What are some alternatives to using header redirection in PHP to avoid losing form data during validation?

When using header redirection in PHP to redirect after form submission, the form data will be lost if there are validation errors. To avoid losing form data during validation, one alternative is to store the form data in sessions and display error messages on the same page. 

<?php
session_start();

$errors = [];

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Validate form data
    if (/* validation fails */) {
        $errors[] = "Validation error message";
    }

    if (empty($errors)) {
        // Process form data
        // Redirect to success page
        header("Location: success.php");
        exit();
    } else {
        // Store form data in session
        $_SESSION['form_data'] = $_POST;
        $_SESSION['errors'] = $errors;
    }
}

// Display form with error messages
if (!empty($_SESSION['errors'])) {
    foreach ($_SESSION['errors'] as $error) {
        echo $error . "<br>";
    }
}

// Display form with previously submitted data
?>
<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
    <input type="text" name="name" value="<?php echo isset($_SESSION['form_data']['name']) ? $_SESSION['form_data']['name'] : ''; ?>">
    <input type="submit" value="Submit">
</form>

Related Questions