Session in PHP with an example

Sessions in PHP are a mechanism to store user-specific information across multiple web pages. This is useful when you need to track a user's state within your application, such as keeping items in a shopping cart or remembering their login status.

Here's how sessions work in PHP:

Starting a Session: You initiate a session using the session_start() function. This function either retrieves an existing session associated with the user (identified by a session ID) or creates a new session if one doesn't exist.
Storing Session Data: You can store data related to the user in the session using the associative array $_SESSION. This array acts like a container where you can assign key-value pairs. For example, $_SESSION["username"] = "johnDoe"; stores the username "johnDoe" under the key "username".
Accessing Session Data: On subsequent pages within the same session, you can access the stored data using the $_SESSION array. The values can be used for various purposes, like personalizing content or remembering user preferences.
Destroying Sessions: Sessions can expire automatically when the user closes the browser or after a specific period of inactivity. You can also explicitly destroy a session using the session_destroy() function.

Here's an example to illustrate these concepts:

login.php:

<?php
session_start();

if (isset($_POST['username']) && isset($_POST['password'])) {
  // Simulate successful login (replace with actual authentication logic)
  $_SESSION['username'] = $_POST['username'];
  header('Location: profile.php');
  exit;
}
?>

<!DOCTYPE html>
<html>
<body>
<form method="post">
  Username: <input type="text" name="username" required><br>
  Password: <input type="password" name="password" required><br>
  <button type="submit">Login</button>
</form>
</body>
</html>

profile.php:

<?php
session_start();

if (!isset($_SESSION['username'])) {
  header('Location: login.php');
  exit;
}

$username = $_SESSION['username'];
?>

<!DOCTYPE html>
<html>
<body>
  Welcome, <?php echo $username; ?>! This is your profile page.
</body>
</html>

In this example:

login.php checks for submitted login credentials. If valid (replace with actual authentication), it stores the username in the session ($_SESSION['username']) and redirects to profile.php.
profile.php starts the session and checks if a username is present in the session. If not, it redirects back to the login page. If a username exists, it welcomes the user by name using the retrieved session data.

This is a basic example of using sessions in PHP. You can extend this concept to store various user-specific information and manage user state across your web application. Remember to always implement proper security measures when handling user data in sessions.

Blog

Session in PHP with an example

ncutixavier

Join Our Newsletter. No Spam, Only the good stuff.

Related