Autonomous composition and execution of REST APIs for smart sensors

Autonomous services discovery, composition and execution is an important problem in the Machine-to-Machine field. Achieving this objective requires addressing several issues: a) how to describe in a machine-understandable format which operations and functionalities an object is able to perform; b) how to represent the interfaces in unambiguous way and allow two or more machines to understand the data exchanged with each other; c) how to make a machine able to aggregate services in order to execute a specific task. Narrowing the domain just to REST APIs, we propose to semantically describe APIs (exposed by objects or web servers) using RESTdesc descriptions and to use JSON-LD as data exchange format. In order to illustrate the straightforward services composition and invocation process, we have implemented a smart client able to generate and execute plans (sequences of HTTP requests) that satisfy the set of operations which should be done for ensuring ideal environmental conditions to plants in a garden.