2 files changed, 29 insertions, 3 deletions
diff --git a/railties/lib/rails/configuration.rb b/railties/lib/rails/configuration.rb
index 7c1d549c9a..7929cba2fe 100644
--- a/railties/lib/rails/configuration.rb
+++ b/railties/lib/rails/configuration.rb
@@ -4,11 +4,25 @@ module Rails
   # Temporarily separate the plugin configuration class from the main
   # configuration class while this bit is being cleaned up.
   class Railtie::Configuration
-
     def self.default
       @default ||= new
     end
 
+    def self.default_middleware_stack
+      ActionDispatch::MiddlewareStack.new.tap do |middleware|
+        middleware.use('ActionDispatch::Static', lambda { Rails.public_path }, :if => lambda { Rails.application.config.serve_static_assets })
+        middleware.use('::Rack::Lock', :if => lambda { !ActionController::Base.allow_concurrency })
+        middleware.use('::Rack::Runtime')
+        middleware.use('ActionDispatch::ShowExceptions', lambda { ActionController::Base.consider_all_requests_local })
+        middleware.use('ActionDispatch::Callbacks', lambda { ActionController::Dispatcher.prepare_each_request })
+        middleware.use(lambda { ActionController::Base.session_store }, lambda { ActionController::Base.session_options })
+        middleware.use('ActionDispatch::ParamsParser')
+        middleware.use('::Rack::MethodOverride')
+        middleware.use('::Rack::Head')
+        middleware.use('ActionDispatch::StringCoercion')
+      end
+    end
+
     attr_reader :middleware
 
     def initialize(base = nil)
@@ -17,7 +31,7 @@ module Rails
         @middleware = base.middleware.dup
       else
         @options    = Hash.new { |h,k| h[k] = ActiveSupport::OrderedOptions.new }
-        @middleware = ActionDispatch::MiddlewareStack.new
+        @middleware = self.class.default_middleware_stack
       end
     end
 
@@ -230,7 +244,7 @@ module Rails
     def log_level
       @log_level ||= RAILS_ENV == 'production' ? :info : :debug
     end
-    
+
     def time_zone
       @time_zone ||= "UTC"
     end
diff --git a/railties/test/application/middleware_test.rb b/railties/test/application/middleware_test.rb
index 1b9c8c30fc..df564011d3 100644
--- a/railties/test/application/middleware_test.rb
+++ b/railties/test/application/middleware_test.rb
@@ -55,6 +55,18 @@ module ApplicationTests
       assert_equal "Rack::Config", middleware.last
     end
 
+    test "insert middleware after" do
+      add_to_config "config.middleware.insert_after ActionDispatch::Static, Rack::Config"
+      boot!
+      assert_equal "Rack::Config", middleware.second
+    end
+
+    test "insert middleware before" do
+      add_to_config "config.middleware.insert_before ActionDispatch::Static, Rack::Config"
+      boot!
+      assert_equal "Rack::Config", middleware.first
+    end
+
     private
       def boot!
         require "#{app_path}/config/environment"