SilexControllerAsAService.php

<?php

class BlogController
{
	/**
	 * @var \Twig_Environment
	 */
	protected $twig;
	
	/**
	 * @var Twig_Environment
	 */
	public function __construct(\Twig_Environment $twig)
	{
		$this->twig = $twig;
	}
	
	/**
	 * @param Request $request
	 */
	public function listAction(Request $request)
	{
		return $this->twig->render....
	}
	
	/**
	 * @param Request $request
	 * @param integer $id
	 */
	public function viewAction(Request $request, $id)
	{
		return $this->twig->render....
	}
}

$app['blog.controller'] = $app->share(function() use ($app) {
    return new BlogController($app['twig']);
});

$blogActions = $app['controllers_factory'];
$blogActions->get('/', 'blog.controller:listAction');
$blogActions->get('/{id}', 'blog.controller:viewAction');

$app->mount('/{_locale}/blog', $blogActions);