Web Service to return complex object with optional parts

Question

I'm trying to think of the correct design for a web service. Essentially, this service is going to perform a client search in a number of disparate systems, and return the results.

Now, a client can have various pieces of information attached - e.g. various pieces of contact information, their address(es), personal information. Some of this information may be complex to retrieve from some systems, so if the consumer isn't going to use it, I'd like them to have some way of indicating that to the web service.

One obvious approach would be to have different methods for different combinations of wanted detail - but as the combinations grow, so too do the number of methods. Another approach I've looked at is to add two string array parameters to the method call, where one array is a list of required items (e.g. I require contact information), and the other is optional items (e.g. if you're going to pull in their names anyway, you might as well return that to me).

A third approach would be to add additional methods to retrieve the detail. But that's going to explode the number of round trips if I need all the details for potentially hundreds of clients who make up the result.

To be honest, I'm not sure I like any of the above approaches. So how would you design such a generic client search service?

(Considered CW since there might not be a single "right" answer, but I'll wait and see what sort of answers arrive)

Answer 1

Create a "criteria" object and use that as a parameter. Such an object should have a bunch of properties to indicate the information you want. For example "IncludeAddresses" or "IncludeFullContactInformation".

The consumer is then responsible to set the right properties to true, and all combinations are possible. This will also make the code in the service easier to do. You can simply write if(criteria.IncludeAddresses){response.Addresses = GetAddresses;}

Answer 2

Hi,

Any non-structured or semi-structured data is best handled by XML. You might pass XML data via a string or wrap it up in a class adding some functionality to it. Use XPathNavigator to go through XML. You can also use XMLDocument class although it is not too friendly to use. Anyway, you will need some kind of class to handle XML content of course.

That's why XML was invented - to handle data which structure is not clearly defined.

Regards, Maciej