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                                 if '{%' in contentlet.content or '{{' in contentlet.content:
  52                                         try:
  53                                                 content = template.Template(contentlet.content, name=contentlet.name).render(context)
  54                                         except template.TemplateSyntaxError, error:
  55                                                 if settings.DEBUG:
  56                                                         content = ('[Error parsing contentlet \'%s\': %s]' % (self.name, error))
  57                                                 else:
  58                                                         content = settings.TEMPLATE_STRING_IF_INVALID
  59                                 else:
  60                                         content = contentlet.content
  61                         except ObjectDoesNotExist:
  62                                 content = settings.TEMPLATE_STRING_IF_INVALID
  63                         content = mark_safe(content)
  64                 return content
  65
  66
  67 @register.tag
  68 def container(parser, token):
  69         """
  70         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.
  71
  72         Usage::
  73
  74                 {% container <name> [[references <app_label>.<model_name>] as <variable>] %}
  75
  76         """
  77         params = token.split_contents()
  78         if len(params) >= 2:
  79                 tag = params[0]
  80                 name = params[1].strip('"')
  81                 references = None
  82                 as_var = None
  83                 if len(params) > 2:
  84                         remaining_tokens = params[2:]
  85                         while remaining_tokens:
  86                                 option_token = remaining_tokens.pop(0)
  87                                 if option_token == 'references':
  88                                         try:
  89                                                 app_label, model = remaining_tokens.pop(0).strip('"').split('.')
  90                                                 references = ContentType.objects.get_by_natural_key(app_label, model)
  91                                         except IndexError:
  92                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument specifying a content type' % tag)
  93                                         except ValueError:
  94                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument of the form app_label.model (see django.contrib.contenttypes)' % tag)
  95                                         except ObjectDoesNotExist:
  96                                                 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)
  97                                 elif option_token == 'as':
  98                                         try:
  99                                                 as_var = remaining_tokens.pop(0)
 100                                         except IndexError:
 101                                                 raise template.TemplateSyntaxError('"%s" template tag option "as" requires an argument specifying a variable name' % tag)
 102                         if references and not as_var:
 103                                 raise template.TemplateSyntaxError('"%s" template tags using "references" option require additional use of the "as" option specifying a variable name' % tag)
 104                 return ContainerNode(name, references, as_var)
 105
 106         else: # error
 107                 raise template.TemplateSyntaxError('"%s" template tag provided without arguments (at least one required)' % tag)