[cosmo-dev] iCal 3 interop - problem creating calendars

[Brian Moseley]

bug 11216 (<https://bugzilla.osafoundation.org/show_bug.cgi?id=11216>)
describes the problem that occurs when an iCal 3 user tries to create
a calendar on Cosmo. briefly, iCal wants to give everybody on the
server the ability to view free-busy information for the new calendar.
Cosmo doesn't support changing a collection's privileges, and when the
server responds to the ACL operation with a 403 error, iCal breaks so
hard that the iCal account becomes unusable and has to be deleted.

ideally iCal would only try to set this privilege when it's talking to
Apple's server. i will be logging a bug for iCal to suggest this. in
the meantime, we need to come up with some kind of workaround so that
creating calendars with iCal doesn't hose the program.

one option is to pre-emptively give all users on the server the
ability to view free-busy information for every calendar collection.
presumably, then, iCal would notice this when it queries for the
newly-created collection's ACL and wouldn't bother to send the
subsequent ACL request. this seems like a risky policy though. do we
really want any user to be able to do free-busy queries on any other
user's calendars? i'm not sure how sensitively people regard their
free-busy info.

another option is to return a success response for the ACL request but
not actually change any privileges on the server. i don't like this
option because it's effectively lying to the client. we could
potentially do some user-agent detection and only lie to iCal 3.

does anybody have any other ideas?