chat-app

A simple client-server chat application built with Winsock2 & Win32 API. This project demonstrates low-level network programming and custom GUI framework development, helping to understand how libraries like wxWidgets and Qt work under the hood.

Features

• Client-server architecture with TCP sockets
• Custom event-driven GUI framework ("Engine")
• Layer-based application architecture
• Template-based protocol serialization
• Multi-threaded server supporting multiple concurrent clients
• Custom widget system (Panel, Button, TextInput)

Table of Contents

• Requirements
• Dependencies
• Project Structure
• Installation
• Building
• Usage
• Architecture
• Testing
• Known Limitations
• License

Requirements

• C++17 compiler (MSVC recommended)
• Windows OS
• CMake 3.10+

Dependencies

• Google Test (included as submodule)
• Winsock2 (ws2_32.lib)
• Win32 API

Project Structure

chat-app/
├── app/                    # Main application
│   ├── src/               # Chat app implementation
│   └── include/app/       # Chat app headers
├── engine/                # Custom GUI framework
│   ├── include/engine/    # Engine headers (Window, Panel, Events, Layers)
│   └── src/               # Engine implementations
├── network_core/          # Networking library
│   ├── include/           # Network headers (Socket, Connection, Protocol)
│   ├── src/               # Network implementations
│   └── test/              # Network unit tests
└── lib/                   # Third-party libraries
    └── googletest/        # Google Test framework

Installation

Clone the repository with submodules:

git clone https://github.com/benofthebens/chat-app.git --recurse-submodules
cd chat-app

If you already cloned without submodules:

git submodule update --init --recursive

Building

Using Visual Studio (MSVC)

# Configure
cmake --preset x64-debug

# Build
cmake --build out/build/x64-debug

For release builds:

cmake --preset x64-release
cmake --build out/build/x64-release

Using MinGW

# Configure
cmake --preset mingw-debug

# Build
cmake --build out/build/mingw-debug

Usage

The project builds two executables:

1. Chat Application (App.exe)

The main GUI client application with integrated networking.

./out/build/x64-debug/app/App.exe

• Type messages in the text input box
• Click the button to send messages
• Messages from other clients appear in message boxes

2. Standalone Server (Server.exe)

A dedicated server for hosting chat sessions.

./out/build/x64-debug/app/Server.exe

The server listens on 127.0.0.1:8080 and broadcasts messages to all connected clients.

Running a Chat Session

1. Start the server:

   ./out/build/x64-debug/app/Server.exe

2. Launch one or more client instances:

   ./out/build/x64-debug/app/App.exe

3. Clients automatically connect to 127.0.0.1:8080 on startup

Architecture

Engine (Custom GUI Framework)

A custom event-driven GUI framework built on Win32 API:

• Application: Main application loop and layer management
• Window: Top-level window with event callbacks
• Panel: Base widget class supporting hierarchical UI
• Layer: Application state/screen abstraction
• Event System: Type-safe event dispatching (Window, Custom events)
• GraphicsContext: Rendering abstraction over Win32 GDI

Widgets:

• Button: Clickable button with callback support
• TextInput: Single-line text input field

Network Core

Generic networking library with template-based protocol handling:

• Socket: Low-level Winsock2 wrapper
• Connection: Server and Client connection abstractions
• ProtocolHandler: Template-based serialization/deserialization
• Session: Manages individual client sessions
• ApplicationServer/Client: High-level server and client implementations

Chat Application

Combines Engine and NetworkCore using a layered architecture:

• ChatAppLayer: Handles UI rendering and chat events
• NetworkLayer: Manages network communication in separate thread
• Custom Events: MessageSendEvent, MessageReceiveEvent

Testing

Run the network core tests:

# Using CTest
ctest --test-dir out/build/x64-debug/network_core/test

# Or run directly
./out/build/x64-debug/network_core/test/NetworkCoreTests.exe

Known Limitations

• Hardcoded server address (127.0.0.1:8080)
• No encryption or authentication
• Windows-only (uses Win32 API)
• Basic error handling
• Fixed message size (1024 bytes)

Future Improvements

• Configurable server IP/port
• Chat history view with scrollable message list
• User nicknames and avatars
• Persistent message storage
• Reconnection logic
• Cross-platform support (abstract GUI layer)
• Better visual design and UX
• Private messaging

License

Apache License 2.0 - See LICENSE.txt for details.

Learning Objectives

This project was built to understand:

• How GUI frameworks abstract Win32 API
• Network programming with Winsock2
• Event-driven architectures
• Layer-based application design
• Template metaprogramming for protocols