mirror of
https://github.com/webtorrent/bittorrent-tracker.git
synced 2024-12-13 19:06:27 +00:00
282 lines
7.7 KiB
JavaScript
282 lines
7.7 KiB
JavaScript
// TODO: cleanup unused Peers when tracker doesn't respond with matches
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module.exports = WebSocketTracker
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var debug = require('debug')('bittorrent-tracker:websocket-tracker')
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var EventEmitter = require('events').EventEmitter
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var hat = require('hat')
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var inherits = require('inherits')
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var Peer = require('simple-peer')
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var Socket = require('simple-websocket')
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var common = require('./common')
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// Use a socket pool, so tracker clients share WebSocket objects for the same server.
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// In practice, WebSockets are pretty slow to establish, so this gives a nice performance
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// boost, and saves browser resources.
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var socketPool = {}
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var RECONNECT_VARIANCE = 30 * 1000
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var RECONNECT_MINIMUM = 5 * 1000
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inherits(WebSocketTracker, EventEmitter)
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function WebSocketTracker (client, announceUrl, opts) {
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var self = this
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EventEmitter.call(self)
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debug('new websocket tracker %s', announceUrl)
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self.client = client
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self.destroyed = false
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self._opts = opts
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if (announceUrl[announceUrl.length - 1] === '/') {
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announceUrl = announceUrl.substring(0, announceUrl.length - 1)
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}
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self._announceUrl = announceUrl
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self._peers = {} // peers (offer id -> peer)
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self._socket = null
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self._intervalMs = self.client._intervalMs // use client interval initially
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self._interval = null
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self._openSocket()
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}
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WebSocketTracker.prototype.announce = function (opts) {
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var self = this
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if (self.destroyed) return
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if (!self._socket.connected) {
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return self._socket.once('connect', self.announce.bind(self, opts))
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}
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opts.info_hash = self.client._infoHashBinary
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opts.peer_id = self.client._peerIdBinary
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// Limit number of offers (temporarily)
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// TODO: remove this when we cleanup old RTCPeerConnections cleanly
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if (opts.numWant > 10) opts.numWant = 10
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self._generateOffers(opts.numWant, function (offers) {
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opts.offers = offers
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if (self._trackerId) {
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opts.trackerid = self._trackerId
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}
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self._send(opts)
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})
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}
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WebSocketTracker.prototype.scrape = function (opts) {
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var self = this
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if (self.destroyed) return
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self._onSocketError(new Error('scrape not supported ' + self._announceUrl))
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}
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// TODO: Improve this interface
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WebSocketTracker.prototype.setInterval = function (intervalMs) {
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var self = this
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clearInterval(self._interval)
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self._intervalMs = intervalMs
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if (intervalMs) {
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// HACK
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var update = self.announce.bind(self, self.client._defaultAnnounceOpts())
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self._interval = setInterval(update, self._intervalMs)
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}
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}
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WebSocketTracker.prototype.destroy = function () {
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var self = this
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if (self.destroyed) return
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self.destroyed = true
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self._socket.removeListener('data', self._onSocketDataBound)
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self._socket.removeListener('close', self._onSocketCloseBound)
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self._socket.removeListener('error', self._onSocketErrorBound)
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self._onSocketErrorBound = null
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self._onSocketDataBound = null
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self._onSocketCloseBound = null
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self._socket.on('error', noop) // ignore all future errors
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try { self._socket.close() } catch (e) {}
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self._socket = null
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}
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WebSocketTracker.prototype._openSocket = function () {
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var self = this
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self._onSocketErrorBound = self._onSocketError.bind(self)
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self._onSocketDataBound = self._onSocketData.bind(self)
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self._onSocketCloseBound = self._onSocketClose.bind(self)
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self._socket = socketPool[self._announceUrl]
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if (!self._socket) {
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self._socket = socketPool[self._announceUrl] = new Socket(self._announceUrl)
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}
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self._socket.on('data', self._onSocketDataBound)
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self._socket.on('close', self._onSocketCloseBound)
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self._socket.on('error', self._onSocketErrorBound)
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}
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WebSocketTracker.prototype._onSocketData = function (data) {
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var self = this
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if (self.destroyed) return
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if (!(typeof data === 'object' && data !== null)) {
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return self.client.emit('warning', new Error('Invalid tracker response'))
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}
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if (data.info_hash !== self.client._infoHashBinary) {
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debug(
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'ignoring websocket data from %s for %s (looking for %s: reused socket)',
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self._announceUrl, common.binaryToHex(data.info_hash), self.client._infoHashHex
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)
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return
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}
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if (data.peer_id && data.peer_id === self.client._peerIdBinary) {
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// ignore offers/answers from this client
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return
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}
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debug(
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'received %s from %s for %s',
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JSON.stringify(data), self._announceUrl, self.client._infoHashHex
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)
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var failure = data['failure reason']
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if (failure) return self.client.emit('warning', new Error(failure))
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var warning = data['warning message']
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if (warning) self.client.emit('warning', new Error(warning))
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var interval = data.interval || data['min interval']
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if (interval && !self._opts.interval && self._intervalMs !== 0) {
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// use the interval the tracker recommends, UNLESS the user manually specifies an
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// interval they want to use
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self.setInterval(interval * 1000)
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}
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var trackerId = data['tracker id']
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if (trackerId) {
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// If absent, do not discard previous trackerId value
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self._trackerId = trackerId
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}
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if (data.complete) {
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self.client.emit('update', {
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announce: self._announceUrl,
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complete: data.complete,
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incomplete: data.incomplete
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})
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}
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var peer
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if (data.offer && data.peer_id) {
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peer = new Peer({
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trickle: false,
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config: self.client._rtcConfig,
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wrtc: self.client._wrtc
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})
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peer.id = common.binaryToHex(data.peer_id)
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peer.once('signal', function (answer) {
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var params = {
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info_hash: self.client._infoHashBinary,
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peer_id: self.client._peerIdBinary,
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to_peer_id: data.peer_id,
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answer: answer,
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offer_id: data.offer_id
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}
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if (self._trackerId) params.trackerid = self._trackerId
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self._send(params)
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})
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peer.signal(data.offer)
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self.client.emit('peer', peer)
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}
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if (data.answer && data.peer_id) {
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peer = self._peers[common.binaryToHex(data.offer_id)]
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if (peer) {
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peer.id = common.binaryToHex(data.peer_id)
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peer.signal(data.answer)
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self.client.emit('peer', peer)
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} else {
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debug('got unexpected answer: ' + JSON.stringify(data.answer))
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}
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}
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}
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WebSocketTracker.prototype._onSocketClose = function () {
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var self = this
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if (self.destroyed) return
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self.destroy()
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self._startReconnectTimer()
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}
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WebSocketTracker.prototype._onSocketError = function (err) {
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var self = this
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if (self.destroyed) return
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self.destroy()
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// errors will often happen if a tracker is offline, so don't treat it as fatal
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self.client.emit('warning', err)
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self._startReconnectTimer()
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}
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WebSocketTracker.prototype._startReconnectTimer = function () {
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var self = this
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var ms = Math.floor(Math.random() * RECONNECT_VARIANCE) + RECONNECT_MINIMUM
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setTimeout(function () {
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self.destroyed = false
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self._openSocket()
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}, ms)
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debug('reconnecting socket in %s ms', ms)
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}
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WebSocketTracker.prototype._send = function (params) {
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var self = this
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if (self.destroyed) return
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var message = JSON.stringify(params)
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debug('send %s', message)
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self._socket.send(message)
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}
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WebSocketTracker.prototype._generateOffers = function (numWant, cb) {
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var self = this
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var offers = []
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debug('generating %s offers', numWant)
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// TODO: cleanup dead peers and peers that never get a return offer, from self._peers
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for (var i = 0; i < numWant; ++i) {
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generateOffer()
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}
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function generateOffer () {
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var offerId = hat(160)
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var peer = self._peers[offerId] = new Peer({
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initiator: true,
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trickle: false,
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config: self.client._rtcConfig,
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wrtc: self.client._wrtc
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})
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peer.once('signal', function (offer) {
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offers.push({
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offer: offer,
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offer_id: common.hexToBinary(offerId)
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})
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checkDone()
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})
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}
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function checkDone () {
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if (offers.length === numWant) {
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debug('generated %s offers', numWant)
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cb(offers)
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}
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}
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}
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function noop () {}
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