[deepamehta-users] json ld

[Jörg Richter]

Hi,

as I understood it a JSON-LD document is an arbitrary JSON document that is enriched by a "context" which basically maps the property names used in the JSON document to terms of known ontologies. This way a JSON document is connected to the RDF world and thus becomes part of the semantic web. What seems attractive about JSON-LD is its lightweight character that indeed makes it easy to make any JSON exporting application "semantic-savvy".

I would not integrate JSON-LD in the DM core in any way in order to keep the core format agnostic. On the other hand it would make perfect sense to build a "dm4-json-ld" plugin to deal with the JSON-LD features. Its service would basically offer:
	1) emitting a JSON-LD context for any given DM type URI
	2) let other plugins register mappings from their provided types to terms of known ontologies 
	3) optional: exporting arbitrary DM objects to plain JSON

Point 3) means creating plain JSON like ...

	{
		"name": "Malcolm X",
		"died": "1965-02-21"
	}

... instead relying on DM's rather verbose "meta" JSON (as exported by the DM Core service):

	{
		"id": 1234,
		"uri": "...",
		"type_uri": "dm4.contacts.person"
		"value": "...",
		"childs": {
			"dm4.contacts.first_name": {
				"id": 2345,
				"uri": "...",
				"type_uri": "dm4.contacts.first_name",
				"value": "Malcolm X",
				"childs": {}
			},
			"dm4.contacts.date_of_death": {
				"id": 3456,
				"uri": "...",
				"type_uri": "dm4.contacts.date_of_death",
				"value": "1965-02-21",
				"childs": {}
			}
		}
	}

Note: while in the former the properties ("name", "died") originate directly from the application domain, in the latter most of the properties ("id", "uri", "type_uri", "value", "childs") originate from DM's meta-model.

While not knowing enough about it I guess that a JSON-LD context resp. a RDF processor is not able to access the relevant parts from DMs meta JSON. That's why I guess point 3) is required.

Thank you, Jürgen, for pointing me to JSON-LD. Indeed their is a close affinity to DM, and DM could benefit from it. I would appreciate if somebody would be inclined to develop such a plugin, and offer any possible support.

Cheers,
Jörg


On Mar 4, 2015, at 22:18, Juergen Neumann wrote:

> More info here: http://www.w3.org/TR/json-ld
> 
> Am 2. März 2015 19:12:08 MEZ, schrieb Juergen Neumann <j.neumann at junes.eu>:
> Hi Jörg and all,
> 
> last week I had a meeting with two cute software developers. They were pointing me to json ld. They wanted to know if we could improve DM to export json ld enhanced data over the rest api. From what I understand DM is perfectly ready for json ld and it should only take very little effort to improve it in this direction. I thInk this would be of great relevance to make DM more a tool of choice in the growing semantic data scene. 
> 
> Curious about your feedback!
> 
> JuergeN