XML News from Tuesday, August 23, 2005

The W3C Web Services Addressing Working Group has posted the candidate recommendations of Web Services Addressing 1.0 Core and Web Services Addressing - SOAP Binding. The core spec defines abstract generic extensions to the Infoset for endpoint references and message addressing properties. The binding spec describes how the abstract properties defined in the core spec is implemented in SOAP. These specs are seeing some serious pushback within the W3C. The problem is that there already is an addressing system for the Web. It's called the URI, and it's not at all clear that web services addressing does anything beyond URIs do except add complexity. In fact, it's pretty clear that it doesn't do anything except add complexity.

Here's the problem. Web Services Addressing "defines two constructs, message addressing properties and endpoint references, that normalize the information typically provided by transport protocols and messaging systems in a way that is independent of any particular transport or messaging system." In other words this is another example of the excessive genericity problem, just like DOM, and remember how well that worked. One of the big fundamental problems with DOM was that they tried to develop an architecture that could work for all conceivable programming languages; but developers don't want and don't need an API for all programming languages. they want an API that's tailored to their own programming language. This is why language-specific libraries like XOM and Amara are so much easier to use and more productive than DOM.

Web Services Addressing is trying to define an addressing scheme that can work over HTTP, SMTP, FTP, and any other protocol you can imagine. However, each of these protocols already have their own addressing systems. Developers working with these protocols don't want and don't need a different addressing system that's marginally more compatible with some protocol they're not using in exchange for substantially less compatibility with the protocol they are using. Besides nobody's actually doing web services over anything except HTTP anyway. Doesn't it just make more sense to use the well understood, already implemented debugged HTTP architecture for this instead of inventing something new?