add support for webtorrent (websocket) trackers

client.js

@@ -7,8 +7,8 @@ var once = require('once')
 var url = require('url')
 
 var common = require('./lib/common')
-var HTTPTracker = require('./lib/http-tracker')
+var HTTPTracker = require('./lib/http-tracker') // empty object in browser
-var UDPTracker = require('./lib/udp-tracker')
+var UDPTracker = require('./lib/udp-tracker') // empty object in browser
 var WebSocketTracker = require('./lib/websocket-tracker')
 
 inherits(Client, EventEmitter)
@@ -47,24 +47,24 @@ function Client (peerId, port, torrent, opts) {
   debug('new client %s', self._infoHash.toString('hex'))
 
   if (typeof torrent.announce === 'string') torrent.announce = [ torrent.announce ]
+  if (torrent.announce == null) torrent.announce = []
 
-  self._trackers = (torrent.announce || [])
+  self._trackers = torrent.announce
-    .filter(function (announceUrl) {
-      var protocol = url.parse(announceUrl).protocol
-      return [ 'udp:', 'http:', 'https:', 'ws:', 'wss:' ].indexOf(protocol) !== -1
-    })
     .map(function (announceUrl) {
       var trackerOpts = { interval: self._intervalMs }
       var protocol = url.parse(announceUrl).protocol
 
-      if (protocol === 'http:' || protocol === 'https:') {
+      if ((protocol === 'http:' || protocol === 'https:') &&
+          typeof HTTPTracker === 'function') {
         return new HTTPTracker(self, announceUrl, trackerOpts)
-      } else if (protocol === 'udp:') {
+      } else if (protocol === 'udp:' && typeof UDPTracker === 'function') {
         return new UDPTracker(self, announceUrl, trackerOpts)
       } else if (protocol === 'ws:' || protocol === 'wss:') {
         return new WebSocketTracker(self, announceUrl, trackerOpts)
       }
+      return null
     })
+    .filter(Boolean)
 }
 
 /**

lib/common-node.js

@@ -0,0 +1,64 @@
+/**
+ * Functions/constants needed by both the client and server (but only in node).
+ * These are separate from common.js so they can be skipped when bundling for the browser.
+ */
+
+var querystring = require('querystring')
+
+exports.IPV4_RE = /^[\d\.]+$/
+exports.IPV6_RE = /^[\da-fA-F:]+$/
+
+exports.CONNECTION_ID = Buffer.concat([ toUInt32(0x417), toUInt32(0x27101980) ])
+exports.ACTIONS = { CONNECT: 0, ANNOUNCE: 1, SCRAPE: 2, ERROR: 3 }
+exports.EVENTS = { update: 0, completed: 1, started: 2, stopped: 3 }
+exports.EVENT_IDS = {
+  0: 'update',
+  1: 'completed',
+  2: 'started',
+  3: 'stopped'
+}
+exports.EVENT_NAMES = {
+  update: 'update',
+  completed: 'complete',
+  started: 'start',
+  stopped: 'stop'
+}
+
+function toUInt32 (n) {
+  var buf = new Buffer(4)
+  buf.writeUInt32BE(n, 0)
+  return buf
+}
+exports.toUInt32 = toUInt32
+
+/**
+ * `querystring.parse` using `unescape` instead of decodeURIComponent, since bittorrent
+ * clients send non-UTF8 querystrings
+ * @param  {string} q
+ * @return {Object}
+ */
+exports.querystringParse = function (q) {
+  var saved = querystring.unescape
+  querystring.unescape = unescape // global
+  var ret = querystring.parse(q)
+  querystring.unescape = saved
+  return ret
+}
+
+/**
+ * `querystring.stringify` using `escape` instead of encodeURIComponent, since bittorrent
+ * clients send non-UTF8 querystrings
+ * @param  {Object} obj
+ * @return {string}
+ */
+exports.querystringStringify = function (obj) {
+  var saved = querystring.escape
+  querystring.escape = escape // global
+  var ret = querystring.stringify(obj)
+  ret = ret.replace(/[\@\*\/\+]/g, function (char) {
+    // `escape` doesn't encode the characters @*/+ so we do it manually
+    return '%' + char.charCodeAt(0).toString(16).toUpperCase()
+  })
+  querystring.escape = saved
+  return ret
+}

lib/common.js

@@ -2,39 +2,13 @@
  * Functions/constants needed by both the client and server.
  */
 
-var querystring = require('querystring')
+var extend = require('xtend/mutable')
-
-exports.IPV4_RE = /^[\d\.]+$/
-exports.IPV6_RE = /^[\da-fA-F:]+$/
 
 exports.DEFAULT_ANNOUNCE_INTERVAL = 30 * 60 * 1000 // 30 minutes
 
 exports.DEFAULT_ANNOUNCE_PEERS = 50
 exports.MAX_ANNOUNCE_PEERS = 82
 
-exports.CONNECTION_ID = Buffer.concat([ toUInt32(0x417), toUInt32(0x27101980) ])
-exports.ACTIONS = { CONNECT: 0, ANNOUNCE: 1, SCRAPE: 2, ERROR: 3 }
-exports.EVENTS = { update: 0, completed: 1, started: 2, stopped: 3 }
-exports.EVENT_IDS = {
-  0: 'update',
-  1: 'completed',
-  2: 'started',
-  3: 'stopped'
-}
-exports.EVENT_NAMES = {
-  update: 'update',
-  completed: 'complete',
-  started: 'start',
-  stopped: 'stop'
-}
-
-function toUInt32 (n) {
-  var buf = new Buffer(4)
-  buf.writeUInt32BE(n, 0)
-  return buf
-}
-exports.toUInt32 = toUInt32
-
 exports.binaryToHex = function (str) {
   return new Buffer(str, 'binary').toString('hex')
 }
@@ -43,34 +17,5 @@ exports.hexToBinary = function (str) {
   return new Buffer(str, 'hex').toString('binary')
 }
 
-/**
+var config = require('./common-node')
- * `querystring.parse` using `unescape` instead of decodeURIComponent, since bittorrent
+extend(exports, config)
- * clients send non-UTF8 querystrings
- * @param  {string} q
- * @return {Object}
- */
-exports.querystringParse = function (q) {
-  var saved = querystring.unescape
-  querystring.unescape = unescape // global
-  var ret = querystring.parse(q)
-  querystring.unescape = saved
-  return ret
-}
-
-/**
- * `querystring.stringify` using `escape` instead of encodeURIComponent, since bittorrent
- * clients send non-UTF8 querystrings
- * @param  {Object} obj
- * @return {string}
- */
-exports.querystringStringify = function (obj) {
-  var saved = querystring.escape
-  querystring.escape = escape // global
-  var ret = querystring.stringify(obj)
-  ret = ret.replace(/[\@\*\/\+]/g, function (char) {
-    // `escape` doesn't encode the characters @*/+ so we do it manually
-    return '%' + char.charCodeAt(0).toString(16).toUpperCase()
-  })
-  querystring.escape = saved
-  return ret
-}

lib/http-tracker.js

@@ -88,8 +88,14 @@ HTTPTracker.prototype._request = function (requestUrl, opts, cb) {
 
   get.concat(u, function (err, data, res) {
     if (err) return self.client.emit('warning', err)
-    if (res.statusCode !== 200) return self.client.emit('warning', new Error('Non-200 response code ' + res.statusCode + ' from ' + self.a))
+    if (res.statusCode !== 200) {
-    if (!data || data.length === 0) return
+      return self.client.emit('warning', new Error('Non-200 response code ' +
+        res.statusCode + ' from ' + self._announceUrl))
+    }
+    if (!data || data.length === 0) {
+      return self.client.emit('warning', new Error('Invalid tracker response from' +
+        self._announceUrl))
+    }
 
     try {
       data = bencode.decode(data)

lib/websocket-tracker.js

@@ -0,0 +1,189 @@
+// TODO: destroy the websocket
+
+module.exports = WebSocketTracker
+
+var debug = require('debug')('bittorrent-tracker:http-tracker')
+var EventEmitter = require('events').EventEmitter
+var hat = require('hat')
+var inherits = require('inherits')
+var Peer = require('simple-peer')
+var Socket = require('simple-websocket')
+
+var common = require('./common')
+
+// It turns out that you can't open multiple websockets to the same server within one
+// browser tab, so let's reuse them.
+var socketPool = {}
+
+inherits(WebSocketTracker, EventEmitter)
+
+function WebSocketTracker (client, announceUrl, opts) {
+  var self = this
+  EventEmitter.call(self)
+  debug('new websocket tracker %s', announceUrl)
+
+  self.client = client
+
+  self._announceUrl = announceUrl
+  self._peers = {} // peers (offer id -> peer)
+  self._ready = false
+  self._socket = null
+  self._intervalMs = self.client._intervalMs // use client interval initially
+  self._interval = null
+
+  if (socketPool[announceUrl]) self._socket = socketPool[announceUrl]
+  else self._socket = socketPool[announceUrl] = new Socket(announceUrl)
+
+  self._socket.on('warning', self._onSocketWarning.bind(self))
+  self._socket.on('error', self._onSocketWarning.bind(self)) // TODO: handle error
+  self._socket.on('message', self._onSocketMessage.bind(self))
+}
+
+WebSocketTracker.prototype.announce = function (opts) {
+  var self = this
+  if (!self._socket.ready) return self._socket.on('ready', self.announce.bind(self, opts))
+
+  opts.info_hash = self.client._infoHash.toString('binary')
+  opts.peer_id = self.client._peerId.toString('binary')
+
+  self._generateOffers(opts.numWant, function (offers) {
+    opts.offers = offers
+
+    if (self._trackerId) {
+      opts.trackerid = self._trackerId
+    }
+    self._send(opts)
+  })
+}
+
+WebSocketTracker.prototype.scrape = function (opts) {
+  var self = this
+  self.client.emit('error', new Error('scrape not supported ' + self._announceUrl))
+  return
+}
+
+// TODO: Improve this interface
+WebSocketTracker.prototype.setInterval = function (intervalMs) {
+  var self = this
+  clearInterval(self._interval)
+
+  self._intervalMs = intervalMs
+  if (intervalMs) {
+    // HACK
+    var update = self.announce.bind(self, self.client._defaultAnnounceOpts())
+    self._interval = setInterval(update, self._intervalMs)
+  }
+}
+
+WebSocketTracker.prototype._onSocketWarning = function (err) {
+  debug('tracker warning %s', err.message)
+}
+
+WebSocketTracker.prototype._onSocketMessage = function (data) {
+  var self = this
+
+  if (!(typeof data === 'object' && data !== null)) {
+    return self.client.emit('warning', new Error('Invalid tracker response'))
+  }
+
+  if (data.info_hash !== self.client._infoHash.toString('binary')) return
+
+  debug('received %s from %s', JSON.stringify(data), self._announceUrl)
+
+  var failure = data['failure reason']
+  if (failure) return self.client.emit('warning', new Error(failure))
+
+  var warning = data['warning message']
+  if (warning) self.client.emit('warning', new Error(warning))
+
+  var interval = data.interval || data['min interval']
+  if (interval && !self._opts.interval && self._intervalMs !== 0) {
+    // use the interval the tracker recommends, UNLESS the user manually specifies an
+    // interval they want to use
+    self.setInterval(interval * 1000)
+  }
+
+  var trackerId = data['tracker id']
+  if (trackerId) {
+    // If absent, do not discard previous trackerId value
+    self._trackerId = trackerId
+  }
+
+  if (data.complete) {
+    self.client.emit('update', {
+      announce: self._announceUrl,
+      complete: data.complete,
+      incomplete: data.incomplete
+    })
+  }
+
+  var peer
+  if (data.offer) {
+    peer = new Peer({ trickle: false, config: self._opts.rtcConfig })
+    peer.id = common.binaryToHex(data.peer_id)
+    peer.once('signal', function (answer) {
+      var opts = {
+        info_hash: self.client._infoHash.toString('binary'),
+        peer_id: self.client._peerId.toString('binary'),
+        to_peer_id: data.peer_id,
+        answer: answer,
+        offer_id: data.offer_id
+      }
+      if (self._trackerId) opts.trackerid = self._trackerId
+      self._send(opts)
+    })
+    peer.signal(data.offer)
+    self.client.emit('peer', peer)
+  }
+
+  if (data.answer) {
+    peer = self._peers[data.offer_id]
+    if (peer) {
+      peer.id = common.binaryToHex(data.peer_id)
+      peer.signal(data.answer)
+      self.client.emit('peer', peer)
+    } else {
+      debug('got unexpected answer: ' + JSON.stringify(data.answer))
+    }
+  }
+}
+
+WebSocketTracker.prototype._send = function (opts) {
+  var self = this
+  debug('send %s', JSON.stringify(opts))
+  self._socket.send(opts)
+}
+
+WebSocketTracker.prototype._generateOffers = function (numWant, cb) {
+  var self = this
+  var offers = []
+  debug('generating %s offers', numWant)
+
+  // TODO: cleanup dead peers and peers that never get a return offer, from self._peers
+  for (var i = 0; i < numWant; ++i) {
+    generateOffer()
+  }
+
+  function generateOffer () {
+    var offerId = hat(160)
+    var peer = self._peers[offerId] = new Peer({
+      initiator: true,
+      trickle: false,
+      config: self._opts.rtcConfig
+    })
+    peer.once('signal', function (offer) {
+      offers.push({
+        offer: offer,
+        offer_id: offerId
+      })
+      checkDone()
+    })
+  }
+
+  function checkDone () {
+    if (offers.length === numWant) {
+      debug('generated %s offers', numWant)
+      cb(offers)
+    }
+  }
+}

package.json

@@ -7,12 +7,15 @@
     "email": "feross@feross.org",
     "url": "http://feross.org/"
   },
-  "browser": {
-    "./server.js": false
-  },
   "bin": {
     "bittorrent-tracker": "./bin/cmd.js"
   },
+  "browser": {
+    "./lib/common-node": false,
+    "./lib/http-tracker": false,
+    "./lib/udp-tracker": false,
+    "./server": false
+  },
   "bugs": {
     "url": "https://github.com/feross/bittorrent-tracker/issues"
   },
@@ -29,7 +32,10 @@
     "once": "^1.3.0",
     "run-series": "^1.0.2",
     "simple-get": "^1.3.0",
-    "string2compact": "^1.1.1"
+    "simple-peer": "4.0.4",
+    "simple-websocket": "1.0.4",
+    "string2compact": "^1.1.1",
+    "xtend": "4.0.0"
   },
   "devDependencies": {
     "magnet-uri": "^4.0.0",