Palantir.net

Drupal 8

The Crash Course

Presented by Larry Garfield (@Crell)

@Crell

Senior Architect, Palantir.net
Drupal 8 Web Services Lead
Drupal Representative, PHP-FIG
Advisor, Drupal Association
Loveable pedant

https://github.com/palantirnet/hugs

Drupal 8 is so different,
how will I ever learn it?

—Drupal developers

I hear Drupal 8 is finally not weird,
does that mean I can learn it?

—Everyone else

The more things change,
the more they stay the same

The concepts are still Drupal

The achitecture is modernized

The APIs are more consistent

Just enough theory

PHP 4 architecture

HTTP Architecture

Symfony/HttpKernel architecture


interface HttpKernelInterface {
  const MASTER_REQUEST = 1;
  const SUB_REQUEST = 2;

  /**
   * Handles a Request to convert it to a Response.
   *
   * @param Request $request A Request instance
   * @param integer $type    The type of the request
   * @param Boolean $catch Whether to catch exceptions or not
   *
   * @return Response A Response instance
   */
  public function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true);
}

HttpKernel pipeline

Controllers

The concept formerly known as page callbacks
and now represented by a ()


use Symfony\Component\HttpFoundation\Response;

class MyControllers {

  public function hello() {
    return new Response('<html><body>Hello World</body></html>');
  }
}


use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\JsonResponse;

class MyControllers {

  public function hello() {
    return new Response('<html><body>Hello World</body></html>');
  }

  public function helloJson() {
    $data['Hello'] = 'World';
    return new JsonResponse($data);
  }
}


use Symfony\Component\HttpFoundation\StreamedResponse;

class MyControllers {

  public function helloCsv() {
    $lots_of_data = get_lots_of_data();

    $response = new StreamedResponse();
    $response->headers->set('Content-Type', 'text/csv');

    $response->setCallback(function() use ($lots_of_data) {
      foreach ($lots_of_data as $record) {
        print implode(', ', $record) . PHP_EOL;
      }
    });

    return $response;
  }
}


use Symfony\Component\HttpFoundation\BinaryFileResponse;

class MyControllers {

  public function privateFile() {
    return new BinaryFileResponse('secret_plans.odt');
  }
}


class MyControllers {

  public function helloDrupal() {
    return array(
      '#theme' => 'a_drupal_render_array',
      '#description' => 'Those still exist.',
    );
  }
}

/hello/world/{from}/{to}


use Symfony\Component\HttpFoundation\Request;

class HelloController {

  public function helloDrupal($to, $from, Request $request) {
    return array(
      '#theme' => 'love_letter',
      '#from' => $from,
      '#to' => $to,
    );
  }
}

module.routing.yml


hello.world:
  path: '/hello/world/{from}/{to}'
  defaults:
    _controller: '\Drupal\mymodule\Controller\HelloController::helloDrupal'
  requirements:
    _permission: 'access content'
    from: \s+
    to: \s+

Gah, enough theory, how do I do stuff?

Drupal in 2 steps:

Build a tool
Wire it up

Drupal in 2 (other) steps:

Extend a base class/interface
Tell Drupal about it

How do I...?

define a module

/modules/hugs/hugs.info.yml


name: Hugs
description: Examples of hugs
type: module
core: 8.x

The modules page, showing the hug module.

How do I...?

make a page

/modules/hugs/src/Controller/HugsController.php


namespace Drupal\hugs\Controller;

use Drupal\Core\Controller\ControllerBase;

class HugsController extends ControllerBase {

  public function hug($to, $from) {
    $message = $this->t('%from sends hugs to %to', [
      '%from' => $from,
      '%to' => $to,
    ]);

    return ['#markup' => $message];
  }
}

/modules/hugs/hugs.routing.yml


hugs.hug:
  path: /hug/{from}/{to}
  defaults:
    _controller: 'Drupal\hugs\Controller\HugsController::hug'
    _title: 'Hug!'
  requirements:
    _permission: 'access content'

How do I...?

make content themeable

/modules/hugs/hugs.module


function hugs_theme() {
  $theme['hug_page'] = [
    'variables' => ['from' => NULL, 'to' => NULL],
    'template' => 'hug_page',
  ];

  return $theme;
}

/modules/hugs/template/hug_page.html.twig


<section>
  {% trans %}
    <strong>{{ from }}</strong> hugs <em>{{ to }}</em>
  {% endtrans %}
</section>

/modules/hugs/src/Controller/HugsController


namespace Drupal\hugs\Controller;

use Drupal\Core\Controller\ControllerBase;

class HugsController extends ControllerBase {

  public function hug($to, $from) {
    return [
      '#theme' => 'hug_page',
      '#from' => $from,
      '#to' => $to,
    ];
  }
}

How do I...?

make a config form

/modules/hugs/config/install/hugs.settings.yml


default_count: 3

/modules/hugs/config/schema/hugs.settings.yml


hugs.settings:
  type: mapping
  label: 'Hug module settings'
  mapping:
    default_count:
      type: integer
      label: 'Default hug count'

/modules/hugs/src/Form/ConfigForm.php


namespace Drupal\hugs\Form;
use Drupal\Core\Form\ConfigFormBase;
use Drupal\Core\Form\FormStateInterface;

class ConfigForm extends ConfigFormBase {
  public function getFormId() { return 'hug_config'; }

  protected function getEditableConfigNames() {
    return ['hugs.settings'];
  }

  public function buildForm(array $form, FormStateInterface $form_state) {
    $config = $this->config('hugs.settings');

    $form['default_count'] = [
      '#type' => 'number',
      '#title' => $this->t('Default hug count'),
      '#default_value' => $config->get('default_count'),
    ];
    return parent::buildForm($form, $form_state);
  }

  public function submitForm(array &$form, FormStateInterface $form_state) {
    parent::submitForm($form, $form_state);
    $config = $this->config('hug.settings');
    $config->set('default_count', $form_state->getValue('default_count'));
    $config->save();
  }
}

/modules/hugs/hugs.routing.yml


hugs.config:
  path: /admin/config/system/hugs
  defaults:
    _form: 'Drupal\hugs\Form\ConfigForm'
    _title: 'Hug configuration'
  requirements:
    _permission: 'configure_hugs'

/modules/hugs/hugs.permissions.yml


configure_hugs:
  title: 'Configure the hugs system'
  description: 'Configure default hug count'

/modules/hugs/hugs.links.menu.yml


hugs.config:
  title: 'Hugs configuration'
  description: 'Configure the hugs system'
  route_name: hugs.config
  parent: system.admin_config_system

/modules/hugs/src/Controller/HugsController


namespace Drupal\hugs\Controller;

use Drupal\Core\Controller\ControllerBase;

class HugsController extends ControllerBase {

  public function hug($to, $from, $count) {
    if (!$count) {
      $count = $this->config('hugs.settings')->get('default_count');
    }
    return [
      '#theme' => 'hug_page',
      '#from' => $from,
      '#to' => $to,
      '#count' => $count
    ];
  }
}

/modules/hugs/hugs.routing.yml


hugs.hug:
  path: /hug/{from}/{to}/{count}
  defaults:
    _controller: 'Drupal\hugs\Controller\HugsController::hug'
    _title: 'Hug!'
    count: 0
  requirements:
    _permission: 'access content'
    count: \d+

/modules/hugs/hugs.module


function hugs_theme() {
  $theme['hug_page'] = [
    'variables' => ['from' => NULL, 'to' => NULL, 'count' => NULL],
    'template' => 'hug_page',
  ];

  return $theme;
}

/modules/hugs/template/hug_page.html.twig


<section>
  {% trans %}
    <strong>{{ from }}</strong> hugs <em>{{ to }}</em> {{ count }} time.
  {% plural count %}
    <strong>{{ from }}</strong> hugs <em>{{ to }}</em> {{ count }} times.
  {% endtrans %}
</section>

How do I...?

make a block

Definitions

Plugin: Swappable, user-defined piece of functionality
Plugin Type: A category of inter-changeable plugins
Discovery: Collecting/cataloging plugins

-- or --

Plugin Type: Interface
Plugin: Implementing class
Discovery: "find all instanceof"

Plugins abstract/automate common OO practices

Drupal 7 extensibility

Info hooks
Little else in common
ctools plugins: PHP 4 yuck
No actual commonality

Drupal 8 extensibility

Want user-configurable logic choices? Plugin
Define interface, define manager class, done

Learn once, apply everywhere

—Lee Rowlands (core developer)

Pluginified systems in Drupal 8

Actions
Blocks
Text formats
Fields
Field Widgets
Field Formatters
Image effects
Conditions
Mail backends
Archiver
Image toolkits
Aggregator (Fetcher, Parser, Processor)
Editor extensions
EntityReference selections
Migration
REST Resources
Search backends
Tours
All of Views…

/modules/hugs/src/Plugin/Block/HugStatus.php


namespace Drupal\hugs\Plugin\Block;

use Drupal\block\BlockBase;

/**
 * Reports on hugability status.
 *
 * @Block(
 *   id = "hugs_status",
 *   admin_label = @Translation("Hug status"),
 *   category = @Translation("System")
 * )
 */
class HugStatus extends BlockBase {

  public function build() {
    return [
      '#markup' => $this->t('This is a hug-enabled site'),
    ];
  }
}

/modules/hugs/src/Plugin/Block/HugStatus.php



class HugStatus extends BlockBase {
  public function defaultConfiguration() {
    return ['enabled' => 1];
  }

  public function blockForm($form, FormStateInterface $form_state) {
    $form['enabled'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Hugging enabled'),
      '#default_value' => $this->configuration['enabled'],
    ];
    return $form;
  }

  public function blockSubmit($form, FormStateInterface $form_state) {
    $this->configuration['enabled'] = (bool)$form_state->getValue('enabled');
  }

  public function build() {
    $message = $this->configuration['enabled']
      ? $this->t('Now accepting hugs')
      : $this->t('No hugs :-(');

    return ['#markup' => $message];
  }
}

Hug configuration form, now with more options

How do I...?

Make a service

Services

"Object that does something"
Stateless
Usually only one of

/modules/hugs/src/HugTracker.php


namespace Drupal\hugs;

use Drupal\Core\State\StateInterface;

class HugTracker {

  protected $state;

  public function __construct(StateInterface $state) {
    $this->state = $state;
  }

  public function addHug($target_name) {
    $this->state->set('hugs.last_recipient', $target_name);
    return $this;
  }

  public function getLastRecipient() {
    return $this->state->get('hugs.last_recipient');
  }
}

/modules/hugs/hugs.services.yml


services:
  hugs.hug_tracker:
    class: Drupal\hugs\HugTracker
    arguments: ['@state']

/modules/hugs/src/Controller/HugsController.php


namespace Drupal\hugs\Controller;
use Drupal\Core\Controller\ControllerBase;
use Drupal\hugs\HugTracker;
use Symfony\Component\DependencyInjection\ContainerInterface;

class HugsController extends ControllerBase {
  protected $hugTracker;

  public function __construct(HugTracker $tracker) {
    $this->hugTracker = $tracker;
  }

  public static function create(ContainerInterface $container) {
    return new static($container->get('hugs.hug_tracker'));
  }

  public function hug($to, $from, $count) {
    $this->hugTracker->addHug($to);
    $count = $count ?: $this->config('hugs.settings')->get('default_count');
    return [
      '#theme' => 'hug_page',
      '#from' => $from,
      '#to' => $to,
      '#count' => $count,
    ];
  }
}

/modules/hugs/src/Plugin/Block/HugStatus.php


namespace Drupal\hugs\Plugin\Block;

class HugStatus extends BlockBase implements ContainerFactoryPluginInterface {
  protected $hugTracker;

  public function __construct(array $configuration, $plugin_id, $plugin_definition,
              HugTracker $hugTracker) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->hugTracker = $hugTracker;
  }

  public static function create(ContainerInterface $container,
              array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration, $plugin_id, $plugin_definition,
      $container->get('hugs.hug_tracker')
    );
  }

  public function build() {
    $message = $this->t('No hugs :-(');
    if ($this->configuration['enabled']) {
      $message = $this->t('@to was the last person hugged', [
        '@to' => $this->hugTracker->getLastRecipient()
      ]);
    }
    return ['#markup' => $message];
  }
  // ...
}

The block is now populated by our service.

How do I...?

Work with content

Entities

Storable ID'd content
Content entities: "Fieldable"
Configuration entities: Useful shortcut

The API is fully baked now!

Content entities

Nodes
Users
Taxonomy terms
Files
Comments
...

/modules/hugs/hugs.routing.yml


hugs.node:
  path: /node/{node}/hug
  defaults:
    _controller: 'Drupal\hugs\Controller\HugsController::nodeHug'
  requirements:
    _permission: 'access content'

/modules/hugs/src/Controller/HugsController.php


class HugsController extends ControllerBase {
  public function nodeHug(NodeInterface $node) {
    if ($node->isPublished()) {
      // These are the same!
      $body = $node->body->value;
      $body = $node->body[0]->value;

      // But we really want...
      $formatted = $node->body->processed;

      foreach ($node->field_tags as $tag) {
        $terms[] = $tag->entity->label();
      }

      $message = $this->t('Everyone hug @name because @reasons!', [
        '@name' => $node->getOwner()->label(), '@reasons' => implode(', ', $terms),
      ]);

      return [
        '#title' => $node->label() . ' (' . $node->bundle() . ')',
        '#markup' => $message . $formatted,
      ];
    }
    return ['#markup' => $this->t('Not published')];
  }
}

That should probably all be in a template...

Drupal in 2 steps:

Build a tool
Wire it up

The wiring may vary, the approach is the same

Guidelines

Small classes, smaller methods
Thin controllers
Logic in services
Not a DB query in sight...
If it's hard to unit test, you're probably doing it wrong

Larry Garfield

Senior Architect, Palantir.net

Let's Make Something Good Together.

Keep tabs on our work at @Palantir