http/s and sameAs equivalence, usefor and canonical id logic

[rob-metalinkage]

Two related issues relate to whether it is policy for an installation to assume http and https versions of a URI are equivalent, which is preferred, and explicit owl:sameAs. related is the use of a particular version under a unversioned uri.

sometimes these can be done in the redirect layer - but it may leave the user confused - or not inform them of the canonical form they should use.

proposal is to say assertion of http/https is a data issue - and assertion of a sameAs relationship in the data, with perhaps a subproperty of this to indicate canonical version.

the requirement is for Prez to show all properties of an object and its sameAs asserted equivalents, and highlight the canonical identifier if the user has reached it by a non-canonical identifier path.

[avillar]

One way to support HTTP/HTTPS equivalence (if that is desired) would be to alter the SPARQL queries used to retrieve information about a resource so that they query for both versions of a URI, for example by adding a VALUES ?uri { <httpVersion> <httpsVersion> } clause. Of course, that also means:

1. Having to modify many (all?) SPARQL queries.
2. Introducing a (small?) performance penalty (the datastore has to run effectively two queries).

Once results are retieved, Prez / the UI can check whether results are for the HTTP or HTTPS version, and let the user know the canonical one.