libs/session_messages/context_processors.py

   1 """
   2 Context processor for lightweight session messages.
   3
   4 Time-stamp: <2008-07-19 23:16:19 carljm context_processors.py>
   5
   6 """
   7 from django.utils.encoding import StrAndUnicode
   8
   9 from session_messages import get_and_delete_messages
  10
  11 def session_messages (request):
  12     """
  13     Returns session messages for the current session.
  14
  15     """
  16     return { 'session_messages': LazyMessages(request) }
  17
  18 class LazyMessages (StrAndUnicode):
  19     """
  20     Lazy message container, so messages aren't actually retrieved from
  21     session and deleted until the template asks for them.
  22
  23     """
  24     def __init__(self, request):
  25         self.request = request
  26
  27     def __iter__(self):
  28         return iter(self.messages)
  29
  30     def __len__(self):
  31         return len(self.messages)
  32
  33     def __nonzero__(self):
  34         return bool(self.messages)
  35
  36     def __unicode__(self):
  37         return unicode(self.messages)
  38
  39     def __getitem__(self, *args, **kwargs):
  40         return self.messages.__getitem__(*args, **kwargs)
  41
  42     def _get_messages(self):
  43         if hasattr(self, '_messages'):
  44             return self._messages
  45         self._messages = get_and_delete_messages(self.request)
  46         return self._messages
  47     messages = property(_get_messages)
  48