POE::Component::IRC::PUsernContributed Perl DocPOE::Component::IRC::Plugin(3p)



NAME
       POE::Component::IRC::Plugin - Provides plugin constants and
       documentation for POE::Component::IRC

SYNOPSIS
        # A simple ROT13 'encryption' plugin

        package Rot13;

        use strict;
        use warnings;
        use POE::Component::IRC::Plugin qw( :ALL );

        # Plugin object constructor
        sub new {
            my $package = shift;
            return bless {}, $package;
        }

        sub PCI_register {
            my ($self, $irc) = splice @_, 0, 2;

            $irc->plugin_register( $self, 'SERVER', qw(public) );
            return 1;
        }

        # This is method is mandatory but we don't actually have anything to do.
        sub PCI_unregister {
            return 1;
        }

        sub S_public {
            my ($self, $irc) = splice @_, 0, 2;

            # Parameters are passed as scalar-refs including arrayrefs.
            my $nick    = ( split /!/, ${ $_[0] } )[0];
            my $channel = ${ $_[1] }->[0];
            my $msg     = ${ $_[2] };

            if (my ($rot13) = $msg =~ /^rot13 (.+)/) {
                $rot13 =~ tr[a-zA-Z][n-za-mN-ZA-M];

                # Send a response back to the server.
                $irc->yield( privmsg => $channel => $rot13 );
                # We don't want other plugins to process this
                return PCI_EAT_PLUGIN;
            }

            # Default action is to allow other plugins to process it.
            return PCI_EAT_NONE;
        }

DESCRIPTION
       POE::Component::IRC's plugin system has been released separately as
       Object::Pluggable. Gleaning at its documentation is advised. The rest
       of this document mostly describes aspects that are specific to
       POE::Component::IRC's use of Object::Pluggable.

HISTORY
       Certain individuals in #PoE on MAGNet said we didn't need to bloat the
       PoCo-IRC code...

       BinGOs, the current maintainer of the module, and I heartily agreed
       that this is a wise choice.

       One example:

       Look at the magnificent new feature in 3.4 -> irc_whois replies! Yes,
       that is a feature I bet most of us have been coveting for a while, as
       it definitely makes our life easier. It was implemented in 30 minutes
       or so after a request, the maintainer said. I replied by saying that
       it's a wonderful idea, but what would happen if somebody else asked for
       a new feature? Maybe thatfeature is something we all would love to
       have, so should it be put in the core? Plugins allow the core to stay
       lean and mean, while delegating additional functionality to outside
       modules. BinGOs' work with making PoCo-IRC inheritable is wonderful,
       but what if there were 2 modules which have features that you would
       love to have in your bot? Inherit from both? Imagine the mess...

       Here comes plugins to the rescue :)

       You could say Bot::Pluggable does the job, and so on, but if this
       feature were put into the core, it would allow PoCo-IRC to be extended
       beyond our wildest dreams, and allow the code to be shared amongst us
       all, giving us superior bug smashing abilities.

       Yes, there are changes that most of us will moan when we go update our
       bots to use the new $irc object system, but what if we also used this
       opportunity to improve PoCo-IRC even more and give it a lifespan until
       Perl8 or whatever comes along? :)

DESCRIPTION
       The plugin system works by letting coders hook into the two aspects of
       PoCo-IRC:

       o   Data received from the server

       o   User commands about to be sent to the server

       The goal of this system is to make PoCo-IRC so easy to extend, enabling
       it to Take Over The World! *Just Kidding*

       The general architecture of using the plugins should be:

        # Import the stuff...
        use POE;
        use POE::Component::IRC;
        use POE::Component::IRC::Plugin::ExamplePlugin;

        # Create our session here
        POE::Session->create( ... );

        # Create the IRC session here
        my $irc = POE::Component::IRC->spawn() or die "Oh noooo! $!";

        # Create the plugin
        # Of course it could be something like $plugin = MyPlugin->new();
        my $plugin = POE::Component::IRC::Plugin::ExamplePlugin->new( ... );

        # Hook it up!
        $irc->plugin_add( 'ExamplePlugin', $plugin );

        # OOPS, we lost the plugin object!
        my $pluginobj = $irc->plugin_get( 'ExamplePlugin' );

        # We want a list of plugins and objects
        my $hashref = $irc->plugin_list();

        # Oh! We want a list of plugin aliases.
        my @aliases = keys %{ $irc->plugin_list() };

        # Ah, we want to remove the plugin
        $plugin = $irc->plugin_del( 'ExamplePlugin' );

       The plugins themselves will conform to the standard API described here.
       What they can do is limited only by imagination and the IRC RFC's ;)

        # Import the constants
        use POE::Component::IRC::Plugin qw( :ALL );

        # Our constructor
        sub new {
            ...
        }

        # Required entry point for PoCo-IRC
        sub PCI_register {
            my ($self, $irc) = @_;
            # Register events we are interested in
            $irc->plugin_register( $self, 'SERVER', qw( 355 kick whatever) );

            # Return success
            return 1;
        }

        # Required exit point for PoCo-IRC
        sub PCI_unregister {
            my ($self, $irc) = @_;

            # PCI will automatically unregister events for the plugin

            # Do some cleanup...

            # Return success
            return 1;
        }

        # Registered events will be sent to methods starting with IRC_
        # If the plugin registered for SERVER - irc_355
        sub S_355 {
            my($self, $irc, $line) = @_;

            # Remember, we receive pointers to scalars, so we can modify them
            $$line = 'frobnicate!';

            # Return an exit code
            return PCI_EAT_NONE;
        }

        # Default handler for events that do not have a corresponding plugin
        # method defined.
        sub _default {
            my ($self, $irc, $event) = splice @_, 0, 3;

            print "Default called for $event\n";

            # Return an exit code
            return PCI_EAT_NONE;
        }

       Plugins can even embed their own POE sessions if they need to do fancy
       stuff.  Below is a template for a plugin which does just that.

        package POE::Plugin::Template;

        use POE;
        use POE::Component::IRC::Plugin qw( :ALL );

        sub new {
            my $package = shift;
            my $self = bless {@_}, $package;
            return $self;
        }

        sub PCI_register {
            my ($self, $irc) = splice @_, 0, 2;

            # We store a ref to the $irc object so we can use it in our
            # session handlers.
            $self->{irc} = $irc;

            $irc->plugin_register( $self, 'SERVER', qw(blah blah blah) );

            POE::Session->create(
                object_states => [
                    $self => [qw(_start _shutdown)],
                ],
            );

            return 1;
        }

        sub PCI_unregister {
            my ($self, $irc) = splice @_, 0, 2;
            # Plugin is dying make sure our POE session does as well.
            $poe_kernel->call( $self->{SESSION_ID} => '_shutdown' );
            delete $self->{irc};
            return 1;
        }

        sub _start {
            my ($kernel, $self) = @_[KERNEL, OBJECT];
            $self->{SESSION_ID} = $_[SESSION]->ID();
            # Make sure our POE session stays around. Could use aliases but that is so messy :)
            $kernel->refcount_increment( $self->{SESSION_ID}, __PACKAGE__ );
            return;
        }

        sub _shutdown {
            my ($kernel, $self) = @_[KERNEL, OBJECT];
            $kernel->alarm_remove_all();
            $kernel->refcount_decrement( $self->{SESSION_ID}, __PACKAGE__ );
            return;
        }

EVENT TYPES
   SERVER hooks
       Hooks that are targeted toward data received from the server will get
       the exact same arguments as if it was a normal event, look at the PoCo-
       IRC docs for more information.

       NOTE: Server methods are identified in the plugin namespace by the
       subroutine prefix of S_*. I.e. an irc_kick event handler would be:

        sub S_kick {}

       The only difference is instead of getting scalars, the hook will get a
       reference to the scalar, to allow it to mangle the data. This allows
       the plugin to modify data *before* they are sent out to registered
       sessions.

       They are required to return one of the exit codes so PoCo-IRC will know
       what to do.

       Names of potential hooks

        001
        socketerr
        connected
        plugin_del
        ...

       Keep in mind that they are always lowercased. Check out the OUTPUT
       section of POE::Component::IRC's documentation for the complete list of
       events.

   USER hooks
       These type of hooks have two different argument formats. They are split
       between data sent to the server, and data sent through DCC connections.

       NOTE: User methods are identified in the plugin namespace by the
       subroutine prefix of U_*. I.e. an irc_kick event handler would be:

        sub U_kick {}

       Hooks that are targeted to user data have it a little harder. They will
       receive a reference to the raw line about to be sent out. That means
       they will have to parse it in order to extract data out of it.

       The reasoning behind this is that it is not possible to insert hooks in
       every method in the $irc object, as it will become unwieldy and not
       allow inheritance to work.

       The DCC hooks have it easier, as they do not interact with the server,
       and will receive references to the arguments specified in the DCC
       plugin documentation regarding dcc commands.

       Names of potential hooks

        kick
        dcc_chat
        ison
        privmsg
        ...

       Keep in mind that they are always lowercased, and are extracted from
       the raw line about to be sent to the irc server. To be able to parse
       the raw line, some RFC reading is in order. These are the DCC events
       that are not given a raw line, they are:

        dcc        - $nick, $type, $file, $blocksize, $timeout
        dcc_accept - $cookie, $myfile
        dcc_resume - $cookie
        dcc_chat   - $cookie, @lines
        dcc_close  - $cookie

   _default
       If a plugin has registered for an event but doesn't have a hook method
       defined for ir, component will attempt to call a plugin's "_default"
       method.  The first parameter after the plugin and irc objects will be
       the handler name.

        sub _default {
            my ($self, $irc, $event) = splice @_, 0, 3;

            # $event will be something like S_public or U_dcc, etc.
            return PCI_EAT_NONE;
        }

       The "_default" handler is expected to return one of the exit codes so
       PoCo-IRC will know what to do.

EXIT CODES
   PCI_EAT_NONE
       This means the event will continue to be processed by remaining plugins
       and finally, sent to interested sessions that registered for it.

   PCI_EAT_CLIENT
       This means the event will continue to be processed by remaining plugins
       but it will not be sent to any sessions that registered for it. This
       means nothing will be sent out on the wire if it was an USER event,
       beware!

   PCI_EAT_PLUGIN
       This means the event will not be processed by remaining plugins, it
       will go straight to interested sessions.

   PCI_EAT_ALL
       This means the event will be completely discarded, no plugin or session
       will see it. This means nothing will be sent out on the wire if it was
       an USER event, beware!

EXPORTS
       Exports the return constants for plugins to use in @EXPORT_OK Also, the
       ':ALL' tag can be used to get all of them.

SEE ALSO
       POE::Component::IRC

       Object::Pluggable

       Object::Pluggable::Pipeline

       POE::Session

AUTHOR
       Apocalypse <apocal@cpan.org>



perl v5.12.2                      2010-11-05   POE::Component::IRC::Plugin(3p)
