app/django/contrib/comments/templatetags/comments.py
changeset 323 ff1a9aa48cfd
parent 54 03e267d67478
equal deleted inserted replaced
322:6641e941ef1e 323:ff1a9aa48cfd
     1 from django.contrib.comments.models import Comment, FreeComment
       
     2 from django.contrib.comments.models import PHOTOS_REQUIRED, PHOTOS_OPTIONAL, RATINGS_REQUIRED, RATINGS_OPTIONAL, IS_PUBLIC
       
     3 from django.contrib.comments.models import MIN_PHOTO_DIMENSION, MAX_PHOTO_DIMENSION
       
     4 from django import template
     1 from django import template
     5 from django.template import loader
     2 from django.template.loader import render_to_string
     6 from django.core.exceptions import ObjectDoesNotExist
     3 from django.conf import settings
     7 from django.contrib.contenttypes.models import ContentType
     4 from django.contrib.contenttypes.models import ContentType
     8 from django.utils.encoding import smart_str
     5 from django.contrib import comments
     9 import re
     6 from django.utils.encoding import smart_unicode
    10 
     7 
    11 register = template.Library()
     8 register = template.Library()
    12 
     9 
    13 COMMENT_FORM = 'comments/form.html'
    10 class BaseCommentNode(template.Node):
    14 FREE_COMMENT_FORM = 'comments/freeform.html'
    11     """
    15 
    12     Base helper class (abstract) for handling the get_comment_* template tags.
    16 class CommentFormNode(template.Node):
    13     Looks a bit strange, but the subclasses below should make this a bit more
    17     def __init__(self, content_type, obj_id_lookup_var, obj_id, free,
    14     obvious.
    18         photos_optional=False, photos_required=False, photo_options='',
    15     """
    19         ratings_optional=False, ratings_required=False, rating_options='',
    16 
    20         is_public=True):
    17     #@classmethod
    21         self.content_type = content_type
    18     def handle_token(cls, parser, token):
    22         if obj_id_lookup_var is not None:
    19         """Class method to parse get_comment_list/count/form and return a Node."""
    23             obj_id_lookup_var = template.Variable(obj_id_lookup_var)
    20         tokens = token.contents.split()
    24         self.obj_id_lookup_var, self.obj_id, self.free = obj_id_lookup_var, obj_id, free
    21         if tokens[1] != 'for':
    25         self.photos_optional, self.photos_required = photos_optional, photos_required
    22             raise template.TemplateSyntaxError("Second argument in %r tag must be 'for'" % tokens[0])
    26         self.ratings_optional, self.ratings_required = ratings_optional, ratings_required
    23 
    27         self.photo_options, self.rating_options = photo_options, rating_options
    24         # {% get_whatever for obj as varname %}
    28         self.is_public = is_public
    25         if len(tokens) == 5:
       
    26             if tokens[3] != 'as':
       
    27                 raise template.TemplateSyntaxError("Third argument in %r must be 'as'" % tokens[0])
       
    28             return cls(
       
    29                 object_expr = parser.compile_filter(tokens[2]),
       
    30                 as_varname = tokens[4],
       
    31             )
       
    32 
       
    33         # {% get_whatever for app.model pk as varname %}
       
    34         elif len(tokens) == 6:
       
    35             if tokens[4] != 'as':
       
    36                 raise template.TemplateSyntaxError("Fourth argument in %r must be 'as'" % tokens[0])
       
    37             return cls(
       
    38                 ctype = BaseCommentNode.lookup_content_type(tokens[2], tokens[0]),
       
    39                 object_pk_expr = parser.compile_filter(tokens[3]),
       
    40                 as_varname = tokens[5]
       
    41             )
       
    42 
       
    43         else:
       
    44             raise template.TemplateSyntaxError("%r tag requires 4 or 5 arguments" % tokens[0])
       
    45 
       
    46     handle_token = classmethod(handle_token)
       
    47 
       
    48     #@staticmethod
       
    49     def lookup_content_type(token, tagname):
       
    50         try:
       
    51             app, model = token.split('.')
       
    52             return ContentType.objects.get(app_label=app, model=model)
       
    53         except ValueError:
       
    54             raise template.TemplateSyntaxError("Third argument in %r must be in the format 'app.model'" % tagname)
       
    55         except ContentType.DoesNotExist:
       
    56             raise template.TemplateSyntaxError("%r tag has non-existant content-type: '%s.%s'" % (tagname, app, model))
       
    57     lookup_content_type = staticmethod(lookup_content_type)
       
    58 
       
    59     def __init__(self, ctype=None, object_pk_expr=None, object_expr=None, as_varname=None, comment=None):
       
    60         if ctype is None and object_expr is None:
       
    61             raise template.TemplateSyntaxError("Comment nodes must be given either a literal object or a ctype and object pk.")
       
    62         self.comment_model = comments.get_model()
       
    63         self.as_varname = as_varname
       
    64         self.ctype = ctype
       
    65         self.object_pk_expr = object_pk_expr
       
    66         self.object_expr = object_expr
       
    67         self.comment = comment
    29 
    68 
    30     def render(self, context):
    69     def render(self, context):
    31         from django.conf import settings
    70         qs = self.get_query_set(context)
    32         from django.utils.text import normalize_newlines
    71         context[self.as_varname] = self.get_context_value_from_queryset(context, qs)
    33         import base64
    72         return ''
    34         context.push()
    73 
    35         if self.obj_id_lookup_var is not None:
    74     def get_query_set(self, context):
       
    75         ctype, object_pk = self.get_target_ctype_pk(context)
       
    76         if not object_pk:
       
    77             return self.comment_model.objects.none()
       
    78 
       
    79         qs = self.comment_model.objects.filter(
       
    80             content_type = ctype,
       
    81             object_pk    = smart_unicode(object_pk),
       
    82             site__pk     = settings.SITE_ID,
       
    83             is_public    = True,
       
    84         )
       
    85         if getattr(settings, 'COMMENTS_HIDE_REMOVED', True):
       
    86             qs = qs.filter(is_removed=False)
       
    87 
       
    88         return qs
       
    89 
       
    90     def get_target_ctype_pk(self, context):
       
    91         if self.object_expr:
    36             try:
    92             try:
    37                 self.obj_id = self.obj_id_lookup_var.resolve(context)
    93                 obj = self.object_expr.resolve(context)
    38             except template.VariableDoesNotExist:
    94             except template.VariableDoesNotExist:
    39                 return ''
    95                 return None, None
    40             # Validate that this object ID is valid for this content-type.
    96             return ContentType.objects.get_for_model(obj), obj.pk
    41             # We only have to do this validation if obj_id_lookup_var is provided,
    97         else:
    42             # because do_comment_form() validates hard-coded object IDs.
    98             return self.ctype, self.object_pk_expr.resolve(context, ignore_failures=True)
    43             try:
    99 
    44                 self.content_type.get_object_for_this_type(pk=self.obj_id)
   100     def get_context_value_from_queryset(self, context, qs):
    45             except ObjectDoesNotExist:
   101         """Subclasses should override this."""
    46                 context['display_form'] = False
   102         raise NotImplementedError
    47             else:
   103 
    48                 context['display_form'] = True
   104 class CommentListNode(BaseCommentNode):
    49         else:
   105     """Insert a list of comments into the context."""
    50             context['display_form'] = True
   106     def get_context_value_from_queryset(self, context, qs):
    51         context['target'] = '%s:%s' % (self.content_type.id, self.obj_id)
   107         return list(qs)
    52         options = []
   108 
    53         for var, abbr in (('photos_required', PHOTOS_REQUIRED),
   109 class CommentCountNode(BaseCommentNode):
    54                           ('photos_optional', PHOTOS_OPTIONAL),
   110     """Insert a count of comments into the context."""
    55                           ('ratings_required', RATINGS_REQUIRED),
   111     def get_context_value_from_queryset(self, context, qs):
    56                           ('ratings_optional', RATINGS_OPTIONAL),
   112         return qs.count()
    57                           ('is_public', IS_PUBLIC)):
   113 
    58             context[var] = getattr(self, var)
   114 class CommentFormNode(BaseCommentNode):
    59             if getattr(self, var):
   115     """Insert a form for the comment model into the context."""
    60                 options.append(abbr)
   116 
    61         context['options'] = ','.join(options)
   117     def get_form(self, context):
    62         if self.free:
   118         ctype, object_pk = self.get_target_ctype_pk(context)
    63             context['hash'] = Comment.objects.get_security_hash(context['options'], '', '', context['target'])
   119         if object_pk:
    64             default_form = loader.get_template(FREE_COMMENT_FORM)
   120             return comments.get_form()(ctype.get_object_for_this_type(pk=object_pk))
    65         else:
   121         else:
    66             context['photo_options'] = self.photo_options
   122             return None
    67             context['rating_options'] = normalize_newlines(base64.encodestring(self.rating_options).strip())
       
    68             if self.rating_options:
       
    69                 context['rating_range'], context['rating_choices'] = Comment.objects.get_rating_options(self.rating_options)
       
    70             context['hash'] = Comment.objects.get_security_hash(context['options'], context['photo_options'], context['rating_options'], context['target'])
       
    71             context['logout_url'] = settings.LOGOUT_URL
       
    72             default_form = loader.get_template(COMMENT_FORM)
       
    73         output = default_form.render(context)
       
    74         context.pop()
       
    75         return output
       
    76 
       
    77 class CommentCountNode(template.Node):
       
    78     def __init__(self, package, module, context_var_name, obj_id, var_name, free):
       
    79         self.package, self.module = package, module
       
    80         if context_var_name is not None:
       
    81             context_var_name = template.Variable(context_var_name)
       
    82         self.context_var_name, self.obj_id = context_var_name, obj_id
       
    83         self.var_name, self.free = var_name, free
       
    84 
   123 
    85     def render(self, context):
   124     def render(self, context):
    86         from django.conf import settings
   125         context[self.as_varname] = self.get_form(context)
    87         manager = self.free and FreeComment.objects or Comment.objects
       
    88         if self.context_var_name is not None:
       
    89             self.obj_id = self.context_var_name.resolve(context)
       
    90         comment_count = manager.filter(object_id__exact=self.obj_id,
       
    91             content_type__app_label__exact=self.package,
       
    92             content_type__model__exact=self.module, site__id__exact=settings.SITE_ID).count()
       
    93         context[self.var_name] = comment_count
       
    94         return ''
   126         return ''
    95 
   127 
    96 class CommentListNode(template.Node):
   128 class RenderCommentFormNode(CommentFormNode):
    97     def __init__(self, package, module, context_var_name, obj_id, var_name, free, ordering, extra_kwargs=None):
   129     """Render the comment form directly"""
    98         self.package, self.module = package, module
   130 
    99         if context_var_name is not None:
   131     #@classmethod
   100             context_var_name = template.Variable(context_var_name)
   132     def handle_token(cls, parser, token):
   101         self.context_var_name, self.obj_id = context_var_name, obj_id
   133         """Class method to parse render_comment_form and return a Node."""
   102         self.var_name, self.free = var_name, free
   134         tokens = token.contents.split()
   103         self.ordering = ordering
   135         if tokens[1] != 'for':
   104         self.extra_kwargs = extra_kwargs or {}
   136             raise template.TemplateSyntaxError("Second argument in %r tag must be 'for'" % tokens[0])
       
   137 
       
   138         # {% render_comment_form for obj %}
       
   139         if len(tokens) == 3:
       
   140             return cls(object_expr=parser.compile_filter(tokens[2]))
       
   141 
       
   142         # {% render_comment_form for app.models pk %}
       
   143         elif len(tokens) == 4:
       
   144             return cls(
       
   145                 ctype = BaseCommentNode.lookup_content_type(tokens[2], tokens[0]),
       
   146                 object_pk_expr = parser.compile_filter(tokens[3])
       
   147             )
       
   148     handle_token = classmethod(handle_token)
   105 
   149 
   106     def render(self, context):
   150     def render(self, context):
   107         from django.conf import settings
   151         ctype, object_pk = self.get_target_ctype_pk(context)
   108         get_list_function = self.free and FreeComment.objects.filter or Comment.objects.get_list_with_karma
   152         if object_pk:
   109         if self.context_var_name is not None:
   153             template_search_list = [
   110             try:
   154                 "comments/%s/%s/form.html" % (ctype.app_label, ctype.model),
   111                 self.obj_id = self.context_var_name.resolve(context)
   155                 "comments/%s/form.html" % ctype.app_label,
   112             except template.VariableDoesNotExist:
   156                 "comments/form.html"
   113                 return ''
   157             ]
   114         kwargs = {
   158             context.push()
   115             'object_id__exact': self.obj_id,
   159             formstr = render_to_string(template_search_list, {"form" : self.get_form(context)}, context)
   116             'content_type__app_label__exact': self.package,
   160             context.pop()
   117             'content_type__model__exact': self.module,
   161             return formstr
   118             'site__id__exact': settings.SITE_ID,
   162         else:
   119         }
   163             return ''
   120         kwargs.update(self.extra_kwargs)
   164 
   121         comment_list = get_list_function(**kwargs).order_by(self.ordering + 'submit_date').select_related()
   165 # We could just register each classmethod directly, but then we'd lose out on
   122         if not self.free and settings.COMMENTS_BANNED_USERS_GROUP:
   166 # the automagic docstrings-into-admin-docs tricks. So each node gets a cute
   123             comment_list = comment_list.extra(select={'is_hidden': 'user_id IN (SELECT user_id FROM auth_user_groups WHERE group_id = %s)' % settings.COMMENTS_BANNED_USERS_GROUP})
   167 # wrapper function that just exists to hold the docstring.
   124 
   168 
   125         if not self.free:
   169 #@register.tag
   126             if 'user' in context and context['user'].is_authenticated():
   170 def get_comment_count(parser, token):
   127                 user_id = context['user'].id
   171     """
   128                 context['user_can_moderate_comments'] = Comment.objects.user_is_moderator(context['user'])
   172     Gets the comment count for the given params and populates the template
   129             else:
   173     context with a variable containing that value, whose name is defined by the
   130                 user_id = None
   174     'as' clause.
   131                 context['user_can_moderate_comments'] = False
   175 
   132             # Only display comments by banned users to those users themselves.
   176     Syntax::
   133             if settings.COMMENTS_BANNED_USERS_GROUP:
   177 
   134                 comment_list = [c for c in comment_list if not c.is_hidden or (user_id == c.user_id)]
   178         {% get_comment_count for [object] as [varname]  %}
   135 
   179         {% get_comment_count for [app].[model] [object_id] as [varname]  %}
   136         context[self.var_name] = comment_list
       
   137         return ''
       
   138 
       
   139 class DoCommentForm:
       
   140     """
       
   141     Displays a comment form for the given params.
       
   142 
       
   143     Syntax::
       
   144 
       
   145         {% comment_form for [pkg].[py_module_name] [context_var_containing_obj_id] with [list of options] %}
       
   146 
   180 
   147     Example usage::
   181     Example usage::
   148 
   182 
   149         {% comment_form for lcom.eventtimes event.id with is_public yes photos_optional thumbs,200,400 ratings_optional scale:1-5|first_option|second_option %}
   183         {% get_comment_count for event as comment_count %}
   150 
   184         {% get_comment_count for calendar.event event.id as comment_count %}
   151     ``[context_var_containing_obj_id]`` can be a hard-coded integer or a variable containing the ID.
   185         {% get_comment_count for calendar.event 17 as comment_count %}
   152     """
   186 
   153     def __init__(self, free):
   187     """
   154         self.free = free
   188     return CommentCountNode.handle_token(parser, token)
   155 
   189 
   156     def __call__(self, parser, token):
   190 #@register.tag
   157         tokens = token.contents.split()
   191 def get_comment_list(parser, token):
   158         if len(tokens) < 4:
   192     """
   159             raise template.TemplateSyntaxError, "%r tag requires at least 3 arguments" % tokens[0]
   193     Gets the list of comments for the given params and populates the template
   160         if tokens[1] != 'for':
   194     context with a variable containing that value, whose name is defined by the
   161             raise template.TemplateSyntaxError, "Second argument in %r tag must be 'for'" % tokens[0]
   195     'as' clause.
   162         try:
   196 
   163             package, module = tokens[2].split('.')
   197     Syntax::
   164         except ValueError: # unpack list of wrong size
   198 
   165             raise template.TemplateSyntaxError, "Third argument in %r tag must be in the format 'package.module'" % tokens[0]
   199         {% get_comment_list for [object] as [varname]  %}
   166         try:
   200         {% get_comment_list for [app].[model] [object_id] as [varname]  %}
   167             content_type = ContentType.objects.get(app_label__exact=package, model__exact=module)
       
   168         except ContentType.DoesNotExist:
       
   169             raise template.TemplateSyntaxError, "%r tag has invalid content-type '%s.%s'" % (tokens[0], package, module)
       
   170         obj_id_lookup_var, obj_id = None, None
       
   171         if tokens[3].isdigit():
       
   172             obj_id = tokens[3]
       
   173             try: # ensure the object ID is valid
       
   174                 content_type.get_object_for_this_type(pk=obj_id)
       
   175             except ObjectDoesNotExist:
       
   176                 raise template.TemplateSyntaxError, "%r tag refers to %s object with ID %s, which doesn't exist" % (tokens[0], content_type.name, obj_id)
       
   177         else:
       
   178             obj_id_lookup_var = tokens[3]
       
   179         kwargs = {}
       
   180         if len(tokens) > 4:
       
   181             if tokens[4] != 'with':
       
   182                 raise template.TemplateSyntaxError, "Fourth argument in %r tag must be 'with'" % tokens[0]
       
   183             for option, args in zip(tokens[5::2], tokens[6::2]):
       
   184                 option = smart_str(option)
       
   185                 if option in ('photos_optional', 'photos_required') and not self.free:
       
   186                     # VALIDATION ##############################################
       
   187                     option_list = args.split(',')
       
   188                     if len(option_list) % 3 != 0:
       
   189                         raise template.TemplateSyntaxError, "Incorrect number of comma-separated arguments to %r tag" % tokens[0]
       
   190                     for opt in option_list[::3]:
       
   191                         if not opt.isalnum():
       
   192                             raise template.TemplateSyntaxError, "Invalid photo directory name in %r tag: '%s'" % (tokens[0], opt)
       
   193                     for opt in option_list[1::3] + option_list[2::3]:
       
   194                         if not opt.isdigit() or not (MIN_PHOTO_DIMENSION <= int(opt) <= MAX_PHOTO_DIMENSION):
       
   195                             raise template.TemplateSyntaxError, "Invalid photo dimension in %r tag: '%s'. Only values between %s and %s are allowed." % (tokens[0], opt, MIN_PHOTO_DIMENSION, MAX_PHOTO_DIMENSION)
       
   196                     # VALIDATION ENDS #########################################
       
   197                     kwargs[option] = True
       
   198                     kwargs['photo_options'] = args
       
   199                 elif option in ('ratings_optional', 'ratings_required') and not self.free:
       
   200                     # VALIDATION ##############################################
       
   201                     if 2 < len(args.split('|')) > 9:
       
   202                         raise template.TemplateSyntaxError, "Incorrect number of '%s' options in %r tag. Use between 2 and 8." % (option, tokens[0])
       
   203                     if re.match('^scale:\d+\-\d+\:$', args.split('|')[0]):
       
   204                         raise template.TemplateSyntaxError, "Invalid 'scale' in %r tag's '%s' options" % (tokens[0], option)
       
   205                     # VALIDATION ENDS #########################################
       
   206                     kwargs[option] = True
       
   207                     kwargs['rating_options'] = args
       
   208                 elif option in ('is_public'):
       
   209                     kwargs[option] = (args == 'true')
       
   210                 else:
       
   211                     raise template.TemplateSyntaxError, "%r tag got invalid parameter '%s'" % (tokens[0], option)
       
   212         return CommentFormNode(content_type, obj_id_lookup_var, obj_id, self.free, **kwargs)
       
   213 
       
   214 class DoCommentCount:
       
   215     """
       
   216     Gets comment count for the given params and populates the template context
       
   217     with a variable containing that value, whose name is defined by the 'as'
       
   218     clause.
       
   219 
       
   220     Syntax::
       
   221 
       
   222         {% get_comment_count for [pkg].[py_module_name] [context_var_containing_obj_id] as [varname]  %}
       
   223 
   201 
   224     Example usage::
   202     Example usage::
   225 
   203 
   226         {% get_comment_count for lcom.eventtimes event.id as comment_count %}
   204         {% get_comment_list for event as comment_list %}
   227 
   205         {% for comment in comment_list %}
   228     Note: ``[context_var_containing_obj_id]`` can also be a hard-coded integer, like this::
   206             ...
   229 
   207         {% endfor %}
   230         {% get_comment_count for lcom.eventtimes 23 as comment_count %}
   208 
   231     """
   209     """
   232     def __init__(self, free):
   210     return CommentListNode.handle_token(parser, token)
   233         self.free = free
   211 
   234 
   212 #@register.tag
   235     def __call__(self, parser, token):
   213 def get_comment_form(parser, token):
   236         tokens = token.contents.split()
   214     """
   237         # Now tokens is a list like this:
   215     Get a (new) form object to post a new comment.
   238         # ['get_comment_list', 'for', 'lcom.eventtimes', 'event.id', 'as', 'comment_list']
   216 
   239         if len(tokens) != 6:
   217     Syntax::
   240             raise template.TemplateSyntaxError, "%r tag requires 5 arguments" % tokens[0]
   218 
   241         if tokens[1] != 'for':
   219         {% get_comment_form for [object] as [varname] %}
   242             raise template.TemplateSyntaxError, "Second argument in %r tag must be 'for'" % tokens[0]
   220         {% get_comment_form for [app].[model] [object_id] as [varname] %}
   243         try:
   221     """
   244             package, module = tokens[2].split('.')
   222     return CommentFormNode.handle_token(parser, token)
   245         except ValueError: # unpack list of wrong size
   223 
   246             raise template.TemplateSyntaxError, "Third argument in %r tag must be in the format 'package.module'" % tokens[0]
   224 #@register.tag
   247         try:
   225 def render_comment_form(parser, token):
   248             content_type = ContentType.objects.get(app_label__exact=package, model__exact=module)
   226     """
   249         except ContentType.DoesNotExist:
   227     Render the comment form (as returned by ``{% render_comment_form %}``) through
   250             raise template.TemplateSyntaxError, "%r tag has invalid content-type '%s.%s'" % (tokens[0], package, module)
   228     the ``comments/form.html`` template.
   251         var_name, obj_id = None, None
   229 
   252         if tokens[3].isdigit():
   230     Syntax::
   253             obj_id = tokens[3]
   231 
   254             try: # ensure the object ID is valid
   232         {% render_comment_form for [object] %}
   255                 content_type.get_object_for_this_type(pk=obj_id)
   233         {% render_comment_form for [app].[model] [object_id] %}
   256             except ObjectDoesNotExist:
   234     """
   257                 raise template.TemplateSyntaxError, "%r tag refers to %s object with ID %s, which doesn't exist" % (tokens[0], content_type.name, obj_id)
   235     return RenderCommentFormNode.handle_token(parser, token)
   258         else:
   236 
   259             var_name = tokens[3]
   237 #@register.simple_tag
   260         if tokens[4] != 'as':
   238 def comment_form_target():
   261             raise template.TemplateSyntaxError, "Fourth argument in %r must be 'as'" % tokens[0]
   239     """
   262         return CommentCountNode(package, module, var_name, obj_id, tokens[5], self.free)
   240     Get the target URL for the comment form.
   263 
   241 
   264 class DoGetCommentList:
   242     Example::
   265     """
   243 
   266     Gets comments for the given params and populates the template context with a
   244         <form action="{% comment_form_target %}" method="POST">
   267     special comment_package variable, whose name is defined by the ``as``
   245     """
   268     clause.
   246     return comments.get_form_target()
   269 
   247 
   270     Syntax::
   248 register.tag(get_comment_count)
   271 
   249 register.tag(get_comment_list)
   272         {% get_comment_list for [pkg].[py_module_name] [context_var_containing_obj_id] as [varname] (reversed) %}
   250 register.tag(get_comment_form)
   273 
   251 register.tag(render_comment_form)
   274     Example usage::
   252 register.simple_tag(comment_form_target)
   275 
       
   276         {% get_comment_list for lcom.eventtimes event.id as comment_list %}
       
   277 
       
   278     Note: ``[context_var_containing_obj_id]`` can also be a hard-coded integer, like this::
       
   279 
       
   280         {% get_comment_list for lcom.eventtimes 23 as comment_list %}
       
   281 
       
   282     To get a list of comments in reverse order -- that is, most recent first --
       
   283     pass ``reversed`` as the last param::
       
   284 
       
   285         {% get_comment_list for lcom.eventtimes event.id as comment_list reversed %}
       
   286     """
       
   287     def __init__(self, free):
       
   288         self.free = free
       
   289 
       
   290     def __call__(self, parser, token):
       
   291         tokens = token.contents.split()
       
   292         # Now tokens is a list like this:
       
   293         # ['get_comment_list', 'for', 'lcom.eventtimes', 'event.id', 'as', 'comment_list']
       
   294         if not len(tokens) in (6, 7):
       
   295             raise template.TemplateSyntaxError, "%r tag requires 5 or 6 arguments" % tokens[0]
       
   296         if tokens[1] != 'for':
       
   297             raise template.TemplateSyntaxError, "Second argument in %r tag must be 'for'" % tokens[0]
       
   298         try:
       
   299             package, module = tokens[2].split('.')
       
   300         except ValueError: # unpack list of wrong size
       
   301             raise template.TemplateSyntaxError, "Third argument in %r tag must be in the format 'package.module'" % tokens[0]
       
   302         try:
       
   303             content_type = ContentType.objects.get(app_label__exact=package,model__exact=module)
       
   304         except ContentType.DoesNotExist:
       
   305             raise template.TemplateSyntaxError, "%r tag has invalid content-type '%s.%s'" % (tokens[0], package, module)
       
   306         var_name, obj_id = None, None
       
   307         if tokens[3].isdigit():
       
   308             obj_id = tokens[3]
       
   309             try: # ensure the object ID is valid
       
   310                 content_type.get_object_for_this_type(pk=obj_id)
       
   311             except ObjectDoesNotExist:
       
   312                 raise template.TemplateSyntaxError, "%r tag refers to %s object with ID %s, which doesn't exist" % (tokens[0], content_type.name, obj_id)
       
   313         else:
       
   314             var_name = tokens[3]
       
   315         if tokens[4] != 'as':
       
   316             raise template.TemplateSyntaxError, "Fourth argument in %r must be 'as'" % tokens[0]
       
   317         if len(tokens) == 7:
       
   318             if tokens[6] != 'reversed':
       
   319                 raise template.TemplateSyntaxError, "Final argument in %r must be 'reversed' if given" % tokens[0]
       
   320             ordering = "-"
       
   321         else:
       
   322             ordering = ""
       
   323         return CommentListNode(package, module, var_name, obj_id, tokens[5], self.free, ordering)
       
   324 
       
   325 # registration comments
       
   326 register.tag('get_comment_list', DoGetCommentList(False))
       
   327 register.tag('comment_form', DoCommentForm(False))
       
   328 register.tag('get_comment_count', DoCommentCount(False))
       
   329 # free comments
       
   330 register.tag('get_free_comment_list', DoGetCommentList(True))
       
   331 register.tag('free_comment_form', DoCommentForm(True))
       
   332 register.tag('get_free_comment_count', DoCommentCount(True))