Temporarily store promises until they are resolved

The original commit simply stored promises into the cache,
which seemed to work in browsers but failed with karma/PhantomJS.

I'm not yet certain why that is, but I wanted to get rid of complex
objects in sessionStorage anyway, so this commit does:

* temporarily store running promises for a given key
* cache the resolved data directly

frontend/app/openproject-app.js

@@ -74,7 +74,8 @@ angular.module(
     'openproject.uiComponents',
     'openproject.helpers',
     'openproject.workPackages.config',
-    'openproject.workPackages.helpers'
+    'openproject.workPackages.helpers',
+    'angular-cache'
   ]);
 angular.module('openproject.helpers', ['openproject.services']);
 angular
@@ -191,8 +192,7 @@ var openprojectApp = angular.module('openproject', [
   'cgBusy',
   'openproject.api',
   'openproject.templates',
-  'monospaced.elastic',
-  'angular-cache'
+  'monospaced.elastic'
 ]);
 
 window.appBasePath = jQuery('meta[name=app_base_path]').attr('content') ||

frontend/app/services/cache-service.js

@@ -32,11 +32,16 @@ module.exports = function(
   $q,
   CacheFactory) {
 
-  var cacheName = 'openproject-cache';
-  var _cache = CacheFactory(cacheName, {
-    maxAge: 30 * 60 * 1000, // 30 mins
-    storageMode: 'sessionStorage'
-  });
+  var cacheName = 'openproject-cache',
+      _promises = {},
+      _cache = CacheFactory.get(cacheName);
+
+  if (!_cache) {
+    _cache = CacheFactory(cacheName, {
+      maxAge: 10 * 60 * 1000, // 10 mins
+      storageMode: 'sessionStorage',
+    });
+  }
 
   var CacheService = {
 
@@ -48,29 +53,40 @@ module.exports = function(
       return _cache.get(key);
     },
 
+    remove: function(key) {
+      _cache.remove(key);
+    },
+
     loadResource: function(resource, force) {
       var deferred = $q.defer(),
           key = resource.props.href,
           cached = CacheService.get(key);
 
+
+      // Got the result directly? Great.
+      if (cached && !force) {
+        deferred.resolve(cached);
+      }
+
       // Return an existing promise if it exists
       // Avoids intermittent requests while a first
       // is already underway.
-      if (cached && !force) {
-        return cached;
+      if (_promises[key]) {
+        return _promises[key];
       }
 
-      var promise = deferred.promise;
-      CacheService.cache(key, promise);
-
       resource.fetch().then(function(data) {
+        CacheService.cache(key, data);
         deferred.resolve(data);
       }, function() {
         deferred.reject();
+        CacheService.remove(key);
       });
 
+      var promise = deferred.promise;
+      _promises[key] = promise;
       return promise;
-    },
+    }
   };
 
   return CacheService;

frontend/app/work_packages/activities/user-activity-directive.js

@@ -75,7 +75,8 @@ module.exports = function($uiViewScroll,
       scope.userCanQuote = !!scope.workPackage.links.addComment;
       scope.accessibilityModeEnabled = ConfigurationService.accessibilityModeEnabled();
 
-      UserService.getUserByResource(scope.activity.links.user).then(function(user) {
+      var resource = UserService.getUserByResource(scope.activity.links.user);
+      resource.then(function(user) {
         scope.userId = user.props.id;
         scope.userName = user.props.name;
         scope.userAvatar = user.props.avatar;

frontend/tests/unit/tests/work_packages/activities/user-activity-directive-test.js

@@ -47,7 +47,7 @@ describe('userActivity Directive', function() {
       });
     });
 
-    beforeEach(inject(function($rootScope, $compile, $uiViewScroll, $timeout, $location, I18n, PathHelper, ActivityService, UsersHelper) {
+    beforeEach(inject(function($rootScope, $compile, $uiViewScroll, $timeout, $location, I18n, PathHelper, ActivityService, UsersHelper, UserService) {
       var html;
       html = '<user-activity work-package="workPackage" activity="activity" activity-no="activityNo" is-initial="isInitial" input-element-id="inputElementId"></user-activity>';
 
@@ -74,21 +74,20 @@ describe('userActivity Directive', function() {
           };
           scope.activity = {
             links: {
-              update: true,
               user: {
+                props: { href: '/api/v3/users/1' },
                 fetch: function() {
-                  return {
-                    then: function(cb) {
-                      cb({
-                        props: {
-                          id: 1,
-                          name: "John Doe",
-                          avatar: 'avatar.png',
-                          status: 1
-                        }
-                      }
-                    );}
-                  };
+                  var deferred = $q.defer();
+                  deferred.resolve({
+                    props: {
+                      id: 1,
+                      name: "John Doe",
+                      avatar: 'avatar.png',
+                      status: 1
+                    }
+                  });
+
+                  return deferred.promise;
                 }
               }
             },
@@ -114,7 +113,7 @@ describe('userActivity Directive', function() {
           };
           scope.isInitial = false;
           compile();
-        });
+        }));
 
         context("user's avatar", function() {
           it('should have an alt attribute', function() {
@@ -126,23 +125,28 @@ describe('userActivity Directive', function() {
           });
 
           describe('when being empty', function() {
-            beforeEach(function() {
-              scope.activity.links.user.fetch = function() {
-                return {
-                  then: function(cb) {
-                    cb({
-                      props: {
-                        id: 1,
-                        name: "John Doe",
-                        avatar: '',
-                        status: 1
-                      }
-                    });
-                  }
-                };
+            beforeEach(inject(function($q) {
+              scope.activity.links.user = {
+                props: {
+                  href: '/api/v3/users/2'
+                },
+                fetch: function() {
+                  var deferred = $q.defer();
+                  deferred.resolve({
+                    props: {
+                      id: 2,
+                      name: "John Doe",
+                      avatar: '',
+                      status: 1
+                    }
+                  });
+
+                  return deferred.promise;
+                }
               };
+
               compile();
-            });
+            }));
 
             it('should not be rendered', function() {
               expect(element.find('.avatar')).to.have.length(0);