Requesting in http vs Requesting in Express.js

09 Feb, 2021
Node.js: Node.js is an open-source and cross-platform runtime environment for executing JavaScript code outside a browser. You need to remember that Node.js is not a framework and it’s not a programming language. Most of the people are confused and understand it’s a framework or a programming language. We often use Node.js for building back-end services like APIs like Web App or Mobile App.
http Module
Import http module: Import http module and store returned HTTP instance into a variable.
Syntax:
var http = require("http");
Creating and Binding Server: Create a server instance using createServer() method and bind it to some port using listen() method.
Syntax:
const server = http.createServer().listen(port)
Parameter: This method (listen()) accepts a single parameter as mentioned above and described below:
port <Number>: Ports are in the range 1024 to 65535 containing both registered and Dynamic ports.
The below example illustrate the use of http module in Node.js.
Example 1: Filename: index.js
javascript
// Node.js program to create http server // using require to access http module  const http = require("http"); // Port numberconst PORT = process.env.PORT || 2020; // Creating serverconst server = http.createServer(   // Server listening on port 2020  function (req, res) {     res.write('Hello geeksforgeeks!');      // Write a response to the client     res.end();   }).listen(PORT, error => {   // Prints in console   console.log(`Server listening on port ${PORT}`)});
Run index.js file using the following command:
node index.js
Output:
Server listening on port 2020
Express Module
In order to use the express module, we need to install the NPM (Node Package Manager) and the following modules (on cmd).
// Creates package.json file
>> npm init 

// Installs express module
>> npm install express --save // OR
>> npm i express -s 
Import express module: Import express module and store returned instance into a variable.
Syntax:
var express = require("express");
Creating Server: The above syntax calls the “express()” function and creates a new express application which gets stored inside the app variable.
Syntax:
const app = express(); // OR 
var express = require("express")(); 
Sending and listening to the response: It communicates the request and response with the client and the server. It requires PORT <number> and IP <number> to communicate.  
app.listen(PORT, IP, Callback);
Parameter: This method accepts three parameters as mentioned above and described below:
PORT <Number>: Ports are the endpoints of communication which helps to communicate with the client and the server.
IP <Number>: IPs represent IPv4 or IPv6 address of a host or a device.
Callback <Function>: It accepts a function.
The below example illustrates the Express.js module in Node.js.
Example 2: Filename: index.js
javascript
// Node.js program to create server // with help of Express.js module // Importing express const express = require('express'); // Creating new express app const app = express(); // PORT configurationconst PORT = process.env.PORT || 2020; // IP configurationconst IP = process.env.IP || 2021; // Create a route for the appapp.get('/', (req, res) => { res.send('Hello Vikas_g from geeksforgeeks!');}); // Create a route for the appapp.get('*', (req, res) => { res.send('OOPS!! The link is broken...');}); // Server listening to requestsapp.listen(PORT, IP, () => { console.log(`The Server is running at: http://localhost:${PORT}/`);});
Run index.js file using the following command:
node index.js
Output:
The Server is running at: http://localhost:2020
Now type http://127.0.0.1:2020/ OR http://localhost:2020/ in a web browser to see the output.
mridulmanochagfg
Express.js
Node.js-Misc
Node.js
Web Technologies
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