P2P File Sharing Application

Overview

This project implements a Peer-to-Peer (P2P) file sharing application. The system allows peers to discover each other, exchange file metadata, and transfer files in a decentralized network. The application leverages Java for its core logic, Java Swing for the graphical user interface (GUI), and Docker for deployment and testing across multiple simulated peers.

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Features

• File Sharing:
  • Share files across peers.
  • Exclude specific files or directories from sharing.
• File Downloading:
  • Search for available files in the network.
  • Restrict downloads based on file masks.
  • Download files in chunks from multiple peers.
• Network Discovery:
  • Broadcast and response mechanisms for peer discovery.
  • Dynamic routing through discovered peers.
• Decentralized Operation:
  • No central server; peers communicate directly.
  • Automatic route calculation and message forwarding.
• GUI Support:
  • User-friendly interface for managing shared files and downloads.
  • Visual representation of connected peers.
• Dockerized Deployment:
  • Simulate a multi-peer network using Docker containers.

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Project Structure

Core Modules

1. File Management:

   • FileManager.java: Handles file chunking, saving, merging, and listing shared files.
   • PeerFileMetadata.java: Represents metadata for shared files (e.g., filename, size, hash).

2. Network and Communication:

   • BroadcastManager.java: Manages peer discovery through broadcast messages.
   • DiscoveryMessage.java: Tracks routing and TTL (time-to-live) for discovery messages.
   • Peer.java & PeerNetworkInterface.java: Represent peers and their network interfaces.
   • FileTransferManager.java: Handles file chunk requests and transfers between peers.
   • NetworkUtils.java: Provides utility functions for network operations (e.g., subnet matching).

3. Message Handling:

   • Message.java: Interface for various message types.
   • FileChunkMessage.java: Encapsulates a file chunk and metadata for transfer.
   • PeerFileMetadataRequestMessage.java: Requests specific file chunks from a peer.

4. GUI Components:

   • MainFrame.java: Main application window.
   • FilesPanel.java: Interface for managing shared files and exclusions.
   • DownloadPanel.java: Interface for managing downloads and monitoring progress.
   • GUIUtils.java: Utility functions for GUI components.

5. Application Entry Point:

   • App.java: Initializes the application and manages thread execution.

Docker Setup

The project includes a Docker-based setup to simulate a multi-peer network. The docker-compose.yml file defines multiple peers connected through overlapping networks.

Below is a visual representation of the Docker network and peer setup:

• docker-compose.yml:
  • Defines multiple peer containers and their network connections.
  • Simulates a realistic P2P network using Docker networks.
• Dockerfile:
  • Builds the Java application environment.
• Makefile:
  • Simplifies Docker build and run commands.

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Installation and Setup

Prerequisites

• Java 17
• Docker and Docker Compose

Running with Makefile

• Start/Restart the docker containers and networks:

  make rebuild

• Clean up unused docker containers and networks:

  make clean

Running Without Makefile

1. Compile source codes.
2. Execute the application:

   java -cp out com.github.fevzibabaoglu.App

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Usage

GUI Application

1. Launch the Application:
   • Run the main class.
2. Set Up Shared Files:
   • Configure the source and destination folder in the Files panel.
   • Add exclusions if needed.
3. Search and Download Files:
   • Use the Download panel to browse available files.
   • Right-click on a file and select Download.

Docker Simulation

• Each container represents a peer.
• Files shared by peers are accessible through the Docker volumes configured in the docker-compose.yml file.
• Observe the peer discovery process in the logs.

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Technical Details

Networking

• Broadcast Mechanism:
  • BroadcastManager broadcasts DiscoveryMessage to find peers.
  • Forwarding ensures the message reaches peers within the TTL.
• File Transfer:
  • File chunks are transferred using FileChunkMessage.
  • Chunk requests are managed through PeerFileMetadataRequestMessage.

Multithreading

• Separate threads handle:
  • Broadcasting and listening for discovery messages.
  • File transfer requests and responses.

Docker Networks

• Simulates a P2P network with overlapping subnets.
• Each peer connects to multiple networks to mimic real-world scenarios.

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License

This project is open-source and released under the MIT License.