Customize Controller from commercewebservices in SAP Commerce Cloud

Question

From what I understand, from SAP Commerce Cloud 2005 onward the way to customize the REST-endpoints within SAP Commerce Cloud for Spartacus is to use commercewebservices (non-template) and then add own occ-extensions with your REST-endpoints.

That works fine for new endpoints, but what if I want to customize an existing controller from within commercewebservices? Since I am not using the template anymore commercewebservices cannot be modified anymore. I don't see a way how I could for example customize de.hybris.platform.commercewebservices.core.v2.controller.CartsController.

Swapping out commercewebservices with your own extension generated from the template does not work since multiple OOTB (e.g. cmsocc) extensions depend on commercewebservices hence it will always be loaded and clash with our own extension derived from commercewebservices.

Customizing commercewebservices with an addOn also does not solve the problem since, as I understand, it is not possible to add your own controller and bind it to the a url-pattern already used from a controller within commercewebservices

Answer 1

If you want to override an existing API endpoint (CartsController in our case), you can do so with the @RequestMappingOverride annotation.

Using this annotation, you can "shadow" the existing request mapping of the out-of-the-box controller with your custom controller in your own OCC extension.

You can find more details and an example here:

Overriding the REST API [help.sap.com]

EDIT

And let's not forget:
All of the action happens in the facades anyway, and you can also extend the API responses without overriding the Controller using the WsDTO concept plus additional converters. (see Extending Data Objects[help.sap.com] for more details)