GOP2P

A peer-to-peer chat and file sharing system using UDP.

Architecture

The system consists of three main components:

graph TD
    subgraph "Public Internet"
        RS[Relay Server]
    end
    subgraph "Local Network A"
        CA[Client A] --- WA[Web UI A]
    end
    subgraph "Local Network B"
        CB[Client B] --- WB[Web UI B]
    end
    CA -.->|Register/Discover| RS
    CB -.->|Register/Discover| RS
    CA <==>|UDP Hole Punching| CB
    CA <==>|P2P Chat / File Share| CB

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• Relay Server: A public UDP server that coordinates NAT traversal and peer discovery.
• Client: A Go backend that handles identity management, P2P networking, messaging, and file transfers. It also serves a local web interface.
• Web UI: A React-based frontend that communicates with the client via WebSockets and REST.

Project Structure

.
├── client/          # Go Client source code
├── server/          # Relay Server source code
├── protocol/        # Shared P2P communication protocols
├── web/             # React Frontend source code

Build Instructions

Prerequisites

• Go (v1.24+)
• Node.js & npm (for building the web assets)

Build All

make all

This command will:

1. Build the frontend assets (web/dist).
2. Build the Go client, embedding the frontend assets into the binary.
3. Build the Go server.
4. Place all binaries in the bin/ directory.

Running the System

1. Start the Relay Server

./bin/server
# Listens on 0.0.0.0:8080 by default

2. Start Clients

Open two terminal windows and start two clients:

Client A:

./bin/client -name Alice -api 8081 -udp 3001

Client B:

./bin/client -name Bob -api 8082 -udp 3002

3. Use the Interface

1. Open the UI: http://localhost:8081 (Client A) and http://localhost:8082 (Client B).
2. Connect peers.
3. Start chatting or sharing files!