Custom controllers

Implementing a custom controller is similar to the vanilla eZ Platform. First, you have to implement it with extending the Site API base controller:

namespace AppBundle\Controller;

use Netgen\Bundle\EzPlatformSiteApiBundle\Controller\Controller;
use Netgen\Bundle\EzPlatformSiteApiBundle\View\ContentView;

class DemoController extends Controller
{
    /**
     * @param \Netgen\Bundle\EzPlatformSiteApiBundle\View\ContentView $view
     *
     * @return \Netgen\Bundle\EzPlatformSiteApiBundle\View\ContentView
     */
    public function viewArticleAction(ContentView $view)
    {
        $content = $view->getSiteContent();
        $location = $view->getSiteLocation();

        $filterService = $this->getSite()->getFilterService();

        $hasRelatedItems = false;

        if ($content->hasField('related') && !$content->getField('related')->isEmpty()) {
            $hasRelatedItems = true;
        }

        // Your other custom logic here
        // ...

        // Add variables to the view
        $view->addParameters([
            'has_related_items' => $hasRelatedItems,
        ]);

        return $view;
    }
}

Since autowiring is enabled, this is sufficient to use your controller in the view configuration:

ezpublish:
    system:
        frontend_group:
            ng_content_view:
                full:
                    article:
                        template: "@App/content/full/article.html.twig"
                        controller: AppBundle\Controller\DemoController:viewArticleAction
                        match:
                            Identifier\ContentType: article