Remove all kinds of flickering

refs #72

application/controllers/GraphController.php

@@ -19,7 +19,7 @@ class GraphController extends MonitoringAwareController
      *
      * @var string[]
      */
-    protected $graphParamsNames = ['start', 'end', 'width', 'height', 'legend', 'template'];
+    protected $graphParamsNames = ['start', 'end', 'width', 'height', 'legend', 'template', 'cachebuster'];
 
     /**
      * The URL parameters for metrics filtering

library/Graphite/Graphing/Chart.php

@@ -158,6 +158,9 @@ class Chart
         $response
             ->setHeader('Content-Type', 'image/png', true)
             ->setHeader('Content-Disposition', 'inline; filename="graph.png"', true)
+            ->setHeader('Cache-Control', null, true)
+            ->setHeader('Expires', null, true)
+            ->setHeader('Pragma', null, true)
             ->setBody($image)
             ->sendResponse();
 

library/Graphite/Web/Widget/Graphs.php

@@ -210,14 +210,17 @@ abstract class Graphs extends AbstractWidget
                         ->setParam('start', $this->start)
                         ->setParam('end', $this->end)
                         ->setParam('width', $this->width)
-                        ->setParam('height', $this->height);
+                        ->setParam('height', $this->height)
+                        ->setParam('cachebuster', time() * 65536 + mt_rand(0, 65535));
                     if (! $this->compact) {
                         $imageUrl->setParam('legend', 1);
                     }
 
-                    $result[] = '<img src="';
+                    $result[] = '<img id="graphiteImg-';
+                    $result[] = md5((string) $imageUrl->without('cachebuster'));
+                    $result[] = '" src="';
                     $result[] = (string) $imageUrl;
-                    $result[] = '" class="graphiteImg" alt="" width="';
+                    $result[] = '" class="detach graphiteImg" alt="" width="';
                     $result[] = $this->width;
                     $result[] = '" height="';
                     $result[] = $this->height;

public/js/module.js

@@ -103,6 +103,63 @@
 
 }(Icinga));
 
+(function(Icinga, $) {
+    'use strict';
+
+    var extractUrlParams = /^([^?]*)\?(.+)$/;
+    var parseUrlParam = /^([^=]+)=(.*)$/;
+
+    function GraphiteCachebusterUpdater(icinga) {
+        Icinga.EventListener.call(this, icinga);
+
+        this.on('rendered', this.onRendered, this);
+    }
+
+    GraphiteCachebusterUpdater.prototype = new Icinga.EventListener();
+
+    GraphiteCachebusterUpdater.prototype.onRendered = function(event) {
+        $(event.target).find('img.graphiteImg').each(function() {
+            var e = $(this);
+            var src = e.attr('src');
+
+            if (typeof(src) !== 'undefined') {
+                var matchParams = extractUrlParams.exec(src);
+
+                if (matchParams !== null) {
+                    var urlParams = Object.create(null);
+
+                    matchParams[2].split('&').forEach(function(urlParam) {
+                        var matchParam = parseUrlParam.exec(urlParam);
+                        if (matchParam !== null) {
+                            urlParams[matchParam[1]] = matchParam[2];
+                        }
+                    });
+
+                    if (typeof(urlParams.cachebuster) !== 'undefined') {
+                        var cachebuster = parseInt(urlParams.cachebuster);
+
+                        if (cachebuster === cachebuster) {
+                            urlParams.cachebuster = (cachebuster + 1).toString();
+
+                            var renderedUrlParams = [];
+
+                            for (var urlParam in urlParams) {
+                                renderedUrlParams.push(urlParam + '=' + urlParams[urlParam]);
+                            }
+
+                            e.attr('src', matchParams[1] + '?' + renderedUrlParams.join('&'));
+                        }
+                    }
+                }
+            }
+        });
+    };
+
+    Icinga.Behaviors = Icinga.Behaviors || {};
+
+    Icinga.Behaviors.GraphiteCachebusterUpdater = GraphiteCachebusterUpdater;
+}(Icinga, jQuery));
+
 (function(Icinga, $) {
     'use strict';