Now departing Grid. Next stop, Web.

Via Savas (subscribed!), I’m following a lot of the discussion regarding the recent Grid/Web-services “unification” specs, WSRF. Good stuff! These folks are even closer to having their Web gestalt moment I believe, as they’re now talking about “stateful resources” (now where have I heard of those before?) in the context of integrating two different systems, the Grid and Web services. Rock on! I think I’ll sign up to a mailing list or two.

While following those links, I ran across a proposal by Savas and his group called WS-GAF, a sort of accidental precursor to parts of WSRF. It mentioned REST;

There have been proposals for naming and uniformly providing access to resources, like the REpresentational State Transfer (REST) [2] model. However, since REST depends on HTTP it is protocol specific and hence unsuitable for heterogeneous systems like the Grid.

First, I just want to say that I think it’s wonderful that REST was even mentioned in the context of the Grid. Most folks think it’s still just for humans and browsers and HTML. Very refreshing. Now for the bad news (come on, you knew it was coming … 8-). REST does not depend on HTTP at all. It is an architectural style, and therefore prescribes no specific implementation, it just describes the constraints that one uses when designing a RESTful system. You could run out and build one that didn’t use any existing technology, if you wanted to.

Savas might be interested in a response of mine to Werner Vogels regarding his Web services are not distributed objects paper.

WS-GAF still uses URIs, which is great. Here’s an example of one;

urn:dais:dataset:b4136aa4-2d11-42bd-aa61-8e8aa5223211

This is wonderful, in a sense. It’s the first time I’ve seen that we’ve narrowed the whole SOA/REST/Web issue down to an issue of Web architecture, in particular, httpRange-14 (well, you have to squint a little to see why it’s really that issue – it could have been called the “uriRange” issue, i.e. what can a URI identify?).

So my claim is that WS-GAF would be far better off to identify its resources using http URIs, for the same reason that “info” scheme users would.

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