icingaweb2-module-director/library/Director/PropertyModifier/PropertyModifierLowercase.php

<?php

namespace Icinga\Module\Director\PropertyModifier;

use Icinga\Module\Director\Hook\PropertyModifierHook;

class PropertyModifierLowercase extends PropertyModifierHook
{
    public function transform($value)
    {
        if ($value === null) {
            return null;
        }

        return \mb_strtolower($value, 'UTF-8');
    }
}