I've been studying the Google authentication API (AuthSub)... My question is, how do I get the user's account information (at least their Gmail address) after the authentication has passed?
Because currently, all I get back from the authentication process is a token granting me access to which ever Google service I have specified in the scope, but there's no easy way to even get the user's login id (Gmail address) as far as I can tell...
If so, what Google service allows me to access the user's information?
Using the Google AppEngine GData services, you can request the user to give you access to their Google Mail, Calendar, Picasa, etc. Check it out here.