PeerSharp 1.0.0

PeerSharp

PeerSharp is a high-performance, modern BitTorrent engine for .NET 10+.

Key Features

• Full BEP Support: Implements 20+ BitTorrent Extension Protocols (see Supported BEPs).
• Hybrid Networking: Native support for both TCP and uTP (BEP 29) with automatic congestion control.
• DHT & Peer Discovery: Full Mainline DHT (BEP 5), Local Service Discovery (BEP 14), Peer Exchange (PEX), and UDP/HTTP Tracker support.
• Magnet Links: Fast metadata exchange (BEP 9) allowing torrent starts from magnet links alone.
• Streaming Engine: Integrated HTTP streaming server for real-time media playback while downloading.
• Protocol Encryption: MSE (Message Stream Encryption) with configurable enforcement modes.
• NAT Traversal: UPnP, NAT-PMP, and Holepunch (BEP 55) for connectivity behind NATs.
• Bandwidth Control: Per-torrent and global upload/download/disk I/O rate limiting.
• Proxy Support: SOCKS5 and HTTP proxy support with authentication.
• IP Blocklist & GeoIP: Block peers by IP range or country.
• Optimized I/O: Zero-copy Bencoding, pooled buffers, block caching, and asynchronous disk I/O designed for high-throughput scenarios.
• Enterprise-Grade Testing: Rigorous validation using Microsoft Coyote for concurrency testing, architecture tests for design integrity, and fuzzing for robustness.

Getting Started

Installation

dotnet add package PeerSharp

Requires .NET 10.0 or later.

Basic Usage

using PeerSharp.Clients;
using PeerSharp.Config;
using PeerSharp.Core;

// Initialize the engine
var engine = ClientEngineFactory.Create();
await engine.InitializeAsync();

// Add a torrent
var torrentFile = TorrentFile.Load("my_file.torrent");
var options = new AddTorrentOptions("./downloads");
var torrent = await engine.AddTorrentAsync(torrentFile, options);

// Or add from a magnet link
var magnet = MagnetLink.Parse("magnet:?xt=urn:btih:...");
var torrent2 = await engine.AddMagnetAsync(magnet, new AddTorrentOptions("./downloads"));

Monitoring Progress

PeerSharp supports two models for monitoring: a polling-based alert queue and per-torrent event callbacks.

// Option 1: Polling alerts
await foreach (var alert in engine.Alerts.GetAlertsAsync())
{
    Console.WriteLine(alert);
}

// Option 2: Per-torrent event callbacks via builder
var events = new TorrentEventsBuilder()
    .OnProgressChanged((torrent, progress) =>
        Console.WriteLine($"Progress: {progress}"))
    .OnFinished((torrent, selectedOnly) =>
        Console.WriteLine($"Finished: {torrent}"))
    .Build();

var options = new AddTorrentOptions("./downloads") { Events = events };

Streaming

// Open a seekable stream for media playback
var stream = await torrent.OpenStreamAsync(fileIndex: 0);

Supported BEPs

PeerSharp aims for high compatibility with the BitTorrent ecosystem:

Architecture

PeerSharp is designed with a modular, interface-driven architecture:

• ClientEngine: The central orchestrator managing multiple torrent sessions.
• PiecePicker: Advanced logic for piece selection (rarest-first, sequential, streaming modes).
• Storage: Abstracted disk I/O layer with sparse file support, block caching, and file handle pooling.
• BEncoding: A high-performance, allocation-aware parser and writer for the BitTorrent data format.
• Alert System: A centralized event bus with both polling and callback models for real-time monitoring.
• NetworkManager: TCP and uTP connection handling with protocol encryption.
• DhtManager: Full Kademlia-style distributed hash table with security extensions.

License

Distributed under the MIT License. See LICENSE for more information.