[CalendarServer-users] Principal URL vs. Alternate URIs vs. Calendar User addresses

[Frank Strauß]

Hi CalDAV experts,

can someone please explain the difference between the UUID-based
principal URL of a principal and his/her alternate URIs and his/her user
address(es)? When I direct my web browser at something like
http://cal.example.com:8008/principals/users/brandt/ I can see something
like

======================================================================
[...]

Principal Information
---------------------
GUID: 5a7b217b-5243-5e35-816b-fe08a47b3f50
Record type: users
Short name: brandt
Full name: Jens Brandt
Principal UID: 5a7b217b-5243-5e35-816b-fe08a47b3f50
Principal URL: /principals/__uids__/5a7b217b-5243-5e35-816b-fe08a47b3f50/

Alternate URIs:
 -> /principals/users/brandt/

[...]

Calendar user addresses:
 -> mailto:brandt at ibr.cs.tu-bs.de
 -> http://cal.ibr.cs.tu-bs.de:8008/principals/users/brandt/
 -> /principals/__uids__/5a7b217b-5243-5e35-816b-fe08a47b3f50/
 -> /principals/users/brandt/
 -> https://cal.ibr.cs.tu-bs.de:8443/principals/users/brandt/
 -> urn:uuid:5a7b217b-5243-5e35-816b-fe08a47b3f50
 ->
https://cal.ibr.cs.tu-bs.de:8443/principals/__uids__/5a7b217b-5243-5e35-816b-fe08a47b3f50/
 ->
http://cal.ibr.cs.tu-bs.de:8008/principals/__uids__/5a7b217b-5243-5e35-816b-fe08a47b3f50/
Collection Listing

[...]
======================================================================

When I use URIs like the "Principal URL" for ACL configuration, it seems
to work as expected. However, it would be nice, if more verbose
addresses like "/principals/users/brandt/" would also work.

I think a mapping from any of the alternate addresses to the UUID could
and should be done before it gets applied to an ACL. What do you think?