Mojo::Reactor

Section: User Contributed Perl Documentation (3)
Updated: 2018-11-22
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NAME

Mojo::Reactor - Low-level event reactor base class

SYNOPSIS

  package Mojo::Reactor::MyEventLoop;
  use Mojo::Base 'Mojo::Reactor';

  sub again      {...}
  sub io         {...}
  sub is_running {...}
  sub next_tick  {...}
  sub one_tick   {...}
  sub recurring  {...}
  sub remove     {...}
  sub reset      {...}
  sub start      {...}
  sub stop       {...}
  sub timer      {...}
  sub watch      {...}

DESCRIPTION

Mojo::Reactor is an abstract base class for low-level event reactors, like Mojo::Reactor::EV and Mojo::Reactor::Poll.

EVENTS

Mojo::Reactor inherits all events from Mojo::EventEmitter and can emit the following new ones.

error

  $reactor->on(error => sub {
    my ($reactor, $err) = @_;
    ...
  });

Emitted for exceptions caught in callbacks, fatal if unhandled. Note that if this event is unhandled or fails it might kill your program, so you need to be careful.

  $reactor->on(error => sub {
    my ($reactor, $err) = @_;
    say "Something very bad happened: $err";
  });

METHODS

Mojo::Reactor inherits all methods from Mojo::EventEmitter and implements the following new ones.

again

  $reactor->again($id);

Restart timer. Meant to be overloaded in a subclass. Note that this method requires an active timer.

detect

  my $class = Mojo::Reactor->detect;

Detect and load the best reactor implementation available, will try the value of the "MOJO_REACTOR" environment variable, Mojo::Reactor::EV or Mojo::Reactor::Poll.

  # Instantiate best reactor implementation available
  my $reactor = Mojo::Reactor->detect->new;

io

  $reactor = $reactor->io($handle => sub {...});

Watch handle for I/O events, invoking the callback whenever handle becomes readable or writable. Meant to be overloaded in a subclass.

  # Callback will be executed twice if handle becomes readable and writable
  $reactor->io($handle => sub {
    my ($reactor, $writable) = @_;
    say $writable ? 'Handle is writable' : 'Handle is readable';
  });

is_running

  my $bool = $reactor->is_running;

Check if reactor is running. Meant to be overloaded in a subclass.

next_tick

  my $undef = $reactor->next_tick(sub {...});

Execute callback as soon as possible, but not before returning or other callbacks that have been registered with this method, always returns "undef". Meant to be overloaded in a subclass.

one_tick

  $reactor->one_tick;

Run reactor until an event occurs. Note that this method can recurse back into the reactor, so you need to be careful. Meant to be overloaded in a subclass.

  # Don't block longer than 0.5 seconds
  my $id = $reactor->timer(0.5 => sub {});
  $reactor->one_tick;
  $reactor->remove($id);

recurring

  my $id = $reactor->recurring(0.25 => sub {...});

Create a new recurring timer, invoking the callback repeatedly after a given amount of time in seconds. Meant to be overloaded in a subclass.

remove

  my $bool = $reactor->remove($handle);
  my $bool = $reactor->remove($id);

Remove handle or timer. Meant to be overloaded in a subclass.

reset

  $reactor->reset;

Remove all handles and timers. Meant to be overloaded in a subclass.

start

  $reactor->start;

Start watching for I/O and timer events, this will block until ``stop'' is called. Note that some reactors stop automatically if there are no events being watched anymore. Meant to be overloaded in a subclass.

  # Start reactor only if it is not running already
  $reactor->start unless $reactor->is_running;

stop

  $reactor->stop;

Stop watching for I/O and timer events. Meant to be overloaded in a subclass.

timer

  my $id = $reactor->timer(0.5 => sub {...});

Create a new timer, invoking the callback after a given amount of time in seconds. Meant to be overloaded in a subclass.

watch

  $reactor = $reactor->watch($handle, $readable, $writable);

Change I/O events to watch handle for with true and false values. Meant to be overloaded in a subclass. Note that this method requires an active I/O watcher.

  # Watch only for readable events
  $reactor->watch($handle, 1, 0);

  # Watch only for writable events
  $reactor->watch($handle, 0, 1);

  # Watch for readable and writable events
  $reactor->watch($handle, 1, 1);

  # Pause watching for events
  $reactor->watch($handle, 0, 0);