Backend Code in Production

✅check Requirements

Open Terminal and type

• node -v Prefered 18 or higher
• npm - v

Understanding Working

 Computer / Mobile -> request -> [Express] -> Server 

 Computer / Mobile <- [Express] <- Response Server 

• Task :-

  • Go to any url say https://www.postman.com/ ; what happens here is

  • server Listens to the request , and server decides response

  • All the listening work is done by package $Express$

  • Route terms :-

    • visiting https://www.postman.com/ means you are visting home route ; represented by /
    • visting https://identity.getpostman.com/#means you are visting /# , entering user details setup

  • Types of request:-

    • $GET$ : basic requesting ; visting any url ; to get the service from the server of that url website

Start Project

• Make a new folder say Chaideploy in VSCode and open terminal

  • Make an empty Node application . How ?
    • simply npm init in terminal
      • $💡ProTip$ :- do npm init -y only when yes to all defaults
    • observe the output
  • fill the needed ; leave the rest to default by just clicking ENTER to next
    • entry point :(index.js)
    • test command :
    • git repository:
    • keywords : node chai
    • author : YourName(anything)
    • license:(ISC)
  • You will get a summary of all filled details ;
  • Now check the automatically generated file : $package.json$

• Make a new file $index.js$

  • to test write

    console.log("Hello World")
  • run by typing node index.js in terminal

• But How to run using package.json ?

  • use $Scripts$ commands
  • go to package.json and modify the code for scripts

    "scripts" :{
       "start" : "node index.js"
    }
    • $💡ProTip$ : - common approaches are build , dev
  • But will it do ; when we run npm run start
    • actually command run will be node index.js
    • observe that terminal terminates after running the file

• Installing $Express$

  • Go to official docs of express ; search in browser
    • simply run npm install express in terminal
  • check package.json if installed
  • visit getting started , Hello world section in docs

• Code part

  To be written in index.js file

  const express = require('express')
  const app = express()
  const port = 3000 
  app.get('/' , (req , res) =>{
      res.send("Hello World")
  })
  
  app.listen(port , ()=>{
      console.log("Example app listening to port ${port}")
  })

• Code Explaination

1. const express = require('express')
   • Style of writing : common vs modulejs
   • importin package ; use as it is

2. const app = express()
   • app is a object like Math in JS ; we use Math.random()

3. const port = 3000 
   • There are about 65K + available virtual ports that are free to use
   • listening to server
   • Not fixed ; can use 2000 or 4000 too

4.  app.get('/' , (req , res) =>{
        res.send("Hello World")
    })
   • / : Denotes Home Route
   • At this home route listen to the request , we will give a callback , sending message using res.send() :- response
   • can we handle more requests like these? Yes

     • app.get('/twitter' , (req , res) =>{
       res.send("Hello World")
       })
     • '/twitter' :- it is route
     • (req , res) =>{} : - callback

5.     app.listen(port , ()=>{
       console.log("Example app listening to port ${port}")
   })

   if succesfully listening we get a this Message response in terminal

• Run The application

  • run in terminal npm run start
  • 📝: Terminal didnt terminated ; means that app is listening to the requests constantly
  • 🎉 Congrats!! You made a server
  • How to visit the url
    • go to http://localhost:3000 or 127.0.0.1:300
    • depending on the localhosting url of pc

• Make More

  • app.get('/#' , (req , res)=> {
      res.send('<h1>Please Login </h1>)
    })
  • write in index.js file
  • run at http://localhost:3000/#
  • Problem occurs ; cannot GET/# at the page ,What and how ?
  • Concept of Hot Reloading ;in react app , every change is saved and reloaded automatically But here we have to reload manually
  • Solution restart the application by :-
    • ctrl+c/break in terminal
    • npm run start again

• One More

  • app.get('/youtube' , (req , res)=> {
      res.send('<h2>Welcome to my yt channel</h2>)
    })
  • restart the app and see the output

Production Deployment

We get some special variables which need to be taken care of ; like sensetive info , Db username .Also the port assigned in our pc works fine but who knows it is free or not on client

• install dot env ; go to Docs
• npm i dotenv run in terminal
• Make a new file .env and writePORT= 3000
  • standard practice to write in capitals
• How to use ;
  • At the start of index.js add at the top
    • require('dotenv').config()
  • Also change

    • app.listen(process.env.PORT , ()=>{
      console.log("Example app listening to port ${port}")
      })
• run the application and see the changes

Deployment

Git and Github

• Go to github
  • create a new repositary say chaibackend
  • Add description
  • ✅ public and create
• if not done yet , do git ssh setup to configure your pc
• In terminal run the following commands
  • git init
  • $💡ProTip$ : Make a .gitignore file and add
    • node_modules
    • .env
  • git add .
  • $💡ProTip$ : Way to visulize , git section left sidebar
  • git commit - m "first commit"
  • git branch -M main
  • git remote add origin repo_link : add repo_link created
  • git push -u origin main

Devops

• Deployment Alternatives

  DigitalOcean , Heroker , railway , seanode , render , cyclic

• Steps to follow

  • resource :- Github

    • check repo , branch and source directory
    • Auto refresh

  • Edit Plan : Basic

  • Env Variables:

    • global and repo name both write ; both have difft scope

    • key	value
      PORT	3000

    • for system security
    • port is overwritten automatically; DB part will not

  • Check info summary

    • go to build logs to check live progress
    • check apps : - url

• Wtite to index.js

  • const githubData = 'https://api.github.com/users/{GithubName}'
  • replace your {GithubName} with your github name

• To production just push to github

  • select build in app
  • $Protip💡$ : cmd - console features; insights ; console ; activity

• Destroy app in Actions

File structure

• node_modules
• .env
• .gitignore
• index.js .package.json .package-lock.json