Validators

def validate_confusables(*, value: str, exception_class: Callable) -> None:
    """Disallows 'dangerous' usernames likely to represent homograph attacks.

    A username is 'dangerous' if it is mixed-script (as defined by
    Unicode 'Script' property) and contains one or more characters
    appearing in the Unicode Visually Confusable Characters file.

    Args:
        value: string.
        exception_class: Callable Exception class

    Examples:
        >>> from users import validators
        >>> validators.validate_confusables(value="AlaskaJazz", exception_class=ValueError)  # noqa: B950
        Traceback (most recent call last):
            ...
        ValueError: This name cannot be registered.Please choose a different name.
        >>> validators.validate_confusables(value="123", exception_class=ValueError)
        None

    Raises:
        exception_class: call the exception class if the value is dangerous.
    """
    if confusables.is_dangerous(value):
        raise exception_class(CONFUSABLE, code=_("invalid"))

def validate_confusables_email(
    *,
    local_part: str,
    domain: str,
    exception_class: Callable,
) -> None:
    """Disallows 'dangerous' email addresses likely to represent homograph attacks.

    An email address is 'dangerous' if either the local-part or the
    domain, considered on their own, are mixed-script and contain one
    or more characters appearing in the Unicode Visually Confusable
    Characters file.

    Args:
        local_part: the local part of the email addres, before @.
        domain: the domain part of the email addres, after @.
        exception_class: Callable Exception class

    Examples:
        >>> from users import validators
        >>> validators.validate_confusables_email(local_part="AlaskaJazz", domain="AlaskaJazz", exception_class=ValueError)  # noqa: B950
        Traceback (most recent call last):
            ...
        ValueError: This email address cannot be registered. Please supply a different email address.
        >>> validators.validate_confusables_email(local_part="123", domain="123", exception_class=ValueError)
        None

    Raises:
        exception_class: call the exception class if the value is dangerous.
    """
    if confusables.is_dangerous(local_part) or confusables.is_dangerous(domain):
        raise exception_class(CONFUSABLE_EMAIL, code=_("invalid"))

def validate_reserved_name(*, value: str, exception_class: Callable) -> None:
    """Disallows many reserved names as form field values.

    Args:
        value: string.
        exception_class: Callable Exception class.

    Examples:
        >>> from users import validators
        >>> validators.validate_reserved_name(value="admin", exception_class=ValueError)
        Traceback (most recent call last):
            ...
        ValueError: admin is reserved and cannot be registered.
        >>> validators.validate_reserved_name(value="123", exception_class=ValueError)
        None

    Raises:
        exception_class: call the exception class if the value is dangerous.
    """
    if value in DEFAULT_RESERVED_NAMES or value.startswith(".well-known"):
        msg = f"{value} is reserved and cannot be registered."
        raise exception_class(msg)