Removing Metal from Rails 3.

If you have existing Metals, you have a few options:
* if your metal behaves like a middleware, add it to the
  middleware stack via config.middleware.use. You can use
  methods on the middleware stack to control exactly where
  it should go
* if it behaves like a Rack endpoint, you can link to it
  in the router. This will result in more optimal routing
  time, and allows you to remove code in your endpoint
  that matches specific URLs in favor of the more powerful
  handling in the router itself.

For the future, you can use ActionController::Metal to get
a very fast controller with the ability to opt-in to specific
controller features without paying the penalty of the full
controller stack.

Since Rails 3 is closer to Rack, the Metal abstraction is
no longer needed.

2 files changed, 1 insertions, 56 deletions

diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 1b8af370f7..f3a326f36d 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -9,7 +9,7 @@ module Rails
 
       attr_accessor :allow_concurrency, :cache_classes, :cache_store,
                     :encoding, :consider_all_requests_local, :dependency_loading,
-                    :filter_parameters,  :log_level, :logger, :metals,
+                    :filter_parameters,  :log_level, :logger,
                     :plugins, :preload_frameworks, :reload_engines, :reload_plugins,
                     :secret_token, :serve_static_assets, :session_options,
                     :time_zone, :whiny_nils
@@ -45,10 +45,6 @@ module Rails
         @middleware ||= app_middleware.merge_into(default_middleware_stack)
       end
 
-      def metal_loader
-        @metal_loader ||= Rails::Application::MetalLoader.new
-      end
-
       def paths
         @paths ||= begin
           paths = super
@@ -157,7 +153,6 @@ module Rails
           middleware.use('::ActionDispatch::ParamsParser')
           middleware.use('::Rack::MethodOverride')
           middleware.use('::ActionDispatch::Head')
-          middleware.use(lambda { metal_loader.build_middleware(metals) }, :if => lambda { metal_loader.metals.any? })
         end
       end
     end
diff --git a/railties/lib/rails/application/metal_loader.rb b/railties/lib/rails/application/metal_loader.rb
deleted file mode 100644
index 2a43fa7892..0000000000
--- a/railties/lib/rails/application/metal_loader.rb
+++ /dev/null
@@ -1,50 +0,0 @@
-require 'action_dispatch'
-
-module Rails
-  class Application
-    class MetalLoader
-      attr_reader :paths, :metals
-
-      def initialize
-        @paths, @metals = [], []
-      end
-
-      def build_middleware(list=nil)
-        load_metals!(list)
-        self
-      end
-
-      def new(app)
-        ActionDispatch::Cascade.new(@metals, app)
-      end
-
-      def name
-        ActionDispatch::Cascade.name
-      end
-      alias :to_s :name
-
-    protected
-
-      def load_metals!(list)
-        metals = []
-        list = Array(list || :all).map(&:to_sym)
-
-        paths.each do |path|
-          matcher = /\A#{Regexp.escape(path)}\/(.*)\.rb\Z/
-          Dir.glob("#{path}/**/*.rb").sort.each do |metal_path|
-            metal = metal_path.sub(matcher, '\1').to_sym
-            next unless list.include?(metal) || list.include?(:all)
-            require_dependency metal.to_s
-            metals << metal
-          end
-        end
-
-        metals = metals.sort_by do |m|
-          [list.index(m) || list.index(:all), m.to_s]
-        end
-
-        @metals = metals.map { |m| m.to_s.camelize.constantize }
-      end
-    end
-  end
-end