A formal definition of RESTful semantic web services

Abstract

In this article a formal model applying REST architectural principles to the description of semantic web services is introduced, including the discussion of its syntax and operational semantics. RESTful semantic resources are described using the concept of tuple spaces being manipulated by HTTP methods that are related to classical tuple space operations. On the other hand, RESTful resources creation, destruction and other dynamic aspects of distributed HTTP computations involving coordination between HTTP agents and services are modeled using process calculus style named channels and message passing mechanisms. The resulting model allows for a complete and rigorous description of resource based web systems, where agents taking part in a computation publish data encoded according to semantic standards through public triple repositories identified by well known URIs. The model can be used to describe complex interaction scenarios where coordination and composition of resources are required. One of such scenarios taken from the literature about web services choreography is analyzed from the point of view of the proposed model. Finally, possible extensions to the formalism, such as the inclusion of a description logics based type system associated to the semantic resources or possible extensions to HTTP operations are briefly explored.