#!/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_slices # 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); sub FEED_SERVER_PORT () { 2000 } sub CONSUMER_SERVER_PORT () { 3000 } # 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 $message_string\n"; } # A table of data consumers. Input from clients attached to the feed # server will be broadcast to every consumer listed in this table. my %clients; # The feed server. Whatever is sent to this server will be broadcast # to every consumer. POE::Component::Server::TCP->new( Port => FEED_SERVER_PORT, # A server error occurred. Perform a graceless stop. Error => sub { my ($syscall, $error_number, $error_message) = @_[ARG0 .. ARG2]; die("Couldn't start feed server: ", "$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 => $input); } }, ); # The consumer server. Every consumer connection will receive what # was sent to each feed connection. POE::Component::Server::TCP->new( Port => CONSUMER_SERVER_PORT, # A server error occurred. Perform a graceless stop. Error => sub { my ($syscall, $error_number, $error_message) = @_[ARG0 .. ARG2]; die("Couldn't start consumer server: ", "$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;