feature #1508 Added WebLink component integration (skalpa)

This PR was merged into the 2.1.x-dev branch.

Discussion
----------

Added WebLink component integration

I made the necessary changes to support the new WebLink component:

- `HttpKernelServiceProvider` registers the `AddLinkHeaderListener` if the component is available
- `TwigServiceProvider` adds the `WebLinkExtension` if the component and the Twig bridge are available
- Both changes are tested
- The documentation has been amended (the link to the Symfony website doesn't work as 3.3 hasn't been released yet but I believe it's the good URL)

Commits
-------

37bd5ae Added WebLink component integration

composer.json

@@ -47,7 +47,8 @@
         "twig/twig": "~1.28|~2.0",
         "doctrine/dbal": "~2.2",
         "swiftmailer/swiftmailer": "~5",
-        "monolog/monolog": "^1.4.1"
+        "monolog/monolog": "^1.4.1",
+        "symfony/web-link": "^3.3"
     },
     "replace": {
         "silex/api": "self.version",

doc/providers/twig.rst

@@ -134,6 +134,15 @@ If you are using the ``SecurityServiceProvider``, you will have access to the
 `Symfony Security documentation
 <http://symfony.com/doc/current/book/security.html#access-control-in-templates>`_.
 
+Web Link Support
+~~~~~~~~~~~~~~~~
+
+If you are using the ``symfony/web-link`` component, you will have access to the
+``preload()``, ``prefetch()``, ``prerender()``, ``dns_prefetch()``,
+``preconnect()`` and ``link()`` functions in templates. You can find more
+information in the `Symfony WebLink documentation
+<https://symfony.com/doc/current/components/weblink/introduction.html>`_.
+
 Global Variable
 ~~~~~~~~~~~~~~~
 

src/Silex/Provider/HttpKernelServiceProvider.php

@@ -24,6 +24,8 @@
 use Symfony\Component\HttpKernel\EventListener\ResponseListener;
 use Symfony\Component\HttpKernel\HttpKernel;
 use Symfony\Component\HttpKernel\Kernel;
+use Symfony\Component\WebLink\EventListener\AddLinkHeaderListener;
+use Symfony\Component\WebLink\HttpHeaderSerializer;
 
 class HttpKernelServiceProvider implements ServiceProviderInterface, EventListenerProviderInterface
 {
@@ -91,5 +93,9 @@ public function subscribe(Container $app, EventDispatcherInterface $dispatcher)
         $dispatcher->addSubscriber(new MiddlewareListener($app));
         $dispatcher->addSubscriber(new ConverterListener($app['routes'], $app['callback_resolver']));
         $dispatcher->addSubscriber(new StringToResponseListener());
+
+        if (class_exists(HttpHeaderSerializer::class)) {
+            $dispatcher->addSubscriber(new AddLinkHeaderListener());
+        }
     }
 }

src/Silex/Provider/TwigServiceProvider.php

@@ -23,9 +23,11 @@
 use Symfony\Bridge\Twig\Extension\SecurityExtension;
 use Symfony\Bridge\Twig\Extension\HttpFoundationExtension;
 use Symfony\Bridge\Twig\Extension\HttpKernelExtension;
+use Symfony\Bridge\Twig\Extension\WebLinkExtension;
 use Symfony\Bridge\Twig\Form\TwigRendererEngine;
 use Symfony\Bridge\Twig\Form\TwigRenderer;
 use Symfony\Bridge\Twig\Extension\HttpKernelRuntime;
+use Symfony\Component\WebLink\HttpHeaderSerializer;
 
 /**
  * Twig integration for Silex.
@@ -142,6 +144,10 @@ public function register(Container $app)
                 if (class_exists(HttpKernelRuntime::class)) {
                     $twig->addRuntimeLoader($app['twig.runtime_loader']);
                 }
+
+                if (class_exists(HttpHeaderSerializer::class) && class_exists(WebLinkExtension::class)) {
+                    $twig->addExtension(new WebLinkExtension($app['request_stack']));
+                }
             }
 
             return $twig;

tests/Silex/Tests/ApplicationTest.php

@@ -11,6 +11,8 @@
 
 namespace Silex\Tests;
 
+use Fig\Link\GenericLinkProvider;
+use Fig\Link\Link;
 use Silex\Application;
 use Silex\ControllerCollection;
 use Silex\Api\ControllerProviderInterface;
@@ -655,6 +657,22 @@ public function testViewListenersResponsesAreNotUsedIfNull()
         $this->assertEquals('Hello view listener', $response->getContent());
     }
 
+    public function testWebLinkListener()
+    {
+        $app = new Application();
+
+        $app->get('/', function () {
+            return 'hello';
+        });
+
+        $request = Request::create('/');
+        $request->attributes->set('_links', (new GenericLinkProvider())->withLink(new Link('preload', '/foo.css')));
+
+        $response = $app->handle($request);
+
+        $this->assertEquals('</foo.css>; rel="preload"', $response->headers->get('Link'));
+    }
+
     public function testDefaultRoutesFactory()
     {
         $app = new Application();

tests/Silex/Tests/Provider/TwigServiceProviderTest.php

@@ -11,11 +11,13 @@
 
 namespace Silex\Tests\Provider;
 
+use Fig\Link\Link;
 use Silex\Application;
 use Silex\Provider\CsrfServiceProvider;
 use Silex\Provider\FormServiceProvider;
 use Silex\Provider\TwigServiceProvider;
 use Silex\Provider\AssetServiceProvider;
+use Symfony\Bridge\Twig\Extension\WebLinkExtension;
 use Symfony\Component\HttpFoundation\Request;
 
 /**
@@ -138,4 +140,24 @@ public function testFormatParameters()
         $this->assertSame($timezone, $twig->getExtension('Twig_Extension_Core')->getTimezone());
         $this->assertSame(array(2, ',', ' '), $twig->getExtension('Twig_Extension_Core')->getNumberFormat());
     }
+
+    public function testWebLinkIntegration()
+    {
+        if (!class_exists(WebLinkExtension::class)) {
+            $this->markTestSkipped('Twig WebLink extension not available.');
+        }
+
+        $app = new Application();
+        $app['request_stack']->push($request = Request::create('/'));
+        $app->register(new TwigServiceProvider(), array(
+            'twig.templates' => array(
+                'preload' => '{{ preload("/foo.css") }}',
+            ),
+        ));
+
+        $this->assertEquals('/foo.css', $app['twig']->render('preload'));
+
+        $link = new Link('preload', '/foo.css');
+        $this->assertEquals(array($link), array_values($request->attributes->get('_links')->getLinks()));
+    }
 }