This commit merges most of the work done by Piotr Sarnacki in his Ruby Summer of Code project.

His work brings several capabilities from app to engines, as routes, middleware stack, asset handling and much more. Please check Rails::Engine documentation for more refenrences.

Merge remote branch 'drogus/engines'

6 files changed, 45 insertions, 27 deletions

diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 7a1464c2aa..b37bc02127 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -221,11 +221,6 @@ module ActionController
     # Rails 2.x compatibility
     include ActionController::Compatibility
 
-    def self.inherited(klass)
-      super
-      klass.helper :all if klass.superclass == ActionController::Base
-    end
-
     ActiveSupport.run_load_hooks(:action_controller, self)
   end
-end
\ No newline at end of file
+end
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index 96ac138ba3..def28a0054 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -52,7 +52,11 @@ module ActionController
   class Metal < AbstractController::Base
     abstract!
 
-    attr_internal :env
+    attr_internal_writer :env
+
+    def env
+      @_env ||= {}
+    end
 
     # Returns the last part of the controller's name, underscored, without the ending
     # <tt>Controller</tt>. For instance, PostsController returns <tt>posts</tt>.
diff --git a/actionpack/lib/action_controller/metal/helpers.rb b/actionpack/lib/action_controller/metal/helpers.rb
index 4b6897c5dd..c5d7842db3 100644
--- a/actionpack/lib/action_controller/metal/helpers.rb
+++ b/actionpack/lib/action_controller/metal/helpers.rb
@@ -101,8 +101,12 @@ module ActionController
 
         # Extract helper names from files in <tt>app/helpers/**/*_helper.rb</tt>
         def all_application_helpers
+          all_helpers_from_path(helpers_path)
+        end
+
+        def all_helpers_from_path(path)
           helpers = []
-          Array.wrap(helpers_path).each do |path|
+          Array.wrap(path).each do |path|
             extract  = /^#{Regexp.quote(path.to_s)}\/?(.*)_helper.rb$/
             helpers += Dir["#{path}/**/*_helper.rb"].map { |file| file.sub(extract, '\1') }
           end
diff --git a/actionpack/lib/action_controller/metal/url_for.rb b/actionpack/lib/action_controller/metal/url_for.rb
index a51fc5b8e4..85c6b0a9b5 100644
--- a/actionpack/lib/action_controller/metal/url_for.rb
+++ b/actionpack/lib/action_controller/metal/url_for.rb
@@ -2,27 +2,19 @@ module ActionController
   module UrlFor
     extend ActiveSupport::Concern
 
-    include ActionDispatch::Routing::UrlFor
+    include AbstractController::UrlFor
 
     def url_options
-      super.reverse_merge(
+      options = {}
+      if _routes.equal?(env["action_dispatch.routes"])
+        options[:script_name] = request.script_name.dup
+      end
+
+      super.merge(options).reverse_merge(
         :host => request.host_with_port,
         :protocol => request.protocol,
         :_path_segments => request.symbolized_path_parameters
-      ).merge(:script_name => request.script_name)
-    end
-
-    def _routes
-      raise "In order to use #url_for, you must include routing helpers explicitly. " \
-            "For instance, `include Rails.application.routes.url_helpers"
-    end
-
-    module ClassMethods
-      def action_methods
-        @action_methods ||= begin
-          super - _routes.named_routes.helper_names
-        end
-      end
+      )
     end
   end
 end
diff --git a/actionpack/lib/action_controller/railtie.rb b/actionpack/lib/action_controller/railtie.rb
index cd2dfafbe6..0cb4041855 100644
--- a/actionpack/lib/action_controller/railtie.rb
+++ b/actionpack/lib/action_controller/railtie.rb
@@ -4,6 +4,8 @@ require "action_dispatch/railtie"
 require "action_view/railtie"
 require "active_support/deprecation/proxy_wrappers"
 require "active_support/deprecation"
+require "abstract_controller/railties/routes_helpers"
+require "action_controller/railties/paths"
 
 module ActionController
   class Railtie < Rails::Railtie
@@ -47,10 +49,11 @@ module ActionController
       options.javascripts_dir      ||= paths.public.javascripts.to_a.first
       options.stylesheets_dir      ||= paths.public.stylesheets.to_a.first
       options.page_cache_directory ||= paths.public.to_a.first
-      options.helpers_path         ||= paths.app.helpers.to_a
 
       ActiveSupport.on_load(:action_controller) do
-        include app.routes.url_helpers
+        include app.routes.mounted_helpers(:app)
+        extend ::AbstractController::Railties::RoutesHelpers.with(app.routes)
+        extend ::ActionController::Railties::Paths.with(app)
         options.each { |k,v| send("#{k}=", v) }
       end
     end
@@ -63,4 +66,4 @@ module ActionController
       ActionController::Routing::Routes = proxy
     end
   end
-end
\ No newline at end of file
+end
diff --git a/actionpack/lib/action_controller/railties/paths.rb b/actionpack/lib/action_controller/railties/paths.rb
new file mode 100644
index 0000000000..fa71d55946
--- /dev/null
+++ b/actionpack/lib/action_controller/railties/paths.rb
@@ -0,0 +1,20 @@
+module ActionController
+  module Railties
+    module Paths
+      def self.with(app)
+        Module.new do
+          define_method(:inherited) do |klass|
+            super(klass)
+            if namespace = klass.parents.detect {|m| m.respond_to?(:_railtie) }
+              klass.helpers_path = namespace._railtie.config.paths.app.helpers.to_a
+            else
+              klass.helpers_path = app.config.helpers_paths
+            end
+
+            klass.helper :all if klass.superclass == ActionController::Base
+          end
+        end
+      end
+    end
+  end
+end