Issue #3272370 by e0ipso: Pass arguments as JSON encoded for the render endpoint

namespace Drupal\cl_server\Controller;

use Drupal\cl_components\Component\Component;

use Drupal\cl_components\Component\ComponentDiscovery;

use Drupal\cl_components\Exception\ComponentNotFoundException;

use Drupal\Component\Serialization\Json;

use Drupal\Core\Controller\ControllerBase;

use Drupal\cl_components\Component\Component;

use Drupal\cl_components\Component\ComponentDiscovery;

use Drupal\Core\PageCache\ResponsePolicy\KillSwitch;

use Symfony\Component\DependencyInjection\ContainerInterface;

use Symfony\Component\HttpFoundation\Request;

   *   The array of arguments.

   */

  private function getArguments(Request $request): array {

    $arguments = [];

    foreach ($request->query->all() as $key => $value) {

      if ($key[0] === '_') {

        continue;

      }

      $arguments[$key] = is_scalar($value) ? $value : Json::decode($value);

    }

    return $arguments;

    return Json::decode($request->query->get('_params'));

  }

  /**