Opticom - Multi-Client Chat Server

Opticom is a high-performance, multi-client chat server built in C++ using low-latency and fast-optimized methods. This project was developed as part of the IT-227 Computer System Programming Course in the B.Tech ICT Branch.

Features

• Multi-client support: Handle multiple clients simultaneously using threading
• Real-time messaging: Broadcast messages to all connected clients
• Thread-safe: Uses mutex locks for safe concurrent access
• Cross-platform: Works on Linux, macOS, and other Unix-like systems
• Signal handling: Graceful shutdown with Ctrl+C
• Configurable port: Run on any available port
• Simple client: Included test client for easy testing

Architecture

The server uses:

• TCP sockets for reliable communication
• POSIX threads for handling multiple clients
• Mutex locks for thread-safe client management
• Signal handling for graceful shutdown

Building

Prerequisites

• C++11 compatible compiler (g++, clang++)
• POSIX-compliant system (Linux, macOS, etc.)
• Make utility

Compilation

# Build both server and client
make

# Or build individually
make opticom    # Server only
make client     # Client only

# Debug build
make debug

# Clean build artifacts
make clean

Usage

Starting the Server

# Run on default port (8080)
./opticom

# Run on custom port
./opticom 9090

# Or using make
make run
make run-port PORT=9090

Connecting Clients

# Connect to localhost on default port
./client

# Connect to specific server and port
./client 192.168.1.100 8080

# Or using make
make run-client
make run-client IP=192.168.1.100 PORT=8080

Testing Multiple Clients

1. Start the server: ./opticom
2. Open multiple terminal windows
3. Run clients in each terminal: ./client
4. Type messages in any client - they will be broadcast to all others

Project Structure

Opticom/
├── opticom.cpp      # Main server implementation
├── client.cpp       # Test client implementation
├── Makefile         # Build configuration
├── README.md        # This file
└── LICENSE          # License file

Technical Details

Server Components

• ChatServer class: Main server implementation
• Socket management: TCP socket creation and binding
• Client handling: Thread-per-client architecture
• Message broadcasting: Send messages to all connected clients
• Client management: Add/remove clients safely

Client Components

• ChatClient class: Simple client implementation
• Connection management: Connect to server and maintain connection
• Message handling: Send and receive messages
• Threading: Separate thread for receiving messages

Thread Safety

• Uses std::mutex to protect shared client list
• lock_guard for automatic mutex management
• Thread-safe client addition/removal

Installation

# Install to system
make install

# Uninstall
make uninstall

Signal Handling

The server handles SIGINT (Ctrl+C) and SIGTERM signals for graceful shutdown:

• Closes all client connections
• Cleans up resources
• Exits cleanly

Error Handling

• Socket creation and binding errors
• Client connection failures
• Message sending failures
• Graceful client disconnection handling

Performance Considerations

• Uses non-blocking socket operations where possible
• Efficient message broadcasting
• Minimal memory allocation
• Thread-per-client model for simplicity

License

See LICENSE file for details.

Course Information

This project was developed as part of IT-227 Computer System Programming Course in the B.Tech ICT Branch, focusing on:

• Socket programming
• Multi-threading
• System programming concepts
• Network communication protocols