long1eu / google_sign_in_dart

google_sign_in_dartio

A Flutter package that implements Google Sign In in pure Dart. This package is compatible with google_sign_in plugin and works on all platforms Flutter supports but it's intended to be mainly used on Desktop.

Getting Started

Install and initialization

1. Depend on it

   dependencies:
     google_sign_in: ^4.1.4
     google_sign_in_dartio: ^0.0.6

2. Run flutter pub get
3. Import

   import 'package:google_sign_in/google_sign_in.dart';
   import 'package:google_sign_in_dartio/google_sign_in_dartio.dart';

4. Register the package

   import 'package:flutter/material.dart';
   import 'package:google_sign_in/google_sign_in.dart';
   import 'package:google_sign_in_dartio/google_sign_in_dartio.dart';
   
   void main() {
     if (isDesktop) {
       GoogleSignInDart.register(clientId: <clientId>);
     }
   
     runApp(MyApp());
   }

   Note: You might want to await for the register method to finish before calling any GoogleSignIn methods when your app starts.

Usage

You can use the normal GoogleSignIn methods.

final GoogleSignInAccount account = await GoogleSignIn().signIn();

Obtain a Client ID for your Desktop app

1. Go to the Google Cloud Platform console and select you project
2. Go to APIs & Service -> Credentials
3. Create new credentials for your app by selecting CREATE CREDENTIALS and then OAuth client ID
4. Select Other as Application type, give it a name (eg. macOS) and then click Create

Provide a code exchange endpoint

The user accessToken expires after about one hour, after witch you need to ask the user to login again. If you want to keep the user logged in, you need to deploy a oAuth code exchange endpoint. Once you have your endpoint you can register the package like this.

NOTE:

If you use this only for FirebaseAuth you don't need the code exchange since the token must be valid only when you use the signInWithCredentials method.

    import 'package:flutter/material.dart';
    import 'package:google_sign_in/google_sign_in.dart';
    import 'package:google_sign_in_dartio/google_sign_in_dartio.dart';
    
    void main() {
      if (isDesktop) {
        GoogleSignInDart.register(
            clientId: <clientId>, 
            exchangeEndpoint: <endpoint>,
        );
      }
    
      runApp(MyApp());
    }

NOTE:

GoogleSignInTokenData exposes serverAuthCode field that should contain the exchange code from the authorization request. This will always be null when using this package because we already allow you to provide a code exchange endpoint witch exposes the code and code verifier in a trusted environment and encourages not to do the code exchange on the client.

See instruction on how to deploy a code exchange endpoint.