Authenticating "manually" with Google Sign-in to obtain refresh_tokens

[timfee]

I've seen this question scattered about the internet, and wanted to share how I've approached this using this library. I'd love any feedback, and if there's enough interest, I can share a repo (or try my hand at a PR!)

Scenario:

I want to use Firebase Authentication with Google Signin as a provider, and want to be able to store a refresh_token (from grantOfflineAccess()) to do long-lived stuff on behalf of the user when they're not logged in. Unfortunately, with Firebase Auth, such functionality isn't natively supported with the current implementation of the Google Signin provider.

Solution

I'm signing users in via gapi client-side functionality first, and then am using that credential to signInWithCredential. When I want to call grantOfflineAccess to collect a code and store it, I'm able to do so with the help of a server-side function to do the code exchange.

https://github.com/timfee/gapi-firebase