2 files changed, 35 insertions, 1 deletions
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
index cc989d6625..e85823d8db 100644
--- a/actionpack/lib/action_dispatch/http/mime_type.rb
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -10,7 +10,12 @@ module Mime
     %w(<< concat shift unshift push pop []= clear compact! collect!
     delete delete_at delete_if flatten! map! insert reject! reverse!
     replace slice! sort! uniq!).each do |method|
-      define_method(method) {|*args| @symbols = nil; super(*args) }
+      module_eval <<-CODE
+        def #{method}(*args)
+          @symbols = nil
+          super
+        end
+      CODE
     end
   end
 
diff --git a/actionpack/lib/action_dispatch/middleware/string_coercion.rb b/actionpack/lib/action_dispatch/middleware/string_coercion.rb
new file mode 100644
index 0000000000..232e947835
--- /dev/null
+++ b/actionpack/lib/action_dispatch/middleware/string_coercion.rb
@@ -0,0 +1,29 @@
+module ActionDispatch
+  class StringCoercion
+    class UglyBody < ActiveSupport::BasicObject
+      def initialize(body)
+        @body = body
+      end
+
+      def each
+        @body.each do |part|
+          yield part.to_s
+        end
+      end
+
+      private
+        def method_missing(*args, &block)
+          @body.__send__(*args, &block)
+        end
+    end
+
+    def initialize(app)
+      @app = app
+    end
+
+    def call(env)
+      status, headers, body = @app.call(env)
+      [status, headers, UglyBody.new(body)]
+    end
+  end
+end