RequestHelper.php

<?php

namespace Drupal\Core\Routing;

use Symfony\Component\HttpFoundation\Request;

/**
 * Provides some helper methods for dealing with the request.
 */
class RequestHelper {
    
    /**
     * Returns whether the request is using a clean URL.
     *
     * A clean URL is one that does not include the script name. For example,
     * - http://example.com/node/1 is a clean URL.
     * - http://example.com/index.php/node/1 is not a clean URL.
     *
     * Unclean URLs are required on sites hosted by web servers that cannot be
     * configured to implicitly route URLs to index.php.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The request.
     *
     * @return bool
     *   TRUE if the request is using a clean URL.
     */
    public static function isCleanUrl(Request $request) {
        $base_url = $request->getBaseUrl();
        return empty($base_url) || strpos($base_url, $request->getScriptName()) === FALSE;
    }

}