Add support for autoloading nested related objects on ingredients

This takes the capabilities from AlchemyCMS/alchemy_cms#2523 and allows
pre-loading object graphs on ingredient's related objects.

app/controllers/alchemy/json_api/pages_controller.rb

@@ -38,10 +38,10 @@ def show
       def render_pages_json(allowed)
         # Only load pages with all includes when browser cache is stale
         jsonapi_filter(page_scope_with_includes, allowed) do |filtered|
-          # decorate with our page model that has a eager loaded elements collection
-          filtered_pages = filtered.result.map { |page| api_page(page) }
-          jsonapi_paginate(filtered_pages) do |paginated|
-            render jsonapi: paginated
+          jsonapi_paginate(filtered.result) do |paginated|
+            # decorate with our page model that has a eager loaded elements collection
+            decorated_pages = preload_ingredient_relations(paginated).map { |page| api_page(page) }
+            render jsonapi: decorated_pages
           end
         end
       end
@@ -74,7 +74,9 @@ def jsonapi_meta(pages)
       end
 
       def load_page
-        @page = load_page_by_id || load_page_by_urlname || raise(ActiveRecord::RecordNotFound)
+        @page = preload_ingredient_relations(
+          [load_page_by_id || load_page_by_urlname || raise(ActiveRecord::RecordNotFound)]
+        ).first
       end
 
       def load_page_by_id
@@ -109,6 +111,21 @@ def page_scope_with_includes
           )
       end
 
+      def preload_ingredient_relations(pages)
+        pages.map { |page| page.send(page_version_type) }.flat_map(&:elements).flat_map(&:ingredients).group_by(&:preload_relations).each do |preload_relations, ingredients|
+          preload(records: ingredients.map(&:related_object).compact, associations: preload_relations)
+        end
+        pages
+      end
+
+      def preload(records:, associations:)
+        if Rails::VERSION::MAJOR >= 7
+          ActiveRecord::Associations::Preloader.new(records: records, associations: associations).call
+        else
+          ActiveRecord::Associations::Preloader.new.preload(records, associations)
+        end
+      end
+
       def page_version_type
         :public_version
       end

app/serializers/alchemy/json_api/page_serializer.rb

@@ -33,15 +33,21 @@ class PageSerializer < BaseSerializer
 
       # All public elements of this page regardless of if they are fixed or nested.
       # Used for eager loading and should be used as the +include+ parameter of your query
-      has_many :all_elements, record_type: :element, serializer: ELEMENT_SERIALIZER
+      has_many :all_elements, record_type: :element, serializer: ELEMENT_SERIALIZER do |record|
+        record.public_version.element_repository.visible
+      end
 
       # The top level public, non-fixed elements of this page that - if present -
       # contains their nested_elements.
-      has_many :elements, record_type: :element, serializer: ELEMENT_SERIALIZER
+      has_many :elements, record_type: :element, serializer: ELEMENT_SERIALIZER do |record|
+        record.public_version.element_repository.visible.unfixed
+      end
 
       # The top level public, fixed elements of this page that - if present -
       # contains their nested_elements.
-      has_many :fixed_elements, record_type: :element, serializer: ELEMENT_SERIALIZER
+      has_many :fixed_elements, record_type: :element, serializer: ELEMENT_SERIALIZER do |record|
+        record.public_version.element_repository.visible.unfixed
+      end
     end
   end
 end