I would like to pass a refresh token to my server to store and use for offline access. I am currently using an iframe into the server and, in Apex, getting the session_id and passing it to the server. Is there any way to get a refresh token or the equivalent access token for offline access?
The Auth.AuthToken class seems to only get the access token and now has the ability to refresh it, but does not have direct access to the refresh token, yes?
Is there some other access credential I have the ability to get inside of Apex?