You process Apple Pay transactions in three phases:
Preparation: Create a payment request and populate it with payment information and details about the product the user is purchasing.
Payment sheet interaction: Respond to user interactions with the payment sheet (such as changes to the shipping address or the desired shipping method) through the methods of the
PKPaymentAuthorizationViewControllerDelegate
protocol.Payment processing: Process the Apple Pay transaction on the user's device and your own servers through the API provided by your payment gateway and HTTP requests to your order processing web app.
Earlier chapters showed the workflows you use to interact with the major actors in Apple Pay transactions. This chapter provides helpful information on the classes, methods, and properties of the Apple Pay API that you must become familiar with to use it effectively. However, when you need even more detailed information, you should consult the Apple developer...