Re: LDPR Interaction Model on Create

Hi Nandana,

On Mon, Oct 13, 2014 at 9:59 AM, Nandana Mihindukulasooriya
<nmihindu@fi.upm.es> wrote:
> Hi John/SteveS,
>
> On Fri, Oct 10, 2014 at 5:50 PM, John Arwe <johnarwe@us.ibm.com> wrote:
>>
>> Moving this onto the right list for drafting a consensus response.
>>
>> > I also have a small comment that I've been meaning to send regarding the
>> > interaction model.
>> >
>> > 5.2.3.4 states that "Clients use the same syntax, that is HTTP Link
>> > headers, to specify the desired interaction model when creating a
>> > resource as servers use to advertise it on responses."
>> >
>> > I noticed that in the primer, the POST request to an LDP-BC does not
>> > contain a link header expressing the type of the resource to be created.
>> > That also seems to be the behaviour of test suite. However, the POST
>> > request to an LDP-DC *contains* the Link header Link:
>> > <http://www.w3.org/ns/ldp#Resource>; rel="type", while *none* of the
>> > examples in the LDP spec show a Link header being sent with POST
>> > requests.
>>
>> THAT should be fixed, for sure.
>> The only way a LDP client gets predictable behavior is by specifying the
>> interaction model.
>> That's what the examples should show, period... that which is
>> interoperable.
>
>
> I'm a bit confused regarding what is the consensus regarding including the
> interaction model header and what to do in the primer examples on
> POST/Create.
>
> In a previous email SteveS mentioned "I think requiring the header on create
> was not intended and not desirable.  IF the header is present AND the server
> can honor the request, then the client overrides whatever the server would
> have done based on the content.  So I think that it makes complete sense for
> LDP servers to determine the interaction model based on the content of the
> creation request, with the Link header being part of that.". I thought it
> was more biased towards not including the header in the primer examples.

Just stating my personal preference to "point people in the right
direction" instead of "entirely open".  So I'd suggest we put
something in BP (maybe primer) that says when client doesn't supply
Link: rel="type" it is impl-specific, though they could dig into the
content, find rdf:type to determine IM and send back Link: rel="type"
indicate what it picked for the newly minted URI.

> But John's reply as well as Issue-91 suggests that we should include the
> type Link relation header in the POST creation requests.
>
> So shall we include the interaction model header in all the POST creation
> examples?

POST creation of LDPCs, yes.  POST creation of LDPRs, no.  I'm not
sure what including type="LDPR" would mean when posting a LDPR to a
LDPC, as it should not affect the already set interaction model of the
LDPC.  Perhaps that is some extension to indicate on a per-request to
a LDPC but feels a bit like it would violate what we have a MUST
requirements on honoring client's requested interaction model on
creation of the container (and would need to be expanded to other
operations that affect containment and membership, like DELETE).

- Steve

>
> Best Regards,
> Nandana
>
>
>
>

Received on Tuesday, 14 October 2014 15:06:45 UTC