Any API to create event on user's calendar without authentication?

[sugiggs]

I need to write a program to insert events/appointments to users' calendar.

I saw an API to import *.ics but it requires user's credentials. Anyway to do it as an admin?

[tdesorbaix]

The ICS files are imported with REST, no?
the admin credentials should work to import with REST in another account.
Here is some informations on it on zimbra blog :
zcs-to-zcs migrations