Almost all allowed relationIRI's (URL's) that can be used in sys_md_Tag result in a 404 error

[dtroelofsprins]

How to Reproduce

Try the molgenis.org URL's as defined in https://github.com/molgenis/molgenis/blob/4b873617cd9ff72be91acfe2bb66047c465e7904/molgenis-data/src/main/java/org/molgenis/data/semantic/Relation.java

Expected behavior

All URL's should work.

Observed behavior

404 Not Found for all URL's except: http://molgenis.org#isAssociatedWith.

=> related to this in Trac the ticket #8290 is created (being able to use other relationIRI's than the allowed ones).

[fdlk]

The relation class contains IRIs, not URLs. URLs are special subset of IRIs, which makes things a bit confusing.

See https://fusion.cs.uni-jena.de/fusion/blog/2016/11/18/iri-uri-url-urn-and-their-differences/ for an explanation of the difference.
But in short: the http://molgenis.org prefix is used here to pick identifiers that are in "our" namespace.