Routing in NodeJS

Routing is the process of deciding how a server should respond to different requests made by users. When you visit a website or use an app, your browser sends a request to the server. Routing determines how the server handles these requests based on the URL you visit and the type of request (such as viewing a page, submitting a form, or deleting something).

There are mainly two ways to implement routing in NodeJS

1. Routing with the Native HTTP Module

In NodeJS, routing is done by directly using the built-in http module to create a server that listens for client requests. You manually handle different HTTP methods and URLs. This gives you full control over the request/response cycle, but it requires more boilerplate code and manual handling of request data.

How It Works

• You create an HTTP server with http.createServer().
• Inside the server's callback function, you inspect the incoming request (req), including its URL (req.url) and HTTP method (req.method).
• Based on these parameters, you can determine which functionality to execute (i.e., which route to trigger).

const http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, { 'Content-Type': 'text/html' });

    const url = req.url;

    if (url === '/about') {
        res.write(' Welcome to about us page');
        res.end();
    }
    else if (url === '/contact') {
        res.write(' Welcome to contact us page');
        res.end();
    }
    else {
        res.write('Hello World!');
        res.end();
    }
}).listen(3000, function () {
    console.log("server start at port 3000");
});

To start the application run the following command

node index.js

Output

Routing Using Express Framework

Express.js is a minimalist web framework for NodeJS that simplifies routing and server-side application management. With Express, routing becomes simpler and more intuitive.

You don’t need to manually check request methods and URLs; instead, Express provides dedicated methods for handling different HTTP requests, such as app.get(), app.post(), etc.

How It Works:

• Install Express using npm install express.
• Create an Express app by calling express().
• Define routes using Express methods like app.get(), app.post(), etc.
• Start the server and listen for incoming requests.

For a GET request using the app.get() method:

const express = require('express')
const app = express()

app.get('/', function(req, res) {
    res.send('Hello Geeks')
})

For POST requests use the app.post() method:

const express = require('express')
const app = express()

app.post('/', function(req, res) {
    res.send('Hello Geeks')
})

The below code example is using express framework for creating routes

const express = require('express');
const app = express();
const port = 3000;

app.get('/', (req, res) => {
    res.send('Hello World!');
});

app.get('/about', (req, res) => {
    res.send('Welcome to about us page');
});

app.get('/contact', (req, res) => {
    res.send('Welcome to contact us page');
});

app.listen(port, () => {
    console.log(`Server is running on http://localhost:${port}`);
});

Output