I'm writing a service that needs an up-to-date information on a user's calendar. However, I have yet to find a way other than regular polling to receive updates from GCal. Is it possible to set up some kind of push notification or an event list diff transmission?
+1
A:
(Disclaimer: I work for Google, and I worked on Google Mobile Sync, specifically calendar sync, but in this answer and everything else I write on this site, I am writing as an individual and not representing Google.)
I don't believe there's a public notification API, I'm afraid. As far as I'm aware, you will need to poll. However, you can of course ask for changes since a particular timestamp; it's not like you have to download the whole calendar every time.
On a secondary note: good luck! I certainly didn't appreciate just how complicated calendaring was until I started working on it...
Jon Skeet
2010-09-18 07:05:07