fields.py 文件源码

def _deserialize(self, value, attr, data):
        if value is None:
            return None
        if isinstance(value, DBRef):
            if self._document_cls.collection.name != value.collection:
                raise ValidationError(_("DBRef must be on collection `{collection}`.").format(
                    self._document_cls.collection.name))
            value = value.id
        elif isinstance(value, Reference):
            if value.document_cls != self.document_cls:
                raise ValidationError(_("`{document}` reference expected.").format(
                    document=self.document_cls.__name__))
            if type(value) is not self.reference_cls:
                value = self.reference_cls(value.document_cls, value.pk)
            return value
        elif isinstance(value, self.document_cls):
            if not value.is_created:
                raise ValidationError(
                    _("Cannot reference a document that has not been created yet."))
            value = value.pk
        elif isinstance(value, self._document_implementation_cls):
            raise ValidationError(_("`{document}` reference expected.").format(
                document=self.document_cls.__name__))
        value = super()._deserialize(value, attr, data)
        # `value` is similar to data received from the database so we
        # can use `_deserialize_from_mongo` to finish the deserialization
        return self._deserialize_from_mongo(value)