const express = require('express');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');

const app = express();
const port = 3000;

// Middleware
app.use(bodyParser.json());

// Connect to MongoDB
mongoose.connect('mongodb://localhost:27017/authdb', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

// Routes
app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});
const mongoose = require('mongoose');
const bcrypt = require('bcryptjs');

const userSchema = new mongoose.Schema({
  username: {
    type: String,
    required: true,
    unique: true,
  },
  password: {
    type: String,
    required: true,
  },
});

// Pre-save hook to hash passwords
userSchema.pre('save', async function (next) {
  if (this.isModified('password') || this.isNew) {
    const salt = await bcrypt.genSalt(10);
    this.password = await bcrypt.hash(this.password, salt);
  }
  next();
});

userSchema.methods.comparePassword = function (password) {
  return bcrypt.compare(password, this.password);
};

module.exports = mongoose.model('User', userSchema);
const express = require('express');
const jwt = require('jsonwebtoken');
const User = require('../models/User');

const router = express.Router();
const secretKey = 'yourSecretKey';

// Signup
router.post('/signup', async (req, res) => {
  try {
    const { username, password } = req.body;
    const user = new User({ username, password });
    await user.save();
    res.status(201).send('User created');
  } catch (err) {
    res.status(400).send(err);
  }
});

// Login
router.post('/login', async (req, res) => {
  try {
    const { username, password } = req.body;
    const user = await User.findOne({ username });
    if (!user || !(await user.comparePassword(password))) {
      return res.status(401).send('Invalid credentials');
    }

    const token = jwt.sign({ id: user._id }, secretKey, { expiresIn: '1h' });
    res.status(200).json({ token });
  } catch (err) {
    res.status(400).send(err);
  }
});

// User Details (protected)
router.get('/me', verifyToken, async (req, res) => {
  try {
    const user = await User.findById(req.userId).select('-password');
    res.status(200).json(user);
  } catch (err) {
    res.status(400).send(err);
  }
});

module.exports = router;
const jwt = require('jsonwebtoken');
const secretKey = 'yourSecretKey';

const verifyToken = (req, res, next) => {
  const token = req.headers['authorization'];
  if (!token) return res.status(403).send('Token is required');

  jwt.verify(token, secretKey, (err, decoded) => {
    if (err) return res.status(401).send('Invalid token');
    req.userId = decoded.id;
    next();
  });
};

module.exports = verifyToken;
const express = require('express');
const bodyParser = require('body-parser');
const mongoose = require('mongoose');
const authRoutes = require('./routes/auth');
const verifyToken = require('./middleware/auth');

const app = express();
const port = 3000;

// Middleware
app.use(bodyParser.json());

// Connect to MongoDB
mongoose.connect('mongodb://localhost:27017/authdb', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

// Routes
app.use('/api/auth', authRoutes);

// Protected Route Example
app.get('/api/protected', verifyToken, (req, res) => {
  res.send('This is a protected route');
});

app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});