Encodes the username/realm/password triplet for Digest
authentication. (That is, it returns a stringified MD5 hash of
username, realm, and password concatenated together). This is
the form that is needed as the return value of
Soup.AuthDomainDigest’s auth handler.
For security reasons, you should store the encoded hash, rather
than storing the cleartext password itself and calling this method
only when you need to verify it. This way, if your server is
compromised, the attackers will not gain access to cleartext
passwords which might also be usable at other sites. (Note also
that the encoded password returned by this method is identical to
the encoded password stored in an Apache .htdigest file.)
user_data (object or None) – data to pass to auth_callback
Sets the callback that self will use to authenticate incoming
requests. For each request containing authorization, self will
invoke the callback, and then either accept or reject the request
based on callback’s return value.