Ok, so I'm the author of a CMS and I'm interested in building a CalDAV-server that enables the user to interface with my CMS through CalDAV instead of only through the web, so they can see their calendars, add todos and things like that.
I've looked at http://www.davical.org/ which is a CalDAV service built in PHP, but it has its own database and I already have the DB stuff done and just want a middle-layer services that translates, both ways, to and from my databases using my functions.
Any ideas?
SabreDAV http://sabre.io/dav/caldav/ can be of some help.