code to extend the session expiry in express nodejs

Extending session expiry in an Express app can be achieved by updating the session's expiration time each time the user makes a request. Here’s how you can implement this:

1. Using Express-Session Middleware: This approach is suitable if you are using traditional session management with express-session.

2. Using JWT: If you are using JWT for session management, you can issue a new token with an extended expiry time each time the user makes a request.

Using Express-Session Middleware

First, you need to set up the express-session middleware:

const express = require('express');
const session = require('express-session');

const app = express();

app.use(session({
  secret: 'your-secret-key',
  resave: false,
  saveUninitialized: true,
  cookie: { 
    maxAge: 30 * 60 * 1000  // Initial session expiration time (30 minutes)
  }
}));

// Middleware to extend session expiry
app.use((req, res, next) => {
  if (req.session) {
    req.session.cookie.maxAge = 30 * 60 * 1000; // Extend session by 30 minutes
  }
  next();
});

app.get('/', (req, res) => {
  if (req.session.views) {
    req.session.views++;
    res.send(`Number of views: ${req.session.views}`);
  } else {
    req.session.views = 1;
    res.send('Welcome to the session demo. Refresh!');
  }
});

app.listen(3000, () => {
  console.log('Server running on http://localhost:3000');
});

Using JWT

If you're using JWT, you will need to issue a new token with an extended expiry time each time the user makes a request:

1. Setup JWT Middleware:

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

const app = express();
const SECRET_KEY = 'your-secret-key';

app.use(bodyParser.json());

function generateToken(user) {
  return jwt.sign(user, SECRET_KEY, { expiresIn: '30m' }); // Token expires in 30 minutes
}

function verifyToken(req, res, next) {
  const token = req.headers['authorization'];
  if (!token) return res.sendStatus(403);

  jwt.verify(token, SECRET_KEY, (err, user) => {
    if (err) return res.sendStatus(403);
    req.user = user;
    next();
  });
}

// Extend token expiry middleware
app.use((req, res, next) => {
  const token = req.headers['authorization'];
  if (token) {
    jwt.verify(token, SECRET_KEY, (err, user) => {
      if (!err) {
        const newToken = generateToken({ id: user.id, username: user.username });
        res.setHeader('Authorization', newToken);
      }
    });
  }
  next();
});

app.post('/login', (req, res) => {
  const user = { id: 1, username: 'test' }; // Authenticate user
  const token = generateToken(user);
  res.json({ token });
});

app.get('/protected', verifyToken, (req, res) => {
  res.send(`Hello ${req.user.username}`);
});

app.listen(3000, () => {
  console.log('Server running on http://localhost:3000');
});

Explanation

• Express-Session Approach:

  • The maxAge property in the session cookie configuration sets the initial session expiration time.
  • The middleware checks if a session exists and then updates the session's maxAge property, effectively extending the session expiry time on each request.

• JWT Approach:

  • generateToken function creates a JWT with a specified expiry time.
  • verifyToken middleware verifies the token and attaches the user information to the request object.
  • Middleware for extending the token expiry verifies the current token and, if valid, issues a new token with an extended expiry time, setting it in the Authorization header.