Into the kernel and back

A journey into the heart of the Symfony framework, explaining internals of the application and http kernels, including the rich event ecosystem.

Discover almost unlimited possibilities that come with the framework out of the box, and can be used to extend its default request handling.

Finally, learn how to leverage the kernel and the event dispatcher to migrate away from an Old School PHP Spaghetti Project™ to a modern Symfony based application.

http://www.symfonyday.pt/2014/

Transcript

1. Into the kernel and back Jakub Zalas Lisbon, 8.03.2014
2. Olá! I work @SensioLabsUK I tweet @jakub_zalas I code @jakzal
3. HttpKernelInterface
4. namespace Symfony\Component\HttpKernel; use Symfony\Component\HttpFoundation\Request; use Symfony\Component\HttpFoundation\Response; interface HttpKernelInterface { const MASTER_REQUEST = 1; const SUB_REQUEST = 2; /** * @return Response */ public function handle( Request $request, $type = self::MASTER_REQUEST, $catch = true ); }
5. namespace Symfony\Component\HttpKernel; use Symfony\Component\HttpFoundation\Request; use Symfony\Component\HttpFoundation\Response; interface HttpKernelInterface { const MASTER_REQUEST = 1; const SUB_REQUEST = 2; /** * @return Response */ public function handle( Request $request, $type = self::MASTER_REQUEST, $catch = true ); }
6. Request Response /hello/sfdaypt
7. $response = $kernel->handle($request);
8. use Symfony\Component\HttpFoundation\Request; $request = Request::createFromGlobals(); $kernel = new SimpleKernel(); $response = $kernel->handle($request); $response->send();
9. use Symfony\Component\HttpKernel\HttpKernelInterface; use Symfony\Component\HttpFoundation\Request; use Symfony\Component\HttpFoundation\Response; class SimpleKernel implements HttpKernelInterface { public function handle(Request $request /*,...*/) { return new Response('Hello Portugal'); } }
10. use Symfony\Component\HttpKernel\HttpKernelInterface; use Symfony\Component\HttpFoundation\Request; use Symfony\Component\HttpFoundation\Response; class SimpleKernel implements HttpKernelInterface { public function handle(Request $request /*,...*/) { return new Response('Hello Portugal'); } }
11. Routing
12. Request Response callable   callable   callable   callable   / /hello/{name} /contact /events Router /hello/sfdaypt
13. public function handle(Request $request /*,...*/) { $controller = $this->matchRequest($request); $response = call_user_func($controller): return $response; } private function matchRequest(Request $request) { $map = array( '/' => array(new Homepage(), 'indexAction'), '/contact' => array(new Contact(), 'formAction') ); return $map[$request->getPathInfo()]; }
14. public function handle(Request $request /*,...*/) { $controller = $this->matchRequest($request); $response = call_user_func($controller): return $response; } private function matchRequest(Request $request) { $map = array( '/' => array(new Homepage(), 'indexAction'), '/contact' => array(new Contact(), 'formAction') ); return $map[$request->getPathInfo()]; }
15. private function matchRequest(Request $request) { $routes = $this->getRoutes(); $context = new RequestContext(); $context->fromRequest($request); $urlMatcher = new UrlMatcher($routes, $context); return $urlMatcher->matchRequest($request); } private function getRoutes() { $routes = new RouteCollection(); $routes->add('homepage', new Route('/', array('_controller' => 'Homepage::indexAction'))); $routes->add('contact', new Route('/', array('_controller' => 'Contact::formAction'))); return $routes; }
16. private function matchRequest(Request $request) { $routes = $this->getRoutes(); $context = new RequestContext(); $context->fromRequest($request); $urlMatcher = new UrlMatcher($routes, $context); return $urlMatcher->matchRequest($request); } private function getRoutes() { $routes = new RouteCollection(); $routes->add('homepage', new Route('/', array('_controller' => 'Homepage::indexAction'))); $routes->add('contact', new Route('/', array('_controller' => 'Contact::formAction'))); return $routes; }
17. private function matchRequest(Request $request) { $routes = $this->getRoutes(); $context = new RequestContext(); $context->fromRequest($request); $urlMatcher = new UrlMatcher($routes, $context); return $urlMatcher->matchRequest($request); } private function getRoutes() { $routes = new RouteCollection(); $routes->add('homepage', new Route('/', array('_controller' => 'Homepage::indexAction'))); $routes->add('contact', new Route('/', array('_controller' => 'Contact::formAction'))); return $routes; }
18. hello: path: /hello/{name} defaults: _controller: 'DemoController::helloAction'
19. private function getRoutes() { $locator = new FileLocator(array(__DIR__)); $loader = new YamlFileLoader($locator); $routes = $loader->load('routes.yml'); return $routes; }
20. public function handle(Request $request /*,...*/) { // ['_controller' => 'Homepage::indexAction'] $parameters = $this->matchRequest($request); // [new Homepage(), 'indexAction'] $controller = ??? $response = call_user_func($controller): return $response; }
21. Controller resolver
22. Request Response callable   callable   callable   callable   / /hello/{name} /contact /events Router /hello/sfdaypt Controller Resolver
23. public function handle(Request $request /*,...*/) { $parameters = $this->matchRequest($request); $controller = $this->resolveController($parameters); $response = call_user_func($controller): return $response; } private function resolveController($parameters) { // i.e. Homepage::indexAction $controller = $parameters['_controller']; list($class, $method) = explode('::', $controller); $controller = new $class(); return array($class, $method); }
24. public function handle(Request $request /*,...*/) { $parameters = $this->matchRequest($request); $controller = $this->resolveController($parameters); $response = call_user_func($controller): return $response; } private function resolveController($parameters) { // i.e. Homepage::indexAction $controller = $parameters['_controller']; list($class, $method) = explode('::', $controller); $controller = new $class(); return array($class, $method); }
25. public function handle(Request $request /*,...*/) { $parameters = $this->matchRequest($request); $controller = $this->resolveController($parameters); $response = call_user_func($controller): return $response; } private function resolveController($parameters) { // i.e. Homepage::indexAction $controller = $parameters['_controller']; list($class, $method) = explode('::', $controller); $controller = new $class(); return array($class, $method); }
26. use Symfony\Component\Routing\Matcher\RequestMatcherInterface; use Symfony\Component\HttpKernel\Controller\ControllerResolverInterface; public function __construct( RequestMatcherInterface $matcher, ControllerResolverInterface $resolver ) { $this->matcher = $matcher; $this->resolver = $resolver; }
27. public function handle(Request $request /*,...*/) { $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); $controller = $this->resolver->resolve($request); $response = call_user_func($controller): return $response; }
28. public function handle(Request $request /*,...*/) { $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); $controller = $this->resolver->resolve($request); $response = call_user_func($controller): return $response; }
29. EventDispatcherInterface
30. Handle Request Execute  a   controller   Geoip  lookup   Mobile   redirect   Authen6cate   ?   ?   Add     debug  to   response   ?   Match  a   request  
31. Request Response Router Controller Resolver Event Dispatcher GeoipListener SessionListener LocaleListener Firewall kernel.request TemplateListener ControllerListener ParamConverter Listener TemplateListener
32. Request Response Router Controller Resolver Event Dispatcher GeoipListener SessionListener LocaleListener Firewall kernel.request TemplateListener ControllerListener ParamConverter Listener TemplateListener
33. use Symfony\Component\EventDispatcher\EventDispatcherInterface; use Symfony\Component\Routing\Matcher\RequestMatcherInterface; use Symfony\Component\HttpKernel\Controller\ControllerResolverInterface; public function __construct( EventDispatcherInterface $dispatcher, RequestMatcherInterface $matcher, ControllerResolverInterface $resolver ) { $this->eventDispatcher = $dispatcher; $this->matcher = $matcher; $this->resolver = $resolver; }
34. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); $controller = $this->resolver->resolve($request); $response = call_user_func($controller): return $response; }
35. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); $controller = $this->resolver->resolve($request); $response = call_user_func($controller): return $response; }
36. Request Response Router Controller Resolver Event Dispatcher GeoipListener SessionListener LocaleListener Firewall kernel.request
37. Request Response Controller Resolver Event Dispatcher kernel.request GeoipListener SessionListener LocaleListener RouterListener Firewall
38. use Symfony\Component\EventDispatcher\EventDispatcherInterface; use Symfony\Component\HttpKernel\Controller\ControllerResolverInterface; public function __construct( EventDispatcherInterface $dispatcher, ControllerResolverInterface $resolver ) { $this->eventDispatcher = $dispatcher; $this->resolver = $resolver; }
39. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); $controller = $this->resolver->resolve($request); $response = call_user_func($controller): return $response; }
40. class RouterListener { public function __construct( RequestMatcherInterface $matcher ) { $this->matcher = $matcher } function onKernelRequest(GetResponseEvent $event) { // ... } }
41. // RouterListener public function onKernelRequest(GetResponseEvent $event) { $request = $event->getRequest(); if ($request->attributes->has('_controller')) { // routing is already done return; } $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); }
42. // RouterListener public function onKernelRequest(GetResponseEvent $event) { $request = $event->getRequest(); if ($request->attributes->has('_controller')) { // routing is already done return; } $parameters = $this->matcher->matchRequest($request); $request->attributes->add($parameters); }
43. Request Response Controller Resolver Event Dispatcher kernel.request GeoipListener SessionListener LocaleListener RouterListener Firewall
44. Request Response Controller Resolver Event Dispatcher kernel.request GeoipListener SessionListener LocaleListener RouterListener Firewall
45. // RedirectListener public function onKernelRequest(GetResponseEvent $event) { $event->setResponse( new RedirectResponse('http://www.symfonyday.pt/') ); }
46. // HttpKernel public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); if ($event->hasResponse()) { return $event->getResponse(); } $controller = $this->resolver->resolve($request); $response = call_user_func($controller); return $response; }
47. Request Response Controller Resolver Event Dispatcher kernel.response CacheListener ResponseListener ProfilerListener WebDebugToolbar Listener
48. Request Response Controller Resolver Event Dispatcher kernel.finish_request LocaleListener RouterListener Firewall
49. Request Response Controller Resolver Event Dispatcher kernel.finish_request LocaleListener RouterListener Firewall
50. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); if ($event->hasResponse()) { return $this->filterResponse($event->getResponse(), $request, $type); } $controller = $this->resolver->resolve($request); $response = call_user_func($controller); return $this->filterResponse($response, $request, $type); } private function filterResponse(Response $response, Request $request, $type) { $event = new FilterResponseEvent( $this, $request, $type, $response ); $this->dispatcher->dispatch('kernel.response', $event); $response = $event->getResponse(); $event = new FinishRequestEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.finish_request', $event); return $response; }
51. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); if ($event->hasResponse()) { return $this->filterResponse($event->getResponse(), $request, $type); } $controller = $this->resolver->resolve($request); $response = call_user_func($controller); return $this->filterResponse($response, $request, $type); } private function filterResponse(Response $response, Request $request, $type) { $event = new FilterResponseEvent( $this, $request, $type, $response ); $this->dispatcher->dispatch('kernel.response', $event); $response = $event->getResponse(); $event = new FinishRequestEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.finish_request', $event); return $response; }
52. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); if ($event->hasResponse()) { return $this->filterResponse($event->getResponse(), $request, $type); } $controller = $this->resolver->resolve($request); $response = call_user_func($controller); return $this->filterResponse($response, $request, $type); } private function filterResponse(Response $response, Response $response, $type) { $event = new FilterResponseEvent( $this, $request, $type, $response ); $this->dispatcher->dispatch('kernel.response', $event); $response = $event->getResponse(); $event = new FinishRequestEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.finish_request', $event); return $response; }
53. public function handle(Request $request, $type, $catch) { $event = new GetResponseEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.request', $event); if ($event->hasResponse()) { return $this->filterResponse($event->getResponse(), $request, $type); } $controller = $this->resolver->resolve($request); $response = call_user_func($controller); return $this->filterResponse($response, $request, $type); } private function filterResponse(Response $response, Response $response, $type) { $event = new FilterResponseEvent( $this, $request, $type, $response ); $this->dispatcher->dispatch('kernel.response', $event); $response = $event->getResponse(); $event = new FinishRequestEvent($this, $request, $type); $this->dispatcher->dispatch('kernel.finish_request', $event); return $response; }
54. Request Response Controller Resolver Event Dispatcher ControllerListener kernel.controller RequestDataCollector Listener ParamConverter Listener TemplateListener
55. public function handle(Request $request, $type, $catch) { // ... $controller = $this->resolver->resolve($request); $event = new FilterControllerEvent( $this, $controller, $request, $type ); $this->dispatcher->dispatch( 'kernel.controller', $event ); $controller = $event->getController(); $response = call_user_func($controller); return $this->filterResponse($response, $request, $type); }
56. public function handle(Request $request, $type, $catch) { // ... $controller = $this->resolver->resolve($request); $event = new FilterControllerEvent( $this, $controller, $request, $type ); $this->dispatcher->dispatch( 'kernel.controller', $event ); $controller = $event->getController(); $response = call_user_func($controller); return $this->filterResponse($response, $request, $type); }
57. public function handle(Request $request, $type, $catch) { // ... $controller = $this->resolver->resolve($request); $event = new FilterControllerEvent( $this, $controller, $request, $type ); $this->dispatcher->dispatch('kernel.controller', $event); $controller = $event->getController(); $arguments = $this->resolver->getArguments( $request, $controller ); $response = call_user_func($controller, $arguments); return $this->filterResponse($response, $request, $type); }
58. Request Response Controller Resolver Event Dispatcher TemplateListener kernel.view
59. public function handle(Request $request, $type, $catch) { // ... $response = call_user_func($controller, $arguments); if (!$response instance of Response) { $event = new GetResponseForControllerResultEvent( $this, $request, $type, $response ); $this->dispatcher->dispatch( 'kernel.view', $event ); $response = $event->getResponse(); } return $this->filterResponse($response, $request, $type); }
60. public function handle(Request $request, $type, $catch) { // ... $response = call_user_func($controller, $arguments); if (!$response instance of Response) { $event = new GetResponseForControllerResultEvent( $this, $request, $type, $response ); $this->dispatcher->dispatch( 'kernel.view', $event ); $response = $event->getResponse(); } return $this->filterResponse($response, $request, $type); }
61. Build-in events
62. The usual path
63. Request Response Controller Resolver Event Dispatcher kernel.request FragmentListener SessionListener LocaleListener RouterListener Firewall
64. Request Response Controller Resolver Event Dispatcher ControllerListener kernel.controller RequestDataCollector Listener ParamConverter Listener TemplateListener
65. Request Response Controller Resolver Event Dispatcher kernel.response CacheListener ResponseListener ProfilerListener WebDebugToolbar Listener
66. Request Response Controller Resolver Event Dispatcher kernel.finish_request LocaleListener RouterListener Firewall
67. Request Response Controller Resolver Event Dispatcher TemplateListener kernel.view
68. Request Response Controller Resolver Event Dispatcher kernel.terminate ProfilerListener EmailSenderListener
69. A Response set during kernel.request
70. Request Response Controller Resolver Event Dispatcher kernel.request FragmentListener SessionListener LocaleListener RouterListener Firewall
71. Request Response Controller Resolver Event Dispatcher kernel.response CacheListener ResponseListener ProfilerListener WebDebugToolbar Listener
72. Request Response Controller Resolver Event Dispatcher kernel.finish_request LocaleListener RouterListener Firewall
73. Request Response Controller Resolver Event Dispatcher kernel.finish_request LocaleListener RouterListener Firewall
74. Request Response Controller Resolver Event Dispatcher kernel.terminate TraceableEvent Dispatcher ProfilerListener EmailSenderListener
75. An exception thrown during handling a request
76. Request Response Controller Resolver Event Dispatcher kernel.request FragmentListener SessionListener LocaleListener RouterListener Firewall
77. Request Response Controller Resolver Event Dispatcher ExceptionListener AccessDeniedListener ProfilerListener kernel.exception
78. Symfony\Component\HttpKernel\HttpKernel Read more...
79. KernelInterface
80. interface KernelInterface extends HttpKernelInterface, \Serializable { public function registerBundles(); public function registerContainerConfiguration( LoaderInterface $loader); public function boot(); public function shutdown(); public function getBundles(); public function isClassInActiveBundle($class); public function getBundle($name, $first = true); public function locateResource($name, $dir = null, $first = true); public function getName(); public function getEnvironment(); public function isDebug(); public function getRootDir(); public function getContainer(); public function getStartTime(); public function getCacheDir(); public function getLogDir(); public function getCharset(); }
81. H<p   Kernel   App  Kernel   Request Response
82. H<p   Kernel   App  Kernel   Request Response App  Cache  
83. class Kernel implements KernelInterface { public function handle( Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true) ) { if (false === $this->booted) { $this->boot(); } return $this->container->get('http_kernel') ->handle($request, $type, $catch); } }
84. class Kernel implements KernelInterface { public function handle( Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true) ) { if (false === $this->booted) { $this->boot(); } return $this->container->get('http_kernel') ->handle($request, $type, $catch); } }
85. class Kernel implements KernelInterface { public function handle( Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true) ) { if (false === $this->booted) { $this->boot(); } return $this->container->get('http_kernel') ->handle($request, $type, $catch); } }
86. public function boot() { $this->initializeBundles(); $this->initializeContainer(); foreach ($this->getBundles() as $bundle) { $bundle->setContainer($this->container); $bundle->boot(); } $this->booted = true; }
87. protected function initializeContainer() { // ... if (!$cache->isFresh()) { $container = $this->buildContainer(); $container->compile(); $this->dumpContainer($cache, $container/*…*/); } require_once $cache; $this->container = new $class(); $this->container->set('kernel', $this); // ... }
88. protected function initializeContainer() { // ... if (!$cache->isFresh()) { $container = $this->buildContainer(); $container->compile(); $this->dumpContainer($cache, $container/*…*/); } require_once $cache; $this->container = new $class(); $this->container->set('kernel', $this); // ... }
89. class appDevDebugProjectContainer extends Container { // ... protected function getLoggerService() { $this->services['logger'] = $instance = new \Symfony\Bridge\Monolog\Logger('app'); $instance->pushHandler($this->get('monolog.handler.console')); $instance->pushHandler($this->get('monolog.handler.main')); $instance->pushHandler($this->get('monolog.handler.debug')); return $instance; } // ... }
90. protected function initializeContainer() { // ... if (!$cache->isFresh()) { $container = $this->buildContainer(); $container->compile(); $this->dumpContainer($cache, $container/*…*/); } require_once $cache; $this->container = new $class(); $this->container->set('kernel', $this); // ... }
91. protected function initializeContainer() { // ... if (!$cache->isFresh()) { $container = $this->buildContainer(); $container->compile(); $this->dumpContainer($cache, $container/*…*/); } require_once $cache; $this->container = new $class(); $this->container->set('kernel', $this); // ... }
92. Container and events in a legacy application
93. $kernel = new \AppKernel('dev', true); $kernel->boot(); $request = Request::createFromGlobals(); $request->attributes->set('is_legacy', true); $container = $kernel->getContainer(); $container->enterScope('request'); $container->get('request_stack')->push($request); $event = new GetResponseEvent( $kernel, $request, HttpKernelInterface::MASTER_REQUEST ); $container->get('event_dispatcher'); ->dispatch('kernel.request', $event);
94. $kernel = new \AppKernel('dev', true); $kernel->boot(); $request = Request::createFromGlobals(); $request->attributes->set('is_legacy', true); $container = $kernel->getContainer(); $container->enterScope('request'); $container->get('request_stack')->push($request); $event = new GetResponseEvent( $kernel, $request, HttpKernelInterface::MASTER_REQUEST ); $container->get('event_dispatcher'); ->dispatch('kernel.request', $event);
95. $kernel = new \AppKernel('dev', true); $kernel->boot(); $request = Request::createFromGlobals(); $request->attributes->set('is_legacy', true); $container = $kernel->getContainer(); $container->enterScope('request'); $container->get('request_stack')->push($request); $event = new GetResponseEvent( $kernel, $request, HttpKernelInterface::MASTER_REQUEST ); $container->get('event_dispatcher'); ->dispatch('kernel.request', $event);
96. $kernel = new \AppKernel('dev', true); $kernel->boot(); $request = Request::createFromGlobals(); $request->attributes->set('is_legacy', true); $container = $kernel->getContainer(); $container->enterScope('request'); $container->get('request_stack')->push($request); $event = new GetResponseEvent( $kernel, $request, HttpKernelInterface::MASTER_REQUEST ); $container->get('event_dispatcher'); ->dispatch('kernel.request', $event);
97. $kernel = new \AppKernel('dev', true); $kernel->boot(); $request = Request::createFromGlobals(); $request->attributes->set('is_legacy', true); $container = $kernel->getContainer(); $container->enterScope('request'); $container->get('request_stack')->push($request); $event = new GetResponseEvent( $kernel, $request, HttpKernelInterface::MASTER_REQUEST ); $container->get('event_dispatcher'); ->dispatch('kernel.request', $event);
98. class RouterListener extends BaseRouterListener { public function onKernelRequest( GetResponseEvent $event ) { $request = $event->getRequest(); try { parent::onKernelRequest($event); } catch (NotFoundHttpException $e) { if (!$request->attributes->get('is_legacy')) { throw $e; } } } }
99. Thank you! https://joind.in/10782