3 files changed, 19 insertions, 10 deletions
diff --git a/actionpack/lib/action_controller/metal/rack_delegation.rb b/actionpack/lib/action_controller/metal/rack_delegation.rb
index bdf6e88699..e1bee9e60c 100644
--- a/actionpack/lib/action_controller/metal/rack_delegation.rb
+++ b/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)
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
index ce37eaefd8..3c4ef596c7 100644
--- a/actionpack/lib/action_controller/metal/rendering.rb
+++ b/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
 
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 15a177aaff..f14ca1ea44 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/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)