added support for HTTP foundation Twig extension

doc/providers/twig.rst

@@ -61,6 +61,8 @@ some Symfony components and Twig. Add it as a dependency:
 When present, the ``TwigServiceProvider`` will provide you with the following
 additional capabilities:
 
+* **absolute_url()** and **relative_path()** Twig functions.
+
 * **UrlGeneratorServiceProvider**: If you are using the
   ``UrlGeneratorServiceProvider``, you will have access to the ``path()`` and
   ``url()`` functions. You can find more information in the `Symfony Routing

src/Silex/Provider/TwigServiceProvider.php

@@ -17,6 +17,7 @@ use Symfony\Bridge\Twig\Extension\RoutingExtension;
 use Symfony\Bridge\Twig\Extension\TranslationExtension;
 use Symfony\Bridge\Twig\Extension\FormExtension;
 use Symfony\Bridge\Twig\Extension\SecurityExtension;
+use Symfony\Bridge\Twig\Extension\HttpFoundationExtension;
 use Symfony\Bridge\Twig\Extension\HttpKernelExtension;
 use Symfony\Bridge\Twig\Form\TwigRendererEngine;
 use Symfony\Bridge\Twig\Form\TwigRenderer;
@@ -52,6 +53,8 @@ class TwigServiceProvider implements ServiceProviderInterface
             }
 
             if (class_exists('Symfony\Bridge\Twig\Extension\RoutingExtension')) {
+                $twig->addExtension(new HttpFoundationExtension($app['request_stack']));
+
                 if (isset($app['url_generator'])) {
                     $twig->addExtension(new RoutingExtension($app['url_generator']));
                 }

tests/Silex/Tests/Provider/TwigServiceProviderTest.php

@@ -52,4 +52,19 @@ class TwigServiceProviderTest extends \PHPUnit_Framework_TestCase
         };
         $this->assertEquals('foo', $app['twig.loader']->getSource('foo'));
     }
+
+    public function testHttpFoundationIntegration()
+    {
+        $app = new Application();
+        $app['request_stack']->push(Request::create('/dir1/dir2/file'));
+        $app->register(new TwigServiceProvider(), array(
+            'twig.templates' => array(
+                'absolute' => '{{ absolute_url("foo.css") }}',
+                'relative' => '{{ relative_path("/dir1/foo.css") }}',
+            ),
+        ));
+
+        $this->assertEquals('http://localhost/dir1/dir2/foo.css', $app['twig']->render('absolute'));
+        $this->assertEquals('../foo.css', $app['twig']->render('relative'));
+    }
 }