Django-1.2.1/build/lib.linux-i686-2.6/django/contrib/messages/middleware.py

   1 from django.conf import settings
   2 from django.contrib.messages.storage import default_storage
   3
   4
   5 class MessageMiddleware(object):
   6     """
   7     Middleware that handles temporary messages.
   8     """
   9
  10     def process_request(self, request):
  11         request._messages = default_storage(request)
  12
  13     def process_response(self, request, response):
  14         """
  15         Updates the storage backend (i.e., saves the messages).
  16
  17         If not all messages could not be stored and ``DEBUG`` is ``True``, a
  18         ``ValueError`` is raised.
  19         """
  20         # A higher middleware layer may return a request which does not contain
  21         # messages storage, so make no assumption that it will be there.
  22         if hasattr(request, '_messages'):
  23             unstored_messages = request._messages.update(response)
  24             if unstored_messages and settings.DEBUG:
  25                 raise ValueError('Not all temporary messages could be stored.')
  26         return response