How eBay Uses Metadata to Enhance Its Web Services
Alan Lewis has a great article up on XML.com on embedding meta-data inside WSDL files.
Since we rev our Web services API every two weeks, we run into versioning problems that aren’t well covered by existing practices. For example, we define a whole set of complexTypes, but those types can morph overtime and we want to maintain backwards compatibility whenever possible. Or, a piece of data may be mandatory in one call, but optional in another.
Seeking a standards-based solution, our documentation team turned to the appInfo element defined as part of XML Schema. It’s quite a nice idea, and also allows us to auto-generate reference documentation from the WSDL file itself. We’d love for other companies who encounter a similar problem to take a similar approach, so that we can pool resources.
If you’re interested, check out Alan’s piece.