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

  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;

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 IO::KQueue, IO::Epoll, 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.

Mojo::IOLoop implements the following attributes.

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

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

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

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

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

Maximum time in seconds a DNS lookup can take, defaults to 3. Note that this attribute is EXPERIMENTAL and might change without warning!

  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!

  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.

  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;
  });

  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.

  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.

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

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

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

  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 event happens on the connection.

on_read

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

port

Port to connect to.

proto

Protocol to use, defaults to tcp.

tls

Enable TLS.

tls_cert

Path to the TLS certificate file.

tls_key

Path to the TLS key file.

  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.

  my @all     = Mojo::IOLoop->dns_servers;
  my @all     = $loop->dns_servers;
  my $current = $loop->dns_servers;
  $loop       = $loop->dns_servers('8.8.8.8', '8.8.4.4');

IP addresses of DNS servers used for non-blocking lookups, defaults to the value of MOJO_DNS_SERVER, auto detection, 8.8.8.8 or 8.8.4.4. Note that this method is EXPERIMENTAL and might change without warning!

  $loop = Mojo::IOLoop->drop($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.

  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.

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

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

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

Callback to be invoked on every reactor tick if no other events occurred. Note that this method is EXPERIMENTAL and might change without warning!

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

Check if loop is running.

  exit unless Mojo::IOLoop->is_running;

  my $id = Mojo::IOLoop->listen(port => 3000);
  my $id = $loop->listen(port => 3000);
  my $id = $loop->listen({port => 3000});
  my $id = $loop->listen(file => '/foo/myapp.sock');
  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.

file

A unix domain socket to listen on.

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 event 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.

  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.

  $loop = Mojo::IOLoop->lookup('mojolicio.us' => sub {...});
  $loop = $loop->lookup('mojolicio.us' => sub {...});

Lookup IPv4 or IPv6 address for domain. Note that this method is EXPERIMENTAL and might change without warning!

  $loop->lookup('mojolicio.us' => sub {
    my ($loop, $address) = @_;
    print "Address: $address\n";
  });

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

Callback to be invoked if the connection gets closed.

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

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

  $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
  });

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

Run reactor for exactly one tick.

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

Callback to be invoked on every reactor tick, 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.

  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.

  $loop = Mojo::IOLoop->resolve('mojolicio.us', 'A', sub {...});
  $loop = $loop->resolve('mojolicio.us', 'A', sub {...});

Resolve domain into A, AAAA, CNAME, MX, NS, PTR or TXT records, * will query for all at once. Since this is a "stub resolver" it depends on a recursive name server for DNS resolution. Note that this method is EXPERIMENTAL and might change without warning!

  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;

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

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

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

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

  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.

  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!

  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.

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

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

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

  MOJO_IOLOOP_DEBUG=1

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