यह example दिखाता है कि कैसे Node.js में एक HTTP server बनाया जाए और fs module का इस्तेमाल करके file read/write किया जाए।
const http = require('http');
const fs = require('fs');
// Create HTTP Server
const server = http.createServer((req, res) => {
if (req.url === '/write') {
// Write to file
fs.writeFile('example.txt', 'Hello from Node.js!', (err) => {
if (err) {
res.writeHead(500, { 'Content-Type': 'text/plain' });
return res.end('❌ Error writing file.');
}
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('✅ File written successfully.');
});
} else if (req.url === '/read') {
// Read file
fs.readFile('example.txt', 'utf8', (err, data) => {
if (err) {
res.writeHead(500, { 'Content-Type': 'text/plain' });
return res.end('❌ Error reading file.');
}
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end(`📄 File Content: ${data}`);
});
} else {
// Default Route
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('Welcome! Use /write to create a file and /read to read it.');
}
});
// Start Server
const PORT = 3000;
server.listen(PORT, () => {
console.log(`🚀 Server running at http://localhost:${PORT}`);
});
project-folder/
│
├── server.js
└── pages/
├── header.html
├── footer.html
├── index.html
├── about.html
├── contact.html
└── style.css
const http = require('http');
const fs = require('fs');
const path = require('path');
const PORT = 3000;
http.createServer((req, res) => {
let filePath = '';
let contentType = 'text/html';
// Common header and footer
const headerHTML = fs.readFileSync(path.join(__dirname, 'pages', 'header.html'), 'utf-8');
const footerHTML = fs.readFileSync(path.join(__dirname, 'pages', 'footer.html'), 'utf-8');
// Routing
if (req.url === '/' || req.url === '/index') {
filePath = path.join(__dirname, 'pages', 'index.html');
}
else if (req.url === '/about') {
filePath = path.join(__dirname, 'pages', 'about.html');
}
else if (req.url === '/contact') {
filePath = path.join(__dirname, 'pages', 'contact.html');
}
else if (req.url === '/style.css') {
filePath = path.join(__dirname, 'pages', 'style.css');
contentType = 'text/css';
}
else {
res.writeHead(404, { 'Content-Type': 'text/plain' });
res.end('404 Page Not Found');
return;
}
// Read and send the file
fs.readFile(filePath, 'utf-8', (err, data) => {
if (err) {
res.writeHead(500, { 'Content-Type': 'text/plain' });
res.end('Internal Server Error');
} else {
res.writeHead(200, { 'Content-Type': contentType });
if (contentType === 'text/html') {
res.write(headerHTML + data + footerHTML);
} else {
res.write(data);
}
res.end();
}
});
}).listen(PORT, () => {
console.log(`Server running at http://localhost:${PORT}`);
});
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>My Website</title>
<link rel="stylesheet" href="/style.css">
</head>
<body>
<header>
<h1>My Node.js Website</h1>
<nav>
<a href="/">Home</a> |
<a href="/about">About</a> |
<a href="/contact">Contact</a>
</nav>
</header>
<hr> <hr>
<footer>
<p>© 2025 My Website. All Rights Reserved.</p>
</footer>
</body>
</html><main>
<h2>Welcome to the Home Page</h2>
<p>This is the homepage of our simple Node.js website.</p>
</main><main>
<h2>About Us</h2>
<p>We are learning Node.js server-side rendering with static files.</p>
</main><main>
<h2>Contact Us</h2>
<p>Email: [email protected]</p>
</main>body {
font-family: Arial, sans-serif;
margin: 20px;
background: #f2f2f2;
}
header, footer {
background: #333;
color: white;
padding: 10px;
}
header a {
color: yellow;
text-decoration: none;
margin: 0 5px;
}
header a:hover {
text-decoration: underline;
}
main {
padding: 10px;
background: white;
border-radius: 5px;
}
node server.js
npm install -g nodemon nodemon server.js| Error Code | Meaning | When It Happens |
|---|---|---|
| ENOENT | No such file or directory | Jab file/directory exist nahi karti. |
| EACCES | Permission denied | Jab file/directory par access permission nahi hota. |
| EEXIST | File already exists | Jab file/directory create karte time wo already exist kare. |
| ENOTDIR | Not a directory | Jab path directory hona chahiye par file nikle. |
| EISDIR | Is a directory | Jab path file hona chahiye par directory ho. |
| EMFILE | Too many open files | Jab ek time par system me zyada files open ho jati hain. |
| EBADF | Bad file descriptor | Jab galat file descriptor ka use hota hai. |
| Error Code | Meaning | When It Happens |
|---|---|---|
| EADDRINUSE | Address already in use | Jab server ka port already kisi aur process dwara use ho. |
| ECONNREFUSED | Connection refused | Jab server request accept nahi karta. |
| ECONNRESET | Connection reset by peer | Jab connection abruptly close ho jata hai (server ya client). |
| ETIMEDOUT | Connection timed out | Jab network request ka response time se nahi milta. |
| EHOSTUNREACH | Host unreachable | Jab destination host network me available nahi hai. |
| ENETUNREACH | Network unreachable | Jab destination network tak pahunch nahi ho rahi. |
| Error Code | Meaning | When It Happens |
|---|---|---|
| ENOMEM | Not enough memory | Jab system memory khatam ho jaye. |
| EFAULT | Bad address | Jab invalid memory address access hota hai. |
| ESRCH | No such process | Jab diye gaye PID ka process exist nahi karta. |
| EPIPE | Broken pipe | Jab stream close hone ke baad usme likhne ki koshish ho. |
| EINVAL | Invalid argument | Jab kisi function ko galat argument diya jata hai. |
| EPERM | Operation not permitted | Jab operation ke liye permission nahi hai. |
Node.js में errors को handle करने के लिए आपको try...catch blocks (async/await के साथ) या callback में error parameter check करना होता है।
const fs = require('fs');
try {
fs.readFileSync('data.txt', 'utf8');
console.log('File read successfully');
} catch (err) {
if (err.code === 'ENOENT') {
console.error('❌ File not found. Please check the file path.');
} else if (err.code === 'EACCES') {
console.error('❌ Permission denied. Please check file permissions.');
} else {
console.error('⚠️ An unexpected error occurred:', err);
}
}const http = require('http');
const req = http.get('http://localhost:5000', (res) => {
console.log(`✅ Status Code: ${res.statusCode}`);
});
req.on('error', (err) => {
if (err.code === 'ECONNREFUSED') {
console.error('❌ Connection refused. Is the server running?');
} else if (err.code === 'ETIMEDOUT') {
console.error('❌ Request timed out.');
} else {
console.error('⚠️ Network error:', err);
}
});try {
process.kill(99999); // Invalid PID
} catch (err) {
if (err.code === 'ESRCH') {
console.error('❌ Process not found.');
} else if (err.code === 'EPERM') {
console.error('❌ Permission denied to kill the process.');
} else {
console.error('⚠️ System error:', err);
}
}