cro-ephemeral-port.raku

#!/usr/bin/env raku
use v6.d;

use Cro::HTTP::Server;
use Cro::HTTP::Router;

my $application = route {
    get -> {
        content 'text/html', 'Hello World';
    }
}

# Basically a copy of Cro::TCP::Listener, but doesn't bother with
# allowing nodelay to be set and grabs the port number with a nest of
# tap and supplier.
class NuListener does Cro::Source {
    has Str $.host = 'localhost';
    has Cro::Port $.port is required;

    method produces() { Cro::TCP::ServerConnection }

    method incoming() {
        my $listen-socket = IO::Socket::Async.listen($!host, $!port);
        my $supplier = Supplier::Preserving.new();
        my $tap = $listen-socket.tap( { $supplier.emit($_) } );
        $!port = $tap.socket-port.result;

        supply {
            whenever $supplier.Supply() -> $socket {
                emit Cro::TCP::ServerConnection.new(:$socket);
            }
        }
    }
}

my Cro::Service $service = Cro::HTTP::Server.new(
    :host('localhost'), :port(0), :$application
);

# Swap out the TCP component...
$service.components[0] = NuListener.new(:host('localhost'), :port(0));

$service.start;
my $ephemeral-port = $service.components[0].port;

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