Busy Highway

A simple and efficient rate limiting library for Node.js that implements various rate limiting algorithms.

Installation

npm install @proudmars/busy-highway

Features

• Multiple rate limiting algorithms:
  • Token Bucket
  • Leaky Bucket
  • Fixed Window Counter
  • Sliding Window Counter
  • Sliding Window Log

Usage

import { 
  TokenBucket,
  LeakyBucket,
  FixedWindowCounter,
  SlidingWindowCounter,
  SlidingWindowLog
} from '@proudmars/busy-highway';

// Token Bucket Example
const tokenBucket = new TokenBucket(10, 2); // 10 tokens, refills 2 tokens/second
if (tokenBucket.allowRequest()) {
  // Process request
}

// Leaky Bucket Example
const leakyBucket = new LeakyBucket(5, 1); // 5 requests capacity, leaks 1 request/second
if (leakyBucket.allowRequest()) {
  // Process request
}

// Fixed Window Example
const fixedWindow = new FixedWindowCounter(100, 60); // 100 requests per 60 seconds
if (fixedWindow.allowRequest()) {
  // Process request
}

// Sliding Window Counter Example
const slidingWindow = new SlidingWindowCounter(100, 60); // 100 requests per 60 seconds
if (slidingWindow.allowRequest()) {
  // Process request
}

// Sliding Window Log Example
const slidingLog = new SlidingWindowLog(100, 60); // 100 requests per 60 seconds
if (slidingLog.allowRequest()) {
  // Process request
}

Algorithm Details

Token Bucket

• Maintains a bucket of tokens that refills at a fixed rate
• Each request consumes one token
• Good for handling bursts while maintaining average rate

Leaky Bucket

• Requests enter a fixed-capacity bucket
• Requests leak out at a constant rate
• Good for smoothing out traffic spikes

Fixed Window Counter

• Counts requests in fixed time windows
• Resets counter at window boundaries
• Simple but can allow twice the rate at window boundaries

Sliding Window Counter

• Uses weighted sliding window approach
• Smooths out boundary conditions of fixed windows
• Good balance of accuracy and memory usage

Sliding Window Log

• Keeps track of timestamp of each request
• Most accurate but higher memory usage
• Good for precise rate limiting

Development

# Install dependencies
pnpm install

# Build the project
pnpm build

# Run linting
pnpm lint

# Run in development mode with watch
pnpm dev

License

MIT © ProudMars