[cddlm] Doubt about "Resolve" operation on System

[Steve Loughran]

Ayla Debora Dantas de Souza - Projeto Ourgrid wrote:
> Hello all,
> 
> we are implementing the "Resolve" operation from the System and we had 
> the following doubts:
> 1. What should happen if in the "path" we specify a prefix, but in the 
> CDL being queried that prefix is not defined?
> As far as we know, XPath does not support queries using namespaces, only 
> prefixes. Considering this, the prefix used must be defined on the XML 
> being queried. Are we right?
> 

That is an interesting thought. you may have found a bug there.

XPath always needs a context to resolve against; it takes the default of 
a node, or you can pass in your own context of prefix,namespace pairs.

I guess we'd assumed that you could just rely on the context of whatever 
descriptor you deployed, but xpath is a lot less brittle in code if you 
provide your own context, as then you are not so dependent upon prefix 
names, which are, after all, just conventions.

Maybe we need to extend the deploy+cmp apis to pass in a context for 
resolution.

> 2. What must happen when the "path" passed for the "Resolve" does not 
> present a prefix?
> We think that in this case, a response representing an emply result 
> should be returned to the user. Ok?

i'd probably envisaged an error, but we need to work with the component 
model design there.

> 
> Thanks,
> 
> Ourgrid team.
>