Web Things, by Mark Baker

Just posted a new blog at my O’Reilly weblog about SOAPAction.

Greg Reinacker responds to the earlier discussion Jon Udell and I were having about uniform interfaces. The emphasis of his response is on my generalization post to www-ws-arch, in particular the part where I generalized from getStockQuote() to getQuote(). He may very well have a point that this step is pointless, I don’t know. But it was just an example of a step; perhaps a better example could be found. The main point of the post was the first step and the last; from the unparameterized, good-for-retrieving-one-thing-only method, to the good-for-any-safe-retrieval method.

Then, as I responded to Jon, the value of doing that is because deploying new interfaces is extremely expensive. If you’ve got an interface that can do what you need, then you’re better off using it.

Greg did have this to say in his conclusion, which I’d like to comment on;

You can retrieve anything the same way, but you can’t process it without knowing more specifically what it is.

I can’t emphasize enough how important this point is. Being able to retrieve anything is a big win. Processing it is indeed an issue, and a non-trivial one (as I just alluded to), but with Web services, you’ve got both the problem of being able to get the data and the problem of knowing how to process it. The Web solves the first problem, and that’s just with the GET method!

Michael Radwin reports from ApacheCon 2002 about Roy Fielding‘s presentation on Waka (his planned HTTP 1.1 replacement), and Web services.

There’s a lot of good stuff in Roy’s (PPT) presentation, but Michael appears to get the point Roy was making about Web services backwards. They don’t solve the N^2 problem, they are the N^2 problem. REST’s uniform interface constraint is what drives the complexity of integration to O(N).