Django Cannot resolve keyword 'items' into field. Choices are: id, name

Question

I've run into an error while trying to use the tagging package in my app.

Cannot resolve keyword 'items' into field. Choices are: id, name

Which is coming from this line of code:

current_tags = list(self.filter(items__content_type__pk=ctype.pk,
                                    items__object_id=obj.pk))

Here is the full traceback:

Request Method: POST
Request URL: http://localhost:8000/admin/coltrane/entry/add/

Django Version: 1.7
Python Version: 2.7.6
Installed Applications:
('django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.sites',
 'django.contrib.flatpages',
 'search',
 'coltrane',
 'markdown')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware')


Traceback:
File "/Library/Python/2.7/site-packages/django/core/handlers/base.py" in get_response
  111.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in wrapper
  567.                 return self.admin_site.admin_view(view)(*args, **kwargs)
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  105.                     response = view_func(request, *args, **kwargs)
File "/Library/Python/2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  52.         response = view_func(request, *args, **kwargs)
File "/Library/Python/2.7/site-packages/django/contrib/admin/sites.py" in inner
  204.             return view(request, *args, **kwargs)
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in add_view
  1437.         return self.changeform_view(request, None, form_url, extra_context)
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in _wrapper
  29.             return bound_func(*args, **kwargs)
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  105.                     response = view_func(request, *args, **kwargs)
File "/Library/Python/2.7/site-packages/django/utils/decorators.py" in bound_func
  25.                 return func.__get__(self, type(self))(*args2, **kwargs2)
File "/Library/Python/2.7/site-packages/django/db/transaction.py" in inner
  394.                 return func(*args, **kwargs)
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in changeform_view
  1388.                 self.save_model(request, new_object, form, not add)
File "/Library/Python/2.7/site-packages/django/contrib/admin/options.py" in save_model
  1029.         obj.save()
File "/Library/Python/2.7/site-packages/django/db/models/base.py" in save
  590.                        force_update=force_update, update_fields=update_fields)
File "/Library/Python/2.7/site-packages/django/db/models/base.py" in save_base
  627.                                    update_fields=update_fields, raw=raw, using=using)
File "/Library/Python/2.7/site-packages/django/dispatch/dispatcher.py" in send
  198.             response = receiver(signal=self, sender=sender, **named)
File "/Users/byrd/Virtual_env_new/lib/python2.7/site-packages/tagging/fields.py" in _save
  81.             Tag.objects.update_tags(kwargs['instance'], tags)
File "/Users/byrd/Virtual_env_new/lib/python2.7/site-packages/tagging/models.py" in update_tags
  34.                                         items__object_id=obj.pk))
File "/Library/Python/2.7/site-packages/django/db/models/manager.py" in manager_method
  92.                 return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/Library/Python/2.7/site-packages/django/db/models/query.py" in filter
  691.         return self._filter_or_exclude(False, *args, **kwargs)
File "/Library/Python/2.7/site-packages/django/db/models/query.py" in _filter_or_exclude
  709.             clone.query.add_q(Q(*args, **kwargs))
File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in add_q
  1287.         clause, require_inner = self._add_q(where_part, self.used_aliases)
File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in _add_q
  1314.                     current_negated=current_negated, connector=connector)
File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in build_filter
  1138.         lookups, parts, reffed_aggregate = self.solve_lookup_type(arg)
File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in solve_lookup_type
  1076.         _, field, _, lookup_parts = self.names_to_path(lookup_splitted, self.get_meta())
File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in names_to_path
  1383.             self.raise_field_error(opts, name)
File "/Library/Python/2.7/site-packages/django/db/models/sql/query.py" in raise_field_error
  1389.                          "Choices are: %s" % (name, ", ".join(available)))

Exception Type: FieldError at /admin/coltrane/entry/add/
Exception Value: Cannot resolve keyword 'items' into field. Choices are: id, name

Here is the model for Tagging "items is the related_name"

@python_2_unicode_compatible
class Tag(models.Model):
    """
    A tag.
    """
    name = models.CharField(_('name'), max_length=50, unique=True, db_index=True)

    objects = TagManager()

    class Meta:
        ordering = ('name',)
        verbose_name = _('tag')
        verbose_name_plural = _('tags')

    def __str__(self):
        return self.name


@python_2_unicode_compatible
class TaggedItem(models.Model):
    """
    Holds the relationship between a tag and the item being tagged.
    """
    tag = models.ForeignKey(Tag, verbose_name=_('tag'), related_name='items')
    content_type = models.ForeignKey(ContentType, verbose_name=_('content type'))
    object_id = models.PositiveIntegerField(_('object id'), db_index=True)
    object = generic.GenericForeignKey('content_type', 'object_id')

    objects = TaggedItemManager()

    class Meta:
        # Enforce unique tag association per object
        unique_together = (('tag', 'content_type', 'object_id'),)
        verbose_name = _('tagged item')
        verbose_name_plural = _('tagged items')

    def __str__(self):
        return '%s [%s]' % (smart_text(self.object), smart_text(self.tag))

Answer 1

I encountered this problem before.

It was because I forgot including the 'tagging' app into the INSTALLED_APP tuple of 'settings.py' for my site besides installing the 'tagging' app on the machine.

Hope it helps

Answer 2

For a Tag() to get all TaggedItem() objects where a specific Tag() is a ForeignKey on the TaggedItem() objects, you would want to access it as:

tag = Tag.objects.get(pk=1)  # for example
tag.taggeditem_set() # returns all related taggeditems

Here is the related Django Docs:

https://docs.djangoproject.com/en/dev/ref/models/relations/