Re: How to define context for new (custom) properties of JSON document

Hi Zee,

As bare minimum you would only need to define a URI for the properties/classes you use. Describing those could be done at a later stage.

Regards,

John

On 26 Oct 2014, at 02:07, Zee <fortechie@gmail.com> wrote:

> Thanks Nicholas! This helps and it confirms my understanding of json-ld that I have to have external-vocabulary defined for every property that is not yet modeled by well-known standard (schema.org/foaf.etc.).
> 
> Since the API I'm currently working on is going to be consumed internally (not public), I have decided to keep it simple and use instead 'HAL specification'. I understand that per HAL it requires out-of-band mechanism to communicate context and for that I will rely on our API documentation for now.
> 
> Thanks,
> Zee.
> 
> 
> On Sat, Oct 25, 2014 at 8:22 AM, Nicholas Bollweg <nick.bollweg@gmail.com> wrote:
> Looks like some interesting stuff. Unfortunately, I'm not sure if ontologies can be all three of simple, specific, and standards-compliant, at the same time.
> 
> I created json-ld playground link..
> I didn't know that gists worked as remote docs! That's great!
> 
>  how to define context for properties (keys) that doesn't have a standard ontology
> Congratulations, you probably have to make a new ontology! 
> 
> If you want simple and specific, the easiest way to blanket capture otherwise-unmodeled things is with @vocab, take a look at the spec.
> 
> Adding this to your context:
> "@vocab": "http://myapp.com/",
> and removing all your null pairs, as you can read there, will expand:
> "twitterUserId": "x"
> as
> "http://myapp.com/twitterUserId": {"@value": "x"}
> 
> The issue now is that you have created a new vocabulary, that doesn't map to any other vocabularies. So how about specific and standards-compliant? 
>  
> I lose that the image is gravatarImage not just any image
> Ah, but that is what you said in your context! The above vocab thing will make it into a myapp:gravatarimage. If you really need it to be myapp:gravatarImage and sdo:image, you need to provide an additional mapping from myapp:gravatarImage to sdo:image... 
> "@context": {
> ...
>   "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
>   "gravatarImage": {"@id": "http://myapp.com/gravatarImage", "rdf:subPropertyOf": "sdo:image"}
> ...
> }
> 
> The user of your data would then need to support the RDF class inheritance stuff, which, while powerful, is not really a thing one should have to expect to use JSON-LD.
> 
> Another way, which is simpler, but not as pretty, would just be to include it twice:
> "gravatarImage": <url>,
> "imgage": <url>
> 
> Not sure if this helps, but maybe some look into! 
>