cleanup peers that never get an answer

attempt to fix webtorrent/webtorrent#502

Author: feross

lib/client/websocket-tracker.js

@@ -18,6 +18,7 @@ var socketPool = {}
 
 var RECONNECT_VARIANCE = 30 * 1000
 var RECONNECT_MINIMUM = 5 * 1000
+var OFFER_TIMEOUT = 60000
 
 inherits(WebSocketTracker, Tracker)
 
@@ -199,11 +200,15 @@ WebSocketTracker.prototype._onSocketData = function (data) {
   }
 
   if (data.answer && data.peer_id) {
-    peer = self.peers[common.binaryToHex(data.offer_id)]
+    var offerId = common.binaryToHex(data.offer_id)
+    peer = self.peers[offerId]
     if (peer) {
       peer.id = common.binaryToHex(data.peer_id)
       peer.signal(data.answer)
       self.client.emit('peer', peer)
+
+      clearTimeout(peer.trackerTimeout)
+      self.peers[offerId] = null
     } else {
       debug('got unexpected answer: ' + JSON.stringify(data.answer))
     }
@@ -253,7 +258,6 @@ WebSocketTracker.prototype._generateOffers = function (numwant, cb) {
   var offers = []
   debug('generating %s offers', numwant)
 
-  // TODO: cleanup dead peers and peers that never get a return offer, from self.peers
   for (var i = 0; i < numwant; ++i) {
     generateOffer()
   }
@@ -274,6 +278,10 @@ WebSocketTracker.prototype._generateOffers = function (numwant, cb) {
       })
       checkDone()
     })
+    peer.trackerTimeout = setTimeout(function () {
+      peer.destroy()
+      self.peers[offerId] = null
+    }, OFFER_TIMEOUT)
   }
 
   function checkDone () {