I've situation where I'm looking for single sign on across the apps. I've three appspot URLs say x.appspot.com, y.appspot.com & z.appspot.com in all of which User Profile system is Same. Also we use same kind of admin panel to permit the users on App inside each URL. However now the problem is all the users are scattered across the URLs and we need all of them to be maintained through one centralized app on which if we set permission they shall be able to access the URL permitted.
I'm seeing if single-sign on feature can help us.
You could make an authorization server (like customauth.appspot.com) and query it with
fetchUrl
from x, y, and z. If you make it adhere to oauth protocols then all of Google's oauth stuff should work!