Towards an Interpretation Framework for Assessing Interface Uniformity in REST

Interface uniformity is regarded as one of the most distinctive features of the REST architectural style among other network-based styles, because of the specific set of restrictions it imposes on the behavior paradigms of interacting components. However, in practice conforming to the REST's uniform interface constraint in Web-based services most often proves to be a difficult task, as identified by a number of researchers and practitioners. This implementation and conformance difficulty can be partly attributed to the lack of a systematic conceptual framework that could be used to interpret abstract architectural restrictions of interface uniformity to practical design decisions and strategies being generalized as interface design criteria. These criteria could be then mapped to domain-specific techniques that provide the context for guiding and/or examining the level of uniformity of a REST-based API. In this paper, we discuss such a conceptual framework and a collection of criteria that can be used to assess in a practical way as to whether a specific REST-based API conforms to the uniform interface constraint. As a proof of concept, we evaluated the proposed framework and its associated methodology by applying it to a collection of indicative public Web service APIs.