mirror of
https://github.com/webtorrent/bittorrent-tracker.git
synced 2024-12-13 10:56:25 +00:00
506 lines
13 KiB
JavaScript
506 lines
13 KiB
JavaScript
module.exports = Client
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var BN = require('bn.js')
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var bencode = require('bencode')
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var common = require('./lib/common')
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var compact2string = require('compact2string')
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var concat = require('concat-stream')
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var debug = require('debug')('bittorrent-tracker:client')
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var dgram = require('dgram')
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var EventEmitter = require('events').EventEmitter
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var extend = require('extend.js')
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var hat = require('hat')
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var http = require('http')
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var inherits = require('inherits')
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var querystring = require('querystring')
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var url = require('url')
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inherits(Client, EventEmitter)
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/**
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* A Client manages tracker connections for a torrent.
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*
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* @param {string} peerId this peer's id
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* @param {Number} port port number that the client is listening on
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* @param {Object} torrent parsed torrent
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* @param {Object} opts optional options
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* @param {Number} opts.numWant number of peers to request
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* @param {Number} opts.interval interval in ms to send announce requests to the tracker
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*/
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function Client (peerId, port, torrent, opts) {
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var self = this
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if (!(self instanceof Client)) return new Client(peerId, port, torrent, opts)
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EventEmitter.call(self)
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self._opts = opts || {}
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// required
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self._peerId = Buffer.isBuffer(peerId)
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? peerId
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: new Buffer(peerId, 'utf8')
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self._port = port
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self._infoHash = Buffer.isBuffer(torrent.infoHash)
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? torrent.infoHash
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: new Buffer(torrent.infoHash, 'hex')
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self.torrentLength = torrent.length
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// optional
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self._numWant = self._opts.numWant || 80
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self._intervalMs = self._opts.interval || (30 * 60 * 1000) // default: 30 minutes
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debug('new tracker client for ' + self._infoHash.toString('hex'))
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if (typeof torrent.announce === 'string') {
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// magnet-uri returns a string if the magnet uri only contains one 'tr' parameter
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torrent.announce = [torrent.announce]
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}
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self._trackers = torrent.announce.map(function (announceUrl) {
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return new Tracker(self, announceUrl, self._opts)
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})
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}
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Client.prototype.start = function (opts) {
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var self = this
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self._trackers.forEach(function (tracker) {
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tracker.start(opts)
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})
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}
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Client.prototype.stop = function (opts) {
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var self = this
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self._trackers.forEach(function (tracker) {
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tracker.stop(opts)
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})
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}
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Client.prototype.complete = function (opts) {
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var self = this
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self._trackers.forEach(function (tracker) {
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tracker.complete(opts)
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})
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}
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Client.prototype.update = function (opts) {
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var self = this
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self._trackers.forEach(function (tracker) {
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tracker.update(opts)
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})
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}
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Client.prototype.scrape = function (opts) {
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var self = this
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self._trackers.forEach(function (tracker) {
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tracker.scrape(opts)
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})
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}
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Client.prototype.setInterval = function (intervalMs) {
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var self = this
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self._intervalMs = intervalMs
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self._trackers.forEach(function (tracker) {
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tracker.setInterval(intervalMs)
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})
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}
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inherits(Tracker, EventEmitter)
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/**
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* An individual torrent tracker (used by Client)
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*
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* @param {Client} client parent bittorrent tracker client
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* @param {string} announceUrl announce url of tracker
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* @param {Object} opts optional options
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*/
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function Tracker (client, announceUrl, opts) {
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var self = this
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EventEmitter.call(self)
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self._opts = opts || {}
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self.client = client
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debug('new tracker for ' + announceUrl)
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self._announceUrl = announceUrl
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self._intervalMs = self.client._intervalMs // use client interval initially
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self._interval = null
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if (self._announceUrl.indexOf('udp:') === 0) {
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self._requestImpl = self._requestUdp
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} else {
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self._requestImpl = self._requestHttp
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}
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}
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Tracker.prototype.start = function (opts) {
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var self = this
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opts = opts || {}
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opts.event = 'started'
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debug('sent `start` to ' + self._announceUrl)
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self._request(opts)
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self.setInterval(self._intervalMs) // start announcing on intervals
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}
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Tracker.prototype.stop = function (opts) {
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var self = this
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opts = opts || {}
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opts.event = 'stopped'
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debug('sent `stop` to ' + self._announceUrl)
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self._request(opts)
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self.setInterval(0) // stop announcing on intervals
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}
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Tracker.prototype.complete = function (opts) {
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var self = this
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opts = opts || {}
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opts.event = 'completed'
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opts.downloaded = opts.downloaded || self.torrentLength || 0
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debug('sent `complete` to ' + self._announceUrl)
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self._request(opts)
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}
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Tracker.prototype.update = function (opts) {
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var self = this
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opts = opts || {}
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debug('sent `update` to ' + self._announceUrl)
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self._request(opts)
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}
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Tracker.prototype.scrape = function (opts) {
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var self = this
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if (!self._scrapeUrl) {
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var announce = 'announce'
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var i = self._announceUrl.lastIndexOf('/') + 1
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if (i >= 1 && self._announceUrl.slice(i, i + announce.length) === announce) {
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self._scrapeUrl = self._announceUrl.slice(0, i) + 'scrape' + self._announceUrl.slice(i + announce.length)
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}
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}
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if (!self._scrapeUrl) {
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debug('scrape not supported by ' + self._announceUrl)
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self.client.emit('error', new Error('scrape not supported for announceUrl ' + self._announceUrl))
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return
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}
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debug('sent `scrape` to ' + self._announceUrl)
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opts = extend({
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info_hash: bytewiseEncodeURIComponent(self.client._infoHash)
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}, opts)
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self._requestImpl(self._scrapeUrl, opts)
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}
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Tracker.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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self._interval = setInterval(self.update.bind(self), self._intervalMs)
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}
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}
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/**
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* Send an announce request to the tracker
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*/
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Tracker.prototype._request = function (opts) {
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var self = this
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opts = extend({
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info_hash: bytewiseEncodeURIComponent(self.client._infoHash),
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peer_id: bytewiseEncodeURIComponent(self.client._peerId),
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port: self.client._port,
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compact: 1,
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numwant: self.client._numWant,
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uploaded: 0, // default, user should provide real value
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downloaded: 0 // default, user should provide real value
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}, opts)
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if (self.client.torrentLength !== undefined) {
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opts.left = self.client.torrentLength - (opts.downloaded || 0)
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}
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if (self._trackerId) {
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opts.trackerid = self._trackerId
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}
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self._requestImpl(self._announceUrl, opts)
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}
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Tracker.prototype._requestHttp = function (requestUrl, opts) {
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var self = this
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var fullUrl = requestUrl + '?' + querystring.stringify(opts)
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var req = http.get(fullUrl, function (res) {
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if (res.statusCode !== 200) {
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res.resume() // consume the whole stream
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self.client.emit('error', new Error('Invalid response code ' + res.statusCode + ' from tracker ' + requestUrl))
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return
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}
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res.pipe(concat(function (data) {
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if (data && data.length) self._handleResponse(requestUrl, data)
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}))
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})
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req.on('error', function (err) {
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self.client.emit('error', err)
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})
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}
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Tracker.prototype._requestUdp = function (requestUrl, opts) {
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var self = this
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var parsedUrl = url.parse(requestUrl)
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var socket = dgram.createSocket('udp4')
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var transactionId = new Buffer(hat(32), 'hex')
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var stopped = opts.event === 'stopped'
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// if we're sending a stopped message, we don't really care if it arrives, so set
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// a short timer and don't call error
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var timeout = setTimeout(function () {
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timeout = null
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cleanup()
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if (!stopped) {
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error('tracker request timed out')
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}
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}, stopped ? 1500 : 15000)
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if (timeout && timeout.unref) {
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timeout.unref()
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}
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send(Buffer.concat([
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common.CONNECTION_ID,
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common.toUInt32(common.ACTIONS.CONNECT),
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transactionId
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]))
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socket.on('error', error)
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socket.on('message', function (msg, rinfo) {
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if (msg.length < 8 || msg.readUInt32BE(4) !== transactionId.readUInt32BE(0)) {
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return error('tracker sent back invalid transaction id')
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}
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var action = msg.readUInt32BE(0)
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switch (action) {
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case 0: // handshake
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if (msg.length < 16) {
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return error('invalid udp handshake')
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}
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var scrapeStr = 'scrape'
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if (requestUrl.substr(requestUrl.lastIndexOf('/') + 1, scrapeStr.length) === scrapeStr) {
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scrape(msg.slice(8, 16), opts)
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} else {
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announce(msg.slice(8, 16), opts)
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}
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return
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case 1: // announce
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cleanup()
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if (msg.length < 20) {
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return error('invalid announce message')
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}
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var interval = msg.readUInt32BE(8)
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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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self.client.emit('update', {
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announce: self._announceUrl,
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complete: msg.readUInt32BE(16),
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incomplete: msg.readUInt32BE(12)
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})
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compact2string.multi(msg.slice(20)).forEach(function (addr) {
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self.client.emit('peer', addr)
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})
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break
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case 2: // scrape
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cleanup()
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if (msg.length < 20) {
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return error('invalid scrape message')
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}
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self.client.emit('scrape', {
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announce: self._announceUrl,
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complete: msg.readUInt32BE(8),
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downloaded: msg.readUInt32BE(12),
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incomplete: msg.readUInt32BE(16)
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})
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break
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case 3: // error
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cleanup()
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if (msg.length < 8) {
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return error('invalid error message')
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}
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self.client.emit('error', new Error(msg.slice(8).toString()))
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break
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}
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})
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function send (message) {
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if (!parsedUrl.port) {
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parsedUrl.port = 80
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}
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socket.send(message, 0, message.length, parsedUrl.port, parsedUrl.hostname)
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}
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function error (message) {
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self.client.emit('error', new Error(message + ' (connecting to tracker ' + requestUrl + ')'))
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cleanup()
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}
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function cleanup () {
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if (timeout) {
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clearTimeout(timeout)
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timeout = null
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}
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try { socket.close() } catch (err) {}
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}
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function genTransactionId () {
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transactionId = new Buffer(hat(32), 'hex')
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}
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function announce (connectionId, opts) {
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opts = opts || {}
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genTransactionId()
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send(Buffer.concat([
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connectionId,
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common.toUInt32(common.ACTIONS.ANNOUNCE),
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transactionId,
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self.client._infoHash,
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self.client._peerId,
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toUInt64(opts.downloaded || 0),
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opts.left ? toUInt64(opts.left) : new Buffer('FFFFFFFFFFFFFFFF', 'hex'),
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toUInt64(opts.uploaded || 0),
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common.toUInt32(common.EVENTS[opts.event] || 0),
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common.toUInt32(0), // ip address (optional)
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common.toUInt32(0), // key (optional)
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common.toUInt32(self.client._numWant),
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toUInt16(self.client._port || 0)
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]))
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}
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function scrape (connectionId, opts) {
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genTransactionId()
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send(Buffer.concat([
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connectionId,
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common.toUInt32(common.ACTIONS.SCRAPE),
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transactionId,
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self.client._infoHash
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]))
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}
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}
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Tracker.prototype._handleResponse = function (requestUrl, data) {
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var self = this
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try {
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data = bencode.decode(data)
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} catch (err) {
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return self.client.emit('error', new Error('Error decoding tracker response: ' + err.message))
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}
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var failure = data['failure reason']
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if (failure) {
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return self.client.emit('error', new Error(failure))
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}
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var warning = data['warning message']
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if (warning) {
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self.client.emit('warning', warning)
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}
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if (requestUrl === self._announceUrl) {
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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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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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if (Buffer.isBuffer(data.peers)) {
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// tracker returned compact response
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compact2string.multi(data.peers).forEach(function (addr) {
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self.client.emit('peer', addr)
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})
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} else if (Array.isArray(data.peers)) {
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// tracker returned normal response
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data.peers.forEach(function (peer) {
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var ip = peer.ip
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self.client.emit('peer', ip[0] + '.' + ip[1] + '.' + ip[2] + '.' + ip[3] + ':' + peer.port)
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})
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}
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} else if (requestUrl === self._scrapeUrl) {
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// NOTE: the unofficial spec says to use the 'files' key but i've seen 'host' in practice
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data = data.files || data.host || {}
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data = data[bytewiseEncodeURIComponent(self.client._infoHash)]
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if (!data) {
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self.client.emit('error', new Error('invalid scrape response'))
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} else {
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// TODO: optionally handle data.flags.min_request_interval (separate from announce interval)
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self.client.emit('scrape', {
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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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downloaded: data.downloaded
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})
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}
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}
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}
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//
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// HELPERS
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//
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function toUInt16 (n) {
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var buf = new Buffer(2)
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buf.writeUInt16BE(n, 0)
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return buf
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}
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var MAX_UINT = 4294967295
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function toUInt64 (n) {
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if (n > MAX_UINT || typeof n === 'string') {
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var bytes = new BN(n).toArray()
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while (bytes.length < 8) {
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bytes.unshift(0)
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}
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return new Buffer(bytes)
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}
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return Buffer.concat([common.toUInt32(0), common.toUInt32(n)])
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}
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function bytewiseEncodeURIComponent (buf) {
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return encodeURIComponent(buf.toString('binary'))
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}
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