#!/usr/bin/perl
# This sample sets up two servers. One of them accepts an input feed
# from its clients and broadcasts that input to the clients of the
# other. For lack of a better name, I've called this a tcp bridge.
# This version supports multiple feeds and multiple data consumers.
# Every feed will broadcast to every consumer.
# A lot of people are confused by the array slice convention for event
# handler parameters. The reasons for it are explained here:
# http://poe.perl.org/?POE_FAQ/Why_does_POE_pass_parameters_as_array_s
+lices
# This sample requires POE version 0.1702 or higher. Please see:
# http://poe.perl.org/?Where_to_Get_POE
# About the KERNEL, HEAP, and ARG0-style parameters:
# KERNEL is a reference to POE's main module, POE::Kernel. It holds
# most of the low-level functions for posting events, watching files,
# setting timers, and so on.
# HEAP is a reference to a per-session storage space. If you're
# familiar with threads, it is similar to thread-local storage.
# Because POE includes several runtime context parameters with every
# event, any parameters you include have been pushed to higher places
# in @_. ARG0 is the offset of the first real parameter in @_, and
# ARG1..ARG9 are conveniences. Because the real parameters are always
# at the end of @_, it's possible to retrieve them all at once with:
# my (@args) = @_[ARG0..$#_]
use warnings;
use strict;
# Use POE and also the TCP server component.
use POE qw(Component::Server::TCP Filter::Line);
$/ = 'K';
sub FEED_SERVER_PORT () { 8001 }
sub CONSUMER_SERVER_PORT () { 3001 }
# A helper to log things. You could also use POE::Component::Logger
# to direct logging to a file or syslog.
sub printlog {
my $message_string = join ( "", @_ );
my $date_string = localtime();
print "$date_string $message_string\n";
}
# A table of data consumers. Input from clients attached to the feed
# server will be broadcast to every consumer listed in this table.
my %clients;
# The feed server. Whatever is sent to this server will be broadcast
# to every consumer.
POE::Component::Server::TCP->new
( Port => FEED_SERVER_PORT,
ClientFilter => [ "POE::Filter::Line", Literal =>"K" ], # "\x4B" ]
+,
# A server error occurred. Perform a graceless stop.
Error => sub {
my ( $syscall, $error_number, $error_message ) = @_[ ARG0 .. A
+RG2 ];
die ( "Couldn't start feed server: ",
"$syscall error $error_number: $error_message"
);
},
# Log that a client has connected to the feed server.
ClientConnected => sub {
my $client_id = $_[SESSION]->ID();
printlog("Feed connection $client_id started.");
},
# Log that a client has disconnected from the feed server.
ClientDisconnected => sub {
my $client_id = $_[SESSION]->ID();
printlog("Feed connection $client_id stopped.");
},
# Broadcast all feed input to any data consumers out there. This
# posts a message to each client session, requesting that it send
# the input to its client socket.
ClientInput => sub {
my ( $kernel, $input ) = @_[ KERNEL, ARG0 ];
foreach my $client_id ( keys %clients ) {
$kernel->post( $client_id => send_message => $input );
}
},
);
# The consumer server. Every consumer connection will receive what
# was sent to each feed connection.
POE::Component::Server::TCP->new
( Port => CONSUMER_SERVER_PORT,
#Filter => [ "POE::Filter::Line", Literal => "\x4B" ],
# A server error occurred. Perform a graceless stop.
Error => sub {
my ( $syscall, $error_number, $error_message ) = @_[ ARG0 .. A
+RG2 ];
die ( "Couldn't start consumer server: ",
"$syscall error $error_number: $error_message"
);
},
# Register new connections with the clients table, and log their
# connections.
ClientConnected => sub {
my $client_id = $_[SESSION]->ID();
$clients{$client_id} = "alive";
printlog("Consuming connection $client_id started.");
},
# Remove departing connections from the clients table, and log
# their disconnections.
ClientDisconnected => sub {
my $client_id = $_[SESSION]->ID();
delete $clients{$client_id};
printlog("Consuming connection $client_id stopped.");
},
# Ignore client input. Data consumers cannot talk back to their
# feeds.
ClientInput => sub {
# Do nothing.
},
# Custom event handlers go here. The "send_message" event
# requests that we send something to the client.
InlineStates =>
{ send_message => sub {
my ( $heap, $message ) = @_[ HEAP, ARG0 ];
$heap->{client}->put($message);
},
},
);
# Run the servers until something stops them.
printlog( "Feed server listening on port ", FEED_SERVER_PORT );
printlog( "Consumer server listening on port ", CONSUMER_SERVER_PORT )
+;
$poe_kernel->run();
exit 0;
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