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Rate Limiter with Token Bucket Algorithm

This project demonstrates the implementation of a Rate Limiter using the Token Bucket Algorithm in a 3-layer architecture. The architecture consists of the following components:

• Frontend: Built with React and Vite.
• Middleware: Handles the rate limiting logic using a Token Bucket Algorithm implemented with Redis and Lua scripts to address race conditions.
• Backend: A lightweight Express.js server that responds to client requests.

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Features

• Rate Limiting: Controls the rate of incoming requests using the Token Bucket Algorithm.
• Race Condition Handling: Utilizes Lua scripts in Redis to ensure atomic operations in the rate limiter.
• Response Headers: Sends appropriate headers such as X-Ratelimit-Limit, X-Ratelimit-Remaining, and X-Ratelimit-Retry-After for better client-side handling.
• Scalable Design: Modular structure suitable for high-traffic systems.
• Demonstration: Includes mock scenarios to demonstrate the functionality of rate limiting and race condition management.

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Installation

1. Clone the repository:

   git clone https://github.com/thabir303/rate-limiter.git
   cd rate-limiter

2. Install dependencies for backend and frontend:

   # Backend
   cd backend
   npm install
   
   # Frontend
   cd ../frontend
   npm install

3. Setup environment variables: Create a .env file in the root directories of the backend and middleware, and configure the following:

   REDIS_HOST=localhost
   REDIS_PORT=6379
   REDIS_PASSWORD=your_password (if applicable)

4. Start Redis: Ensure Redis is running on your system.

5. Run the application:

   # Backend
   cd backend
   npm start
   
   # Frontend
   cd ../frontend
   npm run dev

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Usage

• Rate Limiting:

  • The middleware intercepts all requests to the backend.
  • The rate limiter tracks tokens using Redis and processes requests based on availability.

• Race Condition Handling:

  • Lua scripts ensure atomic operations in Redis to handle concurrent requests efficiently.

• Response Headers:

  • The middleware sends the following headers:
    • X-Ratelimit-Limit: Total requests allowed in the window.
    • X-Ratelimit-Remaining: Remaining requests in the current window.
    • X-Ratelimit-Retry-After: Time to wait before the next request.

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