RE: [xml-dev] RESTful XML for updates?

["Scott, Christopher" <christopher.scott@fiserv.com>]

Thanks for the responses.  It seems that the consensus is that if a
resource is partially updateable, the updateable parts should be their
own resource.  That seems elegant and RESTful.  Thus we're left with
something like:

<Widget>
  <Id>0FAB7894C</Id>
  <CreatedDate>2009-03-05</CreatedDate>
  <State href="./State">INSPECTED</State>
  <Color href="./Blue">Blue</Color>
  <Whatsists>
    <Whatsist href="./Whatsist/1002"/>
    <Whatsist href="./Whatsist/1002"/>
  </Whatsists>
</Widget>

Even so, that leaves me with two questions:

1. Take, for instance, the State element and the Whatsists.  How would
the client know if you could POST to the "State", but not PUT, and only
GET and PUT "Whatsists"?  The server would return a 405 when something
isn't allowed, but I still feel as though the client should be able to
know this information before making another request.  

I suppose we could add an attribute like
rest:methods-disallowed="PUT,DELETE" on each resource, but I'm not
terribly satisfied with that approach.  Perhaps, some meta-data in a
referenced schema (similar to what was suggested by Rusty)?

2. It would seem that for large partially-updateable resources, this
would increase the amount of HTTP traffic over, say, a single update
document.  Furthermore, if keep-alive isn't used, then there is a
significant connection overhead.  For me, however, this isn't a big deal
because my resources aren't that huge, but this design could impact
scalability.  Some sort of container POST with separated documents, as
postulated in the article linked by Peter could be an OK solution to
this. 

~Chris