HttpKernel provides the building blocks to create flexible and fast HTTP-based frameworks.
HttpKernelInterface is the core interface of the Symfony2 full-stack framework:
interface HttpKernelInterface { /** * Handles a Request to convert it to a Response. * * @param Request $request A Request instance * * @return Response A Response instance */ function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true); } It takes a Request as an input and should return a Response as an output. Using this interface makes your code compatible with all frameworks using the Symfony2 components. And this will gives you many cool features for free.
Creating a framework based on the Symfony2 components is really easy. Here is a very simple, but fully-featured framework based on the Symfony2 components:
$routes = new RouteCollection(); $routes->add('hello', new Route('/hello', array('_controller' => function (Request $request) { return new Response(sprintf("Hello %s", $request->get('name'))); } ))); $request = Request::createFromGlobals(); $context = new RequestContext(); $context->fromRequest($request); $matcher = new UrlMatcher($routes, $context); $dispatcher = new EventDispatcher(); $dispatcher->addSubscriber(new RouterListener($matcher)); $resolver = new ControllerResolver(); $kernel = new HttpKernel($dispatcher, $resolver); $kernel->handle($request)->send(); This is all you need to create a flexible framework with the Symfony2 components.
Want to add an HTTP reverse proxy and benefit from HTTP caching and Edge Side Includes?
$kernel = new HttpKernel($dispatcher, $resolver); $kernel = new HttpCache($kernel, new Store(__DIR__.'/cache')); Want to functional test this small framework?
$client = new Client($kernel); $crawler = $client->request('GET', '/hello/Fabien'); $this->assertEquals('Fabien', $crawler->filter('p > span')->text()); Want nice error pages instead of ugly PHP exceptions?
$dispatcher->addSubscriber(new ExceptionListener(function (Request $request) { $msg = 'Something went wrong! ('.$request->get('exception')->getMessage().')'; return new Response($msg, 500); })); And that's why the simple looking HttpKernelInterface is so powerful. It gives you access to a lot of cool features, ready to be used out of the box, with no efforts.
You can run the unit tests with the following command:
phpunit -c src/Symfony/Component/HttpKernel/ If you also want to run the unit tests that depend on other Symfony Components, declare the following environment variables before running PHPUnit:
export SYMFONY_EVENT_DISPATCHER=../path/to/EventDispatcher export SYMFONY_HTTP_FOUNDATION=../path/to/HttpFoundation export SYMFONY_DEPENDENCY_INJECTION=../path/to/DependencyInjection export SYMFONY_CONSOLE=../path/to/Console export SYMFONY_BROWSER_KIT=../path/to/BrowserKit export SYMFONY_FINDER=../path/to/Finder export SYMFONY_PROCESS=../path/to/Process export SYMFONY_ROUTING=../path/to/Routing export SYMFONY_CONFIG=../path/to/Config 
