Today, REST APIs have established as a means for realizing distributed systems and are supposed to gain even more importance in the context of Cloud Computing, Internet of Things, and Microservices. Nevertheless, many existing REST APIs are known to be not well designed, resulting in the absence of desirable non-functional properties that truly RESTful systems entail. Although existing analysis show, that many REST APIs are not fully REST compliant, it is still an open issue how to improve this deficit and where to start. In this work, we apply structural analysis of REST APIs in order to support API governance, resulting in a set of basic and aggregated metrics that characterize an API set and also guide further governance tasks. We apply the structural analysis on a set of 286 real world APIs and then demonstrate how to derive suitable metrics that represent the perceived complexity of an API, complemented and validated by a survey of developers following the AHP process. As a result, we provide effective support for API governance, helping to identify and remedy problems in APIs.

如今，REST API 已成为实现分布式系统的一种手段，并且在云计算、物联网和微服务的背景下将变得更加重要。然而，众所周知，许多现有的 REST API 设计不佳，导致缺乏真正 RESTful 系统所需的理想非功能属性。尽管现有的分析表明，许多 REST API 并不完全符合 REST 标准，但如何改善这种缺陷以及从哪里开始仍然是一个悬而未决的问题。在这项工作中，我们应用 REST API 的结构分析来支持 API 治理，从而产生一组基本和聚合的指标，这些指标表征 API 集并指导进一步的治理任务。我们对一组 286 个现实世界 API 进行结构分析，然后演示如何导出代表 API 感知复杂性的合适指标，并通过遵循 AHP 流程的开发人员调查进行补充和验证。因此，我们为 API 治理提供有效的支持，帮助识别和修复 API 中的问题。