>On 7-Oct-2009, at 03:02, <[email protected]> wrote: >> I have been going through pubsub and noticed that it is really hard >> (impossible?) to extend it without editing the original schema. I am >> not XSD expert but as far as I know there is no way, for example, to >> add one attribute from own namespace to the schema with >tools provided >> by XSD. The problem is that Pubsub schema defines all elements >> directly as named element and XSD allows extension or >restriction only >> to named complex- or simple types. > > I believe this is on purpose. If you need to add your >own attributes and elements then you should put it in the item >payload with whatever custom xmlns you need. >
Item payload is not always the right place to extend the protocol because in some cases the extension should not be visible to the recipients. Specifying schema in unextendable way leads into a situation where it is possible to extend the protocol but impossible to document the extension in formal way. Cheers, Petri Liimatta
