user. So where I'm going to keep the
3:55:38name as string and also I'm going to
3:55:40pass email which will be string these
3:55:42two things. So now what I'm going to do
3:55:45right so first of all this particular
3:55:47data that I'm going to send from my UI
3:55:49side I need to read it in my back end.
3:55:51Okay. So for now what I can do right so
3:55:53here we can make use of chunks. So here
3:55:56first of all I'm going to take chunks
3:55:58and these will be buffer and here what
3:56:00I'm going to do let's take this one as
3:56:02empty for now. What we are simply doing
3:56:04right we're actually storing our
3:56:05incoming chunks here. Now what these
3:56:08chunks will be each and every chunk that
3:56:09we are going to store that will be part
3:56:12of your request body. Okay. Now what we
3:56:16going to do right? So first of all let's
3:56:17do one thing. Let's take a request and
3:56:19here we are going to take a on uh
3:56:21listener. Now what we going to do right
3:56:23here we have a method. Oh sorry we have
3:56:25a event called data. What this data
3:56:28event is going to do? This data event is
3:56:31going to run every time node is going to
3:56:34receive your body chunk or new body
3:56:37chunk. Let me write it or else it will
3:56:38be difficult. So this data event is
3:56:42going to run is going to run every time
3:56:47node is sorry node receives
3:56:50a new body chunk. So this event is going
3:56:54to be triggered. Okay.
3:56:57when you're going to send small JSON
3:56:59body. So maybe this will run only once.
3:57:02If you're sending larger body, this
3:57:04might run multiple times. So now what we
3:57:07are going to do right? So this is going
3:57:08to receive chunk and chunk type will be
3:57:12buffer. Okay. So now what I going to do
3:57:14right? So first I'm going to take the
3:57:16chunks that we have and then I'm going
3:57:18to post this chunk that I'm receiving
3:57:21here. So I'm just posting this one to
3:57:23this chunk array. Okay. Now what are we
3:57:26going to do? We going to take a end uh
3:57:28here. So I'm just going to do request
3:57:30dot end sorry request dot on and this
3:57:34will be my end uh event. What this end
3:57:37event is going to do. So this is going
3:57:39to run when very very important you can
3:57:41note it down. This end event is going to
3:57:44run when the full request body arrived.
3:57:47Means node already received the complete
3:57:49request body. Okay. Now what will be the
3:57:52proper way to frame this? All right
3:57:55everyone. So I just got a phone call. So
3:57:56guys so what I was talking about that
3:57:58when this particular event is going to
3:58:00run that when the node is going to
3:58:02receive the complete request body. So
3:58:04this the proper way to frame this one
3:58:06will be that combining [snorts] all the
3:58:08chunks. Okay. So what this is going to
3:58:10happen right until unless this
3:58:12particular event will run completely
3:58:15node will not have the complete request
3:58:17body you're getting. So once it will
3:58:19have the complete or full request body
3:58:22that time this is going to run this
3:58:24particular event. So here what we are
3:58:25going to do right. So let's take the
3:58:28call back. So first of all I'm going to
3:58:29get the raw body and this will be so
3:58:32first of all I'm going to take buffer
3:58:34dot contact here we're going to pass the
3:58:37chunks because are going to receive all
3:58:39the chunks because this is going to push
3:58:41all the every chunk to this array and
3:58:44then I'm simply going to do a string. So
3:58:46let's do two string and let's pass a
3:58:48UTF8.
3:58:50Okay. So now what this buffer do concat
3:58:54is going to do? This is going to combine
3:58:55all the received chunks into one buffer.
3:58:59Okay. I hope this is clear. Now first of
3:59:01all let's give a check that if this body
3:59:04is not received because there is a
3:59:05possibility that user haven't sent
3:59:07anything. So in that case what you're
3:59:09going to do? So I'm just simply going to
3:59:10do race dot status code will now become
3:59:12400 because there is a error and message
3:59:14we're going to send that okay your
3:59:16request body is required or empty and
3:59:20then we are going to just do return okay
3:59:23and now what we going to do right we're
3:59:25going to actually parse this so I'm just
3:59:27going to do body and this will be JSON
3:59:29dotparse and here we're going to pass
3:59:31your raw body and now what will be the
3:59:34type now this is very important okay so
3:59:36the type will be create user body why
3:59:39Because this is the format that you are
3:59:40actually expecting. Consider if the user
3:59:43is not sending name and email. So in
3:59:45that case let's say it's sending instead
3:59:47of name it's sending address or instead
3:59:49of email it sending age that is a
3:59:51possibility right. So we need to
3:59:52properly typed the body. So the body
3:59:56format will be this. So in that case now
3:59:58I can uh clearly check this. Okay. The
4:00:00body name is not present or if the body
4:00:04do email is also not present. So in that
4:00:06case I'm simply going to do race status
4:00:08code will be what 400 because 400 is we
4:00:11are using for our error okay not emit
4:00:14man this will be end. So in that case
4:00:16I'm simply going to do both name
4:00:19and email is required and then I'm
4:00:24simply going to do return. So now in
4:00:28this point if you notice in this
4:00:30particular point what will happen right
4:00:32everything is actually done. So we
4:00:33already check all the age cases. Okay.
4:00:36So what I mean by H cases because this
4:00:37is very important when you are working
4:00:39with Okay. One more thing I think we
4:00:42missed it. So let's quickly do this one
4:00:45after this right. Let's take a try catch
4:00:47block. So that is also good practice. So
4:00:49put all of this inside a try. Okay. So
4:00:52here what I was talking about that when
4:00:54you're actually implementing any API
4:00:56right the first thing what you have to
4:00:59consider that when you're doing the
4:01:00planning that whether you are covering
4:01:02all the age cases or not because
4:01:03covering age cases is very important
4:01:05what I'm talking about age cases for
4:01:06example this is one age case right age
4:01:09case means the error can happen so you
4:01:11are actually preventing the error
4:01:12similarly this is another age case here
4:01:15okay so now but this is the try and here
4:01:18I'm just going to take a catch now in
4:01:20the catch now This is not yet completed.
4:01:22try you need to do so in the catch I'm
4:01:24simply going to do rest status code is
4:01:26maybe 400 and let's send rest dot end
4:01:30and I'm simply going to do invalid
4:01:32JSON body something like this and now
4:01:35once here once you check all of this
4:01:37right what you can do right now
4:01:40if there is no error so in that case you
4:01:42simply do
4:01:44raise dot status code is 201 and then
4:01:46you're going to do rest dot end will be
4:01:50your user is now created now at the And
4:01:52when you're creating actual
4:01:53implementation what you're going to do
4:01:55right you are going to store all this in
4:01:57your DB but for now we'll do body name
4:02:00and your email is body email. Okay
4:02:04that's it. So this is done. So now so
4:02:07this will be your race end event. Here
4:02:10you can also take one more. So I'll do
4:02:13request do on and here I'm just going to
4:02:15pass in case if there is any error
4:02:16happen. So in that case what you're
4:02:18going to do? So we're going to pass a
4:02:20raise dot status code will be 500
4:02:23because this can be a any error right?
4:02:25So, it's sending a 500 and I'll do raise
4:02:27end and I'll simply do fail to
4:02:31create
4:02:33u uh request body or something or maybe
4:02:36let's do this fail to read request body
4:02:40read request
4:02:43body okay so I think this is done and
4:02:46then what we going to do right we are
4:02:48going to return
4:02:51that's it so this will be if the method
4:02:54is post and the path name is users. So
4:02:56in that case we're going to do all of
4:02:58this. If this is not the case in that
4:03:00case what I'll do do raise status code
4:03:02will be 404 because you are maybe
4:03:04sending to a route which doesn't exist.
4:03:07And here also I'm just going to do raise
4:03:09end will be route not found. So this is
4:03:14done and now what you're going to do
4:03:16let's copy this one from here.
4:03:20Save this and this is done. Now I hope
4:03:22that this part is clear right. So first
4:03:24what we doing we are taking a chunks
4:03:26then we are taking a event this will be
4:03:30the data event listener. So this is
4:03:31going to run every time node is going to
4:03:33receive the body chunk. We are going to
4:03:35push that chunk into our chunks in our
4:03:37end. First we are going to read the body
4:03:40raw body from. So first what this is
4:03:43going to do this is going to I already
4:03:45mentioned right what buffer uh concat is
4:03:48going to do. So buffer docon is going to
4:03:50combine all the receipt chunks into one
4:03:52buffer. Now this is very important.
4:03:54Okay. And then you're simply checking
4:03:56two edge cases. If this is not present
4:03:58that means you are not sending your
4:03:59request body then you're parsing the
4:04:01body then you're telling if the body
4:04:03don't have the name and email because
4:04:05this is the format or data format we
4:04:07need right if this is the case then also
4:04:09returning one error and then we are
4:04:11sending request dot status code 201
4:04:13means this is now successful okay there
4:04:15is no error so now what I can do right
4:04:18so let's go here clear this and I'm
4:04:21simply going to do npm run 03 this is
4:04:24now running on 5002 So let's go here.
4:04:275002
4:04:32okay/ users change this one to get
4:04:35because see if I change this one right
4:04:36now route not found because this is not
4:04:38get so this will be a post try to send
4:04:41request body is request fantastic so
4:04:43that means what happened so this
4:04:45particular part is running because
4:04:46you're not sending anything now let's go
4:04:48where you have to go to body let's go to
4:04:51raw and we have a JSON okay so in that
4:04:53case what you're going to do right so
4:04:55first I'm just going to send the name.
4:04:57So name will be sungum comma and I'm
4:05:00just going to say email and email will
4:05:03be sung at thegmail.com.
4:05:05Okay. So now if I send this user created
4:05:09with this and try to give a different
4:05:11property. So I'll do name to email one.
4:05:13And if you send this you can see that
4:05:14both name name and email is required
4:05:16because this is not the expected data
4:05:18that we need. We need name and email
4:05:21only here. So if you do John and let's
4:05:24do here John 1gmail.com send this. So
4:05:27now user is created. So that means we
4:05:30successfully actually read our request
4:05:32body without using any third party
4:05:34framework. Okay. So this is you are
4:05:36using pure node. Okay. So we are not
4:05:38using anything rather than node concept.
4:05:40This is very very important to
4:05:41understand. You see that how things are
4:05:43happening behind the scenes. Okay. So
4:05:45with this I think this part is
4:05:47completed. Now let's move on to the next
4:05:48one. Okay. So let's move to the next one
4:05:50which will be how you can work with JSON
4:05:52responses right because when you're
4:05:54creating actual project you will see
4:05:55that most of the times you're going to
4:05:56send the JSON responses okay back to
4:05:59your client. So here I'm simply going to
4:06:01do JSON and let's do response. DS. Okay.
4:06:05So first of all what I going to do right
4:06:07okay let's create the so let's copy this
4:06:10from here and let's copy this also paste
4:06:13it here and change this one to 5003 so
4:06:15that we can understand what is
4:06:16happening. We can keep the same code
4:06:18also that is also fine. So first I'll do
4:06:21http create server. So I think this part
4:06:24we have already covered multiple times.
4:06:26We have incoming request response will
4:06:27be server response and then we are going
4:06:30to have our call back. So first of all
4:06:31what we going to get? So we're going to
4:06:33get three things. We're going to get the
4:06:35method. We are going to get the request
4:06:36URL and the path name. So copy these
4:06:38three because at the end we have to
4:06:40check the path name. Right? So first of
4:06:42all what we going to do right? So here
4:06:44now we are going to create a helper.
4:06:46Okay. And this helper will be uh let's
4:06:48create this one as send JSON. Okay. Now
4:06:53first of all let's do one thing. I cop
4:06:55uh I have created some type. Okay. You
4:06:57understand what is happening here. So
4:06:59first let's go ahead and paste this. So
4:07:01first you can see that we have a user
4:07:02type, user as ID, name and email. This
4:07:06is our API response. So this is the for
4:07:07API response format that we want to send
4:07:10back to our client. So we want to return
4:07:12that if the response is or the request
4:07:15is successful. So we're going to return
4:07:17success true or false. We also want to
4:07:19return a message so that user will
4:07:22understand. Okay, for example, let's say
4:07:23from the UI side, you are submitting one
4:07:26form, right? Or let's say you're
4:07:27creating one product data or let's say
4:07:29you're creating uh maybe okay what to
4:07:32think so let's say you're creating some
4:07:34uh admin creating some user information
4:07:37okay so in that case once the that
4:07:40request is successful so that admin or
4:07:43the end user should understand whether
4:07:45that is successful or not right so in
4:07:47that case what we usually do we'll
4:07:49render some kind of message in the toast
4:07:51or let's say in a dialogue so that they
4:07:53will understand okay user is now created
4:07:55successfully why Why I'm repeating all
4:07:56of this multiple times? Because this is
4:07:58the format we are going to use in our
4:08:00next project also. And that time I'm not
4:08:01going to repeat the same thing again and
4:08:03again and success will be true or false.
4:08:05What is the data? Data is the actual
4:08:07data that I want to send to our client.
4:08:10Okay. And in case there is any error. So
4:08:12in that case I'm going to return the
4:08:14error. So that is the reason you can see
4:08:15that both are optional. So now what I'm
4:08:17going to do is I'm going to create a
4:08:19send JSON. Let's take a generic here.
4:08:21And in this one what I'm going to do? So
4:08:23first of all my response will be my
4:08:25server response. Then I'm also going to
4:08:27take a status code
4:08:30and this status code will be number
4:08:33and then I'm going to take a body
4:08:37and this will be my API response
4:08:41this one and you're going to pass this t
4:08:44here. Okay, that's it. And let's return
4:08:47here void. So first of all what we have
4:08:50to do? So first we have to set the
4:08:51status code. So first I'll do res status
4:08:54code will be the actual status code we
4:08:56are receiving here because when we going
4:08:58to call this helper the status code can
4:09:01be 200 it can be 201 it can be 400 it
4:09:04can be 401 it can be 500 also so we
4:09:06don't know what actually the status code
4:09:08is we have to set it here what this
4:09:10status code is going to tell so status
4:09:13code is going to tell the client that
4:09:14what actually happened for example 200
4:09:16means it's successful 201 means
4:09:18something we have created that is
4:09:20successful 400 Means some error happened
4:09:23and that error happened from the client
4:09:25side means client sends some invalid
4:09:26data then only 400 error we are getting.
4:09:29For example, let's say in that form we
4:09:31you uh ad sorry not admin the client
4:09:34needs to send name age and email but
4:09:37client only send name email but client
4:09:40didn't send age. So in that case we are
4:09:42going to render that okay age you also
4:09:44have to send age is a mandatory field.
4:09:46Then let's say you're getting 404. So in
4:09:48that case route not found 500 500 means
4:09:51some internal server header uh error
4:09:54happened. So all these things this rest
4:09:56do status code is going to mention and
4:09:58then what we going to do right I'm
4:09:59simply going to do r dot set header. Now
4:10:02this set header will now be content type
4:10:06extremely important concept because this
4:10:08is what we are going to use and this
4:10:10will now be not plain text this will be
4:10:13a JSON data. So in this case we are
4:10:16simply telling that okay content type is
4:10:18going to tell the client that how we are
4:10:19going to understand your request body.
4:10:21So in this case we are simply telling
4:10:22that your request body will be JSON so
4:10:25that we can parse it. So this is done
4:10:27and then what we going to do right I'm
4:10:29just going to do rest dot not same man
4:10:31rest. And I'm just going to do JSON dot
4:10:34stringify.
4:10:36This popup is extremely irritating. I
4:10:39don't like this. Okay. So this one you
4:10:41see and this will be body. Okay. So we
4:10:45want to send this uh in the stringify
4:10:48format JSON string format. So this will
4:10:51be my send JSON helper. Okay. So now
4:10:53what we can do we can use this in every
4:10:55place. How? So now let's say if we go
4:10:57here that okay now if the method is
4:10:59equal toal to get
4:11:02and the path name is equal to home home
4:11:06path. So in that case I'm simply going
4:11:08to call the send JSON and here I'm going
4:11:11to pass what response. So you to pass
4:11:13this response then you're going to pass
4:11:15what? You have to pass the status code.
4:11:18So in this case this will be 200 and
4:11:20then you also have to pass the body.
4:11:22Body will be actual data. So in that
4:11:24case let's I'm going to pass a success
4:11:26which will be true. I wanted to pass a
4:11:28message. This will be let's say server
4:11:30is running something like this. And then
4:11:33we are going to pass a data and this
4:11:35data will be let's say any data maybe
4:11:37let's say we are sending here routes and
4:11:41then maybe I'm just going to do this one
4:11:43as get/
4:11:45user something like this okay so now
4:11:47let's save this so it's simply calling
4:11:49this and now this is going to send your
4:11:51JSON response back okay so this is one
4:11:53so now what you're going to do right
4:11:55let's say I wanted to get this user
4:11:57information also so in that case what I
4:11:59can do I can create one more here so I'm
4:12:01just going to do if
4:12:03method is equal to get and if the path
4:12:08name is equal to / users. So in that
4:12:11case what I'm going to do is I'll copy
4:12:13this from here
4:12:16paste it. So uh this will be same and
4:12:19here I'm going to pass message and I
4:12:21will do user
4:12:23fed successfully and in the data I'm
4:12:27going to pass the users.
4:12:29this user is nothing but this data. This
4:12:33data we going to return. Okay. So now
4:12:36let's first of all let's check this and
4:12:38also at the end what I have to do right
4:12:41here after this I'm simply going to take
4:12:43another send JSON and I'm simply going
4:12:46to pass this one as null and when we are
4:12:49sending any request which route is not
4:12:52present. So we're going to pass a 404
4:12:54and in this case we're going to pass a
4:12:55success will be false. Message will be
4:12:58route not found
4:13:03and also you're going to do a error and
4:13:05this will be let's say this method
4:13:10and then you're going to pass this path
4:13:11name
4:13:13is not exist and then we'll go here and
4:13:17then just run this. So copy this,
4:13:21paste it, save,
4:13:24and then we'll just add it here. So I'm
4:13:27going to add one more. So this will be
4:13:2804. And this will be tsx source/ this.
4:13:33So save this.
4:13:35And now close this, clear it. And now
4:13:39this will be 04. So server is now
4:13:41running. So now let's go here. And I'm
4:13:43simply going to do 5003.
4:13:46So this will be get. And let's see first
4:13:48of all which uh what we are using here
4:13:50right. So we have this uh slash this
4:13:53path. So in this case we should get
4:13:55server is now running. So send this. So
4:13:58we're getting true message. We are
4:13:59getting the data. And now let's do this
4:14:02on / users. So in this case we should
4:14:04get the user here. We're getting 500
4:14:08error. Something we are doing wrong
4:14:10here.
4:14:14Oh we have to return from here man. we
4:14:16have to return. Okay,
4:14:18this is what we have to do. So let's
4:14:20save this.
4:14:22Clear it and run once again. And now
4:14:24let's try to send and you can see that
4:14:26you're getting the data here. So you're
4:14:28getting success to user is now fed
4:14:30successfully and you're getting the
4:14:32data. Okay. So now this is how you have
4:14:34to work with JSON. This is what we are
4:14:36going to use because once we start
4:14:38express this will make our life much
4:14:40easier because express will give some of
4:14:42the out ofthe-box features that we don't
4:14:43have to implement manually right. So
4:14:45with these four very very important uh
4:14:48topic that we have understood first of
4:14:51all basic HTTP server KSN routing
4:14:53concept reading body and then how you
4:14:57can work with JSON responses. So with
4:14:58this now let's move to the next one
4:14:59which will be our last concept for this
4:15:01particular uh section which will be how
4:15:04you can call external APIs and what is
4:15:06the best way to do that. Okay because
4:15:09calling external APIs is very simpler
4:15:10but you have to do some of the concepts.
4:15:13So let's see how we are going to do that
4:15:14in the next part. All right. So now
4:15:16let's end this particular section with
4:15:18another very important concept that how
4:15:20you can work with external API calls
4:15:22which is also one of the most frequent
4:15:25uh functionality that you can do. I not
4:15:27most frequent but yeah some of the times
4:15:28you are going to do this. Okay. So now
4:15:31so one of the most practical example
4:15:33will be let's say you are getting some
4:15:35task where you have to do some kind of
4:15:37web scrapping. Okay. Now in this case
4:15:39what you have to do right? So let's say
4:15:40you are going to have some external API
4:15:42and in first of all you're going to get
4:15:44the content. So you have to call that
4:15:46API right? And then let's say whatever
4:15:48content you're going to get you have to
4:15:49scrap the data something like this. I'm
4:15:51just giving a normal example or there
4:15:53can be like what we are going to do now.
4:15:54So you're going to have normal API call.
4:15:56You're going to get the response back
4:15:58and then let's say you're going to do
4:16:00something with that response and then at
4:16:02the end you're going to send the data
4:16:03back to your client. Okay. So first of
4:16:05all what we are going to do right we
4:16:07will be using this JSON placeholder API.
4:16:09This is very famous. Okay. And now if
4:16:12you notice one thing okay here. So
4:16:14notice that what are the format or
4:16:16things not format the properties that we
4:16:18are receiving here. So we have ID name,
4:16:20username, address, phone, website,
4:16:22company all these. So first of all what
4:16:24we are going to do right so let's say I
4:16:26have to actually call the data from this
4:16:28particular API only or I have to get the
4:16:30data. So what are you going to do right?
4:16:32So first I'm going to take this one as
4:16:33my API URL. Now one very very important
4:16:36concept I'm going to explain. Okay and
4:16:38this is going to be a game changanger
4:16:40for all of you. I'm not sure if some of
4:16:41you actually know this particular
4:16:43concept or not. So what I'm trying to do
4:16:45right so you notice one thing right when
4:16:48you are going to call the external API
4:16:50from a API source or from a URL or from
4:16:53a source you notice that that particular
4:16:56uh is going to give you the data in a
4:16:58certain format. So what I mean by this?
4:17:00So in this case you have a ID, name,
4:17:02username, address and then you're going
4:17:04to have street that is inside address.
4:17:06Similarly you have company and you see
4:17:07that you have name inside this company
4:17:10object. So that means this format
4:17:12actually provided by this particular
4:17:13API. But let's say in our application
4:17:17you need the data in a certain format
4:17:19and this is what we called as or I
4:17:21called as uh uh data trans
4:17:25transformation. Okay. So let's do this
4:17:27one with example or else this will be a
4:17:28little tricky. So what I'm going to do
4:17:30right I'm going to create one type and
4:17:31I'm just going to give this one as
4:17:33placeholder user. Why I'm giving
4:17:35placeholder user because this is the
4:17:37format that we are getting from this
4:17:39URL. So now in this one I'm going to get
4:17:42a number. Sorry ID which will be a
4:17:43number. Okay. So we have a id then we
4:17:45are going to get get a name right. So
4:17:47I'm just going to get a name. This will
4:17:50be what? String. Then we are going to
4:17:52get a email. So this also will be
4:17:53string. And now you see that we are
4:17:55going to get a company and then inside
4:17:57company you're going to get name
4:17:59correct. So now I'm just going to take
4:18:00this one as company and this particular
4:18:02company is going to have a name which
4:18:04will be string. Now this is only
4:18:06possible if you know the format of that
4:18:09external API right from where you are
4:18:10fetching the data. If you don't know in
4:18:12that case you have to use some unknown
4:18:13type and based on that you have to parse
4:18:15get the data. you're getting that what
4:18:17I'm talking about because in this case
4:18:18we actually know that okay this is the
4:18:20data format we are going to receive when
4:18:22we are going to call this particular API
4:18:23URL but now what I'm going to do right
4:18:26we are going we are not going to use
4:18:28this particular data set instead we are
4:18:30going to create our own data set so here
4:18:32I'm just going to do this one as public
4:18:35user okay and now what I need I need a
4:18:38number sorry ID which will be a number I
4:18:40need a name which will be another uh
4:18:43string I need a email which also will be
4:18:46string but in this case I don't need
4:18:49name inside company instead what I'm
4:18:51going to do right I'm going to get a
4:18:53company directly so that means this is
4:18:55my data format or this is the
4:18:57requirement of this application that I'm
4:18:59building and this is the data format I'm
4:19:01receiving from that APA okay so that
4:19:03means once I'll get the data I need to
4:19:05transfer this particular data to this
4:19:07particular format so in this case I hope
4:19:09this is you're getting right so what I'm
4:19:11doing here so now how we are going to do
4:19:13that to do this what we going to do
4:19:15Right? We need to create a function
4:19:16always here. Okay. So I'm just going to
4:19:18create a function and this is will be
4:19:20your transform data or you can do
4:19:22transform user because we are working
4:19:23with user here. Right? In this case now
4:19:27what will happen right? This will be
4:19:28your raw data. Now this raw data is
4:19:30nothing but the data that you are
4:19:32receiving from this URL. So the type
4:19:34will be this because this is the format
4:19:36you receiving from that particular data
4:19:38source. So this will be my placeholder
4:19:40user. But when we are going to return
4:19:43it, I need to return this in this
4:19:45particular format. So that means we are
4:19:47actually transforming the data here. So
4:19:49that means when I'm going to do I'll
4:19:50return ID which will be my raw data dot
4:19:53id. Then I'm going to return a name
4:19:55which will be my raw data dot name. Then
4:19:58I'm going to return a uh email which
4:20:00will be raw data. Sorry if you're
4:20:02getting any noise. I think it's coming
4:20:03from outside some bike. And then I'm
4:20:06going to return the company which will
4:20:07be raw data dot company dot name. So
4:20:11what we have done based on our
4:20:13application requirement we are changing
4:20:15the raw data into a certain format. Now
4:20:18this format can be anything and this
4:20:19format can be anything in case you don't
4:20:22know this particular format. So in that
4:20:23case you have to use unknown type right.
4:20:26So now I think this is done. So first of
4:20:28all what we are going to do. So first
4:20:30let's see the best way that we can do a
4:20:32API call. So here we are going to do
4:20:34fetch external user right. This is
4:20:36external API call. What will be the data
4:20:39uh return type? So return type will be a
4:20:41promise and this will be a void. So
4:20:43first of all what we have to do here now
4:20:46see you can directly use fetch okay but
4:20:50we have to use certain functionality
4:20:52here and that uh functionality we call
4:20:54as about controller. So what actually
4:20:56about controller is so first let me
4:20:58write it and then I'm going to explain.
4:21:00So this will be new about controller.
4:21:02Now you have to understand this one in a
4:21:04proper way. Now first of all this
4:21:06particular thing right whatever this is
4:21:09we don't know what actually this is so
4:21:10this is going to help us to cancel
4:21:14certain fetch request so this will be so
4:21:17let me put in a uh proper way so this
4:21:20will be about controller
4:21:22lets us
4:21:24uh cancel and in progress
4:21:28fetch request in progress fetch request
4:21:33okay Now when you directly use fetch
4:21:37right so let's say you are directly
4:21:38using fetch what will happen right fetch
4:21:40actually doesn't automatically fail
4:21:42let's say what will happen right maybe
4:21:44you are doing API call and that API call
4:21:45didn't give any response in first 10
4:21:47seconds that is possible right so in
4:21:49that case fetch will not help you to
4:21:51cancel that particular request here what
4:21:54you're going to do we are going to use
4:21:55something called this about controller
4:21:57and we'll see that how we are going to
4:21:58actually implement this one when your
4:22:00external API will become very slow in
4:22:03that case this can be very very helpful.
4:22:05Okay. So now uh what we are going to do
4:22:07right. So first of all what this is
4:22:09going to do? So this will gives us a
4:22:11signal. Okay. And we pass that signal to
4:22:14our fetch and then we use some method.
4:22:16So this will give you some method. For
4:22:18example about method and using that
4:22:21method that particular fetch that we are
4:22:23using that gets canled. So how we are
4:22:25going to do that? So first of all I'm
4:22:27going to get take a set timeout here and
4:22:30the oh no not not like this you have to
4:22:31take a timer so that so I'll just do a
4:22:34timer and here I'm just going to do set
4:22:36timeout
4:22:37and here what I'm going to do right I'll
4:22:39give a 5second time out here so what I'm
4:22:41simply doing right so first of all this
4:22:43timer is going to do what or set time is
4:22:45set timeout is going to do what this is
4:22:47going to start a timer now if your
4:22:50external API doesn't respond within 5
4:22:52seconds because we are giving 5 seconds
4:22:54here this will happen right This timer
4:22:56is going to do something but what
4:22:59actually it's going to do? So this is
4:23:00where we are going to use this
4:23:02controller.about method. Now now you'll
4:23:04see that this will be very clear. So
4:23:06what we are doing that okay first we are
4:23:08starting this then we are starting a
4:23:10timer and we are simply checking that if
4:23:12my API is not giving any request or
4:23:15response or pin inside 5 seconds I'm
4:23:18going to call this controller dotabout
4:23:20method. So this is going to do what?
4:23:22it's going to cancel that particular uh
4:23:25request. Okay, so this will be the first
4:23:26thing. After this what I'm going to do
4:23:29I'll take a try and here we are going to
4:23:31do actual call. So I'm just going to do
4:23:33con and I'm simply going to do this one
4:23:35as response and this is where I'll do a
4:23:38fetch.
4:23:40We going to pass the API URL and here we
4:23:43going to pass a method. So method will
4:23:45be get and here we are going to pass a
4:23:47signal and this will be controller dot
4:23:50signal. Okay. Now first of all what is
4:23:53happening here? What fetch is going to
4:23:55do? Fetch is going to send an HTTP
4:23:57request to this API URL right method is
4:24:00our gate. I I think this is very clear
4:24:02because gate means we are reading the
4:24:04data right. What this signal is so this
4:24:06is going to connect this particular
4:24:08request to this about controller above.
4:24:11This is going to do that. I hope this is
4:24:13clear. Right now what will happen right?
4:24:15If you notice that we are using this
4:24:17controller.abot method also. Right. In
4:24:20case this particular method controller
4:24:22that we are using that runs before this
4:24:25API response in that case fetch is going
4:24:28to throw an about error. Okay. So first
4:24:30what we have to do here? So first we are
4:24:32going to give a check okay that if this
4:24:34response do okay if this is false. So
4:24:36I'm just going to log error and let's
4:24:39give this one as uh upstream
4:24:43API field with HTTP and then we can pass
4:24:47the response right. So we do response
4:24:49dot status and then we are going to
4:24:53return. So this will be the first thing.
4:24:56Then we are going to get our data. So
4:24:58how we are going to get the data? So
4:24:59I'll do raw user and here we are going
4:25:02to do a because this is async operation,
4:25:06right? I think we are using async here
4:25:07if I'm not wrong. We are using async. So
4:25:10ait and this will be my response dot
4:25:12json. But here you have to give the your
4:25:14data format. So what will be your data
4:25:16format? how we are going to get the data
4:25:18in this particular format. So I'm just
4:25:20going to as placeholder user right and
4:25:23then we're going to transform the data
4:25:26in the format that we want means we want
4:25:28in this certain format. So that means we
4:25:30need to call this method. So now what
4:25:32I'm going to do right so I'm simply
4:25:33going to do con
4:25:35user and this will be my transform user
4:25:38and you're going to pass the raw user.
4:25:40That's it. And now what I'm going to do
4:25:41right I'll simply just do log and I'm
4:25:44just going to log the user and then
4:25:46we'll take a catch.
4:25:48Let's take a error. Now what are we
4:25:51going to do first of all? So first I'm
4:25:53going to check if this error is a
4:25:55instance
4:25:59if this instance of error
4:26:02and if the error dot name
4:26:06is equal to okay we have to give equal
4:26:08to and this we called as about error
4:26:12okay and let's just check this one here
4:26:16so first of all I'm just going to do
4:26:18what is about error
4:26:23This is a specific error thrown in
4:26:25JavaScript when an ongoing asynchronous
4:26:27is deliberately cancelled. Okay. So
4:26:30first of all why does it happen? Most
4:26:32JavaScript APIs use about controller
4:26:34about signal interfaces to manage
4:26:36cancellation. When you invoke this about
4:26:39that we are doing here right simply we
4:26:41are calling this controller.about. So
4:26:43that means what will happen right? If
4:26:45your time out this particular timeout if
4:26:47this is runs and this particular about
4:26:49method is canceled sorry not canceled if
4:26:51called. So in that case your fetch is
4:26:53going to do is going to throw an error
4:26:56that error called as about error. Okay.
4:26:59So this is the task of your fetch but
4:27:01this will only throw in case if you're
4:27:03calling this and then you're passing the
4:27:05signal here. Okay. This is very very
4:27:07important. So now what are you going to
4:27:09do right? So first of all I think this
4:27:12is clear right or let's see if we know
4:27:14okay let's see common operation that
4:27:15trigger this canceling an ongoing f
4:27:18request stopping a read or write
4:27:20operation on streams and some
4:27:22interrupting and database query but for
4:27:24now we are focusing only on this one and
4:27:25this is what actually we are doing here
4:27:27right so we are simply telling that okay
4:27:29if this timeout fails so in that case
4:27:31you're going to call the about method so
4:27:33in that case your fetch is going to
4:27:34throw that about error so now what are
4:27:36you going to do right so first of all if
4:27:38this is the case So in that case I'm
4:27:40just going to do error again
4:27:44and I'm just going to do request failed
4:27:47or time out whatever you are going to do
4:27:49because
4:27:51upstream
4:27:52API took so long something like this and
4:27:57[snorts] we are going to return okay so
4:27:59this is done and then we are going to
4:28:02simply do we are also going to take a
4:28:04message and I'm simply going to do if
4:28:06the error is instance is
4:28:10of error. So we are going to get the
4:28:13error dot message or else I'm just
4:28:15simply going to pass unknown error.
4:28:19Okay. And then also again we can log
4:28:21error and I'm simply going to do
4:28:23external
4:28:26API failed
4:28:29and then we're going to pass this
4:28:30message here and then we are also going
4:28:33to take a finally. So in the finally
4:28:35what we have to do we have to clear the
4:28:37time out because we have a timeout here.
4:28:40So I'm just going to do clear time out
4:28:41and pass the timer and timer what we are
4:28:44using here. We're using timer only
4:28:47right? I think let's skip maybe let's
4:28:50skip time out. I think time out is
4:28:51better.
4:28:54And we're going to clear this here.
4:28:56Okay. That's it. So now I think this is
4:28:58done. So what we have to do right? So
4:29:00let's save this. And to call this, we
4:29:02are simply going to call this method
4:29:03here.
4:29:05That's it. So, this is done. So, now
4:29:07let's save this. And I'm just going to
4:29:10close. Let's clear. And I'll just copy
4:29:14this. Let's go to package.json.
4:29:17And I'll just paste it here. So, this
4:29:19will be 05
4:29:21tsx source/
4:29:24this. And then we're going to just run
4:29:26this. I'll do npm run 05.
4:29:30That's it. So you're going to get error
4:29:32not get error you're going to get the
4:29:33data because definitely it's going to
4:29:35pass. Now in this case one thing you
4:29:37have to understand that even though your
4:29:38response of this particular API is in
4:29:41this format that you are having company
4:29:43and inside company you are having name
4:29:45but when you're getting the actual data
4:29:46you're getting company as this directly.
4:29:49Okay this is very important why because
4:29:51in our code we are actually formatting
4:29:53or transforming the data the way we want
4:29:56you're getting. So this is what actually
4:29:58it's doing. So this is very very helpful
4:30:00when you have some certain requirement
4:30:02in your project and you want to
4:30:04transform the data. So you can use this
4:30:05kind of uh uh features. So I this is
4:30:09clear. I think this is very important.
4:30:10So with this we have completed one very
4:30:12important and I'm pretty much sure see
4:30:14if you're a beginner or let's see even
4:30:15the intermediate level this is more than
4:30:17enough in your node HTTP module. Right?
4:30:19Again when I'm going to create the part
4:30:21three in case if I'm getting good
4:30:23response I always mention that or else
4:30:24I'm not going to do that. I'll be very
4:30:26honest. If I get good response from part
4:30:28one and two and you'll see that there
4:30:30are certain concepts that normally you
4:30:32not find in most of the courses or
4:30:34videos those I'm going to cover but for
4:30:36now I think this is more than enough. So
4:30:38with this what will be the next part see
4:30:40I'm going to repeat once again again and
4:30:42again and I'm telling you so that you
4:30:45find sorry not you find or you actually
4:30:48get the most advantage from this
4:30:49particular video. What I'm trying to say
4:30:51is very very important that I'm going to
4:30:53add my posgress full course that I
4:30:55already created. This is very recent
4:30:57course like I think maybe one month ago
4:31:00I uploaded. I'm going to add that in the
4:31:02next part. Please do not skip that
4:31:04particular section. Okay. You can skip
4:31:06the intro part. Why I'm telling because
4:31:08that is a video part right? You can skip
4:31:10the intro like it will be 1 minute or
4:31:12even you can watch the intro because
4:31:14you'll understand that what are the
4:31:15things you are going to learn. Why this
4:31:16is very very important because this next
4:31:194 hours is going to give you exact idea
4:31:22of posgress every single thing you need
4:31:24and remember we are not going to use any
4:31:27packages in that so we are not using any
4:31:28OM prisma or drizzle okay these kind of
4:31:31things we are going to use raw pg and
4:31:33this is going to be a game changanger
4:31:35because if you really want to learn
4:31:36postless and then you start the API
4:31:38project that we are going to have after
4:31:39that so what I'm trying to say I'm going
4:31:42to repeat once again that do not skip
4:31:44this particular section okay this part.
4:31:46Do not skip. First you learn this one
4:31:49and after this you try to complete this
4:31:51whole section without skipping any any
4:31:53concept and then you do this then you
4:31:56jump to this one you already have the
4:31:58time stamp right you can directly jump
4:32:00in case you already know then you can
4:32:03directly jump to this particular section
4:32:05but I suggest do not do this one okay so
4:32:07with this now let's move on to the next
4:32:08one which will be postgress complete
4:32:10course and then we will start our actual
4:32:12practical project and in this one you're
4:32:14going to learn each and everything uh
4:32:16that you need to know to start your
4:32:18practical journey with node. Okay
4:32:21everyone, so now before uh we are going
4:32:23to proceed to our next section which
4:32:25will be so as I already mentioned that
4:32:27in the previous section we have
4:32:28completed HTTP and then we are going to
4:32:30have a complete dedicated postgress
4:32:32section but before that I thought that
4:32:34let's uh cover some of the very
4:32:35important uh concept and now these will
4:32:37be little bit advanced if you want you
4:32:39can watch this particular section or
4:32:41else you can also skip it's up to you
4:32:43because this will be mostly concepts and
4:32:45also we going to understand some of the
4:32:47nodes internals okay so first of all So
4:32:50how we are going to do this one right?
4:32:51So we are going to create one one file
4:32:53and then we'll go to uh this uh flow and
4:32:56then we are going to understand that
4:32:58what actually happening here and most of
4:33:00the things you can also get in your
4:33:01interview also. So first let's start
4:33:04with so let's create our first file and
4:33:06let's give this one as NodeJS
4:33:09internals. Okay. Now in the previous
4:33:11part we have already covered that what
4:33:13actually NodeJS is right. So we already
4:33:15know that NodeJS is a JavaScript
4:33:16runtime.
4:33:18But what we need to know that node is
4:33:21actually combines multiple components.
4:33:23So what I mean by multiple components?
4:33:25So we have something called V8 right. So
4:33:28we have something called V8 engine
4:33:30right. So what actually V8 engine is
4:33:32actually going to do. So this is what
4:33:34actually executes your JavaScript right.
4:33:36So this is the very basic things right.
4:33:38But we have also covered in the previous
4:33:41section that NodeJS also has some code
4:33:43modules also. For example let's say
4:33:44NodeJS has something called FS file
4:33:46system. NodeJS has networking, NodeJS
4:33:48has timers and all these things. What
4:33:51actually happens right? So there are a
4:33:53couple of things you need to understand
4:33:54that how actually NodeJS run your code.
4:33:56That is the most important part here
4:33:58which is what we are going to cover. So
4:34:00here we need to know first of all that
4:34:02NodeJS actually more than V8 engine is
4:34:05there are lot of things that is
4:34:06happening behind the scenes. So first of
4:34:08all what we going to cover? So some of
4:34:10the things you need to know that is
4:34:11first of all that what are the main
4:34:12NodeJS runtime components that we have.
4:34:15So first we have something called very
4:34:17very important and that we call as main
4:34:20JavaScript. So I'm just going to give
4:34:22main JS thread. So what this is going to
4:34:24do now first of all you need to know
4:34:27that whenever you're going to create a
4:34:28normal application right what JavaScript
4:34:30is going to do JavaScript execute one
4:34:33particular main JavaScript thread or
4:34:35JavaScript execute on one main
4:34:38JavaScript thread. Sorry I was explained
4:34:40that one wrong. So the this will be so
4:34:42normal applications. I'm just going to
4:34:44do like this. Normal applications
4:34:46JavaScript executes on one main
4:34:50JavaScript thread. Okay. So what I mean
4:34:53by this? So what are the process
4:34:55actually? So here you have your top
4:34:56level JavaScript, right? So let's say
4:34:58you have a function. So you have your
4:34:59top level JavaScript, you have your
4:35:01function call, you have your request
4:35:03handlers, you are going to have your
4:35:04timer. So let's you are using set
4:35:05timeout, set interval, all these. You
4:35:08have your promise call backs, file
4:35:09system call backs and all these things,
4:35:11right? So that means only one normal
4:35:13JavaScript call back execute at a time
4:35:15on this particular thread and this we
4:35:17call as main JavaScript thread. Right?
4:35:19And then the second main component will
4:35:22be your V8 engine. So what actually this
4:35:24V8 engine uh does. Okay. Now first of
4:35:28all you need to know that V8 is the
4:35:30JavaScript engine that is used by
4:35:32NodeJS. Okay. So V8 will be your
4:35:34JavaScript engine that is used by
4:35:36NodeJS. What this is going to do or what
4:35:38are the main responsibilities? First of
4:35:40all, it is going to do parsing your
4:35:42JavaScript. So, it is going to parse
4:35:43your JavaScript. So, parsing JS, it's
4:35:46going to execute your JavaScript. This
4:35:48will be the second thing. This is going
4:35:50to manage your call stack. So, managing
4:35:52call stack.
4:35:54Next will be it's also going to manage
4:35:56your heap memory also. Heap memory.
4:36:00Okay.
4:36:02And he memory and performing
4:36:06garbage collection.
4:36:10Okay.
4:36:12And also sometimes it's going to do
4:36:14what? It's going to optimize your
4:36:15executed code also. But mostly you need
4:36:17to know that these three are very very
4:36:19important. So first of all it's actually
4:36:21going to parse your JavaScript. It's
4:36:22going to execute your JavaScript and
4:36:23it's going to manage your call stack.
4:36:25Okay. So this is another main core
4:36:27component. So we have main JavaScript
4:36:29thread and then we have your V8 engine.
4:36:32Now we have right so we have our NodeJS
4:36:34core API. Now you might be thinking okay
4:36:36we have already covered but this is
4:36:37still very important because now we are
4:36:39actually understanding what is happening
4:36:40behind the scenes right so we have your
4:36:42NodeJS code APIs when I'm talking about
4:36:44what actually NodeJS code APIs are the
4:36:47things that we have already covered for
4:36:48example our file system we have our HTTP
4:36:50module we have our path module we have
4:36:53our streams right so all these things we
4:36:55have covered buffers then you have
4:36:57process right process also we have
4:36:59covered then you have timers all these
4:37:01things now all these core APIs right
4:37:03whatever you're seeing these actually
4:37:05written in JS only. Okay. Now some of
4:37:10these okay some of these core EPS next
4:37:13you have something called C++. So I'm
4:37:15just going to give it comment. So do C++
4:37:18bindings. Okay. Now what this is going
4:37:21to do now first of all you have to
4:37:22understand that what this is going to
4:37:24do. This is going to connect your
4:37:25JavaScript facing NodeJS APIs to native
4:37:28functionality. Okay. So that means here
4:37:30so first of all let's write it. So it's
4:37:32going to connect JS facing APIs to
4:37:37native functionality.
4:37:40So here what this is going to do right
4:37:41it's going to allow your JavaScript code
4:37:44to communicate to communicate with so we
4:37:49have something called leu okay then we
4:37:52have something called our operating
4:37:53system so OS APIs your native libraries
4:37:57okay now if I try to cover this leu only
4:38:01right so it's going to take more than 2
4:38:03hours okay so there are a lot of things
4:38:05so that is the reason I'm just going to
4:38:07give you the overview but when I'm going
4:38:08to upload the part three possible if I'm
4:38:11getting good response from this part one
4:38:13then I'm going to upload part part two
4:38:14anyways I'm going to upload but part
4:38:16three if I upload so I'm going to cover
4:38:18all of this in details okay now why
4:38:20actually you need all of this because
4:38:21what JavaScript is going to do right
4:38:23JavaScript doesn't directly call this
4:38:25operating system level kernels okay here
4:38:28this is one of the most important
4:38:30JavaScript core component that you need
4:38:31to know if you want to learn NodeJS uh
4:38:34properly now this is actually a native
4:38:36library that is used by NodeJS okay so
4:38:38this is a native library that is uh used
4:38:42by NodeJS used by NodeJS. So what this
4:38:46is going to provide right so it's going
4:38:47to first of all provide your event loop
4:38:49then it's going to provide your worker
4:38:51thread worker thread pool your timers
4:38:56your asynchronous as IO input output
4:38:59handling
4:39:01and also sometimes uh crossplatform
4:39:04abstractions all these things right here
4:39:06so first of all four things we have
4:39:08understood right so we have something
4:39:10called our main JS thread our VS sorry
4:39:12V8 engine nodes code APIs we have C++
4:39:16bindings and one very important native
4:39:19module sorry native library that we call
4:39:21as li okay then we have our operating
4:39:24system now all these are actually nodes
4:39:26internals okay you'll understand why I'm
4:39:28explaining all of these so you your
4:39:29operating system OS what operating
4:39:32system is going to do I think we have
4:39:34already covered the OS model remember
4:39:35operating system is going to do your
4:39:37low-level work so low-level work means
4:39:40let's say reading your files reading
4:39:41files writing your files
4:39:45uh maybe let's say tracking time
4:39:48right so all these thing it's going to
4:39:50do so now let's say if I go here and if
4:39:53you try to understand this one right so
4:39:55you have your javascript code this is
4:39:57your v8 engine and these all your core
4:40:00components so you have your nodejs core
4:40:02APIs which interact with your C++
4:40:04bindings right and this this is actually
4:40:06C++ binding is going to do what so C++
4:40:09binding is going to connect your
4:40:10JavaScript facing nodejs core APIs this
4:40:13on. So you have a JavaScript facing
4:40:14NodeJS API to your native functionality.
4:40:16So this C++ binding is going to help to
4:40:20communicate this particular API to your
4:40:23Leo this library or your operating
4:40:25system library. Okay. So this is why
4:40:26this C++ binding is actually very
4:40:29important. So I'm just going to repeat
4:40:30once again why this is actually very
4:40:32important. So have your JavaScript code.
4:40:34So first of all you have to understand
4:40:36what VS sorry V8 engine is going to do.
4:40:38So V8 engine actually going to parse
4:40:41your JavaScript. So that is the first
4:40:42thing. It's going to execute your
4:40:43JavaScript. It's going to manage your
4:40:45call stack. Okay. But then you have your
4:40:47some code API. I think we've already
4:40:49covered code modules, file system, uh
4:40:51HTTP, timers, all these things. But the
4:40:53problem is this code some some of these
4:40:56core APIs actually written in
4:40:57JavaScript. So it's actually can't
4:40:59directly interact with your operating
4:41:01system, right? So that is the reason we
4:41:03need something called or we need some
4:41:05mediator and that we call as C++
4:41:07bindings. So C++ bindings is going to
4:41:10connect your JavaScript facing nodes
4:41:12APIs to the native functionality. So
4:41:14this native functionality will be your
4:41:15native libraries leave and operating
4:41:18system. What leop is going to do? So
4:41:20this is a native library that is used by
4:41:23nodejs. It's going to provide your event
4:41:24loop, worker thread, timers and all
4:41:26these things. And operating system is
4:41:28going to do your low-level work. So
4:41:30low-level work means it's going to do
4:41:32let's say reading your files or writing
4:41:34files uh tracking time let's say it
4:41:37needs to needs to schedule some threads
4:41:39and all these things is going to do okay
4:41:41you need to know one very important
4:41:43thing that NodeJS is going to
4:41:45coordinates all these work but at the
4:41:46end your operating system is going to
4:41:48process actual system operations you are
4:41:51getting what I'm talking about so these
4:41:53all are very very important so if I try
4:41:54to explain this one let's say so you
4:41:56have your JS code right so this is your
4:41:58JS code. Then you have your V8 engine,
4:42:01right? And then you have your JavaScript
4:42:04code. So your JS code,
4:42:07then you have your NodeJS core APIs. So
4:42:10do core APIs. You have your
4:42:14you have your C++ bindings.
4:42:18Then you have your LIV and then you have
4:42:22your operating system. So this is how
4:42:24it's going to work. Okay. So this is the
4:42:26overall flow. Now this is very top level
4:42:28but if you try if someone ask you okay
4:42:30give me or let's say they will ask you
4:42:32in the interview okay give me summary of
4:42:34that how actually NodeJS internal flow
4:42:36works. So just explain in this way that
4:42:38first operating system is going to start
4:42:40your NodeJS process right. So NodeJS is
4:42:43going to initialize your V8 engine. So
4:42:44it's going to initialize your V8 engine.
4:42:47NodeJS also initialize your LEU and the
4:42:49event loop. Okay. Now let's say you have
4:42:52an entry file. I think we already know.
4:42:53So entry file is let's say app.js,
4:42:55right? So what NodeJS is going to do?
4:42:56It's going to load your app.js file.
4:42:58Right? Then V8 what it's going to do? V8
4:43:02is going to parse and execute your
4:43:03JavaScript. Right? V8 is going to parse
4:43:06and execute your JavaScript. Then your
4:43:08top level JavaScript is going to run on
4:43:10your main thread. I already explained
4:43:12this main thread, right? Normal
4:43:13JavaScript is going to run on the main
4:43:14thread. Once this is done, then let's
4:43:17say you have some async operation. Maybe
4:43:18let's say you're doing some API call. So
4:43:20async operation will be registered or
4:43:22delegated whatever it's going to do.
4:43:24Then the very important point you have
4:43:26something called event loop. Now I'm not
4:43:28going to go into too much details into
4:43:29event loop because it's very vast topic
4:43:31and then probably I'm [clears throat]
4:43:33going to cover this one in the part
4:43:34three okay not this one but event loop
4:43:37is going to continue until unless there
4:43:38is active work okay and then let's say
4:43:40you have some callbacks so comp all the
4:43:42callbacks will be completed and those
4:43:44call backs will be executed on your main
4:43:46thread okay so main thread will be your
4:43:48active and this process is going to exit
4:43:51when there is no active work remains
4:43:53means until unless there is active work
4:43:55your main thread will remain active
4:43:57Okay. So this will be your overall flow
4:43:59or this is how your NodeJS internal
4:44:01process works. So what are the things
4:44:03you need to know right? Why I'm
4:44:04repeating all of these? So first you
4:44:05need to know the term called we have
4:44:07something called VS sorry main JS
4:44:08thread. We have something called V V8
4:44:11engine. We have our NodeJS code APIs. We
4:44:13have C++ binding. What this is going to
4:44:15do? We have something called Leo and
4:44:18then we have our operating system. So
4:44:20with this now let's move on to the next
4:44:22concept. So let's move to the next
4:44:23concept and this will be so let's
4:44:25understand V8 uh V8 engine in details.
4:44:29Okay. So V8 engine MD. So I think we
4:44:33already know the basics right that what
4:44:34actually V8 engine does. So V8 will be
4:44:37your JavaScript engine. So V8 uh is your
4:44:40JavaScript engine that is used by used
4:44:45by NodeJS. Correct? So we already know
4:44:48the responsibility not KS it will be JS
4:44:51already know the responsibility it's
4:44:52going to parse your JavaScript it's
4:44:54going to let's say sorry it's going to
4:44:55parse your JavaScript so we are going to
4:44:57go into much more details now in this
4:44:59particular file and then we understood
4:45:01in the previous section that it's going
4:45:02to parse your JavaScript it's going to
4:45:03execute your code it's going to handle
4:45:05your event loop and all these things but
4:45:07how actually this whole process works or
4:45:10means what actually happens behind the
4:45:12scenes so [snorts] first let's
4:45:14understand that how V8 actually uh
4:45:16execute the JavaScript. Now this is very
4:45:18very interesting concept. Okay, what
4:45:20this is going to do, right? So first of
4:45:22all, it's going to parse your
4:45:23JavaScript. Okay, so this is the first
4:45:24thing once it will parse your
4:45:26JavaScript, right? So what this is going
4:45:28to do, right? This is going to create a
4:45:29internal representation of your code. So
4:45:32what I mean by this? So basically it's
4:45:34going to produce something called byte
4:45:36code. So it's going to produce byte
4:45:38code. So it's going to produce byte code
4:45:41and then it's going to execute the code.
4:45:43So then it's going to execute the code
4:45:45and then I'm just going to let's write
4:45:47it here only. So first of all we know
4:45:49that it's going to parse your JS. It's
4:45:51going to create internal representation
4:45:52of your code that what actually that
4:45:54code is doing. It's going to produce the
4:45:56bite code. It's going to execute the
4:45:57code right and then as you already me
4:46:00mentioned in the previous section also
4:46:01sometime it's going to optimize your
4:46:03frequent used code also. Then it's going
4:46:06to manage your call stack. So all these
4:46:08things it's going to do. This is not uh
4:46:11let's keep this one here in the new
4:46:13line. So it's going to manage your call
4:46:14stack. It's also manage your hip memory
4:46:18all these thing it's going to do right
4:46:19and also garbage collection also it's
4:46:21going to perform garbage collection.
4:46:24So all these thing your V8 engine is
4:46:26going to do. So now let's understand
4:46:29here that what actually it is doing. So
4:46:31first you have your JavaScript source
4:46:33correct. So this is your JavaScript code
4:46:35and then you have some you have
4:46:37something called parser. So this is
4:46:39where your V8 is going to parse your
4:46:41JavaScript right. So that means see
4:46:44first of all you need to know that what
4:46:45actually mean by parse the code mean V
4:46:49V8 engine needs to understand the source
4:46:51code right that what actually you're
4:46:53writing. So sometimes consider that you
4:46:55have something like this you have con
4:46:58total equal to price plus tax something
4:47:00like that you have written. So V8 is
4:47:02going to read that and it's going to
4:47:04check the syntax. If the syntax is
4:47:07invalid, so it's not going to run the
4:47:09code, right? So for example, let's say
4:47:11you written const total equals and then
4:47:15you don't have anything on the right
4:47:16side. So this is wrong. Correct? So that
4:47:18means this person is going to check the
4:47:20syntax and based on that it's going to
4:47:22give a error that if the statement is
4:47:24incomplete, right? After this it's going
4:47:27to create something called abstract
4:47:29syntax tree. Now you might be thinking
4:47:31from where I've actually learned all of
4:47:33these. So these all the things right
4:47:35what you can do right I'll give you the
4:47:37best of the best solution. So first
4:47:39option will be you search for uh V8
4:47:42engine internals or how V8 engine works
4:47:44on Google not on chat GP and everything.
4:47:46Okay. And then read some blogs. The
4:47:49blogs I'm talking about the old blogs.
4:47:51Old blogs means when this chat GP and
4:47:53all these things uh was not there. Okay.
4:47:55and then read some two three blogs and
4:47:57try to understand and then [snorts] you
4:47:59can ask for some AI tools and
4:48:00everything. So this is why I usually
4:48:02read multiple blogs and then I came to
4:48:04know all these things and based on this
4:48:05I actually created and try to simpl
4:48:07simplify this particular flow. So what
4:48:09this is going to do right after pursing
4:48:11it's going to create a abstract syntax
4:48:13tree and this we call as a insert. Okay.
4:48:16So this is what it's going to do that
4:48:18means this is going to represent that
4:48:20what actually you have written in the
4:48:21code. As simple as that what actually
4:48:23you have written in the code means it's
4:48:24going to understand your structure and
4:48:26the meaning of the program. For example
4:48:28let's have a cons total is equal to
4:48:30price plus tax. So it's going to
4:48:31understand okay you are creating a total
4:48:32value from price and tax. So you're
4:48:34adding both right. So here it's going to
4:48:37understand okay I have a variable
4:48:39declaration which is total uh I have a
4:48:42addition so I'm adding both price and
4:48:44tax so it's going to understand so this
4:48:46particular part is going to understand
4:48:47that code okay so now what this is going
4:48:50to do right and also okay one very
4:48:52important point when this is going to
4:48:53check right so it actually going to
4:48:55remove unnecessary formatting details
4:48:57and everything okay for example let's
4:48:58say you have spaces indentation all this
4:49:01thing is going to remove once this is
4:49:02done then it's going to create your bite
4:49:04code okay so this will be your bite code
4:49:06we also call as bite code and the
4:49:09interpreter. Okay. So, V8 is going to
4:49:11create the bite code. I already
4:49:12mentioned it's going to produce the bite
4:49:14code. Why? First of all, you need to
4:49:16know what actually bite code. So, it's a
4:49:18low-level or lower level internal format
4:49:21and this is actually easier to
4:49:23understand actually for V8 because at
4:49:25the end V8 is going to execute your
4:49:27code, right? So, that is the reason what
4:49:28this is going to do. It's going to
4:49:29actually produce a bite code. Once this
4:49:32is done, then we have something called
4:49:34interpreter. Okay? So interpreter and
4:49:36then you have your optimize. I think
4:49:37this part you can understand easily. So
4:49:39optimize I mentioned this one right. So
4:49:41sometime is going to optimize your
4:49:42frequent written code. So it's going to
4:49:44optimize your machine code and then at
4:49:46the end it's going to execute the code.
4:49:47But the main important part actually
4:49:49these three line here. So first you have
4:49:51a parser. What parser is going to do?
4:49:53Parser is going to check your syntax.
4:49:54That is very important. If you have a
4:49:56wrong wrong syntax it's going to give
4:49:58you error. Right? So then you have
4:50:00something called abstract syntax tree or
4:50:02a So this is going to do what I already
4:50:05mentioned. So this is going to create or
4:50:06this is going to represent the structure
4:50:08or the meaning of your actual code means
4:50:10this is going to understand let's have a
4:50:12function okay this is a function this is
4:50:14the name of the function this function
4:50:15is adding two variables and it's going
4:50:17to return the sum of these two
4:50:18variables. So this is going to
4:50:19understand that and based on that it's
4:50:21going to produce a bite code and then
4:50:23it's going to create uh sorry it's going
4:50:25to execute your code. Okay. So this will
4:50:28be the overall flow or this is how V8 is
4:50:31going to execute your JavaScript uh code
4:50:34or NodeJS code. Okay. So I think that's
4:50:36all for this particular one. Now with
4:50:38this now let's move on to the next one.
4:50:39So let's move to the next one. I thought
4:50:41that I'm not going to cover but let's
4:50:43give you some idea on this particular
4:50:44module. Okay. So what actually this
4:50:46library does I'm doing TSM.
4:50:52Okay. So first of all we already know
4:50:54that that Leo
4:50:56is a native library that is used by
4:51:00NodeJS right so this we already know. So
4:51:03first what is the main purpose? So the
4:51:06main purpose will be so you have to
4:51:08understand this one. So this is actually
4:51:09going to help node to handle
4:51:12asynchronous or async operations right
4:51:15across different OS system also this is
4:51:17very important. So when I what I mean by
4:51:19this so first let's write it. So it's
4:51:21going to help. So it's going to help
4:51:23NodeJS to handle
4:51:25a sync operations
4:51:29across
4:51:31different OS
4:51:33system. Okay. So here this is going to
4:51:36provide first of all in event loop
4:51:38worker thread pool
4:51:42in your timers right uh async io
4:51:46operations.
4:51:49So now let's understand that why
4:51:51actually NodeJS need this particular
4:51:53library. Now what we understood from the
4:51:56previous section that what V8 actually
4:51:58going to do. So V8 is going to execute
4:52:00JavaScript right. So it's going to
4:52:02execute a JavaScript code. It's going to
4:52:03create you it has some parser. It's
4:52:06going to parse your code. It's going to
4:52:08create a right as we have already
4:52:10covered that one. Then based on that
4:52:12it's going to produce produce the bite
4:52:13code and based on that it's going to run
4:52:15your code. But V8 actually not going to
4:52:18provide all these operations. So it's
4:52:20not going to provide. So V8 does not
4:52:23provide
4:52:25file system operations.
4:52:29Then you have network
4:52:31socket handling all these things
4:52:36right and then also
4:52:40uh general event loop for node APIs,
4:52:43NodeJS APIs, right? So that means in
4:52:45this case NodeJS needs something else to
4:52:49handle all this. So NodeJS needs
4:52:50something else. Correct? So this means
4:52:53NodeJS need a separate layer or NodeJS
4:52:57needs a another layer that will handle
4:53:01uh that will handle not handle but that
4:53:03will coordinate
4:53:05coordinate
4:53:07this runtime because all these are
4:53:09runtime features right. all these
4:53:10runtime features right and all these
4:53:13features are provided by this leuof
4:53:15native library okay so this is what it's
4:53:17going to do if we try to explain uh
4:53:19understand this one so before we'll
4:53:21explain this so let's see this one so
4:53:22you have something like this you have
4:53:24your NodeJS API so I'll do NodeJS APIs
4:53:27right and then you have your JavaScript
4:53:30code you have NodeJS APIs you have your
4:53:32uh then you have your native binding
4:53:35then you have your leave and then at the
4:53:37end you you're going to have your OS
4:53:39right so This is how it's going to do.
4:53:41So first of all let's see this
4:53:43particular flow and then we understand
4:53:44the responsibilities. So you see that we
4:53:47have JavaScript uh then you have your
4:53:49NodeJS code APIs the code AP we have
4:53:51file system HTTP timers and all these
4:53:53things then it will go through your CS C
4:53:55C++ binding I think this is the same
4:53:57flow we covered then we have your leave
4:53:59of uh library right so it's going to
4:54:01provide all this thread pool event loop
4:54:03and everything and at the end it's going
4:54:05to interact with your operating system.
4:54:07So this is what it's going to do and
4:54:08what these uh main responsibilities will
4:54:10be. So first of all event loop right? So
4:54:12what actually event loop is going to do?
4:54:14I'll give you basic overview. So what
4:54:16event loop is going to check for? See
4:54:17event loop is going to check for a
4:54:18couple of things. First it's going to
4:54:20check for your completed IO operations.
4:54:22It's going to check for a timer. So
4:54:24let's say you are using some timers and
4:54:25it's going to check whether there is any
4:54:27timer which is in ready state. It also
4:54:30going to check for your pending
4:54:31callbacks and also it socket activity.
4:54:33Okay. So socket means let's say you're
4:54:35using sockets. So event loop is also
4:54:37going to check the activity
4:54:38[clears throat] of that particular
4:54:38socket. So now I'm just going to write
4:54:40here. So what event loop is going to
4:54:42check? So it's going to check for your
4:54:44completed IO operations.
4:54:48It's also going to check for your
4:54:49timers. So if you have any timers and if
4:54:52some timers
4:54:56timers are in ready state
4:55:00then you also want to check for your
4:55:01pending callbacks. Also it's going to
4:55:04check for the socket
4:55:06activity. So this is what event loop is
4:55:09going to check or this will be one of
4:55:12the main responsibility of libu which
4:55:14will provide this particular feature.
4:55:17Then second will be we have something
4:55:18called thread pool. Right? So we have
4:55:20something called thread pool. Why
4:55:22actually we need thread pool or why liu
4:55:24actually provide this particular thing.
4:55:26So first of all you need to know that
4:55:27libu provides
4:55:30provides a shared worker thread pool
4:55:35and why actually you need this. Now if
4:55:37you go here this particular thing I'm
4:55:39talking about this thread pool or this
4:55:41pool is is used by those operations that
4:55:45cannot be handled efficiently. Now what
4:55:47I mean by this? So that means this pool
4:55:49that we have is used by only those
4:55:54operations
4:55:56that cannot be handled efficiently. Now
4:56:00the best example of this will be let's
4:56:02say you have some project you're
4:56:04building some project where you have
4:56:05multiple or many file system operations
4:56:09many file system operations. Okay then
4:56:12let's say you are doing some
4:56:14cryptographic operations. So this is
4:56:15also where it's needed cryptographic
4:56:17operations and then also let's say
4:56:19you're using some compression related
4:56:21work.
4:56:24Okay. So this is where we need this
4:56:27thread pool and then also you have
4:56:29something called timers right. So timer
4:56:30is nothing but so what li is going to do
4:56:32it's going to help node to track all
4:56:34those timers right and then very very
4:56:37important it's going to determine when a
4:56:39particular timer is eligible to execute.
4:56:41Okay. So that means let's say you have a
4:56:43timer with a delay. What will happen?
4:56:45Right? It doesn't going to block your
4:56:48JavaScript main thread. Okay. So I think
4:56:49this part we already covered what this
4:56:52runtime is going to do, right? Runtime
4:56:54is going to record that particular timer
4:56:56and then it's going to continue
4:56:57processing the other task. Okay. So this
4:57:00is actually very important concept.
4:57:01Okay. So let's say you have a timer. So
4:57:03li is going to help lies
4:57:06to track those timers.
4:57:10And then this is important part. So this
4:57:12is the important here. So it's going to
4:57:14determine when the timer is become
4:57:19eligible to run or no not run execute.
4:57:23Right? So what will happen right? So
4:57:24let's say you have a timer with 5second
4:57:26delay. So a 5second delay. So it not
4:57:29going to or this doesn't mean so it
4:57:32doesn't mean the javascript is going to
4:57:35slip on the main thread. It's not going
4:57:37to do that. So it's going to do what?
4:57:38Right. So this uh timer whatever you
4:57:41have runtime is going to runtime is
4:57:45going to record this timer that okay I
4:57:46have a timer. So runtime is record the
4:57:49timer and then it's going to continue
4:57:51working other task. So continue
4:57:53processing other task and then once this
4:57:56timer is become eligible to execute so
4:57:58that time li is going to determine and
4:58:00based on that it's going to run the
4:58:01timer on the main thread. Okay. So this
4:58:04is what it's going to do and also li
4:58:06also communicate with your operating
4:58:08system APIs right. So this part let's
4:58:10say file related operations handle uh
4:58:12process handling timing as synchronous
4:58:14notification and all these things. So
4:58:16this is why we need this particular
4:58:18module which we call as leave. So with
4:58:21this now let's move on to the next
4:58:22concept. Okay. So let's move to the next
4:58:24one. Uh and these will be so let's
4:58:26understand what is uh blocking
4:58:31and non-blocking.
4:58:34Now you might be thinking I'll tell you
4:58:36why actually I'm covering all these uh
4:58:37this section will be very simple. So
4:58:39this section is going to do what right?
4:58:40So whatever you have covered in this
4:58:42four files it's going to set your base
4:58:45for the part three because what will be
4:58:48the part three right again part three
4:58:50I'm going to only upload if I get good
4:58:52response from part one and two or else
4:58:54there is no point okay so I just wanted
4:58:55to make this point very very very clear
4:58:58so part three will be only NodeJS pure
4:59:00concept we are going to cover so there
4:59:01will not be any APIs and everything okay
4:59:03so only NodeJS internal code modules
4:59:06worker threads cluster module uh then
4:59:09you have your child processes and all
4:59:10these things. Okay. So this is the
4:59:11reason we are covering very important uh
4:59:13section so that you you will be aware of
4:59:15the time. Okay. We have something called
4:59:17V8 engine. We have something called
4:59:18leave. What is blocking non-blocking?
4:59:20For example, in the part three uh the
4:59:23event loop section only only will take 1
4:59:25hour. Okay. So this is very huge. So
4:59:27that is the reason we are doing this
4:59:29particular section. So first you need to
4:59:31know what actually blocking means and
4:59:32what is non-blocking. First of all, you
4:59:34need to know blocking means the main
4:59:36JavaScript thread that you have, it
4:59:39can't continue with other JavaScript
4:59:41task until unless your current operation
4:59:43that whatever you're doing that
4:59:45finishes. So that means it needs to wait
4:59:47until unless until the current work
4:59:49finishes work finishes. So that will be
4:59:52your blocking, right? So it's actually
4:59:53block your main thread. Okay. On the
4:59:56other side, what will be your
4:59:57non-blocking? Non-blocking means
4:59:59JavaScript can start operation and then
5:00:02it's going to retain or it's going to
5:00:04regain the control before the final
5:00:06result is available. Okay. So now let's
5:00:09see some of the synchronous operation. I
5:00:10think this part we've already covered in
5:00:12the core module. So synchron synchronous
5:00:15operation will be these operation must
5:00:16finish before JavaScript continue. So
5:00:18you have something called remember we
5:00:20have read file sync right? This is we
5:00:23have done. So in that case what will
5:00:24happen right? So JavaScript let's say
5:00:26consider this only JavaScript is going
5:00:28to start the operations your main thread
5:00:30is going to wait this particular
5:00:32operation finishes it's going to return
5:00:34the result and then JavaScript is going
5:00:36to continue with the other task. So now
5:00:38let's say if I go here right so you have
5:00:39a blocking it's going to start the
5:00:41operation your main thread is going to
5:00:43wait until unless let's say this read
5:00:45file sync this particular uh logic
5:00:47whatever you've written this code will
5:00:49execute once this is done then it's
5:00:51going to complete that that particular
5:00:53operation and then JavaScript is going
5:00:54to continue with the other task and this
5:00:56is where it's going to block this
5:00:58operation until unless your current uh
5:01:00task is completed right on the other
5:01:03side we have a synchronous API
5:01:06asynchronous API so we have read file.
5:01:07Now this is this is async operation. So
5:01:10in this case what will happen right? So
5:01:11very very simple way your work is
5:01:14delegated right? So that means
5:01:16JavaScript can continue with other task
5:01:18right once it will complete the other
5:01:20task. Let's say you have a call back and
5:01:22that call back becomes ready and then
5:01:24call back is going to run on the main
5:01:25thread. So it's something like this. So
5:01:27you have your start operation and this
5:01:29is the delegate work means this is
5:01:31non-blocking means your non main thread
5:01:34is continue doing other task at the same
5:01:36time and then it's going to once let's
5:01:38say you're using some callback right
5:01:39your callback becomes ready. So in that
5:01:41case this particular operations
5:01:43completed and then your callbacks
5:01:45becomes ready and then it's going to run
5:01:46the call back on the main thread. So
5:01:48that mean it's not going to block your
5:01:50main thread. So this will be the very
5:01:51basic definition of non-blocking and the
5:01:54blocking. Okay, these can be interview
5:01:56questions also. Why? Because they can
5:01:58give you okay, you have learned file
5:02:00system. Give me some proper example or
5:02:03proper method to differentiate between
5:02:06blocking and non-blocking operation.
5:02:08Okay, so this is the reason I wanted to
5:02:09me uh mention this one. [snorts] So I
5:02:12think this will be simpler one and I
5:02:14think with this we have covered almost
5:02:16four things I wanted to cover in this
5:02:18particular. Let's do one thing in the
5:02:20next section. I'm going to give a very
5:02:21basic overview of the cluster module so
5:02:24that you'll be aware what actually that
5:02:25module is and try to cover that part
5:02:28also and then uh we will start with our
5:02:32crowd implementation which will be
5:02:33postgress section. So let's move on to
5:02:35the next one. Okay. So let's create the
5:02:37last file and this I'll give you some
5:02:39very basic idea of cluster module that
5:02:41what actually this module is. Okay. All
5:02:43right. So let's uh start understanding
5:02:45first that why actually you need this
5:02:47cluster module. So first you know that
5:02:49normal NodeJS process right so you have
5:02:51normal NodeJS process and this will
5:02:53always have one main JavaScript thread
5:02:55correct so it will have one main JS
5:02:58thread so this is the first thing this
5:03:01particular process right so this normal
5:03:02NodeJS process that you have it can
5:03:04handle multiple or many concurrent IO
5:03:07operation but at the end this is going
5:03:09to execute on one main thread only right
5:03:12so now let's say you're running this
5:03:14NodeJS code on your machine and that
5:03:15machine has multiple CPU nodes. So in
5:03:18that case one node just process cannot
5:03:20fully use all of them. Correct? So in
5:03:22that case you have something called
5:03:23cluster module. So what this cluster
5:03:26module is going to do this is actually
5:03:28going to solve this particular problem
5:03:30by starting multiple NodeJS worker
5:03:33processes. So by starting multiple
5:03:37NodeJS worker processes. So what do we
5:03:40mean by this? So first of all you need
5:03:42to know each and every worker process
5:03:44that we are going to have is going to
5:03:46have its own its own NodeJS runtime is
5:03:51going to have its own V8 engine.
5:03:55It's going to have its own event loop
5:03:59and also very very interesting and very
5:04:01important it's also going to have its
5:04:03own main JS thread right and also its
5:04:06own memory. So all these things each and
5:04:09every worker process is going to have.
5:04:11So what this is going to allow this is
5:04:13going to allow several NodeJS processes
5:04:15to run in parallel you're getting
5:04:16because we have multiple worker process
5:04:18right. So uh this is how it's going to
5:04:20work. But how actually this is
5:04:21happening. So let's see. So you have
5:04:23your incoming request. The very key
5:04:25point you need to know this cluster
5:04:27architecture whatever you seeing this
5:04:29will have at least one primary process.
5:04:32So it has to be there and then it's
5:04:33going to have your multiple worker
5:04:35processes. So you have worker process
5:04:37one, process two, process three and
5:04:38process four. Okay. Now what this
5:04:41primary process is going to do? This
5:04:43primary process is going to manage all
5:04:45these worker processes. Okay. So this is
5:04:48going to manage all these worker
5:04:49processes. And what will be the
5:04:51responsibility of this primary process?
5:04:52So first it's going to start all the
5:04:54worker processes. It is going to watch
5:04:56if all the worker processes are in the
5:04:58correct health or not. Health means if
5:05:00let's say something is down or it's
5:05:02something is failing. So it's going to
5:05:03check. It also going to restart the
5:05:05failed worker. So for example, let's say
5:05:07worker two is not working. It is in
5:05:09failed state. So in that case, it's
5:05:11going to restart this worker uh this
5:05:13particular worker process. Okay. Also,
5:05:15it's going to coordinate the process
5:05:17life cycle. So this is how it's going to
5:05:19work. So that means you have your
5:05:21primary process and it's going to have
5:05:22your worker process one, process two,
5:05:24process three and process four like
5:05:26this. Now these workers that whatever
5:05:29you're seeing, right? So we have our
5:05:30four workers. each and every worker can
5:05:34share the same server port. So what I
5:05:36mean by this? So let's say I have port
5:05:3830,00 right? So in this port 30,000 I
5:05:41can run this worker one, worker two,
5:05:43worker three and worker four. Okay,
5:05:45you're getting and then we have another
5:05:48uh concept called request distribution.
5:05:51Now what I mean by request distribution
5:05:53that means whatever incoming request
5:05:54that you are getting that will be
5:05:56distributed among these four workers. So
5:05:59that means let's say you have a four
5:06:00request coming request A, request B,
5:06:02request C, request D. So request A will
5:06:04be handled by worker process one.
5:06:06Request B will be handled by worker
5:06:08process two, three and four and so on.
5:06:10Right? Now here you need to know one
5:06:11thing because each and every workers are
5:06:13separate process. Right? In that case
5:06:15what let's say you have two requests
5:06:17request and request B. These request and
5:06:19request B can execute JavaScript at the
5:06:22same time on different CPU codes. And
5:06:24this is the advantage of using this
5:06:26cluster module. Okay. So I hope this is
5:06:28clear. Now this will be enough. I wanted
5:06:30to give you just very basic idea. These
5:06:32are very vast concept right? So if you
5:06:34go to NodeJS official documentation and
5:06:36just search for cluster module child
5:06:38processes worker threads you're going to
5:06:40get huge huge so many things. So that is
5:06:43the reason I just wanted to cover these
5:06:45five very very important concept. NodeJS
5:06:47internal V8 engine leave blocking
5:06:49non-blocking and cluster model. With
5:06:51this now let's move to the next one. So
5:06:53next on next part will be uh so we are
5:06:56going to cover posgress. So now this is
5:06:58actually mandatory section. So next
5:07:00section you need to do before we are
5:07:02going to start cred. Okay. So with this
5:07:04now let's move on to the next one. Hey
5:07:06everyone welcome back. So in this
5:07:07particular video you are going to learn
5:07:09each and everything that you need to
5:07:10know to start your journey with
5:07:11posgress. Now before I'm going to
5:07:13discuss the curriculum one humble
5:07:15request that please like this video
5:07:17comment and also please share and if
5:07:19possible if you can hype this video it
5:07:20will be very helpful. See I've given a
5:07:22lot of effort to create these kind of
5:07:24free videos for all of you so that you
5:07:26don't have to buy a paid courses. Okay.
5:07:28So this video is a prerequisite of my
5:07:31upcoming NodeJS masterclass video. So I
5:07:33just wanted to mention in case if you're
5:07:35not aware. So I will be uploading a 20
5:07:38hours free NodeJS course on next month.
5:07:41So in that particular course we are
5:07:42going to cover Postgress. So if you
5:07:44complete this particular video it will
5:07:46be very very helpful. So this video will
5:07:48be divided into three sections. So we're
5:07:50going to start with foundations where we
5:07:52we are going to cover the concept of how
5:07:53you can create your database schemas,
5:07:55tables, data types, constant and the
5:07:58concept of primary keys. Then we'll move
5:08:00to the second section which will be very
5:08:02very helpful. So we're going to
5:08:03understand queries and data operations
5:08:05like how you're going to insert rows,
5:08:08select specific columns, basic
5:08:10filtering, the concept of like, I like
5:08:13patterns, null, not null, order by,
5:08:16limit, offset and paginance. how we are
5:08:18going to update single row, how you can
5:08:20update multiple rows and at the end we
5:08:22are going to finish with returning after
5:08:24insert concept and then we're going to
5:08:26move to the last section which will be
5:08:28relationship and advanced SQL. So you're
5:08:30going to understand the concept of
5:08:32foreign keys one to many relationship
5:08:34inner join left join many to many
5:08:36relationship table allises aggregate
5:08:38functions group by count distinct sub
5:08:42queries indexes and at the end we are
5:08:44going to finish finish this particular
5:08:45video with transactions I'm pretty much
5:08:48sure that uh if you complete this video
5:08:50you don't have to buy any paid courses
5:08:52if you're a beginner this will be a
5:08:54perfect start I've added the source code
5:08:56that is completely free in the
5:08:57description you can download from my
5:08:59website. So with that now let's get
5:09:01started and good luck. All right
5:09:03everyone. So now we'll get started. So
5:09:05first of all I wanted to mention I think
5:09:06I already mentioned this one in the
5:09:08intro that this is a practical course.
5:09:10So what I mean by this now if you have
5:09:11already followed my TypeScript course
5:09:13that I've uploaded maybe 2 3 months
5:09:15back. So there what I've done right? So
5:09:18I will uh create individual file for
5:09:22individual concepts and then by writing
5:09:24the commands and the ASQL queries you
5:09:27are going to learn all those concepts.
5:09:28Okay. Now this is actually very very
5:09:30important because I just wanted to make
5:09:32these things very very clear that this
5:09:33is not only a conceptual course. Okay.
5:09:36For example, let's say I'm just going to
5:09:37spend time on what is poss 10 minutes.
5:09:40It's not going to work like that. Okay.
5:09:43So this is a completely practical course
5:09:45for every uh concepts and commands we
5:09:48are going to create individual file and
5:09:49then we are going to run those file and
5:09:51we'll understand each and everything.
5:09:53Now second thing I wanted to mention
5:09:55because I'm using Mac here. So I'm going
5:09:57to download this one for Mac. In case
5:09:59you're using Windows, maybe most of you
5:10:01are going to use Windows. What you can
5:10:03do right, you can use uh sorry, watch
5:10:05these two videos. Both the videos are
5:10:07very good. Maybe you can watch the
5:10:09second one, right? Second one is the uh
5:10:112025 update. So follow this exact one.
5:10:14Uh this is going to show you that each
5:10:17and everything that you need to install
5:10:19and set up posgress. So for this one, we
5:10:21are going to use PG admin. Right? So
5:10:23here first of all what you're going to
5:10:24do right uh you come to this particular
5:10:27uh URL from here right and then whatever
5:10:31you're using based on that you can just
5:10:33download it. So I'm just going to click
5:10:34here
5:10:36and then it's going to download. So
5:10:39let's wait for some time. Okay let's
5:10:42open this.
5:10:45Let's click here open.
5:10:49And here I have to give my password.
5:10:54Okay, click on next. So this is where
5:10:57it's going to install. Next. So we are
5:11:00going to install all of these. So we
5:11:01have Postgress, SQL server, PG admin 4,
5:11:04stack builder and the command line
5:11:05tools. Okay. So I'll do next. Next. And
5:11:09this is actually very very important.
5:11:11Why? This is where you need to set your
5:11:14password. Now try to give the password
5:11:16that you will be able to uh like
5:11:18recollect. So for this one I'm going to
5:11:20use admin. Okay. So I'm going to do
5:11:22admin. And here also I'm going to type
5:11:25admin.
5:11:26Next. This is the port uh that posgress
5:11:29is going to listen. So just keep it like
5:11:32this. Go to next. Uh this is also I'm
5:11:34going to click uh next. And this will be
5:11:36all your settings that we are going to
5:11:38use for our installation. Do next. And
5:11:41now it's going to install. Okay.
5:11:45All right. So, I think this is done. So,
5:11:47I'm just going to uncheck this one and
5:11:48I'm going to do finish. Okay. And this
5:11:51is completed. But now what you're going
5:11:52to do, right? So, I'm just going to
5:11:53close this. And let's see if I just
5:11:55search here PG admin. Okay. And you'll
5:11:58see that you're not going to get it so
5:12:00directly. Why? Because first of all, you
5:12:02have to go to your application in case
5:12:04you're using uh Mac. And then here you
5:12:08are going to get uh Postgress SQL 18. So
5:12:11click here and then from here you'll be
5:12:13able to open this. So just open this PG
5:12:16admin 4.
5:12:18All right. So now first of all we need
5:12:19to give the password. Okay. So I'm just
5:12:21going to give my password here.
5:12:25Okay. I'll do always allow. And now what
5:12:28we're going to do right. So you can see
5:12:29that we have the servers. So here first
5:12:32of all we need to connect. So here and
5:12:35this is where you have to give your
5:12:36password that you have given. So in my
5:12:38case I've given what admin. So I'm just
5:12:40going to give this one admin and then
5:12:42I'm do save password and I'll do okay.
5:12:46And now you see that this will be now
5:12:47connected. Okay. And you can just open
5:12:49this. And this is where you are going to
5:12:53see all the things visually. Okay. But
5:12:57this is what I will suggest not to focus
5:13:00too much at the beginning. Why? The
5:13:03reason is when you have something that
5:13:05you can learn visually, you will be able
5:13:07to understand once you know the uh
5:13:10concepts and the basics very very
5:13:12clearly. So what I mean by this? So here
5:13:14you'll see that if I go to now
5:13:16databases, you'll be see you are going
5:13:18to see I think this is little slow.
5:13:20You'll see that we have one uh default
5:13:22database here. Now what you can do right
5:13:24you'll be able to create database from
5:13:26here. Let's say if I do right click this
5:13:29is very slow. Okay. So you can do create
5:13:31database and all those things. What we
5:13:33are going to do right each and
5:13:35everything that how we are going to
5:13:37create a table, how we are going to
5:13:39insert data, how we are going to read
5:13:41our data, how we are going to update our
5:13:43data, all those things via command line.
5:13:46So for this one we have something called
5:13:48psql. Okay. So why I'm actually focusing
5:13:51too much on this particular part because
5:13:53here if I just focus too much on
5:13:55learning all those things definitely we
5:13:57can also do that. But why I'm suggesting
5:14:00you if you're a complete beginner that
5:14:02try to master command line things a much
5:14:05better way. So what I'm telling let's
5:14:07say you are working in a particular
5:14:09project where they are using posgress
5:14:11and someone ask you okay give me this
5:14:13particular data. So now you don't want
5:14:15to go to your DB so you can go to your
5:14:17DB and then you can go to your tables
5:14:19you can go to rows and you can see the
5:14:20data that is fine. But if you are a
5:14:22master in Postgress SQL, what you can
5:14:24do? You can just simply run a particular
5:14:26query and you'll be able to get all the
5:14:27data. You're getting you're getting what
5:14:29I mean. So this is where you have to
5:14:31focus. So these things we are going to
5:14:33discuss later. For now, you have to make
5:14:35your posgress foundation very very
5:14:38strong. And this is exactly how I have
5:14:40learned the same thing that how how I'm
5:14:42teaching here. You believe me or not?
5:14:44Okay. So what we are going to do right
5:14:46first of all what we need to do right, I
5:14:48already created one blank folder here.
5:14:50You can see that I don't have anything
5:14:51else. Now we are going to follow a
5:14:54certain process and the folder structure
5:14:56so that sequentially you can learn all
5:14:58those concepts line by line. So what I
5:15:01mean by this? So first of all what
5:15:02you're going to do right I'm going to
5:15:04create two folder here. So I will
5:15:06suggest that you also follow the exact
5:15:08same process. So one will be part one
5:15:10because I've given lot of uh time uh
5:15:12deciding all those things right. So
5:15:14don't think this is like very random
5:15:15that I'm creating. I I will give lot of
5:15:17time creating all those curriculum in
5:15:19what sequence we are going to learn so
5:15:21that it will be easy for you to
5:15:22understand. So here I'm going to give
5:15:24part one and then there will be part
5:15:26two. Okay. So part one we are going to
5:15:29learn very very basic things. For
5:15:30example, how you can create database,
5:15:32how you're going to create schema, how
5:15:34you can create your table, what are the
5:15:36data types, what are the constants,
5:15:38primary keys, all those things. In part
5:15:40two we are going to go into little bit
5:15:42advanced level. Okay. So you're going to
5:15:44learn all the SQL uh concepts for
5:15:47example how you can insert a single row
5:15:49how you're going to insert multiple rows
5:15:51okay you are getting right and then we
5:15:53are going to have part three but that we
5:15:54are going to do later. So now inside
5:15:56this part one what we are going to do we
5:15:59will be creating each and every SQL file
5:16:01with a sequence. So what I mean by this
5:16:03I'm just going to do 01 and then I'm
5:16:05going to do first database or DB or
5:16:08something. So that mean this will be
5:16:09your initial thing that you need to
5:16:11understand. I hope this is clear. So
5:16:13this will be our folder structure that
5:16:14we are going to follow. Now before doing
5:16:16that so let's understand very very basic
5:16:18things like although I mentioned that we
5:16:20are going to not going to cover some of
5:16:21the concept but what actually posgress
5:16:23is. So posgress is a database system
5:16:25right now why uh so now if you're a
5:16:29complete beginner what actually a
5:16:30database system now see when we have
5:16:32some real application we need to store
5:16:34our user information let's say our
5:16:36product information or the app that you
5:16:38are creating based on that posgress is
5:16:40going to we are going to use to store
5:16:43this kind of application data in a
5:16:45structured way okay so in a structured
5:16:47way why this is very popular and it's
5:16:50extremely popular and the reason is
5:16:52because it's it's actually give the
5:16:54developers right that we are developers
5:16:56we are going to develop so many
5:16:58advantages that other DVs actually lacks
5:17:01for example first of all will be
5:17:03reliability okay now first of all when
5:17:06you're creating a products and
5:17:08application you can't lose your data
5:17:10very very easily right and that will be
5:17:12a disaster for your application for
5:17:15example let's say I'll give a practical
5:17:17example that if your user you have a B2C
5:17:20application and your user is placing an
5:17:23pays real money okay and let's say or
5:17:26maybe updating their profile so what we
5:17:28need to do your DB should be responsible
5:17:31for updating all those data properly and
5:17:34posgress SQL is trusted for this kind of
5:17:37data handling like it's extremely
5:17:40popular second it's give you the SQL
5:17:42support right so possql is usually use
5:17:45SQL what uh SQL means structured query
5:17:48language right you can also search all
5:17:50of these in Google also right So what
5:17:52actually structured query language is?
5:17:54So this is the language that we talk to
5:17:56relational databases. Okay. So that we
5:17:59are going to discuss later that what are
5:18:01the commands and everything we have and
5:18:03one very very popular advantages of
5:18:06posgress SQL will be and that is the
5:18:08relationship between your data right so
5:18:11what will happen right whenever you have
5:18:12a backend application your data the real
5:18:15data will be connected for example one
5:18:18user can create multiple post one order
5:18:21belongs to one customer so one order
5:18:23cannot belong to multiple customer these
5:18:26things are very basic concepts right so
5:18:28this is where post SQL is extremely
5:18:31strong I repeat extremely strong at
5:18:34storing and querying all those relations
5:18:37data okay so these things will be the
5:18:40advantages some of the very advanced
5:18:41features that uh your posgress is going
5:18:44to give you that we are going to not
5:18:46going to cover that much here let's say
5:18:48we have indexes for f queries we have
5:18:50transactions we have full text search
5:18:52lot of things views triggers stored
5:18:55function extension if I'm getting good
5:18:57response from this particular video I'm
5:18:59going to create one more part two. Okay.
5:19:01[snorts] So this will be your postgra
5:19:04square with the very definition. Right?
5:19:05Now one thing you need to understand and
5:19:07that is one of the most important
5:19:08concept that you can get. You can also
5:19:10note it down that what is the relation
5:19:13sorry what is the non-re what is the
5:19:15differences between a relational and
5:19:17nonreational DB. Okay. Now if you're a
5:19:21student you have maybe heard this
5:19:23particular term that SQL database NoSQL
5:19:26database relational database non
5:19:28relational database something like that
5:19:29right so what is the actual definition
5:19:31of a relational database so relational
5:19:33databases actually stores data in a
5:19:36table format okay so I'm just going to
5:19:39let's do one readme
5:19:42so here I'm just going to do that
5:19:44relational database
5:19:47relational db is going to store the data
5:19:49in what? In tables format or in tables,
5:19:52right? And these tables these tables can
5:19:55be connected using relationships.
5:20:00Okay,
5:20:02let's say you have a users table,
5:20:05you have a post table, you have a
5:20:07comments table or whatever blah blah.
5:20:11Okay.
5:20:14So here what situation can happen that a
5:20:16particular post is belong to one user.
5:20:19So one post belong belongs to one user
5:20:24something like this. Okay.
5:20:27And let's say one comment
5:20:30belong to one particular post something
5:20:34like this. And this connection that we
5:20:36have this is called relationship. Okay.
5:20:39So now uh this is one more thing we can
5:20:42mention that one user okay this is also
5:20:44important that one user
5:20:47can have many post
5:20:50right so this is called one to many
5:20:52relationship that we are going to
5:20:53discuss later so this will be relational
5:20:55DB non- relational DB will be it
5:20:58actually doesn't organize the data using
5:21:00connected tables right right so we'll do
5:21:02non relational
5:21:05uh non relations DB
5:21:09So it's normally doesn't
5:21:13uh organize
5:21:17data using connected tables.
5:21:22Okay. Now here what actually these kind
5:21:25of DVs use? They use documents. So we
5:21:27have what MongoDB, right? Or it also
5:21:30uses key value pairs. Key value
5:21:34pairs. So this will be the very basic
5:21:37definition between a relational and non
5:21:41relational DB. Okay. Now this is another
5:21:45very important interview questions that
5:21:46when you're going to use relational DB
5:21:48or when relational DBs are a good
5:21:51choice. So you have to mention that we
5:21:53we are going to use postgress SQL when
5:21:55we have our data that has clear
5:21:58structure that has proper relationship.
5:22:01Right? You also need to implement
5:22:03transactions. you need joins right also
5:22:07you also need strong validation at the
5:22:09database level okay so these things each
5:22:12and everything that I'm mentioning very
5:22:14very important so first of all will be
5:22:15data has clear structure so I'm just
5:22:17going to write in short second will be
5:22:19data has relationships
5:22:22relationships
5:22:24then maybe let's say you need to
5:22:26implement transactions
5:22:29also you need joins and as I already
5:22:32mentioned that you also need strong
5:22:33valid validation strong validation at DV
5:22:37level. Now example will be let's say
5:22:39you're creating a banking application
5:22:44all right and or maybe let's say you're
5:22:46creating a e-commerce something like
5:22:48this or let's say you're creating a CRM
5:22:50application so here you can use
5:22:53relational non-reational you're going to
5:22:56use when your data save or data is going
5:22:59to change very often right so
5:23:02non-reational will be when your data
5:23:04changes
5:23:06very often. Okay. Documents that you
5:23:10have, I already mentioned that
5:23:11non-relations DB is going to store your
5:23:13documents in sorry store your data in
5:23:15documents. So when your docs or
5:23:18documents are independent
5:23:20so not that much relations are there
5:23:22okay you don't need much joins
5:23:27right so in this case you have to use or
5:23:30you can use not you have to you can use
5:23:32non-reational DB. Now why am I
5:23:34explaining all of this? Because this is
5:23:36actually very very important. This is so
5:23:38important right? I can't even explain.
5:23:40You go to any company you'll see that
5:23:41whenever they're going to start a new
5:23:43product there will be a lot of
5:23:45discussions with the product business or
5:23:47leadership whatever that they what DV
5:23:50they're going to use it's extremely
5:23:52important why because once you start the
5:23:56product let's say you started one
5:23:57particular DB and that is a wrong choice
5:23:59it can be huge problem because then
5:24:01again you need to migrate and there can
5:24:03be lot of things right developer cost
5:24:06timing and all those things are matter
5:24:07so that is the reason these things are
5:24:09very important Now if I want to sum up
5:24:11that when you are going to implement any
5:24:13kind of project right you have to first
5:24:15see the requirement but in overall
5:24:17posgress SQL is a very very strong very
5:24:20strong DB choice okay so this is what I
5:24:22wanted to mention so very basic concepts
5:24:25so with this now from the next part what
5:24:27we're going to mention as I already
5:24:30told that for every concepts we are
5:24:32going to create one one file and then we
5:24:33are going to see in the terminal the
5:24:35same thing I'm also going to show you in
5:24:36the PG admin but we'll focus more on the
5:24:38SQL queries that will be your main
5:24:40object. So let's move on to the next
5:24:42one. All right. So now we'll start our
5:24:44journey of learning Postgress SQL
5:24:47concept wise but practically. Before
5:24:50that as I already mentioned this
5:24:51particular term in case you are not
5:24:53aware and that is psql which is the
5:24:55official terminal based command line
5:24:57interface for postal SQL right. So what
5:25:00we are going to uh why we need this or
5:25:03when we are going to use this when we
5:25:05need to
5:25:07run our SQL queries. You can see that it
5:25:09allows uh to interactively type SSQL
5:25:12queries, issue them to the database
5:25:15server and you can also view the result
5:25:17directly in your terminal and this is
5:25:19the thing I was talking about that
5:25:20definitely whenever you are going to
5:25:22work with your DB you can definitely see
5:25:24the result in your DV right but when you
5:25:27can run any kind of commands and then
5:25:29you'll be able to get the result in the
5:25:31command line. So that means what you
5:25:32know your concepts very very well and
5:25:35that is very important thing that we are
5:25:37going to at least learn in this
5:25:39particular video. So first of all let's
5:25:41start with I think we have done enough
5:25:44talking. So let's start with first file
5:25:46which will be 01 first databaseql.
5:25:52Okay. So this will be a first file. So
5:25:54first what we are going to do it. So
5:25:56first we're going to understand that how
5:25:58you can create your first DV. Now here
5:26:02what I'm going to do right. So first I'm
5:26:04just going to write here that okay
5:26:06create and then I'm just going to do
5:26:08here database and let's give this a name
5:26:11as Postgress
5:26:13SQL. Okay. So we have post no let's do
5:26:16postgra SQL
5:26:19part one. So this is my DB name. So what
5:26:23actually this command is doing here
5:26:25right? So this thing is doing. So this
5:26:27create a database is going to create a
5:26:29new DB. So this is going to create.
5:26:34So this is going to create new DB right
5:26:38where inside your postgrade I'm going to
5:26:42write insert postgrade server.
5:26:45So this is how you can create your first
5:26:47DB. So now one thing you need to
5:26:50understand that in postg server you can
5:26:53have multiple databases right. For the
5:26:55part one, what are we going to do? We're
5:26:57going to use one single database so that
5:26:59we can understand and all the things
5:27:00will be in sync. Now when we going to
5:27:04run this particular file, what will
5:27:06happen? So this file once it will run
5:27:09successfully, it is going to connect to
5:27:10your new DB, right? And then what we can
5:27:14do from our psql command line, we can
5:27:16actually connect directly to this
5:27:19particular DB. But before that I'm just
5:27:21going to give you one more uh command
5:27:23here that you need to know. But remember
5:27:25I'm going to write it explicitly that
5:27:27this is actually not needed and you
5:27:28should never do it in your real products
5:27:30and application and that is first I'm
5:27:32going to do the drop database
5:27:35if exists
5:27:37and then I'm just going to give this
5:27:39name posgressql part one. So what
5:27:41actually we are doing here? So you're
5:27:43simply telling that you are going to
5:27:46drop this particular DB if it is already
5:27:48present. drop database is going to
5:27:50remove this database completely and I'm
5:27:53just going to write it here that you
5:27:54should you should never
5:27:58do it in prod app and this is so I'm
5:28:04just going to write it here so this is
5:28:07only for
5:28:10learning okay so two things we have
5:28:12learned one is how you can drop a
5:28:14database and how you can create a new
5:28:16database okay so now let's see how we
5:28:18are going to connect to this particular
5:28:20and how we are going to run this
5:28:22particular file that is also important
5:28:23as I already mentioned that we are going
5:28:25to use command line and for this one you
5:28:27can use a individual command line but
5:28:29I'm going to use VS code only because it
5:28:31will be easy for us to understand
5:28:33so first of all I'm going to run this
5:28:35particular command okay and I'm going to
5:28:37explain that what each and everything is
5:28:38doing here this is each and everything
5:28:40see we are going to do from this
5:28:42particular point you need to understand
5:28:44everything you can't memorize these
5:28:46things in case you're not able to do it
5:28:48will be very difficult for you to
5:28:50understand when you will actually build
5:28:52your backend applications. So here I'm
5:28:55just going to do psql u and I'm just
5:28:58going to do this one as posgress
5:29:00space - d and I'm just going to do
5:29:03posgress and here I'm just going to do
5:29:05hyphen f and then I will go to my part
5:29:08one which is this particular folder part
5:29:10one slash and then I'm just going to
5:29:12give this file name. So I'm just going
5:29:14to copy this here and then I'm just
5:29:16going to paste it. So what actually this
5:29:18is doing here? So first our psql is our
5:29:21posgressql command line tool hyphen u
5:29:24pososegr is nothing but we are simply
5:29:26telling that we are logging as our user
5:29:28which is posgress hyphen d posgress
5:29:31means we are going to connect to our
5:29:33database posgress and hyphen af this
5:29:36particular means we are going to run
5:29:38this commands from this particular file
5:29:40as simple as that okay so in sum up you
5:29:43it's telling that use psql login as
5:29:46posgressql user connect to your posgress
5:29:49database and run run this particular SQL
5:29:51file. That's it. And we going to do
5:29:53enter. You have to give a password and
5:29:55I'm just going to give admin enter.
5:29:59And you can see that what it's saying.
5:30:01So this is fine. So this doesn't exist.
5:30:04So it's going to skip which is fine.
5:30:05Drop database and create database. So
5:30:07that means this is actually created. So
5:30:09now if I just go here, right? And let me
5:30:11just I don't know why this is very slow.
5:30:14So let me refresh this.
5:30:17I think I get this particular thing in
5:30:20other places also that this is uh little
5:30:23slow this issue also reported by other
5:30:25users also and you can see that we have
5:30:27this postgrad SQL part one and I'm just
5:30:30going to do right click not right click
5:30:32I think let's open this and you're going
5:30:35to see all the details and everything
5:30:36schemas and everything but for now let's
5:30:39leave it here so that means now you have
5:30:41your DB here so what I will suggest let
5:30:44me just move this one here So what I'm
5:30:47actually suggesting that try to
5:30:49understand each and every command very
5:30:51very seriously because this is what you
5:30:54need to work in your company also when
5:30:56you'll be working as a backend developer
5:30:58you have to work with your DB you need
5:31:00to know each and everything like like
5:31:02such a way so that if someone ask you
5:31:04okay give me this particular command SQL
5:31:06query or everything you should be able
5:31:08to do it like this right so first of all
5:31:11we learn that how you can create a new
5:31:13DB and how we are going to run this okay
5:31:15Now I'm going to show you that how you
5:31:17can run your psql queries from your
5:31:20terminal. So first I'm just going to
5:31:22clear this. So first let's do here psql
5:31:25- u. So which will be our user which is
5:31:27posgress and I'll do hyphen d and this
5:31:31is our db and then I'm just going to do
5:31:34enter and you'll see that it's asking
5:31:35for this password every time. Okay. So
5:31:37you have to give the password every
5:31:38time. So what we going to do right? So
5:31:40let's cancel this and I'm just going to
5:31:44add this password here.
5:31:48Okay. So now let's clear once again and
5:31:50then we are going to just run once again
5:31:54here and you can see that now this is
5:31:56connected. So now I'm going to show you
5:31:58that some of the things that you can
5:31:59directly check from here. So first of
5:32:02all let's say you want to see which
5:32:05current database that you are using. So
5:32:07here what you can do right you're going
5:32:08to do select and you're going to do
5:32:10current underscore and you have to do
5:32:12database.
5:32:15All right and then you'll do enter and
5:32:17you can see that this is our current
5:32:18database. And now remember this is we
5:32:21are actually writing inside your psql
5:32:23command line. Okay. Now you want to see
5:32:26the current user. So you're going to do
5:32:28select and you'll do current user.
5:32:31Enter. This is the current user which is
5:32:33posgress. Okay. Now you can also see
5:32:37which version of Postgress SQL you're
5:32:39using. So I'm just going to do select
5:32:41and here if I'm not wrong it will be
5:32:44version and this will be the this is
5:32:46going to give you the version. Okay you
5:32:48can see that this is the version that we
5:32:49are using right. So now let's say you
5:32:52want to see all your databases that how
5:32:55many databases I have. So you have to
5:32:56give slash I don't know which what but
5:32:59this particular uh icon called u. So I
5:33:03think this is called back slash I think
5:33:05and then this will be l and here you're
5:33:08going to get all these okay all the
5:33:11databases. Now let's say you want to see
5:33:13all your tables. So for tables you have
5:33:15to do dt and here you can see that we
5:33:17don't have any tables for now which
5:33:19makes sense. Now you want to exit your
5:33:21psql command line. So you can also type
5:33:24here exit directly. So let's see if I do
5:33:26exit it will be it will be uh it will
5:33:29exit. Or else you can also do like this.
5:33:32You can directly do uh slash and then
5:33:35you have to do Q. So this is going to
5:33:37also do the exit. Okay. So both the
5:33:39things are very important. So you can
5:33:42use exit or this particular / Q. So this
5:33:45will be the very first thing basic
5:33:46things you have learned. So now let's
5:33:48move on to the next one which will be
5:33:50how we are going to create our schema.
5:33:52So here I'm just going to create one
5:33:54more file and let's do this one as 02
5:33:57and I'm just going to do this one as
5:33:59first schema.sql.
5:34:02Okay, let's bring it here. So first of
5:34:06all, how we are going to create your
5:34:08first schema? What actually schema? Now
5:34:11schema is like a folder inside your
5:34:13database. Okay, now there will be some
5:34:16default schema it's going to create,
5:34:18right? So you see that you have the
5:34:19schema. Let's expand this.
5:34:23See that there is a public schema that
5:34:25will be created and inside this also
5:34:27you're going to have the tables. Okay.
5:34:29So this is your public or default schema
5:34:31that postsql always has. So now let's
5:34:34say we want to create our own schema. So
5:34:37we going to have our DB. So it's like
5:34:39this. So I'm just going to give a
5:34:41comment. Okay. So here I'm just going to
5:34:44have the DB. DB is going to have the
5:34:46schema. Schema is going to have the
5:34:49table. table is going to have the rows
5:34:52something like that. So now I want to
5:34:53create my own schema. So how I can do
5:34:56that and that is very very simple. So
5:34:57I'm just going to do create schema and
5:35:00then I'm just going to do if not exists
5:35:04and then you have to give the name. So
5:35:05I'm just going to do basic something
5:35:06like this. Right? So create schema is
5:35:08going to create a name space for your
5:35:10table and your other database objects.
5:35:13What actually if not exist means? So
5:35:15this is going to prevent an error. Very
5:35:17very important. If this schema is
5:35:20already created, so this is going to
5:35:22this if not exists
5:35:26is going to
5:35:29prevent an error, right? Uh if the
5:35:33schema
5:35:36schema
5:35:39is already
5:35:41created. Okay. So this is how you can
5:35:44create a schema. All right. So this is
5:35:46how you can create a schema. Now here
5:35:48I'm also going to show you that how you
5:35:49can create a extension and why actually
5:35:51you need it. So I'm just going to do
5:35:52here create extension
5:35:55if not exist and here I'm just going to
5:35:59use pg crypto.
5:36:02Okay. So what actually this extension is
5:36:04going to do? So in later part we are
5:36:06going to use uh something called get
5:36:08random UID which will help us to create
5:36:12UID primary keys and that is very
5:36:14important because in Postgress SQL what
5:36:16we can do right we can directly create
5:36:18or generate UID. So here this particular
5:36:21extension is needed because this is
5:36:23going to help us to create that
5:36:25particular UID. Okay for later we are
5:36:28going to discuss uh this particular
5:36:29particular thing in details. So now what
5:36:31I'm going to do right so this is going
5:36:33to create the schema and this is going
5:36:35to create the extension right I think
5:36:37extension spelling is also correct all
5:36:40right now what I'm going to do right now
5:36:42this is where I wanted to explain one
5:36:44more thing which is very important so
5:36:45here what I'm going to do right I'm
5:36:47going to write a query okay so here I'm
5:36:49just going to write a query now this
5:36:51query I can directly write from my psql
5:36:54command line also but now you may ask me
5:36:56that why I'm writing this one here the
5:36:58reason is this is for the teaching
5:37:00purpose this This is not mandatory. This
5:37:03is optional. Why I'm doing this? Because
5:37:05when you are going to download this
5:37:06source code, you will be able to
5:37:07directly see this query or you can copy
5:37:09and you can run. Okay. So that is the
5:37:11reason I'm going to follow this
5:37:13particular uh process throughout this
5:37:16video, not for this particular file. So
5:37:18now let's say what I need to do, right?
5:37:20I want to write a particular query which
5:37:22is going to give me all the schemas that
5:37:24are available in my current DB. Okay. So
5:37:27to do that, what we're going to do,
5:37:28right? We're going to use a select and
5:37:30here I'm just going to use a schema name
5:37:33and then I'm just going to do from and
5:37:35this we have something called
5:37:36information
5:37:38schema
5:37:40schema schemata. So what actually this
5:37:43is doing now this information doss
5:37:44schema dos schemata is a system view.
5:37:47What actually system view? So system
5:37:48view is a built-in view that is going to
5:37:51give you the information about your
5:37:52database structure. For example, let's
5:37:54say you want to see all your database
5:37:56schemas that how many schemas are
5:37:58available. So in that case, we can use
5:38:00this. And here I'm also going to do
5:38:01order Y by for now. Let's skip this. We
5:38:04are going to have a separate section on
5:38:06what actually is order Y. So I'm just
5:38:07going to do order Y of schema name.
5:38:10That's it. So now what I can do right, I
5:38:12can simply directly run this particular
5:38:14file which is going to create a schema
5:38:17going to create this extension and at
5:38:19the end it's going to run this
5:38:20particular query. All right. So now
5:38:22let's run this file and what we can do
5:38:24right. So let me just copy this
5:38:28and then we'll paste it here. So what we
5:38:30are doing so loopsql u posgress d this
5:38:34is the db that we have created in the
5:38:36first uh uh file and part one/ Now we
5:38:40need to run this file. Okay. So I'm just
5:38:42going to copy this and then let's paste
5:38:45it here.
5:38:47Enter. And you can see that now we have
5:38:50the schema is created extension is
5:38:52created and you are getting so many
5:38:54schemas. Okay. Now this might be a
5:38:55little confusing that from where these
5:38:57are coming.
5:38:59First one so basic schema is your custom
5:39:01schema that you have created. What is
5:39:03the information schema? This is the
5:39:05posgress standard metadata schema. Then
5:39:08you have the PG catalog. This is
5:39:09posgress internal system schema. PG
5:39:12toast. Uh if I'm not wrong this is
5:39:15internal storage schema for large
5:39:17values. Right? You can also check it
5:39:19once not exactly see what's so pg toast
5:39:22schema in to place you can just search
5:39:24it.
5:39:30Okay. So you can see that this is
5:39:31internal names we used for the oversiz
5:39:33attribute right so it's for large values
5:39:36and then you have the public which I
5:39:37already mentioned that every posgress is
5:39:39going to have a database is going to
5:39:41have a default schema uh which will be
5:39:43present in every database. Right now why
5:39:46this is coming up because in the query
5:39:49I'm actually getting all my schemas at
5:39:51once. Right? And this information schema
5:39:53dots schemata is going to give me all
5:39:55the schemas that are available in my uh
5:39:57database. All right. So now uh if you go
5:40:01here right so so this is our uh DB. So
5:40:03now let me just refresh this.
5:40:07This is very slow man. In Windows it is
5:40:09first. I don't know. I think that is the
5:40:11reason so many issues I think they have
5:40:13reported on this. I don't know why this
5:40:15is this much slow. Even I'm using the
5:40:17latest version of Mac but still it is
5:40:19very slow. So if I go to schemas and
5:40:22let's see what we getting here. So you
5:40:24can see that we are already getting two
5:40:26schema and you can see that we have the
5:40:27basic schema. Fantastic. So that means
5:40:29this is now completed. So this is how
5:40:31you can create schemas and also
5:40:33extension. Now moving to the next one
5:40:35which will be very very important. So
5:40:37for now what you're going to do right
5:40:38I'm just going to do 03
5:40:41and let's do this one as first table
5:40:44dossql. So now we are going to
5:40:46understand that how you can create
5:40:47table. Okay. So first of all what
5:40:49actually table? So table is going to
5:40:51store your data right or store one type
5:40:55of data. So here let's create a simple
5:40:58students table. So now what we going to
5:41:00do right your table is going to live
5:41:02inside your schema. And now we have
5:41:04created a basic schema here. So what I'm
5:41:06going to do right inside my this
5:41:08particular schema you wanted to create a
5:41:10table. So first of all I'm just going to
5:41:11do drop table. Now again don't do this
5:41:13in your real project. This is just for
5:41:15teaching purpose that this is how you
5:41:17can also drop table. Okay. So this will
5:41:19be drop table and here this will be if
5:41:22exists and I'm just going to do basics
5:41:25dot let's do students. Okay. So inside
5:41:29my basic schema you wanted to have a
5:41:30students table. Simple. And then I'm
5:41:32going to create a table. We'll do create
5:41:34table and I'm just going to do basics
5:41:36dot students and here now we have to
5:41:39have all our property. So let's start
5:41:41with the first one. First I need to have
5:41:42a id which will be serial and this will
5:41:46be my primary key. Now what actually we
5:41:48are doing here. Now this ID is your
5:41:51unique value. Right? So what this serial
5:41:54is going to do this is going to create
5:41:57an auto incremental
5:42:00or auto incrementing
5:42:02integer. Okay. So that means if I'm
5:42:05inserting one particular student with ID
5:42:071 from next time when I'm going to
5:42:09insert it it will be like 2, 3 like this
5:42:12and so on. Right? so on. So your four
5:42:15five something like this right? Primary
5:42:18key very very important very important
5:42:20concept that this simply means so
5:42:22primary key simply means
5:42:26that this
5:42:28column
5:42:29uniquely
5:42:32identifies
5:42:33each row. Okay. So this will be the
5:42:37first property that I wanted to have or
5:42:39column. Then I'm going to have a name
5:42:41property which will be text and I'm just
5:42:43going to make this one as not null. So
5:42:46what we are simply telling that this is
5:42:48my another property. So text is going to
5:42:52represent string data. Then I'm simply
5:42:56telling that not null
5:43:00uh means
5:43:02this column is required. Right? So that
5:43:06means
5:43:07postgress is going to
5:43:10reject if this name value
5:43:15is not present. As simple as that. Then
5:43:19I'm also going to take a email property.
5:43:21So I'm going to take a email which will
5:43:22be text. This also will be not null. And
5:43:25this will be a unique property. Okay?
5:43:27Because every student is going to have
5:43:29their unique email. All right? So unique
5:43:32means
5:43:34unique
5:43:37means that um no two student
5:43:45is going to have
5:43:48uh same email. Okay. Then let's take an
5:43:52one more property and then I'm just
5:43:54going to take a age property. This will
5:43:56be integer. I'm just going to take a
5:43:59check. So check is going to add a rule
5:44:01that every student age has to be greater
5:44:04than or equal 18. So this is one check I
5:44:06wanted to give and at the end I'm going
5:44:08to take a created at property. So do
5:44:11created add which will be timestamp
5:44:17and here I'm just going to do this one
5:44:18as default. Now so what we are doing
5:44:21here so simply telling that this time
5:44:23stamp is going to store your date and
5:44:26time format. So time stamp is going to
5:44:28store your date and time format. Default
5:44:33means if you don't give anything it's
5:44:34going to take by default.
5:44:37Default means if you don't give any
5:44:41value
5:44:44it will take by default.
5:44:49That's it. So now I think this is done.
5:44:52So first of all let's create this table
5:44:54and let's see if this is creating inside
5:44:56that particular schema or not. So first
5:44:59of all let's go here. I'm going to clear
5:45:03this and then I'm just going to run it
5:45:05here. So we are running inside this and
5:45:07then I'm just going to copy this. Let's
5:45:10do rename and then let's run it here.
5:45:16Enter. And you can see that it's created
5:45:19the table. So you can go here and let me
5:45:21just refresh this.
5:45:29So if I go inside this you'll be see
5:45:31that we'll be having the tables and
5:45:33inside this you're going to have your
5:45:34table one table which is my student
5:45:36table and you can see the columns and
5:45:38everything here right. So you can expand
5:45:40this and you can see all your properties
5:45:42that you have added. So ID, integer,
5:45:44name, email, age and created date. Okay.
5:45:47So that mean this is working fine. So
5:45:49now [clears throat] what we going to do
5:45:50right? So we need to insert some values
5:45:53so that we can see that whether we we
5:45:55have those values or not. Correct. But
5:45:57before that let's do one thing. Let's
5:45:59run some of the uh commands here. Okay.
5:46:03Inside psql so that you can understand
5:46:04what is happening here. So first of all
5:46:07inside this. So let's run this command.
5:46:10So I'm just going to open this. So do
5:46:13psql - u postgress and then I'm going to
5:46:17run this db. So inside this and then
5:46:19first of all I wanted to see my tables.
5:46:21I'll do /dt.
5:46:23Okay it's showing no tables.
5:46:27Oh I think we need to do /dt and we need
5:46:29to go to basics basics dot and then
5:46:33we'll do star.
5:46:35Okay. So you can see that we have to do
5:46:37list of tables. Schema basics name
5:46:39students. This is table owner is
5:46:41postgress. Fantastic. Now first of all
5:46:45before we'll do anything right we need
5:46:47to add some data so that you can check
5:46:49whether we have any student present or
5:46:51not. Correct? So how we are going to do
5:46:53that? So see this is what I was talking
5:46:56about that these queries that I'm
5:46:58writing here these direct queries I can
5:47:00directly run here also inside psql. The
5:47:03reason why I will be adding here so that
5:47:04when you're going to download the source
5:47:06code you can take the reference from
5:47:07here. I hope you're getting right. Don't
5:47:09get confused. These queries you don't
5:47:11have to write in the file. This is for
5:47:12the teaching purpose. So for now I'm
5:47:14just going to exit from here. Clear
5:47:16this. And then let's run the first uh
5:47:21query here. So I'm just going to do
5:47:23what? So I'm going to insert some uh
5:47:25data. So insert some data.
5:47:28So to do this one, we're going to do
5:47:30insert
5:47:32and insert we need to do into. So you
5:47:34have basics dot students. So this is the
5:47:38table and what are the things we need to
5:47:39insert. So first of all id will be
5:47:41automatically created then we have name
5:47:44comma we have email comma we have age
5:47:47these three things right. So this is the
5:47:50things we want to insert but we need to
5:47:52tell right okay what values we wanted to
5:47:54insert. So that means we need to give
5:47:56here values and these values is going to
5:47:59tell me that okay these things I wanted
5:48:01to insert. So I'm just going to add sum.
5:48:05So let's give one more email. So do
5:48:07thegmail.com
5:48:10and comma I'm just going to give here 55
5:48:13although I'm not 55 just I'm just
5:48:14giving. So here I'm just going to copy
5:48:16this paste it here. Let's do here John
5:48:20and I'll do this one as John and then
5:48:23let's do 23. Okay. And we need to give
5:48:27this one. So this will be the first uh
5:48:30data that I wanted to insert. So now
5:48:33what I'm going to do right so let's run
5:48:34one second and we'll see that what is
5:48:36happening here. Okay. So first of all
5:48:38I'm going to run this file again and see
5:48:40that we have insert something is
5:48:42happening here but we don't know what
5:48:43actually happened. So first we need to
5:48:45see that whether we have all this data
5:48:48present inside our table or not. So
5:48:50first I'm going to go inside this and
5:48:52then I'm what I'm going to do right. So
5:48:54I'm just going to do select
5:48:57star and I'm just going to do from. So I
5:48:59have to go to basics
5:49:02dot students. So it's simply telling
5:49:05that select is going to read your data
5:49:07from a table. This star means we need
5:49:10all the columns. Okay. So this is what
5:49:12you need to enter. And you can see that
5:49:14we have two data. ID one sum email this
5:49:18created at John and this is the data.
5:49:20Fantastic. Now this is what I was
5:49:22talking about. The same query I can
5:49:24write inside this file also so that
5:49:27whenever you're going to run this file
5:49:28you'll be able to get the result
5:49:30immediately. Okay. So let's see if I
5:49:33just wanted to write it here. So
5:49:34something like select
5:49:37from and then you're going to do basics
5:49:39dot students it's going to do the exact
5:49:41same thing. Okay. So now I think this is
5:49:43done. So this is how what you're going
5:49:46to do. You're going to create your
5:49:47table. You can drop table using drop
5:49:49table command. So [snorts] create table
5:49:51you have to take all your properties
5:49:53that you're going to take and based on
5:49:54that if you want to insert some data you
5:49:56need to insert and then if you want to
5:49:59uh read the data you need to select and
5:50:01then you have to tell that okay from
5:50:03which place I wanted to read the data.
5:50:05So in our case this will be our basic
5:50:07schema dot students table. So with this
5:50:10now let's move on to the next one. All
5:50:12right. So now let's move on to the next
5:50:14one which will be going to understand
5:50:15some of the data types. Okay. So I'm
5:50:17just going to do 04 data types dots sql.
5:50:22So I think some of the data types we
5:50:23have already covered but still we need
5:50:25to understand some more. So first I'm
5:50:27just going to do drop table if exists
5:50:31and I'm just going to create one more.
5:50:33So I'm just going to do here basics dot
5:50:35let's give this one as maybe products
5:50:38basic. Okay. And then let's create the
5:50:40table. So we'll do create table and
5:50:44let's give this one as basics.
5:50:47dot product
5:50:50basic and then
5:50:52so we'll start with the first one which
5:50:54we've already covered. So this will be
5:50:56ID. So we're going to take serial and
5:50:58this will be primary
5:51:01key. Okay. Then next we are going to
5:51:04take our uh let's take a name property
5:51:07and here I'm just going to take one more
5:51:09uh prop uh thing here and that is called
5:51:11vare and I'm just going to give this one
5:51:13as 100. Let's do this one as not null.
5:51:16Now what actually we mean by this this v
5:51:19100 that we have taken here that means
5:51:20that we have a string with maximum
5:51:23length of 100 characters. Okay, so I'm
5:51:25just going to write here that we have a
5:51:27string that has a max length of 100
5:51:32characters. Okay, you need to use vare
5:51:36when you want to enforce a maximum
5:51:38length. Okay, so this is one more thing
5:51:41that you have learned. Now next thing uh
5:51:44let's take a description
5:51:47and for description I'm just going to
5:51:49take this one as text. Okay. So text is
5:51:52normal uh normally as string type. Uh
5:51:54what else? So let's take maybe a stock
5:51:56count. So I'm just going to take this
5:51:58one as stock and let's uh or let's do
5:52:00this one as stock. Maybe let's give
5:52:03stock only. And I'll do this one as
5:52:05integer and I'm just going to give a
5:52:07default value. Now we'll be able to also
5:52:08give a default value and this will be
5:52:10zero. Right? So integer is going to
5:52:13store a whole number right. So that
5:52:15means your stock should be a whole
5:52:17number 0 1 2 300 like that. It should
5:52:20not be 10.5 or 5.5. Okay, this is
5:52:23actually important when you're using
5:52:25integer. Then we have something called
5:52:27big int. So let's I'm just going to take
5:52:29a total property here or let's do total
5:52:31views or something like this. And I'm
5:52:33just going to give this one as big int.
5:52:35And then here also I'm just going to
5:52:36give this one as a default value which
5:52:39will be zero. Now what this big int
5:52:42means that we want to store larger whole
5:52:45number than integer. So we want to store
5:52:49larger whole number
5:52:53than integer right or we have integer
5:52:57something like this. So now in most of
5:53:00the times you'll see that your uh
5:53:02integer will be more than enough. Then
5:53:05we have one more property that you need
5:53:06to understand. Let's we have a price
5:53:08property and this is called numeric.
5:53:10Okay. So I'll do numeric and here I'm
5:53:12just going to give 10 2. Now what
5:53:14actually this is telling here this
5:53:16numeric is actually useful for your
5:53:17exact decimal values. So when you are
5:53:20going to use decimal values you want to
5:53:22take one minute. Okay. So you want to
5:53:26take numeric here. So this will be your
5:53:27exact decimal
5:53:30values. So what I mean by exact? So here
5:53:33uh we have 10. So 10 is what? 10 means
5:53:37your total digits. So 10 means total
5:53:41digits and then you have two. So two
5:53:44means here digits
5:53:47after the decimal point after the
5:53:51decimal
5:53:54point. Okay. So let's say you have 999
5:53:58something like this 999. Okay. So this
5:54:00is where you can take numeric and then
5:54:02at the end we have the boolean. So let's
5:54:05say I want to take is active something
5:54:07like this is active. So let's do is
5:54:09active and here I'm just going to take
5:54:11this one as boolean and here you can
5:54:13also take a default value and default
5:54:15value will be true. So this will be my
5:54:17default value and this will be a boolean
5:54:19property. Okay. So this is how you can
5:54:21create. Now here we don't have that much
5:54:24things to understand because these are
5:54:25very straightforward whatever things we
5:54:27have done. Now let's see want to let's
5:54:29write the queries also. So I'm just
5:54:30going to write the queries that I want
5:54:32to add some rows in this particular
5:54:36table. So how we can do that? We have
5:54:37already learned. So we can do insert and
5:54:39let's do into and we are going to do
5:54:42basics dot product basic and here let's
5:54:46say I wanted to render sorry enter name
5:54:50then we have what description then we
5:54:52have the stock then we have the total
5:54:54views right so I think we have taken the
5:54:56total views then we have the price and
5:54:59then at the end we have the is active so
5:55:02these all the things we want to render
5:55:03and what we want to render so we need to
5:55:05render the values correct And now let's
5:55:08say I wanted to add here. So let's add
5:55:12here something like this. Product one
5:55:15description. I'm just going to do
5:55:16product disk.
5:55:19Then we're going to give a uh stock
5:55:22count which will be what? So this will
5:55:23be whole number. Then we have the total
5:55:25views. So what is total views? Total
5:55:27views will begin. So you can take
5:55:29anything like 1200. Then you have the uh
5:55:32so after this so let's take the price.
5:55:35So price will be numeric right? So we
5:55:37can take something like 2 455.65
5:55:41and then we'll take true. Okay. So these
5:55:43values I want to insert. And let's say
5:55:46now at the end you want to also get the
5:55:48values here that how many uh um rows or
5:55:53products that we have added. So to do
5:55:54this what we can do simply we can do a
5:55:56select right and then we'll do start.
5:55:59Now remember I already mentioned all of
5:56:00this you can directly run for my psql
5:56:02command also that I've already showed
5:56:04you all of these but here I can I'm
5:56:06doing all of this at once. So I'll do
5:56:08basics dot product basics. So I'm simply
5:56:11telling that okay first create this
5:56:12table insert this particular data and
5:56:16then I'm going to get the data
5:56:17information. Now let's say uh you get
5:56:20one more requirement that you need to
5:56:22write a query where you are only going
5:56:24to get the active products. You have to
5:56:27get only the active products not all the
5:56:29products. Okay. So how you can do that?
5:56:32Now here you'll see that we have a
5:56:34boolean column that is is active. Right?
5:56:38This one what we can do that we can
5:56:39directly use in our filters. So
5:56:42something like this that where the field
5:56:44name which is is active is equal to true
5:56:46that is also valid. So let's see how we
5:56:49are going to do that. So here I'm simply
5:56:50going to do that. Okay. Select ID.
5:56:54Select name. Select price and select is
5:56:59active from. So you have to give from
5:57:02from where to place. So L basics.p
5:57:04product basics this is the table name
5:57:06and this is the condition. Then you're
5:57:08going to tell where is active is two.
5:57:11That's it. So this is going to give you
5:57:13all these data where is active will be
5:57:15true. Now let's see if this is working
5:57:17or not. Okay. So I'm just going to clear
5:57:19this and let's run again. And here. So
5:57:23first I'm just going to rename copy this
5:57:27and then I'm just going to paste it
5:57:28here.
5:57:32Okay, we are getting one error uh insert
5:57:34into basic. Okay, something I think we
5:57:37have missed here that is
5:57:41okay. We have to give this
5:57:44and also we have to give here also.
5:57:49So now let's clear this and let's run
5:57:52once again.
5:57:55All right. So now it's drop table create
5:57:57table one product is added and you can
5:58:00see that you're getting the information
5:58:02here that this is the one product. So
5:58:04this is from where you're getting this
5:58:05is the query and then you're getting
5:58:08only one product where it is is active
5:58:10because for now we have only one
5:58:11product. If you want you can add one
5:58:12more product that I will also give you
5:58:14as a home world. do one thing instead of
5:58:16adding one product here you can add
5:58:18multiple products right what you have to
5:58:21do in these values right instead of this
5:58:23you have to just give comma and then
5:58:25paste it one more time and then you just
5:58:26close with the semicolon you'll see that
5:58:28and for the second one just make this
5:58:30one to false and then when you're going
5:58:32to run this right so here you're still
5:58:34going to get only one result because
5:58:35that is only one product which will be
5:58:37true I hope you're getting right so try
5:58:38to do this one by yourself but for now
5:58:41for the basic data types this is more
5:58:43than enough so we have learned the ID
5:58:45one is the serial
5:58:47which is our primary key one is vare we
5:58:50have learned text integer begin numeric
5:58:52boolean so with this now let's move on
5:58:54to the next one where we are going to
5:58:56understand some of the other data types
5:58:57that is also very very important that
5:58:59you can use uh in some situations based
5:59:02on your project requirements so let's
5:59:03see how we going to do that in the next
5:59:05All right so moving to the next one so
5:59:06let's create the next file and this will
5:59:09be other
5:59:11data typesql
5:59:14Okay. So let's first create it. So I'm
5:59:16just going to do drop table
5:59:19if exists. And I'm just going to do
5:59:22again basics. This is our schema. And
5:59:24let's give this one as app events or
5:59:26something. And I'm just going to do
5:59:28create table. And I'll do basics dot app
5:59:32events. And here first of all what I
5:59:35will do right? So we are going to create
5:59:38our id as a uid. Okay. So how we are
5:59:41going to do that? So what actually first
5:59:43we need to understand what is UU ID
5:59:46means so it's a unique identifier type
5:59:48okay and here just like we have the
5:59:51serial right so this is not a simple 1 2
5:59:543 that you added three data and now you
5:59:56are adding the fourth data so the ID
5:59:58will become four so what will happen
6:00:00right it the values will look like a
6:00:02certain format okay and how we are going
6:00:04to create it so you have something
6:00:06called generate random UID okay which
6:00:09will going to create your random UID
6:00:12automatically. So how we are going to do
6:00:13that? So here we have ID and I'm just
6:00:16going to give this one as EU id and here
6:00:19so we're going to give this one primary
6:00:21key and you have to give a default and
6:00:23in this default you have to give this
6:00:24one as uh gen and then this will be
6:00:27random and then you're going to do UID
6:00:29and this is going to create a unique UID
6:00:32for this particular column. Okay. Now
6:00:35next let's take maybe we have a app
6:00:37events right? So let's take a event
6:00:39name. So I'll do event name and this one
6:00:42I'm not explaining. So this is text and
6:00:44I'm just going to do not null. And now
6:00:46what we're going to do right we'll
6:00:48understand one more new uh data type
6:00:50which is called JSON B. So what this
6:00:53JSON B means right now this is going to
6:00:56store your JSON data and this is going
6:00:58to store if I'm not wrong it's going to
6:01:00store in a binary format or binary
6:01:02optimized format. Okay. when you need to
6:01:05have some flexible structured metadata
6:01:07for that particular column, you should
6:01:08take this particular type. Okay. Now
6:01:10let's I'm just going to have a metadata
6:01:12and this metadata will be my type of
6:01:14JSON B and you're going to give a
6:01:16default value and in this default value
6:01:17I'm going to tell that okay this will be
6:01:19my default value for this particular
6:01:21metadata and this will be of type JSON
6:01:24B. I hope this is clear. Okay. So now
6:01:28next also I think time stamp we have
6:01:30already discussed still let's take it.
6:01:31So I'm just going to do create a and
6:01:33this will be a time stamp and I'm just
6:01:36going to give a default and this will be
6:01:38now. So which will be the current time
6:01:40and I think this is done. So now this is
6:01:42going to create our table. So this will
6:01:44be our this app events table. So if I
6:01:47save this and now let's go here. Let's
6:01:50run this. And now let's copy this file
6:01:54name first. we'll do slowly and then
6:02:01okay so it's created the table now what
6:02:03I'll do right so let's go here and then
6:02:07I'm just going to run this and also I'm
6:02:09just going to move this one here and
6:02:12then I'll be inside this and here what
6:02:14I'll do right so we have the DT and okay
6:02:18so we need to I think I always make this
6:02:20mistake we need to do DT / DT and we
6:02:24have to do basics because this is our
6:02:25schema dot start and this is going to
6:02:28give you all the uh table. So you can
6:02:30see that we have app events just now we
6:02:31have created product basics and the
6:02:34student and the same thing you can also
6:02:36check here also right if you go here and
6:02:38let's see if I refresh this I don't know
6:02:39why this is this much slow man it's very
6:02:41irritating see so if I refresh this
6:02:43right you'll be able to see all the
6:02:44updated tables you have app events and
6:02:46you can go here and you can explore all
6:02:48of this whatever columns that you have
6:02:50created okay id event name metadata
6:02:54created that is fine so now what I'm
6:02:56going to do right so first of all let's
6:02:58insert one of uh maybe let's insert two
6:03:02data here. So what I'm going to do
6:03:04simply here only I'm just going to do
6:03:05again we can do the same thing from here
6:03:07also I'm repeating the same same thing
6:03:09again and again the reason why I'm
6:03:11adding so that it will be easy for you
6:03:12to copy paste or else what you need to
6:03:14do right if I write all of these
6:03:16directly in command line not in this
6:03:18file so when you download the source
6:03:20code these queries will not be present
6:03:22you're getting uh what I'm explaining
6:03:24here so that is the reason I'm just
6:03:26writing all of this here so I'm just
6:03:28going to do insert into and I'm just
6:03:31going to do basics dot app events and
6:03:34here I'm just going to do the event name
6:03:35because we have the event name and we
6:03:37have to add the metadata correct so we
6:03:39have the metadata and here I'm just
6:03:41going to do values and let's add
6:03:44so here I'm just going to do maybe event
6:03:46right so maybe let's say sign up is one
6:03:48of the method and here now you have to
6:03:50add a JSON so this will be JSON property
6:03:53and maybe let's I'm just going to do
6:03:54sign up and this user sign up from uh
6:03:58Chrome browser something like this and
6:04:00so this will be browser and And this
6:04:02will be Chrome. Okay. So this will be
6:04:04your format. This is how we need to take
6:04:06it. Now let's see. I'm just going to
6:04:07copy this and then copy uh comma paste
6:04:11and then I'm just going to do sign in.
6:04:13And here I'm just going to do maybe
6:04:15browse and install browser. I'm just
6:04:17going to do username or whatever you
6:04:19want to take user and then I'm just
6:04:22going to take this one as someone. Okay,
6:04:24it can be anything. So this is now going
6:04:27to insert that into that particular uh
6:04:30app event table. So now to check it I'm
6:04:34just going to do a select query start
6:04:36and then I'm just going to do from and
6:04:38then I'll do basics do app event. This
6:04:40is the table name. So first let's do
6:04:42this and let's run it once again.
6:04:45So here I'm just going to run this and
6:04:48you can see that so we have created this
6:04:50inserted and you can see that we getting
6:04:52UID. This is the UID. This is the format
6:04:54that I'm talking about. This is the
6:04:56event name sign up and this is the
6:04:57metadata and then you have the time
6:04:59stamp. Okay. And this is the second one
6:05:02for sign in. So what we are
6:05:03understanding that whether it is
6:05:05creating the UID not it's actually
6:05:06successfully created this UID. Now what
6:05:09you can do right you can also query
6:05:11these JSON properties also or JSON field
6:05:14also. How? So now let's say uh maybe
6:05:17what I'm going to do right I have this
6:05:19browser. Correct? So now this browser I
6:05:22wanted to check that what I wanted to do
6:05:25here that I want to open my JSON B
6:05:27column named metadata right so we have
6:05:30given the metadata right and now here
6:05:32let's I wanted to get the value of this
6:05:34browser this browser as text so how I'm
6:05:38going to do that to do this what you
6:05:40have to do right so you have to do
6:05:41select and then I'm just going to give
6:05:43an event name
6:05:46now this is the important part so you
6:05:47have to give metadata and here you're
6:05:49going to give like this. So now this
6:05:52metadata I'm simply telling that okay
6:05:53you have to find this browser property.
6:05:56Okay so we going to give this one
6:05:58browser. So it's going to find and then
6:06:00I'm just going to do give me as browser.
6:06:05Then this is not it because you have to
6:06:07always give your destination that from
6:06:09where you are going to find this. So you
6:06:10have to give from table name. We'll do
6:06:12basics.app events and here we are going
6:06:15to simply mention where metadata
6:06:20is browser.
6:06:23Okay, that's it. So what we are simply
6:06:26telling here this metadata uh this arrow
6:06:30browser means that you have to open this
6:06:32JSON column named as metadata and get
6:06:35the value of the browser as text. All
6:06:38right. So now let's test it. So first
6:06:40let's open this and I'm going to clear
6:06:42this and also in the meantime let's do
6:06:45one thing let's comment out this one.
6:06:47Okay so I only wanted to check this this
6:06:49part. So here what I'll do let's uh
6:06:53sorry not clear let's run it once again
6:06:56and you can see that what you're getting
6:06:57we are getting sign up and you're
6:06:59getting chrome. Okay so now what is
6:07:01happening here you're getting the sign
6:07:03up and this is chrome. Why? because we
6:07:05are clearly telling here that you have
6:07:07to open the JSON B column named metadata
6:07:10and you have to get the value of browser
6:07:13as text. So this is how you can do this.
6:07:15Okay. So this is about the other data
6:07:18types. Now next we have another very
6:07:20very important and that is how we are
6:07:21going to
6:07:23work with null, empty, string and zero
6:07:26value. Okay. So we have null, empty,
6:07:28string and zero value and all three are
6:07:31not same. So let's see how uh we are
6:07:33going to do that. So first of all I'm
6:07:34just going to do 06 maybe and let's do
6:07:37null
6:07:38empty string
6:07:41uh something like this or let's do
6:07:45zero also 0.sql is given. Okay. So first
6:07:50of all let's clear this.
6:07:54I'll close everything else. So first we
6:07:57have null, right? So null means unknown
6:08:02or missing value. Next we have empty
6:08:06string. Empty string will be what? known
6:08:11string value but no characters or but it
6:08:16contains no characters
6:08:20and then at the end you have the zero.
6:08:22So zero will be your actual numeric
6:08:25value, right? So actual numeric
6:08:29value of zero. Okay. So let's create one
6:08:34more uh here. So I'm just going to
6:08:35copyright instead of rewriting. So copy
6:08:37this, paste it here and this I'm just
6:08:40going to do value examples something
6:08:43like this and then I'm simply going to
6:08:45create. So do create table basics dot
6:08:49value examples and here I'm just going
6:08:52to do so now I'm doing little faster not
6:08:55already you have done multiple times. So
6:08:56do serial so primary
6:09:00key and then after this maybe let's take
6:09:04what is it? Let's take a nickname. So
6:09:06we'll do nickname which will be text and
6:09:09then I'm also going to take a bio which
6:09:12also will be text and let's take a score
6:09:16and this one I'm just going to do
6:09:17integer. Okay. So we have these three
6:09:20that's it. So now let's do one thing
6:09:22what we are going to do right here. You
6:09:24have to understand that when we are
6:09:25going to insert the value then you can
6:09:27clearly understand what is happening
6:09:29here. And I'm going to make these things
6:09:30very very simple and easy to understand.
6:09:33So I'm just going to do insert. I'll do
6:09:34into and I'll do basics dot value
6:09:37examples. So we have nickname, we have
6:09:40bio should be in that order. Okay. And
6:09:42then we have score. Correct? And then
6:09:44we're going to add values. Now you see
6:09:46what we are doing here. So for the first
6:09:48one, notice for the nickname I'm passing
6:09:51explicitly as null. Okay. And then I'm
6:09:53just going to do here by learning rej
6:09:58or maybe learning posgress.
6:10:01Right? And then I'm passing the score.
6:10:03I'll pass in 10. So this is my first
6:10:05one. Now here clearly I'm mentioning
6:10:08that nickname is null.
6:10:11Nickname is null. Right?
6:10:14Uh also let's move it here. So this will
6:10:17be the first one. First condition. Next
6:10:19what I'm going to do give comma and I'm
6:10:22going to add one more property. Sorry uh
6:10:24row here. Here I'm explicitly mentioning
6:10:27that nickname is empty string. See, I'm
6:10:29giving here empty string and I'm just
6:10:31going to do empty nickname
6:10:34and let's give 20 and then at the end uh
6:10:38what I'm going to do right so let's do
6:10:41here some names I'm just going to do sum
6:10:44and for the second one I'm going to pass
6:10:46empty and here for this score I'm giving
6:10:49explicitly zero so here what this is
6:10:52this means the score is zero this is not
6:10:54missing there is a huge difference
6:10:56missing means it's a null value. Zero
6:10:59means you're telling that okay he got
6:11:01zero in the exam. So it's a real number.
6:11:03Okay. So this is the difference. And
6:11:05then you can also pass multiple as a
6:11:07null also. Let's say you are passing
6:11:09here uh one more here that this guy is
6:11:12John and his bio is null and his score
6:11:16is also null. This also you can do.
6:11:19Okay. And this is done. So now this is
6:11:21going to add these four. Now what I
6:11:23going to do right? First of all, let's
6:11:24say I'm now from this point, right? We
6:11:27have already done all the queries and
6:11:29everything multiple times. You should be
6:11:31able to write some of the basic queries.
6:11:33For example, now I want to query all
6:11:35these values from my DB. How I'm going
6:11:36to do that or from that column? So, it's
6:11:38very simple, right? I'm just going to do
6:11:39select
6:11:41uh star. So, star and then I'm just
6:11:44going to do what? From so to give basics
6:11:47dot value examples. So, this will be the
6:11:50first thing. So if I save this and then
6:11:53let's say I'm just going to run it here.
6:11:56So this will be the null empty sorry
6:12:03and let's remove this
6:12:07and you can see that these two null this
6:12:10also whenever you're getting empty or
6:12:11null you're getting those columns are
6:12:13empty right so that mean this is working
6:12:15fine now let's say you only want to
6:12:18check that maybe I want to check that
6:12:20give me the records where the nickname
6:12:23is only null so how you can do that so
6:12:25I'm going to comment it out here. So I'm
6:12:27just going to tell that okay select star
6:12:30from
6:12:32basics do app sorry not app value
6:12:35examples and then here I'm simply going
6:12:37to do that where nickname
6:12:42will be what is null simply so this is
6:12:46going to give me that okay give me from
6:12:47this table where the nickname is null so
6:12:49this is going to give me all the
6:12:50examples where the nickname is null and
6:12:52you can run it once again so let's say
6:12:55if I just run it Here you can see that
6:12:57we have only one where the nickname is
6:12:59null. Okay. Then you can also do maybe
6:13:02let's say you want to see where the
6:13:04nickname is empty. So I'm just going to
6:13:06do this will be a homework that write
6:13:08one query
6:13:11to find where nickname is empty string.
6:13:18So this will be your homework. Okay. Try
6:13:20to do it by yourself.
6:13:22Now let's say you want to check whe the
6:13:24score is only zero. So to do this you
6:13:26can do select star. So I do from basics
6:13:30dot value examples and then you're going
6:13:33to do where score will be equal to what?
6:13:36Zero. That's it. So this is going to
6:13:37give you where the column the score is
6:13:40zero. And if you run this here once
6:13:41again
6:13:44and you can see that you're getting this
6:13:46right. So that means this is working
6:13:49fine. And this is how you have to use.
6:13:52Now you also can use reverse way that
6:13:55you want to check whe the nickname is
6:13:57not null. Okay, I'm going to repeat once
6:14:00again. You want to check whe the
6:14:01nickname is not null. So how you can do
6:14:03that? Copy this exact thing. Paste it
6:14:06here and you're going to do is not null.
6:14:08Okay, so this is where it's going to
6:14:10give you the reverse uh result. So here
6:14:13I'm just going to do clear and let's run
6:14:15once again.
6:14:17You can see that you're getting nickname
6:14:20is not null. Okay. Now here okay first
6:14:23we are getting three but for the first
6:14:25one it is null right. How many we have
6:14:28added? Let me just check. Okay we have
6:14:30added four correct. So it should be
6:14:32getting three because first one is
6:14:33explicitly null second was not empty. So
6:14:37this is different. Okay. So here it's
6:14:39going to give you that where it is not
6:14:41null. I hope this is clear right? So we
6:14:44are not going to use equal to null. we
6:14:45are going to use if not null something
6:14:47like this. So I think this is all what
6:14:50else uh I think I think yeah okay one
6:14:55more thing I wanted to mention I think
6:14:56that part we have covered right the
6:14:58empty one we have covered is null we
6:15:00have covered yeah I think we have
6:15:01covered almost all the things so try to
6:15:04practice this one the reverse one that
6:15:06when you want to check that if there is
6:15:0810 products or 10 uh examples that rows
6:15:12that are added in that particular table
6:15:14so there can be two scenarios you can
6:15:16check you want to check the products
6:15:19where it is null. So you're going to do
6:15:20where that particular key name is null.
6:15:23If you want to check the reverse, you
6:15:24have to give where the key proper key
6:15:26name is not null. Okay, it's going to
6:15:28give you the reverse order. So with this
6:15:30now, let's move on to the next one. Next
6:15:31one, we're going to understand what is
6:15:33constants. Okay, and this is also very
6:15:34very important. All right. So moving to
6:15:36the next one. Another important concept
6:15:38which will be constants, right?
6:15:42Uh let's do this one as SQL.
6:15:46All right. So close this. So we have
6:15:48different column constants. Okay. So we
6:15:51have something like I think we have
6:15:52already discussed not null. Then we have
6:15:55unique
6:15:57then you have default then you have
6:15:59check all these right now these all are
6:16:03database rules. Now why this is very
6:16:05very powerful because it's going to
6:16:08protect your data and user will not be
6:16:10able to pose wrong data to D. You can do
6:16:14backend validation because backend
6:16:16validation always you need to do it. But
6:16:18remember one thing and this is also very
6:16:20important concept that you should know
6:16:21if you're a beginner let's you are
6:16:23working in sorry you are studying in
6:16:24college that even though backend
6:16:26validations are good but database
6:16:29constants are always always stronger
6:16:31than backend validation. Why? Because
6:16:33that is going to directly protect the
6:16:35data even let's say uh you are writing a
6:16:39different app or script or developer
6:16:41whatever they are doing. So you're
6:16:43you're understanding what I'm saying. So
6:16:46you have a back end logic or back end
6:16:48validation logic in your back end code.
6:16:50Now let's say you don't have any
6:16:52constants in your DB. Now if we can
6:16:55write in our DB in different ways,
6:16:57right? So what I mean by this, we can
6:16:59write in a different ways. You can write
6:17:00from your app. So let's say you're doing
6:17:02some API call and API call is writing
6:17:04into your DB. You can also write uh data
6:17:07into DB using script or directly
6:17:10developer can go to DB and they can
6:17:12write makes sense right easily we can do
6:17:14it but let's say if you have constant on
6:17:17the DB level in all scenarios if you're
6:17:20writing a wrong data it's going to fail
6:17:23so that is the reason backend validation
6:17:25sorry database constants are always
6:17:27always always stronger than backend
6:17:29validation doesn't mean that I'm telling
6:17:31that you don't have to write backend
6:17:32validations you have to write but both
6:17:34are equally important important but
6:17:35database constants are much stronger
6:17:37okay whenever you'll be working with
6:17:39databases so first let's do one thing so
6:17:41I'm just going to do here let me just
6:17:42copy from here so I'm just going to copy
6:17:45this paste it here and let's give this
6:17:47one name as basics dot let's create
6:17:49accounts and here I'm just going to do
6:17:51create table and I'm just going to do
6:17:54basics dot accounts and let's add ID
6:18:00let's give this one as primary Okay,
6:18:05let's add a full name. So I'm just going
6:18:08to do text and this will be not null.
6:18:11Okay, so this is one of the constant. So
6:18:14not null means we're simply telling that
6:18:15full name is required and postgress is
6:18:18going to reject whenever we going to
6:18:20insert and we'll see that if the full
6:18:22name is missing as simple as that. What
6:18:24else? Uh I think unique we have already
6:18:26discussed right still let's do it. So
6:18:28I'll do email. This will be text. And
6:18:31I'm just going to do not null. And this
6:18:33will be unique. And also we are going to
6:18:36give a default value. So I'm just going
6:18:38to do isore active. And I'm just going
6:18:41to do this one as boolean. And this will
6:18:43be default. And I'm just going to give
6:18:45this one as true. Okay. And check also
6:18:48we have discussed previously. So I'll do
6:18:50integer. And I'm just going to take a
6:18:52check. And here I'm just going to give
6:18:54age should be greater than or equal 80.
6:18:58Okay. And let's take the last one which
6:19:00will be created at and here I'll do this
6:19:05one as time stamp. We also have a time
6:19:07stamp Z. There is one more property and
6:19:10then we're going to take this one as
6:19:12now. Okay. So this is going to create
6:19:14our table. All right. Now let's do some
6:19:17of the valid insert. Okay. So valid
6:19:19cases. So let's I'm just going to do
6:19:21insert into
6:19:25here into. So I'll do basics dot
6:19:28accounts. So we have full name. We have
6:19:31email and let's do age is active we
6:19:34don't have to do because it's given as
6:19:36default. And I'm just going to do
6:19:38values. And I'm just going to add my
6:19:39name here.
6:19:42And let's give the email.
6:19:46And I'm just going to give the age.
6:19:48Let's do 11. Okay. That's it.
6:19:52So now let's save this. And we are going
6:19:54to run this file.
6:19:56Okay. So, let's copy this
6:20:02and we'll go here and then I'm just
6:20:05going to replace this.
6:20:11Okay. What is telling that no new row
6:20:13for relation while check constant
6:20:16account? Oh, see we are already getting
6:20:17added. Fantastic. Because we have given
6:20:19this one as 11, right? So, it should be
6:20:21greater than 20 uh sorry 18. So we have
6:20:24to give this one as 20. All right. So
6:20:26it's already working. You can see that.
6:20:29And I didn't give this one
6:20:30intentionally. So I missed it. So now it
6:20:32should be able to. So you can see that
6:20:33it's working, right? And if you want to
6:20:35get it the data, what you can do? Simply
6:20:38do select start from and you'll do
6:20:40basics dot accounts, right? And this is
6:20:43going to give you the information.
6:20:44Again, I'm repeating the same thing you
6:20:46can do from where? From your ESQL uh
6:20:49terminal also, right? So if you run
6:20:51this, you can see that you're getting
6:20:52one data. Fantastic. Right. So now what
6:20:55you're going to do, right? So see what I
6:20:57mean. Right. So you can directly do from
6:20:58your uh this psq alg. So let's see if I
6:21:01clear this and then I'm just going to go
6:21:04here copy this.
6:21:07Okay. Now inside this let's say you want
6:21:10to get the data from this accounts
6:21:11table. So what you can do? You can do
6:21:12directly just select start and then
6:21:15you're going to do from and you'll do
6:21:17basics,
6:21:18right? And then you'll do accounts.
6:21:20That's it. And if you enter here, you're
6:21:22going to get the same result. So now
6:21:24you're understanding why I'm not doing
6:21:26here all the things because if I do
6:21:28here, you will not be able to get it
6:21:30from the source code. So here you'll be
6:21:32able to see the exact queries, right? So
6:21:33that is the reason. But these are
6:21:35optional. These are not needed. I'm
6:21:37repeating this thing so many times
6:21:38because some of you can be quite
6:21:40confused that why he is writing these
6:21:42queries inside this file. That is
6:21:44actually intentional. So I'll clear
6:21:47this. So this is working fine. Now let's
6:21:49say I'm going to give some invalid
6:21:50scenarios now. So what I mean by invalid
6:21:52scenario so that we can check. So first
6:21:54one will be let's say I I I I will be
6:21:57adding the email and age. I'm not going
6:21:59to add the full name. But if you see the
6:22:02rule right full name is not null. So
6:22:04that means we need to add it. So this
6:22:06should fail and you'll see that it is
6:22:08going to fail. So I'm just going to
6:22:09comment it out from for uh now copy this
6:22:12comment it out and then let's paste it
6:22:15here and then I'm just going to remove
6:22:17the full name. I'm going to keep the
6:22:18email and I will just give here missing
6:22:23name at thegmail.com 20. And then if you
6:22:26try to run this and you'll see that this
6:22:28is going to fail for sure. And you can
6:22:31see that this full name null value in
6:22:33the column full name relation accounts
6:22:35violates not null constant. Correct? So
6:22:38this is another fail case scenario. What
6:22:41else? All right. So let's add one more
6:22:43case. So what we can do right maybe I'm
6:22:44just going to okay let's copy this
6:22:48and I'm going to comment it here. Let's
6:22:50remove this comment and I'm going to
6:22:52paste it one more time. Okay. And see
6:22:54what we are doing here. So I have sa
6:22:56mukari sangamgmail.com
6:22:58and I'm going to take uh duplicate
6:23:02email user and I'm going to keep the
6:23:05same email. Maybe let's do this one as
6:23:0723. So this also should fail. Why?
6:23:10because we have two user with same
6:23:12email. Okay. So let's run this and you
6:23:16can see that we have duplicate key for
6:23:17this unique. So account email key. This
6:23:20is also another constant. Okay. So
6:23:22similarly you can check multiple
6:23:24scenarios here. For example, let's say I
6:23:27we have already checked right. So if you
6:23:28give the age less than 18 so it's going
6:23:31to fail. For example, let's say I'm
6:23:32going to do sum one. But at the same
6:23:34time, I'm going to make this one as
6:23:36three or maybe let's say uh five.
6:23:38Whatever you want to do, this is also
6:23:40going to fail, right? So let's say clear
6:23:42this and try to push. And you can see
6:23:46that what you're getting the account age
6:23:48check constant. So this is failing. Why?
6:23:50Because the age is five and in the
6:23:52constant we have clearly given the check
6:23:53should the age should be greater than or
6:23:55equal to 80.
6:23:58So this is the concept of constant. So
6:24:00this is how you need to use right. So I
6:24:02think we have covered all the things and
6:24:04one thing we need to understand and that
6:24:06is uh some more about primary keys that
6:24:08we are going to discuss in the next part
6:24:10and then we'll move to the part two.
6:24:12Why? Because for part one we have almost
6:24:14covered most of the things and in
6:24:16details right I'm pretty sure you will
6:24:17not find this kind of explanation in
6:24:19paid courses also because I'm explaining
6:24:21each and everything slowly and once you
6:24:23do the practice right you'll be able to
6:24:25understand you'll not going to forget
6:24:26you're not going to believe me that when
6:24:28I usually learn all these things right I
6:24:30took things very very seriously even if
6:24:32I learn all these things five years back
6:24:34right the way I've learned things I I
6:24:36never memorized these things right so
6:24:38maybe there is a possibility that I
6:24:40won't be able to memor uh like recollect
6:24:43the uh let's say the syntax and
6:24:45everything because it's not possible for
6:24:47everyone to remember everything right
6:24:49but once I'll see once right maybe let's
6:24:52say 5 years back I've done SQL I'm just
6:24:54giving example and after 5 years I'm
6:24:55just I need two three days and I'll be
6:24:57able to again implement project from the
6:25:00next day so this is how you need to
6:25:02learn all these things so with this now
6:25:03let's move to the next one all right so
6:25:05let's finish our part one with little
6:25:07more concept that we are going to cover
6:25:09that is on primary keys
6:25:12So let's create primary is dosql.
6:25:17I think this one we've already discussed
6:25:18that primary key is going to denotes
6:25:20that it's uniquely identifies each row
6:25:23in a table. Okay. Now if you don't have
6:25:26any primary key what are the things that
6:25:28will become difficult. Now these can be
6:25:30interview questions also. So if you
6:25:32don't primary key it becomes harder to
6:25:35update, delete, do any kind of reference
6:25:39or even if you want to connect to a
6:25:41specific row to rows in other tables.
6:25:44All these things can be very very
6:25:46tricky. Okay. So that means there has to
6:25:48be something unique in each and every
6:25:50row so that you'll be able to identify
6:25:51that particular row which is what your
6:25:54primary keys is going to do. Okay. So
6:25:56here now let's do one thing. I'm just
6:25:58going to do drop table. I'm just going
6:25:59to create a simple table. I'm just going
6:26:01to do if exist. So let's do basics dot
6:26:04uh what we can do maybe let's do courses
6:26:08courses or maybe let's do sales
6:26:11then I'm just going to do create table
6:26:14and I'm just going to do basics dot
6:26:16sales and here I think we have already
6:26:19discussed I'm not explaining because we
6:26:21have already covered so we have a ID
6:26:23which is a serial and this will be my
6:26:25primary key okay and then let's say you
6:26:29want to do title sorry sales name maybe
6:26:32let's do title or whatever you want to
6:26:34take. So I'm going to take text. This
6:26:36will be not null. And what else you can
6:26:39take? Uh maybe let's do one price
6:26:42property sales price. And I'm just going
6:26:45to do this one as numeric.
6:26:49So let's do 10, 2. And here I'm just
6:26:52going to do this one as not null. And
6:26:54also I'm going to give a default value
6:26:55of zero. And let's take one more which
6:26:58will be created at. So this will be
6:27:00timestamp and I'm going to do default
6:27:02and this will be now.
6:27:06Okay. Now let's add some value here. So
6:27:09I'm just going to do insert into
6:27:12basics dot sales. So what are the things
6:27:16we have? We have the title and the
6:27:17price.
6:27:19And let's add here some values.
6:27:24So let's add maybe sale one. And I'm
6:27:28just going to do cell 200. Let's give
6:27:31comma. So I'll do cell two. And let's
6:27:35give this one as 500. Something like
6:27:37this. Okay, this is done. So save this.
6:27:40And let's run it here. So I'm just going
6:27:42to clear,
6:27:45rename, copy this, and then I'm just
6:27:49going to run it. So it's going to create
6:27:51the table.
6:27:53All right. Fantastic. So now let's say
6:27:56first of all I wanted to check that what
6:27:58I have here. So I'm just going to do
6:27:59select star from sold basics dot cells
6:28:06save this and let's run once again.
6:28:11So you have two data okay so ID 1 and
6:28:14ID2. So till this part this is fine
6:28:16right now what we can do right we can
6:28:18also query based on the ID. So now let's
6:28:21say I only wanted to see the data of
6:28:25ID2. So I can simply do your select
6:28:27start and you can do from you do basics
6:28:30dot sales
6:28:32and here you have to give where your ID
6:28:34will be equal to two. So this is going
6:28:37to give you the second information
6:28:38second row information. So if you clear
6:28:41and run this you're going to get only
6:28:43one. Okay. Now one thing is very
6:28:47important. And now let's say I'm going
6:28:48to give a invalid scenario here. So
6:28:51let's do one thing, right? What we are
6:28:53going to do maybe uh okay let's do one
6:28:56thing. Let's keep this one like this and
6:28:58let's comment it out. And I'm going to
6:28:59insert one more data here. Okay. So I'm
6:29:02just going to do here. Let's copy this
6:29:04only from here. Paste it. And I'm just
6:29:07going to do insert into basic uh dot
6:29:09quotes. Sorry. And here I'll do ID,
6:29:12title, and price. All three things I'm
6:29:14adding in the values. Let's I'm going to
6:29:16add only one value. But see what I'm
6:29:18doing in the ID I'm giving a duplicate
6:29:20ID. So here I'm giving one. Why? Because
6:29:22see if you notice here this one ID will
6:29:25be automatically created before only. So
6:29:27here I'm just going to giving it
6:29:28duplicate ID and you'll see that this is
6:29:30going to fail. Okay. So I'll do
6:29:32duplicate
6:29:35ID something like this. And if you now
6:29:38save this right and see what will
6:29:40happen. So I'm just going to clear this
6:29:43run it and you can see that your
6:29:45duplicate key value violates unique
6:29:47constant sales primary key fantastic key
6:29:50ID equal to one is already exist. So
6:29:52this is a proof that your primary key
6:29:55will be always unique and primary key is
6:29:57going to denotes that okay this is my
6:29:59unique identifier for each row in a
6:30:01certain table. So with these the first
6:30:04basic things we have covered I think we
6:30:06have learned a lot of things these
6:30:07things are very very important without
6:30:08these we can't move to the next section.
6:30:10So with that now let's move on to the
6:30:12part two. Okay. All right everyone. So
6:30:14now it's time to start on the part two.
6:30:16So what actually we are going to cover
6:30:17in the part two. So part two will be
6:30:19more on more SQL basics and the concepts
6:30:21we are going to cover. For example let's
6:30:23say what is the concept of so I think
6:30:25insert we have already covered in uh
6:30:27still we are going to cover insert
6:30:28single row multiple rows how you're
6:30:31going to select specific columns. Uh
6:30:33[snorts] where and basic filters then
6:30:35you have and or not right like I like.
6:30:39So many things are there. So all those
6:30:41things we are going to cover in this
6:30:42part two. So for this one what we're
6:30:44going to do right we'll be having a
6:30:45setup file. So what this setup file is
6:30:47going to do this setup file is going to
6:30:49create the table and based on this
6:30:51particular setup file whatever concept
6:30:53that we are going to cover in the next
6:30:54section we are going to use this
6:30:56particular table as a base table. Okay.
6:30:58Now the reason is very simple. So I'm
6:31:00going to show you if you search on
6:31:03Google right postgress SQL mac and
6:31:05everything you'll see that it has lot of
6:31:06issues also and it's extremely slow. I
6:31:08don't know why I think if you're using
6:31:10Windows right you will not face this
6:31:12issue. So what I'm trying to explain
6:31:13that if you want to visualize all those
6:31:15data from your posgress also you can
6:31:17easily do that. But as I already
6:31:19mentioned that we are going to use a
6:31:20terminal only or let's say psql command
6:31:23line which is much better. I will say
6:31:25which is better because it will give you
6:31:27much more better idea how we can write
6:31:29commands and everything. So first let's
6:31:31start with create. So I'm just going to
6:31:33do this one as 0 0 or let's do 01 and
6:31:36I'm just going to do SQL concepts
6:31:40base file. Okay. So I'll do base files
6:31:42SQL. All right. So first let's create
6:31:45some of the tables and everything. And
6:31:47for this one I'm not going to explain
6:31:48each and everything because some of the
6:31:50things we have already covered. So let's
6:31:52start with first I'm just going to do
6:31:53create extension
6:31:58extension spelling. Okay. It's correct.
6:32:00So I do if not exist and I'm just going
6:32:03to take pgto.
6:32:06So after this I'm just going to do a
6:32:08drop table if exist. Let's give this one
6:32:11as products
6:32:13and then let's create our table. So I'm
6:32:15just going to do create table and I'll
6:32:17do this one as products. Okay. Now let's
6:32:20see what are the things that we are
6:32:21going to take. So first let's take ID
6:32:23and remember all these uh properties
6:32:25that we are going to take right you have
6:32:27to recolct because whenever we are going
6:32:29to cover the next concept we are going
6:32:31to use this table as a base table. So
6:32:33I'm just repeating this thing multiple
6:32:34times. This is important. So we are
6:32:36going to take this one as UID and I'll
6:32:38take primary key. Let's take default and
6:32:41for this one I'm just going to do gen
6:32:44random UID. I think this we have already
6:32:46covered.
6:32:48Next let's take a name property. So name
6:32:50I'm just going to take this one as text
6:32:52not null.
6:32:56Next let's take a category. So this also
6:32:58I'm going to take as text not null.
6:33:03Let's take a price. So for price I'm
6:33:05just going to do this one as numeric
6:33:08and this I'll do 10A 2 not null and
6:33:13let's give a check. So for check I'm
6:33:16just going to do price
6:33:18has to be greater than or equal zero.
6:33:20Okay. So this is one check I'm giving.
6:33:22Then let's take a stock.
6:33:25I'm just going to do this one as integer
6:33:27not null. I'll do default. Let's give
6:33:31default as zero and check. So here also
6:33:34I'm just going to give the stock also
6:33:35has to be positive. So it will be
6:33:36greater than or equal zero. Then let's
6:33:40take a is active which will be boolean
6:33:44not null also. And then I'm just going
6:33:46to do a default which will be true.
6:33:48Okay. Let's take a skew property and I'm
6:33:52just going to do this one as text. But
6:33:54for this one I'm going to take this one
6:33:55as unique. So for every product there
6:33:57has to be one skew which will be unique.
6:34:00Then let's take a description.
6:34:02This will be text. And at the end we're
6:34:04going to take created_.
6:34:08And let's take this one as time stamp
6:34:10not null and I'll do default. Let's give
6:34:13the current time. Okay. So these all the
6:34:16properties that we are going to have or
6:34:18all the columns for this particular
6:34:19table. Okay. So first let's save this
6:34:21and let's see if this is working or not.
6:34:23So first what I'm going to do right?
6:34:25Let's copy this. All right. So now let's
6:34:27paste it here. So what we have done the
6:34:28same command we just have to go to part
6:34:30two and then this is the first file and
6:34:32then run. And you see that this is going
6:34:34to create the table. And then
6:34:35[clears throat] I'll just do clear and
6:34:38let's go here and let me quickly refresh
6:34:40this.
6:34:44See the how much uh slow this is. I
6:34:47think they have created this one using
6:34:49electron framework. This is what I'm
6:34:51thinking. And there must be some issue
6:34:52in the math specially. And if you go to
6:34:55public
6:34:58and then let's go to table. So you can
6:35:00see that we have products. And if you go
6:35:02to columns
6:35:05and you're going to see all these
6:35:07columns, right? So this is the columns
6:35:08that we have created. Fantastic.
6:35:10So now what I'll do, right? So let's
6:35:12insert some of the data first. So
6:35:16here I'm just going to do insert into
6:35:20products.
6:35:22So what are the things we have to do? So
6:35:23we have the name, we have category, we
6:35:25have price, we have uh stock, uh we have
6:35:30is active skew and also we have
6:35:33description. So these many things we
6:35:34need to uh add and then I'm just going
6:35:37to take this one as values and then I
6:35:40already have some data that I have
6:35:41created. Okay, this is the data that I
6:35:43wanted to add here. So copy this and
6:35:46after this I'm just going to paste it
6:35:48here. Okay, so this is what we are going
6:35:51to add. So now also let's do one thing.
6:35:54Let's run this command so that we can
6:35:56see that if these datas are present or
6:35:58not. So this is just a simple select
6:36:00command. So do select start from
6:36:03products.
6:36:04Save this and then we going to run once
6:36:07again.
6:36:09See that we are already getting the data
6:36:11here. Right? So this is all the data. So
6:36:13now what we need to do right using this
6:36:15data now we are going to understand all
6:36:16the concepts one by one. So let's clear
6:36:19this
6:36:22and let's start with the first one. So
6:36:24first will be I'm just going to do 0 to
6:36:26although with this one we have already
6:36:28done but I just wanted to still uh do
6:36:30this one more time. So I'm just going to
6:36:32do insert single row dosql.
6:36:36So how we going to do insert single row?
6:36:38I think this you have already know. So
6:36:41we just have to do insert into
6:36:45the table name. So you have products
6:36:46correct and then you have to give all
6:36:48the properties. So just now we have
6:36:49done. So we have name, we have category,
6:36:52we have price, we have stock,
6:36:55we have uh skew
6:36:58and also let's say I wanted to add
6:37:00description. Okay. So these many things
6:37:02we have right why is active is not
6:37:05needed because we have a default value
6:37:06here. Okay. This also have but let's say
6:37:08I wanted to so what will happen right?
6:37:10If you don't add this is active it will
6:37:12automatically take that one as true. So
6:37:14this is done. So now what we need to do?
6:37:16So let's add values and then let's add
6:37:19all the values that we wanted to add. So
6:37:22here also one more thing that each value
6:37:24that we are going to add that always
6:37:26should match or must match the column
6:37:29that we have added in the above. This is
6:37:31also very very important. So let's I'm
6:37:33just going to do here laptop lap laptop
6:37:37stand,
6:37:38category. Let's give this one as maybe
6:37:40electronics.
6:37:42Then I'll give comma let's give a price
6:37:43of 5,000.
6:37:460. Then after this I'm just going to
6:37:48give stock of let's say 23. Then I'm
6:37:51just going to do skew. Now this will be
6:37:53important. Okay. So let's see what are
6:37:55the skew that we are using. You see all
6:37:56these skew that we are using here.
6:37:58Electronics key 001 like this. So here
6:38:02maybe I'm just going to do electronics.
6:38:04So which one we can do? Electronics key
6:38:06002. Something like this. If it is
6:38:08you're giving wrong or if it is not
6:38:10unique then it's going to fail. So here
6:38:12I'm just going to do electronics key 002
6:38:17then I'm just going to give a
6:38:18description. So let's give this one as
6:38:20laptop
6:38:22stand description.
6:38:25Okay so this is done. So now first of
6:38:27all what we going to do right? So I'm
6:38:29just going to run this command. So first
6:38:31I'll copy this rename this. Sorry not
6:38:34rename. I'm going to copy this and then
6:38:36I'm going to run this here. Again, I
6:38:38already mentioned you can run the same
6:38:39thing in in your psql also.
6:38:44Okay, we are getting no y.
6:38:50Oh man, I have to put this one inside.
6:38:54So, let's try once again.
6:38:57So, you can see that inserting is done.
6:38:59So, now this will be your homework from
6:39:01this part because we have already
6:39:02covered. Now let's say I only wanted to
6:39:05check that if this data is present or
6:39:07not. Right? So here what I need to do so
6:39:10let's I'm just going to do select star
6:39:12then I'm just going to do from I have to
6:39:15give this products and then I need to to
6:39:17check so I need to give a where where
6:39:19the skew will be what the skew that I
6:39:21have given here because this is always
6:39:22unique. So this is going to give me the
6:39:24correct information always right and if
6:39:26I save this and let's say if I run it
6:39:28here so it should give me that
6:39:30particular result right what is syntax
6:39:33error oh you have to give this sorry my
6:39:36bad save clear and let's run again you
6:39:40can see that what you're getting
6:39:42duplicate key while let's this one this
6:39:44is already exist okay this we have
6:39:45already added my bad so here we just
6:39:47have to comment it out save it and now
6:39:50let's run it again and then you're going
6:39:53going to get one result. Okay. So you
6:39:54see that you're getting this result.
6:39:57So you have this UID laptop stand
6:40:00electronics 523. This is true. This is
6:40:03your skew 002 laptop stand description.
6:40:06This is your time stamp. So that means
6:40:08this is working fine. You're getting why
6:40:10you got that particular error because
6:40:12we've already added this and then we try
6:40:14to run this particular command but in
6:40:16before it's try to execute this
6:40:18particular query once again and then it
6:40:21check that okay there is a key that is
6:40:23already present because we already done
6:40:24this one in the before right so that is
6:40:26the reason we have to comment it out and
6:40:28then you have to do here now let's say
6:40:30you want to do like this let's say you
6:40:32want to check that I wanted to check if
6:40:34something is present with electronic key
6:40:36003 or not right and let's say I'm just
6:40:38going to clear this and And you'll have
6:40:40to run it once again and you will see
6:40:41that we don't have any row. But the
6:40:43moment I'm going to execute this one
6:40:45here once again. Let's I'm just going to
6:40:47change this one to 003 and let's do this
6:40:50on a laptop stand 03 and rest all let's
6:40:53keep it same and you'll see that what
6:40:55will happen right? It's going to do two
6:40:56things. First it's going to execute this
6:40:58and at the same time it will it will be
6:41:00giving me the updated data with this
6:41:03particular skew. So let's say now I'm
6:41:05just going to run it one second. Okay.
6:41:08Why you getting zero rows? We have to
6:41:11save this. See this kind of mistake I'll
6:41:13do. We have to save this file and let's
6:41:15run once again. And you can see that you
6:41:17are getting one data. And this is the
6:41:19skew just we have created. Okay. So this
6:41:21will be inserting a single row. Now
6:41:23inserting multiple rows. Now multiple
6:41:25rows are again very very simple but
6:41:27still I wanted to show one interesting
6:41:29thing that how you can query multiple
6:41:31data when you're going to add multiple
6:41:33uh how you're going to query multiple
6:41:36data from DV when you're going to insert
6:41:38multiple data into DV. Okay. So here
6:41:40let's do one thing. I'm just going to do
6:41:4203 and I'll do insert
6:41:45multiple
6:41:47rows dosql.
6:41:50Again this will be the same thing. So
6:41:52you have to do insert into products
6:41:57and here I'm just going to do this one
6:41:58as name category
6:42:01price stock
6:42:04then you have skew and then you have
6:42:06description correct and then I'm just
6:42:08going to take values
6:42:11and here what I will do right I'm going
6:42:13to add multiple here okay so let's I'm
6:42:15just going to do laptop stand five let's
6:42:18give this one as electronics
6:42:22Let's give some data. Let's give this
6:42:24one anything. And here I'm just going to
6:42:26do electronic
6:42:28laptop
6:42:30100. Something like this. And then I'm
6:42:33just going to do laptop
6:42:37stand 5
6:42:40desk. So give comma copy this. And then
6:42:45I'm just going to paste it here. This
6:42:47will be laptop.
6:42:52So copy once again and then I'm just
6:42:54going to paste it three times. And let's
6:42:56do this one as 006. Then I'm just
6:42:58[snorts] going to do 101 and this will
6:43:01be laptop 6. Let's do this one as laptop
6:43:047. And change this one 102. And I'm just
6:43:06going to do seven. Okay, I'm just
6:43:08keeping all the same which is fine. And
6:43:10then I'm just going to close this. And
6:43:11now what I'm going to do right, this is
6:43:13going to insert all these three data.
6:43:15Now I wanted to check all these data
6:43:17that I have added just now multiple
6:43:19data. So how you can do that right? So
6:43:21you do select let's see I'm just going
6:43:23to take name I need category I need
6:43:25price I need stock and also I need skew.
6:43:30Now what you need to do you have to
6:43:31always give the uh from destination from
6:43:34where and now I wanted to give okay
6:43:36where skew. Now we have to give in.
6:43:40Okay. So in is going to give give you
6:43:42the or allow you to add multiple
6:43:46points that you wanted to query. For
6:43:47example, I wanted to check whe the skew
6:43:50is this. So you can add it here. Then
6:43:53you have to give comma. And then you
6:43:54wanted to check this data also.
6:43:57And then you also wanted to give this
6:43:59102 also. So what this is going to do?
6:44:02So this is going to insert all these
6:44:04three. And at the same time this is
6:44:05going to give you the information back.
6:44:07Right? So let's see if this is working
6:44:08or not. So I'm going to close this,
6:44:11clear this, run this here. So copy this
6:44:20and then I'm going to paste it here and
6:44:22you can see that you are getting all
6:44:23three. So you're getting only name,
6:44:24category, price and skew. And here
6:44:27you're getting all three. Now these
6:44:28three are the newly data. How this is
6:44:30giving? This is giving the based on skew
6:44:32because skew is unique here. Okay. So
6:44:34this is the concept of inserting single
6:44:37row query, inserting multiple rows and
6:44:40how you can query. So with this now
6:44:41let's move on to the next one. All
6:44:43right. So moving to the next one. So
6:44:44let's create one more file and I'm just
6:44:46going to give this one as select
6:44:50specific
6:44:53columns
6:44:54versus select start that we have already
6:44:57done right. So I'm just going to do
6:44:58versus select
6:45:01stars.
6:45:02Select stars SQL. Okay. So what I mean
6:45:06by this? So first of all, what is select
6:45:08star? Select stars is going to return
6:45:11every column for every product. As
6:45:13simple as that, right? Uh now if you're
6:45:16a beginner, I think we have already
6:45:17covered select star from this select
6:45:19star from this particular destination.
6:45:21And that is very easy. But when your
6:45:24application will grow, let's say you're
6:45:26creating actual production level
6:45:27application, what actually you should
6:45:29do, right? Or maybe there can be some
6:45:31specific scenarios where you only want
6:45:34to use specific columns or you want to
6:45:36get specific columns not you want to
6:45:38return each and every column. Consider
6:45:40it's possible 100% possible that there
6:45:42is a particular table that has 100
6:45:45columns. I'm just giving example okay
6:45:47and you don't want to return all the 100
6:45:49columns every time. So this is where we
6:45:52have something called select specific
6:45:54columns concept. Okay. So how we are
6:45:56going to do do that? So first of all I'm
6:45:58just going to write comment here that
6:46:01okay select star is going to return
6:46:02every column. So it returns every
6:46:05columns and then we have something
6:46:07called select specific columns. So if
6:46:10select specific columns
6:46:13is going to return is going to return
6:46:17the columns that I want that I want.
6:46:22So first of all we have select.
6:46:26So I'll do star from and then I'm just
6:46:29going to do this one as products right?
6:46:31So this is going to give me every single
6:46:33information or every single products
6:46:35that I have. So if I save this now let's
6:46:38run it first we'll do one by one and
6:46:40let's
6:46:42copy this
6:46:47paste it here and then if I enter so
6:46:49it's going to give me employee product
6:46:50okay whatever that we have added here
6:46:53that's fine now what I need to do right
6:46:56I only want to get certain columns only
6:46:59although this part we've already covered
6:47:01so I'm just going to comment it out
6:47:02let's do select so I only want to get
6:47:05name I only want to get category. I only
6:47:08want to get price and I only want to get
6:47:11the stock of this part individual
6:47:14product. And then you just have to do
6:47:16from and then you're going to give
6:47:18product. So this is going to give you
6:47:20only the four columns that you need. As
6:47:23simple as that, right? So again run it
6:47:25and you can see that you're going to get
6:47:26only four columns and it's very very
6:47:28clean, right? You can see that. Now for
6:47:30example that can be s possibility that
6:47:32you only want price column. So you just
6:47:35have to pass price here, right? So for
6:47:37example, let's say you only want price.
6:47:43Okay. So save this and let's clear this
6:47:46and run it once again. And you're only
6:47:48going to get price. Makes sense, right?
6:47:51So this is how you have to select
6:47:53specific columns. Now what I need to do,
6:47:55right, you can also add allis. Now allis
6:47:58actually are very useful and you'll see
6:48:00that in many applications developers
6:48:03will use allis. So allis is going to do
6:48:05this right. So allis is going to help
6:48:08you to understand the output column name
6:48:10much better way. So okay. So I'm just
6:48:12going to do allis creates.
6:48:15No I'm just going to do as so this is we
6:48:18have something called as this is sort
6:48:21this is in sort as allis. So I'm just
6:48:23going to do as creates and allis.
6:48:29Okay. for the output
6:48:35output of that column name. Output of
6:48:38that
6:48:40column
6:48:42name, right? And what is the advantage?
6:48:45No, definitely allis will be makes the
6:48:48column name
6:48:51easier to read. How we can do that?
6:48:55Simply we are going to do select and
6:48:57let's say I wanted to get name but I
6:48:59wanted to get this name column as
6:49:03you can give any name you want product
6:49:05name. So now I'll be able to now you
6:49:07might counter me okay when we have
6:49:09created this table we can definitely
6:49:11give this one as product name absolutely
6:49:12yes you can you can do that but there
6:49:14can be situation where actually want to
6:49:16use this as a license okay that can be
6:49:18so many situation can occur now let's
6:49:20say want to give here price I want to
6:49:22get the price but I wanted to get the
6:49:24price as my selling price okay or I
6:49:28wanted to get my stock and stock will be
6:49:30my how my how many available quantity
6:49:33quantities are there so I'll do
6:49:34available quantity and then always you
6:49:37have to give your destination. So you
6:49:39have to give from products. So if I save
6:49:41this also let's comment it off here.
6:49:44Save this one and see that what will
6:49:46happen. You're going to get the exact
6:49:47details or syntax error as something we
6:49:50have done. Maybe I haven't given comma.
6:49:52See so I have to give comma here. So
6:49:55save this and then if I clear this let's
6:49:59run it once again. So you're going to
6:50:00get no product name. This column name is
6:50:02not changed. This is a selling price and
6:50:04this is your available quantity and
6:50:05you're going to get as many details
6:50:07sorry as many columns you have that is
6:50:10that stays same only thing is your
6:50:13column name allis now change to the name
6:50:15that you want okay so this will be the
6:50:17concept of your select specific columns
6:50:20that you have already discussed here and
6:50:22then also how you can how you can use
6:50:23allis so with this now let's move on to
6:50:25the next one so next one maybe what we
6:50:27can do here I think where we have
6:50:29already discussed right where means I'm
6:50:31talking about this on this so where is
6:50:33actually we usually use for our basic
6:50:36filtering but still let's uh do one more
6:50:38time so that we will understand this one
6:50:40much better way so I'm just going to do
6:50:42this one as well basic filter
6:50:46dosql okay so first of all let's say I
6:50:49wanted to get couple of things that I
6:50:51wanted to get the products from one
6:50:53particular category and now why this is
6:50:55helpful let's say you're creating
6:50:56e-commerce website and you want to have
6:50:58a API call where these will be products
6:51:01and let's say you have category and this
6:51:03category will be electronics. You're
6:51:05getting what I mean. So I only wanted to
6:51:07get all the categories of this
6:51:08electronics, right? So all electronics
6:51:10category products. This is where your
6:51:13where filter is very very helpful. Okay.
6:51:16Now what actually where helps where
6:51:19helps? So this is going to reduce the
6:51:21rows returned by a particular query. Now
6:51:23let's how I'm going to do this. Now you
6:51:25have to try to do this all by your own.
6:51:28For example, let's say I wanted to get
6:51:29select. I wanted to get the name. name I
6:51:31wanted to get the category I wanted to
6:51:33get the price
6:51:35and I wanted to get from products
6:51:37definitely this is the table but now I'm
6:51:39just going to give okay where the
6:51:41category should be equal to electronics
6:51:45so you don't want all these uh products
6:51:50only one products where the category is
6:51:52electronics and this is going to give
6:51:53you all the electronics products so
6:51:55let's copy this the name and let's run
6:51:58it here.
6:52:01Okay. So now you can see you're getting
6:52:03name, category and these all are your
6:52:04electronics products. You make also
6:52:07confirm this just uh if I go here let's
6:52:10say you have furniture you can see the
6:52:11office chair and you can see this office
6:52:13chair is not coming here. Okay. So that
6:52:16means this is working. Now I'm going to
6:52:18give you some of the homework or maybe
6:52:20I'm going to do here also but try to do
6:52:21by yourself that you have to give uh you
6:52:24have to find some products
6:52:26where the price is greater than 1,000
6:52:31and it's very very simple. So what you
6:52:33can do you can again do select I want to
6:52:35get the name of the product I wanted to
6:52:37get the price of the product I want to
6:52:39get from my products table but I wanted
6:52:41to give a basic filter that where the
6:52:44product price has to be what greater
6:52:46than 1,000 that's it and if you run this
6:52:49you're going to get result and you'll
6:52:52see that you're going to get where the
6:52:53price is greater than 1,000. So this is
6:52:56another situation right and the same way
6:52:58you can do other also. Now let's say you
6:53:01only wanted to get where the is active
6:53:04is false. Correct? So let's see if we
6:53:06have an is active false or not. So we
6:53:09have two true true we have one false
6:53:11item. Okay fine. Then so let's say I'm
6:53:14just going to comment it out that I'll
6:53:16give that find products which are not
6:53:22active. So here I'm just going to do a
6:53:24select give name give me is_active
6:53:30from products and here you have to give
6:53:33what you have to give where e is active
6:53:35will be what equal to false right and
6:53:38this is going to give you where it is
6:53:40false and just run it here
6:53:46now it see all monitor and this is the
6:53:50product so this is how you can make use
6:53:53of your where filter. So I think this
6:53:56should be more than enough. Now moving
6:53:57to the next one. Next let's understand
6:54:00one more. So I'm just going to do 06 and
6:54:02let's give this one as and or not. These
6:54:06all are very important. Okay. These all
6:54:08are also filters all three. So let's
6:54:11close everything else. Okay. First one
6:54:14what is and I think this is universal
6:54:18concept right? Hands mean every
6:54:21condition
6:54:23must be true. Right? Then you have or at
6:54:29least
6:54:34one condition
6:54:37must be true.
6:54:39And then you have not. So not will be
6:54:42your reverse condition, right? Reverse
6:54:44or exclude. I'm going to say a
6:54:47condition. So let's say how this will
6:54:50work. Now let's say I wanted to make a
6:54:53filter or I wanted to create a filter
6:54:55which is going to return me electronics
6:54:57product. Okay. But if the price is
6:55:00greater than 100. So I I'm going to
6:55:03repeat once again that give me the
6:55:04products
6:55:06where it is electronics product. It is
6:55:09electronics
6:55:12electronics
6:55:14product but the price has to be greater
6:55:17than 1,000. So this is the query that I
6:55:20need to write. So how I can do that?
6:55:22Here you have a and condition. Why?
6:55:25Because both these condition has to be
6:55:27true. It has to be electronics and at
6:55:29the same time it has to be price has to
6:55:31be greater than 1,000. Makes sense,
6:55:32right? So that means if I try to do here
6:55:34select
6:55:36give me name give me category
6:55:42price from
6:55:45products.
6:55:46Now I have to give
6:55:49where the category is equal to
6:55:53electronics.
6:55:56And now I have to give here and filter.
6:55:59Okay. So I'm just going to do and let's
6:56:02do this one as price has to be greater
6:56:05than 1,000. Okay. So this is going to
6:56:07give you all the data that satisfy this
6:56:09condition. Now let's go one by one I
6:56:11think. Right. So we have electronics.
6:56:13Electronics electronics. So this USBC
6:56:15cable this should not come here. Why?
6:56:17Because this is electronics but this is
6:56:19less than 1,000. So let's see what is
6:56:21happening here. So I'm just going to
6:56:22save this. Go up. Let's clear this.
6:56:28Copy this. And then I'm just going to
6:56:31paste it here. And let's say how many
6:56:33data we are getting. All right. So you
6:56:35can see that you are getting five rows.
6:56:37Now if I just do this one as let's do
6:56:39this one as 100. And you'll see that
6:56:42this will increase for sure because now
6:56:44the condition is separate. Right? So I'm
6:56:46just going to run here. So you're
6:56:47getting six rows. So USB C cable this is
6:56:50also coming right. So this is the
6:56:52concept of and filter. Now what how you
6:56:56can use odd filter. Now see these things
6:56:58are not that much difficult to
6:57:00understand right you can do only once I
6:57:02can guarantee you'll be able to apply in
6:57:04a real project also and that is the
6:57:06reason you'll think that why these kind
6:57:07of videos are very important like if
6:57:09you're watching this video you can watch
6:57:11any kind of complicated project videos
6:57:13but if your basics are clear right you
6:57:15don't have to watch those videos also
6:57:17you'll be able to create project by
6:57:18yourself for example let's say you don't
6:57:20know the concept of where and and
6:57:22posgrsql and you started a AI project on
6:57:25YouTube uh that using posgress skill you
6:57:28can do that but learning concepts are
6:57:30very much important and how you going to
6:57:31apply [clears throat] those concept in a
6:57:33real project that is the main skill so
6:57:36now here I'm just going to commit it out
6:57:37now let's give one more filter here that
6:57:40uh what I'm going to do like maybe let's
6:57:42do that you have to give me products
6:57:45right where
6:57:48category is electronics
6:57:51electronics and let's see what else we
6:57:53have we have electronics and let's do
6:57:55furniture both Sorry uh category is
6:57:58electronics or this can be furniture
6:58:01right so give me the products where the
6:58:03category is electronics or it can be
6:58:05furniture it can be either so now I'm
6:58:08just going to do select so I'll give
6:58:10name category price and I'm just going
6:58:14to give from the destination products
6:58:17now what you'll do so where the category
6:58:20has to be either it is electronics
6:58:24and now we have to give a or condition
6:58:26here Right. So I'm just going to do this
6:58:27can be or.
6:58:30So or category can be furniture also.
6:58:34Okay. That's it. So now this is a or
6:58:38condition.
6:58:39So now let's run it once again.
6:58:43So we're getting both electronics and
6:58:45furniture. Fantastic. So this is about
6:58:47the and and or. Now let's understand
6:58:51some not condition, right? Not is going
6:58:53to exclude a particular condition. So
6:58:55now maybe let's do one thing that I
6:58:57wanted to return some products that are
6:59:00not in a maybe let's say stationary
6:59:02category something like that. So let's
6:59:04say how many categories we have. We have
6:59:05a stationary category here. You can see
6:59:07two products are there. So what I'm
6:59:09trying to do here that I wanted to get
6:59:11all the products where it is not
6:59:13stationary right so it's exclude
6:59:16condition. So here let's I'm just going
6:59:18to do okay give me name also give me
6:59:20only category. So we using selective fil
6:59:23uh column logic here that we have
6:59:24discussed here select specific columns
6:59:27also if you notice one thing that every
6:59:29time we are going forward with different
6:59:31concept we are trying to apply the
6:59:33previous concept that we have learned
6:59:35for example we have just now we have
6:59:37learned select specific columns and you
6:59:38can see that we are applying that
6:59:39concept this is the learning that I
6:59:41always mentioned in all my other videos
6:59:43that when you're learning incrementally
6:59:45right or gradually every time you're
6:59:47going to learn a new concept see if any
6:59:49of the concept from the previous thing
6:59:50you can apply there or not. That is the
6:59:52real learning that you can do. Okay. So
6:59:55here this will be select name and
6:59:56category. So I'm just going to do from
6:59:58products. And here what we need to do we
7:00:00have to do where and then I'm just going
7:00:03to do what not. Okay. So this is negate.
7:00:05It's a exclude condition and I'm just
7:00:07going to do category is equal to. So
7:00:09let's say maybe let's do furniture only.
7:00:11So I'm simply telling that where the
7:00:14category is not furniture you have to
7:00:15return me those products. So now let's
7:00:17run this again and you can see that you
7:00:19getting electronics stationary but
7:00:21you're not getting furniture. If you
7:00:23change this one to stationary you'll see
7:00:25that you're going to get now you're not
7:00:28going to get stationary here. Okay
7:00:34see you're getting category and
7:00:35furniture.
7:00:36So this will be your not condition. Now
7:00:40maybe let's do one more right. So let's
7:00:42do little complex that what you can do
7:00:45right you can also use parenthesis okay
7:00:47now for example let's say I want to do
7:00:49something like this I wanted to write
7:00:50one query let's see if you're able to
7:00:52understand or not so I'm just going to
7:00:53take the I'm going to get name I wanted
7:00:55to get category I also wanted to get
7:00:58price I also wanted to get uh stock also
7:01:01this time from I think this you know
7:01:03from products now I wanted to do right
7:01:06so give me where now I have to give a
7:01:08parenthesis parenthesis is nothing but
7:01:11it's going to If you're writing a
7:01:12complex logic, it is much much easier to
7:01:15understand and it is also safe. So here
7:01:17I'm just going to give okay category is
7:01:20equal to electronics
7:01:23and here I'm just going to or this can
7:01:25be so I'm just going to do category can
7:01:27be also furniture.
7:01:31Okay. And then I'm going to give another
7:01:33and condition here. So I'm just going to
7:01:34do okay and and let's give stock has to
7:01:38be greater than zero. That's it. Okay.
7:01:40So this is another we can apply here. So
7:01:44if I run this once again
7:01:47and you can see that you're going to get
7:01:49all this right. So you're going to get
7:01:50either it is electronics or it is
7:01:52furniture but the stock is greater than
7:01:55zero. Okay. Now I think this is done.
7:01:58What else? So maybe I think this
7:02:02uh I'm thinking to write one more. No, I
7:02:05think this should be enough or let's
7:02:06write one more here. So I'm just going
7:02:08to give one real world example. Okay. So
7:02:10let's do select let's do name price
7:02:14stock and I'll do e is active. Now I
7:02:17wanted to give is active also. So I
7:02:19wanted to give from products
7:02:21and now I'm just going to do where is
7:02:24active should be equal to true right? So
7:02:27it will be true and at the same time so
7:02:29I'm just going to do and the price is
7:02:33less than 1,000 or the stock can be
7:02:38greater than or equal to 100. See I just
7:02:40wanted to explain what you know by
7:02:42writing all this that you can do
7:02:43anything any combination you have to
7:02:45understand the concept. So first you
7:02:46tell me that you give me all the active
7:02:48products where the price can be less
7:02:50than 1,000 or stock has to be greater
7:02:53than or equal to 100. So this is also
7:02:56going to give you the result here. So
7:02:57let's see if I run once again
7:03:00and you can see that what you're
7:03:01getting. You notice in all here stock is
7:03:05actually greater than 100 and also it is
7:03:08less than 100. Why? Because you're using
7:03:10a or condition here the price is
7:03:13actually 100. So it's actually
7:03:14satisfying this condition. Price has to
7:03:17be less than 1,000. Okay. So that is the
7:03:19reason you're getting this particular
7:03:20combination. But what you need to see
7:03:22you have to see that this is active is
7:03:24actually true for all. Okay. So this is
7:03:27how you can make use of this and or and
7:03:30not filter. So with this now let's move
7:03:32on to the next one. Okay. So let's move
7:03:33on to the next one. Okay. So I'm just
7:03:35going to create one more file and let's
7:03:36give this one name as like I like and
7:03:41also let's give this one as patterns.
7:03:44SQL. Okay. So let's understand these
7:03:48some of the uh pattern matching that we
7:03:50can use. These are also very very
7:03:52important. So one we have like
7:03:56okay so this like is nothing but this
7:03:59will be case sensitive pattern match.
7:04:04Okay. Then you have something called I
7:04:06like. Okay. This will be case
7:04:08insensitive
7:04:11pattern
7:04:12match. Okay. Then you have something
7:04:15called I don't know how to say I think
7:04:18percentile I think this will be
7:04:20percentile only percentile means this
7:04:22will be I think any number of characters
7:04:26yes so this will be any number of cars
7:04:28okay or characters whatever you want to
7:04:29write and then you have uh we also have
7:04:32this I think underscore sorry uh this
7:04:35underscore this underscore will be means
7:04:38exactly one character so this will be
7:04:40exactly one character okay so let's see
7:04:42so first I wanted to do something like
7:04:45this. Okay, let me go here and I'll see
7:04:47that I have this wireless uh product.
7:04:50Okay, so I wanted to find some product
7:04:53where the name will start with wireless.
7:04:56Okay, so let's how we are going to do
7:04:58that and then I'm going to explain. So
7:04:59I'm just going to do here select and
7:05:01wanted to get name and price both and
7:05:04then first of all we need to do from
7:05:06products
7:05:08and now I will give that where the name
7:05:13like okay so the name like so here I'm
7:05:15using a pattern and I wanted to give
7:05:18here that this will be wireless okay and
7:05:20when I'm going to give this right here
7:05:24so this means so this after means
7:05:28anything can uh anything can come after
7:05:30it. Okay, this percentile after wireless
7:05:34means this percentile we have right. So
7:05:35this is after wireless text. So this
7:05:38means anything can come after that.
7:05:41Okay, I'm I will just write it here. So
7:05:44the percentile
7:05:46percentage whatever after wireless
7:05:50means
7:05:53anything can come after it. Okay. So
7:05:58let's see how this is happening. So save
7:05:59this and I'll go here. Let's clear this.
7:06:02We'll do one by one and then I'm just
7:06:04going to rename copy this.
7:06:08Let's remove this.
7:06:13Okay. So here you can see that what you
7:06:15are getting. Okay. Something we getting
7:06:17syntax is there. Okay. Got it.
7:06:21To give this Oh, we we have to remove
7:06:24this. I've given in the wrong place. So
7:06:26let's run once again. Clear.
7:06:30Okay. See. So now you're getting
7:06:32wireless mouse and it makes sense,
7:06:33right? Because we have only one product.
7:06:36All right. Now what this line you
7:06:38understand that this anything can come
7:06:40after it. So this is what I'm talking
7:06:41about. So anything can come after
7:06:43wireless. But this is going to do that
7:06:45matching. Okay. Next. Let's do one more
7:06:48example that. Okay. Let's see how many
7:06:51products we have. Uh what else? Maybe
7:06:53let's do something with this desk. Okay.
7:06:56So I wanted to find some product where
7:06:58the name contents desk. Now what this I
7:07:02like is going to do as I already
7:07:04mentioned is this is a case insensitive
7:07:06means it's usually going to ignore any
7:07:09kind of upper case or lower case
7:07:10differences. So what I mean by this what
7:07:13is like how we understand that this is
7:07:16going to ignore. So for example let's
7:07:17say this is going to match with desk.
7:07:21This is also going to match with desk.
7:07:23So you can see that this is capital this
7:07:25is small and this is also going to match
7:07:28with disk you're getting right. So this
7:07:30is what we are talking about case
7:07:32insensitive. So let's have this is
7:07:33happening. So I'm just going to do name.
7:07:35Let's also take category now and I'm
7:07:37also going to do price and here I'm just
7:07:40going to do again from products. And now
7:07:42I'm just going to do where name now you
7:07:45have to do I like. Okay very very
7:07:47important. And you just have to give
7:07:49this will be desk.
7:07:51Okay. So this is going to do this
7:07:53particular match. So now let's save this
7:07:56and run once again and we'll see what is
7:07:58happening here.
7:08:02Okay. So you're getting a standing desk
7:08:04and I think we have only one. So this is
7:08:06the standing desk. Okay. So we have
7:08:08learned these two I like. Sorry like and
7:08:10I like. Okay. So let's write one more
7:08:12here. So maybe uh you can do right. So
7:08:15you can also search across multiple
7:08:17columns. So for example, let's say let's
7:08:19go here and maybe we'll take this
7:08:22example. Okay, let me just check. Okay,
7:08:24so this is good. So we have chair in
7:08:26this name also and let's see have chair
7:08:28in this description also. So you can
7:08:30check in both the columns. Okay, so for
7:08:32example, let me just comment it out
7:08:34here. This one and also this one.
7:08:38So we'll just do select. Let's do name
7:08:41category
7:08:43and also I'm just going to take the
7:08:44description also. Okay. And here I'm
7:08:47just going to do from and I'll do
7:08:49products. And now first of all I will do
7:08:52where the name. So here I'm just going
7:08:55to do I like and I'm just going to give
7:08:57this one as so I wanted to take chair
7:08:59right. So I'll do chair. And then what
7:09:02you can do right you can give a or.
7:09:04Okay. Now this one we have already
7:09:06discussed in the previous part. So you
7:09:07or the description I like and then you
7:09:11have to give the pattern that you wanted
7:09:12to match. For example I wanted to check
7:09:14the chair word only. So this is how you
7:09:16need to check with multiple columns.
7:09:18Okay. So let's save this and we'll
7:09:21[clears throat] go let's run this
7:09:24and you can see that you're getting
7:09:25office chair and this is also
7:09:27comfortable chair. So this both you
7:09:29have. So this is how you can make use of
7:09:31like I like and percentile. Okay. So now
7:09:35maybe let's move on to the next one.
7:09:37What what else we have? Let me think.
7:09:39Okay. We also do in not I think in we
7:09:42have already covered in some uh previous
7:09:44uh parts but still let's do it. So I'm
7:09:46just going to create one more. So I'm
7:09:47just going to do 08.
7:09:50So let's do here. Let's give in. We also
7:09:52have to not and also sorry we have in
7:09:56not in and between this. So we'll do in
7:09:59not in and also let's do between this
7:10:01also important between also we have to
7:10:04understand. Okay. So first let's start
7:10:06with in. So in will be in simple way
7:10:10value that value you want to check that
7:10:13must match one item from the list.
7:10:15Simple. So here value must match one
7:10:20item from the list. So this will be in.
7:10:24Next you have not in. So what actually
7:10:27not in? So this will be value must not
7:10:30match. By the name only you can
7:10:31understand right? So this will be value
7:10:33must not match any item from the list
7:10:39and then you have something called
7:10:41between. Okay, this is also important.
7:10:43So between will be value must be inside
7:10:46particular range because from the name
7:10:47only you can understand. So this will be
7:10:49value must be between or I'm just going
7:10:52to write in a better way. This will be
7:10:54inside a range. Okay. So now let's say
7:10:57what we are going to do right. So in the
7:10:59previously we have done what that we are
7:11:01checking right that if the category is
7:11:03electronics or the category is furniture
7:11:06here we can use in instead of doing that
7:11:08how so now let's I'm just going to do
7:11:10select name give me category and also
7:11:13give me the price from products right
7:11:17now what I'm going to do right I'm going
7:11:18to check where the category in so
7:11:20previously we have done okay category is
7:11:22equal to this or category equal to that
7:11:24like that but here I'm just going to do
7:11:26give me in so that means these value
7:11:28must be one of that value that I wanted
7:11:30to check. So value can be either
7:11:32electronics or the value can be either
7:11:35furniture.
7:11:38I hope this is clear. This is not that
7:11:39much difficult to understand. Simple.
7:11:41Okay. So this is where you can use this
7:11:43in.
7:11:45So clear this and let's run it here.
7:11:51Okay.
7:11:54Right. So you're getting electronics and
7:11:56furniture stationary. you are not
7:11:58getting. Okay. So now you can also
7:12:01double check this one. Maybe let's say I
7:12:02wanted to check this stationary and I
7:12:04wanted to remove this electronics,
7:12:05right? Save this and you are only going
7:12:08to get now stationary and furniture. So
7:12:10you're getting furniture and stationary.
7:12:12All right. So this will be in. Very easy
7:12:15to understand. Next uh what else we
7:12:17have? We have not in. Not in is again
7:12:19it's going to exclude multiple values.
7:12:21Means I wanted to return all the
7:12:24products that are not electronics, not
7:12:26furniture. So that means what if it is
7:12:28not electronics not furniture means it
7:12:30is only going to give me stationary
7:12:31products. So how we can do that? So do
7:12:33name category from products. And now you
7:12:37have to give me where the category
7:12:41not in. Okay. And then you're going to
7:12:43give okay you want to check that okay
7:12:45this has not be has uh has to be only
7:12:48stationary. I'm talking opposite. So it
7:12:50has to be only stationary. It don't have
7:12:53to be electronics and also it should not
7:12:55be furniture. So we excluding both. And
7:12:59here the part is important that is not
7:13:01in. And if you run this, so you're only
7:13:03going to get the stationary product,
7:13:06right? See, so you're getting only
7:13:07stationary product. Simple. So this is
7:13:10about the not in. What else we have? We
7:13:12also have the between
7:13:14how we can check. Now let's say I wanted
7:13:16to check on the price that give me all
7:13:18the products where the price is between
7:13:20100 to 2,000 something like that. So it
7:13:23will be in that bit range right. So in
7:13:25that case we can check that. So now here
7:13:27you can also use and that if it is
7:13:29greater than 100 less than this like
7:13:31that but this uh this in not in between
7:13:34are very very very useful once you start
7:13:36using all of these. So I'm just going to
7:13:38do this one as price. I'll do from
7:13:42products. And what you have to give? You
7:13:44have to give where you want to check the
7:13:45property. So I have to check the price
7:13:47property. And this will be between. And
7:13:49now you have to give okay 100 and see we
7:13:52using and and 2,00.
7:13:55So it will give me in that range only.
7:13:59So now
7:14:01also it this is also important. This is
7:14:03going to include 10 and 2,000 if I'm not
7:14:06wrong. So let me just quickly check. So
7:14:08include means it's not like from 101 and
7:14:111 9. It is also going to add 100 and
7:14:142,000 also. So let me just check that.
7:14:17Will this
7:14:19include 100 and 2,000 also. I think yes.
7:14:25Just confirm.
7:14:31Okay. Right. So this is see it is like
7:14:34where right? It is similar to where
7:14:36price is greater than equal to 100 and
7:14:38price is less than or equal to 2,000. So
7:14:40that means this is also going to add
7:14:42sorry this is going to keep 100 and
7:14:432,000 also. Makes sense right? So now if
7:14:45you run this you can see that you're
7:14:46getting 100 see all three two uh three 9
7:14:49and 1 2 9. So it will be in that range
7:14:51but again I'm repeating this is also
7:14:53going to include 100 and 2,000
7:14:55important. So I think this is done. Next
7:14:58let's comment it out. What else is left?
7:15:02Uh
7:15:04I think we have covered all three right
7:15:06now we can let's do one more
7:15:07combination. So let's say I'm just going
7:15:09to get name category price and stock
7:15:14from products.
7:15:17Now I'm just going to do where the
7:15:18category in. So give me electronics
7:15:24and maybe let's say stationary product.
7:15:30And then I'm also going to do here and
7:15:33price between 100 and 1,500 or whatever
7:15:38you wanted to give 149 something like
7:15:40that you're getting how we are combining
7:15:43all of these all the concept that we are
7:15:44learning so far [snorts] and if you run
7:15:46this so clear this and run it here
7:15:49you're going to get all this result here
7:15:50okay so this is how you have to do it in
7:15:53stationary I think we don't have let's
7:15:54see if stationary if it is 101,499
7:15:58so this is 99 in stationary. So if I
7:16:01make this one to 10, so it should give
7:16:03me stationary also if I'm not wrong. So
7:16:06clear this and run once again. Now
7:16:08you're getting stationary also because
7:16:09both are less than 100. Okay. So this is
7:16:12about in, not in and between. All three
7:16:15that you have learned so far in this
7:16:17particular file are actually very
7:16:18important. So now what else we have? We
7:16:20also have something called null
7:16:23filtering. And I think we have already
7:16:25covered that null and not null. But
7:16:26still it is important. So let's do let's
7:16:29not skip this. So I'm just going to do
7:16:31this one as null. Let's do and uh what
7:16:34I'll do is not null something like this
7:16:36is not nullsql.
7:16:40So here first of all null filtering
7:16:42means again null means very important
7:16:44means missing value or unknown value
7:16:47something like this.
7:16:50Okay. So here what we need to understand
7:16:55right that when you're going to check
7:16:57you should not check with null you
7:16:59should not check null using equal to
7:17:01null so what I'm talking about that you
7:17:03should not you should not check null
7:17:09using equal to null you should not do
7:17:11that so correct is what we need to do
7:17:13either we need to check is null or we
7:17:16have to check is not null okay so this
7:17:19is the important part here. Now let's
7:17:21say [snorts]
7:17:22here what we need to check that I wanted
7:17:24to get all the products but the
7:17:25description is missing. I'm just giving
7:17:27example. Okay. Now here we have to see
7:17:30that this doesn't mean the empty string
7:17:33that mean that no value is present for
7:17:35that particular description property. So
7:17:38here so I'll do select let's say select
7:17:40name comma description
7:17:44from products
7:17:47and here I'm just going to do where the
7:17:50description
7:17:51is null okay so simply telling the
7:17:54description is not present so let's run
7:17:56this okay so clear this and I'm just
7:17:59going to copy here and let's run it
7:18:03here.
7:18:07Okay. So you can see that USBC cable and
7:18:10jail pen. So let's see what is happening
7:18:11here. So you can see that we have null
7:18:12here. Okay. And for this also we have
7:18:15null here. So you're directly checking
7:18:17that if this is equal to null. Correct.
7:18:20Now you want to check that where the
7:18:22description is available. So how you're
7:18:24going to do that is not null. Okay. So
7:18:26here you copy this and then you're going
7:18:29to do is not null. That's it. So this is
7:18:33the difference and if you now run this
7:18:35so you're going to get all the products
7:18:36where the description is available.
7:18:38Okay. So we need to understand again I'm
7:18:40repeating this thing that null means
7:18:43missing value or unknown value. But when
7:18:45you're going to check null using equal
7:18:47to null you can't check. You should
7:18:49check with is null or is not null. Now
7:18:52let's see a practical example right
7:18:53practical back end example. Let's say
7:18:55you're creating admin dashboard where
7:18:56admin wanted to check something like
7:18:58that. Okay me [snorts] all the active
7:19:00products right? These products are
7:19:01active that means user can see the
7:19:03active products from the e-commerce
7:19:05website. But for this particular product
7:19:07the description is missing. So admin
7:19:09admin needs to query this. So how we we
7:19:12can do that? So I'm just going to do
7:19:13okay give me name give me the category
7:19:15of this product. Give me is active
7:19:19and also let's say give me description
7:19:21also. So from products
7:19:25where
7:19:26is active is equal to what? True. And
7:19:29here you have to give and
7:19:31description is null.
7:19:34That's it. So this is going to give you
7:19:36all the active products but at the same
7:19:38time the description is missing. So
7:19:40let's see if we have so this product
7:19:42both are active. So you can see that
7:19:43both are active but description is null.
7:19:45So this is how you can make use of null
7:19:48and is not null. Okay. So with this I
7:19:51think we have covered most of the
7:19:53things. Now still we have lot of things
7:19:54to cover in this one. So what are the
7:19:56things still we need to cover? We need
7:19:57to cover order by limit offset all these
7:20:00things how we can update right we
7:20:02haven't started update yet that how we
7:20:03are going to update a single row how you
7:20:05can update multiple rows how you can
7:20:07delete rows and also the concept of
7:20:09returning so all these things we're
7:20:11going to understand in the next part all
7:20:12right so let's move on to the next one
7:20:14which will be so let's understand order
7:20:15by
7:20:19now this is one of the most used uh
7:20:23concept that you're going to use because
7:20:25in projects sorting
7:20:27that you're going to use is everywhere,
7:20:29right? Almost in every functionality or
7:20:31most of the functionality I will say you
7:20:33have to do some kind of sorting right so
7:20:35here uh so let's understand so maybe
7:20:37let's say let's do this one practically
7:20:39that we wanted to sort our products from
7:20:42cheapest to expensive right so that
7:20:45means it will be in ascending order now
7:20:47these are very simple concepts I'm just
7:20:49going to do select and give me name and
7:20:51the price of the product from my
7:20:54products collection and you just have to
7:20:57use order Y okay and then you have to
7:21:00give the property and I wanted to do
7:21:03what I wanted to sort based on this
7:21:05price property right so and also what
7:21:07kind of sort you wanted to do that also
7:21:09we need to give so I wanted to give
7:21:11ascending order so this will be my query
7:21:13very very simple and if I just run this
7:21:15and we'll see that this is going to give
7:21:17me the name and the price in ascending
7:21:19order so let's run this
7:21:23okay and you can see that this is
7:21:25working fine so from 25 to 15,990 29.
7:21:29All right. So I think this is done. The
7:21:31same thing you can do for descending
7:21:33order also. So I'm just going to do
7:21:35exact same. So I'll copy this, paste it
7:21:38here. And this will be descending order.
7:21:41Okay. Nothing else. So it will be from
7:21:43expensive to cheapest. So do clear. And
7:21:47now this will be opposite. That's it.
7:21:49Nothing much to discuss here. Then what
7:21:51else you can do? Right? You can also
7:21:54sort multiple columns. Okay. So what I
7:21:56mean by this? Now let's say I wanted to
7:21:59do something like that. Okay, give me
7:22:01name, give me the let's do category and
7:22:05also give me the price from products and
7:22:09now I'm just going to do order by so I
7:22:12wanted to do category in ascending order
7:22:15and I wanted to do price in descending
7:22:17order. So this also you can do. So if I
7:22:20now save this and let's see what we are
7:22:22getting. So clear this and run it again.
7:22:25So you can see that for price this will
7:22:27be in the ascending order sorry
7:22:29descending order and the category will
7:22:30be in the ascending order. Okay.
7:22:33So now uh what else I think for this one
7:22:35this will be more than enough right? We
7:22:36don't have any uh anything else to
7:22:38discuss. Let's move to the next one
7:22:40which will be limit and offset that we
7:22:43need to discuss. So I'm just going to
7:22:44create one more here and let's give this
7:22:46one as underscore limit offset example.
7:22:50Okay.
7:22:52And pagination something like this.
7:22:55Now these all are very very practical
7:22:57thing. Okay. Now these you're going to
7:22:58use let's say you're implementing pagin
7:23:00essence. You have to implement all this
7:23:01logic correct. Now also this is basic
7:23:05pagination. I'm not going go into much
7:23:07complicated things. Now what actually
7:23:09limit and offset means so that you need
7:23:11to understand. So limit means how many
7:23:14rows you want to return. Okay. So limit
7:23:16means how many rows you want to return
7:23:22and what will be the offset. So offset
7:23:26will be controls so offset is going to
7:23:30control how many rows we want to skip.
7:23:33So this will be how many rows
7:23:37we want to skip. Right? So now let's say
7:23:42how it will work. So for example, you
7:23:44have a task that you only want to return
7:23:46the five products. Okay. So I wanted to
7:23:49return five products and I wanted to
7:23:51sort the name of the product in
7:23:53ascending order. So this is the query
7:23:55you have to write. So how you can do
7:23:57that? So let's say I wanted to do name,
7:23:59give me name, give me the price of that
7:24:02product,
7:24:04right? And here I'm just going to do
7:24:05this one as
7:24:07from products.
7:24:11Now I first I wanted to apply my order
7:24:13by
7:24:16name and this will be ascending
7:24:18and now what you have to do you have to
7:24:20give a limit property sorry this will be
7:24:22limit property and then because I wanted
7:24:25to return only five products so I wanted
7:24:27to give the limit as five so this is
7:24:29going to do what it's going to give me
7:24:31selective columns all the concept you
7:24:32have discussed previously so this is the
7:24:35concept of selective columns this is
7:24:36from where I wanted to get this is going
7:24:38to order by means it's going to do the
7:24:40sorting on name based on ascending order
7:24:42and this will be the limit when this
7:24:43many products I wanted to fetch and if I
7:24:46now clear this let's run it here
7:24:50I'll copy this
7:24:52and you can see that you're getting only
7:24:54five products right now remember it's
7:24:56also going to do the this order by based
7:24:59on name right it's going to do the in
7:25:01ascending order and you are only getting
7:25:03now let's say if I wanted to do price
7:25:04here price I wanted to do in ascending
7:25:07order now this will completely change
7:25:08now you can see that you're getting in
7:25:10ascending order. If you want to do in
7:25:12descending order, you can also do that.
7:25:14So you can let's say clear this and run
7:25:17it again. So you are going to get in
7:25:18descending order. But you are always
7:25:20going to get only five products because
7:25:22you are limiting the query by five
7:25:24products. Okay. So this is the use of
7:25:26limit. Now also now let's say in
7:25:29normally what will happen in the
7:25:30pagination. So in the first page you are
7:25:32going to get so this is page number one
7:25:34you're going to get five products. In
7:25:36page number two you're going to get five
7:25:37products. Or let's say you're going to
7:25:39get the product from zero sorry 6 to 10.
7:25:41Why? Because in first page you only have
7:25:45get the five products. So you're going
7:25:46to skip in third page again we are going
7:25:48to skip all 10 products because in the
7:25:51previous two pages we have already
7:25:52rendered those products. So we don't
7:25:54want to render. So this is where the
7:25:55concept of offset comes. Okay. So let's
7:25:58say what I need to do right I wanted to
7:26:01show on page one example that we wanted
7:26:03to do offset. Offset how offset is going
7:26:06to work. So offset zero means we don't
7:26:09want to skip anything. Offset five means
7:26:12we wanted to skip five products. You're
7:26:14getting what I mean? So let's do page
7:26:16one example. So consider you're
7:26:17implementing a page incent and I'm
7:26:19implementing the page one uh products.
7:26:22Okay? Or the query. So I'll do name give
7:26:24me price from products.
7:26:29Let's do order by only. Okay. So I'm
7:26:30just going to do order by based on name
7:26:32and I'll do ascending order only. And
7:26:34here I'm just going to do limit five.
7:26:36And now I need to do offset. So offset I
7:26:40wanted to give zero. Why? Because when
7:26:42you're going to render the first page
7:26:45products, you are not going to skip
7:26:47anything, right? Because in the first
7:26:48page, you need to render all the first
7:26:50products. So your offset will become
7:26:52zero. So now if you just do this one,
7:26:55right? First of all, clear this.
7:26:57[snorts] And if I just run this, so
7:26:59you're going to get five products. And
7:27:00these will be the five products, the
7:27:02first five products. Okay. Now let's see
7:27:04how page two will look like. So I'm just
7:27:06going to copy exact same thing and then
7:27:09I'm just going to paste it here. What
7:27:10will be the difference in the page two
7:27:13what you have to do right? You have to
7:27:14give a offset of five. Why? Because for
7:27:16the page one you've already rendered the
7:27:19five product. When you're going to
7:27:20render the page two you want to skip
7:27:22those five products and you want to
7:27:23render the next set of products. Okay.
7:27:26So if I now save this let's see how this
7:27:28is working. And you'll see that [snorts]
7:27:29if I clear this right and next time if I
7:27:31render you can see that both the page
7:27:34record is different because this is a
7:27:36first page data this is a second page
7:27:38data in the second page we already
7:27:40skipped this one because we've already
7:27:41rendered this five in the first page so
7:27:43this is the concept of offset
7:27:46now how the practical API example look
7:27:49like right so in the practical example
7:27:52what will happen right normally this is
7:27:53how it will look so consider you have if
7:27:56I'm not wrong so it would be page page
7:27:58minus one into limit. So let's say you
7:28:02are in the page two. So it will become 2
7:28:05minus one. So into let's say you are
7:28:08rendering five products. So five. So
7:28:10that means how this will work. So let's
7:28:12say in the zeroth page you're going to
7:28:14render five for the second page. So this
7:28:16will become five. For the third page
7:28:19this will become 3 - 1 into 5. So this
7:28:24will become 10. So when you're going to
7:28:26go to the third page, your offset will
7:28:28become 10. Correct? Because in the first
7:28:30page, you've already rendered five
7:28:32products. In the second page, you
7:28:33already rendered five products. So total
7:28:3510 products. So in the third page, you
7:28:37want to skip 10 products. Correct?
7:28:39Because you want to render from 11th
7:28:41product. So this is how it will look. So
7:28:43let's say if I just do same thing,
7:28:45right? So this will be my third page
7:28:47example here. So this will become 10. So
7:28:49I wanted to skip 10 products because I
7:28:52already rendered and you are going to
7:28:54get the last set of products. So this
7:28:57will be your concept of limit offset and
7:29:00pagenation. Okay. So now uh I'm going to
7:29:04pause here. It's not pause for you but
7:29:06I'm going to pause and then we I'm going
7:29:08to start in the next part the update
7:29:10part and delete part. So let's see how
7:29:12we we are going to do that in the next
7:29:13section. All right. So moving to the
7:29:15next one. So let's create the next file
7:29:17which will be how we are going to update
7:29:19single row. Okay. So I'll do update
7:29:21single row dosql.
7:29:24So let's see how we are going to update
7:29:25data. This is also very very important.
7:29:27Okay. So first of all let's do one
7:29:29thing. Let's see that you can see that
7:29:32we have this particular product right.
7:29:33So we have this mechanical keyboard
7:29:35electronics blah blah. So [snorts] what
7:29:36I'm going to do right. So first I'm
7:29:38going to see that whether this data is
7:29:40present or not. So I'm just going to do
7:29:41select name. Let's take price. Let's
7:29:44take stock and also I'm going to take
7:29:46the skew. So I'm just going to do from
7:29:49products and then I'm simply going to do
7:29:51where skew is equal to. So let's copy
7:29:54this. Right? So I'm just going to copy
7:29:56this
7:29:58and then I'm just going to paste it
7:29:59here. Okay. So this is the first thing.
7:30:02So now let's go here and let's say I'm
7:30:04just going to do clear
7:30:07and let's run this file.
7:30:14All right. So we have one data fine. Now
7:30:17my task is that what I need to do right.
7:30:19So let's say I wanted to update the
7:30:22price from 349 to something else and
7:30:25also I wanted to change the stock from
7:30:2715 to 23. So how I can do that? So first
7:30:30of all what we need to do right we need
7:30:32to do update right? So we are simply
7:30:34telling that we need to update this
7:30:36particular product. But where we want to
7:30:38update? So we wanted to update in a
7:30:40table right? So you always need to give
7:30:41the table name. So I want to update in
7:30:44the products table. Now next will be
7:30:46what you want to update. So this will be
7:30:48set that okay set means okay this will
7:30:50be my new value. So I wanted to set some
7:30:52value. So set will be that okay I wanted
7:30:54to make the price as 119.00
7:30:58comma you can update multiple properties
7:31:00also rows also and I wanted to update
7:31:02stock from 15 to 23. That's it. But this
7:31:06is not the case. Why? Because this is a
7:31:08single row update. So you need to tell
7:31:10that okay because your SQL doesn't know
7:31:12right that which product you wanted to
7:31:14update you can have 100 product thousand
7:31:16product lots of products. So here we
7:31:18need to use where clause not wear clause
7:31:20where filter so [snorts] here I'm just
7:31:22going to do skew and then I'm going to
7:31:24simply tell that okay you are updating
7:31:25this particular product here. Okay so
7:31:29I'm simply telling that update products
7:31:31table change the price from that
7:31:33particular value to 119.00 0 0 5 0
7:31:36whatever you wanted to give stock I
7:31:38wanted to update to 23 where the skew is
7:31:41equal to this skew
7:31:43I hope this is clear right so now what I
7:31:46going to do right let's copy this and
7:31:48then I'm just going to run it here so
7:31:50what I'm doing that I'm first checking
7:31:52if that is present I'm updating the data
7:31:54and then I want to see the updated data
7:31:57that whether the update is actually
7:31:59happened or not so now let's run it once
7:32:01again and we'll see that what is
7:32:02happening here okay so I'm just going to
7:32:04run here all right now you can See that
7:32:06we are getting 349. Now it's changed to
7:32:0811 1 9 stock changed from 15 to 23. It's
7:32:11very simple to understand the key that
7:32:13you need to know that how we going to
7:32:15set the data. Set data means you need to
7:32:17use this set whatever properties wanted
7:32:19update where this is the important part
7:32:21because you are updating a single row.
7:32:23Okay. So this is all about the single
7:32:25row update uh updated updates. Now
7:32:28[snorts] next will be uh let's take
7:32:30multiple rows. So I'm just going to take
7:32:3213. Let's do update
7:32:35multiple
7:32:37rows
7:32:38SQL. Okay. Now here first of all let's
7:32:43see what we can do. So first of all
7:32:45let's do one thing. Let's see we have
7:32:47some stationary product right. So this
7:32:48stationary product that we have. So
7:32:51first I want to see that okay how many
7:32:53stationary product I have. Okay. So that
7:32:55will be my first step. So let's do one
7:32:56thing. So I'm just going to do select.
7:32:58So do name. Give me also category. also
7:33:01give me price and let's say I wanted to
7:33:03also get the is active from where so
7:33:06from products table and then I'm simply
7:33:08going to do where I wanted to check the
7:33:10category is equal to stationary so I'm
7:33:12just going to copy this and let's paste
7:33:14it here okay so this is the first thing
7:33:16copy this sorry save this and then let's
7:33:18run it first let's copy here
7:33:24and then I'm simply going to paste it
7:33:28so we have two data makes sense
7:33:31what I need to do right so let's say you
7:33:33have some requirement that what you need
7:33:34to do you need to update all the
7:33:36stationary products prices these prices
7:33:39by 10%. So you have to increase that.
7:33:41Okay. So how we are going to do that?
7:33:44Now here definitely you don't want to do
7:33:46let's say you have 1,000 data you you
7:33:48are going to do single single update. No
7:33:50right. So there has to be some way that
7:33:52where you actually update all the
7:33:54products price by 10% at once. So to do
7:33:58this what we can do right simply I'm
7:34:00just going to do update
7:34:02and in this update so we are going to
7:34:04simply again this is same products. So
7:34:06I'm just going to do set and I'm going
7:34:08to do okay price now equal to so I'm
7:34:10going to take a round and I'm simply
7:34:12going to say that okay this price will
7:34:14now become 10% more or whatever you want
7:34:17to do let's say you want to increase by
7:34:18+ 10 whatever you want to do for now I'm
7:34:20just going to increase by 10% and I'm
7:34:22going to take this one comma 2 right so
7:34:24round two means it's going to keep our
7:34:26two decimal places sorry this will be
7:34:27two and now the important part how you
7:34:30are going to update also here you need
7:34:32to just pass that okay where the
7:34:33category is stationary so where the
7:34:35category is stationary simply telling
7:34:37that take all the stationary products
7:34:40increase the price by 10% and then you
7:34:42can also check it once again right so
7:34:43I'm just going to copy this and then you
7:34:45can run it here save this and you can
7:34:47see that what we are getting right so
7:34:49let's clear this run it again and you
7:34:52can see that this is increased by 10%
7:34:54this is also increased by 10% right so
7:34:5625 into 10 into 10% 2.5 so this is 27.5
7:35:00and you can see this is updated in both
7:35:02the rows so this is how you can update
7:35:04multiple column s at once. You can also
7:35:07do right. So let's say uh what you want
7:35:10to do right you want to mark out of
7:35:12stock products inactive. So how you can
7:35:14do that? So to do this one what you can
7:35:16do right you can just do update and
7:35:18let's say you want to do products and
7:35:20then you want to do set is active equal
7:35:23to false. So you're changing all from
7:35:25true to false where the stock is equal
7:35:29to zero. So this is going to do what?
7:35:31whenever there will be any products that
7:35:34is out of stock. So zero means it's out
7:35:36of stock. So you're setting that product
7:35:38as inactive. That's it. And then you can
7:35:40if you want to check it. So you do
7:35:42select name stock and let's say is
7:35:45active from products.
7:35:49And then I'm simply going to do where is
7:35:52active is equal to false. Okay. So this
7:35:55is where you're going to get this one.
7:35:57So I'm just going to comment it out
7:35:58here. Save this.
7:36:01Clear this and let's run it again. So
7:36:03you have only one. So this is changed to
7:36:05false. So we have old monitor. Let's see
7:36:08where we have old monitor and this is
7:36:09the stock is zero. So we're changing
7:36:11this one to false. Okay. But this is how
7:36:14you can update multiple product at once.
7:36:17Okay. Okay. So let's move to the next
7:36:19one which will be delete functionality.
7:36:21So for delete what I will do right. We
7:36:22are going to add one particular data and
7:36:24then we're going to delete that data
7:36:26only. So we we will not delete any of
7:36:28the existing all these data. So first
7:36:30let's insert one data here. So I'm just
7:36:31going to do insert into products and
7:36:35what are the things? So we have name, we
7:36:37have category, we have price, let's add
7:36:41stock. So skew and also we are going to
7:36:44have the description. So here we will do
7:36:47values. And now let's do here temp
7:36:51product
7:36:53to be deleted. Means we going to delete
7:36:55the same product.
7:36:58Then take uh category. So I'm just going
7:37:00to take this one as electronics only.
7:37:03Let's do here uh price maybe 345.45.
7:37:08Stock let's take 45. SK I'm just going
7:37:10to do electronic temp 009 or 013
7:37:14whatever you wanted to take. And what
7:37:17else? I'm just going to do uh temp
7:37:20product disk. So this is going to insert
7:37:23that product. And now what I wanted to
7:37:25do first I wanted to check if the
7:37:27insertion is done or not. So I'm just
7:37:28going to select name category and skew.
7:37:32So I'm just going to do prop from
7:37:34products. And here I'm just going to
7:37:36check where skew is equal to this skew
7:37:41that we have added this one. So copy
7:37:43this and I'm going to paste it here.
7:37:45Okay. So this will be my first step. So
7:37:47now let's run it. So I'm just going to
7:37:51copy this.
7:37:54Okay. So we have one data that we have.
7:37:56Sorry. Yeah. One data that we are going
7:37:58to delete. So now we need to delete
7:38:00this. Now deleting is very simple. So
7:38:02first what we can do right. So let's
7:38:04comment it out because we've already
7:38:06inserted that into our DB and then I'm
7:38:08just going to do here delete. So delete
7:38:11word you have to use from where? From
7:38:13products. So this is the table. And then
7:38:15simply mention that okay where the skew
7:38:17is equal to this particular skew simple
7:38:20and this will delete and then you want
7:38:22to check it. So just copy this and then
7:38:25just paste it here again. So simply we
7:38:27are first checking if this present then
7:38:28we are deleting and then we are checking
7:38:30again if that is present. So in that
7:38:32case it should not give any result.
7:38:34Okay. [snorts] So if I just go here and
7:38:36let's run it. So I'll do clear run it
7:38:38again. You can see that first time you
7:38:40have deleted one and then you don't have
7:38:42anything else. Now there are much
7:38:44nothing much to discuss here. These
7:38:46things are very very simple but this is
7:38:48how you need to delete. So moving to the
7:38:50next one which will be the last one in
7:38:52this particular section which will be
7:38:53you need to understand what is returning
7:38:56concept. So I'm just going to do 15 and
7:38:58let's do this one returning after insert
7:39:02dosql. So here what returning is going
7:39:05to do? Returning is going to gives back
7:39:07the affected rows after you will do
7:39:10anytime insert update or delete. So I'm
7:39:12just going to do returning usually
7:39:15returns back
7:39:18the rows returns back the rows
7:39:22immediately
7:39:24after
7:39:26insert or let's say you're doing update
7:39:29or whatever even you are doing uh doing
7:39:31delete. So here this is actually
7:39:34extremely helpful and you'll see that
7:39:35even if I'm created I created any videos
7:39:37previously on posgress for our DBs I
7:39:41have used this one in multiple places.
7:39:42Okay so whenever I'm going to insert
7:39:44something immediately I wanted to check
7:39:46that okay return me that inserted data
7:39:48to see that whether it is done or not as
7:39:50simple as that. So to do this you have
7:39:52to do insert into first you have to give
7:39:54the table name and here again pass the
7:39:56name category then what we have we have
7:39:59the price we have the stock we have the
7:40:02skew and also you have the description
7:40:04right so all these things and then let's
7:40:05say I wanted to do values and then I'm
7:40:07just going to do maybe let's take any
7:40:09random webcam camera
7:40:13uh I'm just going to do this one as
7:40:14electronics
7:40:17let's give some price
7:40:20uh talk and also webcam camera
7:40:26description. Okay. So now what I need to
7:40:30do I need to return back. So I wanted to
7:40:32see that if the insertion is done or
7:40:34not. So for this one we need to do
7:40:37returning. We have to use returning. So
7:40:40what I need to return. So once the
7:40:43product is now added. So what will
7:40:44happen? Postgress is going to create a
7:40:46UID right? So that will be a unique ID.
7:40:49So I will be having the ID. Similarly in
7:40:51MongoDB you are going to have something
7:40:52called uh underscore id. Remember this
7:40:55is a document ID. So similarly we are
7:40:57going to have the ID. So I wanted to see
7:40:59that actually the product is created. If
7:41:01the product is created I will be having
7:41:03some ID. I'll be having the name. I
7:41:05wanted to return the category. I wanted
7:41:07[snorts] to return the price. I wanted
7:41:09to return the stock and also let's say I
7:41:11wanted to return created
7:41:14add. So this is what I wanted to do.
7:41:16Okay. So now can save this and let's say
7:41:20we are going to run this. So let's clear
7:41:22this
7:41:24rename copy this and let's run it here.
7:41:30What you're getting insert has more than
7:41:34name 1 2 3 4 5 6
7:41:41oh skew we haven't added my bad man. So
7:41:44you have to do electronic
7:41:46uh let's do webcam 009.
7:41:50So now let's save this clear this and
7:41:53now we going to run it again and we'll
7:41:54see what we're going to get
7:41:57and you can see that we have ID name
7:41:58category price stock created. So you're
7:42:00getting the data right and you see that
7:42:02immediately it's returning right so this
7:42:04is your unique ID it's created. So this
7:42:06is what returning usually does. So it's
7:42:09return back the result or the rows
7:42:11immediately after your insert. You can
7:42:14also use update right. So let's say
7:42:16you've done insert right. You can also
7:42:18use update and then you can return the
7:42:20data also. For example let's say I
7:42:21wanted to update products
7:42:24and then I wanted to do set
7:42:28I wanted to set the stock is equal to
7:42:30stock + 10. So here it will become 56.
7:42:35Let's do 11. So 67 and then I'm just
7:42:37going to do where skew is equal to this
7:42:41skew just now I have created. Okay. So
7:42:43where the skew is this and then I wanted
7:42:45to use returning. So here also you can
7:42:47return ID name and then also let's say
7:42:50you want to return the stock. So what
7:42:51you're doing you're updating the product
7:42:53where the SQ is this and then at the end
7:42:55you're using returning. So returning
7:42:57clause you're using which is going to
7:42:58return. So I'm just going to clear and
7:43:00then if you run again you can see that
7:43:02now this will become 67. Okay. So the
7:43:05stock
7:43:07all right so I think this is done same
7:43:08also you can do for delete also let's
7:43:10say you want to delete this you can use
7:43:12delete from products where skew is equal
7:43:18to this
7:43:22and then you are going to use returning
7:43:25so you're going to return the ID name
7:43:27and the skew so this is going to delete
7:43:29and if you want to see that if the
7:43:31delete is successful or not you'll see
7:43:32that if I use select now right that
7:43:35product will not be present because that
7:43:36will be deleted. So I'm just going to do
7:43:38form. So this will become products where
7:43:41the skew is equal to this.
7:43:46Save this and see what will happen.
7:43:51You can see so this is deleted. So
7:43:52you're getting the ID name and once the
7:43:55delete is deletion is successful you you
7:43:57don't have that product present. So this
7:44:00is how you can use the returning
7:44:02concept. Okay. So this is very very very
7:44:05helpful. So with this I think we have
7:44:07completed the part two and now let's
7:44:09move on to the next one which will be
7:44:10our last part. So there we are going to
7:44:12cover some of the little uh I not say
7:44:15advanced concept but intermediate to
7:44:17advanced level of concept. We need to
7:44:19understand [snorts] the concept of
7:44:20foreign keys one to many relationship
7:44:23many to many inner join left join
7:44:26aggregate functions group by the having
7:44:29all these things we're going to cover in
7:44:31the next section. All right. So now we
7:44:33are almost at the end of section which
7:44:35will be part three. Not here we have to
7:44:38create outside and this also is very
7:44:40very important. So we are going to cover
7:44:42relationship uh joins aggregate
7:44:45functions group by indexes all these
7:44:47things. Okay. And first file will be so
7:44:49for this one what we going to do right
7:44:51we going to create a reset and seed
7:44:55relationships.
7:44:57So we are going to first add our data
7:44:59then only after that we'll be able to
7:45:01start uh understanding all the concepts.
7:45:04So first what we going to do right? So
7:45:05let's create the extension. I'm not
7:45:07going to explain most of the things
7:45:08because these things we have already
7:45:09covered in the previous part. Extension
7:45:13if not exist and I'm just going to use
7:45:16pg crypto.
7:45:19Okay. Now what we going to do right? See
7:45:22these will be relationship sections
7:45:24right? So what we need to do we can't
7:45:26have one single table. We need to have
7:45:27multiple tables so that we can
7:45:29understand the relationship between
7:45:30tables the properties and everything. So
7:45:33first I'm going to drop some of the
7:45:34tables in case we have all those tables
7:45:36so that we can start fresh. So I'm start
7:45:39with drop tables if exist. So we going
7:45:42to have one post tags table. Copy this.
7:45:46We also going to have one more table
7:45:48that will be for comments. So comments
7:45:50table we also going to have one for post
7:45:53table one will be for only tags and at
7:45:57the end we are going to have one for
7:45:58users. Okay. So these many tables we are
7:46:02going to have now let's create all the
7:46:04tables one by one. It's very very
7:46:06important to understand all these things
7:46:07that what are the properties that we are
7:46:09taking. Why? Because our entire section
7:46:11this part three will be dependent on
7:46:13these tables only. Okay. So let's start
7:46:15with the first table. So I'm just going
7:46:17to do create table and I'm start with
7:46:19maybe let's do users. Okay. So in the
7:46:21users first I'm going to have a ID u ID
7:46:24and this will be my primary key and here
7:46:28I'm just going to take a default
7:46:29property and I'm just going to take here
7:46:31gen random uu id. Okay. So this will be
7:46:35the ID of that user. All right. So now
7:46:38after this I'm simply going to take one
7:46:39more property. Let's take a name. So
7:46:41every user is going to have a name and
7:46:43this will be not null. Okay. So these
7:46:46two things we are going to have for this
7:46:47particular table. Now moving to the next
7:46:49one. Next will be our second table which
7:46:51will be create table posts. Now this
7:46:55will become now very very important.
7:46:57Okay. So first every post is going to
7:46:59have a ID. So I'm just going to copy
7:47:00this and then we're going to paste it
7:47:02here. And now this is where we are going
7:47:05to start our relationship. So every user
7:47:08can create multiple post. So that means
7:47:09there has to be some relation so that we
7:47:11can understand okay this particular post
7:47:13is created by which user. So we are
7:47:16going to have a user ID property and
7:47:18this user ID will be my user ID of this
7:47:21particular table. Right? So that let's
7:47:23say we have a post five fifth post is
7:47:26created by user number two. So from this
7:47:28user ID I will be able to understand
7:47:30okay this is created by user number two
7:47:32whose ID is this. So here we are going
7:47:34to have UID which will be not null. And
7:47:37now we are going to understand one very
7:47:38important concept that is references. So
7:47:40how we are going to tell that okay this
7:47:41user id belongs to this particular users
7:47:44do id. So this is where we are going to
7:47:46have something called references. These
7:47:49references now I'm going to tell okay
7:47:51this is my users table and this will be
7:47:53my ID. I hope this is clear. Next let's
7:47:56take a title for every post. We going to
7:47:58take a title.
7:48:01Sorry if you're getting any noise. I
7:48:03think it's some bike noise from outside.
7:48:05It's coming. These people are crazy.
7:48:07Okay, so title I'm just going to take
7:48:09text and this will be not null. And then
7:48:12I'm also going to take a status for
7:48:14every post you're going to have a status
7:48:16because later when we going to
7:48:18understand the concept of where group by
7:48:20having all these things this actually is
7:48:23needed this particular property. So for
7:48:25this one you're going to take this one
7:48:26as text and I'm just going to do not
7:48:28null. Let's take a default property and
7:48:30for default I'm going to maybe let's
7:48:32give this one as wrapped. And here I'm
7:48:34also give a check property. So let's
7:48:36give a check property for this. So I'm
7:48:38just going to do this one as status. And
7:48:41status I'm going to give in. So it can
7:48:43be either dropped or it can be either
7:48:46published.
7:48:48Okay. So this is another property. Next
7:48:51what else we can take? So let's take one
7:48:54views property. So here I'm just going
7:48:56to take a views property which will be
7:48:58integer. I'm just going to take not
7:49:00null. Let's take a default. I'm going to
7:49:02do zero. Let's take a check property and
7:49:05here I'm just going to take views. These
7:49:07views has to be greater than or equal
7:49:09zero. So this is the check that we are
7:49:11going to have. So these all the
7:49:13properties this post table is going to
7:49:15have. Then we going to take our comments
7:49:18table. Now let's create again. So do
7:49:20create table and I'm going to do
7:49:22comments. For this one again we are
7:49:24going to have the ID. So copy this
7:49:27paste it here. Now what else this is
7:49:29going to have? Every comment that you're
7:49:31going to have will be associated to some
7:49:33post, right? Let's say you're using
7:49:35Facebook or Insta for a particular post.
7:49:37There can be thousands of comments. But
7:49:39you need to identify that okay, this
7:49:41comment is belongs to which post,
7:49:43correct? So that is the reason we need
7:49:44to have one more reference set which
7:49:46will be post ID. And here you have to
7:49:48take UID and this will be again not
7:49:50null. And here you have to take
7:49:52references. And then I'm just going to
7:49:55denote to my post
7:49:58reference to my post table and it will
7:50:00reference to this post id. So I'm just
7:50:02going to give this one as id. Okay. And
7:50:04then also let's take a body which will
7:50:06be make actual comment. So this will be
7:50:08text and I'm just going to give this one
7:50:10as not null. So these three things our
7:50:12comments table is going to have. Okay.
7:50:15So now uh next what else we have? We
7:50:17also need to take our tags table. So I'm
7:50:19just going to create one more table.
7:50:21Let's give this one as tags. Let's take
7:50:24our ID.
7:50:26Okay. And here I'm just going to take a
7:50:28name. I'll do text not null. And for
7:50:32every tag it has to be unique. So I'm
7:50:34going to take a unique property. Okay.
7:50:36And then at the end we are going to have
7:50:38our post tags. Uh now this is actually a
7:50:41junction table. And why actually you
7:50:43need it? Now let's say one particular
7:50:45post can have multiple tags and one tag
7:50:48can belongs to many posts. Now I I know
7:50:50that this might be little tricky for
7:50:51someone uh like if you're a beginner to
7:50:53understand but if you give little bit of
7:50:55time you'll see that everything is
7:50:56actually connecting or connected with
7:50:58each other and this is actually called
7:51:00many to many relationships. So I'm going
7:51:02to repeat once again this post tags. So
7:51:04one post let's say you have one post
7:51:06that can have multiple tags but one tag
7:51:09let's say there is a tag ReactJS. Now
7:51:11you have one particular post and that
7:51:13particular post has a tag reactjs and
7:51:16this particular reactjs tag can belong
7:51:18to multiple post right so let's say you
7:51:20have 10 post and this reactj tag can be
7:51:22present in five post so that means one
7:51:25post can have many tags one tag can
7:51:28belong to multiple post so it's a many
7:51:30to many relations so here what I'm going
7:51:32to do I'm just going to create one more
7:51:33create table and let's give this one as
7:51:36post tags and here what we need to do
7:51:39right now Remember here we need to have
7:51:42a post id because one post can have
7:51:45multiple many texts. We need to
7:51:46understand that this is belongs to which
7:51:47post? This will be UID
7:51:50uh not null and I have to give
7:51:52references and this will be post table
7:51:55id
7:51:56and then I'm also going to have a tag
7:51:58id. So I'm just going to do tag ID. This
7:52:01is also u ID. So I'll do not null. Let's
7:52:04do references. And this will be this
7:52:06particular tags table that we have
7:52:07created. So this will be tags id. Okay.
7:52:10So this will be the relations and also
7:52:13let's take we need to take a primary key
7:52:15here. So what actually we are doing
7:52:16here? We are going to take a composite
7:52:18primary key. That means these pair that
7:52:20whatever we are taking that must be
7:52:22unique. Okay. Why? Now you might ask me
7:52:25why? Because if you have one particular
7:52:27post the same post cannot be connected
7:52:30to same tag twice. You are getting what
7:52:32I'm telling. So let's say you have a
7:52:33particular post and there is a tag
7:52:35ReactJS. You can't add that same ReactJS
7:52:38tag two times. Okay. So how you we can
7:52:41do that? So I'm just going to take a
7:52:42primary key here and let's pass this
7:52:44post id, right? And then you have the
7:52:47tag ID. So this is going to create a
7:52:49composite primary key. So these all the
7:52:53uh tables that we need. Okay. So we'll
7:52:55start with users ID and name. Post ID,
7:52:58user ID, reference, title, status and
7:53:00views. Comments ID, post ID because
7:53:03every comment is belongs to a post.
7:53:05Tags, this is just a unique tag. Uh and
7:53:08because this will be unique, right? Now
7:53:10this is important. This post tag, every
7:53:12post can belong to one tag and one tag
7:53:14can belong to multiple post. Okay, with
7:53:16a composite primary key. So now what I
7:53:19have done right, I actually have created
7:53:20all the data that we are going to seed.
7:53:23Now what is this? So these are the dummy
7:53:24data that I'm going to add and based on
7:53:26this data we are going to understand all
7:53:28the concept one by one. But let's do
7:53:30this one in the next part. Till this
7:53:31part this is all the tables. Do this you
7:53:34can pause this particular part. I will
7:53:36highly suggest and try to go through all
7:53:39the properties or all the rows that we
7:53:41have created for each and every table.
7:53:42It's very very important to understand
7:53:44all the concepts that we are going to
7:53:46discuss in the next part. All right. So
7:53:47let's add all the data one by one and
7:53:49then we are going to run this particular
7:53:51file because until unless we're going to
7:53:52seed our data in our DB and create the
7:53:54tables we can't start all the concepts
7:53:56like foreign keys one one to many
7:53:58relations many to many relations inner
7:54:00joint lab join so many things are there
7:54:02so first [snorts] let's uh copy this one
7:54:04so I'm just going to copy this paste it
7:54:06here and see what we are doing simply we
7:54:08are inserting the two users we have two
7:54:11users on and Rahul into our users table
7:54:15then add uh these three I'm going to
7:54:17copy and I can clearly understand what
7:54:20we are doing here. It's not that much
7:54:21difficult to understand. So we are
7:54:23inserting into post table user id title
7:54:27status and views right. So here ID how
7:54:31we going to get so from users where the
7:54:33name is this particular name because
7:54:34we've already added this in our users
7:54:36table. So we have added two post here
7:54:39and one is for Rahul user one post.
7:54:42Okay. Next let's copy these two. We also
7:54:46need to add some comment. So I'm just
7:54:48going to paste it here. So what actually
7:54:50we doing? We are inserting comment post
7:54:52body.
7:54:54So id ID how we are going to get? So
7:54:55from a post you can see that this
7:54:57postgress SQL join explained this is one
7:54:59of the post that I have added here. So
7:55:01this id is belong because we already
7:55:03have the relations in the comments
7:55:05table. If you go to the comments table,
7:55:07you'll see that there is a relations
7:55:08with post ID which is your post ID. So
7:55:11that means when we we are setting this
7:55:14particular data this id we are going to
7:55:17get from post where the title is equal
7:55:19to this and this will be for this
7:55:21particular title. Now you see back end
7:55:23API with posgressql this is created by
7:55:26Rahul user and this is created by this
7:55:28particular postgress SQL join explain is
7:55:30created by on my user. Okay and [snorts]
7:55:33then I think let's add uh this tag. So
7:55:36I'm also going to add two unique tag. So
7:55:38let's add this into our tag. So you have
7:55:40SQL and back end. That's it. Next, we
7:55:44also need to add our post tag. And then
7:55:47at the end, we're going to have our uh
7:55:49select message. So see what we doing
7:55:52here. So for this one, what we doing,
7:55:54right? So post ID, we have the post ID
7:55:55and the tag ID, remember? So we taking
7:55:58some allis. So from post we are taking
7:56:00as a T. Tags we're taking as a T. So you
7:56:03take the post ID and the tag ID where
7:56:05the post title is postgql joint explain
7:56:08and the tag ID is SQL because we have
7:56:09already added the SQL here. Okay. And
7:56:12the one we have added for I think uh
7:56:14backend tag. Okay. So this is going to
7:56:16insert in our post tag collection. And
7:56:19then we just logging this. Now save this
7:56:23and then we need to run this. Okay. So
7:56:25first let's clear this
7:56:29and I'm going to copy this.
7:56:32Let's run it here.
7:56:35Okay. So now this is going to create all
7:56:38of this. It's going to insert the data.
7:56:40And if you want you can just see all of
7:56:41this here also. If I now refresh this.
7:56:46See how slow this is. Man,
7:56:52I think this would solve this one very
7:56:55quickly. See, we have the commands, post
7:56:57tag, post, product, tags, and users. And
7:56:59if you right click here,
7:57:04so you can see that you can count rows
7:57:05and you can also view the data. If I do
7:57:07all rows, right, this will load forever.
7:57:10So for now, I'm not going to do that. If
7:57:12you're using Windows, right, just do
7:57:13right click and do view data. you'll be
7:57:14able to see all the data that we have
7:57:16created here. Okay? Or else you can also
7:57:18directly um do from here. Right? So for
7:57:21example, let's say uh I'll [snorts] just
7:57:23do here only. Right? Maybe let's do
7:57:24select
7:57:28select star from and then you're going
7:57:31to give all the tables and everything.
7:57:33For example, let's say post tags, right?
7:57:36Something like this. And then you'll be
7:57:37able to do that also. I think we have
7:57:39already done this one part one and two.
7:57:40I'm not going to do that one. It's just
7:57:42going to take some time. So what I mean
7:57:43by this whatever data we have added or
7:57:46we done the sitting in our DB you'll be
7:57:48able to see that uh easily in the DB you
7:57:50can just do that right click and do view
7:57:53data. So go here any of the table do
7:57:55right click you see it's very slow for
7:57:57me I don't know why and then you do view
7:58:00and then you'll be able to see the rows
7:58:01directly from here. Okay. So now now we
7:58:05need to start uh all the concepts one by
7:58:08one because you already have very good
7:58:11idea that how many tables we have what
7:58:13is the relations okay if you want you
7:58:15can just go through one by one more time
7:58:17it's very very important to understand
7:58:19right that for example user is has a
7:58:22relations with post has a relations with
7:58:24comments these tags are unique but when
7:58:27you have post tags this has relations
7:58:30with both post and the tag so now let's
7:58:32create our second file which will be
7:58:34foreign keysql.
7:58:39Okay.
7:58:41Now you know one thing these particular
7:58:43sections that we are going to do right
7:58:44this is these you need to learn the
7:58:46concept more than doing unnecessary
7:58:49example. Why? Because you if you can
7:58:51understand the relations joins all these
7:58:53things you'll be able to do any kind of
7:58:55queries you will be able to write. But
7:58:56if you don't understand let's you do 10
7:58:58example also and you don't know the
7:59:01basics it will be difficult for you to
7:59:02write in a real project. So what
7:59:04actually foreign keys are. So foreign
7:59:06key will be you can consider that as a
7:59:08column that is going to points to the
7:59:11primary key of another table. Okay. So
7:59:13I'm just going to write once again. So
7:59:15foreign key will be foreign key is a
7:59:18column in sort that points
7:59:22to the primary key of another
7:59:27table.
7:59:29Okay. So this will be the foreign key.
7:59:31Now just take one very simple example.
7:59:33So you have users do ID which is a
7:59:36parent key and then you have post dot
7:59:41user id. Now this is the reason I
7:59:43mentioned that this is important. So go
7:59:45to post and see that post has a user ID.
7:59:48This is a foreign key. Why? Because what
7:59:50this is actually doing this is pointing
7:59:53to the parent key here. Parent uh sorry
7:59:56this is pointing to the another table.
7:59:58So this is pointing to the another
8:00:00table. So another table is users and
8:00:01this is pointing to the another table
8:00:03primary key. What is the primary key?
8:00:05ID. So ID is a primary key. So this is a
8:00:07proper example of a parent key and a
8:00:10primary key. Okay. And what actually
8:00:12this means? This means that every post
8:00:14that you're going to create that must
8:00:16belong to one existing users. So that
8:00:19means every post you will create
8:00:23that belongs
8:00:26to a that not belongs that must belong
8:00:30that must belongs or belongs to a to an
8:00:34existing users.
8:00:38Okay. So this is what it will be. So now
8:00:41uh maybe let's do one thing right. So
8:00:43let's see some simple example but this
8:00:45is all about the concept. So first let's
8:00:47see our parent table. So I'm just going
8:00:48to do here select let's do ID let's do
8:00:51name and I'm just going to do here from
8:00:54users table because we have the users
8:00:56table. Okay. And then what we going to
8:00:58do right then we are going to check our
8:01:00child table. So child table we will
8:01:01select ID. Now we have the user ID and
8:01:04then I'm just also going to take the
8:01:06title of that particular post. So this
8:01:08will be from my posts table. Okay. So
8:01:11save this and let's run it here. Okay.
8:01:14So let's remove this.
8:01:16And you can see that what you're
8:01:18getting. So you're getting two users.
8:01:20But if you [snorts] notice one thing,
8:01:21you see this part here. This part right?
8:01:25See there is a match. So this actually
8:01:28is belongs to this particular. So these
8:01:30two post that we have is belongs to user
8:01:33ona. And this particular post that we
8:01:36have is belongs to user Rahul. So there
8:01:39is a match. So this is a foreign key
8:01:41which points to the primary key of a
8:01:45different table or another table. Very
8:01:47important. So foreign keys points to the
8:01:49primary key of another table. This is
8:01:51the concept that you need to understand
8:01:52as simple as that. Okay. So I think
8:01:55that's all. I think we don't have
8:01:57anything much to discuss here. So let's
8:01:59move on to the next one which now we are
8:02:02going into much more important concept
8:02:04and that is now this is also important
8:02:06concept because this is you need to
8:02:08understand now see if you go here right
8:02:10this particular file that we have
8:02:11created and if you can understand this
8:02:13part whatever we are doing how do we are
8:02:15doing the differences and everything
8:02:17this will be like a piece of cake
8:02:19because it will be a very very simple
8:02:20for you to understand but if you don't
8:02:22know how your table structure is see
8:02:25that is the reason you see my teaching
8:02:27process or style right I Always focus
8:02:29the thing that is important. If you
8:02:31don't know this structure and someone
8:02:33will tell you this, it will be difficult
8:02:35for you to understand. I can 100%
8:02:37guarantee. Okay. So this is the thing
8:02:38that you need to understand. Now let's
8:02:40move to the next one which will be 03
8:02:43and I'll do one to many
8:02:46one to many
8:02:49uh relationship
8:02:51now relationship.
8:02:54Okay. So let's close now. I'll close
8:02:56this file. I'll open this one. So what
8:02:58actually one to many listen that means
8:03:00in simple sentence one parent row can
8:03:04have many child rows simple so we'll do
8:03:07one parent rows can have uh can have
8:03:12multi no many child rows many child rows
8:03:15okay what will be our example in our
8:03:18example one user can write many post so
8:03:21one user so user Rahul can have 10 post
8:03:25but one post is belong to one user. So
8:03:29what I mean by this? Let's see user one.
8:03:32So user one is Anunna and user two is
8:03:34Rahul. So Rahul can have 10 post. Let's
8:03:37say 1a 2a 3a 4 like that 10. But every
8:03:42post this single post always belong to
8:03:45one user. So this post also belong to
8:03:47Rahul. This post also belongs to Rahul.
8:03:50You're getting what I'm talking about.
8:03:52So that means one user can write many
8:03:56posts but one post will always belongs
8:04:01to
8:04:04no belong to one belongs to one user.
8:04:09Okay. So this is what it will be. So
8:04:12here if I want to explain in much more
8:04:14detail way so or much more simpler way.
8:04:18So users again is your parent table and
8:04:22then posts will be your child table.
8:04:28Okay. So this is about the concept. Now
8:04:31here although we haven't started our
8:04:33join yet but this is the this is all
8:04:35about the concept. Okay. This is one to
8:04:36many. Now one more thing I wanted to
8:04:39explain here that is let me just write
8:04:42here comment only. So you see this
8:04:45relationship right? This is a
8:04:46relationship correct? This is a one to
8:04:48many relationship. So here if I try to
8:04:51take post dot user id. So this actually
8:04:56relate to our user do ID. Right? This is
8:04:59what actually happening here. Correct?
8:05:01So simple words that this user do ID is
8:05:04your original user ID. This post do user
8:05:07ID stores this user ID inside the post
8:05:10table. Okay. This is also another very
8:05:12very important concept. Yeah. Okay. So
8:05:15here what I'm talking about that this
8:05:17users do ID please note it down this is
8:05:19actually important is the original is
8:05:22the original user ID and what this post
8:05:25dot I don't know I'll [snorts] make this
8:05:29control minus and then it will uh zoom
8:05:31out okay so this post dot user ID is
8:05:35nothing but it's the same user ID but
8:05:38this post dot user ID is going to stores
8:05:40that user ID only that original user ID
8:05:43only I'm draw that use original user ID
8:05:46inside the posts table. So this is what
8:05:50is happening here. Okay. So now although
8:05:53we haven't started our uh join yet,
8:05:55right? Because join is one of the most
8:05:57important concept. But I'm going to show
8:05:58you one example that uh that let's say
8:06:01someone tell you that okay give me all
8:06:03the post. So you have to give me all
8:06:05post with their authors.
8:06:07But you might be thinking okay I can
8:06:09give all the post very easily but in my
8:06:12post table I only have the user ID. How
8:06:16I'm going to get the username right? So
8:06:18this is the query can come here because
8:06:20I can give the user ID but I need to
8:06:22somehow get the username. So this is
8:06:24where the relations comes into picture
8:06:26because this user ID is nothing but this
8:06:28user ID. Correct? This ID. So if you
8:06:30know this user ID, you know this ID and
8:06:33from this ID you'll be able to get this
8:06:35name. Simple. So now what you can do
8:06:37right although again I'm repeating we
8:06:39haven't done the uh join yet but this is
8:06:42also another join concept only. So here
8:06:44I'm just going to do users okay dot
8:06:47name. So I need the username as I'm just
8:06:49going to do remember we have done the
8:06:51allis so use using as and this I'm going
8:06:54to take as author name and also give
8:06:56comma and here I'm going to take the
8:06:58posts dot title as post title but now
8:07:05also let's take the posts dot status I
8:07:08think we also have the status right but
8:07:10now how we are going to get this so now
8:07:12we need to work with two tables because
8:07:15this user name is not present in this
8:07:18post table. Post table only has the user
8:07:20ID. But to get the username, I need to
8:07:23query this user table. So that means I
8:07:25need to get from users table and at the
8:07:28same time I need to do a inner join.
8:07:30Okay. So this we are going to discuss
8:07:32later. For now just write it. So we're
8:07:33going to do a inner join with which
8:07:36table? Post table. Why we can do that?
8:07:38Because there is a relation between this
8:07:40user ID and this user ID here. So this
8:07:44will be inner join. And then what we
8:07:46need to do how we going to do that? So
8:07:48we need to check on so what we are
8:07:51asking that we need to give me all post
8:07:53right. So we are doing that. So all post
8:07:58with their authors right? This is what
8:08:02we're doing. So that means this user
8:08:05this user ID will be same as this ID. So
8:08:08when I'm going to do on so I need to
8:08:10check this user do id has to be equal
8:08:14post dot user id. So you're getting I'm
8:08:17repeating this thing that what you're
8:08:18doing simply you're checking that okay
8:08:19this user ID and both are same that
8:08:21means this is a match okay and then what
8:08:24you're going to do simply you can also
8:08:25do a order by so let's do order by so
8:08:27I'm just going to do order by and I'll
8:08:29do users dot name posts
8:08:35dot title
8:08:38okay so now what is happening here I'm
8:08:41going to repeat once again so we are
8:08:43simply telling that we are connecting
8:08:46ing user do ID with post do ID so that
8:08:49means if ona that user has written two
8:08:52post that user row will appear with two
8:08:55post you're getting what I'm talking
8:08:57about so this proves our concept of one
8:09:00to many relation so that mean one user
8:09:02row can be connected with multiple post
8:09:05rows simple and now why we are using
8:09:07inner join now that we going to discuss
8:09:08later because inner join normally it
8:09:11will do right it will going to return
8:09:12only rows where the relationship exit
8:09:15exist on the both sides. Okay. All
8:09:18right. So now let's run it here. Right.
8:09:20So I'm going to paste this. Sorry, not
8:09:22this one.
8:09:25So I'll just paste it here / this. And
8:09:28then if I do enter and you can see that
8:09:30what you're getting. So you're getting
8:09:31the post title author name. But now you
8:09:34are able to get the author name also for
8:09:36that corresponding post. And why this is
8:09:37happening? because we are doing a inner
8:09:40join and there is a match that if the
8:09:42user id is equal to post dot user id
8:09:44then only I'm going to get but this is
8:09:46where even though your post table don't
8:09:48have the username still using this
8:09:50relation you are able to get this
8:09:52particular name okay so this is although
8:09:54this we have we have discussed about
8:09:56inner join but this is the concept of
8:09:58one to many relationship so with that
8:10:00now let's move on to the next one all
8:10:02right so although we have to cover the
8:10:04many to many relations right but I
8:10:05thought that let's do the inner join
8:10:07first and left join and then we going to
8:10:09do that. Okay, it will be helpful. So
8:10:11I'll do inner joinsql.
8:10:14Let's close this one. Okay. So what
8:10:18actually inner join is right. So
8:10:20remember one thing is the key here that
8:10:23is interview questions. See this
8:10:25particular video right? Whatever we are
8:10:27doing everything can be interview
8:10:28questions because this is a conceptual
8:10:30and practical posgress course right. So
8:10:33whenever you're going for any interview
8:10:35let's say backend interview or whatever
8:10:36database interview you're giving there
8:10:38is a possibility that you're going to
8:10:39get a lot of questions from this
8:10:41particular video whatever we are
8:10:42learning. So inner join is going to
8:10:45returns this is important only the
8:10:48matching rows
8:10:51from both tables. So from both tables
8:10:55okay this is the important part here. So
8:10:57in our case I think we've already
8:10:58discussed that part right that in our
8:11:00post there is a user ID that points to
8:11:03our user table ID this ID again I'm
8:11:06going to repeat the same thing this user
8:11:08ID points to this user ID simple right
8:11:12so what postgress is going to do so
8:11:14postgress now will be able to match each
8:11:17post with the user that user actually
8:11:20created the post why because there is
8:11:22something some relations between these
8:11:24two if there is no match it's is not
8:11:27going to return anything simple okay so
8:11:29now let's create a simple example and
8:11:32you're going to understand everything
8:11:33that we are doing here okay and then I'm
8:11:35going to explain that what actually this
8:11:37example is doing and why I've actually
8:11:39decided to take this as example so I'm
8:11:41just going to do select
8:11:43I'll do users do name as I'm going to
8:11:46take this one as author name
8:11:49comma you have to give comma here and
8:11:51I'll do posttitle as post title
8:11:57Then I'm also going to take the posts
8:11:59dot status
8:12:02and also let's take posts dot views
8:12:04because we have the views also. So we
8:12:06have the views also. Okay. So these four
8:12:09things now from where because you have
8:12:10to give the destination always. So from
8:12:12my post table and now I need to see I
8:12:16need the username right because I
8:12:17already mentioned this thing multiple
8:12:19times that your post table don't have
8:12:21the username. So that means you have to
8:12:24get the username from your user table.
8:12:26So this is where you have to do inner
8:12:27join as simple. So you're going to do
8:12:29inner join with the users table and then
8:12:31you have to give a matching condition.
8:12:33So that is the reason I mentioned that
8:12:34it is going to return only the matching
8:12:36rows. So there has to be something there
8:12:38is a match. So what is the match? Post
8:12:40dot user ID is a match with user do ID.
8:12:43Simple. So here you're going to give
8:12:45that on. So we do on posts
8:12:49dot user id is a match with users do id.
8:12:53So it's a matching condition. So now
8:12:55this is going to do the inner join
8:12:56successfully. So postgress will be able
8:12:58to understand. And now what you can do
8:13:00right I'm just going to do a where. So
8:13:01let's do posts
8:13:04dot status because we have the post dot
8:13:07status right see and then while adding
8:13:09the post I've added this one right. So
8:13:11go here. So we have this published or
8:13:14dropped. So I'm just going to get that
8:13:16where the post dot status is equal to
8:13:19published
8:13:22and let's do order by also. So I'm just
8:13:24going to do order by and I'll do post
8:13:27dot views and I'm just going to do this
8:13:30and maybe let's do descending order.
8:13:32Okay. So this will be a perfect example
8:13:34of inner join. Now how we are going to
8:13:37read this if you're a beginner. So you
8:13:39start with the beginning right. So first
8:13:40from the post table what we are doing we
8:13:43are doing inner joining our users table.
8:13:46So simply in a simple way we are
8:13:48connecting each post to that particular
8:13:51user right and this is the matching rule
8:13:53I already mentioned this is the matching
8:13:55rule here sorry this is the matching
8:13:57rule so this is the matching rule
8:14:01without this it won't be possible and
8:14:03then we giving some condition that where
8:14:05it is published and then we're going to
8:14:06do order by and now if you run this see
8:14:09what will happen. So we're going to do
8:14:10clear
8:14:12and see what we're going to get.
8:14:16All right. So we're getting zero result.
8:14:18Published spelling is wrong. I know
8:14:20that. Okay. So this is wrong. Save this
8:14:23and run again.
8:14:28Okay. So now you're getting author name
8:14:30also you're getting post title, you're
8:14:32getting status published and also views.
8:14:34This is also in descending order. So
8:14:35you're doing a lot of things but the
8:14:37important part what we are doing here we
8:14:38are doing a inner join. So the interview
8:14:41questions that you might get that what
8:14:42actually inner join is what actually it
8:14:44will return and how actually it will
8:14:46work. So the most important part you
8:14:47have to mention that it's written only
8:14:49the matching rows from both tables but
8:14:52there has to be some matching condition
8:14:53because if there is no matching
8:14:55condition how posgress is going to
8:14:57understand that okay this particular
8:14:58post is written by this user you're
8:15:00getting. So this is where it is very
8:15:02very important. So now I think this is
8:15:05done. Let's move on to the next one
8:15:07which will be our left join.
8:15:13Okay. So close this. Now what actually
8:15:15left join will do. Now left join is
8:15:19going to keeps all rows from the left
8:15:22table. Now this might be a little tricky
8:15:24to understand. Okay. So let's write all
8:15:26the things first. So I'm just going to
8:15:27do left join keeps all rows from the
8:15:33left table.
8:15:36Okay. Now say that consider you have a
8:15:39left table and you have a right table.
8:15:41Now what this first condition is telling
8:15:43that this statement that it is going to
8:15:45keep all your rows from the left side
8:15:46table and if the right side table has
8:15:49the matching data then postgress is
8:15:52going to include that data. If not what
8:15:55possess is going to do? It's going to
8:15:56return null for the right side column.
8:15:59These things are very very important. So
8:16:00I'm just going to do so consider you
8:16:02have a two table left table right table.
8:16:04If the right table has matching data
8:16:10so in that case posgress is going to
8:16:13include that. Supposedly it's going to
8:16:14include that
8:16:17includes that if it's don't have any
8:16:19matching data.
8:16:26So in that case it's going to return
8:16:28null. It returns null.
8:16:32All right. So now what example we can
8:16:34take from our setup. Now here you can
8:16:37see that consider we have our post table
8:16:39over here.
8:16:43So this is our post table. This is our
8:16:46left table. Okay.
8:16:49So I'm going to take this one as a left
8:16:51table.
8:16:53And let's take our comments table and
8:16:56this I'm going to take as a right table.
8:16:58So this is my right table. So this post
8:17:01uh this comments. Okay. And why we are
8:17:04taking this? Because
8:17:06every post can have comments or can't
8:17:09have. So it's a possibility. So that
8:17:12mean simply telling that because not
8:17:15every post is going to have comments.
8:17:16You're getting what I'm talking about.
8:17:18So not every post is going to have
8:17:21comments. Let's say some post some post
8:17:27will have 100 comments
8:17:33and some
8:17:35will have zero.
8:17:38You're getting. So now we'll be able to
8:17:40see that how left chain is going to show
8:17:42the difference very very clearly. So now
8:17:45what we going to do right let's write
8:17:47one. So what we we will do we'll write a
8:17:49query which is going to show all our
8:17:51post including the post that do not have
8:17:55any comments or don't have any comments.
8:17:57Okay. So see how we are going to do
8:17:59that. So I'm going to do select and here
8:18:01I'm just going to render the post dot
8:18:03title and I'm going to take allis and
8:18:05I'm just going to do post title comma
8:18:09and also I'm going to take this com uh
8:18:11comments is going to have the body right
8:18:13so I'm just going to do comments dot
8:18:16body comments is spelling is wrong dot
8:18:20body as comment_body
8:18:24now we are going to do a from so from my
8:18:27post table this is my left table and now
8:18:30we don't have to do inner join you have
8:18:31to do a left join
8:18:34left join will be right side table so
8:18:36which is your commands table okay and
8:18:39then I'm just simply going to give a
8:18:40check condition matching condition why
8:18:42because there is a match right because
8:18:44this post do ID is similar to this post
8:18:47ID because every comment is going to
8:18:50have that post ID associated right so
8:18:52that mean there is a match so here I can
8:18:54simply check if this post do ID is equal
8:18:57to comment commands dot
8:19:00post ID. So here I'm just going to do
8:19:02comments dot post ID. Okay. And then I'm
8:19:05simply going to do a order by and I'll
8:19:08do posts
8:19:10dot title. So I'm just going to do order
8:19:12by title. So how we are doing this? So
8:19:15simply here left join comments. What
8:19:18this line is simply doing that we try to
8:19:20connect each post with its comments
8:19:23simply. And this is the matching rule.
8:19:26If there is a post that has no comments,
8:19:29what it's going to do? The comment body
8:19:31will be what? This comment body null.
8:19:34This is what I mentioned, right? If
8:19:35there is a no matching, so it's return
8:19:36null. You're getting what I'm talking
8:19:39about. And left join is going to keep
8:19:41all our post. Inner join, what it's
8:19:44going to do, right? It's going to hide
8:19:45the post that have no comments. There is
8:19:47a huge difference, big difference. Left
8:19:50join is going to keep all our post, but
8:19:52it's going to return the comment body as
8:19:54null. Inner journey is going to hide the
8:19:56post that don't have any commands. So
8:19:58here you can simply see this right? You
8:20:00can run it and see what is happening
8:20:02here.
8:20:04See so now we have back end API with
8:20:07posgress. Please add more example
8:20:09indexes for beginner. We don't have
8:20:10anything posgress explained. This is the
8:20:12commenter. Now if you go here where we
8:20:14have see added the data go below.
8:20:19So you can see that for posgress join
8:20:22explain we have very clear explanation
8:20:24this is the command please add more
8:20:26example uh sorry no backend uh APIs with
8:20:30posgress for this one we have please add
8:20:31more example but for indexes for
8:20:34beginner this is another one for this
8:20:36particular post we don't have any
8:20:38comment so that means right side there
8:20:40is no match so what's is going to return
8:20:42it's going to return null so that's why
8:20:44you're not getting anything see simple
8:20:46right or not simple but it's clear if
8:20:48you're a beginner It will be a little
8:20:50tricky but see with this explanation I
8:20:52hope you are able to understand what
8:20:53we're talking about. This is the
8:20:54important part. The left journey is
8:20:56going to always keep all the data from
8:20:58the left table. Right uh table has
8:21:01matching data then only it will render
8:21:02or else it's going to return null. So
8:21:04this is the concept of left join. Okay.
8:21:07So we have completed inner join and left
8:21:09join. Let's create the next file which
8:21:11will be many to many relationship. So do
8:21:14many to many
8:21:19relationships.
8:21:23So let's do this one in the next part.
8:21:25All right. So now let's move on to the
8:21:26next one which will be now man to many
8:21:28relationship. Right. So from our example
8:21:30what will be the best uh way to explain
8:21:33this one. So I think this part we have
8:21:35already discussed and that is that in
8:21:36our case right where we have added the
8:21:38data that the many to many means one
8:21:42post can have multiple tags. You
8:21:43remember we have the tags uh this one
8:21:46right I already mentioned that let's say
8:21:47you have one particular tag this can
8:21:49have uh sorry one particular post and
8:21:51that can have multiple tags. Let's say
8:21:53HTML is a tag, CSS is a tag, ReactJS is
8:21:56a tag and one tag can belong to many
8:21:59post. So that means this reacts tag can
8:22:02be uh associated with multiple post. So
8:22:06this will be a proper many to many uh
8:22:09relationship example. So that means one
8:22:11post
8:22:13can have multiple uh tags and one tag
8:22:19can be associated
8:22:22with multiple posts.
8:22:26I hope this is clear right. So now in
8:22:29this example in our example what
8:22:32actually post is doing so it's store
8:22:33post data tags is going to store uh tag
8:22:37uh tags data and then we have one more
8:22:40post tags. Now this is going to connect
8:22:43both post and tags. So if you see so if
8:22:46you go here right so go to the post so
8:22:48do post do ID this post do ID is similar
8:22:53to this post id that we have in this
8:22:55post tags table. Similarly, this tax do
8:22:59ID is similar to this tags id that we
8:23:01have in this post tags dot tags id in
8:23:04this particular table. So that means
8:23:06here in our case we have a post do ID
8:23:08which is similar. So I'm just writing
8:23:10triple equals which is equal to this
8:23:12post tags
8:23:15dot this post id and similarly you have
8:23:19the tags do ID right? So we do tags do
8:23:21id is again is equal to this post tag
8:23:25dot tag id.
8:23:28All right. So now let's see one simple
8:23:31example. So example will be now your
8:23:32task is that you have to show every post
8:23:36with its tag. So that means show me
8:23:41every post
8:23:44with its tag. So how we can do that? Now
8:23:48let's see. So we'll do select. Now first
8:23:50of all what we need to get so I need to
8:23:52get the see when I wanted to show the
8:23:54post I don't have the post title here
8:23:57right so that means if I want to get the
8:23:58post title I need to query this
8:24:00particular table so that means I need to
8:24:02get this post dot title correct so first
8:24:05I need to do what I need to get posts
8:24:08dot title as let's do this one as post
8:24:13title and then also I need to get the
8:24:16tags name so what I mean by tags name
8:24:18these tags name because you don't have
8:24:20the tax name here. So I need to get the
8:24:22tags doame. So I'm just going to do tags
8:24:25dotname as let's do this one as tag
8:24:27name. Okay. So this will be my tag name
8:24:30and this I'm going to get from my post
8:24:32table. And here what you have to do. So
8:24:35you have to do a inner join because you
8:24:37need to check in both the sides. Right?
8:24:39So I'm just going to do inner join. And
8:24:41also if you go to inner join what I
8:24:43mentioned inner join is going to return
8:24:45only the matching rows from both tables.
8:24:48Okay. There is a difference between
8:24:49inner join and the left join. So this
8:24:51I'm just going to do inner join but
8:24:53inner join you have to do with what you
8:24:56have to do with this post tag this
8:24:58particular uh table. Okay. So I'm going
8:25:01to show you how we are going to do that.
8:25:02So first we need to do what? So I need
8:25:03to get post tag. So I'm doing what? So
8:25:06I'm doing in from this post table with
8:25:09this post tag. Why? Because there is a
8:25:12relation with this post ID. This post ID
8:25:15is equal to this post do ID. So that
8:25:17means what will be my matching criteria
8:25:18here? So I'm going to give here on. So
8:25:21I'll do post do id is equal to post tag
8:25:26post tag dot post ID. You're getting
8:25:29right. So this will be my matching
8:25:30criteria. And this is for the first one.
8:25:33Similarly I also need to get the tags
8:25:36name. So that means I there should be
8:25:38some matching criteria between this
8:25:40table and that this table and that is
8:25:41what tags do id is equal to post tags
8:25:44dot tag ID. So these two are matching.
8:25:47So so that if there is a matching so
8:25:48I'll be able to get the name. So that
8:25:50means again what you need to do again
8:25:52you need to do another inner join here.
8:25:54Now this time this inner join will be
8:25:56not with the post tag. This will be from
8:25:59your tags table. So you have this tags
8:26:02table here. Correct? And now what you're
8:26:04going to do? So you have to do the
8:26:05matching criteria. So what will be
8:26:07matching criteria? So matching criteria
8:26:09will be your post tag. So this will be
8:26:12post tag dot. And now you have what? tag
8:26:15id and this will be equal to what? So
8:26:17this will be equal to your tags do id.
8:26:20You're getting what you're doing. So I'm
8:26:21explaining line by line. So this will be
8:26:23a tags do ID. Okay. And then we are
8:26:25going to do what we are going to do
8:26:27order by. Let's do order by and I'm just
8:26:29going to do here posts
8:26:32dot title,
8:26:35tags dot name. So this is what we need
8:26:38to do. Now I think I don't have to
8:26:41explain here now because I've already
8:26:42explained line by line. Still I'm just
8:26:44going to show you sorry explain one more
8:26:45time that what actually this is doing.
8:26:47So select simply we are going to get
8:26:49this post title and the tag name. Right.
8:26:51So here first of all what we are doing
8:26:53so from the post table we are doing
8:26:55inner join with the post tag table
8:26:56because there is a matching. So in the
8:26:58matching we need to give the matching
8:26:59criteria. So post do ID if there is a
8:27:02match with the post tag dot post ID. So
8:27:04that means there is a matching. So it's
8:27:05going to give me that particular data.
8:27:07Then we going to do inergen with the
8:27:09tags because there is also a matching
8:27:11criteria with the tags do ID with the
8:27:13post tags dot tag ID. So this is going
8:27:15to give me the tags name. This is what
8:27:17we're simply doing here. Now let's run
8:27:19this and let's see what is happening
8:27:20here. Okay. So I'm going to just clear
8:27:22this.
8:27:24Let's copy the name [clears throat]
8:27:33syntax error text name at okay let me
8:27:35see what we doing here.
8:27:38Oh say I always do this mistake going to
8:27:40give comma here. So now let's run one
8:27:43second
8:27:45and you can see that what you're getting
8:27:46you're getting the post title with the
8:27:49tag name. Okay. And now this is very
8:27:51very important concept. Now this is not
8:27:53a simple posgress concept. Okay, this is
8:27:56like I'm going to I'm going to say this
8:27:58will be little bit intermediate side. So
8:28:00you need to know all of these things
8:28:01very very clearly so that it's like you
8:28:03don't have to go to any other resources
8:28:05to see how these things are working. So
8:28:07what I mean by this this many to many
8:28:09one to many inner join left join you
8:28:11have to master all of this if you want
8:28:13to become good like if you want to
8:28:16become uh good developer I will say in
8:28:18writing all these queries okay so this
8:28:20is a very very important concept that we
8:28:22have learned here okay so with this I
8:28:25think that's all for this particular uh
8:28:28uh concept now let's move on to the next
8:28:30one next I think what we can do right
8:28:32let's understand some of the table allis
8:28:35now this is also another important
8:28:36concept concept. So what I'm going to do
8:28:38right, I'm just going to do 07. Let's do
8:28:40this one as table allis now
8:28:45spelling is wrong I think.
8:28:49Okay. So now let's close this. So what
8:28:52actually table allis? Allis I think we
8:28:54have already discussed that allis is
8:28:56going to make your join query shorter
8:28:58and easier to read. Right? So allis is
8:29:02going to
8:29:04make your queries
8:29:08shorter and easier to read. So this is
8:29:12the first thing. So simply I'm telling
8:29:14that okay if I want the title from the
8:29:17post table. So I'm just going to do
8:29:19what? Post.title. This is what we are
8:29:21doing right. What we can do right? No I
8:29:23don't want to write this. Instead I want
8:29:25to write I want to write like this. So
8:29:29instead of this I want to do P.Title.
8:29:31Now this P I need to tell Postgress.
8:29:33Okay this P means I'm actually talking
8:29:36about the post table or let's say want
8:29:38to get the uh what you can do maybe
8:29:40users do.ame instead you want to do what
8:29:44you want to do you do. Right. So these
8:29:48will be your allis.
8:29:50So now let's see how we are going to do
8:29:52that. Now this will be a very simple
8:29:53one. So what we can do right maybe let's
8:29:55say
8:29:57I wanted to select something so I wanted
8:29:59to get my
8:30:01let's go here. So I wanted to get the
8:30:03post title let's say and also post
8:30:05status and maybe let's do username also
8:30:08I'm going to get and also let's go to
8:30:11the comment and also let's say I want to
8:30:12get the comment body. So all these
8:30:15things I wanted to get. So first of all
8:30:16what I will do right I'm just going to
8:30:18ptitle. Now notice one thing we are not
8:30:20doing posts do. And here I'm just going
8:30:23to take a license and I'm just going to
8:30:25do this one as post title. We have to
8:30:27give comma here. Let's I'm just going to
8:30:29give P dot status and also let's take
8:30:31the post views also. So I think we have
8:30:34the views right? So I'm just going to do
8:30:35P dot views. So this is what I'm talking
8:30:37about. So I'll do P dot views.
8:30:41Also let's take the username. So I'm
8:30:43just going to do U dot name as let's do
8:30:46this one as author name. And also I'm
8:30:48going to get the comment body. So I'm
8:30:50just going to do C dot body as comment
8:30:55body. Now this is where you have to do
8:30:59the analysis because till this part your
8:31:02postgrade doesn't know what actually
8:31:04this P.title means. Very very important
8:31:07because there is no table that named
8:31:10exactly as P. So that means when I'm
8:31:12going to do here from ports. So now I'm
8:31:15simply telling that okay this is the
8:31:16table I'm talking about. I need to give
8:31:18a allis here and that allis will be that
8:31:20allis that you are using here. So you're
8:31:22simply telling that okay I'm actually
8:31:24quiring from the post table but I want
8:31:26to rename this post from posts to P so
8:31:30that I don't have to write the post word
8:31:33multiple times as simple as that. And
8:31:34now let's say I wanted to do a inner
8:31:36join here so I need to do inner join uh
8:31:39maybe let's do the user because we also
8:31:41need to get the inner join of that uh
8:31:43sorry we also need to get the username
8:31:45right? So we need to do inner journal on
8:31:46the users table but you have to give
8:31:48another allis as U because you are not
8:31:52using users dotname here you are using u
8:31:55dotname okay so this is one more now
8:31:57what we need to do I think this part
8:31:59already discussed so there will be a
8:32:01relations why because your user do ID
8:32:04will be similar to your post dot user id
8:32:07so that means now what you can do right
8:32:09you don't have to do post do user ID
8:32:11instead you can take only these allises
8:32:13here so you'll do p dot user user id
8:32:15you're getting. So you'll do P dot user
8:32:18id and this will be equal to your user
8:32:20do ID. So user do ID this id. So that
8:32:24means user will now become u. So you you
8:32:26have to do u do ID right and then what I
8:32:30need to do right I also wanted to get
8:32:32the comments. So I'm just going to do a
8:32:33left join and I'll do comments because
8:32:36comments is the commands table that I'm
8:32:38actually quering this one. But now this
8:32:40time I wanted to do allis of C. So
8:32:42comments will be as C and then I'm just
8:32:45going to do here on. So there will be
8:32:48another match. Why? Because comments do
8:32:51id right sorry comments.post id will be
8:32:54equal to your post do ID. So that means
8:32:56here the matching condition will be your
8:32:58p dot id because you are taking the post
8:33:00as p which will be equal to c which is
8:33:04here c for comments and these comments
8:33:06will have the post ID. So this will be
8:33:10c.post ID you're getting? So this will
8:33:12be a matching condition and let's do a
8:33:14order by
8:33:16maybe let's do which one we can do order
8:33:19by
8:33:20let's do p dot views as order by okay so
8:33:23I'm just going to do disk so this is one
8:33:26more query now remember it's this
8:33:28particular concept is not about the
8:33:30query because these all the things we've
8:33:31already discussed this is about how
8:33:33you're writing this allis so here post
8:33:35we are talking as a p or writing as a p
8:33:38user table we are writing as a u
8:33:40commands table we are writing as a See?
8:33:42Okay. So now if I just let's say clear
8:33:44this and let's run it once again
8:33:53and you can see that you're going to get
8:33:55the result. So you're getting post,
8:33:56title, status, views, author name and
8:33:59comment body and this is also in the
8:34:01descending order. But again I already
8:34:03mentioned this is about how we are going
8:34:04to write the allis. Okay. So I think
8:34:07that's all for this particular concept.
8:34:09Now in the next part what we can do what
8:34:11else okay we had to do aggregate also
8:34:13right I already mentioned so let's
8:34:15create one more file here and I'm going
8:34:16to do aggregate
8:34:19functions
8:34:21dossql
8:34:24so now what we are talking about the
8:34:26aggregate function so simply in a simple
8:34:30definition aggregate functions will be
8:34:32it always calculates right so it's
8:34:35always going to calculate or calculate
8:34:38one [snorts] result from many rows. This
8:34:42will be your aggregate function. Now
8:34:45there can be so many aggregate
8:34:46functions. So I'm just going to give
8:34:48some of the examples. So I'll do we have
8:34:49the count. What count is going to do?
8:34:52Count is going to give you the number of
8:34:54rows if I'm not wrong. Then you have
8:34:57something called sum. Sum I think by the
8:34:59name you can understand. This will be
8:35:00total value. Then also you have average.
8:35:04So look average and this will be give
8:35:07the average value.
8:35:12Okay. Then what else? We also have the
8:35:14mean. So this mean will be the smallest
8:35:17value. And then also we have the max
8:35:21which will be maximum value. Okay. Or
8:35:24let's do largest or max value. Okay.
8:35:31All right. Now where where actually you
8:35:34can use all of this very very very
8:35:36helpful and that will be I'm going to
8:35:38give you some real life example for
8:35:40example let's say you're creating some
8:35:41admin dashboard where you have to
8:35:42calculate your sales let's say you're
8:35:44creating some reports you're creating
8:35:46some analytics dashboard there also
8:35:49mostly it will be around your admin
8:35:51panels and those related work and you'll
8:35:53see that you're going to use this one
8:35:54lot of time now let's say I wanted to
8:35:57write a very very simple example that
8:35:59what I wanted to do right I wanted to
8:36:01count all the rows from my post table.
8:36:04Okay. So let's do one by one then I'm
8:36:06going to explain. So I'm just going to
8:36:07do select. Now let's say you want to
8:36:08read all the uh rows from a certain
8:36:12table. Okay. So how you're going to do
8:36:14that? So for now we are only going to
8:36:15use the post table only. To to read all
8:36:18the rows from a certain table you have
8:36:20to use a count here. And this count
8:36:22you're simply going to tell okay this
8:36:23here I'm just going to count everything
8:36:25and this I'm just going to also give
8:36:27allis. So this will be my total
8:36:29underscore
8:36:32posts. Okay. And here what you're going
8:36:35to do. So I'm just going to give a from
8:36:38post table. So I'm simply telling we'll
8:36:40do one by one. Okay. So this is the
8:36:42first one. So it's simply telling that
8:36:43give me or count all the rows from this
8:36:46post table because this is the table
8:36:47that we are using. Now let's run this.
8:36:59Okay. So, you're getting three.
8:37:00Fantastic. Now, now let's say what I
8:37:03need to do, right? I [snorts] wanted to
8:37:05now count what I wanted to give a
8:37:06filter. So, what filter I wanted to
8:37:08give? I wanted to give a filter where
8:37:10the status is published. If I'm not
8:37:12wrong, we have a published status. See,
8:37:14published or dropped. So, I only wanted
8:37:17to count all the rows where the status
8:37:20is published. So that means now you
8:37:22can't directly use count you have to use
8:37:24a filter. So how you can do that? So you
8:37:25have to do count
8:37:28and then you have to use a filter here.
8:37:30Okay. And this filter will be now I
8:37:33think we have already used this one
8:37:34multiple times where keyword status will
8:37:38be equal to what whatever status you
8:37:40wanted to check. So now I wanted to
8:37:41check about the published and then let's
8:37:43give a license and I'm just going to do
8:37:45this one as published
8:37:47posts. So what this is going to give
8:37:50this is going to count all the rows but
8:37:52it's going to apply a filter now. Okay.
8:37:54Now let's run it and let's see what
8:37:56you're getting. So if I go here but
8:37:59telling syntax in the count
8:38:02again I forgot to give comma. Okay. So
8:38:06let's do
8:38:09so you can see that we have three post
8:38:11publish post two. Change this one to
8:38:13dropped and you'll see that you are
8:38:14going to get one because we have only
8:38:16one uh dropped post right. So if I just
8:38:19go here, run it again, you see that we
8:38:22are getting only one. Fantastic.
8:38:24Now let's undo here.
8:38:26Next, what we want to do, we'll give
8:38:29comma here. So now let's say sum. I want
8:38:32to do sum or or what I will do, right?
8:38:35Maybe let's do this one. Go to post.
8:38:38We have these views, right? So I wanted
8:38:40to do a sum of all these views of all
8:38:43rows. You're getting what I'm talking
8:38:45about. So when you're going to do that
8:38:48this very very simple so views is I'm
8:38:50talking about these views I wanted to
8:38:51sum so you have to use sum and then
8:38:53you're going to tell that okay calculate
8:38:55all the sum of what so you have to give
8:38:57here which column so this will be my
8:38:59views column simple and then you're
8:39:01going to give as and let's giveis so
8:39:03this will be my total views okay so that
8:39:06mean now this is going to do what this
8:39:08is going to add all your view counts
8:39:11together from this table okay from this
8:39:14particular table so now if I just run it
8:39:16and you'll see that you're going to get
8:39:18320 and you can also uh like reconfirm.
8:39:21So you have what
8:39:23140 140 + 180 so 320.
8:39:28What else? Let's do the average views
8:39:31also. So for average it will be simple
8:39:32just use average pass the views and
8:39:35you're going to do here average
8:39:38views also to give comma here. Save this
8:39:42and now run again.
8:39:45So this will be your average views. So I
8:39:48think this is done. What else? I think
8:39:50min minimum and maximum let's do that
8:39:51also. So minimum again it will be
8:39:53simple. So do minimum views as lowest
8:39:57views and also you're going to do a
8:40:00maximum. So do max of views as highest
8:40:07views.
8:40:09So this is going to give the minimum and
8:40:11the maximum. So here, let's clear this
8:40:13and run it here again. So we can see
8:40:16that you're going to get the lowest
8:40:17views here. So let me just do one thing.
8:40:20I'm just going to remove some of these
8:40:22here. Let's comment it out
8:40:26this this.
8:40:32Okay. So you have the lowest views which
8:40:34is 40 and highest view which is 180. So
8:40:37you can go here and can confirm 40 and
8:40:40180. Okay. So with this I think we have
8:40:42covered the many to many table analysis
8:40:44aggregate. Now let's move to the next
8:40:46one. So let's understand group by having
8:40:48count disting and some of the basics of
8:40:50indexes. Okay. Okay. So moving to the
8:40:52next one which will be group by. Okay.
8:40:55So let's create a group by dossql file.
8:40:58So what actually group by is right. So
8:41:00in simple way to explain group by will
8:41:03be or group by creates
8:41:06groups
8:41:08of rows. Okay. In the previous section
8:41:11we discussed aggregate function right
8:41:13count sum average mean max all these.
8:41:16Now let's say what we are going to do
8:41:18right these uh functions calculates
8:41:21values inside each group right. So here
8:41:24what we are going to understand in this
8:41:26particular section in the previous
8:41:27multiple times we have used something
8:41:29called where. So where actually do what
8:41:33where actually filters very very
8:41:35important normal rows before grouping.
8:41:40Okay. So this will be where keyword I'm
8:41:43just talking about I'm just telling
8:41:45keyword only so that you can understand
8:41:46where actually filters normal rows
8:41:49before grouping what having will do
8:41:53having filters right we have having
8:41:55filters. So having filters groups
8:41:59after grouping now this might be a
8:42:02little tricky until unless we are going
8:42:03to understand the concept. Okay. Now
8:42:06when you're going to use having so
8:42:08you're going to use having when the
8:42:10condition is going to depend or
8:42:12condition depends on a aggregate
8:42:13function.
8:42:15So now the best option will be I've
8:42:17already created one proper example for
8:42:20this that you have to find the authors.
8:42:23Okay. So to find the authors who have
8:42:27written
8:42:29at least two posts. Okay. So you have to
8:42:33find the authors who have written at
8:42:35least two post. Okay. Now here you also
8:42:38have to do what? You have to use some
8:42:40kind of aggregate functions. Correct?
8:42:42Because you have to get the count right
8:42:44count sorry count of the post. So let's
8:42:47how we can do that. So I'm going to do
8:42:50select. Now first of all when I'm
8:42:52talking about find authors so that means
8:42:54what I need to get what the author name
8:42:57so what actually author name so author
8:42:58name here is either this is Anona or
8:43:00Rahul so author name is nothing but your
8:43:03username right so this is where so what
8:43:05I'm going to do I'm just going to do eu
8:43:07dot name as author name
8:43:12comma and now what I need to do I
8:43:14already mentioned that we need to have
8:43:16the count why because we need to see who
8:43:18written at least two post so that means
8:43:20I need to use aggregate function here
8:43:23and how I can see that whether this
8:43:25particular author already created two
8:43:27post or not and that is from this post
8:43:31id. So we have this post id right. So
8:43:33I'm just going to do here p do id as
8:43:37total
8:43:38posts and now what I need to do right
8:43:41I'll also give you the sum and let's do
8:43:44the p dot views as total views.
8:43:49Okay. So now first of all we need to get
8:43:51the table. So first table will be my
8:43:53user table because I need to get the
8:43:55username. So I'm just going to do user.
8:43:57But very very important whenever you're
8:43:59going to use the table allis you have to
8:44:01use allis here or else I already
8:44:03mentioned that posgress will not be able
8:44:05to understand that this U means the user
8:44:08table. Okay. And then what we need to do
8:44:10right we need to do a left join. So I'll
8:44:13do left join with the post table as P
8:44:16because we're using the P here. Okay. So
8:44:18this will be small P where so here what
8:44:22will be the matching condition multiple
8:44:23times I will discuss because your U do
8:44:26ID user do ID similar to your post dot
8:44:29user id so that means here I'm just
8:44:31going to do u do id will be equal to p
8:44:34dot user id correct so this will be my
8:44:37matching condition and now here what I'm
8:44:39going to do right I'm just going to do a
8:44:40group by
8:44:42u do ID and let's do a uh what else we
8:44:45going to do maybe let's do u dot name
8:44:47Okay. User do ID user dot name. Now what
8:44:50I mentioned here, so let's go here. What
8:44:53I mentioned having filters groups after
8:44:55grouping filter normal rows before
8:44:57grouping. So now we need to use a having
8:45:00because we already have done the already
8:45:02used the grouping. So here what you have
8:45:05to do you have to use having. So this
8:45:06having is simply going to tell that okay
8:45:08now I need to see if the count of that
8:45:11post. So count of p dot id is greater
8:45:14than or equal to two or not because that
8:45:16is my criteria here that that user at
8:45:18least have written two post. So that
8:45:20means now I'm going to see having count
8:45:23dot count of p do ID should be greater
8:45:25than or equal to two simple and then I'm
8:45:28also going to do order by simply and
8:45:30let's do order by of total post.
8:45:34Let's do this one as descending order.
8:45:36So now let's see what actually this is
8:45:38doing. So first of all we have got from
8:45:39user as you start with the user table
8:45:43left join post sp means connect each
8:45:46user with their post. What actually this
8:45:49group by is doing now? So this group by
8:45:52I already mentioned this group by is
8:45:53going to create one group for each user.
8:45:57So group by creates group of rows. So
8:45:59this group by is going to do what is
8:46:01going to create a group of each user.
8:46:04Why? Now you might ask me okay why it
8:46:06will create? So whatever post let's say
8:46:09we have two users Anona and Rahul. So
8:46:12all post written by Anunna become one
8:46:14group and all post written by Rahul
8:46:17become another group. Okay. So this is
8:46:20very very important. So this is this
8:46:22line is actually doing that. So it's
8:46:24going to create one group for each user.
8:46:26Count is going to do what? So it's
8:46:28simply going to check the count that how
8:46:31many post exist inside each user group.
8:46:35Right? This what I'm talking about. Then
8:46:36we have the sum. Sum is going to give
8:46:38you the sum. And this having what
8:46:40actually having is doing? Now this is a
8:46:42criteria. This is simply telling that
8:46:44keep only those user group where the
8:46:48post count is greater than or equal to
8:46:50two. You're getting so first we are
8:46:53using group by then we are using having
8:46:55very very important that is the reason I
8:46:57mentioned that having filter groups
8:46:59after grouping. So first we created the
8:47:01group and then we simply telling and
8:47:03sorry first we have created the group
8:47:05then we counted all the post then we
8:47:08created the sum also then we created one
8:47:10group for ana one group for Rahul and
8:47:13now I'm doing what now I'm doing the
8:47:15filtering on that count that you are
8:47:17going to only keep those user group
8:47:20where the count is more than two you're
8:47:23getting so if the count is less so it's
8:47:25not going to give you that result and
8:47:26then you're simply doing a order by so
8:47:28now let's run this and see what you're
8:47:30getting. Okay,
8:47:33that's it. So now you're getting Anunna
8:47:36total post is two and total views is
8:47:40140. Why? Because Anunna created two
8:47:42post as much as I remember I added. Let
8:47:46me just check. Okay, see this one right?
8:47:51So this is how you need to do. Let's say
8:47:52you want to do that. Okay, I wanted to
8:47:54check whe the count is exactly equal to
8:47:56one. So now if you run this, what will
8:47:58happen?
8:48:00So you're going to get Rahul because
8:48:01Rahul created only one post. So this is
8:48:04how you have to use group by and having.
8:48:07Okay. So [snorts] I think that's all for
8:48:10this particular one. Let's do one more
8:48:12uh concept here which is also important
8:48:14and that is count distinct. This will
8:48:16not take much time but let's do this and
8:48:19I'll do SQL. So what this count distinct
8:48:22is going to do right. So this is going
8:48:24to count unique values right? So it's
8:48:26going to count
8:48:28unique values. So what I mean by this?
8:48:32Okay. Now first of all also another
8:48:35thing I need to mention and that is when
8:48:37this is useful. Now let's say you're
8:48:39using some joints, right? And this is
8:48:41useful when joins create repeated rows.
8:48:44Now example will be okay let me think.
8:48:46So okay so let's say you have one post
8:48:49right? I already mentioned that one post
8:48:50is going to have multiple tags right?
8:48:52You have one post. That post has ReactJS
8:48:54tag, NexJS tag, SQL tag, DB tag, HTML
8:48:57tag. Now when you're going to join this
8:49:01post with post tags and the tags table
8:49:04that we have, the same post can appear
8:49:07multiple times, right? It's possible. So
8:49:09this is where what we going to do,
8:49:11right? We are going to use something
8:49:12called count distinct and the property
8:49:14which is going to count only the unique
8:49:16post. So the best example will be let's
8:49:19say I wanted to count how many
8:49:22unique post sorry how many unique posts
8:49:26are connected
8:49:28to each tag very good example that how
8:49:32many unique post are connected to each
8:49:34tag this is what I wanted to uh see now
8:49:38let's we are going to do that if you
8:49:40notice that whenever we are going to
8:49:41write this particular uh query right
8:49:43you'll notice that how many previous
8:49:45concept we are applying here. So what I
8:49:47mean by this? So previously we have
8:49:48understood the concept of select, the
8:49:50concept of allis, the concept of left
8:49:53joint, concept of inner joint, concept
8:49:55of group by order by. So basically what
8:49:57I'm telling that the mode we are
8:49:59progressing in this particular video,
8:50:00the mode we are applying the previous
8:50:01concept. So here for example what I need
8:50:04to get I need to get the tag. So first
8:50:06I'm just going to get the tag name. So
8:50:08I'm just going to do this one as tag
8:50:10name. Next give comma. And now what I'm
8:50:13going to do right I need to count how
8:50:14many unique post how many unique post
8:50:16I'm going to give count and here you
8:50:18have to give distinct
8:50:21okay distinct p dot id okay so post do
8:50:24ID as total
8:50:28unique
8:50:31posts and now what I'm going to do first
8:50:34of all what I need to get I need to get
8:50:35the tags table so tag the allies as I've
8:50:38given t so this will be as t and then we
8:50:40are going to do a left join
8:50:42So I'm going to do a left join with my
8:50:44post tags table because there is a
8:50:47relations with the post tag table also.
8:50:49So here I'm just going to take this one
8:50:51as let's do post tag. So PT and then I'm
8:50:54simply oh sorry PT.
8:50:57Then I'm simply going to check the
8:50:58matching condition that the tag do ID
8:51:01should be equal to PT which is the post
8:51:04tag dot tag ID because there is a
8:51:06matching here right? So your post tag
8:51:08has the tag id which is similar to this
8:51:10tags do id correct. So I'm simply going
8:51:13to do this t dot id which is tag do id
8:51:16is equal to post tag dot tag id. Okay so
8:51:19this is the first one. Then [snorts] I'm
8:51:21going to give another left join and this
8:51:24left join will be on my post as p. This
8:51:27is what I have given here p. And here
8:51:29also you do the same logic. So now this
8:51:32time this will become t dot id will be
8:51:35your what? Sorry, let's do PT dot PT dot
8:51:40post ID. I think PT do.post ID this one.
8:51:43So PT dot post ID will be equal to P do
8:51:45ID and now I'm going to do a group by.
8:51:49So do group by T dot id tag ID and P dot
8:51:53name. And maybe let's do a order by
8:51:56also. So I'll do order by total unique
8:51:59post in descending order.
8:52:03the main part that we are simply doing
8:52:05for this particular section which is
8:52:07this one. So we're simply getting the
8:52:09unique post that are connected to each
8:52:11tag. Now you might be thinking okay how
8:52:13I'm writing all of this. Believe me I've
8:52:15written all of this so many times
8:52:17previously. So for me it will be easy
8:52:19for you. It can can be difficult if
8:52:21you're a beginner if you're a student if
8:52:23you're very less experienced. You need
8:52:25to do lot of practice. These things will
8:52:27not come very easily. You can be very
8:52:29honest that how where you have to apply
8:52:30lab join where you're going to apply
8:52:32group by where you going to apply having
8:52:35okay these thing where you're going to
8:52:37use where so you need to do a lot of
8:52:39practice but this is exactly what this
8:52:41query is doing see whenever you're going
8:52:43to work with relationships right you
8:52:45have to see the table that what actually
8:52:47your table structure is and what are the
8:52:49properties in two tables that are
8:52:52connected with each other for example
8:52:54tag ID is similar to your tag ID here
8:52:57post ID for this table is similar to
8:52:59your post do ID. So this is what I'm
8:53:01talking about. So now let's run this. If
8:53:04I run here, right? So let's see what
8:53:05you're getting
8:53:12and you're going to get the unique post
8:53:14that how many tag. So this SQL is
8:53:16associated with two unique post back end
8:53:19is associated with one post. And if you
8:53:22want we can also verify. So let's see
8:53:24what we are getting here.
8:53:30we have SQL two times and back end one
8:53:34time. All right. So that means this is
8:53:36working fine. So with this I think we
8:53:38have covered the group by and also count
8:53:41distinct. So now let's move on to the
8:53:43next one. All right. So moving to the
8:53:44next one. Let's understand another very
8:53:46very interesting concept and that is
8:53:47called sub queries. Okay.
8:53:52SQL. So let's see what actually this is
8:53:54right. So I'll do sub queries
8:53:57in post posgress.
8:54:03Let me refresh this
8:54:08in postgress
8:54:14queries [snorts]
8:54:15nested inside another SQL statement.
8:54:18Okay. All right. So I just wanted to
8:54:19show you because I'm going to explain
8:54:21this one in a very simple way. So what
8:54:23[snorts] I mean by this? So this is
8:54:25simply we are running one query inside
8:54:27another query. So we are running one
8:54:30query inside another query as simple as
8:54:33that. Okay. So what postgress is going
8:54:36to do? Postgress is going to run the
8:54:38inner query first. So I'll do runs
8:54:42the inner query
8:54:45first and then it's going to run the
8:54:47outer query. Okay. So it's going to run
8:54:49the outer query. All right. So now let's
8:54:53understand this one in a uh simple
8:54:55example. So your task is what we need to
8:54:57do right maybe let's do one thing that
8:55:00first we are going to have two queries.
8:55:02Okay in the inner query we are going to
8:55:05calculate some average values and that
8:55:08value your outer query is going to use.
8:55:11So that means when your inner query is
8:55:13going to return sorry calculate
8:55:15something right it it's I'm just giving
8:55:17as part of this example because we are
8:55:19using this file as our data source. But
8:55:22for your project it can be anything. So
8:55:24for this one I'm just doing right let's
8:55:25say I'm going to calculate my average
8:55:27views and that average views I wanted to
8:55:29return. So that is going to return some
8:55:31value and that value I'm going to use in
8:55:33my outer query. So that will be two
8:55:35query. Okay. So let's how we are going
8:55:37to do that. So now uh okay what will be
8:55:41the question? The question will be maybe
8:55:42let's do this one in this way that which
8:55:44post are perform performing better than
8:55:50average
8:55:52something like this. So here how I can
8:55:55do that right. So I'm just going to do
8:55:56select so give me the title of that post
8:55:59comma give me the status of that post
8:56:01and also give me the views but this one
8:56:04you wanted to give me from my post
8:56:06table.
8:56:08Now here what I'm going to do where
8:56:11the views now we have our inner query.
8:56:15So where the views is what? So views is
8:56:18greater than the average value. So that
8:56:21means here now I'm going to write my
8:56:22inner query. So now I'm just going to do
8:56:24a select. So how you can calculate
8:56:27average views. What thing you have to
8:56:29use here? Means what are the things you
8:56:30have learned so far? So to calculate
8:56:32average views you have to use aggregate
8:56:34function. Right? So what will be my
8:56:35aggregate function? I have to do is
8:56:36average. So average will be on what on
8:56:39views and then you have to give what? So
8:56:41from where you have to do this from your
8:56:43post table. So now this is your inner
8:56:46query. So this is going to give you the
8:56:48average views. This is going to return
8:56:50the data and then you're going to use or
8:56:53run this outer query. So that means
8:56:55you're simply telling select title
8:56:57status views from post where views is
8:57:00greater than 100. Sorry views is greater
8:57:02than 20. So why I'm talking about this?
8:57:04So consider this particular query result
8:57:07is this particular query's result is 20
8:57:11right so this
8:57:13block is going to return 20 so it will
8:57:16become this so that means I'm simply
8:57:17telling that where the views is greater
8:57:19than 20 you're getting so this is about
8:57:21the subqueries and then you can also do
8:57:24order by so do order by views
8:57:30and then I'm going to do descending
8:57:32order so if you save this and run this
8:57:35it's going to work. So let's run it
8:57:37again.
8:57:39Okay. So this is what you're getting
8:57:42right. But the point is you have to
8:57:43understand this one that how you're
8:57:44running queries. And you can also see
8:57:46some example. Give me one example.
8:57:49See what it's telling here.
8:57:54Select name query where the price is
8:57:56select average price from products. This
8:57:58is almost the same example but this is
8:58:00also doing the same thing. This is a
8:58:01subquery, right? This is one subquery.
8:58:04The point you have to understand that
8:58:05it's going to run the subquery first.
8:58:07It's going to return the result and then
8:58:10the outer query is going to use that
8:58:12result. Okay. So I think that's all for
8:58:15this particular concept. I think we
8:58:17don't have much here. Now also I thought
8:58:20that I'm not going to explain or cover
8:58:22the indexes but let's give you some idea
8:58:24so that if this I already mentioned if
8:58:26the video this video will do good I'm
8:58:28going to create anyway one more uh part
8:58:32two for this particular video but that
8:58:35will happen only if this one will do
8:58:36good. Okay. So I'm going to cover some
8:58:38of the very advanced level of database
8:58:40concept that you have to pay to watch
8:58:42those courses. Okay. So I'm going to do
8:58:44this one for free. So all right. So
8:58:46first of all let's understand what are
8:58:47indexes. Okay simply indexes help you or
8:58:51indexes helps not me indexes helps
8:58:53postgress find rows faster. So I'm just
8:58:56going to do index helps postgress
8:59:01find rows faster. This will be the best
8:59:05example. What will happen without an
8:59:07index? Now let's say you have 1,000
8:59:10data. You have to find something. So
8:59:12without if there is no index posgress is
8:59:14going to scan many rows to find your
8:59:17matching data with an index what it
8:59:20usually do right it's going to jump
8:59:22closer to the data it needs so how what
8:59:25will be the uh how to frame mental model
8:59:30consider there is a book now you have a
8:59:32book index right so book index means
8:59:34number what that will help you so that
8:59:37is going to help you find a particular
8:59:38topic without reading every page. This
8:59:42is the best example, correct? Similarly,
8:59:45if you have a database index, it's going
8:59:47to find rows without checking every
8:59:49data. So, I'm going to repeat once again
8:59:52your book index, right? Book will always
8:59:54have the index, right? In the first
8:59:55page, let's say you have some indexes,
8:59:57you can go to a certain page. Similarly,
9:00:00in posgress or any DB, if you have
9:00:02indexes or database index is going to
9:00:04help find rows without checking every
9:00:08row. So, that means what? It's going to
9:00:10do what? It's going to speed up your
9:00:12query reading process. For example,
9:00:15let's say your query reading process is
9:00:16select, right? So, it's going to speed
9:00:19it up this process. This particular
9:00:22process, right? So, I do this particular
9:00:25process.
9:00:27So, now uh what I will do right maybe
9:00:30let's do one thing. So, first I will
9:00:33just see my data. So, I'm just going to
9:00:36select let's take the ID. I'll do a
9:00:38title. Let's do a status. I'm going to
9:00:41do a views and also we have the user ID.
9:00:45Correct. And I'm just going to do this
9:00:46one from posts. So this is my post table
9:00:51data. Correct? So now I have one
9:00:54requirement that I need to filter the
9:00:55post by status. So something like this,
9:00:58right? So you have / posts and then
9:01:00you're going to do status equal to
9:01:04published.
9:01:05Correct? So this is one filter. So here
9:01:08how you can do that. So what we'll do
9:01:10select give me ID give me my title give
9:01:14me my status and here I'm just going to
9:01:18do from posts table and then I'm simply
9:01:20going to do where the status is equal to
9:01:23published correct. So status will be
9:01:26published.
9:01:29So this will be my query. Simple.
9:01:32So now the problem will occur when this
9:01:35post table will become very large. So it
9:01:38always needs to do what posgress needs
9:01:40to find each and every rows to find this
9:01:42particular uh criteria here that okay
9:01:46give me these many post maybe there are
9:01:48500 post where it is the status is
9:01:50published. Now this is where what we can
9:01:53do right we can create a index. So let's
9:01:56how we are going to do that. So first
9:01:57I'm going to do create. So to create
9:01:59index you have to do index again. First
9:02:01you have to check that if not exist.
9:02:05Okay. And let's give this one as idx
9:02:10posts. And now see because we need to
9:02:12write index for this status column. So
9:02:14I'm just giving this one as underscore
9:02:16status. Okay. And what you have to do
9:02:19you have to give on post and you have to
9:02:22tell that okay which column you want to
9:02:24do. So we want to do on the status
9:02:26column. So now this is actually very
9:02:28important. Okay. And you'll see that any
9:02:30if you are working in a company or let's
9:02:31say any open source you'll see that they
9:02:33try to use this particular structure and
9:02:35this is the naming style. Now what this
9:02:38idx means this is index this is the
9:02:40table name and this is the column name
9:02:42very very important. Okay. So this will
9:02:44be very important. So here
9:02:49idx is simply telling this is the id or
9:02:53maybe this is the index.
9:02:55posts simply telling this is the table
9:02:57name and status
9:03:01will be your what column name
9:03:04okay so now what we are going to do
9:03:07right so let's say we want to now filter
9:03:12and sort together so now I wanted to
9:03:15write a query that is going to maybe
9:03:17let's do something like this it's going
9:03:18to find the publish post also at the
9:03:21same time it's going to show you the
9:03:22most viewed post first. Okay. So
9:03:26something like this. Now here I want to
9:03:28do very very important. Okay. See what
9:03:29you're doing. So I'm just going to do
9:03:30here title. Give me title. Give me my
9:03:33status and give me the views from which
9:03:36table. So from posts
9:03:39table. I'm just going to do where. So we
9:03:42already using status is equal to list
9:03:48and I'm just going to do order by and
9:03:50I'll do on views and descending order.
9:03:54Now here this query although it's may
9:03:57look very simple it's easy to understand
9:03:59but it has two important parts okay and
9:04:01this part we haven't discussed before
9:04:03this where status equal to publish right
9:04:06this is going to do what it's going to
9:04:07filter by status and order by views
9:04:10descending it's going to do what it's
9:04:12going to sort by views from highest to
9:04:13lowest
9:04:15okay now here what we can do right now
9:04:18let's say I again I'm just talking about
9:04:20various way of writing indexes only for
9:04:22now so this is one way now here this is
9:04:25a composite thing we are doing so we are
9:04:27doing two things you getting what I'm
9:04:29talking about so that means we are using
9:04:32what we are doing two things together so
9:04:35that means this is a concept of a
9:04:37composite index so we are doing we are
9:04:39first filtering and also we doing a
9:04:41order by so this will be a composite
9:04:45composite index so how you can create
9:04:48the index so you can create the index
9:04:50like this so you're going to do create
9:04:51index
9:04:53if not exist now I'm just going to do
9:04:56see idx for index post will be my table
9:05:00status is one of the column that I'm
9:05:02doing and then also I have a views
9:05:04column and then what you have to do you
9:05:06have to do on posts because that is the
9:05:08table name and now you have to give what
9:05:10you have to give status and you have to
9:05:13give views in descending order so this
9:05:15is one of your index you're getting what
9:05:18I'm talking about so this is how you can
9:05:20write a composite index index. Okay. So
9:05:23now maybe let's do one thing. I'll give
9:05:26you some little intermediate level of
9:05:28concept or how we can write indexes on
9:05:30foreign key columns. Now we already have
9:05:33discussed the concept of foreign key.
9:05:34Right? For example, let's say if I go
9:05:37here, your post dot user id is
9:05:39referencing the user do ID. This one,
9:05:41right? So means every post is belong to
9:05:44a valid user. Correct? Now this is the
9:05:47concept about this is a concept of
9:05:49foreign keys. So something like this.
9:05:50Let's say you have one get request
9:05:54users and then I'm just going to do id
9:05:58and then give me posts.
9:06:00So that means your back end needs to
9:06:02find all post written by one particular
9:06:05user. You're getting all these things
9:06:06what I'm talking about very very
9:06:07important thing. So that mean this is
9:06:09this is a very valid scenario right
9:06:11let's say you are creating one
9:06:12particular user profile where you need
9:06:14to render all the post that is written
9:06:16by that particular user. So that means
9:06:18how you can do that. So you have to do
9:06:20like this right? So we're going to do
9:06:21select and give me title, give me
9:06:25status, give me views.
9:06:28Now what I have to do first from posts
9:06:31because this is the table and then what
9:06:34I'm going to do here I'm just going to
9:06:35do where user ID is equal to. So I'm
9:06:38going to write inner query here. User ID
9:06:40is going to what? Select ID from where?
9:06:44from users table and then I'm simply
9:06:48going to do okay give me where name is
9:06:51equal to anona now this anona name is
9:06:53can be dynamic value because you're not
9:06:55going to write a hardcoded value but
9:06:57this name will be this id that you are
9:07:00getting correct so this will be let's
9:07:02say this can be also rahul I'm just
9:07:03giving one example
9:07:06now here how you can write a index for
9:07:09this here if you notice a post do user
9:07:12id actually using to find post for a
9:07:15particular user. So that is the reason
9:07:17this will be good column that to write a
9:07:20index. So that means if I want to do
9:07:22write index for this so I'm just going
9:07:24to do create index
9:07:27if not
9:07:29if not exist
9:07:32and here I'm do again same format I'll
9:07:34do id sorry idx post is the table name
9:07:37and I'm just going to do user ID because
9:07:40this is what we're doing and this will
9:07:41be on post table and what will be your
9:07:44property your property will be on user
9:07:46id because this is a foreign key
9:07:47relations right so this is how you can
9:07:50yet. So I think we have covered most of
9:07:52the things and this now here we don't
9:07:54have anything that much to run but this
9:07:56is how you can write indexes. The point
9:07:58is you can't write indexes blindly. You
9:08:01have to see the requirement that where
9:08:03you are going to write but the format
9:08:04has to be very important and it is also
9:08:06very very easier to understand also that
9:08:08why you writing all this. Okay. So with
9:08:11this I think we have almost covered all
9:08:13the things. Let me just think that what
9:08:14else we can cover that we going to cover
9:08:16in the next part and with that we'll end
9:08:18this particular video. So let's move on
9:08:20to the next one. All right. So let's end
9:08:21this particular video with transactions
9:08:24although I'm thought that I'm not going
9:08:25to cover but let's uh let me give you
9:08:27some of the very little glimpse what
9:08:29actually it is because it's very
9:08:31important concept and [snorts] then if
9:08:33I'm creating any next but uh anytime
9:08:35soon then I'll be also covering this one
9:08:37later. So this will be transactions.
9:08:41Okay. So what actually transaction does
9:08:44is it lets you uh multiple or it give
9:08:49you the opportunity to run multiple.
9:08:54So do multiple
9:08:57SQL statements
9:09:00run as one safe
9:09:05unit. Okay. So simply we are telling
9:09:10that whatever we are running either all
9:09:12thing or everything is going to succeed
9:09:15or everything will be cancelled.
9:09:18So now
9:09:19okay this where this will be very very
9:09:22helpful. Now this is very very helpful.
9:09:24Let's say we're creating an e-commerce
9:09:26website where user is placing an order
9:09:29at the same time when you're placing an
9:09:30order right. So what are the things
9:09:32you're going to do? So you place a order
9:09:34at the same time if the order is
9:09:36successful you need to reduce the stock
9:09:38count of that particular product right.
9:09:40So reduce the stock of that product. So
9:09:44this is also comes under transaction. At
9:09:46the same time you need to do creating
9:09:48payment records,
9:09:52transferring money,
9:09:55right? Also you need to do what? You
9:09:58need to also do creating user
9:10:02records
9:10:03with related profile data. All right. So
9:10:09that means what what actually we are
9:10:11doing here if I if I ask you to sum up
9:10:14in one single sentence. So this is
9:10:16simply we are using a transaction where
9:10:17multiple database changes must succeed
9:10:20together. So we have to do all these
9:10:22things. Okay. So now let's see how we
9:10:25are going to do this uh in our example.
9:10:28So now first of all what we need to do
9:10:30right how we are going to start a
9:10:32transaction. So that is the first thing
9:10:33you have to understand. So first
9:10:35whenever you're going to start a
9:10:36transaction you have to do begin. So
9:10:39begin is going to start a transaction.
9:10:41Now what will happen right once you
9:10:44write begin postgress is not going to
9:10:46save the changes permanently until
9:10:49unless we are going to do something
9:10:50called commit. So that we are going to
9:10:52discuss later. Now let's say we start a
9:10:54transaction. Now in the first step what
9:10:56we wanted to do right we wanted to
9:10:58update our draft post. So we have a
9:11:00draft post right you search here we have
9:11:02a draft post correct. So which one is
9:11:07that? This is the draft one. Correct. So
9:11:08this is a draft post. So here we have
9:11:11what indexes for uh beginner. This is
9:11:15the title. Maybe let's do one thing.
9:11:17Let's change the status from draft to
9:11:19published. So this will be my first
9:11:21change. So I'm just going to do update.
9:11:23So update my post table. Set the status
9:11:28to published
9:11:33where title is equal to what?
9:11:37This one title is indexes for beginner
9:11:41correct and then I'm also going to give
9:11:43a and because see there can be two title
9:11:46also with the same so you always have to
9:11:48give status is draft so these small
9:11:51small things you have to understand so
9:11:52this is the first thing that we are
9:11:53doing what you're doing right now in the
9:11:56step two this is not the transaction is
9:11:58not yet completed I wanted to increase
9:12:00the views for the same post okay so
9:12:03let's say how many views I have 40 so
9:12:05now I wanted to increase the views of
9:12:07this post. So again, I'm just going to
9:12:08do update posts
9:12:11set views equal to views + 50 where
9:12:18title is equal to indexes for beginners.
9:12:24Okay, so this is the third one and then
9:12:27what I'll do right maybe let's do I want
9:12:30to check the result that if this is done
9:12:31or not. So I'm just going to do give me
9:12:33the title, give me the status, give me
9:12:36the views
9:12:38from posts table where title is equal to
9:12:43indexes for beginners.
9:12:46Okay. And then at the end what you have
9:12:49to do as I already mentioned very very
9:12:50important you have to do commit. So what
9:12:53commit is going to do? Commit is going
9:12:54to permanently save all these changes
9:12:56inside the transaction because this is
9:12:58whatever we are doing this is a
9:12:59transaction. Okay. Now there is a
9:13:02concept called roll back also, right?
9:13:04Roll back is going to cancel all the
9:13:05changes. But for now, if you're
9:13:07understanding this thing, it is more
9:13:08than enough. Okay. So now let's run this
9:13:11first and see what is happening here.
9:13:14Run again. I'm doing some mistakement.
9:13:17Update post.
9:13:22I'm reading update post. Something we
9:13:24doing wrong. Let me just check.
9:13:27There might be some places I haven't
9:13:29given. Okay, this is where I have to
9:13:31give this.
9:13:35Okay, so let's run again and you can see
9:13:37that we do begin update one update one.
9:13:39This is the result. This is now publish
9:13:41the PUS are also changed and this is
9:13:42commit. Okay, why you're seeing for 140?
9:13:46Because the previous time also we have
9:13:47already updated one time. That's the
9:13:48reason. But you can see that from begin
9:13:50to commit this transaction is now
9:13:52completed. So overall you have to
9:13:54understand the concept that what you're
9:13:55doing when we are doing multiple DB
9:13:56queries at the same time transactions
9:13:59are extremely helpful. So I think that's
9:14:02all for this particular video. I think
9:14:03we have covered almost most of the
9:14:05things this is more than enough. Believe
9:14:06me or not if you can understand all
9:14:08these things and do right you will be in
9:14:10a very good position. So if you like
9:14:12this video give a like and I will see in
9:14:14my next video. Till then good luck and
9:14:16peace. All right everyone. So now this
9:14:18is the time that we are going to build
9:14:20our actual project. So this will be a
9:14:22complete practical section and in this
9:14:24project we are going to apply all the
9:14:26concepts that we have learned so far
9:14:28right and I'm pretty much sure that you
9:14:29have already covered the previous uh
9:14:31posgress uh section I already mentioned
9:14:34multiple times that that is actually
9:14:35mandatory and prerequisite and it's
9:14:37going to give you a proper idea that how
9:14:39you can uh write SQL queries right how
9:14:42what are the concept of postgress and
9:14:44all these things so what are the things
9:14:46we're going to understand in this
9:14:47particular project and why this project
9:14:48is very very important even though I'm
9:14:50Pretty much some of you already know
9:14:53CRUD, JWT O, Google Earth, all those
9:14:55things. But still this project or
9:14:57whatever you are going to build will be
9:14:59a complete game changer for all of you.
9:15:02Why? Because what are the things that we
9:15:04are going to learn? First of all, you
9:15:05have to understand that this project is
9:15:07going to give you complete idea on how
9:15:09you can create a proper NodeJS project.
9:15:12How you can work with the Node Express
9:15:15Postgress with Docker. What is or what
9:15:19usually a proper NodeJS project folder
9:15:22structure looks like? What will be the
9:15:24proper and best practices? How you can
9:15:27do proper error handling? Uh form
9:15:30validation. Each and everything we are
9:15:32going to cover why I've taken this
9:15:34particular project little basic to
9:15:35intermediate level because this is going
9:15:37to help you even though you know lot of
9:15:39things in node still I can guarantee
9:15:40this is going to give a complete
9:15:42different idea that how you can create a
9:15:44proper full node project. So first what
9:15:47we will do right so you can see that I
9:15:49have a package dojson now this is I
9:15:50think we have done multiple times so
9:15:52that is the reason I've already created
9:15:53a package dojson with three dev
9:15:55dependencies we have the node types tsx
9:15:57and typescript that's it and in the
9:16:00tsconig I've created a tsconfig dot uh
9:16:03json file now here you'll see that one
9:16:06thing that we are using source folder so
9:16:09source will be where we are going to
9:16:10write all our source code and also we
9:16:13are going to have our main env file
9:16:15where we going to add all our env
9:16:17variables. Okay. But first let's
9:16:19understand that what actually we are
9:16:21going to build in this particular
9:16:22project. Okay. So now consider like the
9:16:25so what we'll do right. So let's say
9:16:27this is our main capstone project or
9:16:30whatever project you are building. You
9:16:31are working in a freelance project or
9:16:33maybe let's say you are working in a
9:16:35company. At the end you have to
9:16:36understand one thing is uh very
9:16:38important that everything whatever
9:16:40you're going to build is nothing but a
9:16:42CRUD. Now this is I usually mention in
9:16:44all my videos. What I mean by this CRUD
9:16:46is nothing but when you're going to
9:16:47create something, when you're going to
9:16:49read something, when you're going to
9:16:50update something and when you're going
9:16:52to delete something. So how this
9:16:54particular uh project looks like? So
9:16:57here we are going to have main two uh
9:16:59roles. Okay, one will be normal user and
9:17:01one will be our super admin or admin.
9:17:04And in this project we are going to have
9:17:06only one admin. Why? When you work with
9:17:08one admin and you'll create a project,
9:17:10right? You will see that no matter how
9:17:12complicated the project is, even though
9:17:15let's say some project you're building,
9:17:17you're going to have a separate role.
9:17:19Let's say you're going to have a user,
9:17:20you're going to have a admin, you're
9:17:21going to have a support role, still it
9:17:24will be much easier for you to do all of
9:17:26these. So you have to make your basics
9:17:27very strong. So that is the reason again
9:17:30in my previous NodeJS uh project also
9:17:32although that was little basic like we
9:17:33have used MongoDB and all and also that
9:17:36project we haven't used uh TypeScript
9:17:38and postgress but still in that video
9:17:40also that I uploaded maybe two years
9:17:42back I also taken the same uh uh role
9:17:45user and admin I'll see that that video
9:17:47also got got pretty good response why
9:17:50because we'll try to make things simpler
9:17:52and then we'll try to implement this one
9:17:54without using any AI tools. Okay. So
9:17:57that is another good practice. If you
9:17:59try to complete this particular project
9:18:00without making use of any AI tools, it
9:18:03will be much better. So you're going to
9:18:04have a normal user and admin. User is
9:18:07going to do what is user is going to
9:18:09create support task. Okay. So I'm just
9:18:11going to take as short as st support
9:18:13task. So user will be able to create
9:18:16support task. User will be able to see
9:18:19all the support task that is created by
9:18:22this user only. Means let's see if I
9:18:24have a user A and user B and user A
9:18:27created two two support task. User B
9:18:29created five support task. User A will
9:18:33be able to see only uh task created by
9:18:36him. User B will be able to see the
9:18:38support task created by user B. But what
9:18:41about the admin? So what admin will be
9:18:43able to see? Admin will be able to see
9:18:45both user A and user B task. So admin
9:18:48will be able to see seven task. So admin
9:18:50has the capacity to view all the task.
9:18:53So that will be one feature. Then so
9:18:55user will be able to create task. User
9:18:57will be able to see task. User will be
9:18:59able to update their task. What I mean
9:19:01by this user A only will be update his
9:19:05task. User B only will be able to update
9:19:07his task. Same for delete also. Okay. So
9:19:11this what will happen when you create
9:19:13this particular part. This is going to
9:19:15give a proper clear understanding of how
9:19:17this creation means card usually works.
9:19:20Okay. But this is not that much simple.
9:19:22Why? Because before this we will have a
9:19:24authentication layer. So something like
9:19:25this. Let's say you have your user, you
9:19:28have your admin and here you are doing
9:19:30some activity. But immediately you are
9:19:31going to have authentications.
9:19:33Authentication means until unless this
9:19:35user is logged in they will not be able
9:19:38to create anything. Right? So how we are
9:19:39going to do the authentication? So here
9:19:41what I decided right this is I'm going
9:19:44to make little complex. So here we are
9:19:45going to have both email and password
9:19:47login. Okay. And at the same time we are
9:19:51also going to have a Google login. Okay.
9:19:53So both together. So if you want user
9:19:55will be able to uh login using or
9:19:58register using email and password at the
9:20:00same time if they want they will be able
9:20:01to login using Google. But if this
9:20:04particular user is already logged in,
9:20:06okay, using that particular email and
9:20:08they try to login with the same Google
9:20:10email. So in that case they will not be
9:20:12able to login. Okay. So this is what we
9:20:15are going to do. So this will be our
9:20:16authentication. So this is going to give
9:20:18you a proper understanding of how JWT
9:20:20works. How we are going to implement
9:20:22middleware, right? Middleware means
9:20:24let's say user A try to see user B task,
9:20:28it will not happen, right? So in that
9:20:29case we have to have some protection. So
9:20:31we're going to have some kind of
9:20:32middleware. So that that medial where is
9:20:34going to check whether that particular
9:20:36user has that permission or not. If that
9:20:38user don't have the permission so it
9:20:40will not give that user to do that
9:20:42particular task. So for example let's
9:20:44say admin admin will be able to see all
9:20:46his task. So in that case we have to see
9:20:49whether that particular user is actually
9:20:51admin user or not. If that user is admin
9:20:54user so in that case only we are going
9:20:55to give that user permission or else we
9:20:57will simply say that okay you are not
9:20:58admin you will not be able to do this
9:21:00particular task. Okay. So these things
9:21:03we are going to build. Third, what
9:21:04you're going to do do right for admin.
9:21:06Admin will be able to do a file upload
9:21:08feature. So we are going to have a file
9:21:10upload feature. Okay. This file upload
9:21:12feature what we going to do? Admin will
9:21:14be able to upload some banners. Okay. So
9:21:16we are going to have some banners
9:21:17feature. We are going to use malter and
9:21:20we are going to use cloudinary both
9:21:22along with our posgress DB. Okay. So
9:21:24admin will be able to upload assets.
9:21:27Okay. that assets we are going to store
9:21:30in our cloudinary as well as that asset
9:21:33URL means the image URL we are going to
9:21:35store in our posgress DB okay so this is
9:21:38what we are going to do and then at the
9:21:40end we are going to have our background
9:21:42job feature but remember before we going
9:21:44to do background job functionality we
9:21:46need to also have a radius uh section so
9:21:48that video also have I have in my
9:21:51channel I'm pretty much sure I think
9:21:52most of you haven't watched that video
9:21:54because that video didn't get proper
9:21:55response what I'm going to do again
9:21:57these This will be mandatory section. So
9:21:59this video also I'm going to add and
9:22:01then we are going to do the background
9:22:03job feature. So this is this will be a
9:22:04big one. Okay. Because there are a lot
9:22:07of things you are going to understand in
9:22:08this particular project. It's going to
9:22:09give you overall idea how you can create
9:22:12a proper NodeJS project. So with this
9:22:14now let's get started. The first thing
9:22:15what we're going to do right. So first
9:22:17we need to install some of the packages.
9:22:19Okay. So first what we are going to
9:22:21install. So first let's do one thing. Uh
9:22:24if I go to package.json JSON right you
9:22:26will see that we have typescript tsx and
9:22:29types/ node correct and now what are we
9:22:33going to do right in the source we are
9:22:35going to have a entry file now as I
9:22:37already mentioned what actually entry
9:22:39file is this entry file or the server.ts
9:22:42TS simp simply will be our first entry
9:22:45file where it will simply check that
9:22:47okay whatever code we have written each
9:22:49and everything should be combined and we
9:22:52are going to add all those logic in the
9:22:53server.ts file. So what I mean by this
9:22:55let's say in this particular project we
9:22:57[snorts] are going to have 10 API
9:22:59endpoints. So now when we are going to
9:23:01build this particular project right so
9:23:04this when this code will run right so
9:23:06code needs to understand right what is
9:23:08our first file that I need to see. So in
9:23:10this server.ts ts file. This would be an
9:23:12entry file. So whenever code we are
9:23:14going to run, it will check this file.
9:23:16Okay, then it will say now all these 10
9:23:18routes we have added here. So then it it
9:23:20can go to that each and every file and
9:23:22it it can see that whatever logic we
9:23:24have written and based on that it's
9:23:26going to do that. So what I simply mean
9:23:28by this that this is a entry file which
9:23:30is mandatory. This is where we are going
9:23:32to run our main code or this is where we
9:23:34are going to run our express server.
9:23:36Okay. But before that let's not go into
9:23:39too much uh uh what is that too much
9:23:43concept but let's see what actually
9:23:44express is do what is express js okay
9:23:48because anyways we are going to
9:23:49understand all of this practically so
9:23:50express is nothing but it's a framework
9:23:53whatever you have learned so far you see
9:23:54that in the beginning section you have
9:23:56understood all the code uh nodejs
9:23:58concept and also the very important http
9:24:00section right so what express is going
9:24:03to give you right so this is a simple in
9:24:05simple way this is going to give you
9:24:06some of the features
9:24:08If you don't use express those things
9:24:10you have to manually write and you have
9:24:12to implement again without express also
9:24:14you'll be able to do this but this is
9:24:16actually going to give you some of your
9:24:18see if you uh notice right it's a
9:24:20lightweight wrapper on top of NodeJS
9:24:22build networking features as simple as
9:24:24that means it is using NodeJS in the
9:24:26background it's using NodeJS features
9:24:28only but this is going to help you or
9:24:30it's going to give you it's going to
9:24:32give you some of the out ofthe-box
9:24:34features that is going to simplify the
9:24:36code that's needed to build web server,
9:24:38web application and restful APIs. As
9:24:40simple as that. So in in definition wise
9:24:44express will be a minimal opensource
9:24:46framework that built on top of NodeJS
9:24:49networking or NodeJS built-in features
9:24:51and that is going to give you some out
9:24:53ofthe-box features that you need to
9:24:56build web servers web application and
9:24:58restful API means it's going to give you
9:25:00some extra advantage that if you don't
9:25:02use it you have to write manually all
9:25:04those things but again if you don't use
9:25:06this one still you will be able to
9:25:08implement those things also. So this is
9:25:10what express is. So first what we are
9:25:12going to do right. So first we'll do npm
9:25:14install express. Okay. So I'm going to
9:25:17install express first. So that will be
9:25:18our first. So I'll do npm install
9:25:20express. So let's install this. If you
9:25:23go to package dojson, you can see that
9:25:25we have added the express. And also
9:25:26let's install the uh types also. So I'll
9:25:29do npm install d. And here I'm simply
9:25:32going to do add the types
9:25:35express.
9:25:38Okay. So types also we need because we
9:25:41are using typescript. So this is the
9:25:42first thing. Second what actually env is
9:25:47I think in the core module we have
9:25:49already discussed about the env
9:25:50variables right. So env is again it's a
9:25:52package right? I think we have already
9:25:54discussed this one. So it's a package
9:25:55that will help us to read our env
9:25:57variables because when we are going to
9:25:59have all these variables that we need
9:26:02for this particular project we can't
9:26:04directly hardcode all those things in
9:26:06our code. So that is the reason we need
9:26:07to keep all of this in a separate env
9:26:09file. Second, when we are going to use
9:26:11some sensitive information, let's say
9:26:12you're using some password or you are
9:26:14using some Google uh credentials secrets
9:26:18so that you just can't expose in your
9:26:20code. Consider this particular project
9:26:21is a public source project means you are
9:26:24going to post this one to your GitHub
9:26:26anyone can see. Now let's say you added
9:26:28your Google secret directly in your
9:26:29code. Anyone can copy and can misuse,
9:26:31right? So that is the reason we need a
9:26:34separate file where we are going to add
9:26:35all of these. So this is where we need
9:26:38file. Okay.
9:26:40So now here we are going to do npm
9:26:42install env.
9:26:46That's it. And then also we need
9:26:49something called course. Okay. So this
9:26:50we are going to discuss later. For now I
9:26:52think this is fine. So first we have
9:26:54installed uh express types node types
9:26:59tsx that is that is going to help us to
9:27:02run our typescript project and then we
9:27:04have typescript env and express these
9:27:08two we have installed as a dependency
9:27:10and these all are dev dependency we have
9:27:12already know the difference between
9:27:13dependencies and the dev dependencies
9:27:15okay so now first of all what we're
9:27:17going to do right so first we need to go
9:27:19to our source so let's create our basic
9:27:22folder structure now these This folder
9:27:23structure whatever we are going to
9:27:24create will be extremely important. Why
9:27:26this is extremely important? Because you
9:27:28need to know that how why we are
9:27:30creating each and every folder and what
9:27:31is the reason or what is the
9:27:33responsibility behind creating each and
9:27:35every folder. So first we are going to
9:27:36create a config folder. So this config
9:27:39is going to hold all our config related
9:27:40information. Then I'm going to create a
9:27:42leave folder. So leave folder is going
9:27:45to handle all our utils related. So
9:27:48let's we are creating some helpers.
9:27:50Okay. Config folder is going to do what?
9:27:52configuration related things. Okay, for
9:27:53example, let's say we are going to
9:27:54manage our env here. Then we are going
9:27:57to have our middleware. Now middleware
9:27:59concept can be little tricky. We are
9:28:01going to understand what actually middle
9:28:02words are. But for now, let's create one
9:28:04middleware folder and then we are going
9:28:07to create a routes folder. This is where
9:28:08we are going to create all our routes.
9:28:11So for now these fold are fine. But
9:28:12before we go forward, right, let's
9:28:14understand what middleware is because
9:28:16you don't have to know coding for this.
9:28:18Let's try to simplify this one. Consider
9:28:20like this that you have your user here.
9:28:23Okay. And then you are doing some task
9:28:27but this task you have to do it only if
9:28:31this user is a logged in user. Loged in
9:28:34user means if until the user is actually
9:28:38logged in. We don't know that actually
9:28:40this user is a user or this user is a
9:28:42scammer. You don't know right? So that
9:28:44means you need something to understand
9:28:46this one. So this is where we have
9:28:48something called there is a barrier
9:28:50right so it's like a middleware so this
9:28:52middleware is going to check that if
9:28:54this user has certain permission or not
9:28:56if this user don't have permission so
9:28:58first of all it's it's going to check it
9:29:00has a permission if it has permission
9:29:02it's going to give you so it's going to
9:29:03give you okay you can go and do this if
9:29:06it don't have permission it's going to
9:29:07block the request here so this is the
9:29:09task of a middleware middleware is like
9:29:11a middle person it's going to do
9:29:13something now it's don't have to uh
9:29:15about always this user and permissions
9:29:17it can be anything right but the
9:29:19important part is that in the node
9:29:21middleware you have to understand that
9:29:22we have something called next concept
9:29:25now you need to know what actually this
9:29:27next is until unless we're going to
9:29:29implement in the code but you need to
9:29:30understand in a very simple way
9:29:32middleware is like a middle person
9:29:34that's going to do some task or it's
9:29:36going to check something and based on
9:29:38that it's going to move on to the next
9:29:40task. So in this case the next task is
9:29:42this one or else it's going to move on
9:29:44to the next route handler. So either it
9:29:46will move on to the next task or it will
9:29:50move to the next route handler and this
9:29:52you'll understand once we'll implement
9:29:54the code. Right? So for now first let's
9:29:56do one thing. Let's go here and then
9:29:59first let's go to env. Okay. And in the
9:30:01env what I'm going to do so first I'm
9:30:03going to take that okay this is my env
9:30:06file where we're going to have all our
9:30:08variables. So first of all we need to
9:30:09understand where we want to run this
9:30:11particular code. So now let's say I
9:30:13wanted to run this on port and I'm just
9:30:15going to give I'll give some random okay
9:30:17because I already have maybe some other
9:30:19port that are already occupied. So I'm
9:30:22just going to give this one as 5010. Now
9:30:24this is the port I wanted to run this
9:30:26particular project. As simple as that.
9:30:28You can use any port you want. For
9:30:30example, you can use 3,000, you can use
9:30:3230,0001, you can use 4,000. Okay? Or
9:30:34maybe let's use 4,000 here. So I'm going
9:30:36to use port 4,000 for this. Okay? And
9:30:40then I'm just going to use here node
9:30:42env. And in this case we are using
9:30:44development because we are doing
9:30:46development now. So we going to have two
9:30:47env now. Okay. So now what we going to
9:30:50do right we will go to our config and
9:30:53this is where we are going to create our
9:30:54base structure first. So we'll create
9:30:56env.ts and here what we going to do
9:30:59right? So first of all we need to load
9:31:01all our env variables right because
9:31:03until unless we're going to load the env
9:31:04variables we'll not be able to read it.
9:31:06So this is where we need the env
9:31:08package. So I'm just going to do env
9:31:10from
9:31:12env. And then how we are going to load
9:31:14it. Okay, I'll minimize this one. So to
9:31:16load this one, you're going to use
9:31:17something called env.config. Now this
9:31:20config is going to do what? It's going
9:31:21to load your env file containing into
9:31:23process. You have discussed remember
9:31:25process.default uh process. Default
9:31:28process. Env by default. Okay. If key is
9:31:32present, it simply attempts to load
9:31:33encrypted. Okay. Fine. First first you
9:31:35understand this one. loadb file contents
9:31:38whatever you have inside this it's going
9:31:40to load into process by default okay now
9:31:44this is very important because you are
9:31:46going to use this one a lot and then I'm
9:31:48just going to use export con and I'll do
9:31:51env
9:31:52here I'm just going to add all these
9:31:54whatever I have so first I have a port
9:31:56correct so the port will be so I'm going
9:31:58to take a number and here I'm just going
9:32:00to take process env dot
9:32:04so port here so I'll do
9:32:07and always give this uh value here.
9:32:10Okay, default. That's it. Then I'm
9:32:12simply going to check uh that if this is
9:32:15the products and environment or not. So
9:32:17I'll do is production send here. I'm
9:32:19just going to do process.v
9:32:21dot. So we have the node env.
9:32:26I'm just going to keep this one as
9:32:28development by default. So when this
9:32:30will be is production when this node
9:32:31enval to production that time it will be
9:32:35production if this is not that means we
9:32:37are doing a development okay so that's
9:32:40it I think these two and also let's do
9:32:41node envo
9:32:43so here also I'm just going to do
9:32:45process env
9:32:48or else this will be development and
9:32:50then I'm just going to keep this one as
9:32:51as const that's it so this will be my
9:32:54env file you will understand one concept
9:32:58remember I already mentioned the idea of
9:33:00this project is to give you the proper
9:33:02understanding of how you can create
9:33:03NodeJS project. Right? Now let's say you
9:33:04added two more ENV. You'll come here and
9:33:08you'll add two more ENV in this file.
9:33:10Now what will happen like when you're
9:33:11going to do env dot you're going to get
9:33:13this env. Environ
9:33:17is production and you can directly use
9:33:18this one like this. Okay. So this is the
9:33:20idea of this particular file. So this is
9:33:23first one. Now what we going to do
9:33:25right? So first when we need express so
9:33:27express is going to help us to create
9:33:29our web server. So that means we need to
9:33:31run our server correct. So that means
9:33:33first what we going to do right? So
9:33:34let's go to uh this app.ts file. I'm
9:33:38going to create entry file. So this will
9:33:40be my entry file for express. So means
9:33:44all express related logic I'm going to
9:33:46add here
9:33:48and this express related or this app.ts
9:33:51I'm going to add in this server.ts. So
9:33:53this is our main root file. Okay. And
9:33:56this will be entry file for express. So
9:33:58first of all what we need to do here. So
9:34:00first I'm going to do export function
9:34:04and I just do create app or create
9:34:07application whatever you're going to do
9:34:10and then first of all I need to do I
9:34:12need to create my express application
9:34:14right because how we are going to use
9:34:16express features until unless you're
9:34:18going to create the express instance.
9:34:20Correct? So in this case we need to
9:34:21first import express from express and
9:34:26then we are going to simply do express
9:34:28that's it. So what this is going to do
9:34:30create an express application the
9:34:32express function is a top level function
9:34:34exported by the express module. So this
9:34:36is the root and now if you do app dot
9:34:39and this is where you're going to get
9:34:41all of these each and every feature
9:34:43you're getting. So this is where this
9:34:46app is now holding each and every
9:34:48feature provided by express. So now we
9:34:50are keeping this one in a variable and
9:34:52now what we going to do right we are
9:34:54simply going to do app dot use and I'm
9:34:56simply going to do express dot JSON okay
9:35:00this is actually middleware again
9:35:03middleware we are going to understand
9:35:04once we create little uh more logic or
9:35:08once we'll go a little further because
9:35:09you need to understand that how this
9:35:11middleware work and it will be much
9:35:13easier to explain this one practically
9:35:14for now you understand this is actually
9:35:16a middleware that parses JSON And it's
9:35:20only look at the request where the
9:35:21content type header matches the type
9:35:23option. You'll understand what we are
9:35:24doing in this particular case. I'm going
9:35:26to explain and then I'm going to simply
9:35:29do now let's say here what I can do
9:35:32right in this particular file. Now what
9:35:34I mention that when you are going to
9:35:36have a root file when this code will
9:35:38compile this particular file will be
9:35:40read at first. So it's going to check
9:35:42each and everything. Now let's say you
9:35:44are using this create app method here.
9:35:47So then it will go to this particular
9:35:49file and this is where you have to add
9:35:51all your routes, all your middleware and
9:35:53everything. What I need to do right
9:35:55first of all I need to have some feature
9:35:58in this particular uh project so that
9:36:00whenever there is a any error happens or
9:36:03let's say something crashes
9:36:05this particular application should
9:36:06automatically pick that error and it
9:36:08will notify the user. Okay, there is a
9:36:10problem you try after something. So that
9:36:12means we need to have a global error
9:36:14handler. You're getting global error
9:36:17handler. we need to have. Okay. What
9:36:19this error handler is going to do? This
9:36:21error handler is simply going to give
9:36:23you one information. Okay. Something
9:36:24happened. There is internal server
9:36:26error. There is a network error.
9:36:28Whatever. Not network but internal
9:36:29server error happened. So that
9:36:31middleware we need to create. Every time
9:36:33that uh something breaks so that
9:36:35middleware will get executed and then
9:36:37that user will be notified. Okay. But
9:36:40for this before that also we are going
9:36:42to use one more package that is called
9:36:45Pino. Okay. So let's see what actually
9:36:46Pino is. So what is Pino?
9:36:50So it's a logger. Okay, you can see that
9:36:52it's a highly popular opensource logging
9:36:55utility means here whenever we want to
9:36:58notify the user. Okay, let's or maybe
9:37:00let's consider from a developer point of
9:37:02view. When you're developing, let's say
9:37:04you're running the code, you want to
9:37:05check your logger. This is going to
9:37:07generate the logs in a structured JSON
9:37:09format. Okay. Now this is also very
9:37:12fast. You see that this is also very
9:37:13fast. So we going to use this pino
9:37:16package. Okay. So here we will use this
9:37:18pen and then I'm just going to show you
9:37:20I think it's called pino pretty. Okay.
9:37:23So let's see this one pen pretty these
9:37:25two.
9:37:27Okay. So we can directly so this is
9:37:29actually uh how we are going to do this.
9:37:32So you can see that we have a logger. We
9:37:34have to set a label and then you can use
9:37:36some transport here. Okay. So colorize
9:37:38means it's going to enable your color
9:37:40tags. Uh this is the trans. So human
9:37:43readable time stamp. So it's going to
9:37:44create human readable time stamp and
9:37:46also it's going to ignore if you want to
9:37:49ignore something. But for now these two
9:37:50I think more than enough. And also I
9:37:53think we also need to take the target
9:37:55also. I think target is also I think
9:37:57optional. So what we will do right label
9:37:59we need to take and transport we are
9:38:02going to check if this is production we
9:38:04are going to do this. uh
9:38:07no sorry if this is not production we
9:38:09are going to do this or else we're going
9:38:10to do undefined in production fall back
9:38:12to raw altra first JSON string okay so
9:38:15this is what we are going to build uh
9:38:17now remember one thing I wanted to
9:38:19mention see whenever I'll create these
9:38:20videos right so you can see that I'm
9:38:22doing this on real time means I'm
9:38:23actually I don't have all of this
9:38:25created so I'm just checking and writing
9:38:27what I mean by this whenever I'm going
9:38:29to do let's say there is some mistake or
9:38:30some slowness in the explanation it's
9:38:34your responsibility You have to do your
9:38:36own research and you have to learn.
9:38:37You're getting what I'm talking about.
9:38:38For example, let's say there are
9:38:39something I'm not explaining. You have
9:38:42to go or in this case you can make use
9:38:43of some AI tools also that will be much
9:38:46easier. So in this case what you're
9:38:47going to do right. So first let's do npm
9:38:49install. So we'll go here and we'll do
9:38:52npm install pino and then we have pino
9:38:55pretty.
9:38:59That's it. Now where we going to add
9:39:02this pino file? This you are going to
9:39:04add in your leave file. Okay. So this
9:39:07will be a logger.ts. So first what I'm
9:39:09going to do I'll do import
9:39:12pino from
9:39:15pino and then also I'm just going to I
9:39:18think let's do export
9:39:20con logger and here I'm simply going to
9:39:23take pino.
9:39:25So first I'm going to take the label. So
9:39:27label will be where uh okay also one
9:39:30very important point let's do one thing.
9:39:32Let's go to env see what we are doing
9:39:34each and everything you have to
9:39:35understand. So instead of adding
9:39:36directly hard coding there I'm just
9:39:38going to do log level here and I'm just
9:39:40going to keep by default info. Okay. So
9:39:42log level will be info. So now if I'm
9:39:44adding a new one so I need to go to env.
9:39:46And then I'm just going to add a log
9:39:48level and this will be process env dot.
9:39:53So log level or else this will be info.
9:39:58Okay. So now we'll go here and then I'm
9:40:01just going to use env that I need to
9:40:03import and I can use this log label here
9:40:06you're getting. So this is how you're
9:40:07going to do this. So once this is done
9:40:09now we are going to also add a
9:40:11transport. So here I'm going to add a
9:40:12transport. So I'm going to check if this
9:40:14EMV do is production. So in that case
9:40:17I'm going to keep undefined. And for
9:40:19Dave I'm just going to keep a target.
9:40:22And here we are simply going to take
9:40:24let's take this one target as we know
9:40:27pretty
9:40:30also we're going to take options. And
9:40:32here I'm just going to take colorize.
9:40:35Let me just copy from here.
9:40:39Colorize will be true.
9:40:43And also we need this one. Translate
9:40:45time we're going to keep so that we'll
9:40:47get human readable time stamp.
9:40:52I think this is done. Why getting error?
9:40:54Oh, we have to do this. Okay. So I think
9:40:57this is done. So we taking a label which
9:40:59will be log label. By default it will be
9:41:00info because that is what we have added
9:41:02here. Transport target we targeting pen
9:41:06pretty options color is true and
9:41:08translate time sard.
9:41:10Okay. So this is what I need. So now
9:41:12what we can do right we can use this. So
9:41:15maybe let's do one thing. We need to use
9:41:17this one in all the places. First let's
9:41:20go to middleware and then I'm going to
9:41:21create a global error handler. Okay. So
9:41:23I'm just going to do error handler
9:41:27TS file. And now this I already
9:41:30mentioned this is going to give you a
9:41:31general idea whenever there is something
9:41:33goes wrong we are going to trigger this
9:41:35middleware. And this we're going to use
9:41:36in our app.ts file. So here I'm simply
9:41:39going to do export function and I'll do
9:41:41error handler. So first of all here I'm
9:41:44going to take a error. This will be
9:41:46error. Then I'm going to take a request
9:41:50and this will be okay. This particular
9:41:53request is the request object from
9:41:55express. Okay. So this will be now you
9:41:59consider this one as you remember in the
9:42:00HTTP model we have discussed about the
9:42:02request and response. You consider this
9:42:05one similar to this. Okay. I think now
9:42:07this will be easier to understand and
9:42:09this is the reason in the uh HTTP model
9:42:11we have explained all of this in details
9:42:13that if you don't use any third party
9:42:15framework how this will look. So this is
9:42:17consider this one as that only. So this
9:42:19request object this is a response
9:42:21object. So here I'm going to take this
9:42:23one as request then I'm going to take a
9:42:25response because I need to return the
9:42:26response. And now you have this next
9:42:30function here. Okay. Now this next
9:42:32function is extremely important concept.
9:42:34This we are going to understand little
9:42:36later. So for now let's take this one as
9:42:38next function from your express. Okay.
9:42:40Okay. Let me explain what this next
9:42:41function is. So what happen right when
9:42:43you are doing let's say you have a
9:42:44middleware. Okay. And you are doing one
9:42:47user is doing a task and this task is
9:42:49here. So this is task one. Now you have
9:42:54or maybe let's uh let's take this on
9:42:56task one. Let's take this on task two.
9:42:59So this is task two. This is task one.
9:43:02And then in middle you have a
9:43:04middleware. What this middleware is
9:43:06going to do? Let's say user already
9:43:08completed the task one. So this task is
9:43:10completed. Before it will go to T2 which
9:43:14is task two. You have a middleware in
9:43:16middle. So this middleware is going to
9:43:18check something. I already mentioned it.
9:43:20It's going to do something. If this
9:43:22condition satisfies means this condition
9:43:24whatever you given if this satisfies
9:43:26it's going to move to next one. Right?
9:43:28But how it's going to move? This is
9:43:30where this next is actually important.
9:43:32So when you're going to use middleware
9:43:34we are going to call this next function.
9:43:37So next means now we are simply telling
9:43:38middleware oh your task is completed now
9:43:40you have to go to next task. So that is
9:43:43the reason once will move to sorry once
9:43:45you call the next it will go to task
9:43:47two. What will happen if you don't use
9:43:49this next function. Consider user
9:43:51completed task one. Task one now called
9:43:54middleware. Middleware already check
9:43:57condition satisfies. Now it should go to
9:43:59task two. But you haven't called the
9:44:00next function. What will happen? it will
9:44:02be stuck here forever. It will never go
9:44:04to the next part. You're getting so this
9:44:06is where this next function is very
9:44:07important. So whenever you're going to
9:44:09do some functionality or using
9:44:11middleware you need to call the next
9:44:13function only if that needed only if
9:44:15that functionality is needed. Okay. So
9:44:18now this is our next function. What we
9:44:20going to do right? Okay let's take this
9:44:22one. We are going to return void. We're
9:44:24not doing anything here. And then I'm
9:44:25simply going to take my logger from the
9:44:27logger that I have created. And here
9:44:29this logger is going to give you some
9:44:31label. For example, you can use logger
9:44:32dot error logger. fatal logger.info. Now
9:44:36because we creating error handler. So
9:44:38what will happen? We need to do logger
9:44:39dot error. Correct? And this is where
9:44:41you're going to pass the error. This
9:44:43error. Okay. Whatever error will happen.
9:44:45And then I'm just going to give a
9:44:47general message that unhandled error.
9:44:52Okay. Now what we have to do right, we
9:44:54need to return a response back to user.
9:44:57Correct. See whenever you are going to
9:44:58create an application you're going to
9:45:00have your back end you're going to have
9:45:01your UI correct. So when your back end
9:45:04will do ter some task it's going to
9:45:06return the response back. This is where
9:45:08this response object is helpful. So now
9:45:11this is where what we can do right you
9:45:12can do race dot status. Now all these
9:45:14things now you're seeing this is
9:45:16actually provided some of the things
9:45:18provided by express out of the box. So
9:45:20this is why we need some framework to
9:45:22make make our life much easier. You can
9:45:24do the exact same thing using node HTTP
9:45:27package also. I think we have already
9:45:28discussed this on previously. So here
9:45:30I'm going to return a 500. And now I'm
9:45:32going to return a JSON response back.
9:45:34Okay, this JSON response is going to
9:45:36return a success. This will be false
9:45:39because something goes wrong. And then
9:45:40I'm also going to return a message and
9:45:42this will tell that okay there is a
9:45:44internal
9:45:46server error. Okay. So this will be our
9:45:49global error handler. But how we are
9:45:51going to use this? So to use this one we
9:45:53have to tell express that okay you are
9:45:55going to use this error handler. So to
9:45:57do this one we are going to do
9:46:01uh app dot and you have something called
9:46:03use which is very important right. So
9:46:05this use is going to use something. So
9:46:08what you're simply telling that okay
9:46:09whenever something goes wrong you're
9:46:10going to use this error handler. So it
9:46:12will automatically check that and it's
9:46:14going to give you the error. It's going
9:46:15to throw error. So this is the first
9:46:17thing. Now next we need to create one
9:46:20more middleware. what actually that med
9:46:22and that is not found. Consider you are
9:46:25creating some APIs right user is hitting
9:46:27this login endpoint correct now let's
9:46:30say user it's possible right user can
9:46:32give some random value for example let's
9:46:34see if I go here and I give some random
9:46:36value here whatever you can do here it
9:46:39will not work okay here they have added
9:46:41the logic that whatever you'll put it
9:46:43will always go to here but normally in
9:46:44your application let's say this route is
9:46:46not even present so what we have to do
9:46:48right you have to tell user okay this is
9:46:50not found this route that you are trying
9:46:53to access is not found you're getting.
9:46:55So this is a generic message that you
9:46:58should always implement before even
9:46:59starting your logic. So that is the
9:47:01reason we need one more middleware and
9:47:03this will be not found. DS and this is
9:47:07very simple. Okay. So do export function
9:47:09and I'll do not found and this is where
9:47:12we also need the request and response.
9:47:17So we're going to get request and
9:47:18response. So I'll do not found. So I'll
9:47:21have the request and this will be my
9:47:24request. I'm going to have the response.
9:47:26This will be my response. It's going to
9:47:28return v. And what I'll do right, I'll
9:47:30simply do raise dot status
9:47:33404
9:47:35dot json. And here also I'm simply going
9:47:37to do success will be false and message
9:47:41will be route not found.
9:47:49So save this and now we'll go here
9:47:50again. We'll do app dot use not found.
9:47:54That's it. So it's going to use these
9:47:56two middleware. Okay. Now this is see
9:47:58whatever we are doing at extremely
9:48:00important. These are the base concept
9:48:01that you need to do. Now let's do one
9:48:03thing. Let's go here and understand what
9:48:06actually this is. So I'll do express URL
9:48:08encoded.
9:48:12Okay. So you can see that express
9:48:15encoded is a built-in middleware. Again
9:48:16this is also another middleware that
9:48:18parses incoming request with URL encoded
9:48:21payloads. Okay. Now how we are going to
9:48:23understand this one? This we will
9:48:25understand once you'll implement our
9:48:26CRUD. Remember I already mentioned the
9:48:28concept of CRUD create react because
9:48:30that time when you're going to pass some
9:48:32form data from your UI side. So in that
9:48:34case this the browser encoded the data
9:48:36into long query string format the middle
9:48:39inter blah blah and then it's accessible
9:48:41in your request. body. For now this will
9:48:43be a little tricky to understand but we
9:48:45need to use this one in our main entry
9:48:47file. So for now what we are going to do
9:48:49right we are simply going to use this.
9:48:50So do app dot use express url encoded
9:48:53and then we're going to pass extended
9:48:54will be true. So this is going to
9:48:56middleware that is going to pass your
9:48:58incoming HTML form submission. So
9:49:00whenever you're going to have some kind
9:49:01of form you're going to pass some form
9:49:03data. This is where you need this
9:49:05particular middleware. Okay. So now
9:49:07we'll go here and after this I'm simply
9:49:10going to do app dot use and I'll do
9:49:11express dot url encoded and you're going
9:49:14to pass a extended will be true.
9:49:18I hope this is clear. So with this this
9:49:20part is completed. So in the next
9:49:21section what you're going to understand
9:49:22we understand what actually course is
9:49:24and then we'll create our first route.
9:49:26We are going to create our entry file.
9:49:28This is not yet created. We are going to
9:49:30run our express server and we'll test in
9:49:32postman that if this is working or not.
9:49:34So let's do this this one in the next
9:49:36part. All right. So what actually course
9:49:38is right? So course is nothing but cross
9:49:40origin resource sharing. Now you
9:49:41understand this one with practical way.
9:49:43So consider you have a front end URL you
9:49:45have a back end URL. Correct. Now what
9:49:47usually happen right? So first of all
9:49:49let's understand how you can do this. So
9:49:51we're going to install this course
9:49:52package and then you simply tell our
9:49:54express. So app dot use means what app
9:49:57is your express app. So you're going to
9:49:58tell express okay you are going to use
9:50:00quartz. That means you're going to allow
9:50:02all cross origin request. But what will
9:50:05happen? Let's say you have a certain
9:50:06front end URL and here in this case you
9:50:09can see this is actually very dangerous
9:50:10right so you should restrict access to
9:50:13your specific front- end domain only so
9:50:15that means you have a front end domain
9:50:17and you want that particular domain only
9:50:20can call your backend URL or that
9:50:23particular domain only can call your
9:50:25backend endpoint or backend API so in
9:50:27that case what you have to do right you
9:50:29have to explicitly say okay whenever
9:50:32you're going to set this course in your
9:50:33back end code something like this that
9:50:35in know in my course option I have a
9:50:37origin this is my front end URL this is
9:50:40the method that I want or this is the
9:50:42allowed HTTP action and then you can use
9:50:45some other options also here okay maybe
9:50:47let's see if you're using cookies you
9:50:49can from your u you can you have to pass
9:50:51credentials equal to true all these
9:50:53things but first you have to understand
9:50:54that this is how you can uh use a
9:50:56filtered course options mean now this
9:50:59particular origin only can do a request
9:51:02to your backend APIs but in our case
9:51:04what we're going to do right so for now
9:51:06let's do one thing I think we haven't
9:51:07installed the course package I think
9:51:09let's do this
9:51:12so do npm install course
9:51:16clear and then npm install - d
9:51:21we also need the course types
9:51:24that's it and then first of all what
9:51:26we're going to do right so let's go to
9:51:28our appts
9:51:30and I'm going to import here so I'll do
9:51:32import course from course
9:51:38and then uh we'll directly use it here.
9:51:41So for now I'll just do app dot use and
9:51:43then I'll do course if I get time so I'm
9:51:45just going to give you some uh advanced
9:51:47level of exp or maybe let's do this one.
9:51:49Let's keep this one for your node just
9:51:51part two because anyways we're going to
9:51:52create our microservices and all but
9:51:55here you can directly use all of this
9:51:56right. So you can pass a option and then
9:51:58let's say you can give uh this let's say
9:52:00we're going to pass origin you can add
9:52:02all of these all these allowed headers
9:52:04so many options are there. So for now I
9:52:06think this is fine. So this is going to
9:52:07handle your chords. Now what we're going
9:52:10to do right so let's go to routes and
9:52:12then I'm just going to do health dot
9:52:15routes.ts.
9:52:17Okay so this will be our first route
9:52:19that we wanted to create. So first of
9:52:21all you have to understand now how you
9:52:22can create a express route. So here we
9:52:26have something called router. So that we
9:52:28are going to import. So we are going to
9:52:29import this one from express and this
9:52:31will be my router. So now whenever I'm
9:52:33going to create a router I need to use
9:52:36this router just like in my app.ts when
9:52:38I'm creating express application I need
9:52:40to use this correct. So that's why first
9:52:42of all I'm just going to do export con
9:52:44and I'll do health route
9:52:47or router and then again I need to use
9:52:49this. So that means now this health
9:52:52router is going to give me all the
9:52:54information that I need for example all
9:52:56this method each and every property you
9:52:58can use. So what you're doing right
9:52:59you're putting all you're taking all the
9:53:02functionality or feature that this
9:53:04particular thing will give and you're
9:53:06assigning this one to a variable. Now
9:53:08what I can do right I can do a health
9:53:10router and let's say I wanted to create
9:53:11a get request. Okay so I can do like
9:53:14this get if I wanted to create a post
9:53:16request I can do post. If I wanted to
9:53:18create a put, I can do put. If I wanted
9:53:20to delete, you have options. So many
9:53:22things. So here I'm just going to do a
9:53:24get. This first of all you have to give
9:53:26the path. So this will be your API path.
9:53:28Okay, this will be your API path. Now
9:53:31this is important concept. So whenever
9:53:33let's say you have a front end URL that
9:53:35is running on local host 3000 correct
9:53:40now from your front end when you're
9:53:42going to call this AP endpoint, how
9:53:44you're going to call where your back end
9:53:46is running? your back end is running on
9:53:47localhost 4,000. So now this will become
9:53:51local host 4,000 / health. Now let's say
9:53:55what I wanted to do right I don't want
9:53:57to do like this for [snorts] all my API
9:54:00endpoints I wanted to add a prefix API.
9:54:03So in that case what you can do so you
9:54:04have to do / API/ health/ API/ users/
9:54:09API/ product something like this. Okay.
9:54:12So now here what I'll do right. So for
9:54:14now I'm going to take a health and now
9:54:17here what I have to do right you have to
9:54:18create the handler. Okay. So here I'm
9:54:20going to have my request object.
9:54:23I'm going to have my response object.
9:54:26And then what I need to do I need to
9:54:28return a response back. Response back to
9:54:31the user. You think always like this.
9:54:33You have to return back something to the
9:54:35user because at the end your user is
9:54:37going to see something on UI. Correct.
9:54:39So you're going to do raise dot status.
9:54:41This will be what? 200 because this is a
9:54:43success and this will be JSON and here
9:54:46you're going to pass a success would be
9:54:48true and then I'm going to pass a
9:54:50message. I'll do health route is
9:54:54working. So this will be the first route
9:54:57that I have created. Okay. Now what is
9:54:59what will be best approach here? You
9:55:01should you can directly use this in
9:55:02app.ts but I'll not suggest what you
9:55:05should do right you should always create
9:55:06a entry file here. So this will be your
9:55:09root route file. Okay. So this is where
9:55:12you're going to combine all your routes
9:55:16of application means every route. Let's
9:55:18say you're having a 1,000 route also
9:55:21you're going to add it here. Okay. So
9:55:23now again we need to create our router.
9:55:26So I'll do uh import something from
9:55:28express. So I'm just going to take
9:55:30router.
9:55:32And now what I'm going to do right I'm
9:55:34just going to do export con. I'll do API
9:55:37router and this will be router. So now
9:55:41what I need to do right I need to tell
9:55:42that okay this API router now needs to
9:55:45use this health router. Okay how we are
9:55:47going to do this? So it's simply going
9:55:49to do okay API router you have to use
9:55:52this health router that's it so now what
9:55:55you have done you have actually plugged
9:55:57this health router in this component. So
9:56:00you're plugging
9:56:02all routes
9:56:04in one place. Okay. So later let's say I
9:56:08created a user router. So you can do app
9:56:10API router dot use and you'll do user
9:56:13router. So you can have user router. I'm
9:56:16just showing okay these things are very
9:56:18important. Let's say you're creating a
9:56:19post router. You're creating a admin
9:56:22router. You're creating let's say
9:56:24dashboard router whatever. So you're
9:56:25going to combine all of these here in
9:56:27this component. Something like this.
9:56:29So I think this is done. Save this. So
9:56:31now what we have to do right? We have to
9:56:33use this in this app dot ts. Now this is
9:56:35one of the most important concept that
9:56:36we are going to understand. So now what
9:56:38I have to do right see this is why we we
9:56:41created this. So we don't have to use
9:56:42all this individual route in this
9:56:44component. What I can do right you can
9:56:46simply tell okay app dot use and this
9:56:48will be our base API endpoint. Now this
9:56:51is very very important. App dot use this
9:56:55starts with API. So that means when we
9:56:58are going to call this one from our
9:56:59front end it will understand okay this
9:57:01is the API that we are calling and here
9:57:03we are going to simply pass API router
9:57:06that's it. So now if you go here what
9:57:10will be the final
9:57:12uh endpoint here final endpoint will be
9:57:15your backend URL which is localhost
9:57:194000
9:57:20/ API because you are actually adding a
9:57:24prefix here. Okay, this is your prefix
9:57:26API. Okay, and then you're going to have
9:57:29/ health like this. So this will be your
9:57:32actual route. So health first API will
9:57:36come and then health will come here like
9:57:38this. So I think this is completed and I
9:57:41think this is done. Now what you're
9:57:43going to do and at the end you're going
9:57:44to return the app here.
9:57:47This app that's it. So now this is
9:57:49completed and then we'll go to our
9:57:51server.ts. This will be our entry file.
9:57:53This is where we are going to do what?
9:57:55We are going to call this create app.
9:57:58Call this create app means we're going
9:57:59to call this method and we're going to
9:58:01run our server because we haven't run
9:58:03the server yet. Okay. So I'm just going
9:58:05to do con app will be create app. This
9:58:10is the first thing. And then I'm simply
9:58:12going to do app.list.
9:58:14So it will listen to a port, right?
9:58:16Which port? We have the port 4,000. So
9:58:18we are going to do envo
9:58:22and then we're going to take a call back
9:58:24and here I'm simply going to do logger.
9:58:26We already have the logger right and
9:58:28we'll do logger.info. And now I'll do
9:58:30server is now running on port. And here
9:58:36let's do like this on port http
9:58:41localhost.
9:58:43And then here I'm just going to pass the
9:58:44env.
9:58:47That's it. Now you'll see that how much
9:58:49cleaner this particular file is and that
9:58:51is the reason we mentioned that this is
9:58:52our entry file. So what will happen when
9:58:54the code will run it will come here it
9:58:56will check this it will go here it will
9:58:59check all of this it will check okay
9:59:00this route we have it will go here it
9:59:03will check again we have the health
9:59:04route it will go to this particular file
9:59:08you're getting so simply we are plugging
9:59:10each and everything and we are keeping
9:59:12in a single file so now we have to go to
9:59:15package dojson and then I'm just going
9:59:17to add some script here okay let's
9:59:19remove this
9:59:21uh what are the script we need so Let's
9:59:23take a div script. So here I'm just
9:59:26going to take a tsx watch. I think this
9:59:28you already know we have the
9:59:30source/server.ts
9:59:31file. So this is our entry file. Okay.
9:59:34Then I'm just going to do a build. Build
9:59:36will be our ts uh tsc. And then also I'm
9:59:41just going to take a start and start
9:59:44will be all node dish folder because if
9:59:47you go to ts config we have the dish
9:59:50folder that where we are going to
9:59:51compile and we are going to keep the
9:59:52code. So here we will we'll be having
9:59:54dish/server.js
9:59:56file.
9:59:58Save this. And now let's go here. And to
10:00:01run this what we have to do we have to
10:00:02run the script. Correct? And also here
10:00:05we can do like this. So we will do dist
10:00:08/ server.js. JS save this and I'm just
10:00:12going to do npm run dev
10:00:16that's it server is now running on and
10:00:18this is the reason we have using
10:00:19coloring so you can see that it's coming
10:00:21as a color so local host 4,000 correct
10:00:23now we'll go here copy this
10:00:26and then I'll just paste it here and
10:00:28I'll do / health let's see what is
10:00:30happening and I will send here route not
10:00:33found fantastic now from where it is
10:00:35coming I'll see that each and every
10:00:37middleware that we have created that are
10:00:39getting executed. So now this health
10:00:41route is not present correct because
10:00:43what you have to do you have to do /
10:00:44API/ health. So that is the reason
10:00:46you're getting route not found but this
10:00:48is actually coming from here not found.
10:00:50So this middleware is getting executed.
10:00:53You're getting so now this will
10:00:55automatically check that okay this route
10:00:57is not found. I need to run this one.
10:00:59But if I just do localhost 4000/ API/
10:01:02health send this you're getting health
10:01:04route is working. Fantastic. So in this
10:01:06case now it will go check here. it will
10:01:08go and okay there is a health route is
10:01:11present so that means this is working so
10:01:13this will be the base setup that we have
10:01:16done so we've understood about the
10:01:17course and how we can create express
10:01:19route and then express server so with
10:01:21this now let's move on to the next one
10:01:23okay so what will be our next step now
10:01:25remember for this particular project we
10:01:27are going to use docker and uh database
10:01:30will be definitely possess right now
10:01:32what I wanted to mention right uh if you
10:01:34are not aware because see for me it's
10:01:36not possible to again cover docker and
10:01:38docker compose all of these what I'll
10:01:40suggest you just go to YouTube and just
10:01:41search with my name and uh just type
10:01:44DevOps and you'll see that you are going
10:01:45to get multiple DevOps videos and I also
10:01:49have multiple Docker videos also so if
10:01:51you want you can watch this video also
10:01:53DevOps full course part two so here I
10:01:55have covered the uh docker in details
10:01:58same you can also if you want to learn
10:02:00with GitLab CI/CD you can watch this one
10:02:03or the best will be you can watch the
10:02:04first one okay so if you click here and
10:02:07you'll see There there will be time
10:02:08stamp and where you will be able to see
10:02:10docker and docker compose only this part
10:02:12you can watch from this uh time stamp
10:02:14okay why I'm saying this one because see
10:02:17when uh we are going to use or whenever
10:02:20we are going to create any products
10:02:21level nodejs application right
10:02:23especially in the part two we are going
10:02:24to cover microservices in part three we
10:02:26are going to have some more advanced
10:02:28topic docker is one of the best
10:02:30absolutely best uh thing that you can
10:02:32use okay there is no competition because
10:02:35whenever you go to any product based
10:02:37company, service bus company doesn't
10:02:38matter you'll see that almost all the
10:02:41company more than I will say 80 to 90%
10:02:43of the projects they are using docker
10:02:46okay uh and also it's industry standard
10:02:48and that is the main reason I've decided
10:02:50to use docker for this particular
10:02:52project also and this is very very
10:02:54simple what we're going to do right we
10:02:55are not going to have multiple services
10:02:57for now we are going to have only one
10:02:59service and if needed later we are going
10:03:00to add more so we are going to have only
10:03:02one service and that will be posgress
10:03:04and you can see that maybe let's Uh
10:03:06first of all let's copy this and then
10:03:08I'm just going to change couple of
10:03:09things. So what we going to do right in
10:03:11this project root we are going to create
10:03:14our docker compos file. Okay. So in the
10:03:16project root you create docker compose
10:03:19do yimml. The reason is very simple
10:03:21because in this particular section we
10:03:23are going to create all our uh sql
10:03:25schemas migration and also we are going
10:03:28to create our own custom migration
10:03:30script. We are not going to use any
10:03:31third party packages. Okay. So here just
10:03:33paste it and then I'm just going to
10:03:35change this one from support desk
10:03:37posgress to let's do this one as nodejs
10:03:40capstone
10:03:42project. Okay that's it and I think we
10:03:46don't have to make any other changes. So
10:03:48what we are doing we are using port. So
10:03:50if you want you can use a different
10:03:51port. Maybe let's say I'll use 5 440.
10:03:55Uh and then uh we are using posgress
10:03:57image. This is our container name. This
10:03:59will be our posgress user posgress
10:04:01password and also posgress db. You can
10:04:03also change this one to something else.
10:04:05Maybe let's do this one as nodejs
10:04:07capstone.
10:04:10Okay. So this is the first thing that we
10:04:12are going to use. Okay. Once we'll do
10:04:14that what we are going to do right also
10:04:17I'm pretty much sure that you should
10:04:18have docker desktop installed on your
10:04:22device. You can see that I already have
10:04:24this one. So what we have to do? We have
10:04:25to start this particular service and
10:04:27also we need to go to our renv and we
10:04:30need to add our DB URL also. But before
10:04:32this first let's do one thing. Let's
10:04:34start our uh docker service. So what I'm
10:04:36going to do I'm just going to do docker
10:04:38compose up - d and let's see what you're
10:04:41getting.
10:04:45All right. So you can see that this is
10:04:46now created and you're going to have
10:04:48this capstone project. And if I go here
10:04:50you can see that this is running on this
10:04:51particular port. So that's it. We don't
10:04:54have to make any other changes for now
10:04:55because we are going to understand each
10:04:57and everything manual way. What I mean
10:04:59by manual ways if I want I can I thought
10:05:01that I'm going to use some custom sorry
10:05:03some packages for migration and
10:05:05everything. But I think some of you also
10:05:06commented that no we want to learn uh
10:05:09our own manual migration. So that is the
10:05:11reason we are going to create our own
10:05:12SQL migration logic. Okay before this
10:05:15what we going to do right we are going
10:05:17to add one database URL here. So I'm
10:05:19just going to do database URL and let's
10:05:21give this one as. So you'll have to do
10:05:22postgress because we'll do postgra SQL
10:05:25and this will be like this. So posgress
10:05:27and then you have to give posgress your
10:05:29username your password and then you have
10:05:32to give your port. So do local host
10:05:36and this is running on 5440 right? So
10:05:40you're running on 5440. If you're using
10:05:42some different port you can use that.
10:05:44And then we are going to give that uh
10:05:46what is that name? So you're using more
10:05:48JS capstrong. So you're going to use
10:05:49this one. Okay,
10:05:52that's it. So now let's save this. And
10:05:54also it's I think you can also do this,
10:05:57right? You can also use underscore here
10:06:00if you don't want to use this one. I
10:06:01think that would be better. But it's
10:06:02fine. Uh so for now I think that's all
10:06:05we have to do this particular. So I
10:06:07wanted to mention couple of things. So
10:06:08the prerequisite for this particular
10:06:10section will be better. If you already
10:06:12know Docker that's fine then you can
10:06:14just continue or else watch that video
10:06:16that I mentioned. Second, install docker
10:06:18desktop and then you just have to create
10:06:20docker compos file and start the
10:06:22container. That's it. Now what we're
10:06:24going to do right so first let's go to
10:06:26our okay we are already here. So we need
10:06:28to understand that okay how many users
10:06:30we sorry how many tables we need first
10:06:32of all I'm pretty much sure you've
10:06:34already completed the postgress section
10:06:37right in the previous because if you
10:06:38don't do this one it will be tricky okay
10:06:40I highly recommend you watch that
10:06:42complete section do not skip that will
10:06:44be a game changanger for you because in
10:06:46that whoever completed you'll agree with
10:06:48me that I actually covered almost all
10:06:49the concepts if you haven't covered I'll
10:06:52suggest watch all the posgress topic and
10:06:54you'll see that how much easier it will
10:06:56be to complete this particular project
10:06:57So what we're going to do right we going
10:06:59to have one user table. Okay. Second we
10:07:02are going to have our support task table
10:07:04where we are going to store our support
10:07:06related task and then we are going to
10:07:08have our banners table. Banner means
10:07:10where we are going to do our upload or
10:07:12we are going to upload our images. Okay.
10:07:14What your uh this particular image uh
10:07:17user table is going to consist. User
10:07:19table is going to have your ID. So ID of
10:07:21that user. It is going to have the email
10:07:24of that user. It's going to have
10:07:26password hash. We are going to store
10:07:28password has. We are also going to have
10:07:31our Google ID, right? Because we also
10:07:33going to implement our Google login for
10:07:36this. And also we are going to have our
10:07:38role. Now role is very important because
10:07:40for this one we're going to have user as
10:07:42a role or this can be admin. Okay. So
10:07:45these two will be role and then we're
10:07:47going to have created and updated. So
10:07:49created will be when this user is
10:07:50created. If we are updating that user
10:07:52information when the user will be
10:07:54updated. So these all the things we
10:07:55going to have in our user table. What
10:07:57our support table is going to consist.
10:08:00This also will have the ID. So ID will
10:08:02be your primary key for this particular
10:08:04table. Then you're going to have the
10:08:05title of that uh support. Then you're
10:08:08going to have a status right. And then
10:08:10we are also going to have very very
10:08:12important we are going to have the user
10:08:13ID of that particular. So means which
10:08:17user actually creating this particular
10:08:18support. So this will be what? This will
10:08:20be a I think we have already covered
10:08:22this one. So we have primary key and
10:08:24foreign key. So this means this
10:08:26particular support task is created by
10:08:28this particular user. So that is that is
10:08:30an amazing if you completed the previous
10:08:32uh postgress section it will be way
10:08:34easier to understand each and
10:08:35everything. Okay. So these all the
10:08:36things we are going to have in this
10:08:37support table. Next we are going to have
10:08:40a banners. Banners is means where we
10:08:42going to store our ID. Now you might be
10:08:43thinking why we are doing all of these
10:08:46schemas at once. There is a huge reason
10:08:49and this is how you actually going to
10:08:51implement your own project because this
10:08:52is you take this one kind of a system
10:08:54design means before implementing the
10:08:56project you are actually checking your
10:08:58project scope how many tables what will
10:09:01be your relation all these things okay
10:09:03so that is the reason or else if we can
10:09:05also do this on step by step but I think
10:09:07this will be much easier okay so for
10:09:09banners we are also going to have the
10:09:10banner ID we are going to have the image
10:09:12URL image URL will be what so we are
10:09:15going to store the image to our client
10:09:17Cloudinary right so that we are going to
10:09:19discuss later and then cloudinary cloud
10:09:21is going to give you one particular URL
10:09:23and that URL we are going to store in
10:09:25our postgress we are also going to store
10:09:27one cloudinary unique ID and that
10:09:30particular thing we call as cloudinary
10:09:32public ID and you'll understand why
10:09:34actually we need this one and then we're
10:09:35going to have created and updated that.
10:09:37So these all the tables we are going to
10:09:39create. So first what we will do right
10:09:42so let's go to our codebase and let's
10:09:44create uh maybe so let's do outside only
10:09:47so I'm just going to do migrations okay
10:09:49now from this point everything will be
10:09:51very very important whatever we are
10:09:52going to do so first what will be the
10:09:54first file so first we're going to
10:09:55create our so let's give this one
10:09:57sequentially so I'll do enable and here
10:09:59we are going to enable our pg crypto um
10:10:02extension so I'll do enable pg so let me
10:10:05check the spelling so let's c r y p2 I
10:10:08think this is correct pg crypto And then
10:10:10we going to do let's do this one as um
10:10:12maybe let's do pgc crypto.sql. Okay. Uh
10:10:16here what we going to do? So we going to
10:10:17do create extension.
10:10:21Extension spelling is wrong. I think
10:10:23extension will be this if not exist
10:10:27right. And here we are going to do what?
10:10:29So we do pg crypto.
10:10:32If those who have already completed my
10:10:34posgress they already know why actually
10:10:36we need this one. Okay. So I'm not going
10:10:38to explain again. So do create extension
10:10:40if not exist PG crypto. Next we're going
10:10:43to create our user table. So I'm just
10:10:44going to do 002
10:10:47and I'll do create underscore I'll do
10:10:50users
10:10:52table.sql.
10:10:54So let's create. So I'm just going to do
10:10:56create table and here we're going to do
10:10:59users. Now first of all what we going to
10:11:02have? So we're going to have our ID. ID
10:11:04will be UU ID. And here this will be
10:11:06your primary key. And then we are going
10:11:09to have a default. And what will be a
10:11:11default? Default will be generate random
10:11:13ID. Remember we have actually covered
10:11:15this one also.
10:11:17That's it. Then we are going to have
10:11:20email. So email will be var. So let's
10:11:23give this one as 255
10:11:25not [snorts] null. And this also will be
10:11:27unique. Very very important. Next we are
10:11:30also going to have a password has. So
10:11:32I'm just going to take this one as
10:11:33password. Why breaking capital? So do
10:11:36password has and this will be text. Now
10:11:39very very important here when we are
10:11:42going to implement our Google login that
10:11:43time we don't need password has because
10:11:45Google is going to handle all of these.
10:11:47So that is the reason we are keeping
10:11:48this one as nullable. Okay. [laughter]
10:11:50Next we are also going to have our
10:11:52Google ID. So I'm just going to do
10:11:54Google id. So I'll do vare 255
10:11:58and I'm also going to do unique. Next we
10:12:01are going to do a role and I'll do vare
10:12:04and let's do 20 and I'll do not null.
10:12:09So let's take default. So what will be
10:12:11the default? By default we're going to
10:12:12create this one as user. So do user
10:12:15I'm just going to give a check
10:12:18and check let's give this one role. So
10:12:21I'll do ro in here I'm [snorts] just
10:12:23going to give two. So one will be either
10:12:25user or else this will be admin. Okay.
10:12:28So either it will be user or it will be
10:12:30admin. But by default this will be user.
10:12:32Then we are also going to have our
10:12:34created at. So I'll do created
10:12:37at created at time stamp.
10:12:41Uh let's do not null
10:12:44and what will be default? Default will
10:12:46be now. And the same thing we are going
10:12:49to do for updated also.
10:12:52So do updated at. So updated at this is
10:12:56also same. So this will be our first
10:12:58table. So you have ID, email of that
10:13:01user, password has, Google ID, RO,
10:13:03created at, and updated at. Okay. Next,
10:13:05we're going to have our third table,
10:13:07which will be our support table. So I'll
10:13:09do 003 underscore. So I'm just going to
10:13:12do create uh maybe let's do support.
10:13:15Let's do task. Now tasks and then I'm
10:13:19just going to do tablesql.
10:13:22So here we are going to do again. So
10:13:24I'll do create table.
10:13:26Uh let's do support
10:13:29tasks
10:13:31and here I'm simply going to do id u uu
10:13:35id uh this will be primary key this will
10:13:38be default and here we also going to do
10:13:41generate random key so go here and copy
10:13:44this
10:13:47next title where care uh how much maybe
10:13:51let's do 150 and let's do not null
10:13:56Then we're going to have a status. Now
10:13:58status we're going to take a var. So
10:14:00this will be 20 not null
10:14:04default uh let's keep a couple of status
10:14:07maybe default we'll keep open or else we
10:14:10are going to give a check property here.
10:14:14So you check and here what I'll do right
10:14:16I'll do status in uh let's give maybe
10:14:20open let's give one in progress in
10:14:23underscore
10:14:25progress and also I'm just going to give
10:14:28result so so you have three status okay
10:14:32uh what else very very important so
10:14:34you're going to have our foreign key
10:14:35which will be our user ID UU id so here
10:14:39we this will be not null definitely and
10:14:41what you have to use we have to use
10:14:42references Remember this we have
10:14:44actually discussed clearly in that
10:14:46posgress see I already mentioned
10:14:48everything everything whatever I'm
10:14:51mentioning that I'm that whatever you
10:14:53are seeing here right all are covered in
10:14:55the previous section okay so now here
10:14:58what you have to do is you have to give
10:15:00the user because see we are using user
10:15:02so user will be what will be your
10:15:04primary key primary key is ID now this
10:15:07is user ID okay so this will be your ID
10:15:10now we are going to do on delete
10:15:15cusk
10:15:17and then uh let's create created add
10:15:20timestamp
10:15:22not null and I'll do null and then we're
10:15:27going to have updated
10:15:29add timestamp not null null
10:15:35that's it
10:15:37so I think this is what we need and at
10:15:40the end we need our banners So now we
10:15:42will create one more. So I'll do 004
10:15:48create banners
10:15:51table.sql.
10:15:54So here let's create create table and
10:15:57here I'm just going to do banners.
10:16:00So first of all let's copy couple of
10:16:01things right. So this will be same.
10:16:04Then we're going to have our image url.
10:16:07This will be text and this also will be
10:16:09not null. You can't have empty image
10:16:11URL. Then we are going to have
10:16:13cloudinary public ID. Don't worry, we
10:16:16are going to actually cover all of this.
10:16:18Even I'll discuss the flow that how all
10:16:19all of this is working. For now, you
10:16:22consider this one as a unique ID that
10:16:24you need to interact with cloudinary
10:16:27something like this. And this will be
10:16:28cloudinary public ID and this will be
10:16:31text not null. Then we also going to
10:16:35take these two
10:16:38and then paste it here. That's it. So
10:16:41these four tables we need first of all
10:16:45not four three tables. One is our users,
10:16:48one is our support tasks and one is our
10:16:51create banner table. Now what important
10:16:53thing you are going to understand right?
10:16:55Because if you completed the postgress
10:16:57video you understand all of these what
10:16:58is happening. the thing that we are
10:17:00going to understand in the next part
10:17:01which will be how you can create your
10:17:03own custom migration and we are going to
10:17:05migrate the this particular schema in
10:17:07our posgress. So let's see how we are
10:17:09going to do that in the next part. All
10:17:10right. So now let's understand uh
10:17:13properly that how you can create your
10:17:14own custom migration script. So for this
10:17:17one what I'll do right go to source and
10:17:20create one more folder here and this I'm
10:17:22going to give this one as scripts and
10:17:24let's give this one as migrate.ts. Now
10:17:26if you want you can also keep this one
10:17:27in DB folder uh like DB then you can
10:17:30also do migrate.ts that is fine but we
10:17:33will use this only. Let's close
10:17:35everything else for now. Also before
10:17:38that we need to install one very very
10:17:40important package and that is we need to
10:17:42use something called PG. So PG package
10:17:44we are going to actually use to create
10:17:46to create our DB connection pool. Okay.
10:17:49Now you consider this one if you are
10:17:50familiar with right? So for
10:17:52what we usually use you use something
10:17:54called mongus right and then you'll do
10:17:56mongus doconnect and then you'll give
10:17:57your mongus mongodbd connection it will
10:18:00connect to your db remember in your code
10:18:03you need some medium right so that you
10:18:05will be able to query from your db so
10:18:07this is where we need one particular
10:18:09package and that package called pg okay
10:18:11because we're using raw posgress right
10:18:13raw pg we are not using any like prisma
10:18:17all these things right so if you want
10:18:19let me just quickly show you what I mean
10:18:20by this Chrome. Okay. So if I go here,
10:18:24right? So let's refresh this. So I'll do
10:18:26explain
10:18:28what's pg package is for posgress.
10:18:38So it's a official most popular
10:18:40low-level posgress client for your
10:18:42nodejs. Right? Postgress client is as I
10:18:44mentioned that you'll be able to create
10:18:46your connection pooling, right? you'll
10:18:47be able to query all these things
10:18:49whatever you need to do related to your
10:18:51uh posgress you'll be able to do that
10:18:54right so this is nothing but your client
10:18:56for your posgress in NodeJS similarly
10:18:58just just like you have Kafka JS for
10:19:00your Kafka client for NodeJS something
10:19:02like that so what you're going to do
10:19:04that we're going to install PG so copy
10:19:06this
10:19:08and then we will go here clear this and
10:19:11let's install this one first
10:19:14okay so this is added what I going to do
10:19:17right so first of all now you will
10:19:20understand another folder structure
10:19:22pattern now I already mentioned that how
10:19:24we are going to create the folder
10:19:26structure remember that whenever you
10:19:28will work with any config related thing
10:19:31you are going to keep this one inside
10:19:33your config folder when you are going to
10:19:35do let's say any DB related thing you
10:19:37can also keep this one inside your lip
10:19:39folder or the better will be you can
10:19:41create DB folder and inside this you can
10:19:43create something like that but you can
10:19:45also keep this one inside leave folder
10:19:47only middleware and all these things
10:19:49we're going to discuss later so for now
10:19:50what I'll do right so for now let's
10:19:52create here only so I'll do db ds and
10:19:54then first of all what we have to do so
10:19:56first I'm going to create on pool here
10:19:58const pool and this will be so first we
10:20:02need to do new and we are going to use
10:20:04this pool and this pool we are going to
10:20:06import from pg package so let's go here
10:20:09and then I'm going to import something
10:20:11from pg
10:20:13and this is going to give me I think we
10:20:14have to install the types uh Uh I think
10:20:16I always miss this. We need to also
10:20:18install the PG types also. Let's install
10:20:21this. Okay. So this is going to now I
10:20:24think it will not give you error. So
10:20:25just import and here what you have to
10:20:27pass right you have to pass the
10:20:28connection string. Okay. Now before that
10:20:31we also need to do one very very
10:20:33important point. Uh I'm not sure if you
10:20:35can recolct or if you can remember I
10:20:37mentioned whenever we are going to add a
10:20:38new env we also need to update our
10:20:41env.ts file that we have created inside
10:20:43config. So here what I'm going to do
10:20:45right we are going to create a helper
10:20:46function and let's do this one as check
10:20:49required env uh maybe let's do variables
10:20:53something env values or variables is
10:20:56better and here I'm going to check the
10:20:59uh string and let's return this one as
10:21:01string. So what I'll do right I'm just
10:21:03going to check the value and this will
10:21:05be process env.
10:21:09So this is going to give me value if
10:21:11there is not value present. So I'm just
10:21:13going to throw a new error. Okay. So
10:21:15I'll do throw new error and here we are
10:21:18going to do missing env variables for
10:21:22this variable for or then pass this key
10:21:26that this key is not present. And then
10:21:27what you have to do you have to note
10:21:29here outside return uh value. That's it.
10:21:34And then what you can do right because
10:21:35we need to add one more remember. So we
10:21:37are going to add our database C model.
10:21:39So do database C model. This database C
10:21:41model is the one that we have added just
10:21:43now this one. So do database C model and
10:21:45this will be now you can pass this and
10:21:47then here what you have to do you have
10:21:48to pass the value. So this will be our
10:21:51database model. So this is going to
10:21:52check this. Okay. So save this. Now
10:21:54we'll go to our db.ts and what you have
10:21:57to do right very very simple. Just
10:21:59import your env right. So you have envy
10:22:02cy that's it. So this is going to create
10:22:04your pool or connection pool and this is
10:22:07where this pool we can basically use to
10:22:09interact with our DV. Just think like
10:22:11that. So this is the first thing we have
10:22:12to do. Now we need to go to our
10:22:14migrate.ts and here you need to
10:22:16understand quite a few things and it's
10:22:18not that much simple. Okay. Uh so let's
10:22:21see how much simpler I can do. So first
10:22:24of all what you have to do right when
10:22:26you're creating a custom migration right
10:22:28because when you are a beginner I think
10:22:30this is more than enough also. I think
10:22:32that you should understand the custom
10:22:34migration first then you should use the
10:22:37third party packages because you have
10:22:39something called node pg migrate if I'm
10:22:41not wrong let me just show you right so
10:22:42do node pg migrate you'll see we have
10:22:44something like this
10:22:48uh see we have this node pg migrator so
10:22:51this is going to help you to m to
10:22:52migrate this one you can do this one
10:22:54right and also see here uh whatever blah
10:22:57blah but it's fine so you can pass this
10:23:00migrate you can do node p bracket and
10:23:01it's going to do the migration but we
10:23:03don't want to do this. Okay. What we'll
10:23:06do right we are going to migrate custom
10:23:08way. So how we are going to do that?
10:23:09First of all when you're going to do
10:23:11migration you need to understand where
10:23:12your migration folder uh stays right. So
10:23:15here now I'm going to pause this video
10:23:18and you have to understand that whether
10:23:20you can replay all the concept that we
10:23:21have learned so far. Remember in the
10:23:24path module in the core module you
10:23:25understood that how you're going to join
10:23:27your path how you're going to get your
10:23:29current working directory. remember so
10:23:31that will be your first step. So I'm
10:23:33just going to do con migration
10:23:35directory and this will be equal to your
10:23:38path. You're going to import from path
10:23:40node path dot join and you're going to
10:23:43get process dot cwd
10:23:47remember and then what you have to do
10:23:48you have to do migration. So this is
10:23:50going to give you the current working
10:23:52directory and then you have to go to
10:23:53migration. So here this is going to give
10:23:55you what? So this will give you your
10:23:57migration directory. So now this
10:23:59particular script we will understand
10:24:00okay this is where all my table stays.
10:24:04Okay
10:24:05next what we going to do right we are
10:24:07also going to create one particular
10:24:09table this migration table is going to
10:24:11track that which all file we have
10:24:14already migrated. So for example we now
10:24:17have three table consider later let's
10:24:19say we have added seven more tables. So
10:24:21it this particular table will understand
10:24:24that okay these three tables we have
10:24:26already migrated. So these three you
10:24:28don't have to do anything. Next seven
10:24:30new files we have to migrate. So for
10:24:33this one what we're going to do we're
10:24:34going to create a new create migration
10:24:39create migrations table. Okay. So this
10:24:41is what we're going to do the tracking
10:24:43now. So we can directly just use raqql
10:24:46here. So create table if not exist.
10:24:50Right. And I'm going to give migrations.
10:24:52Right. This is the name. And inside this
10:24:54what we're going to do. So I'm just
10:24:55going to use ID. Let's give this one as
10:24:58serial. This will be my primary key. As
10:25:00I already mentioned, see I've done all
10:25:02of these. You might be thinking how I'm
10:25:04writing first or this is first. You can
10:25:06pause or you can rewatch the same thing.
10:25:09I've done this all these things 100
10:25:11times. Once you'll do right, you'll
10:25:13understand all of these is nothing. It's
10:25:14very very simple. Okay. So here we're
10:25:16going to take name and I'm just going to
10:25:18do V care and I'll do 255
10:25:22not null and this name will be unique.
10:25:24Okay. So this name will be me and I'm
10:25:26also going to track that when this
10:25:28particular table is already migrated
10:25:30means when this is already executed. So
10:25:32do executed at. So we'll take this one
10:25:35as time stamp not null and let's take a
10:25:39default value and default will be now.
10:25:41I'm not sure if there is a spelling
10:25:42mistake. If I'm doing a spelling mistake
10:25:44don't blindly write. Just do if there is
10:25:46any mistake right just do it properly.
10:25:49But I think it's correct only. So create
10:25:51table if not exist migration ID name
10:25:53executed. That's it. So now what we're
10:25:56going to do right. So first of all let's
10:25:57do one thing. Let's create a function.
10:25:59One by one we need to do. So I'm just
10:26:00going to create async function. And here
10:26:04I'll do migrate. This one is going to
10:26:07return a promise of void. So first of
10:26:12all what I need to do? So first I need
10:26:15to create our uh migration table first
10:26:17because we need to create this table
10:26:19right. Then only we'll be able to track
10:26:20that which all migration we have already
10:26:22done. How you can do that? So first
10:26:24you're going to do like this. First I'll
10:26:26do a so you pull this just now created.
10:26:29So you can do query and then you're
10:26:31going to pass this create migration
10:26:32table SQL. Just now we have created.
10:26:35Once we'll do that now we have to find
10:26:39all the files inside this particular
10:26:41folder that are not yet executed. So
10:26:44that means if we can understand okay
10:26:46let's say this particular table is not
10:26:47executed. So we need to find this
10:26:49particular file. Okay. So that means
10:26:51what you're going to do right? So I'm
10:26:52just going to do con. Let's do executed
10:26:55and I'm just going to do new. So I'll
10:26:56take a set just just normal concept
10:27:00JavaScript concept. So I'll do set and
10:27:02then I'm just going to get all my
10:27:03executed migration that are already
10:27:05executed. So I'll do get executed
10:27:08migrations. You're getting what we are
10:27:10doing here. See everything we are doing
10:27:12I'm doing in that particular sequence so
10:27:14that it will be easier. So this get
10:27:16executed migration is going to give me
10:27:18all the migration that I've already
10:27:19done. So I'm simply going to do async
10:27:22function get executed migration. Uh
10:27:25let's do a promise and maybe let's
10:27:27return a string. So I'll do a string and
10:27:31of array. And what I'll do right so I'm
10:27:34just going to do con result.
10:27:37So this will be a so dot query. And here
10:27:41what we can do right we can also create
10:27:42a type. So just create a type directly
10:27:44here. And I'm just going to do migration
10:27:47row. And this will be so I'm going to
10:27:50take the name which will be string
10:27:52because I return string. So here I can
10:27:54pass this type. So I do migration log.
10:27:57Now what I'm going to do right so I'm
10:27:59going to actually uh query. So how we
10:28:01going to query? You have to write is SQL
10:28:04query. So I'll do select name. We
10:28:08already have name here. See we have name
10:28:10here. So select name from what is the
10:28:14table name. So table name is migration.
10:28:15So we'll do select name from migration
10:28:18and I'll do order by and order by name.
10:28:21Very very simple. We are not doing any
10:28:23like very complicated thing. We're
10:28:25simply getting the name from the
10:28:26migration table. And then what we'll do
10:28:28right it's going to give you a row. So
10:28:30I'll do result dot rows. So we're going
10:28:33to get rows dot map. So we're going to
10:28:35get current row which will be our
10:28:37migration row. This will this will only
10:28:39have name right because we're getting
10:28:41name here. And then what we're going to
10:28:43do simply going to return the row name.
10:28:46So this is going to already give me
10:28:48let's consider this that this migration
10:28:50table that you created already have this
10:28:52create user table. So that means by this
10:28:54particular function we'll understand
10:28:56that okay this particular table is
10:28:57already executed. So that will be our
10:28:59second step. Now if we found that okay
10:29:02these are executed. So we'll be able to
10:29:04see which all are pending. So I'll do
10:29:06get uh what I'll do right? We need to
10:29:09create one more file here. So let's do
10:29:11one thing. We also need to get all the
10:29:13migration file. So first I'm just going
10:29:15to create one more function and I'll do
10:29:17get all migration file that I need to
10:29:19migrate. So look get migration files. Uh
10:29:22and this will be string of array. And
10:29:24what I'll do right I'm going to return.
10:29:26So I'll import fs. FS I'm going to
10:29:28return from node fs. So I'll do import
10:29:32fs from node
10:29:36fs.
10:29:38So what I can do right so fs dot read
10:29:43directory sync and here what I'll do
10:29:46right I already have my migration
10:29:48directory so it will go to this
10:29:49particular path so I'm telling that okay
10:29:52go to this particular path no not
10:29:54migration migration directory then
10:29:56you're going to filter so here I'm
10:29:59simply going to take the file and this
10:30:01will be file dot and if you go here
10:30:05every file is ending with sql so what I
10:30:08can do right I'm just going to tell that
10:30:09okay if the file actually ends with
10:30:13SQL so dossql so that means now we'll
10:30:16understand okay for now because we
10:30:18haven't migrated anything so it will
10:30:20understand these 1 2 3 4 files I have
10:30:23correct and then what you can do right
10:30:24you can just do a sort here you can do
10:30:27sort
10:30:28so save this so this is going to give
10:30:30you all the migration file that you need
10:30:32to migrate now what you can do right you
10:30:34can just use this get migration files
10:30:37dot filter filter
10:30:39and this is going to give you the file
10:30:41and then you're going to check let's say
10:30:43we have four correct out of these two
10:30:46are already executed so now pending will
10:30:48be what four minus 2 correct so it will
10:30:50be two so we can filter it so it's
10:30:52simply going to do if this executed dot
10:30:54has this particular file means if this
10:30:57particular executed don't have this
10:31:00particular file that means that is not
10:31:01executed yet correct so that is painting
10:31:04it's normal JavaScript there is nothing
10:31:05related to any complicated thing we are
10:31:08doing if this pending.length length if
10:31:10this is zero so that means we don't have
10:31:12to do anything so we are going to get
10:31:14the logger dot info so I'm going to do
10:31:17no pending migration
10:31:22and then we going to return then we are
10:31:25going to do right now we going to
10:31:26actually run the migrations consider two
10:31:28are already pending so I'm going to do
10:31:30for so do con item no not item let's
10:31:33take file name of pending and then what
10:31:37we're going to do right here we are
10:31:38going to create our actual migration
10:31:40file. So we'll do run migration
10:31:43and here we're going to pass the file
10:31:45name. So this migration actually will be
10:31:47our main function where we are going to
10:31:49run the migration. So we'll go here and
10:31:51let's do uh this will be a sync function
10:31:56and I'll do run migration. So this is
10:31:58going to give me the file name
10:32:01which will be string and here this is
10:32:03also going to return a promise of void.
10:32:06Okay.
10:32:08All right. Right. So I'm going to pause
10:32:09this. I'm doing recording from long time
10:32:11and then we will resume from here. All
10:32:13right. So now let's implement the actual
10:32:15migration logic. Okay. So first of all
10:32:17what we going to do right? So first
10:32:18we'll get our uh SQL. So let's take a
10:32:22variable SQL. And then we are going to
10:32:23first read. So I'll do fs. Sorry this
10:32:26will be fs dot and I'll do read file
10:32:30sync. And what we're going to do we need
10:32:32to do path dot join. And this is where
10:32:35our migration directory will come. And
10:32:37then we're going to pass our file name.
10:32:39Okay. So this file name and then also we
10:32:42have to give the type which will be
10:32:44UTF8.
10:32:46So now what I'm going to do right so
10:32:48let's connect to our client. So have it.
10:32:51So we have our pool right. So created
10:32:54our pool uh and this will be pool dot
10:32:56connect.
10:32:58And now we are going to start try catch
10:33:03uh in the catch error. So here what I'm
10:33:06going to do right client and then here
10:33:09you can do a query and we're just going
10:33:11to pass a roll back here
10:33:15and here I'm just going to throw the
10:33:17error. So do throw error finally. So
10:33:20once everything is done
10:33:23so we are simply going to do what? So
10:33:25we'll do client dot release.
10:33:28Now in the try now first of all let's
10:33:30start. So look have it. So do client do
10:33:32query and we'll do begin.
10:33:37Now we are going to query the SQL. So do
10:33:39client do query create query this SQL.
10:33:44We'll do a client dot query and then
10:33:47we're going to insert. So do insert. So
10:33:49we need to insert each and every file
10:33:51once uh in this migration table so that
10:33:54we can keep a track. I think this part
10:33:55we've already discussed right. Right. So
10:33:57we going to do insert into
10:34:01insert into migrations
10:34:04and then we're going to do what? We're
10:34:06going to pass the name
10:34:08and here we're going to pass the values.
10:34:10So what will be values? So values here
10:34:11I'm just going to give. So the values
10:34:14will be this uh file name. Okay. So here
10:34:17you're going to pass the file name. So
10:34:19now this every time we're going to run a
10:34:21migration, this is going to actually
10:34:23post that particular file name into our
10:34:24migration table. Okay. And then we're
10:34:27going to just do commit. So do a client
10:34:29do query and we'll do commit.
10:34:33That's it. And let's take a logger do
10:34:36info. And I'm simply going to do
10:34:39migration
10:34:40completed.
10:34:44And let's pass the file name. Okay. So
10:34:46this is what we going to do. So this is
10:34:48going to actually run your migration.
10:34:50Right. So what we doing? So first we are
10:34:52checking what all are already executed,
10:34:54what all are pending. If nothing is
10:34:55pending, we don't have any pending
10:34:57migration. And then we are going to just
10:34:59uh check get or pending count for every
10:35:02file. We are going to run the migration
10:35:04and at the end what we can do right
10:35:06we'll do logger do info and I'm simply
10:35:09going to do all migrations completed
10:35:14and then here we're going to run the
10:35:16migration. So this migrate this one. So
10:35:18this is going to what return a promise
10:35:20right? So you can take a catch here. So
10:35:22I'll do a error. So there is any error.
10:35:26So what I'm going to do is I'll do
10:35:27logger dot error. And here we can pass a
10:35:31error and let's pass this error here.
10:35:33Okay. And also let's do a migration
10:35:36field something like this. Migrations
10:35:39field.
10:35:41And then what we can do we can take a
10:35:42process.exit and we can do a
10:35:45process.exit of one. This also we have
10:35:47already discussed. And let's take a
10:35:49finally. And the finally we just have to
10:35:53call this pool
10:35:55dot end.
10:35:58That's it. So this will be what actually
10:36:01we are going to uh implement our
10:36:03migration script. This is completely
10:36:05manual, right? We are not using any
10:36:06third party packages or anything. And
10:36:08I'll go to package.json. And then here
10:36:10we can add one more script. So I'll do
10:36:12migrate and then I'm simply going to do
10:36:15tsx source/
10:36:18So we have a scripts, right?
10:36:19webcripts/migrate.
10:36:23DS
10:36:24also if you want you can add some more
10:36:26uh script here. For example, let's say
10:36:28you wanted to add a docker up. So you
10:36:30can simply do docker compose up hyphen
10:36:33d. You want to take a docker down. So
10:36:36you can do do a docker down and I'm just
10:36:38going to do docker compose down. So we
10:36:42can just do all of these. So save this.
10:36:44Now let's see what is happening. Right.
10:36:46So we are going to do all right. So we
10:36:48run simply npm run migrate. Okay. So
10:36:50let's do this. I'll do npm run migrate.
10:36:55Okay. Getting some error. Syntax error
10:36:58near end. All right.
10:37:08Oh, we have to pass default here. We
10:37:11have to pass default here. And also
10:37:14let's give semicolon. And also I have
10:37:16checked one more issue is there. So this
10:37:17will be gen random id okay not get
10:37:21this is also wrong
10:37:24uh default we are using here so you need
10:37:26to use default let's see here okay see
10:37:29here also you're not using default so
10:37:30you have to use a default default value
10:37:36and also this will be len so now let's
10:37:40run it once again
10:37:42clear this
10:37:45fantastic so my is Now completed
10:37:47migration completed all migrations are
10:37:49completed. So that means now this is
10:37:52migrated this particular
10:37:55schemas and whatever table we have this
10:37:56is migrated to our posgress. So with
10:37:59this what we have understood till this
10:38:01part that you can also implement your
10:38:03own script or even create your own
10:38:05script for migration. You don't have to
10:38:07always use your third party packages
10:38:09right but again all these whatever you
10:38:12have written right these has to be
10:38:13precise it means you need to know all of
10:38:15these or if you don't have any idea
10:38:17right what why I'm mentioning all this
10:38:18one because don't learn any tech blindly
10:38:21for example let's say you don't have
10:38:23that much patience that okay you haven't
10:38:24watched the postgress part in the
10:38:25previous section and you directly
10:38:27watching this video some of the things
10:38:29will be very tricky for example let's
10:38:31say here only I made this mistake right
10:38:34I missed this one while writing but I I
10:38:36can guarantee some of you already was
10:38:38that party already catch it. Okay, there
10:38:40is default part is missing. you're
10:38:42getting what I'm talking about or maybe
10:38:44let's say this one also gen random ID
10:38:46right for example let's say if I wanted
10:38:48to ask you okay what actually this gen
10:38:50random ID is let me just refresh this so
10:38:53I'll do uh
10:38:55random ID in SQL
10:38:59now these whatever line that we are
10:39:01writing so gen random ID is going to
10:39:03build in postgress function generate u
10:39:05ID right here this also can be interview
10:39:08question now if you don't have any idea
10:39:09and blindly writing all of these then it
10:39:11will be difficult for you to understand.
10:39:13So that is the reason first prerequisite
10:39:15will be posgress and then we also
10:39:18understood that we are using docker
10:39:20compose. We created one simple uh
10:39:22service where we are using posgress.
10:39:24This is our env variables. This is the
10:39:26port where we are running. We have added
10:39:28this one in our env right. We have our
10:39:29database URL. We added the config uh
10:39:32this database URL. We have created our
10:39:34DB pool. And this is what we are going
10:39:36to use to query uh everything. So with
10:39:39this our base structure is now
10:39:40completed. What will be next step? Next
10:39:43will be we are going to actually start
10:39:44our CRUD and authentication. Each and
10:39:46every flow we are uh we are going to
10:39:48understand in very details. So let's get
10:39:51started. And also for this particular
10:39:52project we are going to use our own uh
10:39:55error handling. We are not going to use
10:39:57any third party packages like zord and
10:39:58everything that I will keep that
10:40:00particular part for our microservices
10:40:02video. So with this now let's move on to
10:40:04the next one. All right. So first let's
10:40:06create one more folder here and here I'm
10:40:08just going to give this one as errors.
10:40:10Okay. And inside this, let's create one
10:40:12app error. DS. So this is where we're
10:40:16going to actually handle our error. So
10:40:18I'm just going to do export class. This
10:40:21will be simply app error. And this is
10:40:23going to extend our error. Okay, error
10:40:26interface. What we going to do? We are
10:40:28going to have a status code. And this
10:40:30status code will be number. And now I'll
10:40:33simply take a constructor. And here what
10:40:36we going to do, right? We're going to
10:40:37take our status code which will be
10:40:39number. And also there is a possibility
10:40:41that we are also going to send send one
10:40:43uh message whenever it's needed. So now
10:40:46we going to p take a super pass the
10:40:48message and then I'm simply going to do
10:40:50this dot status code will be equal to
10:40:52the status code that we have. That's it.
10:40:54And we don't have to do anything where
10:40:56we are going to use this particular uh
10:40:58error class. So we're going to use this
10:41:00one in our error handler. Remember we
10:41:02have created this error handler. This is
10:41:04what we are going to do. Now if you
10:41:05notice what we are simply doing, we have
10:41:07error here. request response blah blah
10:41:09whatever and at the end then we are
10:41:10sending this response back. What we need
10:41:12to check that if this particular error
10:41:15that we have if this is a instance of
10:41:18this app error. So in that case what we
10:41:20can do right we don't have to pass
10:41:22always some success false and message uh
10:41:25whatever it is why in this case what we
10:41:27can do right we can directly get our
10:41:29error dot status code also okay and also
10:41:32we going to get our message so what we
10:41:34going to do right simply to use this I'm
10:41:37simply going to do if this error
10:41:38whatever error that we have if this
10:41:41error is instance of the app error that
10:41:43we have created our custom error so in
10:41:45that case I'm simply going to do race
10:41:47dot status and this will error dot
10:41:50status code. So you can see that you're
10:41:51getting error dot status code dot JSON
10:41:54and then you can do a success will be
10:41:57false
10:42:02and we are going to pass message which
10:42:05will be error dot message right so now
10:42:08this will be a custom way that we are
10:42:10handling the error okay so now what you
10:42:12can do that whenever we need to use this
10:42:14let's say I'm going to pass a new app
10:42:15error and then we're going to pass a
10:42:16status code correct and the message so
10:42:19it's going to let's say something
10:42:20breaks. So it will check okay the
10:42:22currently the error is the instance of
10:42:24app. So it's going to send this one and
10:42:26this error handler we are actually using
10:42:28in our app. DS okay so this is how it's
10:42:31going to work. So this is the first
10:42:32thing we have to do. Now what will be
10:42:34the second step? Second step will be now
10:42:37before we will start writing let's
10:42:39understand that how that actual flow
10:42:41will work. It will be easier. Uh let's
10:42:43use this one. See first of all we have
10:42:45to understand understand that okay how
10:42:47this flow will work. So let's say you
10:42:48have a register and you have a login
10:42:51right. So how register will work? So
10:42:53let's say you have a email right
10:42:54consider you have a UI you have a email
10:42:57you have a password correct? So this is
10:43:00your password and then you have one more
10:43:02button and this is like continue with
10:43:06Google. Now you'll see that this
10:43:08particular thing you are going to see so
10:43:10many places. So that means we are giving
10:43:13user options that either you can
10:43:14register using email and password or so
10:43:18here I'm going to do or you can register
10:43:20directly using Google. Now this Google
10:43:22part we are not going to do now okay and
10:43:24there is a reason for this because this
10:43:26will be little tricky because you need
10:43:28to know the concept of all three direct
10:43:30call back and all those things this one
10:43:32we're going to do later. Okay first we
10:43:34have to understand that how this flow
10:43:37will work. So when we are going to do
10:43:38email and password so user will enter a
10:43:41email. So first of all we need to check
10:43:42if the email format is correct or not.
10:43:44If this is a valid email or not. So that
10:43:47is the first thing. Second we also going
10:43:49to check whether user entered the
10:43:51password or not. So that is the very
10:43:52basic validation. If user don't enter
10:43:56email or password we are going to send a
10:43:58error back. Okay. So that is the first
10:44:00thing. Second we need to check if the
10:44:02email is a valid password. Sorry email
10:44:04is a valid email. Second, if the
10:44:06password format is valid or not. So
10:44:08let's say I need at least six characters
10:44:10in the password. But when user is
10:44:12giving, user is giving 1 2 3 4 5
10:44:15characters. So that means this condition
10:44:17is not satisfying. So in that case we
10:44:19are also going to throw an error. Now
10:44:21once registration is completed, so once
10:44:24this is completed, we will not redirect
10:44:27the user to our application. Now this is
10:44:29actually very important. Why? What we
10:44:31are going to do right? Once registration
10:44:33is done, we will simply mention user.
10:44:35Okay, registration is completed. Okay.
10:44:38Now what we have to do? You have to log
10:44:40to enter into application. Why? Because
10:44:43directly we are not going to do that. Uh
10:44:45and now remember one thing, there is so
10:44:47many things we can do here. You can
10:44:48implement a two-step verification. You
10:44:50can send email and know those things.
10:44:51But I'm not going to do all of this. I
10:44:53already have a separate video for that
10:44:55also. If you want you can check all of
10:44:56this. I think there is no point of
10:44:58adding each and everything in this
10:44:59particular project. So if you if you're
10:45:02not sure I okay you can go to my channel
10:45:05and just search for sangamukhari nodejs
10:45:07security and those things and you'll see
10:45:08that you are going to get all of these
10:45:10okay but what I'm trying to say that
10:45:11after register we will not allow the
10:45:13user to enter into our application once
10:45:16registration is done user needs to login
10:45:18and once you're going to do login what
10:45:20will happen so user will again give
10:45:21email user will again give password if
10:45:24user is giving wrong email or wrong
10:45:25password we'll simply say that okay your
10:45:27email is wrong password is wrong once
10:45:30they will give correct credential what
10:45:32we're going to do right we're going to
10:45:33create a token and this token we call as
10:45:36JWT right so this will be our JWT token
10:45:39what this JWT token is going to hold
10:45:42this token is going to hold this
10:45:44particular user information so user
10:45:46information what user information so
10:45:49here in this using this JWT token we
10:45:52will be able to verify whether this user
10:45:54is a correct user or not so consider we
10:45:56have a user A and user B so the JWT
10:46:00information of this user A will be
10:46:01different. The JWT token of this user B
10:46:04will be different. This user JWT is will
10:46:07be holding user A information, this uh
10:46:10user BJ JWT is going to hold user B JWT
10:46:14information. Right? So that means when
10:46:16let's say if user B try to access user A
10:46:19account, it's not going to happen.
10:46:21Correct? You're getting what I'm talking
10:46:22until unless this user know the password
10:46:25of this particular user. So that is the
10:46:27reason we have something called JWT
10:46:29right JWT is going to give our uh
10:46:32capability to check whether that
10:46:34particular user is a valid user or not.
10:46:36So first of all what we're going to do
10:46:38is we'll be implementing our register
10:46:39flow. Once user will register user will
10:46:42go to login. Once user will login then
10:46:45we're going to create our JWT token.
10:46:48Once they will create the token then
10:46:49we're going to create our middleware.
10:46:51Now this is where you are actually going
10:46:53to implement uh or understand one very
10:46:55important concept that is middleware. So
10:46:57now what are we going to do right? So
10:46:59first let's start with the register
10:47:00first and then we'll go to medial
10:47:02because this is one of the most
10:47:03important thing you have to understand
10:47:05right how you can implement uh protect
10:47:07routes or how you can protect routes. So
10:47:10one will be protection of routes and
10:47:11second something called rolebased access
10:47:14control. Now this is actually rolebased
10:47:16access control. So this is actually very
10:47:18important. Okay. So let's uh start with
10:47:20the register
10:47:22logic in the next part. Okay. So we'll
10:47:24start implementing our register and
10:47:26login flow. Correct. So first let's go
10:47:28here. And now here also you are going to
10:47:31understand now how you can create proper
10:47:33folder structure practically. Right. We
10:47:35will have now more practical code
10:47:36implementation rather than only
10:47:37concepts. So let's create our first
10:47:39folder which will be types. Types will
10:47:41be one folder where you're going to keep
10:47:43all your TypeScript types. As simple as
10:47:45that. In our case because in register
10:47:47and login flow we are working with user.
10:47:50So we are going to create our first type
10:47:52which will be user.ts.
10:47:54So now let's close everything else. So
10:47:56what this is going to have this is only
10:47:58going to have your user type. So we do
10:48:00export type and I'm just going to give
10:48:02user. So user is going to have your ID
10:48:04which will be string. User is going to
10:48:06have your email which will be string.
10:48:08User will be having your role which will
10:48:10be string. And also it's going to have
10:48:12your created. Now remember these all we
10:48:14already have here, right? say uh id uh
10:48:17this id email created at all this. So
10:48:20here also we're going to take created
10:48:23add and this will be date. Okay. So this
10:48:26is the first thing we are going to do.
10:48:28Now you have to understand one very
10:48:30important point that how the actual
10:48:32folder structure works. So need to
10:48:33understand this one in three parts.
10:48:35Okay. So first one
10:48:38or let's do like this. So this is
10:48:41consider this is your root file. This is
10:48:43your root file. I'm going to keep our
10:48:45root. What I mean by root file? Root
10:48:47file is your app.ts. Consider like this
10:48:49this one. Correct?
10:48:51Now this root file is going to hold all
10:48:55the information of your code. Correct?
10:48:57What you're going to do right? Normally
10:48:59we usually divide this one in three main
10:49:01files. One file we called as repository.
10:49:04So I'm going to call this one as repo.
10:49:06Second one we call as our services. So
10:49:10services is our where business logic
10:49:12we're going to keep. And third will be
10:49:13our actual routes and this routes file.
10:49:16So this will be your routes and then
10:49:18there will be your root routes file.
10:49:20Root route root routes file. Now this
10:49:25might be little tricky. So let's
10:49:26understand first of all what actually
10:49:27repository is. Repository is going to
10:49:29hold or repository will be responsible
10:49:31for writing all your DB related logic.
10:49:35DB related logic means whenever you need
10:49:37to interact with your post DB. So in
10:49:40that case you are going to write all
10:49:42those logic in your repo. You are not
10:49:45going to write your service logic in
10:49:47your repository file. Okay. Repository
10:49:49means you will only interact with your
10:49:51DB. What your service logic? Service
10:49:53logic is going to actually hold your
10:49:54business logic. For example, let's say
10:49:56you want to implement some validation.
10:49:58You want to implement some extra logic.
10:50:00You are using some helper function.
10:50:01You're creating your JWT token. All
10:50:03these things okay that is going to hold
10:50:05your service logic. And this is not
10:50:07about only register or login flow. This
10:50:09will be for all the logic that you're
10:50:11going to write. And what your route
10:50:13information is going to hold? Route
10:50:14information is going to hold your actual
10:50:16routes based on that particular feature.
10:50:19What I mean by based on that particular
10:50:21feature, let's say you have a O feature
10:50:23and you have a CRUD feature. So there
10:50:25will be two file. One route file will be
10:50:27for O, one route file will be for uh
10:50:30CRUD. And then these two routes you are
10:50:33going to combine. So these two routes
10:50:35you're going to combine in your root
10:50:37route file. Correct? So root route I
10:50:39think we have already created. Root
10:50:41route means this route. So this is where
10:50:43you are going to have all your routes
10:50:45and this route file you're going to use
10:50:47in your main entry file. Right? So this
10:50:50will be the flow. So that means now in
10:50:52our case what you have to create we have
10:50:54to create couple of folders. So first
10:50:56I'm going to create repository.
10:51:00Then we're going to create services.
10:51:03Then we have routes which we already
10:51:06have. Correct? So first let's start with
10:51:08our uh repository. So here I'll go to
10:51:11repository.
10:51:13Where is repository? So here I'm just
10:51:15going to create user dot. So I'll do
10:51:18repository
10:51:20dot ds. Okay. So this is where we are
10:51:24going to actually have all your DB logic
10:51:26in this particular file. Then you're
10:51:28going to have a services. Services means
10:51:30where we are going to add our actual
10:51:32services logic. Okay. All right. Sorry I
10:51:34need to pause because of some noise.
10:51:35Okay. So what I was talking about right
10:51:37so in the services we're going to write
10:51:38actual business logic. Okay. So first of
10:51:40all let's create our o service. So I'm
10:51:42just going to do o dot service.
10:51:45Yes. Now normally in my other videos
10:51:46what I do right I usually come from like
10:51:49a [snorts] reverse way means I'll
10:51:51implement the repository and services
10:51:52and the then routes but let's do in this
10:51:55particular video I'm going to do much
10:51:57better way. So what are we going to do
10:51:58right? You are going to understand the
10:51:59these concepts uh very very clearly. So
10:52:02now so we already have used the
10:52:03repository o service and now we'll go to
10:52:06our routes and let's create our o routes
10:52:08and you'll see that how much easier it
10:52:10will be for you to understand all this.
10:52:13So what you're going to do right first
10:52:14of all let's import routes okay so sorry
10:52:16router
10:52:18so I'm going to import router I think
10:52:20these we have already discussed and now
10:52:22I'll do export const
10:52:25router and this will be about this
10:52:28router make sense what you're going to
10:52:31do right so if you go here right you see
10:52:33this part this particular file is going
10:52:36to hold all your routes I already
10:52:38mentioned so what you're going to do
10:52:40first of all let's do reverse way so I'm
10:52:42simply going to do here okay app router
10:52:45sorry API router dot use and then I'm
10:52:47simply going to tell that whenever I
10:52:49will go to this o route so this will be
10:52:52my parent route okay / will be the
10:52:54parent route for all our o related
10:52:57routes now this might be little tricky
10:52:58so what I mean by this let's say in your
10:53:00o routes file you have five routes one
10:53:03is /register one is / login right like
10:53:08this so what will happen when I'm using
10:53:10/ so now this will become/ / o/register/
10:53:14o/ login/ o/me whatever right so this is
10:53:18my parent route this is my parent route
10:53:20for my o and this is where I'm going to
10:53:23use my o router now for now this is not
10:53:25going to work okay even if I save this
10:53:27this is going to give me error uh that
10:53:29okay something is breaking and whatever
10:53:31that's fine but now let's go here so
10:53:33first of all we created our o router we
10:53:35have plugged this o router in our root
10:53:37router that's it now what I have to do
10:53:39right so in this o router first we have
10:53:41to decide that how many routes we need
10:53:42to have. So for now let's start with
10:53:44register only first. Okay, we'll do one
10:53:46at a time. So do all route dot post. So
10:53:50now this will be my register. So this
10:53:51will be my register route. This will be
10:53:53my path that I need to give. And then
10:53:55I'm going to have my async. So I'll do
10:53:58request response. And here I'm simply
10:54:01going to have next.
10:54:05And inside this now first of all you
10:54:07need to do always try and catch. The
10:54:10first thing what you have to understand
10:54:12here. So I'm just going to take catch
10:54:14error and then whenever there is error
10:54:16what I'm going to do right I'm going to
10:54:17call this next and I'm going to pass
10:54:20this error to our next middleware. Okay
10:54:23so this is always going to check it
10:54:25because we are already using it uh using
10:54:27this in our app.ts TS right you'll see
10:54:29that we have this error handler and all
10:54:31of these you remember that part we have
10:54:32checked that even if you try to send any
10:54:34route which is not present so this not
10:54:37found is always going to catch it and
10:54:39it's going to understood okay this route
10:54:40is not present so I need to return a 404
10:54:42something like this so this will be the
10:54:44first thing in this try what I need to
10:54:46do now here we have to understood uh
10:54:49sorry understand some of the very
10:54:50important thing that when user is going
10:54:52to send your email right and password so
10:54:57this will be where this will be in your
10:54:59UI correct UI means where user will be
10:55:01actually typing these values but in your
10:55:03back end how we going to get these
10:55:05values so this is where we have
10:55:06something called request so the request
10:55:09is going to give you this body so
10:55:11request do body so this request do body
10:55:14is going to hold your email and password
10:55:16information that you are going to
10:55:18receive here so I'm just going to do con
10:55:20and this will be my request do body so
10:55:24you'll see that we have this request do
10:55:25body this is going to have all your
10:55:27information that you're going to pass
10:55:28because you're using a post request and
10:55:30this is what I'm going to get email and
10:55:32password right because for now we have
10:55:34only email and password now let's say
10:55:35you have name also so in this case you
10:55:37also take name let's say you have age
10:55:39also you're going to take this you have
10:55:40address also so whatever you are going
10:55:42to send from your UI side you're going
10:55:44to get it from your request do body so
10:55:46for now we have only email and password
10:55:49that's it and now what we going to do
10:55:50right we are not going to write so do
10:55:53not or not writing
10:55:56service logic here right service logic
10:55:59here so service logic will be in service
10:56:02logic in service file right so service
10:56:04file and now this is where I'm going to
10:56:06create so I'm going to create our first
10:56:08service and this will be my register
10:56:11user and this is where I'm going to pass
10:56:13this email and the password okay and
10:56:16then once this service logic is
10:56:18completed what we need to do we need to
10:56:20send back the response back to our UI
10:56:22right because if you don't send back how
10:56:24your user is going to understand that
10:56:27okay if my register is successful or
10:56:29something goes wrong so that means
10:56:30always you need to send your status back
10:56:32so what will be status because you are
10:56:34creating something remember you are
10:56:36creating user so in this case you can't
10:56:37use two 200 you have to use 201
10:56:41status code we usually use for create
10:56:43okay and then you'll do JSON if you just
10:56:46do write see 200 versus 2010
10:56:55okay means request succeeded two 201
10:56:57created means and end request succeeded
10:56:59and brand new resource was successfully
10:57:01generated on the server. So in this case
10:57:02we're creating a new user correct so
10:57:05it's a create so that's why you're using
10:57:07201 and this will be JSON so we going to
10:57:10pass a success we'll keep this one very
10:57:12simple main idea is to so that every
10:57:15student every level of student can
10:57:17understand what we are doing here so
10:57:18it's simply going to do registration
10:57:20successful and then we are going to do
10:57:23like this see please login to continue
10:57:25that means you can't get into our
10:57:27application yet you have to login then
10:57:29only you can continue so this is Done.
10:57:31Save this. Now this is going to give you
10:57:33error. That is fine. Now we'll go to our
10:57:36service file. So go to service file and
10:57:38this is where we're going to create our
10:57:39first service. So what will be our first
10:57:41service? I'm just going to do export
10:57:42async function and we're going to use
10:57:45this register. See I'm going to repeat
10:57:47one thing only the register user. I'm
10:57:49doing very very slowly from the next
10:57:51time I'm not going to explain each and
10:57:52every line. This video will be already
10:57:54very long, right? Because some of the
10:57:57things will be repeated. You'll see
10:57:59that. So we have email and this will be
10:58:01string and then we have a password this
10:58:04also will be a string right because
10:58:06these two we are receiving correct where
10:58:07is that we're receiving email and
10:58:10password what's this is going to return
10:58:12so we're going to return a promise and
10:58:14this will void now first of all what we
10:58:17going to do we going to check simple
10:58:18validation do if email is not present or
10:58:21if password is not present now you see
10:58:24what we're doing throwing new app error
10:58:27this is very very important because Now
10:58:29everything you're creating manually
10:58:31you're not using any third party
10:58:32package. So what I'm doing I'm simply
10:58:34using this app error here. So I'm
10:58:36calling this app error and similarly I'm
10:58:37telling that okay I have to pass a
10:58:39status code. So my status code will be
10:58:41400 because it's something goes wrong
10:58:43and then I'm going to pass message that
10:58:45either email and password are required.
10:58:47Email and password are required. Now
10:58:50what will happen? This app error is
10:58:51going to catch it and then in your error
10:58:54handler you are simply telling that if
10:58:55this error is a instance of app error.
10:58:57So you're going to return this. you're
10:58:58getting what I'm doing. So this message
10:59:00error dot message is nothing but this
10:59:02message that we are going to receive. So
10:59:04this is the first thing then I'm simply
10:59:06going to check if my password dot length
10:59:09right if this is less than mean password
10:59:12length. So for example let's say I'm
10:59:14just going to give mean password length
10:59:15as six. Okay. Now here I'm going to give
10:59:17a homework. Now this is not a homework
10:59:19but simpler. What you can do right
10:59:22create one more folder
10:59:25called constants
10:59:28and keep this six value 61 six in a
10:59:33constant and use this here you're
10:59:37getting what I'm talking about so that
10:59:38means you'll create one more folder here
10:59:40constant keep this one in a constant
10:59:42like maybe minimum password length
10:59:44something like this and then use it here
10:59:46so that you'll also uh you will be also
10:59:49able to understand that okay what we are
10:59:50doing and when next time you're going to
10:59:53create project you'll know that okay
10:59:54what each and every folder means so here
10:59:57also I'm going to throw new app error so
11:00:00I'll give a 400 and I'll simply do
11:00:02password
11:00:04must be at least six characters long
11:00:11that's it
11:00:13going to do right I'm going to do con
11:00:15and I'm just going to do normalize email
11:00:17so I'm just going to do email whatever
11:00:19email and I'm just going to do two lower
11:00:21case. So two lower case and then I'm
11:00:23going to do a trim here. This is normal
11:00:25concept. Now what we have to do first of
11:00:29all you'll see that when you are
11:00:31registering a particular user let's say
11:00:32one user email is John at the
11:00:36redgmail.com. This user is already
11:00:38registered. Okay. Next time let's say
11:00:41there is one more user is coming B and
11:00:43this user is using same email this
11:00:45Johntheregmail.com. So what will happen?
11:00:48should not happen right because there
11:00:49will be only one user with unique email.
11:00:52Next time if you allow user to register
11:00:55with the same email so there will be two
11:00:57user with same email and you don't even
11:00:59know whether that is a user A or that is
11:01:01a user B. Right? So that means first of
11:01:04all we we have to check that if this
11:01:06current email that whatever user is
11:01:08sending if this email is already present
11:01:10in our DB or not. So that means you have
11:01:13to find the user if it's present if it's
11:01:17already present in DB or not. If it is
11:01:22present if yes then we'll not allow we
11:01:24will not allow to register with same
11:01:29email again. That's it. Right? That's
11:01:32it. So this is actually very very
11:01:34important especially for
11:01:37um beginners. Right? So this we have to
11:01:39know. So first we need to know here
11:01:43existing user correct. So we do existing
11:01:45user and now I'm just going to do a and
11:01:47this is where now we have to use our
11:01:50repository because how you're going to
11:01:51understand if this is existing user you
11:01:53need to check in your DB correct so that
11:01:55means I what I mentioned that whenever
11:01:56you need to do something with DB so that
11:01:59means you have to write that particular
11:02:02logic in your user repository means in
11:02:04your repository file. So first of all
11:02:06what are we going to do right? So let's
11:02:08go to our types and I'm just going to do
11:02:11export type and I'm just going to do uh
11:02:15DB DB user row. So DB user row is
11:02:20nothing but in which format or in which
11:02:23format you are actually storing the user
11:02:25in your DB. So this will be same only
11:02:27with this. Okay. So this DB user row is
11:02:30nothing but what all properties that you
11:02:32have in your DB. Okay. So we'll go here
11:02:35and also we need one more type here that
11:02:37we are going to use later. So I'm just
11:02:38going to do export type and let's do DB
11:02:42user with password
11:02:47and this will be your DB user and and
11:02:50here we are going to have what when
11:02:52you're going to have password so you're
11:02:54also going to have this password has
11:02:55this we going to use later. So this will
11:02:57be either string or null but for now I
11:02:59think this is fine. So now what you can
11:03:01do that we'll go to our user repository
11:03:03and this is where I'm just going to
11:03:04first check that find
11:03:07user by email because in our o service
11:03:10we need to check that if this user is
11:03:12present or not you're getting so first
11:03:15I'm simply going to check that find
11:03:19user
11:03:21uh let's keep by email what you have to
11:03:24pass you have to pass this normalized
11:03:25email this one so this method now we are
11:03:28going to create in our user repository
11:03:30So I'm simply going to do export as sync
11:03:33function
11:03:36find user by email. So here we are going
11:03:39to get the email which will be string
11:03:41and here what we're going to do right we
11:03:43are simply going to get promise what
11:03:46will be the return type return type will
11:03:48be user this user will be in our type
11:03:52now okay one thing I I think I should
11:03:54mention don't get confused with this so
11:03:56you might be thinking if both are same
11:03:58why why you are creating two separate
11:04:00this is the format how we are storing
11:04:01the user in your DB this is the format
11:04:04how you want to return the data for
11:04:05example let's say you have one more
11:04:07something like this first name and this
11:04:10first name you want to return like this
11:04:12but in your DB this first name is
11:04:14present like this you're getting so
11:04:16these both are different so that is the
11:04:18reason we taking uh different type so
11:04:20that for now it is same but in some
11:04:23cases this will not be same
11:04:26so now there will be some snake case
11:04:27camel case all those things right so
11:04:29this is how we are going to return so
11:04:30either it will be user or it will be
11:04:33null and now what I'm going to do right
11:04:35I'm simply do const
11:04:37get the result. So result will be a we
11:04:40need to get our pool because this is
11:04:41where we are going to query. So you pull
11:04:43dot query and now this is where you have
11:04:45to give the type. This type will be your
11:04:47DB user row. This is how we are storing
11:04:49you're getting. And now we are going to
11:04:51write our SQL query. So I'm simply going
11:04:53to do select
11:04:58ID. And believe me or not, I usually
11:05:01like writing these raw queries so much.
11:05:03Okay? because I always believe that
11:05:05these all are much easier to understand
11:05:07and also it will give you very strong
11:05:08foundation. So I need ID email or so
11:05:11sorry this will be ro and created at
11:05:13from where from my user table. So I'm
11:05:15just going to do from my user table
11:05:17where what where the email is this
11:05:19right? So where email is equal to dollar
11:05:22one and this is where I'm going to just
11:05:24simply pass our email. So this is now is
11:05:27going to return this whether this user
11:05:30is present or not. And then I'm just
11:05:31going to do read result dot rows. I only
11:05:34need the first one or else it will be
11:05:37null. That's it. So now this is going to
11:05:40tell if this user is already present or
11:05:42not. So I'm going to import this. That's
11:05:44it. So what will be our next step? Once
11:05:47this is done, first we also have to give
11:05:49that if this existing user is already
11:05:51present. So in that case we're going to
11:05:52throw a new error. I think I already
11:05:54mentioned that we're going to throw a
11:05:56new app error and I'm simply going to do
11:05:58409 and I'll say that email already
11:06:02present. You're getting what are you
11:06:03doing that you can't use same email
11:06:05again.
11:06:07Once we'll do that now next time when
11:06:09we're going to give email and password
11:06:11right so let's see user given password 1
11:06:132 3 4 5 6 7 8 like that you never store
11:06:17this raw password in your DB okay should
11:06:20not do that what you have to do you have
11:06:22to create encryption or we usually call
11:06:24that one as has I think this part you
11:06:25already discussed in the crypto module
11:06:28so we need to create a password hash we
11:06:30are not going to store raw password in
11:06:33our DB correct but how we are going to
11:06:34do that this is where we need to inst
11:06:36install our b-rypt package. So brypt is
11:06:39a package that will give you that uh
11:06:41feature to hash your password. Okay. Uh
11:06:45so I'll just do give this one. Give me
11:06:46npm install bcrypt give me types uh npm
11:06:51also types brypt also.
11:06:59Okay. So these two things we need. So
11:07:00let's install npm install bcrypt js. You
11:07:03can use something called argan. So there
11:07:05is argon but brypt is actually very
11:07:07popular. So that is the reason uh we are
11:07:09going to use this. So npm install bcrypt
11:07:12and also need the types. So we'll copy
11:07:14this
11:07:16and I'm simply going to do types.
11:07:19So now what are you going to do right?
11:07:20So here I'm going to create a password
11:07:22has. So I'm just going to do con
11:07:24password
11:07:26has
11:07:29and this will be ait. So here what I'm
11:07:32going to do is let's uh sorry we have to
11:07:34import our brypt. So I'll do import
11:07:36bcrypt from brypt
11:07:40js
11:07:44and here I'm just going to do brypt and
11:07:46this is going to give you h has and here
11:07:48you have to pass the password. So
11:07:49password will be which password? The
11:07:50password that you are receiving this
11:07:52password. So you're going to pass the
11:07:53password here and then you have to pass
11:07:55a salt. Okay. Now in this case again
11:07:58what you can do right for now I'm just
11:07:59going to give direct as 10 but what you
11:08:01can do you can move this one to a
11:08:03constant file just like I mentioned here
11:08:05okay and this is done and then what
11:08:07you're going to do right now we are
11:08:08going to simply create the user now this
11:08:11create user is going to do what it's
11:08:12going to actually store your user in
11:08:14your DV so I'm simply going to have it
11:08:16and I'm simply going to do create user
11:08:19right create user and this is where what
11:08:23you have to pass you have to pass the
11:08:24normalized email and your password has
11:08:26both and this create user where you have
11:08:29to do it pause it and try to guess again
11:08:33you are doing something with your DB so
11:08:35that means you have to do in your
11:08:36repository so now if you go here and
11:08:39let's create one more so I'm simply
11:08:40going to do export as sync function and
11:08:44I'll do create user this is where we're
11:08:46going to get the email which will be
11:08:48string we're going to get the password
11:08:51has
11:08:53this also will be string and Now we are
11:08:56going to simply uh this will be type
11:08:58will be promise of user.
11:09:01So now I'm simply going to do con result
11:09:04this will be a pool dot query
11:09:08pass out db user row and this is where
11:09:11you're going to write our uh query.
11:09:14Okay. So I'm simply going to do insert
11:09:18into what is a table users. What we have
11:09:21to insert? You have to insert email and
11:09:23password
11:09:25has right. So your password has.
11:09:30So you have a values
11:09:37and then we are also going to do a
11:09:39returning here
11:09:42email ro and also let's return the
11:09:44created at that's it. And what will be
11:09:48the values? values will be your email
11:09:50and your password has. Right? Because
11:09:52we're passing email and password has.
11:09:54That's it. And then you're going to
11:09:55simply return
11:09:58result dot rows of zero. And this is
11:10:03done. Okay. So this will be your query.
11:10:08I think there is extra that's fine.
11:10:10Let's remove this line.
11:10:20Okay, let's keep it like this only. Save
11:10:22this. So now, [snorts] oh no, I don't
11:10:24like this one. Let's keep it like this.
11:10:34And we can move this one here
11:10:37like this. Okay, so this is fine. And
11:10:39now what we can do, right, we'll go to
11:10:40our o service and we'll just import it.
11:10:45Done. Go to what routes and then import
11:10:48your register user. That's it. And now
11:10:50save this and you'll see that now you
11:10:52should not get any error here.
11:10:56Okay, let's save this. Let's run it once
11:11:00again.
11:11:01I'll clear this and I'll do npm rundev.
11:11:05It's running. Okay, so now let's go to
11:11:07our postman. So I'm just going to copy
11:11:08this and let's run it. Right. So we have
11:11:114,000/ API/ o/ we have register correct.
11:11:16Now let's go to our body and we have to
11:11:18select raw and we have JSON. So now
11:11:21let's send uh email.
11:11:24So I'll send this email [email protected]
11:11:28and then here also uh what we are going
11:11:30to do right maybe let's only keep email
11:11:34for now and let's send this.
11:11:37Okay we are getting route not found. Oh,
11:11:40we have to do post I bet. So do send.
11:11:42You'll see that we are getting email and
11:11:44uh password are required. Let's see what
11:11:45we getting here.
11:11:48So we're getting app email and password
11:11:49and required.
11:11:52We getting cannot set headers after they
11:11:54say. Okay, these means we are sending
11:11:56the response to time sending back. So
11:11:58something we are doing wrong here. Uh so
11:12:01let's go to our uh service. So we are
11:12:03doing email and password require app
11:12:05error.
11:12:09Okay. So go to error handler. We'll see
11:12:11what we doing. How we have to return
11:12:13here. That is the reason. So when we
11:12:15doing response uh sending this response,
11:12:17right? So you have to return from this.
11:12:19So now let's save this. So now let's try
11:12:22once again. I think that error should
11:12:23not come. So we send we'll see that you
11:12:26are not getting that right. So getting
11:12:27email and password are required. Comma.
11:12:29And here we are going to do password.
11:12:32And now what we going to do right? So
11:12:33for this one 2 3 4. Let's keep it like
11:12:36this. send this. You'll see that we're
11:12:37getting password at least six characters
11:12:39long. Fantastic. So now let's do 5 six
11:12:43and then I'm just going to do send. You
11:12:44can see the registration is successful
11:12:46and please login to continue. That means
11:12:48this user is now present in our DB.
11:12:51Okay. So that means this uh particular
11:12:54code is now ran this create user. Okay.
11:12:57So with this this part is completed. The
11:13:00only basic register flow. Now you might
11:13:02be thinking one very important point.
11:13:04I'm not sure if you can uh actually
11:13:06check this particular thing that in our
11:13:08user table we also have what is that uh
11:13:11where is that user table man uh this one
11:13:14role so you have by default this is as
11:13:17user correct but how we are going to
11:13:19create admin then and you notice that we
11:13:22are not sending like this role equal to
11:13:24user actually you should not do like
11:13:25this and this is not a good good
11:13:27practice so the point is there are
11:13:29multiple ways we can create admin user
11:13:31okay so I'm just going to give you some
11:13:32very basic overview and some of The
11:13:34things are actually very important
11:13:35you'll see that in companies also they
11:13:36usually use first one is when you are
11:13:39going to create any admin user first of
11:13:41all you can directly update in your DB
11:13:43that is absolutely fine there is no risk
11:13:45though no wrong in this particular
11:13:47process also so let's say you are
11:13:49creating one particular SAS application
11:13:51and you are the owner and you want you
11:13:53to be admin right so it'll be admin so
11:13:55you can go to your DB you can directly
11:13:58uh update that particular role you can
11:14:00change your role from user to admin
11:14:02second And you can have a admin script
11:14:05just like we created a migration script.
11:14:07We can also have a admin script. Right?
11:14:09Third is like this is little more
11:14:11production level. So what companies are
11:14:12using they they use different tool.
11:14:14Okay. Now they have their internal tool
11:14:16also. Now in this internal tool they
11:14:18have some configuration management.
11:14:20Configuration management and there they
11:14:22can do right they can have some admin
11:14:24emails. Consider like this. And once
11:14:26they will change that admin email and
11:14:28update the configuration automatically
11:14:29in your DB these values will be also
11:14:31updated. So they have some mechanism. So
11:14:33there are multiple ways we can actually
11:14:35create admin user because I'm pretty
11:14:37much sure sir this question can come to
11:14:39your mind that how we are going to
11:14:40create a admin user then because most of
11:14:43the user whatever we're going to create
11:14:44by default it will be created as a
11:14:46normal user and that makes sense. So
11:14:48that is the reason I just wanted to send
11:14:49this point. So with this so our uh
11:14:52register flow is completed. So in the
11:14:54register flow we don't have to do
11:14:55anything just save the user and save the
11:14:58password. That's it. Okay. also uh this
11:15:00one also very important. Okay. So just
11:15:02add a return here. I think this part we
11:15:04have missed. So with this now let's move
11:15:05to the next one which will be our login
11:15:07flow. Okay. So now let's create our
11:15:09login flow and we are going to use exact
11:15:11same uh flow that what we have done. So
11:15:14let's close everything. We'll start with
11:15:15our o routes. Okay. So first let's
11:15:19create one more route here and this will
11:15:21be so I'm just going to drawouter.post
11:15:24and this will be path will be login. So
11:15:26it will be SL api/
11:15:28login. Here also we're going to do
11:15:30async. So do request response next and
11:15:36here let's take a try catch. So in the
11:15:40catch we'll get error and then we're
11:15:42going to call out next and pass the
11:15:44error. So in the try first of all what
11:15:46you have to do again when you're going
11:15:47to login user is going to type email and
11:15:49password only. So I'm not repeating the
11:15:51same thing it's same only. So do email
11:15:53password and you're going to get from
11:15:55request dot body. Okay.
11:15:59Now first of all what we have to do here
11:16:01right remember once user will login now
11:16:04this time we are only not only going to
11:16:07redirect the user to our application we
11:16:09also need to store something related to
11:16:11that particular information right and
11:16:13what that something that's something we
11:16:15called as access token. Now by the name
11:16:18only you can understand access means
11:16:19this token is going to give user access.
11:16:22Right? Without this particular token,
11:16:24you will not be able to understand
11:16:25whether this particular user is actually
11:16:27authenticated user or not. So that means
11:16:29this access token is the token that we
11:16:32are going to store in our local storage
11:16:34session storage or in our cookies. That
11:16:36is like front end side logic, right?
11:16:38Once we are going to send this but
11:16:39because this is a backend tutorial, you
11:16:41have to understand that as a backend
11:16:42developer, your task is to create access
11:16:45token or refresh token. Refresh token is
11:16:46a separate concept. But let's understand
11:16:48access token because this is very
11:16:50important. Also this token is going to
11:16:52have some lifetime. Lifetime means let's
11:16:53say you want to you are creating very
11:16:55sensitive application there you want
11:16:58your uh access token to be only lived
11:17:01till 15 minutes means after 15 minutes
11:17:03if user uh don't do any kind of activity
11:17:06you are not doing any kind of activity
11:17:08you are going to auto log out that
11:17:10particular user from the application or
11:17:11maybe let's say you are creating some
11:17:13e-commerce application in that case 15
11:17:15minutes is not fine so you can keep the
11:17:17access token as maybe let's say 7 days
11:17:19I'm just giving example or 1 day 24
11:17:21hours Okay. So at the end you have to
11:17:24understand this access token whatever we
11:17:26are going to create is going to hold
11:17:28that user information and based on this
11:17:30we are going to check if the user is a
11:17:32authenticated user or not. So first what
11:17:35we going to do right. So let's do one
11:17:36thing. So for now I'm just going to do
11:17:39XY Z. Okay. Later we'll change this one.
11:17:41You'll understand why I'm doing like
11:17:42this. And for now let's create a login
11:17:45user. So I'll do login user. And here
11:17:47I'm going to pass the email and the
11:17:49password. Okay. We are not doing
11:17:50anything. this login user will be our
11:17:54service logic. So we'll go here and
11:17:56let's create another here. So I'm just
11:17:57going to do not here we have to do
11:18:00export as sync function this will be
11:18:05login user. So here also I'm going to
11:18:07get email this will be string password
11:18:09this will be string and here what this
11:18:12is going to return so this is going to
11:18:14return promise but now what we going to
11:18:16return right we are going to return one
11:18:18access token here. So I'm just going to
11:18:20return a access token. Okay. And this
11:18:22access token will be string. So that
11:18:24means this access token we are going to
11:18:26receive here. So now if I just do import
11:18:28and let's see if I just do access token
11:18:30here. I'm going to get the access token.
11:18:31So for now I'm not returning. Let's keep
11:18:33it like this. Okay. I'm also going to
11:18:35remove the import. Let's uh keep it like
11:18:37this only for now. So first of all we
11:18:39are going to simply give a condition and
11:18:41also remember because we doing a custom
11:18:43validation right? If I get some more
11:18:45like if I have time like if this this
11:18:48video is not crossing like two maybe 16
11:18:51hours or 18 hours something like that
11:18:52then it will be tricky or else I'm going
11:18:54to give you some idea that how you can
11:18:56use zord and everything to implement
11:18:57this validation but you might be
11:18:59thinking why I'm not using zord
11:19:01absolutely zord is industry standard you
11:19:03can use other packages but again because
11:19:05I when I create this video right I have
11:19:07to think from a beginner point of view
11:19:09also let's see if a student is watching
11:19:11this video and then you they don't have
11:19:13any idea that how they can create a
11:19:15custom error class and directly jump in
11:19:17learning in zod that that doesn't make
11:19:19any sense you're getting so you have to
11:19:21go from level one to level five not
11:19:24directly to level five so first of all
11:19:26let's copy this and then we going to
11:19:28first keep it like this simple now what
11:19:30you have to do so again we have to do
11:19:32normalize email and then I'm simply
11:19:34going to do email dot to lowerase dot
11:19:38trim okay now what you have to do here
11:19:41now this is actually very important
11:19:43concept Now what will happen right when
11:19:45you are actually giving your email
11:19:48and also you're giving your password. So
11:19:51now this time you're not registering you
11:19:53actually doing a login activity. So we
11:19:55have to check if this email is present.
11:19:57So that is the first thing you also have
11:19:58to check if this password is present and
11:20:00also if this is not a valid password. If
11:20:03this is not a valid password so we are
11:20:05we will not allow user to login. So
11:20:08let's say during registration I've given
11:20:10here 1 2 3 4 5 6. But while login I'm
11:20:13giving 1 2 3 4 6 5 and this is wrong
11:20:18correct. So that means we need to
11:20:19validate the password also when we going
11:20:22to login. So that means here what I'm
11:20:24going to do first I'm going to check
11:20:25this user is present or not. So I'm just
11:20:27going to do a find user by email
11:20:33with password email with password. Okay.
11:20:37And here we're going to pass a normal
11:20:38HTML. this method again when we sorry
11:20:41where we are going to create this this
11:20:42we're going to create in our repository
11:20:44so we'll go to our repository first
11:20:46let's copy this we copy this and then
11:20:49I'm simply going to do export as sync
11:20:52function so this will find user email
11:20:55with password here we're going to get
11:20:57the email which will be string and here
11:20:59we are going to return a promise
11:21:02so here we have this DB user with
11:21:05password row remember we have created
11:21:07this in our types or null. So now you
11:21:10can simply take our result. So result
11:21:12will be ait pool dot query. So here
11:21:16we're going to pass DB user with
11:21:18password row and here we can simply
11:21:21write. So I'll do select
11:21:24ID select email uh select email also we
11:21:29need the role also role password has and
11:21:33also let's take the created at.
11:21:37Okay. So this we're going to get from so
11:21:39do from so we have our users where email
11:21:43will be this
11:21:46okay and then we're going to simply pass
11:21:48our email and then at the end we're
11:21:50going to return result dot rows of zero
11:21:54or else null so this is going to give me
11:21:58that particular information okay so now
11:22:00we can go back to our o service so we're
11:22:02going to check so first what you have to
11:22:04check right so here I'm just going to
11:22:05check if this user dot
11:22:08And this is where I'm going to have this
11:22:10password has. Oh, first I have to import
11:22:12that. So I'm not getting that right. We
11:22:14have to import this. So user dot
11:22:16password has if this is not present. So
11:22:19I'm just going to do no. So in that case
11:22:22I'm simply going to throw new app error.
11:22:25And we are going to give a 401. Okay.
11:22:28And I'm just going to do invalid email
11:22:31or password. Okay. That's it.
11:22:35Uh what else? Now we are going to check
11:22:37if this password is a valid password or
11:22:39not. So I'm just going to do con is
11:22:40password valid. So then we are going to
11:22:44use a and we're going to use this brypt.
11:22:48We have to use bcrypt. We are using it
11:22:52brypt dot we have compare. So how we
11:22:56going to compare? Now this is one of the
11:22:57most important concept. How we going to
11:22:59compare? So you're going to compare with
11:23:01this password. This
11:23:04password is the password that you are
11:23:05sending from the UI side. Okay, means
11:23:08this is the actual password user is
11:23:10going to type. But then this password
11:23:12you're going to compare with which one?
11:23:15So you're going to compare with the one
11:23:16that is stored in your DB. Okay. So this
11:23:19password has easily stored in your DB.
11:23:21Correct? So that means if this password
11:23:24and user dot password has both are same
11:23:27that means this user given correct
11:23:29password 1 2 3 4 5 6. But if this user
11:23:31given 1 2 3 4 6 5 so that means this
11:23:34password is wrong. Okay. So that means
11:23:36there will be no match you are getting.
11:23:38So if this is the case so now we can
11:23:40simply check that if this password valid
11:23:43is false. So is password valid is false.
11:23:45So in that case I'm just going to throw
11:23:49new app error and I'm simply going to do
11:23:52401 and I'll do invalid email or
11:23:56password. And you notice one thing we
11:23:58are simply not directly telling that
11:24:00whether your email is invalid or
11:24:02password is invalid. Let user guess
11:24:03because there is a possibility that
11:24:05let's say some hacker uh hackers are
11:24:07trying to access right. So they don't
11:24:09know that whether the email is invalid
11:24:11or password is invalid. So giving a
11:24:12general message here. So if this is not
11:24:16invalid so I'm going to throw error if
11:24:18this is invalid. So now we are going to
11:24:20do what? We're going to create a access
11:24:21token. Now this is one of the most
11:24:23important concept. Okay. So we'll do
11:24:25access token and then we are going to
11:24:27create a sign access token
11:24:31and then what we're going to pass we're
11:24:33going to pass some information but
11:24:34before that let's create one more
11:24:38file here and that we're going to create
11:24:40in our leave and I'm just going to do
11:24:41jwt.ds DS. Okay. So this is where we are
11:24:45going to create our token. Now what
11:24:46actually token will consist now this is
11:24:48what we have to understand. See your
11:24:50[snorts] token is going to have let's
11:24:51say you have a user A. Okay. This token
11:24:55is going to have a user ID.
11:24:58Why? This user ID will be unique. This
11:25:01token is going to have a email
11:25:03information of that user and this token
11:25:06also going to have the role of that
11:25:07user. Either this user is a normal user
11:25:10or this user is a admin user. Correct.
11:25:12Now when we are going to create the
11:25:14token and that particular token is going
11:25:16to hold all this information. So we will
11:25:18be able to understand right that this is
11:25:20which user from the user ID what is the
11:25:23user email from this email and what is
11:25:25the user role from this role. Correct.
11:25:27So that means first of all we have to
11:25:28create a type here. So I'm just going to
11:25:29do export type and I'm just going to do
11:25:32token payload. Okay. Or maybe I'm doing
11:25:35wrong. Let's go to our types and then
11:25:38we'll keep it here only. token payload
11:25:41and this is where I'm just going to use
11:25:43a user ID. This will be string. Uh this
11:25:46also is going to have a email which also
11:25:48will be string. This is also going to
11:25:50have a role which will be string. So
11:25:52save this. Now we'll go here and we're
11:25:54going to create our access token. So I'm
11:25:55just going to export function. I'll do
11:25:58sign access token and this is where I'm
11:26:00going to get my payload. Why you need
11:26:02payload? Because you need to get the
11:26:03user ID, email and password. Correct?
11:26:05And this is what you're going to do
11:26:06token payload and this is going to
11:26:09return a string. So now what we're going
11:26:11to do right we're going to create some
11:26:12options but before that we need a
11:26:15particular package. So which package we
11:26:17need? So now let's search here JSON.
11:26:20What is JSON web token
11:26:27right? So JSON web token is a security
11:26:30blah blah between a code structure. JSON
11:26:33is a single uh string split into dots
11:26:35headers payload that we are going to
11:26:37discuss. So first you can see that we
11:26:39have to install JSON web token and we
11:26:41have this user payload and then based on
11:26:43this you have to create a token here.
11:26:45Okay first what we're going to do right
11:26:47so we'll go here install this. So I'm
11:26:50just going to install this one here. So
11:26:52go to this I'm just going to do clear
11:26:55install
11:26:56and also install the types.
11:27:02Okay. Now what you have to do, right? So
11:27:04this is going to need your secret JWT
11:27:07secret. Okay. So here I'm going to copy
11:27:09this. You go to your env.
11:27:13And then we are going to add one more
11:27:14here. So I'll do JWT secret and this
11:27:17will be super secret JWT key. Okay. Now
11:27:22we can change this one. For now we're
11:27:24going to keep it like this. And this one
11:27:26first we have to add this. So we're
11:27:28going to add this in our env. So we'll
11:27:30go here and go to our env. And then I'm
11:27:33simply going to take JWT access
11:27:38secret. Okay. And this is where I'm just
11:27:40going to use this sorry check required
11:27:42variables and I'm going to pass this JWT
11:27:44secret. Okay. Then I'm also going to
11:27:47take very very important. I'm also going
11:27:48to add one more here that okay what will
11:27:51be the time that till what time this
11:27:53particular secret will be accessible. So
11:27:55I'm just going to do here. So let's do
11:27:57JWT access expires in and let's give
11:28:02this one as 15 minutes. Okay. So till 15
11:28:05minutes this will be this particular one
11:28:07will be available or maybe let's do this
11:28:08one 30 for now you can change this one.
11:28:11So now what I can do right I can go here
11:28:13and then add one more. So I'll do JWT
11:28:15access expires in. So this will be check
11:28:19this and then we are going to pass the
11:28:21JWT access expires in.
11:28:25Okay, this is done. So now we can create
11:28:27our options. So how we going to create
11:28:29options? So first of all, we need to
11:28:30import something from JWT package. So
11:28:33I'm just going to do import JWT,
11:28:38from JSON web token. And what we need?
11:28:41We need sign in options. It's called
11:28:42sign options. Okay. So now this will be
11:28:45my type. So I'm just going to do sign
11:28:47options. And here what I have to pass
11:28:49it, you have to pass a expired when this
11:28:51will be expired. So here I'm going to
11:28:52get my env dot you'll see that we have
11:28:55this JSON access expires in and here you
11:28:58have to go see this is going to give you
11:29:00error okay TypeScript error. So here
11:29:02you're going to give as and you're going
11:29:03to give sign in options and then you
11:29:05have to pass the expires in here. Okay.
11:29:07And then you are not going to get the
11:29:09error and then how you're going to
11:29:10create actual token. So to create actual
11:29:12token you're going to return JWT and
11:29:14this is going to give you the sign
11:29:16method here. What you have to pass very
11:29:18very important. This is where you're
11:29:19going to actually pass the payload and
11:29:21this payload is going to hold your user
11:29:24information. You're going to pass the
11:29:25payload. You also need to pass your JWT
11:29:28secret. So I'll do JWT secret. And then
11:29:31you're going to pass the options. So
11:29:33these options now is going to hold your
11:29:35expiry. This is going to hold your
11:29:37token. So based on this token and based
11:29:39on this user information, it's going to
11:29:41create a uh JWT token. Okay. So now
11:29:44let's save this. So we go to all service
11:29:47to see how much uh sound is it's coming
11:29:49right from outside. Can't do anything.
11:29:52How many times I'm going to pause and
11:29:54redo. It's very uh difficult. Okay. So
11:29:57now we're going to create sign in. So
11:29:59this is going to receive the token.
11:30:01Correct?
11:30:02Uh this one we're going to import first
11:30:04and this is going to receive payload. In
11:30:07this payload now we going to pass the
11:30:08user ID. See we getting now from where
11:30:10you're going to get the user ID. This
11:30:12user ids you're going to get from this
11:30:14user information because this
11:30:15information is going to give you this
11:30:18user information right here. Select all
11:30:20of these. So now you [snorts] can go
11:30:21here and then I can simply pass user.
11:30:25user is going to have your ID email user
11:30:29dot email and then role user dot role
11:30:34you notice we are not adding the
11:30:35password here okay and then at the end
11:30:38we're going to now return the access
11:30:39token that's it so that means in the end
11:30:42we are [clears throat] doing the login
11:30:43and we're returning the access token
11:30:45save this and now if you go here and
11:30:49import this and now you can get the
11:30:51access token directly here so do access
11:30:53token
11:30:57Okay, we are getting error man.
11:31:03Oh, value is not used. That's correct.
11:31:06So now what we can do right simply we
11:31:08are going to return. So do raise dot
11:31:10status. So I'll do 200 dot JSON.
11:31:15And here let's pass the success will be
11:31:19true. And here we're going to pass a
11:31:21data. And here I'm going to call this
11:31:23access token.
11:31:28Okay, still we getting error. Access
11:31:30token doesn't exist on promise access
11:31:32token. This how come
11:31:41I'm doing some silly mistake only. Oh, I
11:31:44have to take a man here. See that's
11:31:47what. So now this is done. So that means
11:31:50we going to get the access token and
11:31:51this flow is now completed. Okay. So now
11:31:54what will be the next step? Next we have
11:31:56to create our uh what is that called
11:31:57middleware. But before that let's do one
11:31:59thing. Let's check this login flow
11:32:01first. So I'm going to go here
11:32:06and let's do post and I'll do login
11:32:10and let's do here email.
11:32:14So I'll do sum at the rate one but I'll
11:32:17change this on this and send this email
11:32:20and password are required. So here I'm
11:32:22just going to take the password and I'll
11:32:24do I'll give correct uh password but
11:32:26I'll given wrong email. You can see here
11:32:28right? So the email is wrong. Send this
11:32:30invalid email or password. So now I'm
11:32:32going to give correct email but wrong
11:32:34password. Send this invalid email or
11:32:38password. I'm going to give correct one.
11:32:393 4 5 6. Okay. send this and you're
11:32:42going to get your success data and this
11:32:44is your access token. Okay, this token
11:32:47is going to is actually holding all your
11:32:49information. This is holding your user
11:32:50ID, user email and user role. Okay, so
11:32:53this will be the overall flow. Okay. So
11:32:55what you should do right instead of
11:32:56directly jumping to middleware try to
11:32:58understand that what we have done we
11:32:59getting the data from our UI we're going
11:33:01to services. Okay. We are then checking
11:33:05this one. This is very basic validation.
11:33:07That's okay. Then we checking the email
11:33:09and then we're checking if the email is
11:33:11pres sorry user is present. If user is
11:33:13not present throw error. If password is
11:33:15not not matching throw error. If this is
11:33:18not the case then we're going to create
11:33:20the token and we are going to returning
11:33:21the token here. Okay. So with this now
11:33:23let's move to the next one which will be
11:33:26now we're going to create our middleware
11:33:28and also how you're going to get your
11:33:29current user information. So let's do
11:33:31this one in the next part. All right. So
11:33:33now let's create our middleware. So we
11:33:35have to create two middleware. One will
11:33:36be our authentication middleware and
11:33:38second one will be your admin middleware
11:33:40and both are very important. Okay. So
11:33:41first let's do one thing. Let's go here
11:33:43and let's create the first one. I'm just
11:33:45going to do o dot middleware.ts
11:33:49ts and also we going to create admin dot
11:33:52middleware
11:33:54ts. So first in this o middleware what
11:33:58we have to do. So first you have to see
11:34:00that when we are going to send the token
11:34:02right let's say you have a UI correct.
11:34:05Now let's say you're doing a API request
11:34:07something like this. So how you usually
11:34:09send your token right? So you are going
11:34:11to send your token in your request
11:34:14headers. Now if you remember in the HTTP
11:34:17module we have discussed about the
11:34:18headers. So in these headers one of the
11:34:20headers property will be called
11:34:22authorization. Okay. And in this
11:34:24authorization we are going to send our
11:34:26token. But how we usually send our
11:34:27token? We send this particular token as
11:34:30a beer token. So it's like this. So you
11:34:32have beer B E A R E R and then there
11:34:37will be a space and then there will be
11:34:40your token. So it will be beer space
11:34:44token. Now this beer is going to hold
11:34:46your token. So it's like a it's beering
11:34:48your token. So it's like a taking your
11:34:50token and this token we are going to
11:34:51send from our UI side to our back end
11:34:54side and back end is going to validate
11:34:55this token and based on that we are
11:34:57going to understand whether this user is
11:34:58a normally user or admin user whether
11:35:01this user is authenticated user or non
11:35:03unauthenticated user all these things.
11:35:05So if you go here and you'll see that be
11:35:08error token. So let's see what is what
11:35:10it's telling right. So first you'll see
11:35:12that it's a security grant the B
11:35:15industry standard to handle your JSON
11:35:16web token or JWT right. So you have your
11:35:19authorization you have your BR and then
11:35:21your actual token and you see that there
11:35:22is a space. Now this space is important
11:35:24because what you're going to do right
11:35:26when we'll split it so we are going to
11:35:28split it with space. So left side will
11:35:31be beer right side will be your token.
11:35:33So how we are going to get the token. So
11:35:35once you're going to split and take the
11:35:37right side of it, we will be getting our
11:35:38actual token. Okay. So this is how we
11:35:41going to send. So authorization BL and
11:35:43this is your token. So first what we're
11:35:45going to do, right? So I'm just going to
11:35:46do export function and I'll do
11:35:48authentication or authenticate. I think
11:35:50let's keep authenticate. Here we're
11:35:52going to get our request. Now this
11:35:54request will be
11:35:56so I'm just going to do import from
11:35:59express. So here we're going to get
11:36:01request. We're going to get response and
11:36:03we are also going to get
11:36:06next function. So request will be our
11:36:09request. Then we're going to get our
11:36:11response which will be our response and
11:36:13then we're going to have our next very
11:36:15very important which will be our next
11:36:17function. And here we're going to have a
11:36:19void. So first we are going to get our
11:36:21header. So I'm just going to do all
11:36:23header and this will be your request dot
11:36:26headers and then you're going to have
11:36:28your authentication. So you request
11:36:30header dot authentication. So you can
11:36:32see that right. So not authentication
11:36:34authorization request do header dot
11:36:36authorization. This is what actually
11:36:38it's telling here. Okay. Now what I'm
11:36:40going to do? So I'm simply going to do
11:36:42if not equals this o header dot starts
11:36:46with if this is not started with B
11:36:48error. So that means there is a wrong
11:36:50because it will always start with B
11:36:52error. So you can see that. So it's
11:36:53simply checking the if this token is not
11:36:55started with B error that means you're
11:36:56sending a wrong format from your UI side
11:36:59and also this will be space right so B
11:37:01error space so in that case what you're
11:37:03going to do you're going to call next
11:37:04middleware then you're going to pass a
11:37:06new app error and then you're going to
11:37:09pass a 401 so whenever there is a
11:37:11authentication related thing you're
11:37:13going to send a 401 and this will be
11:37:15access token is required
11:37:19so this is the first thing and then
11:37:20you're going to return then we're going
11:37:23to get our actual token. Okay. So, how
11:37:25we going to get our actual token? So,
11:37:26we're going to do token and this will be
11:37:29so we're going to get o header and now
11:37:30we're going to do I already mentioned
11:37:32we're going to split. So, we are going
11:37:34to split with what space and then we're
11:37:36going to take the right side right. So,
11:37:38split means zeroth and this is first
11:37:40one. So, we're going to do split and
11:37:42then we are going to do with space and
11:37:44then I'm going to take the first one.
11:37:46So, this is going to give me my actual
11:37:47token the right side of it. And now what
11:37:50we have to do now this is actually very
11:37:52important. Okay, now this is extremely
11:37:54important. I'm going to show you one
11:37:55very interesting thing. You'll see that
11:37:56if I just do request dot user, right?
11:38:00And now you'll see that this user is not
11:38:02present. And this makes sense because
11:38:04this request which is a type of request,
11:38:07this is not holding any user
11:38:09information. So that means we need to
11:38:11some inform express that okay in my
11:38:14request object, I also need to include
11:38:16this user object here. But how we going
11:38:19to do this? You're getting what I'm
11:38:20talking about means this will give you a
11:38:22typescript error because this user
11:38:23doesn't exist. So that means to inform
11:38:26express that okay you need to add or you
11:38:28need to append this user information in
11:38:30your request object. So how you going to
11:38:32do this? So go to types and then I'm
11:38:35just going to create express dot
11:38:38uh d.ts. So I'm going to create a global
11:38:41express and uh so first I'm going to
11:38:44declare uh express and here I'm simply
11:38:47going to append that one uh that
11:38:49particular
11:38:51sorry not express we are going to
11:38:52declare global
11:38:54and here inside this I'm going to take a
11:38:56name space which will be express
11:38:59and inside this we're going to take our
11:39:01interface and in our interface will be
11:39:03our interface of this request right so
11:39:06we have this request so simply we're
11:39:07telling express that you take your
11:39:09request object object and in this
11:39:11request object also append this user so
11:39:13that I can access this request do user.
11:39:15So now here we are going to submit a
11:39:17login this request interface I am going
11:39:20to add a user here and this will be
11:39:21optional and this user will be the token
11:39:23payload that we have created. This token
11:39:25payload is going to hold your user ID
11:39:27mail and role and you'll see that now
11:39:28you're not getting this error because
11:39:30this express is now holding. So express
11:39:32dot request do user equal to token
11:39:34payload you're getting. So that means
11:39:36this user is now appended in your
11:39:37request object. And then you're going to
11:39:39just do export this. That's it. So now
11:39:43this request do user what this value
11:39:45will be. So this will be so this request
11:39:47do user will be nothing but here we are
11:39:49now going to verify our access token. So
11:39:51I'm just going to do verify access token
11:39:53and you're going to pass this token here
11:39:55because you need to verify it. You just
11:39:57can't uh use any random token and then
11:40:01you can give user uh access. So we'll go
11:40:04to our JWT and then I'm just simply
11:40:06going to do export function and I'll do
11:40:09verify access token. We're going to get
11:40:12the token which will be string and here
11:40:14we're going to get our token payload.
11:40:16And now to do this we're simply going to
11:40:18do a try catch.
11:40:21So here I'm simply going to throw a new
11:40:23app error 401 and I'll do invalid or
11:40:27expired
11:40:29access token.
11:40:31And in this try now I'm simply going to
11:40:33do return.
11:40:35So we do JWT dot I think it's called
11:40:39verify. And here you're going to pass
11:40:41the token. But how you're going to
11:40:42verify? So you have remember in the env
11:40:45you have this JWT access secret. And
11:40:47based on it it's going to verify. Okay.
11:40:50And here you're going to simply pass as
11:40:52so do token payload. And this is done.
11:40:54So now this method is going to verify
11:40:56your JWT token. And this is what we
11:40:59actually verifying here. Okay. And then
11:41:01what you have to do, can you guess what
11:41:02you have to do here? Extremely important
11:41:05concept. Extremely important. So you
11:41:07have to always call your next
11:41:08middleware. Remember I already explained
11:41:10this one. If you don't call this next
11:41:12middleware, it will always stuck in
11:41:14middle. Okay, it will never call your
11:41:16next handler or it will never call your
11:41:18next middleware. So that means now this
11:41:20particular authenticate is a middleware
11:41:23which is going to check every request
11:41:26whenever you're going to use this
11:41:27middleware that whether the user is a
11:41:29authenticated user or not. Now to check
11:41:32the admin uh middleware how we are going
11:41:34to do this one. So first of all let's do
11:41:36one thing. Go here. I'm going to just
11:41:39copy this paste it here. So I'm simply
11:41:41going to do export function
11:41:44require
11:41:45admin.
11:41:47So I'm going to take request which will
11:41:49be request response which will be
11:41:52response
11:41:53next which will be next function
11:41:57and this will void. So simply I'm just
11:41:59going to check if this request do user
11:42:02I'm going to have user dot role. If this
11:42:05is not admin right if this user is not
11:42:08admin user so that means we're simply
11:42:09going to return next and this will be
11:42:12new app error and I'm going to return
11:42:14403 and I'm simply do that admin access
11:42:18required
11:42:20you don't have do not have uh admin
11:42:24access it seems something like this and
11:42:28then I'm simply going to return this and
11:42:31then what you have to do here again you
11:42:33have to call the next Okay. Always you
11:42:35have to call the next or else it will be
11:42:37stuck. Now I think this is done. So what
11:42:40will be the next? Next will be now let's
11:42:42do one thing. Let's go to our o routes
11:42:45and then I'm going to create one more
11:42:47route here. So what I need to do right I
11:42:49wanted to get my current user
11:42:52information. How you going to get
11:42:54current user information? Until unless
11:42:55you log in you don't have the token and
11:42:57from the token you'll be able to get the
11:42:59user information. So I'm simply going to
11:43:00do O router dot get
11:43:04and then I'm simply going to do me.
11:43:06Okay. And here for now I'm just going to
11:43:08do request response. Now this is not
11:43:10correct. It's not going to work but I
11:43:12wanted to show you that only. So ludase
11:43:14dot status and I'm simply going to pass
11:43:16200 dot JSON and here what I'm going to
11:43:19do right I'm simply going to do success
11:43:23will be true and here I'm going to pass
11:43:25a data and here I'm going to do user and
11:43:28this will be request and you're going to
11:43:29have this user correct save this and
11:43:32you'll see that this is not going to
11:43:33work and this is where you're going to
11:43:35understand one very important concept
11:43:36and that is how you can protect your
11:43:39routes
11:43:41save this so now I think We don't have
11:43:43any error. So let's go here. Uh copy
11:43:46this
11:43:48get and this will be / API/og/me
11:43:51and I'm going to just do send here.
11:43:54You're not getting any error. Sorry not
11:43:55getting any error but you're not getting
11:43:57any data. Why? First of all until unless
11:44:00you have the token. So here we don't
11:44:02know right if the user is logged in user
11:44:04or not. So how you're going to get user
11:44:05information? So that means what you have
11:44:07to do right in your authorization you
11:44:09have to actually pass your token. So
11:44:11let's say I'm going to pass a beer token
11:44:12here. I have to pass the token and then
11:44:14I also need to protect this particular
11:44:16router. How I'm going to protect? So
11:44:18this is where I need to use middleware.
11:44:20So middleware here is going to protect.
11:44:22So it's going to check if the user is
11:44:24authenticated user or not. So now to
11:44:26check this what you have to do in middle
11:44:28you just have to call that authenticate
11:44:30middleware. That's it. Now this is now
11:44:32is going to work as a barrier. So that
11:44:34means when it's going to do here it's
11:44:36going to check this middleware. If this
11:44:38is passed then it's going to run this.
11:44:40If this is fail so it's going to return
11:44:42error. For example, if you go here right
11:44:44and let's say first of all save this and
11:44:48now let's say if I run that particular
11:44:50from the postman you'll see that you're
11:44:52not going to get this response. What
11:44:54you'll get right you'll get B token is
11:44:56needed or access token is needed. Now
11:44:58see what will happen if I go here and
11:45:01send this see access token is required.
11:45:03So that means now this particular route
11:45:06is protected. Okay, protected by whom?
11:45:08Protected by this middleware. So if I go
11:45:10to middleware, it's checking okay, you
11:45:12don't have any beer token. So it's going
11:45:15to return this. If it will have beer
11:45:17token, then it's going to verify the
11:45:18token and then you're going to get your
11:45:20user information. I hope this is clear.
11:45:22So now what I'll do right, I'll go here
11:45:24login. I'm going to send this. I'm going
11:45:26to get the token. Copy this token.
11:45:29Go to this. Go to uh headers. And then
11:45:32I'm going to add one header. Okay. So
11:45:34let's add here authorization. And here
11:45:36I'm just going to do beer, right? So be
11:45:39error and then paste this. And then if I
11:45:41send this, that's it. So now you're
11:45:43getting your user, user ID, email, role,
11:45:46and the rest of the expiry blah blah.
11:45:49But this is the important. So you're
11:45:50getting user, you're getting what I'm
11:45:52talking about. So this is how you're
11:45:53going to implement the middleware. Now
11:45:55this token is actually hold this
11:45:58information here. Why? Because when
11:46:00you're doing verifying, right, is
11:46:01actually doing the verification here.
11:46:03Correct? And based on it, it's going to
11:46:05return also another very important
11:46:07concept. Uh where is that? Let's go to
11:46:10that
11:46:11o routes not routes service.
11:46:17Uh see this is where we are actually not
11:46:20this one uh
11:46:28uh this part only I'm talking about. So
11:46:29request dot user equal to verify access
11:46:32token right and here what we doing we're
11:46:34returning this return verify this is
11:46:36what I'm talking about. So actually what
11:46:37we doing first we are verifying the
11:46:39token if that is correct then only we
11:46:41are doing what we are attaching that
11:46:43user information in our request object.
11:46:45So this one in our request object. So
11:46:47that is the reason you're getting this
11:46:48information. The moment you will just
11:46:50change this token. Let's say if I do uh
11:46:52maybe let's do P to A. Okay. And send
11:46:55this invalid or expired access token.
11:46:58See it will work right and then if you
11:47:01let's say copy this again from here
11:47:03let's say I'm going to copy this and
11:47:04then again replace here you'll see that
11:47:06you're going to get the result. So send
11:47:09this. That's it. So this is how you're
11:47:12going to protect. Okay. Now we haven't
11:47:14used this admin middleware because this
11:47:16we're going to use later but for now
11:47:18let's keep it like this with this. Now
11:47:19let's move to the next one. What will be
11:47:21the next part? Next part will be we are
11:47:22going to implement cloud right cloud
11:47:25means how we going to create update
11:47:26delete and all those things. And
11:47:27remember one thing here I wanted to
11:47:29mention before I know some of you are
11:47:31going to comment that okay in the O
11:47:32routes or O service we haven't
11:47:34implemented cookies where is log out and
11:47:36all of this we're not going to have all
11:47:38of this in this particular video and the
11:47:39reason is very simple if you want to
11:47:41learn all of this I already have a video
11:47:43for this or else wait for the next part
11:47:45in the next part we are going to have
11:47:46the rest of the topics that I already
11:47:48mentioned some of the things that I
11:47:50already mentioned in the previous core
11:47:51modules that we are going to have child
11:47:53process worker threads then some of the
11:47:55advanced topics uh here we are going to
11:47:58implement some advanced level of uh
11:48:00middle so not middleware means login
11:48:03flow email verification all all those
11:48:05things it's not possible to include each
11:48:07and everything here so I wanted to
11:48:08mention but for a beginner or even to
11:48:10complete a project this is more than
11:48:12enough so first let's implement our CRUD
11:48:14we are going to understand RBSC means
11:48:16role access control we are going to
11:48:18implement our admin side logic and then
11:48:20we'll move to file upload because there
11:48:21are still so many things are left so
11:48:23with this now let's move on to the next
11:48:24one all right so now what I going to do
11:48:26right So we start implementing our CRUD.
11:48:28CRUD means create, read, update and
11:48:31delete. Okay. Now first of all, let's go
11:48:33to types and we will start with creating
11:48:35our task uh type. So task.ts.
11:48:39Let's do this one as export type. Uh
11:48:42let's do task. So for your task, you're
11:48:44going to have a ID. So this will be
11:48:46string. You're also going to have
11:48:49task title which also will be string.
11:48:52You're also going to have a status. Now
11:48:54this will be string. And also let's see
11:48:56what else we have. Title status user id
11:48:59created and updated at. Right? So we'll
11:49:01copy this. So here we are going to have
11:49:03user id. This also will be string
11:49:06created at. This will be date. And then
11:49:09we are also going to have the updated at
11:49:12which also will be date. So this will be
11:49:14our type. So now first of all let's
11:49:16close everything. So let's see how many
11:49:19files first of all we need because we
11:49:21need to first check the flow and
11:49:24everything. So first of all as a user
11:49:26the first requirement will be this user
11:49:28has to be logged in user. So that means
11:49:31if you haven't logged in you will not be
11:49:33able to create any task. So that that is
11:49:35the first requirement. Then user will be
11:49:37able to create task. So this will be
11:49:40first requirement. User can only see the
11:49:44task created by that user only. I think
11:49:46that part we have already covered
11:49:48previously. User can update their task
11:49:50and user can delete their task. So four
11:49:53uh routes. Okay, from admin side what
11:49:57are you going to do? Right, admin will
11:49:58be able to see all the task created by
11:50:01all the users. So that means let's say I
11:50:02have two users. First user created 10
11:50:05task, second user created five task. So
11:50:07admin will be able to see all these 15
11:50:09task together. Okay. And second admin
11:50:12only will be able to update task status.
11:50:16So admin can update task uh status. Uh
11:50:19user can update uh their task title
11:50:22something like this. So first of all
11:50:23what we going to do right we need to see
11:50:25how many repository file we need. So
11:50:26first let's start with uh repository. So
11:50:29here I'm just going to create uh maybe
11:50:31let's do this one as either we can
11:50:34create only let's do user dot task dot
11:50:38repository.
11:50:42And then I'm also going to create one
11:50:43more. So this will be admin.task
11:50:46repository.ts.
11:50:48So one for user one for admin. Correct.
11:50:52Then we are also going to need our task
11:50:54services. So we'll go to our services.
11:50:56I'm going to create user dot task dots
11:51:00service.ts.
11:51:02Then I'll do admin.task dots service dot
11:51:06ts. Then we need our routes. Correct. So
11:51:10in the routes we are going to have two
11:51:11routes only. Uh the first one will be
11:51:13same. So we do user.task dot routes. DS
11:51:18and I'll do admin.task.outs.
11:51:21is. So then first of all let's start
11:51:24with again from our routes file. So
11:51:26let's close everything else go to index
11:51:29and let's create our first uh route
11:51:31which will be our task route for user.
11:51:34So here the first of all let's import
11:51:36okay then we are going to do so first
11:51:38import something from
11:51:40uh express
11:51:42and here we are going to first take I'll
11:51:45do export const and this will be our
11:51:48user task router. Okay. And this will be
11:51:51our router. Now first what we have to
11:51:53see right that all the task whatever
11:51:56operation that user is going to do so
11:51:59that user has to be logged in user. So
11:52:01that means whatever routes we are going
11:52:02to have in this particular file all
11:52:04routes has to be protected by our
11:52:06authenticated middleware. Authenticate
11:52:08middleware you're getting. So this one
11:52:10[snorts] we are going to understand uh
11:52:11in a minute. First let's do one thing.
11:52:12So I'm just going to do here uh let's go
11:52:15here. Right. So we'll go to our index.ts
11:52:17and here what are you going to do? So
11:52:19first of all you have to use this one.
11:52:20So I'll do app router
11:52:23sorry API router dot use and here let's
11:52:26give this one as uh let's do tasks and
11:52:30here I'm just going to do user task
11:52:32router. So that is the first thing. Now
11:52:34I'll go here. First of all we going to
11:52:36create our first route which will be how
11:52:38we are going to create one particular
11:52:40task. So I'm just going to do task user
11:52:43task router dot post. Let's give this
11:52:47one slash. So this will be our home
11:52:49route and here we're going to get a
11:52:51sync. So do request response and next
11:52:56and here so let's take our try catch.
11:53:01So you error
11:53:03and then we are going to call the next
11:53:05without error. So that is fine. But here
11:53:08what we are going to do right so first
11:53:09I'm just going to do con task and I'm
11:53:12just going to have it. So now we are
11:53:14going to create our service. So we'll go
11:53:15to our user service and here we're going
11:53:17to have our first service which will be
11:53:19create user task and what we are going
11:53:23to pass here. So first of all we're
11:53:24going to pass two things. Now you need
11:53:26to understand a couple of things here.
11:53:27Okay as I already mentioned that this
11:53:29router this route has to be protected.
11:53:31So here there are two ways you can do
11:53:34this. Now this is one of the most
11:53:35important concept you have to
11:53:36understand. First of all let's
11:53:37understand you have two routes here. One
11:53:40route has to be protected and other
11:53:41routes not. So in that case what you can
11:53:43do right you can use this authenticate
11:53:45middleware that we have on the route
11:53:47level only why because you can't use
11:53:50this one on the page level sorry on the
11:53:51file level because let's say you have
11:53:53one more here
11:53:55right you have one more and this
11:53:57particular route don't need this
11:53:58authenticate so in that case what you
11:54:00can do you can use this one individually
11:54:01you're getting but let's say now you
11:54:03have one more route and this route also
11:54:05need authenticate middleware so in that
11:54:07case instead of doing this one two times
11:54:09so one time here again one time here we
11:54:12can do something like this. We can use
11:54:13this one on the file level. Okay. So
11:54:16what I mean by this now if I go here and
11:54:18I'm simply going to tell okay use a task
11:54:20router dot use this authenticate. So
11:54:23simply we are telling that whatever
11:54:25routes I'm going to have in this
11:54:26particular file it can be two routes 10
11:54:28routes 20 routes all the routes will be
11:54:31now protected by the middleware. So now
11:54:34what you have to do right you have to
11:54:35use this one on the page level top top
11:54:37file. So not top file on the file on the
11:54:39top on the top you have to use. So
11:54:42whatever you are going to use after this
11:54:44all these routes so for example this
11:54:45route this route and you have let's say
11:54:4750 more routes all will be protected by
11:54:50authenticate authenticate middleware.
11:54:52Okay so that means all these routes are
11:54:54now protected. So all the routes below
11:54:58are now protected as simple as that. So
11:55:01this is how you can you can use or you
11:55:03can protect routes. As I already
11:55:05mentioned, I'm going to repeat once
11:55:06again. Let's say the requirement is you
11:55:08have to protect this one. You don't have
11:55:10to protect then you can't use this one
11:55:12because this will apply for all the
11:55:13routes. So in that case, you have to use
11:55:14this one on the route level. Something
11:55:16like this. So for this one, you need
11:55:18this for this you don't and then you
11:55:19have to remove this one. Okay. So for
11:55:21now because we need this particular
11:55:23authenticate middleware for all the
11:55:25routes, we are not going to use this one
11:55:27on the route level. Okay. So now let's
11:55:29remove this. So first of all, we are
11:55:31going to create our user task. Correct.
11:55:33So now we'll go to our service file and
11:55:35let's create our first service. So here
11:55:37I'm just going to do export async
11:55:40function and this will be create user
11:55:42task. What we need right? So first of
11:55:44all we need to know that which user
11:55:46actually creating this particular task
11:55:47and that is the reason we have this uh
11:55:50user ID right. So we have this user ID.
11:55:52So that means this one needs to have the
11:55:54user ID correct. So we are going to need
11:55:56our user ID. So user ID will be string
11:55:58and also we need the title. So title and
11:56:01this will be unknown. Now here what's
11:56:04this is going to return? So this is
11:56:05going to return promise and it's going
11:56:07to return task type that we have created
11:56:09in our task uh in the types file. Okay,
11:56:11remember we have created this one. So
11:56:13now what we going to do right? So first
11:56:14of all let's do validation. So first
11:56:17we're going to do con
11:56:19and let's do valid title. We are only
11:56:23checking the title here and this will be
11:56:25let's create one function. So I'm just
11:56:27going to do function and I'll do
11:56:28validate or valid title. Now let's do
11:56:31validate title and this is going to uh
11:56:34receive your title. This will be unknown
11:56:37and here you're going to use string. Now
11:56:39as I already mentioned we are actually
11:56:41going to use zord only but here you also
11:56:44need to know how you can implement all
11:56:45of this manually. So first I'm going to
11:56:48use this validate title. We are going to
11:56:50pass this user ID right not user ID
11:56:52title. So here what I'm going to do
11:56:54simply I'm going to check that if this
11:56:56type of title
11:56:59if this is not equal to equal to string
11:57:03or if this is false so that means if
11:57:06title dot trim
11:57:08in that case we are going to throw new
11:57:11app error and we're going to tell that
11:57:13okay this is 400 and I'm simply going to
11:57:15do title is required okay and now I'm
11:57:20simply going to do con trimmed title
11:57:23And this will be title dot trim.
11:57:27And then what you can do right that you
11:57:28can also give some condition. For
11:57:29example, let's say I wanted to check if
11:57:31this trimmed title.length
11:57:34if this is greater than maybe let's give
11:57:36a max title length of let's say 150 or
11:57:39100 something like this. So in that case
11:57:40also we can throw one more error. So
11:57:42I'll do throw new app error and I'm
11:57:44simply going to do 400. And I'll do
11:57:47title must be 100
11:57:50characters or less. Right? Now this also
11:57:54you can put this one in a constant file.
11:57:56Remember I told you to keep this one as
11:57:57a homework. So that you can do and then
11:57:59we are going to return the streamed
11:58:01title. Okay? So now this is going to
11:58:03validate title. Now what we're going to
11:58:05do right we are simply going to return
11:58:07and we are actually going to now
11:58:09interact with our DB. Now when I'm
11:58:10talking about interact with our DB so
11:58:13that means we need to at the end save
11:58:15this particular type support task in our
11:58:17DB correct so now we have to go to our
11:58:20repository file so we'll go to user.task
11:58:23task dot repository and we'll create our
11:58:25first function. So I'll do export async
11:58:29function and I'll do create task and
11:58:32here we are going to do user ID. We need
11:58:34the user id that which user is actually
11:58:36creating. So this will be string we also
11:58:38need the title of that task and this
11:58:40also will be string and here what will
11:58:43be the return type return type will be
11:58:44promise of this task.
11:58:47So now we are going to use this here. So
11:58:49this will be our return and you can do
11:58:51create task and what this is going to
11:58:53receive first of all let's import this
11:58:55and this is going to receive your user
11:58:57ID and title. So I'm just going to pass
11:58:59the user ID and I'm going to pass a
11:59:01valid title. Okay. So save this. So now
11:59:04what we have to do here? So simply going
11:59:06to create our SQL uh we have to write
11:59:09our query. So cool dot query and here
11:59:13you can do this one as task only. If you
11:59:16want you can also do like this. So you
11:59:18can do a type and let's do task row and
11:59:20this will be equal to this task and you
11:59:22can pass this also. Remember I told you
11:59:23that the DV for format and the actual
11:59:26format that you want to to return that
11:59:28that can be different but in this case
11:59:29it's same. So I'm just simply taking
11:59:31this only and here now I'm just going to
11:59:33write so what we have to write so we are
11:59:36going to insert. So I'm just going to do
11:59:38insert into and let's check our uh so
11:59:42this will be support task. This is where
11:59:44we are inserting this our table. What
11:59:46are you going to insert? You're going to
11:59:47insert title and also you're going to
11:59:49insert user ID. Correct? Then I'm just
11:59:52going to do values. So values will be
11:59:54one and two. And then I wanted to do a
11:59:58returning.
12:00:00So I'll return ID. I wanted to return
12:00:02the title. I wanted to return the
12:00:03status. Why we are not taking the
12:00:05status? Because by default status will
12:00:07be open. Okay. So you take status. Then
12:00:10I wanted to return the user ID.
12:00:13Then I want to uh return the create edit
12:00:15and update.
12:00:20That's it. And then uh what I have to
12:00:23do? So here after this I'm going to pass
12:00:26the title
12:00:29and the user ID.
12:00:31So I think this is done. And at the end
12:00:33we're going to return result dot rows of
12:00:37zero.
12:00:38So save this. So I think this is done.
12:00:41So now if we go here so what you have to
12:00:44use we have to use this create task user
12:00:46task here. So I'm going to import from
12:00:47our service and this is going to receive
12:00:50the user ID and the title. Now from
12:00:52where you're going to pass this user ID.
12:00:54Now this is where you have to understand
12:00:55from this request remember we have this
12:00:57request and this request is going to
12:00:59have your user information and this is
12:01:01going to give you the user ID. Now this
12:01:04we are going to actually get remember
12:01:05when we have validated the token right
12:01:08that time we are attaching this user
12:01:09information in our request object. So
12:01:11from where we'll be able to get this
12:01:12user id and then this will be request
12:01:14dot body dot title
12:01:18and now what you can do you can simply
12:01:20pass a dot status of 201
12:01:23JSON and here I'm just going to do
12:01:25success
12:01:27will be true and let's pass a data. So
12:01:30data will be this task that we have
12:01:32created. Save this. Now let's run it
12:01:35once again. See that this is running. So
12:01:38now first of all let's go here. Okay. So
12:01:39I'm just going to copy this.
12:01:42So I'll do post and I'll paste it. So
12:01:45this will be app API/ what is the route
12:01:48name that we are using. So let's check
12:01:51routes routes index. So we'll do / task.
12:01:55So / API/ task. Why? Because if you go
12:01:59to user task we are using only slash
12:02:01right so this will be / task and this
12:02:03will be post request we go to body json
12:02:05and let's I'm going to pass the title
12:02:08right so we have the title
12:02:12and this will be first
12:02:15support task correct let's try to send
12:02:18this you can see access token is
12:02:20required now from where you are actually
12:02:22getting you have to understand all this
12:02:24see because of this line you are getting
12:02:25this this authenticate is now is going
12:02:28to protect all the routes. So if you go
12:02:29to this authenticate, you'll see that
12:02:31it's simply checking whether you have
12:02:32the access token or not. So this is
12:02:34going to block the request. Correct? So
12:02:36now what you have to do right, you have
12:02:37to go to our login. Let's send this.
12:02:39We're going to get the token. So copy
12:02:41this token.
12:02:45Let's copy this one from here. And now
12:02:48if I go to authorization or let's go to
12:02:50headers, add one more. So I'm just going
12:02:52to add authorization and let's add a
12:02:54beer right space. So now let's try to
12:02:58send and that's it. So now you have your
12:03:01ID title is created status is open by
12:03:03default. This is your user ID. The user
12:03:05ID that created now you see this user ID
12:03:08and if you go to this user ID that
12:03:10particular user ID both will be same.
12:03:11Right? So for example if you go check
12:03:13this one B 0 A and check this one B 0 A.
12:03:18So that means this user actually created
12:03:20this particular task. So we'll be able
12:03:22to actually track that which support
12:03:24task is created by which user you're
12:03:26getting this user ID and this particular
12:03:28user ID both are same. So this about the
12:03:32creating. So creating is actually
12:03:33simple. Now remember you might be
12:03:35thinking I I know that some of you will
12:03:36be thinking oh this is very simple. I'm
12:03:38just adding one particular title. It
12:03:41doesn't like that. What you can do you
12:03:43don't have to exactly do like this. Now
12:03:45I'm adding only title. What will be your
12:03:48homework? Instead of adding only title,
12:03:50you can add 10 more properties here. But
12:03:53at the end, you have to understand this
12:03:55one that the process will remain same.
12:03:57Doesn't matter how many properties you
12:03:58are going to have here. At the end, the
12:04:00process or the flow will remain same. If
12:04:03you understand this flow, you will be
12:04:05able to create any kind of project.
12:04:06Okay. So with this now, let's move to
12:04:08the next one which will be our uh what
12:04:10is that? Uh next will be get fetching
12:04:13all the um task. So for this one we are
12:04:16going to do user task router get. So
12:04:19this will be slash and I'll do async.
12:04:22Let me just copy this one from here.
12:04:26And then we are simply going to take a
12:04:28try catch
12:04:33and then we're going to simply pass the
12:04:35error. And here what are we going to
12:04:38get? We are simply going to get all our
12:04:39task right? So I'm just going to do con
12:04:41tasks and I'll do a and I'll do get user
12:04:46tasks. Okay. So now first of all when
12:04:50we're going to create this service so
12:04:51let's go to service and let's create
12:04:53this. So I'm just going to do
12:04:55export async function and I'm simply
12:04:59going to do get user tasks. What
12:05:03actually you need? Now here you have to
12:05:05understand all of this. when you are
12:05:07going to get the task you need to pass
12:05:09this user ID because let's say there are
12:05:11two user A and B A created five task B
12:05:13created 10 task and you only need the
12:05:16created the task that is created by A.
12:05:18So in that case you need to know this
12:05:19user ID then only you'll be able to get
12:05:21it correct. So that means this get user
12:05:23task now need the user ID. So you are
12:05:26going to get the user ID which will
12:05:27string what this is going to return it
12:05:29is going to return a promise of task and
12:05:31this will be array because user can
12:05:33create multiple task also and here now
12:05:36we are going to return what we're going
12:05:37to create one more repository function
12:05:40here right here because we need to get
12:05:41the task from our DB only correct. So
12:05:44I'm just going to do export as sync
12:05:46function and I'm just going to do fetch
12:05:48task by user ID by user ID. Okay. So you
12:05:53need the user id this will be string and
12:05:57here what you're going to do you're
12:05:58going to do promise and this will be so
12:06:01we are going to get task. So now what
12:06:04you're going to do that simply will do
12:06:06const result.
12:06:08So this will be a pull dot query. So
12:06:12we're going to
12:06:14uh so this will be task row and now
12:06:16we're going to write our query. So I'll
12:06:18do select.
12:06:20So I'll do select ID title user ID. No
12:06:25uh we have a status status user ID
12:06:30created at
12:06:32and updated at. So all these I need from
12:06:35where? From our table. The table name is
12:06:38support task. So we'll do support tasks
12:06:42correct. So from that this table where
12:06:45based on what we are checking based on
12:06:47user ID. So where this user ID
12:06:50will be equal to this right. And then
12:06:53I'm also going to do a order by. So
12:06:56let's do order by of created at
12:06:59let's do disk. Oh no this will be wrong.
12:07:02Create at and this will be disk. And
12:07:04here you're going to simply pass a user
12:07:06ID. That's it. And then what you going
12:07:08to do? You have to return result dot
12:07:10rows. Why? Because there can be multiple
12:07:13task also. So save this. So now what
12:07:16you're going to do, right? We'll go to
12:07:17our uh task service.
12:07:20So here we're going to call this fetch
12:07:21task by user ID
12:07:24and we're going to pass the user ID.
12:07:26This is done. So now we'll go to our
12:07:27routes and then we'll import this one
12:07:29from our service. And what this is going
12:07:31to receive? This is going to receive the
12:07:32user ID. So you do request dot user
12:07:37dot user id. That's it. And then you're
12:07:40going to simply return. So you do race
12:07:42dot status of 200 dot JSON. And here now
12:07:48we're going to return success will be
12:07:49true. And we're going to return the data
12:07:52which will be these tasks. And this is
12:07:55done. So now this particular route also
12:07:57will be protected. Okay. So let's see
12:08:00this one whether this is working or not.
12:08:02So let's go here and then I'm going to
12:08:04just copy this create one more and this
12:08:07will be get and now let's do first of
12:08:08all let's do one thing let's try to send
12:08:10access token is required correct so we
12:08:13go to our login let's create one token
12:08:16we're going to copy this we'll go here
12:08:19let's go to headers let's add
12:08:21authorization
12:08:24let's add ber
12:08:27paste this and now see what will happen
12:08:28if I send this so we're getting the task
12:08:31created
12:08:32Now you might be thinking how it is
12:08:34getting the user ID. Correct. Remember
12:08:36this is actually getting the user ID
12:08:37from your request object and this
12:08:39request object from where you are
12:08:40getting we are actually getting from
12:08:42this token because at the end you are
12:08:44validating the JWT token right. So if
12:08:46you go to post here and let's say if I
12:08:47try to add one more so let's do second.
12:08:51So it's created one and if you try to go
12:08:53and send this now you're getting two
12:08:55task right. So first support task and
12:08:57second support task. Fantastic. Right.
12:08:59So that means fetching all the
12:09:03what that fetching all the task is also
12:09:05working. So now what you're going to do
12:09:06right we'll create our third one which
12:09:08is how we going to fetch a single task
12:09:10because now what is happening right we
12:09:12are getting all the tasks. So we need to
12:09:13fetch one single task. Okay. So now
12:09:16let's go here and let's see how we are
12:09:17going to do that. So first of all let's
12:09:19do one thing. I'm just going to do user
12:09:21task router dot get. Now what you have
12:09:24to do right remember here you are going
12:09:26to understand how you can create a
12:09:27dynamic API route. Dynamic API route we
12:09:31have to create like this. So we have to
12:09:32do task ID. Now what actually we're
12:09:34doing here? We're simply telling this is
12:09:35a dynamic parent. Why? Because when this
12:09:38particular user let's say created 10
12:09:40task each every t each and every task
12:09:42will have separate ID. So that means
12:09:44this task ID will be different. For
12:09:47example, your first task ID is one,
12:09:50second task ID is three, 2, 3, four,
12:09:52like this. Right? So when I wanted to
12:09:54get only fifth task, I need to replace
12:09:56this one with / five something like
12:09:58this. So that is the reason I'm sending
12:10:00a colon and then the param or query
12:10:03sorry parameter name here that will be
12:10:05dynamic right. So here now what I can do
12:10:07right I'll simply do async and this will
12:10:10be request response next.
12:10:15And now I'll just do try catch.
12:10:21So I'll do next call the error. And in
12:10:24this try so first of all I'm just going
12:10:25to do con task because we are fetching
12:10:28single task. So do ait. So do get user
12:10:32task by id.
12:10:37Okay. So what all we have to pass here.
12:10:39So first of all before this also let's
12:10:41do one thing. Let's return this. I'll do
12:10:42uh race dot status of 200 dot JSON. So
12:10:47here I'm just going to do success will
12:10:49be true and data I'm just going to pass
12:10:51this task here. But this is not yet
12:10:53completed. So first we have to go and
12:10:55fetch the single task. Correct. So go to
12:10:57service file and then we are going to
12:10:59create one more. So I'm just going to do
12:11:01export async function and I'm simply
12:11:04going to do get user task
12:11:07task
12:11:10by ID. Okay. Get user task or fetch user
12:11:14task. What we are using here? Get user
12:11:16task. I think it is fine. Get user task.
12:11:19That's fine. Get user task by ID. It's
12:11:21okay. Now here what are the things you
12:11:24need? Can you guess? First of all, you
12:11:26need to get the user ID. Second, you
12:11:29need to get the task ID. Because let's
12:11:31say if I try to get this particular
12:11:32task, you need this ID. Also, you need
12:11:36which user actually created this because
12:11:38it's actually better. Okay, you can
12:11:40actually face this use in this also. But
12:11:42you need the user ID here also. Okay, so
12:11:44that means you need two things. So first
12:11:45you need the task ID which will be
12:11:48string and also you need the user ID
12:11:51which also will be string. What this is
12:11:54going to return? So it's going to return
12:11:55a promise of the single task. So it will
12:11:57be task. And now what I'm can do right I
12:12:00can do const and this will be task and
12:12:02here I'm just going to do ait and I'll
12:12:04do find
12:12:06task by
12:12:09ID find task by ID and user ID. Okay.
12:12:14And here we're going to pass the task ID
12:12:16and we are also going to pass the user
12:12:17ID. So this one now we are going to
12:12:19create where again in our repository
12:12:21file because we at the end we need to f
12:12:23this one from our
12:12:25DB. So I'll do export as sync function.
12:12:28So do fetch task uh by ID and user id.
12:12:32So you need the task ID. This will be
12:12:34string. And also you need the user ID.
12:12:38This also will be string. So what this
12:12:41is going to return? This is going to
12:12:42return a promise of task
12:12:44or it can return null because it's
12:12:46possible that you are giving some random
12:12:48ID and that data is not present. Okay.
12:12:50So now I'm just going to do con result.
12:12:53So this will be have it pull dot query.
12:12:57So we're going to pass the task row and
12:13:00here we are going to now write our
12:13:02query. So we'll do
12:13:04select
12:13:07ID, title, status,
12:13:10user ID,
12:13:12created at and updated at. So all these
12:13:15thing we need from where? From our
12:13:18support task table. So do from support
12:13:20task
12:13:22and then we are going to do where id
12:13:25will be this. Okay, ID means your actual
12:13:30ID, the task ID. And you also need the
12:13:33user ID where user ID is equal to this.
12:13:36And then you're going to simply pass
12:13:37your ID means this will be your task ID.
12:13:39And then you're going to have your user
12:13:41ID. Very simple. And then you're simply
12:13:44going to return
12:13:46result dot rows of zero. But here it is
12:13:50possible. So you can also return null
12:13:51here. Okay, if that is not present.
12:13:53That's it you have to do here. So now we
12:13:55are going to import this in our service
12:13:57file and then we are going to give a
12:14:00very very important check because if
12:14:02this task is not present so in that case
12:14:04what I going to do right will throw new
12:14:06app error and I'm just going to do a 404
12:14:10and I'll do task not found. Okay and at
12:14:14the end we going to return the task.
12:14:17That's it. So this about our service.
12:14:20Now we go to here. So we need to first
12:14:22import this from our service and then
12:14:25what you need we need to was the task ID
12:14:26and the user ID. So task ID will be your
12:14:29this ID. But how you're going to get
12:14:31this ID now? So this ID you're going to
12:14:33get from request and request is going to
12:14:35give you these params and these params
12:14:36is going to have your task ID. See this
12:14:40is going to have your task ID and this
12:14:41this depend on what you're giving here.
12:14:43For example, if I do ID, see you're
12:14:45getting error. Why? Because now you have
12:14:46to give task ID you're getting. So
12:14:48that's the reason we just change this
12:14:50one to task ID. And here I'm simply
12:14:52going to do user ID. You already know.
12:14:54So do request dot user dot user ID. And
12:14:57this is done. So now let's save this and
12:15:00let's say if I just go here and let's
12:15:03create one more. So what I'll do right.
12:15:04So let's copy this
12:15:07first. Let's go here. So we're going to
12:15:09do this. And now what I have to do, we
12:15:11have to pass the dynamic value, right?
12:15:13So / task ID. So maybe let's take this
12:15:16task one first one. Okay. So this ID you
12:15:18wanted to take and I'll do / this. And
12:15:23now what I'm going to do right I'm going
12:15:24to send here and you can see that we are
12:15:25getting access token is required which
12:15:27is uh expected because we need to pass
12:15:29our token. So we go to our login
12:15:33get our token
12:15:36and let's go to headers add
12:15:40authorization and I'm simply going to
12:15:43add a beer
12:15:48and paste and now let's try to send and
12:15:52that's it. So you're getting success and
12:15:54you're getting this data. Okay. So now
12:15:56let's see go here and maybe let's I try
12:15:58to add this copy this and if I go here
12:16:01let's change this one to this send and
12:16:04you're getting second task and let's say
12:16:06if I just change this I uh ID to a
12:16:08different ID send this you're getting
12:16:10task not found that means you're getting
12:16:12404 and that is coming from your service
12:16:15from this line okay so this is completed
12:16:18so now next one will be update right so
12:16:20let's say how we are going to do update
12:16:22so I'm going to create one more and this
12:16:24time we're going to use not get not post
12:16:27we are going to use patch because we are
12:16:29only going to update a certain uh
12:16:31portion or certain property in our DB so
12:16:33you don't have to update all the
12:16:34properties right so in this case when
12:16:36you're going to patch something let's
12:16:38say uh if I go here let's say one task
12:16:41two task three task and in this
12:16:43particular task you wanted to update
12:16:45some property let's say you wanted to
12:16:46change the name from sum to John so in
12:16:49that case you need to also know the
12:16:51which ID you wanted to update right so
12:16:53that means these al will be a dynamic
12:16:55value. So in this case also what we
12:16:57going to do? We are actually going to
12:16:59tell that okay this ID we wanted to
12:17:01update right. So this task ID will be
12:17:03what again dynamic value you're getting
12:17:05and then we are going to take async.
12:17:08So we're going to get request response
12:17:11next
12:17:13and here we are going to do a try catch
12:17:17error and then we're going to do next
12:17:19and we're going to call out error. So
12:17:21first of all what we have to do. So
12:17:23first let's do a const and we're going
12:17:25to take task and I'll do a and I'll do
12:17:28update user task. Okay. So what are the
12:17:32things that you need here? So this is
12:17:33the first thing. See first of all you
12:17:35need to know which task you wanted to
12:17:36update. So that means you need the task
12:17:38ID. Second you need which user actually
12:17:41created that particular task. So that
12:17:43means you also need the user ID. And
12:17:45that makes sense. Correct? Let's say I
12:17:46wanted to update this task from second
12:17:50support task to second support task
12:17:52edited. So that means I need to change
12:17:54this title. Correct? So that means I
12:17:56need sorry I need this title. I need
12:17:59this user ID and also I need this title
12:18:02also. Why? Because consider you are
12:18:04having a UI and from this UI user is
12:18:07going to update right? So that means
12:18:09this title value you need the updated
12:18:11title value. Consider I wanted to change
12:18:14this uh second support task to sum
12:18:17something like this. So that means I
12:18:19need that updated value correct then
12:18:20only you'll be able to understand okay I
12:18:22need to update the title but what will
12:18:24be the value that you don't know so that
12:18:26you're going to get from your UI side
12:18:28right from your front end so that means
12:18:30in this one we need three things but
12:18:32before that let's do go to our service
12:18:34and let's first create this. So here
12:18:36what I'm going to do right I'm simply
12:18:37going to do export as sync function and
12:18:40here I'm just going to do update user
12:18:43task. So we need the task
12:18:46we need the task ID which will be
12:18:48string. We also need the user ID which
12:18:51will be string and also we need the
12:18:53title that will be also string. What
12:18:56this is going to return again it's going
12:18:57to return promise of the task.
12:19:00So first of all I want to do valid
12:19:02right? I wanted to do valid title and
12:19:04this will be our validate title and I'm
12:19:06going to pass the title and now what I'm
12:19:09going to do first I'm going to do con
12:19:11task and I'll do update task
12:19:15title and this one we are going to do
12:19:18where we are going to write in our
12:19:19repository because at the end you have
12:19:20to remember you have to interact with
12:19:22your DB only right so if you go here and
12:19:25let's create one more so I'm just going
12:19:26to do export async function and I'm
12:19:30simply going to do update task ask title
12:19:33this is also going to receive these
12:19:35three things I'm not going to write
12:19:36let's copy and paste and then here
12:19:42we are going to do promise and I'm
12:19:43simply going to do this will be either
12:19:45task or else this will be null again why
12:19:47because let's say you are updating one
12:19:48particular task that task is not even
12:19:50present so in that case this will return
12:19:52null correct so I'm simply going to do
12:19:55con result so I do ait pool dot query so
12:19:59we're going to pass the task row and
12:20:01then try to write the query by yourself
12:20:03because by this time I hope that you
12:20:05completed the postgress section and also
12:20:07you have written multiple uh query also
12:20:09so I think you should do all of this how
12:20:11you going to update so here you can't
12:20:13use select correct so you have to do
12:20:14update where you wanted to update we
12:20:16wanted to update our support task table
12:20:20right so now what we have to update so
12:20:23you have to update the title property so
12:20:25I'm going to do set which property title
12:20:28which will be equal to one and then I'm
12:20:31Just going to do updated at this will be
12:20:34equal to what now because the when
12:20:37you're updating that time you also you
12:20:39need right that time stamp now what
12:20:41you're going to do where now you're
12:20:42going to tell okay because your DB
12:20:44doesn't know right okay which item I
12:20:46need to update let's say you have 10
12:20:48task and you wanted to update the fifth
12:20:50one so you need to tell right okay where
12:20:52the ID will be this
12:20:54and user ID will be this so simply I'm
12:20:58telling that okay you wanted to update
12:21:00this particular First of all, you wanted
12:21:02to update support task table. You wanted
12:21:04to update the title property. You wanted
12:21:07to update the updated property. But how
12:21:08we are going to understand which title
12:21:10where the ID is this and user ID is this
12:21:13mean this means user ID means this task
12:21:16is created by that particular user. And
12:21:18this is the title ID where I wanted to
12:21:20update. And now what I'm going to do I'm
12:21:22going to do a returning and this will be
12:21:25ID title status user ID
12:21:30create or let's write it man copy this
12:21:32from here created and updated at these
12:21:34two things so here I need this that's it
12:21:37and then you're going to password so
12:21:39first of all what is our first one first
12:21:40variable so which is title so this will
12:21:43be your title then next is your ID so
12:21:46this will be your task ID don't make
12:21:47this mistake okay all of these and last
12:21:49one is your user ID and This will be
12:21:51your user ID. And then at the end you're
12:21:54going to return result dot rows of zero
12:21:58or else
12:22:02this will be null.
12:22:04So save this. I think this is done. So
12:22:06now we'll go to our service means task
12:22:10service. And now here what we're going
12:22:12to do. So first of all let's import this
12:22:14and we're going to pass the so we have
12:22:17task ID, user ID and title. So first I'm
12:22:19going to pass the task ID, user ID and
12:22:21the title. And then I'm going to give a
12:22:24check that if this task is not present
12:22:26or we have to pass a valid title, not
12:22:28this one. Task is not present. So I'm
12:22:30just going to throw new app error.
12:22:33So 404 and I'll do task not found. And
12:22:38also this is going to return null also.
12:22:40So in that case I'm simply going to
12:22:42return the task here.
12:22:45So save this. So now I'll go here and
12:22:47then you're going to copy sorry import
12:22:49this first and this update task is going
12:22:51to receive your task ID. So how you
12:22:52going to get the task ID? Task ID will
12:22:54be your request dot params dot task ID.
12:22:58Next you're going to pass the user ID.
12:23:00User ID will be request dot user dot
12:23:04user ID and then you're going to pass
12:23:06the title. Title will be from where
12:23:07you're going to get. So title you're
12:23:09going to get from request dot body dot
12:23:12title. That's it. Save this. And then at
12:23:15the end what we going to do? We're going
12:23:16to return race dot status of 200. So in
12:23:20this case also we're going to return 200
12:23:23dot JSON and we're going to do success
12:23:26will be true and data will be task
12:23:31this task. Save this. So now if we go
12:23:34here right so let's say maybe I wanted
12:23:36to update this task only. So I'm just
12:23:38going to copy this add one more paste it
12:23:42here. This will be patch and let's say
12:23:44try to okay first of all I'm just going
12:23:46to add one
12:23:48here I'm just going to update the title
12:23:51so title I have second support task
12:23:55correct so let's change this one to
12:23:57second support task title edited okay
12:24:03try to send first we're getting access
12:24:05token is needed so first let's log get
12:24:09the token
12:24:12And then I'll go to headers add a
12:24:15authorization
12:24:17and I'm going to do be error
12:24:20and then try to send and you can see
12:24:23that now you're getting second support
12:24:24task is edited. Okay. So that means this
12:24:27is working fine. Now try to fetch all
12:24:29the task. Okay. So I'll go here send
12:24:31this. So it's invalid. So okay let's
12:24:33change the token first
12:24:36paste here and then try to send and you
12:24:39can see that now you're getting second
12:24:40support task edited. So that mean this
12:24:42is working fine. If you go here right
12:24:44try to send this you're getting second
12:24:46support task edited. All right. So I
12:24:47think this is completed. So the last
12:24:49step the last one that is left and that
12:24:51will be delete. Okay. So with this crowd
12:24:54will be completed. So create update uh
12:24:56read and delete. So let's do the delete
12:24:58in the next part. Okay. So now let's
12:25:00implement our uh delete one right. So
12:25:02for delete what we'll do? We'll do use a
12:25:04task router and we going to use the
12:25:06delete method. Here also when you're
12:25:08going to delete so we are going to
12:25:09delete a certain support task correct so
12:25:12in this case also this will be dynamic
12:25:15uh so here uh task ID and then let's
12:25:18take a sync and let's copy this
12:25:26and here we are going to take a try
12:25:29catch
12:25:32so call next with error and here in the
12:25:35try so simply we're going to do private.
12:25:37So we'll do delete user task. So what
12:25:41are the things we need? So first of all
12:25:42let's create our service, right? So this
12:25:44will be simpler. So what I can do is
12:25:46I'll do export
12:25:49as sync function and this will be delete
12:25:53user task. So first of all you need the
12:25:55task ID
12:25:58and also you need the user ID. both you
12:26:00need and what this is going to return
12:26:03it's going to return a promise and it's
12:26:04going to return void nothing so here I'm
12:26:07simply going to do const deleted so do
12:26:10ait delete task so here let's go to our
12:26:16repository first
12:26:18and let's uh delete the task so first
12:26:20I'm just going to do export as sync
12:26:23function
12:26:25so do delete
12:26:28task so So you need the task ID which
12:26:31will be string and also you need the
12:26:34user ID. This also will be string and
12:26:38here so let's do a promise and because
12:26:40we deleting this one from our DB I'm
12:26:42going to return a boolean here. Okay. So
12:26:44we'll do con result. So this will have
12:26:47it pull dot query. So what are you going
12:26:51to do simply? So we're going to tell
12:26:54that you are going to delete something.
12:26:56So delete from where? So from your
12:27:00support task table uh here. Okay. So
12:27:03we'll do delete from support task where
12:27:07id equal to this and user id is equal to
12:27:13this. And then you're going to simply
12:27:16pass your task ID and user ID. That's
12:27:19it. What do you have to return? So
12:27:21you're going to return your result
12:27:24dot row count or else zero and this
12:27:29we're going to simply do this is greater
12:27:30than zero. So then it will be true.
12:27:33Okay. So that mean this particular row
12:27:34will be deleted. All right. So now let's
12:27:37import this. We're going to import
12:27:38delete task here. So I'll do delete task
12:27:42and we're going to pass the task ID and
12:27:44the user ID. Okay. So I'm simply going
12:27:46to check if not equal to deleted. So
12:27:48just throw one error here. So do new
12:27:50error. Sorry, app error 404.
12:27:55I'll do task not found.
12:27:58Sorry, this will be not deleted. Save
12:28:00this. So now we'll go to here and what
12:28:03we're going to do, right? So we can
12:28:04directly call this delete user task.
12:28:06This one, this particular service from
12:28:08our route. But we have to send a
12:28:10response back. So I'm simply going to do
12:28:11rest dot status 200. And let's do a
12:28:15JSON. And we are simply going to do
12:28:17success will be true.
12:28:21And let's pass a message that task
12:28:25deleted successfully
12:28:28from DB. Okay. So save this. So now I'll
12:28:32go here. Maybe let's do one thing. I'm
12:28:35going to copy this only. Create one
12:28:37more. Uh paste this one. Let's do this
12:28:41one. Delete. And we have this ID, right?
12:28:43This one. So let's copy the I think this
12:28:45only we are using here. That's fine. So
12:28:47let's try to send. So access token is
12:28:50needed which is correct. So let's get
12:28:53one token now. So I'm going to
12:28:56take this. We'll go here. Go to headers.
12:29:02Uh so let's do authorization. And here
12:29:04I'm going to do the error.
12:29:07And then let's see send task deleted
12:29:11successfully. Right. And if you try to
12:29:12send one more time, task not found.
12:29:14Fantastic. So let's go here and let's
12:29:16try to send. You're getting only one
12:29:18task means that is created. Sorry that
12:29:20is deleted. Okay. So this will be our
12:29:23CRUD. So create, read, update and
12:29:26delete. What you have to understand or
12:29:27what you have to practice right this
12:29:29page. Why this page is very important
12:29:31for this is where you are actually going
12:29:33to do and believe me uh one thing I'm
12:29:35going to mention that whatever project
12:29:37you are going to create any project any
12:29:39project I'm talking now there can be
12:29:41some exception that is fine. whatever
12:29:43project whatever complexity at the end
12:29:46you are going to do something create
12:29:48something you're going to do like
12:29:50reading or fetching updating or delete.
12:29:52So that is the reason this part is very
12:29:54important. What you can do right you go
12:29:56to support task instead of title and
12:29:58status try to add some three or four
12:30:00more properties and then try to
12:30:02implement the same thing again and
12:30:03again. Okay. So to do more practice. So
12:30:05with this now let's move on to the next
12:30:06one. So next will be our admin set
12:30:08feature. So admin set feature. So what
12:30:10admin will be able to do? So for now
12:30:12user can only fetch their own task.
12:30:15Correct. But admin as admin you will be
12:30:17able to fetch your uh fetch all the
12:30:19task. All right. So with this now let's
12:30:21move on to the next one. All right. So
12:30:23now we are going to create our admin
12:30:24side routes. Correct. So as I already
12:30:26mentioned that admin will be able to do
12:30:28what? We'll be able to fetch all the
12:30:30task. Second admin will be able to
12:30:32update the status. But before that you
12:30:33remember that we only have one
12:30:35particular user. Correct. So we need to
12:30:36create a admin user. So how we can do
12:30:38that? We can directly query our DB and
12:30:40then we can update one particular user
12:30:43role from normal user to admin user.
12:30:45Okay. So let's see how we are going to
12:30:46do that. So first of all what I'll do
12:30:48right? So let's increase this one and
12:30:51then okay we'll go here let's clear and
12:30:54then first of all we are going to run
12:30:56couple of commands. So we're going to
12:30:57run this docker execute and then this
12:31:00will be what? So this is our container
12:31:03name right. So you go to docker compose
12:31:05we'll see that we have container name
12:31:07and then you have your posgress db. So
12:31:10this is your posgress db right? So we
12:31:11are going to just copy this and then we
12:31:14are going to just run it. Okay. So now
12:31:18here we can directly query. So I I need
12:31:20the id, email and role from my user
12:31:22table normal query. Okay. So just paste
12:31:24it. So do paste enter and see that we
12:31:27have only one right. What I'm going to
12:31:29do? So first let's go to our uh user
12:31:32right. So register. So here I'm just
12:31:35going to create an admin user. So I'm
12:31:36just going to do john at thegmail.com.
12:31:38I'll keep the same password and I'm
12:31:39going to send registration successful.
12:31:42Correct. So now what I'll do right? So
12:31:44I'm just going to exit from this. So
12:31:45I'll do Q. So let's clear. Let's run
12:31:48once again. And then what I'm going to
12:31:50do, I'm just going to copy this and
12:31:53paste it here. Enter. And now you have
12:31:55two user. So what I'll do right, I'm
12:31:57going to change this [email protected]
12:31:59from normal user or let's say this user
12:32:02also. Let's do this only from normal
12:32:04user to admin user. So how we can do
12:32:06that? So update user, right? So we are
12:32:09updating the user table. Set role will
12:32:11be admin where email is what? Email is
12:32:14this email. So [email protected]
12:32:16makes sense. Now this we are going to
12:32:18just paste it. So now what I'll do right
12:32:21I'll copy this and then I'm just going
12:32:23to execute this enter and you can see
12:32:26that this is done. So now what we can do
12:32:28right if you check this you'll see that
12:32:29now this is a admin user correct and
12:32:31this is what actually we need. So now we
12:32:34have one super admin which is
12:32:35[email protected]
12:32:37correct? So this is what we are going to
12:32:39do first of all. Now let's do one thing.
12:32:41Let's go to our admin routes first. So
12:32:44we'll go to our admin routes. So we have
12:32:46routes routes. Routes we have admin
12:32:48routes. So okay. So here first let's
12:32:51start with creating. So how many routes
12:32:53we need? First we need mainly two
12:32:55routes. One where we are going to fetch
12:32:57all the task. Second we are going to
12:32:58update the status. But before that one
12:33:01very important thing you're going to
12:33:02understand now and that is so first
12:33:04let's import something from uh we do
12:33:08express and I'm simply going to do
12:33:10export con admin task router and this
12:33:16will be router and here first uh let's
12:33:20do one thing let's go to our index and
12:33:22I'm just going to do copy this and let's
12:33:25do /admin / task and here I'm just going
12:33:28to do admin task ask router. Okay, save
12:33:31this. So now first of all what we have
12:33:33to do here we have to protect the
12:33:35routes. Now this is important. Now this
12:33:37is where this particular page or these
12:33:40routes whatever we are going to create
12:33:42in this particular file only admin can
12:33:44access. So that means if you directly
12:33:46just do admin task router
12:33:49while I'm doing no let's do this one
12:33:51capital man. This is not correct. Let's
12:33:54keep capital and I'm going to import
12:33:56this and then I'm just going to do if I
12:33:59do admin.outer do use let's I'm just
12:34:02going to do authenticate. Now what will
12:34:04happen now this is actually normal user
12:34:06authentication right but we need to add
12:34:08one more layer that means first we have
12:34:11to check if this user is a normal user
12:34:14and if this user is a admin user second
12:34:17we also have to check if this user is a
12:34:19logged in user or not. So that means
12:34:21what I mean uh what I mean by this so
12:34:23let's say we have a user we have a admin
12:34:25correct for normal user we are simply
12:34:28checking if the user is logged in or not
12:34:30so if the user is logged in so this is
12:34:33fine but for the admin user we have to
12:34:35check two things first we have to check
12:34:36if the user is logged in plus we also
12:34:39have to check if the user role is admin
12:34:41user or not. So that is [snorts] two
12:34:43check we need to do. So that means this
12:34:45is only one check. So this is only going
12:34:47to check if the user is logged in. So
12:34:49how we are going to check if the user is
12:34:50a admin user or not? This is where we
12:34:53have this admin middleware. So this
12:34:55admin middleware is actually going to
12:34:57check if this user is admin user or not.
12:34:59So that means what we can do that we can
12:35:01use multiple middleware together. So to
12:35:03use multiple middleware together we have
12:35:05to give comma and we are going to use
12:35:07require admin. That's it. So that means
12:35:09we are simply telling that there are two
12:35:11level of check. First you check if the
12:35:13user is logged in user plus if the user
12:35:15is a admin user or not. both has to be
12:35:18satisfied. Then only we will allow user
12:35:21or we'll allow this particular code to
12:35:23go to the next middleware or go to the
12:35:24next route handler. So now what I can do
12:35:27right I'll do admin task router dot get.
12:35:30Now let's do slash and here I'll do
12:35:32async request
12:35:36response next.
12:35:39So I'll do try catch
12:35:43and we're going to call the next with
12:35:45error. So now first of all let's do a
12:35:49const and I'll do data and I'll do a get
12:35:53admin task.
12:35:57Okay. So first what we have to do here?
12:36:00So first of all let's do one thing.
12:36:02Let's go to our admin service. Right. So
12:36:05let's go to admin task service because
12:36:07this is where we are going to write our
12:36:09service logic. So first of all here we
12:36:11are going to uh do couple of changes.
12:36:13Okay. Before that we also let's do one
12:36:16thing right. So let's also implement uh
12:36:18some of the search and filter pattern so
12:36:21that you'll understand. So because in
12:36:22the previous previous section we have
12:36:24understood right that how you can do uh
12:36:26create uh CR create update fetch and
12:36:28everything. But in this one let's not
12:36:30only do normal fetching but as well as
12:36:32let's include search query that how you
12:36:35can implement search and how also you
12:36:37can implement filter. So let's do this
12:36:39one in the next part. All right. So
12:36:40let's create our uh services. So first
12:36:43we have our first one which will be to
12:36:45fetch all the task correct. So what are
12:36:47we going to do right? So let's create
12:36:48the function here. So I'll do export
12:36:50async function. Let's do this one as get
12:36:53admin task. So here what we are going to
12:36:55receive right. So remember now we are
12:36:57actually going to implement a search
12:36:59feature also. So what will happen like
12:37:01whenever we are going to do the API call
12:37:03so let's I can pass a query parameter.
12:37:05So what I mean by query parameter so
12:37:06something like let's say I wanted to
12:37:08search all those title of the of those
12:37:11task but the title starts with first
12:37:14something like this. So when I do this,
12:37:16so let's I wanted to call this API with
12:37:18local host
12:37:21whatever 3,000 or something and then I
12:37:23have API and then what I'm going to do
12:37:24right I wanted to pass a query params
12:37:26here. These query params will be my
12:37:28search param and here what I can do
12:37:29right I can pass a value. So that means
12:37:31what I'm simply doing that I'm actually
12:37:33implementing a search sorry function ID
12:37:36but this is my key and this is my value.
12:37:38So simply I'm telling that okay whenever
12:37:40I wanted to do a search I wanted to see
12:37:43all those support task where the title
12:37:45starts with this title or maybe it start
12:37:48with first whatever it is okay so for
12:37:50this one what I going to do right so
12:37:51let's create the type here only so I'm
12:37:53going to create one uh type so I'm just
12:37:55going to do this one as admin task task
12:37:58list and this will be my query
12:38:02okay and here what I'm going to do right
12:38:04I let's do a search and this search will
12:38:06be string and also I want to do search
12:38:08with my status. This also will be
12:38:10optional and this will be string. Now
12:38:12why optional is actually important?
12:38:13Because there is a possibility that
12:38:14sometime user want to search or they
12:38:16don't want to search. Okay. And then I'm
12:38:19also going to take one more type and
12:38:20this will be my admin task
12:38:23list response
12:38:26and this will be task and we are going
12:38:29to import task of this
12:38:32array. Okay. So what this is going to
12:38:34receive right? So this is going to
12:38:36receive query. The query will be type of
12:38:38this admin task query
12:38:41and what this is going to return. So it
12:38:43is going to return promise and this will
12:38:45be admin task query response. Okay. So
12:38:48this is what we are going to return. So
12:38:50first of all what you have to do that
12:38:51see now let's understand that how you
12:38:53can implement a proper search or filter
12:38:54functionality right whenever you are
12:38:57going to do any search functionality
12:38:59right you need to actually first trim
12:39:01that uh input that you are receiving.
12:39:03Okay, trim means we have to remove some
12:39:06unnecessary spaces from our query
12:39:08parameters. So first let's start with
12:39:10search. So I'm just simply going to do
12:39:12search and this will be so I'll do
12:39:14search query dot search. So you can see
12:39:17that we're getting dot trim. Okay. So
12:39:21this is what you're going to do or else
12:39:23I'm just going to do this one as
12:39:24undefined. Same I wanted to do for my
12:39:26status also. So this will be query dot
12:39:29search dot trim and then I'm simply
12:39:33going to do or else this will be
12:39:35undefined. So this is the first thing I
12:39:37need to do. Now very important now when
12:39:40we are actually going to do a uh filter
12:39:43with status let's say I wanted to filter
12:39:46all those task where the status is uh
12:39:49open right. So in that case what we have
12:39:52to do right because in our uh status uh
12:39:55logic so you can see that this
12:39:56particular property has fixed uh status
12:39:59here right so fixed means either it will
12:40:01be open or it will be in progress or it
12:40:03will be resolved right it will not be
12:40:05something else maybe let's say failed
12:40:07failed is not there so now let's see if
12:40:09user try to give some different value
12:40:12which value is not present so you have
12:40:13to actually return a error back so
12:40:16you're getting so now to do this one
12:40:17what you're going to do right I'm simply
12:40:19going to do okay if this status is true
12:40:22and now what we're going to do right so
12:40:24let's maybe
12:40:26uh we are going to create one let's do
12:40:28here only so I'm just going to do a con
12:40:31let's do task status
12:40:36and these will be either open right so
12:40:39we have either open or it will be either
12:40:42in progress
12:40:44or it will be after uh either
12:40:47resolved and then I'm simply we're going
12:40:50to do as constant right so these
12:40:52statuses has to be between these three
12:40:56options and if it is not there so that
12:40:58means we have to mention that and then
12:41:00I'm simply going to do if not equal task
12:41:02status dot includes the current status
12:41:05that we have right as task status
12:41:10uh what is that name task status right
12:41:16task oh we have to create one more here
12:41:18I bet so let's create one type here. So
12:41:21I'm just going to do type and I'll do
12:41:22task status and this will be so I'm
12:41:26simply going to do a type of this task
12:41:28status and this will be number.
12:41:32Okay. And this one we can use here that
12:41:34if this is not as task status. So in
12:41:37that case what you're going to do we are
12:41:39simply going to throw new error. So I'll
12:41:40throw new app error
12:41:43and I simply going to tell 400 and I'll
12:41:45do status must be
12:41:50between
12:41:52open in progress
12:41:55or result. Okay. So this is the first
12:41:59thing. So now what we going to do right?
12:42:01So first here after this we are simply
12:42:04going to create our task and let's do
12:42:07ait and I'm simply going to do find all
12:42:10task. Now this is where we are actually
12:42:12going to implement our uh DB uh
12:42:14property. So not DB properties our
12:42:16repository logic and here we are going
12:42:18to pass the search and we are going to
12:42:19pass the status and at the end what
12:42:22we're going to do we're going to return
12:42:23this task here
12:42:26this task. Okay.
12:42:29Okay this is fine. So now we are going
12:42:31to create our actual logic where we have
12:42:34to do couple of things. So first let's
12:42:36go to our admin task repository and here
12:42:39first let's create this. I'm simply
12:42:40going to do export as sync function and
12:42:44this will be find all task and here we
12:42:48are going to receive what we are going
12:42:49to receive filters. So what will be the
12:42:51filters? So we are getting search and
12:42:53status right? So we need to create a
12:42:54type. So simply I'm going to do type
12:42:57let's do admin task list
12:43:01filters
12:43:04and this will be so either it will be
12:43:06search or it will be status correct. So
12:43:08copy this
12:43:11and oh sorry here we are going to do
12:43:14this and now this will be type will be
12:43:17this and then what we're going to return
12:43:19we going to return a promise of task
12:43:22of array. So first we need to do couple
12:43:25of things right and also let's see one
12:43:27thing you have to return in this one not
12:43:30query we have to return the response
12:43:32here. So now what we have to do first?
12:43:34So first we have to create one
12:43:36condition. So I'll do conditions
12:43:40and this will be string of array and
12:43:42this will be equal to array. Also we
12:43:44need the values. So I'm just going to do
12:43:46values. Values we don't know what is the
12:43:48value. So I'm just going to do unknown
12:43:50of array and this will be equal to
12:43:52array.
12:43:54Now what I'm going to do? So first of
12:43:55all what we have to do? So we have to
12:43:57check that if currently in our URL
12:44:01search is present. We are going to push
12:44:02this search into our condition and also
12:44:05we are going to push the value into our
12:44:07values array. If status is present then
12:44:10we are going to also push the status
12:44:11into our condition and also we are going
12:44:13to push our values here also. So to do
12:44:15this one first what we'll do? So I'll
12:44:17take a param index and this will be
12:44:20equal to one. I'm simply going to check
12:44:21that if filter dot search if this is
12:44:24actually present. So in that case I'm
12:44:26going to do condition dot push and here
12:44:28we are going to write a query right. So
12:44:30title I like right and this part also I
12:44:33have covered in my uh actually uh
12:44:36posgress video uh if you have watched
12:44:38that particular section and we are going
12:44:40to pass the param index and then we are
12:44:42also going to push the values so values
12:44:44will be what? So values will be here our
12:44:48uh filters dot search. So do filter dot
12:44:51search
12:44:53that's it and then we are going to
12:44:55increase the param index by one like
12:44:57this. Similarly, we have to do the same
12:44:59thing for our status also. So, I'll do
12:45:02if filter dot status if this is present.
12:45:05So, in that case, I'm simply going to do
12:45:07condition dot push. And here we are
12:45:09going to check the status property. So,
12:45:10I'll do status is equal to
12:45:14and this will be our param index. And
12:45:16here we are going to pass value dot push
12:45:19and d will be filters dot status. Okay.
12:45:24So now based on whatever is present it's
12:45:27going to whose uh in the values values
12:45:30are important also and also in the
12:45:32condition you have to check that which
12:45:33property actually we are filtering. So
12:45:35here we are checking our title for
12:45:36status we checking our status and from
12:45:38where it is coming this is actually from
12:45:40our DB properties that we are checking.
12:45:43So now we can simply create a um where
12:45:45clause. So I'll do con and I'll do where
12:45:48clause
12:45:50and this will be the condition length if
12:45:52this is greater than zero. So I'm simply
12:45:54going to do where
12:45:56and here we are going to simply pass
12:45:58conditions dot join because if both are
12:46:01present what you have to do we are going
12:46:02to join with and okay like this. So this
12:46:06is done or else this will be empty and
12:46:08then at the end you can return the
12:46:10result. do res uh result and this will
12:46:12be avit. So we have pool dot query and
12:46:16here we're going to pass a task
12:46:18and now
12:46:22okay let's do one thing maybe it will be
12:46:24confusing so let's create like this we
12:46:26have done remember task row and this
12:46:28will be equal to our task like this and
12:46:30this task row we going to use here
12:46:34task row and now what I'm going to do so
12:46:37we'll do select
12:46:40so I'll do select ID title
12:46:44status
12:46:46user ID
12:46:49created at and updated data. So all this
12:46:52I need and now I'm simply going to do
12:46:55from
12:46:56support tasks this is my table name and
12:46:59you have to pass the web clause here and
12:47:02also now let's do order by
12:47:05created at disk
12:47:08and we are going to pass the values. So
12:47:11values will be so this is our condition
12:47:14and this will be our actual values the
12:47:16values that we have this one. So I think
12:47:19this is done and then at the end we are
12:47:21going to return result dot rows.
12:47:26So this is completed. So this is what we
12:47:28are going to do based on what whatever
12:47:29is present we add the condition that we
12:47:32based on what we are going to filter
12:47:33right and then uh we are also going to
12:47:36push the values created a wear clause
12:47:38and then just create the query. So this
12:47:40is done. So now we can go to our
12:47:42services. So here let's import this
12:47:45first. So we're passing sorry uh this
12:47:49will find all task search and status and
12:47:51then it's going to return the task
12:47:53return. So this is done. Now what we
12:47:55have to do right? So you have to go to
12:47:56our task route. So first of all this get
12:47:59admin out going to import from our
12:48:01service. This is our get admin and here
12:48:03you see that you have to pass a query.
12:48:05So how you're going to pass a query. Now
12:48:07to pass the query what you do right
12:48:09you're going to pass a request and
12:48:11request is going to give you this query
12:48:13that's it and then you can simply do
12:48:16status
12:48:18200
12:48:21uh JSON and then you'll pass the success
12:48:24it will be true and then
12:48:27you're going to pass the data. So this
12:48:29is done. So now this is actually the
12:48:31important part here. Okay. So now what
12:48:34we going to do right we need to do the
12:48:35uh check here or we are going to test.
12:48:38So first let's go to our okay let me
12:48:40just move this one here.
12:48:45Okay so first let's go to our login and
12:48:49then first I'll try to login. Okay I'm
12:48:52not running maybe. Okay I got it because
12:48:55I'm actually recording after some time.
12:48:58So I have to start again. So now let's
12:49:01check what we passing. We are passing
12:49:03body sumgmail.com
12:49:06send this we're getting the token so
12:49:08first check this okay so I'll go here uh
12:49:10and then in the headers I'll just check
12:49:13that okay what is this uh user
12:49:21send this okay this is a normal user I
12:49:24think we have created one more user
12:49:26right I think that is John I remember
12:49:29let's send I think this is the admin
12:49:31user because we need to check the admin
12:49:33user also and then now let's try to send
12:49:36this one
12:49:39okay so this is admin right so now first
12:49:41of all what I'll do right so let's
12:49:43create one here so this will be get
12:49:46right so go here copy this API till this
12:49:50part
12:49:52so API now let's go to our index so we
12:49:56have / API/ admin / task correct so /
12:50:00admin/ as tasks. Okay. So now first of
12:50:04all I try to send access token is
12:50:06required. Now what I'll do right I'll go
12:50:07to login and I'll try to login with my
12:50:10normal user. Okay. This is very
12:50:11important. So try to send and you'll see
12:50:14that I'm just going to copy this and
12:50:17let's go to our headers. So add
12:50:19authorization. Let's add our beer.
12:50:25And then you see what will happen. Try
12:50:26to send admin access is required and you
12:50:29do not have admin access. It seems
12:50:30fantastic right? So that means this
12:50:33particular line now is actually able to
12:50:35understand that okay this actually need
12:50:37a admin access because this also need
12:50:39authenticate as well as require admin.
12:50:41So now if I go to login and try to login
12:50:44with my admin user get the token
12:50:48and now I try to go here and try to
12:50:51replace this
12:50:53and try to send that's it. So you're
12:50:56getting this one. Now what I'll do right
12:50:57so maybe
12:50:59uh maybe let's do one thing we have a
12:51:01title first open task and status is open
12:51:04correct so maybe I'm just going to login
12:51:07with a normal user okay so I'll try to
12:51:09send I'll get the token
12:51:12and then go to our uh where is that post
12:51:15right so your body second support task
12:51:18let's try to add one more here
12:51:23try to create so it's created so now if
12:51:25I go here and try to send. So you're
12:51:27getting two, right? So now let's see how
12:51:29we are going to uh test. So first of
12:51:32all, let's say I wanted to check the
12:51:34title of the second one only. So what I
12:51:36can do, right? I can pass a query here.
12:51:38So see I'll do this and see here we have
12:51:40a query paramedic and I'm just going to
12:51:42do a search. So you can see that the key
12:51:44is value is search and search is equal
12:51:46to I'm going to do second. Okay. And now
12:51:48try to send okay status must be okay.
12:51:52Why this is coming? Status must be
12:51:53between open in progress and result.
12:51:55This should not come.
12:52:00Oh, this will be status. See, this is
12:52:02the problem because you given for both
12:52:03sim. So now try to send and you can see
12:52:05that you're only getting the second
12:52:07support. Now I'll do first. Try to send.
12:52:10You're getting only first, right? And
12:52:12also you can do with status also. Let's
12:52:15say I'm just going to do status and I
12:52:17wanted to check the open status. So I'll
12:52:19do status and this will be open like
12:52:21this. Okay. Try to send you're getting
12:52:23get both. And now change this one to
12:52:25maybe result
12:52:27right and try to send you're getting
12:52:29empty right if you try to send in
12:52:31progress.
12:52:33Try to send you're getting empty. Okay.
12:52:36Now let's say you can uh send both. So
12:52:38how you going to send both? Let's say
12:52:39you wanted to add search. Search will be
12:52:41second. And then if you want to add both
12:52:44you have to give and here and see that
12:52:45one mode will be added here and this
12:52:47will be status equal to open. So
12:52:49basically I'm telling that give me all
12:52:50the support task where the title is
12:52:53second and status is open try to send
12:52:55you're getting only one fantastic right
12:52:58so with this now easily you will be able
12:53:01to implement search and filter logic
12:53:02also okay so with this now let's move on
12:53:04to the next one so next one will be how
12:53:07admin can update task status so that we
12:53:09are going to do in the next part all
12:53:11right so now next one will be so we need
12:53:13one more route here that admins should
12:53:15be able to update the uh update task
12:53:17status
12:53:18Okay. So, first let's do admin task
12:53:21router patch. I think I'm not explaining
12:53:23again because you uh I hope that you
12:53:26know that when we are updating only
12:53:27certain portion we don't have to do like
12:53:29post and everything right. So we need
12:53:31only patch. Uh so here I'm simply going
12:53:33to take the task ID because we need to
12:53:35know which task we are updating and then
12:53:38we have to tell look at this will be my
12:53:39status of update. So here I'm simply
12:53:41going to do a sync. We'll do request
12:53:43response
12:53:46and next
12:53:49correct. So now let's take a try catch
12:53:57call the next with error. So in this try
12:54:00first now this will be simpler. Okay. So
12:54:02it will be const and then I'm simply
12:54:04going to d it. Let's give this one as
12:54:06update admin task status.
12:54:11Okay. and we going to send something
12:54:13here. So you'll understand what actually
12:54:14we need to send. But first let's create
12:54:16our services. So I'm simply going to do
12:54:18export async
12:54:21function and I'm simply going to do
12:54:23update admin task status. So what you
12:54:26need? So first of all you need the task
12:54:27ID correct which will be what string and
12:54:30then you also need to know status. Why
12:54:32I'm keeping unknown extremely important
12:54:34because we don't know what value user is
12:54:36sending from the UI side. Let's say in
12:54:38the UI side you have a drop-down then
12:54:39user don't have any other option they
12:54:41needs to select those but let's say in
12:54:43the UI side they have input text and
12:54:44they can put any value right so that
12:54:46should not happen so in that case we
12:54:48have to give a check here so I'm just
12:54:49going to give a promise of task
12:54:52so I'm going to give this check this one
12:54:54okay so copy this
12:54:57paste it here somebody is simply going
12:54:59to tell that if this type of
12:55:02status is not equal to equal to string
12:55:07And if not equal to task status includes
12:55:10status as task status. So I'm simply
12:55:12going to tell that status must be
12:55:13between open in progress or result.
12:55:16Right? So this is the first thing. Now
12:55:19after this I'm simply going to do con
12:55:21task and this will be ait update task
12:55:25status
12:55:28and this will be our task state id and
12:55:31status both you have to pass. Okay. if
12:55:34this task is not present. So in that
12:55:37case we're going to throw
12:55:39new app error 404
12:55:43and I'll do task not found and then I'm
12:55:47simply going to return the task.
12:55:52So here now first let's go because from
12:55:54our routes you need to import this. So
12:55:56import this
12:55:58here and then what you have to pass. So
12:56:00first you have to pass the task ID. So
12:56:02how you're going to get the task id? So
12:56:03you're going to get from request
12:56:05dotparams dot task id and then what you
12:56:08have to you have to pass the actual
12:56:10status. This actual status from where
12:56:12you're going to get see this part we've
12:56:14already done multiple times. So you're
12:56:16going to get from your from your request
12:56:18body. So request body dot status. Okay.
12:56:22And now what you can do right you can
12:56:23simply return the responsible race dot
12:56:25status of 200
12:56:28dot JSON and I'm simply going to do
12:56:31success will be to data will be uh the
12:56:35task that we are getting. So this is
12:56:38fine. Now we have to create our
12:56:40repository. Repository means we have to
12:56:42create our actual task to update the
12:56:44task. Right? So first let's go here and
12:56:47then we'll do export
12:56:50function this.
12:56:53So we'll get the task ID which will be
12:56:55string
12:56:57and status and this will be string. Why?
12:57:00Because here we are already checking if
12:57:01it is not string. So that means if it is
12:57:03not string in this case so we can
12:57:06actually uh like take this one as a
12:57:08string here because we already have a
12:57:10check. So that is the reason giving all
12:57:12or adding all these checks are very
12:57:13important. So now what you have to do?
12:57:15So you have to return a promise of task
12:57:18or this can return null also it's
12:57:20possible. So now just write the query
12:57:23right. So we'll do con result. So we'll
12:57:25do a pull dot query and here I'm simply
12:57:29going to pass a task row and now we can
12:57:32simply create it. So I'm simply going to
12:57:34do select sorry what I'm doing man
12:57:38update. So the update support tasks. So
12:57:41here we are simply going to tell set
12:57:43because we're updating status property
12:57:45right. So status will be equal to one.
12:57:49Now also I think you already know we
12:57:51need to update the updated at property
12:57:52also which will be now current time and
12:57:55then what we going to do where the id is
12:57:57equal to this because based on the ID
12:58:00only you have to understand that what
12:58:01actually we have to update. So do
12:58:04returning we need that id title status
12:58:08user id created at and updated at
12:58:14okay and then we can simply pass out. So
12:58:17first one will be your status status
12:58:19will be the status and id will be your
12:58:22task id and then we are going to return
12:58:26result dot rows of oh I think I have to
12:58:30do let's keep result only. So do result
12:58:33dot rows of zero or else this will be
12:58:36null. So save this and now we can do
12:58:39just import this from here.
12:58:42What I'm doing man we're getting status
12:58:51but we are already giving check here if
12:58:53type of status is not equal to string.
12:58:57Oh we have to give or
12:59:00that is the reason. So if it is not
12:59:02equal to string or if this is the case.
12:59:04So now I think this should work. Okay.
12:59:07So to check this what we can do. So
12:59:09first of all let's say let's do one by
12:59:11one. Okay. So first I will go to my uh
12:59:14let's go here. Let's try to get all the
12:59:16task. So we're getting two task. Let's
12:59:19create one more. So this will be patch.
12:59:23And now what I'm going to do right will
12:59:25copy this.
12:59:27And let's say I wanted to update this
12:59:29particular second task status from open
12:59:32to in progress or result. So I'm going
12:59:34to copy this
12:59:36uh paste it. Then I'll do status. But
12:59:38see what I'll do. I'll go to body and
12:59:40I'll try to send the status as random
12:59:45value. Okay. Let's do one by one. So
12:59:47first we'll be getting what token is
12:59:49required. Access token is needed.
12:59:51Fantastic. Now let's go to login and try
12:59:53to login with the normal user. Send
12:59:56this. Get the token.
12:59:59Go here. Go to headers. Add
13:00:01authorization. Add beer. And now see
13:00:05that you're going to get admin access is
13:00:07required. Fantastic. Now we'll go here.
13:00:10And then I'm just going to login with my
13:00:12norm uh admin user. Get the token.
13:00:17Go here and change the token. So do be
13:00:21error
13:00:23and see what will happen. send this
13:00:25status must be between open in progress
13:00:27and result. So that means you just can't
13:00:29pass any random value. So now I'm just
13:00:31simply going to do in progress. Let's
13:00:32say I wanted to do in progress. Send
13:00:35this updated this is in progress. Now
13:00:37you go to get and try to send this again
13:00:40and you're going to get in progress.
13:00:42Fantastic. So that means update is now
13:00:44working. See the main idea of creating
13:00:46this project. You have to understand how
13:00:47you can implement CRUD especially what
13:00:49is the authentication middleware. What
13:00:52is RBC means? ROB based access control.
13:00:54For example, just now we have done
13:00:55right. So see if you're a normal user,
13:00:56you can't update the status only admin
13:00:58can update status. Okay. So now see with
13:01:01[snorts] this we actually have completed
13:01:03our CR section. I think we have done
13:01:05almost all the things enough thing that
13:01:07you should know. Okay. I know that we
13:01:09haven't covered so many complicated
13:01:11things like pagination and so many other
13:01:13logic there but I think it's not
13:01:14possible to include each and everything
13:01:15in a single video. But with this so what
13:01:18will be the next step? Now this is
13:01:21actually now things will be very
13:01:23interesting. Okay. So listen carefully
13:01:25what I'm going to say. Next part what
13:01:28I'm going to do right I will be adding
13:01:30my uh I think that is I think recently I
13:01:32created I think 2 3 weeks back I created
13:01:35a radius video that particular video
13:01:38that I'm going to add in the next part.
13:01:40So it will be around 2 hours. It is very
13:01:42very very important. Again if you really
13:01:44want to learn NodeJS properly I will
13:01:46highly recommend just like I mentioned
13:01:48in the postgress right please watch the
13:01:50radius video also because in that
13:01:52particular video you are going to
13:01:53understand radius concept radius basics
13:01:56and also how you can use radius in a
13:01:58real NodeJS project. Now why this is
13:02:00very important because in this
13:02:02particular project now we are going to
13:02:03implement our file upload feature. Now
13:02:05in the file upload feature we are not
13:02:07going to only have file upload we are
13:02:08going to have file upload plus radius
13:02:11plus we are going to have background
13:02:13job. we are going to use boolean q right
13:02:15so this is the reason you need to watch
13:02:17the next section and there is a reason
13:02:20why I'm adding all of these okay so
13:02:21don't think like this is just like I'm
13:02:23randomly adding all these video if that
13:02:25is the case I already have let's say
13:02:26five or six nodejs videos I I think I
13:02:29should have added each and everything
13:02:30and this video will be 50 hours long
13:02:32doesn't work like that so that is the
13:02:34reason decided to add only postgress and
13:02:36the radius part because it's actually
13:02:37important if you don't cover or don't
13:02:39watch that section you will not be able
13:02:41to understand because I'm not going to
13:02:42covered basics in this one. Okay, this
13:02:44will be only practical and I'm going to
13:02:46give you the basic idea that how you can
13:02:47implement radius and bul MQ and
13:02:49implement background job and background
13:02:51workers. So I'm repeating once again
13:02:53next part will be radius complete
13:02:54dedicated section watch that particular
13:02:58section and then you can directly jump
13:02:59to the timestamp and you can implement
13:03:01the this particular project the rest
13:03:03whatever is left. So what are the things
13:03:05you have to do? You have to do file
13:03:06upload radius implementation and booq in
13:03:09the next part. Hey everyone welcome
13:03:11back. So in this particular video we are
13:03:12going to cover each and everything that
13:03:14you need to know to start your journey
13:03:16with radius. Now this is a completely
13:03:18practical project based video and for
13:03:22this one we are going to use a uh NodeJS
13:03:24and express application and we are going
13:03:26to use docker and posgress as our DB.
13:03:28Now before [snorts] I'm going to discuss
13:03:30the curriculum as usual I wanted to
13:03:32mention one uh important point and that
13:03:34is you can see that I clearly mentioned
13:03:35that if this particular video gets more
13:03:38than 2,000 likes because I'm getting so
13:03:39many request I'm going to create uh
13:03:42another video on posgress that will be
13:03:44advanced part two and also radius part
13:03:46two where I'm going to cover some of the
13:03:48uh more advanced topics like sessu
13:03:51background jobs and all the other
13:03:54products and level patterns that you
13:03:55need to know and also please like this
13:03:58video comment comment any possible if
13:03:59you can share with your friends it will
13:04:01be very very helpful so what are the
13:04:03things that we are going to cover so
13:04:04first we'll start with what is radius
13:04:07why actually we need it and if I go to
13:04:10the details you can see that I added all
13:04:11the details that why radius is used as
13:04:13first inmemory data store where radius
13:04:16fits in a real backend project right the
13:04:18difference between radius and the normal
13:04:20database and all the other things then
13:04:22we are going to start with adding radius
13:04:25to our backend project as I already
13:04:27mentioned we are going to use a NodeJS
13:04:28project. So you're going to understand
13:04:30how you can start Radius locally with
13:04:32docker install radius client package
13:04:35create reusable radius connection file
13:04:37and also we are going to understand very
13:04:39very important thing that radius as the
13:04:41first inmemory layer that we are going
13:04:43to use in this backend project. Then we
13:04:46are going to understand a complete
13:04:48dedicated section on radius data type.
13:04:50So you're going to understand hashes,
13:04:52list, sets, sorted list at the beginner
13:04:55level. How you are going to use counters
13:04:58using radius commands and then all these
13:05:01concepts we're going to apply in our
13:05:03backend project. Okay. So that will be
13:05:05another dedicated section where we are
13:05:07going to add radius caching to our
13:05:08product APIs. Moving to the next one
13:05:11which will be another important section.
13:05:12We are going to understand cash
13:05:13invalidation still cash problem. Right?
13:05:16So here we are going to use cast asset
13:05:18pattern. understand cash uh issue
13:05:21invalidate uh patterns right so there
13:05:23will be lot of things we are also going
13:05:25to understand or we are going to have a
13:05:26dedicated section on TTL okay then uh we
13:05:30are going to have another section on uh
13:05:31how you can implement rate limiting with
13:05:34radius and at the end we are going to
13:05:35end this particular video with pubsub or
13:05:37how you can actually implement uh
13:05:40publish and subscriber pattern using
13:05:42radius so this is what we are going to
13:05:44understand in this particular video I'm
13:05:46pretty sure you're going to learn a lot
13:05:49things and as usual the source code will
13:05:51will be added in the description so you
13:05:53can download from free from my website
13:05:56and also I wanted to mention I think
13:05:57most of you already aware that I am
13:05:59planning to launch a huge course on my
13:06:02uh website that is not yet live so if
13:06:04you want you can join the weight list
13:06:05that is completely free so you can see
13:06:07that almost more than 4,000 people
13:06:09already joined so with that [snorts] now
13:06:11let's get started and good luck all
13:06:13right so now let's get started see the
13:06:15first thing I wanted to mention that
13:06:17this video is not for complete
13:06:18beginners. So what I mean by this, you
13:06:21should have at least some idea on node
13:06:23express. Okay. And also some basic idea
13:06:26how usually docker works, how we can
13:06:28create docker compos file and some of
13:06:30the very basic concepts like how you can
13:06:32create controllers, services, express
13:06:35routes, some of the postgress queries.
13:06:37Now why this is important? Uh so first I
13:06:39wanted to mention because see if you
13:06:42don't have all of these right, it will
13:06:43be very difficult for you to understand
13:06:44this particular project. Why? So this is
13:06:47a completely practical project. So what
13:06:48I mean by practical? So as you can see
13:06:50that I have a project created. Okay. So
13:06:53here we already have all the routes and
13:06:54everything. So we're not going to write
13:06:56each and every logic because this course
13:06:59is going to only on radius. So what we
13:07:02going to do? We are only going to apply
13:07:04the radics related concepts practically
13:07:07and by implementing practically we are
13:07:09going to learn the concepts. I hope
13:07:10you're getting and also before we'll
13:07:12implement the concepts we are going to
13:07:14have some kind of conceptual and some
13:07:15very small examples so that you can
13:07:18understand that okay what uh that
13:07:20particular concept is and where you are
13:07:22going to apply that particular uh
13:07:23concept in a real project. So first
13:07:26before uh we will jump into radius
13:07:30concept first you have to understand the
13:07:31project structure that what actually we
13:07:33are using here. Okay. So as you can see
13:07:35that we have a simple uh node express
13:07:37project. So for this one we're using
13:07:39docker with posgress. So for our DB so
13:07:41you can see that in the docker compose
13:07:44we just have a service. So this is our
13:07:46image container name uh the username
13:07:50password and blah blah all the other
13:07:51things right. So we have the port
13:07:53volumes and you can see that all these
13:07:54details also have added in the env right
13:07:56so we have a database host database port
13:07:59database user database password database
13:08:02name. Okay. Now what I'm going to do
13:08:04right, I'm going to add this starter
13:08:06code in the attachment. Very very
13:08:08important. First you have to download
13:08:09this and then on top of this starter
13:08:12code you are going to implement all the
13:08:14logic that we are going to do. Now next
13:08:16will be so let's start with the first
13:08:18one. So you can see that we have a DB
13:08:19folder we have a pool. DS. So here we're
13:08:21just creating the connection pool.
13:08:24Right? So we have the new pool from the
13:08:26pg package. We have av package and
13:08:28before that also I want do. And if you
13:08:30go to package.js JS and you can see that
13:08:32we have chords envir and pg and we have
13:08:35a start uh script db migrate that I'm
13:08:38going to explain and the db sid uh so
13:08:41what this is going to do this is going
13:08:43to do the migration right this script
13:08:45and then we have a simple dummy data
13:08:47that I have created that we are going to
13:08:48use a demo products and this is going to
13:08:52seed this particular data in your
13:08:53posgress db next let's move on to the
13:08:56services so what services is going to do
13:08:57services is actually going to interact
13:08:59with your posgress DB. So that is the
13:09:02reason first we have a get all products
13:09:04which is going to fetch all the
13:09:05products. Then you have get product by
13:09:07ID uh and then create product and update
13:09:10product. So if you go to the postman so
13:09:12you can see that we have all these
13:09:13routes. We have a health route products
13:09:15to fetch the products right and then we
13:09:18have the products uh filter products by
13:09:21ID creating a product and updating a
13:09:23particular product. Next move on to the
13:09:25controllers. controller is nothing but
13:09:27your uh logic where we are going to
13:09:29actually return our response back. Let's
13:09:31say we are having some front end. Uh so
13:09:33I'm not explaining all of this. If you
13:09:34have some idea, you'll understand what
13:09:36actually this thing is doing. And this
13:09:37is also going to call the product
13:09:39service, right? Then uh we have a simple
13:09:41middleware and then the routes file. So
13:09:43routes file is going to have your
13:09:45products related routes file and one
13:09:48index dot ts file which is your root
13:09:51route file. And this root route file we
13:09:53are going to use where we are going to
13:09:54use in the app.ts ts file right so you
13:09:56can see that we are using creating the
13:09:58express application using the course
13:10:00using the express json middleware using
13:10:02the routes and then exponing the app and
13:10:04this app we are going to use in our main
13:10:07file so this is our main root file right
13:10:09serverts we are starting the server we
13:10:11are creating or testing the DB
13:10:13connection and then you can see that we
13:10:15are listening to this particular port so
13:10:17this is very very important to
13:10:19understand this uh project structure or
13:10:21else it will be difficult for you to
13:10:24understand that what actually we are
13:10:25going to do in the next section. Now
13:10:26remember as I already mentioned this is
13:10:28a radius course. We are not going to
13:10:31write too many logic and everything and
13:10:33we're not going to go into too much
13:10:34advanced details for now but the uh
13:10:37information that I'm going to give you
13:10:38is going to give you enough information
13:10:40to get started with radius. So what will
13:10:43be the next step and what structure we
13:10:45are going to follow. So first of all
13:10:47what we need to do right. So let's uh do
13:10:49one thing let's install the radius
13:10:51package first we have to do that. So
13:10:53what I'm going to do right so let's go
13:10:55here and then I'm just going to do we
13:10:57haven't started anything that what is
13:10:58radius and everything that we're going
13:11:00to do. So first download the starter
13:11:02code very important okay if you don't do
13:11:04it it will be difficult I'm repeating
13:11:06again and again download it and then we
13:11:08are just going to do npm install radius
13:11:11and this you have to do on the root
13:11:12that's it okay so this is going to
13:11:14install the radius package this is done
13:11:17so now first of all we have to
13:11:18understand that what actually radius is
13:11:21and why actually we need radius right so
13:11:23this is important because uh this is a
13:11:25very important interview questions also
13:11:27why because when you have something
13:11:28called post or let's say you're using
13:11:30some different DB why actually you need
13:11:32radius so first of all you you are going
13:11:34to write that radius is nothing but your
13:11:37in-memory data store right so this will
13:11:39be your in-memory data store okay now
13:11:44what is the meaning of this so if you go
13:11:45to here right so let's always try to use
13:11:48this AI mode okay side by side or you
13:11:49can use some chat GP and everything it's
13:11:52very helpful okay so if you are watching
13:11:54a video and at the same time make use of
13:11:55these tools it will be very very easy so
13:11:59here you can See the words telling that
13:12:00okay it's a inmemory nosql data
13:12:02structure something like that but we
13:12:03have to understand that what actually in
13:12:05memory means so that simply means the
13:12:08radius that we have right it's going to
13:12:10keeps your data in RAM okay
13:12:13[clears throat] you're getting so it's
13:12:14going to keeps data mainly in RAM so
13:12:19what will happen if we have something in
13:12:21RAM so in a simple way the read and
13:12:23write operation will be extremely fast
13:12:26or very fast right so read and write
13:12:28operations questions will be very fast.
13:12:32So this is one of the main reason. Now
13:12:33why actually you need ready? So what are
13:12:35the best use cases interview questions
13:12:38right? So for example let's say we want
13:12:39to implement some kind of cash. So here
13:12:42okay let me just give here. So we want
13:12:44to implement some kind of cash. It's
13:12:46very important right? Let's say we have
13:12:48to implement some kind of rate limiter.
13:12:50I'm giving very basic example. Okay
13:12:52there are so many advanced use cases
13:12:54radius can have. Let's say you want to
13:12:56implement some kind of message broker
13:13:00right or uh maybe okay let's say you
13:13:04have a normal database right so in our
13:13:05case we're using postgress now we want
13:13:08to implement or we want to keep some
13:13:10kind of temporary first layer in front
13:13:12of our existing database so it's like
13:13:15something like this so we have a temp
13:13:16first layer in front of our normal
13:13:22database or main database right
13:13:25So these all will be the use cases. Now
13:13:29now the next question will be why radius
13:13:31is used even though we have a normal
13:13:33back end right for example in our case
13:13:35we're using posgress right extremely
13:13:37important concept you can't uh skip all
13:13:39of these so even though our normal
13:13:43database is what it's actually for your
13:13:46permanent structured data. So whatever
13:13:48database you're using that is for your
13:13:51permanent structured
13:13:54data right what radius is going to do
13:13:57right so there can be some task that
13:14:00whatever application that we are
13:14:01building that we need to have some kind
13:14:03of speed
13:14:05or some kind of temporary data and this
13:14:09is where radius can be helpful right so
13:14:11this is where radius can be helpful how
13:14:13so it can be for example let's say we
13:14:15have a product list and I want to c that
13:14:18product list. So caching product list.
13:14:21So this is where you need radius or
13:14:23let's say you want to count some kind of
13:14:25product views. How many views are there
13:14:28for that particular product or you want
13:14:30to limit that how many request
13:14:34a particular user can do right or can
13:14:37make
13:14:39or you can do running background checks
13:14:41uh sorry background jobs also running
13:14:43background jobs. So this is where you
13:14:44need radius. What radius? Radius is
13:14:47going to help. So it's going to help
13:14:48with this particular kind of task. Why?
13:14:51As I already mentioned, it's going to
13:14:52store the data in your RAM. It will be
13:14:54much faster for your sort lived. Sort
13:14:57lived. Okay, this is not permanent data
13:15:00or your frequent frequent accessed data.
13:15:05So this will be the main reason why we
13:15:07need this. Okay. Now what is the
13:15:10difference between? So as I already
13:15:12mentioned right it is a inmemory data
13:15:13store but what posgress usually do? So
13:15:15Postgress is our normal DB, right?
13:15:18Postgress is going to store the data.
13:15:20It's going to store the data where in so
13:15:23on disk. Okay. Why? Because this is a
13:15:27long-term storage versus radius is going
13:15:30to store in memory. Okay. So in RAM so
13:15:33it will be much faster. So if someone
13:15:36ask you okay what is the one single
13:15:37reason of using radius? Now remember the
13:15:40there can be so many reasons but number
13:15:43one reason will be the speed right. So
13:15:45the accessing of data will be much
13:15:47faster. So this would be the very basic
13:15:51definition what what is radius why
13:15:53actually we need radius even though we
13:15:55have a normal database right very very
13:15:57important concept all these so now what
13:16:00we going to do right so first of all
13:16:01let's do one thing we are going to do in
13:16:02a different way so first we are going to
13:16:05understand some of the very basic things
13:16:07for example some of the radius data
13:16:09types we have to understand so what we
13:16:12can do right so directly you can create
13:16:14a examples folder so that is the reason
13:16:16I mentioned that please create this uh
13:16:19uh sorry please for the uh download not
13:16:21for download the startup project it's
13:16:23very helpful okay so here I'm just going
13:16:25to do this one as radius data types and
13:16:29I'm not going to spend too much time on
13:16:31explaining so many things let's keep
13:16:32this whole uh video very very p
13:16:35practical and we'll see that it will be
13:16:37very easier for you to understand all
13:16:39right so first of all what we need to do
13:16:41right so we need to do something we need
13:16:44to add our uh radius image in for uh
13:16:48docker combos correct so first of all
13:16:50what are you going to do so let's add it
13:16:52here so let's add one more here so I'm
13:16:56just going to do this one as radius and
13:16:58here what I'm going to do so this will
13:17:00be so I'm just going to add a image so
13:17:01what will be the image so for this one
13:17:03I'm just going to do radius colon 7 so
13:17:06let's use radius 7
13:17:10and here I'm just going to use the
13:17:11container name so let's give this one as
13:17:14radius
13:17:16uh ports radius something like this
13:17:18whatever you want to give I'm going to
13:17:20do restart and this will be unless
13:17:23stopped
13:17:25okay let's use the ports so normally
13:17:27radius uses this 63 79 port okay so this
13:17:31is what we are going to map and then we
13:17:34are also going to have a volumes
13:17:37so for volumes this will be my radius
13:17:41data and here I'm just going to do /
13:17:44data and here we're going to have the
13:17:45radius
13:17:47data. Okay, so this is what we need.
13:17:51Okay, so this will be the first thing.
13:17:52So what are you going to do, right? So
13:17:54let's go here.
13:17:56So I'm just going to do docker compose
13:17:59down and then I'll docker compose up -
13:18:04d.
13:18:07Okay, so what you're getting uh
13:18:10networking this is already in used.
13:18:12Okay, so you're already using this.
13:18:16Maybe let's use this one. Change this
13:18:18one to some different code
13:18:22and then run once again.
13:18:25Okay, so it's running. So let's verify
13:18:27once
13:18:30go to image. Okay, we have ready. This
13:18:33is running. So now what we need to do,
13:18:35right, we also need to add this in our
13:18:37env. So in our env we don't have. So
13:18:39what we're going to do, right, I'm just
13:18:40going to add one more. So let's do this
13:18:42one as radius_l
13:18:44and this will be radius and this is
13:18:47running on local host col 6380
13:18:52right whatever port you are using that
13:18:54you have to use it so using 6380
13:18:57so now I think this is done so first of
13:18:58all what we are going to do first we
13:19:01will understand the basic radius data
13:19:03types or else we can't directly jump to
13:19:06the practical part okay very important
13:19:08all right so I'm just going to explain
13:19:10that what are the things we're going to
13:19:11learn. Okay. So, first I'm just going to
13:19:14So, here I'm just going to write. So,
13:19:15we're going to uh learn about string.
13:19:18Let's do has also I'm just going to
13:19:22let's do list set. There are so many.
13:19:25Okay. Then you have something called
13:19:27sorted
13:19:30sorted set and then you have TTL. Okay.
13:19:33So, these all the things we are going to
13:19:35understand. At the same time, I'm also
13:19:37going to give you the basic concept side
13:19:40by side and you'll see that how much
13:19:41easier it would be for you to understand
13:19:43all of these. So let's do this one in
13:19:45the next part. Okay. So let's start with
13:19:47string, right? So we have strings. So
13:19:49what is a radius string? The definition
13:19:52will be radics uh radius string stores
13:19:56one value under one key. Okay. So this
13:19:59usually stores
13:20:02one value under one key. Okay, what are
13:20:06the things that it can store? Right. So
13:20:08for example, first of all, plain text if
13:20:11you want to store. Next, it can also
13:20:14stored numbers
13:20:16stored as text. Okay, so these two and
13:20:20also something like counters.
13:20:23So this will be very simple definition.
13:20:25Now what will be the example? Let's say
13:20:26you have a key, right? So your key is
13:20:29something like we are let's say you're
13:20:31uh counting some page views that how
13:20:34many views this particular page gets
13:20:36something like that very simple example.
13:20:38So there will be some key okay so let's
13:20:40say this key is your page views and then
13:20:43there will be one value very very simple
13:20:45to understand and this value will be
13:20:47let's say it's 100 something like this
13:20:50okay so that is the reason I mentioned
13:20:52it's going to store one value under one
13:20:54key okay so now let's understand this
13:20:58one with a very simple example so first
13:21:00of all what we going to do we already
13:21:02have enval so I'm just going to do env
13:21:05from dot
13:21:07env and also we are going to import
13:21:11something
13:21:12from our radius package. So just now we
13:21:14have installed radius. So what are the
13:21:16thing what actually we need here? So we
13:21:18need to create a connection. So we need
13:21:20to import create client. Okay. So first
13:21:23what are we going to do right in our in
13:21:25view this rad whatever code that you are
13:21:27running and then what you're going to do
13:21:29first. So first we need to load the
13:21:31config. So I'll do.config.
13:21:33So this will be the first thing. And now
13:21:35we need our radius connection URL that
13:21:38we are going to use to create the
13:21:39connection. So I'm just going to do con.
13:21:41So I'll do radius URL and this will be
13:21:44equal to. So we'll do process env dot
13:21:47and we have our radius url right or else
13:21:50you can just simply directly pass this
13:21:52one here also. So copy this and then
13:21:55we're going to pass it here. So now what
13:21:57we need to do we're going to create one
13:21:58radius client. Okay. Why actually you
13:22:02need radius client if someone ask you.
13:22:04So radius client will be our main
13:22:06connection that we need so that we will
13:22:08be able to connect to radius. So I'm
13:22:10just going to do con radius. So this
13:22:12will be a create client and this
13:22:14actually you need the URL. Okay. So this
13:22:16is going to do the connection and what
13:22:18will be your URL? Your URL will be rad.
13:22:21So this is going to create the
13:22:22connection. So first of all what we
13:22:24going to do first? I'm just going to do
13:22:26a sync function and this will be run.
13:22:29And here first we need to see that if we
13:22:32are able to open the connection to our
13:22:35radius server or not. So I'll do open
13:22:37connection
13:22:38to radius
13:22:41server right. So how we going to do
13:22:43that? So this we have it and this radius
13:22:46instance that we have created this one
13:22:48right so here this is going to give a
13:22:50connect method and this is going to do
13:22:52the connection and then I'm simply going
13:22:54to do a console.log log and I'm simply
13:22:57going to do connected to radius because
13:23:00this we need to see and also I'm just
13:23:03going to do console.log log and let's
13:23:05say I'm just going to check the ping and
13:23:07this ping will be a so you have the
13:23:09radius dot ping right so this is going
13:23:13to uh explain us sorry not explain this
13:23:16is going to tell us that okay if the
13:23:18connection is successful or not so now
13:23:21what are going to do so this will be a
13:23:22promise so do run dot catch in case any
13:23:25error so we're going to get the error
13:23:28and then I'm simply going to do console
13:23:31dot error and I'm Just going to do demo
13:23:35or maybe let's what let's do demo field
13:23:37because we doing the demo right here. So
13:23:39demo field and this will be error and we
13:23:42are just going to exit from this
13:23:43process. So do process doexit will be
13:23:46one. So let's save this. So we we are
13:23:50not doing anything else here. Okay.
13:23:51We're not adding the example of string
13:23:53that we are going to do. So go to
13:23:55package dojson and then I'm just going
13:23:57to maybe let's do a example colon and
13:24:00I'll do radius types. So how we are
13:24:04going to run it. So this will be tsx and
13:24:08I'm just going to do so we have to do
13:24:10example right? So you have to go to
13:24:12examples because this is what we are
13:24:14using / the radius data type.ts. So I'll
13:24:18do radius data type not types.ts.
13:24:23So this will be our command that we are
13:24:25going to use directly in the terminal.
13:24:27So if I now open this let's clear it and
13:24:31I'll do npm run enter and you can see
13:24:35that it's now connected to radius and
13:24:37you're getting ping and this is the
13:24:39pong. So that means the connection is
13:24:41now successful and see this is the
13:24:43reason I when I usually it is right I
13:24:45use use docker because docker is if you
13:24:48have ID on docker it's very very easy to
13:24:50use and also using docker you can do lot
13:24:53of things okay see how much easier it is
13:24:55to understand that whether the
13:24:56connection is successful and if it is
13:24:58working or not but one thing you have to
13:24:59be make sure that you using correct
13:25:01ready URL here if you're doing any
13:25:03mistake it's going to fail so this is
13:25:05done so now let's start with uh what we
13:25:09have to do Okay, so let's start with
13:25:10some very basic string example, right?
13:25:12So we'll go here and then I'm just going
13:25:14to do strings
13:25:17and first let's do one thing. What I
13:25:19usually mention that there will be one
13:25:21key and for one particular key it's
13:25:23going to hold one particular value,
13:25:26right? So we're going to take a string
13:25:27key. Okay, so I'm just going to do
13:25:29string key and this will be maybe let's
13:25:32say I wanted to do get some page view.
13:25:34So I'm just going to do demo page views
13:25:37something like this and then what I'm
13:25:40going to do right I'm just going to do a
13:25:42and now we are going to use some methods
13:25:44that you have to understand. So what
13:25:45method we are going to use we're going
13:25:46to use a set method. So set method it's
13:25:49going to store that particular value
13:25:51under this key. Okay. So how we going to
13:25:53do that? So it's very simple. So do
13:25:55radius dot set
13:25:57and here you have to give what you have
13:25:59to give the key which is radius
13:26:00argument. So key is this and then we'll
13:26:03give the value right. So let's give this
13:26:05one as 100. So this is how you can set a
13:26:08particular value based on one key. Okay.
13:26:10I'm repeating this thing again and again
13:26:12that set is going to do what? It's going
13:26:14to store one value under one key. Okay.
13:26:18Now let's say I wanted to get this value
13:26:19or I wanted to read this value. So how I
13:26:22can do that? So now I'm simply going to
13:26:24do okay let's take the page views. So
13:26:26this will have it. Now I'll do radius
13:26:29dot get. And what it was it was a key.
13:26:31It's very simple. So we'll do strings
13:26:33key and then let's do a log. So I'll do
13:26:35console dot log and let's [snorts] take
13:26:38the page views. So now let's save this.
13:26:41Now what we can do right uh let's
13:26:44close this and I'll clear it and then
13:26:48run once again and we'll see what you're
13:26:50getting. So we're getting 100. Okay. Now
13:26:52what you can do right you can use
13:26:54another property uh on strings and that
13:26:56is called increment. insert something
13:26:58like incr. Okay. So what it's going to
13:27:01do? It's going to increase the number by
13:27:03one. But here you might be thinking okay
13:27:04this is a string. But what happens
13:27:07writing radius or normally the radius
13:27:09strings can also works work like
13:27:11counters. So I'm just going to write it.
13:27:13So radius
13:27:15strings can also work like counters. So
13:27:19now let's say if I wanted to do const
13:27:22after increment and I'll do a and I'll
13:27:25do radius and then you'll do in cr. So
13:27:29here what you have to pass. So you have
13:27:31to pass a string key, right? So this
13:27:34will be the key that you have to pass
13:27:35and then you'll just log it once again.
13:27:40Right? You'll save and run it again. So
13:27:43you can see that you're getting 101.
13:27:45Okay? So this is all about the strings.
13:27:48Now what will be that uh next step next
13:27:50will be h has. Now has is going to do
13:27:52what right? So let's understand here
13:27:54only.
13:27:55So has is going to so I'm just going to
13:27:58take this one as all right. So now let's
13:28:00understand h has right. So what actually
13:28:01radius has is so radius has is going to
13:28:04stores many uh many small fields under
13:28:07one key. So it's going to stores
13:28:10many small uh fields under one key. Now
13:28:15what will be a good example for this? So
13:28:18one good example for this will be uh so
13:28:21let's [snorts] say we have a small
13:28:22object right so this will be a good
13:28:24example or something like map inside
13:28:28radius so this will be your has right so
13:28:32now let's say uh there can be any key
13:28:35right so there is an any key so this is
13:28:38your key name and then you're going to
13:28:40have some fields here for that
13:28:42particular key so now let's say you have
13:28:44a uh field which is name and the name is
13:28:49Sam something like this and you also can
13:28:52be having a email and this is your email
13:28:56something like this so let's understand
13:28:58this one with example so what I'll do
13:29:00right so let's do this one as const and
13:29:03I'll do has key and what we can do maybe
13:29:06let's do demo colon user colon profile
13:29:11okay so now what we can do simply so I'm
13:29:14just going to do a And here we have a
13:29:16radius and we need to understand one
13:29:18method and that is called h set. So what
13:29:21this is going to do this is going to
13:29:23store the many fields that we wanted to
13:29:25have under this particular key. It's
13:29:27going to store that. Okay. So it's like
13:29:29a has like a small object inside radius.
13:29:33So this is the method we need to do how
13:29:36the structure will be. So here you have
13:29:38to pass the key. So this will be your
13:29:41key and then you can pass the property.
13:29:43So let's say I'm going to take a name
13:29:46and this will be I think this is wrong.
13:29:48This will be capital right? So here uh
13:29:51this will be key and then we have to
13:29:52take the property. So now let's say I'm
13:29:54just going to take this one as sum and
13:29:56I'm also going to take a city and let's
13:29:59do something like US. Okay. And then
13:30:01what you can do right uh so here uh
13:30:04let's say I wanted to get this value
13:30:07now. Okay. So this is how we are going
13:30:09to set some certain fields inside a uh
13:30:13inside a key using h has concept right.
13:30:15So we are using h set. Now to get this
13:30:19I'm just going to do extract profile
13:30:21info whatever you wanted to give here.
13:30:24So this will be equal to have it. So do
13:30:27radius and you're going to use h get
13:30:30all. So this is what you have to use.
13:30:33And here also you have to pass the key.
13:30:35So I'm just going to pass this one as
13:30:36has key. Now let's go here and then I'm
13:30:39just going to copy this
13:30:41and I'll paste it here and let's see
13:30:44what you're getting right. So I'll just
13:30:46run this one second. So I'm getting name
13:30:48and city. Okay. So this is how you're
13:30:50going to make use of uh has. Now all
13:30:54they might be thinking okay these are
13:30:56very uh simple concept but these simple
13:30:58concepts are actually important. Why?
13:31:00Because when you are going to learn all
13:31:02of these and then you're going to let's
13:31:03say you're creating a practical project
13:31:05there you have to understand whether you
13:31:07actually can apply all these concept
13:31:09inside your real project you're getting.
13:31:11So let's say you have a particular
13:31:13endpoint and you wanted to use radius in
13:31:16that. Now the requirement is such a way
13:31:18that you have to use string concept and
13:31:21has concept both. So this is the
13:31:23knowledge that you have to acquire that
13:31:26okay in that particular scenario you
13:31:28will be able to understand that okay
13:31:29which are properties I need to apply or
13:31:32what are the concepts so what I mean by
13:31:34it's not like we are blindly doing all
13:31:35of these at the end when we going to do
13:31:38practical you'll see that some of the
13:31:39things that we are doing here we will be
13:31:41applying in a real project and that will
13:31:43be your final outcome okay uh next uh
13:31:47what else we have okay let's understand
13:31:49list
13:31:51so list will be so I'm just going to do
13:31:55list
13:31:56so radius list will be ordered okay so
13:32:01this will be ordered collection of
13:32:04values okay so again here also you're
13:32:07going to have a key and then there will
13:32:08be some values okay so this is the
13:32:10simplest example that these will be some
13:32:12collections of values but it will be
13:32:14ordered so now let's see one simple
13:32:17example [snorts] so I'll just do here
13:32:19const I will do list
13:32:22key and here I'm just going to do maybe
13:32:24demo let's say I'm just going to take
13:32:26some messages in order and here what I
13:32:29will do simply first I'm just going to
13:32:30have it so I'll do list key and you're
13:32:33going to do l push
13:32:37no not loose man so here we are going to
13:32:40use a radius
13:32:43loose
13:32:45okay so this is what you're going to use
13:32:47you have to pass a key which will be
13:32:48list key and let's say I wanted to give
13:32:51uh Hello.
13:32:54Okay. And again, let's I wanted to add
13:32:56some more. So maybe I I'll do hi radius.
13:33:00All right. So now let's say we wanted to
13:33:01extract. So what I'll do, right, I'm
13:33:03just going to do extract
13:33:05messages and this will be avid and here
13:33:08we're going to have radius dot we have
13:33:11to use something called l range. Here
13:33:13we're going to pass the list key and
13:33:15then we're going to give the start and
13:33:17the stop. And now let's log this. Right?
13:33:20So I'm just going to do extract
13:33:22messages. Save this. And now let's
13:33:26clear. And then I'm just going to run it
13:33:28again.
13:33:30Okay. So you can see that first you're
13:33:31getting high radius and then hello. This
13:33:33is why because we using l push. Okay.
13:33:36Now if you're getting confused, let me
13:33:39just quickly show you that diff between
13:33:42lus
13:33:44and rpus.
13:33:48So you can see that now L pus is going
13:33:50to do what? It's going to insert the X
13:33:53at the left side. Okay. R push is going
13:33:56to insert this one on the right side. So
13:33:59now if I'm first adding this one, so
13:34:01this will be added. When I'm going to
13:34:02add high radius, it will be added on the
13:34:04left side. So that's why you're getting
13:34:06this. You're getting this one. And that
13:34:08is the reason you're getting hello on
13:34:10the at the end. Okay? Because we using
13:34:13loose. If you want to get in the reverse
13:34:16order, what you have to use? you to use
13:34:18arpus. Okay. So I'm just going to give
13:34:19this one as a homework to all of you. So
13:34:22this is about the uh list. Next uh what
13:34:26we have I think we also have to discuss
13:34:28about. So let's uh discuss about set. So
13:34:31now I'm just going to do this one as
13:34:32set. So what actually set? So set will
13:34:35be or okay let me just quickly write it
13:34:37here. It will be easy. So loose right.
13:34:39So loose will be adds a new item at
13:34:44beginning.
13:34:47Then you're going to have l range. L
13:34:49range is going to do what? It's going to
13:34:51reads item items from the list. Simple.
13:34:56And then we going to have uh we also
13:34:58going to have what? L arpus. So we also
13:35:02have the arpus. Arpus is going to will
13:35:04be what adds the item
13:35:07at end. Okay, we also have something
13:35:10called L stream, right? These all are
13:35:13very important one. So it's going to do
13:35:15what? It's going to keep
13:35:17only part of the list. You can also
13:35:21verify. So if you go here and let's do L
13:35:24trim.
13:35:26So L trim is a command to trim an
13:35:29existing list. So it contain only the
13:35:31specific range of elements. Okay. So you
13:35:33have to give the key the start and the
13:35:35stop. So this is about the list. So now
13:35:40let's move to the set. So what will be
13:35:41set? Set is like if you have have some
13:35:44idea on JavaScript sets how it usually
13:35:46works. So set is usually stores unique
13:35:49values only. Okay. So it is going to
13:35:51sets unique unique
13:35:54sets of values only. Okay. So now uh
13:35:59what will happen? Uh this can be
13:36:01interview question but this will be very
13:36:02beginner level of questions. What will
13:36:04happen if I try to add same element
13:36:06multiple times? So it's going to ignore
13:36:08the one that you have already added.
13:36:11Very very simple concept. So how it will
13:36:14work? So let's go here and then I'm just
13:36:15going to do con. Let's do a set key. And
13:36:18I'm just going to let's say I have some
13:36:20tags and I wanted to get the tags only.
13:36:23And here I'm just simply going to add
13:36:24it. And you're going to do radius. And
13:36:26now this will be not loose. This will be
13:36:29add. So s add is going to add and it's
13:36:33going to create a set and it's going to
13:36:36add that unique value. So what I mean by
13:36:38unique value here. So now let's first of
13:36:40all I'm going to give set key and I'm
13:36:41adding here node JS. And now I'll just
13:36:45uh let's paste it. Let's do next JS and
13:36:49I'm just going to do uh next JS again.
13:36:52Okay. So there is a duplicate. Okay. So
13:36:54what will happen here? So first of all
13:36:56let's say I wanted to get or I wanted to
13:37:00uh return how many unique members exist
13:37:03in this particular set. So how I can do
13:37:06that? So first of all let's say I wanted
13:37:07to get the tag count and this will be a
13:37:10we have to use something called s card.
13:37:13Okay. And here we're going to pass a set
13:37:15key. Now let's see what is happening.
13:37:17Right. So I'm just going to log this.
13:37:23So do tag count save.
13:37:30Now you can see that you're getting only
13:37:31two. Why? Because even though you've
13:37:34added n just two times, it is going to
13:37:36consider the nes unique. Okay. The first
13:37:39one. Next one it's going to ignore.
13:37:41Okay. Then we have something called
13:37:43sorted set also. Okay. So let's say uh
13:37:46I'm just going to do con rank key
13:37:49something like this. Rank key. And then
13:37:52I'm I'll do demo and let's I just going
13:37:54to take some kind of leader board and
13:37:57I'll do a radius dot we have something
13:38:01called Z add. Okay. So what J uh Z add
13:38:05is going to do is going to store your
13:38:07member plus scores. When you have some
13:38:10kind of uh condition or feature that you
13:38:13have to implement where you need to
13:38:15actually get the data based on ranking
13:38:17it's very very very important concept.
13:38:20Okay. So now what we going to do? We'll
13:38:22lose Z at. So you have to pass the key.
13:38:24So we'll do rank key and I'm just going
13:38:26to give a score here. See score will be
13:38:29100. Okay. And you have to give a value
13:38:32here also. So now let's say this is a
13:38:34player A. Now I'm going to copy this and
13:38:37paste it here. So this will be score uh
13:38:41200 and this will be my player B. So now
13:38:44what we going to do right? So let's say
13:38:46uh I wanted to do something. I want to
13:38:49increase this particular score that I
13:38:52have by a particular amount. So to do
13:38:55this one, we have something called Z
13:38:57increment by that I'm talking about full
13:38:59form but in short we have to do
13:39:01something like this. So let's say I
13:39:02wanted to get the new score. So first I
13:39:06will do a so this will be Z. Sorry again
13:39:09I'm doing Z. So this will be radius dot
13:39:12Z increment by
13:39:17you have to pass the key here and let's
13:39:19say you have to pass the increment
13:39:20number. So let's say by 50 and also you
13:39:22have to pass the member. What will be
13:39:24your member? Member will be your player
13:39:25A. Okay. So here you have to give this
13:39:28one as player A.
13:39:31So now let's log this. So this will be
13:39:35the new score. So now let's save this
13:39:40and if I run it again. So what we'll be
13:39:43getting? We'll be getting 150. Very very
13:39:45simple. So we are just increasing this
13:39:47one by 50. Now if you wanted to get the
13:39:50rank from highest score to lowest score
13:39:54there you have to use something called Z
13:39:56rev rank. So I'll do con rank
13:40:03and this will be a radius dot z uh we
13:40:08have the rev rank okay so here you have
13:40:12to pass the rank key and let's say what
13:40:15I wanted to do I wanted to pass the
13:40:17player B
13:40:20okay and here let's I'm just going to do
13:40:22a log and maybe I'll do a rank here so
13:40:27if I Save this.
13:40:31So you can see that you're getting zero.
13:40:33Okay. Now why we are getting zero? The
13:40:36reason is because zero will be always
13:40:38considered as top rank. Okay. So what
13:40:41this is going to do? This is going to
13:40:43give the rank from highest score to the
13:40:45lowest score. So now I think this is
13:40:48done. If you are getting confused, let
13:40:49me just uh give you one example. Right?
13:40:52So I'm just going to copy this and I'll
13:40:54just do here. Okay. Tell me why the last
13:40:57rank
13:40:59console is giving zero. Okay. So let's
13:41:03see
13:41:05now see it's printing zero because
13:41:07calculate zero to index rank order from
13:41:09highest score to lowest score. So this
13:41:11is I was talking about. Now this might
13:41:12be little confusing because when uh I
13:41:16I remember I learned for the first time
13:41:18right I was like oh my okay what is
13:41:20happening here. So this is the reason I
13:41:22mentioned. So if you see okay first of
13:41:24all see this is going to add this one so
13:41:26it's going to get first time when I'm
13:41:28going to do Z add it's going to get C
13:41:30score of 100 player B is going to get a
13:41:32score of 200 fine I added 50 okay so
13:41:35it's become 150 right so player A is
13:41:37become 150 so now the final reader will
13:41:40be what 200 150 so what Z rank is going
13:41:44to do I already mean it's going to give
13:41:46you the rank from highest score the
13:41:48lowest score so who is the lowest sorry
13:41:50highest score here still player Correct.
13:41:53So that is the reason you are getting
13:41:54this. So now it's going to do what? It's
13:41:56going to sort the leaderboard in the
13:41:57descending order. So highest order is
13:41:59going to get the top uh position. So now
13:42:02I what I mentioned here that zero will
13:42:04be equal to always what? Highest score.
13:42:06Okay. Or top rank. Zero will be
13:42:10I'm just going to do like this. So this
13:42:12is how I don't I remember this one. So
13:42:14zero will be considered as top rank.
13:42:16Right? So now this will be your uh rank
13:42:19zero, first place highest score, player
13:42:21B and rank one because we are passing
13:42:24player B has the absolute highest score.
13:42:27So their reverse rank is exactly zero.
13:42:30So when you're passing player B, so
13:42:31you're getting this one as zero. What
13:42:33will happen if I pass this one as player
13:42:34A? I think you can actually guess it. So
13:42:37it will become one because this will be
13:42:38the second player. Okay, because B is
13:42:41first here. Now I'll give you one
13:42:43homework because we're adding by 50
13:42:45right here. players could do this. Uh
13:42:48you can just add one more time, right?
13:42:50Let's say you added 100 or 200. Now see
13:42:53that the moment player will be increase
13:42:56by player player B. So now let's say
13:42:58player A score is 300. You'll see that
13:43:00when you're going to uh console the
13:43:03rank, player A will become the highest
13:43:05rank and then the player B something
13:43:06like that. Okay. So this is about the uh
13:43:09uh how you can work with sorted set.
13:43:12Okay. Very important concept. uh what
13:43:14else we have? I think we have already
13:43:17complete most of the things. So the last
13:43:19I think we have to also understand some
13:43:20of the very basic concept of TTL. Okay.
13:43:24So first uh what I will do right? So
13:43:26let's understand very basic concept here
13:43:28what actually TTL means. So TTL will be
13:43:31as much I can recolct it will be time to
13:43:35leave. Okay. Or you can also consider
13:43:38this one as expiry. Right. So this is
13:43:40expiry. So we can just verify. So TTL
13:43:43means
13:43:44time to leave, right?
13:43:51Okay. Okay. So let's take one. So this
13:43:54will be TTL or XY. So what this uh is
13:43:58going to be? Sorry, why this is going to
13:44:00be helpful? What this is going to tell
13:44:02radius? So it is uh it's going to tells
13:44:05radius that how long Okay, you can note
13:44:07it down. how long a particular key
13:44:09should exist before it's going to
13:44:12deleted automatically. This is a very
13:44:13important concept. Okay. So, it's going
13:44:15to tell it tells radius that how long a
13:44:20key how long a key should exist
13:44:24before being deleted automatically.
13:44:31Okay, you're getting so now [snorts]
13:44:33maybe let's say I have a key here,
13:44:35right? So I have a key of a and then
13:44:37this key has a value of something maybe
13:44:40any value you can take and I'm giving a
13:44:42ttl of 300 seconds. So what will happen
13:44:46that means after 5 minutes radius is
13:44:49going to radius is going to delete this
13:44:54key automatically.
13:44:57Okay, I hope this is clear. So now let's
13:45:00understand maybe uh we'll just do like
13:45:03this, right? So I'm just going to do
13:45:04cons. Let's take a OTP key or whatever
13:45:07key you wanted to take. So I'll do demo
13:45:09OTP. And here I'm simply going to do a
13:45:12I'll do radius. And you can use simply
13:45:14set.
13:45:16And you're going to pass the OTP key.
13:45:18And I'll just do here 1 2 3 4 5 6. We're
13:45:21just setting the value here. Okay. Now
13:45:24I'm going to add a expired date here. So
13:45:26how you can do? So do radius dot expire.
13:45:30And you have to pass a key here. OTB
13:45:32key. And this will become 60. Okay. So
13:45:36once this TTL will end, radius is going
13:45:38to delete this automatically. So here
13:45:40what will be the expired time? The
13:45:42expired time will be 60 seconds. Okay.
13:45:45Because we are using 60. Okay. Now what
13:45:48you can do right? We can use TTL. So
13:45:50what TTL is going to do? TTL is going to
13:45:52show you the remaining seconds before
13:45:54it's going to expire. You're getting
13:45:56time to what I mentioned time to leave.
13:45:59Right?
13:46:00So now if I simply do con what will be
13:46:03the TTL
13:46:05so I'll do a radius TTL
13:46:09and you'll simply pass OTP key and then
13:46:12you'll just do console
13:46:14dot log and I can log this DTL okay so
13:46:18now if I go here and let's say I wanted
13:46:20to run this so it will be showing as 60
13:46:23because now we just started so once this
13:46:25detail is going to end radius is going
13:46:28to delete this particular automatically.
13:46:30Okay. So I think this is done. Now one
13:46:33last thing we have to understand that's
13:46:34I kept this one intentionally and that
13:46:37is how we are going to close the radius
13:46:38connection because you notice that it's
13:46:40actually not closing and to close the
13:46:42radius connection it is very very
13:46:44simple. I just have to do a and I'll do
13:46:46radius dotquit. Okay. And this is done.
13:46:49So now the moment I'll save this and
13:46:51you'll see that now if I going to run
13:46:52this it's closing. So that is the reason
13:46:54I kept that part intentional so that you
13:46:57can understand. Okay. So now this is how
13:46:59you are going to quit or how you're
13:47:02going to close your radius connection.
13:47:04So with this I think we have covered
13:47:06most of the things. These things are
13:47:07very very important. So now what will be
13:47:09the next step? Next step will be now we
13:47:10need to start working on our actual
13:47:12project. So now we're going to set up
13:47:14our radius and after that we'll move to
13:47:16the next section. All right. So moving
13:47:18to the next one. So now we have some
13:47:19basic understanding of the data types
13:47:21and how you can run and see the output
13:47:24and everything. Right. So what will be
13:47:26the next step? Now remember there are
13:47:27some more examples that we need to
13:47:29understand. Okay. But this time what we
13:47:31going to do right because now we already
13:47:33have some very basic idea. So some of
13:47:35the practical things now we are going to
13:47:37apply in our project. Okay. So this is
13:47:39how we are going to understand all the
13:47:41things. So what we have to do? So first
13:47:43thing we will start with creating the
13:47:45radius connection in our project. Now
13:47:47remember this is now not example one.
13:47:50This is actually how we are going to
13:47:52apply in a project. Okay. So first what
13:47:54we need to do? So first we need to see
13:47:55that some of the things whether we have
13:47:57completed or not. So what will be the
13:47:58first thing? First thing we need to see
13:48:00in your project. Now why I'm explaining
13:48:02all of this? Now forget about this
13:48:03example folder. This example folder is
13:48:05the dummy code snippet kind of thing
13:48:07that will give you the basic idea. Now
13:48:10when you implement in a project so first
13:48:12thing you have to understand that okay
13:48:13whether the radius is installed or not.
13:48:15So yes we have already installed radius
13:48:17right. So we have the radius package
13:48:19here. Second because we using docker we
13:48:22have the docker uh service is running or
13:48:24not. Yes docker service sorry not yeah
13:48:26docker radius service is running correct
13:48:29also we have the radius volumes or
13:48:30radius data. So first thing we need to
13:48:33do what? So first we need to create our
13:48:35actual radius connection for this
13:48:36particular project. Second we are going
13:48:38to use that connection where in our main
13:48:40serverts file. So these two things we
13:48:43are going to do. So first maybe what we
13:48:46can do right. So uh let's create one
13:48:48radius folder here.
13:48:51Inside this let's create a client ds.
13:48:55Okay. So now first of all what we going
13:48:57to do now you see that once you
13:48:59understand some of the concepts how much
13:49:00easier it will be for you to know. So
13:49:02first of all you need to get something.
13:49:05So what I need to get I need to get the
13:49:07create client. This is what we have
13:49:08learned right in the previous section.
13:49:11So first I'm just going to do con radius
13:49:14url. So this will be process env dot.
13:49:19So rad or so we are going to use that
13:49:23whatever we have here. So copy this and
13:49:26then paste it here. So now I'm just
13:49:28going to do so we need to create a
13:49:30radius client. Correct. So I'm just
13:49:32going to do export cons. Why we need to
13:49:33do export? Because we can or we need to
13:49:36use this radius client in our other
13:49:38places. So I'm just going to do radius
13:49:40client and this will be equal to create
13:49:43client. And here we are going to pass
13:49:45the URL and this will be your radius
13:49:48URL. Sorry not radius URL we have to
13:49:51use. Now what we need to do we need to
13:49:54fire some of the events. So what are the
13:49:56things we need to fire? So first I
13:49:58wanted to see that uh whether the
13:50:00connection or the TCP connection is
13:50:02established or not. Okay. So how we can
13:50:04do that? So we have radiusclient do on
13:50:07and here we have a method called
13:50:08connect. Now this is going to fire when
13:50:13the TCP connection to radius is
13:50:15established. Okay. And here what we can
13:50:18do we don't have to do anything else in
13:50:19the call back. We can just log the
13:50:22error. So what you can do right you'll
13:50:23just do radius client
13:50:26connected something like this. So this
13:50:28is the first one. Then we need to see so
13:50:32this is only the connect. Okay. One we
13:50:34need to take for ready. So when the
13:50:36connection is ready. So here I'm just
13:50:37going to do this one as ready. So this
13:50:40will be radius client ready. Okay. Also
13:50:43we can take one more which will be
13:50:45error. So if there are any kind of
13:50:46error. So I'm just going to do this one
13:50:48as error. And this will be radius client
13:50:51error because this is a call back. You
13:50:53can take a error here. And that error
13:50:54you can just log here. Okay. That's it.
13:50:58And then we are going to take last one
13:51:00which will be end. So this will be end.
13:51:03And this will be when the connection
13:51:05will be closed. We don't need this one.
13:51:06We can remove this. and we'll do radits
13:51:09client connection closed. So this is
13:51:12done. So now what are we going to do
13:51:14right? So first of all I'm just going to
13:51:16create one more function here. So I'll
13:51:18just do export async function and I'll
13:51:22just do connect radius.
13:51:26So what will be the return? So this will
13:51:28be promise and then we just have to take
13:51:30a hide here. So for this one, first of
13:51:33all, I'm just going to check if the
13:51:35radius client that we have is open. If
13:51:38this is false, so why? So what we need
13:51:40to do here? So we are going to only
13:51:42connect if the client is not already
13:51:44open. You're getting so this is what
13:51:46you're checking. If the client is
13:51:47already open, we don't have to do
13:51:48anything. So this is not so in that case
13:51:51we have our radius client and here you
13:51:53have to do connect. Okay. So here now
13:51:55only wanted to call connect. So this is
13:51:57the first thing and then ping pong that
13:51:59concept right ping means we are going to
13:52:02give ping and we need to see whether we
13:52:04are getting the ping response or not as
13:52:06pong. So I'm just going to do here con
13:52:09uh let's do pong and I'll do a
13:52:12radiusclient dotping
13:52:15and here I'm just going to do so let's
13:52:18do this one maybe uh let's log it only I
13:52:22think that is fine so I'll just do here
13:52:25radius
13:52:27ping response and this will be and I
13:52:31think this is done and then I'm also
13:52:33going to take one more here so I'll do
13:52:34export as sync function and I'll Just do
13:52:37this one as uh disconnect
13:52:40radius. So this will be again promise
13:52:45void and here we are going to check. Now
13:52:48what you have to check if the uh
13:52:50connection is already open then you're
13:52:51going to close it. You're getting if the
13:52:53connection is not open how we are going
13:52:55to close it. So to check if the radius
13:52:57client dot is open that means if it is
13:53:00already open then how I'm going to close
13:53:03it. Now see this concept we have learned
13:53:04just now. So this is what I'm talking
13:53:06about repeating every time not only this
13:53:09video in all the videos in last 2 three
13:53:11years whatever videos I'm doing right.
13:53:13So what I mean by this whenever you
13:53:15learn learn any concept you have to see
13:53:17whether you are able to apply that
13:53:19concept practically in a project or not.
13:53:21If you're not able to do it that means
13:53:22there is no point of learning that
13:53:24concept you're getting. So let's say
13:53:25you're learning a nodejs concept called
13:53:28file system and you're building a real
13:53:31practical project and you have to see
13:53:32whether those file system concepts you
13:53:34can apply in that project or not. Okay,
13:53:37no one in in any project you are not
13:53:39going to get like this. Okay, there will
13:53:40be some simple thing and then you're
13:53:42just going to apply file system read
13:53:44this method there will be situational uh
13:53:46concept right so in that particular
13:53:48situation you have to understand whether
13:53:49you can apply that concept or not so
13:53:52here if it is opened so I need to close
13:53:54this so how I'm going to close it so we
13:53:56have to call that quit method that we
13:53:58have learned right so this is going to
13:54:00close that connection so I think this is
13:54:02done right so this is clear now what
13:54:04will be the next step next will be now
13:54:06this is not yet completed because in the
13:54:08serverts we need to use this. So now
13:54:11here you can see that we are calling the
13:54:13test connection. So first of all I need
13:54:14to connect to my radius. Okay. So I'm
13:54:17just going to do a and I'll do connect
13:54:20radius. So we need to check here on the
13:54:22startup and also let's do one more thing
13:54:26here. I'm just going to do process dot
13:54:28on and what we need to do right see when
13:54:31we going to stop the server we have to
13:54:34close the credit connection also. So how
13:54:36we can do that right? we have the sign
13:54:40uh sign s it okay and here I'm just
13:54:43going to take async and then I'm simply
13:54:46going to do a and we have the disconnect
13:54:49radius and then you have to exit so we
13:54:51do process doexit
13:54:55no process doexit of zero and I think
13:54:58this is done so this what we need to do
13:55:00so now if I go here I think it's already
13:55:03running so you can see it's already
13:55:05connected which is fantastic but still
13:55:07I'm just going to run once again and if
13:55:09you run here you see the postgress is
13:55:10connected successfully ready is client
13:55:12connected ready and then you're getting
13:55:14the response also and uh this is the
13:55:17pong response that you're getting right
13:55:19so and the server is running so that
13:55:20means now we successfully
13:55:23uh initiated the radius connection and
13:55:26also we are able to we will be able to
13:55:29disconnect the radius also whenever
13:55:30you'll be stopping the server okay so
13:55:33this this is one small section that we
13:55:35have to do now again what going to do
13:55:37right let's move back to our examples
13:55:40we'll understand some more concepts then
13:55:41we'll again come back and then we are
13:55:42going to apply those concepts in this
13:55:44wheel all right so now let's move on to
13:55:46the next one which will be so we need to
13:55:47understand some of the more concepts
13:55:49okay so first so let's understand that
13:55:53what actually casting is right so
13:55:55because this is one of the main core
13:55:57concept that we need to understand and
13:55:59also you're going to understand what is
13:56:00radius caching that I mentioned and also
13:56:02invalidation both seeing means uh like
13:56:06If I wanted to explain a very simpler
13:56:08way. So let's say you are storing some
13:56:11uh data. I will not say data but storing
13:56:13the copy of data. Okay. In a fast place
13:56:16so that whenever you're going to do
13:56:18future request it can read that
13:56:21particular data from that place very
13:56:23quickly. Okay. So this will be very
13:56:24simple uh human like definition not like
13:56:27you are checking from charge but but uh
13:56:30this is what I will explain. Okay. So
13:56:31the casting will be it is like storing
13:56:34but the difference is see storing the
13:56:36copy of data storing the copy of data uh
13:56:40in a first place. So this can be any
13:56:42place. Now in this case we are using
13:56:44radius. So it will be in memory. So that
13:56:47uh so it will be stored in a first
13:56:48place. So future request
13:56:53can be can be read very quickly. So this
13:56:57will be a very basic definition and
13:56:59proper definition of caching right. So
13:57:01instead of fing the same data again and
13:57:03again uh we are actually reading the
13:57:06data from a cast. Now I already
13:57:09mentioned right that why we using radius
13:57:11because radius is in memory. So reads
13:57:13will be very very fast right it should
13:57:15be very very very fast extremely fast
13:57:18right now some of the reason that why we
13:57:22need to use casting. Now this is there
13:57:23can be so many reasons okay but I'm
13:57:26going to give you some of the very uh
13:57:27simple ones. So for example let's say
13:57:29you want to reduce your database load.
13:57:32This is one of the reason want to
13:57:34improve the response time. I think this
13:57:36will automatically come because uh the
13:57:38uh radius is very fast right so it's
13:57:40definitely going to improve your
13:57:41response time and also it's going to
13:57:44handle the repetitive reads properly or
13:57:48efficiently. Now there are some patterns
13:57:50that you have to understand. So we have
13:57:52something called cast aside pattern. So
13:57:55how this will work right in a simpler
13:57:56way. So first it is going to check the
13:57:59cast. So let's see if you have something
13:58:01cash if this is stored or not. Two. So
13:58:04this will be I'll do one
13:58:08here
13:58:10and then in the two this will be if the
13:58:13cast has already data. So it's going to
13:58:16return it if not if the cast doesn't
13:58:19have data.
13:58:22If the C doesn't have data so what I'll
13:58:26do it's going to read from your read
13:58:28from main DV okay and then once you read
13:58:32it then [clears throat] you're going to
13:58:33save it save in cash so what will happen
13:58:37from the next time it's going to read
13:58:38from the cache because that time cast
13:58:40will be having the data okay so this
13:58:43will be a cast aside pattern there is
13:58:46another concept called cash heat so what
13:58:49what is cast Right? So C hit will happen
13:58:53whatever data that you were requesting.
13:58:54So the requested data is already in C.
13:58:57Correct? So now consider you have
13:58:59something called a products endpoint,
13:59:01right? And here what will happen right?
13:59:04So let's say radius already has
13:59:06something called products colon all. So
13:59:10that means these products data is
13:59:12already present in this particular key.
13:59:14So what will happen? It's going to
13:59:15return the cache data immediately. So
13:59:18return the cash data immediately. Now
13:59:22one thing uh so let's understand here.
13:59:24So I'll do what is cast
13:59:27aside and cash hit.
13:59:33So see the C the application looks for
13:59:36data finds it and return it instantly.
13:59:39Right? Uh this is the optimal path
13:59:41because it bypasses the slow main
13:59:43databases entirely. Correct? Then you
13:59:45have cash miss also something cash asset
13:59:48pattern. So this is called lazy loading.
13:59:50So you can check it or I'll just read it
13:59:53properly that in this pattern the
13:59:54application logic directly manages both
13:59:56the cache and the database. Correct? I
13:59:57already mentioned that if it is present
13:59:59you give me the data back right you have
14:00:01the client request data application
14:00:03right and then you have the cash hit so
14:00:05it's going to return the data. So you
14:00:07have a radius cast right? If there is a
14:00:08miss so it's going to take it from DB
14:00:10and then it's going to return the data.
14:00:12So this will be your cash aside pattern.
14:00:14Cash M will be nothing but when your
14:00:16cash doesn't have that particular data.
14:00:18Okay. So in this case let's say you're
14:00:20getting the list of products and this
14:00:22cash is not present. So what will
14:00:24happen? It needs to return the data
14:00:26right. So in that case it's going to get
14:00:28the data from your DB and then you have
14:00:30something called TTL. TTL I've already
14:00:32mentioned that that will be time to
14:00:33leave. Right? So it's going to tell that
14:00:35how long that C data should stay before
14:00:38we are going to delete it automatically.
14:00:40So these will be all the concepts. Now
14:00:42because we already know all this, right?
14:00:44Let's see how much easier it will be for
14:00:45us to understand these things
14:00:47practically. So what I'll do right so
14:00:49we'll go here and let's do this one as
14:00:52radius caching. We'll do all at once.
14:00:54Okay, all the concepts. So I'll do
14:00:56radius caching. Let's go to package.json
14:00:59and I'm just going to copy this so that
14:01:01we can run it
14:01:03and I'll do radius
14:01:06caching and this will be radius casting
14:01:10right casting.
14:01:13Okay. So let's go here. First of all,
14:01:15what I'll do? So we'll go to this.
14:01:20I'll close this. So let's go here. I'm
14:01:23going to copy till this part. Not going
14:01:26to write. Okay. So these five things we
14:01:28need. So we we are creating this. So now
14:01:31first of all, we need to have our cast
14:01:33key. So you should always have your cast
14:01:35key, right? Cash key is there. Something
14:01:37like C key there. So what is your cast
14:01:40key? So I'm just going to take this one
14:01:41as let's say cash key. So this will be
14:01:44your demo colon products. So this is
14:01:48where I want to store my list of
14:01:49products in my cash. Okay. Then you're
14:01:52going to have a cash DTL in seconds. So
14:01:58I'm just going to do second. So what
14:01:59this means? This means cash is going to
14:02:02expire after 60 seconds. cash
14:02:07will expire
14:02:09uh after 60
14:02:13seconds. This is also very important
14:02:15because you see you can't give your TTL
14:02:19log also you have to invalidate the
14:02:21cash. Why? So let's say you have 10
14:02:24products [snorts]
14:02:25and you're getting the data from cash.
14:02:27It's fine. Now let's say there is some
14:02:29update in the data or there is a new
14:02:31product added. So now your 10 products
14:02:34will become 11. So if your data is
14:02:37already present in the cash and it's
14:02:39getting returned from the cash, it
14:02:40always going to return you the 10 data,
14:02:42not the 11 data and also not the updated
14:02:44data. For example, let's say there is
14:02:46one product and the product price is
14:02:48changed from 100 to 500. So in that case
14:02:51it will always return you to 100. It's
14:02:53not going to return the updated data. So
14:02:55that is the reason you have concept of
14:02:56invalidation. So you are going to
14:02:58invalidate that cast so that it's going
14:03:00to return the updated data back. So here
14:03:03I'm just going to do con products
14:03:06and I'm just going to let's take
14:03:07something like this right. So I'll do
14:03:08keyboard and then mouse
14:03:14and laptop something like this. So this
14:03:18is my fake database data. Now what I'm
14:03:21going to do I'll just do async function
14:03:25run and here first we're going to
14:03:28connect I'm just doing little first
14:03:33and then what I will do also let's do
14:03:36this right so I'm just going to close it
14:03:38also
14:03:40at the end
14:03:42so now first of all I uh I'm doing some
14:03:46request okay so this is my first
14:03:50request request. So what will happen in
14:03:53the first request? Pause the video and
14:03:55try to understand. See in the first
14:03:56request you it will not be cash hit it
14:04:00will be cash miss. Why? Because in the
14:04:03first request this data is not present
14:04:06in your radius cache. Correct? So what
14:04:08will happen every time whenever there
14:04:10will be first request will be made it is
14:04:13going to get the data from your DB. It's
14:04:15very simple concept. So that means first
14:04:17time it will be cast miss. Second time
14:04:21once it is cach means it's going to get
14:04:22the data from your DB we are going to
14:04:25store the data in your radius. So next
14:04:26time it's going to read the data from
14:04:28your cache. So now let's I'm just going
14:04:30to do let cast
14:04:33and this will be my ait and then I'll do
14:04:35radius dot get
14:04:38and I'm just going to pass the cast key.
14:04:40So I'm just going I'm trying to get the
14:04:41data from my cast. So first time this
14:04:44data will not be present. Okay. So then
14:04:46I'm simply checking. Okay. Now see this
14:04:48is the cash aside pattern. Okay, this is
14:04:50the pattern that we have discussed. So
14:04:52this is the cash aside
14:04:55pattern. So I'm just going to do if cast
14:04:59data is present.
14:05:01So you're going to return me that data.
14:05:03Okay. So I'm just going to do a
14:05:05console.log
14:05:06and I'll do C hit.
14:05:10Okay. And then log this. And then you
14:05:13have to get the data also, right? So I'm
14:05:16just going to get the data which will be
14:05:17JSON dot par and you're going to get the
14:05:21data here cast if this data is not
14:05:24present. So what we have to do? We have
14:05:26to get the data still right. So in that
14:05:29case this will be cast miss.
14:05:33So this time it's going to read the data
14:05:34from DV read from main DV.
14:05:38So in that case first of all what we
14:05:40going to do? So I'm simply going to do
14:05:41con uh products.
14:05:44I'll do DB products. DB products. Now
14:05:47let's do one thing. Let's change this
14:05:49one to DB products. And I'm just simply
14:05:52going to do this one as products. So
14:05:54this will be simply my DB products that
14:05:56I have. And now I'm going to set this
14:05:58one in my C. So now set or save the
14:06:04products in radius C.
14:06:08So in that case I'm just going to do
14:06:10radius dot set
14:06:13ex. So what this is going to do right
14:06:15the set x is going to also save your
14:06:18ttl.
14:06:19Why we need this? So that whatever cash
14:06:22that you are saving it is going to it
14:06:24doesn't leave forever. Okay. So what I
14:06:27mean by this? So this say tax is going
14:06:29to do like this. So this is also going
14:06:32to save also saves
14:06:36detail so that your
14:06:40cash doesn't
14:06:44leave forever. Okay, you can also check
14:06:48it here, right? So I always we are
14:06:50checking like this and it is actually
14:06:51easier.
14:06:55Okay, so it sets a value that is fine
14:06:59string value to a key assign uh
14:07:01expression time TTL in seconds. Okay, so
14:07:04it's going to have one uh time here. So
14:07:07how we can do that? So we are simply
14:07:09going to do what? So first I have to
14:07:10give the key. So you can see that key
14:07:12seconds and the value. So this will be
14:07:14my cast key. This will be my cast DTL in
14:07:18seconds. So 60 seconds. And then I'm
14:07:20going to store the data. So this will be
14:07:22JSON stringify. Okay. And then what data
14:07:24you want to store in a C the products
14:07:27data. So now this will be stored in your
14:07:29C. All right. So now so first of all
14:07:31let's run this. Okay. So what I have
14:07:33done? So first we are checking that if
14:07:35if it is present. So give me the data or
14:07:38else we're going to render cash means
14:07:40and then we're going to read it from our
14:07:41DB and then we're going to set into C.
14:07:44So now first of all let's uh go here and
14:07:47[snorts] then I'm just going to copy
14:07:49this and I'll do npm run and let's see
14:07:54what we getting right. So first of all
14:07:55you see that we are getting cast miss.
14:07:57Okay. So why we are getting castm?
14:08:01That's because okay here we have to
14:08:03give. So it's coming here. Makes sense
14:08:05also if you log the data you'll be
14:08:06getting the data from here. But next
14:08:09time now we should be getting the data
14:08:10from my our cast. So now let's run it
14:08:13once again. And we are getting cash hit.
14:08:16Okay.
14:08:18And you can see that this is the data
14:08:19that you're getting. Okay. So that means
14:08:22next time this is already present. This
14:08:25is very very important. So first time
14:08:27what happened? So your data is not
14:08:29present in the cache. You're reading
14:08:31data from your DB and you're setting the
14:08:33data in your radius cache. Next time
14:08:36this will be uh data is already present
14:08:38in your C. So this will be cast hit. So
14:08:40you're going to get the data right?
14:08:42Every time you're going to run you're
14:08:43going to get from your cast only. Okay.
14:08:46See. All right. So now uh what I have to
14:08:49do right first of all let's understand
14:08:51another problem and that is called I
14:08:54will uh that will be like still cash
14:08:57problem. So what I mean by this? So now
14:09:00consider that I have my DB products and
14:09:03this has all these products correct. So
14:09:05we have these products. Copy this
14:09:09and here I'm just going to give one more
14:09:11which will be my desktop. So now what I
14:09:15need to do right so now I'm just going
14:09:16to do this one as where you're getting
14:09:19this one. Oh, I think I've used con,
14:09:21right? Maybe. Yes. So to use this one as
14:09:24late.
14:09:26Okay. So first what I'll do? So let's
14:09:28log this. So what I mean by this? So
14:09:32consider this right. So why I'm
14:09:35explaining because for some of you it
14:09:36will be difficult. So this is not like a
14:09:38dummy data right. This is actual
14:09:39operation that you are doing in your
14:09:41project. you're building some fullstack
14:09:43application and let's say you have a API
14:09:46or you're creating some product actual
14:09:47product and that data the new data this
14:09:50desktop is the new data is added in your
14:09:52DB correct so now what I'm going to do
14:09:54right so I'm just going to do a log and
14:09:57here I'm just going to do DB products
14:09:59okay save this and then I'm just going
14:10:01to run again so you can see that we are
14:10:03getting four right so cast me and then
14:10:05we getting keyboard mouse and all these
14:10:07thing so now uh what we need to do right
14:10:10and also if you See we are getting this
14:10:12log from here.
14:10:15Okay. So this is the log that we are
14:10:17getting. So now what I going to do
14:10:20right? So first of all I'm just going to
14:10:23uh do something like this maybe. So
14:10:25let's do here cast
14:10:29and I have it radius.get get and I'm
14:10:33just going to do this one as cast key
14:10:36and then I'm simply going to do log
14:10:39and here I'm just going to do here cast
14:10:43data and this will be JSON dot parts and
14:10:48then I'm just going to get the cast
14:10:52data. So let's save this and we'll see
14:10:55what is happening here. So we'll clear
14:10:57this.
14:10:59Okay. So what are you getting? You're
14:11:01still getting the old data. Now this is
14:11:04a huge problem. So this is called stale
14:11:06cache problem. So that means even though
14:11:08your DB actual DB has more products or
14:11:11newly added products or let's say there
14:11:13is a update maybe laptop uh spelling is
14:11:15changed from laptop to big laptop
14:11:18something like this still your cache
14:11:19data has the old data right and this
14:11:22makes sense right because you haven't
14:11:23invalidated or deleted your cash. So in
14:11:26that case what will happen even though
14:11:27you can have more data you are still
14:11:29going to get same cast data every single
14:11:32time. So this is a problem. So now to
14:11:34solve this we have a concept called cash
14:11:36invalidation. This is a extremely
14:11:38important concept. Okay. These are the
14:11:39concepts that you are going to use
14:11:41actually in your project. Okay. So we'll
14:11:43do C invalidation.
14:11:46So what this is going to do right. So
14:11:48this is going to so we are going to have
14:11:50some kind of mechanism in our code in
14:11:52our actual API that okay whenever I'm
14:11:54going to create a new product or
14:11:56whenever I'm going to update a new
14:11:57product or whenever I'm going to delete
14:11:59a product I need to do what I need to
14:12:01delete the old cash so I'm just going to
14:12:04give a sort that okay whenever I will do
14:12:06any so or let's put it in this way when
14:12:09DB changes very simple whenever your DB
14:12:11changes you're going to delete the cache
14:12:13this is the best way to understand now
14:12:16for beginners whenever DB changes is
14:12:18you're going to delete
14:12:20delete your old cach immediately right
14:12:24so you're going to so that you'll get
14:12:25the uh updated data here so how you're
14:12:28going to do that so I'm just going to
14:12:29have it radius dot delete
14:12:32and here we're going to pass the cast
14:12:33key and I'm just going to do a log
14:12:37and I'll do cast deleted
14:12:40and then spelling this wrong so now
14:12:44again I'm just going to check if not
14:12:46equal do cast.
14:12:49So I'm just going to do a log here. I'll
14:12:53do cast data
14:12:56after delete. And here what we going to
14:13:00do, right? So I'm just going to do con
14:13:02fresh
14:13:04products.
14:13:06So this will be again your DB products.
14:13:08But in actual scenario, this will be
14:13:09again your data from your DB. So this
14:13:12will be again your data from your DB
14:13:14after changes, right? After changes
14:13:18after data changes and then again I'm
14:13:20just going to set it. So I'll do radius
14:13:22dot set
14:13:24X and here I'm just going to do this one
14:13:27as C key I'll do C DTL in seconds and
14:13:32again you're going to do JSON dot
14:13:33stringify and you're going to pass the
14:13:35phrase products you're getting. So now
14:13:38again I'm just going to do a log here.
14:13:44Okay, after this I'm just going to do a
14:13:46log and I'm just going to do phrase data
14:13:50and this will be phrase products.
14:13:55So now if I save this so now notice what
14:13:57we are doing we doing a invalidation
14:13:59cash invalidation by deleting the old
14:14:01cash and then again we are setting here
14:14:03that if the cash is not present now
14:14:05again you give me the data from the DB
14:14:06and then again you're going to set it in
14:14:08your C. So let's run it again. So you
14:14:11can see that we are getting what
14:14:14cash data and cash deleted and then we
14:14:17are not getting this one. Okay, let's
14:14:18run it once again
14:14:21and you can see that what we are getting
14:14:23cash deleted.
14:14:26Something we are doing wrong here. If
14:14:28not oh okay we have to actually
14:14:32get the data man that's why. So first we
14:14:34have to get the cache data which will be
14:14:35have radius dot get and this will be
14:14:38cash key. then only you'll be getting
14:14:40that if this is present because we've
14:14:41already deleting it. So first we need to
14:14:43see if the cache is present. So first we
14:14:45need to get the data and this is not
14:14:47going to find because we've already
14:14:48deleted it. So then it's going to read
14:14:50it from the DB. So now I think this will
14:14:52work
14:14:55that was the mistake huh see so now
14:14:57let's go one by one. So first we have
14:14:59what? Cast deleted. So now we are
14:15:02getting what? So this is not going to
14:15:03give you any data. So that mean cash
14:15:05data after delete. So this is your
14:15:07phrase data. So this phrase data is
14:15:09nothing but your four data
14:15:11these four because this is the four data
14:15:13that we have added. Okay. So this is how
14:15:16you are going to use the concept of cash
14:15:18aside castl and invalidate cash and to
14:15:21solve this still cash problem. Okay.
14:15:23These are very important concept and
14:15:25most of the times you're going to use
14:15:26this.
14:15:28So with this now let's move to the next
14:15:30we going to uh apply some of the things
14:15:32in our actual project in the next
14:15:33section. All right. So now let's
14:15:34implement some of this concept in our
14:15:36project. Okay. So for that what you're
14:15:38going to do right if you go to services.
14:15:40So let's go to product service and let's
14:15:42close everything else. So first of all
14:15:44we'll see that what we are doing here.
14:15:46So first you can see that we have one
14:15:48method which is going to get all the
14:15:50products. Now here one thing I wanted to
14:15:51mention we are not focusing on filter.
14:15:54Okay for now and I will explain the I'll
14:15:56explain the reason why. So for now you
14:15:59just see that we are getting uh all
14:16:01products there is a method uh service.
14:16:03So we just creating one on query and at
14:16:05the end what simply we are doing we are
14:16:07simply getting the result from your DB
14:16:09and then we are returning that and if
14:16:11you go to your controllers in the
14:16:12controllers we are using that uh what is
14:16:15that get product so this is the method
14:16:17that we are using and if I go here right
14:16:19so let's go to products and if I send
14:16:21this so we getting the whatever products
14:16:23that we have added in the poss DB so now
14:16:26what we need to do right we need to
14:16:28implement a caching for this particular
14:16:30for all these methods that we have so
14:16:32first we have the get all products then
14:16:34we have get product by ID create product
14:16:36and update product all these methods so
14:16:39first let's start with uh taking our
14:16:41cast key now remember whatever concept
14:16:43that we have learned so far that
14:16:44whenever you're going to implement some
14:16:46kind of cash there has to be some key
14:16:48right so that key is going to hold that
14:16:50information or hold that cash
14:16:51information so here I'm just going to
14:16:53con let's give this one as products
14:16:57all cash key now we are only focusing on
14:17:00getting all products for now and I'm
14:17:02just going to give this one as products
14:17:04colon all. So [snorts] now what also
14:17:07okay let's take one more thing and that
14:17:08is the TTL. So I'm just going to do this
14:17:10one con and I'll do products
14:17:14cash and I'll do TTL seconds
14:17:18and this will be 60. Okay. So now what
14:17:22we are going to do first of all these
14:17:24get all products now we are going to
14:17:26change this one from this particular
14:17:28method to a different method. Why? Now
14:17:31first of all let's do one thing right?
14:17:33Uh maybe let's create one more method
14:17:36here. Uh we'll create [snorts] one more
14:17:38method like get all products here after
14:17:40this and I'll explain or else it will be
14:17:42little tricky to understand what we are
14:17:44doing. So first of all I'm just going to
14:17:45do async and I'll do function
14:17:49and here I'm just going to do this one
14:17:50as get all products. You're going to get
14:17:52error which is fine and then here also
14:17:55you're going to get the filters. Right?
14:17:56So we have all these filters. So we'll
14:17:58copy this filters
14:18:01and let's paste it here. And what will
14:18:04be the return type? So this is going to
14:18:07return a promise
14:18:10and this will will return the type of
14:18:13product.
14:18:15Okay.
14:18:16So now first of all what we need to do
14:18:18right. So first of all we need to see
14:18:21whenever I'm going to call this
14:18:23particular service whenever I'm going to
14:18:25hit that particular endpoint to get all
14:18:27the products I need to see that whether
14:18:28that product is present in our cash or
14:18:30not. So this is again come back to the
14:18:32same concept that we have learned so far
14:18:34that is the cash aside pattern. If the
14:18:36cash is present you're going to return
14:18:38the data from your cache immediately. If
14:18:40the cash is not present, you're going to
14:18:42get the actual data from your postgress
14:18:44DB and you're going to return. But there
14:18:46can be some exception. For example, the
14:18:48stale cache problem that we have
14:18:49discussed that let's say now I added a
14:18:51new product. Still we are going to get
14:18:53the whole product, right? That part I
14:18:54have discussed. So that we're going to
14:18:56see later. So for now what we going to
14:18:58do right first of all I'm simply going
14:19:00to check that con and I'll do has
14:19:03filters. I'm simply going to check that
14:19:05if filter is present. So for now we are
14:19:07not focusing on filters and I'll explain
14:19:08why. So I'm just going to give boolean
14:19:11and I'll do filters dot
14:19:13category this is present or we also have
14:19:16the filter dot search right so I'll do
14:19:18filter dot search if this is present
14:19:20that means there is a filter and I'm
14:19:22simply going to check that if this has
14:19:24filter is present so in that case I'm
14:19:26just going to do console.log log and I'm
14:19:28going to do cash bypass for now. I'll do
14:19:31C bypass and this will be filtered
14:19:38product list. Now why why we are doing
14:19:41this right? So see when we have filter
14:19:44right so every filter combination
14:19:46actually we need a different cascade and
14:19:48this is a very important thing. So every
14:19:51filter combination that we have need a
14:19:56separate cast key. Why that is? Now
14:19:59consider that you are doing a filter. In
14:20:01the first filter you are only passing
14:20:03the category. In the second filter you
14:20:05are passing the search. In the third
14:20:07filter you're passing both category and
14:20:09search. So in that case you can't
14:20:10implement this using only one key. So
14:20:12there has to be a combination. Okay. For
14:20:15example, so let's say we have our
14:20:17products right? So we need to do
14:20:19something like this. We'll do products
14:20:21colon all and then here you're going to
14:20:24do a search. So let's say I'm applying a
14:20:26search and the keyword is keyboard
14:20:28something like this. Okay. So and then
14:20:30maybe let's say you are doing a category
14:20:32also. Let's I'll do products colon all
14:20:34colon category. And then here I'm just
14:20:38going to do accessories something like
14:20:39this.
14:20:43Okay. So [snorts] that is the reason for
14:20:45now we are bypassing. But what we are
14:20:46going to do right so first we are going
14:20:48to change this particular method to
14:20:50fetch all
14:20:53products
14:20:54from database. Okay. So that means this
14:20:58method will never change because we need
14:21:01to have this right because we don't know
14:21:02whether we have the cash all the time.
14:21:04If the cache is not present it going to
14:21:06it's going to fet the data as usual from
14:21:08your database all the time. So that
14:21:10means if filter is present so we are
14:21:12going to simply return the fetch all
14:21:15products from DB and then we're going to
14:21:17pass the filters here. Okay. But now
14:21:20first of all here we have to implement
14:21:22the cast. So that means when the filter
14:21:24is not present let's say I'm just
14:21:26getting the list of products here. This
14:21:28is just for uh explanation in your real
14:21:30project. You also have to implement for
14:21:32this particular
14:21:34uh scenario also. So now what we going
14:21:36to do right? So first we need to check
14:21:39that before we are going to ask our
14:21:41postgress for our products we need to
14:21:43check radius first that whether that is
14:21:45present or not. If radius already has
14:21:47the product list we are not going to
14:21:50fetch the same product list from our DB.
14:21:52Okay, I'm repeating this thing because
14:21:54if you understand the core concept and
14:21:56even if you do only two three examples
14:21:58right most of the things you'll be able
14:22:00to do it I can 100% guarantee even
14:22:03though if let's say you're not your
14:22:04basics are not clear and you're uh doing
14:22:07some very complex project some
14:22:09microservices and blah blah but you'll
14:22:11see that you'll be getting some problem
14:22:13so basic has to be very very clear so
14:22:15that you can understand what you're
14:22:16doing so now here I wanted to uh check
14:22:20that okay if the radius cash is present
14:22:22You also have to remember radius
14:22:24actually is not the source of truth
14:22:25here. Okay. So this is a very important
14:22:27point and most of the uh like whoever is
14:22:30teaching I'm not sure if they're
14:22:31covering this or someone may be skipping
14:22:33this but this is actually very
14:22:34important. Why radius is not the source
14:22:38of truth here. Okay. What actually it is
14:22:43uh storing? Remember I already mentioned
14:22:45that radius actually is going to store a
14:22:47temporary copy of data. that data
14:22:50originally come from your posgress DB
14:22:52only. So what is your source of truth?
14:22:54The postgress DB right. So now in this
14:22:57case I'm just going to do con cast
14:23:01products
14:23:03and here I'm just going to do a and I'll
14:23:06do radius client dot get. So first I
14:23:08need to check if the this is present or
14:23:10not and I'll do product all cash. So I'm
14:23:13simply checking if that uh product is
14:23:16present
14:23:18uh in cash radius cash or not. if this
14:23:20is present. So I'm simply going to do if
14:23:22the cash products is present. So let's
14:23:25do
14:23:27log
14:23:29and I'm just going to do this on a cash
14:23:31hit
14:23:33and I'm just going to do products
14:23:35all okay and then what are you going to
14:23:39do right? So here we are simply going to
14:23:42return
14:23:43JSON dot parts and here I'm just going
14:23:47to do C products as so type will be
14:23:51product. So this is what we're going to
14:23:53return. Okay. So this is radius is
14:23:55actually returning your cash data as a
14:23:57string. Why you need JSON parse? Because
14:23:59it's going to convert the string back to
14:24:01your actual array. Right? This is normal
14:24:03concept. If this is not the case, if the
14:24:06cash product is not present, so that
14:24:08means what? There is a cash miss right.
14:24:11So we are going to do cash miss
14:24:14and here now we are going to first do
14:24:16what? Whenever there is a cast me you
14:24:19need to fetch the products from where?
14:24:20From your DV. So we simply going to do
14:24:23con products
14:24:25and this will be a fetch all products
14:24:29from DV and you're going to pass the
14:24:31filters right. So we have to pass the
14:24:33filters. So now here we are going to do
14:24:37what? We're going to set our set our
14:24:40actual products
14:24:44data in radius cast.
14:24:48So now I'm simply going to divide radius
14:24:50client dot set x. We have already
14:24:53discussed see how we are doing right. We
14:24:55have already understood all of these. So
14:24:57it will be easy. So we have cast key. We
14:24:59have the cast ttl in seconds. And then
14:25:01we're going to store the data. So do
14:25:02JSON.stringify and this will be the
14:25:04products. Now these products is the
14:25:06products that we are getting from our
14:25:07DB. And then we are simply going to do a
14:25:10log and I'm just going to do cash set
14:25:14products colon all and what you have to
14:25:18return you have to return the products
14:25:19here and this is done. Okay. So now I
14:25:23think this should work. I hope this is
14:25:26clear. Now at the end your product
14:25:28controller doesn't know what is
14:25:29happening in the business logic. Right?
14:25:30So here it's going to return the product
14:25:33as usual. What you're doing is simply
14:25:34doing the main logic here that if the C
14:25:37is present, return the data. If this is
14:25:39not present, you return the data from DB
14:25:41first. Set it in your C and from the
14:25:43next time you're going to get from your
14:25:45C only. So now let's save this. Let's
14:25:47see if this is running or not. I think
14:25:48it's running.
14:25:50So now I'm just going to run it here. So
14:25:52let's run it. So let's see what you're
14:25:54getting. We're getting cash miss and
14:25:56cash set. And now we're going to run
14:25:57once again. And you can see that what
14:25:59will happen. It's you can see that cash
14:26:01hit. So now it's getting from your cash.
14:26:03Okay, you see immediately you're getting
14:26:05right. So this is from your radius guys.
14:26:07This is fantastic. Now see how much
14:26:10cleaner it is to understand. So that is
14:26:12the reason I always mention and not I
14:26:14always mention but that is how I usually
14:26:16teach right in my YouTube videos. I
14:26:18don't go into too many complicated
14:26:20things because at the end if you working
14:26:22in a company right let's say you are in
14:26:23college or you you have less than 2
14:26:26years of experience you'll see that even
14:26:28the whatever work you are doing in your
14:26:30company let's say product or service at
14:26:32the end they're not doing so many
14:26:34complicated things they're doing the
14:26:36normal basic things only but the concept
14:26:38has to be very clear although there can
14:26:40be 1,000 line lines of code but at the
14:26:43end you you will see that they're doing
14:26:44this cash aside cash invalidation as set
14:26:48and fetging the data from C or your
14:26:50fetch the data from DB and then set it
14:26:52in C. Now this [snorts] is a very basic
14:26:54level. There are so many advanced things
14:26:56is also there in radius but this is how
14:26:58this has to be done. Now see that every
14:27:00time it's going to hit the C and it's
14:27:02going to get the data from your C right.
14:27:04So if you run it here it's going to get
14:27:06and sometime it's going to miss. Why?
14:27:08Okay, this is another see it's working.
14:27:10Why? Because we've given 60 seconds
14:27:12here. The TTL is 60 seconds, right? You
14:27:14remember this one. So after 60 seconds
14:27:16it's going to delete that or invalidate
14:27:18that cash. So that is the reason you're
14:27:19getting. But if I run once again you see
14:27:21that it's cast it. So that means this is
14:27:24working absolutely fine. So now what
14:27:26will be the next step? Next let's do one
14:27:28thing. Let's uh do some more important
14:27:30things here only in this particular file
14:27:32in the next part because we also have to
14:27:34see that when we are going to this cash
14:27:37data is present and let's added a new
14:27:38product this data should be updated.
14:27:41Right? you are getting the the problem
14:27:43that I discussed the stale cash problem.
14:27:45So let's how we are going to do that in
14:27:47the next part. All right. So moving to
14:27:48the next one. So get all products we
14:27:50have done. So now let's do this one. Get
14:27:52product by ID. So what I uh what you
14:27:55mean by this right. So let's say
14:27:56whenever we are going to fetch a single
14:27:58product by ID. So here uh what you're
14:28:01going to do right? So also I will
14:28:04suggest right this one try to implement
14:28:06using the same concept. So what I mean
14:28:08by this this will be exactly same
14:28:09concept where we have discussed about
14:28:10the cast asset pattern right. So first
14:28:12we are going to see so let's see I'm
14:28:14hitting this particular endpoint from my
14:28:16UI side. So I need to check that if this
14:28:19particular product information let's say
14:28:21I have a product ID of product 10. So ID
14:28:24is 10. So if that 10 product is
14:28:26currently actually present in my C or
14:28:28not. Okay. If that is not present in the
14:28:32C. So what you're going to do? You're
14:28:33going to face the data from my DB as
14:28:35usual. If this is present in C, we're
14:28:37going to get from our radius C. So first
14:28:40uh what we'll do uh as usual. So let's
14:28:42create a export as sync function and I'm
14:28:45simply going to do same get product by
14:28:47ID and this one I'm just going to do
14:28:49this one as fetch
14:28:51uh let's do single product. It will be
14:28:53easy to understand fetch single product
14:28:56from DB, right? Or database whatever you
14:28:59can do. So first of all what we need to
14:29:01do here, right? So okay, these will be
14:29:03same. So let's copy this
14:29:07and we'll just paste it here.
14:29:10So first we need to actually see that if
14:29:12that is present in the radius cast or
14:29:15not. So how we can do that? So we have
14:29:17to take a cast key, right? So I'm just
14:29:19going to do cash key and for this one
14:29:22let's do one thing. Let's uh create one
14:29:24method. Okay. So I'm simply going to do
14:29:27so let's go to the top maybe here. So
14:29:31here I'm just going to do a function and
14:29:33I'll do get product gas key and here
14:29:38we're going to get the product id. So
14:29:40this will be number and uh we are going
14:29:43to return a string. So here I'm simply
14:29:46going to create a key which will be
14:29:49products
14:29:50colon id because this will be single
14:29:53product but how we are going to get the
14:29:54single product. So this single product
14:29:56is nothing but your product ID. So that
14:29:59means let's say I have 1,000 products
14:30:01and I am storing the uh product with of
14:30:05ID 500. So it will become like this,
14:30:07right? So the products colon id colon
14:30:10500 something like this. So now this is
14:30:13done. So what will be the next step? So
14:30:15next will be first we need to see that
14:30:16okay this is present or not. If this is
14:30:18present we're going to return it. So we
14:30:20simply going to do get product by
14:30:24product cast key right and here we are
14:30:26going to pass the id and then I'm simply
14:30:28going to do con cast product. So this
14:30:32cast product will be a radius client dot
14:30:36get and this will be this cast key. So
14:30:39we simply checking if that id product.
14:30:42So this is a dynamic value right? So
14:30:44this can be 1 2 3 4. Consider let's take
14:30:47the example of 10. So if the id of 10
14:30:51product was not 10 product ID of product
14:30:5310 opposite id of product 10 the product
14:30:57which id is 10 if that is present in
14:31:00cash or not okay we simply checking that
14:31:03part if this is present so that means it
14:31:05will be a cash hit right so that data is
14:31:07present so I'm simply going to do if
14:31:09cash product if this is present so I'm
14:31:11just going to do a log and this will be
14:31:14a cash
14:31:16cast cash hit and And let's also pass
14:31:19the uh cast key here. Right. So I'm just
14:31:21going to do here uh what I'm doing cash
14:31:25key. So this will be cash hit. And then
14:31:28we are simply going to as usual return
14:31:30the response. So I'm just going to do
14:31:31return JSON dot parse.
14:31:35So this will be my cash product as
14:31:38product. This is done. Now if this is
14:31:42not present so as usual this will be
14:31:44cash miss.
14:31:46And then we're going to first get the
14:31:48product from our DB. So we have it
14:31:53fetch single product from DB
14:31:57pass the ID. First we're going to check
14:31:59that if the product is not present.
14:32:02We're going to return null. Okay. And
14:32:04then we're going to set this one in our
14:32:06cast. So now I'm just going to direct
14:32:08radisclient dot setx. And here we are
14:32:11going to pass the cast key. We're going
14:32:13to pass the TTL and also then I'm going
14:32:16to pass the actual product that I need
14:32:18to uh need to store. So this will be the
14:32:20product and this is done. And then I'm
14:32:22again going to do a log here and this
14:32:24will be catch
14:32:27set.
14:32:29Okay. What you have to return? You have
14:32:31to return the product here. And this is
14:32:33done. Okay. All right. So now let's run
14:32:35this. And also one thing I just paused
14:32:37it and I see that we make a mistake and
14:32:39that is uh here right if this is cast so
14:32:43it will be cast hit or this will be cast
14:32:45miss. Okay so this is one change we have
14:32:47to do. So now let's go here and then if
14:32:50I try to send this so you'll see that
14:32:53what you're getting we're getting cash
14:32:54missed and cash is now set. Now next
14:32:57time let's try to send once again and
14:33:00you'll see that now cash is hit. So that
14:33:02means the data is now present in your
14:33:04radius cast. So this is another example
14:33:07that we have done. Now another very very
14:33:08important one that you have to
14:33:09understand. Okay. So first let's see how
14:33:12I'm going to do it. So what I'll do
14:33:14right. So let's go to products endpoint
14:33:18and you will see that what we are
14:33:20getting right. So first of all let's do
14:33:21here. So I'm do 1 2 3 4 5 6 7. Okay. So
14:33:28we have seven data. So now uh I'll try
14:33:30to send this. So you can see that we
14:33:33getting this. Now let's go to the
14:33:35postman test that I have created and I'm
14:33:38just going to copy this. Okay, let's go
14:33:40to the uh add here. So I'm going to add
14:33:43the post and then I'll go to body and
14:33:46then I'm simply going to send this one.
14:33:48So this is added ID 8 and if I try to go
14:33:51here and try to send this you'll see
14:33:53that how many data you are getting.
14:33:55You're getting the ID 7. So you're not
14:33:57getting the ID
14:33:59uh the ID8 data. So what I mean the new
14:34:02data that we have added it's not coming
14:34:04here and the reason is very simple this
14:34:07is the concept of the stale caches you
14:34:09remember I just done this one
14:34:10practically so that means it is getting
14:34:12from a radius cast until unless that
14:34:14cash will be invalidated that will not
14:34:17come or else until unless the TTL will
14:34:19cross then only the new data will come
14:34:22but that is not the solution right so
14:34:23that means we have to have some kind of
14:34:26mechanism that whenever I'm going to
14:34:28create the data or whenever I'm going to
14:34:30update the data remember I mentioned
14:34:32that whenever there will be some update
14:34:34in the DB you need to invalidate the
14:34:36cast very very important concept so how
14:34:38we are going to do that to do this one
14:34:40let's go to our create product and you
14:34:42can see [snorts] that we are doing all
14:34:43of this whatever blah blah that is fine
14:34:45we don't have to do anything here so
14:34:47first what I'll do right so I'm just
14:34:49going to create a const and I'm just
14:34:52going to do newly created product
14:34:55so I'll do newly created product
14:34:58and this will be these whatever whatever
14:35:00we are doing here and now what I need to
14:35:03do right I need to invalidate the cash
14:35:06now remember I mentioned what the
14:35:07postgress is the source of truth right
14:35:09so whenever we going to create a product
14:35:10we need to delete the old list that is
14:35:14stored in our cast so that next time
14:35:16whenever we are going to face the latest
14:35:18data it is going to get the data from
14:35:20your postgress it's going to get the
14:35:22fresh data from postgress so that means
14:35:24we have to have a method which is going
14:35:27to delete the products
14:35:29from now delete all products or products
14:35:32all
14:35:36so this is what we have to do and at the
14:35:38end we're going to return the newly
14:35:39created product here which is fine so
14:35:41what this is going to do so this is
14:35:43going to actually delete that cash so
14:35:46now copy this and maybe let's do it here
14:35:49only right so I'm just going to do async
14:35:52function and I'll do delete product cash
14:35:56what this is going to return so this
14:35:57will be a promise
14:35:59void and here I'm simply going to do a
14:36:03and I'll do radius client dot delete and
14:36:07then I'm simply going to delete the
14:36:08product
14:36:10all cash key and then I'm simply going
14:36:13to do a log and you'll see that I'm just
14:36:15going to do a cash delete and then I'm
14:36:19just going to do products all and you'll
14:36:21see that whenever you're going to do
14:36:23that right now notice this cash delete
14:36:25will be triggered so now let's do in
14:36:28different way so First I will go to
14:36:30let's start with first one. So go to
14:36:31products. I'm going to send here. We are
14:36:34getting the new data because cash is now
14:36:35automatically invalidated using TTL.
14:36:38That is fine. Now I'll [snorts] go to
14:36:40post and I'm going to create one more
14:36:41data ID9. And you'll see that here it's
14:36:44getting cash is actually now deleted.
14:36:46And now if you go to immediately here
14:36:48right and try to send this you are
14:36:50getting the newly created data also.
14:36:52Fantastic right? So that means whenever
14:36:54you created a data whenever we updated
14:36:57the database we actually deleted our old
14:36:59radius cache that is present. So what
14:37:01will happen next time it's going to read
14:37:04the data immediately from your DB. It's
14:37:06not going to wait. So this is how you
14:37:08have to invalidate cash. So so see this
14:37:12part you have to master that when I'm
14:37:14going to invalidate the cash. No one is
14:37:15going to come and then tell you that
14:37:16okay whenever you are going to create
14:37:18product every time you have to delete
14:37:19cash. It's not like that you are
14:37:21getting. So what I'm trying to explain
14:37:22that based on that situation that or
14:37:25based on the project or based on the
14:37:26feature that you are creating you have
14:37:28to decide that when I have to delete the
14:37:30cash this example I'm just showing you
14:37:32based on the project that I have created
14:37:34this doesn't mean that every time you're
14:37:36going to create the product you have to
14:37:37delete the cash okay maybe yes but what
14:37:40I'm trying to say that based on project
14:37:42to project this will change but at the
14:37:44end the main concept will remain same so
14:37:47this is one now the same thing will be
14:37:50for what for will be for your uh update
14:37:52also. So whenever you're going to update
14:37:54any data right that time also you need
14:37:57to do what you need to actually
14:37:59uh delete or the cache okay because we
14:38:03have this update product this one right
14:38:05this so whenever I'm going to update so
14:38:07there is a possibility that this data
14:38:09will not be immediately updated so let's
14:38:11see if this is happening right so maybe
14:38:13I'm trying to send it here and this is
14:38:16now we are getting from caset whatever
14:38:19and then let's go to patch and what I'm
14:38:22going to I will try to update the first
14:38:25product stock from 30 to 5,000 and then
14:38:28I'll send it here and go to products and
14:38:32let's see what we getting. We are
14:38:33getting stock as 30 because this is
14:38:36going to still taking from your cash
14:38:38only. So that means whenever you're
14:38:39going to update the data that time also
14:38:42you need to invalidate the cash. So that
14:38:44means first of all what I need to do
14:38:45when I'm going to update so instead of
14:38:48get product by id first of all I need to
14:38:50get fetch product single product from
14:38:52database. So this is the first thing and
14:38:54then whenever I'm going to update the
14:38:56product that time also I need to do
14:38:58that. So I'm just going to do con
14:39:00product equal to this. [snorts]
14:39:02So first I'm going to do a and here I
14:39:05need to first delete the all product
14:39:08cash and at the same time I also need to
14:39:10delete the single product. Now you might
14:39:13be thinking okay what is this single
14:39:14product cache? This single product cache
14:39:16is nothing but this get product cash
14:39:18that we have created. So this also we
14:39:21need to uh delete. Now you might be
14:39:22asking why.
14:39:24Okay. Now consider that when we are
14:39:26updating a product this product with ID
14:39:29this we are updating from 5,000 stock to
14:39:3210,000. And if you try to go to this
14:39:35fetch product by ID now let's say this
14:39:37data is now currently stored in your H
14:39:40sorry in your C. When you are updating
14:39:42this product uh stock from 5,000 to
14:39:4510,000, there is a possibility that when
14:39:46you're going to send this, you are not
14:39:48going to get it. Now you're getting but
14:39:50immediately you're not going to get it
14:39:51because this data will be stored in your
14:39:53single product cache you're getting. So
14:39:55that means not only all product cash we
14:39:58need to delete which is this one single
14:40:00product cash also we need to delete
14:40:02because update will happen on a single
14:40:03product and it doesn't know that this
14:40:06product ID data is present in cash or
14:40:08not and at the same time you're updating
14:40:10the same product uh stock from 5,000 to
14:40:1310,000 means this cash also you need to
14:40:15delete you are getting what I'm trying
14:40:16to say so that mean this also you need
14:40:18to delete so to do this one let's go
14:40:21here right so I'm just going to do async
14:40:24function
14:40:25and I'll do delete
14:40:28single
14:40:30product cash. So here I'm just going to
14:40:33get the product ID which will be a
14:40:35number and here what will be the uh
14:40:38return type. So this also will be
14:40:39promise right? So it will be promise
14:40:42of void and here first of all what we
14:40:46need to check. So I'm just going to
14:40:48check the cast key and this will be get
14:40:51product cast key pass the product ID
14:40:56and then you're going to do a and I'll
14:40:58do radiusclient dot delete
14:41:01and then you're going to delete the cast
14:41:03key and then I'm simply going to do
14:41:05console dot log and I'll do cast delete
14:41:10and I'm simply going to do here cast key
14:41:13and this also we are going to call it
14:41:16here. So I'm just going to the a delete
14:41:18single product cash and here we need to
14:41:21pass the ID right what is the ID id is
14:41:24this ID we need to pass and then we
14:41:26going to return the product here
14:41:30and this is done so now to verify this
14:41:33first what I'll do right see what I'm
14:41:35doing first I'm going to send this okay
14:41:37so I'm going to request this so now it's
14:41:40going to first miss the cash next time
14:41:42it's going to hit the cash now I'm going
14:41:45to go to update and change this product
14:41:47ID stock from 5,000 to uh let's do
14:41:5115,000
14:41:53and I'm going to update this. Now if I
14:41:55go here right and try to send this
14:41:57you'll see that immediately you are
14:41:59getting 15,000. Why? Because this line
14:42:01is now deleting that product cash
14:42:03immediately. Also if you go to products
14:42:06and try to send this you see that you
14:42:07are getting immediately 15,000. You're
14:42:09getting this one. So that means both the
14:42:11whatever in both the endpoints we have
14:42:13added this one in cash we are
14:42:15invalidating both the cache whenever we
14:42:18are going to update this particular
14:42:19product in your DB. So this is how you
14:42:22have to understand the concept of cash
14:42:24aside pattern still cash isue and cash
14:42:27invalidation. I think you might not be
14:42:30thinking like these are very important
14:42:31concept. Okay these things you are going
14:42:33to use mostly whenever you're going to
14:42:34create any kind of grant. As I already
14:42:37mentioned in my previous videos, at the
14:42:39end of the day, whatever complex project
14:42:41you are creating, everything is CRUD. So
14:42:44what I mean by this, either you're going
14:42:45to create something or you're going to
14:42:47update something or you are going to
14:42:48list something or you're going to delete
14:42:50something. So all the things is CRUD. If
14:42:53you can master all of this right, you
14:42:55will be able to tackle any kind of
14:42:56complex project. So with this, I think
14:42:58we have almost covered most of the
14:43:00things. Now let's move to the next one
14:43:01which will be I'm going to give you some
14:43:02very basic idea how you can implement
14:43:04rate limiting in radius. All right. So
14:43:06now let's understand how we can create a
14:43:08simple rate limiter using radius. Okay.
14:43:11So first what I will do right. So let's
14:43:13go to middleware and maybe I'm just
14:43:15going to do rate uh limit dot middleware
14:43:23uh ts. Okay. So first of all what we
14:43:27need to uh do here. So first you have to
14:43:29decide that okay what will be your rate
14:43:31limiting rules. So what I mean by this
14:43:33so let's say we have a endpoint consider
14:43:36products endpoint or whatever endpoint
14:43:37that you're using that as a user that
14:43:40whenever your users will be using that
14:43:43particular endpoint is going to hit that
14:43:45particular endpoint how much or or how
14:43:48many request they can do in a certain
14:43:51time frame. So for example let's say
14:43:53they can do [snorts] five requests only
14:43:56within 30 seconds. So that will be your
14:43:59configuration and that will depend based
14:44:01on the app you're building based on the
14:44:03security and then there are lot of other
14:44:05factors. Okay. So in this case first we
14:44:07are going to take something like this.
14:44:09I'm just going to do a rate limit
14:44:13rate limit
14:44:15window seconds.
14:44:19So this will be I'm just going to give
14:44:21this one as 60 seconds. And also I'm
14:44:22just going to take one more which will
14:44:24be rate limit and I'll do this one as
14:44:27max requests.
14:44:30This will be let's do maximum 10 request
14:44:32or maybe five requests whatever you want
14:44:34to do. So now I'm just going to create a
14:44:36middleware. So I'm just going to do
14:44:38export async function and here I'm
14:44:41simply going to do this one as product
14:44:43rate limiter because we are doing
14:44:46something related to product and here we
14:44:49are going to have a request. So this
14:44:51will be the request from express.
14:44:57So let's import this, right? So I'm just
14:44:59going to import from
14:45:02express
14:45:09and then I'm also going to take a
14:45:11response which will be response right.
14:45:14So let's import the response also and
14:45:17also I'm going to import the next
14:45:19function
14:45:20and then I'm going to have a next
14:45:22middleware which is going to call the
14:45:23next middleware or next endpoint
14:45:26whatever we have. So here I'm simply
14:45:28going to do a try. Okay. So first of all
14:45:31what we need to do now here couple of
14:45:32things I wanted to mention. Okay. So you
14:45:34have to understand all of these each and
14:45:36every line what we are doing here. Also
14:45:38let's do a catch and I'm going to do
14:45:40error and I'll just going to log error
14:45:42here. Let's do rate limit
14:45:46radius error.
14:45:49And what we'll do right, I'm going to
14:45:51call the next with our error. So it's
14:45:54going to call this error middleware
14:45:56because if you go to the server.ts,
14:45:58we're using the middleware here. I think
14:46:00this one. Okay. So the so this is done.
14:46:04So now first of all, let's do one thing.
14:46:06Let's always at the end what we have to
14:46:08do. We have to call the next middleware
14:46:09or next route handler whatever we we
14:46:12have. So you have to call the next. This
14:46:14is important because if you don't do it,
14:46:16it will it will be stuck. Okay, this is
14:46:18a middle middleware. So it needs to call
14:46:20the next middleware or it needs to call
14:46:21the next what to say the next route
14:46:24handler. [snorts] Okay, first of all we
14:46:27need to understand that what we need to
14:46:28do right see whenever you're going to
14:46:30implement a real products and level of
14:46:32application this uh application this is
14:46:34what my understanding right or from my
14:46:36practical experience whenever you are
14:46:38going to implement this kind of rate
14:46:39limiting right. So these uh so first of
14:46:42all you have to work with IP right
14:46:44because whenever you're going to uh
14:46:47implement rate [snorts] limiting there
14:46:48has to be something with IP. So what I
14:46:50mean by IP? So let's say every user is
14:46:53going to have some IP, right? And each
14:46:54IP is going to get uh its own counter in
14:46:58radius because we using radius. And what
14:47:00will happen in the actual real
14:47:02production level pattern will be that
14:47:04will actually go behind a proxy or let's
14:47:06say there is a load balancer. So what I
14:47:09mean by this? So first of all, let's
14:47:10write all of this because this is
14:47:11important. So each IP is going to get or
14:47:14will get will get its own counter in
14:47:19radius. Okay. So this is the first
14:47:21thing. So let's say I have a rate limit,
14:47:23right? So I'm just going to do rate
14:47:25limit. I think this we've already this
14:47:26pattern colon products because we are
14:47:28creating a products middleware colon and
14:47:30let's say there is a IP. So something
14:47:32like this 127.0 blah blah whatever. And
14:47:35then [snorts]
14:47:36I'm also going to have a rate limit
14:47:40colon products
14:47:44products
14:47:46and then we have one something like
14:47:48this. So here what will happen right? So
14:47:51let's say there are multiple users will
14:47:53be using your application at the same
14:47:55time. What will happen that if one user
14:47:58crossing the limit? So let's say one
14:48:00user So let's say one user is crossing
14:48:05the limit. It's possible it will not
14:48:09going to it will not going to block
14:48:12everyone. Okay. So this is the main
14:48:14reason it's not going to block
14:48:17everyone.
14:48:19So that is the reason we need to have
14:48:21some it and this in real application or
14:48:25real products and pattern I'm going to
14:48:27do will be this will go behind a proxy
14:48:32or it can be a load balancer. Okay.
14:48:36So this IP handling whatever you have to
14:48:38do it needs extra configuration also
14:48:40it's not that much simple but for now
14:48:42what how we are going to do it. So for
14:48:44now I'm just going to do IP and I'm just
14:48:45going to take the request ip or else
14:48:48this will be unknown. Okay but I already
14:48:50mentioned this is how you have to do it.
14:48:52There can be lot of other configuration
14:48:53that you have to make sure that you're
14:48:55using also there is a possible that
14:48:57maybe that application that you're using
14:48:59uh that also has overseas audiences
14:49:02maybe the country that application you
14:49:04have maybe some from some other country
14:49:06you have a user. So lot of other things
14:49:08is there. So you have to [snorts]
14:49:10consider all of this but at the end the
14:49:12main idea is that if one user is
14:49:14crossing the limit it should not block
14:49:16other users because there is a
14:49:17possibility that 100 users thousand or
14:49:19lakh users are using your um application
14:49:23at the same time and then now I'm just
14:49:25going to take as usual rate limiter key.
14:49:29So I'm just going to do this one as
14:49:31let's do same only. So I'll do rate
14:49:33limit colon products
14:49:37colon and then here I'm going to pass
14:49:39the IP. So this will be my IP. Okay. So
14:49:42now first of [snorts] all what I need to
14:49:43do right I need to have a request count
14:49:45how many requests that particular user
14:49:48is doing. So here I'm just going to do a
14:49:50radius client dot and then I'm just
14:49:53going to do increment and here I'm going
14:49:54to have the rate limiter key. Okay. What
14:49:57increment is going to do? It's going to
14:49:59increase the request counter by one. And
14:50:01now this is where radius is very very
14:50:03good. Okay. So this is where radius is
14:50:06very very good
14:50:09here. Why? Because let's say you have
14:50:12multiple backend servers right? What
14:50:15will happen right? If you have multiple
14:50:16backend servers those many backend
14:50:19servers can share the same exact radius
14:50:22counter. [snorts]
14:50:22Okay. So this is actually very important
14:50:24concept. So now consider that we are
14:50:26storing this particular count in a
14:50:28normal JavaScript variable. Okay. not
14:50:30like this. So what will happen even
14:50:33consider you have multiple back end
14:50:34server that part I already mentioned
14:50:36each server is going to have its own
14:50:39separate count you're getting what I'm
14:50:41talking about so what will what is the
14:50:43downside so if each server is going to
14:50:45have it own separate count it's going to
14:50:47break the rate limiting okay because you
14:50:50consider your app is running on multiple
14:50:52servers and you're using some normal
14:50:55JavaScript variable so in that case it
14:50:58can actually break why because each
14:51:00server Let's say there is one server,
14:51:02second server, first server is going to
14:51:04have own separate count. Second server
14:51:06is going to have own separate count. And
14:51:07this is actually extremely helpful
14:51:09because radius is going to do what this
14:51:11multiple back end servers actually can
14:51:12share the same radius counter. So this
14:51:15will be the request count that we are
14:51:16going to increment. So now what I'm
14:51:18going to do right I'm simply going to do
14:51:20the request count is equal to equal to
14:51:22one and I'm going to explain what we are
14:51:24doing. So I'm just going to dive it and
14:51:26I'll do radiusclient doxpire.
14:51:29So I'm just going to give the rate
14:51:31limiter let limiter key and also I'm
14:51:34just going to give the rate limiter
14:51:36window second. So what we are doing
14:51:38here? So first of what expert is going
14:51:39to do is going to create a fixed time
14:51:41window for this particular counter. So
14:51:43we have a counter right. So now we are
14:51:46actually setting this expiry when the
14:51:48count is one. Okay. Now now think in
14:51:51this way right? So let's say if we reset
14:51:53this expiry on every request. So every
14:51:55time they're going to hit that request
14:51:57and we are going to reset this expiry.
14:51:59What will happen? This time window that
14:52:01we have, it's going to keeps moving. We
14:52:03can't do that. Okay? Because we are
14:52:05implementing a fixed window limiter. And
14:52:07this is also very very simple level,
14:52:08right? This is not even complex for this
14:52:12kind of simple fixed window limiter.
14:52:15What should happen right? Expiry should
14:52:17start with the first request. So that is
14:52:19the reason when the request count is
14:52:20one, we are actually setting this
14:52:22expiry. I hope this is clear. What will
14:52:24happen? Because this is actually 60. So
14:52:26after 60cond radius is going to delete
14:52:28this particular key and it's going to
14:52:31count again from phrase. Okay. So after
14:52:3360 it's going to delete and it's going
14:52:35to start counting from phrase. Very
14:52:37important. So I'm just going to write it
14:52:39here that after 60 seconds
14:52:43after 60 seconds
14:52:47radius will deletes this key and start
14:52:52counting from fresh. So I think this is
14:52:56done and then I'm just going to set some
14:52:58header. So I'm just going to do race dot
14:52:59set header and let's give this one as x
14:53:04rate limit
14:53:06limit
14:53:08limit
14:53:11and this will be your rate limiting max
14:53:13request. Also we are going to set one
14:53:16more. So I'll do set header and this
14:53:18will be x
14:53:21rate limit. And let's do remaining
14:53:24because we also need to check that how
14:53:26many is remaining. So I'm just going to
14:53:28do remaining. And how we going to get
14:53:30the remaining? So this will be very
14:53:32simple. So we do math do max. So I'm
14:53:34going to take the zero zero. And you
14:53:37have the rate limit max request correct
14:53:40versus your request count. Simple
14:53:43because this request count we are using
14:53:44here, right? So you're increasing this
14:53:45one. So every time they're going to do a
14:53:47request, it's going to increase the uh
14:53:49counter. So that means this is going to
14:53:51check that how many request is remaining
14:53:53within that time frame. If this request
14:53:56count that you have is greater than the
14:53:59rate limit max request. So what will
14:54:01happen? That means you've already
14:54:02exceeded the limit. So in that case we
14:54:04have to return. So I'm just going to do
14:54:06raise status and what will be the return
14:54:084 to9 because you're doing too many
14:54:10request and you'll see that in so many
14:54:12uh websites also you're going to get
14:54:14this kind of thing. So I'm going to do
14:54:16success will be false and message will
14:54:19be I'm just going to do this one as too
14:54:22many requests please try and later
14:54:26something like this
14:54:28right this is done and then if this is
14:54:30not the case we anyway is going to call
14:54:32the next so this is how you can create I
14:54:35think we have uh discussed each and
14:54:37every line so how we going to do that so
14:54:40go to your products uh sorry routes not
14:54:42products go to product router and here
14:54:44you simply going to do router dot use
14:54:47and for now I'm just going to do product
14:54:49rate limiter and this is done. So now
14:54:52let's save this and if you go here right
14:54:55maybe let's I'm just going to hit this
14:54:56endpoint here. So one time and let's do
14:54:592 3 4 5 6. So you're getting too many
14:55:04request please try again later. So you
14:55:07are going to immed uh is going to get it
14:55:09right. So until is going to reset again.
14:55:12All right. So I hope this is clear. This
14:55:13is very important concept. But again one
14:55:15thing I wanted to mention for now we are
14:55:17actually applying this for all the
14:55:18routes. That should not be the case.
14:55:20Maybe the uh application that you are
14:55:22building. Let's say in your case only
14:55:24one particular
14:55:26endpoint you have to apply product red
14:55:28limiter. So you can also apply in that
14:55:30particular uh endpoint label also. But
14:55:32for now we are applying on the overall
14:55:34but again the concept you have to
14:55:35understand. So with this I think that's
14:55:37all for this particular section. Now
14:55:39let's move on to the next one. All
14:55:40right. So now we are going to end this
14:55:42particular video with our last concept
14:55:44which will be pops up. So what is popsup
14:55:46right? So in so in SW we call that one
14:55:49as popsup but that actually means
14:55:51publish and subscribe. So first let's do
14:55:54one thing right. What are you going to
14:55:55do? Let's go here and I'm just going to
14:55:58do this one as radius popsup.
14:56:03DS. So as you uh I already mentioned
14:56:06that this will be publish and subscribe.
14:56:11So what publisher is going to do?
14:56:13Publisher is going to send a particular
14:56:15message. So here we are going to do
14:56:17publisher sends a message.
14:56:21What subscriber is going to do?
14:56:23Subscriber is going to listens
14:56:27and receives the message
14:56:31and there is another concept or you can
14:56:33consider this one as a mediator and that
14:56:35we call as channel. What's channel?
14:56:37Channel is actually the topic name.
14:56:39Okay, from both sides
14:56:43both sides use both side means publisher
14:56:46and the subscriber. So this is a very
14:56:48overview. Okay. Now uh it's kind of like
14:56:51a live messaging. Okay, it's not like
14:56:54any long-term storage or anything like
14:56:55that. So let's say in this particular
14:56:58project we're going to create a very
14:56:59simple popsup where we are going to
14:57:01let's say I'm just going to give you a
14:57:03very simple example like we're going to
14:57:04create a notification. So once uh admin
14:57:08or API is going to create the
14:57:09notification express is going to publish
14:57:11the event to the radius channel and then
14:57:14subscriber is going to receive it
14:57:16instantly. Okay. And then uh maybe we
14:57:19can do something like this. We are going
14:57:20to log that notification in another
14:57:22terminal. This is like very basic back
14:57:24end to back end live event. Uh we are
14:57:26going to implement. Okay. Now here uh
14:57:29when you're giving some interview right
14:57:31there is a possibility that you are
14:57:32going to get query from this particular
14:57:34concept because this is actually very
14:57:35important. Okay. Now what kind of uh
14:57:39questions that you might get okay that
14:57:40okay you mention that okay P mean
14:57:42publish right. So what publisher
14:57:45actually means and what publisher is
14:57:47going to send a message where. So you
14:57:49have to mention that publisher is going
14:57:50to send a message to a radius channel.
14:57:52Okay, it is going to send a message to a
14:57:55radius channel. Subscriber is going to
14:57:57listen and receive the message from that
14:57:59particular channel. So that is a listen
14:58:01channel is like a topic name that both
14:58:02side is going to use or what I when I
14:58:06learned I remember I usually used to
14:58:08remember this one like this the channel
14:58:10is like a mediator. So you have one
14:58:11person
14:58:13within two person and that one person is
14:58:15actually taking the message from one
14:58:17person and it's going to sending the
14:58:19message to another person. The second
14:58:20person who is actually receiving the
14:58:22message.
14:58:24So now uh let's uh do this one with a
14:58:26very simple example first. So first
14:58:29let's do one thing. I'm just going to
14:58:31copy this one from here. Right? So let's
14:58:33go
14:58:35till this part. We need
14:58:39this one and then I'll paste it here. So
14:58:42first of all what I will do we going to
14:58:44have a channel as I already mentioned.
14:58:46So there will be a channel and I'm just
14:58:47going to do this one as demo
14:58:49notifications.
14:58:53Okay. So here I'll do async function
14:58:56run.
14:58:58So first uh when you're going to
14:59:01implement a pub sub right it actually
14:59:04needs two clients. So needs two clients.
14:59:08One client
14:59:10will be to publish
14:59:15and second one to subscribe. This is
14:59:19also important concept and prerequisite
14:59:22like that you need to know all of these.
14:59:24So there will be publisher. So publisher
14:59:26will be create client.
14:59:29This create client you're going to get
14:59:30from radius. And here you're going to
14:59:32pass the URL which will be your radius
14:59:34URL. Then you're going to have a
14:59:36subscriber. Right? So this will be your
14:59:38subscriber and this also will be your
14:59:40create client and this will be your URL
14:59:42which will be your radius URL. Okay. So
14:59:45now I have two client. Now publisher can
14:59:47send a message or publish a message via
14:59:50a channel and subscriber is going to
14:59:52receive that particular uh message from
14:59:54that particular channel. So now here I'm
14:59:57just going to have it. So I do publisher
14:59:59dot connect. So first we need to
15:00:01connect. Same we need to do for
15:00:03subscriber. So I'll do subscriber dot
15:00:06connect.
15:00:08Okay. So now let's do a log here. So I'm
15:00:11just going to do a log and I'll do
15:00:13publisher
15:00:15connected
15:00:17and subscriber connected.
15:00:22Okay. Also you can check the ping also.
15:00:24Right. So let's say you want to check
15:00:26the ping. So I'm just going to do ping.
15:00:30So, and here I'm simply going to do a
15:00:33publisher
15:00:34dotping.
15:00:38Okay. And then maybe what else? Maybe
15:00:40let's do one more here. And I'm just
15:00:42going to do subscriber
15:00:48subscriber
15:00:50listens.
15:00:52Okay. So this is the first step that we
15:00:54need to do. Now one very very important
15:00:57concept when subscriber is going to
15:00:58listen that subscriber
15:01:03must be
15:01:06active
15:01:07before publish.
15:01:10Okay why this is very important because
15:01:12if nobody nobody is listening right so
15:01:15let's say there is no one to listen when
15:01:18publisher is going to publish that
15:01:19message it might be missed. So it's
15:01:21actually very important as that whatever
15:01:23subscriber that you're using that
15:01:25subscriber is actually responsible for
15:01:29consuming that message via that channel
15:01:31from your publisher. So that subscriber
15:01:33must be active and now what we going to
15:01:36do right so
15:01:38we'll take subscriber and this is going
15:01:40to give this subscribe method and it's
15:01:43going to receive the channels you can
15:01:44see that you have to pass the channel
15:01:45and it's going to receive the message
15:01:47correct. So now what you're going to do
15:01:49simply so I'm just going to do con data
15:01:53and I'm simply going to do JSON.parts.
15:01:55I'm going to get the message and then
15:01:58I'll just do some log here. So do
15:02:00subscriber
15:02:02received and also let's do some more
15:02:05logging here. And I'm just going to log.
15:02:08So let's do here title. So I'm just
15:02:11going to log a title. And I'm just going
15:02:12to do data dot title.
15:02:15And here also let's do one more which
15:02:17will be data dot message.
15:02:22So this will be data dot message. Okay.
15:02:26So now what we're going to do so I'm
15:02:28just going to do another log here and
15:02:30let's do this one as subscribed
15:02:34to channel and then we're going to pass
15:02:37the channel here. Okay. So now this is
15:02:40how subscriber is going to receive. Now
15:02:43this is not a done. Why? because
15:02:45publisher haven't sent the event yet,
15:02:47right? So publisher needs to send the
15:02:49event. So now this is what we're going
15:02:51to just start. So I'm just going to do
15:02:53publisher
15:02:54is now sending the event.
15:02:59Okay. And then I'm simply going to take
15:03:01the event data here. So this will be our
15:03:03actual data. So here I'm just going to
15:03:05take a title and this will be radius
15:03:09course.
15:03:10And then I'm just going to have a
15:03:12message and I'm going to do pubsub
15:03:16demo.
15:03:18Okay, so this is the event. So now
15:03:20publisher is going to send the message
15:03:23to the channel immediately. Okay, how
15:03:25it's going to do that? So I'm just going
15:03:26to do con. So I'll do receivers and this
15:03:30will be have it. So we're going to have
15:03:32the publisher. This publisher is going
15:03:34to have now publish. Okay. So this will
15:03:36be a publish method not subscribe. So
15:03:39this will be publish then you're going
15:03:41to pass the channel and then you're
15:03:43going to do JSON.stify what you have to
15:03:46pass you have to pass this event and
15:03:48this event this subscriber is going to
15:03:50receive via this particular channel
15:03:52which is the message that it's receiving
15:03:54here. Okay. And then we can also do some
15:03:57log here and then I'm simply going to do
15:03:59publish event
15:04:03and also let's log here. I'm just going
15:04:07to do active subscribers.
15:04:13Okay. And these will be receivers.
15:04:17Now what we are going to do right, we
15:04:19are going to so let's do one thing. We
15:04:21are going to have some small weight so
15:04:24that whenever subscriber is going to
15:04:26receive it, it's going to log okay
15:04:28before it's going to exit. So I'm just
15:04:30going to grab it. So you can simply do a
15:04:31new promise here. normal concept. Take a
15:04:34resolve and you're simply going to do a
15:04:36resolve. Sorry, set time out. Set time
15:04:39out. And I'm just going to resolve
15:04:42and I'm just going to [clears throat]
15:04:43give 300. Okay. So now I think this is
15:04:47done also. Uh what else? Maybe also we
15:04:51need to unsubscribe now. So I'm just
15:04:52going to do subscribe dot unsubscribe.
15:04:55We're going to pass the channel
15:04:58and then we're going to quit. Quit is
15:04:59again the same thing. So you'll do
15:05:01subscriber doquit and you're also going
15:05:04to do publisher doquit
15:05:07and then let's [clears throat] do one
15:05:09more log here and this will be pubsub
15:05:15demo done. So the main thing you have to
15:05:18understand there are a couple of key
15:05:20points. First one is that pubs sub is
15:05:22nothing but it's like a live messaging.
15:05:24Subscriber must be active before publish
15:05:28because you see that subscriber is going
15:05:29to subscribe. It's going to get the
15:05:31event data before publisher is going to
15:05:34publish. It has to be active or else
15:05:36once it's going to publish if the
15:05:37subscriber is not active it's not going
15:05:39to work because there is no no one is to
15:05:42receive who is going to receive the
15:05:44data. Okay. So this is one important
15:05:45concept and another important concept
15:05:48popsub is going to or popsub doesn't
15:05:51store messages permanently. Okay, this
15:05:53is another important concept. So go to
15:05:55package dojson and I'm just going to
15:05:58copy this
15:06:00run it. So I'll do radius popsub
15:06:04and this will be let's copy this.
15:06:10Okay. And here I'm just going to run
15:06:14this.
15:06:16So npm run
15:06:18and then enter.
15:06:21See again I've done mistake. We have to
15:06:23run this right. So let's go here. We
15:06:26have to just run this. We'll copy this.
15:06:32I'll do popsub.
15:06:36Okay. So let's see what is happening
15:06:38here. So I'll do clear.
15:06:41All right. So fantastic. So you can see
15:06:43that we have publisher connected. Let's
15:06:44go one by one. Subscriber connected
15:06:49ping pong. You are getting subscriber
15:06:51listens. Now here you will notice one
15:06:54thing subscriber listen. Now you say
15:06:56subscribe to channel which is this this
15:06:58one. So before even though this is
15:07:00active it's not going to receive the
15:07:02data. Why? Publisher needs to publish.
15:07:04Correct. So that's why getting
15:07:07subscribed to channel publisher is now
15:07:09sending event. Now you can see that
15:07:11you're going to get subscriber received.
15:07:13So title ready course blah blah message
15:07:16whatever you're sending publish the
15:07:17event active subscriber is one and pops
15:07:20up demo is done. The main point is again
15:07:22I'm repeating again and again when
15:07:23you're going to implement this one in a
15:07:25real project your subscriber has to be
15:07:27active before publisher is going to
15:07:28publish. If this is not the case you're
15:07:30not going to work. Okay. So this is one
15:07:32important concept. So with this I think
15:07:35uh this part is also completed. So let's
15:07:38do one thing right in the next section
15:07:39I'm going to show you one very simple
15:07:41example on this project context that how
15:07:44we are going to implement this one
15:07:45practically. So let's do this one in the
15:07:47next part. All right. So now let's end
15:07:49this particular video with the one
15:07:51practical example that I'm going to
15:07:53implement here. So first of all I think
15:07:54we have already discussed the concept
15:07:56right subscriber. I'm not going to
15:07:57repeat the same thing again and again.
15:07:59So first thing let's create one folder
15:08:01here and I'm just going to give this one
15:08:02as subscribers.
15:08:04Okay. So this will be the first thing
15:08:06and let's create this one as so do
15:08:08notification
15:08:13dots subscriber dot ts. So this is the
15:08:17first thing and then also let's rename
15:08:19copy this go to controllers and I'm just
15:08:23going to do notification dot controller
15:08:27ts also we'll go to routes I'll do
15:08:30notification dot routes dot ts so first
15:08:35let's start with the subscriber right so
15:08:37first of all what we need so let's go
15:08:39here I need to copy some of the things
15:08:41we need the create client
15:08:43uh also okay let's copy these to first
15:08:47I'm going to paste it here also you need
15:08:50to have a notification channel okay so
15:08:52for this one what we are going to do
15:08:54right so let's create here only maybe we
15:08:56don't need another file so I'm just
15:08:58going to do con and I'll do notification
15:09:03channel and this will be notifications
15:09:06so let's see what actually we are doing
15:09:08here and I'm just going to take export
15:09:12not export I think let's take in case in
15:09:14other uh file else we need it. So I'll
15:09:17do notifications
15:09:19payload.
15:09:20So for now I'm going to keep very very
15:09:22simple. So I'll do id. So this will be a
15:09:25string and also let's take a title. This
15:09:28also will be a string. Let's take a
15:09:31message.
15:09:33This will be string. And let's take a
15:09:36created
15:09:37at this also will be a string. Okay. Now
15:09:42uh what we are going to do right first
15:09:43of all uh let's create one more method
15:09:46here. So I'm just going to do async
15:09:48function and I'm just going to do
15:09:51publish notification.
15:09:55So here I'm just going to get the
15:09:56notification. The type will be
15:09:58notification payload and this will be
15:10:01the promise void.
15:10:04What we are going to do simply so
15:10:06publisher is going to do what? publisher
15:10:08is going to send the live message to
15:10:10radius. Okay. So here we are going to do
15:10:12ait. So I'm just going to take the
15:10:14radius client dot. So it's going to do a
15:10:18publish. So it's going to publish to
15:10:20your notification channel.
15:10:23And here I'm just going to pass the
15:10:25JSON.stringify. What notification is
15:10:27going to pass this notification. If you
15:10:29want you can also do notification.
15:10:31Right?
15:10:36That's it. So this will be to publish
15:10:39it, right? So now let's save this. So
15:10:41now we need to work on the subscriber.
15:10:45So here uh we already have
15:10:49create radius. We haven't
15:10:53created uh radius. So we going to use
15:10:55now. So first of all, let's do one
15:10:57thing. So here we are going to create
15:10:58our subscriber client. So I'm just going
15:11:00to do subscriber client. So this will be
15:11:03here. We need the create client and I'm
15:11:05just going to do URL and this will be
15:11:07your radius URL. So radius URL we need
15:11:10to just copy this from here
15:11:20we can do and this will be ready. Okay.
15:11:24So first I'm just going to do
15:11:25subscriberclient
15:11:26dot on let's give one error in case any
15:11:30error and here I'm simply going to
15:11:34log one error
15:11:39okay we'll do subs radius error
15:11:43and this will be error so this is the
15:11:45first thing now what we're going to do
15:11:47right so we are going to start our
15:11:49notific sorry subscriber notification so
15:11:52I'll do as sync function
15:11:53and I'll do start notification
15:11:57subscriber.
15:12:00So first what we need to do just see
15:12:03this whatever we have done here. So what
15:12:05we have done we have done the connect.
15:12:07So here first [snorts] we need to
15:12:08connect. So I'll do a subscriber client
15:12:12dot connect.
15:12:14So the first thing now what I need to do
15:12:17right this subscriber needs to tell
15:12:20radius okay I want to listen to this
15:12:22particular channel which channel the
15:12:23notification channel that we have
15:12:25created this is the channel so here I'm
15:12:28simply going to do and now it's your
15:12:30task is that you have to subscribe to
15:12:33this particular notification channel
15:12:35right and also you're going to receive a
15:12:38message
15:12:40and here I'm just going to do a try and
15:12:43uh in the try. So let in the catch what
15:12:46you can do right in the catch you can
15:12:47maybe just uh do something like this log
15:12:52and then we can just do new notification
15:12:55in sort I'm doing received
15:12:59right so this will be new and here we
15:13:01can just get the render the message here
15:13:04in the try first of all I'm just going
15:13:05to do con notification
15:13:09and this will be JSON dotparse so here
15:13:13we are going to get the message and this
15:13:15will be as and we're going to pass this
15:13:18right. So you can pass all of these or
15:13:20you can pass as notification payload.
15:13:25We can directly pass it here.
15:13:28Okay. So this is done and then I'm going
15:13:31to do a couple of logs so that we can
15:13:33understand. So first I'm going to do new
15:13:34notification
15:13:36received.
15:13:38Then I'll log it here. So I simply going
15:13:41to do title. So this will be your
15:13:46this notification dot title.
15:13:50Copy this. We'll do message and created
15:13:52at right. So do message and this will be
15:13:56created at.
15:14:01That's it. Okay. So this is done. So now
15:14:04uh what else? I think this should be
15:14:06fine. Now we have to call this. So now
15:14:09we are going to do start notification
15:14:12subscriber dot catch. Here I'm going to
15:14:15get error and I'll simply just do
15:14:18console dot error. And here I'm just
15:14:22going to do fail to start notification
15:14:25and I'll do error and then we'll do
15:14:27process do.exit
15:14:31of one.
15:14:33So this is what we need to do. Okay. So
15:14:36now not yet completed. Why? We need to
15:14:39publish the notification. We we haven't
15:14:40the publish. This is what we have
15:14:42learned so far, right? Subscriber is
15:14:43going to subscribe and subscribe is must
15:14:46be active but publisher is going to
15:14:48publish. So where we are going to do
15:14:50that for this one? We need to implement
15:14:52our uh this uh controller. So let's go
15:14:54here and then I'm just going to copy
15:14:57this
15:14:58paste it here and then I'm do export as
15:15:01sync function and this will be my
15:15:04publish notification
15:15:08controller.
15:15:09Okay. So here we're going to get the
15:15:12request which will be request response.
15:15:15This will be response and we also need
15:15:17the next which will be your next
15:15:22function.
15:15:24So now here what we have to do first. So
15:15:26we'll do try and this is the place where
15:15:30you have to publish it.
15:15:33So I'm just going to take the error and
15:15:35then we're going to pass in next with
15:15:38error. So in the try what are the things
15:15:41you have to do? First you're going to
15:15:43get the title and body. Let uh title and
15:15:45message. Let's say you have a UI and
15:15:47from the UI you're going to receive it.
15:15:48Correct? So you're going to get what?
15:15:50Title and message. these two things from
15:15:53request dot body this title dot request
15:15:57see title dot message we are having in
15:15:59the payload and then if you do some some
15:16:02uh check here that if title is not
15:16:03missing I'm not doing all of this now so
15:16:05here I'm simply going to do now create
15:16:07the notification and this notification
15:16:10will be id so this will be your date dot
15:16:12now
15:16:14dot to string
15:16:17then you're going to pass the title
15:16:18you're going to pass the message and
15:16:21also So created at we have to also pass
15:16:23the created at this one and this will be
15:16:27new date
15:16:30to ISO string. So this will be your
15:16:33notification and this is the place now
15:16:34we are going to publish. So this is
15:16:37where publisher is going to publish is
15:16:39going to publish. So do have it. So we
15:16:44do publisher notification. Sorry publish
15:16:46notification. I think we have to do
15:16:48publish notification. We have to export
15:16:50it. So we'll do export publish
15:16:53notification. So this publish
15:16:56notification
15:16:58is going to
15:17:00get the notification. This is the
15:17:01notification you're getting the flow. So
15:17:04this one you're going to let's say you
15:17:05have a UI you're going to get from UI.
15:17:06You are publishing the notification.
15:17:08This is going to [snorts] do what? It's
15:17:09going to publish. See we are using
15:17:11latest client to publish this one
15:17:14here. Right? This part this this one.
15:17:18and then subscriber is going to
15:17:19subscribe. So now I think this is done
15:17:22and then at the end what you can do you
15:17:23can simply just do array dot status of
15:17:25201
15:17:28dot JSON and you're going to do success
15:17:33will be true
15:17:35message
15:17:37I'm going to do notification
15:17:40published
15:17:42successfully
15:17:45and you can also pass the data. So let's
15:17:47say id will be notification do id and
15:17:51this is done. Okay. So this is what I
15:17:53need. So now what we can do right. So
15:17:56let's go to routes.
15:17:59So let's copy this. Let's copy this
15:18:02part. What notification routes and this
15:18:05we don't need. And this will be my
15:18:09notification controller. And I'm just
15:18:12going to do this one as notification
15:18:14controller.
15:18:17Now I'm simply going to do router dot
15:18:20post
15:18:22and this will be notification controller
15:18:24dotpublish notification and you're just
15:18:27going to do export default and this will
15:18:29be your router and this is done but this
15:18:32is not yet completed why in your root
15:18:34you have to use this. So go here and
15:18:37then simply copy this
15:18:40and this will be your notifications
15:18:45right and this view notification
15:18:49what we are using here
15:18:53okay let's import this I think we have
15:18:54to import
15:18:57so these will be your / notification
15:19:00routes
15:19:04notification and loads.
15:19:08That's it. So I think this is done. So
15:19:11now how we are going to check it? First
15:19:12let's see if we are getting any error or
15:19:14not. I think this is working right. It's
15:19:16working. So first let me just copy that.
15:19:20I'm just going to copy this
15:19:23and I'll go to my package.json
15:19:28and then I'll just add this here. So
15:19:30we'll do uh source/subscribers
15:19:34right this is what you're using
15:19:37subscribers notification dot subscriber
15:19:40ts so this is one and now what I can do
15:19:44right so let's run it here so I'm just
15:19:46going to do npm run subscriber
15:19:54okay so now this is running so first
15:19:56what I going to do right so let's copy
15:19:58that curl here. So, I'm just going to
15:20:00copy this.
15:20:02Go to Postman and I'm going to do
15:20:05import. Let's copy and then I'm just
15:20:08going to run it on my radius full quotes
15:20:13and then let's send it here. We're
15:20:16getting four. Okay, what we are using?
15:20:18Let's see.
15:20:20Our API will not be there.
15:20:24So, notification published successfully.
15:20:26And you can see what you are getting.
15:20:28New notification received. Fantastic.
15:20:30Right here. So this title order created
15:20:33message. This has been created
15:20:34successfully. So from where you are
15:20:36getting this one.
15:20:38So if you go here right new notification
15:20:40received title message and created at.
15:20:43Okay. So that means once you're
15:20:45publishing subscriber is able to
15:20:47subscribe that one and it's going to
15:20:50actually getting the data from publisher
15:20:51via this notification channel. So this
15:20:53is how we have to practically implement
15:20:55this logic. Okay. This is very very
15:20:57simple way I've implemented and if you
15:20:59just do this process multiple times you
15:21:01see that how much easier it will be for
15:21:03you to implement all of these. Okay. So
15:21:05with this I think we have completed this
15:21:07particular video. So let me know what
15:21:09you think. Uh as I already mentioned in
15:21:11the intro if I'm getting good response
15:21:13as I already mentioned I'm not going to
15:21:15do see part two. If I get good response
15:21:17from this particular video I'm going to
15:21:19create advance part is very very simple.
15:21:22If this video let's say getting 5,000 or
15:21:2410,000 views, there is no point of
15:21:26spending this much effort of creating a
15:21:28part two, right? Uh so with that that's
15:21:30all for this particular video. I will
15:21:33see you in my next video. Till then good
15:21:34luck and peace. All right, I hope that
15:21:37you have completed the previous section
15:21:39uh which was on radics. So with this now
15:21:41let's start. So this will be very
15:21:43important one. Okay. And in this one
15:21:44you're going to actually understand some
15:21:45of the very important concept that you
15:21:47are going to use in lot of projects. So
15:21:49because file upload, image upload and
15:21:51all of these right you are actually
15:21:52going to use and these are very very
15:21:55practical. So what you're going to do
15:21:56right consider you are admin right. So
15:21:59what we are going to do right so admin
15:22:01will be upload some images right now in
15:22:03this one we will actually take the
15:22:05functionality simple but we are going to
15:22:06understand the concept uh better way.
15:22:09Concept means the flow. So admin will be
15:22:11able to upload images and then admin
15:22:14will be able to see all your images.
15:22:16Correct? So admin will be create images
15:22:18and admin will be able to fetch all your
15:22:20images. So these two routes we have and
15:22:22then we have something called delete.
15:22:24But how this is going to work? Consider
15:22:26this is your application right and see
15:22:29how easier I will explain this one. So
15:22:31this is your application and this is
15:22:32your DB. Okay. So this is let's say your
15:22:35DB. What we are going to see till this
15:22:38time whatever we have done this CR what
15:22:40we used to do. So we usually do some
15:22:42functionality. we interact with our DB
15:22:45and then we directly uh store this
15:22:47particular information in our DB. But
15:22:49when we work with assets, it doesn't
15:22:51work like that. Instead of directly
15:22:54storing the image in your uh DB, what
15:22:57you're going to do right, we not going
15:22:59to do that. So we have something called
15:23:00cloud storage CS. I'm just writing this
15:23:04cloud storage can be anything. See in
15:23:05our case we're using cloud unit because
15:23:07it easier and also you can use AWS
15:23:10S3 or you can use cloudfare lot of other
15:23:13things. So at the end the concept will
15:23:15be same. So you have something called a
15:23:17storage. What you're going to do right
15:23:19you are actually going to store your
15:23:21images in your uh storage. So it will be
15:23:24like this. So this let me select this
15:23:26one. So from your application it is
15:23:29going to interact with your storage.
15:23:31Storage is going to do what? It's
15:23:32actually going to store all your images.
15:23:34So storage is going to keep all your
15:23:36images and then what storage is going to
15:23:39do right storage is going to give you
15:23:40some information that we are going to
15:23:42store in our DB. So what will be that
15:23:43information? That information will be
15:23:45our image URL because see at the end you
15:23:48need to keep a track of your assets.
15:23:50Right? So now what will be uh the
15:23:53responsibility of your DB?
15:23:54Responsibility of your DB will be to
15:23:56hold the information that is provided by
15:23:58the cloud storage. So that means once we
15:24:01store the image to our cloud storage
15:24:03cloud storage is going to give you two
15:24:04things. So first one let's say it's
15:24:06going to give a URL and this will be
15:24:08your actual image URL that we are going
15:24:09to store. So this will be your image
15:24:11URL. Okay. Second it's going to give you
15:24:14a unique ID. Now this unique ID can
15:24:16differ. For example in cloudary we call
15:24:18that one as cloudinary public ID. In S
15:24:20S3 we call something else. In other uh
15:24:23storage we call something else. That
15:24:24doesn't matter. But at the end it's
15:24:26going to give you a unique ID. And this
15:24:28unique ID will be attached to this
15:24:30particular asset. So that means how why
15:24:32actually you need this unique ID and you
15:24:34are going to understand this one in a
15:24:36minute. So that means this cloud storage
15:24:38is going to give you two information.
15:24:39First one will be your image URL and
15:24:41second one will be one unique ID that is
15:24:43related to this particular asset. And
15:24:46then what we will do we are going to
15:24:48store this URL and this ID to our DB. So
15:24:51that means what we are doing that we are
15:24:52not directly storing the image or videos
15:24:54in our DB. We are storing the image and
15:24:56videos in our cloud storage. Cloud
15:24:58storage is going to send that
15:25:00information and that information we're
15:25:01going to store in our DB. Now why
15:25:04actually we need this unique ID.
15:25:06Consider this is your application and
15:25:09this is your DB. In your DB you have 10
15:25:11storage uh saved. So you have 10 storage
15:25:15and this is let's say your cloud
15:25:16storage. Right? Now what actually these
15:25:1910 asset is going to consist? So each
15:25:21and every asset is going to have your
15:25:23URL and it's going to have your ID.
15:25:25Right?
15:25:27Now let's say what we have to do right
15:25:28from this side admin needs to delete one
15:25:31particular asset. So when we are going
15:25:33to delete the asset we can't just
15:25:35directly delete that particular asset
15:25:36from our DB. Why? Because at the same
15:25:39time we need to delete this particular
15:25:41uh asset from our cloud also. But in
15:25:44that case how you're going to understand
15:25:45okay this particular image URL actually
15:25:48stored in which part in which image or
15:25:50basically what I'm trying to say. So
15:25:52let's say let's uh understand in a
15:25:54simpler way. Let's say you have 10
15:25:55assets uh stored. Correct. So each and
15:25:57every asset is going to have your URL
15:25:59and the ID. So you have 10 assets URL 10
15:26:03assets ID. Okay. When we are going to
15:26:06delete this particular asset from our DB
15:26:08which you can directly do this one.
15:26:09Let's say you directly deleted this one
15:26:10from your DB. So from DB it is not
15:26:13present. But see the problem is in your
15:26:15cloudinary storage or in your cloud
15:26:17storage that asset is still present. So
15:26:19now to under identify that okay this
15:26:21particular asset is related to this
15:26:23particular asset in our DB. We need this
15:26:26ID. So we're getting so using this
15:26:28particular ID now what we going to do
15:26:29right? Two things we going to do. We are
15:26:31going to delete this particular asset
15:26:32from our DB. At the same time using this
15:26:36ID we are going to delete this
15:26:37particular asset from our storage also.
15:26:39So that means when we're going to
15:26:40delete, we are going to delete from two
15:26:41places. We are going to delete from our
15:26:43DB at the same time we are going to
15:26:45delete from our cloud storage and to
15:26:46delete from the cloud storage we need
15:26:48this particular unique ID. So this will
15:26:51be the order flow and radius one you
15:26:53will understand once you implement
15:26:54because I hope you have complete again
15:26:55I'm repeating okay you have to complete
15:26:57the previous video that is mandatory
15:26:59then only you can understand because I'm
15:27:00not going to cover radius concept in
15:27:02this one. This will be completely
15:27:03practical. So first this will be the
15:27:05overall flow. First what we're going to
15:27:07do right to go to cloudinary.com
15:27:10and then just sign up for free. Okay. So
15:27:12I'm just going to sign up using Google.
15:27:14I'll select this account and you'll see
15:27:15that I already have so many assets uh
15:27:18already uploaded here because I usually
15:27:20use this one from my YouTube uh videos.
15:27:22One thing I wanted to mention please do
15:27:24not use my credences because I've seen
15:27:25this one in the past. Some of you
15:27:27actually used which is not correct.
15:27:28Okay. So please create free account and
15:27:31then use. So you see that for example
15:27:33this one. I haven't even uploaded all of
15:27:35this right. I don't know from where it
15:27:36is all these are coming. So don't do
15:27:39[snorts] not use this. What you're going
15:27:40to do, right? You have to go to go to
15:27:43home
15:27:46and you'll see that you have this API
15:27:47key, right? So you have to go to this
15:27:49API key and you're going to get three
15:27:50things. Okay, the first one will be your
15:27:52cloud name. So this will be your cloud
15:27:54name. So if you go back, I wanted to
15:27:56show this. This is important because you
15:27:58need the cloud name. Okay, so this is
15:28:00your cloud name. Then you go to API
15:28:02keys. You need the API key and the API
15:28:05secret. So three things we need. Okay,
15:28:07first of all, let's do one thing. Let's
15:28:09go to our application and let's do one
15:28:10by one. Go to event uh sorry env.
15:28:14And I'm just going to create cloudinary
15:28:17cloud name
15:28:20cloudinary
15:28:22cloudinary
15:28:24uh what is that? Cloud uh no cloudinary
15:28:28API key.
15:28:30And then I'm just going to do cloudinary
15:28:33API secret. So these three things we
15:28:35need. So now let's go here. So I'm just
15:28:38going to copy. So this is my cloud name.
15:28:40Okay, this will be your cloud name. You
15:28:42can also check it. So here you can see
15:28:44this is cloud name. So just paste it.
15:28:46Copy the API key or I'll copy from here.
15:28:49Paste it. And then this will be the API
15:28:51secret. So I'm going to use this. So
15:28:53I'll copy and then I'm going to paste it
15:28:56here. Okay. So now what I'm going to do,
15:28:58right? So this will be the prerequisite.
15:29:01Now what I'll do, right? So let's close
15:29:03this and then I will give you one
15:29:05homework and this homework will be uh
15:29:08you have to do this go to your env
15:29:11here okay cloudinary API key cloudinary
15:29:14secret and then try to use using env dot
15:29:16this one I'm intentionally not doing
15:29:18this one so this one will be for your
15:29:20practice so add these three here and
15:29:22then we you are going to use this one
15:29:23using envi
15:29:28cloudname okay so this will be the first
15:29:30thing second what you're going to do
15:29:32right so Let's go here and we need a
15:29:35cloudinary package. So I do npm install
15:29:38cloudinary and also we need malter.
15:29:41Okay. So molter is a package that we
15:29:44need for our uh asset related uh work
15:29:46whenever we are going to do. So let me
15:29:48just quickly so this is very slow man.
15:29:51So I'll do molter in express node
15:29:54project.
15:29:57R this will be okay. So this is a
15:30:00middleware that handles multipart form
15:30:02data right it usually used for uploading
15:30:04files images PDF videos and all these
15:30:06things right so when we are going to use
15:30:08this so first of all we need to install
15:30:10the malter and also you need the multter
15:30:11type so do npm install- d types malter
15:30:14so copy this also and then we going to
15:30:17install this also
15:30:19all right so this is done next what we
15:30:22need we also going to need our IO so I'm
15:30:25just going to do IO radius.
15:30:29Okay. And also we need B MQ. So this
15:30:32will be for our background jobs that
15:30:34we're going to do later. But let's
15:30:35install this one at once. So we're going
15:30:37to do this one.
15:30:41Okay. So this is done. All right. So now
15:30:44what we're going to do right, let's do
15:30:46uh uh let's do this particular section,
15:30:48right? Uh slowly. Before doing this one,
15:30:52let's go to our docker compose. And we
15:30:55actually need to add some more uh one
15:30:57more service here. So what I'm going to
15:30:59do right, let's go here. Enter. And I'll
15:31:04add one more. So I'll do radius.
15:31:07And here we are going to do this one
15:31:09will be image.
15:31:11So image will be radius colon 7. And let
15:31:14me check the name alpine.
15:31:18Okay. Then we need the container name.
15:31:20So I'm going to do container name.
15:31:22Container name. Let's give this one as
15:31:24what I'll do right uh node js capstone
15:31:28project radius.
15:31:33Okay. And then I'll do restart
15:31:36unless stopped
15:31:40and also then we're going to do ports,
15:31:42right? So we need to do ports and this
15:31:44will be let's see. So I'm just going to
15:31:46use a different port. I'll do 6385
15:31:49and this is going to run on okay this
15:31:51will be in this. So do 63 85 and this
15:31:54will be 6379. This is the port usually
15:31:57radius runs. Save this. Now what I'm
15:32:00going to do right, we have to go to our
15:32:01env. And then I'm just going to add one
15:32:04more here and this will be my radius url
15:32:08and this will be radius and then where
15:32:11it is going to run. So it will run
15:32:13localhost colon. So you're using what?
15:32:156385 right? So 6385.
15:32:20That's it. So now what I'm going to do
15:32:22right, we'll go here and I'm just going
15:32:25to do uh I think in the package dojson
15:32:28we have doc npm or or let's directly do
15:32:30it. So do docker compose down
15:32:34and I'll do docker compose upd
15:32:40started. So let me just verify once.
15:32:42Okay. So I'll do okay. So you have
15:32:44radius this one one will be radius and
15:32:47one is postress. Fine. So I think this
15:32:49is done. So now what will be the next
15:32:51step? So next step first let's start
15:32:53with creating our cloudinary
15:32:56service right. So cloudinary helper we
15:32:58need to create and to create this one
15:32:59let's uh keep this one in leave folder.
15:33:02So I'll do leave and let's create
15:33:04cloudinary
15:33:07ts. Okay.
15:33:09All right. So first of all let's close
15:33:11everything. And this is where you are
15:33:13going to understand each and everything
15:33:15step by step. Okay. Because this is
15:33:17actually very important. So now first of
15:33:19all I'm just going to import cloudinary
15:33:25cloudinary
15:33:27from cloudinary
15:33:30and here I'm just going to take a upload
15:33:32result means the result that we are
15:33:34going to receive and this is going to
15:33:36give you two things right so one will be
15:33:38your url so this will be secure url
15:33:40which will be string and second one will
15:33:42be your public ID and this will be your
15:33:44cloudinary public ID and this also will
15:33:46be string so first will be so we are
15:33:49going to create export as sync function
15:33:52and I'm simply going to do upload banner
15:33:57image to cloudinary
15:34:01okay so now let's see how we going to do
15:34:04this so first of all what actually we
15:34:07need here now remember so we have
15:34:09covered one code module that is called
15:34:11buffer you remember so here what we
15:34:12going to use right we are going to use
15:34:14our file buffer okay so whenever we
15:34:16going to upload the image which we are
15:34:17going to receive a buffer and that
15:34:19buffer we are going to handle. So first
15:34:21of all as input we are going to receive
15:34:22a buffer. So buffer type will be buffer
15:34:26and then I'm also going to receive one
15:34:28more options and this is optional.
15:34:29Option means let's say if I go to my
15:34:31cloudinary and let's say uh I'll go to
15:34:33my assets and I wanted to create this
15:34:35particular asset inside a folder. Okay.
15:34:38And that folder name you can give here.
15:34:39I don't know why this is slow man.
15:34:46So you'll see that you have this folder
15:34:47here, right? So you can create a couple
15:34:49of folders. See, we have multiple
15:34:51folders that I have created. Correct? So
15:34:53now what I can do, right? So I can pass
15:34:55options and this option is going to
15:34:57receive one folder that in which folder
15:34:59I wanted to store this and let's keep
15:35:01this one optional. Okay. So this is the
15:35:04first thing what this is going to
15:35:05return. So this is going to return a
15:35:06promise and this is going to be my
15:35:08upload result. So I need the data in
15:35:10this particular format. So I need a URL.
15:35:12I need a public ID and this what we have
15:35:14already covered here, right? that why we
15:35:16need the URL and why we need the public
15:35:18ID. Public ID is actually very important
15:35:19because at the end this public ID is
15:35:22going to help us to identify which asset
15:35:24and then we can delete that particular
15:35:26asset from our cloudinary storage or
15:35:28whatever storage you are using doesn't
15:35:30matter. So here now I'm just going to
15:35:31take three things. So I'm just going to
15:35:33do cloud name
15:35:35and this will be my process. Again I
15:35:38already mentioned I hope that you have
15:35:39done this one. So keep this one in your
15:35:41and you can use dot like that. Okay, for
15:35:43now I'm just going to keep it like this.
15:35:45So we'll do env and then I'll do
15:35:47cloudinary cloud name. Then I'm just
15:35:49going to take con. Let's do API key. So
15:35:52this will be process
15:35:55process env dot. So you have cloudinary
15:35:58API key
15:36:00and I'll do con and this will be API
15:36:03secret and this will be process dot env
15:36:06dot cloudinary API secret. So three
15:36:09things we need. So now first of all I'm
15:36:11going to give a check that if not equal
15:36:13to cloud name or if not equals to API
15:36:17key or if not equals to API secret if
15:36:21these are not present. So in that case
15:36:22I'm going to throw a new app error. So
15:36:25I'm going to give a 500 error and I'll
15:36:27do cloudinary is not configured
15:36:28properly. So cloudinary is not
15:36:31configured properly. So this is the
15:36:34first thing and now what you can do
15:36:36right you can also I think you can
15:36:37import like this. You can also use a
15:36:39version two but for now it's fine. You
15:36:41can import like this and then what I'll
15:36:43do right. So now this is where we are
15:36:45going to do what we are going to
15:36:46configure our cloudinary because see you
15:36:48have to configure or else cloudinary
15:36:50will not understand what is your cloud
15:36:52name what is your API secret you're
15:36:55getting. So that is the reason we need
15:36:56this one or else maybe let's do this. I
15:36:58think better will be we can import
15:36:59version two and let's do this one as
15:37:01cloudinary. Okay I think this is better.
15:37:03And now I can configure this one. So how
15:37:05I'm going to configure? So do configure
15:37:07cloudinary. So I do cloudinary and if
15:37:09you do dot you'll see that you're going
15:37:11to get this config
15:37:13or sorry why cloud name I need
15:37:15cloudinary. So cloudinary doconfig and
15:37:17this is where you're going to pass all
15:37:19the three things. So you pass the cloud
15:37:21name. So this will be your cloud name.
15:37:23You have the API key and this will be
15:37:24your API key and then you have API
15:37:26secret and this will be your API secret.
15:37:30Okay. So these three things cloud cloud
15:37:32name API key and API secret. So now my
15:37:35cloud ML is configured. So what I need
15:37:37to do here see before because we are
15:37:39working with buffer you remember that
15:37:41section that how we have implemented our
15:37:44stream you remember readable stream
15:37:46writable stream transform stream all
15:37:47these things right. So what we need to
15:37:50do right whenever we are going to upload
15:37:51our image we are receiving a buffer and
15:37:54what we are going to send to cloudinary
15:37:56we are going to send our raw image bytes
15:37:58raw image bytes to cloudinary. Okay. So
15:38:01how we are going to do that? Because
15:38:02it's returning promise. So we need to
15:38:05return promise here. So I'm just going
15:38:06to do new promise. And promise is going
15:38:08to give you what? So it's going to give
15:38:10resolve and reject. Resolve and reject.
15:38:13So now first of all, so I do const. So
15:38:16we need a stream here. So we have upload
15:38:18stream. Now I'm just simply going to do
15:38:19cloudinary dot version. What I'm doing
15:38:23cloudinary dot not version
15:38:25cloudinary.uploader dot upload. And then
15:38:29you're going to get this upload stream.
15:38:31So we are uploading a stream. Now here
15:38:33what you can do right you can pass
15:38:34option and there is a call back. Now you
15:38:37see each and every module that we have
15:38:39done so far. If you have that much
15:38:40patience and completed all the section
15:38:42previously all these things would be way
15:38:45easier because now remember we have
15:38:46discussed one particular thing that what
15:38:47is our call back what is the call back
15:38:50uh format in classic nodej. So call back
15:38:53is going to give you error and it's
15:38:55going to give you a result. And now see
15:38:56this particular concept we are going to
15:38:58apply here. So what I mean by this if
15:39:00you learn those individual concepts or
15:39:02code modules properly you can combine
15:39:04all of this and you can create or use
15:39:06those concepts in a project. Okay. So
15:39:10now what I can do right I can simply
15:39:11give a resource type. So resource type
15:39:13will be I'm uploading a image here. So
15:39:15if you if you uploading image video and
15:39:17everything you can do auto or let's say
15:39:19you can if you're uploading raw give
15:39:21raw. If you're uploading video you can
15:39:22give video. We are uploading image. And
15:39:24then I'm just going to do a folder and
15:39:26folder will be my options dotfolder.
15:39:28This options dot ffolder I'm receiving
15:39:29from this option. So this is the first
15:39:31thing. Now what is this is going to
15:39:33give? So this is going to give you a
15:39:34call back. Okay. So this call back is
15:39:37now going to give you error and result.
15:39:39Okay. So this is the classic call back
15:39:42uh format. Now what [snorts] I have to
15:39:44do? So if error means what this also I
15:39:46have covered. You can't say that I
15:39:48haven't covered everything I have
15:39:49covered. So it will reject your reject
15:39:52the error and you're going to return if
15:39:54there is no error. So in that case I'm
15:39:56going to resolve. So what I'm going to
15:39:58resolve so I'm going to resolve my SQL
15:40:00URL and this URL you're going to get
15:40:02from a result and see that if I do
15:40:04result dot you're going to get
15:40:05everything. So you're going to get see
15:40:06bytes colors uh context created created
15:40:10at and here you're going to get public
15:40:13ID see and you have security URL. So I
15:40:15need this one and I need the public ID.
15:40:18So I'll do result
15:40:21dot public id.
15:40:23So these two things I need and now what
15:40:26I'm going to do right. So let me see
15:40:28where it is closing here. And this is
15:40:30where I need to do upload stream and I'm
15:40:33going to end the upload stream. So look
15:40:34dot end. And what you have to pass you
15:40:36have to pass your buffer here. Buffer is
15:40:38nothing but we are sending a raw image
15:40:40bytes to the cloud. So we're going to
15:40:42pass the buffer and this buffer we going
15:40:44to receive. Okay this one. So now we are
15:40:47sending
15:40:49uh here so we'll do sending
15:40:53raw buffer
15:40:55not raw buffer sending raw image sending
15:40:59raw image bytes to pluginary okay
15:41:03and then I think this is done we don't
15:41:05have to do anything uh okay let's see so
15:41:08we are taking this one checking
15:41:09configure returning a promise okay I
15:41:12think this is completed okay so this is
15:41:14the first thing so first helper function
15:41:16that we need. So now what we're going to
15:41:18do right so first of all we are going to
15:41:21create our routes then we're going to
15:41:23create our services create our
15:41:25repository we also going to create our
15:41:27multter middleware remember I mentioned
15:41:29that malter is a middleware that is
15:41:30going to help us to handle our multiart
15:41:32form data so we're going to create our
15:41:34multter middleware and then we're going
15:41:35to combine everything and then create
15:41:37the upload logic so let's see how we
15:41:39going to do that in the next part okay
15:41:40so now let's create all the files so
15:41:42first I'll go here and let's do admin
15:41:45dotbanners
15:41:46admin admin.banner.outes.ts.
15:41:49So this is the first one. Then go to
15:41:51repository. So I'll do admin dotbanner
15:41:54dot repository.ts
15:41:57and I'll do admin
15:42:00dotbanner
15:42:02dotservices.ts.
15:42:05So first we need to work with these
15:42:06three right. So let's start with our
15:42:08admin
15:42:10routes. So first as usual we are going
15:42:12to import something from express.
15:42:15And here we are simply going to do
15:42:19what name I'll give. So let's give
15:42:20simply export
15:42:22con and I'll do admin banner route. We
15:42:27need to import router.
15:42:30So here uh what I'm going to do right
15:42:32let's give router. So I'll do router and
15:42:34now first of all let's start with admin
15:42:36banner router. Okay let's uh do this
15:42:39also. to go to index and I'll do api
15:42:42router dot
15:42:45use / admin/banner
15:42:49banners
15:42:51uh and then we're going to do admin
15:42:53banner router save this for now so now
15:42:56what I'll do so I'll do admin router dot
15:42:58use and this I think I don't have to uh
15:43:01explain now because now we know that we
15:43:03need authenticate and require admin both
15:43:06right because this is for admin so now
15:43:08let's start with first answer admin
15:43:10route dot post
15:43:13and here what I'm going to do right now
15:43:15this is very important so I'll explain
15:43:16so first I'll do request response
15:43:21next and here first let's take a try
15:43:25catch
15:43:30so pass the error let's give error like
15:43:33this
15:43:34and here first let's create our banner
15:43:37so do banner this will be have it I'll
15:43:39do create admin banner service
15:43:45and here what you have to pass so first
15:43:48before doing this one also right so
15:43:49let's return this as usual we have done
15:43:52so now remember again here what what
15:43:54you're doing you're creating something
15:43:56correct so that means you have to use
15:43:582011 so you have to make sure all small
15:44:00small things so do success will be true
15:44:04and data you're going to return the
15:44:06banner okay So what will be next? So
15:44:09next let's create our middleware because
15:44:11as I already mentioned that we are going
15:44:12to use malter middleware to handle our
15:44:14multiart found data. So go to middleware
15:44:17and let's do here. So I'm just going to
15:44:19do banner uh dot middleware
15:44:23dot ts. So first of all we need to do
15:44:26something. We are going to import malter
15:44:27from malar because we need malar. And
15:44:30then let's take one max file size that
15:44:34what will be your file size that you
15:44:36will allow user to upload. So in this
15:44:38case I'm just going to keep let's keep
15:44:40either 5 MB or 10 MB. Let's keep 10 MB
15:44:42only. So I'll do 1024 into 1024. So this
15:44:45will be 10 MB. So now we are going to do
15:44:47export const and let's do upload banner
15:44:51image.
15:44:53So we are going to take malt and here
15:44:55you're going to pass couple of things.
15:44:57So first of all what you need right? So
15:44:58we are actually going to store our file
15:45:00in memory because at the end you will
15:45:03notice that we are actually not storing
15:45:04our file in our local right we already
15:45:06have a cloud binary cloud. So that is
15:45:08the reason we are going to simply store
15:45:10this particular file in memory and that
15:45:11is more than enough. So we are going to
15:45:14take something called storage and this
15:45:15is going to give you this multmory
15:45:18storage. Okay. Next what we going to do?
15:45:20We are going to pass a limits and in
15:45:22this limits you're going to pass a file
15:45:24size. This file size will be this max
15:45:26file size. Okay. And also [snorts] very
15:45:29very important. So what will happen,
15:45:30right? So you're going to give a file
15:45:31filter. Now this file filter is simply
15:45:34going to tell that okay what actually
15:45:36what what kind of asset you are
15:45:37uploading. So this is going to take your
15:45:40request and also you're going to pass
15:45:42our file. So you can see that we have
15:45:44the file and also it is going to give
15:45:46you a call back if I'm not wrong. Okay.
15:45:48It is going to give you call back. Okay.
15:45:50So request then you have the file and
15:45:52then it's going to give you a call back.
15:45:53So I'm just going to take call back as
15:45:55CV. Okay. Or you can take this one as
15:45:57call back also. So now what I going to
15:46:00do right here? So I'm simply going to
15:46:02check if this file not equal dot mine
15:46:06type dot starts with if this is not
15:46:09image. So in that case we will not allow
15:46:11because we only want image to be
15:46:12uploaded. So what [snorts] we going to
15:46:14do right we're going to call the call
15:46:15back and you already know the call back
15:46:16pattern. See I think I already mentioned
15:46:19this is multiple times and for this
15:46:20reason we've actually covered our core
15:46:22modules. So here what I have to pass
15:46:24we're going to pass a new app error.
15:46:25Okay. First we going to do new app
15:46:27error. Give a 400 and I'll do only image
15:46:31upload is allowed.
15:46:34Okay. And then uh don't forget to
15:46:36return. So we're going to do return. So
15:46:38now what I have to do if this is not the
15:46:40case, we're going to call the call back.
15:46:41Error will be null. And what will be
15:46:43result? Result will be true. That's it.
15:46:46Okay. And now what I'm going to do
15:46:48right, I'm simply going to do export con
15:46:51because for now we are have single uh
15:46:54image upload. So I'm just going to do
15:46:55single banner image and this will be
15:46:59your upload banner image and here you
15:47:01can do single and now this is where I'm
15:47:03going to pass a field name. Now this is
15:47:05very important. Okay, this will be your
15:47:07actual field name when you're going to
15:47:09send the request. So this is where
15:47:10you're going to pass it like this. So
15:47:12for example, let's say I wanted to pass
15:47:13like this image. So image will be my
15:47:15field name and understand when we are
15:47:16going to test it. So for now this is
15:47:18more than enough. So this is what
15:47:20actually we need. Now what will be next
15:47:22step? Next step will be first of all
15:47:23we'll go to our routes. Now this is
15:47:26where okay this will be actually
15:47:27important because we are using a
15:47:28middleware right. So what you're going
15:47:30to do before you're going to run this
15:47:31particular thing we are going to use our
15:47:33middleware. So this is where you're
15:47:34going to use this upload single banner
15:47:36image and this will be from your
15:47:38middleware. Okay. So this is done. So
15:47:40now what we're going to do right now we
15:47:42will be creating our service. So service
15:47:44what service is going to do? Service is
15:47:46going to do a couple of things. So here
15:47:47first of all we are going to check or
15:47:49give some check. Let's say if file is
15:47:51not present so it's going to return some
15:47:53error. Then it's going to upload your
15:47:55image to cloudinary. Once the upload is
15:47:57completed then what we are going to do
15:47:58then we are going to simply store that
15:48:00URL and the public ID in our uh DB.
15:48:04Okay. So that will be the overall flow.
15:48:05So now let's copy this and then let's go
15:48:07to our ad main banner service. So here
15:48:10I'm just going to do export as sync
15:48:12function and I'll do create admin banner
15:48:15service. So here you need a file. What
15:48:17will be your type? type will be your
15:48:18express dot maltter dot file or else
15:48:21this will be undefined. Okay, what this
15:48:24is going to return? So this is going to
15:48:25return a promise and here let's do one
15:48:27thing. I think we haven't created our uh
15:48:29banner type, right? So let's go to the
15:48:31types and let's create one more here. So
15:48:33I'm just going to do banner.ts.
15:48:36So I'm simply going to do [snorts]
15:48:37export type banner and this will be so
15:48:40first we need the ID. We also need our
15:48:42image URL. This will be string. We also
15:48:45need our cloudinary public ID. I think
15:48:47that is what we have taken here image
15:48:49URL and cloudinary public id this also
15:48:51will be string then you need the created
15:48:54at
15:48:56which will be what date and then you're
15:48:58going to have your updated at this also
15:49:01will be date so this will be your type
15:49:04this is what we're going to use so now
15:49:06let's go to our service so first what
15:49:08this is going to return this is going to
15:49:09return this banner type so first we have
15:49:11to check that if this file is not
15:49:13present so we are going to throw error
15:49:15so I'm just going to do throw new app
15:49:17error and here I'm going to do 400 and
15:49:20I'll do images needed or images required
15:49:22something like this so this is the first
15:49:24thing next if the file buffer is not
15:49:27present we are going to also return so
15:49:29I'll do file buffer is not present we
15:49:31are going to throw another error
15:49:34and this will be invalid image type or
15:49:36image type is invalid something like
15:49:38this
15:49:41so now what are we going to do right so
15:49:43now this is the place where we are
15:49:44actually going to upload our image to
15:49:47cloud. Remember when [snorts] you're
15:49:49going to upload the image to cloud,
15:49:50right? First you have to do it before
15:49:51you're going to set because first you'll
15:49:53upload this one to your cloud then
15:49:55you're going to get your URL back and
15:49:56then you are going to store that URL in
15:49:58your DB. Okay, so this is how it's going
15:50:00to work. So first what I'm going to do
15:50:02so I'm going to first do a and now I'm
15:50:05just going to call that upload banner
15:50:06image to cloud remember and this is
15:50:08where you're going to pass a buffer. So
15:50:10buffer will be your file dot buffer and
15:50:12then you're going to pass a folder. So
15:50:14here I'm going to pass a folder and
15:50:15let's give this one as NodeJS capstone
15:50:18project.
15:50:20So this will be my folder. What we're
15:50:22going to get we're going to get our
15:50:23secure URL and we're going to get our
15:50:24public ID. Now it makes sense, right?
15:50:26Because once we're going to upload this,
15:50:27we're going to get these two things. Now
15:50:30we're going to again we're going to
15:50:31check if this secure URL is not present
15:50:33or this public ID is not present. So
15:50:35again throw a new error. So I'll do
15:50:37throw new app error give a 500 and I'll
15:50:40do cloudinary error or something like
15:50:41this. whatever you wanted to give.
15:50:46Now what we have to do right? So now we
15:50:47already have our URL public ID. So what
15:50:49will be next step? Next step will be to
15:50:51store this one in your DB. So DB means
15:50:53now we are going to start with our
15:50:54repository. So this is where we are
15:50:56going to simply do what? So I'm just
15:50:57simply going to do con banner
15:51:01and this will have it. So I do create
15:51:03admin banner and then we are going to
15:51:06pass
15:51:08secure URL and the uh what is that
15:51:10public id these two things and at the
15:51:13end we are going to return the banner.
15:51:14Now this uh return we are going to
15:51:16return to our routes. So if you go to
15:51:19your routes where is that here we are
15:51:21going to return. Okay so now what you
15:51:23can do right so first you can import
15:51:24this one from our service and we have to
15:51:26pass our uh file. So what will be your
15:51:28file? But how we are going to get the
15:51:30file? That is the important part here.
15:51:32So you're going to get this one from
15:51:33request and this request is going to
15:51:35give you this file. Okay. So this is
15:51:36what you have to do. So now it will go
15:51:38to your service. It's going to do all
15:51:40this step. It is going to upload to
15:51:42cloudinary and then we are going to
15:51:44create this in our repository. So this
15:51:46is how it will work. So now we'll create
15:51:48copy this and go to repository and then
15:51:50I'm simply going to do export as sync
15:51:52function. [snorts]
15:51:54So create this. So here we are going to
15:51:56receive what? So what we are sending? We
15:51:58are sending the image URL which will be
15:52:00string and we're also going to get
15:52:02cloudinary public id and this will be
15:52:06your string. What this is going to
15:52:09return this is going to return a promise
15:52:10and it's going to return the banner
15:52:12type. So what I can do we can so for
15:52:15this one I think we just have to write
15:52:16simple query right. So lupool doquery
15:52:19here will be your so let's take one
15:52:22more. So I'm just going to do type
15:52:24banner row and this will be banner and
15:52:28we're going to pass this.
15:52:32Okay. So first what we have to do we
15:52:34have to insert correct.
15:52:36So do insert into so what is the name?
15:52:41So banners. So banners is the
15:52:44uh what is that table name. So do insert
15:52:46into banners. So what are you going to
15:52:48insert? We're going to insert three
15:52:49things right.
15:52:52uh image URL cloudinary public id these
15:52:55two things I think we have to do so
15:52:57let's go to our uh repository we'll do
15:53:01insert image URL and also insert the
15:53:04cloudinary
15:53:06public id
15:53:10okay and then we are going to pass the
15:53:12values so I'll do values
15:53:15so dollar one dollar2 and then we're
15:53:18going to do a returning so we're going
15:53:20to return the ID
15:53:22image URL
15:53:24cloudinary public ID
15:53:27created ad and also let's copy the
15:53:29updated ad also
15:53:35okay and then you're going to pass this
15:53:37so first what will be the first value
15:53:38first value is image URL second will be
15:53:41your cloud so here this will be image
15:53:42URL and this will be your cloud public
15:53:44ID and then you're going to just return
15:53:47result dot rows of zero and that's set.
15:53:51So save this. So this is going to save.
15:53:53Now we can simply import this from our
15:53:55repository and this is completed. So now
15:53:57before we going to test this one, right?
15:53:59So let's do one thing. Let's get all the
15:54:00banners also because then we can see
15:54:02that whether actually it is getting
15:54:03stored in our DB or not. Correct? So
15:54:05what I'm going to do, right? So let's
15:54:06create admin banner dot get. So I'm
15:54:09going to do slash and let's copy this
15:54:12from here.
15:54:18And then I'm simply going to do a try
15:54:20catch
15:54:24and I'm just going to do next error. So
15:54:27in the try so simply I'm just going to
15:54:29do con banners and this will be have it
15:54:31fetch
15:54:33admin b man b man b man b man b man b
15:54:35man b man b man b man b man banners
15:54:36and then I'm simply going to raise dot
15:54:38status of 200. I'm doing little first
15:54:40now I think we have already done so many
15:54:42times the same thing. will be success
15:54:44will be true and let's pass the data and
15:54:47data will be your manners. So now we can
15:54:49simply create this where in our service
15:54:53same thing right it's like repetative
15:54:55same thing you're going to do. So now
15:54:57let's go to our services first and then
15:55:00I'll do export as sync function and I'll
15:55:04do fetch admin banners what this is
15:55:07going to return this is going to return
15:55:08promise but remember you have to move
15:55:11all of this so it's going to return of
15:55:12array right keep because you can have
15:55:14multiple uh banners. So first what I'll
15:55:16do right so I'll do con banners this
15:55:19will be ait and I'll do find all admin
15:55:23banners
15:55:26from div something like this and then at
15:55:30the end we're going to return this
15:55:32banners so now first copy this and then
15:55:35we're going to create this one. So we'll
15:55:37go to our repository
15:55:40and I'm simply going to do export as
15:55:41sync function find on admin banners from
15:55:45DB.
15:55:47So here we are going to return promise
15:55:50of banner
15:55:54and then we are simply going to do con
15:55:57result and this will be a pull dot
15:56:00query. So this will be your banner row
15:56:04and what you going to do? So we're going
15:56:06to just select all this right. So we are
15:56:08going to do select ID
15:56:11image URL we have cloudinary
15:56:16public ID correct. So public
15:56:19id
15:56:20created at and updated at and then we're
15:56:25going to do from banners table because
15:56:27we have the banners table and let's do
15:56:30order by
15:56:32uh created
15:56:34at disk.
15:56:37That's it. And then you're simply going
15:56:38to do what? Return result
15:56:41dot rows.
15:56:44What happened man? Oh, we have to do
15:56:48outside.
15:56:49Okay, save this. So now we going to
15:56:52simply import this from here and go to
15:56:55our routes and we're going to import
15:56:57this one from our service. Save this. So
15:57:00I think this is done and I think we've
15:57:02already added it. So this one. So now
15:57:04we'll see what is actually happening.
15:57:07So let's run it again.
15:57:10Fantastic. So now I'll go here. Okay. So
15:57:14first let's open one more. So I'm just
15:57:16going to do copy this.
15:57:19So this will be post first and this will
15:57:22be admin/banners.
15:57:24Correct? And first let's go to body and
15:57:27what you have to do right you have to do
15:57:29form data. See here we have form data
15:57:31and this is the key you have to use the
15:57:32key. This key will be your image. Okay.
15:57:34This key will be the one that you are
15:57:37using here. So you have your middleware.
15:57:40See you're passing image here. Right? So
15:57:42this is your field name. So this will be
15:57:44image. Now what you have to do right you
15:57:45have to change this one to file and
15:57:47you're going to select file. Okay. So
15:57:49I'm just going to select I think I have
15:57:51downloaded one simple uh which one I can
15:57:55use man. Maybe I think I also have some
15:57:57thumbnails designed.
15:58:00Okay. Let's do this one. Okay. So I'm
15:58:02just going to select this one. So first
15:58:04let's try to send access token is
15:58:07needed. Fantastic. So we'll go to this
15:58:10one. So let's uh log in or maybe first
15:58:13I'm going to check. So I'll do sum get
15:58:16the token copy this
15:58:19and then I'll go to headers add
15:58:21authorization
15:58:24and I'll do b error
15:58:26and you'll see that you're going going
15:58:28to get admin access is required.
15:58:30Awesome. So that means you have to use
15:58:32admin token send.
15:58:35Uh we'll copy this. Go here. go to
15:58:39headers. So we'll do be error
15:58:43and then try to send. All right. So
15:58:46happening. So let's see what is
15:58:47happening. That's it. So now you have ID
15:58:50image URL cloudinary public ID are
15:58:52getting created at updated. Now let's go
15:58:55here and I'll go to my assets.
15:59:00That's it. So you have your image here.
15:59:02So that [snorts] means this image is now
15:59:04already added here. And at the same time
15:59:06you are getting the uh URL and this URL
15:59:08you are now saving in your DV. So now
15:59:10let's say if I just wanted to copy this
15:59:12and if I go here and uh this one or
15:59:15let's do one thing. I'm also going to
15:59:17add one more. Okay. So I'm just going to
15:59:19close this and add one more here. Maybe
15:59:21I'll just do this one advanc type script
15:59:25and then I'll just send.
15:59:31So this is done. So now let's go here.
15:59:33Refresh this.
15:59:35Save two. And maybe let's do one more
15:59:38because we need this one. You will
15:59:40understand why I'm doing this. I will
15:59:42use this one.
15:59:50So this is done also. Let's check once.
15:59:53Okay. So this is added now. So now what
15:59:56we can do, right, we can go here and
15:59:57first I'll go here. Go to headers. I'll
16:00:00copy this entire part and then go to
16:00:02headers, add authorization
16:00:05and paste this one. Try to send and you
16:00:08can see that you already have banners 1
16:00:102 and three. Fantastic. That's it. So
16:00:13that means now what you can do right you
16:00:15are actually fetching the banners
16:00:17directly from your DB. You don't have to
16:00:19interact with your cloud now because
16:00:20you're already storing your assets in
16:00:22your cloud. But the main point will come
16:00:24that when you're going to delete this
16:00:25one, right? So you just can't directly
16:00:28delete from your DV. you also have to
16:00:29delete this one from your cloud. So this
16:00:32one you're going to do in the next part.
16:00:33All right. So now let's implement some
16:00:35caching uh strategy. So what are you
16:00:38going to do right? So where I'm going to
16:00:39implement caching. So let me show you
16:00:41and I'm just going to close those files
16:00:43that are not needed. So you see that
16:00:45we're feting the admin banners right. So
16:00:47what you're going to do right every time
16:00:48we are not going to f directly from our
16:00:50DB. I think you have already checked
16:00:52this one in the radius section. I hope
16:00:53that you have covered this one. So what
16:00:55you're going to do right? So if I'm not
16:00:57wrong, let me just quickly check. That
16:00:58is called the cast aside pattern, right?
16:01:00So we have the cash
16:01:03aside
16:01:04pattern.
16:01:06I think it's called cash aside only.
16:01:11Uh okay, let me just check what is that
16:01:13called. Citiz
16:01:22going to record database immediately
16:01:24save the result. Okay. So this is what
16:01:25actually we we need. Okay. So we're
16:01:27going to implement right. So if the data
16:01:29is already present in the cache. So in
16:01:31that case we are not going to fetch from
16:01:33our DV or else we are going to fetch
16:01:36from our DV. But before that we also
16:01:37have to do couple of things. So first
16:01:39what we going to do right? We'll go to
16:01:40our leave
16:01:43folder and then I'm just going to create
16:01:44a radius. TS file. And now first of all
16:01:47what I'm going to do right also let's do
16:01:49one thing. So let's add our radius curl
16:01:52also here. So I'll do rad CL.
16:01:55So this will be check required NV
16:01:58variables and go to our env. And then we
16:02:01going to do radius CL.
16:02:04Save this. So now first of all what I'll
16:02:06do right I'm simply going to import
16:02:09radius from my radius. So this is the
16:02:12first thing and then I'm simply going to
16:02:14do export const. So I'll do radius and
16:02:16this will be so I'll do new radius and
16:02:20here we going to pass env
16:02:22dot radius url. Now because we using
16:02:26bool uh sorry we are using bool mq
16:02:29right. So for bool mq when we are going
16:02:30to implement our background job and
16:02:32background worker
16:02:33bool [snorts] mq actually needs its own
16:02:36connection request okay or own
16:02:38connection request opsense object. So in
16:02:41that case what we going to do right we
16:02:42not going to pass our IO radius
16:02:44instance. Okay. So what we going to do
16:02:46right we are simply going to do con and
16:02:49then I'm simply going going to do a
16:02:50radius URL and this will be new and here
16:02:53we're going to use the URL and here we
16:02:56going to pass the env dot radius URL.
16:02:58Okay. So that means we're creating what
16:03:00we are creating here our own connection
16:03:03object request and then what you can do
16:03:05right we are simply going to do export
16:03:07con and here you can do bull
16:03:10uh mq connection
16:03:14and this will be you have to pass a
16:03:16host. So host will be your radius url
16:03:19dot host name. This part also you have
16:03:21covered in the URL code modules in the
16:03:23NodeJS code modules on this port you're
16:03:25simply going to get your number and
16:03:27you'll get is radius URL and this is
16:03:30going to give you the port okay and then
16:03:32we are also going to take let's take a
16:03:34max uh retries max retries per request
16:03:42and this will be null for no okay so
16:03:44save this so first before we'll
16:03:46implement our background job logic what
16:03:49are going to do right so Let's implement
16:03:50our banner cache. So let's do this one
16:03:53in leave only. So I'm just going to uh
16:03:56do here banner cache
16:03:59dot yes. So first of all what we are
16:04:01going to do. So first here uh also we
16:04:04need to do couple of things. If you have
16:04:06already covered the uh ready section we
16:04:08know that we actually need two things.
16:04:10We need the cast key right and that cast
16:04:13key will be using that cast key will be
16:04:15able to identify. Second we need a TTL.
16:04:17Correct? So this is what you're going to
16:04:19do. So, I'm just going to do a const and
16:04:21let's do admin banners
16:04:24cask key. You can always uh make sure to
16:04:27move all of this in your uh what is that
16:04:29called? Uh
16:04:31uh constant file. So, admin banners also
16:04:34I need con and I'll do admin banners
16:04:38cash
16:04:40t seconds and this will be 60. So, this
16:04:46is the first thing. So, now we are going
16:04:48to create our cash. So first we are
16:04:49going to create how many methods you
16:04:51need. So first of all one will be to
16:04:54check that whether the cache is present
16:04:56or not because if the cash data is
16:04:57present we going to return from the
16:04:59cache. Second we need to set the data in
16:05:02our cache and third will be to
16:05:04invalidate the cache. Remember
16:05:05invalidate technique I mentioned. So
16:05:07let's say you have two assets added or
16:05:09two images added in your cloudinary and
16:05:11you already storing in your cash. Now
16:05:13next time when you're going to add a new
16:05:14asset so now the number will become 2 to
16:05:17three. So if you're not invalidating
16:05:18your cash, you are always going to
16:05:20receive two data until unless the TTL
16:05:22expires. Okay. So that is the reason you
16:05:24need uh that clear method also. So I'm
16:05:28simply going to do function and here I'm
16:05:30simply going to do get banners from gas.
16:05:34So what this is going to return? So this
16:05:36is going to return a promise and the
16:05:38type will be what it's going to return
16:05:40banner of because it there can be
16:05:43multiple banners. So here I'm simply
16:05:45going to do con
16:05:48data and this will be a so we're going
16:05:51to use radius from radius and this is
16:05:54going to do get method and this get
16:05:56method what you have to pass you have to
16:05:57pass the cast key right that's it and if
16:06:00this data is not present so what you're
16:06:02going to do you're going to return null
16:06:06and if this data is present so you're
16:06:07going to do a JSON doparts it's like
16:06:09simple and then you're going to do what
16:06:11cache data and what will be the type
16:06:13will be as banner of array. So this will
16:06:16simply get the data from your C. You
16:06:18don't have to do anything. Next I have
16:06:21to set. So I'll do export as sync
16:06:23function and I'll do set banner C. This
16:06:28also what? So it's going to return the
16:06:29banners data. The type will be banner of
16:06:32array and this is not going to return
16:06:35anything because we don't have to do
16:06:36anything here. We're just going to set
16:06:38what you're going to set. So a radius we
16:06:40have a set method. So you're going to
16:06:42set what this is going to receive. This
16:06:44is going to receive your key. So this
16:06:45will be your admin b maners cast key.
16:06:48Then you're going to set the data the
16:06:50value. So what will be the value? Value
16:06:52will be JSON dot stringify the banners
16:06:55data.
16:06:57So this banners data that you're going
16:06:58to receive. And then uh we are also
16:07:01going to pass. So let's pass a x and
16:07:04then I'm also going to pass the ttl. TTL
16:07:07will be my TTL.
16:07:09Save. I think this is done. And then
16:07:12last we need to validate invalidate. So
16:07:14do export as sync function
16:07:16and I do look clear banners
16:07:21and this will be promise of
16:07:26void. So what are we going to do here?
16:07:28We're simply going to do a radius dot
16:07:31delete and you're going to pass the cask
16:07:33key. That's it. So these three you need.
16:07:36Now how you're going to use this? This
16:07:37is the important part right. So where
16:07:39you are going to use this one or first
16:07:41of all where you are going to set and
16:07:43when you're going to delete or when
16:07:45you're going to receive. So you have to
16:07:46do all this in your service. The first
16:07:49one very very important when you're
16:07:50going to create a new asset. So whenever
16:07:53we are going to create a new asset let's
16:07:55say this one after this we need to
16:07:57invalidate the cash and I think this one
16:08:00you're clearly understanding why we are
16:08:01doing right. So every time you're going
16:08:02to do we need to do what? We're going to
16:08:04do a and we're going to do clear
16:08:08dash banners cash. So this is the first
16:08:11thing. Okay. Now next will be how you're
16:08:14going to fetch. Now fetch is actually
16:08:15very simple. So first what you'll do? So
16:08:17we're going to do con
16:08:19do get cast banners. See radius is not
16:08:24that much difficult. Okay. If you
16:08:25practice you will be able to understand
16:08:27very easily. And I'm simply going to do
16:08:28get banners from cast. And then we'll
16:08:31check if this get banner from cash is
16:08:34present. You simply return this data. So
16:08:36you're going to return oh sorry get cash
16:08:39banners present you return this. If this
16:08:42is not so you're going to fetch from
16:08:43your DB. So you already have this one
16:08:45from DB and then you're going to just
16:08:47set the data to cache
16:08:50because if your data is already present
16:08:52is cast you don't have to set it
16:08:54correct. If it is not then you're going
16:08:55to set. So here you're going to do a do
16:08:58set banner cast and you're going to pass
16:09:01these banners. That's it. And this is
16:09:03done. So now what will happen right? So
16:09:05now this radius functionality should
16:09:07work. So every time so let's say if I
16:09:09try to send this right and next time I'm
16:09:11going to send now see the timing here.
16:09:13So it's actually receiving from the
16:09:15cash. Okay. So it's actually receiving
16:09:17from your cash very very clearly. You
16:09:19can see this one right? So also you can
16:09:21also verify. Let's say if I try to I'm
16:09:24not sure if this will work. So let's do
16:09:26one thing. Let's try to check. So I'm
16:09:28just going to remove this clear banner
16:09:30cast. Okay. And I'll go here. And then
16:09:33let's say if I try to send this one.
16:09:38So this is now done. And then let's see
16:09:41what you're getting.
16:09:43So you can see that you are getting 1 2
16:09:453. Three only. But if you go here, you
16:09:48see that you have one more here.
16:09:511 2 3 4. So you're getting only three
16:09:53because you are not clearing the cash.
16:09:55But now if I remove this right and next
16:09:57time let's say better wait to send I'll
16:09:59see that you should be getting. So you
16:10:00are still getting three only here.
16:10:08Okay I have to create I got it. So I
16:10:10have to create here one more. So then it
16:10:12will be cleared. My bad. So now once I
16:10:14create uh clear uh sorry clear right and
16:10:16if I go here now try to send. So you'll
16:10:18be getting five. I see that 1 2 3 4 5
16:10:23simple. So that means when we'll create
16:10:26that time we're going to clear the
16:10:27cache. So with this now caching is also
16:10:30completed. Now try to implement some of
16:10:32the caching in other parts if you want
16:10:34like in the CL in the previous sections.
16:10:36So now what we have to do we are going
16:10:37to do very very important section which
16:10:38will be how we going to delete. So in
16:10:40this case we're going to use bool MQ and
16:10:42we are going to implement our background
16:10:44job and background worker. So let's see
16:10:45how we going to do that in the next
16:10:46part. All right. So now this one will be
16:10:48very very important section. Okay. So in
16:10:50this one you are going to understand
16:10:51that how we are going to implement a
16:10:53background job feature. So whenever we
16:10:55are going to delete a image from our
16:10:56cloudinary. So how we are going to
16:10:58delete from DB and at the same time the
16:11:00delete from cloud or delete from your
16:11:02cloudinary will happen in the
16:11:04background. Okay. So we are going to
16:11:06return our response immediately but in
16:11:08the background bool MQ and radius is
16:11:10going to take care of deleting these
16:11:12assets. Okay. So first let's do one by
16:11:14one. Okay. And this will be very very
16:11:16interesting because you need to
16:11:17understand the flow first. So go to
16:11:19[snorts] leave and cloudinary and we
16:11:20need one more helper function here and
16:11:22that will be to delete. Okay. So first
16:11:24I'm just going to do export as sync
16:11:26function and this will be my delete
16:11:30banner image from cloudinary.
16:11:37So first of all what we need we need
16:11:39public ID. I think I don't have to
16:11:40explain I already mentioned this one
16:11:42multiple times that that is the reason
16:11:45we are actually keeping the public ID
16:11:47because this will help us to delete this
16:11:49one from cloudinary
16:11:52so we'll do void and now
16:11:56let's take these two uh let's take this
16:11:59line and then we are also going to I
16:12:00think we can take this part
16:12:06this will be same so we paste this one
16:12:08and Now we can simply do return. So
16:12:11we'll have cloudy dot uploader and then
16:12:14you have something called destroy and
16:12:16then you're simply going to do public
16:12:17ID. Now this cloud is going to take care
16:12:20of that particular asset deletion based
16:12:22on the public ID and it's going to
16:12:23delete from here. Okay. So this is the
16:12:25first thing. So now what you're going to
16:12:27do right? So first okay we also need to
16:12:30do one uh important thing and that is we
16:12:32are going to create one more route here.
16:12:34Correct. So let's go to routes admin
16:12:36banner routes and let's create our route
16:12:38here. So admin banner route dot delete
16:12:41and here I'm simply going to do banner
16:12:43ID. Why? Because you need the dynamic
16:12:45value because you need to understand
16:12:46that which banner you're going to
16:12:48delete. Correct? So here
16:12:52so this will be next.
16:12:54And now I'm simply going to do try catch
16:12:58and in this catch you're going to take
16:13:00error. And now we're going to do next.
16:13:03And then you're going to pass the error.
16:13:04Okay. Now this one I think we have
16:13:06already covered why we are doing the
16:13:07same thing so that it will be uniform.
16:13:08But you can do lot of other way also
16:13:10here. Okay. So but this is fine. So here
16:13:13what we're going to do. First we're
16:13:14going to call a service. Okay. This
16:13:16service will be delete admin banner
16:13:19service. Now let's understand this flow
16:13:21one by one. What you're going to pass?
16:13:23You're going to pass a request dot
16:13:25params and then banner ID. Simple. So
16:13:27you're going to get the banner ID.
16:13:28That's it. And then you're going to
16:13:30return a response. So raise dot status
16:13:32200 dot JSON. And now you're going to do
16:13:36success will be true. And let's do
16:13:39message.
16:13:41So this will be banner deleted
16:13:44successfully.
16:13:47What? Okay. So this will be banner
16:13:50deleted successfully.
16:13:54Okay. But what will be in this service?
16:13:57Now this is where it will be very
16:13:58important. Okay. So this is where you
16:14:00have to understand that how this will
16:14:01work. If you do this one properly one
16:14:05you'll be able to create multiple. Okay.
16:14:07So if you go to service and let's create
16:14:10this service. So first of all I'm just
16:14:11going to do export as sync function and
16:14:14we have got a delete what is it? Delete
16:14:16admin banner. What this is going to
16:14:18receive? This is going to receive a
16:14:19banner ID. This will be a string. What
16:14:23this is going to return nothing. So it's
16:14:24going to return promise and then void.
16:14:26So now you have to understand the flow
16:14:28here. Now what I mean by flow. So first
16:14:31as I already mentioned that when we
16:14:32going to delete we are going to delete
16:14:34from your DB immediately. We are going
16:14:37to delete from our postgress first and
16:14:39we are going to get our cloud. So do
16:14:41delete from our DB
16:14:44and get the and get the public
16:14:50ID. So now I'm simply going to do con
16:14:52public ID. This will be a delete
16:14:57admin banner by id. How you going to
16:15:01get? We're going to pass the banner ID.
16:15:03Okay. So then I'm simply going to check
16:15:05if this public ID is not present. So
16:15:08I'll do throw new app error 404 and I'll
16:15:12do banner not found. And now what I have
16:15:16to do here can you guess this one we're
16:15:19going to create. So this we just have to
16:15:20delete from our posgress DB. Now once
16:15:24you delete then what you have to do see
16:15:26remember let's say you have a five
16:15:27assets added correct once you delete one
16:15:30asset it will become four now let's say
16:15:32those five assets assets are stored in
16:15:35your radius cache so that means when
16:15:37you're going to delete so now your DB
16:15:39becomes four next time when when you're
16:15:41going to fetch we are going to get four
16:15:43data correct but if you're not
16:15:46invalidating your cast you are always
16:15:48going to get five data that we have
16:15:50checked this one so that means here also
16:15:51you're going to do private clear better
16:15:54case now this is extremely important
16:15:56okay very important now why I'm
16:15:57repeating this thing very important and
16:16:00I'm telling this one same thing again
16:16:01and again because when you're
16:16:03implementing radius and all you need to
16:16:04know where you are going to use this
16:16:06radius
16:16:07methods right you can't just like
16:16:10blindly use this based on the feature
16:16:11you have to use for example here we are
16:16:13using maybe in some other functionality
16:16:15we don't have to use this one so you you
16:16:16have to understand no one is going to
16:16:18come and teach you in every project okay
16:16:20so now what you have to do
16:16:22This is where we're going to add our BMQ
16:16:24job. So I'll do add MQ.
16:16:28So this is going to happen in the
16:16:29background. So first we're going to
16:16:31delete from our posgress get the public
16:16:32ID and then add this one to our
16:16:34background job. But before this first
16:16:37let's delete this one from our DB. So
16:16:38I'll go to our repository and let's
16:16:42create one more. So I'll do export async
16:16:45function. See night time also this uh
16:16:49bikes and everything right? sound. Okay.
16:16:52So you'll see banner ID we are going to
16:16:54get this will be string and what this is
16:16:57going to return. So this is going to
16:16:58return a promise. Let's do whether it's
16:17:00return string or null because we are
16:17:02going to return the uh what is that?
16:17:05What is that called? Public id. So we do
16:17:08con result. So do ait cool dot query.
16:17:14So this is going to give you the
16:17:15cloudinary
16:17:18public ID. you can directly directly
16:17:20take here only and this will be a string
16:17:23and here what I'm going to do oh
16:17:27here we are going to write our qu so now
16:17:29I'm simply going to do that delete from
16:17:34what what is the name banners where id
16:17:38equal to 1 and then I'm going to return
16:17:42so I'll do returning cloudinary public
16:17:44ID because see we at the end we are
16:17:47going to have the cloudinary public ID
16:17:49here. Correct? And then you're going to
16:17:50pass your value which will be your
16:17:52banner ID. And now what are we going to
16:17:55do? So do return
16:17:58result dot rows of zero
16:18:03dot cloud public ID or else this will be
16:18:06null. So this is going to delete from
16:18:08your DB. It's going to return the public
16:18:10ID. Now we are going to add this one to
16:18:12our boolean key job. So I'm going to add
16:18:14it. We'll do add delete
16:18:18cloudinary
16:18:21B uh let's do cloudinary image job
16:18:25and this will be public ID.
16:18:29So first let's import this from our
16:18:31repository. So we're going to copy this.
16:18:33Now let's create our Q. Okay. So here we
16:18:35are going to create our Q's. So we're
16:18:37going to create Q's and workers. So I'm
16:18:39going to add a Q here. Okay. And let's
16:18:42give this one name as delete
16:18:44cloudinary. No, let's keep this one
16:18:46capsule cloudinary
16:18:50image
16:18:52dot q
16:18:55not this much dot q.ts.
16:18:58Okay. So now here we are going to first
16:19:02of all we have to take our q name. So
16:19:05I'll do a Q name and this will be your
16:19:08cloudinary
16:19:11jobs. So this will be your preview name
16:19:13for handling audio cloudinary related
16:19:16job. So first what I'm going to do right
16:19:18I'm going to do export as sync function
16:19:21and I'll do add delete
16:19:24cloudinary image job. What this is going
16:19:27to receive? So let's import this one
16:19:30from our job. So this is going to
16:19:32receive a public ID. Correct? So here
16:19:34you're going to receive [snorts] a
16:19:35public id and this public id will be
16:19:38string and here we're going to return a
16:19:40promise of
16:19:43void. So now what are we going to do
16:19:46first? So first of all let's do one
16:19:48thing what you have to do right. So we
16:19:50are going to add one job. So this is
16:19:51what we're going to do. We going to add
16:19:53one job to our que. Okay. So there will
16:19:58be two things. So first will be your
16:19:59job.name mean this is going to tell that
16:20:01okay what kind of job you are going to
16:20:03do. Second there will be data means the
16:20:05data that you need to pass to your
16:20:08worker. So you have a Q and then you're
16:20:10going to have a worker two things. Okay.
16:20:12So first what I'll do right? So let's do
16:20:14Q and then I'm simply going to do type.
16:20:17So I'm just going to do a delete
16:20:20cloudinary
16:20:22image job data and here I'm simply going
16:20:26to have a public ID. Correct? So do
16:20:28public ID and this will be string.
16:20:31So now what I'll do right? So first I'm
16:20:32going to do con this will be my job data
16:20:36and this will be my this one uh delete
16:20:38cloudinary job data and this is where
16:20:40you're going to have your public ID all
16:20:41right and this public ID is the public
16:20:43ID that you're receiving so now we are
16:20:45going to add our job to our que how you
16:20:47can do that so I'm just going to add it
16:20:50and here we are going to create a que so
16:20:53how you're going to create a que to
16:20:54create a simply going to do const and
16:20:57you do delete cloudinary image q and
16:21:01this will be a new Q from BM MQ you're
16:21:05going to import you have to pass the
16:21:07name right and then you have see you
16:21:09have a connection type of radius
16:21:11connection correct so you need the
16:21:12radius connection so here you're going
16:21:13to pass a Q name and your connection
16:21:15will be your B MQ connection that you
16:21:18have created remember in the radius here
16:21:20host port and max retries per request so
16:21:23this is going to create a Q and this Q
16:21:25[snorts] you're going to add here so I'm
16:21:27just going to this dot add and now
16:21:30you're going to pass that what will be
16:21:32name and what will be data data will be
16:21:34that what data sorry what work you are
16:21:36actually doing so what we we are doing
16:21:38here we actually doing a deleting right
16:21:40so what you can do right you can create
16:21:42one more con here and I'm simply going
16:21:44to do delete
16:21:46cloudinary
16:21:48image job and this will be uh delete
16:21:56cloudinary
16:21:58image so this would be my job Right. So
16:22:01this is what we are doing here. So I'm
16:22:03going to pass this job and then you're
16:22:04going to pass the job data. So job data
16:22:06will be your public ID. This will be
16:22:08your job data and then you can pass
16:22:11couple of properties. So first one will
16:22:12be let's try attempts. So three times we
16:22:14are going to check. Let's add some back
16:22:17off. So here I'm just going to do type
16:22:18and this will be exponential and let's
16:22:21do a delay of 3,000. Right? So what will
16:22:25happen if this fails by any chance?
16:22:27Sorry. Oh not this one. If cloudinary
16:22:30fails. So what we're going to do we're
16:22:31going to retrace automatically and also
16:22:33let's do one thing. So what we're going
16:22:34to do right we're going to keep our
16:22:36radius connection clean once it is done.
16:22:38So we'll do remove on complete. So this
16:22:40will be true and let's do remove on
16:22:43fail. This will be false.
16:22:45So this will be our job that we are
16:22:48going to do. So simply important thing
16:22:49you have to understand that what data
16:22:50you are sending. So we are sending our
16:22:52job data which receives the public ID.
16:22:55What will be your job right? What
16:22:57actually you're doing that you have to
16:22:59explain right? And then how we going to
16:23:00create the latest connection. So now we
16:23:03can save this. Now this is not yet
16:23:05completed. Why? Because you need to
16:23:06create the worker. Worker is going to
16:23:09actually do the things right. So it's
16:23:10going to delete your image. How it's
16:23:13going to delete your image? Because if
16:23:14you go to your cloudinary what we are
16:23:16doing here. Okay. Let's import this one
16:23:19here. So if you go to your cloudinary uh
16:23:23here, right? So we have this delete
16:23:25image from cloudinary. This one we are
16:23:27not using any place. See we have only
16:23:29one place. So this is what we going to
16:23:31use in our worker and this is where
16:23:33actually we are returning or actually we
16:23:35are deleting the asset. So let's see how
16:23:37you're going to do that in the worker
16:23:38part. Okay. So now let's go to our
16:23:40source and let's create our workers. So
16:23:43here we are going to do delete
16:23:47plinary
16:23:49image dotworker
16:23:52ds. So first what you have to do right
16:23:55uh let's close everything else. We need
16:23:57our Q's. Let's go to Q's file. And we
16:24:01need the Q name. Now this Q name has to
16:24:03be same. Okay. The the Q name that
16:24:05you're using in Q and the Q name you're
16:24:07using in worker both has to be same. So
16:24:10now what also let's take this also
16:24:12because we have this type delete
16:24:14cloudinary image job data. This is also
16:24:16we need the public ID.
16:24:18So first let's create our export con and
16:24:21this will be our delete cloudinary
16:24:24image worker. Here
16:24:28what you're going to do right we're
16:24:29going to import new worker from our
16:24:32boolean MQ. So this will be from your
16:24:34boolean MQ what you need? So first of
16:24:36all you need see you need the name. Okay
16:24:38so this will be the Q name and then
16:24:40you're going to do what? It's going we
16:24:42are going to create one async job in
16:24:45this. So first I'm going to do a Q name
16:24:47and then I'm going to take async
16:24:49function and this is will be our job. So
16:24:52first what I'll do right simply I'm
16:24:54going to check if this job dot name if
16:24:57this not equal to this delete I think
16:25:00let's create this one where is that
16:25:02delete uh uh this one delete cloudinary
16:25:06image job both has to be same also so if
16:25:09this is not the case so in that case
16:25:13what I'll do we're going to return so
16:25:14this is the first thing and then what I
16:25:16going to do I'll do con data and this
16:25:19will be my job dot data
16:25:21as so what you're sending here so you're
16:25:24sending in the data right in the data
16:25:26you're sending public ID correct this
16:25:28job data so that means this will be the
16:25:30this type that you're using so you're
16:25:32receiving public ID so this will be as
16:25:34delete cloudinary image job data and now
16:25:36what you're going to do you'll do a and
16:25:38this is where you're going to do delete
16:25:40banner image from cloudinary
16:25:43now here this is where you are actually
16:25:46going to delete this one so that means
16:25:47this is the place we are actually
16:25:49calling this delete function which is
16:25:51actually going to delete the asset from
16:25:53your uh cloud ID. Now this one you see
16:25:56that we are not doing in our route we
16:25:58are doing in the background. Okay. So
16:25:59this is what you're going to do and then
16:26:00pass the public ID. What will be public
16:26:03ID? Public ID will be data dot public
16:26:05ID. That's it. So this is done and then
16:26:08what you're going to do right you have
16:26:09to pass a connection here also. If I go
16:26:10over here right so you see that uh we
16:26:13have the worker see we have to pass the
16:26:15worker option and the connection also.
16:26:16So here we have to do what right? We're
16:26:18going to pass a connection and this
16:26:20connection will be your BMQ
16:26:23connection. So this is done but this is
16:26:25not yet completed. Now what we're going
16:26:27to do right we're going to call this
16:26:28delete uh cloudinate image worker and
16:26:30we're going to take a on event and this
16:26:32will be once this is completed. So you
16:26:34see that once this is completed so what
16:26:36we're going to do right we're going to
16:26:38do something. So let's say I'm going to
16:26:40log some data here. So what I'll do
16:26:42right, I'm going to take our logger doin
16:26:44info and I'm simply going to do
16:26:47cloudinary
16:26:50delete job completed. Okay. And uh let's
16:26:56do assets removed something like this.
16:26:59Now let's give a completed.
16:27:03And here we are going to do this. Let's
16:27:04do job do ID. So this will be when this
16:27:08is completed. if this is failed. So I'm
16:27:10just going to do cloudinary sorry delete
16:27:13cloudinary worker dot on and this will
16:27:16be when this is failed. So in this case
16:27:19we're going to get uh error also right?
16:27:22So we have a failed so we have error
16:27:23also. So in this case we're going to get
16:27:24a job and error. So in this case I'm
16:27:27simply going to do logger dot error.
16:27:30So let's pass error. So this will be an
16:27:34error and I'm simply going to pass a job
16:27:37id which will be job dot id
16:27:41and I'm simply going to do cloudinary
16:27:47delete
16:27:48job field and then at the end we're
16:27:52going to do a log.info and I'll do
16:27:55delete cloudinary
16:27:58image worker started.
16:28:02So this is done but this is still not
16:28:05yet completed. What we are going to do
16:28:06right go to package dojson and then we
16:28:10are going to add one more script here.
16:28:12So I'm simply going to do a worker and
16:28:15also do tsx source/
16:28:18So we have workers right? So we have
16:28:20workers and then let's run uh copy this.
16:28:24So do workers/
16:28:26this. So now what we'll do right we'll
16:28:29go here open one more and I'm just going
16:28:32to do npm run
16:28:34worker.
16:28:37So this is started now see so first
16:28:40we'll go here and then first let's do
16:28:43one thing let's go to our login right.
16:28:45So I'm just going to go to login.
16:28:48Let's take create one uh token. We'll
16:28:52copy this. We'll go here. We'll change
16:28:54this one to delete. And then uh what
16:28:57also you're going to do first also let's
16:28:59see one thing man. Okay, let's go to our
16:29:02uh where is that? Uh routes.
16:29:05Okay, we're using delete. That's fine.
16:29:07So, we'll do banners slash and let's say
16:29:09I wanted to delete which one we wanted
16:29:12to delete. Maybe let's check this image,
16:29:14right? So, I wanted to check this image
16:29:15backend system and maybe I wanted to
16:29:17delete this one. So, what I'll do right,
16:29:19I'm going to take the ID
16:29:22and then I'm going to paste it here. Go
16:29:24to headers, add authorization,
16:29:27and then I'm going to take the token.
16:29:36Okay. And then I'll just add it here. So
16:29:38do beer
16:29:41space and see what will happen. Now I
16:29:43wanted to wait. I wanted to keep this
16:29:46one open. So you'll see that this is
16:29:49started. Now I'm just going to delete
16:29:50send this. Delete it successfully. And
16:29:52you'll see that cloudinary delete job
16:29:54completed one immediately. Now if you go
16:29:56here we have four and refresh this.
16:30:00That's it. And you'll see that uh I
16:30:03think we have added four rightes. Okay
16:30:05let's do one thing. I think let's delete
16:30:09uh I think that is the reason I should
16:30:10should not have added all of these here
16:30:12man. So maybe what I'm going to do
16:30:14right. Okay I'll do a different way. So
16:30:16first I'll go to I'll copy this. Okay
16:30:19I'll copy this. Let's go to post. I'll
16:30:21add one more here. So, paste this one.
16:30:24Go to body and let's close this and
16:30:27select a different one. Maybe let's add
16:30:29this one. And then I'm going to send
16:30:31this one.
16:30:36Okay. This is done. Let's go here,
16:30:38refresh this.
16:30:41Okay. So, we have this one correct. Now,
16:30:43what I'll do, right, I will copy this
16:30:45ID.
16:30:46Go to delete. And you'll see that we
16:30:48have this one open. Okay. So, one job is
16:30:50completed. And now I'm going to just
16:30:52paste this one here. Delete this.
16:30:55Immediately deleted. And you see
16:30:57cloudinary delete job. See how fast this
16:30:59is. Okay. Crazy. So this is already
16:31:02deleted. And if you go here, you don't
16:31:05have that image. That's it. So that
16:31:07means this is how you're going to
16:31:08implement background fe uh background
16:31:10jobs. Okay. So you're going to have a
16:31:11queue. You're going to have a worker.
16:31:13The important part is that you have to
16:31:15understand that how when you're going to
16:31:16add the job in your queue because we
16:31:19have added this one where in our
16:31:20services correct this is where we are
16:31:21adding this one and then your worker is
16:31:23going to pick it up and based on that
16:31:25he's going to do the job in the
16:31:26background so with this now this
16:31:28particular section is completed okay all
16:31:31right so now what will be our next step
16:31:33next step now we are going to implement
16:31:34our Google o login so first of all see I
16:31:38think some of you already have seen in
16:31:39some other website that whenever you
16:31:41you'll go to their login page or signup
16:31:43pages. See that you're going to have
16:31:45[snorts] like uh consider like you're
16:31:47going to have that you sign in with
16:31:50email or password or you just sign in
16:31:53with Google directly. So how this
16:31:56particular flow work? Now see I'm not
16:31:57going to go into too much technical but
16:31:59I will try to explain this flow in very
16:32:01very simpler way. So what usually happen
16:32:03let's see if you have I think some I'm
16:32:05pretty much sure almost all of you have
16:32:08seen this particular flow that whenever
16:32:10you click on this Google button or
16:32:12whatever it is there let's say link
16:32:14you'll see that it will go to a Google
16:32:16login page correct and that makes sense
16:32:18because we are actually doing the login
16:32:20using Google and it's the task of Google
16:32:22who is going to actually do the
16:32:23verification
16:32:25whether this particular user is a valid
16:32:27Google user or not. So in that case what
16:32:29you have to do right we don't have to
16:32:30again manage our password in this case
16:32:33because Google is already taking care of
16:32:34all of this. So how this flow will work.
16:32:37So let's say so first of all you are
16:32:39going to have your application right and
16:32:41in this application you're going to have
16:32:42a button right? So let's say continue
16:32:44with Google once you're going to click
16:32:45on Google right. So what will happen
16:32:47right? So we are going to create a
16:32:48Google project for this. First of all we
16:32:50need some Google credentials. Why?
16:32:52because to navigate that particular user
16:32:54from your application to the Google
16:32:56login page, you need to configure
16:32:58something in your application and that
16:33:00is called we need two things. So first
16:33:02of all you need actually three things we
16:33:04need uh one Google cloud project which
16:33:06is going to give you the Google client
16:33:08ID and client secret and then it's also
16:33:11going to give you something called
16:33:12redirect URL. But why actually we need
16:33:14Google client and Google secret. So
16:33:16first of all what are you going to do
16:33:17right? we need to create a new Google
16:33:18instance using that client ID and client
16:33:21secret and then once user is going to
16:33:23click on this particular button. So now
16:33:25we are going to use some packages or you
16:33:27can directly use that URL also. So what
16:33:28will happen? It will navigate this
16:33:30particular user to the Google login
16:33:32page. So that will be the first step and
16:33:34then in the Google login page what we
16:33:36are going to do right. So normally we
16:33:37are going to create here uh that uh
16:33:40something called we have a uh concept
16:33:42called select account. So what will
16:33:44happen? Let's say if you go to any
16:33:45website right and let's say you have
16:33:47click on this Google login page uh
16:33:49Google login button you'll see that it
16:33:50will go to the Google login page and
16:33:52there let's say you have logged in using
16:33:54two email accounts so what will happen
16:33:56right you'll be able to see that okay
16:33:57whatever email accounts that are
16:33:59available for you that is going to show
16:34:01you in this particular login page
16:34:03correct and then let's say I wanted to
16:34:04click on the first login uh first email
16:34:07so once you click on this first email
16:34:09what will happen right so it is going to
16:34:11do some kind of authentication right and
16:34:13then what will happen right? So you are
16:34:15going to have some kind of a call back
16:34:17URL. Now you might be thinking okay what
16:34:18actually this call back URL or why
16:34:20actually you need this call back URL.
16:34:22Now to explain this one in very simpler
16:34:23way you consider that actually you are
16:34:26doing the work in your application but
16:34:28when you're clicking on this Google
16:34:30button you are actually moving away from
16:34:32your application means you are not there
16:34:33in this application. So what will happen
16:34:35once the Google login is successful or
16:34:37let's say it is failed. So this Google
16:34:39login right or Google cloud console is
16:34:42going to give you a call back URL and
16:34:43that call back URL is going to come back
16:34:45to your application and this call back
16:34:47URL is going to hold some information.
16:34:49So what information is going to hold?
16:34:51It's actually going to actually verify
16:34:52that whether this login is successful or
16:34:55not. Okay, if the login is successful,
16:34:57so what you're going to do, you will
16:34:58then redirect the user back to your
16:35:00application and let's redirect the user
16:35:02to the success page. If this login is
16:35:05failed, so in that case what you're
16:35:06going to do, it will come back to your
16:35:07application and then you're going to
16:35:09redirect the user to the failure page.
16:35:11So that means logically you need three
16:35:13things. You need a client ID, you need a
16:35:14client secret and then you need a
16:35:16redirect URL. And that redirect URL we
16:35:19are going to configure in our cloud
16:35:20console. So to sum up in a simpler way,
16:35:23we are going to have a Google login
16:35:24button. We click on this Google login
16:35:26button. We are going to configure this
16:35:28one using Google client ID and client
16:35:30secret. it will go to the Google uh
16:35:32login page. There you'll be able to see
16:35:34all the emails that is available for
16:35:36you. Let's say you have three emails
16:35:37that's possible and you want to register
16:35:39using the first email or second email.
16:35:41So you click on the first email. Then
16:35:42what is going to do? It's going to do
16:35:44your authentication process and then it
16:35:46is going to go to your callback URL.
16:35:48Your call back URL is going to actually
16:35:50verify that authentication if that is
16:35:51successful or not. And based on that you
16:35:53will be back to your application again.
16:35:55And then whatever the result if it is
16:35:57success you are going to redirect the
16:35:59user to the success page. If it is
16:36:01failed you redirect the user to the
16:36:03failed page. So this is what you're
16:36:05going to do. So first of all what we
16:36:06have to do right we have to search
16:36:08something like Google cloud console.
16:36:09Okay. So this is what you have to search
16:36:11Google on Google and then you click on
16:36:13this Google cloud console and first of
16:36:16all what you have to do right you have
16:36:17to create a new project here. Now I
16:36:19already have so many projects. I'm going
16:36:20to use this for NodeJS. This is I
16:36:23usually use for my YouTube demos. So
16:36:25what you're going to do right once you
16:36:27create a simple project and then you're
16:36:28going to go to this API services and
16:36:31here what you have to do right. So first
16:36:32of all you'll see that you're going to
16:36:34get this credentials and in this uh
16:36:37credentials what you have to do you have
16:36:39to create a you see that you have to
16:36:40create credentials and you have to
16:36:42create a O client ID this client ID you
16:36:44have to do. Okay. So now I already have
16:36:46this one. So once you click on this O
16:36:49client ID right? So you have to click on
16:36:51this web client and here you can see
16:36:54that you're going to have your client ID
16:36:56and this will be your client secret and
16:36:58you'll see that you have your origin. So
16:36:59for now because we are actually so you
16:37:01see that this is for use with request
16:37:03from our browser mean when we're going
16:37:05to have our UI and whatever UI you are
16:37:07running let's say whatever port and you
16:37:09are going to use that but in our case
16:37:10because we are creating only back end
16:37:12only projects what you can do right you
16:37:14can change this one to local host 4,000
16:37:16because we are running this one on 4,000
16:37:18right so you see that we are running on
16:37:204,000 the same we have to change this
16:37:22one to 4,000 and this will be our
16:37:25callback keyword. So in our callback U
16:37:27model when you're going to configure we
16:37:28are going to do this one as local host
16:37:294,000 let's say if you're running this
16:37:32on local host 5,000 so you have to just
16:37:34configure based on that. So it will be
16:37:36SL API/ Google/ callback. Okay so now
16:37:40this will be a redirect URLs. Okay user
16:37:42will be redirect to this path after they
16:37:44have authenticated with Google and the
16:37:45same thing I've already explained.
16:37:47Correct. Now let's [snorts] save this.
16:37:49So this is the first thing we are going
16:37:50to do. So now we'll go here once again
16:37:53and then we'll go to our URL sorry env.
16:37:56Let's add our Google
16:37:59client ID Google
16:38:03client
16:38:05secret and Google
16:38:08call back
16:38:10URL. Okay. So now first of all let's
16:38:14copy this
16:38:16paste it here. Then I'm just going to uh
16:38:19disable this
16:38:21and this en sorry I have to disable this
16:38:24one and I'll delete this one.
16:38:28And then let's add one more. And then
16:38:30I'm just going to copy this. Okay. And
16:38:34then I'll paste it here. And then here
16:38:36I'm just going to use this one. So this
16:38:39will be my uh redirect UR. So these
16:38:42three things we need client ID, client
16:38:43secret and callback URL. This I'm going
16:38:45to delete later. uh so that you guys
16:38:47can't use it but just create once uh
16:38:50okay it's not that much difficult
16:38:52because once you create it will be
16:38:53easier for you to also test right so we
16:38:56need client ID client secret and call by
16:38:57keyword so now we'll go to our config uh
16:39:01let's add all of this right so we'll do
16:39:03Google client ID so I'll do check
16:39:06require env
16:39:09client secret so this this will be this
16:39:14and then what we have we have Google
16:39:16redirect
16:39:18redirect URL.
16:39:21So now let's go here and copy this
16:39:26uh copy client ID
16:39:30and we have copy client secret.
16:39:34So save this. So this is the first step.
16:39:37So now what I going to do right? So we
16:39:39are going to use a package called Google
16:39:41O library. So I'm just going to do
16:39:43Google O library and let's see.
16:39:48Now this is much more easier. Okay. And
16:39:50that is the reason and see that it's
16:39:51actually official supported official sub
16:39:53authentication client library for
16:39:55NodeJS. And this is the reason we are
16:39:57going to use this and you'll see that
16:39:58it's much more easier to use. So I'm
16:40:00just going to copy this. Let's go here.
16:40:03Right. So do npm
16:40:08and this is official. Right. Okay. So,
16:40:11we'll copy this and then we'll go and
16:40:14let's install this one.
16:40:21That's it. So, this is done. So, now
16:40:23what are we going to do? So, first we're
16:40:25going to create our Google helpers. So,
16:40:28do Google dot ds. So first let's close
16:40:31everything else and I'm going to import
16:40:35something from so Google o library and
16:40:39this will be my o to client. So first of
16:40:42all what will be our Google user profile
16:40:45means what all info we need. So first we
16:40:47need a Google ID because see remember
16:40:48when you're going to do a login
16:40:50definitely Google is going to give you a
16:40:51Google ID. Second we need a Google
16:40:53email. Google email means the actual
16:40:55email that the user is going to
16:40:56register. Okay. So that means I'm just
16:40:59going to create a type and you'll see
16:41:00that this is actually not that much is
16:41:03uh difficult to understand. So I'll do
16:41:04Google user profile and I'm simply going
16:41:07to do here Google ID
16:41:11and this will be string and we are also
16:41:14going to have a email and this will be
16:41:15string. Okay. So next what will be the
16:41:19uh step? So next we're going to create a
16:41:20Google o client. So do Google o
16:41:24client. So this will be new o client and
16:41:28you need your uh here you're going to
16:41:30pass sorry
16:41:32you're simply going to pass directly. So
16:41:34here you're going to do env that we have
16:41:37dot google client id. So env dot google
16:41:42client secret and your env dot google
16:41:45client
16:41:47google redirect.
16:41:49Okay. So now let's save this. So first
16:41:53of all what you have to do? So first uh
16:41:55let's go to routes. Okay. So we are
16:41:57going to come from routes because it
16:41:59will be easier. So I'll go to O routes
16:42:01because we are using O only here. So
16:42:04first what I have to do right? So when
16:42:06I'm going to go to this URL. So let's
16:42:08I'll do / API/
16:42:11Google. Now what will happen? See first
16:42:14of all we don't have any UI correct but
16:42:16in UI you are going to click on a button
16:42:18or you're going to click on a link or
16:42:19whatever you're going to do. Okay, let's
16:42:21say clicking on any text whatever
16:42:22continue with Google. So it will go to
16:42:25the Google login page. See in our case
16:42:26whenever we'll go to this particular or
16:42:28we are going to hit this particular in
16:42:30our browser localhost 4000/ API/op/
16:42:33Google it should go to your Google login
16:42:36page. So that means we are going to
16:42:38redirect that particular uh page to the
16:42:41Google login page. Correct? So now what
16:42:43basically this we call as Google consent
16:42:46screen. Right? So this is where you're
16:42:48going to see your Google login page. But
16:42:49how we are going to do this? So first
16:42:51I'm just going to do a router dot get
16:42:54and this will be / google and then I'm
16:42:57just going to take so do request
16:42:59response
16:43:01and here we going to do con and I have
16:43:03to create my Google or URL. Okay. So
16:43:07here I'm just going to do start Google
16:43:10login
16:43:12and now what I have to do right this is
16:43:14important. So we're going to do race and
16:43:16it's going to give you this redirect. So
16:43:17that means I'm actually redirecting from
16:43:19my application to the Google login page
16:43:22and this is what we're going to create.
16:43:23So first we will copy this. We'll go
16:43:25here and let's create this. So we'll do
16:43:27export function
16:43:29Google
16:43:31what I'm doing man. So first we are
16:43:34going to create start login. Right? So
16:43:35in this one maybe let's do one thing. Uh
16:43:38okay let's okay let's keep it here only.
16:43:41Maybe I think this only makes sense. So
16:43:43here I'm just going to do a string and
16:43:45here I'm simply going to do return and
16:43:48let's do get Google
16:43:50O URL. So I'm going to create this. So
16:43:54this is going to return a string and
16:43:55here I'm simply going to create this
16:43:57now. So what we going to do right? So
16:43:59first maybe I'm doing wrong man. No no I
16:44:02think this is not correct. Why? We
16:44:04should not keep this one in this Google
16:44:06page. So let's do one thing. This one I
16:44:08think let's keep in the service file.
16:44:10Okay. I'll tell you why. because this is
16:44:12where you're calling the service right
16:44:14so go to service go to all service sorry
16:44:16my bad here we are going to do this so
16:44:18we are going to keep this one here okay
16:44:20so this is my service and now this one
16:44:22we going to create in our helper so I'm
16:44:25just going to do here export function
16:44:28get google o url so here we'll take this
16:44:31one as string and now what actually this
16:44:33is going to return right so we are going
16:44:35to take our Google o client and then
16:44:37we're going to use the generate o url
16:44:39okay now couple of things we need to uh
16:44:42set here. So first we have to set
16:44:43something called scope. So what we going
16:44:45to set right? So here we are going to
16:44:47basically tell that we need email plus
16:44:50the profile information to identify the
16:44:52user. Okay. And that user we are going
16:44:54to store in our DB. Right? So that means
16:44:56we are going to simply tell okay this
16:44:58will be open ID. We also need email and
16:45:00this will be profile.
16:45:02Then we also need something called
16:45:04access type. In this access type will be
16:45:06online.
16:45:08And then okay this is also optional.
16:45:10Okay. So and this is optional actually
16:45:12needed for this sorry this is optional
16:45:14for refresh token. Okay now you actually
16:45:16don't need in this particular one but
16:45:18still you can keep it then we have
16:45:19something called prompt. Now this is
16:45:21important in this prompt means simply
16:45:22you are going to tell this will be
16:45:23select account. What this is going to do
16:45:25right this is going to enforce the user
16:45:27to select your email account. I already
16:45:29mentioned it. Let's say you have
16:45:30multiple email accounts. So it's going
16:45:31to give you that which one you want to
16:45:33select. So this is going to generate our
16:45:35o URL. So this is the first thing we
16:45:37have to do. So now we'll go to our o
16:45:39routes right. So we have this start
16:45:41google login that we are going to import
16:45:42from our service. So from this
16:45:44particular file and then in this service
16:45:46we're going to get our o URL. So that
16:45:49means this particular one we are going
16:45:51to do. So this is the first thing we
16:45:52have to do here. Now what will be the
16:45:54next step? Next step will be we need to
16:45:56handle our call back because I already
16:45:58mentioned once we're going to click on
16:45:59this account it's going to come back to
16:46:01your call back URL and it's going to do
16:46:03the authentication. Right? But before
16:46:04this let's do one thing. Let's go here.
16:46:06Right. I think it's already running. So
16:46:08I'm just going to close and rerun rerun
16:46:10once again. And then I'm going to copy
16:46:12this and let's go here and then do this
16:46:16slash. So you have API/
16:46:20Google.
16:46:21That's it. So this is where you're going
16:46:23to see your selector means which account
16:46:26sorry which account you are going to
16:46:27select you're getting. So that means
16:46:29this is now redirecting to your Google
16:46:32login page. Okay. So now what will be
16:46:35the next step? Next step will be we're
16:46:36going to create our second route which
16:46:39will be to handle our call back and this
16:46:40is where actual work we are going to do
16:46:42and this is where we are actually going
16:46:44to get our access token and based on
16:46:46this access token we are going to
16:46:47authenticate the user. So now next will
16:46:50be so I'm just going to do a router get
16:46:53so this will be / google/allback
16:46:57right we are using callback and then
16:46:59we're going to do async. So this will be
16:47:01request response
16:47:04next
16:47:06and first what we're going to do right
16:47:08we're going to do try catch
16:47:11so let's take error let's take like this
16:47:16and here we're going to do next we're
16:47:18going to pass error and now what we'll
16:47:20do right so first I'm just going to do
16:47:22code and this one you're going to get
16:47:24from your query so I'll do request
16:47:25doquery doc code so this is going to
16:47:27give you a code as string or this will
16:47:30be undefined. Okay. So now what we're
16:47:33going to do, right? We are going to
16:47:35create our another helper function where
16:47:38we are actually going to do what? So we
16:47:40are going to so this callback URL
16:47:42whatever we are implementing this is
16:47:45going to use that code that whatever we
16:47:47are going to receive right and it's
16:47:49going to return your profile data or
16:47:50profile information.
16:47:52So now let's do this one like this. So
16:47:54I'm just going to do export sync
16:47:56function and I'll do this one as uh what
16:47:59are we going to do? So first of all
16:48:01let's do one thing I think again I'm
16:48:02doing wrong maybe let's uh first create
16:48:05one more service because if first I'll
16:48:07create the service and then we'll create
16:48:09the helper. So first I'll do export as
16:48:12sync
16:48:13function and let's do login with Google.
16:48:17Okay, login with Google and this is
16:48:20going to receive the code which will be
16:48:22string and here the return type will be
16:48:24this will be promise of so we're going
16:48:26to receive access token the actual
16:48:28access token we're going to receive. So
16:48:29access token and this will be string. So
16:48:33now what are we going to do right? So
16:48:35first let's do con Google profile and
16:48:38this will be so first what are we going
16:48:40to do right so first we need to verify
16:48:42Google code and we need to get our
16:48:44Google profile back right so we need to
16:48:46extract the Google profile from our code
16:48:48so here I'm just going to do a and let's
16:48:51do get Google user
16:48:55from o code okay so this will be our
16:48:58method where we're going to pass this
16:48:59code here now this one we're going to
16:49:01create here okay so I was doing wrong
16:49:03because first we should create the
16:49:04service and then we will create here. So
16:49:06this is going to receive the code and
16:49:08this will be string and what this is
16:49:10going to return now this is going to
16:49:12return a promise and here we are going
16:49:13to use this Google user profile because
16:49:15we need the Google ID and the email.
16:49:17Okay. So here we're going to use this
16:49:19Google user profile type. So how we are
16:49:21going to get this? So first you have to
16:49:23give a check that if this code is not
16:49:24present. So I'm just going to throw new
16:49:27error
16:49:29not new error what I'm doing app error.
16:49:31So we're going to do an app error and
16:49:32here we're going to do 400 and let's do
16:49:35Google O code is required. So this will
16:49:40be the first step. Okay. So now next
16:49:42step will be first we're going to get
16:49:44our something from this method. So I'm
16:49:46just going to have it. So Google client
16:49:49and this is going to give you this get
16:49:50token. So you so what will happen right?
16:49:52So that is the advantage of using that
16:49:54package. So directly use this get token
16:49:56method and you just have to pass the
16:49:58code right. So here you have to get the
16:50:00code right. This is going to get the
16:50:01access token for the given code and this
16:50:03code is nothing but the authorization
16:50:05code. Okay. So here you're going to pass
16:50:06this code and this is going to give you
16:50:08the access token. So that means here
16:50:10you're going to get the tokens. Okay. So
16:50:12now what you'll do right this is
16:50:13actually very important. This first of
16:50:15all you have to check that in this token
16:50:18if the [snorts] ID token is sorry if the
16:50:19ID token is present or not. If this is
16:50:22not present so that that means that
16:50:24Google login failed. So we are going to
16:50:26do app error.
16:50:29So what will be the error code? So this
16:50:30will be 401 not because I I thought it
16:50:33will be 400. No, it will be 401. And
16:50:36here we're going to do Google login
16:50:37failed.
16:50:39Uh what I can do ID token missing
16:50:41something like this.
16:50:43So this is the first thing and then
16:50:45we're going to do what? So we're going
16:50:46to verify the token and we're going to
16:50:48read the user information from Google.
16:50:50But how we are going to do this? So I'm
16:50:52just going to do something like ticket
16:50:54info. Okay. So here we'll do a Google O
16:50:58client and then we'll do verify ID
16:51:00token. Okay. And this is where you're
16:51:02going to pass two things. So first will
16:51:03be ID token which will be what tokens do
16:51:05ID token and you're going to pass
16:51:07audience. What will be your audience? So
16:51:09audience you're going to verify from
16:51:11your env. So in your env you have this
16:51:13Google client ID. So from this client
16:51:15ID, this will be your actual unique
16:51:17client ID from where you're going to
16:51:19verify this. So this will be your Google
16:51:21client ID. Okay. So this is going to
16:51:24give you the ticket information and then
16:51:25what you're going to do right you're
16:51:26going to do con payload and this will be
16:51:30ticket info dot get payload and this is
16:51:33is going to give you the information.
16:51:35Okay now what we're going to do right
16:51:37simply I'm simply going to check if this
16:51:39payload dot sub or if this payload do
16:51:44both are not present. So I'm simply
16:51:46going to do again throw new app error
16:51:50401
16:51:51and let's do Google login field
16:51:56Google login field and this will be
16:51:58invalid user profile
16:52:02and we're going to return Google ID
16:52:05which will be your payload dot sub and
16:52:08you're going to pass the email and this
16:52:10will be your payload email but what you
16:52:12should do right you should do it too
16:52:14lower case I usually to do all this and
16:52:16then also you're going to pass a claim
16:52:18here. So now what will happen right? So
16:52:20first of all let's go through. So first
16:52:22is checking the code then it's getting
16:52:24the token using this particular method.
16:52:25It will easily give you the token. We
16:52:27are simply checking the ID token present
16:52:29or not. If it is present we are
16:52:30verifying the token. We getting the
16:52:32ticket info the user info. This is
16:52:34nothing but your user info. Okay. So
16:52:36this will be your user info
16:52:39received from Google. And then we're
16:52:42going to get our payload. If this
16:52:45payload sub and email is not present. So
16:52:47we're going to return this or else. So
16:52:49here what we so you're going to return
16:52:51the Google ID and the email. So save
16:52:53this. So now we'll go to our o routes.
16:52:56So first of all what we doing right? So
16:52:58first so in this callback we're getting
16:53:00the code and then what I'll do right. So
16:53:02first I'll do con
16:53:04something and we're going to call this
16:53:06service right. So this login with
16:53:08Google. So do a so login with Google and
16:53:12here we're going to pass the code or
16:53:14else this will be empty and what you're
16:53:16going to receive you're going to receive
16:53:17the access token right and this access
16:53:19token you're going to return at the end
16:53:21so do raise dot status so this will be
16:53:24200 dot JSON and here we're going to do
16:53:28success will be true and data will be
16:53:32this access token so this is done but
16:53:35not yet done because first of all we
16:53:36have to create our service right So
16:53:38first we're going to get our Google
16:53:40information from this method that we
16:53:42created. So to get use Google user from
16:53:44O code. So just import this.
16:53:48And now first of all let's do one thing.
16:53:49So a couple of things you have to do. So
16:53:51first see this is where you have to
16:53:55understand some of the things. So first
16:53:56we have to what we have to do right. So
16:53:58first you have to find this particular
16:54:00user from uh find this particular user
16:54:03by Google ID first. And what I mean by
16:54:05this and this particular method we are
16:54:07going to write in our repository. So
16:54:08first we have to see if that particular
16:54:10thing so not particular thing if that
16:54:12particular user is already present or
16:54:14not. Okay. So first what I'll do right
16:54:16simply so let's do one thing. So I'll do
16:54:19let user and I'm going to have it I'll
16:54:23do find user by Google ID. So the first
16:54:28thing and here what I'll do I'll do
16:54:30Google profile and see this is going to
16:54:32give you the Google ID right. So now
16:54:35what I can do right I can copy this and
16:54:37let's go to the repository
16:54:42and this is where we are going to
16:54:44implement this one right so first let's
16:54:46start with the so this will be export as
16:54:49sync function this will be find user by
16:54:53Google ID and you're going to receive
16:54:54the Google ID
16:54:57this will be string and this is going to
16:54:59return promise so either it's going to
16:55:01return your user information or else
16:55:03it's going to return null. So first I'm
16:55:05just going to do con result. So this
16:55:07will be a pull dot query.
16:55:11So this will be my user row. No, I think
16:55:14we have DB user row. Correct? We have DB
16:55:16user row. And here we are going to use.
16:55:22So we'll do select id email ro
16:55:28and let's do created at all these from
16:55:32users and now what we'll do where so
16:55:35let's go here and let's go to user and
16:55:38see that we have this Google ID see
16:55:39everything is linked so now I can simply
16:55:41check if this Google ID is equal to this
16:55:45right and then we going to pass this
16:55:47Google ID here so this is going to give
16:55:48me the information if that is present or
16:55:50not
16:55:52So I'm going to return result dot rows
16:55:54of zero
16:55:56or else null.
16:55:59So save this. Now I'll go to our
16:56:01service. So this will be first we are
16:56:03finding the user right. If this user is
16:56:06not present. So what are we going to do?
16:56:08So first first let's see if this is not
16:56:11present. So in that case what we're
16:56:13going to do right. So we are actually
16:56:14going to check if this particular email
16:56:17is already exist or not. So that means
16:56:20what I mean by [snorts] this now this is
16:56:21actually very important what I'm trying
16:56:23to say. So let's say that is one
16:56:25particular user right and if this
16:56:28particular user already logged in with a
16:56:31certain email and the same user try to
16:56:34log in another time using Google login.
16:56:37So that means what I'm trying to say. So
16:56:39let's say if I go here I'm not sure if
16:56:41you're getting so let's say same user a
16:56:44user already registered with one
16:56:46particular email. Okay. So it's like
16:56:49email ABC.com
16:56:50whatever it is and the same user is try
16:56:54to use or try to use the Google login
16:56:57and try to login with the same email. So
16:56:59that should not happen. So in that case
16:57:01what I'm going to do right. So first
16:57:02let's import this. So here I'm just
16:57:04going to do user and this will be a and
16:57:07I'm just going to do find user by email
16:57:10now. So this is the first thing and here
16:57:12I'm just going to do Google profile do
16:57:14email and this will be another method we
16:57:16are going to create where we are going
16:57:18to create in our find user by email
16:57:20right I think find user by email we
16:57:22already have
16:57:24find user by email okay this one we can
16:57:26use so this is what we going to use here
16:57:28so I'm simply going to do user will be
16:57:30find user by email and now what I'm
16:57:33going to do I'm simply going to check if
16:57:34this user is present so in this case
16:57:38there are two option so first one will
16:57:40be we need to link this Google account
16:57:42to the existing user or second if this
16:57:46is a first time login so in that case we
16:57:48need to create the user in the DB I know
16:57:50this is little complicated so what I
16:57:51mean by this if this user you are
16:57:53already getting so you need to link this
16:57:56user because this user is again try to
16:57:58login using Google so you need to link
16:58:00this user or link this Google account
16:58:04to the existing
16:58:07email user Okay. And the second scenario
16:58:11will be if this is not the case. So in
16:58:13that case if it is a first time Google
16:58:15login
16:58:16so we need to create the user
16:58:22in postgress. So that means it's the
16:58:24first time login and it say u new email.
16:58:28So in that case we have to create this
16:58:29user. So that means the first one will
16:58:31be user will be equal to a and I'll do
16:58:34link Google
16:58:36ID to user. And here we're going to pass
16:58:40this user do ID and I'm going to pass
16:58:42the Google profile dot Google ID both.
16:58:46Okay. So this is if the user is pres
16:58:48already present. If this is not present
16:58:50so else case. So we're going to create a
16:58:52new user. So here I'm just going to do
16:58:54user will be have it create Google
16:58:59user. So here I need the Google profile
16:59:02email and Google profile. Google ID.
16:59:06Okay. So this is what we going to do. So
16:59:08now what you can do right you can create
16:59:10both. So I'll do link Google to user.
16:59:15So we'll do export as sync function. So
16:59:18I'll do link
16:59:20uh Google to user. So for this one what
16:59:23we going to do right? We're going to
16:59:24what we're sending here user ID and
16:59:27Google ID. So do user ID. This will be
16:59:30string and this will be Google ID. This
16:59:33will be also string. And here we're
16:59:35going to return promise and this will be
16:59:38user.
16:59:40So I'll do con this will be result and
16:59:43here we're going to do a pool dot query.
16:59:47So this will be DB user
16:59:51no pool dotquery DV user row and here
16:59:55we're going to now do what we going to
16:59:57link this user. How we going to link?
16:59:59We're going to update. So we're going to
17:00:00update the user and then I'm just going
17:00:03to do set. So I'll do set Google ID
17:00:08equal to this and also I'm just going to
17:00:12do updated at. So I'll do updated at
17:00:15equal to now
17:00:18where we need to check right. So where
17:00:20what where the user ID is this. So that
17:00:22means where your ID is equal to this. So
17:00:25this ID is nothing but your user ID this
17:00:28one. Okay. So this is what and then at
17:00:31the end I'm just going to do return in
17:00:33ID email
17:00:36role and here I'm just going to do
17:00:38created add
17:00:40and now I can simply pass this. So first
17:00:42one will be my Google ID and second one
17:00:45will be my user ID
17:00:47and then we're going to return result
17:00:49dot rows of zero. So save this. So now
17:00:53this is going to link your existing user
17:00:56sorry link this Google account to the
17:00:58existing email user. if this user is
17:01:00already present. Okay, so this is what
17:01:02we're going to import. If this user is
17:01:03not present, if this is a first time
17:01:05login, we're going to create the Google
17:01:06user. Okay, so here this will be. So
17:01:09let's go here. So I'm just going to do
17:01:11export as sync function. So do create
17:01:16Google user. So what are the things we
17:01:19are sending? We sending email and Google
17:01:22ID. So do email string
17:01:26Google id string. What this is going to
17:01:30return again it's going to return
17:01:32promise user.
17:01:34So now so this will be con result.
17:01:38So this will be a pull dot query
17:01:44and here we are going to simply do.
17:01:47So this will be add right. So we are
17:01:49going to insert. So insert into users
17:01:54uh no sorry insert into users. So you
17:01:56need to mention what you want to insert.
17:01:58So you need to insert email and the
17:02:01Google ID. Right? So you have to do
17:02:02Google ID. I'm not sure what is that
17:02:05Google ID.
17:02:08Okay. And then we're going to pass the
17:02:10values. So values will be your 1 comma
17:02:122. And then you're going to do
17:02:14returning. So we're going to do id email
17:02:17role
17:02:20and we're going to do created add.
17:02:24So I think that's it. And then we're
17:02:26going to pass the email
17:02:28and the Google ID
17:02:31and again the same thing. So do result
17:02:34dot rows of zero. So save this. So now
17:02:39what we're going to do right we're going
17:02:40to simply import this one here. So if
17:02:43you can understand all of this right. So
17:02:45I think you'll see that it's not that
17:02:47much difficult. Okay, what we getting?
17:02:48We have to return the token that is
17:02:50fine. So that means first we're checking
17:02:51if this uh so here first we are finding
17:02:54this user right and here if this is this
17:02:57not equal to true then we have try to
17:02:59find the user from email. So first we
17:03:01try to find the user using Google ID. If
17:03:04this is not the case so in that case
17:03:06we'll try to find the user using email.
17:03:08If this user is already present we're
17:03:10going to link that user. If that not
17:03:12present first time login we're going to
17:03:13create the user. Okay. So now what I can
17:03:16do right where is that this one. So
17:03:18after this I'm just going to do con. So
17:03:21do access token and this will be
17:03:25so create access token. I think we don't
17:03:27have created this one. Right? So we're
17:03:29going to create this one. So let's do
17:03:31one thing. I'm simply going to do
17:03:33function. Let's do create access token
17:03:38for user. And here I'm just going to get
17:03:41the user. And this will be my user type.
17:03:44And this is going to return a string.
17:03:46And here I'm just going to do return
17:03:49sign access token.
17:03:51Sign access token will be
17:03:54this one. Right? So here we're going to
17:03:55pass the sign access token. And we're
17:03:58going to pass your user ID which will be
17:04:00your user do ID. Email will be user do
17:04:05email and role will be user dot ro.
17:04:11Okay. So this will be what we're going
17:04:12to do. So this is going to create your
17:04:14user information, pass the user and at
17:04:17the end you're going to return the
17:04:18access token.
17:04:21And this is done. Now this is actually a
17:04:24long process but if you take some time
17:04:26and try to understand everything is
17:04:28linked. So if you go here right I try to
17:04:30understand. So let's see it will go to
17:04:32Google with login sorry Google with
17:04:34login with Google first. Try to f the
17:04:37Google profile. So here we are simply
17:04:40checking based on the authorization code
17:04:42we're going to take our tokens get the
17:04:44ticket info or the user info uh get the
17:04:47payload and return the Google ID and the
17:04:49email once it will get the Google uh
17:04:52Google ID and the email it will try to
17:04:53find the user if this user is not
17:04:56present it will try to find the user by
17:04:58the email if this user is present with
17:05:00the email it's going to link this Google
17:05:02account or else it's going to create the
17:05:04user for the first step then it will
17:05:06create the token and return the token
17:05:08And that's it. So now let's see if I try
17:05:11to go to let's say localhost 4,000
17:05:16uh 4,000/ API/
17:05:19Google and let's I try to click on this
17:05:22email.
17:05:25That's it. And you can see that you're
17:05:27getting data and this is your access
17:05:29token, right? And what you can do that
17:05:31you can verify this also if this is
17:05:33working or not. So what I'll do, right?
17:05:35So let's see if I go here. Not this.
17:05:38Let's clear this. I think I've added
17:05:40this one in some place. Let me just
17:05:42check. Okay, this one. Let's copy this
17:05:45and let's execute this here. And now I'm
17:05:48just going to do select ID, email, and
17:05:50ro from user. Okay, paste this. Enter.
17:05:54And now we'll see that you have a
17:05:56samukhargi 2022
17:05:58at thegmail.com. So that means these
17:06:01user created using Google login. These
17:06:03two user created using normal login and
17:06:05this is manual admin. So that means with
17:06:07this you can understand every possible
17:06:10way that how you can create user. Okay.
17:06:13So with this now Google login is
17:06:15completed and with this we have finally
17:06:18completed this particular video. I think
17:06:20we don't have that much to cover as I
17:06:22already mentioned that we I'm going to
17:06:24cover uh so many other things also in
17:06:27the part three but see that is not going
17:06:28to come anytime soon but that will come
17:06:31in the part three. uh I'm going to cover
17:06:33very advanced concept like worker
17:06:35threads and all these child processes.
17:06:37Uh there will be some more advanced
17:06:39topic like cookies and everything
17:06:40deployment and everything. But for now I
17:06:43already have multiple deployment videos.
17:06:44You can watch those videos. But with
17:06:47this that's all for this particular
17:06:49video. I will see you in my next video.
17:06:50Till then good luck and peace.

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