WADL REST API description language getting some attention
Not everyone is convinced that we need to describe and define REST-ful APIs, but there are those who believe it's useful. Tim Bray suggests that it's what we need to allow users to consume an XML/HTTP API in a few lines of code. It's certainly true that machine-readable descriptions of web APIs can allow the generation of a language-specific library.
For those who would like to describe their XML over HTTP service, a lot of options have been discussed, from SMEX-D (proposed by Tim Bray) to NSDL, and a host of alternatives. However, most of those proposals were made in 2005 or earlier, and since then none has really seen much adoption.
Marc Hadley (one of the Spec Leads for JSR-311, a Java API for RESTful services) back in 2005 proposed WADL, the Web Application Description Language.
Since then, a number of people have been building tools to support WADL. Yahoo architect Mark Nottingham is maintaining a stylesheet to generate documentation from WADL.
Last week, Google's Thomas Steiner unveiled that he is working on a Google project for generating language specific client libraries from WADL and generating WADL from documentation examples, tentatively called Google REST Compile and Google REST Describe. Thomas chose WADL as the description language to be used with the new tool, after examining all the alternatives
The Sun Developer Web Pack was also released last week and contains prebuilt binaries of some WADL tools developed by Marc Hadley.
With architects at Yahoo, Google, and Sun choosing WADL for their REST tooling, perhaps WADL will receive more adoption. For more information on WADL, the reasons behind it and the alternatives, Marc Hadly's presentation (PDF, Google's HTML translation) is a good overview.
I would stay with WSDL
Re: WADL usage and associated benefits
I had done some research, and found some graduate research ils.unc.edu/MSpapers/2830.pdf done by Michael Graves at the University of North Carolina. He did a good job of defining the data schema, etc. But was recommending using RDF/XML. He recommended an ontology called OWL to define the event. I was fine with the data, sources, etc. but kind of got confused at the OWL layer.
I do want the concert and event data to be available and accessible to outside applications, so it looks like WADL will provide a much simpler way to make sure that the data is structured properly. I read through the Sun power point presentation and it seems pretty straightforward. If it continues to be supported by Google, Sun, et all, it should be a pretty safe choice.
implemention of WADL
implemention of WADL
WADL to describe interaction, not services.
Following this, WSDL is not replaced by WADL, but may be complemented by it. A WSDL may define the service, and a WADL generated from it to actually describe a REST implementation of the web service.