Jon Portnoy > Bot-Cobalt > Bot::Cobalt::Manual::Plugins

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NAME ^

Bot::Cobalt::Manual::Plugins - Bot::Cobalt plugin authoring reference

DESCRIPTION ^

This POD attempts to be a reasonably complete guide to writing Bot::Cobalt plugins.

For a quick-start guide, try Bot::Cobalt::Manual::Plugins::Tutorial.

Refer to "SEE ALSO" for other relevant documentation, such as instructions on packaging up your plugin for installation.

Plugin authors likely want to at least read the Bot::Cobalt::IRC POD.

PLUGIN FUNDAMENTALS ^

A basic plugin outline

  package Bot::Cobalt::Plugin::User::MyPlugin;
  our $VERSION = '0.001';

  use strict;
  use warnings;

  ## Import some helpful sugar:
  use Bot::Cobalt;

  ## Import useful constants and utilities:
  use Bot::Cobalt::Common;
  
  ## Minimalist object constructor:
  sub new { bless {}, shift }
  
  ## Called when we are loaded:
  sub Cobalt_register {
    ## Handlers receive $self and $core as first two args:
    ##  $self is "this object"
    ##  $core gives us access to core attributes and methods
    ##  (Since we have Bot::Cobalt, core() is the same thing.)
    my ($self, $core) = splice @_, 0, 2;
    
    ## Register to only receive public msg events
    ## (We could also register for a list or 'all')
    ## Uses register() sugar from Bot::Cobalt
    register( $self, 'SERVER',
      'public_msg'
    );
    
    ## Log that we're here now:
    logger->info("Registered");

    ## Always return an Object::Pluggable::Constants value from an 
    ## event handler.
    ##
    ## (Importing Bot::Cobalt::Common will pull _NONE and _ALL in)
    ## See "Returning proper values" under "Handling events"
    ## 
    ## PLUGIN_EAT_NONE is the most common:
    return PLUGIN_EAT_NONE
  }
  
  ## Called when we are unloaded:
  sub Cobalt_unregister {
    my ($self, $core) = splice @_, 0, 2;

    . . . do some clean up, perhaps . . .
    
    logger->info("Unregistering; bye!");

    return PLUGIN_EAT_NONE
  }
  
  ## Syndicated events become prefixed with 'Bot_' when dispatched
  sub Bot_public_msg {
    my ($self, $core) = splice @_, 0, 2;

    ## Receives a Bot::Cobalt::IRC::Message::Public object:
    my $msg     = ${ $_[0] };

    my $context  = $msg->context;
    my $as_array = $msg->message_array;

    . . . do something with message @$as_array . . .

    return PLUGIN_EAT_NONE 
  }
  
  1;  ## perl modules end in '1'

Module paths and configuration

plugins.conf

plugins.conf is YAML in the following structure:

  ---
  MyPlugin:
    Module: Bot::Cobalt::Plugin::User::MyPlugin
    Config: plugins/mine/myplugin.conf
    ## Enable to skip runtime auto-loading:
    #NoAutoLoad: 1
    ## Optional, overrides Config: file:
    Opts:
      Level: 2

Configuration files specified in 'Config: ' are expected to be valid YAML1.0. You can read more about YAML at http://www.yaml.org -- for the most part, the basics are fairly self-explanatory. See Bot::Cobalt::Manual::Plugins::Config for more about simple YAML syntax for plugin configuration files.

Accessing plugin configuration

The normal way to access a plugin's configuration structure is via the core method get_plugin_cfg (or "plugin_cfg" in Bot::Cobalt::Core::Sugar):

  ## Our $self object or our alias must be specified:
  my $plug_cf = core()->get_plugin_cfg( $self );
  
  ## ... or with Bot::Cobalt sugar:
  use Bot::Cobalt;
  my $plug_cf = plugin_cfg($self);

See also: "Core methods"

These accessors will return the opts hash from the plugin's configuration object. The per-plugin configuration object itself is a Bot::Cobalt::Conf::File::PerPlugin and can be accessed via the core's Bot::Cobalt::Conf::File::Plugins instance:

  my $plug_alias  = core()->get_plugin_alias( $self );
  my $plug_cf_obj = core()->cfg->plugins->plugin( $plug_alias );

  my $module = $plug_cf_obj->module;
  
  my $opts = $plug_cf_obj->opts;
  ## Same as:
  my $opts = plugin_cfg( $self );

See the documentation for Bot::Cobalt::Conf::File::PerPlugin for more details.

Handling events

Plugins are event driven.

A plugin will (usually at load-time) register to receive some set of events, which are pushed through the plugin pipeline by the Cobalt core (with help from POE::Component::Syndicator and Object::Pluggable).

Pipeline priority is initially chosen via Priority: directives in plugins.conf; however, online plugin loads/unloads can alter the pipeline order. If your plugin needs to have a certain priority in the pipeline, you are likely going to want to spend some quality time reading the Object::Pluggable and especially Object::Pluggable::Pipeline documentation. The methods described regarding pipeline manipulation are available via core().

Registering for events

Registering for events typically happens at plugin load-time; in other words, inside Cobalt_register:

  my ($self, $core) = @_;

  ## Using Bot::Cobalt sugar:
  register( $self, 'SERVER', 
      'chan_sync',
      'public_msg',
  );

  ## Same thing without sugar:
  $core->plugin_register( $self, 'SERVER',
      'chan_sync',
      'public_msg',
  );

Event handlers

Events from IRC and internal events are classified as 'SERVER' events. Syndicated SERVER event handlers are prefixed with 'Bot_':

  sub Bot_some_event {
    my ($self, $core) = splice @_, 0, 2;
    my $deref_first_arg = ${ $_[0] };

    . . .
  }

The arguments passed to event handlers are always references. (Sometimes, they're references to references, such as a hashref. If you don't know what that means, it's time to stop here and read perlreftut & perlref)

Sending events

Events can be broadcast to the plugin pipeline via either the Core method send_event:

  $core->send_event( $event, @args );

... or via exported sugar from Bot::Cobalt::Core::Sugar (broadcast):

  use Bot::Cobalt;
  
  broadcast $event, @args;

Returning proper values

The plugin system is a pipeline, usually beginning with the Bot::Cobalt::IRC plugin. Events will be handed on down the pipeline, unless a handler for a syndicated event returns a PLUGIN_EAT_ALL or PLUGIN_EAT_PLUGIN value.

Your Bot_* event handlers should return an Object::Pluggable::Constants value. The two commonly used values are:

PLUGIN_EAT_NONE

Allow the event to continue to pass through the pipeline.

This is the most common return value for event handlers

PLUGIN_EAT_ALL

Eat the event, removing it from the plugin pipeline.

Typically you might return PLUGIN_EAT_ALL on self-syndicated events (that is to say, events the plugin intends for itself to handle, such as a Bot::Cobalt::Plugin::WWW response, timed event, event-aware loop as described in "ADVANCED CONCEPTS", etc).

This can also be useful when there is a good reason to terminate an event's lifetime; for example, implementing a plugin that loads itself at the front of the pipeline and restricts outgoing events based on some criteria.

USING IRC ^

Receiving IRC events

See Bot::Cobalt::IRC for a complete list of IRC events and their event syntax.

Understanding server context

IRC-driven events come with a 'server context' attached, mapping the server's configured "name" to server state information and allowing a plugin to make sure responses get to the right place.

For example, when receiving a public message:

  sub Bot_public_msg {
    my ($self, $core) = splice @_, 0, 2;

    ## Get this message's server context
    my $msg     = ${ $_[0] };    
    my $context = $msg->context;
    
    ## ... later, when sending a response ...
    my $channel = $msg->channel;

    broadcast( 
      'message',   ## send_event 'message'
      $context,    ## make sure it goes to the right server
      $channel,    ## destination channel on specified context
      $response,   ## some response string
    );
  }

IRC-related events always come from or are sent to a specific context.

Each context also has a Bot::Cobalt::IRC::Server object; it can be used to retrieve context-specific metadata such as connected status and the named server's announced casemapping. See "get_irc_server".

Messages

The most common use-case for an IRC bot is, of course, responding to messages.

Incoming messages are handled by Bot_public_msg and Bot_private_msg plugin event handlers. (If they are prefixed by our CmdChar, they'll also trigger a Bot_public_cmd_ event -- see "Commands", below).

A _msg event is passed a context and a Bot::Cobalt::IRC::Message object:

  sub Bot_public_msg {
    my ($self, $core) = splice @_, 0, 2;
    
    my $msg     = ${ $_[0] };
    
    my $context  = $msg->context;
    my $channel  = $msg->channel;
    my $src_nick = $msg->src_nick;
    
    . . .
    
    return PLUGIN_EAT_NONE
  }

See Bot::Cobalt::IRC::Event, Bot::Cobalt::IRC::Message and Bot::Cobalt::IRC::Message::Public for the complete documentation regarding message object methods. The most commonly-used message methods are:

target

The (first-seen) destination of the message.

channel

If a message appears to have been delivered to a channel, the channel method will return the same value as target -- otherwise it will return an empty string.

src_nick

The nickname of the sender.

src_user

The username of the sender.

src_host

The hostname of the sender.

message

The original, unparsed message text.

stripped

The color/formatting-stripped message text.

message_array

The content of the message as an array, split on white space.

message_array_sp

Similar to message_array, except spaces are preserved, including leading spaces.

Note that a '/ME' is a CTCP ACTION and not handled by _msg handlers. For that, you'll need to catch Bot_ctcp_action, which carries essentially the same syntax.

Additionally, a '/NOTICE' is not a _msg. Bot_got_notice also carries the same syntax.

See Bot::Cobalt::IRC for more details.

Commands

A Bot::Cobalt instance has a CmdChar, usually defined in etc/cobalt.conf. When any user issues a command prefixed with the bot's CmdChar, the event public_cmd_$CMD is broadcast in place of a public_msg event.

  <JoeUser> !shorten http://www.cobaltirc.org/dev/bots
  ## -> event 'Bot_public_cmd_shorten'

The command is automatically lowercased before being transformed into an event.

A plugin can register to receive commands in this format:

  ## in Cobalt_register, usually:
  register( $self, 'SERVER',
    ## register to receive the 'shorten' command:
    'public_cmd_shorten',
  );
  
  ## handler for same:
  sub Bot_public_cmd_shorten {
    my ($self, $core) = splice @_, 0, 2;
    my $msg = ${ $_[0] };
    
    ## since this is a command, our message_array is shifted
    ## the command will be stripped
    my $args = $msg->message_array;
    
    . . . 
    
    ## if this command is "ours" we might want to eat it:
    return PLUGIN_EAT_ALL
  }

It's important to note that $msg->message_array is shifted leftwards in public_cmd_ handlers; it won't contain the CmdChar-prefixed command. $msg->message_array_sp remains unchanged, as do the message and stripped strings.

Other events

Most of the typical instances of "stuff going on" on IRC are reported by the core IRC module.

The documentation for all events parsed and re-broadcast from IRC is available via the Bot::Cobalt::IRC POD.

Sending IRC events

Bot::Cobalt::IRC receives the following commonly-used events:

Sending messages

message

The message event triggers an IRC PRIVMSG to either a channel or user.

The arguments specify the server context, target (user or channel), and string, respectively:

  broadcast( 'message',
    $context, $target, $string
  );

The message will be sent after being processed by any Outgoing_message handlers in the pipeline. See Bot::Cobalt::IRC for more about Outgoing_* handlers.

notice

notice operates essentially the same as "message", except a NOTICE is sent (rather than PRIVMSG).

Event arguments are the same.

action

action sends a CTCP ACTION rather than a normal PRIVMSG or NOTICE string.

Event arguments are the same as "message" and "notice".

Channel-related commands

The following common IRC commands are handled.

Like any other interaction, they are sent as events:

  ## (attempt to) join a channel on $context:
  broadcast( 'join', $context, $channel );

See Bot::Cobalt::IRC for event argument syntax and details.

Accessing the IRC component directly

The IRC backend for the core distribution is POE::Component::IRC, more specifically the POE::Component::IRC::State subclass.

POE::Component::IRC is a very mature and complete IRC framework.

If your plugin does any kind of IRC-related heavy lifting, you will almost certainly want to consult the documentation for POE::Component::IRC and POE::Component::IRC::State.

Obtaining the IRC component

You can retrieve the IRC component object for direct access via the core's get_irc_obj method. Expects a server context:

  sub Bot_public_msg {
    my ($self, $core) = @_;
    my $msg     = ${$_[0]};
    my $context = $msg->context;
    
    my $irc = $core->get_irc_obj($context);
    . . .
  }

See POE::Component::IRC and POE::Component::IRC::State for details on using the IRC Component object directly.

USING THE CORE ^

Core methods

The Cobalt core provides various convenience accessors and methods for plugins.

The object reference to the Cobalt core object is referred to here as $core.

Bot::Cobalt::Core is actually an instanced singleton; it can be retrieved from any loaded plugin via instance:

  require Bot::Cobalt::Core;
  
  my $core = Bot::Cobalt::Core->instance;

... or 'use Bot::Cobalt' and thereby import the Bot::Cobalt::Core::Sugar wrappers:

  use Bot::Cobalt;
  
  my $irc_obj = core()->get_irc_object($context);

See the documentation for Bot::Cobalt::Core::Sugar for the complete list of exported wrappers.

Attributes

Provided

The Provided hash allows plugins to declare that some functionality or event provided by the plugin is available (for example, the $core->Provided->{www_request} element is boolean true if Bot::Cobalt::Plugin::WWW is registered).

This is useful when your plugin provides some event interface usable by other plugins, or when the presence of this plugin may alter another plugin's behavior.

A plugin should declare its Provided functionality at register-time:

  sub Cobalt_register {
    my ($self, $core) = splice @_, 0, 2;
    
    ## ... register for events, etc ...
  
    ## declare that 'tasty_snacks' functionality is available
    ## this example does nothing if it's already defined (//):
    $core->Provided->{tasty_snacks} //= 1;
    
    return PLUGIN_EAT_NONE
  }

The core has no way of automatically knowing that this functionality disappears when your plugin does. You should delete the Provided element in your _unregister:

  sub Cobalt_unregister {
    my ($self, $core) = splice @_, 0, 2;
    
    delete $core->Provided->{tasty_snacks};
    
    $core->log->info("Bye!");
    return PLUGIN_EAT_NONE
  }

Some plugins use this to share simple bits of state information in addition to their advisory nature; for example, Bot::Cobalt::Plugin::RDB shares the number of items in the 'main' RDB via the integer value of $core->Provided->{randstuff_items}.

Therefore, when attempting to determine whether a specific piece of functionality is available, it may be advisable to check for 'defined' status instead of boolean value:

  if ( defined $core->Provided->{randstuff_items} ) {
    ## we have RDB.pm
  }

Since plugin load order is generally not guaranteed and plugins may be dynamically (un)loaded, it is good practice to only check for Provided functionality in the narrowest possible scope; that is to say, directly prior to execution of the dependent code, rather than at plugin register-time.

Servers

$core->Servers is a hashref keyed on server "context" name; see "Understanding server context".

You should probably be using "get_irc_server".

  ## Iterate all contexts:
  for my $context ( keys %{ $core->Servers } ) {
    . . .
  }

The values are Bot::Cobalt::IRC::Server objects.

var

Returns the path to the current VAR dir, typically used for log files, databases, or other potentially dynamic data.

Plugins should typically dump serialized data and place databases in a path under $core->var.

version

Returns the current Bot::Cobalt::Core version.

detached

Returns a boolean value indicating whether or not this Cobalt instance is attached to a terminal or daemonized.

Configuration-related methods

get_channels_cfg

Retrieves per-context channel configuration from channels.conf:

  my $chan_cf = $core->get_channels_cfg( $context );

The server context must be specified.

Returns an empty hash if there is no channel configuration for this server context.

get_core_cfg

Retrieves the 'core' configuration object (Bot::Cobalt::Conf::File::Core), representing the "cobalt.conf" configuration values:

  my $core_cf = $core->get_core_cfg();
  my $lang    = $core_cf->language;

See Bot::Cobalt::Conf::File::Core for more details.

get_plugin_cfg

Retrieves the configuration hash for a specific plugin:

  my $plug_cf = $core->get_plugin_cfg( $self ) || {};

Either the plugin's $self object or its current alias must be specified.

  $core->log->warn("Missing config!")
    unless $core->get_plugin_cfg($self);

If you 'use Bot::Cobalt' you can make use of the exported plugin_cfg wrapper (see Bot::Cobalt::Core::Sugar):

  logger->warn("Missing config!")
    unless plugin_cfg($self);

get_plugin_alias

Retrieve a plugin object's alias

Your plugin's $self object can be specified to get the current plugin alias, for example:

  my $plugin_alias = $core->get_plugin_alias($self);

A wrapper is provided if you use 'Bot::Cobalt' (see Bot::Cobalt::Core::Sugar):

  my $plugin_alias = plugin_alias($self);

IRC-related methods

get_irc_casemap

Retrieves the CASEMAPPING rules for the specified server context, which should be one of rfc1459, strict-rfc1459, ascii :

  my $casemapping = $core->get_irc_casemap( $context );

The server's casemapping is usually declared in ISUPPORT (numeric 005) upon connect and can be used to establish whether or not the character sets {}|^ are equivalent to []\~ -- see "IRC CAVEATS" below for more information.

This can be used to feed the lc_irc/uc_irc/eq_irc functions from IRC::Utils (or Bot::Cobalt::Common and determine issues like nickname equivalency:

  use Bot::Cobalt::Common;
  my $casemapping = $core->get_irc_casemap( $context );
  my $irc_lower = lc_irc($nickname, $casemapping);
  my $is_eqal   = eq_irc($old, $new, $casemapping);

get_irc_obj

  my $irc = $core->get_irc_obj( $context );

Retrieve the POE::Component::IRC object for a specified context, which is likely to actually be a POE::Component::IRC::State instance.

This can be used to query or post events to the IRC component directly.

See the POE::Component::IRC and POE::Component::IRC::State docs for more on interacting directly with the IRC component.

get_irc_server

  my $server_state = $core->get_irc_server( $context );

Can also be called via get_irc_context.

Retrieves the appropriate Bot::Cobalt::IRC::Server object from <$core-Servers>>.

A server context must be specified.

See Bot::Cobalt::IRC::Server for details on methods that can be called against server context objects.

Auth-related methods

The Core provides access to a Bot::Cobalt::Core::ContextMeta::Auth object; methods can be called to determine user authorization levels. These are the most commonly used methods; see Bot::Cobalt::Core::ContextMeta and Bot::Cobalt::Core::ContextMeta::Auth for more.

level

Retrieves the user's authorized level (or '0' for unauthorized users).

Requires a context and a nickname:

  ## inside a msg or command handler, f.ex:
  my ($self, $core) = splice @_, 0, 2;
  my $msg     = ${ $_[0] };
  my $context = $msg->context;
  my $nick    = $msg->src_nick;
  my $level   = $core->auth->level($context, $nick);

Auth levels are fairly flexible; it is generally a good idea for your plugin to provide some method of configuring required access levels, either via a configuration file or a Opts directive in plugins.conf.

username

Retrieves the "username" for an authorized user (or empty list if the user is not currently authorized).

Requires a context and a nickname, similar to "level":

  my $username = core()->auth->username($context, $nick);
  unless ($username) {
    ## this user isn't authorized
  }

Logging

The Cobalt core provides a log method that writes to the LogFile specified in cobalt.conf (and possibly STDOUT, if running with --nodetach).

This is actually a Bot::Cobalt::Logger instance, so all methods found there apply. Typically, plugins should log to info, warn, or debug:

  core()->log->info("An informational message");
  
  core()->log->warn("Some error occured");

  core()->log->debug("some verbose debug output for --debug");

A plugin should at least log to info when it is registered or unregistered; that is to say, inside Cobalt_register and Cobalt_unregister handlers.

Timers

Core timers live in core()->TimerPool; if need be, you can access the timer pool directly. It is a hash keyed on timer ID.

Timer methods are provided by the Bot::Cobalt::Core::Role::Timers role. Each individual timer is a Bot::Cobalt::Timer object; if you plan to manipulate a created timer, you'll likely want to consult that POD.

Typically most plugins will only need the following functionality; this only covers the hash-based interface to "timer_set" in Bot::Cobalt::Core::Role::Timers, so review the aforementioned documentation if you'd like to use the object interface instead.

timer_set

Set up a new timer for an event or message.

  ## Object interface:
  core()->timer_set( $timer_object );

  ## Hash interface:
  core()->timer_set( $delay, $ev_hash );
  core()->timer_set( $delay, $ev_hash, $id );

Returns the timer ID on success, boolean false on failure.

Expects at least a delay (in seconds) and a hashref specifying what to do when the delay has elapsed.

  ## New 60 second 'msg' timer with a random unique ID:
  ## Send $string to $channel on $context
  ## (A triggered 'msg' timer broadcasts a 'message' event)
  my $id = $core->timer_set( 60,
    {
      ## The type of timer; 'msg', 'action' or 'event':
      Type => 'msg',

      ## This is a 'msg' timer; we need to know what to send
      ## 'action' carries the same syntax
      Context => $context,
      Target  => $channel,
      Text    => $string,
    }
  );

Here's the same timer, but using the pure object syntax:

  use Bot::Cobalt::Timer;
  $core->timer_set(
    Bot::Cobalt::Timer->new(
      core    => $core,
      context => $context,
      target  => $channel,
      text    => $string,
      type    => 'msg',
      delay   => 60
    );
  );

If no Type is specified, event is assumed:

  ## Trigger event $event in $secs with (optional) @args:
  my $id = $core->timer_set( $secs,
    {
      Event => $event,
      Args  => [ @args ],
    }
  );
  
  ## ... same thing, but object interface:
  my $id = $core->timer_set(
    Bot::Cobalt::Timer->new(
      core  => $core,
      event => $event,
      args  => \@args,
    );
  );

You can tags packages with your plugin's Alias, if you'd like; if an Alias is set, you'll be able to clear all timers by alias via "timer_del_alias" or retrieve them via "timer_get_alias":

  ## Alias-tagged timer
  my $id = $core->timer_set( $secs,
    {
      Event => $event,
      Args  => [ @args ],
      ## Safely retrieve our $self object's plugin alias:
      Alias => $core->get_plugin_alias( $self ),
    },
  );

(The Bot::Cobalt::Timer object interface uses the alias attribute.)

Additionally, Bot::Cobalt::Plugin::PluginMgr automatically tries to clear plugin timers for unloaded plugins; this only works for Alias-tagged timers. Without a specified Alias, a timer is essentially considered ownerless -- it will happily fire at their scheduled time even if the issuing plugin is gone.

By default, a random timer ID is chosen (and returned).

You can also specify an ID:

  ## Set a timer with specified ID 'MyTimer'
  ## Will overwrite any preexisting timers with the same ID
  $core->timer_set( 
    $secs,
    { Event => $event, Args => [ @args ] },
    'MyTimer'
  );

(The Bot::Cobalt::Timer object interface uses the id attribute.)

This can be used for resetting timers you've already set; grab the ID returned by a timer_set() call and reset it to change the event or delay.

You may want timestr_to_secs from Bot::Cobalt::Utils for easy conversion of human-readable strings into seconds. This is, of course, included by default if you use Bot::Cobalt::Common.

If you need better accuracy, you'll need to use your own alarm()/delay() calls to POE::Kernel; the timer pool is checked every second or so.

Arguments specified in the Args array reference or args object attribute will be relayed to plugin event handlers just like any other event's parameters:

  sub Bot_some_timed_event {
    ## Called by a timer_set() timer
    my ($self, $core) = splice @_, 0, 2;
    my $firstarg = ${ $_[0] };
    my $second   = ${ $_[1] };
  }

timer_del

Delete a timer by ID.

  my $deleted = $core->timer_del( $id );

Returns the deleted timer object, or nothing if there was no such ID.

The returned result (if there is one) can be fed back to "timer_set" if needed; it will be a Bot::Cobalt::Timer object:

  ## hang on to this timer for now:
   my $postponed = $core->timer_del( $id ) ;

  ## . . . situation changes . . .
   $postponed->delay(60);
  
   if ( $core->timer_set( $postponed ) ) {
     ## readding postponed timer successful
   }

timer_del_alias

Delete all timers owned by the specified alias:

  my $plugin_alias  = $core->plugin_get_alias( $self );
  my $deleted_count = $core->timer_del_alias( $plugin_alias );

Only works for timers tagged with their Alias; see "timer_set". Timers with no Alias tag are considered essentially "ownerless" and left to their own devices; they'll fail quietly if the timed event was handled by an unloaded plugin.

This is also called automatically by the core plugin manager (Bot::Cobalt::Plugin::PluginMgr) when a plugin is unloaded.

timer_get_alias

Find out which active timerIDs are owned by the specified alias:

  my $plugin_alias  = $core->plugin_get_alias( $self );
  my @active_timers = $core->timer_get_alias( $plugin_alias );

timer_get

Retrieve the Bot::Cobalt::Timer for this active timer (or undef if not found).

  my $this_timer = $core->timer_get($id);

Syndicated core events

These are events sent by Bot::Cobalt::Core when various core states change.

You should probably return PLUGIN_EAT_NONE on all of these, unless you are absolutely sure of what you are doing.

Plugin related events

Bot_plugins_initialized

Broadcast when the initial plugin load has completed at start-time.

Carries no arguments.

Bot_plugin_error

Broadcast when the syndicator reports an error from a plugin.

The only argument is the error string reported by POE::Component::Syndicator.

These messages are also logged to 'warn' by default.

Timer related events

Bot_executed_timer

Broadcast whenever a timer ID has been executed.

The only argument is the timer ID.

Bot_deleted_timer

Broadcast whenever a timer ID has been deleted.

The first argument is the timer ID.

The second argument is the removed Bot::Cobalt::Timer object.

Ignore related events

flood_ignore_added

Broadcast by Bot::Cobalt::IRC when a temporary anti-flood ignore has been placed.

Arguments are the server context name and the mask that was added, respectively.

flood_ignore_deleted

Broadcast by Bot::Cobalt::IRC when a temporary anti-flood ignore has expired and been removed.

Arguments are the same as "flood_ignore_added".

PLUGIN DESIGN TIPS ^

Useful tools

Bot::Cobalt

Importing Bot::Cobalt via 'use Bot::Cobalt' brings in the Bot::Cobalt::Core::Sugar functions.

These provide simple syntax sugar for accessing the Bot::Cobalt::Core singleton and common methods such as send_event; consult the Bot::Cobalt::Core::Sugar documentation for details.

Bot::Cobalt::Common

Bot::Cobalt::Common is a simple exporter that will pull in common constants and utilities from Object::Pluggable::Constants, IRC::Utils, and Bot::Cobalt::Utils.

Additionally, use Bot::Cobalt::Constant will enable the strict and warnings pragmas.

This is provided as a convenience for plugin authors; rather than importing from a goodly handful of modules, you can simply:

  use Bot::Cobalt::Common;

Declaring strict and warnings explicitly are still good practice.

See Bot::Cobalt::Common for details.

Bot::Cobalt::DB

Bot::Cobalt::DB provides an easy object-oriented interface to storing and retrieving Perl data structures to/from BerkeleyDB via DB_File.

Useful when a plugin has some persistent data it needs to keep track of, but storing it in memory and serializing to/from disk is too expensive.

  use Bot::Cobalt::DB;

  # new object for this db, creating it if it doesn't exist:
  $db = Bot::Cobalt::DB->new(
    File => $some_db_path,
  );

  # open and lock the db:
  $db->dbopen || return "database open failed!";

  # 'put' some data structure in the db:
  my $ref = { Some => [ 'Data', 'Structure' ] };
  $db->put('MyKey', $ref);
  
  # 'get' some other data structure:
  my $other_data = $db->get('OtherKey');
  
  # close/unlock db:
  $db->dbclose;

See Bot::Cobalt::DB for complete usage information.

Bot::Cobalt::Serializer

It is often useful to serialize arbitrary data structures to some standardized format. Serialization formats such as JSON and YAML are convenient for "speaking" to other networked applications, sharing data, or saving persistent data to disk in an easily-retrievable format.

Bot::Cobalt comes with a simple object oriented frontend to some common serialization formats, as well as built-in file operations for "freezing" and "thawing" data to/from files on disk:

  use Bot::Cobalt::Serializer;

  ## create a JSON serializer:
  my $jsify = Bot::Cobalt::Serializer->new( Format => 'JSON' );

  ## serialize a perl hash:
  my $ref = { Some => { Deep => [ 'Structure' ] } };
  my $json = $jsify->freeze($ref);

See Bot::Cobalt::Serializer.

Bot::Cobalt::Utils

Bot::Cobalt::Utils provides a functional-style interface to various tools useful in effective plugin authoring.

Tools include flexible (bcrypt-enabled) password hashing and comparison functions, string formatting with arbitrary variable replacement rules, Cobalt-style glob syntax tools, color/format interpolation, and others.

  ## Import all Bot::Cobalt::Utils funcs:
  use Bot::Cobalt::Utils qw/ :ALL /;

See Bot::Cobalt::Utils.

IRC::Utils

IRC::Utils is a very useful module covering many basic IRC-related tasks, such as host normalization / matching and casemapping-aware IRC uppercase/lowercase tools.

It is used extensively by both Bot::Cobalt and POE::Component::IRC and therefore guaranteed to be available for use.

See IRC::Utils for upstream's documentation.

Bot::Cobalt::Plugin::WWW

It's fairly common to want to make some kind of HTTP request from an IRC bot. The most common Perl method of speaking HTTP is LWP::UserAgent -- which will block the plugin pipeline until the request is complete.

Bot::Cobalt::Plugin::WWW, if loaded, dispatches HTTP requests asynchronously via POE::Component::Client::HTTP and returns HTTP::Response responses to the plugin pipeline:

  ## build a request object via HTTP::Request
  use HTTP::Request;

  ## a simple GET, see HTTP::Request docs for more info:
  my $request = HTTP::Request->new( 'GET', $url );

  ## push it to www_request with a response event:
  broadcast( 'www_request',
    $request,
    'myplugin_resp_recv',

     ## you can include a reference containing args
     ## (or a scalar, if you like)
     ##
     ## here's an example args arrayref telling our handler 
     ## where to send responses:
     [ $context, $channel, $nickname ],
  );
  
  ## handle a response when one is received:
  sub Bot_myplugin_resp_recv {
    my ($self, $core) = splice @_, 0, 2;

    ## if the request was successful, $_[0] is a ref to the 
    ## decoded content from HTTP::Response
    ## (otherwise, it is the HTTP status message)
    my $content  = ${ $_[0] };

    ## $_[1] is the HTTP::Response object, see perldoc HTTP::Response
    my $response = ${ $_[1] };

    ## $_[2] is whatever argument ref was provided in www_request
    my $argref   = ${ $_[2] };

    ## in our example above, it was some contextual info:
    my ($context, $channel, $nickname) = @$argref;

    if ($response->is_success) {
      ## . . . do something with the response . . .
    } else {
      ## request failed (see HTTP::Response)
    }
  
    ## eat this event, we're the only handler:
    return PLUGIN_EAT_ALL
  }

When a response is received, it will be pushed to the plugin pipeline as the specified SERVER event.

If the plugin is available, $core->Provided->{www_request} will be boolean true:

  my $request = HTTP::Request->new( . . . );
  if ($core->Provided->{www_request}) {
    ## send www_request event like above
    . . .   
  } else {
    ## no async available, error out or use LWP or something:
    my $ua = LWP::UserAgent->new(
      timeout => 5,
      max_redirect => 0,
    );
    my $response = $ua->request($request);
    my $content = $response->content;
  }

Retrieving $core

It may be necessary or convenient to use Bot::Cobalt::Core methods from outside of a syndicated event handler.

If your plugin imports Bot::Cobalt via 'use Bot::Cobalt', the core() function will retrieve the instanced Bot::Cobalt::Core; for example:

  core()->auth->level( . . . )

See Bot::Cobalt::Core::Sugar for details on functions exported when you 'use Bot::Cobalt'.

If you don't want to use the sugary functions and would rather make method calls directly, Bot::Cobalt::Core is an instanced singleton; loaded plugins can always retrieve the running Bot::Cobalt::Core via the instance method:

  sub my_routine {
    my ($self, @args) = @_;
    
    require Bot::Cobalt::Core;
    croak "No Core instance available"
      unless Bot::Cobalt::Core->has_instance;
    my $core = Bot::Cobalt::Core->instance;
  }

Non-reloadable plugins

By default, a plugin can be unloaded/reloaded at any time, typically via the Bot::Cobalt::Plugin::PluginMgr !plugin administrative interface.

If a plugin is marked as being unreloadable, plugin managers such as the included Bot::Cobalt::Plugin::PluginMgr will recognize it as such and refuse to unload or reload the plugin once it is loaded.

Declaring non-reloadable status

A plugin can declare itself as not being reloadable with a simple method returning boolean true:

sub NON_RELOADABLE { 1 }

ADVANCED CONCEPTS ^

Breaking up lengthy loops

Cobalt operates in an event loop -- implying that any piece of code that blocks for any significant length of time is holding up the rest of the loop:

  sub Bot_some_event {
    my ($self, $core) = splice @_, 0, 2;
    
    my @items = long_list_of_items();
    
    BIGLOOP: for my $item (@items) {
      do_work_on($item);
    }
    ## everything else stops until BIGLOOP is done
  }

Instead, you can break the loop into event handlers and yield back to the event loop, cooperatively multitasking with other events.

The below example processes a large list of items, pushing remaining items back to the 'worker' event handler after iterating 100 items.

  sub Cobalt_register {
    ## ... initialization...
    ## ... register for myplugin_start_work, myplugin_do_work
  }

  ## Some event that starts a long-running loop:
  sub Bot_myplugin_start_work {
    my ($self, $core) = splice @_, 0, 2;
    
    my @items = long_list_of_items();
        
     ## begin _do_work
     ## pass our @items to it, for example:
    $core->send_event( 'myplugin_do_work', [ @items ] );
    
    return PLUGIN_EAT_ALL   
  }
  
  sub Bot_myplugin_do_work {
    my ($self, $core) = splice @_, 0, 2;
    
     ## our remaining items:
    my $itemref = ${ $_[0] };
    my @items = @$itemref;
    
     ## maximum number of elements to process before yield:
    my $max_this_run = 100;
    while (@items && --$max_this_run != 0) {
      my $item = shift @items;
      ## ... do some work on $item ...
    }

     ## if there's any items left, push them and yield:
    if (@items) {
      $core->send_event( 'myplugin_do_work', [ @items ] );
    } else {
      ## no items left, we are finished
      ## tell pipeline we're done, perhaps:
      $core->send_event( 'myplugin_finished_work' );
    }

    return PLUGIN_EAT_ALL
  }

For more fine-grained control, consider running your own POE::Session; see "Spawning your own POE::Session", below.

Spawning your own POE::Session

There's nothing preventing you from spawning your own POE::Session; your session will run within Cobalt's POE::Kernel instance and POE event handlers will work as-normal.

Motivations for doing so include fine-grained timer control, integration with POE bits such as the POE::Component and POE::Wheel namespaces . . . and the fact that POE is pretty great ;-)

It's worth noting that many POE Components use get_active_session to determine where to send responses. It may sometimes be necessary to use intermediary "proxy" methods to ensure a proper destination session is set in the POE::Component in use. See Bot::Cobalt::Plugin::WWW source for an example of a plugin that uses its own POE::Session and does this (when issuing HTTP requests to POE::Component::Client::HTTP).

Manipulating plugin pipeline order

Object::Pluggable allows you to manipulate the plugin pipeline order; that is to say, the order in which events will hit plugins.

For example, when writing a plugin such as an input filter, it can be useful to move your plugin towards the top of the plugin pipeline:

  ## With 'use Bot::Cobalt':
  core->pipeline->bump_up( plugin_alias($self) );

See Object::Pluggable::Pipeline for details.

Plugin managers are not required to take any special consideration of a plugin's previous position in the case of a plugin (re)load.

IRC CAVEATS ^

IRC casemapping rules

Determining whether or not nicknames and channels are equivalent on IRC is not as easy as it looks.

Per the RFC (http://tools.ietf.org/html/rfc1459#section-2.2):

  the characters {}| are
  considered to be the lower case equivalents of the characters []\,
  respectively

This set ( {}| == []\ ) is called strict-rfc1459 and identified as such in a server's ISUPPORT CASEMAPPING= directive.

More often, servers use the set commonly identified as rfc1459:

  ## rfc1459 lower->upper case change: {}|^ == []\~
  $value =~ tr/a-z{}|^/A-Z[]\\~/;

Some servers may use normal ASCII case rules; they will typically announce ascii in CASEMAPPING=.

Bot::Cobalt::IRC will attempt to determine and save a server's CASEMAPPING value at connect time. Some broken server configurations announce junk in CASEMAPPING and their actual valid casemapping ruleset in CHARSET; Bot::Cobalt::IRC will fall back to CHARSET if CHARSET is a valid casemap but CASEMAPPING is invalid. If all else fails, rfc1459 is used.

The saved value can be used to feed eq_irc and friends from IRC::Utils and determine nickname/channel equivalency.

See "get_irc_casemap" and IRC::Utils

Character encodings

IRC doesn't come with a lot of guarantees regarding character encodings.

Hopefully, you are getting either CP1252 or UTF-8.

The IRC::Utils POD contains an excellent discussion of the general problem; see "ENCODING" in IRC::Utils.

"decode_irc" in IRC::Utils is included if you 'use Bot::Cobalt::Common'.

SEE ALSO ^

Bot:Cobalt::IRC covers events handled and emitted by the IRC plugin.

Bot::Cobalt::Manual::Plugins::Tutorial contains a simple walk-through tutorial on plugin writing.

Bot::Cobalt::Manual::Plugins::Config describes configuration files used by plugins.

Bot::Cobalt::Manual::Plugins::Dist covers packaging your module for installation.

Bot::Cobalt::Core::Sugar describes functional sugar imported when you use Bot::Cobalt;.

Plugin authors may also be interested in using Bot::Cobalt::Utils.

You can view the full documentation at http://www.metacpan.org/release/Bot-Cobalt.

Relevant CPAN documentation

Bot::Cobalt::Core and Bot::Cobalt::IRC are mostly a lot of sugar over the following very useful CPAN modules:

AUTHOR ^

Jon Portnoy <avenj@cobaltirc.org>

http://www.cobaltirc.org

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