Twisted Documentation: Overview of Twisted IM

Note: Twisted IM and Twisted Words are both known to be in a state of flux at the moment. Several of the APIs discussed here have fallen short of their original goals and will be changing within the next few releases of Twisted. The good news is that newer versions will be based on our experiences with the current ones and will provide much more access to features beyond plain-text chat message relaying in different protocols.

Twisted IM (Instance Messenger) is a multi-protocol chat framework, based on the Twisted framework we've all come to know and love. It's fairly simple and extensible in two directions - it's pretty easy to add new protocols, and it's also quite easy to add new front-ends.

Code flow

Twisted IM is usually started from the file twisted/scripts/im.py (maybe with a shell-script wrapper or similar). Twisted currently comes with two interfaces for Twisted IM - one written in GTK for Python under Linux, and one written in Swing for Jython. im.py picks an implementation and starts it - if you want to write your own interface, you can modify im.py to start it under appropriate conditions.

Once started, both interfaces behave in a very similar fashion, so I won't be getting into differences here.

AccountManager

Control flow starts at the relevant subclass of baseaccount.AccountManager. The AccountManager is responsible for, well, managing accounts - remembering what accounts are available, their settings, adding and removal of accounts, and making accounts log on at startup.

This would be a good place to start your interface, load a list of accounts from disk and tell them to login. Most of the method names in AccountManager are pretty self-explanatory, and your subclass can override whatever it wants, but you need to override __init__. Something like this:

def __init__(self):
	self.chatui = ... # Your subclass of basechat.ChatUI
 self.accounts = ... # Load account list
 for a in self.accounts:
		a.logOn(self.chatui)

ChatUI

Account objects talk to the user via a subclass of basechat.ChatUI. This class keeps track of all the various conversations that are currently active, so that when an account receives and incoming message, it can put that message in its correct context.

How much of this class you need to override depends on what you need to do. You will need to override getConversation (a one-on-one conversation, like an IRC DCC chat) and getGroupConversation (a multiple user conversation, like an IRC channel). You might want to override getGroup and getPerson.

The main problem with the default versions of the above routines is that they take a parameter, Class, which defaults to an abstract implementation of that class - for example, getConversation has a Class parameter that defaults to basechat.Conversation which raises a lot of NotImplementedErrors. In your subclass, override the method with a new method whose Class parameter defaults to your own implementation of Conversation, that simply calls the parent class' implementation.

Conversation and GroupConversation

These classes are where your interface meets the chat protocol. Chat protocols get a message, find the appropriate Conversation or GroupConversation object, and call its methods when various interesting things happen.

Override whatever methods you want to get the information you want to display. You must override the hide and show methods, however - they are called frequently and the default implementation raises NotImplementedError.

Accounts

An account is an instance of a subclass of basesupport.AbstractAccount. For more details and sample code, see the various *support files in twisted.im.