Writing an endpoint

Endpoint services are registered with the plone:service ZCML tags:

<plone:service
  method="GET"
  factory=".get.BreadcrumbsGet"
  for="zope.interface.Interface"
  permission="zope2.View"
  name="@breadcrumbs"
  />

They are similar in registration with the more simple BrowserViews, except you can also set the HTTP verb that they will be used for.

For the python implementation:

from plone.restapi.services import Service

class BreadcrumbsGet(Service):
    def reply(self):
        # ... pseudocode
        return extract_something_from(self.context)