Chatr: A TCP-Based TUI Chatbot

This repository contains Chatr, a Text User Interface (TUI) chatbot that communicates over TCP. Built in Go, Chatr allows multiple clients to connect to a server and exchange messages in real-time through a command-line TUI. This project serves as the final assignment for the Network lecture under the guidance of Professor Hamid Haj Seyyed Javadi.

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Table of Contents

• Chatr: A TCP-Based TUI Chatbot
  • Table of Contents
  • Project Overview
  • Prerequisites
  • Installation
  • Usage
    • Running the Server
    • Running the Client
    • Environment Variables
    • TCP Settings
    • Interacting via TUI
  • Contributing
  • License
  • Contact

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Project Overview

Chatr is a client-server chat application written in Go that uses raw TCP sockets to send and receive messages. The project demonstrates practical networking concepts by:

• Establishing a persistent TCP connection between a server and multiple clients.
• Broadcasting messages from one client to all connected clients.
• Dynamically tracking and displaying online users in a TUI.
• Providing a fluid command-line interface experience.

Key features include:

• TUI-based chat client to send and receive messages.
• Server broadcasting to all connected clients in real-time.
• User list management (join and leave notifications).
• Configurable through environment variables or command-line flags.

This project is especially relevant to the Network lecture, as it highlights low-level TCP socket management and concurrency.

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Prerequisites

Before installing or running this project, make sure you have the following:

1. Go (1.21+ recommended)
   You can check your Go version with:

   go version

2. Git (to clone the repository).

3. Basic knowledge of TCP networking (ports, hosts, firewalls).

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Installation

Follow these steps to set up Chatr on your local machine:

1. Clone the repository:

   git clone https://github.com/itsmohammadheidari/chatr.git
   cd chatr

2. Initialize Go modules (optional if already present):

   go mod tidy

   This will download and verify all the required dependencies listed in go.mod and go.sum.

3. (Optional) Create a .env file in the project root if you want to override default configurations via environment variables. For example:

   HOST=127.0.0.1
   PORT=8080
   USERNAME=MyUsername

   Note: If you don' t create a .env file, Chatr will use the defaults (127.0.0.1:8080) or the values provided via flags.

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Usage

Running the Server

1. Navigate to the project directory:

   cd chatr

2. Start the server:

   go run main.go server

   Alternatively, if you have built the binary (e.g., go build -o chatr):

   ./chatr server

   By default, the server listens on 127.0.0.1:8080. You can override this via flags or environment variables.

3. Server logs: You'll see logs about new connections, disconnections, and server status on your terminal.

Running the Client

1. In a new terminal, navigate to the project directory again (or from anywhere if you have the binary in your PATH).

2. Run the client:

   go run main.go client

   Or using the built binary:

   ./chatr client

3. Provide a username (optional). If you want a custom username, you can either:

   • Set it in .env: USERNAME=yourname
   • Use a flag:

   go run main.go client --username yourname

   When the client starts, it will connect to the server and you will see a TUI displaying online users and chat messages.

Environment Variables

Chatr supports the following environment variables (through .env or your system environment):

• HOST (default: 127.0.0.1)
• PORT (default: 8080)
• USERNAME (default: Guest when using the client)

Each environment variable can also be overridden by command-line flags:

• --host or -H
• --port or -P
• --username or -u

TCP Settings

• Default Host: 127.0.0.1
  This means both client and server run on the localhost.
• Default Port: 8080
  If port 8080 is in use, choose another port (e.g., --port 9090) and ensure that both server and client match the same port.

If running on different machines, ensure that:

1. The server machine's firewall allows inbound connections on the chosen port.
2. The client can reach the server over the network.

Interacting via TUI

Once the client is running, you'll see:

• A User List panel on the left (or top, depending on your screen).
• The Chat Box displaying messages from you and other users.
• An Input Field at the bottom where you can type messages.

Sending Messages:

• Type your message in the input field.
• Press Enter to send the message.
• Watch the conversation scroll up in the Chat Box.

Exiting:

• Press Ctrl + C in the terminal that is running the client (or server).
• Or close the terminal window.

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Contributing

Contributions are highly encouraged! If you have any suggestions for improvements or encounter any bugs, please feel free to open an issue or submit a pull request.

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License

This project is licensed under the GNU General Public License v3.0. For more information, refer to the LICENSE file.

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Contact

For questions, feedback, or contributions, reach out via:

• Project Maintainer: Mohammad Heidari
• Email: [email protected]

Thank you for using Chatr!