Streamix - High-Performance HTTP File Server

A high-performance HTTP/1.1 server written in modern C++ that efficiently serves large files using zero-copy system calls and modern C++ features. The server implements a subset of HTTP/1.1 with support for GET requests and proper error handling.

Key Features

• High Performance: Utilizes zero-copy sendfile() for maximum throughput
• Multi-threaded: Handles multiple clients concurrently with thread-per-connection model
• Resource Safe: RAII for automatic resource management
• Modern C++: Written in C++17 with clean, maintainable code
• Efficient: Minimal memory copies and system calls
• Secure: Basic HTTP request validation and proper error handling
• HTTP/1.1: Implements essential HTTP/1.1 features

Prerequisites

• Linux (uses Linux-specific system calls like sendfile)
• C++17 compatible compiler (g++ 9+ or clang++ 10+ recommended)
• CMake 3.12+ (for building)
• Development tools (make, gcc, etc.)

Quick Start

# Build
make

# Generate a 10GB test file
make test-file

# Run the server (requires root for privileged ports < 1024)
make run

# In another terminal, test the server
curl -I http://localhost:8080/

Advanced Usage

# Custom test file size (e.g., 5GB)
make test-file TEST_SIZE=5

# Clean build artifacts
make clean

# Format code (requires clang-format)
make format

# Build with debug symbols
make debug

Testing

Basic Test

# Check server headers using GET
curl -I http://localhost:8080/

# Expected response:
# HTTP/1.1 200 OK
# Content-Length: <file_size_on_server> bytes
# Connection: close
# Content-Type: application/octet-stream

Download Test

# Download with progress bar
curl --progress-bar -o downloaded_file http://localhost:8080/

# Test with non-GET method
curl -X POST -I http://localhost:8080/
# Expected: 405 Method Not Allowed

Concurrent Connections

# Test with multiple concurrent connections
for i in {1..10}; do
  curl -s http://localhost:8080/ > /dev/null &
done
wait

Architecture

Core Components

1. Socket Class

   • RAII wrapper for socket operations
   • Handles connection lifecycle
   • Implements move semantics for safe resource transfer

2. File Class

   • RAII wrapper for file operations
   • Provides file size information
   • Ensures proper file descriptor cleanup

3. Thread-per-Connection Model

   • Creates a new thread for each client connection
   • Uses POSIX threads for handling connections
   • Implements proper resource cleanup in each thread

Data Flow

1. Server starts and binds to the configured port
2. Main thread accepts incoming connections in a loop
3. For each new connection:
   • Creates a new thread to handle the client
   • The new thread:
     • Sends HTTP headers with proper Content-Length
     • Streams file content using zero-copy sendfile()
     • Cleans up resources when done
   • Main thread continues accepting new connections

Performance Optimizations

• Zero-copy Transfers: Uses sendfile() for direct file-to-network transfers
• Efficient Memory: RAII for automatic resource management
• Chunked Sending: Configurable chunk sizes (default: 8MB) for optimal throughput
• Error Handling: Robust error handling with proper resource cleanup
• Threading: Simple thread-per-connection model (note: for production use, consider a thread pool for better scalability)

Areas for Improvement

Testing Infrastructure

• Unit Tests: Add Google Test framework for testing individual components
  • Socket creation and error handling
  • File handling and cleanup
  • HTTP response formatting
• Integration Tests: Test client-server interactions
  • Multiple concurrent connections
  • Partial file transfers
  • Error conditions and recovery

Logging and Monitoring

• Structured Logging
  • Add timestamps and log levels (INFO, WARN, ERROR)
  • Log client connections and disconnections
  • Track transfer statistics (bytes sent, transfer rate)
• Metrics Collection
  • Track active connections
  • Monitor memory usage
  • Measure request/response times

Security Enhancements

• Authentication
  • Basic Auth or JWT token validation
  • Rate limiting to prevent abuse
  • IP whitelisting/blacklisting
• TLS/HTTPS Support
  • Add OpenSSL integration
  • Support for HTTP/2
  • Certificate management

Performance Optimizations

• Connection Pooling
  • Replace thread-per-connection with thread pool
  • Configurable pool size based on CPU cores
  • Queue management for high load
• Range Requests
  • Support HTTP Range headers
  • Enable resumable downloads
  • Handle multiple range requests

Additional Features

• Directory Browsing
  • List files in a directory
  • Support for index.html fallback
  • File size and modification time display
• Graceful Shutdown
  • Handle SIGTERM/SIGINT
  • Complete ongoing transfers
  • Clean up resources properly