philo/templatetags/containers.py

   1 """
   2 The container template tags are automatically included as builtins if :mod:`philo` is an installed app.
   3
   4 .. templatetag:: container
   5
   6 container
   7 ---------
   8
   9 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.
  10
  11 Usage::
  12
  13         {% container <name> [[references <app_label>.<model_name>] as <variable>] %}
  14
  15 """
  16
  17 from django import template
  18 from django.conf import settings
  19 from django.contrib.contenttypes.models import ContentType
  20 from django.core.exceptions import ObjectDoesNotExist
  21 from django.utils.safestring import SafeUnicode, mark_safe
  22
  23
  24 register = template.Library()
  25
  26
  27 class ContainerNode(template.Node):
  28         def __init__(self, name, references=None, as_var=None):
  29                 self.name = name
  30                 self.as_var = as_var
  31                 self.references = references
  32
  33         def render(self, context):
  34                 content = settings.TEMPLATE_STRING_IF_INVALID
  35                 if 'page' in context:
  36                         container_content = self.get_container_content(context)
  37                 else:
  38                         container_content = None
  39
  40                 if self.as_var:
  41                         context[self.as_var] = container_content
  42                         return ''
  43
  44                 if not container_content:
  45                         return ''
  46
  47                 return container_content
  48
  49         def get_container_content(self, context):
  50                 page = context['page']
  51                 if self.references:
  52                         # Then it's a content reference.
  53                         try:
  54                                 contentreference = page.contentreferences.get(name__exact=self.name, content_type=self.references)
  55                                 content = contentreference.content
  56                         except ObjectDoesNotExist:
  57                                 content = ''
  58                 else:
  59                         # Otherwise it's a contentlet.
  60                         try:
  61                                 contentlet = page.contentlets.get(name__exact=self.name)
  62                                 if '{%' in contentlet.content or '{{' in contentlet.content:
  63                                         try:
  64                                                 content = template.Template(contentlet.content, name=contentlet.name).render(context)
  65                                         except template.TemplateSyntaxError, error:
  66                                                 if settings.DEBUG:
  67                                                         content = ('[Error parsing contentlet \'%s\': %s]' % (self.name, error))
  68                                                 else:
  69                                                         content = settings.TEMPLATE_STRING_IF_INVALID
  70                                 else:
  71                                         content = contentlet.content
  72                         except ObjectDoesNotExist:
  73                                 content = settings.TEMPLATE_STRING_IF_INVALID
  74                         content = mark_safe(content)
  75                 return content
  76
  77
  78 def do_container(parser, token):
  79         """
  80         {% container <name> [[references <app_label>.<model_name>] as <variable>] %}
  81
  82         """
  83         params = token.split_contents()
  84         if len(params) >= 2:
  85                 tag = params[0]
  86                 name = params[1].strip('"')
  87                 references = None
  88                 as_var = None
  89                 if len(params) > 2:
  90                         remaining_tokens = params[2:]
  91                         while remaining_tokens:
  92                                 option_token = remaining_tokens.pop(0)
  93                                 if option_token == 'references':
  94                                         try:
  95                                                 app_label, model = remaining_tokens.pop(0).strip('"').split('.')
  96                                                 references = ContentType.objects.get(app_label=app_label, model=model)
  97                                         except IndexError:
  98                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument specifying a content type' % tag)
  99                                         except ValueError:
 100                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument of the form app_label.model (see django.contrib.contenttypes)' % tag)
 101                                         except ObjectDoesNotExist:
 102                                                 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)
 103                                 elif option_token == 'as':
 104                                         try:
 105                                                 as_var = remaining_tokens.pop(0)
 106                                         except IndexError:
 107                                                 raise template.TemplateSyntaxError('"%s" template tag option "as" requires an argument specifying a variable name' % tag)
 108                         if references and not as_var:
 109                                 raise template.TemplateSyntaxError('"%s" template tags using "references" option require additional use of the "as" option specifying a variable name' % tag)
 110                 return ContainerNode(name, references, as_var)
 111
 112         else: # error
 113                 raise template.TemplateSyntaxError('"%s" template tag provided without arguments (at least one required)' % tag)
 114
 115
 116 register.tag('container', do_container)