P2P-File-Transfer | Java, Netty, Protobuf

It is an unstructured peer-to-peer file-sharing network using Java 21 and Netty 4

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How to Run

1. Clone the repository:

   git clone https://github.com/halcyonsdev/p2p-file-transfer.git

2. Navigate to the project directory:

   cd p2p-file-transfer

3. Build the project:

   mvn clean install

4. Run the application:

   java -DpeerName=peer -jar target/p2p-file-transfer.jar --config=config/config.properties --peerName=peer --bindPort=8080

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Features

1. Peer-to-Peer Network

• Supports a decentralized network where each peer can directly communicate with others.
• Uses TCP connections managed through Netty.

2. File Transfer

• Allows peers to request and share files efficiently.
• Supports transferring files in chunks to handle large files.

3. Keep-Alive Mechanism

• Periodic pings KeepAliveMessage are sent to ensure the connection between peers remains active.
• Timeouts trigger reconnection attempts or removal of inactive peers.

4. Protobuf-Based Communication

• Defines a flexible communication protocol using Protocol Buffers (Protobuf).
• Messages include handshakes, file requests, and other network events.

5. Ping-Pong System

The ping-pong system is a critical component of the network that:

• Sends periodic ping messages to discover and verify active peers.
• Receives pong responses from peers, which include their metadata.
• Times out inactive peers and removes them from the network.
• Notifies other components about discovered peers, allowing dynamic adjustment of connections.

Workflow:

1. Ping: Each peer periodically sends a PingMessage to its connected peers.
2. Pong: Upon receiving a ping, peers respond with a PongMessage that includes their details.
3. Timeout Handling: If no pong is received within a specific timeout period, the pinging peer assumes the target is inactive and cleans up resources associated with that peer.

6. Auto-Connection Management

• Automatically connects to available peers when connection slots are free.
• Prioritizes unconnected peers for establishing new connections.

7. Custom Configuration

• Configuration can be provided via a .properties file.
• Properties include settings for connection limits, ping intervals, and timeout durations.

8. Netty-Based Networking

• High-performance networking with Netty as the underlying framework.
• Supports asynchronous communication for scalability.

9. Logging

• Provides detailed logs for network events, file transfers, and system actions.

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How It Works

1. Startup: Each peer starts and loads its configuration from the provided .properties file or by default properties.
2. Handshake: Peers perform an initial handshake to establish connections and exchange metadata.
3. Ping-Pong: The ping-pong system ensures active peers are discovered and maintains a healthy network.
4. File Requests: Peers can request files from others by sending a GetFilesRequest message and receiving the response with available file names.
5. File Transfer: File chunks are sent between peers upon request.

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License

This project is licensed under the MIT License. See the LICENSE file for details.