Node.js va Express.js: To'liq qo'llanma

Kirish

Node.js va Express.js zamonaviy web ilovalarning backend qismini yaratish uchun eng mashhur texnologiyalardan biri. Ushbu maqolada siz noldan boshlab to'liq ishlaydigan REST API yaratishni o'rganasiz.

1. Node.js nima?

Node.js - bu Chrome V8 JavaScript engine'ga asoslangan runtime environment bo'lib, JavaScript'ni serverda ishlatish imkonini beradi.

Node.js'ning asosiy xususiyatlari:

• Non-blocking I/O: Asinxron operatsiyalar tufayli yuqori performance
• Event-driven: Event loop mexanizmi orqali ishlaydi
• Single-threaded: Bitta thread'da ishlaydi, lekin ko'p so'rovlarni bir vaqtda boshqaradi
• NPM: 2 million+ paketlar bilan eng katta ekotizim

Node.js o'rnatish

# Windows/Mac/Linux uchun nodejs.org'dan yuklab oling

# Versiyani tekshirish
node --version
npm --version

2. Express.js bilan boshlash

Express.js - Node.js uchun minimal va moslashuvchan web framework.

Loyiha yaratish

# Yangi papka yaratish
mkdir my-api
cd my-api

# package.json yaratish
npm init -y

# Express o'rnatish
npm install express

# Development uchun nodemon
npm install --save-dev nodemon

Birinchi server

// server.js
const express = require('express');
const app = express();
const PORT = 3000;

// Middleware - JSON ma'lumotlarni qabul qilish
app.use(express.json());

// Route - GET /
app.get('/', (req, res) => {
    res.json({ message: 'API ishlayapti!' });
});

// Serverni ishga tushirish
app.listen(PORT, () => {
    console.log(`Server ${PORT}-portda ishlamoqda`);
});

Serverni ishga tushirish

# Oddiy usul
node server.js

# Nodemon bilan (avtomatik restart)
npx nodemon server.js

3. REST API yaratish

CRUD (Create, Read, Update, Delete) operatsiyalarini qo'llab-quvvatlaydigan users API yaratamiz.

// server.js
const express = require('express');
const app = express();
const PORT = 3000;

app.use(express.json());

// Ma'lumotlar bazasi (demo uchun array)
let users = [
    { id: 1, name: 'Ali', email: 'ali@example.com' },
    { id: 2, name: 'Vali', email: 'vali@example.com' }
];

// GET - Barcha foydalanuvchilar
app.get('/api/users', (req, res) => {
    res.json(users);
});

// GET - Bitta foydalanuvchi
app.get('/api/users/:id', (req, res) => {
    const user = users.find(u => u.id === parseInt(req.params.id));

    if (!user) {
        return res.status(404).json({ message: 'Foydalanuvchi topilmadi' });
    }

    res.json(user);
});

// POST - Yangi foydalanuvchi
app.post('/api/users', (req, res) => {
    const { name, email } = req.body;

    // Validation
    if (!name || !email) {
        return res.status(400).json({ message: 'Name va email majburiy' });
    }

    const newUser = {
        id: users.length + 1,
        name,
        email
    };

    users.push(newUser);
    res.status(201).json(newUser);
});

// PUT - Foydalanuvchini yangilash
app.put('/api/users/:id', (req, res) => {
    const user = users.find(u => u.id === parseInt(req.params.id));

    if (!user) {
        return res.status(404).json({ message: 'Foydalanuvchi topilmadi' });
    }

    user.name = req.body.name || user.name;
    user.email = req.body.email || user.email;

    res.json(user);
});

// DELETE - Foydalanuvchini o'chirish
app.delete('/api/users/:id', (req, res) => {
    const index = users.findIndex(u => u.id === parseInt(req.params.id));

    if (index === -1) {
        return res.status(404).json({ message: 'Foydalanuvchi topilmadi' });
    }

    users.splice(index, 1);
    res.json({ message: 'Foydalanuvchi o\'chirildi' });
});

app.listen(PORT, () => {
    console.log(`Server ${PORT}-portda ishlamoqda`);
});

4. Middleware

Middleware - bu request va response o'rtasida bajariladigan funksiyalar.

Custom Logger Middleware

// Logger middleware
const logger = (req, res, next) => {
    console.log(`${req.method} ${req.url} - ${new Date().toISOString()}`);
    next(); // Keyingi middleware'ga o'tish
};

app.use(logger);

Authentication Middleware

const authMiddleware = (req, res, next) => {
    const token = req.headers['authorization'];

    if (!token) {
        return res.status(401).json({ message: 'Token yo\'q' });
    }

    // Token tekshirish (demo)
    if (token !== 'Bearer my-secret-token') {
        return res.status(403).json({ message: 'Noto\'g\'ri token' });
    }

    next();
};

// Himoyalangan route
app.get('/api/protected', authMiddleware, (req, res) => {
    res.json({ message: 'Bu himoyalangan ma\'lumot' });
});

Error Handling Middleware

// Xatolarni ushlash (oxirgi middleware)
app.use((err, req, res, next) => {
    console.error(err.stack);
    res.status(500).json({
        message: 'Server xatosi',
        error: process.env.NODE_ENV === 'development' ? err.message : undefined
    });
});

5. MongoDB bilan ishlash

Real loyihalarda ma'lumotlar bazasi kerak bo'ladi. MongoDB'ni ishlatamiz.

MongoDB va Mongoose o'rnatish

npm install mongoose

MongoDB'ga ulanish

// config/database.js
const mongoose = require('mongoose');

const connectDB = async () => {
    try {
        await mongoose.connect('mongodb://localhost:27017/myapp', {
            useNewUrlParser: true,
            useUnifiedTopology: true
        });
        console.log('MongoDB\'ga ulanildi');
    } catch (error) {
        console.error('MongoDB xatosi:', error);
        process.exit(1);
    }
};

module.exports = connectDB;

User Model yaratish

// models/User.js
const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
    name: {
        type: String,
        required: [true, 'Ism majburiy'],
        trim: true
    },
    email: {
        type: String,
        required: [true, 'Email majburiy'],
        unique: true,
        lowercase: true
    },
    password: {
        type: String,
        required: [true, 'Parol majburiy'],
        minlength: 6
    },
    role: {
        type: String,
        enum: ['user', 'admin'],
        default: 'user'
    },
    createdAt: {
        type: Date,
        default: Date.now
    }
});

module.exports = mongoose.model('User', userSchema);

CRUD operatsiyalar MongoDB bilan

// routes/users.js
const express = require('express');
const router = express.Router();
const User = require('../models/User');

// Barcha foydalanuvchilar
router.get('/', async (req, res) => {
    try {
        const users = await User.find().select('-password');
        res.json(users);
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
});

// Bitta foydalanuvchi
router.get('/:id', async (req, res) => {
    try {
        const user = await User.findById(req.params.id).select('-password');

        if (!user) {
            return res.status(404).json({ message: 'Topilmadi' });
        }

        res.json(user);
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
});

// Yangi foydalanuvchi
router.post('/', async (req, res) => {
    try {
        const user = new User(req.body);
        await user.save();

        res.status(201).json(user);
    } catch (error) {
        res.status(400).json({ message: error.message });
    }
});

// Yangilash
router.put('/:id', async (req, res) => {
    try {
        const user = await User.findByIdAndUpdate(
            req.params.id,
            req.body,
            { new: true, runValidators: true }
        ).select('-password');

        if (!user) {
            return res.status(404).json({ message: 'Topilmadi' });
        }

        res.json(user);
    } catch (error) {
        res.status(400).json({ message: error.message });
    }
});

// O'chirish
router.delete('/:id', async (req, res) => {
    try {
        const user = await User.findByIdAndDelete(req.params.id);

        if (!user) {
            return res.status(404).json({ message: 'Topilmadi' });
        }

        res.json({ message: 'O\'chirildi' });
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
});

module.exports = router;

6. JWT Authentication

JSON Web Token bilan xavfsiz autentifikatsiya tizimi yaratamiz.

Kerakli paketlar

npm install jsonwebtoken bcryptjs

Auth Controller

// controllers/authController.js
const jwt = require('jsonwebtoken');
const bcrypt = require('bcryptjs');
const User = require('../models/User');

// Register
exports.register = async (req, res) => {
    try {
        const { name, email, password } = req.body;

        // Foydalanuvchi mavjudligini tekshirish
        const existingUser = await User.findOne({ email });
        if (existingUser) {
            return res.status(400).json({ message: 'Email band' });
        }

        // Parolni hash qilish
        const hashedPassword = await bcrypt.hash(password, 10);

        // Yangi foydalanuvchi
        const user = new User({
            name,
            email,
            password: hashedPassword
        });

        await user.save();

        // JWT yaratish
        const token = jwt.sign(
            { userId: user._id },
            'secret-key',
            { expiresIn: '7d' }
        );

        res.status(201).json({ token, user: { id: user._id, name, email } });
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
};

// Login
exports.login = async (req, res) => {
    try {
        const { email, password } = req.body;

        // Foydalanuvchini topish
        const user = await User.findOne({ email });
        if (!user) {
            return res.status(401).json({ message: 'Email yoki parol xato' });
        }

        // Parolni tekshirish
        const isMatch = await bcrypt.compare(password, user.password);
        if (!isMatch) {
            return res.status(401).json({ message: 'Email yoki parol xato' });
        }

        // JWT yaratish
        const token = jwt.sign(
            { userId: user._id },
            'secret-key',
            { expiresIn: '7d' }
        );

        res.json({
            token,
            user: { id: user._id, name: user.name, email: user.email }
        });
    } catch (error) {
        res.status(500).json({ message: error.message });
    }
};

Auth Middleware

// middleware/auth.js
const jwt = require('jsonwebtoken');

module.exports = (req, res, next) => {
    try {
        const token = req.headers.authorization?.split(' ')[1];

        if (!token) {
            return res.status(401).json({ message: 'Token yo\'q' });
        }

        const decoded = jwt.verify(token, 'secret-key');
        req.userId = decoded.userId;
        next();
    } catch (error) {
        res.status(401).json({ message: 'Noto\'g\'ri token' });
    }
};

7. Environment Variables

Muhim ma'lumotlarni .env faylida saqlash.

npm install dotenv

# .env
PORT=3000
MONGODB_URI=mongodb://localhost:27017/myapp
JWT_SECRET=your-secret-key-here
NODE_ENV=development

// server.js
require('dotenv').config();

const PORT = process.env.PORT || 3000;
const JWT_SECRET = process.env.JWT_SECRET;

8. Loyiha strukturasi

my-api/
├── config/
│   └── database.js
├── controllers/
│   ├── authController.js
│   └── userController.js
├── middleware/
│   ├── auth.js
│   └── errorHandler.js
├── models/
│   └── User.js
├── routes/
│   ├── auth.js
│   └── users.js
├── .env
├── .gitignore
├── package.json
└── server.js

Xulosa

Node.js va Express.js bilan professional backend yaratish uchun bu asoslar yetarli. Endi siz:

• REST API yarata olasiz
• MongoDB bilan ishlay olasiz
• JWT authentication qo'sha olasiz
• Middleware'larni tushunasiz
• Loyihani to'g'ri strukturalashni bilasiz

Keyingi bosqichlar:

• Testing (Jest, Supertest)
• Deployment (Heroku, DigitalOcean, AWS)
• GraphQL o'rganish
• Microservices arxitekturasi