Re: Open Annotation / Default Context Location?

On Tue, Feb 26, 2013 at 1:52 PM, Markus Lanthaler
<markus.lanthaler@gmx.net> wrote:

>> One issue that has come up is where to maintain the default context.
>> It's not a namespace or ontology, so doesn't quite fit in the
>> w3.org/ns/ space. We don't have a /TR/ as we're a community group like
>> yourselves.  We could use a PURL (purl.org, w3id.org, etc) as the URI,
>> but that just adds hops that processors need to resolve.
>> Is this something that could be addressed in this community group, at
>> least as far as a request to the W3C as to how to proceed?  I imagine
>> that it will be a common occurrence as JSON-LD implementations become
>> more prevalent.
>
> That's a tricky question. I have to say I just had a brief look at the
> specs. My first question would be, can't you host it directly on
> openannotation.org? I would also suggest to include some statements in your
> spec saying that it is RECOMMENDED to host the context locally. I mean..
> it's just a small file to put somewhere on a server. If "instance" documents
> can be hosted, a context can for sure as well.

Our thinking was the following:

1. The context definition shouldn't be simply copied everywhere as
then it wouldn't be cached properly or easily recognizable by clients
without dereferencing it.  If it has a single well known URI, then
clients can simply check for that URI and if present know what they're
looking at.  At that point they can likely process as simple JSON,
rather than RDF.  On the other hand, if the same context is copied
around the place, clients would have to at least inspect it to see if
there were changes, at which point they might as well process as RDF
rather than JSON.

1.5  ... Unless there's a mechanism for asserting the equivalence of
two contexts? One could somehow assert owl:sameAs, but that seems to
be mixing serialization metadata and real triples from the graph and
seems undesirable.

2. If there's to be a single well known URI, then it should be as
permanent and "official" as possible.  The openannotation.org site is
fine for the moment, but of course we hope to transition to a working
group structure towards a Recommendation. At which point having a Tech
Report on the W3C site pointing to a URI somewhere else would seem
very strange, if not suspicious.  As the W3C (thank you Ivan) lets us
publish our namespace documents, we figured that they'd also let us
publish the JSON-LD context file, but they don't have anything in
place for doing that yet.

So, we were hoping that if other projects had the same conundrum,
there would be a greater opportunity to end up with a joint solution,
rather than many different ones.

Thanks Markus :)

Rob

Received on Tuesday, 26 February 2013 21:04:59 UTC