News You Can Bruise for 2007 August 12

Argh. Sorry for downtime. It's all Kevin's fault. You might not be shocked to learn that nothing terribly important happened to me during the downtime.

RWS reader Scott writes, apropos Chapter 7's remake of the del.icio.us web service as a set of RESTful resources:

"Why is the recent list of bookmarks a resource? Why isn't "recent" a filter on the resource bookmarks?"

I couldn't figure out how to post a comment on Scott's weblog, so it goes here. The short answer is that it's both. "Resource" is the HTTP-level term, and "bookmark filter" is an end-user-level description of the resource.

It's legitimate and often useful to talk about /recent as a filter on the bookmarks, but that's an abstraction. All /recent is, is a URI that gives you something when you GET it. You might link to /recent, retrieve or cache a representation of it, etc. etc. It names a resource. Calling it a filter on the bookmark list is on the same level as calling it a list of recent bookmarks. It's accurate but not very precise: you're using high-level terms instead of well-defined terms like "resource". Resources are defined as part of HTTP and filters aren't.

Scott again:

How is "recent" bookmarks any different than "bookmarks for the last 10 days" or bookmarks since "9/10/2007"? I don't think anyone would argue that the last two aren't filters. But "recent" isn't any different then either of those two.

They're exactly the same. They're all resources. In chapter 7 when I mention features like date filters, I describe them in terms of end-user functionality so I use end-user-level terms like "filter", but on the level of HTTP analysis, /users/leonardr/bookmarks/?date=2007-06-01 or whatever points to a resource.

Hope this helps.