How to Embed Controllers in a Template

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How to Embed Controllers in a Template¶

Note

Rendering embedded controllers is “heavier” than including a template or calling a custom Twig function. Unless you’re planning on caching the fragment, avoid embedding many controllers.

Including template fragments is useful to reuse the same content on several pages. However, this technique is not the best solution in some cases.

Consider a website that displays on its sidebar the most recently published articles. This list of articles is dynamic and it’s probably the result of a database query. In other words, the controller of any page that displays that sidebar must make the same database query and pass the list of articles to the included template fragment.

The alternative solution proposed by Symfony is to create a controller that only displays the list of recent articles and then call to that controller from any template that needs to display that content.

First, create a controller that renders a certain number of recent articles:

// src/Controller/ArticleController.php
namespace App\Controller;

// ...

class ArticleController extends Controller
{
    public function recentArticles($max = 3)
    {
        // make a database call or other logic
        // to get the "$max" most recent articles
        $articles = ...;

        return $this->render(
            'article/recent_list.html.twig',
            array('articles' => $articles)
        );
    }
}

Then, create a recent_list template fragment to list the articles given by the controller:

{# templates/article/recent_list.html.twig #}
{% for article in articles %}
    <a href="{{ path('article_show', {slug: article.slug}) }}">
        {{ article.title }}
    </a>
{% endfor %}

Note

Notice that the article URL is hardcoded in this example (e.g. /article/*slug*). This is a bad practice. In the next section, you’ll learn how to do this correctly.

To include the controller, you’ll need to refer to it using the standard string syntax for controllers (i.e. controllerNamespace::action):

{# templates/base.html.twig #}

{# ... #}
<div id="sidebar">
    {{ render(controller(
        'App\\Controller\\ArticleController::recentArticles',
        { 'max': 3 }
    )) }}
</div>

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.