Re: A question on RWPM: why the 'metadata' tag?

> On 9 Jan 2018, at 16:20, Hadrien Gardeur <hadrien.gardeur@feedbooks.com <mailto:hadrien.gardeur@feedbooks.com>> wrote:
> 
> Hello Ivan,
> 
> JSON-LD is always a balancing act between pure JSON documents and the RDF output.

Exactly. Therein lies the problem of JSON-LD, usually...

> 
> For RWPM, the priorities were:
> generic hypermedia format first
> linked data second
I can symphatize with this priority, of course.

> By separating the metadata in a metadata object, we can do the following:
> whenever a client encounters an element that's neither metadata or links, it can assume that it's a collection
> collections are well defined, which means that even if a parser doesn't know anything about the role of the collection, it can be properly parsed and presented to the client
> any foreign element in metadata can be treated as additional metadata as well
> I agree that from an RDF standpoint it would be better to avoid the blank node, but there are clear benefits to this approach as well:
> extensibility
> it's possible to write a generic parser/client that knows nothing about context documents or collection roles
My main problem is not the blank node. I know that many in the LD community are up in arms against it, but I may be less sensitive.

My problem is making owl:sameAs a central aspect of the data; what I expect that, in practice, all the linked data that is hanging on that blank node will be, essentially, useless in (Linked Data) practice, because tools will not reach that data (apart from OWL reasoners and triple stores that know how to reason with OWL terms, which is a small minority of the usage).  My claim is that the current structure produces possibly lots of Linked Data that will become totally useless… then why do it?

A possibility is that _only_ the JSON object in metadata should be considered as RDF metadata, and all the rest is ignored. I am not yet sure how to achieve that with @context  (maybe by using @context only in that object, I have to check with the JSON-LD spec).

Ivan

> Basically, this makes it easier for non JSON-LD aware clients to write code that will handle potential extensions easily.
> 
> We already use this for OPDS 2.0, that introduces additional collection roles and metadata, yet retains the same model.
> 
> Best,
> Hadrien


----
Ivan Herman, W3C
Publishing@W3C Technical Lead
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