static void Main(string[] args)
{
var peerId = "-YD0010-DEV CLIENT..";
// Load a sample torrent file
var fileContents = File.ReadAllBytes(@"insert-sample-torrent-path-here.torrent");
// Get an object dictionary of the file contents
var objects = BEncode.DecodeObject(new DataIndex(fileContents));
// Parse the contents of the BEncode decoding
var torrent = new Torrent(objects);
Tracker.AnnounceRequest(peerId, torrent);
TestEncoding(objects, fileContents);
TestPieceHashing(torrent);
System.Console.ReadLine();
}
/// <summary>
/// Make a request to the announce URL.
/// </summary>
/// <param name="peerId">This client's peer ID.</param>
/// <param name="torrent">The torrent information.</param>
public static void AnnounceRequest(string peerId, Torrent torrent)
{
var builder = new UriBuilder(torrent.Announce);
var query = HttpUtility.ParseQueryString(builder.Query);
query["peer_id"] = peerId;
query["port"] = "26644";
query["uploaded"] = "0";
query["downloaded"] = "0";
query["left"] = torrent.TorrentInfo.FileInfos.Sum(i => i.Length).ToString();
query["compact"] = "1";
query["event"] = "started";
// Add info hash manually since we had to manually encode it
var info_hash = Encoding.UTF8.GetString(WebUtility.UrlEncodeToBytes(torrent.InfoHash, 0, 20));
builder.Query = string.Format("{0}&info_hash={1}", query.ToString(), info_hash);
var announceRequest = new WebClient();
announceRequest.Proxy = null;
var result = announceRequest.DownloadData(builder.Uri);
var announceResults = BEncode.DecodeObject(new DataIndex(result));
}
private static void TestPieceHashing(Torrent torrent)
{
// Load the contents of the downloaded file
var dlContents = File.ReadAllBytes(@"insert-sample-downloaded-file-here");
// Compute the hash of the real downloaded file
var sha1 = SHA1.Create();
var sha1Hash = sha1.ComputeHash(dlContents.Take((int) torrent.TorrentInfo.PieceLength).ToArray());
if (sha1Hash.SequenceEqual(torrent.TorrentInfo.Pieces.First()))
{
// If this evaluates to true, the following has been verified:
// - The BEncode decoding worked correctly.
// - The piece length was read in accurately.
// - The pieces list was read in correctly.
// - The SHA1 computation we just computed is the same as the first set of bytes in the pieces section of the torrent file.
System.Console.WriteLine("Success: SHA1 hash of the first piece corresponds to the piece hash found in the torrent file.");
}
else
{
throw new Exception("Failure: SHA1 hash of the first piece did not match the piece hash found in the torrent file.");
}
}
