This article shows how Node.js creates HTTP servers. It covers requests, responses, routes, HTML, JSON, and gives examples for both intermediate and advanced use cases.
Table of Content
What is Node.js HTTP Server?
A Node.js HTTP server is a process that listens on a port and answers client requests. It allows developers to send data, serve files, or return responses to browsers.
Node.js uses the built-in http module to create servers. This module runs without extra setup and handles each request with an event-driven model.
Node.js uses the built-in http module to create servers. This module runs without extra setup and handles each request with an event-driven model.
const http = require('http');
const server = http.createServer((req, res) => {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello from Node.js HTTP server');
});
server.listen(3000, () => {
console.log('Server runs on port 3000');
});This code imports the http module, creates a server, and sets it to listen on port 3000. The server returns a plain-text message for any request.
A Node.js server reads each request and decides what response to send. It can read headers, method, and URL to send the right content.
How to Add Routes in an HTTP Server
You can check the request URL to decide what content to return. This allows you to build multiple paths inside the same server.
const http = require('http');
const server = http.createServer((req, res) => {
if (req.url === '/') {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Home Page');
} else if (req.url === '/about') {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('About Page');
} else {
res.writeHead(404, {'Content-Type': 'text/plain'});
res.end('Page Not Found');
}
});
server.listen(3000);This code checks the URL and sends a different response for each path.
Serving HTML and JSON with Node.js HTTP Server
You can serve HTML files or JSON data. HTML helps show pages in browsers, and JSON helps return data for APIs.
const http = require('http');
const server = http.createServer((req, res) => {
if (req.url === '/html') {
res.writeHead(200, {'Content-Type': 'text/html'});
res.end('<h1>Welcome to HTML page</h1>');
} else if (req.url === '/json') {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify({ message: 'Hello JSON' }));
} else {
res.writeHead(404, {'Content-Type': 'text/plain'});
res.end('Page Not Found');
}
});
server.listen(3000);This code shows how to serve HTML content and JSON data from one server.
Examples
Basic Text Response:
const http = require('http');
const server = http.createServer((req, res) => {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Basic Text Response');
});
server.listen(4000);This example creates a server on port 4000 that returns a plain-text response for all requests. It is simple and helps beginners learn the basics.
Multiple Routes with JSON Data:
const http = require('http');
const server = http.createServer((req, res) => {
if (req.url === '/users') {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify([{name: 'Ali'}, {name: 'Sara'}]));
} else if (req.url === '/status') {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify({status: 'Server OK'}));
} else {
res.writeHead(404, {'Content-Type': 'text/plain'});
res.end('Not Found');
}
});
server.listen(4001);This example shows a server with two JSON routes and a 404 fallback. It helps you handle structured data with different paths.
Serve HTML File from Disk:
const http = require('http');
const fs = require('fs');
const server = http.createServer((req, res) => {
if (req.url === '/page') {
fs.readFile('index.html', (err, data) => {
if (err) {
res.writeHead(500, {'Content-Type': 'text/plain'});
res.end('Error loading file');
} else {
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(data);
}
});
} else {
res.writeHead(404, {'Content-Type': 'text/plain'});
res.end('Page Not Found');
}
});
server.listen(4002);This example shows how to serve an HTML file from the disk. It reads the file and returns its content when the client visits /page.
Advanced Routing with Methods:
const http = require('http');
const server = http.createServer((req, res) => {
if (req.method === 'GET' && req.url === '/data') {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify({message: 'GET data'}));
} else if (req.method === 'POST' && req.url === '/data') {
let body = '';
req.on('data', chunk => body += chunk);
req.on('end', () => {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify({received: body}));
});
} else {
res.writeHead(404, {'Content-Type': 'text/plain'});
res.end('Not Found');
}
});
server.listen(4003);This example shows a server that handles GET and POST requests on the same route. It collects posted data and returns it as JSON.
Wrapping Up
You learned what a Node.js HTTP server is and how it handles requests, responses, routes, and different data types. Here is a quick recap:
- Node.js can create an HTTP server with the built-in module.
- It can handle different URLs and return text, HTML, or JSON.
- It can read data from files and send it to clients.
- It can handle GET and POST methods for advanced cases.
FAQs
How do I create a simple Node.js HTTP server?
const http = require("http");
const server = http.createServer((req, res) => {
res.writeHead(200, { "Content-Type": "text/plain" });
res.end("Hello, World!");
});
server.listen(3000, () => {
console.log("Server running at http://localhost:3000/");
});
http.createServer to create a server and listen to start it on a port.
How to handle different routes in Node.js HTTP server?
const http = require("http");
const server = http.createServer((req, res) => {
if (req.url === "/") {
res.writeHead(200, { "Content-Type": "text/html" });
res.end("<h1>Home Page</h1>");
} else if (req.url === "/about") {
res.writeHead(200, { "Content-Type": "text/html" });
res.end("<h1>About Page</h1>");
} else {
res.writeHead(404, { "Content-Type": "text/plain" });
res.end("404 Not Found");
}
});
server.listen(3000);
req.url to check the path and serve different responses.How can I send JSON response with Node.js HTTP server?
const http = require("http");
const server = http.createServer((req, res) => {
if (req.url === "/api") {
const data = { name: "John", age: 30 };
res.writeHead(200, { "Content-Type": "application/json" });
res.end(JSON.stringify(data));
}
});
server.listen(3000);
Content-Type to application/json and use JSON.stringify().
How to serve HTML files using Node.js HTTP server?
const http = require("http");
const fs = require("fs");
const server = http.createServer((req, res) => {
fs.readFile("index.html", (err, data) => {
if (err) {
res.writeHead(500);
res.end("Error loading file");
} else {
res.writeHead(200, { "Content-Type": "text/html" });
res.end(data);
}
});
});
server.listen(3000);
fs.readFile to load HTML files and return them in the response. Similar Reads
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