🧵 Synchronized Multithreaded HTTP Server

A high-performance, thread-safe HTTP/1.1 server in pure C that supports concurrent GET and PUT requests. Designed for speed, safety, and correctness, this server uses a synchronized work queue, thread pool, and fine-grained file-level locking.

🚀 Features

• 🧵 Multithreaded: Thread pool for concurrent request handling
• 🧺 Synchronized Work Queue: Producer-consumer model using mutex and semaphores
• 🔐 File-Level Concurrency: Read-write locks ensure safe GET/PUT access
• 📄 HTTP/1.1 Support: Parses headers, body, Content-Length, Request-Id
• 🛠️ Robust Error Handling: Handles malformed input, system errors, EINTR
• 🪵 Thread-Safe Logging: Logs all requests with status codes and IDs
• 🧼 Graceful Shutdown: Signal handlers for SIGINT/SIGTERM cleanup

📦 Project Structure

.
├── httpserver.c     # Main server source code
├── Makefile         # For building the server
├── README.md        # This file
├── test_repo.sh     # Sample test script
├── load_repo.sh     # Optional script to load test files
├── config.json      # Sample config (optional)
├── output.txt       # Sample output (optional)
├── error.txt        # Sample error log (optional)
└── workloads/       # Test files directory (optional)

🔧 Build Instructions

make

Or compile manually:

gcc -pthread -o httpserver httpserver.c

▶️ Usage

./httpserver -t <num_threads> <port>

Example:

./httpserver -t 4 8080

📬 Sample Requests

PUT Request

curl -X PUT -H "Request-Id: 123" --data "hello world" http://localhost:8080/hello.txt

GET Request

curl -X GET -H "Request-Id: 456" http://localhost:8080/hello.txt

🧪 Testing

Run all your test cases:

./test_repo.sh

🧹 Graceful Shutdown

The server handles Ctrl+C or SIGTERM, cleans up threads and locks, and shuts down cleanly.

📚 Concepts Demonstrated

• Thread pools and pthreads
• Producer-consumer queue using mutex/semaphore
• Per-file fine-grained locking (readers-writer locks)
• HTTP/1.1 protocol parsing and validation
• Memory safety and resource cleanup
• Signal handling in concurrent systems