TorrentUtils

TorrentUtils is a C# rewrite of airium/TorrentUtils. It provides BitTorrent metadata APIs for parsing, writing, hashing, top-level metadata rewriting, and payload verification.

The library is focused on BEP 3 / v1 torrent metadata. It also exposes a lightweight meta version probe so callers can identify v2 metadata before choosing a parsing path.

Install

dotnet add package TorrentUtils

Basic Usage

Read metadata and compute the v1 info hash:

using TorrentUtils;

using var torrent = new Torrent();
torrent.ReadTorrentFile("sample.torrent");

Console.WriteLine(torrent.Name);
Console.WriteLine(torrent.ComputeInfoHashHex());

foreach (var file in torrent.FileList)
{
    Console.WriteLine($"{file.RelativePath} {file.Size}");
}

Create a v1 torrent from a file or directory:

using TorrentUtils;

using var torrent = new Torrent(pieceLength: 4 * 1024 * 1024);
torrent.SetTrackerList(["https://tracker.example/announce"]);
torrent.SetCreatedBy("TorrentUtils");

await torrent.LoadFromPathAsync(new DirectoryInfo("payload"));
torrent.WriteTorrentFile("payload.torrent");

Verify payload bytes against an existing torrent:

using TorrentUtils;

using var torrent = new Torrent();
torrent.ReadTorrentFile("payload.torrent");

IReadOnlyList<int> failedPieces = torrent.Verify("payload");

Probe the torrent metadata version:

using TorrentUtils;

int version = TorrentVersion.ReadMetaVersionFromFile("sample.torrent");
bool isV2 = TorrentVersion.IsV2FromFile("sample.torrent");

Rewrite top-level metadata without changing the info dictionary:

using TorrentUtils;

var update = new TorrentTopLevelUpdate();
update.SetComment("Updated comment");
update.SetCreatedBy("TorrentUtils");

TorrentTopLevelRewriter.RewriteFile("input.torrent", "output.torrent", update);