aio-libs/aiohttp · error · ValueError

None is not allowed as password value

Error message

None is not allowed as password value

What it means

Raised by DigestAuthMiddleware.__init__ when password is None. Mirrors the login check: the password is encoded to bytes immediately, so a None value would AttributeError later; the constructor rejects it up front.

Solutions

1. Provide a concrete password string (empty string '' is accepted if you genuinely mean empty).
2. Load via a secret manager that errors on missing keys instead of returning None.
3. Validate both credentials together at the config boundary.

Example fix

// before
mw = DigestAuthMiddleware(login='user', password=os.getenv('API_PASS'))
// after
import os
mw = DigestAuthMiddleware(login='user', password=os.environ['API_PASS'])

def require_password(password):
    if password is None:
        raise ValueError('password is required')
    return password

DigestAuthMiddleware(login=login, password=require_password(password))

def is_nonnull_password(v) -> bool:
    return v is not None and isinstance(v, str)

try:
    mw = DigestAuthMiddleware(login=login, password=password)
except ValueError as e:
    if 'password' in str(e):
        raise SystemExit('API password not configured')
    raise

When it happens

Trigger: Constructing DigestAuthMiddleware(login='user', password=None). Most often the result of an env var or secret lookup returning None and being forwarded.

Common situations: Password secret not loaded (key name typo, vault path wrong). Default of None on a CLI flag. Asymmetric config where username is set but password is not.

Related errors

• None is not allowed as login value
• A ":" is not allowed in username (RFC 1945#section-11.1)
• A ":" is not allowed in login (RFC 7617#section-2)
• base_url must have a trailing '/'
• compress must be one of True, False, 'deflate', or 'gzip'

AI-assisted analysis of aio-libs/aiohttp@d041d4d0fd (2026-08-11). Data as JSON: /api/errors/6f3d95759efb03dd. Report an issue: GitHub.

Appendix: source

Thrown at aiohttp/client_middleware_digest_auth.py:206

    - 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.
        self._origin: URL | None = None

    async def _encode(self, method: str, url: URL, body: Payload | Literal[b""]) -> str:

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