What are the best practices for handling session data in PHP to maintain form state?

When handling session data in PHP to maintain form state, it is important to store form data in session variables and update them accordingly as the user interacts with the form. This ensures that the form data is retained across page loads and submissions. Additionally, it is recommended to sanitize and validate the form data before storing it in session to prevent security vulnerabilities. 

session_start();

// Check if form data is submitted
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Sanitize and validate form data
    $form_data = [
        'name' => filter_var($_POST['name'], FILTER_SANITIZE_STRING),
        'email' => filter_var($_POST['email'], FILTER_VALIDATE_EMAIL),
        // Add more form fields as needed
    ];

    // Store form data in session
    $_SESSION['form_data'] = $form_data;
}

// Retrieve form data from session
$form_data = isset($_SESSION['form_data']) ? $_SESSION['form_data'] : [];

// Display form with pre-filled data
?>
<form method="post" action="">
    <input type="text" name="name" value="<?php echo $form_data['name'] ?? ''; ?>" placeholder="Name">
    <input type="email" name="email" value="<?php echo $form_data['email'] ?? ''; ?>" placeholder="Email">
    <!-- Add more form fields as needed -->
    <button type="submit">Submit</button>
</form>

Keywords

session data form state PHP security serialization

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