What steps should be taken to ensure the PHP code for the shipping module is secure and follows coding standards?

To ensure the PHP code for the shipping module is secure and follows coding standards, the following steps should be taken: 1. Sanitize user input to prevent SQL injection and cross-site scripting attacks. 2. Use prepared statements or parameterized queries when interacting with the database. 3. Implement proper error handling to prevent sensitive information leakage. Example PHP code snippet:

// Sanitize user input
$shipping_method = filter_input(INPUT_POST, 'shipping_method', FILTER_SANITIZE_STRING);

// Prepare and execute a parameterized query
$stmt = $pdo->prepare("SELECT * FROM shipping_methods WHERE method = :method");
$stmt->bindParam(':method', $shipping_method);
$stmt->execute();

// Proper error handling
if($stmt->rowCount() > 0) {
    // Process shipping method
} else {
    // Handle error
}