My only real exposure to the ideas of REST has been through Ruby on Rails' RESTful routing. This has suited me well for the kind of CRUD-based applications I have built with Rails, but consequently my understanding of RESTfulness is somewhat limited.

Let's say we have a finite collection of Items, each of which has a unique ID, and a number of properties, such as colour, shape, and size (which might be undefined for some Items).

Items can be used by a client for a period of time, but each Item can only be used by one client at once. Access to Items is regulated by a server. Clients can request the temporary use of certain items from a server.

Usually, clients will only be interested in getting access to a number of Items with particular properties, rather than getting access to specific Items.

When a client requests use of a number of Items, the server responds with a list of IDs corresponding to the request, or with a response that says that the requested Items are not currently available or do not exist.

A client can make the following kinds of request:

• Tell me how many green triangle Items there are (in total/available).
• Give me use of 200 large red Items.
• I have finished with Items 21, 23, 23.
• Add 100 new red square Items.
• Delete 50 small green Items.
• Modify all big yellow pentagon Items to be blue.

The toy example above is like a resource allocation problem I have had to deal with recently. How should I go about thinking about it RESTfully?