Add `#no_content_type` attribute to `AD::Response`

Setting this attribute to `true` will remove the content type header
from the request. This is use in `render :body` feature.

actionpack/lib/action_controller/metal/rack_delegation.rb

@@ -5,8 +5,8 @@ module ActionController
   module RackDelegation
     extend ActiveSupport::Concern
 
-    delegate :headers, :status=, :location=, :content_type=,
-             :status, :location, :content_type, :to => "@_response"
+    delegate :headers, :status=, :location=, :content_type=, :no_content_type=,
+             :status, :location, :content_type, :no_content_type, :to => "@_response"
 
     def dispatch(action, request)
       set_response!(request)

actionpack/lib/action_controller/metal/rendering.rb

@@ -44,15 +44,13 @@ module ActionController
 
     def _process_format(format, options = {})
       super
-      self.content_type ||= format.to_s
 
-      if options[:body].present?
-        self.content_type = "none"
+      if options[:body]
         self.headers.delete "Content-Type"
-      end
-
-      if options[:plain].present?
+      elsif options[:plain]
         self.content_type = Mime::TEXT
+      else
+        self.content_type ||= format.to_s
       end
     end
 

actionpack/lib/action_dispatch/http/response.rb

@@ -63,6 +63,8 @@ module ActionDispatch # :nodoc:
     # content you're giving them, so we need to send that along.
     attr_accessor :charset
 
+    attr_accessor :no_content_type # :nodoc:
+
     CONTENT_TYPE = "Content-Type".freeze
     SET_COOKIE   = "Set-Cookie".freeze
     LOCATION     = "Location".freeze
@@ -288,7 +290,7 @@ module ActionDispatch # :nodoc:
     end
 
     def assign_default_content_type_and_charset!(headers)
-      return if headers[CONTENT_TYPE].present? || @content_type == "none"
+      return if headers[CONTENT_TYPE].present?
 
       @content_type ||= Mime::HTML
       @charset      ||= self.class.default_charset unless @charset == false
@@ -303,8 +305,17 @@ module ActionDispatch # :nodoc:
       !@sending_file && @charset != false
     end
 
+    def remove_content_type!
+      headers.delete CONTENT_TYPE
+    end
+
     def rack_response(status, header)
-      assign_default_content_type_and_charset!(header)
+      if no_content_type
+        remove_content_type!
+      else
+        assign_default_content_type_and_charset!(header)
+      end
+
       handle_conditional_get!
 
       header[SET_COOKIE] = header[SET_COOKIE].join("\n") if header[SET_COOKIE].respond_to?(:join)

actionpack/test/dispatch/response_test.rb

@@ -238,7 +238,7 @@ class ResponseTest < ActiveSupport::TestCase
 
   test "does not add default content-type if Content-Type is none" do
     resp = ActionDispatch::Response.new.tap { |response|
-      response.content_type = 'none'
+      response.no_content_type = true
     }
 
     assert_not resp.headers.has_key?('Content-Type')

actionview/lib/action_view/rendering.rb

@@ -102,6 +102,11 @@ module ActionView
       # Assign the rendered format to lookup context.
       def _process_format(format, options = {}) #:nodoc:
         super
+
+        if options[:body]
+          self.no_content_type = true
+        end
+
         lookup_context.formats = [format.to_sym]
         lookup_context.rendered_format = lookup_context.formats.first
       end