[oslc-core] Fw: Issue with the Use of dcterms:title and dcterms:description with oslc:ResponseInfo

[Dave]

Thanks for pointing out the error of our ways. I think that we all
forgot paging is optional and must be requested by the client. More
comments below.


On Fri, Nov 26, 2010 at 8:22 PM, Martin Nally <nally at us.ibm.com> wrote:
> Regardless of the answer to the question on 302/303 redirects, I like your
> suggestion that the server should be allowed to return the first page in
> response to a GET on the whole list (contrary to what I originally wrote).
> If we allow this, I would like us to mandate that the server provide a
> content-location header in the response that indicates that the resource
> that was returned is in fact http://example.org/bugs?oslc:pagination=true,
> not http://example.org/bugs. This gives the client two ways to recognize
> what just happened - it can notice that the resource returned is different
> from the one requested, or it can look for a nextPage property in the
> representation. More generally, it provides the client with a specific
> indicator of the "implicit redirect" that happened on the server without
> having to guess based on the representation. When we get our verification
> test suite going, it should check for this.

We required clients to ask for paging via oslc.paging=true because we
had lots of feedback from implementation teams telling us that clients
could not handle paging. We removed it and other features (e.g. in
query syntax) because we were under pressure to simplify the spec.

Even if things have changed and client implementations (we know about)
can all now handle paging, it's pretty late in the spec process to be
making such a fundamental change.

Do we have a handle on the impact to existing implementations and can
we tolerate it?


> Several people have noted that the term "ResponseInfo" does not fit the
> conceptual model currently documented in the spec. I think this term is may
> be a relic a different conceptual model that was previously proposed and
> discarded. Any chance we can change the name to match the model? Page would
> be the obvious choice of term.

Page is a better term, I agree, but we are very late in the game now
so I have the same question as above.


> RDF representations lend themselves very nicely to pagination, because an
> RDF graph has no structure - it's just a set of triples, so is easy to
> break into subsets. Some other representations, like HTML, are much harder
> to paginate, and in fact I find it hard to imagine a satisfactory way to
> paginate HTML (maybe 2 pages - one with the head and one with the body).
> JSON might also be tricky to paginate. Is pagination only expected to work
> with RDF? If so, the spec should say so - I didn't find anything when I
> looked. If pagination is expected to work with other formats like JSON, I
> think the spec needs explain how to paginate them.

The spec does explain how to paginate JSON using oslc:ResponseInfo and
oslc:nextPage.

http://tinyurl.com/3yxuxvz - or -
http://open-services.net/bin/view/Main/OSLCCoreSpecAppendixRepresentations#Guidelines_for_JSON


> It's not clear what totalCount refers to. Is it simply the number of
> triples? The spec says "the number of results", which is a bit vague. I
> think we should clarify.

Yes, this should definitely be clarified. I'll get it on the work-group agenda.

Thanks,
Dave