UserId idp may have prefix

[michielbdejong]

The idp field of a UserId should identify the identity provider of the user, but it's unclear from the current documentation of cs3apis whether this should be done with a domain (e.g. 'cernbox.cern.ch') or with an origin (e.g. 'https://cernbox.cern.ch').

Recently, the users.demo.json file in the ocmd example switched from the first to the second format.

In cs3org/cs3apis#159 I proposed to make the second format the prescribed one, but we don't want to make this a breaking change, so reva should start supporting origin-format for userid idp in addition to supporting domain-format as it does currently.

We should to make the provider authorizer interceptor accept both formats, I'll create a PR.

[redblom]

@michielbdejong We want to finalize this (in the context of #3121).
Can you confirm that the proposed format of the idp field, as origin (eg. https://cernbox.cern.ch) is definite ?

[michielbdejong]

In cs3org/cs3apis#159 (comment) @wkloucek proposed a 3rd option, namely a full URL. So the options are:

1. domain, e.g. "cernbox.cern.ch"
2. origin, e.g. "https://cernbox.cern.ch"
3. full URL, e.g. "https://cernbox.cern.ch/some/path"

I'm OK with whatever you prefer!