django patch

import datetime

import pytz
from django.apps import AppConfig
from django.db.models.fields import DateTimeField
from django.utils.dateparse import parse_date
from django.core.exceptions import ValidationError

default_app_config = 'patch.PatchConfig'


def patch():
    def get_db_prep_value(self, value, connection, prepared=False):
        if isinstance(value, str):
            if not value:
                value = None
            elif not parse_date(value):
                try:
                    value = datetime.datetime.fromtimestamp(int(value)).replace(tzinfo=pytz.UTC)
                except:
                    raise ValidationError(
                        self.error_messages['invalid'],
                        code='invalid',
                        params={'value': value},
                    )
        if not prepared:
            value = self.get_prep_value(value)
        return connection.ops.adapt_datetimefield_value(value)

    DateTimeField.get_db_prep_value = get_db_prep_value


class PatchConfig(AppConfig):
    name = 'patch'

    def ready(self):
        patch()