1 files changed, 26 insertions, 0 deletions
diff --git a/railties/lib/rails/rack/metal.rb b/railties/lib/rails/rack/metal.rb
new file mode 100644
index 0000000000..565f95d7c4
--- /dev/null
+++ b/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