Node.js and Express session handling - Back button problem

1. Install the required packages:

npm install express express-session

1. Import the packages in your Node.js application:

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

1. Set up the session middleware with the necessary configurations:

app.use(session({
  secret: 'your-secret-key',
  resave: false,
  saveUninitialized: true,
  cookie: { secure: false } // Adjust as needed based on your deployment environment
}));

1. Implement a middleware to check for session existence and handle redirection if needed:

app.use((req, res, next) => {
  if (!req.session.user && req.path !== '/login') {
    res.redirect('/login');
  } else {
    next();
  }
});

1. Create a route for the login page:

app.get('/login', (req, res) => {
  res.render('login'); // Adjust this based on your template engine or rendering method
});

1. Handle login POST request to set the session:

app.post('/login', (req, res) => {
  // Authenticate user (replace this with your authentication logic)
  const { username, password } = req.body;

  // Example: check username and password
  if (username === 'your_username' && password === 'your_password') {
    req.session.user = username;
    res.redirect('/');
  } else {
    res.redirect('/login');
  }
});

1. Implement a route for the main page, where session is required:

app.get('/', (req, res) => {
  res.send(`Welcome, ${req.session.user}!`);
});

1. Add a logout route to clear the session:

app.get('/logout', (req, res) => {
  req.session.destroy(err => {
    if (err) {
      console.error('Error destroying session:', err);
    }
    res.redirect('/login');
  });
});

1. Handle the back button issue by setting appropriate headers:

app.use((req, res, next) => {
  res.header('Cache-Control', 'private, no-cache, no-store, must-revalidate');
  res.header('Expires', '-1');
  res.header('Pragma', 'no-cache');
  next();
});

1. Start the Express server:

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});