HTTP Caching Proxy

A lightweight HTTP proxy server implemented in Java that provides caching capabilities using an LRU (Least Recently Used) caching strategy.

Features

• HTTP proxy server with response caching
• LRU (Least Recently Used) cache implementation
• Configurable cache capacity (default: 3 entries)
• Custom port configuration
• Origin server URL configuration
• Cache clearing functionality
• Cache hit/miss tracking via response headers

Requirements

• Java 17 or higher
• Maven 3.8+
• Windows/Linux/macOS

Building the Project

mvn clean package

Usage

Run the proxy server using the following command:

java -jar target/caching-proxy-1.0-SNAPSHOT.jar --port <port> --origin <origin-url>

Command Line Arguments

Argument	Description	Required	Default
--port	Port number for the proxy server	No	4000
--origin	Origin server URL (must start with http:// or https://)	Yes	-
--clear-cache	Clear the cache and exit	No	false

Examples

Start the proxy server on port 3000:

java -jar target/caching-proxy-1.0-SNAPSHOT.jar --port 3000 --origin https://api.example.com

Clear the cache:

java -jar target/caching-proxy-1.0-SNAPSHOT.jar --clear-cache

How It Works

1. The proxy server accepts incoming HTTP requests
2. For each request, it:
   • Checks if the response is in the cache
   • If found (HIT): Returns cached response with X-Cache: HIT header
   • If not found (MISS):
     • Forwards request to origin server
     • Caches the response
     • Returns response with X-Cache: MISS header
3. Uses LRU eviction policy when cache reaches capacity

Project Structure

src/main/java/org/muchiri/
├── Main.java           # Entry point and argument handling
├── Server.java         # Proxy server implementation
├── ProxyHandler.java   # Request/response handler
├── Cache.java          # Cache interface
├── LRUCache.java       # LRU cache implementation
└── ArgType.java        # Command line argument types

Contributing

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request