OAuth2 Authentication API

This package provides a simple API for authenticating users using OAuth2 with Google as the provider. It includes endpoints to initiate the authentication process and handle callback responses.

Features

• OAuth2 Integration: Supports Google OAuth2 for user authentication.
• User Information Retrieval: Fetches and returns authenticated user information such as email, name, and profile picture.
• Scalable Design: Implements the Gin web framework for efficient routing and request handling.

Requirements

• Go 1.16+
• Google OAuth2 credentials
• .env file for storing sensitive credentials

Installation

1. Clone the repository:

   git clone <repository-url>
   cd <repository-directory>

2. Install dependencies:

   go mod tidy

3. Create a .env file in the root directory with the following content:

   CLIENT_ID=<your-google-client-id>
   CLIENT_SECRET=<your-google-client-secret>
   

Usage

Local Development

1. Run the application locally:

   go run main.go

2. Open your browser and navigate to http://localhost:8000.

Deployment

For deploying on a cloud provider (e.g., AWS, Google Cloud, etc.), use the provided Handler function as the entry point for handling requests.

Endpoints

1. Root Endpoint (/)

Redirects users to Google's OAuth2 authorization page.

2. Callback Endpoint (/auth/callback)

Handles OAuth2 callback, retrieves the access token, and fetches user information.

Example Workflow

1. Visit the root endpoint (http://localhost:8000) to start the OAuth2 process.
2. Log in with your Google account.
3. Upon successful authentication, the callback endpoint fetches and displays user information as JSON.

Example Response

{
  "id": "1234567890",
  "email": "user@example.com",
  "verified_email": true,
  "name": "John Doe",
  "given_name": "John",
  "family_name": "Doe",
  "picture": "https://example.com/photo.jpg",
  "locale": "en"
}

File Structure

├── main.go         # Main application entry point
├── go.mod          # Module dependencies
├── go.sum          # Dependency checksums
├── .env            # Environment variables
└── README.md       # Documentation

Libraries Used

• Gin: HTTP web framework.
• oauth2: OAuth2 implementation for Go.
• godotenv: Loads environment variables from a .env file.