<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Overview of Twisted IM</title> </head> <body> <h1>Overview of Twisted IM</h1> <div class="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 <em>will</em> 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.</div> <p>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.</p> <h2>Code flow</h2> <p>Twisted IM is usually started from the file <code>twisted/scripts/im.py</code> (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. <code>im.py</code> picks an implementation and starts it - if you want to write your own interface, you can modify <code>im.py</code> to start it under appropriate conditions.</p> <p>Once started, both interfaces behave in a very similar fashion, so I won't be getting into differences here.</p> <h3>AccountManager</h3> <p>Control flow starts at the relevant subclass of <code class="API" base="twisted.im">baseaccount.AccountManager</code>. 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.</p> <p>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 <code class="API" base="twisted.im.baseaccount">AccountManager</code> are pretty self-explanatory, and your subclass can override whatever it wants, but you <em>need</em> to override <code class="python">__init__</code>. Something like this:</p> <pre class="python"> def __init__(self): self.chatui = ... # Your subclass of basechat.ChatUI self.accounts = ... # Load account list for a in self.accounts: a.logOn(self.chatui) </pre> <h3>ChatUI</h3> <p>Account objects talk to the user via a subclass of <code class="API" base="twisted.im">basechat.ChatUI</code>. 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.</p> <p>How much of this class you need to override depends on what you need to do. You will need to override <code>getConversation</code> (a one-on-one conversation, like an IRC DCC chat) and <code>getGroupConversation</code> (a multiple user conversation, like an IRC channel). You might want to override <code>getGroup</code> and <code>getPerson</code>.</p> <p>The main problem with the default versions of the above routines is that they take a parameter, <code>Class</code>, which defaults to an abstract implementation of that class - for example, <code>getConversation</code> has a <code>Class</code> parameter that defaults to <code class="API" base="twisted.im">basechat.Conversation</code> which raises a lot of <code>NotImplementedError</code>s. In your subclass, override the method with a new method whose Class parameter defaults to your own implementation of <code>Conversation</code>, that simply calls the parent class' implementation.</p> <h3>Conversation and GroupConversation</h3> <p>These classes are where your interface meets the chat protocol. Chat protocols get a message, find the appropriate <code>Conversation</code> or <code>GroupConversation</code> object, and call its methods when various interesting things happen.</p> <p>Override whatever methods you want to get the information you want to display. You must override the <code>hide</code> and <code>show</code> methods, however - they are called frequently and the default implementation raises <code>NotImplementedError</code>.</p> <h3>Accounts</h3> <p>An account is an instance of a subclass of <code class="API" base="twisted.im">basesupport.AbstractAccount</code>. For more details and sample code, see the various <code>*support</code> files in <code>twisted.im</code>.</p> </body> </html>