python - Send emails from the user that is logged in in my GAE application -

let's assume have users registered in gae application google accounts use access gmail, calendar, contacts etc. confirm app can send email messages gmail account , when click link, "send notification friends", message goes it's supposed go users' gmail accounts. possible without asking users share login , password application?

from gae mail api docs:

the email address of sender, address. sender address must 1 of following types:

• the address of registered administrator application. can add administrators application using administration console.
• the address of user current request signed in google account. can determine current user's email address users api.
• any valid email receiving address app (such xxx@app-id.appspotmail.com).

so, if logging app using users api, can set sender email address associated user's account:

message.sender = users.get_current_user().email()