Net::IRC - Perl interface to the Internet Relay Chat protocol

    use Net::IRC;

    $irc = new Net::IRC;
    $conn = $irc->newconn(Nick    => 'some_nick',
                          Server  => 'some.irc.server.com',
                          Port    =>  6667,
                          Ircname => 'Some witty comment.');
    $irc->start;

Welcome to Net::IRC, a work in progress. First intended to be a quick tool for writing an IRC script in Perl, Net::IRC has grown into a comprehensive Perl implementation of the IRC protocol (RFC 1459), developed by several members of the EFnet IRC channel #perl, and maintained in channel #net-irc.

There are 4 component modules which make up Net::IRC:

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Net::IRC The wrapper for everything else, containing methods to generate Connection objects (see below) and a connection manager which does an event loop on all available filehandles. Sockets or files which are readable (or writable, or whatever you want it to select() for) get passed to user-supplied handler subroutines in other packages or in user code.

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Net::IRC::Connection The big time sink on this project. Each Connection instance is a single connection to an IRC server. The module itself contains methods for every single IRC command available to users (Net::IRC isn't designed for writing servers, for obvious reasons), methods to set, retrieve, and call handler functions which the user can set (more on this later), and too many cute comments. Hey, what can I say, we were bored.

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Net::IRC::Event Kind of a struct-like object for storing info about things that the IRC server tells you (server responses, channel talk, joins and parts, et cetera). It records who initiated the event, who it affects, the event type, and any other arguments provided for that event. Incidentally, the only argument passed to a handler function.

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Net::IRC::DCC The analogous object to Connection.pm for connecting, sending and retrieving with the DCC protocol. Instances of DCC.pm are invoked from CWConnection->new_{send,get,chat} in the same way that CWIRC->newconn invokes CWConnection->new. This will make more sense later, we promise.

The central concept that Net::IRC is built around is that of handlers (or hooks, or callbacks, or whatever the heck you feel like calling them). We tried to make it a completely event-driven model, a la Tk for every conceivable type of event that your client might see on IRC, you can give your program a custom subroutine to call. But wait, there's more! There are 3 levels of handler precedence:

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Default handlers Considering that they're hardwired into Net::IRC, these won't do much more than the bare minimum needed to keep the client listening on the server, with an option to print (nicely formatted, of course) what it hears to whatever filehandles you specify (STDOUT by default). These get called only when the user hasn't defined any of his own handlers for this event.

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User-definable global handlers The user can set up his own subroutines to replace the default actions for every IRC connection managed by your program. These only get invoked if the user hasn't set up a per-connection handler for the same event.

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User-definable per-connection handlers Simple: this tells a single connection what to do if it gets an event of this type. Supersedes global handlers if any are defined for this event.

And even better, you can choose to call your custom handlers before or after the default handlers instead of replacing them, if you wish. In short, it's not perfect, but it's about as good as you can get and still be documentable, given the sometimes horrendous complexity of the IRC protocol.

To start a Net::IRC script, you need two things: a Net::IRC object, and a Net::IRC::Connection object. The Connection object does the dirty work of connecting to the server; the IRC object handles the input and output for it. To that end, say something like this:

    use Net::IRC;

    $irc = new Net::IRC;

    $conn = $irc->newconn(Nick    => 'some_nick',
                          Server  => 'some.irc.server.com');

...or something similar. Acceptable parameters to newconn() are:

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Nick The nickname you'll be known by on IRC, often limited to a maximum of 9 letters. Acceptable characters for a nickname are CW[\w{}[]\`^|-]. If you don't specify a nick, it defaults to your username.

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Server The IRC server to connect to. There are dozens of them across several widely-used IRC networks, but the oldest and most popular is EFNet (Eris Free Net), home to #perl. See http://www.irchelp.org/ for lists of popular servers, or ask a friend.

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Port The port to connect to this server on. By custom, the default is 6667.

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Username On systems not running identd, you can set the username for your user@host to anything you wish. Note that some IRC servers won't allow connections from clients which don't run identd.

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Ircname A short (maybe 60 or so chars) piece of text, originally intended to display your real name, which people often use for pithy quotes and URLs. Defaults to the contents of your GECOS field.

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Password If the IRC server you're trying to write a bot for is password-protected, no problem. Just say "CWPassword = 'foo'>" and you're set.

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SSL If you wish to connect to an irc server which is using SSL, set this to a true value. Ie: "CWSSL = 1>".

Once that's over and done with, you need to set up some handlers if you want your bot to do anything more than sit on a connection and waste resources. Handlers are references to subroutines which get called when a specific event occurs. Here's a sample handler sub:

    # What to do when the bot successfully connects.
    sub on_connect {
        my $self = shift;

        print "Joining #IRC.pm...";
        $self->join("#IRC.pm");
        $self->privmsg("#IRC.pm", "Hi there.");
    }

The arguments to a handler function are always the same:

$_[0]:

The Connection object that's calling it.

$_[1]:

An Event object (see below) that describes what the handler is responding to.

Got it? If not, see the examples in the irctest script that came with this distribution. Anyhow, once you've defined your handler subroutines, you need to add them to the list of handlers as either a global handler (affects all Connection objects) or a local handler (affects only a single Connection). To do so, say something along these lines:

    $self->add_global_handler('376', \&on_connect);     # global
    $self->add_handler('msg', \&on_msg);                # local

376, incidentally, is the server number for end of MOTD, which is an event that the server sends to you after you're connected. See Event.pm for a list of all possible numeric codes. The 'msg' event gets called whenever someone else on IRC sends your client a private message. For a big list of possible events, see the Event List section in the documentation for Net::IRC::Event.

When you've set up all your handlers, the following command will put your program in an infinite loop, grabbing input from all open connections and passing it off to the proper handlers:

    $irc->start;

Note that new connections can be added and old ones dropped from within your handlers even after you call this. Just don't expect any code below the call to CWstart() to ever get executed.

If you're tying Net::IRC into another event-based module, such as perl/Tk, there's a nifty CWdo_one_loop() method provided for your convenience. Calling CW$irc->do_one_loop() runs through the IRC.pm event loop once, hands all ready filehandles over to the appropriate handler subs, then returns control to your program.

This section contains only the methods in IRC.pm itself. Lists of the methods in Net::IRC::Connection, Net::IRC::Event, or Net::IRC::DCC are in their respective modules' documentation; just CWperldoc Net::IRC::Connection (or Event or DCC or whatever) to read them. Functions take no arguments unless otherwise specified in their description.

By the way, expect Net::IRC to use AutoLoader sometime in the future, once it becomes a little more stable.

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addconn() Adds the specified object's socket to the select loop in CWdo_one_loop(). This is mostly for the use of Connection and DCC objects (and for pre-0.5 compatibility)... for most (read: all) purposes, you can just use CWaddfh(), described below. Takes at least 1 arg:

0.

An object whose socket needs to be added to the select loop

1.

Optional: A string consisting of one or more of the letters r, w, and e. Passed directly to CWaddfh()... see the description below for more info.

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addfh() This sub takes a user's socket or filehandle and a sub to handle it with and merges it into CWdo_one_loop()'s list of select()able filehandles. This makes integration with other event-based systems (Tk, for instance) a good deal easier than in previous releases. Takes at least 2 args:

0.

A socket or filehandle to monitor

1.

A reference to a subroutine. When CWselect() determines that the filehandle is ready, it passes the filehandle to this (presumably user-supplied) sub, where you can read from it, write to it, etc. as your script sees fit.

2.

Optional: A string containing any combination of the letters r, w or e (standing for read, write, and error, respectively) which determines what conditions you're expecting on that filehandle. For example, this line select()s CW$fh (a filehandle, of course) for both reading and writing:

    $irc->addfh( $fh, \&callback, "rw" );

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do_one_loop() CWselect()s on all open filehandles and passes any ready ones to the appropriate handler subroutines. Also responsible for executing scheduled events from CWNet::IRC::Connection->schedule() on time.

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new() A fairly vanilla constructor which creates and returns a new Net::IRC object.

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newconn() Creates and returns a new Connection object. All arguments are passed straight to CWNet::IRC::Connection->new(); examples of common arguments can be found in the Synopsis or Getting Started sections.

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removeconn() Removes the specified object's socket from CWdo_one_loop()'s list of select()able filehandles. This is mostly for the use of Connection and DCC objects (and for pre-0.5 compatibility)... for most (read: all) purposes, you can just use CWremovefh(), described below. Takes 1 arg:

0.

An object whose socket or filehandle needs to be removed from the select loop

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removefh() This method removes a given filehandle from CWdo_one_loop()'s list of selectable filehandles. Takes 1 arg:

0.

A socket or filehandle to remove

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start() Starts an infinite event loop which repeatedly calls CWdo_one_loop() to read new events from all open connections and pass them off to any applicable handlers.

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timeout() Sets or returns the current CWselect() timeout for the main event loop, in seconds (fractional amounts allowed). See the documentation for the CWselect() function for more info. Takes 1 optional arg:

0.

Optional: A new value for the CWselect() timeout for this IRC object.

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flush_output_queue() Flushes any waiting messages in the output queue if pacing is enabled. This method will not return until the output queue is empty.

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Conceived and initially developed by Greg Bacon <gbacon@adtran.com> and Dennis Taylor <dennis@funkplanet.com>.

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Ideas and large amounts of code donated by Nat King Torkington <gnat@frii.com>.

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Currently being hacked on, hacked up, and worked over by the members of the Net::IRC developers mailing list. For details, see http://www.execpc.com/~corbeau/irc/list.html .

Up-to-date source and information about the Net::IRC project can be found at http://www.sourceforge.net/projects/net-irc/ .

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perl(1).

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RFC 1459: The Internet Relay Chat Protocol

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http://www.irchelp.org/, home of fine IRC resources.