Security Advisories (2)
CVE-2024-58134 (2025-05-03)

Mojolicious versions from 0.999922 for Perl uses a hard coded string, or the application's class name, as a HMAC session secret by default. These predictable default secrets can be exploited to forge session cookies. An attacker who knows or guesses the secret could compute valid HMAC signatures for the session cookie, allowing them to tamper with or hijack another user's session.

CVE-2024-58135 (2025-05-03)

Mojolicious versions from 7.28 for Perl may generate weak HMAC session secrets. When creating a default app with the "mojo generate app" tool, a weak secret is written to the application's configuration file using the insecure rand() function, and used for authenticating and protecting the integrity of the application's sessions. This may allow an attacker to brute force the application's session keys.

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

$reactor->on(error => sub ($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.

$reactor->on(error => sub ($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);
$reactor->again($id, 0.5);

Restart timer and optionally change the invocation time. 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 ($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);

SEE ALSO

Mojolicious, Mojolicious::Guides, https://mojolicious.org.