aio-libs/aiohttp · error · ValueError

None is not allowed as login value

Error message

None is not allowed as login value

What it means

Raised in `DigestAuthMiddleware.__init__` (client_middleware_digest_auth.py:202-203) when `login` is None. The middleware encodes the login to bytes immediately (line 212) and uses it in every digest computation, so a None login cannot proceed. The check is an explicit fail-fast before any encoding happens.

Source

Thrown at aiohttp/client_middleware_digest_auth.py:203

    Standards compliance:
    - RFC 7616: HTTP Digest Access Authentication (primary reference)
    - RFC 2617: HTTP Authentication (deprecated by RFC 7616)
    - RFC 1945: Section 11.1 (username restrictions)

    Implementation notes:
    The core digest calculation is inspired by the implementation in
    https://github.com/requests/requests/blob/v2.18.4/requests/auth.py
    with added support for modern digest auth features and error handling.
    """

    def __init__(
        self,
        login: str,
        password: str,
        preemptive: bool = True,
    ) -> None:
        if login is None:
            raise ValueError("None is not allowed as login value")

        if password is None:
            raise ValueError("None is not allowed as password value")

        if ":" in login:
            raise ValueError('A ":" is not allowed in username (RFC 1945#section-11.1)')

        self._login_str: Final[str] = login
        self._login_bytes: Final[bytes] = login.encode("utf-8")
        self._password_bytes: Final[bytes] = password.encode("utf-8")

        self._last_nonce_bytes = b""
        self._nonce_count = 0
        self._challenge: DigestAuthChallenge = {}
        self._preemptive: bool = preemptive
        # Set of URLs defining the protection space
        self._protection_space: list[str] = []
        # Origin the credentials are scoped to; set on the first request.

View on GitHub (pinned to c0ef574e29)

Solutions

1. Ensure `login` is a non-None string before constructing the middleware.
2. Load credentials with a required-default: `login = os.environ['DIGEST_USER']` (raises KeyError early) or `os.environ.get('DIGEST_USER', '')`.
3. Conditionally apply the middleware only when credentials are present.

Example fix

// before
mw = DigestAuthMiddleware(login=os.environ.get('USER'), password=pw)
// after
user = os.environ.get('DIGEST_USER')
if user is None:
    raise RuntimeError('DIGEST_USER must be set')
mw = DigestAuthMiddleware(login=user, password=pw)

def require_login(login: str | None) -> str:
    if login is None:
        raise ValueError('login must not be None')
    return login

def is_valid_login(v) -> bool:
    return isinstance(v, str)

When it happens

Trigger: Constructing `DigestAuthMiddleware(login=None, password='x')`; reading credentials from an env var or config that returned None; passing `login=None` as a placeholder.

Common situations: Env/config-driven credential loading where the login key is missing (returns None); test code stubbing credentials as None; conditional auth code that constructs the middleware even when credentials aren't set.

Related errors

• None is not allowed as password value
• A ":" is not allowed in username (RFC 1945#section-11.1)
• Malformed Digest auth challenge: Missing 'realm' parameter
• Malformed Digest auth challenge: Missing 'nonce' parameter
• base_url must have a trailing '/'

AI-assisted analysis of aio-libs/aiohttp@c0ef574e29 (2026-08-04). Data as JSON: /data/errors/f5d0d6f70264847f.json. Report an issue: GitHub.