More real world web services ...
In my last entry I mentioned something about using industry standard data type and messages. Also I mentioned the great article “Web Services are not Distributed Objects” http://weblogs.cs.cornell.edu/AllThingsDistributed/archives/000120.html, Yasser Shohoud's book on Interface based web services, and some of his other articles and thought I was on to something regarding the “real world”. I also have read the “At your service“ articles on Industry Standard WSDL http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnservice/html/service02062002.asp At my work, our application makes heavy use of web services. These services are based on VS.NET wizard generated code: you create a service (object?) and add a bunch of methods to it. Seems kind of RPCish?
I am interested in data acquisition stuff and looked at what the process control industry is doing. In particular, OPC (http://opcfoundation.org) I requested and received access to the new XML Data Access spec and retrieved a wsdl document for the xmlda service. Looking at it I was surprised to find that they are also using a remote object rpc style. The soap is document/literal, I'm talking about the way a developer looks at the code. Create a proxy object and call methods on it. One method (Browse) has 16 arguments, some of them are out types. I would have thought that a better way would be to create the a Browse query xml message, a browser query response using xml schemas and go from there. This is the path I was headed down on my “learning“ project anyway.
Any way I guess the real world is still operating differently than I thought or hoped. Unfortunately, I'm not a member of OPC and there is no one here that is interested in going beyond what we have done with web services. I'd love to get into discussions with someone. Need to get out more I guess.