Need advice on a web service "request template" pattern

We are designing a system which needs to allow the construction of objects made up of data, sourced from disparate datasources (databases, and back office systems for example) and are looking at ways to facilitate this functionality across a web service interface.

To service this requirement we propose creating a "request" object as an input parameter for the web service request methods so the web service knows which fields on the object to populate from which source, a sort of "pick n mix" to poulate your return object.

How could this "Request template" object be designed and is it a suitable approach?

We need the solution to achieve the following:

• Must be clea开发者_如何学运维r to the consumer of the service what the method expects and what will be returned.

• The Consumer must have visibility as to what locations are available for

  each field when constructing the

  request.

• A clear relationship between the response object and the request object exists.

Have you considered using WCF and have the request object use an interface, that way it is extensible as well?