[Twisted-Python] Twisted Cred using network connections to check credentials

[exarkun at twistedmatrix.com]

On 03:46 pm, jeanpierreda at gmail.com wrote:
>Hello,
>
>I want to authenticate a user in twisted.cred by attempting to log him 
>in to
>an online service. If the authentication step of the connection fails, 
>the
>user gets no avatar, and if it succeeds, the user gets an avatar, and 
>that
>avatar either is or has a reference to that connection.
>
>How would I do this? I can think of two ugly ways: I can use a global
>dictionary mapping avatarIds to protocol instances, and do a lookup on 
>that
>dict in the Realm to create the avatar. Otherwise, I can instantiate 
>the
>connection as part of the credentials, and keep the reference to it 
>around
>when I get the avatar. I'm going ahead with the former, but it's scary.
>
>Another possibility is that perhaps the credentials checker and the 
>realm
>could be the same object, and then I could move the global dict into an
>attribute. Would that be a better approach?

You can do this, but you don't have to.  You can also pass the dict to 
both the checker initializer and the realm initializer.  Now they both 
have a reference to it, but it's not global, and they're still separate 
objects.

Jean-Paul
>The background for this is that I have an implementation of the chat 
>part of
>the Direct Connect (DC) protocol, and want to write an IRC<->DC bridge. 
>I
>chose twisted.words.services on the recommendation of someone, which 
>uses
>Cred for auth. DC has authentication as a given nick as part of the
>"handshake" during the start of the connection attempt.
>
>Devin Jeanpierre