Retrieve Google Auth tokens from Okta sign-in?

I have an application that relies on access to Google Calendar. And, until now, I have authed through a “Sign in with Google” option, requesting the needed Calendar scopes.

What I’m trying to accomplish: I would like allow Okta customers the ability to authenticate (mostly so I can support the SCIM management). The trouble is I am not clear on how to retrieve the needed Google auth credentials to access the Google Calendar API.

Where I’m at, so far:
In my own Okta instance, I have successfully configured Google as an IDP, and can authenticate (OIDC) into Okta with my Google credentials, from my Node app. However, the external_id, access_token, and refresh_token are all relevant to Okta, not Google.

The Question:
Is there a way to get the needed Google authorization elements, from my handshake with Okta?

You probably want to take a look at this request to get the user’s tokens for their IdP instead of Okta: Identity Providers | Okta Developer

@andrea Thank you for your help. I am able to get both the access_token and an id_token, though I’m not quite clear what I can do with that last token.

The Access Token works great… until it expires. And re-authing into Okta does not retrieve a new token. One needs to go to the Okta portal and sign out, in order to get a fresh token.

So this leaves me with two other bits of info I’m looking to track down:

  1. The IDP’s (Google’s) Refresh Token. Normally, you need to go through Google’s “offline” OAuth2 handshake to retrieve this. But Okta is handling the auth here. Is there a way, that you’re aware of?
  2. The IDP’s UserId/ExternalId. The ID that I’m getting through OIDC does not appear to work (I assume it’s the Okta ID).

Any ideas?

~Andrew

  1. Okta does not request/use a refresh token from the external IdP. We only rely on being able to authenticate the user once to their IdP in order to log them into the Okta org and don’t fetch new tokens for the user’s IdP if/when they expire.
  2. Is it possible this ID is stored within the ID token? The ‘sub’ claim should be a unique ID on the Google side, so it should contain the user’s Google ID.

@andrea Thank you for your response and your help stepping through all of this.

  1. I fully appreciate Okta’s role in the authentication effort, here, and understand why you don’t currently request a refresh token. But if I can’t retrieve a refresh token from the IDP (Google, in this case), then integrating with Okta becomes more of a headache than an opportunity; requiring a second auth consent. Do you have any suggestions on retrieving this, outside of a second, direct-to-Provider OAuth handshake?
  2. Thank you. You were right on the money! I was having trouble with the “validation” step, but the decrypted token_id does have the sub property, which is that external User ID.

~Andrew

Bumping this to see if anyone has any better thoughts on this. :grin: