Transformation of REST API to GraphQL for OpenTOSCA

Abstract

Software has become ubiquitous in our lives delivering a diversity of functionality. These software applications may have diverse development backgrounds but they need to interact between each other for many reasons. One way to make software communicate between each other is using Application Programming Interfaces (APIs). Therefore, APIs play an important role in the design of application software architectures. Moreover, the design of these software architectures can be described by the architectural style residing behind it. Representational State Transfer (REST) is a well known architectural style that has been used as a guide to the design and development of the architecture of modern web. For simplicity reasons, REST APIs have been adored by most software developers compared to all its previous approaches. But there is concern over its effect on performance when the size of the applications on the client side grows (e.g. multiple REST calls).An alternative approach is needed to prevent or minimize these negative effects. In this research, Graph Query Language (GraphQL) is considered as an alternative for REST API. Furthermore, we developed a generic concept for the transformation of REST API to GraphQL. We also validated our concepts by prototypical implementations.