Now that we have a basic understanding of how to use the Magento Core API, we can proceed to extend and add our custom functionality. In order to add new API functionality, we have to modify/create the following files:
wsdl.xmlapi.xmlapi.php
In order to make our registries accessible for third-party systems, we need to create and expose the following functions
giftregistry_registry.list: This retrieves a list of all the registry IDs; it takes an optional customer ID parametergiftregistry_registry.info: This retrieves all the registry information; it takes a required registry_id parametergiftregistry_item.list: This retrieves a list of all the registry item IDs associated with a registry; it takes a requiredregistry_idparametergiftregistry_item.info: This retrieves the product and detailed information of a registry item; it takes a requireditem_idparameter