templatetags/containers.py

   1 from django import template
   2 from django.conf import settings
   3 from django.utils.safestring import SafeUnicode, mark_safe
   4 from django.core.exceptions import ObjectDoesNotExist
   5 from django.contrib.contenttypes.models import ContentType
   6
   7
   8 register = template.Library()
   9
  10
  11 class ContainerNode(template.Node):
  12         child_nodelists = ('nodelist_main', 'nodelist_empty',)
  13
  14         def __init__(self, name, references=None, as_var=None, nodelist_main=None, nodelist_empty=None):
  15                 self.name = name
  16                 self.as_var = as_var
  17                 self.references = references
  18
  19                 if nodelist_main is None:
  20                         self.nodelist_main = template.NodeList()
  21                 else:
  22                         self.nodelist_main = nodelist_main
  23
  24                 if nodelist_empty is None:
  25                         self.nodelist_empty = template.NodeList()
  26                 else:
  27                         self.nodelist_empty = nodelist_empty
  28
  29         def render(self, context):
  30                 content = settings.TEMPLATE_STRING_IF_INVALID
  31                 if 'page' in context:
  32                         container_content = self.get_container_content(context['page'])
  33
  34                 if self.nodelist_main is None:
  35                         self.nodelist_main
  36                         if container_content and self.as_var:
  37                                 context[self.as_var] = container_content
  38                                 return ''
  39                         return container_content
  40
  41                 if container_content:
  42                         if self.as_var is None:
  43                                 self.as_var = self.name
  44
  45                         #make a new context
  46                         context.push()
  47                         context[self.as_var] = container_content
  48                         nodelist = template.NodeList()
  49                         for node in self.nodelist_main:
  50                                 nodelist.append(node.render(context))
  51                         context.pop()
  52                         return nodelist.render(context)
  53
  54                 if self.nodelist_empty is not None:
  55                         return self.nodelist_empty.render(context)
  56
  57                 return ''
  58
  59         def get_container_content(self, page):
  60                 if self.references:
  61                         try:
  62                                 contentreference = page.contentreferences.get(name__exact=self.name, content_type=self.references)
  63                                 content = contentreference.content
  64                         except ObjectDoesNotExist:
  65                                 content = ''
  66                 else:
  67                         try:
  68                                 contentlet = page.contentlets.get(name__exact=self.name)
  69                                 if contentlet.dynamic:
  70                                         try:
  71                                                 content = mark_safe(template.Template(contentlet.content, name=contentlet.name).render(context))
  72                                         except template.TemplateSyntaxError, error:
  73                                                 if settings.DEBUG:
  74                                                         content = ('[Error parsing contentlet \'%s\': %s]' % self.name, error)
  75                                 else:
  76                                         content = contentlet.content
  77                         except ObjectDoesNotExist:
  78                                 content = ''
  79                 return content
  80
  81
  82 def do_container(parser, token):
  83         """
  84         {% container <name> [[references <type>] as <variable>] %}
  85         {% blockcontainer <name> [[references <type>] as <variable>] %} [ {% empty %} ] {% endblockcontainer %}
  86         """
  87         params = token.split_contents()
  88         if len(params) >= 2:
  89                 tag = params[0]
  90                 name = params[1].strip('"')
  91                 references = None
  92                 as_var = None
  93                 if len(params) > 2:
  94                         remaining_tokens = params[2:]
  95                         while remaining_tokens:
  96                                 option_token = remaining_tokens.pop(0)
  97                                 if option_token == 'references':
  98                                         try:
  99                                                 app_label, model = remaining_tokens.pop(0).strip('"').split('.')
 100                                                 references = ContentType.objects.get(app_label=app_label, model=model)
 101                                         except IndexError:
 102                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument specifying a content type' % tag)
 103                                         except ValueError:
 104                                                 raise template.TemplateSyntaxError('"%s" template tag option "references" requires an argument of the form app_label.model (see django.contrib.contenttypes)' % tag)
 105                                         except ObjectDoesNotExist:
 106                                                 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)
 107                                 elif option_token == 'as':
 108                                         try:
 109                                                 as_var = remaining_tokens.pop(0)
 110                                         except IndexError:
 111                                                 raise template.TemplateSyntaxError('"%s" template tag option "as" requires an argument specifying a variable name' % tag)
 112                         if references and not as_var:
 113                                 raise template.TemplateSyntaxError('"%s" template tags using "references" option require additional use of the "as" option specifying a variable name' % tag)
 114                 if tag == 'container':
 115                         return ContainerNode(name, references, as_var)
 116
 117                 nodelist_main = parser.parse(('empty','endblockcontainer',))
 118                 token = parser.next_token()
 119
 120                 if token.contents == 'empty':
 121                         nodelist_empty = parser.parse(('endblockcontainer',))
 122                         parser.delete_first_token()
 123                 else:
 124                         nodelist_empty = None
 125                 return ContainerNode(name, references, as_var, nodelist_main, nodelist_empty)
 126
 127         else: # error
 128                 raise template.TemplateSyntaxError('"%s" template tag provided without arguments (at least one required)' % tag)
 129
 130
 131 register.tag('container', do_container)
 132 register.tag('blockcontainer', do_container)