Remove method missing use in respond_to

actionpack/lib/action_controller/mime_responds.rb

@@ -143,12 +143,31 @@ def any(*args, &block)
           custom(@mime_type_priority.first, &block)
         end
       end
+      
+      def self.generate_method_for_mime(mime)
+        sym = mime.is_a?(Symbol) ? mime : mime.to_sym
+        const = sym.to_s.upcase
+        class_eval <<-RUBY
+          def #{sym}(&block)                          # def html(&block)
+            if Mime::SET.include?(Mime::#{const})     #   if Mime::Set.include?(Mime::HTML)
+              custom(Mime::#{const}, &block)          #     custom(Mime::HTML, &block)
+            else                                      #   else
+              super                                   #     super
+            end                                       #   end
+          end                                         # end
+        RUBY
+      end
 
-      def method_missing(symbol, &block)
-        mime_constant = symbol.to_s.upcase
+      Mime::SET.each do |mime|
+        generate_method_for_mime(mime)
+      end
 
-        if Mime::SET.include?(Mime.const_get(mime_constant))
-          custom(Mime.const_get(mime_constant), &block)
+      def method_missing(symbol, &block)
+        mime_constant = Mime.const_get(symbol.to_s.upcase)
+      
+        if Mime::SET.include?(mime_constant)
+          self.class.generate_method_for_mime(mime_constant)
+          send(symbol, &block)
         else
           super
         end