Beyond SOA and REST for Distributed Application Integration

The fundamental problem of distributed application integration is reducing application coupling as much as possible while still meeting the minimum interoperability requirements. Service-oriented architecture (SOA) and representational state transfer (REST) are the most used architectural styles to deal with this problem. This chapter performs a comparative study of these styles and shows that, while both solve basic interoperability, neither of them minimizes coupling, since data description schemas are shared by the interacting applications (symmetric interoperability). SOA is oriented towards behavior (services) and REST towards state (structured resources). Services have no structure and resources have a fixed service. This chapter proposes a new architectural style, structured services, that combines the best characteristics of SOA and REST (services can have structure and resources can implement application-specific services), while using asymmetric interoperability (schema compatibility is based on structural compliance and conformance) to minimize application coupling.