PHP Web Services, 2nd Edition

Chapter 8. REST

REST stands for REpresentational State Transfer, and in contrast to protocols such as SOAP or XML-RPC, it is more a philosophy or a set of principles than a protocol in its own right. REST is a set of ideas about how data can be transferred elegantly, and although it’s not tied to HTTP, it is discussed here in the context of HTTP. REST takes great advantage of the features of HTTP, so the earlier chapters covering this and the more detailed topics of headers and verbs can all come together to support a good knowledge of REST.

In a RESTful service, four HTTP verbs are used to provide a basic set of CRUD (Create, Read, Update, Delete) functionality: POST, GET, PUT, and DELETE. It is also possible to see implementations of other verbs in RESTful services, such as PATCH to allow partial update of a record, but the basic four provide the platform of a RESTful service.

The operations are applied to resources in a system. The “Representational State Transfer” name is accurate; RESTful services deal in transferring representations of resources. A representation might be JSON or XML, or indeed anything else. So what is a resource? Well, everything is. Each individual data record in a system is a resource. At the first stage of API design, a starting point could be to consider each database row as an individual resource. Think of an imaginary blogging system as an example: resources might be posts, categories, and authors. Every resource has a URI, which is the unique identifier ...