Google apps script: OAuth2
I am writing a Google Docs add-on in Google apps script. The add-on takes some data from the page and makes an entry in my web app. The problem is that I need to authenticate the user in my web app, which supports OAuth 2.0 and doesn't support OAuth 1.0
Google is very strict in what add-ons are allowed to do. The only way I found to show the authentication dialog to the user is via UrlFetchApp.addOAuthService(serviceName). But this function only supports OAuth 1.0, as I get it.
So the question is: is there a way to authenticate a Google Docs user in my web app via OAuth 2.0?
There is an issue filed on code.google.com asking for that, back from Nov 2011 and not yet resolved (https://code.google.com/p/google-apps-script-issues/issues/detail?id=929). But I hope a workaoround exists.