I have a site for a client who bakes and sells pizza. When a customer adds pizzas to the cart and then tries to checkout, and checks delivery, only a array of certain zip/post codes are accepted. However, on checkout you can now add any zip/post code. The order is passed anyway and no errors.
I've added my custom shipment class to functions.php in my theme and it looks like this: http://pastebin.com/08JvxAzg
I've copied a lot of code from Local Delivery, which comes with WooCommerce.
Is there another way of checking these codes and make sure that the customer has inputed anyone of them?