The document discusses Express.js, a web framework for Node.js. It provides an overview of Express.js and how it can be used to start an application server listening on a port, handle HTTP requests asynchronously with methods like GET and POST. It also includes code samples of setting up a basic Express server with a "Hello World" route, installing Express, and using routes to define how the app responds to different URIs and HTTP methods.

1. Workshop
@
Ramnshee Infotech
By Jainul Musani
1
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Express JS

2. ExpressJs
 Express.js is a web framework that could be used
with Node.js.
 Express.js can start an application server
listening on a port in your machine.
 Express.js starts the application in a single
thread and handles HTTP methods like GET, POST,
DELETE, etc., asynchronously.
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Express JS

3. ExpressJs – Sample Server
 app.js
var express = require('express')
var app = express()
app.get('/', function (req, res) {
res.send(‘Started Server with ExpressJs FrameWork')
res.end()
})
app.listen(8000)
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Express JS

4. Install Express.js
 Assuming you’ve already installed Node.js,
 create a directory to hold your application, and make
that your working directory.
C:nodejs> mkdir myapp
C:nodejs> cd myapp
 Use the npm init command to create a package.json file
for your application.
C:nodejs> npm init –y
 Now install Express in the myapp directory and save it
in the dependencies list.
C:nodejs> npm install express –save
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5. Hello world example - Express.Js
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 at
http://localhost:${port}`)
})
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6. Run “Hello World”
 Run the app with the following command:
C:nodejs> node app.js
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7. Express.js Routes
 An Express.js Route defines how our Express application
can respond to a client request to with a specific URI (or
path) and a specific HTTP request method (GET, POST,
etc.).
 A basic Express application as shown below.
app.js
var express = require('express')
var app = express()
// start the server
var server = app.listen(8000, function(){
console.log('Listening on port 8000...')
})
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8. Express.js Routes
 Here Express.js Routes come into picture.
app.get('/', function (req, res) {
res.send('This is a basic Example for Express.js')
})
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Training Batch - Winter

9. Express.js Routes app.js
var express = require('express')
var app = express()
app.get('/', function (req, res) {
res.send('Home.')
})
app.get('/hello/', function (req, res) {
res.send('Hello page.')
})
app.get('/bye/', function (req, res) {
res.send('Bye page.')
})
var server = app.listen(8000, function(){
console.log('Listening on port 8000...‘) // start the server
})
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Express JS