Google OAuth FastAPI Setup

Project Structure

relai/
├── main.py                 # Main FastAPI application
├── auth/                   # Authentication module
│   ├── __init__.py
│   ├── models.py          # Pydantic models for auth
│   ├── jwt_handler.py     # JWT token handling
│   ├── google_oauth.py    # Google OAuth integration
│   └── routes.py          # Auth API routes
├── .env.example           # Environment variables template
├── requirements.txt       # Python dependencies
└── README.md             # This file

Prerequisites

1. Create a Google Cloud Project and enable the Google+ API
2. Create OAuth 2.0 credentials (Client ID and Client Secret)
3. Set up authorized redirect URIs

Setup Instructions

1. Copy the example environment file:

   cp .env.example .env

2. Edit .env and fill in your Google OAuth credentials:

   • GOOGLE_CLIENT_ID: Your Google OAuth Client ID
   • GOOGLE_CLIENT_SECRET: Your Google OAuth Client Secret
   • JWT_SECRET_KEY: A secure random string for JWT signing
   • FRONTEND_URL: Your frontend application URL

3. Install dependencies:

   pip install -r requirements.txt

4. Run the application:

   python main.py

API Endpoints

Authentication Flow

1. GET /auth/google/url - Get Google OAuth authorization URL
2. POST /auth/google/token - Exchange OAuth code for JWT token
3. GET /auth/me - Get current user information (requires JWT token)
4. GET /protected - Example protected route (requires JWT token)

Usage Example

1. Get the Google OAuth URL:

   curl http://localhost:8000/auth/google/url

2. Redirect user to the returned auth_url

3. After user authorization, Google redirects back with a code parameter

4. Exchange the code for a token:

   curl -X POST http://localhost:8000/auth/google/token \
     -H "Content-Type: application/json" \
     -d '{"code": "YOUR_CODE", "redirect_uri": "YOUR_REDIRECT_URI"}'

5. Use the returned JWT token in Authorization header:

   curl http://localhost:8000/auth/me \
     -H "Authorization: Bearer YOUR_JWT_TOKEN"

Google Cloud Console Setup

1. Go to the Google Cloud Console
2. Create a new project or select an existing one
3. Enable the Google+ API or Google Identity API
4. Go to "Credentials" and create OAuth 2.0 Client IDs
5. Add your redirect URIs (e.g., http://localhost:3000/auth/callback for development)
6. Copy the Client ID and Client Secret to your .env file

Security Notes

• Use HTTPS in production
• Configure CORS properly for your domain
• Keep your JWT secret key secure
• Set appropriate token expiration times
• Validate redirect URIs properly