What are some alternative methods for handling user authentication and session management in PHP besides storing credentials in variables within the script?

Storing credentials in variables within the script is not secure as it exposes sensitive information to potential attackers. A more secure approach is to use PHP sessions to handle user authentication and session management. This involves storing user credentials securely in a database and generating a unique session ID for each user that is stored in a cookie on the client side.

// Start the session
session_start();

// Check if user is authenticated
if(isset($_SESSION['user_id'])) {
    // User is authenticated
    // Perform actions for authenticated users
} else {
    // User is not authenticated
    // Redirect to login page or display error message
}

// To authenticate a user, store user credentials in a database and validate them
// Then, set the user_id in the session
$_SESSION['user_id'] = $user_id;

// To logout a user, simply unset the user_id in the session
unset($_SESSION['user_id']);