csrf.py 文件源码

def _get_config(
    value, config_name, default=None,
    required=True, message='CSRF is not configured.'
):
    """Find config value based on provided value, Flask config, and default
    value.

    :param value: already provided config value
    :param config_name: Flask ``config`` key
    :param default: default value if not provided or configured
    :param required: whether the value must not be ``None``
    :param message: error message if required config is not found
    :raises KeyError: if required config is not found
    """

    if value is None:
        value = current_app.config.get(config_name, default)

    if required and value is None:
        raise KeyError(message)

    return value