Node.js Web Server
Node.js is a powerful JavaScript runtime that enables developers to build scalable and efficient web servers. In this article, we’ll walk through the steps to create a simple web server using Node.js, covering the basics and providing a foundation for more advanced applications.
Node.js has a built-in module called HTTP, which allows Node.js to transfer data over the Hypertext Transfer Protocol (HTTP). The HTTP module can create an HTTP server that listens to server ports and gives a response back to the client.
Setting Up Your Project
Step 1: Create a Project Directory
Start by creating a new directory for your project and navigate into it:
mkdir node-web-server
cd node-web-server
Step 2: Initialize a Node.js Project
Initialize a new Node.js project using npm
npm init -y
This command creates a package.json file with default settings.
Building the Web Server
Step 1: Create the Server File
Create a file named server.js in your project directory. This file will contain the code for your web server.
Step 2: Import Required Modules
At the top of server.js, import the http module, which is built into Node.js.
const http = require('http');
Step 3: Create the Server
Use the http module to create a server. The createServer method takes a callback function that is executed whenever a request is received
const server = http.createServer((req, res) => {
res.statusCode = 200; // Set the status code to 200 (OK)
res.setHeader('Content-Type', 'text/plain'); // Set the content type to plain text
res.end('Hello, World!\n'); // Send a response
});
Stpe 4: Specify the Port and Start the Server
Define the port the server will listen on and start the server
const PORT = 3000;
server.listen(PORT, () => {
console.log(`Server running at http://localhost:${PORT}/`);
});
Step 5: Complete server.js
Your server.js file should now look like this
const http = require('http');
const server = http.createServer((req, res) => {
res.statusCode = 200;
res.setHeader('Content-Type', 'text/plain');
res.end('Hello, World!\n');
});
const PORT = 3000;
server.listen(PORT, () => {
console.log(`Server running at http://localhost:${PORT}/`);
});
Run the Server
In your terminal, run the server using Node.js
node server.js
Example 1: Implementation to show the web server creation in Node.js.
// Import the Node.js http module
const http = require('http');
// req is the request object which is
// coming from the client side
// res is the response object which is going
// to client as response from the server
// Create a server object
http.createServer(function (req, res) {
// 200 is the status code which means
// All OK and the second argument is
// the object of response header.
res.writeHead(200, { 'Content-Type': 'text/html' });
// Write a response to the client
res.write('Congrats you have a created a web server');
// End the response
res.end();
}).listen(8081); // Server object listens on port 8081
console.log('Node.js web server at port 8081 is running..')
Run the Server
In your terminal, run the server using Node.js:
node server.js
The http.createServer() method includes a request object that can be used to get information about the current HTTP request e.g. url, request header, and data.
Example: The following example demonstrates handling HTTP requests and responses in Node.js.
// Import Node.js core module i.e http
const http = require('http');
// Create web server
const server = http.createServer(function (req, res) {
// Check the URL of the current request
if (req.url == '/') {
// Set response header
res.writeHead(200, { 'Content-Type': 'text/html' });
// Set response content
res.write(
`<html><body style="text-align:center;">
<h1 style="color:green;">w3wiki Home Page</h1>
<p>A computer science portal</p>
</body></html>`);
res.end();//end the response
}
else if (req.url == "/webtech") {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.write(`
<html><body style="text-align:center;">
<h1 style="color:green;">Welcome to w3wiki</h1>
<a href="https://www.w3wiki.net/web-technology/">
Read Web Technology content
</a>
</body></html>`);
res.end();//end the response
}
else if (req.url == "/DS") {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.write(`<html><body style="text-align:center;">
<h1 style="color:green;">w3wiki</h1>
<a href="https://www.w3wiki.net/data-structures/">
Read Data Structures Content
</a>
</body></html>`);
res.end(); //end the response
}
else if (req.url == "/algo") {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.write(`<html><body style="text-align:center;">
<h1 style="color:green;">w3wiki</h1>
<a href="https://www.w3wiki.net/fundamentals-of-algorithms/">
Read Algorithm analysis and Design Content
</a>
</body></html>`);
res.end(); //end the response
}
else
res.end('Invalid Request!'); //end the response
// Server object listens on port 8081
}).listen(3000, () => console.log('Server running on port 3000'));
In the above example, req.url is used to check the url of the current request, and based on that it sends the response.
Command to Run code:
node index.js
URL: localhost:3000/webtech
URL: localhost:3000/DS
URL: localhost:3000/algo