How can PHP developers prevent unauthorized access to scripts when passing values through URLs?

To prevent unauthorized access to scripts when passing values through URLs in PHP, developers can implement input validation and sanitization to ensure that only expected and safe values are accepted. Additionally, developers can use session variables to store sensitive data instead of passing them through URLs, and implement proper access control mechanisms to restrict access to certain scripts based on user permissions. 

// Example of input validation and sanitization to prevent unauthorized access
$user_id = isset($_GET['user_id']) ? filter_var($_GET['user_id'], FILTER_SANITIZE_NUMBER_INT) : null;

if ($user_id) {
    // Proceed with the script
} else {
    // Redirect or display an error message
    header('Location: error.php');
    exit();
}

Keywords

PHP URL parameters security authentication access control

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