We will create the iap_isbn_service module. This service module will handle customer IAP requests. Customers will send the book info requests with the ISBN numbers. The service module will capture the credit from the customer account and return information like the name, author, and cover image.

To provide easy understanding, we will develop a service module by splitting it into two recipes. In this recipe, we will create a basic module that creates a table for the book's information. Upon a customer request, the service provider will return the book information by searching in this table. In the next recipe, we will add the second part of the service module; in that module, we will add the code to capture the credits.