NAME

POE::Component::DirWatch - POE directory watcher

SYNOPSIS

  use POE::Component::DirWatch;

  my $watcher = POE::Component::DirWatch->new
    (
     alias      => 'dirwatch',
     directory  => '/some_dir',
     filter     => sub { $_[0]->is_file ? $_[0] =~ /\.gz$/ : 1 },
     dir_callback  => sub{ ... },
     file_callback => sub{ ... },
     interval   => 1,
    );

  $poe_kernel->run;

DESCRIPTION

POE::Component::DirWatch watches a directory for files or directories. Upon finding either it will invoke a user-supplied callback function depending on whether the item is a file or directory.

ASYNCHRONOUS IO SUPPORT

This object supports asynchronous IO access using IO::AIO. At load time, the class will detect whether IO::AIO is present in the host system and, if it is present, apply the POE::Component::DirWatch::Role::AIO role to the current class, adding the "aio" attribute, the <aio_callback> event, and replacing "_poll" with an asynchronous version. If you do not wish to use AIO you can specify so with he "no_aio" flag like this:

    use POE::Component::DirWatch (no_aio => 1);

ATTRIBUTES

alias

Read only alias for the DirWatch session. Defaults to "dirwatch" if not specified. You can NOT rename a session at runtime.

interval

Required read-write integer representing interval between the end of a poll event and the scheduled start of the next. Defaults to 1.

file_callback

has_file_callback - predicate
clear_file_callback - clearer

Optional read-write code reference to call when a file is found. The code reference will passed a single argument, a Path::Class::File object representing the file found. It usually makes most sense to process the file and remove it from the directory to avoid duplicate processing

dir_callback

has_dir_callback - predicate
clear_dir_callback - clearer

Optional read-write code reference to call when a directory is found. The code reference will passed a single argument, a Path::Class::Dir object representing the directory found.

filter

has_filter - predicate
clear_filter - clearer

An optional read-write code reference that, if present, will be called for each item in the watched directory. The code reference will passed a single argument, a Path::Class::File or Path::Class::Dir object representing the file/dir found. The code should return true if the callback should be called and false if the file should be ignored.

next_poll

has_next_poll - predicate
clear_next_poll - clearer

The ID of the alarm for the next scheduled poll, if any. Has clearer and predicate methods named "clear_next_poll" and "has_next_poll". Please note that clearing the "next_poll" just clears the next poll id, it does not remove the alarm, please use "pause" for that.

OBJECT METHODS

new( \%attrs)

  See SYNOPSIS and ATTRIBUTES.

session

Returns a reference to the actual POE session. Please avoid this unless you are subclassing. Even then it is recommended that it is always used as "$watcher->session->method" because copying the object reference around could create a problem with lingering references.

pause [$until]

Synchronous call to _pause. This just posts an immediate _pause event to the kernel.

resume [$when]

Synchronous call to _resume. This just posts an immediate _resume event to the kernel.

shutdown

Convenience method that posts a FIFO shutdown event.

EVENT HANDLING METHODS

These methods are not part of the public interface of this class, and expect to be called from whithin POE with the standard positional arguments. Use them at your own risk.

_start

Runs when "$poe_kernel->run" is called to set the session's alias and schedule the first "poll" event.

_poll

Triggered by the "poll" event this is the re-occurring action. _poll will use get a list of all items in the directory and call the appropriate callback.

_file_callback

Will execute the "file_callback" code reference, if any.

_pause [$until]

Triggered by the "_pause" event this method will remove the alarm scheduling the next directory poll. It takes an optional argument of $until, which dictates when the polling should begin again. If $until is an integer smaller than the result of time() it will treat $until as the number of seconds to wait before polling. If $until is an integer larger than the result of time() it will treat $until as an epoch timestamp.

     #these two are the same thing
     $watcher->pause( time() + 60);
     $watcher->pause( 60 );

     #this is one also the same
     $watcher->pause;
     $watcher->resume( 60 );

_resume [$when]

Triggered by the "_resume" event this method will remove the alarm scheduling the next directory poll (if any) and schedule a new poll alarm. It takes an optional argument of $when, which dictates when the polling should begin again. If $when is an integer smaller than the result of time() it will treat $until as the number of seconds to wait before polling. If $until is an integer larger than the result of time() it will treat $when as an epoch timestamp and schedule the poll alarm accordingly. If not specified, the alarm will be scheduled with a delay of zero.

_shutdown

Delete the "heap", remove the alias we are using and remove all set alarms.

BUILD

Constructor. "create()"s a POE::Session.

TODO

More examples
More tests
ChangeNotify support (patches welcome!)

AUTHOR

Guillermo Roditi, <groditi@cpan.org>

BUGS

Please report any bugs or feature requests to "bug-poe-component-dirwatch at rt.cpan.org", or through the web interface at <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=POE-Component-DirWatch>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

ACKNOWLEDGEMENTS

#poe & #moose on irc.perl.org
Matt S Trout
Rocco Caputo
Charles Reiss
Stevan Little
Eric Cholet