Inject services from Pimple Container in Controller arguments

ControllerResolver.php

<?php

namespace Controller;
use Silex\ControllerResolver as SilexControllerResolver;
use Symfony\Component\HttpFoundation\Request;
use \Pimple;
/**
 * Extension of Silex\ControllerResolver, as that injects Application class if
 * its requested by Controller by Typehinting; this looks for, and injects,
 * services with same name as parameter argument and validates is the right
 * class of the service.
 * 
 * Example:
 * You have a service, say a DBAL\Connection; accesible at $app['db'];
 * Then you can inject it to your Controller, Typehinting and naming a parameter
 * same Type as your Service, same name as the key in the ArrayAccess Object.
 * // use Doctrine\DBAL\Connection;
 * Class TestNameInjection
 * {
 *   public function indexAction(Connection $db){
 *     return new Response("OK");
 *   }
 * }
 * This implementation is linked to the getArguments call of the
 * ControllerResolver to load your Controller. Register it like this:
 * $container['resolver'] = $container->share(function($container) {
 *   new Controller\ControllerResolver($container); 
 * });
 * @author Jesus E. Franco Martinez <jefrancomix@gmail.com>
 */
class ControllerResolver extends SilexControllerResolver
{
    public function __construct(Pimple $c)
    {
        $this->app = $c;
    }
    protected function doGetArguments(Request $request, $controller, array $parameters)
    {
        $keys = $this->app->keys();
        foreach ($parameters as $param) {
            if($param->getClass() != null && in_array($param->name, $keys)) {
                $this->lookupInContainer($param, $request);
            }
        }
        return parent::doGetArguments($request, $controller, $parameters);
    }
    private function lookupInContainer(\ReflectionParameter $param, Request $request)
    {
        $name = $param->name;
        $class = $param->getClass();
        $maybeObject = $this->app[$name];
        if(is_object($maybeObject) && $class->isInstance($maybeObject)) {
            $request->attributes->set($name, $maybeObject);
        }
    }
}