Updated version od Django CompressedJSONField

fields.py

from django.utils.text import compress_string
from django.core.serializers.json import DjangoJSONEncoder


class CompressedJSONField(models.BinaryField):
    compress = compress_string
    encoder = DjangoJSONEncoder

    @staticmethod
    def uncompress(s):
        zbuf = io.BytesIO(s)
        with gzip.GzipFile(fileobj=zbuf) as zfile:
            ret = zfile.read()
            return ret

    def is_binary(self, value):
        return value and (type(value) == bytes or isinstance(value, memoryview))

    def get_db_prep_save(self, value, connection=None):
        if value is not None:
            value = json.dumps(value, cls=self.encoder).encode('utf-8')
            value = CompressedJSONField.compress(value)
        return super().get_db_prep_save(value, connection)

    def from_db_value(self, value, expression, connection):
        if self.is_binary(value):
            value = self.uncompress(value)
            return json.loads(value.decode('utf-8'))
        return value

models.py

from django.db import models

from fields import CompressedJSONField

class MyModel(models.Model):
    price_points = CompressedJSONField(
        null=True,
        help_text='Accepts JSON, and stores compressed in database',
        # encoder=MyCustomJSONEncoder
    )

• fixed a bug that provoked recursion during delete
• simplified logic