لطفا منتظر باشید ...
Hack 38 Extend the Python IRCLib
Not every program needs the same features from
an IRC library. Extend IRCLib for your specific purposes.
This hack shows you how to write an
extension for IRCLib [Hack #37] .
Extensions are simply Python scripts that add events and/or methods
to the IRCLib classes. This allows you to have a modular, incremental
approach to creating bots, adding one feature at a time.
Let's take a look at an example.
5.9.1 The Code
Save
this as helloworld.py anywhere in your Python
path:
import irc
dependencies=[]
IRC_Object=None
def send_hi(self, channel):
self.send_string("PRIVMSG %s :Hello World!" % channel)
def handle_parsed(prefix, command, params):
if command=="PRIVMSG":
if params[1]=='hi':
IRC_Instance.active.events['hi'].call_listeners(params[0])
def initialize( ):
irc.IRC_Connection.send_hi=send_hi
def initialize_connection(connection):
connection.add_event("hi")
connection.events['parsed'].add_listener(handle_parsed)
The first line is the import irc needed to get
access to the IRCLib classes.
The first variable
defined in this extension script is dependencies.
If your extension depends on other extensions to work, you can put
the names of the extensions in this list. IRCLib will then load these
extensions first before loading yours.
IRC_Instance is a reference to the
IRC_Object instance in the program that is loading
your extension.
The script then continues to define four
functions:
send_hi
This function will get added to the IRC_Connection
class. It sends the string "Hello
World!" to the channel specified by
channel.
handle_parsed
This is an event handler for the 'parsed' event.
It's used to get the parsed lines from IRCLib. If
the line matches with "hi," all
listeners for the 'hi' event are called. The
destination of the message (was it said in a channel or private
message?) is given to the event handlers as the first argument. Note
that it's using
IRC_Instance.active to get the connection that
triggered the event. This variable exists so you
don't have to pass IRC_Connection
references to each event handler.
initialize
This function is called immediately after the script is loaded. This
sets the send_hi function as a method for the
class IRC_Connection.
initialize_connection
This function is called each time a new connection is created, with
the IRC_Connection instance as its only argument.
The first line of the function adds a 'hi' event
to each connection. The second line connects
'handle_parsed' to the 'parsed'
event for each connection.
5.9.2 Loading Your Extensions
Now that you have an extension,
let's use it in an IRCLib program:
import irc
def handle_hi(destination):
MyConn.send_hi(destination)
MyIRC=irc.IRC_Object( )
MyIRC.load_extension("helloworld")
MyConn=MyIRC.new_connection( )
MyConn.nick="MauBot"
MyConn.ident="maubot"
MyConn.server=("irc.oftc.net", 6667)
MyConn.realname="Hoi"
MyConn.events['hi'].add_listener(handle_hi)
while 1:
MyIRC.main_loop( )
This example doesn't contain much new code, except
for the MyIRC.load_extension("helloworld") line.
As you've probably guessed, this call loads the
'helloworld' extension. Later on in the script,
you add an event handler for the type
'hi' (added by the extension script). This causes
the 'handle_hi' method to be called whenever the
'hi' event happens. This event handler uses the
'send_hi' method (also added by the extension) to
send back a response.
5.9.3 Built-in Extensions
IRCLib comes with a number of
built-in extensions. To see a complete list of the extensions you can
load, consult the IRCLib web site at http://irclib.bitlbee.org. There are also a
number of advanced features, such as event handler priorities and the
blocking of events.
Maurits Dijkstra
