Function _authenticate_scram_start

pymongo/auth_shared.py:240–255

(
    credentials: MongoCredential, mechanism: str
)

def _authenticate_scram_start(
    credentials: MongoCredential, mechanism: str
) -> tuple[bytes, bytes, typing.MutableMapping[str, Any]]:
    username = credentials.username
    user = username.encode("utf-8").replace(b"=", b"=3D").replace(b",", b"=2C")
    nonce = standard_b64encode(os.urandom(32))
    first_bare = b"n=" + user + b",r=" + nonce

    cmd = {
        "saslStart": 1,
        "mechanism": mechanism,
        "payload": Binary(b"n,," + first_bare),
        "autoAuthorize": 1,
        "options": {"skipEmptyExchange": True},
    }
    return nonce, first_bare, cmd