randomize the peers that are given out

Author: feross

lib/swarm.js

@@ -1,6 +1,7 @@
 module.exports = Swarm
 
 var debug = require('debug')('bittorrent-tracker')
+var randomIterate = require('random-iterate')
 
 // Regard this as the default implementation of an interface that you
 // need to support when overriding Server.getSwarm()
@@ -22,7 +23,7 @@ Swarm.prototype.announce = function (params, cb) {
     cb(null, {
       complete: self.complete,
       incomplete: self.incomplete,
-      peers: self._getPeers(params.numwant, params.peer_id)
+      peers: self._getPeers(params.numwant)
     })
   } else {
     cb(new Error('invalid event'))
@@ -92,16 +93,13 @@ Swarm.prototype._onAnnounce_update = function (params, peer) {
   }
 }
 
-// TODO: randomize the peers that are given out
-Swarm.prototype._getPeers = function (numWant, fromPeerId) {
+Swarm.prototype._getPeers = function (numWant) {
   var peers = []
-  for (var peerId in this.peers) {
-    if (peers.length >= numWant) break
-    if (peerId === fromPeerId) continue // skip self
-
+  var ite = randomIterate(Object.keys(this.peers))
+  while (true) {
+    var peerId = ite()
+    if (peers.length >= numWant || peerId == null) return peers
     var peer = this.peers[peerId]
-    if (!peer) continue // ignore null values
-    peers.push(peer)
+    if (peer) peers.push(peer)
   }
-  return peers
 }

package.json

@@ -30,6 +30,7 @@
     "ip": "^0.3.0",
     "minimist": "^1.1.1",
     "once": "^1.3.0",
+    "random-iterate": "^1.0.1",
     "run-series": "^1.0.2",
     "simple-get": "^1.3.0",
     "simple-peer": "^5.0.0",

test/server.js

@@ -89,7 +89,7 @@ function serverTest (t, serverType, serverFamily) {
           })
 
           client2.once('peer', function (addr) {
-            t.equal(addr, clientAddr + ':6881')
+            t.ok(addr === clientAddr + ':6881' || addr === clientAddr + ':6882')
 
             client2.stop()
             client2.once('update', function (data) {