2 files changed, 60 insertions, 17 deletions

diff --git a/actionpack/lib/abstract_controller/base.rb b/actionpack/lib/abstract_controller/base.rb
index a84ed17bd4..af5de815bb 100644
--- a/actionpack/lib/abstract_controller/base.rb
+++ b/actionpack/lib/abstract_controller/base.rb
@@ -114,11 +114,6 @@ module AbstractController
       end
     end
 
-    # Define some internal variables that should not be propagated to the view.
-    def self.default_protected_instance_vars
-      []
-    end
-
     abstract!
 
     # Calls the action going through the entire action dispatch stack.
diff --git a/actionpack/lib/abstract_controller/rendering.rb b/actionpack/lib/abstract_controller/rendering.rb
index 41f19fba78..4596aad46c 100644
--- a/actionpack/lib/abstract_controller/rendering.rb
+++ b/actionpack/lib/abstract_controller/rendering.rb
@@ -13,8 +13,15 @@ module AbstractController
   module Rendering
     extend ActiveSupport::Concern
 
-    def self.default_protected_instance_vars
-      super.concat [:@_action_name, :@_response_body, :@_formats, :@_prefixes, :@_config]
+    included do
+      class_attribute :protected_instance_variables
+      self.protected_instance_variables = []
+    end
+
+    # Normalize arguments, options and then delegates render_to_body and
+    # sticks the result in self.response_body.
+    # :api: public
+    def render(*args, &block)
     end
 
     # Raw rendering of a template to a string.
@@ -29,32 +36,37 @@ module AbstractController
     # overridden in order to still return a string.
     # :api: plugin
     def render_to_string(*args, &block)
+      options = _normalize_render(*args, &block)
+      render_to_body(options)
     end
 
     # Raw rendering of a template.
-    # :api: plugin
-    def render_to_body(options = {})
-    end
-
-    # Normalize arguments, options and then delegates render_to_body and
-    # sticks the result in self.response_body.
     # :api: public
-    def render(*args, &block)
+    def render_to_body(options = {})
+      _process_options(options)
+      _render_template(options)
     end
 
     # Return Content-Type of rendered content
     # :api: public
     def rendered_format
+      Mime::TEXT
     end
 
+    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 = {}
-      (instance_variables - self.class.default_protected_instance_vars).each do |name|
-        hash[name[1..-1]] = instance_variable_get(name)
-      end
+      variables  = instance_variables
+      variables -= protected_instance_variables
+      variables -= DEFAULT_PROTECTED_INSTANCE_VARIABLES
+      variables.each { |name| hash[name[1..-1]] = instance_variable_get(name) }
       hash
     end
 
@@ -76,5 +88,41 @@ module AbstractController
     def _process_options(options)
       options
     end
+
+    # Normalize args and options.
+    # :api: private
+    def _normalize_render(*args, &block)
+      options = _normalize_args(*args, &block)
+      _normalize_options(options)
+      options
+    end
+  end
+
+  # Basic rendering implements the most minimal rendering layer.
+  # It only supports rendering :text and :nothing. Passing any other option will
+  # result in `UnsupportedOperationError` exception. For more functionality like
+  # different formats, layouts etc. you should use `ActionView` gem.
+  module BasicRendering
+    extend ActiveSupport::Concern
+
+    # Render text or nothing (empty string) to response_body
+    # :api: public
+    def render(*args, &block)
+      super(*args, &block)
+      opts = args.first
+      if opts.has_key?(:text) && opts[:text].present?
+        self.response_body = opts[:text]
+      elsif opts.has_key?(:nothing) && opts[:nothing]
+        self.response_body = " "
+      else
+        raise UnsupportedOperationError
+      end
+    end
+
+    class UnsupportedOperationError < StandardError
+      def initialize
+        super "Unsupported render operation. BasicRendering supports only :text and :nothing options. For more, you need to include ActionView."
+      end
+    end
   end
 end