bittorrent-tracker

Simple, robust, BitTorrent tracker (client & server) implementation

Node.js implementation of a BitTorrent tracker, client and server.

A BitTorrent tracker is an web service which responds to requests from BitTorrent clients. The requests include metrics from clients that help the tracker keep overall statistics about the torrent. The response includes a peer list that helps the client participate in the torrent swarm.

This module is used by WebTorrent.

features

• Includes client & server implementations
• Supports all mainstream tracker types:
  • HTTP trackers
  • UDP trackers (BEP 15)
  • WebTorrent trackers (BEP forthcoming)
• Supports ipv4 & ipv6
• Supports tracker "scrape" extension
• Robust and well-tested
  • Comprehensive test suite (runs entirely offline, so it's reliable)
  • Used by popular clients: WebTorrent, peerflix, and playback

Also see bittorrent-dht.

install

npm install bittorrent-tracker

usage

client

To connect to a tracker, just do this:

var Client = require('bittorrent-tracker')
var parseTorrent = require('parse-torrent')
var fs = require('fs')

var torrent = fs.readFileSync(__dirname + '/torrents/bitlove-intro.torrent')
var parsedTorrent = parseTorrent(torrent) // { infoHash: 'xxx', length: xx, announce: ['xx', 'xx'] }

var peerId = new Buffer('01234567890123456789')
var port = 6881

// optional options dictionary
var opts = {
  // RTCPeerConnection config object (only used in browser)
  rtcConfig: {},
  // custom webrtc impl, useful in node to specify [wrtc](https://npmjs.com/package/wrtc)
  wrtc: {},
  getAnnounceOpts: function () {
    // provide a callback that will be called whenever announce() is called
    // internally (on timer), or by the user
    return {
      uploaded: 0,
      downloaded: 0,
      left: 0,
      customParam: 'blah' // custom parameters supported
    }
  }
}

var client = new Client(peerId, port, parsedTorrent)

client.on('error', function (err) {
  // fatal client error!
  console.log(err.message)
})

client.on('warning', function (err) {
  // a tracker was unavailable or sent bad data to the client. you can probably ignore it
  console.log(err.message)
})

// start getting peers from the tracker
client.start()

client.on('update', function (data) {
  console.log('got an announce response from tracker: ' + data.announce)
  console.log('number of seeders in the swarm: ' + data.complete)
  console.log('number of leechers in the swarm: ' + data.incomplete)
})

client.once('peer', function (addr) {
  console.log('found a peer: ' + addr) // 85.10.239.191:48623
})

// announce that download has completed (and you are now a seeder)
client.complete()

// force a tracker announce. will trigger more 'update' events and maybe more 'peer' events
client.update()

// provide parameters to the tracker
client.update({
  uploaded: 0,
  downloaded: 0,
  left: 0,
  customParam: 'blah' // custom parameters supported
})

// stop getting peers from the tracker, gracefully leave the swarm
client.stop()

// ungracefully leave the swarm (without sending final 'stop' message)
client.destroy()

// scrape
client.scrape()

client.on('scrape', function (data) {
  console.log('got a scrape response from tracker: ' + data.announce)
  console.log('number of seeders in the swarm: ' + data.complete)
  console.log('number of leechers in the swarm: ' + data.incomplete)
  console.log('number of total downloads of this torrent: ' + data.downloaded)
})

server

To start a BitTorrent tracker server to track swarms of peers:

var Server = require('bittorrent-tracker').Server

var server = new Server({
  udp: true, // enable udp server? [default=true]
  http: true, // enable http server? [default=true]
  ws: true, // enable websocket server? [default=true]
  filter: function (infoHash, params, cb) {
    // Blacklist/whitelist function for allowing/disallowing torrents. If this option is
    // omitted, all torrents are allowed. It is possible to interface with a database or
    // external system before deciding to allow/deny, because this function is async.

    // It is possible to block by peer id (whitelisting torrent clients) or by secret
    // key (private trackers). Full access to the original HTTP/UDP request parameters
    // are available in `params`.

    // This example only allows one torrent.

    var allowed = (infoHash === 'aaa67059ed6bd08362da625b3ae77f6f4a075aaa')
    cb(allowed)

    // In addition to returning a boolean (`true` for allowed, `false` for disallowed),
    // you can return an `Error` object to disallow and provide a custom reason.
  }
})

// Internal http, udp, and websocket servers exposed as public properties.
server.http
server.udp
server.ws

server.on('error', function (err) {
  // fatal server error!
  console.log(err.message)
})

server.on('warning', function (err) {
  // client sent bad data. probably not a problem, just a buggy client.
  console.log(err.message)
})

server.on('listening', function () {
  // fired when all requested servers are listening
  console.log('listening on http port:' + server.http.address().port)
  console.log('listening on udp port:' + server.udp.address().port)
})

// start tracker server listening! Use 0 to listen on a random free port.
server.listen(port, hostname, onlistening)

// listen for individual tracker messages from peers:

server.on('start', function (addr) {
  console.log('got start message from ' + addr)
})

server.on('complete', function (addr) {})
server.on('update', function (addr) {})
server.on('stop', function (addr) {})

// get info hashes for all torrents in the tracker server
Object.keys(server.torrents)

// get the number of seeders for a particular torrent
server.torrents[infoHash].complete

// get the number of leechers for a particular torrent
server.torrents[infoHash].incomplete

// get the peers who are in a particular torrent swarm
server.torrents[infoHash].peers

The http server will handle requests for the following paths: /announce, /scrape. Requests for other paths will not be handled.

multi scrape

Scraping multiple torrent info is possible with a static Client.scrape method:

var Client = require('bittorrent-tracker')
Client.scrape(announceUrl, [ infoHash1, infoHash2 ], function (err, results) {
  results[infoHash1].announce
  results[infoHash1].infoHash
  results[infoHash1].complete
  results[infoHash1].incomplete
  results[infoHash1].downloaded

  // ...
})

command line

Easily start a tracker server:

$ bittorrent-tracker
http server listening on 8000
udp server listening on 8000
ws server listening on 8000

Lots of options:

$ bittorrent-tracker --help
  bittorrent-tracker - Start a bittorrent tracker server

  Usage:
    bittorrent-tracker [OPTIONS]

  If no --http, --udp, or --ws option is supplied, all tracker types will be started.

  Options:
    -p, --port [number]  change the port [default: 8000]
        --trust-proxy    trust 'x-forwarded-for' header from reverse proxy
        --interval       client announce interval (ms) [default: 600000]
        --http           enable http server
        --udp            enable udp server
        --ws             enable websocket server
    -q, --quiet          only show error output
    -s, --silent         show no output
    -v, --version        print the current version

  Please report bugs!  https://github.com/feross/bittorrent-tracker/issues

license

MIT. Copyright (c) Feross Aboukhadijeh.