How can PHP effectively handle the issue of users repeatedly clicking the submit button before the server has processed the form submission?

Issue: Users repeatedly clicking the submit button before the server processes the form submission can result in duplicate form submissions and potential data integrity issues. To prevent this, we can use a technique called "form tokenization" where a unique token is generated and submitted with the form. Upon form submission, the server checks if the token is valid before processing the request. PHP Code Snippet: 

session_start();

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    if (!isset($_SESSION['token'])) {
        $_SESSION['token'] = bin2hex(random_bytes(32));
    }

    if ($_POST['token'] == $_SESSION['token']) {
        // Process form submission
        unset($_SESSION['token']);
    } else {
        // Token mismatch, handle error
        echo 'Token mismatch, please try again.';
    }
}
?>

<form method="post">
    <input type="hidden" name="token" value="<?php echo $_SESSION['token']; ?>">
    <!-- Other form fields -->
    <button type="submit">Submit</button>
</form>

Keywords

Debounce Throttling JavaScript AJAX Form validation

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