MainContentViewSubscriber.php

Same filename in other branches
  1. 8.9.x core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php
  2. 10 core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php
  3. 11.x core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php

Namespace

Drupal\Core\EventSubscriber

File

core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php

View source
<?php

namespace Drupal\Core\EventSubscriber;

use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Cache\CacheableResponseInterface;
use Drupal\Core\DependencyInjection\ClassResolverInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\Event\ViewEvent;
use Symfony\Component\HttpKernel\KernelEvents;

/**
 * View subscriber rendering main content render arrays into responses.
 *
 * Additional target rendering formats can be defined by adding another service
 * that implements \Drupal\Core\Render\MainContent\MainContentRendererInterface
 * and tagging it as a @code render.main_content_renderer @endcode, then
 * \Drupal\Core\Render\MainContent\MainContentRenderersPass will detect it and
 * use it when appropriate.
 *
 * @see \Drupal\Core\Render\MainContent\MainContentRendererInterface
 * @see \Drupal\Core\Render\MainContentControllerPass
 */
class MainContentViewSubscriber implements EventSubscriberInterface {
    
    /**
     * The class resolver service.
     *
     * @var \Drupal\Core\DependencyInjection\ClassResolverInterface
     */
    protected $classResolver;
    
    /**
     * The current route match.
     *
     * @var \Drupal\Core\Routing\RouteMatchInterface
     */
    protected $routeMatch;
    
    /**
     * The available main content renderer services, keyed per format.
     *
     * @var array
     */
    protected $mainContentRenderers;
    
    /**
     * URL query attribute to indicate the wrapper used to render a request.
     *
     * The wrapper format determines how the HTML is wrapped, for example in a
     * modal dialog.
     */
    const WRAPPER_FORMAT = '_wrapper_format';
    
    /**
     * Constructs a new MainContentViewSubscriber object.
     *
     * @param \Drupal\Core\DependencyInjection\ClassResolverInterface $class_resolver
     *   The class resolver service.
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The current route match.
     * @param array $main_content_renderers
     *   The available main content renderer service IDs, keyed by format.
     */
    public function __construct(ClassResolverInterface $class_resolver, RouteMatchInterface $route_match, array $main_content_renderers) {
        $this->classResolver = $class_resolver;
        $this->routeMatch = $route_match;
        $this->mainContentRenderers = $main_content_renderers;
    }
    
    /**
     * Sets a response given a (main content) render array.
     *
     * @param \Symfony\Component\HttpKernel\Event\ViewEvent $event
     *   The event to process.
     */
    public function onViewRenderArray(ViewEvent $event) {
        $request = $event->getRequest();
        $result = $event->getControllerResult();
        // Render the controller result into a response if it's a render array.
        if (is_array($result) && ($request->query
            ->has(static::WRAPPER_FORMAT) || $request->getRequestFormat() == 'html')) {
            $wrapper = $request->query
                ->get(static::WRAPPER_FORMAT, 'html');
            // Fall back to HTML if the requested wrapper envelope is not available.
            $wrapper = isset($this->mainContentRenderers[$wrapper]) ? $wrapper : 'html';
            $renderer = $this->classResolver
                ->getInstanceFromDefinition($this->mainContentRenderers[$wrapper]);
            $response = $renderer->renderResponse($result, $request, $this->routeMatch);
            // The main content render array is rendered into a different Response
            // object, depending on the specified wrapper format.
            if ($response instanceof CacheableResponseInterface) {
                $main_content_view_subscriber_cacheability = (new CacheableMetadata())->setCacheContexts([
                    'url.query_args:' . static::WRAPPER_FORMAT,
                ]);
                $response->addCacheableDependency($main_content_view_subscriber_cacheability);
            }
            $event->setResponse($response);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() {
        $events[KernelEvents::VIEW][] = [
            'onViewRenderArray',
        ];
        return $events;
    }

}

Classes

Title Deprecated Summary
MainContentViewSubscriber View subscriber rendering main content render arrays into responses.

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.