[Calendarserver-discuss] Free Software calendaring and groupware (in and beyond Debian)

Paul Boddie paul at boddie.org.uk
Fri Nov 6 18:28:35 UTC 2015

On Friday 6. November 2015 17.41.40 Guido Günther wrote:
> Hi Paul,
> On Fri, Oct 23, 2015 at 06:27:17PM +0200, Paul Boddie wrote:
> > 
> > What I'm missing, though, is the path that people might take if they're
> > already using an MTA and other things. All of these "all in one
> > solutions" make choices on your behalf, which is probably great for the
> > person building their own little groupware empire from scratch, but not
> > so great for people who are already managing infrastructure.
> I fully agree here. It would be nice to have better integration for
> things like calypso/radicale/calendarserver without lots of effort + web
> frontends that can cover these things too. And then there's interacting
> with invitations in your mail stream...

Actually, one thing I never seem to read anything about is how the CalDAV 
solutions use e-mail. I guess they connect to an SMTP server and fire off 
invitations when you manipulate events (and other things), but I've never 
found any documentation that mentions this. Maybe I didn't look hard enough, 

Here's what I wrote up about the matter:


But yes, you have to be able to receive mail and then act on it, and that 
needs awareness in the mail software unless you have the CalDAV server 
integrate with the MTA, which is also something I don't remember reading 
anything about. (At least not with the "lightweight" solutions. Zarafa and 
Kolab both integrate with the MTA and you can find out about this if you dig 
deep enough in the documentation.)


> > I'm aiming to release this very soon. I'm sure it might be described as
> > old- fashioned, but it just operates by adding mail handlers that
> > understand calendar objects and can build scheduling information from
> > sent and received events.
> > 
> > Initially, I thought that all I would be doing was filling in some very
> > small gaps in mail client functionality with regard to calendaring, but
> > as I've been filling out the support for the more exotic parts of the
> > RFCs, I've noticed that various clients don't support certain things at
> > all. For instance, unless it has been added recently, Lightning/Iceowl
> > doesn't support COUNTER messages. And Claws doesn't support recurring
> > events at all, as far as I can tell.
> > 
> > Perhaps a lot of focus has been put on Web-based clients, and perhaps I
> > should look at them a bit closer to see if they implement more of the
> > iTIP specification.
> calendarserver has some support for this but I've not looked at it,
> maybe the maintainer can chime in?

Well, I've started writing up my own solution, and details can be found here:




There are lots of rough edges, I think, but I feel that I understand the 
domain a lot better than I did, and I also feel that this work puts me in a 
better position to support some of the more interesting use cases that never 
seem to get properly addressed, at least in generic, publicly-available Free 


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