throttling moved into tweets service

matthiasn · matthiasn · commit c52a8e2a2f46 · 2013-10-13T18:03:16.000+02:00
diff --git a/app/assets/javascripts/controllers.js b/app/assets/javascripts/controllers.js
@@ -4,7 +4,7 @@
 angular.module('birdwatch.controllers', ['birdwatch.services', 'charts.barchart', 'charts.wordcloud', 'ui.bootstrap']).
     controller('BirdWatchCtrl',function ($scope, $location, utils, barchart, wordcloud, $timeout, wordCount, cf, tweets) {
         $scope.prevSizeOpts = ['100', '500', '1000', '2000', '5000', '10000', '20000'];
-        $scope.prevSize = $scope.prevSizeOpts[3];
+        $scope.prevSize = $scope.prevSizeOpts[4];
         $scope.pageSizeOpts = [5, 10, 25, 50, 100];
         $scope.pageSize = $scope.pageSizeOpts[1];
         $scope.live = true;
@@ -31,16 +31,10 @@ angular.module('birdwatch.controllers', ['birdwatch.services', 'charts.barchart'
         var onTimeout = function () { updateTimeout = $timeout(onTimeout, 10000); };
         var updateTimeout = onTimeout();
 
-        var insertionCache = [];
-        // callback to perform when new tweets available
+        /** actions to perform when new tweets are available through the streaming connection */
         tweets.registerCallback(function (t) {
-            insertionCache = insertionCache.concat(t);      // every received item is appended to insertionCache.
-            _.throttle(function() {                         // throttle because every insertion triggers expensive
-                $scope.wordCount.insert(insertionCache);    // $scope.apply(), insert cache once every 2 seconds,
-                insertionCache = [];                        // then empty cache.
-                $scope.words = $scope.wordCount.getWords();
-            }, 2000)();
-
+            $scope.wordCount.insert(t);
+            $scope.words = $scope.wordCount.getWords();
             cf.add(t);
         });
 
diff --git a/app/assets/javascripts/services/tweets.js b/app/assets/javascripts/services/tweets.js
@@ -3,14 +3,12 @@
 /** tweets service, load previous tweets and receives subsequent live tweets for given query */
 angular.module('birdwatch.services').factory('tweets', function ($http, utils, $location) {
     var tweetFeed;
+    var tweetsCache = [];
     
     /** callback function to perform when new tweet(s) arrive */
     var onNewTweets = function (t) {};
     var registerCallback = function (callback) { onNewTweets = callback; };
 
-    /** handle incoming tweets: add to tweets array */
-    var addTweet = function (msg) { onNewTweets([utils.formatTweet(JSON.parse(msg.data))]); };
-
     /** Load previous Tweets, paginated. Recursive function, calls itself with the next chunk to load until
      *  eventually n, the remaining tweets to load, is not larger than 0 any longer. guarantees at least n hits
      *  if available, potentially more if (n % chunkSize != 0) */
@@ -20,8 +18,7 @@ angular.module('birdwatch.services').factory('tweets', function ($http, utils, $
                 .success(function (data) {
                     onNewTweets(data.hits.hits.reverse().map(function (t) { return t._source; }).map(utils.formatTweet));
                     loadPrev(searchString, n - chunkSize, chunkSize, offset + chunkSize);
-                }).error(function (data, status, headers, config) { }
-            );
+                }).error(function (data, status, headers, config) { });
         }
     };
 
@@ -36,10 +33,19 @@ angular.module('birdwatch.services').factory('tweets', function ($http, utils, $
         }
         else $location.path("");
 
+        /** handle incoming tweets: add to tweetsCache array, run callback at most every second */
+        var cachedCallback = function(msg) {
+            tweetsCache = tweetsCache.concat(utils.formatTweet(JSON.parse(msg.data)));
+            _.throttle(function() {        // throttle because insertion too expensive on high traffic searches
+                onNewTweets(tweetsCache);  // run callback with all items in cache
+                tweetsCache = [];          // then empty cache.
+            }, 1000)();
+        };
+
         tweetFeed = new EventSource("/tweetFeed?q=" + searchString);
-        tweetFeed.addEventListener("message", addTweet, false);
+        tweetFeed.addEventListener("message", cachedCallback, false);
 
-        loadPrev(searchString, prevSize, 100, 0);
+        loadPrev(searchString, prevSize, 500, 0); // load previous tweets in chunks of size 500
     };
 
     return { search: search, registerCallback: registerCallback};
