Filtering in Mojolicious

gistfile1.pl

# Some values.
my ($a, $b, $c) = ('hallo', 'foo', 'bar');

# Emit a filter hook
$c->filter(
  'on_database_access' =>
    \$a, \$b, \$c =>
      sub {    # Do whenever all subscribers are done.
	print $a,"\n";
      }
    );

# Establish a filter on an event.
# This can be async
$c->hook_on_filter(
  'on_database_access' => sub {
    my ($filter, $a_ref, $b_ref, $c_ref) = @_;
    $$a_ref =~ s/a/e/;

    # I don't know if this is needed.
    # Just a next tick thing,
    # executing the callback of the next filter in chain
    $filter->next;
  });