In a previous life as a research manager in an Irish research group called TSSG I wrote a piece about semantic web for a technology column in a local paper. It’s the usual non-critical high-level look at a technology but the excitement at the promise of semantic web is very real.
However I’m less than convinced about the current web services standardisation effort. In comments to another blog I was scathingly critical of the original WS technology (SOAP & XML-RPC) and the malaise of WS standards and specs. I’ve also been keenly following the wise words of Steve Vinoski, Chief Engineer of IONA technologies, another company I used to work for. Before I digress onto another topic entirely I’m going to reiterate some of my original comments about WS standardisation, mirroring steve’s feelings about the lessons that can be learned from CORBA regarding tool & vendor support. So without wanting to offend too many of the great people involved in the process, here are my considered thoughts:
- “Web Services” is a brand name for a range of disparate and relatively unfocused technologies.
- The technology was hugely overhyped without accepted standards to back it up
- XML messages were touted as human-readable. If you know that many humans who read large XML schemas in their spare time you need to get yourself and your friends “to a nunnery”. OK, maybe not but you get the point 😉
- It often seems that around 20 years of distributed systems thinking was ignored in their creation. Hence SOAP was misnamed “Simple”. “Incomplete” would have been more appropriate.
- With usefulness comes complexity. With complexity comes unwieldiness and with unwieldiness comes confusion. The secret is normally appropriate abstraction but it’s early days yet
- The standardisation effort is frustrating and feels uncoordinated. All too often standards are hurriedly created to plug holes in other standards. Often if feels like the wheel is being reinvented, as if nobody in the effort knows that RPC has been done before. I hear Vinoski’s cries for an overarching Architecture spec so have both a map and a flashlight
- Almost none of this matters as the major industry players are now behind it in a bid to recapture the goldrush of the late 90s with a ‘must-have’technology. For this reasons alone the tool support will hide much of the complexity and encourage utilisation. This is already happening. Thank you Microsoft, IBM, HP, BEA, IONA, SUN etc.
- The most loosely coupled thing about WS/SOA is often the standardisation process. There could be trouble ahead
However there’s hope for us all in the form of REST. It may correct several issues with webservices (including the loengthy standardisation process). WS piping is so incredibly powerful that it can’t be overlooked. Also, REST provides some neat answers to security issues, automation, semantic web & may just bring about world peace given an appropriate level of vendor support
Arguably the URI is the reason the web took off in the 1st place. There were better transport and application layer protocols, more elegant markup grammars but the idea of the URI is compelling. Arguably with REST, semantic web & canonical URI’s we may just be getting somewhere. I believe that these technologies will determine the success or failure of the web service initiative and everything else is pretty much window dressing.