class AjaxBasePageNegotiator in Drupal 10

Defines a theme negotiator that deals with the active theme on ajax requests.

Many different pages can invoke an Ajax request to a generic Ajax path. It is almost always desired for an Ajax response to be rendered using the same theme as the base page, because most themes are built with the assumption that they control the entire page, so if the CSS for two themes are both loaded for a given page, they may conflict with each other. For example, Bartik is Drupal's default theme, and Seven is Drupal's default administration theme. Depending on whether the "Use the administration theme when editing or creating content" checkbox is checked, the node edit form may be displayed in either theme, but the Ajax response to the Field module's "Add another item" button should be rendered using the same theme as the rest of the page.

Hierarchy

• class \Drupal\Core\Theme\AjaxBasePageNegotiator implements \Drupal\Core\Theme\ThemeNegotiatorInterface

1 file declares its use of AjaxBasePageNegotiator

AjaxBasePageNegotiatorTest.php in core/tests/Drupal/Tests/Core/Theme/AjaxBasePageNegotiatorTest.php

1 string reference to 'AjaxBasePageNegotiator'

core.services.yml in core/core.services.yml

core/core.services.yml

1 service uses AjaxBasePageNegotiator

theme.negotiator.ajax_base_page in core/core.services.yml

Drupal\Core\Theme\AjaxBasePageNegotiator

File

core/lib/Drupal/Core/Theme/AjaxBasePageNegotiator.php, line 25

Namespace

Drupal\Core\Theme

class AjaxBasePageNegotiator implements ThemeNegotiatorInterface {

  /**
   * The CSRF token generator.
   *
   * @var \Drupal\Core\Access\CsrfTokenGenerator
   */
  protected $csrfGenerator;

  /**
   * The config factory.
   *
   * @var \Drupal\Core\Config\ConfigFactoryInterface
   */
  protected $configFactory;

  /**
   * The request stack.
   *
   * @var \Symfony\Component\HttpFoundation\RequestStack
   */
  protected $requestStack;

  /**
   * Constructs a new AjaxBasePageNegotiator.
   *
   * @param \Drupal\Core\Access\CsrfTokenGenerator $token_generator
   *   The CSRF token generator.
   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
   *   The config factory.
   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
   *   The request stack used to retrieve the current request.
   */
  public function __construct(CsrfTokenGenerator $token_generator, ConfigFactoryInterface $config_factory, RequestStack $request_stack) {
    $this->csrfGenerator = $token_generator;
    $this->configFactory = $config_factory;
    $this->requestStack = $request_stack;
  }

  /**
   * {@inheritdoc}
   */
  public function applies(RouteMatchInterface $route_match) {
    $ajax_page_state = $this->requestStack
      ->getCurrentRequest()->request
      ->all('ajax_page_state');
    return !empty($ajax_page_state['theme']) && isset($ajax_page_state['theme_token']);
  }

  /**
   * {@inheritdoc}
   */
  public function determineActiveTheme(RouteMatchInterface $route_match) {
    $ajax_page_state = $this->requestStack
      ->getCurrentRequest()->request
      ->all('ajax_page_state');
    $theme = $ajax_page_state['theme'];
    $token = $ajax_page_state['theme_token'];

    // Prevent a request forgery from giving a person access to a theme they
    // shouldn't be otherwise allowed to see. However, since everyone is
    // allowed to see the default theme, token validation isn't required for
    // that, and bypassing it allows most use-cases to work even when accessed
    // from the page cache.
    if ($theme === $this->configFactory
      ->get('system.theme')
      ->get('default') || $this->csrfGenerator
      ->validate($token, $theme)) {
      return $theme;
    }
  }

}