Inferring Data Contract for Web-Based API

Web-based API is a new trend for publishing services. To correctly use the API, developers should follow certain service specifications. Data contract is a service specification to express the constraints over the data model used in the APIs. Data contracts, however are not always readily available in a formalized format if not undocumented at all. In this paper, we present an approach to infer formal data contracts for Web-based API. The approach integrates information of the parameters, error messages and testing result of Web-based API. We demonstrate how this approach infers complicated data preconditions for Web-based API in the real-world Web API platforms.