Draft for Kolab 3.0 Free/Busy Service

Hello folks

While the Kolab 3.0 server has a totally revamped Free/Busy information
generator [1] using a cronjob using the libkolab libraries to read the new
Kolab format, making this information available to the clients isn't yet
solved perfectly. We currently have a very simple HTTP service which
delivers the pre-generated files but only if requested username/email
matches a local file name.

Since most users have multiple email addresses and can also be identified
by their username or UID, this delivery mechanism often fails. And an
additional feature request, which popped up in the past, is the ability to
provide Free/Busy information for users not managed by the Kolab groupware
itself. Thus, a perfect service should be configured with additional
external resources that provide Free/Busy information of other users. The
benefit of such a feature is mainly to have a single API endpoint for
clients to treieve Free/Busy data. But in addition to that, even some
format conversion coould be implemented, i.e. to make MS Exchange F/B data
available to clients that only understand the VCalendar format.

In order to generally improve the Free/Busy service of Kolab, I tried to
draft a functional overview of the public Free/Busy API for Kolab 3.0 in
[2] to meet the above mentioned goals.

The concrete implementation is still to be done so feel free to comment
about the proposed functionality and concepts. Now it's the time.

Best,
Thomas

[1] http://wiki.kolab.org/Free_Busy
[2] http://wiki.kolab.org/User:Bruederli/Draft:Free-Busy_Information_Delivery