EditorController.php

<?php

namespace Drupal\editor;

use Drupal\Core\Controller\ControllerBase;
use Drupal\filter\FilterFormatInterface;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

/**
 * Returns responses for Editor module routes.
 */
class EditorController extends ControllerBase {
    
    /**
     * Apply the necessary XSS filtering for using a certain text format's editor.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The current request object.
     * @param \Drupal\filter\FilterFormatInterface $filter_format
     *   The text format whose text editor (if any) will be used.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     *   A JSON response containing the XSS-filtered value.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
     *   Thrown if no value to filter is specified.
     *
     * @see editor_filter_xss()
     */
    public function filterXss(Request $request, FilterFormatInterface $filter_format) {
        $value = $request->request
            ->get('value');
        if (!isset($value)) {
            throw new NotFoundHttpException();
        }
        // The original_format parameter will only exist when switching text format.
        $original_format_id = $request->request
            ->get('original_format_id');
        $original_format = NULL;
        if (isset($original_format_id)) {
            $original_format = $this->entityTypeManager()
                ->getStorage('filter_format')
                ->load($original_format_id);
        }
        return new JsonResponse(editor_filter_xss($value, $filter_format, $original_format));
    }

}