Is there a way to authenticate both Gmail Oauth and Google Contacts API AuthSub at one time?

Question

I can access a users gmail account using oauth, and i can access a users contacts and their contact groups through google contacts API (which uses AuthSub). For my application i need both of these, is there a way i can authenticate both at once, so that i don't require users to go through two separate authentication sessions?

Or is there a way i can get access to a user's contact groups using the Gmail oAuth alone?

Answer 1

I dont think its possible because it seems like authsub is a different process and would need to be handled separately. However, i recommend getting both authenticated at once using oauth by specifying the "scope" parameter of the request to include both the contacts url and the gmail one.