IRC Hacks [Electronic resources] نسخه متنی

Hack 37 IRC with Python and IRCLib

Rather than reinventing the wheel each time you
want to make a Python IRC bot, use an IRC library such as the IRCLib
module.

While
IRCLib is relatively new and doesn't have support
for the entire IRC protocol yet, it offers a powerful API. It also
has support for extensions so a programmer can add his own events and
functions to the library. The latest IRCLib can be downloaded from
http://irclib.bitlbee.org.

We'll assume you already know how to install Python
modules, since explaining that is beyond the scope of this book. To
find out how to install modules, take a look at the excellent
documentation available at http://www.python.org/topics/learn.

5.8.1 The Code

Writing
clients with IRCLib is really easy. Take a look at the following
example:

import irc
MyIRC=irc.IRC_Object( )
MyConn=MyIRC.new_connection( )
MyConn.nick="MauBot"
MyConn.ident="maubot"
MyConn.server=("irc.freenode.net", 6667)
MyConn.realname="Maurits his bot"
while 1:
MyIRC.main_loop( )

The first line of this example imports the irc
module. You need this line to be able to use any of
IRCLib's functions and classes.

The script starts by creating an instance of the
IRC_Object class. This class could be seen as the
main object of IRCLibit creates and destroys connections and
lets them know when there's data to read and write.
The next line creates an instance of the
IRC_Connection class. This class represents a single
connection to an IRC server (a single client). You can create as many
connections as you like.

The next block of code sets the client information for the connection
you just created. nick is the nickname to use on
IRC, ident is the Ident part of your host mask
(nick!ident@host), server is
the server to connect to, and realname is the name
you want to show when somebody performs a /whois
on you.

The rest of the program just sets the IRC client in action,
connecting to the server you specified and doing whatever you told it
to do (in this case, nothing).

5.8.2 Event Handlers

Having an IRC bot is fantastic, but
what's the point if it doesn't do
anything? To allow a client to respond to things that happen on IRC,
IRCLib uses an event model. Again, it's probably
best to demonstrate this by adding some functionality to our previous
example:

import irc
# Define event listeners.
def handle_state(newstate):
if newstate==4:
MyConn.send_string("JOIN #irchacks")
def handle_raw(line):
print line
def handle_parsed(prefix, command, params):
if command=="PRIVMSG":
if(params[0]=="#irchacks" and params[1]=="hi"):
MyConn.send_string("PRIVMSG #irchacks :Hello World!")
# Connect as usual.
MyIRC=irc.IRC_Object( )
MyConn=MyIRC.new_connection( )
MyConn.nick="MauBot"
MyConn.ident="maubot"
MyConn.server=("irc.freenode.net", 6667)
MyConn.realname="Hoi"
# Before starting the main loop, add the event listeners.
MyConn.events['state'].add_listener(handle_state)
MyConn.events['raw'].add_listener(handle_raw)
MyConn.events['parsed'].add_listener(handle_parsed)
while 1:
MyIRC.main_loop( )

The program now starts by defining the event handlers. Event handlers
are functions that are called each time an event of a specific type
occurs. This bot will listen for three different events:

State

This handler lets you check the bot's current
connection state . This is used to see when
the client is connected (state 4).

Raw

This one is used to print whatever the
client is reading from the server. This is useful for debugging
purposes.

Parsed

This one is used to receive parsed
irc commands, sent to the client by the server.
This is probably the most useful event. In this case, the bot is
waiting to receive a message saying
"hi" in the channel #irchacks.
Whenever this message is received, the bot will send the message
"Hello World" back to the channel.

Before the bot enters its main loop, you must connect the event
handlers to their specified events. With these three lines,
you're telling IRCLib to call the correct event
handler whenever an event of the specified type occurs.

5.8.3 Learning More About IRCLib

So, that's all the code
that is needed to write a simple IRC bot. For a complete overview of
all the things IRCLib can do, see the documentation at http://irclib.bitlbee.org. If you want to
learn about writing an extension for IRCLib, this is detailed in the
following hack.

Maurits Dijkstra