Fix/cache query representers (#5711)

* cache various query representers json representation

* sort by
* columns
* group by
* filter instance schemas

* fix custom option path

[ci skip]

lib/api/utilities/representer_to_json_cache.rb

@@ -0,0 +1,59 @@
+#-- encoding: UTF-8
+
+#-- copyright
+# OpenProject is a project management system.
+# Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2017 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+
+module API
+  module Utilities
+    module RepresenterToJsonCache
+      def to_json(*)
+        if json_cacheable?
+          OpenProject::Cache.fetch(*json_representer_name_cache_key, *json_cache_key) do
+            super
+          end
+        else
+          super
+        end
+      end
+
+      def json_cacheable?
+        true
+      end
+
+      def json_cache_key
+        raise NotImplementedError
+      end
+
+      private
+
+      def json_representer_name_cache_key
+        self.class.name.to_s.split('::') + ['json', I18n.locale]
+      end
+    end
+  end
+end

lib/api/v3/queries/columns/query_column_representer.rb

@@ -33,6 +33,8 @@ module API
     module Queries
       module Columns
         class QueryColumnRepresenter < ::API::Decorators::Single
+          include API::Utilities::RepresenterToJsonCache
+
           self_link path: 'query_column',
                     id_attribute: ->(*) { converted_name },
                     title_getter: ->(*) { represented.caption }
@@ -56,6 +58,10 @@ module API
           def convert_attribute(attribute)
             ::API::Utilities::PropertyNameConverter.from_ar_name(attribute)
           end
+
+          def json_cache_key
+            [represented.name, represented.caption]
+          end
         end
       end
     end

lib/api/v3/queries/columns/query_relation_of_type_column_representer.rb

@@ -39,6 +39,10 @@ module API
 
           property :relation_type
         end
+
+        def json_cache_key
+          [represented.name]
+        end
       end
     end
   end

lib/api/v3/queries/columns/query_relation_to_type_column_representer.rb

@@ -43,6 +43,10 @@ module API
           def _type
             'QueryColumn::RelationToType'
           end
+
+          def json_cache_key
+            [represented.name, represented.type.cache_key]
+          end
         end
       end
     end

lib/api/v3/queries/group_bys/query_group_by_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
@@ -32,9 +33,10 @@ module API
     module Queries
       module GroupBys
         class QueryGroupByRepresenter < ::API::Decorators::Single
+          include API::Utilities::RepresenterToJsonCache
+
           self_link id_attribute: ->(*) { converted_name },
                     title_getter: ->(*) { represented.caption }
-
           def initialize(model, *_)
             super(model, current_user: nil, embed_links: true)
           end
@@ -58,6 +60,10 @@ module API
           def convert_attribute(attribute)
             ::API::Utilities::PropertyNameConverter.from_ar_name(attribute)
           end
+
+          def json_cache_key
+            [represented.name, represented.caption]
+          end
         end
       end
     end

lib/api/v3/queries/schemas/assigned_to_filter_dependency_representer.rb

@@ -35,6 +35,14 @@ module API
         class AssignedToFilterDependencyRepresenter <
           PrincipalFilterDependencyRepresenter
 
+          def json_cache_key
+            if filter.project
+              super + [Setting.work_package_group_assignment?, filter.project.id]
+            else
+              super + [Setting.work_package_group_assignment?]
+            end
+          end
+
           private
 
           def filter_query

lib/api/v3/queries/schemas/category_filter_dependency_representer.rb

@@ -35,6 +35,10 @@ module API
         class CategoryFilterDependencyRepresenter <
           FilterDependencyRepresenter
 
+          def json_cache_key
+            super + [filter.project.id]
+          end
+
           def href_callback
             # This filter is only available inside projects
             api_v3_paths.categories(filter.project.identifier)

lib/api/v3/queries/schemas/custom_option_filter_dependency_representer.rb

@@ -47,7 +47,7 @@ module API
                                          value_representer: CustomOptions::CustomOptionRepresenter,
                                          link_factory: ->(value) {
                                            {
-                                             href: api_v3_paths.custom_option(value),
+                                             href: api_v3_paths.custom_option(value.id),
                                              title: value.to_s
                                            }
                                          },
@@ -55,6 +55,10 @@ module API
                                            value_required?
                                          }
 
+          def json_cache_key
+            super + [filter.custom_field.cache_key]
+          end
+
           private
 
           def type

lib/api/v3/queries/schemas/date_time_filter_dependency_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)

lib/api/v3/queries/schemas/filter_dependency_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
@@ -32,6 +33,8 @@ module API
     module Queries
       module Schemas
         class FilterDependencyRepresenter < ::API::Decorators::SchemaRepresenter
+          include API::Utilities::RepresenterToJsonCache
+
           def initialize(filter, operator, form_embedded: false)
             self.operator = operator
 
@@ -71,6 +74,10 @@ module API
             end
           end
 
+          def json_cache_key
+            [operator.to_sym, I18n.locale]
+          end
+
           private
 
           def value_required?
@@ -78,7 +85,7 @@ module API
           end
 
           def type
-            raise NotImplementedError, 'Subclass has to implement #href_callback'
+            raise NotImplementedError, 'Subclass has to implement #type'
           end
 
           def href_callback

lib/api/v3/queries/schemas/group_filter_dependency_representer.rb

@@ -35,6 +35,10 @@ module API
         class GroupFilterDependencyRepresenter <
           PrincipalFilterDependencyRepresenter
 
+          def json_cache_key
+            super + (filter.project.present? ? [filter.project.id] : [])
+          end
+
           private
 
           def filter_query

lib/api/v3/queries/schemas/id_filter_dependency_representer.rb

@@ -35,6 +35,10 @@ module API
         class IdFilterDependencyRepresenter <
           FilterDependencyRepresenter
 
+          def json_cache_key
+            super + (filter.project.present? ? [filter.project.id] : [])
+          end
+
           def href_callback
             if filter.project
               api_v3_paths.work_packages_by_project(filter.project.id)

lib/api/v3/queries/schemas/query_filter_instance_schema_api.rb

@@ -66,7 +66,7 @@ module API
                 filter_class = Query.find_registered_filter(ar_name)
 
                 if filter_class
-                  filter = filter_class.new
+                  filter = filter_class.new context: OpenStruct.new(project: nil)
                   filter.name = ar_name
 
                   single_representer.new(filter,

lib/api/v3/queries/schemas/query_filter_instance_schema_representer.rb

@@ -28,9 +28,6 @@
 # See doc/COPYRIGHT.rdoc for more details.
 #++
 
-require 'roar/decorator'
-require 'roar/json/hal'
-
 require 'queries/operators'
 
 module API
@@ -38,6 +35,8 @@ module API
     module Queries
       module Schemas
         class QueryFilterInstanceSchemaRepresenter < ::API::Decorators::SchemaRepresenter
+          include API::Utilities::RepresenterToJsonCache
+
           schema :name,
                  type: 'String',
                  writable: false,
@@ -124,7 +123,7 @@ module API
           end
 
           def dependencies
-            filter.available_operators.each_with_object({}) do |operator, hash|
+            @dependencies ||= filter.available_operators.each_with_object({}) do |operator, hash|
               path = api_v3_paths.query_operator(operator.to_query)
               value = FilterDependencyRepresenterFactory.create(filter,
                                                                 operator,
@@ -133,6 +132,19 @@ module API
               hash[path] = value
             end
           end
+
+          def json_cacheable?
+            dependencies
+              .values
+              .all?(&:json_cacheable?)
+          end
+
+          def json_cache_key
+            dependencies
+              .values
+              .flat_map(&:json_cache_key)
+              .uniq + [form_embedded, filter.name]
+          end
         end
       end
     end

lib/api/v3/queries/schemas/status_filter_dependency_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
@@ -11,7 +12,7 @@
 # Copyright (C) 2010-2013 the ChiliProject Team
 #
 # This program is free software; you can redistribute it and/or
-# modify it under the terms of the GNU General Public License
+# modif it under the terms of the GNU General Public License
 # as published by the Free Software Foundation; either version 2
 # of the License, or (at your option) any later version.
 #

lib/api/v3/queries/schemas/subproject_filter_dependency_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
@@ -34,6 +35,10 @@ module API
         class SubprojectFilterDependencyRepresenter <
           FilterDependencyRepresenter
 
+          def json_cache_key
+            super + [filter.project.id]
+          end
+
           def href_callback
             params = [ancestor: { operator: '=', values: [filter.project.id.to_s] }]
             escaped = CGI.escape(::JSON.dump(params))

lib/api/v3/queries/schemas/type_filter_dependency_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
@@ -34,6 +35,10 @@ module API
         class TypeFilterDependencyRepresenter <
           FilterDependencyRepresenter
 
+          def json_cache_key
+            super + (filter.project.present? ? [filter.project.id] : [])
+          end
+
           def href_callback
             if filter.project.nil?
               api_v3_paths.types

lib/api/v3/queries/schemas/user_filter_dependency_representer.rb

@@ -35,6 +35,10 @@ module API
         class UserFilterDependencyRepresenter <
           PrincipalFilterDependencyRepresenter
 
+          def json_cache_key
+            super + (filter.project.present? ? [filter.project.id] : [])
+          end
+
           private
 
           def filter_query

lib/api/v3/queries/schemas/version_filter_dependency_representer.rb

@@ -35,6 +35,10 @@ module API
         class VersionFilterDependencyRepresenter <
           FilterDependencyRepresenter
 
+          def json_cache_key
+            super + (filter.project.present? ? [filter.project.id] : [])
+          end
+
           def href_callback
             order = "sortBy=#{to_query [%i(name asc)]}"
 

lib/api/v3/queries/sort_bys/query_sort_by_representer.rb

@@ -1,4 +1,5 @@
 #-- encoding: UTF-8
+
 #-- copyright
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
@@ -32,6 +33,8 @@ module API
     module Queries
       module SortBys
         class QuerySortByRepresenter < ::API::Decorators::Single
+          include API::Utilities::RepresenterToJsonCache
+
           self_link id_attribute: ->(*) { self_link_params },
                     title_getter: ->(*) { represented.name }
 
@@ -64,6 +67,10 @@ module API
           def _type
             'QuerySortBy'
           end
+
+          def json_cache_key
+            [represented.column_caption, represented.direction_name]
+          end
         end
       end
     end

spec/lib/api/v3/queries/columns/query_property_column_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Columns::QueryPropertyColumnRepresenter do
+describe ::API::V3::Queries::Columns::QueryPropertyColumnRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:column) { Query.available_columns.detect { |column| column.name == :status } }
@@ -87,4 +87,49 @@ describe ::API::V3::Queries::Columns::QueryPropertyColumnRepresenter do
       end
     end
   end
+
+  describe 'caching' do
+    before do
+      # fill the cache
+      representer.to_json
+    end
+
+    it 'is cached' do
+      expect(representer)
+        .not_to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the caption (cf rename)' do
+      allow(column)
+        .to receive(:caption)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the name' do
+      allow(column)
+        .to receive(:name)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the locale' do
+      expect(representer)
+        .to receive(:to_hash)
+
+      I18n.with_locale(:de) do
+        representer.to_json
+      end
+    end
+  end
 end

spec/lib/api/v3/queries/columns/query_relation_of_type_column_representer_spec.rb

@@ -27,7 +27,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Columns::QueryRelationOfTypeColumnRepresenter do
+describe ::API::V3::Queries::Columns::QueryRelationOfTypeColumnRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:type) { { name: :label_relates_to, sym_name: :label_relates_to, order: 1, sym: :relation1 } }
@@ -60,7 +60,7 @@ describe ::API::V3::Queries::Columns::QueryRelationOfTypeColumnRepresenter do
     it 'has relationType attribute' do
       is_expected
         .to be_json_eql(type[:sym].to_json)
-              .at_path('relationType')
+        .at_path('relationType')
     end
 
     it 'has name attribute' do
@@ -69,4 +69,38 @@ describe ::API::V3::Queries::Columns::QueryRelationOfTypeColumnRepresenter do
         .at_path('name')
     end
   end
+
+  describe 'caching' do
+    before do
+      # fill the cache
+      representer.to_json
+    end
+
+    it 'is cached' do
+      expect(representer)
+        .not_to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the name' do
+      allow(column)
+        .to receive(:name)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the locale' do
+      expect(representer)
+        .to receive(:to_hash)
+
+      I18n.with_locale(:de) do
+        representer.to_json
+      end
+    end
+  end
 end

spec/lib/api/v3/queries/columns/query_relation_to_type_column_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Columns::QueryRelationToTypeColumnRepresenter do
+describe ::API::V3::Queries::Columns::QueryRelationToTypeColumnRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:type) { FactoryGirl.build_stubbed(:type) }
@@ -70,4 +70,49 @@ describe ::API::V3::Queries::Columns::QueryRelationToTypeColumnRepresenter do
         .at_path('name')
     end
   end
+
+  describe 'caching' do
+    before do
+      # fill the cache
+      representer.to_json
+    end
+
+    it 'is cached' do
+      expect(representer)
+        .not_to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the name' do
+      allow(column)
+        .to receive(:name)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the type' do
+      allow(type)
+        .to receive(:cache_key)
+        .and_return('a_different_one')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the locale' do
+      expect(representer)
+        .to receive(:to_hash)
+
+      I18n.with_locale(:de) do
+        representer.to_json
+      end
+    end
+  end
 end

spec/lib/api/v3/queries/group_bys/query_group_by_representer_spec.rb

@@ -1,4 +1,5 @@
 #-- copyright
+#
 # OpenProject is a project management system.
 # Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
 #
@@ -28,7 +29,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::GroupBys::QueryGroupByRepresenter do
+describe ::API::V3::Queries::GroupBys::QueryGroupByRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:column) { Query.available_columns.detect { |column| column.name == :status } }
@@ -87,4 +88,49 @@ describe ::API::V3::Queries::GroupBys::QueryGroupByRepresenter do
       end
     end
   end
+
+  describe 'caching' do
+    before do
+      # fill the cache
+      representer.to_json
+    end
+
+    it 'is cached' do
+      expect(representer)
+        .not_to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the caption (cf rename)' do
+      allow(column)
+        .to receive(:caption)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the name' do
+      allow(column)
+        .to receive(:name)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the locale' do
+      expect(representer)
+        .to receive(:to_hash)
+
+      I18n.with_locale(:de) do
+        representer.to_json
+      end
+    end
+  end
 end

spec/lib/api/v3/queries/schemas/assigned_to_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::AssignedToFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::AssignedToFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
@@ -155,5 +155,60 @@ describe ::API::V3::Queries::Schemas::AssignedToFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::All)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different work_package_group_assignment setting' do
+        allow(Setting)
+          .to receive(:work_package_group_assignment?)
+          .and_return(!Setting.work_package_group_assignment?)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/boolean_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::BooleanFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::BooleanFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
@@ -70,5 +70,39 @@ describe ::API::V3::Queries::Schemas::BooleanFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/category_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::CategoryFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::CategoryFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::CategoryFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::CategoryFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -75,5 +76,49 @@ describe ::API::V3::Queries::Schemas::CategoryFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/custom_option_filter_dependency_representer_spec.rb

@@ -28,13 +28,22 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::CustomOptionFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::CustomOptionFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:custom_field) { FactoryGirl.build_stubbed(:list_wp_custom_field) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:custom_field) do
+    cf = FactoryGirl.build_stubbed(:list_wp_custom_field)
+
+    allow(cf)
+      .to receive(:custom_options)
+      .and_return([FactoryGirl.build_stubbed(:custom_option),
+                   FactoryGirl.build_stubbed(:custom_option)])
+    cf
+  end
   let(:filter) do
-    filter = Queries::WorkPackages::Filter::CustomFieldFilter.new(context: project)
+    filter = Queries::WorkPackages::Filter::CustomFieldFilter.new(context: query)
     filter.custom_field = custom_field
     filter
   end
@@ -55,7 +64,7 @@ describe ::API::V3::Queries::Schemas::CustomOptionFilterDependencyRepresenter do
         let(:type) { '[]CustomOption' }
         let(:hrefs) do
           custom_field.custom_options.map do |value|
-            api_v3_paths.custom_option(value)
+            api_v3_paths.custom_option(value.id)
           end
         end
 
@@ -84,5 +93,50 @@ describe ::API::V3::Queries::Schemas::CustomOptionFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different cache_key' do
+        allow(custom_field)
+          .to receive(:cache_key)
+          .and_return('something else')
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/date_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::DateFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::DateFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::DueDateFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::DueDateFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -106,5 +107,40 @@ describe ::API::V3::Queries::Schemas::DateFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/date_time_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::DateTimeFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::DateTimeFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::CreatedAtFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::CreatedAtFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -95,5 +96,40 @@ describe ::API::V3::Queries::Schemas::DateTimeFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/float_filter_dependency_representer_spec.rb

@@ -28,13 +28,14 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::FloatFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::FloatFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
   let(:custom_field) { FactoryGirl.build_stubbed(:float_wp_custom_field) }
   let(:filter) do
-    filter = Queries::WorkPackages::Filter::CustomFieldFilter.new(context: project)
+    filter = Queries::WorkPackages::Filter::CustomFieldFilter.new(context: query)
     filter.custom_field = custom_field
     filter
   end
@@ -91,5 +92,40 @@ describe ::API::V3::Queries::Schemas::FloatFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/group_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::GroupFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::GroupFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
@@ -106,5 +106,49 @@ describe ::API::V3::Queries::Schemas::GroupFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/id_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::IdFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::IdFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
@@ -85,5 +85,49 @@ describe ::API::V3::Queries::Schemas::IdFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/integer_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::IntegerFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::IntegerFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::DoneRatioFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::DoneRatioFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -86,5 +87,39 @@ describe ::API::V3::Queries::Schemas::IntegerFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/priority_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::PriorityFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::PriorityFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::PriorityFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::PriorityFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -63,5 +64,39 @@ describe ::API::V3::Queries::Schemas::PriorityFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/project_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::ProjectFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::ProjectFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:filter) { Queries::WorkPackages::Filter::ProjectFilter.new }
@@ -74,5 +74,39 @@ describe ::API::V3::Queries::Schemas::ProjectFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/query_filter_instance_schema_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::QueryFilterInstanceSchemaRepresenter do
+describe ::API::V3::Queries::Schemas::QueryFilterInstanceSchemaRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:filter) { Queries::WorkPackages::Filter::StatusFilter.new }
@@ -56,6 +56,14 @@ describe ::API::V3::Queries::Schemas::QueryFilterInstanceSchemaRepresenter do
   let(:self_link) { 'bogus_self_path' }
   let(:project) { nil }
   let(:user) { FactoryGirl.build_stubbed(:user) }
+  let(:json_cacheable) { true }
+  let(:json_cache_key) { 'some key' }
+  let(:dependency) do
+    double('dependency',
+           to_hash: { 'lorem': 'ipsum' },
+           json_cacheable?: json_cacheable,
+           json_cache_key: json_cache_key)
+  end
 
   context 'generation' do
     before do
@@ -65,7 +73,7 @@ describe ::API::V3::Queries::Schemas::QueryFilterInstanceSchemaRepresenter do
           .with(filter,
                 operator,
                 form_embedded: form_embedded)
-          .and_return("lorem": "ipsum")
+          .and_return(dependency)
       end
     end
 
@@ -213,4 +221,69 @@ describe ::API::V3::Queries::Schemas::QueryFilterInstanceSchemaRepresenter do
       end
     end
   end
+
+  describe 'caching' do
+    before do
+      filter.available_operators.each do |operator|
+        allow(::API::V3::Queries::Schemas::FilterDependencyRepresenterFactory)
+          .to receive(:create)
+          .with(filter,
+                operator,
+                form_embedded: form_embedded)
+          .and_return(dependency)
+      end
+    end
+
+    before do
+      # fill the cache
+      instance.to_json
+    end
+
+    it 'is cached' do
+      expect(instance)
+        .not_to receive(:to_hash)
+
+      instance.to_json
+    end
+
+    context 'with an uncacheable dependency' do
+      let(:json_cacheable) { false }
+
+      it 'is not cached' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+    end
+
+    it 'busts the cache on the form_embedded attribute' do
+      instance.form_embedded = !form_embedded
+
+      expect(instance)
+        .to receive(:to_hash)
+
+      instance.to_json
+    end
+
+    it 'busts the cache on a different cache key from a dependency' do
+      allow(dependency)
+        .to receive(:json_cache_key)
+        .and_return(['and', 'now', 'to', 'something', 'completely', 'different'])
+
+      expect(instance)
+        .to receive(:to_hash)
+
+      instance.to_json
+    end
+
+    it 'busts the cache on changes to the locale' do
+      expect(instance)
+        .to receive(:to_hash)
+
+      I18n.with_locale(:de) do
+        instance.to_json
+      end
+    end
+  end
 end

spec/lib/api/v3/queries/schemas/role_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::RoleFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::RoleFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:filter) { Queries::WorkPackages::Filter::RoleFilter.new }
@@ -74,5 +74,39 @@ describe ::API::V3::Queries::Schemas::RoleFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/status_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::StatusFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::StatusFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:filter) { Queries::WorkPackages::Filter::StatusFilter.new }
@@ -80,5 +80,39 @@ describe ::API::V3::Queries::Schemas::StatusFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/subproject_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::SubprojectFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::SubprojectFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::SubprojectFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::SubprojectFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -74,5 +75,49 @@ describe ::API::V3::Queries::Schemas::SubprojectFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/text_filter_dependency_representer_spec.rb

@@ -28,11 +28,12 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::TextFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::TextFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
-  let(:filter) { Queries::WorkPackages::Filter::SubjectFilter.new(context: project) }
+  let(:query) { FactoryGirl.build_stubbed(:query, project: project) }
+  let(:filter) { Queries::WorkPackages::Filter::SubjectFilter.new(context: query) }
   let(:form_embedded) { false }
 
   let(:instance) do
@@ -74,5 +75,39 @@ describe ::API::V3::Queries::Schemas::TextFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/type_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::TypeFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::TypeFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
@@ -88,5 +88,49 @@ describe ::API::V3::Queries::Schemas::TypeFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/user_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::UserFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::UserFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed :project }
@@ -91,5 +91,49 @@ describe ::API::V3::Queries::Schemas::UserFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/schemas/version_filter_dependency_representer_spec.rb

@@ -28,7 +28,7 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::Schemas::VersionFilterDependencyRepresenter do
+describe ::API::V3::Queries::Schemas::VersionFilterDependencyRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:project) { FactoryGirl.build_stubbed(:project) }
@@ -104,5 +104,49 @@ describe ::API::V3::Queries::Schemas::VersionFilterDependencyRepresenter do
         end
       end
     end
+
+    describe 'caching' do
+      let(:operator) { Queries::Operators::Equals }
+      let(:other_project) { FactoryGirl.build_stubbed(:project) }
+
+      before do
+        # fill the cache
+        instance.to_json
+      end
+
+      it 'is cached' do
+        expect(instance)
+          .not_to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different operator' do
+        instance.send(:operator=, Queries::Operators::NotEquals)
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on a different project' do
+        query.project = other_project
+
+        expect(instance)
+          .to receive(:to_hash)
+
+        instance.to_json
+      end
+
+      it 'busts the cache on changes to the locale' do
+        expect(instance)
+          .to receive(:to_hash)
+
+        I18n.with_locale(:de) do
+          instance.to_json
+        end
+      end
+    end
   end
 end

spec/lib/api/v3/queries/sort_bys/query_sort_by_representer_spec.rb

@@ -28,15 +28,16 @@
 
 require 'spec_helper'
 
-describe ::API::V3::Queries::SortBys::QuerySortByRepresenter do
+describe ::API::V3::Queries::SortBys::QuerySortByRepresenter, clear_cache: true do
   include ::API::V3::Utilities::PathHelper
 
   let(:column_name) { 'status' }
   let(:direction) { 'desc' }
   let(:column) { Queries::WorkPackages::Columns::PropertyColumn.new(column_name) }
+  let(:decorator) { ::API::V3::Queries::SortBys::SortByDecorator.new(column, direction) }
   let(:representer) do
     described_class
-      .new(::API::V3::Queries::SortBys::SortByDecorator.new(column, direction))
+      .new(decorator)
   end
 
   subject { representer.to_json }
@@ -128,4 +129,49 @@ describe ::API::V3::Queries::SortBys::QuerySortByRepresenter do
       end
     end
   end
+
+  describe 'caching' do
+    before do
+      # fill the cache
+      representer.to_json
+    end
+
+    it 'is cached' do
+      expect(representer)
+        .not_to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the column_caption (cf rename)' do
+      allow(decorator)
+        .to receive(:column_caption)
+        .and_return('blubs')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on a different direction' do
+      allow(decorator)
+        .to receive(:direction_name)
+        .and_return('asc')
+
+      expect(representer)
+        .to receive(:to_hash)
+
+      representer.to_json
+    end
+
+    it 'busts the cache on changes to the locale' do
+      expect(representer)
+        .to receive(:to_hash)
+
+      I18n.with_locale(:de) do
+        representer.to_json
+      end
+    end
+  end
 end

spec/support/shared/clear_cache.rb

@@ -0,0 +1,38 @@
+#-- encoding: UTF-8
+
+#-- copyright
+# OpenProject is a project management system.
+# Copyright (C) 2012-2017 the OpenProject Foundation (OPF)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2017 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+
+RSpec.configure do |config|
+  config.before(:each) do |example|
+    clear_cache = example.metadata[:clear_cache]
+    if clear_cache
+      Rails.cache.clear
+    end
+  end
+end