Multithreaded HTTP Server

A lightweight multithreaded HTTP server built in C++ using POSIX sockets and a thread pool. The server handles multiple client connections concurrently, serves static files over HTTP, determines the correct MIME type for responses, and logs incoming requests.

Features

• Multithreaded architecture using a fixed-size thread pool
• Concurrent handling of multiple client connections
• HTTP GET request parsing
• Static file serving from the www directory
• Automatic MIME type detection
• HTTP response generation (200 OK, 404 Not Found)
• Request logging
• Cross-platform socket support (Linux and Windows)

Technologies Used

• C++
• POSIX Sockets
• C++ Standard Library
• Multithreading (std::thread)
• Mutexes
• Condition Variables
• TCP/IP Networking

Project Structure

.
├── server.cpp         # Server initialization and client connection handling
├── threadpool.cpp     # Thread pool implementation
├── threadpool.h
├── utils.cpp          # HTTP request parsing and response utilities
├── utils.h
├── www/               # Static website files
│   ├── index.html
│   ├── style.css
│   └── ...
└── README.md

How It Works

1. Initialize the server socket.
2. Configure socket options (SO_REUSEADDR).
3. Bind the socket to the specified port.
4. Start listening for incoming client connections.
5. Create a thread pool with worker threads.
6. Accept incoming client connections.
7. Add each client connection as a task to the thread pool.
8. Worker threads process HTTP requests, serve files, and send responses.
9. Close the client connection after the response is sent.

HTTP Request Flow

Client
   │
   ▼
accept()
   │
   ▼
Thread Pool
   │
   ▼
handleClient()
   │
   ▼
parseRequest()
   │
   ▼
Requested File?
 ┌──────┴──────┐
 │             │
No            Yes
 │             │
404        Read File
 │             │
 └──────┬──────┘
        ▼
Generate HTTP Response
        │
        ▼
send()
        │
        ▼
Close Connection

Supported HTTP Methods

Currently supported:

• GET

Unsupported methods return an error response.

Response Types

• 200 OK
• 404 Not Found

Supported File Types

• HTML
• CSS
• JavaScript
• JSON
• TXT
• PNG
• JPG / JPEG
• GIF
• SVG

Unknown file types are sent as:

application/octet-stream

Build

Linux

g++ -std=c++17 -pthread server.cpp threadpool.cpp utils.cpp -o server

Windows (MinGW)

g++ -std=c++17 server.cpp threadpool.cpp utils.cpp -lws2_32 -o server.exe

Run

./server

The server starts listening on the configured port.

Open your browser and visit:

http://localhost:<PORT>

Replace <PORT> with the port configured in the source code.

Future Improvements

• HTTP POST support
• Persistent connections (Keep-Alive)
• Directory listing
• File upload support
• HTTPS using SSL/TLS
• Configuration file support
• Thread pool resizing
• HTTP/1.1 compliance improvements
• HTTP caching
• Better error handling

Learning Outcomes

This project helped strengthen understanding of:

• TCP/IP networking
• POSIX socket programming
• Client-server architecture
• HTTP protocol fundamentals
• Multithreading in C++
• Thread pools
• Mutexes and condition variables
• Synchronization
• Static file serving
• MIME type handling
• Resource management
• Concurrent server design

License

This project is intended for educational and learning purposes.