C++ Socket Chat

Video Demo

Screen.Recording.2026-05-25.at.7.41.32.PM.mov

Project Overview

This is a learning project for socket programming in C++.

References used:

• Beej’s Guide to Network Programming
• https://www.learncpp.com/

The project is a simple chat application where users can:

• connect to a server.
• create chats.
• join existing chats.
• and exchange messages in real time.

Server Architectures

I implemented two server approaches:

1. Thread-pool server (servert)

   • Uses a thread pool to process client tasks concurrently.

2. poll() event-driven server (serverp)

   • Uses poll() to handle multiple clients in a single event loop.
   • Better suited for scalable I/O handling.
   • Supports broadcasting updates (for example, chat list updates and message updates).

Client Architecture

The client is multithreaded:

• one thread reads user input.
• one thread listens for server updates.

This allows the client to keep chat state updated in real time while the user is typing.

Protocol (Current Format)

Communication uses a simple custom TCP protocol framed by a 4-byte length header (handled by Utils::sendAll / Utils::receiveAll).

Client Requests

• List chats:
  • GET /chats
• Get one chat (messages):
  • GET /chat/<chat_name>
• Create chat:
  • POST /chat/<chat_name>
• Send message:
  • POST /message/<chat_name>/username:<username>{<message>}

Server Responses

Common response patterns:

• Chat list:
  • /chats/ followed by one chat name per line
• Single chat content:
  • /chat/<chat_name> followed by one message per line
• Errors / status:
  • Chat not found
  • Chat already exists
  • Invalid request
  • OK

Notes

• The protocol is intentionally lightweight for learning purposes.
• Request parsing currently expects valid formats (especially for POST /message).

Build and Run

1) Build

make

2) Run one server (choose one)

Thread-pool server:

./servert

poll() server:

./serverp

3) Run clients (in one or more other terminals)

./client

You can run multiple client instances to simulate multiple connected users.