Using strings with "general purpose" XML in WS - good or bad?

Question

We're working now on the design of a new API for our product, which will be exposed via web services. We have a dispute whether we should use strict parameters with well defined types (my opinion) or strings that will contain XML in whatever structure needed. It is quite obvious that ideally using a strict signature is safer, and it will allow our users to use tools like wsdl2java. OTOH, our product is developing rapidly, and if the parameters of a service will have to be changed, using XML (passed as a string or anyType - not complex type, which is well defined type) will not require the change of the interface.

So, what I'm asking for is basically rule of thumb recommendations - would you prefer using strict types or flexible XML? Have you had any significant problems using either way?

Thanks, Eran

Answer 1

I prefer using strict types. That gives you access to client tools that make that end of the job much easier. You also state that if the messaging changes, the string approach will not require changing the interface. Personally, I see this as a disadvantage, not an advantage. If the interface changes, you will know very quickly which clients need to be updated.

Answer 2

Strings containing XML is an extremely bad idea and asking for trouble. Use messages that have a defined schema.I had to rewrite significant portions of an app that used a lot of XML internally instead of types. It was horribly slow and impossible to figure out what was happening.