Call the Django response middleware from Tornado views.

But discard any changes the Django response middleware may have made
to anything other than the content.

This allows us to, for example, output our nice database query logging
for get_updates requests.

(imported from commit e1d2fd38ceb4d73ff50bdfaad7c72ddb24d0fe16)

zephyr/management/commands/runtornado.py

@@ -9,6 +9,7 @@ import logging
 import time
 from tornado import ioloop
 from zephyr.lib.debug import interactive_debug_listen
+from zephyr.lib.response import json_response
 
 # A hack to keep track of how much time we spend working, versus sleeping in
 # the event loop.
@@ -229,6 +230,10 @@ class AsyncDjangoHandler(tornado.web.RequestHandler, base.BaseHandler):
                     urlresolvers.set_urlconf(urlconf)
                     resolver = urlresolvers.RegexURLResolver(r'^/', urlconf)
 
+                ### ADDED BY HUMBUG
+                request._resolver = resolver
+                ### END ADDED BY HUMBUG
+
                 callback, callback_args, callback_kwargs = resolver.resolve(
                         request.path_info)
 
@@ -314,6 +319,15 @@ class AsyncDjangoHandler(tornado.web.RequestHandler, base.BaseHandler):
             # Reset urlconf on the way out for isolation
             urlresolvers.set_urlconf(None)
 
+        ### HUMBUG CHANGE: The remainder of this function was moved
+        ### into its own function, just below, so we can call it from
+        ### finish().
+        response = self.apply_response_middleware(request, response, resolver)
+
+        return response
+
+    ### Copied from get_response (above in this file)
+    def apply_response_middleware(self, request, response, resolver):
         try:
             # Apply response middleware, regardless of the response
             for middleware_method in self._response_middleware:
@@ -343,4 +357,13 @@ class AsyncDjangoHandler(tornado.web.RequestHandler, base.BaseHandler):
         if response['result'] == 'error':
             self.set_status(400)
 
-        return superself.finish(response)
+        # Call the Django response middleware on our object so that
+        # e.g. our own logging code can run; but don't actually use
+        # the headers from that since sending those to Tornado seems
+        # tricky; instead just send the (already json-rendered)
+        # content on to Tornado
+        django_response = json_response(res_type=response['result'],
+                                        data=response, status=self.get_status())
+        django_response = self.apply_response_middleware(request, django_response,
+                                                         request._resolver)
+        return superself.finish(django_response.content)