query.py 文件源码

def parse_nested(cls, instance, field, nested, datas):
        if field.many_to_one or field.one_to_one:
            datas = (datas, )
        ps = []

        # Fun caveat of throwing everything into JSON, it doesn't support datetimes. Everything gets sent back as iso8601 strings
        # Make a list of all fields that should be datetimes and parse them ahead of time
        dts = [i for i, f in enumerate(field.related_model._meta.concrete_fields) if isinstance(f, models.DateTimeField)]

        for data in datas or []:
            if data is None:
                ps.append(None)
                continue

            data, nested_data = data[:-len(nested) or None], data[-len(nested):]

            for i in dts:
                data[i] = util.parse_datetime(data[i])

            # from_db expects the final argument to be a tuple of fields in the order of concrete_fields
            parsed = field.related_model.from_db(instance._state.db, None, data)

            for (f, n), d in zip(nested.items(), nested_data):
                cls.parse_nested(parsed, f, n, d)

            if field.remote_field.concrete:
                setattr(parsed, field.remote_field.get_cache_name(), instance)

            ps.append(parsed)

        if (field.many_to_one or field.one_to_one) and ps:
            return setattr(instance, field.get_cache_name(), ps[0])

        if not hasattr(instance, '_prefetched_objects_cache'):
            instance._prefetched_objects_cache = {}

        if hasattr(field, 'get_accessor_name'):
            accessor_name = field.get_accessor_name()
        else:
            accessor_name = field.name

        # get_queryset() sets a bunch of attributes for us and will respect any custom managers
        instance._prefetched_objects_cache[field.name] = getattr(instance, accessor_name).get_queryset()
        instance._prefetched_objects_cache[field.name]._result_cache = ps
        instance._prefetched_objects_cache[field.name]._prefetch_done = True