Hi
The CardDAV support is being implemented as a new and independent plugin as the Kolab addressbook is completely different and does not support backend 'drivers'.
Our CalDAV implementation is using the SabreDAV (http://code.google.com/p/sabredav/) and the sabre-vobject (https://github.com/evert/sabre-vobject) Libraries.
In both cases our target CalDAV/CardDAV server is SOGo
This sounds very cool. Kolab seems like the best implemented PHP calendar/contacts/Notes frontend right now.
However, SOGo already has an excellent web interface which does almost everything Kolab does - I'm slightly curious as to why you don't use it?!
My interest is that I find roundcube slightly more responsive and also simpler to deploy. It's also easier to modify and extend. However, whilst I'm a bit scared by a lot of the code, OwnCloud is looking like my best partner and it's basically a wrapper around sabredav. (I like the DAV filesharing piece for our solution)
As such my initial thought for integration with roundcube was to talk directly to the backend databases. Kolab expects all the fields to be in separate columns, but owncloud simple stores the original vcard/ical field as a blob and it requires parsing. Interested in the design you have gone for - my (naive) thoughts were just to add an ical/vcard parser and connect the DB tables directly - this does require some duplication of business logic though
What is your basic design? Are you connecting directly to DAV? With a local cache? Or directly talking to the backend db structure?
Thanks
Ed W