[Django]-In Django, how do I gracefully add a queryset filter to a large group or all members of an object?

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3👍

✅

You’re looking for model managers.

Something like:

class MediaItemManager(models.Manager):
    def get_queryset(self):
        return super(MediaItemManager, self).get_queryset().filter(...)

You can set that as the default manager on your model like this:

class MediaItem(models.Model):
    objects = MediaItemManager()
    all_objects = models.Manager()

You can ensure this doesn’t affect the admin by specifying get_queryset on your ModelAdmin subclass:

class MyModelAdmin(admin.ModelAdmin):
    def get_queryset(self, request):
        qs = self.model.all_objects.get_queryset()
        ordering = self.get_ordering(request)
        if ordering:
            qs = qs.order_by(*ordering)
        return qs

This is fairly unfortunate duplication of the base get_queryset method, since there’s no way to override the admin’s manager explicitly. A better alternative would probably be to name your custom manager filtered_objects, and use the default manager as objects.

👤Dominic Rodger

3👍

That is exactly what custom model managers are for. Define a manager subclass and override get_query_set with your query. Then, you’ll need to explicitly define a default manager first, then call your custom one objects, and it should just work.

Note, even though you can do this, I would advise against it. At the very least, call your custom manager something else – eg restricted – and do a search and replace across your code to replace references to objects to the custom version. That allows people reading your codeto realise that the query is not the standard one.

👤Daniel Roseman

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