Investigate support for "claims" request parameter in OIDC

[NicolasLiampotis]

Investigate support for requesting Claims using the "claims" request parameter as per https://openid.net/specs/openid-connect-core-1_0.html#ClaimsParameter

[NicolasLiampotis]

@cgeorgilakis We can test support for the Claims request parameter with a demo OIDC client that makes the following Claims request:

{
   "userinfo":
    {
     "given_name": {"essential": true},
     "email": {"essential": true},
     "email_verified": {"essential": true},
     "http://example.info/claims/groups": null
    },
   "id_token":
    {
     "auth_time": {"essential": true}
    }
  }

[cgeorgilakis]

Claims parameter Token mapper exists for OIDC Client. You can only configure boolean Add to ID token and Add to userinfo.

As I understand 'name', 'given_name', 'family_name', 'preferred_username' and 'email' mapping are returned only if essential attribute has value equals to true for "userinfo" or "id_token".

[cgeorgilakis]

PR for this mapper : https://github.com/keycloak/keycloak/pull/7232 ( see comments)

[cgeorgilakis]

PR has been accepted. Is this ok for us?