web.py 文件源码

def decode_signed_value(secret, name, value, max_age_days=31,
                        clock=None, min_version=None):
    if clock is None:
        clock = time.time
    if min_version is None:
        min_version = DEFAULT_SIGNED_VALUE_MIN_VERSION
    if min_version > 2:
        raise ValueError("Unsupported min_version %d" % min_version)
    if not value:
        return None

    value = utf8(value)
    version = _get_version(value)

    if version < min_version:
        return None
    if version == 1:
        return _decode_signed_value_v1(secret, name, value,
                                       max_age_days, clock)
    elif version == 2:
        return _decode_signed_value_v2(secret, name, value,
                                       max_age_days, clock)
    else:
        return None