mirror of
https://github.com/webtorrent/bittorrent-tracker.git
synced 2024-12-13 10:56:25 +00:00
568 lines
15 KiB
JavaScript
568 lines
15 KiB
JavaScript
module.exports = Client
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var bencode = require('bencode')
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var BN = require('bn.js')
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var common = require('./lib/common')
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var compact2string = require('compact2string')
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var debug = require('debug')('bittorrent-tracker')
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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 get = require('simple-get')
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var hat = require('hat')
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var http = require('http')
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var https = require('https')
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var inherits = require('inherits')
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var once = require('once')
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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, 'hex')
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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 || 50
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self._intervalMs = self._opts.interval || (30 * 60 * 1000) // default: 30 minutes
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debug('new client %s', self._infoHash.toString('hex'))
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if (typeof torrent.announce === 'string') torrent.announce = [ torrent.announce ]
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self._trackers = (torrent.announce || [])
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.filter(function (announceUrl) {
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var protocol = url.parse(announceUrl).protocol
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return protocol === 'udp:' || protocol === 'http:' || protocol === 'https:'
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})
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.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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/**
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* Simple convenience function to scrape a tracker for an infoHash without
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* needing to create a Client, pass it a parsed torrent, etc.
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* @param {string} announceUrl
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* @param {string} infoHash
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* @param {function} cb
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*/
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Client.scrape = function (announceUrl, infoHash, cb) {
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cb = once(cb)
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var dummy = {
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peerId: new Buffer('01234567890123456789'),
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port: 6881,
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torrent: {
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infoHash: infoHash,
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announce: [ announceUrl ]
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}
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}
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var client = new Client(dummy.peerId, dummy.port, dummy.torrent)
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client.once('error', cb)
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client.once('scrape', function (data) {
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cb(null, data)
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})
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client.scrape()
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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 %s', 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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var protocol = url.parse(self._announceUrl).protocol
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if (protocol === 'udp:') {
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self._requestImpl = self._requestUdp
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} else if (protocol === 'http:' || protocol === 'https:') {
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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` %s', self._announceUrl)
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self._announce(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` %s', self._announceUrl)
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self._announce(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` %s', self._announceUrl)
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self._announce(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` %s', self._announceUrl)
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self._announce(opts)
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}
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/**
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* Send an announce request to the tracker.
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* @param {Object} opts
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* @param {number=} opts.uploaded
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* @param {number=} opts.downloaded
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* @param {number=} opts.left (if not set, calculated automatically)
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*/
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Tracker.prototype._announce = function (opts) {
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var self = this
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opts = extend({
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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 != null && opts.left == null) {
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opts.left = self.client.torrentLength - (opts.downloaded || 0)
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}
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self._requestImpl(self._announceUrl, opts)
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}
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/**
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* Send a scrape request to the tracker.
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*/
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Tracker.prototype.scrape = function () {
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var self = this
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self._scrapeUrl = self._scrapeUrl || getScrapeUrl(self._announceUrl)
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if (!self._scrapeUrl) {
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debug('scrape not supported %s', 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` %s', self._announceUrl)
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self._requestImpl(self._scrapeUrl, { _scrape: true })
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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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Tracker.prototype._requestHttp = function (requestUrl, opts) {
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var self = this
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if (opts._scrape) {
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opts = extend({
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info_hash: self.client._infoHash.toString('binary')
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}, opts)
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} else {
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opts = extend({
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info_hash: self.client._infoHash.toString('binary'),
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peer_id: self.client._peerId.toString('binary'),
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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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}, opts)
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if (self._trackerId) {
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opts.trackerid = self._trackerId
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}
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}
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get.concat(requestUrl + '?' + common.querystringStringify(opts), function (err, data, res) {
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if (err) return self.client.emit('warning', err)
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if (res.statusCode !== 200) return self.client.emit('warning', new Error('Non-200 response code ' + res.statusCode + ' from ' + requestUrl))
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if (data && data.length) self._handleResponse(requestUrl, data)
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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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opts = opts || {}
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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) {
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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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if (opts._scrape) {
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scrape(msg.slice(8, 16))
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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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var addrs
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try {
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addrs = compact2string.multi(msg.slice(20))
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} catch (err) {
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return self.client.emit('warning', err)
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}
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addrs.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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// errors will often happen if a tracker is offline, so don't treat it as fatal
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self.client.emit('warning', new Error(message + ' (' + 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) {
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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('warning', 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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debug('failure from ' + requestUrl + ' (' + failure + ')')
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return self.client.emit('warning', 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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debug('warning from ' + requestUrl + ' (' + warning + ')')
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self.client.emit('warning', new Error(warning))
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}
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debug('response from ' + requestUrl)
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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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var addrs
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if (Buffer.isBuffer(data.peers)) {
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// tracker returned compact response
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try {
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addrs = compact2string.multi(data.peers)
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} catch (err) {
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return self.client.emit('warning', err)
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}
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addrs.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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self.client.emit('peer', peer.ip + ':' + peer.port)
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})
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}
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if (Buffer.isBuffer(data.peers6)) {
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// tracker returned compact response
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try {
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addrs = compact2string.multi6(data.peers6)
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} catch (err) {
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return self.client.emit('warning', err)
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}
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addrs.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.peers6)) {
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// tracker returned normal response
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data.peers6.forEach(function (peer) {
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var ip = /^\[/.test(peer.ip) || !/:/.test(peer.ip)
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? peer.ip /* ipv6 w/ brackets or domain name */
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: '[' + peer.ip + ']' /* ipv6 without brackets */
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self.client.emit('peer', ip + ':' + 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[self.client._infoHash.toString('binary')]
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if (!data) {
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self.client.emit('warning', 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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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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}
|
|
|
|
var UDP_TRACKER = /^udp:\/\//
|
|
var HTTP_SCRAPE_SUPPORT = /\/(announce)[^\/]*$/
|
|
|
|
function getScrapeUrl (announceUrl) {
|
|
if (announceUrl.match(UDP_TRACKER)) return announceUrl
|
|
var match = announceUrl.match(HTTP_SCRAPE_SUPPORT)
|
|
if (match) {
|
|
var i = match.index
|
|
return announceUrl.slice(0, i) + '/scrape' + announceUrl.slice(i + 9)
|
|
}
|
|
return null
|
|
}
|