Multi-Threaded Proxy Server with and without Cache

This project implements a multi-threaded proxy server in C, inspired by this Proxy Server project.

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Index

• Project Overview
• How to Run
• Demo
• Contributing

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Project Overview

Introduction

This project demonstrates how a proxy server handles client requests using multi-threading and caching to enhance performance.

Basic Working Flow:

Multi-threading Implementation:

• Semaphore is used instead of pthread_join() and condition variables for thread synchronization.
• sem_wait() and sem_post() don’t require thread IDs, making them simpler and more efficient.

Why This Project?

To understand:

• How client requests are processed by servers.
• Handling multiple client requests simultaneously.
• Concurrency control using locks and semaphores.
• Caching mechanisms and their impact on performance.

Proxy Server Benefits:

• Performance Boost: Reduces server load and speeds up requests.
• Access Control: Restricts specific websites.
• Anonymity: Masks client IP addresses.
• Security: Encrypts requests to prevent unauthorized access.

OS Components Used:

• Threading
• Locks
• Semaphores
• Caching (LRU algorithm)

Limitations:

• Multiple Client Responses: Each client’s response is cached separately, leading to incomplete website loading.
• Fixed Cache Size: Large websites may not fit in the cache.

Future Enhancements:

• Multiprocessing: Boost performance through parallelism.
• Content Filtering: Control access to specific websites.
• POST Requests: Extend support for different HTTP methods.

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How to Run

1. Clone the repository:

   git clone <repository-url>
   cd MultiThreadedProxyServerClient

2. Build the project:

   make all

3. Run the proxy server:

   ./proxy <port-number>

4. Test it by opening:
   http://localhost:<port>/https://www.cs.princeton.edu/

Notes:

• Linux Only: The proxy runs on Linux.
• Browser Cache: Disable browser caching for accurate testing.
• Without Cache: To disable caching, rename the Makefile entry from proxy_server_with_cache.c to proxy_server_without_cache.c.

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Demo

• First Access: If a website is opened for the first time, the cache will miss (url not found).
• Subsequent Access: The cache retrieves the data, and Data is retrieved from the cache is displayed.

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Contributing

Contributions are welcome! Feel free to submit pull requests.

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Enjoy coding! 🎉