thingsboard-memoizeit

diff --git a/ui/src/app/api/dashboard.service.js b/ui/src/app/api/dashboard.service.js
index 743fbe9..74b68d0 100644
--- a/ui/src/app/api/dashboard.service.js
+++ b/ui/src/app/api/dashboard.service.js
@@ -17,7 +17,14 @@ export default angular.module('thingsboard.api.dashboard', [])
     .factory('dashboardService', DashboardService).name;
 
 /*@ngInject*/
-function DashboardService($http, $q, $location, customerService) {
+function DashboardService($rootScope, $http, $q, $location, customerService) {
+
+    var stDiffPromise;
+
+    $rootScope.dadshboardServiceStateChangeStartHandle = $rootScope.$on('$stateChangeStart', function () {
+        stDiffPromise = undefined;
+    });
+
 
     var service = {
         assignDashboardToCustomer: assignDashboardToCustomer,
@@ -113,18 +120,23 @@ function DashboardService($http, $q, $location, customerService) {
     }
 
     function getServerTimeDiff() {
-        var deferred = $q.defer();
-        var url = '/api/dashboard/serverTime';
-        var ct1 = Date.now();
-        $http.get(url, { ignoreLoading: true }).then(function success(response) {
-            var ct2 = Date.now();
-            var st = response.data;
-            var stDiff = Math.ceil(st - (ct1+ct2)/2);
-            deferred.resolve(stDiff);
-        }, function fail() {
-            deferred.reject();
-        });
-        return deferred.promise;
+        if (stDiffPromise) {
+            return stDiffPromise;
+        } else {
+            var deferred = $q.defer();
+            stDiffPromise = deferred.promise;
+            var url = '/api/dashboard/serverTime';
+            var ct1 = Date.now();
+            $http.get(url, {ignoreLoading: true}).then(function success(response) {
+                var ct2 = Date.now();
+                var st = response.data;
+                var stDiff = Math.ceil(st - (ct1 + ct2) / 2);
+                deferred.resolve(stDiff);
+            }, function fail() {
+                deferred.reject();
+            });
+        }
+        return stDiffPromise;
     }
 
     function getDashboard(dashboardId) {

diff --git a/ui/src/app/api/subscription.js b/ui/src/app/api/subscription.js
index ac8cefe..7334165 100644
--- a/ui/src/app/api/subscription.js
+++ b/ui/src/app/api/subscription.js
@@ -80,9 +80,7 @@ export default class Subscription {
             this.alarms = [];
 
             this.originalTimewindow = null;
-            this.timeWindow = {
-                stDiff: this.ctx.stDiff
-            }
+            this.timeWindow = {};
             this.useDashboardTimewindow = options.useDashboardTimewindow;
 
             if (this.useDashboardTimewindow) {
@@ -124,9 +122,7 @@ export default class Subscription {
             this.data = [];
             this.hiddenData = [];
             this.originalTimewindow = null;
-            this.timeWindow = {
-                stDiff: this.ctx.stDiff
-            }
+            this.timeWindow = {};
             this.useDashboardTimewindow = options.useDashboardTimewindow;
             this.stateData = options.stateData;
             if (this.useDashboardTimewindow) {
@@ -213,27 +209,51 @@ export default class Subscription {
         }
     }
 
-    initAlarmSubscription() {
+    loadStDiff() {
         var deferred = this.ctx.$q.defer();
-        if (!this.ctx.aliasController) {
-            this.configureAlarmsData();
-            deferred.resolve();
-        } else {
-            var subscription = this;
-            this.ctx.aliasController.resolveAlarmSource(this.alarmSource).then(
-                function success(alarmSource) {
-                    subscription.alarmSource = alarmSource;
-                    subscription.configureAlarmsData();
+        if (this.ctx.getStDiff && this.timeWindow) {
+            this.ctx.getStDiff().then(
+                (stDiff) => {
+                    this.timeWindow.stDiff = stDiff;
                     deferred.resolve();
                 },
-                function fail() {
-                    deferred.reject();
+                () => {
+                    this.timeWindow.stDiff = 0;
+                    deferred.resolve();
                 }
             );
+        } else {
+            if (this.timeWindow) {
+                this.timeWindow.stDiff = 0;
+            }
+            deferred.resolve();
         }
         return deferred.promise;
     }
 
+    initAlarmSubscription() {
+        var deferred = this.ctx.$q.defer();
+        var subscription = this;
+        this.loadStDiff().then(() => {
+            if (!subscription.ctx.aliasController) {
+                subscription.configureAlarmsData();
+                deferred.resolve();
+            } else {
+                subscription.ctx.aliasController.resolveAlarmSource(subscription.alarmSource).then(
+                    function success(alarmSource) {
+                        subscription.alarmSource = alarmSource;
+                        subscription.configureAlarmsData();
+                        deferred.resolve();
+                    },
+                    function fail() {
+                        deferred.reject();
+                    }
+                );
+            }
+        });
+        return deferred.promise;
+    }
+
     configureAlarmsData() {
         var subscription = this;
         var registration;
@@ -252,22 +272,24 @@ export default class Subscription {
 
     initDataSubscription() {
         var deferred = this.ctx.$q.defer();
-        if (!this.ctx.aliasController) {
-            this.configureData();
-            deferred.resolve();
-        } else {
-            var subscription = this;
-            this.ctx.aliasController.resolveDatasources(this.datasources).then(
-                function success(datasources) {
-                    subscription.datasources = datasources;
-                    subscription.configureData();
-                    deferred.resolve();
-                },
-                function fail() {
-                    deferred.reject();
-                }
-            );
-        }
+        var subscription = this;
+        this.loadStDiff().then(() => {
+            if (!subscription.ctx.aliasController) {
+                subscription.configureData();
+                deferred.resolve();
+            } else {
+                subscription.ctx.aliasController.resolveDatasources(subscription.datasources).then(
+                    function success(datasources) {
+                        subscription.datasources = datasources;
+                        subscription.configureData();
+                        deferred.resolve();
+                    },
+                    function fail() {
+                        deferred.reject();
+                    }
+                );
+            }
+        });
         return deferred.promise;
     }
 

diff --git a/ui/src/app/components/dashboard.directive.js b/ui/src/app/components/dashboard.directive.js
index 1a675ce..417ddb1 100644
--- a/ui/src/app/components/dashboard.directive.js
+++ b/ui/src/app/components/dashboard.directive.js
@@ -75,7 +75,6 @@ function Dashboard() {
             prepareDashboardContextMenu: '&?',
             prepareWidgetContextMenu: '&?',
             loadWidgets: '&?',
-            getStDiff: '&?',
             onInit: '&?',
             onInitFailed: '&?',
             dashboardStyle: '=?',
@@ -102,8 +101,6 @@ function DashboardController($scope, $rootScope, $element, $timeout, $mdMedia, $
 
     vm.gridster = null;
 
-    vm.stDiff = 0;
-
     vm.isMobileDisabled = angular.isDefined(vm.isMobileDisabled) ? vm.isMobileDisabled : false;
 
     vm.isMobileSize = false;
@@ -500,7 +497,7 @@ function DashboardController($scope, $rootScope, $element, $timeout, $mdMedia, $
         sortWidgets();
     });
 
-    loadStDiff();
+    loadDashboard();
 
     function sortWidgets() {
         vm.widgets.sort(function (widget1, widget2) {
@@ -515,28 +512,7 @@ function DashboardController($scope, $rootScope, $element, $timeout, $mdMedia, $
     }
 
     function reload() {
-        loadStDiff();
-    }
-
-    function loadStDiff() {
-        if (vm.getStDiff) {
-            var promise = vm.getStDiff();
-            if (promise) {
-                promise.then(function (stDiff) {
-                    vm.stDiff = stDiff;
-                    loadDashboard();
-                }, function () {
-                    vm.stDiff = 0;
-                    loadDashboard();
-                });
-            } else {
-                vm.stDiff = 0;
-                loadDashboard();
-            }
-        } else {
-            vm.stDiff = 0;
-            loadDashboard();
-        }
+        loadDashboard();
     }
 
     function loadDashboard() {

diff --git a/ui/src/app/components/dashboard.tpl.html b/ui/src/app/components/dashboard.tpl.html
index 2887419..0fe24de 100644
--- a/ui/src/app/components/dashboard.tpl.html
+++ b/ui/src/app/components/dashboard.tpl.html
@@ -113,7 +113,6 @@
 										 stateController: vm.stateController,
 										 isEdit: vm.isEdit,
 										 isMobile: vm.isMobileSize,
-										 stDiff: vm.stDiff,
 										 dashboardTimewindow: vm.dashboardTimewindow,
 										 dashboardTimewindowApi: vm.dashboardTimewindowApi }">
 									</div>

diff --git a/ui/src/app/components/widget/widget.controller.js b/ui/src/app/components/widget/widget.controller.js
index a4846be..e81854c 100644
--- a/ui/src/app/components/widget/widget.controller.js
+++ b/ui/src/app/components/widget/widget.controller.js
@@ -21,7 +21,7 @@ import Subscription from '../../api/subscription';
 
 /*@ngInject*/
 export default function WidgetController($scope, $state, $timeout, $window, $element, $q, $log, $injector, $filter, $compile, tbRaf, types, utils, timeService,
-                                         datasourceService, alarmService, entityService, deviceService, visibleRect, isEdit, isMobile, stDiff, dashboardTimewindow,
+                                         datasourceService, alarmService, entityService, dashboardService, deviceService, visibleRect, isEdit, isMobile, dashboardTimewindow,
                                          dashboardTimewindowApi, widget, aliasController, stateController, widgetInfo, widgetType) {
 
     var vm = this;
@@ -159,7 +159,7 @@ export default function WidgetController($scope, $state, $timeout, $window, $ele
         widgetUtils: widgetContext.utils,
         dashboardTimewindowApi: dashboardTimewindowApi,
         types: types,
-        stDiff: stDiff,
+        getStDiff: dashboardService.getServerTimeDiff,
         aliasController: aliasController
     };
 

diff --git a/ui/src/app/dashboard/dashboard.controller.js b/ui/src/app/dashboard/dashboard.controller.js
index 8319a9d..160223c 100644
--- a/ui/src/app/dashboard/dashboard.controller.js
+++ b/ui/src/app/dashboard/dashboard.controller.js
@@ -170,7 +170,6 @@ export default function DashboardController(types, utils, dashboardUtils, widget
         }
     }
 
-    vm.getServerTimeDiff = getServerTimeDiff;
     vm.addWidget = addWidget;
     vm.addWidgetFromType = addWidgetFromType;
     vm.exportDashboard = exportDashboard;
@@ -334,10 +333,6 @@ export default function DashboardController(types, utils, dashboardUtils, widget
         }
     }
 
-    function getServerTimeDiff() {
-        return dashboardService.getServerTimeDiff();
-    }
-
     function loadDashboard() {
         if (vm.widgetEditMode) {
             var widget = {

diff --git a/ui/src/app/dashboard/dashboard.tpl.html b/ui/src/app/dashboard/dashboard.tpl.html
index 394a601..71fbc66 100644
--- a/ui/src/app/dashboard/dashboard.tpl.html
+++ b/ui/src/app/dashboard/dashboard.tpl.html
@@ -137,8 +137,7 @@
                                      dashboard-ctx="vm.dashboardCtx"
                                      is-edit="vm.isEdit"
                                      is-mobile="vm.forceDashboardMobileMode"
-                                     widget-edit-mode="vm.widgetEditMode"
-                                     get-st-diff="vm.getServerTimeDiff()">
+                                     widget-edit-mode="vm.widgetEditMode">
                 </tb-dashboard-layout>
             </div>
             <md-sidenav ng-if="vm.layouts.right.show"
@@ -157,8 +156,7 @@
                                      dashboard-ctx="vm.dashboardCtx"
                                      is-edit="vm.isEdit"
                                      is-mobile="vm.forceDashboardMobileMode"
-                                     widget-edit-mode="vm.widgetEditMode"
-                                     get-st-diff="vm.getServerTimeDiff()">
+                                     widget-edit-mode="vm.widgetEditMode">
                 </tb-dashboard-layout>
             </md-sidenav>
         </div>

diff --git a/ui/src/app/dashboard/layouts/dashboard-layout.directive.js b/ui/src/app/dashboard/layouts/dashboard-layout.directive.js
index 18926c3..9ce569f 100644
--- a/ui/src/app/dashboard/layouts/dashboard-layout.directive.js
+++ b/ui/src/app/dashboard/layouts/dashboard-layout.directive.js
@@ -29,8 +29,7 @@ export default function DashboardLayout() {
             dashboardCtx: '=',
             isEdit: '=',
             isMobile: '=',
-            widgetEditMode: '=',
-            getStDiff: '&?'
+            widgetEditMode: '='
         },
         controller: DashboardLayoutController,
         controllerAs: 'vm',

diff --git a/ui/src/app/dashboard/layouts/dashboard-layout.tpl.html b/ui/src/app/dashboard/layouts/dashboard-layout.tpl.html
index 90a10b1..d9c7c23 100644
--- a/ui/src/app/dashboard/layouts/dashboard-layout.tpl.html
+++ b/ui/src/app/dashboard/layouts/dashboard-layout.tpl.html
@@ -64,7 +64,6 @@
             prepare-dashboard-context-menu="vm.prepareDashboardContextMenu()"
             prepare-widget-context-menu="vm.prepareWidgetContextMenu(widget)"
             on-remove-widget="vm.removeWidget(event, widget)"
-            get-st-diff="vm.getStDiff()"
             on-init="vm.dashboardInited(dashboard)"
             on-init-failed="vm.dashboardInitFailed(e)"
             ignore-loading="vm.layoutCtx.ignoreLoading">

diff --git a/ui/src/app/entity/attribute/attribute-table.directive.js b/ui/src/app/entity/attribute/attribute-table.directive.js
index 62d2081..bb138ed 100644
--- a/ui/src/app/entity/attribute/attribute-table.directive.js
+++ b/ui/src/app/entity/attribute/attribute-table.directive.js
@@ -31,7 +31,7 @@ import AliasController from '../../api/alias-controller';
 /*@ngInject*/
 export default function AttributeTableDirective($compile, $templateCache, $rootScope, $q, $mdEditDialog, $mdDialog,
                                                 $mdUtil, $document, $translate, $filter, utils, types, dashboardUtils,
-                                                dashboardService, entityService, attributeService, widgetService) {
+                                                entityService, attributeService, widgetService) {
 
     var linker = function (scope, element, attrs) {
 
@@ -407,10 +407,6 @@ export default function AttributeTableDirective($compile, $templateCache, $rootS
             scope.getEntityAttributes(true);
         }
 
-        scope.getServerTimeDiff = function() {
-            return dashboardService.getServerTimeDiff();
-        }
-
         scope.addWidgetToDashboard = function($event) {
             if (scope.mode === 'widget' && scope.widgetsListCache.length > 0) {
                 var widget = scope.widgetsListCache[scope.widgetsCarousel.index][0];

diff --git a/ui/src/app/entity/attribute/attribute-table.tpl.html b/ui/src/app/entity/attribute/attribute-table.tpl.html
index 3dfad59..6f862ba 100644
--- a/ui/src/app/entity/attribute/attribute-table.tpl.html
+++ b/ui/src/app/entity/attribute/attribute-table.tpl.html
@@ -158,7 +158,6 @@
                 <tb-dashboard
                         alias-controller="aliasController"
                         widgets="widgets"
-                        get-st-diff="getServerTimeDiff()"
                         columns="20"
                         is-edit="false"
                         is-mobile-disabled="true"