Mojo::IOLoop::ForkCall and libreoffice to convert a doc file to pdf nonblocking

convert.pl

#!/usr/bin/env perl

use Mojo::Base -strict;
use Mojo::UserAgent;
use Mojo::IOLoop::ForkCall;

my $ua = Mojo::UserAgent->new;
my $fc = Mojo::IOLoop::ForkCall->new;
my $r  = Mojo::IOLoop->recurring(1 => sub { say 'Converting ...' });

my $delay = Mojo::IOLoop->delay;
$delay->steps(
  sub {
    my $delay = shift;
    $ua->get('http://crypto.stanford.edu/DRM2002/darknet5.doc' => $delay->begin);
  },
  sub {
    my ($delay, $tx) = @_;
    my $name = 'darknet5.doc';
    $tx->res->content->asset->move_to($name);
    $fc->run(sub{ `libreoffice --headless --convert-to pdf $name` } => $delay->begin);
  },
  sub {
    my ($delay, $err, $result) = @_;
    Mojo::IOLoop->remove($r);
    print "Conversion result: $result";
  }
);

$delay->wait unless Mojo::IOLoop->is_running;