We have an Exchange-like mail server at work, but it doesn’t support
iCal subscriptions. Since I use a Mac, and don’t have any interest in
Outlook, that makes calendar access a pain.

After some poking around, I discovered that the server stores the
calendar information in IMAP folders, with each event in a separate ICS
file attached to a fake message. So I put together a small script read
the IMAP messages and merge the ICS files into a single output file. By
writing the output file to a folder on the web server, it is easy to set
up a subscription in iCal.

The result only works one way, of course, though it should be possible
to push fake messages into the IMAP server. I have not tried that,
because I just use the server’s web interface for adding new events to
the calendar.

The script depends on the icalendar package from, and
the Python standard library packages for IMAP and email parsing.

I have posted the script to my server: mailbox2ics.