Include timestamp in polling to reduce server load

src/controllers/poll-controller.php

@@ -19,6 +19,13 @@ private function getValue($session, $vote)
     return intval($value);
   }
 
+  // Check if the session as changed since the last polling call
+  private function sessionUnchanged($session)
+  {
+    // Check if anything changed since the last polling call
+    return isset($_GET['last']) && $_GET['last'] >= $session->getLastAction()->getTimestamp();
+  }
+
   // Start a new poll in the session
   private function startPoll($sessionId, $topic)
   {
@@ -47,6 +54,7 @@ private function placeVote($sessionId, $memberId, $voteValue)
 
     // Fetch entities
     $session = $this->getSession($sessionId);
+    $session->setLastAction(new DateTime());
     $currentPoll = $session->getCurrentPoll();
     $member = $this->getMember($memberId);
 
@@ -57,8 +65,11 @@ private function placeVote($sessionId, $memberId, $voteValue)
     // Find or create vote
     foreach($currentPoll->getVotes() as $vote)
     {
-      if($vote->getMember() == $member)
-        $match = $vote;
+      if($vote->getMember() != $member)
+        continue;
+
+      $match = $vote;
+      break;
     }
 
     // Create vote if not found
@@ -81,7 +92,7 @@ private function placeVote($sessionId, $memberId, $voteValue)
     }
 
     // Save all to db
-    $this->saveAll([$match, $currentPoll]);
+    $this->saveAll([$session, $match, $currentPoll]);
     $this->saveAll($currentPoll->getVotes()->toArray());
   }
 
@@ -90,14 +101,23 @@ private function current($sessionId)
   {
     // Load the user-vote.php required for this
     include __DIR__ .  "/user-vote.php";
+
+    // Create reponse object
+    $response = new stdClass();
 
     $session = $this->getSession($sessionId);
+
+    // Check if anything changed since the last polling call
+    if($this->sessionUnchanged($session))
+    {
+      $response->unchanged = true;
+      return $response;
+    }
 
-    // Create reponse object
-    $response = new stdClass();
+    // Fill response object
     $response->name = $session->getName();
+    $response->timestamp = $session->getLastAction()->getTimestamp();
     $response->votes = array();
-
     // Include votes in response
     $currentPoll = $session->getCurrentPoll();
     if ($currentPoll == null)
@@ -131,23 +151,32 @@ private function current($sessionId)
 
   private function topic($sessionId)
   {
-      $session = $this->getSession($sessionId);
-      $currentPoll = $session->getCurrentPoll();
-
-      // Result object. Only votable until all votes received
-      $result = new stdClass();
-      if ($currentPoll == null)
-      {
-          $result->topic = "No topic";
-          $result->votable = false;
-      }
-      else
-      {
-          $result->topic = $currentPoll->getTopic();
-          $result->votable = $currentPoll->getResult() < 0;
-      }
+    $session = $this->getSession($sessionId);
 
+    // Check if anything changed since the last polling call
+    if($this->sessionUnchanged($session))
+    {
+      $result->unchanged = true;
       return $result;
+    }
+
+    $currentPoll = $session->getCurrentPoll();
+
+    // Result object. Only votable until all votes received
+    $result = new stdClass();
+    $result->timestamp = $session->getLastAction()->getTimestamp();
+    if ($currentPoll == null)
+    {
+        $result->topic = "No topic";
+        $result->votable = false;
+    }
+    else
+    {
+        $result->topic = $currentPoll->getTopic();
+        $result->votable = $currentPoll->getResult() < 0;
+    }
+
+    return $result;
   }
 
   public function execute()

src/controllers/session-controller.php

@@ -9,7 +9,7 @@ private function getAllSessions()
   {
     // Create query finding all active sessions
     $query = $this->entityManager->createQuery('SELECT s.id, s.name, s.isPrivate, count(m.id) memberCount  FROM Session s LEFT JOIN s.members m WHERE s.lastAction > ?1 GROUP BY s.id');
-    $query->setParameter(1, new DateTime('-2 hour'));
+    $query->setParameter(1, new DateTime('-1 hour'));
     $sessions = $query->getArrayResult();
     return $sessions;
   }

src/controllers/statistics-controller.php

@@ -11,7 +11,7 @@ private function loadPlugins($filter)
       foreach(glob(__DIR__ . '/statistics/*.php') as $file) {
         // Check if the plugin was selected in the filter
         $key = basename($file, ".php");
-        if($filter == null || in_array($key, $filter)) {
+        if($filter == null || sizeof($filter) == 0 || in_array($key, $filter)) {
           $plugin = include $file;
           $plugins[$key] = $plugin; 
         }

src/js/main.js

@@ -378,12 +378,19 @@ scrum.app.controller('MasterController', function ($http, $routeParams, $locatio
     if (scrum.current !== self)
       return;
 
-    $http.get("/api/poll/current?id=" + self.id).then(function(response){
+    $http.get("/api/poll/current?id=" + self.id + "&last=" + self.timestamp).then(function(response){
       var data = response.data;
       var result = data.result;
-      if(!data.success) {
-      	// Error handling
-      	return;
+
+      // Call succeeded, but execution failed
+      if (!data.success) {
+        setTimeout(pollVotes, scrum.pollingScale.scale(300));
+        return;
+      }
+      // Session was not modified
+      if (result.unchanged) {
+        setTimeout(pollVotes, scrum.pollingScale.scale(300));
+        return;
       }
 
       // Query statistics
@@ -393,6 +400,7 @@ scrum.app.controller('MasterController', function ($http, $routeParams, $locatio
 
       // Copy poll values      
       self.name = result.name;
+      self.timestamp = result.timestamp;
       self.votes = result.votes;
       self.flipped = result.flipped;
       self.consensus = result.consensus;
@@ -403,10 +411,10 @@ scrum.app.controller('MasterController', function ($http, $routeParams, $locatio
       }
 
       scrum.pollingScale.success();
-      setTimeout(pollVotes, scrum.pollingScale.scale(300));
+      setTimeout(pollVotes, scrum.pollingScale.scale(400));
     }, function(){
       scrum.pollingScale.failed();
-      setTimeout(pollVotes, scrum.pollingScale.scale(300)); 
+      setTimeout(pollVotes, scrum.pollingScale.scale(400)); 
     });
   }
 
@@ -491,16 +499,24 @@ scrum.app.controller('MemberController', function MemberController ($http, $loca
     if (scrum.current !== self) return; 
 
     // Update topic
-    $http.get("/api/poll/topic?sid=" + self.id).then(function(response){
+    $http.get("/api/poll/topic?sid=" + self.id + "&last=" + self.timestamp).then(function(response){
       var data = response.data;
       if(!data.success)
       {
       	self.reset();
+        setTimeout(update, scrum.pollingScale.scale(500));
       	return;
       }
 
       var result = data.result;
 
+      if (result.unchanged) {
+        setTimeout(update, scrum.pollingScale.scale(500));
+        return
+      }
+
+      self.timestamp = result.timestamp;
+
       // Voting was closed, get our peers votes
       if(self.votable && !result.votable) {
 

src/model/session.php

@@ -29,7 +29,7 @@ class Session
     /** @OneToMany(targetEntity="Poll", mappedBy="session", orphanRemoval=true) **/
     protected $polls;
 
-    /** @ManyToOne(targetEntity="Poll", fetch="EAGER", cascade={"remove"}) **/
+    /** @ManyToOne(targetEntity="Poll", cascade={"remove"}) **/
     protected $currentPoll;
 
     public function getId()