RESTful Web Services

Chapter 4. The Resource-Oriented Architecture

I’ve shown you the power of REST, but I haven’t shown you in any systematic way how that power is structured or how to expose it. In this chapter I outline a concrete RESTful architecture: the Resource-Oriented Architecture (ROA). The ROA is a way of turning a problem into a RESTful web service: an arrangement of URIs, HTTP, and XML that works like the rest of the Web, and that programmers will enjoy using.

In Chapter 1 I classified RESTful web services by their answers to two questions. These answers correspond to two of the four defining features of REST:

• The scoping information (“why should the server send this data instead of that data?”) is kept in the URI. This is the principle of addressability.

• The method information (“why should the server send this data instead of deleting it?”) is kept in the HTTP method. There are only a few HTTP methods, and everyone knows ahead of time what they do. This is the principle of the uniform interface.

In this chapter I introduce the moving parts of the Resource-Oriented Architecture: resources (of course), their names, their representations, and the links between them. I explain and promote the properties of the ROA: addressability, statelessness, connectedness, and the uniform interface. I show how the web technologies (HTTP, URIs, and XML) implement the moving parts to make the properties possible.

In the previous chapters I illustrated concepts by pointing to existing web services, like S3. I ...