This seems to be either a timer or timeout+retry problem. If you respond right away, it works as expected.

use strict;
use warnings;

use AnyEvent::HTTPD;

my $h = AnyEvent::HTTPD->new(port => 8123);;

my $requests = {};
my $requestCounter = 0;

$h->reg_cb (
    '/test' => sub {
        my ($httpd,$req) = @_;

        my $request = $requestCounter;
        $requestCounter++;

        print "Starting response for ", $req->{method}, " request $req
+uest\n";

        $req->respond(
            [200, 'ok',
                { 'Content-Type' => 'text/html'
                },
                '<h1>Test</h1>'
            ]);
    }
);

my $c = AnyEvent::condvar;
$c->recv();
[download]

Why do you want to wait instead of responding as soon as possible?

If you want to wait for an event to happen, the modern way is to either use Websockets or Push notifications. If you can't do either of those (please explain why), then the proper fallback to handle this would be cyclic calls from client to server to "pull" not yet handled events.

Leaving standard GET requests just "hanging" will lead to a number of different things:

• Wasted resources on the server
• Timeouts
• Modern browsers marking the connection to your server as unreliable, therefore increasing the number of parallel TCP connections they will open to try and get a result.
• Customer complaints
• Getting shouted at by your system administrator