Event save

event_save.py

class ModelDiffMixin(object):
    """
    Ref: https://stackoverflow.com/questions/1355150/django-when-saving-how-can-you-check-if-a-field-has-changed
    """
    def __init__(self, *args, **kwargs):
        super(ModelDiffMixin, self).__init__(*args, **kwargs)
        self.__initial = self._dict

    @property
    def _dict(self):
        return model_to_dict(
            self,
            fields=[field.name for field in self._meta.fields]
        )

    @property
    def model_diff(self):
        initial_data = self.__initial
        new_data = self._dict
        data_diff = diff(new_data, initial_data, dump=True)
        return json.loads(data_diff)

    @property
    def has_changed(self):
        return bool(self.model_diff)
    

    
class Mid(Timestampable, ModelDiffMixin, models.Model):
    ...


@receiver(post_save, sender=Mid)
def save_events(sender, instance, created, *args, **kwargs):
    user = CuserMiddleware.get_user()
    object_data = serialize('json', [instance, ])
    object_json = json.loads(object_data)
    if created:
        event_type = 'mid:created'
        save_data = object_json
        log_event(
            user=user,
            event_type=event_type,
            content_type=instance,
            event_object_id=instance.id,
            data=save_data
        )
    elif not created and instance.has_changed:
        event_type = 'mid:updated'
        previous_attributes = instance.model_diff
        object_json[0]['previous_attributes'] = previous_attributes
        save_data = object_json
        log_event(
            user=user,
            event_type=event_type,
            content_type=instance,
            event_object_id=instance.id,
            data=save_data
        )