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
   

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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!!!
   

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3. Act 1
   I feel like making a page!
   @weaverryan
   

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4. Module
   Route
   Controller
   @weaverryan
   !
   !
   !
   

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5. @weaverryan
   name: Dino ROAR

   type: module

   description: "ROOOOOAR AT YOU!"

   package: Sample

   core: 8.x
   

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6. @weaverryan
   drush pm-enable dino_roar
   

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7. Module
   Route
   Controller
   @weaverryan
   !
   !
   "
   

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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???
   

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9. Module
   Route
   Controller
   @weaverryan
   !
   "
   "
   

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10. @weaverryan
    

    namespace Drupal\dino_roar\Controller;

    

    use Symfony\Component\HttpFoundation\Response;

    

    class RoarController

    {

    public function roar()

    {

    return new Response('ROOOOAR');

    }

    }
    

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11. Module
    Route
    Controller
    @weaverryan
    "
    "
    "
    

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12. @weaverryan
    

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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
    

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14. @weaverryan
    dino_says:

    path: /the/dino/says/{count}

    defaults:

    _controller: Drupal\dino_roar\Controller\RoarController::roar

    requirements:

    _permission: 'access content'
    

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15. @weaverryan
    class RoarController

    {

    public function roar($count)

    {

    $roar = 'R'.str_repeat('O', $count).'AR';

    return new Response($roar);

    }

    }
    

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16. Act 2
    Our Debugging Arsenal
    @weaverryan
    

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17. Every page has
    a route &
    controller
    @weaverryan
    

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18. Can we get a
    list of all routes?
    @weaverryan
    

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20. @weaverryan
    

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21. @weaverryan
    

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22. Can I get this
    right on the web?
    @weaverryan
    

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23. Say THANKS!
    

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24. Install that module!
    download 2 JS files
    Download it!
    @weaverryan
    

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25. @weaverryan
    

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26. View Slide

27. View Slide

28. For a good time, click
    all the pretty checkboxes
    

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33. How does the
    /admin/structure
    page work?
    @weaverryan
    

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35. Act 3
    Services and the
    “container”
    @weaverryan
    

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36. Services == Useful Objects
    @weaverryan
    

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37. The container == the object
    that contains all the services
    @weaverryan
    

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38. In Drupal 8
    The container is pre-loaded
    with many useful services
    (objects)
    

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39. … a short list of 485 …
    

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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%']
    

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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
    

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42. Act 4
    Events
    @weaverryan
    

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43. Just like “hooks”,
    D8 has events
    @weaverryan
    

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44. “Hi! When event XXXXX
    happens, execute this
    function. kthxbai”
    YOU CAN TELL D8
    @weaverryan
    

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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!
    

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47. Act 5
    Request attributes
    @weaverryan
    

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48. @weaverryan
    

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49. @weaverryan
    

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50. @weaverryan
    dino_says:

    path: /the/dino/says/{count}

    defaults:

    _controller: Drupal\dino_roar\Controller\RoarController::roar

    requirements:

    _permission: 'access content'
    

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51. @weaverryan
    class RoarController

    {

    public function roar($count)

    {

    $roar = 'R'.str_repeat('O', $count).'AR';

    return new Response($roar);

    }

    }
    

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52. @weaverryan
    class RoarController

    {

    public function roar($_route, $_access_result)

    {

    $roar = 'R'.str_repeat('O', $count).'AR';

    return new Response($roar);

    }

    }
    

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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);

    }

    }
    

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54. @weaverryan
    

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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!
    

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56. Act 6
    Up-casting nodes
    @weaverryan
    

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57. @weaverryan
    alternate_node_view:

    path: /the/dino/{node}

    defaults:

    _controller: Drupal\dino_roar\Controller\RoarController::node

    requirements:

    _permission: 'access content'
    

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58. @weaverryan
    class RoarController

    {

    public function node($node)

    {

    return new Response('The node is '.$node);

    }

    }
    #
    

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59. @weaverryan
    

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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
    

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61. @weaverryan
    public function node($node)

    {

    return new Response(‘node '.$node->getTitle());

    }
    

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62. @weaverryan
    

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63. paramconverter
    @weaverryan
    

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64. @weaverryan
    services:

    paramconverter.entity:

    class: Drupal\Core\ParamConverter\EntityConverter

    tags:

    - { name: paramconverter }

    arguments: ['@entity.manager']
    

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65. @weaverryan
    interface ParamConverterInterface {

    

    public function convert($value, $definition, $name, array $defaults);

    

    public function applies($definition, $name, Route $route);

    

    }
    

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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
    

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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!
    

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68. @weaverryan
    alternate_node_view:

    path: /the/dino/{node}

    defaults:

    _controller: Drupal\dino_roar\Controller\RoarController::node

    requirements:

    _permission: 'access content'
    

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69. @weaverryan
    class RoarController

    {

    public function node(EntityInterface $node)

    {

    return new Response('The node '.$node->getTitle());

    }

    }
    

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70. Act 7
    The render array
    @weaverryan
    

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71. @weaverryan
    class RoarController

    {

    public function node(Node $node)

    {

    return [

    '#title' => $node->getTitle()

    ];

    }

    }
    

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72. @weaverryan
    THIS SHOULD NOT WORK…
    

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73. @weaverryan
    Who created the Response?
    

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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
    

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75. @weaverryan
    the kernel.view event
    MainContentViewSubscriber
    

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76. render.main_content_renderer
    @weaverryan
    Turn my “array” into a
    Response for some format
    

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77. @weaverryan
    services:

    main_content_renderer.html:

    class: Drupal\Core\Render\MainContent\HtmlRenderer

    arguments: ['@title_resolver', '...' ]

    tags:

    - { name: render.main_content_renderer, format: html }
    

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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;

    }

    }
    

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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!
    

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80. Act 8
    Question Everything
    @weaverryan
    

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81. @weaverryan
    some_route:

    path: /building/a/page

    defaults:

    _form: Drupal\dino_roar\Form\SomeForm

    requirements:

    _permission: 'access content'
    Where’s my _controller?
    

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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
    

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83. DIG DEEP
    You have the tools
    @weaverryan
    

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84. View Slide

85. View Slide

86. WEBPROFILER: EVENTS
    

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87. WEBPROFILER: TIMELINE
    

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88. WEBPROFILER: SERVICES
    

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89. @weaverryan
    WEBPROFILER: REQUEST
    

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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%']
    

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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!
    

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92. Ryan Weaver
    @weaverryan
    THANK YOU!
    http://DrupalConsole.org
    http://bit.ly/drupal-webprofiler
    @jmolivas @lussoluca
    

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