[Twisted-Python] Must avatarId always be a string?

Ralph Meijer ralphm at ik.nu
Wed Jan 9 10:43:45 EST 2013

On 2013-01-09 15:40, Adi Roiban wrote:
> On 9 January 2013 15:04, Jan Urbański <wulczer at wulczer.org> wrote:
>> On 09/01/13 13:49, Peter Westlake wrote:
>>> http://twistedmatrix.com/documents/current/core/howto/cred.html says
>>> that the avatarId parameter to IRealm.requestAvatar must be a string,
>>> not even a Unicode string. I'm using LDAP for authentication, and the
>>> checker retrieves the full LDAP entry for the user as a side-effect of
>>> authentication.
>> I remember discussing this on IRC with someone not long ago and he
>> pointed me to this thread:
>> http://twistedmatrix.com/pipermail/twisted-python/2010-September/022826.html
>> I have faced a similar problem myself and after reading the code I've
>> resolved to wilfully disregarding the documentation and passing tuples
>> around, accepting that if it breaks, I get to keep both pieces.
> I am not an expert in Twisted, but from my understanding, the "string"
> requirement is there to provide a plugable interface. So that you can
> have generic credentials checkers, working with generic realms.
> Having simple "strings" could also help with AvatarId serialization,
> in case you have the CredentialsChecker on one computer and the you
> will pass them over network/socket to a remote Realm.
> I have also asked over IRC and I got the good to go answer for using
> anything as AvatarID.
> As long as you are only using your custom credentials checkers and
> your custom realm, everything should be ok.
> I am using Objects as AvatarID without any problems.

I want to add here that the special avatarID for anonymous 
authenticationm, twisted.cred.checkers.ANONYMOUS, is defined as the 
empty tuple.


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