netzooid

Found this quote from Roy Fielding in 2003 while I was poking around for my talk on scalable, secure, & reliable RESTful services:

Why is there no WSDL for REST? Because HTML is the WSDL for REST, often supplemented by less understandable choreography mechanisms (e.g., javascript). That usually doesn’t sit well with most “real” application designers, but the fact of the matter is that this combination is just as powerful (albeit more ugly) as any other language for informing clients how to interact with services. We could obviously come up with better representation languages (e.g., XML) and better client-side behavior definition languages, but most such efforts were killed by the Java PR machine. Besides, the best services are those for which interaction is an obvious process of getting from the application state you are in to the state where you want to be, and that can be accomplished simply by defining decent data types for the representations.

Sorry Roy, but ugliness matters. If it didn’t matter I probably wouldn’t care about REST. But there is something very nice about a uniform interface, URLs, etc. I will agree that proper resource oriented data types do make a big difference, but the issue to me is how do I even communicate that some datatype is available? If I’m supposed to define my own content types, surely I need a way to communicate what the some of the possibilities are and what they represent? Not everyone is going to understand application/purchase-order+xml off the bat. And surely application/purchase-order+xml might mean different things in different contexts - i.e. different companies or divisions.

I would also argue that HTML is insufficient for this, but thats for Some Other Day when I can actually finish off a larger blog post on the issue :-).

This entry was posted on Thursday, April 26th, 2007 at 11:51 pm and is filed under Random.