philo/templatetags/containers.py

   1 """
   2 The container template tags are automatically included as builtins if :mod:`philo` is an installed app.
   3
   4 """
   5
   6 from django import template
   7 from django.conf import settings
   8 from django.contrib.contenttypes.models import ContentType
   9 from django.core.exceptions import ObjectDoesNotExist
  10 from django.utils.safestring import SafeUnicode, mark_safe
  11
  12
  13 register = template.Library()
  14
  15
  16 class ContainerNode(template.Node):
  17         def __init__(self, name, references=None, as_var=None):
  18                 self.name = name
  19                 self.as_var = as_var
  20                 self.references = references
  21
  22         def render(self, context):
  23                 content = settings.TEMPLATE_STRING_IF_INVALID
  24                 if 'page' in context:
  25                         container_content = self.get_container_content(context)
  26                 else:
  27                         container_content = None
  28
  29                 if self.as_var:
  30                         context[self.as_var] = container_content
  31                         return ''
  32
  33                 if not container_content:
  34                         return ''
  35
  36                 return container_content
  37
  38         def get_container_content(self, context):
  39                 page = context['page']
  40                 if self.references:
  41                         # Then it's a content reference.
  42                         try:
  43                                 contentreference = page.contentreferences.get(name__exact=self.name, content_type=self.references)
  44                                 content = contentreference.content
  45                         except ObjectDoesNotExist:
  46                                 content = ''
  47                 else:
  48                         # Otherwise it's a contentlet.
  49                         try:
  50                                 contentlet = page.contentlets.get(name__exact=self.name)
  51                                 content = contentlet.content
  52                         except ObjectDoesNotExist:
  53                                 content = ''
  54                 return content
  55
  56
  57 @register.tag
  58 def container(parser, token):
  59         """
  60         If a template using this tag is used to render a :class:`.Page`, that :class:`.Page` will have associated content which can be set in the admin interface. If a content type is referenced, then a :class:`.ContentReference` object will be created; otherwise, a :class:`.Contentlet` object will be created.
  61
  62         Usage::
  63
  64                 {% container <name> [[references <app_label>.<model_name>] as <variable>] %}
  65
  66         """
  67         params = token.split_contents()
  68         if len(params) >= 2:
  69                 tag = params[0]
  70                 name = params[1].strip('"')
  71                 references = None
  72                 as_var = None
  73                 if len(params) > 2:
  74                         remaining_tokens = params[2:]
  75                         while remaining_tokens:
  76                                 option_token = remaining_tokens.pop(0)
  77                                 if option_token == 'references':
  78                                         try:
  79                                                 app_label, model = remaining_tokens.pop(0).strip('"').split('.')
  80                                                 references = ContentType.objects.get_by_natural_key(app_label, model)
  81                                         except IndexError:
  82                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument specifying a content type' % tag)
  83                                         except ValueError:
  84                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument of the form app_label.model (see django.contrib.contenttypes)' % tag)
  85                                         except ObjectDoesNotExist:
  86                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument of the form app_label.model which refers to an installed content type (see django.contrib.contenttypes)' % tag)
  87                                 elif option_token == 'as':
  88                                         try:
  89                                                 as_var = remaining_tokens.pop(0)
  90                                         except IndexError:
  91                                                 raise template.TemplateSyntaxError('"%s" template tag option "as" requires an argument specifying a variable name' % tag)
  92                         if references and not as_var:
  93                                 raise template.TemplateSyntaxError('"%s" template tags using "references" option require additional use of the "as" option specifying a variable name' % tag)
  94                 return ContainerNode(name, references, as_var)
  95
  96         else: # error
  97                 raise template.TemplateSyntaxError('"%s" template tag provided without arguments (at least one required)' % tag)