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| 1 | +// TODO: destroy the websocket |
| 2 | + |
| 3 | +module.exports = WebSocketTracker |
| 4 | + |
| 5 | +var debug = require('debug')('bittorrent-tracker:http-tracker') |
| 6 | +var EventEmitter = require('events').EventEmitter |
| 7 | +var hat = require('hat') |
| 8 | +var inherits = require('inherits') |
| 9 | +var Peer = require('simple-peer') |
| 10 | +var Socket = require('simple-websocket') |
| 11 | + |
| 12 | +var common = require('./common') |
| 13 | + |
| 14 | +// It turns out that you can't open multiple websockets to the same server within one |
| 15 | +// browser tab, so let's reuse them. |
| 16 | +var socketPool = {} |
| 17 | + |
| 18 | +inherits(WebSocketTracker, EventEmitter) |
| 19 | + |
| 20 | +function WebSocketTracker (client, announceUrl, opts) { |
| 21 | + var self = this |
| 22 | + EventEmitter.call(self) |
| 23 | + debug('new websocket tracker %s', announceUrl) |
| 24 | + |
| 25 | + self.client = client |
| 26 | + |
| 27 | + self._announceUrl = announceUrl |
| 28 | + self._peers = {} // peers (offer id -> peer) |
| 29 | + self._ready = false |
| 30 | + self._socket = null |
| 31 | + self._intervalMs = self.client._intervalMs // use client interval initially |
| 32 | + self._interval = null |
| 33 | + |
| 34 | + if (socketPool[announceUrl]) self._socket = socketPool[announceUrl] |
| 35 | + else self._socket = socketPool[announceUrl] = new Socket(announceUrl) |
| 36 | + |
| 37 | + self._socket.on('warning', self._onSocketWarning.bind(self)) |
| 38 | + self._socket.on('error', self._onSocketWarning.bind(self)) // TODO: handle error |
| 39 | + self._socket.on('message', self._onSocketMessage.bind(self)) |
| 40 | +} |
| 41 | + |
| 42 | +WebSocketTracker.prototype.announce = function (opts) { |
| 43 | + var self = this |
| 44 | + if (!self._socket.ready) return self._socket.on('ready', self.announce.bind(self, opts)) |
| 45 | + |
| 46 | + opts.info_hash = self.client._infoHash.toString('binary') |
| 47 | + opts.peer_id = self.client._peerId.toString('binary') |
| 48 | + |
| 49 | + self._generateOffers(opts.numWant, function (offers) { |
| 50 | + opts.offers = offers |
| 51 | + |
| 52 | + if (self._trackerId) { |
| 53 | + opts.trackerid = self._trackerId |
| 54 | + } |
| 55 | + self._send(opts) |
| 56 | + }) |
| 57 | +} |
| 58 | + |
| 59 | +WebSocketTracker.prototype.scrape = function (opts) { |
| 60 | + var self = this |
| 61 | + self.client.emit('error', new Error('scrape not supported ' + self._announceUrl)) |
| 62 | + return |
| 63 | +} |
| 64 | + |
| 65 | +// TODO: Improve this interface |
| 66 | +WebSocketTracker.prototype.setInterval = function (intervalMs) { |
| 67 | + var self = this |
| 68 | + clearInterval(self._interval) |
| 69 | + |
| 70 | + self._intervalMs = intervalMs |
| 71 | + if (intervalMs) { |
| 72 | + // HACK |
| 73 | + var update = self.announce.bind(self, self.client._defaultAnnounceOpts()) |
| 74 | + self._interval = setInterval(update, self._intervalMs) |
| 75 | + } |
| 76 | +} |
| 77 | + |
| 78 | +WebSocketTracker.prototype._onSocketWarning = function (err) { |
| 79 | + debug('tracker warning %s', err.message) |
| 80 | +} |
| 81 | + |
| 82 | +WebSocketTracker.prototype._onSocketMessage = function (data) { |
| 83 | + var self = this |
| 84 | + |
| 85 | + if (!(typeof data === 'object' && data !== null)) { |
| 86 | + return self.client.emit('warning', new Error('Invalid tracker response')) |
| 87 | + } |
| 88 | + |
| 89 | + if (data.info_hash !== self.client._infoHash.toString('binary')) return |
| 90 | + |
| 91 | + debug('received %s from %s', JSON.stringify(data), self._announceUrl) |
| 92 | + |
| 93 | + var failure = data['failure reason'] |
| 94 | + if (failure) return self.client.emit('warning', new Error(failure)) |
| 95 | + |
| 96 | + var warning = data['warning message'] |
| 97 | + if (warning) self.client.emit('warning', new Error(warning)) |
| 98 | + |
| 99 | + var interval = data.interval || data['min interval'] |
| 100 | + if (interval && !self._opts.interval && self._intervalMs !== 0) { |
| 101 | + // use the interval the tracker recommends, UNLESS the user manually specifies an |
| 102 | + // interval they want to use |
| 103 | + self.setInterval(interval * 1000) |
| 104 | + } |
| 105 | + |
| 106 | + var trackerId = data['tracker id'] |
| 107 | + if (trackerId) { |
| 108 | + // If absent, do not discard previous trackerId value |
| 109 | + self._trackerId = trackerId |
| 110 | + } |
| 111 | + |
| 112 | + if (data.complete) { |
| 113 | + self.client.emit('update', { |
| 114 | + announce: self._announceUrl, |
| 115 | + complete: data.complete, |
| 116 | + incomplete: data.incomplete |
| 117 | + }) |
| 118 | + } |
| 119 | + |
| 120 | + var peer |
| 121 | + if (data.offer) { |
| 122 | + peer = new Peer({ trickle: false, config: self._opts.rtcConfig }) |
| 123 | + peer.id = common.binaryToHex(data.peer_id) |
| 124 | + peer.once('signal', function (answer) { |
| 125 | + var opts = { |
| 126 | + info_hash: self.client._infoHash.toString('binary'), |
| 127 | + peer_id: self.client._peerId.toString('binary'), |
| 128 | + to_peer_id: data.peer_id, |
| 129 | + answer: answer, |
| 130 | + offer_id: data.offer_id |
| 131 | + } |
| 132 | + if (self._trackerId) opts.trackerid = self._trackerId |
| 133 | + self._send(opts) |
| 134 | + }) |
| 135 | + peer.signal(data.offer) |
| 136 | + self.client.emit('peer', peer) |
| 137 | + } |
| 138 | + |
| 139 | + if (data.answer) { |
| 140 | + peer = self._peers[data.offer_id] |
| 141 | + if (peer) { |
| 142 | + peer.id = common.binaryToHex(data.peer_id) |
| 143 | + peer.signal(data.answer) |
| 144 | + self.client.emit('peer', peer) |
| 145 | + } else { |
| 146 | + debug('got unexpected answer: ' + JSON.stringify(data.answer)) |
| 147 | + } |
| 148 | + } |
| 149 | +} |
| 150 | + |
| 151 | +WebSocketTracker.prototype._send = function (opts) { |
| 152 | + var self = this |
| 153 | + debug('send %s', JSON.stringify(opts)) |
| 154 | + self._socket.send(opts) |
| 155 | +} |
| 156 | + |
| 157 | +WebSocketTracker.prototype._generateOffers = function (numWant, cb) { |
| 158 | + var self = this |
| 159 | + var offers = [] |
| 160 | + debug('generating %s offers', numWant) |
| 161 | + |
| 162 | + // TODO: cleanup dead peers and peers that never get a return offer, from self._peers |
| 163 | + for (var i = 0; i < numWant; ++i) { |
| 164 | + generateOffer() |
| 165 | + } |
| 166 | + |
| 167 | + function generateOffer () { |
| 168 | + var offerId = hat(160) |
| 169 | + var peer = self._peers[offerId] = new Peer({ |
| 170 | + initiator: true, |
| 171 | + trickle: false, |
| 172 | + config: self._opts.rtcConfig |
| 173 | + }) |
| 174 | + peer.once('signal', function (offer) { |
| 175 | + offers.push({ |
| 176 | + offer: offer, |
| 177 | + offer_id: offerId |
| 178 | + }) |
| 179 | + checkDone() |
| 180 | + }) |
| 181 | + } |
| 182 | + |
| 183 | + function checkDone () { |
| 184 | + if (offers.length === numWant) { |
| 185 | + debug('generated %s offers', numWant) |
| 186 | + cb(offers) |
| 187 | + } |
| 188 | + } |
| 189 | +} |
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