given/when dispatch

app.pl

sub call {
  my ($self, $env) = @_;

  given ([$env->{REQUEST_METHOD}, $env->{PATH_INFO}]) {
    when ([GET => "/"]) {
      return $self->index;
    }
    when ([POST => qr{^/track/?$}]) {
      return $self->upload($env);
    }
    when ([GET => qr{^/([0-9a-f]{32})/?$}]) {
      return $self->track($1);
    }
    default {
      return $self->redirect("/");
    }
  }
}