RE: what's the subject?

On Sunday, March 08, 2015 3:50 PM, François-Paul Servant wrote:
> I think that a property that allows to link to the "main subject of
> the returned data" is useful. It corresponds to a very real and
> genuine need for basic linked data handling - one that I encounter in
> my LD stuff. It matters to allow easier implementations of clients in
> charge of displaying the data:
> 
> the user clicked "/bob", and receives a RDF graph, possibly with
> several resources and their description. The problem for the client
> is: how should this graph be displayed ? It is much easier if the
> graph is explicit about what it contains: "This a about /robert"
> (whose type is foaf:Person).

Shouldn't the graph be about the resource that was used to retrieve it? In
other words, doesn't the URL tell you what the main resource is? I do
understand that hash URLs etc. complicate this.


> The client can then display or consume
> the data, just on the basis of the content of the returned data (I
> don't say that there aren't any cases where the client can do better
> if it remembers what the user initially clicked, but in many cases, it
> should be enough to just rely on the returned data)

OK


> Note that the example I gave with redirection is one out of many cases
> where it is difficult to guess the "main subject" of the returned
> data. Another example I have in mind is when you have query params
> that can be added to a "base resource" to customize the amount of data
> that is returned (eg /alice and /alice?includeFriends=true).

Good point.


> Should this property be in hydra?

Hydra is mainly about machine clients. In your opinion, how would such a
property help such a headless client? I do understand the benefits for
rendering data etc. for human consumption but can't really see them for
machine consumption.


> As you note, it is very close to https://schema.org/mainContentOfPage,
> but the domain of this property seems to be a web page.

Schema.org uses domainIncludes which means it is possible to use properties
on other classes without having to worry about invalid inferences being
made.


> I have been
> using foaf:primaryTopic for that purpose (but the domain of it is
> "Document"...)

In case of FOAF it is indeed impossible.


> So, I don't know whether such a property should be in hydra, but I
> think that it could often be useful to people using hydra, and there
> should be, at least, a recommended property for that.

I would like to better understand how it would help clients before
discussing whether it is in scope for Hydra.


--
Markus Lanthaler
@markuslanthaler

Received on Friday, 13 March 2015 17:45:04 UTC