Re: LDP Implementation Report for Callimachus

Hi Dave,

Here's some feedback on your feedback.  Great to see such progress
from the Callimachus effort.

On Fri, Oct 3, 2014 at 11:35 AM, David Wood <david@3roundstones.com> wrote:
> Hi all,
>
> Please find attached the LDP [1] implementation report for Callimachus [2], submitted in accordance with the LDP Test Suite [3].  Kudos to James Leigh for his work implementing and testing Callimachus' LDP compliance.
>
Thanks, I have added this to WG conformance report: [1]

> We note that the "LDP Working Group proposes the REMOVAL of indirect containers, unless more implementation reports arrive shortly”.  Please consider this implementation report relevant to that decision.  We request that you RETAIN the concept of indirect containers specifically to allow containers to have flexibility to separate their URIs from URLs used in HTTP request operations.  We believe that retention of indirect containers will facilitate the migration to LDP support by other systems.
>
> Callimachus currently fails three (3) MUST tests:
>  - MemberResource-GetResourceAcceptTurtle
>  - IndirectContainer-GetResourceAcceptTurtle
>  - IndirectContainer-PostJsonLd
>
> We believe that all three of those fail due to an overly-restrictive test suite:
>
> a) 4.3.2.2 "LDP servers should respond with a text/turtle representation of the requested LDP-RS whenever the Accept request header is absent".
>
> This one is problematic for at least two reasons.
>
> First, testing for 4.3.2.2 should not be a MUST requirement (the spec says it is a SHOULD).  At a minimum the test should be downgraded to a SHOULD or split up testing of 4.3.2.1 and 4.3.2.2 into different tests (MUST and SHOULD respectively).

You must have an older version of the test suite, though looking at
James' pull request I think I better understand what the problem is.

> Secondly, the test suite sends an Accept header of "*/*", which is (for most purposes) similar to IE's Accept header of "image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/x-shockwave-flash, application/msword, */*".
>
> Anyone that wants to make their LDPR available to IE is going to have trouble with section 4.3.2.2.  Callimachus responds with a Content-Type of text/html in such cases for purposes of maximizing interoperability.
>
> b) 5.2.3.14 "LDP servers that allow creation of LDP-RSs via POST must allow clients to create new members by enclosing a request entity body with a Content-Type request header whose value is application/ld+json".
>
> Accepting @graph is not required to comply with 5.2.3.14, but the test requires it.  This could have been an overly-ambitious test author.  The specification makes no mention of what to do if a JSON-LD document includes one or more @graph parameters.
>
> Callimachus does not now and is quite unlikely to support in the future the creation of some arbitrarily defined container URI just because someone put an @graph in a JSON-LD document.  We are much more likely to either ignore the @graph entirely or possibly note the @graph as a hint to the name of the graph we actually create.  In other words, we would like to reserve the right to ignore it or treat it as a hint.
>
Some of this we get for free using Jena's current support.  We've put
a work around in place [2].

> We did make some local modifications to the test suite to resolve overly restrictive checks where possible.  For example, allowing parameters to Content-Types, such as 'Content-Type: text/turtle; charset=UTF-8'. James plans to issue a pull request to the test suite's GitHub project on Monday, 6 Oct.  We hope that is helpful for others.
>

Thanks, have reviewed/approved most of these already.  Thanks for the
contributions.

We still have some outstanding Indirect Container tests that have yet
to be implemented [3].

Regards,
Steve Speicher

[1]: https://dvcs.w3.org/hg/ldpwg/raw-file/default/tests/reports/ldp.html
[2]: https://github.com/w3c/ldp-testsuite/issues/197
[3]: http://w3c.github.io/ldp-testsuite/manifest/#needCode

> Regards,
> Dave
> --
> http://about.me/david_wood
>
>
> [1] http://www.w3.org/TR/ldp/
> [2] http://callimachusproject.org/
> [3] https://dvcs.w3.org/hg/ldpwg/raw-file/tip/tests/ldp-testsuite.html#submitting-results
>

Received on Monday, 6 October 2014 17:58:21 UTC