Automated analysis of inter-parameter dependencies in web APIs

Web services often impose constraintsthat restrict the way in which two or more input parameters can be combined to form valid calls to the service, i.e. inter-parameter dependencies. Current web API specification languages like the OpenAPI Specification (OAS) pro vide no support for the formal description of such dependencies, making it hardly possible to interact with the services without human intervention. We propose specifying and automatically ana lyzing inter-parameter dependencies in web APIs. To this end, we propose a domain-specific language to describe these dependencies, a constraint programming-aided tool supporting their automated analysis, and an OAS extension integrating our approach and eas ing its adoption. Together, these contributions open a new range of possibilities in areas such as source code generation and testin

Inferring Dependency Constraints on Parameters for Web Services

Recently many popular websites such as Twitter and Flickr expose their data through web service APIs, enabling third-party organizations to develop client applications that provide functionalities beyond what the original websites offer. These client applications should follow certain constraints in order to correctly interact with the web services. One common type of such constraints is Dependency Constraints on Parameters. Given a web service operation O and its parameters Pi, Pj,…, these constraints describe the requirement on one parameter Pi that is dependent on the conditions of some other parameter(s) Pj. For example, when requesting the Twitter operation “GET statuses/user_timeline”, a user_id parameter must be provided if a screen_name parameter is not provided. Violations of such constraints can cause fatal errors or incorrect results in the client applications. However, these constraint