Added Rack middleware to handle static files.

railties/lib/initializer.rb

@@ -8,6 +8,7 @@
 require 'rails/plugin/locator'
 require 'rails/plugin/loader'
 require 'rails/gem_dependency'
+require 'rails/rack'
 
 
 RAILS_ENV = (ENV['RAILS_ENV'] || 'development').dup unless defined?(RAILS_ENV)

railties/lib/rails/rack.rb

+module Rails
+  module Rack
+    autoload :Static, "rails/rack/static"
+  end
+end

railties/lib/rails/rack/static.rb

+module Rails
+  module Rack
+    class Static
+      FILE_METHODS = %w(GET HEAD).freeze
+
+      def initialize(app)
+        @app = app
+        @file_server = ::Rack::File.new(File.join(RAILS_ROOT, "public"))
+      end
+
+      def call(env)
+        path        = env['PATH_INFO'].chomp('/')
+        method      = env['REQUEST_METHOD']
+        cached_path = (path.empty? ? 'index' : path) + ::ActionController::Base.page_cache_extension
+
+        if FILE_METHODS.include?(method)
+          if file_exist?(path)
+            return @file_server.call(env)
+          elsif file_exist?(cached_path)
+            env['PATH_INFO'] = cached_path
+            return @file_server.call(env)
+          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
+    end
+  end
+end