Passing ordering parameter to the TaggableManager

So far I am doing it like this:

class _SortedTaggableManager(_TaggableManager):
    def get_queryset(self, *args, **kwargs):
        qs = super(_SortedTaggableManager, self).get_queryset(*args, **kwargs)
        return qs.order_by("name")

Then later in the code I am defining the following:

tags = TaggableManager(manager=_SortedTaggableManager)

But I feel it would be much easier to simply write:

tags = TaggableManager(ordering=["name"])

What do you think?

[kavdev]

Just throwing this out there for anyone who comes across this looking to solve prefetch_related query issues.

The taggable manager has a workaround in the get_queryset that helps avoid spawning a ton of queries. Removing that causes a specified prefetch_related to both send the prefetch query and then still fetch tags on each instance.

Here’s a version of @Natim’s manager that supports prefetch_related. I’ve submitted a version of this as a PR.

class _SortedTaggableManager(_TaggableManager):
    ordering = ["name"]

    def get_queryset(self, extra_filters=None):
        try:
            return self.instance._prefetched_objects_cache[self.prefetch_cache_name]
        except (AttributeError, KeyError):
            kwargs = extra_filters if extra_filters else {}
            return self.through.tags_for(self.model, self.instance, **kwargs).order_by(*self.ordering)

[nicorellius]

@rtpg Thanks for the reply. Apologies for the delay in getting back with you. To be fair, I implemented this a while back so the code is not fresh, but this is what I’ve got (I could totally be doing this wrong):

class TagColor(models.TextChoices):
    RED = 'RD', _('danger')
    BLUE = 'BU', _('primary')
    GREEN = 'GN', _('success')
    YELLOW = 'JR', _('warning')

class RNTag(TagBase):
    color = models.CharField(max_length=2, choices=TagColor.choices)

    class Meta:
        verbose_name = _('Tag')
        verbose_name_plural = _('Tags')
        ordering = ['color']

class RNsTaggedItem(GenericTaggedItemBase):
    tag = models.ForeignKey(
        RNTag,
        on_delete=models.CASCADE,
        related_name="%(app_label)s_%(class)s_items",
    )

I then do something like this in the template (it’s a ListView for RN objects):

{% for pr in pr_list %}
    . . .
    {% for rn in pr.rns.all %}
        . . .
        {% for tag in rn.tags.all %}
          <span class="badge bg-{{ tag.get_color_display }}">
            {{ tag.name }}
          </span>
        {% endfor %}
    {% endfor %}
{% endfor %}

This spits out the list of RNs and associated tags but the order is mixed.

Here is the RN model (some bits omitted):

class RN(abstract_base_model_factory()):
    . . .
    pr = models.ForeignKey(PR, on_delete=models.CASCADE, related_name='rns')
    tags = TaggableManager(through=ReleaseNotesTaggedItem)

    class Meta:
        verbose_name_plural = 'RNs'
        # ordering = ['order']

I should note that I’ve tried setting the ordering on all the models included in this relationship to try and coax out the tag order, but nothing seemed to work. If you have any ideas on a workaround, that would be awesome. As a total hack, I have an order field on the base class from which all my models inherit (not the custom tag, but my own models) so I’m using this to set the order of RN objects.

Also, perhaps what is making this trickier than expected is that RN has a ForeignKey relationship to another model, PR. So my ListView above is actually for PR. I’m doing this because I need to loop through PRs first, then for each PR, I need to loop through all the associated RNs (and thus tags, cause each RN has a single tag).