2 files changed, 46 insertions, 1 deletions
diff --git a/actionpack/lib/action_dispatch.rb b/actionpack/lib/action_dispatch.rb
index ff365dac68..38aaa6146e 100644
--- a/actionpack/lib/action_dispatch.rb
+++ b/actionpack/lib/action_dispatch.rb
@@ -34,10 +34,11 @@ module ActionDispatch
   autoload :Utils, 'action_dispatch/http/utils'
 
   autoload :Callbacks, 'action_dispatch/middleware/callbacks'
+  autoload :MiddlewareStack, 'action_dispatch/middleware/stack'
   autoload :ParamsParser, 'action_dispatch/middleware/params_parser'
   autoload :Rescue, 'action_dispatch/middleware/rescue'
   autoload :ShowExceptions, 'action_dispatch/middleware/show_exceptions'
-  autoload :MiddlewareStack, 'action_dispatch/middleware/stack'
+  autoload :Static, 'action_dispatch/middleware/static'
 
   autoload :Assertions, 'action_dispatch/testing/assertions'
   autoload :Integration, 'action_dispatch/testing/integration'
diff --git a/actionpack/lib/action_dispatch/middleware/static.rb b/actionpack/lib/action_dispatch/middleware/static.rb
new file mode 100644
index 0000000000..d7e88a54e4
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/static.rb
@@ -0,0 +1,44 @@
+require 'rack/utils'
+
+module ActionDispatch
+  class Static
+    FILE_METHODS = %w(GET HEAD).freeze
+
+    def initialize(app, root)
+      @app = app
+      @file_server = ::Rack::File.new(root)
+    end
+
+    def call(env)
+      path   = env['PATH_INFO'].chomp('/')
+      method = env['REQUEST_METHOD']
+
+      if FILE_METHODS.include?(method)
+        if file_exist?(path)
+          return @file_server.call(env)
+        else
+          cached_path = directory_exist?(path) ? "#{path}/index" : path
+          cached_path += ::ActionController::Base.page_cache_extension
+
+          if file_exist?(cached_path)
+            env['PATH_INFO'] = cached_path
+            return @file_server.call(env)
+          end
+        end
+      end
+
+      @app.call(env)
+    end
+
+    private
+      def file_exist?(path)
+        full_path = File.join(@file_server.root, ::Rack::Utils.unescape(path))
+        File.file?(full_path) && File.readable?(full_path)
+      end
+
+      def directory_exist?(path)
+        full_path = File.join(@file_server.root, ::Rack::Utils.unescape(path))
+        File.directory?(full_path) && File.readable?(full_path)
+      end
+  end
+end