I'm working on creating a local service to listen on localhost and provide a basic call and response type interface. What I'd like to start with is a baby server that you can connect to over telnet and echoes what it receives.

I've heard AnyEvent is great for this, but the documentation for AnyEvent::Socket does not give a very good example how to do this. I'd like to build this with AnyEvent, AnyEvent::Socket and AnyEvent::Handle.

Right now the little server code looks like this:

#!/usr/bin/env perl

use AnyEvent;
use AnyEvent::Handle;
use AnyEvent::Socket;

my $cv = AnyEvent->condvar;

my $host = '127.0.0.1';
my $port = 44244;

tcp_server($host, $port, sub {
    my($fh) = @_;

    my $cv = AnyEvent->condvar;

    my $handle;
    $handle = AnyEvent::Handle->new(
        fh => $fh,
        poll => "r",
        on_read => sub {
             my($self) = @_;
             print "Received: " . $self->rbuf . "\n";
             $cv->send;
        }
    );

    $cv->recv;
});

print "Listening on $host\n";

$cv->wait;

This doesn't work and also if I telnet to localhost:44244 I get this:

EV: error in callback (ignoring): AnyEvent::CondVar: 
recursive blocking wait attempted at server.pl line 29.

I think if I understand how to make a mini, single threaded server that simply prints out whatever its given and then waits for more input, I could take it a lot further from there. Any ideas?