Peer-to-Peer Chat

This project implements a chat system between different peers using UDP, TCP. Each node can connect to the network, discover other nodes, and communicate with them. The application allows receiving and sending messages through a web interface and API.

Installation and Running

1. Install Dependencies:

• Install Node.js and npm from the Node.js website.
• Clone this repository to your computer.

2. Install npm Packages

• Navigate to the project directory and run npm i to install all necessary packages.

3. Configuration:

• Set up the configuration file config.json according to your needs.
• Your peer-id will be by default your name of device

4. Running:

• Open a terminal and navigate to the project directory.
• Start the application with the command npm start.

5. Running as a Service

• If you want to run the application as a service on Debian, create a chat.service file in /etc/systemd/system and modify it to look like the code below, replacing user with the user under which you want to run the service and WorkingDirectory with the path to your project.
• Run the command sudo systemctl daemon-reload to reload the systemd daemon configuration.
• Then you can use sudo systemctl start chat to start the service and sudo journalctl -fu chat to view the logs.

Configuration file chat.service:

[Unit]
Description=P2P chatting app (2)
After=network.target
[Service]
Type=simple
User=<user>
WorkingDirectory=<path_to_project_folder>
ExecStart=npm start
Restart=always
Environment=NODE_ENV=production
[Install]
WantedBy=multi-user.target

Usage

1. UDP Discovery

• Upon starting the application, a node automatically connects to the network and regularly sends UDP Discovery messages to discover other nodes.
• Responses to these queries will contain a list of available nodes in the network.

2. TCP Protocol

• After discovering other nodes via UDP, a node establishes a persistent TCP connection with each of them and saves it.
• Upon establishing a connection, it performs a handshake and receives message history from the peer.
• It can then send and receive messages using TCP connections.
• Additionally, a TCP server is created to listen, and upon incoming handshake, it returns all its messages.

3. Web API

• The application provides a simple HTTP API and interface for reading and sending messages.
• GET /messages - returns all messages in json
• GET /send?message=<text> - sends a message where
• GET / - a simple interface for sending and displaying messages

Additional Information

• The project is implemented in Typescript and runs on Node.js.
• Express.js is used for the web API.
• Each peer has a unique ID, which can be set in config.json as my_peer_id.
• Messages are identified using timestamps.
• An array in RAM is used for storing message history.
• The application logs events and errors using system logging.
• All non-original content can be found in /src/vendor.
• All logs are placed in /logs

License

This project is licensed under the MIT License. Details can be found in the LICENSE file.