Merge fef5e50 into a402180

README.md

@@ -91,7 +91,7 @@ After installing the server, you can run ```redis-cli``` to issue commands to re
 - Run ```git push heroku <your branch>:master``` which will push to Heroku and start up a dyno.
 - Run ```heroku open``` and view the app running in Heroku
 - Run ```heroku run bash``` then run ```mocha``` to execute the test suite
-
+- If you are running the app in more than one dyno, you will need to force the client to communicate with the server only using websockets. To do so, set the config variable SOCKETIO_TRANSPORT_PROTOCOL to websocket or run ```heroku config:set SOCKETIO_TRANSPORT_PROTOCOL=websocket```
 If you are running on Heroku and you want to use Google Analytics, store your tracking id in a Heroku config variable called `GOOGLE_ANALYTICS_ID`.
 
 ## Using Trace (by RisingStack) for application performance monitoring

index.js

@@ -54,6 +54,7 @@ function start() { // eslint-disable-line max-statements
 
   const app = express();
   const httpServer = require('http').Server(app);
+
   const io = require('socket.io')(httpServer);
   const socketIOSetup = require('./realtime/setupSocketIO');
   socketIOSetup.setupNamespace(io);

view/loadView.js

@@ -119,6 +119,7 @@ module.exports = function loadView(app, passport) {
           trackingId: viewConfig.trackingId,
           user: req.user,
           eventThrottle: viewConfig.realtimeEventThrottleMilliseconds,
+          transportProtocol: viewConfig.socketIOtransportProtocol,
         };
 
         const templateVars = Object.assign(

view/perspective/app.js

@@ -27,7 +27,8 @@ const ONE = 1;
 
 const DEBUG_REALTIME = window.location.href.split(/[&\?]/)
   .includes('debug=REALTIME');
-
+const WEBSOCKET_ONLY = window.location.href.split(/[&\?]/)
+  .includes('protocol=websocket');
 const REQ_HEADERS = {
   Authorization: u.getCookie('Authorization'),
   'X-Requested-With': 'XMLHttpRequest',
@@ -95,11 +96,36 @@ function handleEvent(eventData, eventTypeName) {
 function setupSocketIOClient(persBody) {
   const namespace = u.getNamespaceString(persBody);
 
+  /*
+   * if the transprotocol is set, initialize the socketio client with
+   *  the transport protocol options. The transProtocol variable is set in 
+   *  perspective.pug
+   */
+  const options = {};
+  const clientProtocol = transProtocol;
+  if (clientProtocol) {
+    /*
+     * options is used here to set the transport type. For example to only use
+     * websockets as the transport protocol the options object will be
+     * { transports: ['websocket'] }. The regex is used to trim the white spaces
+     * and since clientProtocol is a string of comma seperated values,
+     * the split function is used to split them out by comma and convert
+     * it to an array.
+     */
+    options.transports = clientProtocol.replace(/\s*,\s*/g, ',').split(',');
+  }
+
   /*
    * Note: The "io" variable is defined by the "/socket.io.js" script included
    * in perspective.pug.
    */
-  const socket = io(namespace);
+  let socket;
+  if (WEBSOCKET_ONLY) {
+    socket = io(namespace, { transports: ['websocket'] });
+  } else {
+    socket = io(namespace, options);
+  }
+
   socket.on(eventsQueue.eventType.INTRNL_SUBJ_ADD, (data) => {
     handleEvent(data, eventsQueue.eventType.INTRNL_SUBJ_ADD);
   });

view/perspective/perspective.pug

@@ -30,6 +30,9 @@ html(lang = 'en')
   script(src='/static/socket.io.js')
   script.
     var realtimeEventThrottleMilliseconds = #{eventThrottle};
+  script.
+    var transProtocol = '#{transportProtocol}';
+
   script
       if queryParams
           | var queryParams = !{queryParams}

viewConfig.js

@@ -26,10 +26,14 @@ const DEFAULT_THROTTLE_MILLISECS = 4000;
 const realtimeEventThrottleMilliseconds =
  pe.realtimeEventThrottleMilliseconds || DEFAULT_THROTTLE_MILLISECS;
 
+const socketIOtransportProtocol = pe.SOCKETIO_TRANSPORT_PROTOCOL || null;
 module.exports = {
   // Make the Google Analytics trackingId available in /view.
   trackingId: pe.GOOGLE_ANALYTICS_ID || 'N/A',
 
   // Make the throttle time available in /view.
   realtimeEventThrottleMilliseconds,
+
+  // Expose the socketIOtransportProtocol variable in the /view
+  socketIOtransportProtocol,
 };