W3C home > Mailing lists > Public > public-linked-json@w3.org > March 2016

Re: Combining JSON-LD and JSON reference

From: Mitar <mmitar@gmail.com>
Date: Mon, 21 Mar 2016 05:26:19 -0700
Message-ID: <CAKLmikMOY4vv+Fp5fvyPdEUM+VeyhaLTY46MCJS27w2A+ivzmw@mail.gmail.com>
To: public-linked-json@w3.org
Hi!

At the end, I decided to not use JSON Reference and just do:

{
    "@context": {
        "@base": "http://127.0.0.1:8000/api/v2/node/",
        "@vocab": "http://127.0.0.1:8000/api/v2/node/?format=vocab#"
    },
    "@type": "Node",
    "@id": "000c3d9d-5d7c-492a-8d3b-bb8b922ae35f",
    "config": {
        "core.location": {
            "@context": {
                "@base": "_:config/core.location/",
                "@vocab":
"http://127.0.0.1:8000/api/v2/node/?format=vocab#config/core.location/"
            },
            "@id": "123",
            "@type": "Location",
            "timezone": "Europe/Ljubljana",
            "address": "San Juan, Puerto Rico",
            "city": "Ljubljana",
            "country": "SI",
            "geolocation": {
                "@context": "http://geojson.org/contexts/geojson-base.jsonld",
                "type": "Point",
                "coordinates": [
                    -66.073756,
                    18.378287
                ]
            },
            "altitude": 0.0
        },
        "core.project": {
            "@context": {
                "@base": "_:config/core.project/",
                "@vocab":
"http://127.0.0.1:8000/api/v2/node/?format=vocab#config/core.project/"
            },
            "@id": "444",
            "@type": "Project",
            "project": "http://127.0.0.1:8000/api/v2/project/2"
        }
    }
}


Mitar


On Wed, Mar 16, 2016 at 2:41 AM, Mitar <mmitar@gmail.com> wrote:
> Hi!
>
> I have an issue how to combine JSON-LD and JSON reference in a meaningful way.
>
> For example, if I have internally many-to-many relation of devices,
> which I represent as an array:
>
> {
>   "id": 333,
>   "devices": [
>     {
>       "id": 123,
>       "name": "keyboard"
>     }
>   ,
>     {
>       "id": 567,
>       "name": "mouse"
>     }
>   ],
>   "interfaces": [
>     {
>       "id": 999,
>       "path": "key0",
>       "device": 123
>     },
>     {
>       "id": 897,
>       "path": "mouse0",
>       "device": 567
>     }
>   ]
> }
>
> So IDs come from the rows in the database. And now I would like to
> convert this to something meaningful in JSON-LD, but to keep
> references working. So I tried with this:
>
> {
>   "@id": "http://example.com/mapping/333",
>   "@base": "http://example.com/mapping/333",
>   "@context": "http://example.com/context",
>   "devices": [
>     {
>       "@id": "#/devices/0",
>       "@type": "http://example.com/type/keyboard",
>       "name": "keyboard"
>     }
>   ,
>     {
>       "@id": "#/devices/1",
>       "@type": "http://example.com/type/mouse",
>      "name": "mouse"
>     }
>   ],
>   "interfaces": [
>     {
>       "@id": "#/interfaces/0,
>       "path": "key0",
>       "device": {
>         "$ref": "#/devices/0"
>       }
>     },
>     {
>       "@id": "#/interfaces/1,
>       "path": "mouse0",
>       "device": {
>         "$ref": "#/devices/1"
>       }
>    }
>   ]
> }
>
> So this looks like it has desired properties. Relative @id fields
> nicely combine with @base, and $ref can reference those array elements
> as well. The issue is that getting array index is very hard,
> especially for references which point to documents not part of the
> current query. It would be much better if one could reuse row IDs.
>
> But the issue is that JSON references support only array indexes,
> nothing fancy like matching by @Id.
>
> I was thinking of extending JSON reference with @ syntax, to something like:
>
>
> {
>   "@id": "http://example.com/mapping/333",
>   "@base": "http://example.com/mapping/333",
>   "@context": "http://example.com/context",
>   "devices": [
>     {
>       "@id": "#/devices/@123",
>       "@type": "http://example.com/type/keyboard",
>       "name": "keyboard"
>     }
>   ,
>     {
>       "@id": "#/devices/@567",
>       "@type": "http://example.com/type/mouse",
>      "name": "mouse"
>     }
>   ],
>   "interfaces": [
>     {
>       "@id": "#/interfaces/@999,
>       "path": "key0",
>       "device": {
>         "$ref": "#/devices/@123"
>       }
>     },
>     {
>       "@id": "#/interfaces/@897,
>       "path": "mouse0",
>       "device": {
>         "$ref": "#/devices/@567"
>       }
>    }
>   ]
> }
>
> But it is unclear what exactly would be semantics of @ operator. Like,
> to traverse the augmented JSON reference you traverse JSON object, and
> then you get to @ you have to search for @id with the full reference
> as a value? Strange definition.
>
> So what is a recommended way to address this? To have references,
> which you can as needed dereference to fill with subdocuments.
>
>
> Mitar
>
> --
> http://mitar.tnode.com/
> https://twitter.com/mitar_m



-- 
http://mitar.tnode.com/
https://twitter.com/mitar_m
Received on Monday, 21 March 2016 12:26:50 UTC

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