DrupalCon 2015: Routes, controllers and responses: The Basic Lifecycle of a D8 Request

Whether your viewing a node on the frontend, consuming a JSON endpoint or using the admin interface, every request in D8 follows the same workflow: routing, a controller and a response. Woh!

In this talk, we'll uncover the basic lifecycle of a D8 request, by creating a custom page using routes, a controller and a response. And you'll see just how simple life is. Once we're there, we'll dive deeper to see how Drupal uses this *exact* same stuff to fuel node pages, the admin interface and everything else. If you want to be able to create custom pages or open up the hood and really "get" D8, this is your first step.

Transcript

1. routes, controllers and responses: THE BASIC LIFECYCLE OF A D8 REQUEST
2. > Husband of the much more talented @leannapelham knplabs.com twitter.com/weaverryan Hallo! > Lead contributor to the Symfony documentation
 > KnpLabs US - Symfony consulting, training & kumbaya > Writer for KnpUniversity.com awesome amazing PHP Tutorials!!!
3. Act 1 I feel like making a page! @weaverryan
4. Module Route Controller @weaverryan ! ! !
5. @weaverryan name: Dino ROAR
 type: module
 description: "ROOOOOAR AT YOU!"
 package: Sample
 core: 8.x
6. @weaverryan drush pm-enable dino_roar
7. Module Route Controller @weaverryan ! ! "
8. @weaverryan dino_says:
 path: /the/dino/says
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::roar
 requirements:
 _permission: 'access content' hook_menu anyone? page callback???
9. Module Route Controller @weaverryan ! " "
10. @weaverryan <?php
 
 namespace Drupal\dino_roar\Controller;
 
 use Symfony\Component\HttpFoundation\Response;
 
 class RoarController
 {
 public function roar()
 {
 return new Response('ROOOOAR');
 }
 }
11. Module Route Controller @weaverryan " " "
12. @weaverryan
13. Request -> Response Framework Response: ROOOAR! Routing: Determine a function that can create this page (the controller) Request: GET /the/dino/says The Controller: Our code: constructs the page @weaverryan
14. @weaverryan dino_says:
 path: /the/dino/says/{count}
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::roar
 requirements:
 _permission: 'access content'
15. @weaverryan class RoarController
 {
 public function roar($count)
 {
 $roar = 'R'.str_repeat('O', $count).'AR';
 return new Response($roar);
 }
 }
16. Act 2 Our Debugging Arsenal @weaverryan
17. Every page has a route & controller @weaverryan
18. Can we get a list of all routes? @weaverryan
20. @weaverryan
21. @weaverryan
22. Can I get this right on the web? @weaverryan
23. Say THANKS!
24. Install that module! download 2 JS files Download it! @weaverryan
25. @weaverryan
28. For a good time, click all the pretty checkboxes
33. How does the /admin/structure page work? @weaverryan
35. Act 3 Services and the “container” @weaverryan
36. Services == Useful Objects @weaverryan
37. The container == the object that contains all the services @weaverryan
38. In Drupal 8 The container is pre-loaded with many useful services (objects)
39. … a short list of 485 …
40. @weaverryan parameters:
 factory.keyvalue:
 default: keyvalue.database
 services:
 state:
 class: Drupal\Core\State\State
 arguments: ['@keyvalue']
 keyvalue:
 class: Drupal\Core\KeyValueStore\KeyValueFactory
 arguments: ['@service_container', '%factory.keyvalue%']
41. Request -> Response Framework The Controller: Our code: constructs the page Response: Hello Drupal! Container (with services) Routing: Determine a function that can create this page (the controller) Request: GET /hello/Drupal! @weaverryan
42. Act 4 Events @weaverryan
43. Just like “hooks”, D8 has events @weaverryan
44. “Hi! When event XXXXX happens, execute this function. kthxbai” YOU CAN TELL D8 @weaverryan
45. EVENTS kernel.view kernel.response Request -> Response Framework The Controller: Our code: constructs the page Container (with services) EVENT kernel.controller Response: Hello Drupal! Routing: Determine a function that can create this page (the controller) EVENT kernel.request @weaverryan Request: GET /hello/Drupal!
47. Act 5 Request attributes @weaverryan
48. @weaverryan
49. @weaverryan
50. @weaverryan dino_says:
 path: /the/dino/says/{count}
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::roar
 requirements:
 _permission: 'access content'
51. @weaverryan class RoarController
 {
 public function roar($count)
 {
 $roar = 'R'.str_repeat('O', $count).'AR';
 return new Response($roar);
 }
 }
52. @weaverryan class RoarController
 {
 public function roar($_route, $_access_result)
 {
 $roar = 'R'.str_repeat('O', $count).'AR';
 return new Response($roar);
 }
 }
53. @weaverryan use Symfony\Component\HttpFoundation\Request;
 
 class RoarController
 {
 public function roar(Request $request)
 {
 $count = $request->attributes->get('count'); 
 $roar = 'R'.str_repeat('O', $count).'AR';
 return new Response($roar);
 }
 }
54. @weaverryan
55. EVENTS kernel.view kernel.response Request -> Response Framework The Controller: Our code: constructs the page Container (with services) EVENT kernel.controller Response: Hello Drupal! Routing: Determine a function that can create this page (the controller) EVENT kernel.request @weaverryan Arguments $request->attributes Request: GET /hello/Drupal!
56. Act 6 Up-casting nodes @weaverryan
57. @weaverryan alternate_node_view:
 path: /the/dino/{node}
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::node
 requirements:
 _permission: 'access content'
58. @weaverryan class RoarController
 {
 public function node($node)
 {
 return new Response('The node is '.$node);
 }
 } #
59. @weaverryan
60. @weaverryan alternate_node_view:
 path: /the/dino/{node}
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::node
 requirements:
 _permission: 'access content'
 options:
 parameters:
 node:
 type: entity:node
61. @weaverryan public function node($node)
 {
 return new Response(‘node '.$node->getTitle());
 }
62. @weaverryan
63. paramconverter @weaverryan
64. @weaverryan services:
 paramconverter.entity:
 class: Drupal\Core\ParamConverter\EntityConverter
 tags:
 - { name: paramconverter }
 arguments: ['@entity.manager']
65. @weaverryan interface ParamConverterInterface {
 
 public function convert($value, $definition, $name, array $defaults);
 
 public function applies($definition, $name, Route $route);
 
 }
66. @weaverryan interface ParamConverterInterface {
 
 public function convert($value, $definition, $name, array $defaults);
 
 public function applies($definition, $name, Route $route);
 
 } alternate_node_view:
 path: /the/dino/{node}
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::node
 requirements:
 _permission: 'access content'
 options:
 parameters:
 node:
 type: entity:node
67. EVENTS kernel.view kernel.response Request -> Response Framework The Controller: Our code: constructs the page Container (with services) EVENT kernel.controller Response: Hello Drupal! Routing: Determine a function that can create this page (the controller) EVENT kernel.request @weaverryan Arguments $request->attributes paramconverters Request: GET /hello/Drupal!
68. @weaverryan alternate_node_view:
 path: /the/dino/{node}
 defaults:
 _controller: Drupal\dino_roar\Controller\RoarController::node
 requirements:
 _permission: 'access content'
69. @weaverryan class RoarController
 {
 public function node(EntityInterface $node)
 {
 return new Response('The node '.$node->getTitle());
 }
 }
70. Act 7 The render array @weaverryan
71. @weaverryan class RoarController
 {
 public function node(Node $node)
 {
 return [
 '#title' => $node->getTitle()
 ];
 }
 }
72. @weaverryan THIS SHOULD NOT WORK…
73. @weaverryan Who created the Response?
74. EVENTS kernel.view kernel.response Request -> Response Framework The Controller: Our code: constructs the page Container (with services) EVENT kernel.controller Response: Hello Drupal! Routing: Determine a function that can create this page (the controller) Request: GET /hello/Drupal! EVENT kernel.request @weaverryan Arguments $request->attributes paramconverters
75. @weaverryan the kernel.view event MainContentViewSubscriber
76. render.main_content_renderer @weaverryan Turn my “array” into a Response for some format
77. @weaverryan services:
 main_content_renderer.html:
 class: Drupal\Core\Render\MainContent\HtmlRenderer
 arguments: ['@title_resolver', '...' ]
 tags:
 - { name: render.main_content_renderer, format: html }
78. class HtmlRenderer implements MainContentRendererInterface { public function renderResponse(array $main_content, Reques // ...
 $this->buildPageTopAndBottom($html);
 
 // ...
 $content = $this->renderer->render($html);
 
 $response = new CacheableResponse($content, 200,[
 'Content-Type' => 'text/html; charset=UTF-8',
 ]);
 
 return $response;
 }
 }
79. EVENTS kernel.view kernel.response Request -> Response Framework The Controller: Our code: constructs the page Container (with services) EVENT kernel.controller Response: Hello Drupal! Routing: Determine a function that can create this page (the controller) EVENT kernel.request @weaverryan Arguments $request->attributes paramconverters “content renderers” Request: GET /hello/Drupal!
80. Act 8 Question Everything @weaverryan
81. @weaverryan some_route:
 path: /building/a/page
 defaults:
 _form: Drupal\dino_roar\Form\SomeForm
 requirements:
 _permission: 'access content' Where’s my _controller?
82. @weaverryan class ContentControllerSubscriber implements EventSubscr public function onRequestDeriveFormWrapper(GetResponse $request = $event->getRequest();
 
 if ($request->attributes->has('_form')) {
 $request->attributes->set(
 '_controller',
 'controller.form:getContentResult'
 );
 }
 }
 } $ Oh, it’s in this listener
83. DIG DEEP You have the tools @weaverryan
86. WEBPROFILER: EVENTS
87. WEBPROFILER: TIMELINE
88. WEBPROFILER: SERVICES
89. @weaverryan WEBPROFILER: REQUEST
90. @weaverryan parameters:
 factory.keyvalue:
 default: keyvalue.database
 services:
 state:
 class: Drupal\Core\State\State
 arguments: ['@keyvalue']
 keyvalue:
 class: Drupal\Core\KeyValueStore\KeyValueFactory
 arguments: ['@service_container', '%factory.keyvalue%']
91. EVENTS kernel.view kernel.response Request -> Response Framework The Controller: Our code: constructs the page Container (with services) EVENT kernel.controller Response: Hello Drupal! Routing: Determine a function that can create this page (the controller) EVENT kernel.request @weaverryan Arguments $request->attributes paramconverters “content renderers” Request: GET /hello/Drupal!
92. Ryan Weaver @weaverryan THANK YOU! http://DrupalConsole.org http://bit.ly/drupal-webprofiler @jmolivas @lussoluca