templatetags/collections.py

   1 from django import template
   2 from django.conf import settings
   3
   4
   5 register = template.Library()
   6
   7
   8 class MembersofNode(template.Node):
   9         def __init__(self, collection, model, as_var):
  10                 self.collection = template.Variable(collection)
  11                 self.model = template.Variable(model)
  12                 self.as_var = as_var
  13
  14         def render(self, context):
  15                 try:
  16                         collection = self.collection.resolve(context)
  17                         model = self.model.resolve(context)
  18                         context[self.as_var] = collection.members.with_model(model)
  19                 except:
  20                         pass
  21                 return settings.TEMPLATE_STRING_IF_INVALID
  22
  23
  24 def do_membersof(parser, token):
  25         """
  26         {% membersof <collection> with <model> as <var> %}
  27         """
  28         params=token.split_contents()
  29         tag = params[0]
  30
  31         if len(params) < 6:
  32                 raise template.TemplateSyntaxError('"%s" template tag requires six parameters' % tag)
  33
  34         if params[2] != 'with':
  35                 raise template.TemplateSyntaxError('"%s" template tag requires the third parameter to be "with"' % tag)
  36
  37         if params[4] != 'as':
  38                 raise template.TemplateSyntaxError('"%s" template tag requires the fifth parameter to be "as"' % tag)
  39
  40         return MembersofNode(collection=params[1], model=params[3], as_var=params[5])
  41
  42
  43 register.tag('membersof', do_membersof)