@madusha98/expo-google-signin v0.0.2

@madusha98/expo-google-signin

A Google Sign-In module for Expo applications that uses the new Credential Manager and Google Identity Service for authentication and authorization on Android.

Note: This module currently supports Android only.

Features

• Uses the modern Credential Manager and Google Identity Service APIs
• Supports authentication with Google accounts
• Retrieves server auth code for token exchange with your backend
• Configurable OAuth scopes
• Typescript support

Installation

# Using npm
npm install @madusha98/expo-google-signin

# Using yarn
yarn add @madusha98/expo-google-signin

# Using Expo
npx expo install @madusha98/expo-google-signin

Setup

Android Setup

1. Configure your Google API project:
   • Go to the Google Cloud Console
   • Create a new project or select an existing one
   • Configure the OAuth consent screen with the necessary information
   • Create OAuth 2.0 credentials (Web client ID)
   • Add your SHA-1 signing certificate to your project

Usage

import { signInAsync } from '@madusha98/expo-google-signin';

// Basic sign-in with default scopes (profile and email)
async function signInWithGoogle() {
  try {
    const result = await signInAsync('YOUR_WEB_CLIENT_ID');
    console.log('Sign-in successful:', result);
    
    // Send serverAuthCode to your backend to exchange for tokens
    if (result.serverAuthCode) {
      // Call your backend API to exchange code for tokens
      exchangeCodeForTokens(result.serverAuthCode);
    }
  } catch (error) {
    console.error('Google Sign-In Error:', error);
  }
}

// Sign-in with custom scopes
async function signInWithCustomScopes() {
  try {
    const scopes = [
      'https://www.googleapis.com/auth/userinfo.profile',
      'https://www.googleapis.com/auth/userinfo.email',
      'https://www.googleapis.com/auth/calendar'
    ];
    
    const result = await signInAsync('YOUR_WEB_CLIENT_ID', scopes);
    console.log('Sign-in with custom scopes successful:', result);
  } catch (error) {
    console.error('Google Sign-In Error:', error);
  }
}

API Reference

signInAsync(webClientId: string, scopes?: string[]): Promise

Initiates the Google Sign-In flow.

Parameters:

• webClientId (string): Your OAuth 2.0 web client ID from Google Cloud Console
• scopes (string[] | optional): Array of OAuth scopes to request. If not provided, defaults to profile and email scopes.

Returns:

A Promise that resolves to a SignInResult object:

interface SignInResult {
  idToken?: string;         // The ID token from Google (if available)
  displayName?: string;     // User's display name
  familyName?: string;      // User's family name
  givenName?: string;       // User's given name
  profilePictureUri?: string; // URL to user's profile picture
  phoneNumber?: string;     // User's phone number (if available)
  serverAuthCode?: string;  // Auth code to exchange for access/refresh tokens
}

Commonly Used Scopes

• https://www.googleapis.com/auth/userinfo.profile: User's basic profile information
• https://www.googleapis.com/auth/userinfo.email: User's email address
• https://www.googleapis.com/auth/calendar: Access to user's calendar
• https://www.googleapis.com/auth/drive: Access to user's Google Drive
• https://www.googleapis.com/auth/youtube: Access to user's YouTube account

Token Exchange Flow

The serverAuthCode returned by this module should be sent to your backend server. Your server can then exchange it for access and refresh tokens using the OAuth 2.0 token endpoint:

POST https://oauth2.googleapis.com/token

Request parameters:

• code: The serverAuthCode received from the sign-in process
• client_id: Your web client ID
• client_secret: Your client secret (keep this secure on your server)
• redirect_uri: Your redirect URI
• grant_type: "authorization_code"

Troubleshooting

• Sign-in fails with "No current activity": Ensure you're calling the sign-in method when an activity is available.
• No accounts available: Make sure the user has a Google account set up on their device.
• Authorization failed: Check that your client ID is correct and that you've properly set up your OAuth consent screen.

License

MIT