Caching for GenericRelation models in Django

django_generic_relation_caching.py

from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import generic
from django.core.cache import cache
from django.dispatch import receiver

class LabelsManager(models.Manager):
    """ The manager for Label/s, as well as superclass of the RelatedManager/s of Label/s """

    def all(self):
        if hasattr(self, 'instance'):
            cache_key = '_%s_%s_%s' % (
                self.model._meta.db_table,
                self.instance.content_type.id,
                self.instance.pk
            )
            result = cache.get(cache_key)
            if result is not None:
                return result
            result = super(LabelsManager, self).all()
            cache.set(cache_key, result)
            return result
        return super(LabelsManager, self).all()


class Label(models.Model):
    objects = LabelsManager()

    name           = models.CharField(max_length=64)
    content_type   = models.ForeignKey(ContentType)
    object_id      = models.PositiveIntegerField()
    related_object = generic.GenericForeignKey('content_type', 'object_id')


@receiver(models.signals.post_save, sender=Label)
@receiver(models.signals.pre_delete, sender=Label)
def cache_invalidate_signal_handler(sender, instance, **kwargs):
    cache_key = '_%s_%s_%s' % (
        instance._meta.db_table,
        instance.content_type.id,
        instance.object_id
    )
    cache.delete(cache_key)

Will it even work?

https://github.com/django/django/blob/27c09043da52ca1f02605bf28600bfd5ace95ae4/django/db/models/manager.py#L149-L156

From Django's Source Code:

    def all(self):
        # We can't proxy this method through the `QuerySet` like we do for the
        # rest of the `QuerySet` methods. This is because `QuerySet.all()`
        # works by creating a "copy" of the current queryset and in making said
        # copy, all the cached `prefetch_related` lookups are lost. See the
        # implementation of `RelatedManager.get_queryset()` for a better
        # understanding of how this comes into play.
        return self.get_queryset()