Symfony Twig：获取内核根目录

Question

我在Symfony项目中设置了以下配置：

twig:
    debug: '%kernel.debug%'
    strict_variables: '%kernel.debug%'
    globals:
      web_dir: "%kernel.root_dir%/../web"

我已经完成了以下twig symnfony函数（如Symfony generate cdn friendly asset url中所示）：

namespace AppBundle\Twig;

class AllExtentions extends \Twig_Extension
{
  public function getFunctions()
  {
      return array(
          new \Twig_SimpleFunction('versionedAsset',array($this,'versionedAsset'))
      );
  }


  /**
     * Gebnerate a cdn friendly url for the assets.
     * @param string $path The url of the path RELATIVE to the css.
     * @return string
     */
    public function versionedWebAsset($path)
    {
        // Set the value of the web_dir global
        // $webDir=
        $hash=hash_file("sha512",$path);
        return $path."?v=".$hash;
    }

}

我的问题在于我如何将web_dir全局的值转换为versionedAsset函数？

编辑1

我使用Symfony的autowire并自动装配/自动配置AllExtentions类：

use Symfony\Component\DependencyInjection\Definition;
use Symfony\Component\DependencyInjection\Reference;

// To use as default template
$definition = new Definition();

$definition
->setAutowired(true)
->setAutoconfigured(true)
->setPublic(false);

$this->registerClasses($definition, 'AppBundle\\', '../../src/AppBundle/*', '../../src/AppBundle/{Entity,Repository,Resources,Tests}');

Answer 1

您可以通过将您的扩展程序声明为服务，然后将服务容器传递给它来实现此目的：

twig.all.extensions:
    class: AppBundle\Twig\AllExtentions
    arguments:
        - @service_container
    tags:
        - { name: twig.extension }

之后，在您的扩展程序中添加__construct()方法并使用它来获取web_dir变量：

/**
* ContainerInterface $container
*/
public function __construct($container)
{
  $this->container = $container;
}

/**
 * Gebnerate a cdn friendly url for the assets.
 * @param string $path The url of the path RELATIVE to the css.
 * @return string
 */
public function versionedWebAsset($path)
{
    $webDir=$this->container->get('twig')->getGlobals()['web_dir'];
    $hash=hash_file("sha512",$path);
    return $path."?v=".$hash;
}