bittorrent-tracker/lib/swarm.js
Feross Aboukhadijeh c75ca05479 swarm.announce() should always call callback
It’s important that calls to swarm.announce() always calls the callback
that it’s passed otherwise http announce/scrape requests
will hang (because res.end() is never called).

Also, since this swarm implementation is in-memory, we can get rid of
the callbacks to internal functions.

Lastly, fixed references to non-existent start() function.
2014-12-11 13:43:11 -08:00

110 lines
2.8 KiB
JavaScript

module.exports = Swarm
var debug = require('debug')('bittorrent-tracker')
// Regard this as the default implementation of an interface that you
// need to support when overriding Server.getSwarm()
function Swarm (infoHash, server) {
this.peers = {}
this.complete = 0
this.incomplete = 0
this.emit = server.emit.bind(server)
}
Swarm.prototype.announce = function (params, cb) {
var self = this
var peer = self.peers[params.addr]
// Dispatch announce event
if (!params.event || params.event === 'empty') params.event = 'update'
var fn = '_onAnnounce_' + params.event
if (self[fn]) {
self[fn](params, peer) // process event
if (params.left === 0 && peer) peer.complete = true
cb(null, {
complete: self.complete,
incomplete: self.incomplete,
peers: self._getPeers(params.numwant)
})
} else {
cb(new Error('invalid event'))
}
}
Swarm.prototype._onAnnounce_started = function (params, peer) {
if (peer) {
debug('unexpected `started` event from peer that is already in swarm')
return this._onAnnounce_update(params, peer) // treat as an update
}
if (params.left === 0) this.complete += 1
else this.incomplete += 1
peer = this.peers[params.addr] = {
ip: params.ip,
port: params.port,
peerId: params.peer_id
}
this.emit('start', params.addr)
}
Swarm.prototype._onAnnounce_stopped = function (params, peer) {
if (!peer) {
debug('unexpected `stopped` event from peer that is not in swarm')
return // do nothing
}
if (peer.complete) this.complete -= 1
else this.incomplete -= 1
this.peers[params.addr] = null
this.emit('stop', params.addr)
}
Swarm.prototype._onAnnounce_completed = function (params, peer) {
if (!peer) {
debug('unexpected `completed` event from peer that is not in swarm')
return this._onAnnounce_started(params, peer) // treat as a start
}
if (peer.complete) {
debug('unexpected `completed` event from peer that is already marked as completed')
return // do nothing
}
this.complete += 1
this.incomplete -= 1
peer.complete = true
this.emit('complete', params.addr)
}
Swarm.prototype._onAnnounce_update = function (params, peer) {
if (!peer) {
debug('unexpected `update` event from peer that is not in swarm')
return this._onAnnounce_started(params, peer) // treat as a start
}
this.emit('update', params.addr)
}
Swarm.prototype._getPeers = function (numwant) {
var peers = []
for (var peerId in this.peers) {
if (peers.length >= numwant) break
var peer = this.peers[peerId]
if (!peer) continue // ignore null values
peers.push({
'peer id': peer.peerId,
ip: peer.ip,
port: peer.port
})
}
return peers
}
Swarm.prototype.scrape = function (params, cb) {
cb(null, {
complete: this.complete,
incomplete: this.incomplete
})
}