Wednesday, August 02, 2006
Web service gurus will always tell you to write web services "contract first". This means defining the schema for your service types, your messages and wsdl definitions before creating your implementation, which is the exact opposite of what you do when you work with Microsoft's tools. The visual studio way of doing it treats the wsdl as a behind-the-scenes artifact that the developer shouldn't need to worry his little head about. If you're using the Visual Studio tool set end-to-end you don't need to be bothered with wsdl or any of the other nasty angle bracket stuff to do with web services. The problem comes when you need to support interoperability with non dot net applications, then attributing your dot net types to produce the correct wsdl schema can be quite tricky. It would be much nicer if you could write your schemas, message definitions and wsdl first and then generate most of the boiler place asmx code from the wsdl. I was recently introduced, by the software architect where I'm contracting at the moment (hello Shelly), to WSCF (Web Service Contract First) which is a free tool that does just that. It's a free download from thinktecture, they're the consultancy headed by Ingo Rammer the remoting guy. It works as a visual studio plug in, all you have to do is write your xsds that define your types and messages (I use xml spy for doing that) and then you just right click on the message xsd file in the solution explorer, and choose 'Create WSDL Interface Description', a nice wizard pops up where you choose some defauls and then whoosh, there's your wsdl. After you've got the wsdl file you can right click on it and choose 'Generate Web Service Code', again a nice wizard pops and before you know it, you've got all your service types and framework generated in C#. Very nice. Thinktecture have also gone to the effort of writing a really nice walk-through for WSCF that gets you up and running really fast, it only took me a couple of hours to produce my first web service with this method yesterday.
Posted by Mike Hadlow at 8:48 pm