Require Google to return email address as part of OAuth

Question

I am using OAuth to access Gmail with dotNetOAuth. How can I force Google to return user's email address as part of callback after authorization?

By default, Google OAuth callback only returns the token secret and access tokens.

Answer 1

OAuth doesn't provide a facility for extra parameters during an OAuth handshake, so I don't think you can force Google to supply it. There is likely a Google API however that you can use your OAuth access token to call to fetch the email address after the handshake, however.