From 94bdb8b4b072c9fadac77830325f727a14f93f85 Mon Sep 17 00:00:00 2001
From: Matthias Jentsch <matthias.jentsch@netways.de>
Date: Tue, 19 May 2015 16:35:44 +0200
Subject: [PATCH] Abort pending AJAX requests before page unload

Abort all pending requests before the page unload, to avoid confusing error messages during page reloads. Avoid rendering the site unusable in cases where the site is still being used after the beforeunload event.

fixes #7759
---
 public/js/icinga/events.js | 13 +++++++++++--
 public/js/icinga/loader.js | 14 ++++++++++----
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/public/js/icinga/events.js b/public/js/icinga/events.js
index cc927feb6..d458ab7fc 100644
--- a/public/js/icinga/events.js
+++ b/public/js/icinga/events.js
@@ -100,7 +100,7 @@
 
             // Destroy Icinga, clean up and interrupt pending requests on unload
             $( window ).on('unload', { self: this }, this.onUnload);
-            $( window ).on('beforeunload', { self: this }, this.onUnload);
+            $( window ).on('beforeunload', { self: this }, this.onBeforeUnload);
 
             // We catch scroll events in our containers
             $('.container').on('scroll', { self: this }, this.icinga.events.onContainerScroll);
@@ -153,6 +153,15 @@
             icinga.destroy();
         },
 
+        onBeforeUnload: function (event) {
+            var icinga = event.data.self.icinga;
+
+            // Browsers may call the error handler on all pending AJAX requests, when the page is reloaded,
+            // which could in turn cause needless error messages to show up in the frontend until the page is loaded.
+            // To circumvent this cancel all pending requests.
+            icinga.loader.cancelRequests();
+        },
+
         /**
          * A scroll event happened in one of our containers
          */
@@ -560,7 +569,7 @@
             $(window).off('resize', this.onWindowResize);
             $(window).off('load', this.onLoad);
             $(window).off('unload', this.onUnload);
-            $(window).off('beforeunload', this.onUnload);
+            $(window).off('beforeunload', this.onBeforeUnload);
             $(document).off('scroll', '.container', this.onContainerScroll);
             $(document).off('click', 'a', this.linkClicked);
             $(document).off('click', 'table.action tr[href]', this.rowSelected);
diff --git a/public/js/icinga/loader.js b/public/js/icinga/loader.js
index 99667ac1c..e01e03cec 100644
--- a/public/js/icinga/loader.js
+++ b/public/js/icinga/loader.js
@@ -793,16 +793,22 @@
         },
 
         /**
-         * On shutdown we kill all pending requests
+         * Cancel and dereference all pending requests and dereference this object
          */
         destroy: function() {
+            this.icinga.loader.cancelRequests();
+            this.icinga = null;
+            this.requests = {};
+        },
+
+        /**
+         * Cancel all pendings ajax requests
+         */
+        cancelRequests: function() {
             $.each(this.requests, function(id, request) {
                 request.abort();
             });
-            this.icinga = null;
-            this.requests = {};
         }
-
     };
 
 }(Icinga, jQuery));