philo/middleware.py

   1 from django.conf import settings
   2 from django.contrib.sites.models import Site
   3 from django.http import Http404
   4
   5 from philo.models import Node, View
   6
   7
   8 class LazyNode(object):
   9         def __get__(self, request, obj_type=None):
  10                 if not hasattr(request, '_cached_node_path'):
  11                         return None
  12
  13                 if not hasattr(request, '_found_node'):
  14                         try:
  15                                 current_site = Site.objects.get_current()
  16                         except Site.DoesNotExist:
  17                                 current_site = None
  18
  19                         path = request._cached_node_path
  20                         trailing_slash = False
  21                         if path[-1] == '/':
  22                                 trailing_slash = True
  23
  24                         try:
  25                                 node, subpath = Node.objects.get_with_path(path, root=getattr(current_site, 'root_node', None), absolute_result=False)
  26                         except Node.DoesNotExist:
  27                                 node = None
  28                         else:
  29                                 if subpath is None:
  30                                         subpath = ""
  31                                 subpath = "/" + subpath
  32
  33                                 if not node.handles_subpath(subpath):
  34                                         node = None
  35                                 else:
  36                                         if trailing_slash and subpath[-1] != "/":
  37                                                 subpath += "/"
  38
  39                                         node.subpath = subpath
  40
  41                         request._found_node = node
  42
  43                 return request._found_node
  44
  45
  46 class RequestNodeMiddleware(object):
  47         """Adds a ``node`` attribute, representing the currently-viewed node, to every incoming :class:`HttpRequest` object. This is required by :func:`philo.views.node_view`."""
  48         def process_request(self, request):
  49                 request.__class__.node = LazyNode()
  50
  51         def process_view(self, request, view_func, view_args, view_kwargs):
  52                 try:
  53                         request._cached_node_path = view_kwargs['path']
  54                 except KeyError:
  55                         pass
  56
  57         def process_exception(self, request, exception):
  58                 if settings.DEBUG or not hasattr(request, 'node') or not request.node:
  59                         return
  60
  61                 if isinstance(exception, Http404):
  62                         error_view = request.node.attributes.get('Http404', None)
  63                 else:
  64                         error_view = request.node.attributes.get('Http500', None)
  65
  66                 if error_view is None or not isinstance(error_view, View):
  67                         # Should this be duck-typing? Perhaps even no testing?
  68                         return
  69
  70                 extra_context = {'exception': exception}
  71                 return error_view.render_to_response(request, extra_context)