W3C home > Mailing lists > Public > public-hydra@w3.org > November 2013

Re: making RDF model visible in spec [was: representing hypermedia controls in RDF]

From: Gregg Kellogg <gregg@greggkellogg.net>
Date: Tue, 26 Nov 2013 08:26:46 -0800
Cc: Markus Lanthaler <markus.lanthaler@gmx.net>, public-hydra@w3.org
Message-Id: <5ECF2D3C-1938-43B8-A27B-76E080ED4E22@greggkellogg.net>
To: Ruben Verborgh <ruben.verborgh@ugent.be>
On Nov 26, 2013, at 8:01 AM, Ruben Verborgh <ruben.verborgh@ugent.be> wrote:

> Hi Markus,
>> There's a playground on both json-ld.org and on my site
>> www.markus-lanthaler.com/jsonld/ which lets you do that.
> Is it available as a standalone npm package?
> Otherwise, I just might do that first, so I have a command-line tool like
>   jsonld file.json

If you install the Ruby "linkeddata" gem, you can transcode using the "rdf" command:

  rdf serialize --output-format turtle input.jsonld # Either a file or a URI.


>>> a) Turtle is still not standardized
>> Neither is JSON-LD :-P
> But JSON has been for a long time!
>>> Counter-question: does Hydra need RDF?
>> It could live without it (now stone me)
> Actually no, that's perfectly fine and has to be considered then.
> What are the arguments for and against RDF for Hydra?
>>> It could be possible to define it just as a JSON subset.
>>> However, the choice was made to use the underlying RDF model;
>>> as such, we cannot pretend it doesn't exist.
>> I don't pretend that.. please don't conflate serialization formats with the
>> abstract data model.
> That's just my point:
> saying that JSON-LD is easier for Web developers is conflating model and serialization.
> When confronting Web devs with JSON-LD, they'll see the JSON model.
> When confronting me with it, that's what I see too (right now, but I should become better at JSON-LD).
> So if you say that JSON-LD is easier for Web devs,
> my answer is that they see the JSON model; but that's only half of the story.
> Hence, do we need the RDF model?
> Which data model does Hydra use: JSON or RDF?
> If the latter, it seems important to make the RDF model visible, perhaps through Turtle.
>> Nope, but it's not the job of the Hydra spec to teach either RDF, nor JSON-LD, nor Turtle.
> No, but it should make visible the model it uses.
> Honestly, I don't care whether it is JSON or RDF;
> I care about the visibility of the underlying model.
>>> So if average Web developers are the core target of the spec, is it
>>> wise to use RDF as model?
>>> (Not being cynical here, honest question.)
>> Puuhh.. how could I possible answer that question? You know that RDF is so
>> general and *in principle* so simple that you can map just about anything to
>> it. That doesn't mean that you have to buy in the whole stack which includes
>> reasoning (which I'm convinced most web devs don't understand)
> Agree on that, Web devs don't understand and don't need to care.
> So important: who of the Hydra users would care,
> and how can we accommodate their needs?
>> and a plethora of newish serialization formats that are just about being
>> standardized (I still find that a bad idea).
> Wow, we said "peace" right? ;-)
>> Let's try and see if the Turtle examples make the spec any clearer.
> Wise!
>> It would also be great if someone could implement a demo similar to the issue tracker
>> demo on my website using Turtle.
> As Turtle, like JSON-LD is just a serialization model of RDF,
> we can just convert the Turtle to JSON-LD and continue from there?
> Instead of a second demo, I just propose to extend the first with content negotiation.
> Ask for JSON? You get JSON-LD.
> Ask for Turtle? You get Turtle.
> Then the client just needs an extra module to convert Turtle to JSON-LD.
> Of course, the client would indicate in its Accept header that it prefers JSON-LD, but takes Turtle too.
>> As you probably know, the spec is on GitHub:
>> https://github.com/HydraCG/Specifications/tree/master/spec/latest/core
>> and uses ReSpec [1]. I think the simplest thing to make some progress here
>> would be a pull request so that we have something concrete to look at. uch
>> appreciated that you spend your time on this!
> You're right. Mind if I postpone this until December? (Have a PhD defense coming up.)
> Cheers,
> Ruben
Received on Tuesday, 26 November 2013 16:27:16 UTC

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