RADAR: RESTful Application, Dumb-Ass Recipient
PragDave: The RADAR Architecture: RESTful Application, Dumb-Ass Recipient
I’d been thinking along similar lines for a new project (which is expected to be a sort of testbed for a web services architecture). It’s a web service meant for use by third parties.
I decided, after thrashing around a bit, that machines that reside outside our firewall should be treated like end users: the interface presented is presentation logic. The fact that it is a web service is immaterial; it is distinct from the bare RESTful API to our business rules that we present to internal applications.
The application layer is what makes a process “presentable” to outsiders. It may mean consolidating several actions that are internally seen as distinct into a single operation; or adding authentication and data validation; or conforming to externally-imposed specifications (e.g., presenting an external SOAP interface); or information hiding to allow for future changes to your model and business rules.