harden the cursor streamer emit logic

bigbluebutton-html5/imports/api/cursor/server/handlers/cursorUpdate.js

 import { check } from 'meteor/check';
 import CursorStreamer from '/imports/api/cursor/server/streamer';
 import Logger from '/imports/startup/server/logger';
-
+import _ from 'lodash';
 
 const { streamerLog } = Meteor.settings.private.serverLog;
 
 const CURSOR_PROCCESS_INTERVAL = 30;
 
-let cursorQueue = {};
-let cursorReceiverIsRunning = false;
-
-const proccess = () => {
-  if (!Object.keys(cursorQueue).length) {
-    cursorReceiverIsRunning = false;
-    return;
-  }
-  cursorReceiverIsRunning = true;
+const cursorQueue = {};
 
+const proccess = _.throttle(() => {
   try {
     Object.keys(cursorQueue).forEach((meetingId) => {
-      CursorStreamer(meetingId).emit('message', { meetingId, cursors: cursorQueue[meetingId] });
+      try {
+        const cursors = cursorQueue[meetingId];
+        delete cursorQueue[meetingId];
+        CursorStreamer(meetingId).emit('message', { meetingId, cursors });
+
+        if (streamerLog) {
+          Logger.debug(`CursorUpdate process for meeting ${meetingId} has finished`);
+        }
+      } catch (error) {
+        Logger.error(`Error while trying to send cursor streamer data for meeting ${meetingId}. ${error}`);
+      }
     });
-    cursorQueue = {};
-
-    Meteor.setTimeout(proccess, CURSOR_PROCCESS_INTERVAL);
   } catch (error) {
-    Logger.error(`Error while trying to send cursor streamer data. ${error}`);
-    cursorReceiverIsRunning = false;
+    Logger.error(`Error while processing cursor queue. ${error}`);
   }
-};
+}, CURSOR_PROCCESS_INTERVAL);
 
 export default function handleCursorUpdate({ header, body }, meetingId) {
   const { userId } = header;
@@ -37,15 +36,12 @@ export default function handleCursorUpdate({ header, body }, meetingId) {
   check(meetingId, String);
   check(userId, String);
 
-  if (!cursorQueue.hasOwnProperty(meetingId)) {
+  if (!cursorQueue[meetingId]) {
     cursorQueue[meetingId] = {};
   }
 
-  if (streamerLog) {
-    Logger.debug(`CursorUpdate process for meeting ${meetingId} is running: ${cursorReceiverIsRunning}`);
-  }
-
   // overwrite since we dont care about the other positions
   cursorQueue[meetingId][userId] = body;
-  if (!cursorReceiverIsRunning) proccess();
+
+  proccess();
 }