validators.py 文件源码

def validate_user_name(ctx, param, value: str) -> str:
    """Validates if ``value`` is a correct user name.


    Parameters
    ----------
    value : str
        Possible user name.

    Returns
    -------
    value : str
        Valid user name.

    Raises
    ------
    click.BadParameter
        If user name is not valid for unix systems.

    """
    if re.fullmatch(r'^[a-z][a-z0-9_]{5,}', value):
        return value
    else:
        raise click.BadParameter(
            'User names can only contain 0-9, a-z and _.')