Configure backend only if available

app/controllers/spree/admin/prototypes_controller.rb

@@ -2,26 +2,31 @@
 
 module Spree
   module Admin
-    class PrototypesController < ResourceController
-      def show
-        if request.xhr?
-          render layout: false
-        else
-          redirect_to admin_prototypes_path
+    if defined? ::Spree::Backend
+      class PrototypesController < ResourceController
+        def show
+          if request.xhr?
+            render layout: false
+          else
+            redirect_to admin_prototypes_path
+          end
         end
-      end
 
-      def available
-        @prototypes = Prototype.order('name asc')
-        respond_with(@prototypes) do |format|
-          format.html { render layout: !request.xhr? }
-          format.js
+        def available
+          @prototypes = Prototype.order('name asc')
+          respond_with(@prototypes) do |format|
+            format.html { render layout: !request.xhr? }
+            format.js
+          end
         end
-      end
 
-      def select
-        @prototype ||= Prototype.find(params[:id])
-        @prototype_properties = @prototype.properties
+        def select
+          @prototype ||= Prototype.find(params[:id])
+          @prototype_properties = @prototype.properties
+        end
+      end
+    else
+      class PrototypesController
       end
     end
   end

config/initializers/spree.rb

@@ -1,18 +1,20 @@
 Rails.application.config.to_prepare do
   Spree::PermittedAttributes.product_attributes << :prototype_id
-  Spree::Backend::Config.configure do |config|
-    product_tab = config.menu_items.detect { |menu_item|
-      menu_item.label == :products
-    }
-    if product_tab.respond_to?(:children)
-      product_tab.children << Spree::BackendConfiguration::MenuItem.new(
-        condition: -> { can?(:admin, Spree::Prototype) },
-        url: :admin_prototypes_path,
-        label: :prototypes,
-        match_path: '/prototypes'
-      )
-    else
-      product_tab.sections << :prototypes
+  if defined?(Spree::Backend)
+    Spree::Backend::Config.configure do |config|
+      product_tab = config.menu_items.detect { |menu_item|
+        menu_item.label == :products
+      }
+      if product_tab.respond_to?(:children)
+        product_tab.children << Spree::BackendConfiguration::MenuItem.new(
+          condition: -> { can?(:admin, Spree::Prototype) },
+          url: :admin_prototypes_path,
+          label: :prototypes,
+          match_path: '/prototypes'
+        )
+      else
+        product_tab.sections << :prototypes
+      end
     end
   end
 end

lib/backend/controllers/spree/admin/products_controller_decorator.rb

@@ -19,7 +19,7 @@ def load_prototype
         @prototype = Spree::Prototype.find(params[resource][:prototype_id])
       end
 
-      ::Spree::Admin::ProductsController.prepend self
+      ::Spree::Admin::ProductsController.prepend self if defined? ::Spree::Admin::ProductsController
     end
   end
 end