added converters for request attributes

doc/usage.rst

@@ -228,6 +228,41 @@ While it's not suggested, you could also do this (note the switched arguments)::
         ...
     });
 
+Route variables converters
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Before injecting the route variables into the controller, you can apply some
+converters::
+
+    $app->get('/user/{id}', function ($id) {
+        // ...
+    })->convert('id', function ($id) { return (int) $id; });
+
+This is useful when you want to convert route variables to objects as it
+allows to reuse the conversion code across different controllers::
+
+    $userProvider = function ($id) {
+        return new User($id);
+    };
+
+    $app->get('/user/{user}', function (User $user) {
+        // ...
+    })->convert('user', $userProvider);
+
+    $app->get('/user/{user}/edit', function (User $user) {
+        // ...
+    })->convert('user', $userProvider);
+
+The converter callback also receives the ``Request`` as its second argument::
+
+    $callback = function ($post, Request $request) {
+        return new Post($request->attributes->get('slug'));
+    };
+
+    $app->get('/blog/{id}/{slug}', function (Post $post) {
+        // ...
+    })->convert('post', $callback);
+
 Requirements
 ~~~~~~~~~~~~
 

src/Silex/Application.php

@@ -17,6 +17,7 @@ use Symfony\Component\HttpKernel\Controller\ControllerResolver;
 use Symfony\Component\HttpKernel\Event\KernelEvent;
 use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
+use Symfony\Component\HttpKernel\Event\FilterControllerEvent;
 use Symfony\Component\HttpKernel\Exception\MethodNotAllowedHttpException;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\HttpKernel\Events as HttpKernelEvents;
@@ -347,6 +348,22 @@ class Application extends \Pimple implements HttpKernelInterface, EventSubscribe
         $this['dispatcher']->dispatch(Events::onSilexBefore);
     }
 
+    /**
+     * Handles converters.
+     *
+     * @param FilterControllerEvent $event A FilterControllerEvent instance
+     */
+    public function onCoreController(FilterControllerEvent $event)
+    {
+        $request = $event->getRequest();
+        $route = $this['routes']->get($request->attributes->get('_route'));
+        if ($route && $converters = $route->getOption('_converters')) {
+            foreach ($converters as $name => $callback) {
+                $request->attributes->set($name, call_user_func($callback, $request->attributes->get($name, null), $request));
+            }
+        }
+    }
+
     /**
      * Handles string responses.
      *
@@ -396,6 +413,7 @@ class Application extends \Pimple implements HttpKernelInterface, EventSubscribe
 
         return array(
             HttpKernelEvents::onCoreRequest,
+            HttpKernelEvents::onCoreController,
             HttpKernelEvents::onCoreResponse,
             HttpKernelEvents::onCoreException,
         );

src/Silex/Controller.php

@@ -95,6 +95,21 @@ class Controller
         return $this;
     }
 
+    /**
+     * Sets a converter for a route variable.
+     *
+     * @param string $variable The variable name
+     * @param mixed  $callback A PHP callback that converts the original value
+     */
+    public function convert($variable, $callback)
+    {
+        $converters = $this->route->getOption('_converters');
+        $converters[$variable] = $callback;
+        $this->route->setOption('_converters', $converters);
+
+        return $this;
+    }
+
     /**
      * Freezes the controller.
      *

tests/Silex/Tests/ApplicationTest.php

@@ -85,6 +85,25 @@ class ApplicationTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(2, count($routes->all()));
     }
 
+    public function testOnCoreController()
+    {
+        $app = new Application();
+
+        $app->get('/foo/{foo}', function (\ArrayObject $foo) {
+            return $foo['foo'];
+        })->convert('foo', function ($foo) { return new \ArrayObject(array('foo' => $foo)); });
+
+        $response = $app->handle(Request::create('/foo/bar'));
+        $this->assertEquals('bar', $response->getContent());
+
+        $app->get('/foo/{foo}/{bar}', function (\ArrayObject $foo) {
+            return $foo['foo'];
+        })->convert('foo', function ($foo, Request $request) { return new \ArrayObject(array('foo' => $foo.$request->attributes->get('bar'))); });
+
+        $response = $app->handle(Request::create('/foo/foo/bar'));
+        $this->assertEquals('foobar', $response->getContent());
+    }
+
     /**
     * @dataProvider escapeProvider
     */

tests/Silex/Tests/ControllerTest.php

@@ -60,6 +60,15 @@ class ControllerTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(array('bar' => 'foo'), $controller->getRoute()->getDefaults());
     }
 
+    public function testConvert()
+    {
+        $controller = new Controller(new Route('/foo/{bar}'));
+        $ret = $controller->convert('bar', $func = function ($bar) { return $bar; });
+
+        $this->assertSame($ret, $controller);
+        $this->assertEquals(array('bar' => $func), $controller->getRoute()->getOption('_converters'));
+    }
+
     /**
      * @dataProvider provideRouteAndExpectedRouteName
      */