IO::Async::Protocol::Stream

Section: User Contributed Perl Documentation (3pm)
Updated: 2018-04-19
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NAME

"IO::Async::Protocol::Stream" - base class for stream-based protocols

SYNOPSIS

Most likely this class will be subclassed to implement a particular network protocol.

 package Net::Async::HelloWorld;

 use strict;
 use warnings;
 use base qw( IO::Async::Protocol::Stream );

 sub on_read
 {
    my $self = shift;
    my ( $buffref, $eof ) = @_;

    return 0 unless $$buffref =~ s/^(.*)\n//;
    my $line = $1;

    if( $line =~ m/^HELLO (.*)/ ) {
       my $name = $1;

       $self->invoke_event( on_hello => $name );
    }

    return 1;
 }

 sub send_hello
 {
    my $self = shift;
    my ( $name ) = @_;

    $self->write( "HELLO $name\n" );
 }

This small example elides such details as error handling, which a real protocol implementation would be likely to contain.

DESCRIPTION

This subclass of IO::Async::Protocol is intended to stand as a base class for implementing stream-based protocols. It provides an interface similar to IO::Async::Stream, primarily, a "write" method and an "on_read" event handler.

It contains an instance of an IO::Async::Stream object which it uses for actual communication, rather than being a subclass of it, allowing a level of independence from the actual stream being used. For example, the stream may actually be an IO::Async::SSLStream to allow the protocol to be used over SSL.

As with IO::Async::Stream, it is required that by the time the protocol object is added to a Loop, that it either has an "on_read" method, or has been configured with an "on_read" callback handler.

EVENTS

The following events are invoked, either using subclass methods or CODE references in parameters:

$ret = on_read \$buffer, $eof

on_read_eof

on_write_eof

The event handlers are invoked identically to IO::Async::Stream.

on_closed

The "on_closed" handler is optional, but if provided, will be invoked after the stream is closed by either side (either because the "close()" method has been invoked on it, or on an incoming EOF).

PARAMETERS

The following named parameters may be passed to "new" or "configure":

on_read => CODE

on_read_eof => CODE

on_write_eof => CODE

CODE references for the events.

handle => IO

A shortcut for the common case where the transport only needs to be a plain IO::Async::Stream object. If this argument is provided without a "transport" object, a new IO::Async::Stream object will be built around the given IO handle, and used as the transport.

METHODS

write

   $protocol->write( $data )

Writes the given data by calling the "write" method on the contained transport stream.

connect

   $protocol->connect( %args )

Sets up a connection to a peer, and configures the underlying "transport" for the Protocol. Calls IO::Async::Protocol "connect" with "socktype" set to "stream".

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>