Merge branch 'master' of https://github.com/rails/rails into performance_test

Conflicts:
	activesupport/lib/active_support/testing/performance.rb

75 files changed, 1864 insertions, 1235 deletions

diff --git a/actionpack/lib/abstract_controller/base.rb b/actionpack/lib/abstract_controller/base.rb
index 0951267fea..f67d0e558e 100644
--- a/actionpack/lib/abstract_controller/base.rb
+++ b/actionpack/lib/abstract_controller/base.rb
@@ -130,27 +130,39 @@ module AbstractController
       self.class.action_methods
     end
 
-    # Returns true if the name can be considered an action. This can
-    # be overridden in subclasses to modify the semantics of what
-    # can be considered an action.
+    # Returns true if a method for the action is available and
+    # can be dispatched, false otherwise.
     #
-    # For instance, this is overriden by ActionController to add
-    # the implicit rendering feature.
-    #
-    # ==== Parameters
-    # * <tt>name</tt> - The name of an action to be tested
-    #
-    # ==== Returns
-    # * <tt>TrueClass</tt>, <tt>FalseClass</tt>
-    def action_method?(name)
-      self.class.action_methods.include?(name)
+    # Notice that <tt>action_methods.include?("foo")</tt> may return
+    # false and <tt>available_action?("foo")</tt> returns true because
+    # available action consider actions that are also available
+    # through other means, for example, implicit render ones.
+    def available_action?(action_name)
+      method_for_action(action_name).present?
     end
 
     private
 
+      # Returns true if the name can be considered an action because
+      # it has a method defined in the controller.
+      #
+      # ==== Parameters
+      # * <tt>name</tt> - The name of an action to be tested
+      #
+      # ==== Returns
+      # * <tt>TrueClass</tt>, <tt>FalseClass</tt>
+      #
+      # :api: private
+      def action_method?(name)
+        self.class.action_methods.include?(name)
+      end
+
       # Call the action. Override this in a subclass to modify the
       # behavior around processing an action. This, and not #process,
       # is the intended way to override action dispatching.
+      #
+      # Notice that the first argument is the method to be dispatched
+      # which is *not* necessarily the same as the action name.
       def process_action(method_name, *args)
         send_action(method_name, *args)
       end
diff --git a/actionpack/lib/abstract_controller/callbacks.rb b/actionpack/lib/abstract_controller/callbacks.rb
index f7b2b7ff53..e8426bc52b 100644
--- a/actionpack/lib/abstract_controller/callbacks.rb
+++ b/actionpack/lib/abstract_controller/callbacks.rb
@@ -13,8 +13,8 @@ module AbstractController
 
     # Override AbstractController::Base's process_action to run the
     # process_action callbacks around the normal behavior.
-    def process_action(method_name, *args)
-      run_callbacks(:process_action, method_name) do
+    def process_action(*args)
+      run_callbacks(:process_action, action_name) do
         super
       end
     end
diff --git a/actionpack/lib/abstract_controller/helpers.rb b/actionpack/lib/abstract_controller/helpers.rb
index 20f8601a8e..dc9778a416 100644
--- a/actionpack/lib/abstract_controller/helpers.rb
+++ b/actionpack/lib/abstract_controller/helpers.rb
@@ -4,8 +4,6 @@ module AbstractController
   module Helpers
     extend ActiveSupport::Concern
 
-    include Rendering
-
     included do
       class_attribute :_helpers
       self._helpers = Module.new
@@ -112,17 +110,6 @@ module AbstractController
         default_helper_module! unless anonymous?
       end
 
-      private
-      # Makes all the (instance) methods in the helper module available to templates
-      # rendered through this controller.
-      #
-      # ==== Parameters
-      # * <tt>module</tt> - The module to include into the current helper module
-      #   for the class
-      def add_template_helper(mod)
-        _helpers.module_eval { include mod }
-      end
-
       # Returns a list of modules, normalized from the acceptable kinds of
       # helpers with the following behavior:
       #
@@ -155,6 +142,17 @@ module AbstractController
         end
       end
 
+      private
+      # Makes all the (instance) methods in the helper module available to templates
+      # rendered through this controller.
+      #
+      # ==== Parameters
+      # * <tt>module</tt> - The module to include into the current helper module
+      #   for the class
+      def add_template_helper(mod)
+        _helpers.module_eval { include mod }
+      end
+
       def default_helper_module!
         module_name = name.sub(/Controller$/, '')
         module_path = module_name.underscore
diff --git a/actionpack/lib/abstract_controller/layouts.rb b/actionpack/lib/abstract_controller/layouts.rb
index d1b87b67ee..8f73e244d7 100644
--- a/actionpack/lib/abstract_controller/layouts.rb
+++ b/actionpack/lib/abstract_controller/layouts.rb
@@ -292,15 +292,15 @@ module AbstractController
       end
     end
 
-    attr_writer :action_has_layout
+    attr_internal_writer :action_has_layout
 
     def initialize(*)
-      @action_has_layout = true
+      @_action_has_layout = true
       super
     end
 
     def action_has_layout?
-      @action_has_layout
+      @_action_has_layout
     end
 
   private
diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index 66f6d0eebb..ab2c532859 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -32,9 +32,13 @@ module AbstractController
 
   module Rendering
     extend ActiveSupport::Concern
-
     include AbstractController::ViewPaths
 
+    included do
+      config_accessor :protected_instance_variables, :instance_reader => false
+      self.protected_instance_variables = []
+    end
+
     # Overwrite process to setup I18n proxy.
     def process(*) #:nodoc:
       old_config, I18n.config = I18n.config, I18nProxy.new(I18n.config, lookup_context)
@@ -46,46 +50,27 @@ module AbstractController
     module ClassMethods
       def view_context_class
         @view_context_class ||= begin
-          controller = self
-          Class.new(ActionView::Base) do
-            if controller.respond_to?(:_routes) && controller._routes
-              include controller._routes.url_helpers
-              include controller._routes.mounted_helpers
-            end
-
-            if controller.respond_to?(:_helpers)
-              include controller._helpers
-
-              # TODO: Fix RJS to not require this
-              self.helpers = controller._helpers
-            end
-          end
+          routes  = _routes  if respond_to?(:_routes)
+          helpers = _helpers if respond_to?(:_helpers)
+          ActionView::Base.prepare(routes, helpers)
         end
       end
+    end
 
-      def parent_prefixes
-        @parent_prefixes ||= begin
-          parent_controller = superclass
-          prefixes = []
-
-          until parent_controller.abstract?
-            prefixes << parent_controller.controller_path
-            parent_controller = parent_controller.superclass
-          end
+    attr_internal_writer :view_context_class
 
-          prefixes
-        end
-      end
+    # Explicitly define protected_instance_variables so it can be
+    # inherited and overwritten by other modules if needed.
+    def protected_instance_variables
+      config.protected_instance_variables
     end
 
-    attr_writer :view_context_class
-
     def view_context_class
-      @view_context_class || self.class.view_context_class
+      @_view_context_class || self.class.view_context_class
     end
 
     def initialize(*)
-      @view_context_class = nil
+      @_view_context_class = nil
       super
     end
 
@@ -99,22 +84,27 @@ module AbstractController
     #
     # Override this method in a module to change the default behavior.
     def view_context
-      view_context_class.new(lookup_context, view_assigns, self)
+      view_context_class.new(view_renderer, view_assigns, self)
+    end
+
+    # Returns an object that is able to render templates.
+    def view_renderer
+      @_view_renderer ||= ActionView::Renderer.new(lookup_context)
     end
 
     # Normalize arguments, options and then delegates render_to_body and
     # sticks the result in self.response_body.
     def render(*args, &block)
-      self.response_body = render_to_string(*args, &block)
+      options = _normalize_render(*args, &block)
+      self.response_body = render_to_body(options)
     end
 
     # Raw rendering of a template to a string. Just convert the results of
-    # render_to_body into a String.
+    # render_response into a String.
     # :api: plugin
     def render_to_string(*args, &block)
-      options = _normalize_args(*args, &block)
-      _normalize_options(options)
-      render_to_body(options).tap { self.response_body = nil }
+      options = _normalize_render(*args, &block)
+      render_to_body(options)
     end
 
     # Raw rendering of a template to a Rack-compatible body.
@@ -127,32 +117,39 @@ module AbstractController
     # Find and renders a template based on the options given.
     # :api: private
     def _render_template(options) #:nodoc:
-      view_context.render(options)
-    end
-
-    # The prefixes used in render "foo" shortcuts.
-    def _prefixes
-      @_prefixes ||= begin
-        parent_prefixes = self.class.parent_prefixes
-        parent_prefixes.dup.unshift(controller_path)
-      end
+      view_renderer.render(view_context, options)
     end
 
     private
 
+    DEFAULT_PROTECTED_INSTANCE_VARIABLES = %w(
+      @_action_name @_response_body @_formats @_prefixes @_config
+      @_view_context_class @_view_renderer @_lookup_context
+    )
+
     # This method should return a hash with assigns.
     # You can overwrite this configuration per controller.
     # :api: public
     def view_assigns
       hash = {}
       variables  = instance_variable_names
-      variables -= protected_instance_variables if respond_to?(:protected_instance_variables)
+      variables -= protected_instance_variables
+      variables -= DEFAULT_PROTECTED_INSTANCE_VARIABLES
       variables.each { |name| hash[name.to_s[1, name.length]] = instance_variable_get(name) }
       hash
     end
 
-    # Normalize options by converting render "foo" to render :action => "foo" and
+    # Normalize args and options.
+    # :api: private
+    def _normalize_render(*args, &block)
+      options = _normalize_args(*args, &block)
+      _normalize_options(options)
+      options
+    end
+
+    # Normalize args by converting render "foo" to render :action => "foo" and
     # render "foo/bar" to render :file => "foo/bar".
+    # :api: plugin
     def _normalize_args(action=nil, options={})
       case action
       when NilClass
@@ -169,6 +166,8 @@ module AbstractController
       options
     end
 
+    # Normalize options.
+    # :api: plugin
     def _normalize_options(options)
       if options[:partial] == true
         options[:partial] = action_name
@@ -182,6 +181,8 @@ module AbstractController
       options
     end
 
+    # Process extra options.
+    # :api: plugin
     def _process_options(options)
     end
   end
diff --git a/actionpack/lib/abstract_controller/view_paths.rb b/actionpack/lib/abstract_controller/view_paths.rb
index cea0f5ad1e..6b7aae8c74 100644
--- a/actionpack/lib/abstract_controller/view_paths.rb
+++ b/actionpack/lib/abstract_controller/view_paths.rb
@@ -11,11 +11,36 @@ module AbstractController
     delegate :find_template, :template_exists?, :view_paths, :formats, :formats=,
              :locale, :locale=, :to => :lookup_context
 
+    module ClassMethods
+      def parent_prefixes
+        @parent_prefixes ||= begin
+          parent_controller = superclass
+          prefixes = []
+
+          until parent_controller.abstract?
+            prefixes << parent_controller.controller_path
+            parent_controller = parent_controller.superclass
+          end
+
+          prefixes
+        end
+      end
+    end
+
+    # The prefixes used in render "foo" shortcuts.
+    def _prefixes
+      @_prefixes ||= begin
+        parent_prefixes = self.class.parent_prefixes
+        parent_prefixes.dup.unshift(controller_path)
+      end
+    end
+
     # LookupContext is the object responsible to hold all information required to lookup
     # templates, i.e. view paths and details. Check ActionView::LookupContext for more
     # information.
     def lookup_context
-      @lookup_context ||= ActionView::LookupContext.new(self.class._view_paths, details_for_lookup)
+      @_lookup_context ||=
+        ActionView::LookupContext.new(self.class._view_paths, details_for_lookup, _prefixes)
     end
 
     def details_for_lookup
@@ -67,4 +92,4 @@ module AbstractController
       end
     end
   end
-end
\ No newline at end of file
+end
diff --git a/actionpack/lib/action_controller.rb b/actionpack/lib/action_controller.rb
index 62cc18b253..eba5e9377b 100644
--- a/actionpack/lib/action_controller.rb
+++ b/actionpack/lib/action_controller.rb
@@ -13,6 +13,7 @@ module ActionController
     autoload :Compatibility
     autoload :ConditionalGet
     autoload :Cookies
+    autoload :DataStreaming
     autoload :Flash
     autoload :ForceSSL
     autoload :Head
@@ -22,6 +23,7 @@ module ActionController
     autoload :ImplicitRender
     autoload :Instrumentation
     autoload :MimeResponds
+    autoload :ParamsWrapper
     autoload :RackDelegation
     autoload :Redirecting
     autoload :Renderers
diff --git a/actionpack/lib/action_controller/base.rb b/actionpack/lib/action_controller/base.rb
index 5f9e082cd3..c03c77cb4a 100644
--- a/actionpack/lib/action_controller/base.rb
+++ b/actionpack/lib/action_controller/base.rb
@@ -200,18 +200,23 @@ module ActionController
       RequestForgeryProtection,
       ForceSSL,
       Streaming,
+      DataStreaming,
       RecordIdentifier,
       HttpAuthentication::Basic::ControllerMethods,
       HttpAuthentication::Digest::ControllerMethods,
       HttpAuthentication::Token::ControllerMethods,
 
+      # Before callbacks should also be executed the earliest as possible, so
+      # also include them at the bottom.
+      AbstractController::Callbacks,
+
       # Add instrumentations hooks at the bottom, to ensure they instrument
       # all the methods properly.
       Instrumentation,
 
-      # Before callbacks should also be executed the earliest as possible, so
-      # also include them at the bottom.
-      AbstractController::Callbacks,
+      # Params wrapper should come before instrumentation so they are
+      # properly showed in logs
+      ParamsWrapper,
 
       # The same with rescue, append it at the end to wrap as much as possible.
       Rescue
diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
index 3fae697cc3..8d813a8e38 100644
--- a/actionpack/lib/action_controller/log_subscriber.rb
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -7,8 +7,10 @@ module ActionController
     def start_processing(event)
       payload = event.payload
       params  = payload[:params].except(*INTERNAL_PARAMS)
+      format  = payload[:format]
+      format  = format.to_s.upcase if format.is_a?(Symbol)
 
-      info "  Processing by #{payload[:controller]}##{payload[:action]} as #{payload[:formats].first.to_s.upcase}"
+      info "  Processing by #{payload[:controller]}##{payload[:action]} as #{format}"
       info "  Parameters: #{params.inspect}" unless params.empty?
     end
 
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index 585bd5e5ab..0133b2ecbc 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -131,7 +131,7 @@ module ActionController
     attr_internal :headers, :response, :request
     delegate :session, :to => "@_request"
 
-    def initialize(*)
+    def initialize
       @_headers = {"Content-Type" => "text/html"}
       @_status = 200
       @_request = nil
diff --git a/actionpack/lib/action_controller/metal/compatibility.rb b/actionpack/lib/action_controller/metal/compatibility.rb
index 006b9fd456..05dca445a4 100644
--- a/actionpack/lib/action_controller/metal/compatibility.rb
+++ b/actionpack/lib/action_controller/metal/compatibility.rb
@@ -18,13 +18,10 @@ module ActionController
         delegate :default_charset=, :to => "ActionDispatch::Response"
       end
 
-      # TODO: Update protected instance variables list
-      config_accessor :protected_instance_variables
-      self.protected_instance_variables = %w(@assigns @performed_redirect @performed_render
-                                             @variables_added @request_origin @url
-                                             @parent_controller @action_name
-                                             @before_filter_chain_aborted @_headers @_params
-                                             @_response)
+      self.protected_instance_variables = %w(
+        @_status @_headers @_params @_env @_response @_request
+        @_view_runtime @_stream @_url_options @_action_has_layout
+      )
 
       def rescue_action(env)
         raise env["action_dispatch.rescue.exception"]
diff --git a/actionpack/lib/action_controller/metal/data_streaming.rb b/actionpack/lib/action_controller/metal/data_streaming.rb
new file mode 100644
index 0000000000..997bc6e958
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/data_streaming.rb
@@ -0,0 +1,145 @@
+require 'active_support/core_ext/file/path'
+
+module ActionController #:nodoc:
+  # Methods for sending arbitrary data and for streaming files to the browser,
+  # instead of rendering.
+  module DataStreaming
+    extend ActiveSupport::Concern
+
+    include ActionController::Rendering
+
+    DEFAULT_SEND_FILE_OPTIONS = {
+      :type         => 'application/octet-stream'.freeze,
+      :disposition  => 'attachment'.freeze,
+    }.freeze
+
+    protected
+      # Sends the file. This uses a server-appropriate method (such as X-Sendfile)
+      # via the Rack::Sendfile middleware. The header to use is set via
+      # config.action_dispatch.x_sendfile_header, and defaults to "X-Sendfile".
+      # Your server can also configure this for you by setting the X-Sendfile-Type header.
+      #
+      # Be careful to sanitize the path parameter if it is coming from a web
+      # page. <tt>send_file(params[:path])</tt> allows a malicious user to
+      # download any file on your server.
+      #
+      # Options:
+      # * <tt>:filename</tt> - suggests a filename for the browser to use.
+      #   Defaults to <tt>File.basename(path)</tt>.
+      # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
+      #   either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
+      # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
+      #   Valid values are 'inline' and 'attachment' (default).
+      # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
+      # * <tt>:url_based_filename</tt> - set to +true+ if you want the browser guess the filename from
+      #   the URL, which is necessary for i18n filenames on certain browsers
+      #   (setting <tt>:filename</tt> overrides this option).
+      #
+      # The default Content-Type and Content-Disposition headers are
+      # set to download arbitrary binary files in as many browsers as
+      # possible.  IE versions 4, 5, 5.5, and 6 are all known to have
+      # a variety of quirks (especially when downloading over SSL).
+      #
+      # Simple download:
+      #
+      #   send_file '/path/to.zip'
+      #
+      # Show a JPEG in the browser:
+      #
+      #   send_file '/path/to.jpeg', :type => 'image/jpeg', :disposition => 'inline'
+      #
+      # Show a 404 page in the browser:
+      #
+      #   send_file '/path/to/404.html', :type => 'text/html; charset=utf-8', :status => 404
+      #
+      # Read about the other Content-* HTTP headers if you'd like to
+      # provide the user with more information (such as Content-Description) in
+      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11.
+      #
+      # Also be aware that the document may be cached by proxies and browsers.
+      # The Pragma and Cache-Control headers declare how the file may be cached
+      # by intermediaries.  They default to require clients to validate with
+      # the server before releasing cached responses.  See
+      # http://www.mnot.net/cache_docs/ for an overview of web caching and
+      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
+      # for the Cache-Control header spec.
+      def send_file(path, options = {}) #:doc:
+        raise MissingFile, "Cannot read file #{path}" unless File.file?(path) and File.readable?(path)
+
+        options[:filename] ||= File.basename(path) unless options[:url_based_filename]
+        send_file_headers! options
+
+        self.status = options[:status] || 200
+        self.content_type = options[:content_type] if options.key?(:content_type)
+        self.response_body = File.open(path, "rb")
+      end
+
+      # Sends the given binary data to the browser. This method is similar to
+      # <tt>render :text => data</tt>, but also allows you to specify whether
+      # the browser should display the response as a file attachment (i.e. in a
+      # download dialog) or as inline data. You may also set the content type,
+      # the apparent file name, and other things.
+      #
+      # Options:
+      # * <tt>:filename</tt> - suggests a filename for the browser to use.
+      # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
+      #   either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
+      # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
+      #   Valid values are 'inline' and 'attachment' (default).
+      # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
+      #
+      # Generic data download:
+      #
+      #   send_data buffer
+      #
+      # Download a dynamically-generated tarball:
+      #
+      #   send_data generate_tgz('dir'), :filename => 'dir.tgz'
+      #
+      # Display an image Active Record in the browser:
+      #
+      #   send_data image.data, :type => image.content_type, :disposition => 'inline'
+      #
+      # See +send_file+ for more information on HTTP Content-* headers and caching.
+      def send_data(data, options = {}) #:doc:
+        send_file_headers! options.dup
+        render options.slice(:status, :content_type).merge(:text => data)
+      end
+
+    private
+      def send_file_headers!(options)
+        options.update(DEFAULT_SEND_FILE_OPTIONS.merge(options))
+        [:type, :disposition].each do |arg|
+          raise ArgumentError, ":#{arg} option required" if options[arg].nil?
+        end
+
+        disposition = options[:disposition]
+        disposition += %(; filename="#{options[:filename]}") if options[:filename]
+
+        content_type = options[:type]
+
+        if content_type.is_a?(Symbol)
+          extension = Mime[content_type]
+          raise ArgumentError, "Unknown MIME type #{options[:type]}" unless extension
+          self.content_type = extension
+        else
+          self.content_type = content_type
+        end
+
+        headers.merge!(
+          'Content-Disposition'       => disposition,
+          'Content-Transfer-Encoding' => 'binary'
+        )
+
+        response.sending_file = true
+
+        # Fix a problem with IE 6.0 on opening downloaded files:
+        # If Cache-Control: no-cache is set (which Rails does by default),
+        # IE removes the file it just downloaded from its cache immediately
+        # after it displays the "open/save" dialog, which means that if you
+        # hit "open" the file isn't there anymore when the application that
+        # is called for handling the download is run, so let's workaround that
+        response.cache_control[:public] ||= false
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/helpers.rb b/actionpack/lib/action_controller/metal/helpers.rb
index 91a88ab68a..75757db564 100644
--- a/actionpack/lib/action_controller/metal/helpers.rb
+++ b/actionpack/lib/action_controller/metal/helpers.rb
@@ -76,35 +76,35 @@ module ActionController
         @helper_proxy ||= ActionView::Base.new.extend(_helpers)
       end
 
-      private
-        # Overwrite modules_for_helpers to accept :all as argument, which loads
-        # all helpers in helpers_path.
-        #
-        # ==== Parameters
-        # * <tt>args</tt> - A list of helpers
-        #
-        # ==== Returns
-        # * <tt>array</tt> - A normalized list of modules for the list of helpers provided.
-        def modules_for_helpers(args)
-          args += all_application_helpers if args.delete(:all)
-          super(args)
-        end
+      # Overwrite modules_for_helpers to accept :all as argument, which loads
+      # all helpers in helpers_path.
+      #
+      # ==== Parameters
+      # * <tt>args</tt> - A list of helpers
+      #
+      # ==== Returns
+      # * <tt>array</tt> - A normalized list of modules for the list of helpers provided.
+      def modules_for_helpers(args)
+        args += all_application_helpers if args.delete(:all)
+        super(args)
+      end
 
-        # Extract helper names from files in <tt>app/helpers/**/*_helper.rb</tt>
-        def all_application_helpers
-          all_helpers_from_path(helpers_path)
+      def all_helpers_from_path(path)
+        helpers = []
+        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
+        helpers.sort!
+        helpers.uniq!
+        helpers
+      end
 
-        def all_helpers_from_path(path)
-          helpers = []
-          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
-          helpers.sort!
-          helpers.uniq!
-          helpers
-        end
+      private
+      # Extract helper names from files in <tt>app/helpers/**/*_helper.rb</tt>
+      def all_application_helpers
+        all_helpers_from_path(helpers_path)
+      end
     end
   end
 end
diff --git a/actionpack/lib/action_controller/metal/implicit_render.rb b/actionpack/lib/action_controller/metal/implicit_render.rb
index 3ec0c4c6a4..e8e465d3ba 100644
--- a/actionpack/lib/action_controller/metal/implicit_render.rb
+++ b/actionpack/lib/action_controller/metal/implicit_render.rb
@@ -1,21 +1,19 @@
 module ActionController
   module ImplicitRender
     def send_action(method, *args)
-      if respond_to?(method, true)
-        ret = super
-        default_render unless response_body
-        ret
-      else
-        default_render
-      end
+      ret = super
+      default_render unless response_body
+      ret
     end
 
     def default_render(*args)
       render(*args)
     end
 
-    def action_method?(action_name)
-      super || template_exists?(action_name.to_s, _prefixes)
+    def method_for_action(action_name)
+      super || if template_exists?(action_name.to_s, _prefixes)
+        "default_render"
+      end
     end
   end
 end
diff --git a/actionpack/lib/action_controller/metal/instrumentation.rb b/actionpack/lib/action_controller/metal/instrumentation.rb
index dc3ea939e6..16cbbce2fb 100644
--- a/actionpack/lib/action_controller/metal/instrumentation.rb
+++ b/actionpack/lib/action_controller/metal/instrumentation.rb
@@ -14,12 +14,12 @@ module ActionController
 
     attr_internal :view_runtime
 
-    def process_action(action, *args)
+    def process_action(*args)
       raw_payload = {
         :controller => self.class.name,
         :action     => self.action_name,
         :params     => request.filtered_parameters,
-        :formats    => request.formats.map(&:to_sym),
+        :format     => request.format.ref,
         :method     => request.method,
         :path       => (request.fullpath rescue "unknown")
       }
diff --git a/actionpack/lib/action_controller/metal/mime_responds.rb b/actionpack/lib/action_controller/metal/mime_responds.rb
index 16d48e4677..f10287afb4 100644
--- a/actionpack/lib/action_controller/metal/mime_responds.rb
+++ b/actionpack/lib/action_controller/metal/mime_responds.rb
@@ -6,6 +6,8 @@ module ActionController #:nodoc:
   module MimeResponds
     extend ActiveSupport::Concern
 
+    include ActionController::ImplicitRender
+
     included do
       class_attribute :responder, :mimes_for_respond_to
       self.responder = ActionController::Responder
diff --git a/actionpack/lib/action_controller/metal/params_wrapper.rb b/actionpack/lib/action_controller/metal/params_wrapper.rb
new file mode 100644
index 0000000000..881af74147
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/params_wrapper.rb
@@ -0,0 +1,224 @@
+require 'active_support/core_ext/class/attribute'
+require 'active_support/core_ext/hash/slice'
+require 'active_support/core_ext/hash/except'
+require 'active_support/core_ext/array/wrap'
+require 'action_dispatch/http/mime_types'
+
+module ActionController
+  # Wraps parameters hash into nested hash. This will allow client to submit
+  # POST request without having to specify a root element in it.
+  #
+  # By default this functionality won't be enabled. You can enable
+  # it globally by setting +ActionController::Base.wrap_parameters+:
+  #
+  #     ActionController::Base.wrap_parameters = [:json]
+  #
+  # You could also turn it on per controller by setting the format array to
+  # non-empty array:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters :format => [:json, :xml]
+  #     end
+  #
+  # If you enable +ParamsWrapper+ for +:json+ format. Instead of having to
+  # send JSON parameters like this:
+  #
+  #     {"user": {"name": "Konata"}}
+  #
+  # You can now just send a parameters like this:
+  #
+  #     {"name": "Konata"}
+  #
+  # And it will be wrapped into a nested hash with the key name matching
+  # controller's name. For example, if you're posting to +UsersController+,
+  # your new +params+ hash will look like this:
+  #
+  #     {"name" => "Konata", "user" => {"name" => "Konata"}}
+  #
+  # You can also specify the key in which the parameters should be wrapped to,
+  # and also the list of attributes it should wrap by using either +:only+ or
+  # +:except+ options like this:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters :person, :only => [:username, :password]
+  #     end
+  #
+  # If you're going to pass the parameters to an +ActiveModel+ object (such as
+  # +User.new(params[:user])+), you might consider passing the model class to
+  # the method instead. The +ParamsWrapper+ will actually try to determine the
+  # list of attribute names from the model and only wrap those attributes:
+  #
+  #     class UsersController < ApplicationController
+  #       wrap_parameters Person
+  #     end
+  #
+  # You still could pass +:only+ and +:except+ to set the list of attributes
+  # you want to wrap.
+  #
+  # By default, if you don't specify the key in which the parameters would be
+  # wrapped to, +ParamsWrapper+ will actually try to determine if there's
+  # a model related to it or not. This controller, for example:
+  #
+  #     class Admin::UsersController < ApplicationController
+  #     end
+  #
+  # will try to check if +Admin::User+ or +User+ model exists, and use it to
+  # determine the wrapper key respectively. If both of the model doesn't exists,
+  # it will then fallback to use +user+ as the key.
+  module ParamsWrapper
+    extend ActiveSupport::Concern
+
+    EXCLUDE_PARAMETERS = %w(authenticity_token _method utf8)
+
+    included do
+      class_attribute :_wrapper_options
+      self._wrapper_options = {:format => []}
+    end
+
+    module ClassMethods
+      # Sets the name of the wrapper key, or the model which +ParamsWrapper+
+      # would use to determine the attribute names from.
+      #
+      # ==== Examples
+      #   wrap_parameters :format => :xml
+      #     # enables the parmeter wrapper for XML format
+      #
+      #   wrap_parameters :person
+      #     # wraps parameters into +params[:person]+ hash
+      #
+      #   wrap_parameters Person
+      #     # wraps parameters by determine the wrapper key from Person class
+      #     (+person+, in this case) and the list of attribute names
+      #
+      #   wrap_parameters :only => [:username, :title]
+      #     # wraps only +:username+ and +:title+ attributes from parameters.
+      #
+      #   wrap_parameters false
+      #     # disable parameters wrapping for this controller altogether.
+      #
+      # ==== Options
+      # * <tt>:format</tt> - The list of formats in which the parameters wrapper
+      #   will be enabled.
+      # * <tt>:only</tt> - The list of attribute names which parameters wrapper
+      #   will wrap into a nested hash.
+      # * <tt>:except</tt> - The list of attribute names which parameters wrapper
+      #   will exclude from a nested hash.
+      def wrap_parameters(name_or_model_or_options, options = {})
+        model = nil
+
+        case name_or_model_or_options
+        when Hash
+          options = name_or_model_or_options
+        when false
+          options = options.merge(:format => [])
+        when Symbol, String
+          options = options.merge(:name => name_or_model_or_options)
+        else
+          model = name_or_model_or_options
+        end
+
+        _set_wrapper_defaults(_wrapper_options.slice(:format).merge(options), model)
+      end
+
+      # Sets the default wrapper key or model which will be used to determine
+      # wrapper key and attribute names. Will be called automatically when the
+      # module is inherited.
+      def inherited(klass)
+        if klass._wrapper_options[:format].present?
+          klass._set_wrapper_defaults(klass._wrapper_options.slice(:format))
+        end
+        super
+      end
+
+      protected
+
+      # Determine the wrapper model from the controller's name. By convention,
+      # this could be done by trying to find the defined model that has the
+      # same singularize name as the controller. For example, +UsersController+
+      # will try to find if the +User+ model exists.
+      def _default_wrap_model
+        model_name = self.name.sub(/Controller$/, '').singularize
+
+        begin
+          model_klass = model_name.constantize
+        rescue NameError => e
+          unscoped_model_name = model_name.split("::", 2).last
+          break if unscoped_model_name == model_name
+          model_name = unscoped_model_name
+        end until model_klass
+
+        model_klass
+      end
+
+      def _set_wrapper_defaults(options, model=nil)
+        options = options.dup
+
+        unless options[:only] || options[:except]
+          model ||= _default_wrap_model
+          if model.respond_to?(:column_names)
+            options[:only] = model.column_names
+          end
+        end
+
+        unless options[:name]
+          model ||= _default_wrap_model
+          options[:name] = model ? model.to_s.demodulize.underscore :
+            controller_name.singularize
+        end
+
+        options[:only]   = Array.wrap(options[:only]).collect(&:to_s)   if options[:only]
+        options[:except] = Array.wrap(options[:except]).collect(&:to_s) if options[:except]
+        options[:format] = Array.wrap(options[:format])
+
+        self._wrapper_options = options
+      end
+    end
+
+    # Performs parameters wrapping upon the request. Will be called automatically
+    # by the metal call stack.
+    def process_action(*args)
+      if _wrapper_enabled?
+        wrapped_hash = _wrap_parameters request.request_parameters
+        wrapped_filtered_hash = _wrap_parameters request.filtered_parameters
+
+        # This will make the wrapped hash accessible from controller and view
+        request.parameters.merge! wrapped_hash
+        request.request_parameters.merge! wrapped_hash
+
+        # This will make the wrapped hash displayed in the log file
+        request.filtered_parameters.merge! wrapped_filtered_hash
+      end
+      super
+    end
+
+    private
+
+      # Returns the wrapper key which will use to stored wrapped parameters.
+      def _wrapper_key
+        _wrapper_options[:name]
+      end
+
+      # Returns the list of enabled formats.
+      def _wrapper_formats
+        _wrapper_options[:format]
+      end
+
+      # Returns the list of parameters which will be selected for wrapped.
+      def _wrap_parameters(parameters)
+        value = if only = _wrapper_options[:only]
+          parameters.slice(*only)
+        else
+          except = _wrapper_options[:except] || []
+          parameters.except(*(except + EXCLUDE_PARAMETERS))
+        end
+
+        { _wrapper_key => value }
+      end
+
+      # Checks if we should perform parameters wrapping.
+      def _wrapper_enabled?
+        ref = request.content_mime_type.try(:ref)
+        _wrapper_formats.include?(ref) && !request.request_parameters[_wrapper_key]
+      end
+  end
+end
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index dfda6618e7..0ad9dbeda9 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -95,17 +95,17 @@ module ActionController
       json = json.to_json(options) unless json.kind_of?(String)
       json = "#{options[:callback]}(#{json})" unless options[:callback].blank?
       self.content_type ||= Mime::JSON
-      self.response_body  = json
+      json
     end
 
     add :js do |js, options|
       self.content_type ||= Mime::JS
-      self.response_body  = js.respond_to?(:to_js) ? js.to_js(options) : js
+      js.respond_to?(:to_js) ? js.to_js(options) : js
     end
 
     add :xml do |xml, options|
       self.content_type ||= Mime::XML
-      self.response_body  = xml.respond_to?(:to_xml) ? xml.to_xml(options) : xml
+      xml.respond_to?(:to_xml) ? xml.to_xml(options) : xml
     end
   end
 end
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
index 32d52c84c4..70fd79bb8b 100644
--- a/actionpack/lib/action_controller/metal/rendering.rb
+++ b/actionpack/lib/action_controller/metal/rendering.rb
@@ -18,6 +18,17 @@ module ActionController
       response_body
     end
 
+    # Overwrite render_to_string because body can now be set to a rack body.
+    def render_to_string(*)
+      if self.response_body = super
+        string = ""
+        response_body.each { |r| string << r }
+        string
+      end
+    ensure
+      self.response_body = nil
+    end
+
     private
 
     # Normalize arguments by catching blocks and setting them on :update.
diff --git a/actionpack/lib/action_controller/metal/responder.rb b/actionpack/lib/action_controller/metal/responder.rb
index 59a3621f72..ebadb29ea7 100644
--- a/actionpack/lib/action_controller/metal/responder.rb
+++ b/actionpack/lib/action_controller/metal/responder.rb
@@ -68,7 +68,7 @@ module ActionController #:nodoc:
   #     respond_with(@project, @task)
   #   end
   #
-  # Giving an array of resources, you ensure that the responder will redirect to
+  # Giving several resources ensures that the responder will redirect to
   # <code>project_task_url</code> instead of <code>task_url</code>.
   #
   # Namespaced and singleton resources require a symbol to be given, as in
@@ -77,6 +77,11 @@ module ActionController #:nodoc:
   #
   #   respond_with(@project, :manager, @task)
   #
+  # Note that if you give an array, it will be treated as a collection,
+  # so the following is not equivalent:
+  #
+  #   respond_with [@project, :manager, @task]
+  #
   # === Custom options
   #
   # <code>respond_with</code> also allow you to pass options that are forwarded
diff --git a/actionpack/lib/action_controller/metal/streaming.rb b/actionpack/lib/action_controller/metal/streaming.rb
index 312dc8eb3e..3892a12407 100644
--- a/actionpack/lib/action_controller/metal/streaming.rb
+++ b/actionpack/lib/action_controller/metal/streaming.rb
@@ -1,145 +1,263 @@
 require 'active_support/core_ext/file/path'
+require 'rack/chunked'
 
 module ActionController #:nodoc:
-  # Methods for sending arbitrary data and for streaming files to the browser,
-  # instead of rendering.
+  # Allows views to be streamed back to the client as they are rendered.
+  #
+  # The default way Rails renders views is by first rendering the template
+  # and then the layout. The response is sent to the client after the whole
+  # template is rendered, all queries are made, and the layout is processed.
+  #
+  # Streaming inverts the rendering flow by rendering the layout first and
+  # streaming each part of the layout as they are processed. This allows the
+  # header of the HTML (which is usually in the layout) to be streamed back
+  # to client very quickly, allowing JavaScripts and stylesheets to be loaded
+  # earlier than usual.
+  #
+  # This approach was introduced in Rails 3.1 and is still improving. Several
+  # Rack middlewares may not work and you need to be careful when streaming.
+  # Those points are going to be addressed soon.
+  #
+  # In order to use streaming, you will need to use a Ruby version that
+  # supports fibers (fibers are supported since version 1.9.2 of the main
+  # Ruby implementation).
+  #
+  # == Examples
+  #
+  # Streaming can be added to a controller easily, all you need to do is
+  # call +stream+ in the controller class:
+  #
+  #   class PostsController
+  #     stream
+  #   end
+  #
+  # The +stream+ method accepts the same options as +before_filter+ and friends:
+  #
+  #   class PostsController
+  #     stream :only => :index
+  #   end
+  #
+  # You can also selectively turn on streaming for specific actions:
+  #
+  #   class PostsController
+  #     def index
+  #       @posts = Post.scoped
+  #       render :stream => true
+  #     end
+  #   end
+  #
+  # == When to use streaming
+  #
+  # Streaming may be considered to be overkill for lightweight actions like
+  # +new+ or +edit+. The real benefit of streaming is on expensive actions
+  # that, for example, do a lot of queries on the database.
+  #
+  # In such actions, you want to delay queries execution as much as you can.
+  # For example, imagine the following +dashboard+ action:
+  #
+  #   def dashboard
+  #     @posts = Post.all
+  #     @pages = Page.all
+  #     @articles = Article.all
+  #   end
+  #
+  # Most of the queries here are happening in the controller. In order to benefit
+  # from streaming you would want to rewrite it as:
+  #
+  #   def dashboard
+  #     # Allow lazy execution of the queries
+  #     @posts = Post.scoped
+  #     @pages = Page.scoped
+  #     @articles = Article.scoped
+  #     render :stream => true
+  #   end
+  #
+  # == Communication between layout and template
+  #
+  # When streaming, rendering happens top-down instead of inside-out.
+  # Rails starts with the layout, and the template is rendered later,
+  # when its +yield+ is reached.
+  #
+  # This means that, if your application currently relies on instance
+  # variables set in the template to be used in the layout, they won't
+  # work once you move to streaming. The proper way to communicate
+  # between layout and template, regardless of whether you use streaming
+  # or not, is by using +content_for+, +provide+ and +yield+.
+  #
+  # Take a simple example where the layout expects the template to tell
+  # which title to use:
+  #
+  #   <html>
+  #     <head><title><%= yield :title %></title></head>
+  #     <body><%= yield %></body>
+  #   </html>
+  #
+  # You would use +content_for+ in your template to specify the title:
+  #
+  #   <%= content_for :title, "Main" %>
+  #   Hello
+  #
+  # And the final result would be:
+  #
+  #   <html>
+  #     <head><title>Main</title></head>
+  #     <body>Hello</body>
+  #   </html>
+  #
+  # However, if +content_for+ is called several times, the final result
+  # would have all calls concatenated. For instance, if we have the following
+  # template:
+  #
+  #   <%= content_for :title, "Main" %>
+  #   Hello
+  #   <%= content_for :title, " page" %>
+  #
+  # The final result would be:
+  #
+  #   <html>
+  #     <head><title>Main page</title></head>
+  #     <body>Hello</body>
+  #   </html>
+  #
+  # This means that, if you have <code>yield :title</code> in your layout
+  # and you want to use streaming, you would have to render the whole template
+  # (and eventually trigger all queries) before streaming the title and all
+  # assets, which kills the purpose of streaming. For this reason Rails 3.1
+  # introduces a new helper called +provide+ that does the same as +content_for+
+  # but tells the layout to stop searching for other entries and continue rendering.
+  #
+  # For instance, the template above using +provide+ would be:
+  #
+  #   <%= provide :title, "Main" %>
+  #   Hello
+  #   <%= content_for :title, " page" %>
+  #
+  # Giving:
+  #
+  #   <html>
+  #     <head><title>Main</title></head>
+  #     <body>Hello</body>
+  #   </html>
+  #
+  # That said, when streaming, you need to properly check your templates
+  # and choose when to use +provide+ and +content_for+.
+  #
+  # == Headers, cookies, session and flash
+  #
+  # When streaming, the HTTP headers are sent to the client right before
+  # it renders the first line. This means that, modifying headers, cookies,
+  # session or flash after the template starts rendering will not propagate
+  # to the client.
+  #
+  # If you try to modify cookies, session or flash, an +ActionDispatch::ClosedError+
+  # will be raised, showing those objects are closed for modification.
+  #
+  # == Middlewares
+  #
+  # Middlewares that need to manipulate the body won't work with streaming.
+  # You should disable those middlewares whenever streaming in development
+  # or production. For instance, +Rack::Bug+ won't work when streaming as it
+  # needs to inject contents in the HTML body.
+  #
+  # Also +Rack::Cache+ won't work with streaming as it does not support
+  # streaming bodies yet. Whenever streaming Cache-Control is automatically
+  # set to "no-cache".
+  #
+  # == Errors
+  #
+  # When it comes to streaming, exceptions get a bit more complicated. This
+  # happens because part of the template was already rendered and streamed to
+  # the client, making it impossible to render a whole exception page.
+  #
+  # Currently, when an exception happens in development or production, Rails
+  # will automatically stream to the client:
+  #
+  #   "><script type="text/javascript">window.location = "/500.html"</script></html>
+  #
+  # The first two characters (">) are required in case the exception happens
+  # while rendering attributes for a given tag. You can check the real cause
+  # for the exception in your logger.
+  #
+  # == Web server support
+  #
+  # Not all web servers support streaming out-of-the-box. You need to check
+  # the instructions for each of them.
+  #
+  # ==== Unicorn
+  #
+  # Unicorn supports streaming but it needs to be configured. For this, you
+  # need to create a config file as follow:
+  #
+  #   # unicorn.config.rb
+  #   listen 3000, :tcp_nopush => false
+  #
+  # And use it on initialization:
+  #
+  #   unicorn_rails --config-file unicorn.config.rb
+  #
+  # You may also want to configure other parameters like <tt>:tcp_nodelay</tt>.
+  # Please check its documentation for more information: http://unicorn.bogomips.org/Unicorn/Configurator.html#method-i-listen
+  #
+  # If you are using Unicorn with Nginx, you may need to tweak Nginx.
+  # Streaming should work out of the box on Rainbows.
+  #
+  # ==== Passenger
+  #
+  # To be described.
+  # 
   module Streaming
     extend ActiveSupport::Concern
 
-    include ActionController::Rendering
+    include AbstractController::Rendering
+    attr_internal :stream
 
-    DEFAULT_SEND_FILE_OPTIONS = {
-      :type         => 'application/octet-stream'.freeze,
-      :disposition  => 'attachment'.freeze,
-    }.freeze
-
-    protected
-      # Sends the file. This uses a server-appropriate method (such as X-Sendfile)
-      # via the Rack::Sendfile middleware. The header to use is set via
-      # config.action_dispatch.x_sendfile_header, and defaults to "X-Sendfile".
-      # Your server can also configure this for you by setting the X-Sendfile-Type header.
-      #
-      # Be careful to sanitize the path parameter if it is coming from a web
-      # page. <tt>send_file(params[:path])</tt> allows a malicious user to
-      # download any file on your server.
-      #
-      # Options:
-      # * <tt>:filename</tt> - suggests a filename for the browser to use.
-      #   Defaults to <tt>File.basename(path)</tt>.
-      # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
-      #   either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
-      # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
-      #   Valid values are 'inline' and 'attachment' (default).
-      # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
-      # * <tt>:url_based_filename</tt> - set to +true+ if you want the browser guess the filename from
-      #   the URL, which is necessary for i18n filenames on certain browsers
-      #   (setting <tt>:filename</tt> overrides this option).
-      #
-      # The default Content-Type and Content-Disposition headers are
-      # set to download arbitrary binary files in as many browsers as
-      # possible.  IE versions 4, 5, 5.5, and 6 are all known to have
-      # a variety of quirks (especially when downloading over SSL).
-      #
-      # Simple download:
-      #
-      #   send_file '/path/to.zip'
-      #
-      # Show a JPEG in the browser:
-      #
-      #   send_file '/path/to.jpeg', :type => 'image/jpeg', :disposition => 'inline'
-      #
-      # Show a 404 page in the browser:
-      #
-      #   send_file '/path/to/404.html', :type => 'text/html; charset=utf-8', :status => 404
-      #
-      # Read about the other Content-* HTTP headers if you'd like to
-      # provide the user with more information (such as Content-Description) in
-      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.11.
-      #
-      # Also be aware that the document may be cached by proxies and browsers.
-      # The Pragma and Cache-Control headers declare how the file may be cached
-      # by intermediaries.  They default to require clients to validate with
-      # the server before releasing cached responses.  See
-      # http://www.mnot.net/cache_docs/ for an overview of web caching and
-      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
-      # for the Cache-Control header spec.
-      def send_file(path, options = {}) #:doc:
-        raise MissingFile, "Cannot read file #{path}" unless File.file?(path) and File.readable?(path)
-
-        options[:filename] ||= File.basename(path) unless options[:url_based_filename]
-        send_file_headers! options
-
-        self.status = options[:status] || 200
-        self.content_type = options[:content_type] if options.key?(:content_type)
-        self.response_body = File.open(path, "rb")
-      end
-
-      # Sends the given binary data to the browser. This method is similar to
-      # <tt>render :text => data</tt>, but also allows you to specify whether
-      # the browser should display the response as a file attachment (i.e. in a
-      # download dialog) or as inline data. You may also set the content type,
-      # the apparent file name, and other things.
-      #
-      # Options:
-      # * <tt>:filename</tt> - suggests a filename for the browser to use.
-      # * <tt>:type</tt> - specifies an HTTP content type. Defaults to 'application/octet-stream'. You can specify
-      #   either a string or a symbol for a registered type register with <tt>Mime::Type.register</tt>, for example :json
-      # * <tt>:disposition</tt> - specifies whether the file will be shown inline or downloaded.
-      #   Valid values are 'inline' and 'attachment' (default).
-      # * <tt>:status</tt> - specifies the status code to send with the response. Defaults to '200 OK'.
-      #
-      # Generic data download:
-      #
-      #   send_data buffer
-      #
-      # Download a dynamically-generated tarball:
-      #
-      #   send_data generate_tgz('dir'), :filename => 'dir.tgz'
-      #
-      # Display an image Active Record in the browser:
-      #
-      #   send_data image.data, :type => image.content_type, :disposition => 'inline'
-      #
-      # See +send_file+ for more information on HTTP Content-* headers and caching.
-      def send_data(data, options = {}) #:doc:
-        send_file_headers! options.dup
-        render options.slice(:status, :content_type).merge(:text => data)
+    module ClassMethods
+      # Render streaming templates. It accepts :only, :except, :if and :unless as options
+      # to specify when to stream, as in ActionController filters.
+      def stream(options={})
+        if defined?(Fiber)
+          before_filter :_stream_filter, options
+        else
+          raise "You cannot use streaming if Fiber is not available."
+        end
       end
+    end
 
-    private
-      def send_file_headers!(options)
-        options.update(DEFAULT_SEND_FILE_OPTIONS.merge(options))
-        [:type, :disposition].each do |arg|
-          raise ArgumentError, ":#{arg} option required" if options[arg].nil?
-        end
+    protected
 
-        disposition = options[:disposition]
-        disposition += %(; filename="#{options[:filename]}") if options[:filename]
+    # Mark following render calls as streaming.
+    def _stream_filter #:nodoc:
+      self.stream = true
+    end
 
-        content_type = options[:type]
+    # Consider the stream option when normalazing options.
+    def _normalize_options(options) #:nodoc:
+      super
+      options[:stream] = self.stream unless options.key?(:stream)
+    end
 
-        if content_type.is_a?(Symbol)
-          extension = Mime[content_type]
-          raise ArgumentError, "Unknown MIME type #{options[:type]}" unless extension
-          self.content_type = extension
+    # Set proper cache control and transfer encoding when streaming
+    def _process_options(options) #:nodoc:
+      super
+      if options[:stream]
+        if env["HTTP_VERSION"] == "HTTP/1.0"
+          options.delete(:stream)
         else
-          self.content_type = content_type
+          headers["Cache-Control"] ||= "no-cache"
+          headers["Transfer-Encoding"] = "chunked"
+          headers.delete("Content-Length")
         end
+      end
+    end
 
-        headers.merge!(
-          'Content-Disposition'       => disposition,
-          'Content-Transfer-Encoding' => 'binary'
-        )
-
-        response.sending_file = true
-
-        # Fix a problem with IE 6.0 on opening downloaded files:
-        # If Cache-Control: no-cache is set (which Rails does by default),
-        # IE removes the file it just downloaded from its cache immediately
-        # after it displays the "open/save" dialog, which means that if you
-        # hit "open" the file isn't there anymore when the application that
-        # is called for handling the download is run, so let's workaround that
-        response.cache_control[:public] ||= false
+    # Call render_to_body if we are streaming instead of usual +render+.
+    def _render_template(options) #:nodoc:
+      if options.delete(:stream)
+        Rack::Chunked::Body.new view_renderer.render_body(view_context, options)
+      else
+        super
       end
+    end
   end
 end
+      
\ No newline at end of file
diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index bc4f8bb9ce..0085f542aa 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -147,7 +147,9 @@ module ActionController
         if value.is_a? Fixnum
           value = value.to_s
         elsif value.is_a? Array
-          value = Result.new(value)
+          value = Result.new(value.map { |v| v.is_a?(String) ? v.dup : v })
+        elsif value.is_a? String
+          value = value.dup
         end
 
         if extra_keys.include?(key.to_sym)
diff --git a/actionpack/lib/action_controller/vendor/html-scanner/html/sanitizer.rb b/actionpack/lib/action_controller/vendor/html-scanner/html/sanitizer.rb
index 09dd08898c..91a97c02ff 100644
--- a/actionpack/lib/action_controller/vendor/html-scanner/html/sanitizer.rb
+++ b/actionpack/lib/action_controller/vendor/html-scanner/html/sanitizer.rb
@@ -33,7 +33,7 @@ module HTML
       result = super
       # strip any comments, and if they have a newline at the end (ie. line with
       # only a comment) strip that too
-      result.gsub!(/<!--(.*?)-->[\n]?/m, "") if result
+      result = result.gsub(/<!--(.*?)-->[\n]?/m, "") if (result && result =~ /<!--(.*?)-->[\n]?/m)
       # Recurse - handle all dirty nested tags
       result == text ? result : sanitize(result, options)
     end
diff --git a/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb b/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb
index 0fe2e6d1a6..1eadfc0390 100644
--- a/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb
+++ b/actionpack/lib/action_controller/vendor/html-scanner/html/selector.rb
@@ -128,6 +128,8 @@ module HTML
   #   (no parent element).
   # * <tt>:empty</tt> -- Match the element only if it has no child elements,
   #   and no text content.
+  # * <tt>:content(string)</tt> -- Match the element only if it has <tt>string</tt>
+  #   as its text content (ignoring leading and trailing whitespace).
   # * <tt>:only-child</tt> -- Match the element if it is the only child (element)
   #   of its parent element.
   # * <tt>:only-of-type</tt> -- Match the element if it is the only child (element)
diff --git a/actionpack/lib/action_dispatch/http/mime_negotiation.rb b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
index 68ba1a81b5..980c658ab7 100644
--- a/actionpack/lib/action_dispatch/http/mime_negotiation.rb
+++ b/actionpack/lib/action_dispatch/http/mime_negotiation.rb
@@ -1,6 +1,13 @@
 module ActionDispatch
   module Http
     module MimeNegotiation
+      extend ActiveSupport::Concern
+
+      included do
+        mattr_accessor :ignore_accept_header
+        self.ignore_accept_header = false
+      end
+
       # The MIME type of the HTTP request, such as Mime::XML.
       #
       # For backward compatibility, the post \format is extracted from the
@@ -42,16 +49,14 @@ module ActionDispatch
         formats.first
       end
 
-      BROWSER_LIKE_ACCEPTS = /,\s*\*\/\*|\*\/\*\s*,/
-
       def formats
-        accept = @env['HTTP_ACCEPT']
-
         @env["action_dispatch.request.formats"] ||=
           if parameters[:format]
             Array(Mime[parameters[:format]])
-          elsif xhr? || (accept && accept !~ BROWSER_LIKE_ACCEPTS)
+          elsif use_accept_header && valid_accept_header
             accepts
+          elsif xhr?
+            [Mime::JS]
           else
             [Mime::HTML]
           end
@@ -87,6 +92,18 @@ module ActionDispatch
 
         order.include?(Mime::ALL) ? formats.first : nil
       end
+
+      protected
+
+      BROWSER_LIKE_ACCEPTS = /,\s*\*\/\*|\*\/\*\s*,/
+
+      def valid_accept_header
+        xhr? || (accept && accept !~ BROWSER_LIKE_ACCEPTS)
+      end
+
+      def use_accept_header
+        !self.class.ignore_accept_header
+      end
     end
   end
 end
diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index f07ac44f7a..ccb866f4f7 100644
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -17,16 +17,17 @@ module ActionDispatch
     include ActionDispatch::Http::Upload
     include ActionDispatch::Http::URL
 
-    LOCALHOST = [/^127\.0\.0\.\d{1,3}$/, "::1", /^0:0:0:0:0:0:0:1(%.*)?$/].freeze
-
-    %w[ AUTH_TYPE GATEWAY_INTERFACE
+    LOCALHOST   = [/^127\.0\.0\.\d{1,3}$/, "::1", /^0:0:0:0:0:0:0:1(%.*)?$/].freeze
+    ENV_METHODS = %w[ AUTH_TYPE GATEWAY_INTERFACE
         PATH_TRANSLATED REMOTE_HOST
         REMOTE_IDENT REMOTE_USER REMOTE_ADDR
         SERVER_NAME SERVER_PROTOCOL
 
         HTTP_ACCEPT HTTP_ACCEPT_CHARSET HTTP_ACCEPT_ENCODING
         HTTP_ACCEPT_LANGUAGE HTTP_CACHE_CONTROL HTTP_FROM
-        HTTP_NEGOTIATE HTTP_PRAGMA ].each do |env|
+        HTTP_NEGOTIATE HTTP_PRAGMA ].freeze
+      
+    ENV_METHODS.each do |env|
       class_eval <<-METHOD, __FILE__, __LINE__ + 1
         def #{env.sub(/^HTTP_/n, '').downcase}
           @env["#{env}"]
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 8e03a7879f..1f4f3ac0da 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -32,24 +32,35 @@ module ActionDispatch # :nodoc:
   #      puts @response.body
   #    end
   #  end
-  class Response < Rack::Response
-    attr_accessor :request, :blank
+  class Response
+    attr_accessor :request, :header, :status
+    attr_writer :sending_file
 
-    attr_writer :header, :sending_file
     alias_method :headers=, :header=
+    alias_method :headers,  :header
+
+    delegate :[], :[]=, :to => :@header
+    delegate :each, :to => :@body
+
+    # Sets the HTTP response's content MIME type. For example, in the controller
+    # you could write this:
+    #
+    #  response.content_type = "text/plain"
+    #
+    # If a character set has been defined for this response (see charset=) then
+    # the character set information will also be included in the content type
+    # information.
+    attr_accessor :charset, :content_type
+
+    CONTENT_TYPE = "Content-Type"
+
+    cattr_accessor(:default_charset) { "utf-8" }
 
     module Setup
       def initialize(status = 200, header = {}, body = [])
-        @writer = lambda { |x| @body << x }
-        @block = nil
-        @length = 0
+        self.body, self.header, self.status = body, header, status
 
-        @header = header
-        self.body, self.status = body, status
-
-        @cookie = []
         @sending_file = false
-
         @blank = false
 
         if content_type = self["Content-Type"]
@@ -62,6 +73,7 @@ module ActionDispatch # :nodoc:
       end
     end
 
+    include Rack::Response::Helpers
     include Setup
     include ActionDispatch::Http::Cache::Response
 
@@ -106,13 +118,29 @@ module ActionDispatch # :nodoc:
 
     def body=(body)
       @blank = true if body == EMPTY
-      @body = body.respond_to?(:to_str) ? [body] : body
+
+      # Explicitly check for strings. This is *wrong* theoretically
+      # but if we don't check this, the performance on string bodies
+      # is bad on Ruby 1.8 (because strings responds to each then).
+      @body = if body.respond_to?(:to_str) || !body.respond_to?(:each)
+        [body]
+      else
+        body
+      end
     end
 
     def body_parts
       @body
     end
 
+    def set_cookie(key, value)
+      ::Rack::Utils.set_cookie_header!(header, key, value)
+    end
+
+    def delete_cookie(key, value={})
+      ::Rack::Utils.delete_cookie_header!(header, key, value)
+    end
+
     def location
       headers['Location']
     end
@@ -122,46 +150,21 @@ module ActionDispatch # :nodoc:
       headers['Location'] = url
     end
 
-    # Sets the HTTP response's content MIME type. For example, in the controller
-    # you could write this:
-    #
-    #  response.content_type = "text/plain"
-    #
-    # If a character set has been defined for this response (see charset=) then
-    # the character set information will also be included in the content type
-    # information.
-    attr_accessor :charset, :content_type
-
-    CONTENT_TYPE = "Content-Type"
-
-    cattr_accessor(:default_charset) { "utf-8" }
-
     def to_a
       assign_default_content_type_and_charset!
       handle_conditional_get!
-      self["Set-Cookie"] = self["Set-Cookie"].join("\n") if self["Set-Cookie"].respond_to?(:join)
-      super
-    end
 
-    alias prepare! to_a
+      @header["Set-Cookie"] = @header["Set-Cookie"].join("\n") if @header["Set-Cookie"].respond_to?(:join)
 
-    def each(&callback)
-      if @body.respond_to?(:call)
-        @writer = lambda { |x| callback.call(x) }
-        @body.call(self, self)
+      if [204, 304].include?(@status)
+        @header.delete "Content-Type"
+        [@status, @header, []]
       else
-        @body.each { |part| callback.call(part.to_s) }
+        [@status, @header, self]
       end
-
-      @writer = callback
-      @block.call(self) if @block
-    end
-
-    def write(str)
-      str = str.to_s
-      @writer.call str
-      str
     end
+    alias prepare! to_a
+    alias to_ary   to_a # For implicit splat on 1.9.2
 
     # Returns the response cookies, converted to a Hash of (name => value) pairs
     #
@@ -180,18 +183,18 @@ module ActionDispatch # :nodoc:
       cookies
     end
 
-    private
-      def assign_default_content_type_and_charset!
-        return if headers[CONTENT_TYPE].present?
+  private
 
-        @content_type ||= Mime::HTML
-        @charset      ||= self.class.default_charset
+    def assign_default_content_type_and_charset!
+      return if headers[CONTENT_TYPE].present?
 
-        type = @content_type.to_s.dup
-        type << "; charset=#{@charset}" unless @sending_file
+      @content_type ||= Mime::HTML
+      @charset      ||= self.class.default_charset
 
-        headers[CONTENT_TYPE] = type
-      end
+      type = @content_type.to_s.dup
+      type << "; charset=#{@charset}" unless @sending_file
 
+      headers[CONTENT_TYPE] = type
+    end
   end
 end
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index ac0fd9607d..d9c07d6ca3 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -165,7 +165,7 @@ module ActionDispatch
       # such as 2 to catch <tt>["www"]</tt> instead of <tt>"www.rubyonrails"</tt>
       # in "www.rubyonrails.co.uk".
       def subdomain(tld_length = @@tld_length)
-        subdomains(tld_length)
+        subdomains(tld_length).join(".")
       end
     end
   end
diff --git a/actionpack/lib/action_dispatch/middleware/flash.rb b/actionpack/lib/action_dispatch/middleware/flash.rb
index 027ff7f8ac..2adbce031b 100644
--- a/actionpack/lib/action_dispatch/middleware/flash.rb
+++ b/actionpack/lib/action_dispatch/middleware/flash.rb
@@ -4,7 +4,7 @@ module ActionDispatch
     # read a notice you put there or <tt>flash["notice"] = "hello"</tt>
     # to put a new one.
     def flash
-      @env['action_dispatch.request.flash_hash'] ||= (session["flash"] || Flash::FlashHash.new)
+      @env[Flash::KEY] ||= (session["flash"] || Flash::FlashHash.new)
     end
   end
 
@@ -40,18 +40,16 @@ module ActionDispatch
   #
   # See docs on the FlashHash class for more details about the flash.
   class Flash
+    KEY = 'action_dispatch.request.flash_hash'.freeze
+
     class FlashNow #:nodoc:
+      attr_accessor :flash
+
       def initialize(flash)
         @flash = flash
-        @closed = false
       end
 
-      attr_reader :closed
-      alias :closed? :closed
-      def close!; @closed = true end
-
       def []=(k, v)
-        raise ClosedError, :flash if closed?
         @flash[k] = v
         @flash.discard(k)
         v
@@ -79,11 +77,16 @@ module ActionDispatch
         @used    = Set.new
         @closed  = false
         @flashes = {}
+        @now     = nil
       end
 
-      attr_reader :closed
-      alias :closed? :closed
-      def close!; @closed = true end
+      def initialize_copy(other)
+        if other.now_is_loaded?
+          @now = other.now.dup
+          @now.flash = self
+        end
+        super
+      end
 
       def []=(k, v) #:nodoc:
         raise ClosedError, :flash if closed?
@@ -152,6 +155,10 @@ module ActionDispatch
         @now ||= FlashNow.new(self)
       end
 
+      attr_reader :closed
+      alias :closed? :closed
+      def close!; @closed = true; end
+
       # Keeps either the entire current flash or a specific flash entry available for the next action:
       #
       #    flash.keep            # keeps the entire flash
@@ -205,7 +212,12 @@ module ActionDispatch
         self[:notice] = message
       end
 
-      private
+      protected
+
+        def now_is_loaded?
+          !!@now
+        end
+
         # Used internally by the <tt>keep</tt> and <tt>discard</tt> methods
         #     use()               # marks the entire flash as used
         #     use('msg')          # marks the "msg" entry as used
@@ -231,13 +243,18 @@ module ActionDispatch
       @app.call(env)
     ensure
       session    = env['rack.session'] || {}
-      flash_hash = env['action_dispatch.request.flash_hash']
+      flash_hash = env[KEY]
 
       if flash_hash
-       if !flash_hash.empty? || session.key?('flash')
-        session["flash"] = flash_hash
-       end
-       flash_hash.close!
+        if !flash_hash.empty? || session.key?('flash')
+          session["flash"] = flash_hash
+          new_hash = flash_hash.dup
+        else
+          new_hash = flash_hash
+        end
+
+        env[KEY] = new_hash
+        new_hash.close!
       end
 
       if session.key?('flash') && session['flash'].empty?
diff --git a/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb b/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
index 9c9ccc62f5..8ebf870b95 100644
--- a/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
+++ b/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb
@@ -59,7 +59,7 @@ module ActionDispatch
       end
 
       def set_session(env, sid, session_data, options)
-        persistent_session_id!(session_data, sid)
+        session_data.merge("session_id" => sid)
       end
 
       def set_cookie(env, session_id, cookie)
diff --git a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
index dbe3206808..c17c746096 100644
--- a/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/show_exceptions.rb
@@ -50,7 +50,7 @@ module ActionDispatch
         # Only this middleware cares about RoutingError. So, let's just raise
         # it here.
         if headers['X-Cascade'] == 'pass'
-           raise ActionController::RoutingError, "No route matches #{env['PATH_INFO'].inspect}"
+           raise ActionController::RoutingError, "No route matches [#{env['REQUEST_METHOD']}] #{env['PATH_INFO'].inspect}"
         end
       rescue Exception => exception
         raise exception if env['action_dispatch.show_exceptions'] == false
@@ -116,7 +116,7 @@ module ActionDispatch
       end
 
       def render(status, body)
-        [status, {'Content-Type' => 'text/html', 'Content-Length' => body.bytesize.to_s}, [body]]
+        [status, {'Content-Type' => "text/html; charset=#{Response.default_charset}", 'Content-Length' => body.bytesize.to_s}, [body]]
       end
 
       def public_path
diff --git a/actionpack/lib/action_dispatch/middleware/static.rb b/actionpack/lib/action_dispatch/middleware/static.rb
index 348f7b86b8..404943d720 100644
--- a/actionpack/lib/action_dispatch/middleware/static.rb
+++ b/actionpack/lib/action_dispatch/middleware/static.rb
@@ -2,10 +2,10 @@ require 'rack/utils'
 
 module ActionDispatch
   class FileHandler
-    def initialize(root)
+    def initialize(root, cache_control)
       @root          = root.chomp('/')
       @compiled_root = /^#{Regexp.escape(root)}/
-      @file_server   = ::Rack::File.new(@root)
+      @file_server   = ::Rack::File.new(@root, cache_control)
     end
 
     def match?(path)
@@ -35,18 +35,15 @@ module ActionDispatch
   end
 
   class Static
-    FILE_METHODS = %w(GET HEAD).freeze
-
-    def initialize(app, path)
+    def initialize(app, path, cache_control=nil)
       @app = app
-      @file_handler = FileHandler.new(path)
+      @file_handler = FileHandler.new(path, cache_control)
     end
 
     def call(env)
-      path   = env['PATH_INFO'].chomp('/')
-      method = env['REQUEST_METHOD']
-
-      if FILE_METHODS.include?(method)
+      case env['REQUEST_METHOD']
+      when 'GET', 'HEAD'
+        path = env['PATH_INFO'].chomp('/')
         if match = @file_handler.match?(path)
           env["PATH_INFO"] = match
           return @file_handler.call(env)
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb
index 97f7cf0bbe..0c5bafa666 100644
--- a/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb
@@ -24,7 +24,7 @@
 <div id="session_dump" style="display:none"><pre><%= debug_hash @request.session %></pre></div>
 
 <p><a href="#" onclick="document.getElementById('env_dump').style.display='block'; return false;">Show env dump</a></p>
-<div id="env_dump" style="display:none"><pre><%= debug_hash @request.env %></pre></div>
+<div id="env_dump" style="display:none"><pre><%= debug_hash @request.env.slice(*@request.class::ENV_METHODS) %></pre></div>
 
 
 <h2 style="margin-top: 30px">Response</h2>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb
index 2099fd069a..4b9d3141d5 100644
--- a/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb
@@ -1,7 +1,7 @@
 <h1>
   <%=h @exception.class.to_s %>
   <% if @request.parameters['controller'] %>
-    in <%=h @request.parameters['controller'].classify.pluralize %>Controller<% if @request.parameters['action'] %>#<%=h @request.parameters['action'] %><% end %>
+    in <%=h @request.parameters['controller'].camelize %>Controller<% if @request.parameters['action'] %>#<%=h @request.parameters['action'] %><% end %>
   <% end %>
 </h1>
 <pre><%=h @exception.message %></pre>
diff --git a/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb b/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
index 6c32fb17b8..6e71fd7ddc 100644
--- a/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
+++ b/actionpack/lib/action_dispatch/middleware/templates/rescues/layout.erb
@@ -1,11 +1,13 @@
-<html xmlns="http://www.w3.org/1999/xhtml">
+<!DOCTYPE html>
+<html lang="en">
 <head>
+  <meta charset="utf-8" />
   <title>Action Controller: Exception caught</title>
   <style>
     body { background-color: #fff; color: #333; }
 
     body, p, ol, ul, td {
-      font-family: verdana, arial, helvetica, sans-serif;
+      font-family: helvetica, verdana, arial, sans-serif;
       font-size:   13px;
       line-height: 18px;
     }
diff --git a/actionpack/lib/action_dispatch/railtie.rb b/actionpack/lib/action_dispatch/railtie.rb
index 0a3bd5fe40..f51cc3711b 100644
--- a/actionpack/lib/action_dispatch/railtie.rb
+++ b/actionpack/lib/action_dispatch/railtie.rb
@@ -9,10 +9,12 @@ module ActionDispatch
     config.action_dispatch.show_exceptions = true
     config.action_dispatch.best_standards_support = true
     config.action_dispatch.tld_length = 1
+    config.action_dispatch.ignore_accept_header = false
     config.action_dispatch.rack_cache = {:metastore => "rails:/", :entitystore => "rails:/", :verbose => true}
 
     initializer "action_dispatch.configure" do |app|
       ActionDispatch::Http::URL.tld_length = app.config.action_dispatch.tld_length
+      ActionDispatch::Request.ignore_accept_header = app.config.action_dispatch.ignore_accept_header
     end
   end
 end
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index b28f6c2297..97e8ccc9a5 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -3,6 +3,7 @@ require 'forwardable'
 require 'active_support/core_ext/object/blank'
 require 'active_support/core_ext/object/to_query'
 require 'active_support/core_ext/hash/slice'
+require 'active_support/core_ext/module/remove_method'
 
 module ActionDispatch
   module Routing
@@ -160,7 +161,7 @@ module ActionDispatch
 
             # We use module_eval to avoid leaks
             @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
-              remove_method :#{selector} if method_defined?(:#{selector})
+              remove_possible_method :#{selector}
               def #{selector}(*args)
                 options = args.extract_options!
 
@@ -194,7 +195,7 @@ module ActionDispatch
             hash_access_method = hash_access_name(name, kind)
 
             @module.module_eval <<-END_EVAL, __FILE__, __LINE__ + 1
-              remove_method :#{selector} if method_defined?(:#{selector})
+              remove_possible_method :#{selector}
               def #{selector}(*args)
                 url_for(#{hash_access_method}(*args))
               end
@@ -240,6 +241,11 @@ module ActionDispatch
       end
 
       def eval_block(block)
+        if block.arity == 1
+          raise "You are using the old router DSL which has been removed in Rails 3.1. " <<
+            "Please check how to update your routes file at: http://www.engineyard.com/blog/2010/the-lowdown-on-routes-in-rails-3/ " <<
+            "or add the rails_legacy_mapper gem to your Gemfile"
+        end
         mapper = Mapper.new(self)
         if default_scope
           mapper.with_default_scope(default_scope, &block)
@@ -275,8 +281,7 @@ module ActionDispatch
       module MountedHelpers
       end
 
-      def mounted_helpers(name = :main_app)
-        define_mounted_helper(name) if name
+      def mounted_helpers
         MountedHelpers
       end
 
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
index 8a04cfa886..3335742d47 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -42,7 +42,7 @@ module ActionDispatch
         elsif type.is_a?(Symbol) && @response.response_code == Rack::Utils::SYMBOL_TO_STATUS_CODE[type]
           assert_block("") { true } # to count the assertion
         else
-          assert_block(build_message(message, "Expected response to be a <?>, but was <?>", type, @response.response_code)) { false }
+          flunk(build_message(message, "Expected response to be a <?>, but was <?>", type, @response.response_code))
         end
       end
 
diff --git a/actionpack/lib/action_pack/version.rb b/actionpack/lib/action_pack/version.rb
index 170ceb299a..584e5c3791 100644
--- a/actionpack/lib/action_pack/version.rb
+++ b/actionpack/lib/action_pack/version.rb
@@ -3,7 +3,7 @@ module ActionPack
     MAJOR = 3
     MINOR = 1
     TINY  = 0
-    PRE   = "beta"
+    PRE   = "beta1"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end
diff --git a/actionpack/lib/action_view.rb b/actionpack/lib/action_view.rb
index 4547aceb28..92b6f7c770 100644
--- a/actionpack/lib/action_view.rb
+++ b/actionpack/lib/action_view.rb
@@ -34,13 +34,12 @@ module ActionView
     autoload :Context
     autoload :Helpers
     autoload :LookupContext
-    autoload :Partials
     autoload :PathSet
-    autoload :Rendering
     autoload :Template
     autoload :TestCase
 
     autoload_under "renderer" do
+      autoload :Renderer
       autoload :AbstractRenderer
       autoload :PartialRenderer
       autoload :TemplateRenderer
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 9e8a3c51a3..c98110353f 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -131,12 +131,17 @@ module ActionView #:nodoc:
   #
   # More builder documentation can be found at http://builder.rubyforge.org.
   class Base
-    include Helpers, Rendering, Partials, ::ERB::Util, Context
+    include Helpers, ::ERB::Util, Context
 
     # Specify the proc used to decorate input tags that refer to attributes with errors.
     cattr_accessor :field_error_proc
     @@field_error_proc = Proc.new{ |html_tag, instance| "<div class=\"field_with_errors\">#{html_tag}</div>".html_safe }
 
+    # How to complete the streaming when an exception occurs.
+    # This is our best guess: first try to close the attribute, then the tag.
+    cattr_accessor :streaming_completion_on_exception
+    @@streaming_completion_on_exception = %("><script type="text/javascript">window.location = "/500.html"</script></html>)
+
     class_attribute :helpers
     class_attribute :_routes
 
@@ -151,56 +156,61 @@ module ActionView #:nodoc:
       def cache_template_loading=(value)
         ActionView::Resolver.caching = value
       end
-    end
-
-    attr_accessor :_template, :_view_flow
-    attr_internal :request, :controller, :config, :assigns, :lookup_context
-
-    delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, :to => :lookup_context
 
-    delegate :request_forgery_protection_token, :params, :session, :cookies, :response, :headers,
-             :flash, :action_name, :controller_name, :to => :controller
+      def process_view_paths(value)
+        value.is_a?(PathSet) ?
+          value.dup : ActionView::PathSet.new(Array.wrap(value))
+      end
 
-    delegate :logger, :to => :controller, :allow_nil => true
+      def xss_safe? #:nodoc:
+        true
+      end
 
-    def self.xss_safe? #:nodoc:
-      true
+      # This method receives routes and helpers from the controller
+      # and return a subclass ready to be used as view context.
+      def prepare(routes, helpers) #:nodoc:
+        Class.new(self) do
+          if routes
+            include routes.url_helpers
+            include routes.mounted_helpers
+          end
+
+          if helpers
+            include helpers
+            self.helpers = helpers
+          end
+        end
+      end
     end
 
-    def self.process_view_paths(value)
-      value.is_a?(PathSet) ?
-        value.dup : ActionView::PathSet.new(Array.wrap(value))
-    end
+    attr_accessor :view_renderer
+    attr_internal :config, :assigns
+
+    delegate :lookup_context, :to => :view_renderer
+    delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, :to => :lookup_context
 
     def assign(new_assigns) # :nodoc:
       @_assigns = new_assigns.each { |key, value| instance_variable_set("@#{key}", value) }
     end
 
-    def initialize(lookup_context = nil, assigns_for_first_render = {}, controller = nil, formats = nil) #:nodoc:
-      assign(assigns_for_first_render)
-      self.helpers = Module.new unless self.class.helpers
-
+    def initialize(context = nil, assigns = {}, controller = nil, formats = nil) #:nodoc:
       @_config = {}
-      @_virtual_path = nil
-      @_view_flow = OutputFlow.new
-      @output_buffer = nil
 
-      if @_controller = controller
-        @_request = controller.request if controller.respond_to?(:request)
-        @_config  = controller.config.inheritable_copy if controller.respond_to?(:config)
+      # Handle all these for backwards compatibility.
+      # TODO Provide a new API for AV::Base and deprecate this one.
+      if context.is_a?(ActionView::Renderer)
+        @view_renderer = context
+      elsif
+        lookup_context = context.is_a?(ActionView::LookupContext) ?
+          context : ActionView::LookupContext.new(context)
+        lookup_context.formats  = formats if formats
+        lookup_context.prefixes = controller._prefixes if controller
+        @view_renderer = ActionView::Renderer.new(lookup_context)
       end
 
-      @_lookup_context = lookup_context.is_a?(ActionView::LookupContext) ?
-        lookup_context : ActionView::LookupContext.new(lookup_context)
-      @_lookup_context.formats = formats if formats
-    end
-
-    def controller_path
-      @controller_path ||= controller && controller.controller_path
-    end
-
-    def controller_prefixes
-      @controller_prefixes ||= controller && controller._prefixes
+      assign(assigns)
+      assign_controller(controller)
+      _prepare_context
     end
 
     ActiveSupport.run_load_hooks(:action_view, self)
diff --git a/actionpack/lib/action_view/context.rb b/actionpack/lib/action_view/context.rb
index 39d88333e8..083856b2ca 100644
--- a/actionpack/lib/action_view/context.rb
+++ b/actionpack/lib/action_view/context.rb
@@ -2,38 +2,35 @@ module ActionView
   module CompiledTemplates #:nodoc:
     # holds compiled template code
   end
+
   # = Action View Context
   #
   # Action View contexts are supplied to Action Controller to render template.
   # The default Action View context is ActionView::Base.
   #
-  # In order to work with ActionController, a Context must implement:
-  #
-  # Context#render_partial[options]
-  #   - responsible for setting options[:_template]
-  #   - Returns String with the rendered partial
-  #   options<Hash>:: see _render_partial in ActionView::Base
-  # Context#render_template[template, layout, options, partial]
-  #   - Returns String with the rendered template
-  #   template<ActionView::Template>:: The template to render
-  #   layout<ActionView::Template>:: The layout to render around the template
-  #   options<Hash>:: See _render_template_with_layout in ActionView::Base
-  #   partial<Boolean>:: Whether or not the template to render is a partial
-  #
-  # An Action View context can also mix in Action View's helpers. In order to
-  # mix in helpers, a context must implement:
-  #
-  # Context#controller
-  # - Returns an instance of AbstractController
-  #
-  # In any case, a context must mix in ActionView::Context, which stores compiled
-  # template and provides the output buffer.
+  # In order to work with ActionController, a Context must just include this module.
+  # The initialization of the variables used by the context (@output_buffer, @view_flow,
+  # and @virtual_path) is responsibility of the object that includes this module
+  # (although you can call _prepare_context defined below).
   module Context
     include CompiledTemplates
-    attr_accessor :output_buffer
+    attr_accessor :output_buffer, :view_flow
+
+    # Prepares the context by setting the appropriate instance variables.
+    # :api: plugin
+    def _prepare_context
+      @view_flow     = OutputFlow.new
+      @output_buffer = nil
+      @virtual_path  = nil
+    end
 
-    def convert_to_model(object)
-      object.respond_to?(:to_model) ? object.to_model : object
+    # Encapsulates the interaction with the view flow so it
+    # returns the correct buffer on yield. This is usually
+    # overwriten by helpers to add more behavior.
+    # :api: plugin
+    def _layout_for(name=nil)
+      name ||= :layout
+      view_flow.get(name).html_safe
     end
   end
 end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/flows.rb b/actionpack/lib/action_view/flows.rb
index 386a06511f..a8f740713f 100644
--- a/actionpack/lib/action_view/flows.rb
+++ b/actionpack/lib/action_view/flows.rb
@@ -34,7 +34,7 @@ module ActionView
       @view    = view
       @parent  = nil
       @child   = view.output_buffer
-      @content = view._view_flow.content
+      @content = view.view_flow.content
       @fiber   = fiber
       @root    = Fiber.current.object_id
     end
diff --git a/actionpack/lib/action_view/helpers.rb b/actionpack/lib/action_view/helpers.rb
index 205116f610..78a68db282 100644
--- a/actionpack/lib/action_view/helpers.rb
+++ b/actionpack/lib/action_view/helpers.rb
@@ -9,6 +9,7 @@ module ActionView #:nodoc:
     autoload :AtomFeedHelper
     autoload :CacheHelper
     autoload :CaptureHelper
+    autoload :ControllerHelper
     autoload :CsrfHelper
     autoload :DateHelper
     autoload :DebugHelper
@@ -19,6 +20,7 @@ module ActionView #:nodoc:
     autoload :NumberHelper
     autoload :OutputSafetyHelper
     autoload :RecordTagHelper
+    autoload :RenderingHelper
     autoload :SanitizeHelper
     autoload :SprocketsHelper
     autoload :TagHelper
@@ -38,6 +40,7 @@ module ActionView #:nodoc:
     include AtomFeedHelper
     include CacheHelper
     include CaptureHelper
+    include ControllerHelper
     include CsrfHelper
     include DateHelper
     include DebugHelper
@@ -48,6 +51,7 @@ module ActionView #:nodoc:
     include NumberHelper
     include OutputSafetyHelper
     include RecordTagHelper
+    include RenderingHelper
     include SanitizeHelper
     include SprocketsHelper
     include TagHelper
diff --git a/actionpack/lib/action_view/helpers/asset_paths.rb b/actionpack/lib/action_view/helpers/asset_paths.rb
new file mode 100644
index 0000000000..958f0e0a10
--- /dev/null
+++ b/actionpack/lib/action_view/helpers/asset_paths.rb
@@ -0,0 +1,79 @@
+require 'active_support/core_ext/file'
+require 'action_view/helpers/asset_paths'
+
+module ActionView
+  module Helpers
+
+    class AssetPaths #:nodoc:
+      attr_reader :config, :controller
+
+      def initialize(config, controller)
+        @config = config
+        @controller = controller
+      end
+
+      # Add the extension +ext+ if not present. Return full or scheme-relative URLs otherwise untouched.
+      # Prefix with <tt>/dir/</tt> if lacking a leading +/+. Account for relative URL
+      # roots. Rewrite the asset path for cache-busting asset ids. Include
+      # asset host, if configured, with the correct request protocol.
+      def compute_public_path(source, dir, ext = nil, include_host = true)
+        source = source.to_s
+        return source if is_uri?(source)
+
+        source = rewrite_extension(source, dir, ext) if ext
+        source = rewrite_asset_path(source, dir)
+
+        if controller && include_host
+          has_request = controller.respond_to?(:request)
+          source = rewrite_host_and_protocol(source, has_request)
+        end
+
+        source
+      end
+
+      def is_uri?(path)
+        path =~ %r{^[-a-z]+://|^cid:|^//}
+      end
+
+    private
+
+      def rewrite_extension(source, dir, ext)
+        raise NotImplementedError
+      end
+
+      def rewrite_asset_path(source, path = nil)
+        raise NotImplementedError
+      end
+
+      def rewrite_host_and_protocol(source, has_request)
+        host = compute_asset_host(source)
+        if has_request && host && !is_uri?(host)
+          host = "#{controller.request.protocol}#{host}"
+        end
+        "#{host}#{source}"
+      end
+
+      # Pick an asset host for this source. Returns +nil+ if no host is set,
+      # the host if no wildcard is set, the host interpolated with the
+      # numbers 0-3 if it contains <tt>%d</tt> (the number is the source hash mod 4),
+      # or the value returned from invoking the proc if it's a proc or the value from
+      # invoking call if it's an object responding to call.
+      def compute_asset_host(source)
+        if host = config.asset_host
+          if host.is_a?(Proc) || host.respond_to?(:call)
+            case host.is_a?(Proc) ? host.arity : host.method(:call).arity
+            when 2
+              request = controller.respond_to?(:request) && controller.request
+              host.call(source, request)
+            else
+              host.call(source)
+            end
+          else
+            (host =~ /%d/) ? host % (source.hash % 4) : host
+          end
+        end
+      end
+    end
+
+  end
+end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helper.rb b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
index f6b2d4f3f4..9bc847a1ab 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helper.rb
@@ -57,7 +57,7 @@ module ActionView
     # +asset_host+ to a proc like this:
     #
     #   ActionController::Base.asset_host = Proc.new { |source|
-    #     "http://assets#{source.hash % 2 + 1}.example.com"
+    #     "http://assets#{Digest::MD5.hexdigest(source).to_i(16) % 2 + 1}.example.com"
     #   }
     #   image_tag("rails.png")
     #   # => <img alt="Rails" src="http://assets1.example.com/images/rails.png?1230601161" />
@@ -268,13 +268,17 @@ module ActionView
       #   image_path("edit.png")                                     # => "/images/edit.png"
       #   image_path("icons/edit.png")                               # => "/images/icons/edit.png"
       #   image_path("/icons/edit.png")                              # => "/icons/edit.png"
-      #   image_path("http://www.railsapplication.com/img/edit.png") # => "http://www.railsapplication.com/img/edit.png"
+      #   image_path("http://www.example.com/img/edit.png")          # => "http://www.example.com/img/edit.png"
       #
       # If you have images as application resources this method may conflict with their named routes.
       # The alias +path_to_image+ is provided to avoid that. Rails uses the alias internally, and
       # plugin authors are encouraged to do so.
       def image_path(source)
-        asset_paths.compute_public_path(source, 'images')
+        if config.use_sprockets
+          asset_path(source)
+        else
+          asset_paths.compute_public_path(source, 'images')
+        end
       end
       alias_method :path_to_image, :image_path # aliased to avoid conflicts with an image_path named route
 
@@ -287,9 +291,13 @@ module ActionView
       #   video_path("hd.avi")                                        # => /videos/hd.avi
       #   video_path("trailers/hd.avi")                               # => /videos/trailers/hd.avi
       #   video_path("/trailers/hd.avi")                              # => /trailers/hd.avi
-      #   video_path("http://www.railsapplication.com/vid/hd.avi") # => http://www.railsapplication.com/vid/hd.avi
+      #   video_path("http://www.example.com/vid/hd.avi")             # => http://www.example.com/vid/hd.avi
       def video_path(source)
-        asset_paths.compute_public_path(source, 'videos')
+        if config.use_sprockets
+          asset_path(source)
+        else
+          asset_paths.compute_public_path(source, 'videos')
+        end
       end
       alias_method :path_to_video, :video_path # aliased to avoid conflicts with a video_path named route
 
@@ -302,9 +310,13 @@ module ActionView
       #   audio_path("horse.wav")                                        # => /audios/horse.wav
       #   audio_path("sounds/horse.wav")                                 # => /audios/sounds/horse.wav
       #   audio_path("/sounds/horse.wav")                                # => /sounds/horse.wav
-      #   audio_path("http://www.railsapplication.com/sounds/horse.wav") # => http://www.railsapplication.com/sounds/horse.wav
+      #   audio_path("http://www.example.com/sounds/horse.wav")          # => http://www.example.com/sounds/horse.wav
       def audio_path(source)
-        asset_paths.compute_public_path(source, 'audios')
+        if config.use_sprockets
+          asset_path(source)
+        else
+          asset_paths.compute_public_path(source, 'audios')
+        end
       end
       alias_method :path_to_audio, :audio_path # aliased to avoid conflicts with an audio_path named route
 
@@ -434,7 +446,7 @@ module ActionView
       private
 
         def asset_paths
-          @asset_paths ||= AssetPaths.new(config, controller)
+          @asset_paths ||= AssetTagHelper::AssetPaths.new(config, controller)
         end
     end
   end
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
index 52eb43a1cd..e4662a2919 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
@@ -8,9 +8,11 @@ module ActionView
     module AssetTagHelper
 
       class AssetIncludeTag
-        attr_reader :config, :asset_paths
+        include TagHelper
 
+        attr_reader :config, :asset_paths
         class_attribute :expansions
+
         def self.inherited(base)
           base.expansions = { }
         end
@@ -56,7 +58,6 @@ module ActionView
           end
         end
 
-
         private
 
           def path_to_asset(source, include_host = true)
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_paths.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_paths.rb
index 1e00fd996b..cd0f8c8878 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_paths.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_paths.rb
@@ -1,10 +1,11 @@
 require 'active_support/core_ext/file'
+require 'action_view/helpers/asset_paths'
 
 module ActionView
   module Helpers
     module AssetTagHelper
 
-      class AssetPaths
+      class AssetPaths < ActionView::Helpers::AssetPaths #:nodoc:
         # You can enable or disable the asset tag ids cache.
         # With the cache enabled, the asset tag helper methods will make fewer
         # expensive file system calls (the default implementation checks the file
@@ -14,31 +15,6 @@ module ActionView
         #   ActionView::Helpers::AssetTagHelper::AssetPaths.cache_asset_ids = false
         mattr_accessor :cache_asset_ids
 
-        attr_reader :config, :controller
-
-        def initialize(config, controller)
-          @config = config
-          @controller = controller
-        end
-
-        # Add the extension +ext+ if not present. Return full URLs otherwise untouched.
-        # Prefix with <tt>/dir/</tt> if lacking a leading +/+. Account for relative URL
-        # roots. Rewrite the asset path for cache-busting asset ids. Include
-        # asset host, if configured, with the correct request protocol.
-        def compute_public_path(source, dir, ext = nil, include_host = true)
-          return source if is_uri?(source)
-
-          source = rewrite_extension(source, dir, ext) if ext
-          source = "/#{dir}/#{source}" unless source[0] == ?/
-          source = rewrite_asset_path(source, config.asset_path)
-
-          has_request = controller.respond_to?(:request)
-          source = rewrite_relative_url_root(source, controller.config.relative_url_root) if has_request && include_host
-          source = rewrite_host_and_protocol(source, has_request) if include_host
-
-          source
-        end
-
         # Add or change an asset id in the asset id cache. This can be used
         # for SASS on Heroku.
         # :api: public
@@ -48,101 +24,76 @@ module ActionView
           end
         end
 
-        def is_uri?(path)
-          path =~ %r{^[-a-z]+://|^cid:}
-        end
+      private
 
-        private
+        def rewrite_extension(source, dir, ext)
+          source_ext = File.extname(source)
 
-          def rewrite_extension(source, dir, ext)
-            source_ext = File.extname(source)
+          source_with_ext = if source_ext.empty?
+            "#{source}.#{ext}"
+          elsif ext != source_ext[1..-1]
+            with_ext = "#{source}.#{ext}"
+            with_ext if File.exist?(File.join(config.assets_dir, dir, with_ext))
+          end
 
-            source_with_ext = if source_ext.empty?
-              "#{source}.#{ext}"
-            elsif ext != source_ext[1..-1]
-              with_ext = "#{source}.#{ext}"
-              with_ext if File.exist?(File.join(config.assets_dir, dir, with_ext))
-            end
+          source_with_ext || source
+        end
 
-            source_with_ext || source
-          end
+        # Break out the asset path rewrite in case plugins wish to put the asset id
+        # someplace other than the query string.
+        def rewrite_asset_path(source, dir)
+          source = "/#{dir}/#{source}" unless source[0] == ?/
+          path = config.asset_path
 
-          # Break out the asset path rewrite in case plugins wish to put the asset id
-          # someplace other than the query string.
-          def rewrite_asset_path(source, path = nil)
-            if path && path.respond_to?(:call)
-              return path.call(source)
-            elsif path && path.is_a?(String)
-              return path % [source]
-            end
+          if path && path.respond_to?(:call)
+            return path.call(source)
+          elsif path && path.is_a?(String)
+            return path % [source]
+          end
 
-            asset_id = rails_asset_id(source)
-            if asset_id.empty?
-              source
-            else
-              "#{source}?#{asset_id}"
-            end
+          asset_id = rails_asset_id(source)
+          if asset_id.empty?
+            source
+          else
+            "#{source}?#{asset_id}"
           end
+        end
 
-          mattr_accessor :asset_ids_cache
-          self.asset_ids_cache = {}
+        mattr_accessor :asset_ids_cache
+        self.asset_ids_cache = {}
 
-          mattr_accessor :asset_ids_cache_guard
-          self.asset_ids_cache_guard = Mutex.new
+        mattr_accessor :asset_ids_cache_guard
+        self.asset_ids_cache_guard = Mutex.new
 
-          # Use the RAILS_ASSET_ID environment variable or the source's
-          # modification time as its cache-busting asset id.
-          def rails_asset_id(source)
-            if asset_id = ENV["RAILS_ASSET_ID"]
+        # Use the RAILS_ASSET_ID environment variable or the source's
+        # modification time as its cache-busting asset id.
+        def rails_asset_id(source)
+          if asset_id = ENV["RAILS_ASSET_ID"]
+            asset_id
+          else
+            if self.cache_asset_ids && (asset_id = self.asset_ids_cache[source])
               asset_id
             else
-              if self.cache_asset_ids && (asset_id = self.asset_ids_cache[source])
-                asset_id
-              else
-                path = File.join(config.assets_dir, source)
-                asset_id = File.exist?(path) ? File.mtime(path).to_i.to_s : ''
-
-                if self.cache_asset_ids
-                  add_to_asset_ids_cache(source, asset_id)
-                end
+              path = File.join(config.assets_dir, source)
+              asset_id = File.exist?(path) ? File.mtime(path).to_i.to_s : ''
 
-                asset_id
+              if self.cache_asset_ids
+                add_to_asset_ids_cache(source, asset_id)
               end
-            end
-          end
-
-          def rewrite_relative_url_root(source, relative_url_root)
-            relative_url_root && !source.starts_with?("#{relative_url_root}/") ? "#{relative_url_root}#{source}" : source
-          end
 
-          def rewrite_host_and_protocol(source, has_request)
-            host = compute_asset_host(source)
-            if has_request && host && !is_uri?(host)
-              host = "#{controller.request.protocol}#{host}"
+              asset_id
             end
-            "#{host}#{source}"
           end
+        end
 
-          # Pick an asset host for this source. Returns +nil+ if no host is set,
-          # the host if no wildcard is set, the host interpolated with the
-          # numbers 0-3 if it contains <tt>%d</tt> (the number is the source hash mod 4),
-          # or the value returned from invoking the proc if it's a proc or the value from
-          # invoking call if it's an object responding to call.
-          def compute_asset_host(source)
-            if host = config.asset_host
-              if host.is_a?(Proc) || host.respond_to?(:call)
-                case host.is_a?(Proc) ? host.arity : host.method(:call).arity
-                when 2
-                  request = controller.respond_to?(:request) && controller.request
-                  host.call(source, request)
-                else
-                  host.call(source)
-                end
-              else
-                (host =~ /%d/) ? host % (source.hash % 4) : host
-              end
-            end
-          end
+        def rewrite_relative_url_root(source, relative_url_root)
+          relative_url_root && !source.starts_with?("#{relative_url_root}/") ? "#{relative_url_root}#{source}" : source
+        end
+
+        def rewrite_host_and_protocol(source, has_request)
+          source = rewrite_relative_url_root(source, controller.config.relative_url_root) if has_request
+          super(source, has_request)
+        end
       end
 
     end
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
index ce5a7dc2e5..e1ee0d0e1a 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/javascript_tag_helpers.rb
@@ -1,6 +1,5 @@
 require 'active_support/concern'
 require 'active_support/core_ext/file'
-require 'action_view/helpers/tag_helper'
 require 'action_view/helpers/asset_tag_helpers/asset_include_tag'
 
 module ActionView
@@ -8,8 +7,6 @@ module ActionView
     module AssetTagHelper
 
       class JavascriptIncludeTag < AssetIncludeTag
-        include TagHelper
-
         def asset_name
           'javascript'
         end
@@ -80,14 +77,14 @@ module ActionView
         # Used internally by javascript_include_tag to build the script path.
         #
         # ==== Examples
-        #   javascript_path "xmlhr" # => /javascripts/xmlhr.js
-        #   javascript_path "dir/xmlhr.js" # => /javascripts/dir/xmlhr.js
-        #   javascript_path "/dir/xmlhr" # => /dir/xmlhr.js
-        #   javascript_path "http://www.railsapplication.com/js/xmlhr" # => http://www.railsapplication.com/js/xmlhr
-        #   javascript_path "http://www.railsapplication.com/js/xmlhr.js" # => http://www.railsapplication.com/js/xmlhr.js
+        #   javascript_path "xmlhr"                              # => /javascripts/xmlhr.js
+        #   javascript_path "dir/xmlhr.js"                       # => /javascripts/dir/xmlhr.js
+        #   javascript_path "/dir/xmlhr"                         # => /dir/xmlhr.js
+        #   javascript_path "http://www.example.com/js/xmlhr"    # => http://www.example.com/js/xmlhr
+        #   javascript_path "http://www.example.com/js/xmlhr.js" # => http://www.example.com/js/xmlhr.js
         def javascript_path(source)
           if config.use_sprockets
-            sprockets_javascript_path(source)
+            asset_path(source, 'js')
           else
             asset_paths.compute_public_path(source, 'javascripts', 'js')
           end
@@ -102,10 +99,9 @@ module ActionView
         #
         # When passing paths, the ".js" extension is optional.
         #
-        # To include the default JavaScript expansion pass <tt>:defaults</tt> as source.
-        # By default, <tt>:defaults</tt> loads jQuery. If the application was generated
-        # with "-j prototype" the libraries Prototype and Scriptaculous are loaded instead.
-        # In any case, the defaults can be overridden in <tt>config/application.rb</tt>:
+        # If the application is not using the asset pipeline, to include the default JavaScript
+        # expansion pass <tt>:defaults</tt> as source. By default, <tt>:defaults</tt> loads jQuery,
+        # and that can be overridden in <tt>config/application.rb</tt>:
         #
         #   config.action_view.javascript_expansions[:defaults] = %w(foo.js bar.js)
         #
@@ -126,11 +122,11 @@ module ActionView
         #   # => <script type="text/javascript" src="/javascripts/common.javascript?1284139606"></script>
         #   #    <script type="text/javascript" src="/elsewhere/cools.js?1423139606"></script>
         #
-        #   javascript_include_tag "http://www.railsapplication.com/xmlhr"
-        #   # => <script type="text/javascript" src="http://www.railsapplication.com/xmlhr.js?1284139606"></script>
+        #   javascript_include_tag "http://www.example.com/xmlhr"
+        #   # => <script type="text/javascript" src="http://www.example.com/xmlhr.js?1284139606"></script>
         #
-        #   javascript_include_tag "http://www.railsapplication.com/xmlhr.js"
-        #   # => <script type="text/javascript" src="http://www.railsapplication.com/xmlhr.js?1284139606"></script>
+        #   javascript_include_tag "http://www.example.com/xmlhr.js"
+        #   # => <script type="text/javascript" src="http://www.example.com/xmlhr.js?1284139606"></script>
         #
         #   javascript_include_tag :defaults
         #   # => <script type="text/javascript" src="/javascripts/jquery.js?1284139606"></script>
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb
index a994afb65e..a95eb221be 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/stylesheet_tag_helpers.rb
@@ -1,6 +1,5 @@
 require 'active_support/concern'
 require 'active_support/core_ext/file'
-require 'action_view/helpers/tag_helper'
 require 'action_view/helpers/asset_tag_helpers/asset_include_tag'
 
 module ActionView
@@ -8,8 +7,6 @@ module ActionView
     module AssetTagHelper
 
       class StylesheetIncludeTag < AssetIncludeTag
-        include TagHelper
-
         def asset_name
           'stylesheet'
         end
@@ -57,14 +54,14 @@ module ActionView
         # Used internally by +stylesheet_link_tag+ to build the stylesheet path.
         #
         # ==== Examples
-        #   stylesheet_path "style" # => /stylesheets/style.css
-        #   stylesheet_path "dir/style.css" # => /stylesheets/dir/style.css
-        #   stylesheet_path "/dir/style.css" # => /dir/style.css
-        #   stylesheet_path "http://www.railsapplication.com/css/style" # => http://www.railsapplication.com/css/style
-        #   stylesheet_path "http://www.railsapplication.com/css/style.css" # => http://www.railsapplication.com/css/style.css
+        #   stylesheet_path "style"                                  # => /stylesheets/style.css
+        #   stylesheet_path "dir/style.css"                          # => /stylesheets/dir/style.css
+        #   stylesheet_path "/dir/style.css"                         # => /dir/style.css
+        #   stylesheet_path "http://www.example.com/css/style"       # => http://www.example.com/css/style
+        #   stylesheet_path "http://www.example.com/css/style.css"   # => http://www.example.com/css/style.css
         def stylesheet_path(source)
           if config.use_sprockets
-            sprockets_stylesheet_path(source)
+            asset_path(source, 'css')
           else
             asset_paths.compute_public_path(source, 'stylesheets', 'css')
           end
@@ -82,8 +79,8 @@ module ActionView
         #   stylesheet_link_tag "style.css" # =>
         #     <link href="/stylesheets/style.css" media="screen" rel="stylesheet" type="text/css" />
         #
-        #   stylesheet_link_tag "http://www.railsapplication.com/style.css" # =>
-        #     <link href="http://www.railsapplication.com/style.css" media="screen" rel="stylesheet" type="text/css" />
+        #   stylesheet_link_tag "http://www.example.com/style.css" # =>
+        #     <link href="http://www.example.com/style.css" media="screen" rel="stylesheet" type="text/css" />
         #
         #   stylesheet_link_tag "style", :media => "all" # =>
         #     <link href="/stylesheets/style.css" media="all" rel="stylesheet" type="text/css" />
diff --git a/actionpack/lib/action_view/helpers/capture_helper.rb b/actionpack/lib/action_view/helpers/capture_helper.rb
index 0139714240..ead7feb091 100644
--- a/actionpack/lib/action_view/helpers/capture_helper.rb
+++ b/actionpack/lib/action_view/helpers/capture_helper.rb
@@ -135,7 +135,7 @@ module ActionView
       # for elements that will be fragment cached.
       def content_for(name, content = nil, &block)
         content = capture(&block) if block_given?
-        result = @_view_flow.append(name, content) if content
+        result = @view_flow.append(name, content) if content
         result unless content
       end
 
@@ -146,7 +146,7 @@ module ActionView
       # the layout to stop looking for more contents.
       def provide(name, content = nil, &block)
         content = capture(&block) if block_given?
-        result = @_view_flow.append!(name, content) if content
+        result = @view_flow.append!(name, content) if content
         result unless content
       end
 
@@ -169,7 +169,7 @@ module ActionView
       #   </body>
       #   </html>
       def content_for?(name)
-        @_view_flow.get(name).present?
+        @view_flow.get(name).present?
       end
 
       # Use an alternate output buffer for the duration of the block.
diff --git a/actionpack/lib/action_view/helpers/controller_helper.rb b/actionpack/lib/action_view/helpers/controller_helper.rb
new file mode 100644
index 0000000000..e22331cb3c
--- /dev/null
+++ b/actionpack/lib/action_view/helpers/controller_helper.rb
@@ -0,0 +1,21 @@
+module ActionView
+  module Helpers
+    # This module keeps all methods and behavior in ActionView
+    # that simply delegates to the controller.
+    module ControllerHelper #:nodoc:
+      attr_internal :controller, :request
+
+      delegate :request_forgery_protection_token, :params, :session, :cookies, :response, :headers,
+               :flash, :action_name, :controller_name, :controller_path, :to => :controller
+
+      delegate :logger, :to => :controller, :allow_nil => true
+
+      def assign_controller(controller)
+        if @_controller = controller
+          @_request = controller.request if controller.respond_to?(:request)
+          @_config  = controller.config.inheritable_copy if controller.respond_to?(:config)
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/helpers/date_helper.rb b/actionpack/lib/action_view/helpers/date_helper.rb
index 313a2591bf..d2ddaafcb3 100644
--- a/actionpack/lib/action_view/helpers/date_helper.rb
+++ b/actionpack/lib/action_view/helpers/date_helper.rb
@@ -51,7 +51,7 @@ module ActionView
       #   distance_of_time_in_words(from_time, from_time + 15.seconds)        # => less than a minute
       #   distance_of_time_in_words(from_time, from_time + 15.seconds, true)  # => less than 20 seconds
       #   distance_of_time_in_words(from_time, 3.years.from_now)              # => about 3 years
-      #   distance_of_time_in_words(from_time, from_time + 60.hours)          # => about 3 days
+      #   distance_of_time_in_words(from_time, from_time + 60.hours)          # => 3 days
       #   distance_of_time_in_words(from_time, from_time + 45.seconds, true)  # => less than a minute
       #   distance_of_time_in_words(from_time, from_time - 45.seconds, true)  # => less than a minute
       #   distance_of_time_in_words(from_time, 76.seconds.from_now)           # => 1 minute
@@ -94,9 +94,20 @@ module ActionView
             when 43200..86399    then locale.t :about_x_months, :count => 1
             when 86400..525599   then locale.t :x_months,       :count => (distance_in_minutes.to_f / 43200.0).round
             else
-              distance_in_years           = distance_in_minutes / 525600
-              minute_offset_for_leap_year = (distance_in_years / 4) * 1440
-              remainder                   = ((distance_in_minutes - minute_offset_for_leap_year) % 525600)
+              fyear = from_time.year
+              fyear += 1 if from_time.month >= 3
+              tyear = to_time.year
+              tyear -= 1 if to_time.month < 3
+              leap_years = (fyear > tyear) ? 0 : (fyear..tyear).count{|x| Date.leap?(x)}
+              minute_offset_for_leap_year = leap_years * 1440
+              # Discount the leap year days when calculating year distance.
+              # e.g. if there are 20 leap year days between 2 dates having the same day
+              # and month then the based on 365 days calculation
+              # the distance in years will come out to over 80 years when in written
+              # english it would read better as about 80 years.
+              minutes_with_offset         = distance_in_minutes - minute_offset_for_leap_year
+              remainder                   = (minutes_with_offset % 525600)
+              distance_in_years           = (minutes_with_offset / 525600)
               if remainder < 131400
                 locale.t(:about_x_years,  :count => distance_in_years)
               elsif remainder < 394200
@@ -112,10 +123,12 @@ module ActionView
       #
       # ==== Examples
       #   time_ago_in_words(3.minutes.from_now)       # => 3 minutes
-      #   time_ago_in_words(Time.now - 15.hours)      # => 15 hours
+      #   time_ago_in_words(Time.now - 15.hours)      # => about 15 hours
       #   time_ago_in_words(Time.now)                 # => less than a minute
       #
-      #   from_time = Time.now - 3.days - 14.minutes - 25.seconds     # => 3 days
+      #   from_time = Time.now - 3.days - 14.minutes - 25.seconds
+      #   time_ago_in_words(from_time)      # => 3 days
+      #
       def time_ago_in_words(from_time, include_seconds = false)
         distance_of_time_in_words(from_time, Time.now, include_seconds)
       end
@@ -205,7 +218,8 @@ module ActionView
 
       # Returns a set of select tags (one for hour, minute and optionally second) pre-selected for accessing a
       # specified time-based attribute (identified by +method+) on an object assigned to the template (identified by
-      # +object+). You can include the seconds with <tt>:include_seconds</tt>.
+      # +object+). You can include the seconds with <tt>:include_seconds</tt>. You can get hours in the AM/PM format
+      # with <tt>:ampm</tt> option.
       #
       # This method will also generate 3 input hidden tags, for the actual year, month and day unless the option
       # <tt>:ignore_date</tt> is set to +true+.
@@ -228,6 +242,9 @@ module ActionView
       #   time_select("post", "written_on", :prompt => {:hour => true}) # generic prompt for hours
       #   time_select("post", "written_on", :prompt => true) # generic prompts for all
       #
+      #   # You can set :ampm option to true which will show the hours as: 12 PM, 01 AM .. 11 PM.
+      #   time_select 'game', 'game_time', {:ampm => true}
+      #
       # The selects are prepared for multi-parameter assignment to an Active Record object.
       #
       # Note: If the day is not included as an option but the month is, the day will be set to the 1st to ensure that
@@ -255,6 +272,9 @@ module ActionView
       #   # be stored in the trip variable in the departing attribute.
       #   datetime_select("trip", "departing", :default => 3.days.from_now)
       #
+      #   # Generate a datetime select with hours in the AM/PM format
+      #   datetime_select("post", "written_on", :ampm => true)
+      #
       #   # Generates a datetime select that discards the type that, when POSTed, will be stored in the post variable
       #   # as the written_on attribute.
       #   datetime_select("post", "written_on", :discard_type => true)
@@ -304,6 +324,9 @@ module ActionView
       #   # my_date_time (four days after today)
       #   select_datetime(my_date_time, :discard_type => true)
       #
+      #   # Generate a datetime field with hours in the AM/PM format
+      #   select_datetime(my_date_time, :ampm => true)
+      #
       #   # Generates a datetime select that defaults to the datetime in my_date_time (four days after today)
       #   # prefixed with 'payday' rather than 'date'
       #   select_datetime(my_date_time, :prefix => 'payday')
@@ -385,6 +408,9 @@ module ActionView
       #   # separated by ':' and includes an input for seconds
       #   select_time(my_time, :time_separator => ':', :include_seconds => true)
       #
+      #   # Generate a time select field with hours in the AM/PM format
+      #   select_time(my_time, :ampm => true)
+      #
       #   # Generates a time select with a custom prompt. Use :prompt=>true for generic prompts.
       #   select_time(my_time, :prompt => {:day => 'Choose day', :month => 'Choose month', :year => 'Choose year'})
       #   select_time(my_time, :prompt => {:hour => true}) # generic prompt for hours
@@ -464,7 +490,10 @@ module ActionView
       #
       #   # Generates a select field for hours with a custom prompt.  Use :prompt => true for a
       #   # generic prompt.
-      #   select_hour(13, :prompt =>'Choose hour')
+      #   select_hour(13, :prompt => 'Choose hour')
+      #
+      #   # Generate a select field for hours in the AM/PM format
+      #   select_hour(my_time, :ampm => true)
       #
       def select_hour(datetime, options = {}, html_options = {})
         DateTimeSelector.new(datetime, options, html_options).select_hour
@@ -599,6 +628,15 @@ module ActionView
         :year => 1, :month => 2, :day => 3, :hour => 4, :minute => 5, :second => 6
       }.freeze
 
+      AMPM_TRANSLATION = Hash[
+        [[0, "12 AM"], [1, "01 AM"], [2, "02 AM"], [3, "03 AM"],
+         [4, "04 AM"], [5, "05 AM"], [6, "06 AM"], [7, "07 AM"],
+         [8, "08 AM"], [9, "09 AM"], [10, "10 AM"], [11, "11 AM"],
+         [12, "12 PM"], [13, "01 PM"], [14, "02 PM"], [15, "03 PM"],
+         [16, "04 PM"], [17, "05 PM"], [18, "06 PM"], [19, "07 PM"],
+         [20, "08 PM"], [21, "09 PM"], [22, "10 PM"], [23, "11 PM"]]
+      ].freeze
+
       def initialize(datetime, options = {}, html_options = {})
         @options      = options.dup
         @html_options = html_options.dup
@@ -690,7 +728,7 @@ module ActionView
         if @options[:use_hidden] || @options[:discard_hour]
           build_hidden(:hour, hour)
         else
-          build_options_and_select(:hour, hour, :end => 23)
+          build_options_and_select(:hour, hour, :end => 23, :ampm => @options[:ampm])
         end
       end
 
@@ -808,7 +846,7 @@ module ActionView
           start         = options.delete(:start) || 0
           stop          = options.delete(:end) || 59
           step          = options.delete(:step) || 1
-          options.reverse_merge!({:leading_zeros => true})
+          options.reverse_merge!({:leading_zeros => true, :ampm => false})
           leading_zeros = options.delete(:leading_zeros)
 
           select_options = []
@@ -816,7 +854,8 @@ module ActionView
             value = leading_zeros ? sprintf("%02d", i) : i
             tag_options = { :value => value }
             tag_options[:selected] = "selected" if selected == i
-            select_options << content_tag(:option, value, tag_options)
+            text = options[:ampm] ? AMPM_TRANSLATION[i] : value
+            select_options << content_tag(:option, text, tag_options)
           end
           (select_options.join("\n") + "\n").html_safe
         end
diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index 440acafa88..b6bb90a3ce 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -102,6 +102,11 @@ module ActionView
       include FormTagHelper
       include UrlHelper
 
+      # Converts the given object to an ActiveModel compliant one.
+      def convert_to_model(object)
+        object.respond_to?(:to_model) ? object.to_model : object
+      end
+
       # Creates a form and a scope around a specific model object that is used
       # as a base for questioning about values for the fields.
       #
@@ -947,7 +952,8 @@ module ActionView
           label_tag(name_and_id["id"], options, &block)
         else
           content = if text.blank?
-            I18n.t("helpers.label.#{object_name}.#{method_name}", :default => "").presence
+            method_and_value = tag_value.present? ? "#{method_name}.#{tag_value}" : method_name
+            I18n.t("helpers.label.#{object_name}.#{method_and_value}", :default => "").presence
           else
             text.to_s
           end
@@ -1166,7 +1172,7 @@ module ActionView
     class FormBuilder
       # The methods which wrap a form helper call.
       class_attribute :field_helpers
-      self.field_helpers = (FormHelper.instance_method_names - ['form_for'])
+      self.field_helpers = FormHelper.instance_method_names - %w(form_for convert_to_model)
 
       attr_accessor :object_name, :object, :options
 
diff --git a/actionpack/lib/action_view/helpers/form_tag_helper.rb b/actionpack/lib/action_view/helpers/form_tag_helper.rb
index 49aa434020..9e0f8f32b7 100644
--- a/actionpack/lib/action_view/helpers/form_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_tag_helper.rb
@@ -74,6 +74,8 @@ module ActionView
       # ==== Options
       # * <tt>:multiple</tt> - If set to true the selection will allow multiple choices.
       # * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
+      # * <tt>:include_blank</tt> - If set to true, an empty option will be create
+      # * <tt>:prompt</tt> - Create a prompt option with blank value and the text asking user to select something
       # * Any other key creates standard HTML attributes for the tag.
       #
       # ==== Examples
@@ -99,18 +101,26 @@ module ActionView
       #   # => <select class="form_input" id="access" multiple="multiple" name="access[]"><option>Read</option>
       #   #    <option>Write</option></select>
       #
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name"), :include_blank => true
+      #   # => <select id="people" name="people"><option value=""></option><option value="1">David</option></select>
+      #
+      #   select_tag "people", options_from_collection_for_select(@people, "id", "name"), :prompt => "Select something"
+      #   # => <select id="people" name="people"><option value="">Select something</option><option value="1">David</option></select>
+      #
       #   select_tag "destination", "<option>NYC</option><option>Paris</option><option>Rome</option>", :disabled => true
       #   # => <select disabled="disabled" id="destination" name="destination"><option>NYC</option>
       #   #    <option>Paris</option><option>Rome</option></select>
       def select_tag(name, option_tags = nil, options = {})
         html_name = (options[:multiple] == true && !name.to_s.ends_with?("[]")) ? "#{name}[]" : name
-        if blank = options.delete(:include_blank)
-          if blank.kind_of?(String)
-            option_tags = "<option value=\"\">#{blank}</option>".html_safe + option_tags
-          else
-            option_tags = "<option value=\"\"></option>".html_safe + option_tags
-          end
+
+        if options.delete(:include_blank)
+          option_tags = "<option value=\"\"></option>".html_safe + option_tags
+        end
+
+        if prompt = options.delete(:prompt)
+          option_tags = "<option value=\"\">#{prompt}</option>".html_safe + option_tags
         end
+
         content_tag :select, option_tags, { "name" => html_name, "id" => sanitize_to_id(name) }.update(options.stringify_keys)
       end
 
diff --git a/actionpack/lib/action_view/helpers/number_helper.rb b/actionpack/lib/action_view/helpers/number_helper.rb
index 05a9c5b4f1..63d13a0f0b 100644
--- a/actionpack/lib/action_view/helpers/number_helper.rb
+++ b/actionpack/lib/action_view/helpers/number_helper.rb
@@ -100,7 +100,7 @@ module ActionView
       #  number_to_currency(1234567890.506, :precision => 3)  # => $1,234,567,890.506
       #  number_to_currency(1234567890.506, :locale => :fr)   # => 1 234 567 890,506 €
       #
-      #  number_to_currency(1234567890.50, :negative_format => "(%u%n)")
+      #  number_to_currency(-1234567890.50, :negative_format => "(%u%n)")
       #  # => ($1,234,567,890.51)
       #  number_to_currency(1234567890.50, :unit => "&pound;", :separator => ",", :delimiter => "")
       #  # => &pound;1234567890,50
@@ -238,7 +238,7 @@ module ActionView
       #  number_with_precision(111.2345, :precision => 1, :significant => true)     # => 100
       #  number_with_precision(13, :precision => 5, :significant => true)           # => 13.000
       #  number_with_precision(111.234, :locale => :fr)                             # => 111,234
-      #  number_with_precision(13, :precision => 5, :significant => true, strip_insignificant_zeros => true)
+      #  number_with_precision(13, :precision => 5, :significant => true, :strip_insignificant_zeros => true)
       #  # => 13
       #  number_with_precision(389.32314, :precision => 4, :significant => true)    # => 389.3
       #  number_with_precision(1111.2345, :precision => 2, :separator => ',', :delimiter => '.')
@@ -304,6 +304,7 @@ module ActionView
       # * <tt>:separator</tt>  - Sets the separator between the fractional and integer digits (defaults to ".").
       # * <tt>:delimiter</tt>  - Sets the thousands delimiter (defaults to "").
       # * <tt>:strip_insignificant_zeros</tt>  - If +true+ removes insignificant zeros after the decimal separator (defaults to +true+)
+      # * <tt>:prefix</tt>  - If +:si+ formats the number using the SI prefix (defaults to :binary)
       # ==== Examples
       #  number_to_human_size(123)                                          # => 123 Bytes
       #  number_to_human_size(1234)                                         # => 1.21 KB
@@ -318,7 +319,7 @@ module ActionView
       # Non-significant zeros after the fractional separator are stripped out by default (set
       # <tt>:strip_insignificant_zeros</tt> to +false+ to change that):
       #  number_to_human_size(1234567890123, :precision => 5)        # => "1.1229 TB"
-      #  number_to_human_size(524288000, :precision=>5)              # => "500 MB"
+      #  number_to_human_size(524288000, :precision => 5)            # => "500 MB"
       def number_to_human_size(number, options = {})
         options.symbolize_keys!
 
@@ -341,15 +342,17 @@ module ActionView
         options[:strip_insignificant_zeros] = true if not options.key?(:strip_insignificant_zeros)
 
         storage_units_format = I18n.translate(:'number.human.storage_units.format', :locale => options[:locale], :raise => true)
+        
+        base = options[:prefix] == :si ? 1000 : 1024
 
-        if number.to_i < 1024
+        if number.to_i < base
           unit = I18n.translate(:'number.human.storage_units.units.byte', :locale => options[:locale], :count => number.to_i, :raise => true)
           storage_units_format.gsub(/%n/, number.to_i.to_s).gsub(/%u/, unit).html_safe
         else
           max_exp  = STORAGE_UNITS.size - 1
-          exponent = (Math.log(number) / Math.log(1024)).to_i # Convert to base 1024
+          exponent = (Math.log(number) / Math.log(base)).to_i # Convert to base
           exponent = max_exp if exponent > max_exp # we need this to avoid overflow for the highest unit
-          number  /= 1024 ** exponent
+          number  /= base ** exponent
 
           unit_key = STORAGE_UNITS[exponent]
           unit = I18n.translate(:"number.human.storage_units.units.#{unit_key}", :locale => options[:locale], :count => number, :raise => true)
@@ -407,7 +410,7 @@ module ActionView
       # Unsignificant zeros after the decimal separator are stripped out by default (set
       # <tt>:strip_insignificant_zeros</tt> to +false+ to change that):
       #  number_to_human(12345012345, :significant_digits => 6)       # => "12.345 Billion"
-      #  number_to_human(500000000, :precision=>5)                    # => "500 Million"
+      #  number_to_human(500000000, :precision => 5)                  # => "500 Million"
       #
       # ==== Custom Unit Quantifiers
       #
diff --git a/actionpack/lib/action_view/helpers/record_tag_helper.rb b/actionpack/lib/action_view/helpers/record_tag_helper.rb
index 4d300a1469..142a25f118 100644
--- a/actionpack/lib/action_view/helpers/record_tag_helper.rb
+++ b/actionpack/lib/action_view/helpers/record_tag_helper.rb
@@ -10,7 +10,7 @@ module ActionView
       # relate to the specified Active Record object. Usage example:
       #
       #    <%= div_for(@person, :class => "foo") do %>
-      #       <%=h @person.name %>
+      #       <%= @person.name %>
       #    <% end %>
       #
       # produces:
@@ -25,8 +25,8 @@ module ActionView
       # that relate to the specified Active Record object. For example:
       #
       #    <%= content_tag_for(:tr, @person) do %>
-      #      <td><%=h @person.first_name %></td>
-      #      <td><%=h @person.last_name %></td>
+      #      <td><%= @person.first_name %></td>
+      #      <td><%= @person.last_name %></td>
       #    <% end %>
       #
       # would produce the following HTML (assuming @person is an instance of
diff --git a/actionpack/lib/action_view/helpers/rendering_helper.rb b/actionpack/lib/action_view/helpers/rendering_helper.rb
new file mode 100644
index 0000000000..47efdded42
--- /dev/null
+++ b/actionpack/lib/action_view/helpers/rendering_helper.rb
@@ -0,0 +1,90 @@
+module ActionView
+  module Helpers
+    # = Action View Rendering
+    #
+    # Implements methods that allow rendering from a view context.
+    # In order to use this module, all you need is to implement
+    # view_renderer that returns an ActionView::Renderer object.
+    module RenderingHelper
+      # Returns the result of a render that's dictated by the options hash. The primary options are:
+      #
+      # * <tt>:partial</tt> - See ActionView::Partials.
+      # * <tt>:file</tt> - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
+      # * <tt>:inline</tt> - Renders an inline template similar to how it's done in the controller.
+      # * <tt>:text</tt> - Renders the text passed in out.
+      #
+      # If no options hash is passed or :update specified, the default is to render a partial and use the second parameter
+      # as the locals hash.
+      def render(options = {}, locals = {}, &block)
+        case options
+        when Hash
+          if block_given?
+            view_renderer.render_partial(self, options.merge(:partial => options[:layout]), &block)
+          else
+            view_renderer.render(self, options)
+          end
+        else
+          view_renderer.render_partial(self, :partial => options, :locals => locals)
+        end
+      end
+
+      # Overwrites _layout_for in the context object so it supports the case a block is
+      # passed to a partial. Returns the contents that are yielded to a layout, given a
+      # name or a block.
+      #
+      # You can think of a layout as a method that is called with a block. If the user calls
+      # <tt>yield :some_name</tt>, the block, by default, returns <tt>content_for(:some_name)</tt>.
+      # If the user calls simply +yield+, the default block returns <tt>content_for(:layout)</tt>.
+      #
+      # The user can override this default by passing a block to the layout:
+      #
+      #   # The template
+      #   <%= render :layout => "my_layout" do %>
+      #     Content
+      #   <% end %>
+      #
+      #   # The layout
+      #   <html>
+      #     <%= yield %>
+      #   </html>
+      #
+      # In this case, instead of the default block, which would return <tt>content_for(:layout)</tt>,
+      # this method returns the block that was passed in to <tt>render :layout</tt>, and the response
+      # would be
+      #
+      #   <html>
+      #     Content
+      #   </html>
+      #
+      # Finally, the block can take block arguments, which can be passed in by +yield+:
+      #
+      #   # The template
+      #   <%= render :layout => "my_layout" do |customer| %>
+      #     Hello <%= customer.name %>
+      #   <% end %>
+      #
+      #   # The layout
+      #   <html>
+      #     <%= yield Struct.new(:name).new("David") %>
+      #   </html>
+      #
+      # In this case, the layout would receive the block passed into <tt>render :layout</tt>,
+      # and the struct specified would be passed into the block as an argument. The result
+      # would be
+      #
+      #   <html>
+      #     Hello David
+      #   </html>
+      #
+      def _layout_for(*args, &block)
+        name = args.first
+
+        if block && !name.is_a?(Symbol)
+          capture(*args, &block)
+        else
+          super
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/helpers/sanitize_helper.rb b/actionpack/lib/action_view/helpers/sanitize_helper.rb
index 0fee34f8a4..841be0a567 100644
--- a/actionpack/lib/action_view/helpers/sanitize_helper.rb
+++ b/actionpack/lib/action_view/helpers/sanitize_helper.rb
@@ -94,7 +94,7 @@ module ActionView
       #   # => Please e-mail me at me@email.com.
       #
       #   strip_links('Blog: <a href="http://www.myblog.com/" class="nav" target=\"_blank\">Visit</a>.')
-      #   # => Blog: Visit
+      #   # => Blog: Visit.
       def strip_links(html)
         self.class.link_sanitizer.sanitize(html)
       end
diff --git a/actionpack/lib/action_view/helpers/sprockets_helper.rb b/actionpack/lib/action_view/helpers/sprockets_helper.rb
index 408a2030ab..ab98da9624 100644
--- a/actionpack/lib/action_view/helpers/sprockets_helper.rb
+++ b/actionpack/lib/action_view/helpers/sprockets_helper.rb
@@ -1,85 +1,69 @@
 require 'uri'
+require 'action_view/helpers/asset_paths'
 
 module ActionView
   module Helpers
     module SprocketsHelper
-      def sprockets_javascript_path(source)
-        compute_sprockets_path source, 'assets', 'js'
+      def asset_path(source, default_ext = nil)
+        sprockets_asset_paths.compute_public_path(source, 'assets', default_ext, true)
       end
 
       def sprockets_javascript_include_tag(source, options = {})
         options = {
           'type' => "text/javascript",
-          'src'  => sprockets_javascript_path(source)
+          'src'  => asset_path(source, 'js')
         }.merge(options.stringify_keys)
 
         content_tag 'script', "", options
       end
 
-      def sprockets_stylesheet_path(source)
-        compute_sprockets_path source, 'assets', 'css'
-      end
-
       def sprockets_stylesheet_link_tag(source, options = {})
         options = {
           'rel'   => "stylesheet",
           'type'  => "text/css",
           'media' => "screen",
-          'href'  => sprockets_stylesheet_path(source)
+          'href'  => asset_path(source, 'css')
         }.merge(options.stringify_keys)
 
         tag 'link', options
       end
 
       private
-        def compute_sprockets_path(source, dir, default_ext)
-          source = source.to_s
-
-          return source if URI.parse(source).host
-
-          # Add /javscripts to relative paths
-          if source[0] != ?/
-            source = "/#{dir}/#{source}"
-          end
-
-          # Add default extension if there isn't one
-          if default_ext && File.extname(source).empty?
-            source = "#{source}.#{default_ext}"
-          end
 
-          # Fingerprint url
-          if source =~ /^\/#{dir}\/(.+)/
-            source = assets.path($1, config.perform_caching, dir)
-          end
-
-          host = compute_asset_host(source)
+      def sprockets_asset_paths
+        @sprockets_asset_paths ||= begin
+          config     = self.config if respond_to?(:config)
+          controller = self.controller if respond_to?(:controller)
+          SprocketsHelper::AssetPaths.new(config, controller)
+        end
+      end
 
-          if controller.respond_to?(:request) && host && URI.parse(host).host
-            source = "#{controller.request.protocol}#{host}#{source}"
+      class AssetPaths < ActionView::Helpers::AssetPaths #:nodoc:
+        def rewrite_asset_path(source, dir)
+          if source[0] == ?/
+            source
+          else
+            assets.path(source, performing_caching?, dir)
           end
-
-          source
         end
 
-        def compute_asset_host(source)
-          if host = config.asset_host
-            if host.is_a?(Proc) || host.respond_to?(:call)
-              case host.is_a?(Proc) ? host.arity : host.method(:call).arity
-              when 2
-                request = controller.respond_to?(:request) && controller.request
-                host.call(source, request)
-              else
-                host.call(source)
-              end
-            else
-              (host =~ /%d/) ? host % (source.hash % 4) : host
-            end
+        def rewrite_extension(source, dir, ext)
+          if ext && File.extname(source).empty?
+            "#{source}.#{ext}"
+          else
+            source
           end
         end
 
         def assets
           Rails.application.assets
         end
+
+        # When included in Sprockets::Context, we need to ask the top-level config as the controller is not available
+        def performing_caching?
+          @config ?  @config.perform_caching : Rails.application.config.action_controller.perform_caching
+        end
+      end
     end
   end
-end
+end
\ No newline at end of file
diff --git a/actionpack/lib/action_view/helpers/text_helper.rb b/actionpack/lib/action_view/helpers/text_helper.rb
index bdda1df437..ca09c77b5c 100644
--- a/actionpack/lib/action_view/helpers/text_helper.rb
+++ b/actionpack/lib/action_view/helpers/text_helper.rb
@@ -19,7 +19,7 @@ module ActionView
     #   simple_format('<a href="http://example.com/">Example</a>')
     #   # => "<p><a href=\"http://example.com/\">Example</a></p>"
     #
-    #   simple_format('<a href="javascript:alert('no!')">Example</a>')
+    #   simple_format('<a href="javascript:alert(\'no!\')">Example</a>')
     #   # => "<p><a>Example</a></p>"
     #
     # If you want to escape all content, you should invoke the +h+ method before
@@ -265,60 +265,6 @@ module ActionView
         text.html_safe.safe_concat("</p>")
       end
 
-      # Turns all URLs and e-mail addresses into clickable links. The <tt>:link</tt> option
-      # will limit what should be linked. You can add HTML attributes to the links using
-      # <tt>:html</tt>. Possible values for <tt>:link</tt> are <tt>:all</tt> (default),
-      # <tt>:email_addresses</tt>, and <tt>:urls</tt>. If a block is given, each URL and
-      # e-mail address is yielded and the result is used as the link text.
-      #
-      # ==== Examples
-      #   auto_link("Go to http://www.rubyonrails.org and say hello to david@loudthinking.com")
-      #   # => "Go to <a href=\"http://www.rubyonrails.org\">http://www.rubyonrails.org</a> and
-      #   #     say hello to <a href=\"mailto:david@loudthinking.com\">david@loudthinking.com</a>"
-      #
-      #   auto_link("Visit http://www.loudthinking.com/ or e-mail david@loudthinking.com", :link => :urls)
-      #   # => "Visit <a href=\"http://www.loudthinking.com/\">http://www.loudthinking.com/</a>
-      #   #     or e-mail david@loudthinking.com"
-      #
-      #   auto_link("Visit http://www.loudthinking.com/ or e-mail david@loudthinking.com", :link => :email_addresses)
-      #   # => "Visit http://www.loudthinking.com/ or e-mail <a href=\"mailto:david@loudthinking.com\">david@loudthinking.com</a>"
-      #
-      #   post_body = "Welcome to my new blog at http://www.myblog.com/.  Please e-mail me at me@email.com."
-      #   auto_link(post_body, :html => { :target => '_blank' }) do |text|
-      #     truncate(text, :length => 15)
-      #   end
-      #   # => "Welcome to my new blog at <a href=\"http://www.myblog.com/\" target=\"_blank\">http://www.m...</a>.
-      #         Please e-mail me at <a href=\"mailto:me@email.com\">me@email.com</a>."
-      #
-      #
-      # You can still use <tt>auto_link</tt> with the old API that accepts the
-      # +link+ as its optional second parameter and the +html_options+ hash
-      # as its optional third parameter:
-      #   post_body = "Welcome to my new blog at http://www.myblog.com/. Please e-mail me at me@email.com."
-      #   auto_link(post_body, :urls)     # => Once upon\na time
-      #   # => "Welcome to my new blog at <a href=\"http://www.myblog.com/\">http://www.myblog.com</a>.
-      #         Please e-mail me at me@email.com."
-      #
-      #   auto_link(post_body, :all, :target => "_blank")     # => Once upon\na time
-      #   # => "Welcome to my new blog at <a href=\"http://www.myblog.com/\" target=\"_blank\">http://www.myblog.com</a>.
-      #         Please e-mail me at <a href=\"mailto:me@email.com\">me@email.com</a>."
-      def auto_link(text, *args, &block)#link = :all, html = {}, &block)
-        return '' if text.blank?
-
-        options = args.size == 2 ? {} : args.extract_options! # this is necessary because the old auto_link API has a Hash as its last parameter
-        unless args.empty?
-          options[:link] = args[0] || :all
-          options[:html] = args[1] || {}
-        end
-        options.reverse_merge!(:link => :all, :html => {})
-
-        case options[:link].to_sym
-          when :all                         then auto_link_email_addresses(auto_link_urls(text, options[:html], options, &block), options[:html], &block)
-          when :email_addresses             then auto_link_email_addresses(text, options[:html], &block)
-          when :urls                        then auto_link_urls(text, options[:html], options, &block)
-        end
-      end
-
       # Creates a Cycle object whose _to_s_ method cycles through elements of an
       # array every time it is called. This can be used for example, to alternate
       # classes for table rows.  You can use named cycles to allow nesting in loops.
@@ -464,77 +410,6 @@ module ActionView
           @_cycles = Hash.new unless defined?(@_cycles)
           @_cycles[name] = cycle_object
         end
-
-        AUTO_LINK_RE = %r{
-            (?: ([0-9A-Za-z+.:-]+:)// | www\. )
-            [^\s<]+
-          }x
-
-        # regexps for determining context, used high-volume
-        AUTO_LINK_CRE = [/<[^>]+$/, /^[^>]*>/, /<a\b.*?>/i, /<\/a>/i]
-
-        AUTO_EMAIL_RE = /[\w.!#\$%+-]+@[\w-]+(?:\.[\w-]+)+/
-
-        BRACKETS = { ']' => '[', ')' => '(', '}' => '{' }
-
-        # Turns all urls into clickable links.  If a block is given, each url
-        # is yielded and the result is used as the link text.
-        def auto_link_urls(text, html_options = {}, options = {})
-          link_attributes = html_options.stringify_keys
-          text.gsub(AUTO_LINK_RE) do
-            scheme, href = $1, $&
-            punctuation = []
-
-            if auto_linked?($`, $')
-              # do not change string; URL is already linked
-              href
-            else
-              # don't include trailing punctuation character as part of the URL
-              while href.sub!(/[^\w\/-]$/, '')
-                punctuation.push $&
-                if opening = BRACKETS[punctuation.last] and href.scan(opening).size > href.scan(punctuation.last).size
-                  href << punctuation.pop
-                  break
-                end
-              end
-
-              link_text = block_given?? yield(href) : href
-              href = 'http://' + href unless scheme
-
-              unless options[:sanitize] == false
-                link_text = sanitize(link_text)
-                href      = sanitize(href)
-              end
-              content_tag(:a, link_text, link_attributes.merge('href' => href), !!options[:sanitize]) + punctuation.reverse.join('')
-            end
-          end
-        end
-
-        # Turns all email addresses into clickable links.  If a block is given,
-        # each email is yielded and the result is used as the link text.
-        def auto_link_email_addresses(text, html_options = {}, options = {})
-          text.gsub(AUTO_EMAIL_RE) do
-            text = $&
-
-            if auto_linked?($`, $')
-              text.html_safe
-            else
-              display_text = (block_given?) ? yield(text) : text
-
-              unless options[:sanitize] == false
-                text         = sanitize(text)
-                display_text = sanitize(display_text) unless text == display_text
-              end
-              mail_to text, display_text, html_options
-            end
-          end
-        end
-
-        # Detects already linked context or position in the middle of a tag
-        def auto_linked?(left, right)
-          (left =~ AUTO_LINK_CRE[0] and right =~ AUTO_LINK_CRE[1]) or
-            (left.rindex(AUTO_LINK_CRE[2]) and $' !~ AUTO_LINK_CRE[3])
-        end
     end
   end
 end
diff --git a/actionpack/lib/action_view/helpers/translation_helper.rb b/actionpack/lib/action_view/helpers/translation_helper.rb
index 59e6ce878f..ec9bdd5320 100644
--- a/actionpack/lib/action_view/helpers/translation_helper.rb
+++ b/actionpack/lib/action_view/helpers/translation_helper.rb
@@ -5,7 +5,7 @@ module I18n
   class ExceptionHandler
     include Module.new {
       def call(exception, locale, key, options)
-        exception.is_a?(MissingTranslationData) ? super.html_safe : super
+        exception.is_a?(MissingTranslation) ? super.html_safe : super
       end
     }
   end
@@ -17,8 +17,8 @@ module ActionView
     module TranslationHelper
       # Delegates to I18n#translate but also performs three additional functions.
       #
-      # First, it'll pass the :rescue_format => :html option to I18n so that any caught
-      # MissingTranslationData exceptions will be turned into inline spans that
+      # First, it'll pass the :rescue_format => :html option to I18n so that any
+      # thrown MissingTranslation messages will be turned into inline spans that
       #
       #   * have a "translation-missing" class set,
       #   * contain the missing key as a title attribute and
@@ -63,8 +63,8 @@ module ActionView
       private
         def scope_key_by_partial(key)
           if key.to_s.first == "."
-            if (path = @_template && @_template.virtual_path)
-              path.gsub(%r{/_?}, ".") + key.to_s
+            if @virtual_path
+              @virtual_path.gsub(%r{/_?}, ".") + key.to_s
             else
               raise "Cannot use t(#{key.inspect}) shortcut because path is not available"
             end
diff --git a/actionpack/lib/action_view/helpers/url_helper.rb b/actionpack/lib/action_view/helpers/url_helper.rb
index de75488e72..ffa9a5bb0b 100644
--- a/actionpack/lib/action_view/helpers/url_helper.rb
+++ b/actionpack/lib/action_view/helpers/url_helper.rb
@@ -68,7 +68,7 @@ module ActionView
       #   # => /books/find
       #
       #   <%= url_for(:action => 'login', :controller => 'members', :only_path => false, :protocol => 'https') %>
-      #   # => https://www.railsapplication.com/members/login/
+      #   # => https://www.example.com/members/login/
       #
       #   <%= url_for(:action => 'play', :anchor => 'player') %>
       #   # => /messages/play/#player
@@ -555,10 +555,10 @@ module ActionView
       #   current_page?(:controller => 'shop', :action => 'checkout')
       #   # => true
       #
-      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page=>'1')
+      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page => '1')
       #   # => true
       #
-      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page=>'2')
+      #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc', :page => '2')
       #   # => false
       #
       #   current_page?(:controller => 'shop', :action => 'checkout', :order => 'desc')
diff --git a/actionpack/lib/action_view/lookup_context.rb b/actionpack/lib/action_view/lookup_context.rb
index 06c607931d..f0ed3425de 100644
--- a/actionpack/lib/action_view/lookup_context.rb
+++ b/actionpack/lib/action_view/lookup_context.rb
@@ -9,6 +9,8 @@ module ActionView
   # generate a key, given to view paths, used in the resolver cache lookup. Since
   # this key is generated just once during the request, it speeds up all cache accesses.
   class LookupContext #:nodoc:
+    attr_accessor :prefixes
+    
     mattr_accessor :fallbacks
     @@fallbacks = FallbackFileSystemResolver.instances
 
@@ -58,10 +60,11 @@ module ActionView
       end
     end
 
-    def initialize(view_paths, details = {})
+    def initialize(view_paths, details = {}, prefixes = [])
       @details, @details_key = { :handlers => default_handlers }, nil
       @frozen_formats, @skip_default_locale = false, false
       @cache = true
+      @prefixes = prefixes
 
       self.view_paths = view_paths
       self.registered_detail_setters.each do |key, setter|
@@ -164,12 +167,12 @@ module ActionView
         @frozen_formats = true
       end
 
-      # Overload formats= to reject ["*/*"] values.
+      # Overload formats= to expand ["*/*"] values and automatically
+      # add :html as fallback to :js.
       def formats=(values)
-        if values && values.size == 1
-          value = values.first
-          values = nil    if value == "*/*"
-          values << :html if value == :js
+        if values
+          values.concat(_formats_defaults) if values.delete "*/*"
+          values << :html if values == [:js]
         end
         super(values)
       end
diff --git a/actionpack/lib/action_view/partials.rb b/actionpack/lib/action_view/partials.rb
deleted file mode 100644
index c181689e62..0000000000
--- a/actionpack/lib/action_view/partials.rb
+++ /dev/null
@@ -1,226 +0,0 @@
-require 'active_support/core_ext/object/blank'
-
-module ActionView
-  # = Action View Partials
-  #
-  # There's also a convenience method for rendering sub templates within the current controller that depends on a
-  # single object (we call this kind of sub templates for partials). It relies on the fact that partials should
-  # follow the naming convention of being prefixed with an underscore -- as to separate them from regular
-  # templates that could be rendered on their own.
-  #
-  # In a template for Advertiser#account:
-  #
-  #  <%= render :partial => "account" %>
-  #
-  # This would render "advertiser/_account.html.erb" and pass the instance variable @account in as a local variable
-  # +account+ to the template for display.
-  #
-  # In another template for Advertiser#buy, we could have:
-  #
-  #   <%= render :partial => "account", :locals => { :account => @buyer } %>
-  #
-  #   <% @advertisements.each do |ad| %>
-  #     <%= render :partial => "ad", :locals => { :ad => ad } %>
-  #   <% end %>
-  #
-  # This would first render "advertiser/_account.html.erb" with @buyer passed in as the local variable +account+, then
-  # render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display.
-  #
-  # == The :as and :object options
-  #
-  # By default <tt>ActionView::Partials::PartialRenderer</tt> has its object in a local variable with the same
-  # name as the template. So, given
-  #
-  #   <%= render :partial => "contract" %>
-  #
-  # within contract we'll get <tt>@contract</tt> in the local variable +contract+, as if we had written
-  #
-  #   <%= render :partial => "contract", :locals => { :contract  => @contract } %>
-  #
-  # With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we
-  # wanted it to be +agreement+ instead of +contract+ we'd do:
-  #
-  #   <%= render :partial => "contract", :as => 'agreement' %>
-  #
-  # The <tt>:object</tt> option can be used to directly specify which object is rendered into the partial;
-  # useful when the template's object is elsewhere, in a different ivar or in a local variable for instance.
-  #
-  # Revisiting a previous example we could have written this code:
-  #
-  #   <%= render :partial => "account", :object => @buyer %>
-  #
-  #   <% @advertisements.each do |ad| %>
-  #     <%= render :partial => "ad", :object => ad %>
-  #   <% end %>
-  #
-  # The <tt>:object</tt> and <tt>:as</tt> options can be used together.
-  #
-  # == Rendering a collection of partials
-  #
-  # The example of partial use describes a familiar pattern where a template needs to iterate over an array and
-  # render a sub template for each of the elements. This pattern has been implemented as a single method that
-  # accepts an array and renders a partial by the same name as the elements contained within. So the three-lined
-  # example in "Using partials" can be rewritten with a single line:
-  #
-  #   <%= render :partial => "ad", :collection => @advertisements %>
-  #
-  # This will render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display. An
-  # iteration counter will automatically be made available to the template with a name of the form
-  # +partial_name_counter+. In the case of the example above, the template would be fed +ad_counter+.
-  #
-  # The <tt>:as</tt> option may be used when rendering partials.
-  #
-  # You can specify a partial to be rendered between elements via the <tt>:spacer_template</tt> option.
-  # The following example will render <tt>advertiser/_ad_divider.html.erb</tt> between each ad partial:
-  #
-  #   <%= render :partial => "ad", :collection => @advertisements, :spacer_template => "ad_divider" %>
-  #
-  # If the given <tt>:collection</tt> is nil or empty, <tt>render</tt> will return nil. This will allow you
-  # to specify a text which will displayed instead by using this form:
-  #
-  #   <%= render(:partial => "ad", :collection => @advertisements) || "There's no ad to be displayed" %>
-  #
-  # NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also
-  # just keep domain objects, like Active Records, in there.
-  #
-  # == Rendering shared partials
-  #
-  # Two controllers can share a set of partials and render them like this:
-  #
-  #   <%= render :partial => "advertisement/ad", :locals => { :ad => @advertisement } %>
-  #
-  # This will render the partial "advertisement/_ad.html.erb" regardless of which controller this is being called from.
-  #
-  # == Rendering objects with the RecordIdentifier
-  #
-  # Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if
-  # you're following its conventions for RecordIdentifier#partial_path. Examples:
-  #
-  #  # @account is an Account instance, so it uses the RecordIdentifier to replace
-  #  # <%= render :partial => "accounts/account", :locals => { :account => @account} %>
-  #  <%= render :partial => @account %>
-  #
-  #  # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
-  #  # <%= render :partial => "posts/post", :collection => @posts %>
-  #  <%= render :partial => @posts %>
-  #
-  # == Rendering the default case
-  #
-  # If you're not going to be using any of the options like collections or layouts, you can also use the short-hand
-  # defaults of render to render partials. Examples:
-  #
-  #  # Instead of <%= render :partial => "account" %>
-  #  <%= render "account" %>
-  #
-  #  # Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
-  #  <%= render "account", :account => @buyer %>
-  #
-  #  # @account is an Account instance, so it uses the RecordIdentifier to replace
-  #  # <%= render :partial => "accounts/account", :locals => { :account => @account } %>
-  #  <%= render(@account) %>
-  #
-  #  # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
-  #  # <%= render :partial => "posts/post", :collection => @posts %>
-  #  <%= render(@posts) %>
-  #
-  # == Rendering partials with layouts
-  #
-  # Partials can have their own layouts applied to them. These layouts are different than the ones that are
-  # specified globally for the entire action, but they work in a similar fashion. Imagine a list with two types
-  # of users:
-  #
-  #   <%# app/views/users/index.html.erb &>
-  #   Here's the administrator:
-  #   <%= render :partial => "user", :layout => "administrator", :locals => { :user => administrator } %>
-  #
-  #   Here's the editor:
-  #   <%= render :partial => "user", :layout => "editor", :locals => { :user => editor } %>
-  #
-  #   <%# app/views/users/_user.html.erb &>
-  #   Name: <%= user.name %>
-  #
-  #   <%# app/views/users/_administrator.html.erb &>
-  #   <div id="administrator">
-  #     Budget: $<%= user.budget %>
-  #     <%= yield %>
-  #   </div>
-  #
-  #   <%# app/views/users/_editor.html.erb &>
-  #   <div id="editor">
-  #     Deadline: <%= user.deadline %>
-  #     <%= yield %>
-  #   </div>
-  #
-  # ...this will return:
-  #
-  #   Here's the administrator:
-  #   <div id="administrator">
-  #     Budget: $<%= user.budget %>
-  #     Name: <%= user.name %>
-  #   </div>
-  #
-  #   Here's the editor:
-  #   <div id="editor">
-  #     Deadline: <%= user.deadline %>
-  #     Name: <%= user.name %>
-  #   </div>
-  #
-  # You can also apply a layout to a block within any template:
-  #
-  #   <%# app/views/users/_chief.html.erb &>
-  #   <%= render(:layout => "administrator", :locals => { :user => chief }) do %>
-  #     Title: <%= chief.title %>
-  #   <% end %>
-  #
-  # ...this will return:
-  #
-  #   <div id="administrator">
-  #     Budget: $<%= user.budget %>
-  #     Title: <%= chief.name %>
-  #   </div>
-  #
-  # As you can see, the <tt>:locals</tt> hash is shared between both the partial and its layout.
-  #
-  # If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass
-  # an array to layout and treat it as an enumerable.
-  #
-  #   <%# app/views/users/_user.html.erb &>
-  #   <div class="user">
-  #     Budget: $<%= user.budget %>
-  #     <%= yield user %>
-  #   </div>
-  #
-  #   <%# app/views/users/index.html.erb &>
-  #   <%= render :layout => @users do |user| %>
-  #     Title: <%= user.title %>
-  #   <% end %>
-  #
-  # This will render the layout for each user and yield to the block, passing the user, each time.
-  #
-  # You can also yield multiple times in one layout and use block arguments to differentiate the sections.
-  #
-  #   <%# app/views/users/_user.html.erb &>
-  #   <div class="user">
-  #     <%= yield user, :header %>
-  #     Budget: $<%= user.budget %>
-  #     <%= yield user, :footer %>
-  #   </div>
-  #
-  #   <%# app/views/users/index.html.erb &>
-  #   <%= render :layout => @users do |user, section| %>
-  #     <%- case section when :header -%>
-  #       Title: <%= user.title %>
-  #     <%- when :footer -%>
-  #       Deadline: <%= user.deadline %>
-  #     <%- end -%>
-  #   <% end %>
-  module Partials
-    def _render_partial(options, &block) #:nodoc:
-      _partial_renderer.setup(options, block).render
-    end
-
-    def _partial_renderer #:nodoc:
-      @_partial_renderer ||= PartialRenderer.new(self)
-    end
-  end
-end
diff --git a/actionpack/lib/action_view/railtie.rb b/actionpack/lib/action_view/railtie.rb
index f20ba7e6d3..80391d72cc 100644
--- a/actionpack/lib/action_view/railtie.rb
+++ b/actionpack/lib/action_view/railtie.rb
@@ -6,7 +6,7 @@ module ActionView
   class Railtie < Rails::Railtie
     config.action_view = ActiveSupport::OrderedOptions.new
     config.action_view.stylesheet_expansions = {}
-    config.action_view.javascript_expansions = { :defaults => %w(jquery rails) }
+    config.action_view.javascript_expansions = { :defaults => %w(jquery jquery_ujs) }
 
     initializer "action_view.cache_asset_ids" do |app|
       unless app.config.cache_classes
diff --git a/actionpack/lib/action_view/renderer/abstract_renderer.rb b/actionpack/lib/action_view/renderer/abstract_renderer.rb
index 4a52b3172e..60c527beeb 100644
--- a/actionpack/lib/action_view/renderer/abstract_renderer.rb
+++ b/actionpack/lib/action_view/renderer/abstract_renderer.rb
@@ -3,9 +3,8 @@ module ActionView
     delegate :find_template, :template_exists?, :with_fallbacks, :update_details,
       :with_layout_format, :formats, :freeze_formats, :to => :@lookup_context
 
-    def initialize(view)
-      @view = view
-      @lookup_context = view.lookup_context
+    def initialize(lookup_context)
+      @lookup_context = lookup_context
     end
 
     def render
diff --git a/actionpack/lib/action_view/renderer/partial_renderer.rb b/actionpack/lib/action_view/renderer/partial_renderer.rb
index 10cd37d56f..a351fbc04f 100644
--- a/actionpack/lib/action_view/renderer/partial_renderer.rb
+++ b/actionpack/lib/action_view/renderer/partial_renderer.rb
@@ -1,44 +1,230 @@
+require 'active_support/core_ext/object/blank'
+
 module ActionView
+  # = Action View Partials
+  #
+  # There's also a convenience method for rendering sub templates within the current controller that depends on a
+  # single object (we call this kind of sub templates for partials). It relies on the fact that partials should
+  # follow the naming convention of being prefixed with an underscore -- as to separate them from regular
+  # templates that could be rendered on their own.
+  #
+  # In a template for Advertiser#account:
+  #
+  #  <%= render :partial => "account" %>
+  #
+  # This would render "advertiser/_account.html.erb" and pass the instance variable @account in as a local variable
+  # +account+ to the template for display.
+  #
+  # In another template for Advertiser#buy, we could have:
+  #
+  #   <%= render :partial => "account", :locals => { :account => @buyer } %>
+  #
+  #   <% @advertisements.each do |ad| %>
+  #     <%= render :partial => "ad", :locals => { :ad => ad } %>
+  #   <% end %>
+  #
+  # This would first render "advertiser/_account.html.erb" with @buyer passed in as the local variable +account+, then
+  # render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display.
+  #
+  # == The :as and :object options
+  #
+  # By default <tt>ActionView::Partials::PartialRenderer</tt> has its object in a local variable with the same
+  # name as the template. So, given
+  #
+  #   <%= render :partial => "contract" %>
+  #
+  # within contract we'll get <tt>@contract</tt> in the local variable +contract+, as if we had written
+  #
+  #   <%= render :partial => "contract", :locals => { :contract  => @contract } %>
+  #
+  # With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we
+  # wanted it to be +agreement+ instead of +contract+ we'd do:
+  #
+  #   <%= render :partial => "contract", :as => 'agreement' %>
+  #
+  # The <tt>:object</tt> option can be used to directly specify which object is rendered into the partial;
+  # useful when the template's object is elsewhere, in a different ivar or in a local variable for instance.
+  #
+  # Revisiting a previous example we could have written this code:
+  #
+  #   <%= render :partial => "account", :object => @buyer %>
+  #
+  #   <% @advertisements.each do |ad| %>
+  #     <%= render :partial => "ad", :object => ad %>
+  #   <% end %>
+  #
+  # The <tt>:object</tt> and <tt>:as</tt> options can be used together.
+  #
+  # == Rendering a collection of partials
+  #
+  # The example of partial use describes a familiar pattern where a template needs to iterate over an array and
+  # render a sub template for each of the elements. This pattern has been implemented as a single method that
+  # accepts an array and renders a partial by the same name as the elements contained within. So the three-lined
+  # example in "Using partials" can be rewritten with a single line:
+  #
+  #   <%= render :partial => "ad", :collection => @advertisements %>
+  #
+  # This will render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display. An
+  # iteration counter will automatically be made available to the template with a name of the form
+  # +partial_name_counter+. In the case of the example above, the template would be fed +ad_counter+.
+  #
+  # The <tt>:as</tt> option may be used when rendering partials.
+  #
+  # You can specify a partial to be rendered between elements via the <tt>:spacer_template</tt> option.
+  # The following example will render <tt>advertiser/_ad_divider.html.erb</tt> between each ad partial:
+  #
+  #   <%= render :partial => "ad", :collection => @advertisements, :spacer_template => "ad_divider" %>
+  #
+  # If the given <tt>:collection</tt> is nil or empty, <tt>render</tt> will return nil. This will allow you
+  # to specify a text which will displayed instead by using this form:
+  #
+  #   <%= render(:partial => "ad", :collection => @advertisements) || "There's no ad to be displayed" %>
+  #
+  # NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also
+  # just keep domain objects, like Active Records, in there.
+  #
+  # == Rendering shared partials
+  #
+  # Two controllers can share a set of partials and render them like this:
+  #
+  #   <%= render :partial => "advertisement/ad", :locals => { :ad => @advertisement } %>
+  #
+  # This will render the partial "advertisement/_ad.html.erb" regardless of which controller this is being called from.
+  #
+  # == Rendering objects with the RecordIdentifier
+  #
+  # Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if
+  # you're following its conventions for RecordIdentifier#partial_path. Examples:
+  #
+  #  # @account is an Account instance, so it uses the RecordIdentifier to replace
+  #  # <%= render :partial => "accounts/account", :locals => { :account => @account} %>
+  #  <%= render :partial => @account %>
+  #
+  #  # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
+  #  # <%= render :partial => "posts/post", :collection => @posts %>
+  #  <%= render :partial => @posts %>
+  #
+  # == Rendering the default case
+  #
+  # If you're not going to be using any of the options like collections or layouts, you can also use the short-hand
+  # defaults of render to render partials. Examples:
+  #
+  #  # Instead of <%= render :partial => "account" %>
+  #  <%= render "account" %>
+  #
+  #  # Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
+  #  <%= render "account", :account => @buyer %>
+  #
+  #  # @account is an Account instance, so it uses the RecordIdentifier to replace
+  #  # <%= render :partial => "accounts/account", :locals => { :account => @account } %>
+  #  <%= render(@account) %>
+  #
+  #  # @posts is an array of Post instances, so it uses the RecordIdentifier to replace
+  #  # <%= render :partial => "posts/post", :collection => @posts %>
+  #  <%= render(@posts) %>
+  #
+  # == Rendering partials with layouts
+  #
+  # Partials can have their own layouts applied to them. These layouts are different than the ones that are
+  # specified globally for the entire action, but they work in a similar fashion. Imagine a list with two types
+  # of users:
+  #
+  #   <%# app/views/users/index.html.erb &>
+  #   Here's the administrator:
+  #   <%= render :partial => "user", :layout => "administrator", :locals => { :user => administrator } %>
+  #
+  #   Here's the editor:
+  #   <%= render :partial => "user", :layout => "editor", :locals => { :user => editor } %>
+  #
+  #   <%# app/views/users/_user.html.erb &>
+  #   Name: <%= user.name %>
+  #
+  #   <%# app/views/users/_administrator.html.erb &>
+  #   <div id="administrator">
+  #     Budget: $<%= user.budget %>
+  #     <%= yield %>
+  #   </div>
+  #
+  #   <%# app/views/users/_editor.html.erb &>
+  #   <div id="editor">
+  #     Deadline: <%= user.deadline %>
+  #     <%= yield %>
+  #   </div>
+  #
+  # ...this will return:
+  #
+  #   Here's the administrator:
+  #   <div id="administrator">
+  #     Budget: $<%= user.budget %>
+  #     Name: <%= user.name %>
+  #   </div>
+  #
+  #   Here's the editor:
+  #   <div id="editor">
+  #     Deadline: <%= user.deadline %>
+  #     Name: <%= user.name %>
+  #   </div>
+  #
+  # You can also apply a layout to a block within any template:
+  #
+  #   <%# app/views/users/_chief.html.erb &>
+  #   <%= render(:layout => "administrator", :locals => { :user => chief }) do %>
+  #     Title: <%= chief.title %>
+  #   <% end %>
+  #
+  # ...this will return:
+  #
+  #   <div id="administrator">
+  #     Budget: $<%= user.budget %>
+  #     Title: <%= chief.name %>
+  #   </div>
+  #
+  # As you can see, the <tt>:locals</tt> hash is shared between both the partial and its layout.
+  #
+  # If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass
+  # an array to layout and treat it as an enumerable.
+  #
+  #   <%# app/views/users/_user.html.erb &>
+  #   <div class="user">
+  #     Budget: $<%= user.budget %>
+  #     <%= yield user %>
+  #   </div>
+  #
+  #   <%# app/views/users/index.html.erb &>
+  #   <%= render :layout => @users do |user| %>
+  #     Title: <%= user.title %>
+  #   <% end %>
+  #
+  # This will render the layout for each user and yield to the block, passing the user, each time.
+  #
+  # You can also yield multiple times in one layout and use block arguments to differentiate the sections.
+  #
+  #   <%# app/views/users/_user.html.erb &>
+  #   <div class="user">
+  #     <%= yield user, :header %>
+  #     Budget: $<%= user.budget %>
+  #     <%= yield user, :footer %>
+  #   </div>
+  #
+  #   <%# app/views/users/index.html.erb &>
+  #   <%= render :layout => @users do |user, section| %>
+  #     <%- case section when :header -%>
+  #       Title: <%= user.title %>
+  #     <%- when :footer -%>
+  #       Deadline: <%= user.deadline %>
+  #     <%- end -%>
+  #   <% end %>
   class PartialRenderer < AbstractRenderer #:nodoc:
     PARTIAL_NAMES = Hash.new {|h,k| h[k] = {} }
 
-    def initialize(view)
+    def initialize(*)
       super
-      @partial_names = PARTIAL_NAMES[@view.controller.class.name]
+      @partial_names = PARTIAL_NAMES[@lookup_context.prefixes.first]
     end
 
-    def setup(options, block)
-      partial = options[:partial]
-
-      @options = options
-      @locals  = options[:locals] || {}
-      @block   = block
-
-      if String === partial
-        @object     = options[:object]
-        @path       = partial
-        @collection = collection
-      else
-        @object = partial
-
-        if @collection = collection_from_object || collection
-          paths = @collection_data = @collection.map { |o| partial_path(o) }
-          @path = paths.uniq.size == 1 ? paths.first : nil
-        else
-          @path = partial_path
-        end
-      end
-
-      if @path
-        @variable, @variable_counter = retrieve_variable(@path)
-      else
-        paths.map! { |path| retrieve_variable(path).unshift(path) }
-      end
-
-      self
-    end
+    def render(context, options, block)
+      setup(context, options, block)
 
-    def render
       wrap_formats(@path) do
         identifier = ((@template = find_partial) ? @template.identifier : @path)
 
@@ -77,7 +263,7 @@ module ActionView
       locals[as] = object
 
       content = @template.render(view, locals) do |*name|
-        view._block_layout_for(*name, &block)
+        view._layout_for(*name, &block)
       end
 
       content = layout.render(view, locals){ content } if layout
@@ -86,6 +272,38 @@ module ActionView
 
     private
 
+    def setup(context, options, block)
+      @view   = context
+      partial = options[:partial]
+
+      @options = options
+      @locals  = options[:locals] || {}
+      @block   = block
+
+      if String === partial
+        @object     = options[:object]
+        @path       = partial
+        @collection = collection
+      else
+        @object = partial
+
+        if @collection = collection_from_object || collection
+          paths = @collection_data = @collection.map { |o| partial_path(o) }
+          @path = paths.uniq.size == 1 ? paths.first : nil
+        else
+          @path = partial_path
+        end
+      end
+
+      if @path
+        @variable, @variable_counter = retrieve_variable(@path)
+      else
+        paths.map! { |path| retrieve_variable(path).unshift(path) }
+      end
+
+      self
+    end
+
     def collection
       if @options.key?(:collection)
         collection = @options[:collection]
@@ -109,7 +327,7 @@ module ActionView
     end
 
     def find_template(path=@path, locals=@locals.keys)
-      prefixes = path.include?(?/) ? [] : @view.controller_prefixes
+      prefixes = path.include?(?/) ? [] : @lookup_context.prefixes
       @lookup_context.find_template(path, prefixes, true, locals)
     end
 
@@ -150,7 +368,7 @@ module ActionView
         object = object.to_model if object.respond_to?(:to_model)
 
         object.class.model_name.partial_path.dup.tap do |partial|
-          path = @view.controller_prefixes.first
+          path = @lookup_context.prefixes.first
           partial.insert(0, "#{File.dirname(path)}/") if partial.include?(?/) && path.include?(?/)
         end
       end
diff --git a/actionpack/lib/action_view/renderer/renderer.rb b/actionpack/lib/action_view/renderer/renderer.rb
new file mode 100644
index 0000000000..bf1b5a7d22
--- /dev/null
+++ b/actionpack/lib/action_view/renderer/renderer.rb
@@ -0,0 +1,54 @@
+module ActionView
+  # This is the main entry point for rendering. It basically delegates
+  # to other objects like TemplateRenderer and PartialRenderer which
+  # actually renders the template.
+  class Renderer
+    attr_accessor :lookup_context
+
+    def initialize(lookup_context)
+      @lookup_context = lookup_context
+    end
+
+    # Main render entry point shared by AV and AC.
+    def render(context, options)
+      if options.key?(:partial)
+        render_partial(context, options)
+      else
+        render_template(context, options)
+      end
+    end
+
+    # Render but returns a valid Rack body. If fibers are defined, we return
+    # a streaming body that renders the template piece by piece.
+    #
+    # Note that partials are not supported to be rendered with streaming,
+    # so in such cases, we just wrap them in an array.
+    def render_body(context, options)
+      if options.key?(:partial)
+        [render_partial(context, options)]
+      else
+        StreamingTemplateRenderer.new(@lookup_context).render(context, options)
+      end
+    end
+
+    # Direct accessor to template rendering.
+    def render_template(context, options) #:nodoc:
+      _template_renderer.render(context, options)
+    end
+
+    # Direct access to partial rendering.
+    def render_partial(context, options, &block) #:nodoc:
+      _partial_renderer.render(context, options, block)
+    end
+
+    private
+
+    def _template_renderer #:nodoc:
+      @_template_renderer ||= TemplateRenderer.new(@lookup_context)
+    end
+
+    def _partial_renderer #:nodoc:
+      @_partial_renderer ||= PartialRenderer.new(@lookup_context)
+    end
+  end
+end
diff --git a/actionpack/lib/action_view/renderer/streaming_template_renderer.rb b/actionpack/lib/action_view/renderer/streaming_template_renderer.rb
index 52f0e9f5bd..1ccf5a8ddb 100644
--- a/actionpack/lib/action_view/renderer/streaming_template_renderer.rb
+++ b/actionpack/lib/action_view/renderer/streaming_template_renderer.rb
@@ -4,53 +4,11 @@
 require 'fiber' if defined?(Fiber)
 
 module ActionView
-  # Consider the following layout:
-  # 
-  #   <%= yield :header %>
-  #   2
-  #   <%= yield %>
-  #   5
-  #   <%= yield :footer %>
-  #
-  # And template:
-  #
-  #     <%= provide :header, "1" %>
-  #     3
-  #     4
-  #     <%= provide :footer, "6" %>
-  # 
-  # It will stream:
-  # 
-  #     "1\n", "2\n", "3\n4\n", "5\n", "6\n"
-  #
-  # Notice that once you <%= yield %>, it will render the whole template
-  # before streaming again. In the future, we can also support streaming
-  # from the template and not only the layout.
-  #
-  # Also, notice we use +provide+ instead of +content_for+, as +provide+
-  # gives the control back to the layout as soon as it is called.
-  # With +content_for+, it would render all the template to find all
-  # +content_for+ calls. For instance, consider this layout:
-  #
-  #   <%= yield :header %>
-  #
-  # With this template:
-  #
-  #   <%= content_for :header, "1" %>
-  #   <%= provide :header, "2" %>
-  #   <%= provide :header, "3" %>
-  #
-  # It will return "12\n" because +content_for+ continues rendering the
-  # template but it is returns back to the layout as soon as it sees the
-  # first +provide+.
-  #
   # == TODO
   #
-  # * Add streaming support in the controllers with no-cache settings
-  # * What should happen when an error happens?
   # * Support streaming from child templates, partials and so on.
-  # * Support on sprockets async JS load?
-  #
+  # * Integrate exceptions with exceptron
+  # * Rack::Cache needs to support streaming bodies
   class StreamingTemplateRenderer < TemplateRenderer #:nodoc:
     # A valid Rack::Body (i.e. it responds to each).
     # It is initialized with a block that, when called, starts
@@ -61,9 +19,28 @@ module ActionView
       end
 
       def each(&block)
-        @start.call(block)
+        begin
+          @start.call(block)
+        rescue Exception => exception
+          log_error(exception)
+          block.call ActionView::Base.streaming_completion_on_exception
+        end
         self
       end
+
+      private
+
+      # This is the same logging logic as in ShowExceptions middleware.
+      # TODO Once "exceptron" is in, refactor this piece to simply re-use exceptron.
+      def log_error(exception) #:nodoc:
+        logger = ActionController::Base.logger
+        return unless logger
+
+        message = "\n#{exception.class} (#{exception.message}):\n"
+        message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
+        message << "  " << exception.backtrace.join("\n  ")
+        logger.fatal("#{message}\n\n")
+      end
     end
 
     # For streaming, instead of rendering a given a template, we return a Body
@@ -105,7 +82,7 @@ module ActionView
         # Set the view flow to support streaming. It will be aware
         # when to stop rendering the layout because it needs to search
         # something in the template and vice-versa.
-        view._view_flow = StreamingFlow.new(view, fiber)
+        view.view_flow = StreamingFlow.new(view, fiber)
 
         # Yo! Start the fiber!
         fiber.resume
@@ -117,7 +94,7 @@ module ActionView
           content = template.render(view, locals, &yielder)
 
           # Once rendering the template is done, sets its content in the :layout key.
-          view._view_flow.set(:layout, content)
+          view.view_flow.set(:layout, content)
 
           # In case the layout continues yielding, we need to resume
           # the fiber until all yields are handled.
diff --git a/actionpack/lib/action_view/renderer/template_renderer.rb b/actionpack/lib/action_view/renderer/template_renderer.rb
index 6b5ead463f..a09cef8fef 100644
--- a/actionpack/lib/action_view/renderer/template_renderer.rb
+++ b/actionpack/lib/action_view/renderer/template_renderer.rb
@@ -3,7 +3,9 @@ require 'active_support/core_ext/array/wrap'
 
 module ActionView
   class TemplateRenderer < AbstractRenderer #:nodoc:
-    def render(options)
+    def render(context, options)
+      @view = context
+
       wrap_formats(options[:template] || options[:file]) do
         template = determine_template(options)
         freeze_formats(template.formats, true)
@@ -18,7 +20,7 @@ module ActionView
       if options.key?(:text)
         Template::Text.new(options[:text], formats.try(:first))
       elsif options.key?(:file)
-        with_fallbacks { find_template(options[:file], options[:prefixes], false, keys) }
+        with_fallbacks { find_template(options[:file], nil, false, keys) }
       elsif options.key?(:inline)
         handler = Template.handler_for_extension(options[:type] || "erb")
         Template.new(options[:inline], "inline template", handler, :locals => keys)
@@ -46,7 +48,7 @@ module ActionView
 
       if layout
         view = @view
-        view._view_flow.set(:layout, content)
+        view.view_flow.set(:layout, content)
         layout.render(view, locals){ |*name| view._layout_for(*name) }
       else
         content
diff --git a/actionpack/lib/action_view/rendering.rb b/actionpack/lib/action_view/rendering.rb
deleted file mode 100644
index 2bce2fb045..0000000000
--- a/actionpack/lib/action_view/rendering.rb
+++ /dev/null
@@ -1,114 +0,0 @@
-require 'active_support/core_ext/object/try'
-
-module ActionView
-  # = Action View Rendering
-  module Rendering
-    # Returns the result of a render that's dictated by the options hash. The primary options are:
-    #
-    # * <tt>:partial</tt> - See ActionView::Partials.
-    # * <tt>:file</tt> - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
-    # * <tt>:inline</tt> - Renders an inline template similar to how it's done in the controller.
-    # * <tt>:text</tt> - Renders the text passed in out.
-    #
-    # If no options hash is passed or :update specified, the default is to render a partial and use the second parameter
-    # as the locals hash.
-    def render(options = {}, locals = {}, &block)
-      case options
-      when Hash
-        if block_given?
-          _render_partial(options.merge(:partial => options[:layout]), &block)
-        elsif options.key?(:partial)
-          _render_partial(options)
-        else
-          _render_template(options)
-        end
-      else
-        _render_partial(:partial => options, :locals => locals)
-      end
-    end
-
-    # Render but returns a valid Rack body. If fibers are defined, we return
-    # a streaming body that renders the template piece by piece.
-    #
-    # Note that partials are not supported to be rendered with streaming,
-    # so in such cases, we just wrap them in an array.
-    def render_body(options)
-      if options.key?(:partial)
-        [_render_partial(options)]
-      else
-        StreamingTemplateRenderer.new(self).render(options)
-      end
-    end
-
-    # Returns the contents that are yielded to a layout, given a name or a block.
-    #
-    # You can think of a layout as a method that is called with a block. If the user calls
-    # <tt>yield :some_name</tt>, the block, by default, returns <tt>content_for(:some_name)</tt>.
-    # If the user calls simply +yield+, the default block returns <tt>content_for(:layout)</tt>.
-    #
-    # The user can override this default by passing a block to the layout:
-    #
-    #   # The template
-    #   <%= render :layout => "my_layout" do %>
-    #     Content
-    #   <% end %>
-    #
-    #   # The layout
-    #   <html>
-    #     <%= yield %>
-    #   </html>
-    #
-    # In this case, instead of the default block, which would return <tt>content_for(:layout)</tt>,
-    # this method returns the block that was passed in to <tt>render :layout</tt>, and the response
-    # would be
-    #
-    #   <html>
-    #     Content
-    #   </html>
-    #
-    # Finally, the block can take block arguments, which can be passed in by +yield+:
-    #
-    #   # The template
-    #   <%= render :layout => "my_layout" do |customer| %>
-    #     Hello <%= customer.name %>
-    #   <% end %>
-    #
-    #   # The layout
-    #   <html>
-    #     <%= yield Struct.new(:name).new("David") %>
-    #   </html>
-    #
-    # In this case, the layout would receive the block passed into <tt>render :layout</tt>,
-    # and the struct specified would be passed into the block as an argument. The result
-    # would be
-    #
-    #   <html>
-    #     Hello David
-    #   </html>
-    #
-    def _layout_for(*args)
-      name = args.first
-      name = :layout unless name.is_a?(Symbol)
-      @_view_flow.get(name).html_safe
-    end
-
-    # Handle layout for calls from partials that supports blocks.
-    def _block_layout_for(*args, &block)
-      name = args.first
-
-      if !name.is_a?(Symbol) && block
-        capture(*args, &block)
-      else
-        _layout_for(*args)
-      end
-    end
-
-    def _render_template(options) #:nodoc:
-      _template_renderer.render(options)
-    end
-
-    def _template_renderer #:nodoc:
-      @_template_renderer ||= TemplateRenderer.new(self)
-    end
-  end
-end
diff --git a/actionpack/lib/action_view/template.rb b/actionpack/lib/action_view/template.rb
index 6dfc4f68ae..98ecd15aa0 100644
--- a/actionpack/lib/action_view/template.rb
+++ b/actionpack/lib/action_view/template.rb
@@ -139,15 +139,12 @@ module ActionView
     # we use a bang in this instrumentation because you don't want to
     # consume this in production. This is only slow if it's being listened to.
     def render(view, locals, buffer=nil, &block)
-      old_template, view._template = view._template, self
       ActiveSupport::Notifications.instrument("!render_template.action_view", :virtual_path => @virtual_path) do
         compile!(view)
         view.send(method_name, locals, buffer, &block)
       end
     rescue Exception => e
       handle_render_error(view, e)
-    ensure
-      view._template = old_template
     end
 
     def mime_type
@@ -174,12 +171,7 @@ module ActionView
     end
 
     def inspect
-      @inspect ||=
-        if defined?(Rails.root)
-          identifier.sub("#{Rails.root}/", '')
-        else
-          identifier
-        end
+      @inspect ||= defined?(Rails.root) ? identifier.sub("#{Rails.root}/", '') : identifier
     end
 
     protected
@@ -264,9 +256,9 @@ module ActionView
         # encoding of the code
         source = <<-end_src
           def #{method_name}(local_assigns, output_buffer)
-            _old_output_buffer = @output_buffer;#{locals_code};#{code}
+            _old_virtual_path, @virtual_path = @virtual_path, #{@virtual_path.inspect};_old_output_buffer = @output_buffer;#{locals_code};#{code}
           ensure
-            @output_buffer = _old_output_buffer
+            @virtual_path, @output_buffer = _old_virtual_path, _old_output_buffer
           end
         end_src
 
diff --git a/actionpack/lib/action_view/test_case.rb b/actionpack/lib/action_view/test_case.rb
index 5c74bf843a..d0317a148b 100644
--- a/actionpack/lib/action_view/test_case.rb
+++ b/actionpack/lib/action_view/test_case.rb
@@ -1,4 +1,6 @@
 require 'active_support/core_ext/object/blank'
+require 'active_support/core_ext/module/delegation'
+require 'active_support/core_ext/module/remove_method'
 require 'action_controller'
 require 'action_controller/test_case'
 require 'action_view'
@@ -43,6 +45,7 @@ module ActionView
       include AbstractController::Helpers
       include ActionView::Helpers
 
+      delegate :lookup_context, :to => :controller
       attr_accessor :controller, :output_buffer, :rendered
 
       module ClassMethods
@@ -127,7 +130,7 @@ module ActionView
 
       def say_no_to_protect_against_forgery!
         _helpers.module_eval do
-          remove_method :protect_against_forgery? if method_defined?(:protect_against_forgery?)
+          remove_possible_method :protect_against_forgery?
           def protect_against_forgery?
             false
           end
@@ -147,9 +150,19 @@ module ActionView
       module Locals
         attr_accessor :locals
 
-        def _render_partial(options)
-          locals[options[:partial]] = options[:locals]
-          super(options)
+        def render(options = {}, local_assigns = {})
+          case options
+          when Hash
+            if block_given?
+              locals[options[:layout]] = options[:locals]
+            elsif options.key?(:partial)
+              locals[options[:partial]] = options[:locals]
+            end
+          else
+            locals[options] = local_assigns
+          end
+
+          super
         end
       end
 
diff --git a/actionpack/lib/sprockets/railtie.rb b/actionpack/lib/sprockets/railtie.rb
index fe3c8c9783..9c10decd60 100644
--- a/actionpack/lib/sprockets/railtie.rb
+++ b/actionpack/lib/sprockets/railtie.rb
@@ -32,6 +32,13 @@ module Sprockets
       next unless assets.enabled
 
       app.assets = asset_environment(app)
+
+      ActiveSupport.on_load(:action_view) do
+        app.assets.context.instance_eval do
+          include ::ActionView::Helpers::SprocketsHelper
+        end
+      end
+
       app.routes.append do
         mount app.assets => assets.prefix
       end
@@ -50,7 +57,44 @@ module Sprockets
       env.static_root = File.join(app.root.join("public"), assets.prefix)
       env.paths.concat assets.paths
       env.logger = Rails.logger
+      env.js_compressor = expand_js_compressor(assets.js_compressor)
+      env.css_compressor = expand_css_compressor(assets.css_compressor)
       env
     end
+
+    def expand_js_compressor(sym)
+      case sym
+      when :closure
+        require 'closure-compiler'
+        Closure::Compiler.new
+      when :uglifier
+        require 'uglifier'
+        Uglifier.new
+      when :yui
+        require 'yui/compressor'
+        YUI::JavaScriptCompressor.new
+      else
+        sym
+      end
+    end
+
+    def expand_css_compressor(sym)
+      case sym
+      when :scss
+        require 'sass'
+        compressor = Object.new
+        def compressor.compress(source)
+          Sass::Engine.new(source,
+            :syntax => :scss, :style => :compressed
+          ).render
+        end
+        compressor
+      when :yui
+        require 'yui/compressor'
+        YUI::JavaScriptCompressor.new(:munge => true)
+      else
+        sym
+      end
+    end
   end
-end
\ No newline at end of file
+end