net-cat

A TCP-based group chat server written in Go, modelled after the NetCat (nc) utility.

Overview

Net-Cat runs as a TCP server that accepts multiple client connections. Clients connect using the standard nc command and can send messages to the group in real time. The server handles join/leave notifications, message history, and concurrent connections safely.

Usage

$ ./TCPChat                        # Listens on default port 8989
$ ./TCPChat 2525                   # Listens on selected port 2525. Accepts ports 0-65535

Connecting as a Client

$ nc <host-ip> <port>

Features

• TCP server accepting up to 10 simultaneous clients
• Messages are timestamped and identified by sender: [2020-01-20 15:48:41][name]:message
• New clients receive full message history on join
• All clients are notified when someone joins or leaves
• Empty messages are not broadcast
• Client disconnection does not affect other clients
• Concurrent connections handled safely with goroutines, channels and mutexes

Connecting from Another Machine

All machines must be on the same local network. Find the server machine's local IP with:

$ ip a

Then connect from another machine:

$ nc 192.168.x.x <port>

Testing the program locally

Start the server on localhost

./TCPChat localhost <port>

Simulate different clients by opening different terminals

nc localhost <port>

Send messages from one client terminal to the other.