Add throttling of usercount frames

package.json

@@ -2,7 +2,7 @@
   "author": "Calvin Montgomery",
   "name": "CyTube",
   "description": "Online media synchronizer and chat",
-  "version": "3.17.0",
+  "version": "3.17.1",
   "repository": {
     "url": "http://github.com/calzoneman/sync"
   },
@@ -27,6 +27,7 @@
     "http-errors": "^1.3.1",
     "jade": "^1.11.0",
     "json-typecheck": "^0.1.3",
+    "lodash": "^4.13.1",
     "morgan": "^1.6.1",
     "mysql": "^2.9.0",
     "nodemailer": "^1.4.0",

src/channel/channel.js

@@ -11,6 +11,9 @@ import * as ChannelStore from '../channel-storage/channelstore';
 import { ChannelStateSizeError } from '../errors';
 import Promise from 'bluebird';
 import { EventEmitter } from 'events';
+import { throttle } from '../util/throttle';
+
+const USERCOUNT_THROTTLE = 10000;
 
 class ReferenceCounter {
     constructor(channel) {
@@ -81,6 +84,9 @@ function Channel(name) {
     this.users = [];
     this.refCounter = new ReferenceCounter(this);
     this.flags = 0;
+    this.broadcastUsercount = throttle(() => {
+        this.broadcastAll("usercount", this.users.length);
+    }, USERCOUNT_THROTTLE);
     var self = this;
     db.channels.load(this, function (err) {
         if (err && err !== "Channel is not registered") {
@@ -403,7 +409,7 @@ Channel.prototype.acceptUser = function (user) {
     });
 
     this.sendUserlist([user]);
-    this.sendUsercount(this.users);
+    this.broadcastUsercount();
     if (!this.is(Flags.C_REGISTERED)) {
         user.socket.emit("channelNotRegistered");
     }
@@ -434,7 +440,7 @@ Channel.prototype.partUser = function (user) {
     Object.keys(this.modules).forEach(function (m) {
         self.modules[m].onUserPart(user);
     });
-    this.sendUsercount(this.users);
+    this.broadcastUsercount();
 
     this.refCounter.unref("Channel::user");
     user.die();

src/server.js

@@ -258,6 +258,7 @@ Server.prototype.unloadChannel = function (chan) {
     }
 
     Logger.syslog.log("Unloaded channel " + chan.name);
+    chan.broadcastUsercount.cancel();
     // Empty all outward references from the channel
     var keys = Object.keys(chan);
     for (var i in keys) {

src/util/throttle.js

@@ -0,0 +1,9 @@
+import lo from 'lodash';
+
+export function throttle(fn, timeout) {
+    return lo.debounce(fn, timeout, {
+        leading: true,
+        trailing: true,
+        maxWait: timeout
+    });
+}