Node.js: Basic Routing [Beginner Tutorial]

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This article shows how you can create a basic HTTP routing in Node.js.

In the example code, we will be using two built-in Node.js modules: http module and fs module. To create HTTP server, we need http module. And, to read/write file data, we need to use fs module.

We will create an http server and write if/else conditions to read HTML files according to routing parameter.

To read HTML files, we use fs.createReadStream() function. createReadStream reads file in chunks of specified size. It’s better than using fs.readFile() function which loads the entire file into memory before processing.

With createReadStream, we use pipe() event which helps in writing response data to browser.

Let’s first create 3 html files: index.html, about.html, contact.html

index.html


<html>
    <head>
        <title>Homepage</title>
    </head>
    <body>
        <h1>Homepage</h1>
        This is homepage.
    </body>
</html>

about.html


<html>
    <head>
        <title>About Us</title>
    </head>
    <body>
        <h1>About Us</h1>
        This is about page.
    </body>
</html>

contact.html


<html>
    <head>
        <title>Contact Us</title>
    </head>
    <body>
        <h1>Contact Us</h1>
        This is contact page.
    </body>
</html>

Now, here’s our Nodejs file that creates server and does the routing. Let’s name it main.js.

main.js


var http = require('http');
var fs = require('fs');

http.createServer(function (request, response) {
    // print the URL in terminal
    console.log('URL: ' + request.url);
    
    if (request.url == '/about') {
        response.writeHead(200, {'Content-Type': 'text/html'});
        // pipe event is used to write response data
        fs.createReadStream('about.html').pipe(response); 
    } else if (request.url == '/contact') {
        response.writeHead(200, {'Content-Type': 'text/html'});     
        fs.createReadStream('contact.html').pipe(response); 
    } else {
        response.writeHead(200, {'Content-Type': 'text/html'});     
        fs.createReadStream('index.html').pipe(response); 
    }   
}).listen(8081);

// This prints the message in terminal when you run "node server.js"
console.log('Server running at port 8081: http://127.0.0.1:8081');

Now, open terminal/command-prompt and go to the directory where your main.js file is. My main.js file is at /var/www/html/test/nodejs/main.js.

After you are in the directory where the above created main.js file is, then run the following command:

node main.js

This will print the message in your terminal/command-prompt saying “Server running at port 8081…” like below:


mukesh@chapagain:/var/www/html/test/nodejs$ node main.js
Server running at port 8081: http://127.0.0.1:8081

Now, open your browser and type the following in your browser’s address bar:

http://127.0.0.1:8081

Press Enter and you shall be able to see content of index.html file loaded on your browser.

http://127.0.0.1:8081/about will show content of about.html file.
http://127.0.0.1:8081/contact will show content of contact.html file.
Any other parameters in the URL will show content of index.html file. For example,
http://127.0.0.1:8081/xyz will show content of index.html file.

That’s it! You have successfully created a basic HTTP routing in Node.js.

Hope this helps. Thanks.

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