Experiment 8: ExpressJS – Cookies, Sessions, Authentication

Write a program for session management using cookies and sessions.



npm init -y
npm install express cookie-parser express-session

app.js

const express = require("express");
const cookieParser = require("cookie-parser");
const session = require("express-session");

const app = express();

// Middleware
app.use(cookieParser());
app.use(express.urlencoded({ extended: true }));

// Session middleware
app.use(
  session({
    secret: "mySecretKey",
    resave: false,
    saveUninitialized: true,
    cookie: { maxAge: 60000 } // 1 minute
  })
);

// Home page
app.get("/", (req, res) => {
  res.send(`
    <h2>Session Management Demo</h2>
    <a href="/set-cookie">Set Cookie</a><br><br>
    <a href="/get-cookie">Get Cookie</a><br><br>
    <a href="/set-session">Set Session</a><br><br>
    <a href="/get-session">Get Session</a><br><br>
    <a href="/destroy-session">Destroy Session</a>
  `);
});


// ------------------ COOKIE SECTION ------------------

// Set cookie
app.get("/set-cookie", (req, res) => {
  res.cookie("username", "StudentUser", { maxAge: 60000 });
  res.send("Cookie has been set");
});

// Get cookie
app.get("/get-cookie", (req, res) => {
  const user = req.cookies.username;
  res.send("Stored Cookie Value: " + user);
});


// ------------------ SESSION SECTION ------------------

// Set session
app.get("/set-session", (req, res) => {
  req.session.user = "SessionUser";
  res.send("Session value has been set");
});

// Get session
app.get("/get-session", (req, res) => {
  if (req.session.user) {
    res.send("Session Value: " + req.session.user);
  } else {
    res.send("No session found");
  }
});

// Destroy session
app.get("/destroy-session", (req, res) => {
  req.session.destroy();
  res.send("Session destroyed");
});

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

Output:



 Write a program for user authentication 


1. Install Required Packages

npm init -y
npm install express express-session


2. Program: User Authentication using Express.js

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

const app = express();

// Middleware
app.use(express.urlencoded({ extended: true }));

app.use(
  session({
    secret: "authSecret",
    resave: false,
    saveUninitialized: true
  })
);

// Dummy user credentials
const USER = {
  username: "admin",
  password: "12345"
};

// Home Page
app.get("/", (req, res) => {
  res.send(`
    <h2>User Authentication Demo</h2>
    <a href="/login">Login</a> |
    <a href="/dashboard">Dashboard</a> |
    <a href="/logout">Logout</a>
  `);
});

// Login Page
app.get("/login", (req, res) => {
  res.send(`
    <h3>Login</h3>
    <form method="POST" action="/login">
      Username: <input type="text" name="username" /><br><br>
      Password: <input type="password" name="password" /><br><br>
      <button type="submit">Login</button>
    </form>
  `);
});

// Login Logic
app.post("/login", (req, res) => {
  const { username, password } = req.body;

  if (username === USER.username && password === USER.password) {
    req.session.user = username;
    res.redirect("/dashboard");
  } else {
    res.send("Invalid Username or Password");
  }
});

// Protected Dashboard
app.get("/dashboard", (req, res) => {
  if (req.session.user) {
    res.send(`
      <h2>Welcome ${req.session.user}</h2>
      <p>You are logged in</p>
      <a href="/logout">Logout</a>
    `);
  } else {
    res.redirect("/login");
  }
});

// Logout
app.get("/logout", (req, res) => {
  req.session.destroy();
  res.send("You are logged out");
});

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

3. How Authentication Works (Simple)

  1. User enters username & password

  2. Server checks credentials

  3. If valid → session is created

  4. Protected pages check session

  5. Logout destroys the session

4. Output Flow

  1. Open http://localhost:3000

  2. Click Login

  3. Enter:

    Username: admin
Password: 12345

  4. Access Dashboard

  5. Logout


Output:

User Authentication Demo

Login | Dashboard | Logout

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