🛡️ OAuth Server - GitHub & Google Login

A minimal and secure OAuth 2.0 server built with Node.js, Express, and Axios to handle GitHub and Google login flows, cookie-based token management, and profile retrieval.

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🚀 Live Demo

Platform	Frontend	Backend
🔗 GitHub	Frontend	Backend

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📋 Table of Contents

• Features
• Technologies Used
• How OAuth Flow Works
• Run Locally
• Environment Variables
• Test the App
• Folder Structure
• License

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✨ Features

• 🔒 OAuth 2.0 login with GitHub & Google
• 🍪 Secure cookie handling with httpOnly, secure, and SameSite
• 🧠 Token verification middleware
• 📥 Clean API endpoints to fetch user profiles
• 🌍 Deployed on Vercel

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🛠 Technologies Used

• Node.js & Express
• Axios for HTTP requests
• cookie-parser for cookie handling
• dotenv for environment config
• Vercel for deployment

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🔄 How OAuth Flow Works

1. User clicks "Login with GitHub" or "Login with Google" on frontend.
2. Frontend redirects user to backend (/auth/github or /auth/google).
3. Backend redirects user to the GitHub or Google OAuth consent screen.
4. After consent, the provider redirects back to backend with a code.
5. Backend uses that code to request an access_token.
6. access_token is stored in secure httpOnly cookie.
7. Frontend calls /user/profile/github or /user/profile/google to get user info.

🔁 The OAuth flow uses environment variables to dynamically construct the authorization and token exchange URLs.

• GOOGLE_REDIRECT_URI is used in:

  • The initial redirect to Google’s OAuth consent screen
  • The server-side token exchange (/auth/google/callback)

• GITHUB_REDIRECT_URI is recommended for consistency.

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🧑‍💻 Run Locally

Clone the repo:

git clone https://github.com/ajmal92786/oauth-server.git
cd oauth-server
npm install
npm start

Related Frontend Repo

To test the backend via UI, clone the frontend:

git clone https://github.com/ajmal92786/oauth-frontend.git
cd oauth-frontend
npm install
npm run dev

Make sure:

• Backend is running on: http://localhost:4000
• Frontend is running on: http://localhost:3000

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🧾 Environment Variables

📌 .env for oauth-server:

PORT=4000
FRONTEND_URL=http://localhost:3000

# GitHub OAuth
GITHUB_CLIENT_ID=your_github_client_id
GITHUB_CLIENT_SECRET=your_github_client_secret

# Google OAuth
GOOGLE_CLIENT_ID=your_google_client_id
GOOGLE_CLIENT_SECRET=your_google_client_secret

# Redirect URIs
GOOGLE_REDIRECT_URI=http://localhost:4000/auth/google/callback

📌 .env for oauth-frontend:

VITE_SERVER_BASE_URL=http://localhost:4000
VITE_GITHUB_API_BASE_URL=https://api.github.com

📁 Also provide a .env.example for contributors.

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🧪 Test the App

• Visit the frontend: oauth-frontend.vercel.app
• Click “Login with GitHub” or “Login with Google”
• Authorize the app
• Your profile info will be fetched via backend and displayed on the frontend

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📂 Folder Structure

oauth-server/
├── middleware/
│   └── index.js          # Access token verification
├── services/
│   └── index.js          # Cookie utility functions
├── .env.example
├── .gitignore
├── index.js               # Main Express server
├── package.json
├── vercel.json
└── README.md

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📄 License

This project is for educational purposes. Feel free to fork and use for your own learning or demo needs.

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