working implementation with tests
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Feross Aboukhadijeh
parent
9375b636ef
commit
bda3920643
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@ -0,0 +1,180 @@
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// TODO: add verification
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var BitField = require('BitField')
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var bncode = require('bncode')
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var EventEmitter = require('events').EventEmitter
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var inherits = require('inherits')
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var PIECE_LENGTH = 16 * 1024
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module.exports = function (metadata) {
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inherits(ut_metadata, EventEmitter)
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function ut_metadata (wire) {
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EventEmitter.call(this)
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this._wire = wire
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this._metadataComplete = false
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this._metadataSize = null
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this._remainingRejects = null // how many reject messages to tolerate before quitting
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this._fetching = false
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this._bitfield = new BitField(0)
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if (metadata) {
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this.gotMetadata(metadata)
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}
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}
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Object.defineProperty(ut_metadata.prototype, '_numPieces', {
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get: function () {
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return Math.ceil(this._metadataSize / PIECE_LENGTH)
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}
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})
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ut_metadata.prototype.onHandshake = function () {
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}
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ut_metadata.prototype.onExtendedHandshake = function (handshake) {
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this._metadataSize = handshake.metadata_size
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if (this._metadataSize && this._fetching) {
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this._requestPieces()
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}
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}
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ut_metadata.prototype.onMessage = function (buf) {
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var dict, trailer
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try {
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var str = buf.toString()
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var trailerIndex = str.indexOf('ee') + 2
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dict = bncode.decode(str.substring(0, trailerIndex))
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trailer = buf.slice(trailerIndex)
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} catch (err) {
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this.emit('warning', new Error('Could not decode ut_metadata message'))
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return
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}
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switch (dict.msg_type) {
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case 0:
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// ut_metadata request (from peer)
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// example: { 'msg_type': 0, 'piece': 0 }
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this._onRequest(dict.piece)
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break
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case 1:
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// ut_metadata data (in response to our request)
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// example: { 'msg_type': 1, 'piece': 0, 'total_size': 3425 }
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this._onData(dict.piece, trailer, dict.total_size)
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break
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case 2:
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// ut_metadata reject (peer doesn't have piece we requested)
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// { 'msg_type': 2, 'piece': 0 }
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this._onReject(dict.piece)
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break
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}
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}
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// Expose high-level, friendly API (fetch/cancel)
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ut_metadata.prototype.fetch = function () {
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if (this._metadataComplete) {
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return
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}
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this._fetching = true
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if (this._metadataSize) {
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this._requestPieces()
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}
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}
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ut_metadata.prototype.cancel = function () {
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this._fetching = false
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}
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ut_metadata.prototype.gotMetadata = function (_metadata) {
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this.metadata = _metadata
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this._metadataComplete = true
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this._metadataSize = this.metadata.length
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this._wire.extendedHandshake.metadata_size = this._metadataSize
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this.emit('metadata', this.metadata)
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}
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ut_metadata.prototype._send = function (dict, trailer) {
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var buf = bncode.encode(dict)
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if (Buffer.isBuffer(trailer)) {
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buf = Buffer.concat([buf, trailer])
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}
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this._wire.extended('ut_metadata', buf)
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}
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ut_metadata.prototype._request = function (piece) {
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this._send({ msg_type: 0, piece: piece })
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}
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ut_metadata.prototype._data = function (piece, buf, totalSize) {
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var msg = { msg_type: 1, piece: piece }
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if (typeof totalSize === 'number') {
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msg.total_size = totalSize
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}
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this._send(msg, buf)
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}
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ut_metadata.prototype._reject = function (piece) {
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this._send({ msg_type: 2, piece: piece })
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}
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ut_metadata.prototype._onRequest = function (piece) {
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if (this._metadataComplete) {
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var start = piece * PIECE_LENGTH
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var end = start + PIECE_LENGTH
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if (end > this._metadataSize) {
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end = this._metadataSize
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}
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var buf = this.metadata.slice(start, end)
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this._data(piece, buf, this._metadataSize)
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}
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}
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ut_metadata.prototype._onData = function (piece, buf, totalSize) {
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if (buf.length > PIECE_LENGTH) {
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return
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}
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buf.copy(this.metadata, piece * PIECE_LENGTH)
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this._bitfield.set(piece)
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this._checkDone()
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}
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ut_metadata.prototype._onReject = function (piece) {
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if (this._remainingRejects > 0 && this._fetching) {
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// If we haven't been rejected too much, then try to request the piece again
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this._request(piece)
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this._remainingRejects -= 1
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} else {
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this.emit('warning', new Error('Peer sent "reject" too much'))
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}
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}
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ut_metadata.prototype._requestPieces = function () {
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this.metadata = new Buffer(this._metadataSize)
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this._remainingRejects = this._numPieces
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for (var piece = 0; piece < this._numPieces; piece++) {
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this._request(piece)
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}
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}
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ut_metadata.prototype._checkDone = function () {
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var done = true
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for (var piece = 0; piece < this._numPieces; piece++) {
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if (!this._bitfield.get(piece)) {
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done = false
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break
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}
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}
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if (!done) return
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// TODO: verify
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this.gotMetadata(this.metadata)
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}
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return ut_metadata
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}
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@ -12,11 +12,13 @@
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},
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"dependencies": {
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"bncode": "^0.5.0",
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"bitfield": "^0.2.0",
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"inherits": "^2.0.1"
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},
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"devDependencies": {
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"tape": "2.x",
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"bittorrent-protocol": "^1.0.0"
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"bittorrent-protocol": "^1.0.0",
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"parse-torrent": "^0.6.0"
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},
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"homepage": "http://webtorrent.io",
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"keywords": [
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@ -0,0 +1,35 @@
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var fs = require('fs')
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var Protocol = require('bittorrent-protocol')
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var ut_metadata = require('../')
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var test = require('tape')
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// Used in multiple tests
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var metadata = fs.readFileSync(__dirname + '/torrents/leaves-magnet.torrent')
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test('wire.use(ut_metadata())', function (t) {
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var wire = new Protocol()
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wire.pipe(wire)
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wire.use(ut_metadata())
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t.ok(wire.ext('ut_metadata'))
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t.ok(wire.ext('ut_metadata').fetch)
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t.ok(wire.ext('ut_metadata').gotMetadata)
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t.ok(wire.ext('ut_metadata').cancel)
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t.notOk(wire.ext('ut_metadata').metadata)
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t.end()
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})
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test('wire.use(ut_metadata(metadata))', function (t) {
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var wire = new Protocol()
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wire.pipe(wire)
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wire.use(ut_metadata(metadata))
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t.ok(wire.ext('ut_metadata'))
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t.ok(wire.ext('ut_metadata').fetch)
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t.ok(wire.ext('ut_metadata').gotMetadata)
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t.ok(wire.ext('ut_metadata').cancel)
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t.equal(wire.ext('ut_metadata').metadata, metadata)
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t.end()
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})
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@ -0,0 +1,128 @@
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var fs = require('fs')
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var parseTorrent = require('parse-torrent')
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var Protocol = require('bittorrent-protocol')
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var ut_metadata = require('../')
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var test = require('tape')
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// Used in multiple tests
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var metadata = fs.readFileSync(__dirname + '/torrents/leaves-magnet.torrent')
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var parsedTorrent = parseTorrent(metadata)
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var id1 = new Buffer('01234567890123456789')
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var id2 = new Buffer('12345678901234567890')
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test('fetch()', function (t) {
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t.plan(3)
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var wire1 = new Protocol()
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var wire2 = new Protocol()
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wire1.pipe(wire2).pipe(wire1)
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wire1.use(ut_metadata(metadata)) // wire1 already has metadata
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wire2.use(ut_metadata()) // wire2 does not
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wire2.ext('ut_metadata').fetch()
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wire2.ext('ut_metadata').on('metadata', function (_metadata) {
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// got metadata!
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t.deepEqual(_metadata, metadata)
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})
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wire2.on('handshake', function (infoHash, peerId, extensions) {
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wire2.handshake(parsedTorrent.infoHash, id2)
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})
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wire2.on('extended', function (ext) {
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if (ext === 'handshake') {
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t.pass('got extended handshake')
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} else if (ext === 'ut_metadata') {
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t.pass('got extended ut_metadata message')
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// this is emitted for consistency's sake, but it's ignored
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// by the user since the ut_metadata package handles the
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// complexities internally
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} else {
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t.fail('unexpected handshake type')
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}
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})
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wire1.handshake(parsedTorrent.infoHash, id1)
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})
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test('fetch() then gotMetadata()', function (t) {
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t.plan(3)
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var wire1 = new Protocol()
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var wire2 = new Protocol()
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wire1.pipe(wire2).pipe(wire1)
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wire1.use(ut_metadata(metadata)) // wire1 already has metadata
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wire2.use(ut_metadata()) // wire2 does not
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wire2.ext('ut_metadata').fetch()
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// simulate that we just got metadata from another peer, so we set it immediately.
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// 'metadata' event should still get emitted later
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wire2.ext('ut_metadata').gotMetadata(metadata)
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wire2.ext('ut_metadata').on('metadata', function (_metadata) {
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// got metadata!
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t.deepEqual(_metadata, metadata)
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})
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wire2.on('handshake', function (infoHash, peerId, extensions) {
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wire2.handshake(parsedTorrent.infoHash, id2)
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})
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wire2.on('extended', function (ext) {
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if (ext === 'handshake') {
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t.pass('got extended handshake')
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} else if (ext === 'ut_metadata') {
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t.pass('got extended ut_metadata message')
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// this is emitted for consistency's sake, but it's ignored
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// by the user since the ut_metadata package handles the
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// complexities internally
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} else {
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t.fail('unexpected handshake type')
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}
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})
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wire1.handshake(parsedTorrent.infoHash, id1)
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})
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test('fetch() from peer without metadata', function (t) {
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t.plan(1)
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var wire1 = new Protocol()
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var wire2 = new Protocol()
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wire1.pipe(wire2).pipe(wire1)
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wire1.use(ut_metadata()) // neither wire has metadata
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wire2.use(ut_metadata())
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wire2.ext('ut_metadata').fetch()
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wire2.ext('ut_metadata').on('metadata', function () {
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t.fail('No "metadata" event should fire')
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})
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wire1.ext('ut_metadata').onMessage = function () {
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t.fail('No messages should be sent to wire1')
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// No messages should be sent because wire1 never sent metadata_size in the
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// extended handshake, so he doesn't have metadata
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}
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wire2.on('handshake', function (infoHash, peerId, extensions) {
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wire2.handshake(parsedTorrent.infoHash, id2)
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})
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wire2.on('extended', function (ext) {
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if (ext === 'handshake') {
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t.pass('got extended handshake')
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} else if (ext === 'ut_metadata') {
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t.fail('should not get extended ut_metadata message')
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} else {
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t.fail('unexpected handshake type')
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}
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})
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wire1.handshake(parsedTorrent.infoHash, id1)
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})
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