Requesting in http vs Requesting in Express.js

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 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:

const 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 illustrates 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 number
const PORT = process.env.PORT || 2020;

// Creating server
const 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}`)
});

Steps to run the application:

Run the 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 the express module and store returned instance into a variable.

Syntax:

const 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 
const 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 that help 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 configuration
const PORT = process.env.PORT || 2020;

// IP configuration
const IP = process.env.IP || 2021;

// Create a route for the app
app.get('/', (req, res) => {
 res.send('Hello Vikas_g from geeksforgeeks!');
});

// Create a route for the app
app.get('*', (req, res) => {
 res.send('OOPS!! The link is broken...');
});

// Server listening to requests
app.listen(PORT, IP, () => {
 console.log(
`The Server is running at: http://localhost:${PORT}/`);
});

Steps to run the application:

Run the 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.