DaveO on leaky protocol abstractions

By | 2005/04/06

Another gem from Dave;

This is the main thesis of this article, that the application layer modeling is affected by the underlying protocol.

Absolutely. I think the leaks that Dave so accurately describes there, is, largely, his fault (but a Very Good Thing! 8-). He has tried to respect the architecture of the Web in his work on Web services, and as a result, created the problems he now describes, along with everybody else who ever pushed to defend a principle or constraint of Web architecture, including myself. I was very frankly surprised that it took this long for a Web services proponent to point it out, but I’ve been doing it for a while (and long before that post – it’s just the most succinct description I could recall of the layering problems with Web services, albeit slightly different ones than Dave’s describing).

He goes on…

Another possibility is to throw out anything “extra” from the underlying protocol, that is effectively dumbing HTTP down to UDP.

Yes, that’s the only way that what most Web services proponents know “protocol independence” to mean, could be realized, and the leaky abstractions Dave speaks of, avoided.

The next sentence reads;

Web services using SOAP and WSDL 1.1 has already done that by ignoring the HTTP Operation.

Right. And as I mention in the above mentioned post, there’s more than just the operation which is ignored, including the Request-URI when using wsa:To, and the response code when assuming any response with a SOAP fault element is a fault.

Unfortunately, at that point, Dave apparently reiterates his undying faith in this beast of an architecture, and attempts to resolve this fundamental problem within it. Ouch!

There is another way; embrace the Web.

Oh, and all this reminds me that Steve Vinoski and I just had a great chat where we came to agree on what was and wasn’t desirable to do in the name of “protocol independence”.

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