http://www.perlmonks.org?node_id=1065066


in reply to perl client for Socket.io

The old way to do a bi-directional socket, and usually the most foolproof, is to use a forking model. One fork watches for input fron STDIN to send, and the other fork receives from the socket. Try it.
#!/usr/bin/perl -w use strict; use IO::Socket; my ( $host, $port, $kidpid, $handle, $line ); #unless ( @ARGV == 2 ) { die "usage: $0 host port" } ( $host, $port ) = @ARGV || ('localhost',4444); # create a tcp connection to the specified host and port $handle = IO::Socket::INET->new( Proto => "tcp", PeerAddr => $host, PeerPort => $port ) or die "can't connect to port $port on $host: $!"; $handle->autoflush(1); # so output gets there right away print STDERR "[Connected to $host:$port]\n"; # split the program into two processes, identical twins die "can't fork: $!" unless defined( $kidpid = fork() ); # the if{} block runs only in the parent process if ($kidpid) { # copy the socket to standard output while ( defined( $line = <$handle> ) ) { print STDOUT $line; } kill( "TERM", $kidpid ); # send SIGTERM to child } # the else{} block runs only in the child process else { # copy standard input to the socket while ( defined( $line = <STDIN> ) ) { print $handle $line; } }