spotizerr-dev/SSO_IMPLEMENTATION.md

SSO (Single Sign-On) Implementation for Spotizerr

Overview

I have successfully implemented comprehensive SSO backend logic for Google and GitHub authentication in your Spotizerr application. This implementation integrates seamlessly with your existing JWT-based authentication system.

What Was Implemented

1. Dependencies Added

• Added fastapi-sso==0.18.0 to requirements.txt

2. New Files Created

• routes/auth/sso.py - Complete SSO implementation with Google & GitHub support
• routes/auth/sso_example.py - Example client for testing SSO functionality
• SSO_IMPLEMENTATION.md - This documentation file

3. Updated Files

• routes/auth/__init__.py - Extended User model to support SSO fields
• routes/auth/auth.py - Updated authentication status to include SSO info
• routes/auth/middleware.py - Added SSO endpoints to public paths
• AUTH_SETUP.md - Comprehensive SSO setup documentation
• requirements.txt - Added fastapi-sso dependency

4. Extended User Model

The User class now supports:

• sso_provider - Which SSO provider was used (google/github)
• sso_id - Provider-specific user ID
• is_sso_user - Boolean flag for frontend use

Environment Configuration

Create a .env file with the following variables:

# Basic Authentication
ENABLE_AUTH=true
JWT_SECRET=your-super-secret-jwt-key-change-in-production
JWT_EXPIRATION_HOURS=24
DEFAULT_ADMIN_USERNAME=admin
DEFAULT_ADMIN_PASSWORD=your-secure-password

# SSO Configuration
SSO_ENABLED=true
SSO_BASE_REDIRECT_URI=http://localhost:8000/api/auth/sso/callback
FRONTEND_URL=http://localhost:3000

# Google SSO (optional)
GOOGLE_CLIENT_ID=your-google-client-id
GOOGLE_CLIENT_SECRET=your-google-client-secret

# GitHub SSO (optional)
GITHUB_CLIENT_ID=your-github-client-id
GITHUB_CLIENT_SECRET=your-github-client-secret

API Endpoints Added

SSO Status & Information

• GET /api/auth/sso/status - Get SSO configuration and available providers

Google SSO

• GET /api/auth/sso/login/google - Initiate Google OAuth flow
• GET /api/auth/sso/callback/google - Handle Google OAuth callback (automatic)

GitHub SSO

• GET /api/auth/sso/login/github - Initiate GitHub OAuth flow
• GET /api/auth/sso/callback/github - Handle GitHub OAuth callback (automatic)

SSO Management

• POST /api/auth/sso/unlink/{provider} - Unlink SSO provider from user account

Enhanced Authentication Status

• GET /api/auth/status - Now includes SSO status and available providers

OAuth Provider Setup

Google SSO Setup

1. Go to Google Cloud Console
2. Create a new project or select existing one
3. Enable Google+ API
4. Go to "Credentials" → "Create Credentials" → "OAuth 2.0 Client IDs"
5. Configure OAuth consent screen
6. Set authorized redirect URIs:
   • Development: http://localhost:8000/api/auth/sso/callback/google
   • Production: https://yourdomain.com/api/auth/sso/callback/google
7. Copy Client ID and Client Secret to environment variables

GitHub SSO Setup

1. Go to GitHub Settings → Developer settings → OAuth Apps
2. Click "New OAuth App"
3. Fill in application details:
   • Application name: Your app name
   • Homepage URL: Your app URL
   • Authorization callback URL:
     • Development: http://localhost:8000/api/auth/sso/callback/github
     • Production: https://yourdomain.com/api/auth/sso/callback/github
4. Copy Client ID and Client Secret to environment variables

How It Works

SSO Flow

1. User clicks "Login with Google/GitHub" button in frontend
2. Frontend redirects to /api/auth/sso/login/{provider}
3. User is redirected to provider's OAuth consent screen
4. After consent, provider redirects to /api/auth/sso/callback/{provider}
5. Backend validates OAuth code and retrieves user info
6. System creates or updates user account
7. JWT token is generated and set as HTTP-only cookie
8. User is redirected to frontend with authentication complete

User Management

• New SSO Users: Automatically created with user role (first user gets admin)
• Existing Users: SSO provider linked to existing account by email
• Username Generation: Uses email prefix, ensures uniqueness
• Password: SSO users have password_hash: null (cannot use password login)

Testing the Implementation

1. Install Dependencies

pip install fastapi-sso==0.18.0

2. Configure Environment

Set up your .env file with the OAuth credentials from Google/GitHub

3. Start the Application

uvicorn app:app --reload

4. Test SSO Status

curl http://localhost:8000/api/auth/sso/status

5. Test Authentication Flow

1. Visit http://localhost:8000/api/auth/sso/login/google in browser
2. Complete OAuth flow
3. Should redirect to frontend with authentication

6. Programmatic Testing

Run the example script:

python routes/auth/sso_example.py

Security Features

Production Ready

• HTTPS Support: Set allow_insecure_http=False in production
• Secure Cookies: HTTP-only cookies with secure flag
• CORS Configuration: Properly configured for your frontend domain
• Token Validation: Full server-side JWT validation
• Provider Verification: Validates OAuth responses from providers

OAuth Security

• State Parameter: CSRF protection in OAuth flow
• Redirect URI Validation: Strict redirect URI matching
• Token Expiration: Configurable JWT token expiration
• Provider Validation: Ensures tokens come from legitimate providers

Integration Points

Frontend Integration

The authentication status endpoint now returns SSO information:

{
  "auth_enabled": true,
  "sso_enabled": true,
  "sso_providers": ["google", "github"],
  "authenticated": false,
  "user": null,
  "registration_enabled": true
}

User Data Structure

SSO users have additional fields:

{
  "username": "john_doe",
  "email": "john@example.com",
  "role": "user",
  "sso_provider": "google",
  "is_sso_user": true,
  "created_at": "2024-01-15T10:30:00",
  "last_login": "2024-01-15T10:30:00"
}

Error Handling

The implementation includes comprehensive error handling for:

• Missing OAuth credentials
• OAuth flow failures
• Provider-specific errors
• Invalid redirect URIs
• Network timeouts
• Invalid tokens

Backwards Compatibility

• Existing Users: Unaffected, can still use password authentication
• Existing API: All existing endpoints work unchanged
• Configuration: SSO is optional, system works without it
• Database: Extends existing user storage, no migration needed

Next Steps

1. Configure OAuth Apps: Set up Google and GitHub OAuth applications
2. Update Frontend: Add SSO login buttons that redirect to SSO endpoints
3. Test Flow: Test complete authentication flow end-to-end
4. Production Setup: Configure HTTPS and production redirect URIs
5. User Management: Add SSO management to your admin interface

Support

The implementation follows FastAPI best practices and integrates cleanly with your existing authentication system. All SSO functionality is optional and gracefully degrades if not configured.

For issues or questions, check the comprehensive documentation in AUTH_SETUP.md or refer to the example client in routes/auth/sso_example.py.