Symfony Internals - Speaker Deck

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Symfony Internals

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Symfony Internals Andreas Hucks CTO @ SensioLabs Germany

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2008

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Conference Hotel

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Auditorium

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Lunch

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Socials

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VIP Lounge

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Wellness

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Survey

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Motivation

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What to expect

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The Request $kernel = new Kernel($env, $debug); $request = Request::createFromGlobals(); $response = $kernel->handle($request); $response->send();

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HttpKernel $kernel->handle($request);

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Request-Response Flow Request Response Front  Controller Kernel

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Symfony is not an  MVC framework

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No content

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Symfony is a  Request-Response Framework

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Request-Response Flow Request Response Front  Controller Kernel

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Request-Response Flow Kernel

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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EventDispatcher $dispatcher = new EventDispatcher(); $dispatcher->addListener('kernel.request', $callable);

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EventDispatcher $dispatcher->dispatch( 'kernel.request', $responseEvent );

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EventDispatcher $dispatcher->dispatch( 'kernel.request', $responseEvent ); payload What happened.

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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GetResponseEvent class GetResponseEvent extends KernelEvent { public function getResponse() { return $this->response; } public function setResponse(Response $response) { $this->response = $response; $this->stopPropagation(); } kernel.request

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RouterListener /** * @Route(path="/books/{id}", name="book_show") */ $params = [ '_controller' => ‘App\Controller\BookController::showAction’, '_route' => 'book_show', '_route_params' => [ 'id' => '37' ], 'id' => ’37' ]; kernel.request

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RouterListener $parameters = $this ->matcher->match($request->getPathInfo()); $request->attributes->add($parameters); unset( $parameters[‘_route'], $parameters[‘_controller'] ); $request->attributes->set( '_route_params', $parameters ); kernel.request

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LocaleListener $request = $event->getRequest(); $request->setDefaultLocale($this->defaultLocale); if ($locale = $request->attributes->get('_locale')) { $request->setLocale($locale); } kernel.request

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Customize! • Content Negotiation - Parse headers and add attribute • Verify signed Cookies • Redirects based on arbitrary criteria • Custom Locale stuff • … ?

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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FilterControllerEvent class FilterControllerEvent extends KernelEvent { public function getController() { return $this->controller; } public function setController(callable $controller) { $this->controller = $controller; } kernel.controller

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ControllerListener class ControllerListener implements EventSubscriberInterface { public function __construct(Reader $reader) { $this->reader = $reader; } public function onKernelController(FilterControllerEvent $event) { $controller = $event->getController(); // read annotations for class and method $request = $event->getRequest(); foreach ($configurations as $key => $attributes) { $request->attributes->set($key, $attributes); } kernel.controller

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ParamConverterListener class ParamConverterListener implements EventSubscriberInterface { /** * @var ParamConverterManager */ private $manager; kernel.controller

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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Wait… Controllers?

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HttpKernel $response = \call_user_func_array( $controller, $arguments );

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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GetResponseForControllerResultEvent class GetResponseForControllerResultEvent extends GetResponseEvent { public function getControllerResult() { return $this->controllerResult; } public function setControllerResult($controllerResult) { $this->controllerResult = $controllerResult; } kernel.view

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TemplateListener public function onKernelView( GetResponseForControllerResultEvent $event ) { /* @var Template $template */ $request = $event->getRequest(); $template = $request->attributes->get(‘_template'); // … $event->setResponse( new Response( $this->twig->render($template->getTemplate()), $parameters ) ); kernel.view

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Customize! • Auto serializing and encoding for web service responses • Together with kernel.controller:   Action Domain Responder, other patterns?

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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GetResponseForExceptionEvent class GetResponseForExceptionEvent extends GetResponseEvent { public function getException() { return $this->exception; } kernel.exception

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ExceptionListener public function onKernelException( GetResponseForExceptionEvent $event ) { $exception = $event->getException(); $request = $event->getRequest(); $this->logException($exception kernel.exception

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Customize! • Customize for every exception type you like • Redirect for some errors • “were you looking for…” suggestions on 404 pages • Custom alerts • … ?

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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FilterResponseEvent class FilterResponseEvent extends KernelEvent { public function getResponse() { return $this->response; } public function setResponse(Response $response) { $this->response = $response; } kernel.response

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WebDebugToolbarListener $response->headers->set( 'X-Debug-Token-Link', $this->urlGenerator->generate( ‘_profiler', array( 'token' => $response->headers->get(‘X-Debug-Token') ), UrlGeneratorInterface::ABSOLUTE_URL ) ); $this->injectToolbar($response, $request, $nonces); kernel.response

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SaveSessionListener $session = $event->getRequest()->getSession(); if ($session && $session->isStarted()) { $session->save(); $event->getResponse() ->setPrivate() ->setMaxAge(0) ->headers->addCacheControlDirective('must-revalidate'); } kernel.response

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Customize! • Sign cookies • Add custom headers • … ?

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Request-Response Flow Kernel kernel.request kernel.controller kernel.response kernel.exception kernel.view kernel.terminate

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PostResponseEvent class PostResponseEvent extends KernelEvent { public function getResponse() { return $this->response; } kernel.terminate

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EmailSenderListener public function onTerminate() { // send spooled Emails kernel.terminate

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Other Listeners kernel.request • FirewallListener • Collector Listeners

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Recap Request Response Front  Controller Kernel

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Container & Cache

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Container & Cache protected function getRouterService() { $this->services[‘router'] = $instance = new \Symfony\Bundle\…\Router( $this, ‘/app/config/routing_dev.yml' ) // [snip] return $instance; }

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Container & Cache Cache class for this request? Does it exists? require() it yes Build Container no

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Container & Cache Cache class for this request? Does it exists? require() it yes Build Container no

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers (quite a few)

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Registering Bundles public function registerBundles() { $bundles = [ new Symfony\Bundle\FrameworkBundle\FrameworkBundle(), new Symfony\Bundle\SecurityBundle\SecurityBundle(), new Symfony\Bundle\TwigBundle\TwigBundle(), // [snip] ]; return $bundles; }

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Registering Extensions protected function prepareContainer(ContainerBuilder $container) { $extensions = array(); foreach ($this->bundles as $bundle) { if ($extension = $bundle->getContainerExtension()) { $container->registerExtension($extension); $extensions[] = $extension->getAlias(); } // [snip] }

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Register Project-Level Container Conﬁg public function registerContainerConfiguration( LoaderInterface $loader ) { $loader->load( $this->getRootDir(). ’/config/config_’.$this->getEnvironment().'.yml' ); }

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Extensions class TwigExtension extends Extension { public function load(array $configs, ContainerBuilder $container) { $loader = new XmlFileLoader( $container, new FileLocator(__DIR__.’/../Resources/config') ); $loader->load('twig.xml');

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Customize! • Load config files • Do not load config files depending on parameter • Set Parameters, manipulate parameters • BETTER NOT manipulate services (they are not complete at this point, see next slides)

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Compiler Passes public function process(ContainerBuilder $container) { if (!$container->has('app.myservice')) { return; } $definition = $container->findDefinition( 'app.myservice' ); // find formatter service $definition->addMethodCall( 'addFormatter', array(new Reference($formatterId)) ); }

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(A few) Compiler Passes • ServiceLocatorTagPass • DecoratorServicePass • ResolveParameterPlaceHoldersPass • ResolveFactoryClassPass • ResolveNamedArgumentsPass • AutowirePass • RemovePrivateAliasesPass • ReplaceAliasByActualDefinitionPass • RemoveAbstractDefinitionsPass • InlineServiceDefinitionsPass • RemoveUnusedDefinitionsPass

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Customize! • Add method calls to services based on tags • Manipulate services that depend on the full service conﬁg

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Dump Container protected function dumpContainer( ConfigCache $cache, ContainerBuilder $container, $class, $baseClass ) { $dumper = new PhpDumper($container); $content = $dumper->dump(/*…*/);

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… and use it $this->container = require $cache->getPath();

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Container Build Register Bundles Register Extensions & Compiler Passes Register Project Conﬁg Run Extensions Run compiler Passes Dump Container Run Cache Warmers

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Cache Warmers public function warmUp($cacheDir) { $filesystem = new Filesystem(); $templates = array(); foreach ($this->finder->findAllTemplates() as $template) { // [snip] } // [snip] $this->writeCacheFile($cacheDir.’/templates.php', // [snip] }

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Customize! • You have full access to services, the container in ready • Create custom caches your application needs • Prefetch and cache data from external sources