Move middleware builder back to Rails::Rack::Metal without losing the new behavior.

actionpack/lib/action_dispatch/railtie.rb

@@ -8,35 +8,6 @@ module ActionDispatch
     require "action_dispatch/railties/subscriber"
     subscriber ActionDispatch::Railties::Subscriber.new
 
-    class MetalMiddlewareBuilder
-      def initialize(metals)
-        @metals = metals
-      end
-
-      def new(app)
-        ActionDispatch::Cascade.new(@metals, app)
-      end
-
-      def name
-        ActionDispatch::Cascade.name
-      end
-      alias_method :to_s, :name
-    end
-
-    initializer "action_dispatch.initialize_metal" do |app|
-      metal_root = "#{Rails.root}/app/metal"
-      load_list = app.config.metals || Dir["#{metal_root}/**/*.rb"]
-
-      metals = load_list.map { |metal|
-        metal = File.basename(metal.gsub("#{metal_root}/", ''), '.rb')
-        require_dependency metal
-        metal.camelize.constantize
-      }.compact
-
-      middleware = MetalMiddlewareBuilder.new(metals)
-      app.config.middleware.insert_before(:"ActionDispatch::ParamsParser", middleware)
-    end
-
     # Prepare dispatcher callbacks and run 'prepare' callbacks
     initializer "action_dispatch.prepare_dispatcher" do |app|
       # TODO: This used to say unless defined?(Dispatcher). Find out why and fix.

railties/lib/rails/configuration.rb

@@ -19,6 +19,7 @@ module Rails
         middleware.use('ActionDispatch::Cookies')
         middleware.use(lambda { ActionController::Base.session_store }, lambda { ActionController::Base.session_options })
         middleware.use('ActionDispatch::Flash', :if => lambda { ActionController::Base.session_store })
+        middleware.use(lambda { Rails::Rack::Metal.new(Rails.application.config.paths.app.metals.to_a, Rails.application.config.metals) })
         middleware.use('ActionDispatch::ParamsParser')
         middleware.use('::Rack::MethodOverride')
         middleware.use('::ActionDispatch::Head')

railties/lib/rails/rack.rb

@@ -1,7 +1,8 @@
 module Rails
   module Rack
-    autoload :Debugger, "rails/rack/debugger"
+    autoload :Debugger,  "rails/rack/debugger"
     autoload :LogTailer, "rails/rack/log_tailer"
-    autoload :Static, "rails/rack/static"
+    autoload :Metal,     "rails/rack/metal"
+    autoload :Static,    "rails/rack/static"
   end
 end

railties/lib/rails/rack/metal.rb

@@ -0,0 +1,26 @@
+require 'action_dispatch'
+
+module Rails
+  module Rack
+    class Metal
+      def initialize(metal_roots, metals=nil)
+        load_list = metals || Dir["{#{metal_roots.join(",")}}/**/*.rb"]
+
+        @metals = load_list.map { |metal|
+          metal = File.basename(metal, '.rb')
+          require_dependency metal
+          metal.camelize.constantize
+        }.compact
+      end
+
+      def new(app)
+        ActionDispatch::Cascade.new(@metals, app)
+      end
+
+      def name
+        ActionDispatch::Cascade.name
+      end
+      alias_method :to_s, :name
+    end
+  end
+end