Multithreaded HTTP Proxy Server

This is a multithreaded HTTP proxy server implemented in C. It supports caching of HTTP requests and responses using an LRU (Least Recently Used) eviction policy.

⚙ Features

• Multithreading with POSIX threads
• Thread synchronization using semaphores
• LRU caching mechanism
• Support for HTTP/1.0 and HTTP/1.1 GET requests
• Support for CONNECT method (allows HTTPS tunneling)
• Proper error handling and status codes
• Configurable port number

📦 Building

To get started, first clone the repository:

$ git clone https://github.com/ArshhAnsari/MultiThreadedWebProxyServer.git
$ cd MultiThreadedWebProxyServer

Then, to build the proxy server, simply run:

$ make

This will compile the proxy server executable.

🚀 Usage

Start the proxy server with an optional port number:

$ ./proxy_server [port]

If no port is specified, the default port 8080 is used.

Testing

You can test the proxy server using curl:

$ curl -v --proxy http://localhost:8080 http://example.com

Or configure your browser to use the proxy server:

• Address: localhost
• Port: 8080 (or your custom port)

📘 Documentation

• 🔍 Explanation.md: Covers the architecture, design decisions, and OS-level concepts used in building this project.
• 🎥 ProxyServerDemo.md: Walkthrough of test scenarios with commands and visual outputs.

⚠️ Limitations

• Only GET and CONNECT supported
• No SSL termination
• Limited to 400 concurrent connections

Credits and Acknowledgments 🙌

This project builds upon the HTTP parsing functionality from the reference Lovepreet Singh implementation. While the original code provided a basic structure, this version significantly enhances it with advanced features, including:

• Comprehensive Multithreading: Thread pool management with POSIX threads
• Enhanced Synchronization: Semaphores and mutexes for thread safety
• Full Protocol Support: HTTP + HTTPS tunneling via CONNECT
• LRU Caching System: Efficient cache with Least Recently Used eviction
• Browser Compatibility: Supports direct browser request formatting
• Infinite Loop Prevention: Avoids recursive proxy forwarding
• Improved Error Handling: Better HTTP status code reporting

These changes result in a robust, concurrent proxy server with efficient caching and reliable HTTPS support.

🪪 License

This project is freely available for educational purposes.