Enhancement in most_common

[akshar-raaj]

Django tagging provides usage_for_queryset, where we can pass a queryset and it returns a list of tags associated with instances of a model contained in the given queryset. Also it annotates each Tag. https://github.com/brosner/django-tagging/blob/master/tagging/models.py#L151

Taggit provides most_common() which is very much similar to it. But taggit doesn't provide a way so that user can specify a queryset.

eg:

class Entry:
    is_published = models.BooleanField()
    tags = TaggableManager()

If I say,

Entry.tags.most_common()

it will give me the list of tags used on any instance of Entry. It will include drafts as well as published Entries.

What if I only want to get the list of tags used on Published entries, i.e the entries which have is_published=True.

[TimFletcher]

Try changing models.py to add this:

def most_common(self, **filters):
    return self.get_query_set().filter(**filters).annotate(
        num_times=models.Count(self.through.tag_relname())
    ).order_by('-num_times')

Then you can query like this:

    filters = {'is_published': True}
    tags = Entry.tags.most_common(**filters)

I'll try to roll this into a pull request if I can work out how to write a test.

[rtpg]

We have a way to pass in extra filters to most_common now, but I do basically agree that it would be cool to pass in an external queryset in general. Going to leave this one open for now