[oslc-core] creation factories and read-only properties

[Dave]

On Mon, Jun 20, 2011 at 11:00 AM, Paul McMahan <pmcmahan at us.ibm.com> wrote:
> I don't see any discussion in the core spec about how a service provider
> should respond when an OSLC client includes a read-only property in a
> creation request.
> For example, in the QM spec the dcterms:modified
> property is designated as read-only for all of the QM resources.   If a
> client includes this property in a creation request then I could see a case
> for the service provider simply ignoring it.   But on the other hand I
> could also see a case for the service provider rejecting the request since
> the client might otherwise be unaware that a property in its creation
> request had been ignored.   There is also a similar situation where the
> client includes an unknown property in the creation request.   I would
> appreciate any guidance or feedback that the OSLC core workgroup could
> provide in this area.

In the Core spec, we say:

"For OSLC Defined Resources, clients SHOULD assume that an OSLC
Service will discard unknown property values. An OSLC Service MAY
discard property values that are not part of the resource definition
or Resource Shape known by the server."

I think that gives providers license to quietly ignore properties that
are not recognized, or that are not recognized for a specific use
case.

The dcterms:modified and dcterms:identifier are good examples of this,
both are set by the provider and not expected to be included in a
creation POST request.

In my opinion, it's better to make creation easy, and therefore to
quietly ignore and discard unnecessary or unknown values in a creation
request.

- Dave


-- 
David M. Johnson
OSLC Core Workgroup Lead
IBM Rational Software