TitleResolverInterface.php

<?php

namespace Drupal\Core\Controller;

use Symfony\Component\Routing\Route;
use Symfony\Component\HttpFoundation\Request;

/**
 * Defines a class which knows how to generate the title from a given route.
 */
interface TitleResolverInterface {
    
    /**
     * Returns a static or dynamic title for the route.
     *
     * If the returned title can contain HTML that should not be escaped it should
     * return a render array, for example:
     * @code
     * ['#markup' => 'title', '#allowed_tags' => ['em']]
     * @endcode
     * If the method returns a string and it is not marked safe then it will be
     * auto-escaped.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The request object passed to the title callback.
     * @param \Symfony\Component\Routing\Route $route
     *   The route information of the route to fetch the title.
     *
     * @return array|string|null
     *   The title for the route.
     */
    public function getTitle(Request $request, Route $route);

}