Are there best practices for handling form submissions in PHP to prevent issues related to reloading and multiple submissions?

Issue: To prevent issues related to reloading and multiple submissions of a form in PHP, it is recommended to use techniques like redirect-after-post, token-based validation, and disabling form resubmission. Code snippet: 

<?php
session_start();

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    if (!isset($_POST['token']) || $_POST['token'] !== $_SESSION['token']) {
        // Invalid token, handle error or redirect
    }

    // Process form submission

    // Unset token to prevent multiple submissions
    unset($_SESSION['token']);

    // Redirect to prevent form resubmission
    header('Location: success.php');
    exit;
}

// Generate unique token for each form submission
$token = md5(uniqid(rand(), true));
$_SESSION['token'] = $token;
?>

<form method="post" action="">
    <!-- Form fields go here -->
    <input type="hidden" name="token" value="<?php echo $token; ?>">
    <input type="submit" value="Submit">
</form>

Keywords

form submissions PHP reloading multiple submissions validation

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