Add new JS tracking heartbeat feature which replaces old one. New one is more performant and executes much less code on user websites.

New piwik.js tests included as well as an additional utility to make writing future tests easier (use jquery to parse tracker requests that are returned from fetchTrackedRequests). However tests don't currently pass since qunit is not super helpful for testing async code.

1 files changed, 100 insertions, 59 deletions

diff --git a/js/piwik.js b/js/piwik.js
index 05af4dbab8..16701cf08c 100644
--- a/js/piwik.js
+++ b/js/piwik.js
@@ -2198,7 +2198,7 @@ if (typeof Piwik !== 'object') {
                 configMinimumVisitTime,
 
                 // Recurring heart beat after initial ping (in milliseconds)
-                configHeartBeatTimer,
+                configHeartBeatDelay,
 
                 // Disallow hash tags in URL
                 configDiscardHashTag,
@@ -2287,10 +2287,13 @@ if (typeof Piwik !== 'object') {
                 linkTrackingEnabled = false,
 
                 // Guard against installing the activity tracker more than once per Tracker instance
-                activityTrackingInstalled = false,
+                heartBeatSetUp = false,
 
-                // Last activity timestamp
-                lastActivityTime,
+                // Timestamp of last tracker request sent to Piwik
+                lastTrackerRequestTime,
+
+                // Handle to the current heart beat timeout
+                heartBeatTimeout,
 
                 // Internal state of the pseudo click handler
                 lastButton,
@@ -2516,6 +2519,9 @@ if (typeof Piwik !== 'object') {
              * Send request
              */
             function sendRequest(request, delay, callback) {
+                if (request.indexOf('ping=') === -1) {
+                    lastTrackerRequestTime = (new Date()).getTime();
+                }
 
                 if (!configDoNotTrack && request) {
                     makeSureThereIsAGapAfterFirstTrackingRequestToPreventMultipleVisitorCreation(function () {
@@ -2528,6 +2534,10 @@ if (typeof Piwik !== 'object') {
                         setExpireDateTime(delay);
                     });
                 }
+
+                if (configHeartBeatDelay) {
+                    heartBeatUp();
+                }
             }
 
             function canSendBulkRequest(requests)
@@ -2618,16 +2628,6 @@ if (typeof Piwik !== 'object') {
             }
 
             /*
-             * Process all "activity" events.
-             * For performance, this function must have low overhead.
-             */
-            function activityHandler() {
-                var now = new Date();
-
-                lastActivityTime = now.getTime();
-            }
-
-            /*
              * Generate a pseudo-unique ID to fingerprint this user
              * 16 hexits = 64 bits
              * note: this isn't a RFC4122-compliant UUID
@@ -3183,47 +3183,84 @@ if (typeof Piwik !== 'object') {
                 sendRequest(request, configTrackerPause);
 
                 // send ping
-                if (configMinimumVisitTime && configHeartBeatTimer && !activityTrackingInstalled) {
-                    activityTrackingInstalled = true;
-
-                    // add event handlers; cross-browser compatibility here varies significantly
-                    // @see http://quirksmode.org/dom/events
-                    addEventListener(documentAlias, 'click', activityHandler);
-                    addEventListener(documentAlias, 'mouseup', activityHandler);
-                    addEventListener(documentAlias, 'mousedown', activityHandler);
-                    addEventListener(documentAlias, 'mousemove', activityHandler);
-                    addEventListener(documentAlias, 'mousewheel', activityHandler);
-                    addEventListener(windowAlias, 'DOMMouseScroll', activityHandler);
-                    addEventListener(windowAlias, 'scroll', activityHandler);
-                    addEventListener(documentAlias, 'keypress', activityHandler);
-                    addEventListener(documentAlias, 'keydown', activityHandler);
-                    addEventListener(documentAlias, 'keyup', activityHandler);
-                    addEventListener(windowAlias, 'resize', activityHandler);
-                    addEventListener(windowAlias, 'focus', activityHandler);
-                    addEventListener(windowAlias, 'blur', activityHandler);
-
-                    // periodic check for activity
-                    lastActivityTime = now.getTime();
-                    setTimeout(function heartBeat() {
-                        var requestPing;
-                        now = new Date();
-
-                        // there was activity during the heart beat period;
-                        // on average, this is going to overstate the visitDuration by configHeartBeatTimer/2
-                        if ((lastActivityTime + configHeartBeatTimer) > now.getTime()) {
-                            // send ping if minimum visit time has elapsed
-                            if (configMinimumVisitTime < now.getTime()) {
-                                requestPing = getRequest('ping=1', customData, 'ping');
-
-                                sendRequest(requestPing, configTrackerPause);
-                            }
+                if (configHeartBeatDelay) {
+                    setUpHeartBeat();
+                }
+            }
 
-                            // resume heart beat
-                            setTimeout(heartBeat, configHeartBeatTimer);
-                        }
-                        // else heart beat cancelled due to inactivity
-                    }, configHeartBeatTimer);
+            /*
+             * Setup event handlers and timeout for initial heart beat.
+             */
+            function setUpHeartBeat() {
+                if (heartBeatSetUp) {
+                    return;
                 }
+
+                heartBeatSetUp = true;
+
+                addEventListener(windowAlias, 'focus', function () {
+                    // since it's possible for a user to come back to a tab after several hours or more, we try to send
+                    // a ping if the page is active. (after the ping is sent, the heart beat timeout will be set)
+                    if (heartBeatPingIfActivity()) {
+                        return;
+                    }
+
+                    heartBeatUp();
+                });
+                addEventListener(windowAlias, 'blur', function () {
+                    heartBeatDown();
+                });
+
+                heartBeatUp();
+            }
+
+            /*
+             * Sets up the heart beat timeout.
+             */
+            function heartBeatUp(delay) {
+                if (heartBeatTimeout) {
+                    return;
+                }
+
+                heartBeatTimeout = setTimeout(function heartBeat() {
+                    heartBeatTimeout = null;
+                    if (heartBeatPingIfActivity()) {
+                        return;
+                    }
+
+                    var now = new Date(),
+                        heartBeatDelay = configHeartBeatDelay - (now.getTime() - lastTrackerRequestTime);
+                    heartBeatDelay = Math.min(configHeartBeatDelay, heartBeatDelay); // sanity check
+                    heartBeatUp(heartBeatDelay)
+                }, delay || configHeartBeatDelay);
+            }
+
+            /*
+             * Removes the heart beat timeout.
+             */
+            function heartBeatDown() {
+                if (!heartBeatTimeout) {
+                    return;
+                }
+
+                clearTimeout(heartBeatTimeout);
+                heartBeatTimeout = null;
+            }
+
+            /*
+             * If there was user activity since the last check, and it's been configHeartBeatDelay seconds
+             * since the last tracker, send a ping request (the heartbeat timeout will be reset by sendRequest).
+             */
+            function heartBeatPingIfActivity() {
+                var now = new Date();
+                if (lastTrackerRequestTime + configHeartBeatDelay < now.getTime()) {
+                    var requestPing = getRequest('ping=1', null, 'ping');
+                    sendRequest(requestPing, configTrackerPause);
+
+                    return true;
+                }
+
+                return false;
             }
 
             /*
@@ -4962,14 +4999,18 @@ if (typeof Piwik !== 'object') {
                 /**
                  * Set heartbeat (in seconds)
                  *
-                 * @param int minimumVisitLength
-                 * @param int heartBeatDelay
+                 * @param int heartBeatDelay Defaults to 15.
                  */
-                setHeartBeatTimer: function (minimumVisitLength, heartBeatDelay) {
-                    var now = new Date();
+                setHeartBeatTimer: function (heartBeatDelay) {
+                    configHeartBeatDelay = (heartBeatDelay || 15) * 1000;
+                },
 
-                    configMinimumVisitTime = now.getTime() + minimumVisitLength * 1000;
-                    configHeartBeatTimer = heartBeatDelay * 1000;
+                /**
+                 * Clear heartbeat.
+                 */
+                clearHeartBeat: function () {
+                    heartBeatDown();
+                    configHeartBeatDelay = null;
                 },
 
                 /**