Is it possible to use additional providers for firebase authentication?

问题

Apart from the existing providers, is it possible to use an additional provider for firebase authentication? I am using Flutter. Any detail explanation will be highly appreciated.

回答1:

You can indeed create a custom provider for Firebase Authentication. The process on Flutter is mostly the same as on other platforms:

1. You sign the user in the custom backend or provider, and get credentials from that. This step is not related to Firebase in any way.
2. You pass the credentials to a custom trusted endpoint that you create and host, on a server that you control, or on Cloud Functions.
3. In this custom backend, you check the credentials, and then use the Firebase Admin SDK to mint a custom token for the user.
4. You return this custom token from the backend to the application.
5. The client then uses the custom token to sign in with Firebase.

来源：https://stackoverflow.com/questions/61156964/is-it-possible-to-use-additional-providers-for-firebase-authentication