Request: add support for get_credential

[AlexanderLanin]

I'm attempting to store a username and a password for a specific service. As far as I can understand the get_credential function is currently not supported.

Here is my workaround, but I'd like to get rid of it ... ;-)

def _active_backend_name(user_readable=True):
    return f"{keyring.get_keyring().__module__}.{type(keyring.get_keyring()).__name__}"

def _get_credential(service: str):
    if _active_backend_name() == "keyrings.cryptfile.cryptfile.CryptFileKeyring":
        username = keyring.get_password(service, "USERNAME")
        if username:
            password = keyring.get_password(service, username)
            return SimpleCredential(username, password)
        else:
            return None
    else:
        return keyring.get_credential(service, None)


def _keyring_set(service: str, cred: SimpleCredential):
    if _active_backend_name() == "keyrings.cryptfile.cryptfile.CryptFileKeyring":
        keyring.set_password(service, "USERNAME", cred.username)
    keyring.set_password(service, cred.username, cred.password)

[frispete]

Hi Alexander,

in general, I'm in for such a change, but I don't have the time to prepare that at the moment.

Would you be so kind to prepare a PR, that implements something like this, while taking the existing class hierarchy and conformance to the predominant code style into account?