OAuth-JWT Authentication Service

A Node.js authentication service that implements Google OAuth 2.0 with JWT token generation and verification. This service provides secure authentication using Google's OAuth flow and issues JWT tokens for subsequent API requests.

Features

• 🔐 Google OAuth 2.0 authentication
• 🎫 JWT token generation and verification
• 🛡️ Secure token-based authentication
• 🚀 Express.js REST API
• 📱 CORS enabled for cross-origin requests
• ⚡ Passport.js integration for OAuth strategies

Tech Stack

• Node.js - Runtime environment
• Express.js - Web framework
• Passport.js - Authentication middleware
• Google OAuth 2.0 - OAuth strategy
• JWT (jsonwebtoken) - Token generation and verification
• CORS - Cross-origin resource sharing
• dotenv - Environment variable management

Prerequisites

Before running this project, make sure you have:

• Node.js (v14 or higher)
• npm or yarn package manager
• Google Cloud Console account for OAuth credentials

Installation

1. Clone the repository:

git clone <repository-url>
cd Oauth-JWT

2. Install dependencies:

npm install

3. Create a .env file in the root directory and add the following environment variables:

PORT=5000
GOOGLE_CLIENT_ID=your_google_client_id
GOOGLE_CLIENT_SECRET=your_google_client_secret
GOOGLE_CALLBACK_URL=http://localhost:5000/auth/google/callback
JWT_SECRET=your_jwt_secret_key

Google OAuth Setup

1. Go to Google Cloud Console
2. Create a new project or select an existing one
3. Enable the Google+ API
4. Go to "Credentials" and create OAuth 2.0 Client IDs
5. Add authorized redirect URIs:
   • For development: http://localhost:5000/auth/google/callback
   • For production: https://yourdomain.com/auth/google/callback
6. Copy the Client ID and Client Secret to your .env file

Usage

Starting the Server

For development:

npm run dev

For production:

npm start

The server will start on http://localhost:5000 (or the port specified in your .env file).

API Endpoints

1. Health Check

GET /

Returns a simple message confirming the service is running.

2. Google OAuth Login

GET /auth/google

Initiates the Google OAuth flow. Users will be redirected to Google's consent screen.

3. OAuth Callback

GET /auth/google/callback

Handles the OAuth callback from Google. Returns a JWT token and user information upon successful authentication.

Response:

{
  "success": true,
  "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
  "user": {
    "id": "google_user_id",
    "name": "User Name",
    "email": "[email protected]",
    "picture": "https://profile-picture-url"
  }
}

4. Token Verification

GET /auth/verify
Authorization: Bearer <jwt_token>

Verifies a JWT token and returns the decoded user information.

Response:

{
  "success": "true",
  "user": {
    "id": "google_user_id",
    "name": "User Name",
    "email": "[email protected]",
    "picture": "https://profile-picture-url"
  }
}

Project Structure

Oauth-JWT/
├── controllers/
│   └── authController.js      # Authentication logic
├── routes/
│   └── authRoutes.js          # API routes
├── utils/
│   ├── jwtUtils.js           # JWT token utilities
│   └── passportSetup.js      # Passport configuration
├── index.js                  # Main application file
├── package.json              # Dependencies and scripts
└── readme.md                 # Project documentation

Environment Variables

Variable	Description	Required
PORT	Server port number	No (default: 5000)
GOOGLE_CLIENT_ID	Google OAuth Client ID	Yes
GOOGLE_CLIENT_SECRET	Google OAuth Client Secret	Yes
GOOGLE_CALLBACK_URL	OAuth callback URL	Yes
JWT_SECRET	Secret key for JWT signing	Yes

Security Considerations

• Keep your JWT secret secure and use a strong, random string
• Use HTTPS in production
• Implement proper CORS policies for production
• Consider implementing token refresh mechanisms for long-lived sessions
• Validate and sanitize all user inputs

Error Handling

The service includes basic error handling for:

• Missing or invalid JWT tokens
• OAuth authentication failures
• Invalid token verification

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.