NAME

Mojo::IOLoop - Minimalistic Event Loop For TCP Clients And Servers

SYNOPSIS

    use Mojo::IOLoop;

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

    # Listen on port 3000
    $loop->listen(
        port => 3000,
        cb   => sub {
            my ($self, $id) = @_;

            # Start read only when accepting a new connection
            $self->not_writing($id);

            # Incoming data
            $self->read_cb($id => sub {
                my ($self, $id, $chunk) = @_;

                # Got some data, time to write
                $self->writing($id);
            });

            # Ready to write
            $self->write_cb($id => sub {
                my ($self, $id) = @_;

                # Back to reading only
                $self->not_writing($id);

                # The loop will take care of buffering for us
                return 'HTTP/1.1 200 OK';
            });
        }
    );

    # Connect to port 3000 with TLS activated
    my $id = $loop->connect(address => 'localhost', port => 3000, tls => 1);

    # Loop starts writing
    $loop->writing($id);

    # Writing request
    $loop->write_cb($id => sub {
        my ($self, $id) = @_;

        # Back to reading only
        $self->not_writing($id);

        # The loop will take care of buffering for us
        return "GET / HTTP/1.1\r\n\r\n";
    });

    # Reading response
    $loop->read_cb($id => sub {
        my ($self, $id, $chunk) = @_;

        # Time to write more
        $self->writing($id);
    });

    # Add a timer
    $loop->timer($id => (after => 5, cb => sub {
        my ($self, $cid, $tid) = @_;
        $self->drop($cid);
    }));

    # Add another timer
    $loop->timer($id => (interval => 3, cb => sub {
        print "Timer is running again!\n";
    }));

    # Start and stop loop
    $loop->start;
    $loop->stop;

DESCRIPTION

Mojo::IOLoop is a very minimalistic event loop that has been reduced to the absolute minimal feature set required to build solid and scalable TCP clients and servers, easy to extend and replace with alternative implementations.

Optional modules IO::KQueue, IO::Epoll, IO::Socket::INET6 and IO::Socket::SSL are supported transparently and used if installed.

ATTRIBUTES

Mojo::IOLoop implements the following attributes.

accept_timeout

    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 5.

connect_timeout

    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 5.

lock_cb

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

A locking callback that decides if this loop is allowed to listen for new incoming connections, used to sync multiple server processes. The callback should return true or false.

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

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

max_connections

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

The maximum number of 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.

unlock_cb

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

A callback to free the listen lock, called after accepting a new connection and used to sync multiple server processes.

timeout

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

Maximum time in seconds our loop waits for new events to happen, defaults to 0.25.

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 = $loop->connect(
        address => '127.0.0.1',
        port    => 3000,
        cb      => sub {...}
    );
    my $id = $loop->connect({
        address => '127.0.0.1',
        port    => 3000,
        cb      => sub {...}
    });
    my $id = $loop->connect({
        address => '[::1]',
        port    => 443,
        tls     => 1,
        cb      => sub {...}
    });

Open a TCP connection to a remote host, IPv6 will be used automatically if available. Note that IPv6 support depends on IO::Socket::INET6 and TLS support on IO::Socket::SSL.

These options are currently available.

address

Address or host name of the peer to connect to.

cb

Callback to be invoked once the connection is established.

port

Port to connect to.

tls

Enable TLS.

tls_ca_file

CA file to use for TLS.

tls_verify_cb

Callback to invoke for TLS verification.

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.

drop

    $loop = $loop->drop($id);

Drop a connection, listen socket or timer. Connections will be dropped gracefully by allowing them to finish writing all data in it's write buffer.

error_cb

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

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

generate_port

    my $port = $loop->generate_port;

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

hup_cb

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

Callback to be invoked if the connection gets closed.

listen

    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, IPv6 will be used automatically if available. Note that IPv6 support depends on IO::Socket::INET6 and TLS support on IO::Socket::SSL.

These options are currently available.

address

Local address to listen on, defaults to all.

cb

Callback to invoke for each accepted connection.

file

A unix domain socket to listen on.

port

Port to listen on.

queue_size

Maximum queue size, defaults to SOMAXCONN.

tls

Enable TLS.

tls_cert

Path to the TLS cert file.

tls_key

Path to the TLS key file.

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.

not_writing

    $loop->not_writing($id);

Activate read only mode for a connection. Note that connections have no mode after they are created.

read_cb

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

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

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

        # Process chunk
    });

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.

start

    $loop->start;

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

stop

    $loop->stop;

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

timer

    my $id = $loop->timer($id => (after => 5, cb => sub {...}));
    my $id = $loop->timer($id => {interval => 5, cb => sub {...}}));

Create a new timer, invoking the callback afer a given amount of seconds. Note that timers are bound to connections and will get destroyed together with them.

These options are currently available.

after

Start timer after this exact amount of seconds.

cb

Callback to invoke.

interval

Interval in seconds to run timer recurringly.

write_cb

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

Callback to be invoked if new data can be written to the connection. The callback should return a chunk of data which will be buffered inside the loop to guarantee safe writing.

    $loop->write_ab($id => sub {
        my ($loop, $id) = @_;
        return 'Data to be buffered by the loop!';
    });

writing

    $loop->writing($id);

Activate read/write mode for a connection. Note that connections have no mode after they are created.

SEE ALSO

Mojolicious, Mojolicious::Book, http://mojolicious.org.