1.2. Thinking in Resources

Resources are the fundamental building blocks of web-based systems, to the extent that the Web is often referred to as being “resource-oriented.” A resource is anything we expose to the Web, from a document or video clip to a business process or device. From a consumer’s point of view, a resource is anything with which that consumer interacts while progressing toward some goal. Many real-world resources might at first appear impossible to project onto the Web. However, their appearance on the Web is a result of our abstracting out their useful information aspects and presenting these aspects to the digital world. A flesh-and-blood or bricks-and-mortar resource becomes a web resource by the simple act of making the information associated with it accessible on the Web. The generality of the resource concept makes for a heterogeneous community. Almost anything can be modeled as a resource and then made available for manipulation over the network: “Roy’s dissertation,” “the movie Star Wars,” “the invoice for the books Jane just bought,” “Paul’s poker bot,” and “the HR process for dealing with new hires” all happily coexist as resources on the Web.

1.2.1. Resources and Identifiers

To use a resource we need both to be able to identify it on the network and to have some means of manipulating it. The Web provides the Uniform Resource Identifier, or URI, for just these purposes. A URI uniquely identifies a web resource, and at the same time makes it addressable, or capable of being manipulated using an application protocol such as HTTP (which is the predominant protocol on the Web). A resource’s URI distinguishes it from any other resource, and it’s through its URI that interactions with that resource take place.