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/ Mojo::IOLoop

NAME

Mojo::IOLoop - Minimalistic Reactor For Async TCP Clients And Servers

SYNOPSIS

use Mojo::IOLoop;

# Listen on port 3000
Mojo::IOLoop->listen(
  port => 3000,
  on_read => sub {
    my ($self, $id, $chunk) = @_;

    # Process input
    print $chunk;

    # Got some data, time to write
    $self->write($id, 'HTTP/1.1 200 OK');
  }
);

# Connect to port 3000 with TLS activated
my $id = Mojo::IOLoop->connect(
  address => 'localhost',
  port => 3000,
  tls => 1,
  on_connect => sub {
    my ($self, $id) = @_;

    # Write request
    $self->write($id, "GET / HTTP/1.1\r\n\r\n");
  },
  on_read => sub {
    my ($self, $id, $chunk) = @_;

    # Process input
    print $chunk;
  }
);

# Add a timer
Mojo::IOLoop->timer(5 => sub {
  my $self = shift;
  $self->drop($id);
});

# Start and stop loop
Mojo::IOLoop->start;
Mojo::IOLoop->stop;

DESCRIPTION

Mojo::IOLoop is a very minimalistic reactor that has been reduced to the absolute minimal feature set required to build solid and scalable async TCP clients and servers.

Optional modules EV, IO::Socket::IP and IO::Socket::SSL are supported transparently and used if installed.

A TLS certificate and key are also built right in to make writing test servers as easy as possible.

ATTRIBUTES

Mojo::IOLoop implements the following attributes.

client_class

my $class = $loop->client_class;
$loop     = $loop->client_class('Mojo::IOLoop::Client');

Class to be used for performing non-blocking socket connections with the connect method, defaults to Mojo::IOLoop::Client. Note that this attribute is EXPERIMENTAL and might change without warning!

connect_timeout

my $timeout = $loop->connect_timeout;
$loop       = $loop->connect_timeout(5);

Maximum time in seconds a connection can take to be connected before being dropped, defaults to 3.

iowatcher

my $watcher = $loop->iowatcher;
$loop       = $loop->iowatcher(Mojo::IOWatcher->new);

Low level event watcher, usually a Mojo::IOWatcher or Mojo::IOWatcher::EV object. Replacing the event watcher of the singleton loop makes all new loops use the same type of event watcher. Note that this attribute is EXPERIMENTAL and might change without warning!

Mojo::IOLoop->singleton->iowatcher(MyWatcher->new);

max_accepts

my $max = $loop->max_accepts;
$loop   = $loop->max_accepts(1000);

The maximum number of connections this loop is allowed to accept before shutting down gracefully without interrupting existing connections, defaults to 0. Setting the value to 0 will allow this loop to accept new connections infinitely. Note that this attribute is EXPERIMENTAL and might change without warning!

max_connections

my $max = $loop->max_connections;
$loop   = $loop->max_connections(1000);

The maximum number of parallel connections this loop is allowed to handle before stopping to accept new incoming connections, defaults to 1000. Setting the value to 0 will make this loop stop accepting new connections and allow it to shutdown gracefully without interrupting existing connections.

on_lock

my $cb = $loop->on_lock;
$loop  = $loop->on_lock(sub {...});

A locking callback that decides if this loop is allowed to accept new incoming connections, used to sync multiple server processes. The callback should return true or false. Note that exceptions in this callback are not captured.

$loop->on_lock(sub {
  my ($loop, $blocking) = @_;

  # Got the lock, listen for new connections
  return 1;
});

on_unlock

my $cb = $loop->on_unlock;
$loop  = $loop->on_unlock(sub {...});

A callback to free the accept lock, used to sync multiple server processes. Note that exceptions in this callback are not captured.

resolver

my $resolver = $loop->resolver;
$loop        = $loop->resolver(Mojo::IOLoop::Resolver->new);

DNS stub resolver, usually a Mojo::IOLoop::Resolver object. Note that this attribute is EXPERIMENTAL and might change without warning!

server_class

my $class = $loop->server_class;
$loop     = $loop->server_class('Mojo::IOLoop::Server');

Class to be used for accepting incoming connections with the listen method, defaults to Mojo::IOLoop::Server. Note that this attribute is EXPERIMENTAL and might change without warning!

stream_class

my $class = $loop->stream_class;
$loop     = $loop->stream_class('Mojo::IOLoop::Stream');

Class to be used for streaming handles, defaults to Mojo::IOLoop::Stream. Note that this attribute is EXPERIMENTAL and might change without warning!

timeout

my $timeout = $loop->timeout;
$loop       = $loop->timeout(5);

Maximum time in seconds our loop waits for new events to happen, defaults to 0.025. Note that a value of 0 would make the loop non-blocking.

METHODS

Mojo::IOLoop inherits all methods from Mojo::Base and implements the following new ones.

new

my $loop = Mojo::IOLoop->new;

Construct a new Mojo::IOLoop object. Multiple of these will block each other, so use singleton instead if possible.

connect

my $id = Mojo::IOLoop->connect(
  address => '127.0.0.1',
  port    => 3000
);
my $id = $loop->connect(
  address => '127.0.0.1',
  port    => 3000
);

Open a TCP connection to a remote host. Note that TLS support depends on IO::Socket::SSL and IPv6 support on IO::Socket::IP.

These options are currently available:

address

Address or host name of the peer to connect to.

handle

Use an already prepared handle.

on_connect

Callback to be invoked once the connection is established.

on_close

Callback to be invoked if the connection gets closed.

on_error

Callback to be invoked if an error happens on the connection.

on_read

Callback to be invoked if new data arrives on the connection.

port

Port to connect to.

tls

Enable TLS.

tls_cert

Path to the TLS certificate file.

tls_key

Path to the TLS key file.

connection_timeout

my $timeout = $loop->connection_timeout($id);
$loop       = $loop->connection_timeout($id => 45);

Maximum amount of time in seconds a connection can be inactive before being dropped, defaults to 15.

drop

$loop = Mojo::IOLoop->drop($id)
$loop = $loop->drop($id);

Drop anything with an id. Connections will be dropped gracefully by allowing them to finish writing all data in its write buffer.

generate_port

my $port = Mojo::IOLoop->generate_port;
my $port = $loop->generate_port;

Find a free TCP port, this is a utility function primarily used for tests.

handle

my $handle = $loop->handle($id);

Get handle for id. Note that this method is EXPERIMENTAL and might change without warning!

is_running

my $running = Mojo::IOLoop->is_running;
my $running = $loop->is_running;

Check if loop is running.

exit unless Mojo::IOLoop->is_running;

listen

my $id = Mojo::IOLoop->listen(port => 3000);
my $id = $loop->listen(port => 3000);
my $id = $loop->listen({port => 3000});
my $id = $loop->listen(
  port     => 443,
  tls      => 1,
  tls_cert => '/foo/server.cert',
  tls_key  => '/foo/server.key'
);

Create a new listen socket. Note that TLS support depends on IO::Socket::SSL and IPv6 support on IO::Socket::IP.

These options are currently available:

address

Local address to listen on, defaults to all.

backlog

Maximum backlog size, defaults to SOMAXCONN.

on_accept

Callback to be invoked for each accepted connection.

on_close

Callback to be invoked if the connection gets closed.

on_error

Callback to be invoked if an error happens on the connection.

on_read

Callback to be invoked if new data arrives on the connection.

port

Port to listen on.

tls

Enable TLS.

tls_cert

Path to the TLS cert file, defaulting to a built-in test certificate.

tls_key

Path to the TLS key file, defaulting to a built-in test key.

tls_ca

Path to TLS certificate authority file or directory.

local_info

my $info = $loop->local_info($id);

Get local information about a connection.

my $address = $info->{address};

These values are to be expected in the returned hash reference.

address

The local address.

port

The local port.

on_close

$loop = $loop->on_close($id => sub {...});

Callback to be invoked if the connection gets closed.

on_error

$loop = $loop->on_error($id => sub {...});

Callback to be invoked if an error happens on the connection.

on_read

$loop = $loop->on_read($id => sub {...});

Callback to be invoked if new data arrives on the connection.

$loop->on_read($id => sub {
  my ($loop, $id, $chunk) = @_;

  # Process chunk
});

one_tick

$loop->one_tick;
$loop->one_tick('0.25');
$loop->one_tick(0);

Run reactor for exactly one tick.

recurring

my $id = Mojo::IOLoop->recurring(0 => sub {...});
my $id = $loop->recurring(3 => sub {...});

Create a new recurring timer, invoking the callback repeatedly after a given amount of seconds. This for example allows you to run multiple reactors next to each other.

my $loop2 = Mojo::IOLoop->new(timeout => 0);
Mojo::IOLoop->recurring(0 => sub { $loop2->one_tick });

Note that the loop timeout can be changed dynamically at any time to adjust responsiveness.

remote_info

my $info = $loop->remote_info($id);

Get remote information about a connection.

my $address = $info->{address};

These values are to be expected in the returned hash reference.

address

The remote address.

port

The remote port.

singleton

my $loop = Mojo::IOLoop->singleton;

The global loop object, used to access a single shared loop instance from everywhere inside the process. Many methods also allow you to take shortcuts when using the Mojo::IOLoop singleton.

Mojo::IOLoop->timer(2 => sub { Mojo::IOLoop->stop });
Mojo::IOLoop->start;

start

Mojo::IOLoop->start;
$loop->start;

Start the loop, this will block until stop is called or return immediately if the loop is already running.

start_tls

$loop->start_tls($id);

Start new TLS connection inside old connection. Note that TLS support depends on IO::Socket::SSL.

stop

Mojo::IOLoop->stop;
$loop->stop;

Stop the loop immediately, this will not interrupt any existing connections and the loop can be restarted by running start again.

test

my $success = $loop->test($id);

Test for errors and garbage bytes on the connection. Note that this method is EXPERIMENTAL and might change without warning!

timer

my $id = Mojo::IOLoop->timer(5 => sub {...});
my $id = $loop->timer(5 => sub {...});
my $id = $loop->timer(0.25 => sub {...});

Create a new timer, invoking the callback after a given amount of seconds.

write

$loop->write($id => 'Hello!');
$loop->write($id => 'Hello!', sub {...});

Write data to connection, the optional drain callback will be invoked once all data has been written.

DEBUGGING

You can set the MOJO_IOLOOP_DEBUG environment variable to get some advanced diagnostics information printed to STDERR.

MOJO_IOLOOP_DEBUG=1

SEE ALSO

Mojolicious, Mojolicious::Guides, http://mojolicio.us.