Issue #160: Provide Async Error Handling

Added Toast notification for unexpected errors
    On 401 and 403 Errors, user is redirected to login

webgoat-container/src/main/resources/static/js/goatApp/view/ErrorNotificationView.js

@@ -0,0 +1,35 @@
+define(['jquery',
+        'underscore',
+        'backbone'],
+    function($,
+             _,
+             Backbone) {
+        return Backbone.View.extend({
+            el:'#error-notification-container',
+            initialize: function() {
+                Backbone.on("error:unhandled", this.showNotification.bind(this));
+                this.hideNotification();
+                this.currentTimeout = null;
+            },
+
+            showNotification: function() {
+                var self = this;
+                if (!this.$el.is(':visible')) {
+                    this.$el.show(350);
+                }
+                if (this.currentTimeout != null) {
+                    window.clearTimeout(this.currentTimeout);
+                }
+                this.currentTimeout = window.setTimeout(function() {
+                    self.hideNotification();
+                    self.currentTimeout = null;
+                }, 3000);
+            },
+
+            hideNotification: function() {
+                if (this.$el.is(':visible')) {
+                    this.$el.hide(350);
+                }
+            }
+        });
+    });

webgoat-container/src/main/resources/static/js/goatApp/view/LessonContentView.js

@@ -2,17 +2,20 @@
 define(['jquery',
     'underscore',
     'backbone',
-    'libs/jquery.form'], 
+    'libs/jquery.form',
+    'goatApp/view/ErrorNotificationView'],
     function(
         $,
         _,
         Backbone,
-        JQueryForm) {
+        JQueryForm,
+        ErrorNotificationView) {
     return Backbone.View.extend({
         el:'#lesson-content-wrapper', //TODO << get this fixed up in DOM
 
         initialize: function(options) {
             options = options || {};
+            new ErrorNotificationView();
         },
 
         /* initial renering */