Webservice/Services/ClientAdmin.php

<?php

namespace WebserviceBundle\Services;

use Sonata\AdminBundle\Event\ConfigureEvent;
use WebserviceBundle\Form\Type\RemoteClientType;

class ClientAdmin
{

    /**
     * @param ConfigureEvent $event
     */
    public function addType(ConfigureEvent $event)
    {
        if ($event->getMapper()->has('clientId')) {
            $options = $event->getMapper()->get('clientId')->getOptions();
            $event->getMapper()->add('clientId', RemoteClientType::class, [
                'required' => isset($options['required']) ? $options['required'] : false,
            ]);
        }
    }
    
    /**
     * @param ConfigureEvent $event
     */
    public function addClient(ConfigureEvent $event)
    {
        if ($event->getMapper()->has('clientId')) {
            $clientId = $event->getMapper()->get('clientId');
            $clientId->setType('text');
            $clientId->setTemplate('WebserviceBundle:CRUD:remote_client_field.html.twig');
            $clientId->setOption('data', $event->getType());
        }
    }

}