The Core

bitly.com/field-api

• PSR-4

• Everything is an Entity

• Fieldable Blocks

• In-Place Editor

• Core fields:

  • Entity Reference!

  • Date

  • Link

  • Email

  • Phone (<input type="tel">)

  • Comment field!

bitly.com/field-api

• Form modes

Entity Field API

• ContentEntity:
  Everything is a field

• Only !two! interfaces

• • FieldItemListInterface

  • FieldItemInterface

$entity->body;                 //FieldItemListInterface
$entity->field_example;        //FieldItemListInterface
$entity->title;                //FieldItemListInterface

• Item List:

• Item:

• Value:

Pros and Cons

• Translatable
• Revision support
• Iteratable
•  

• Interact with parent objects

+

• Extend Item and ItemList per field type
•  
• Computed fields
•  

• Impossible to use single field for different entity types

Kinds of fields

• Base fields

• Configurable fields

• Custom

Base Fields

Define

public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
  $fields['title'] = BaseFieldDefinition::create('string')
    ->setLabel(t('Title'))
    ->setDescription(t('The title of this node.'))
    ->setRequired(TRUE)
    ->setTranslatable(TRUE)
    ->setRevisionable(TRUE)
    ->setDefaultValue('')
    ->setSetting('max_length', 255)
    ->setDisplayOptions('view', array(
      'label' => 'hidden',
      'type' => 'string',
      'weight' => -5,
    ))
    ->setDisplayOptions('form', array(
      'type' => 'string_textfield',
      'weight' => -5,
    ))
    ->setDisplayConfigurable('form', TRUE);

  // Other base field definitions.

  return $fields;
}

hook_entity_base_field_info()

function hook_entity_base_field_info(\Drupal\Core\Entity\EntityTypeInterface $entity_type) {
  if ($entity_type->id() == 'node') {
    $fields = array();
    $fields['example_text'] = BaseFieldDefinition::create('string')
      ->setLabel(t('Example text'))
      ->setDescription(t('Field description.'))
      ->setComputed(TRUE)
      ->setClass('\Drupal\example_module\EntityComputedText');

    return $fields;
  }
}

Definitions

D7

FieldStorageConfig

Entity type: field_storage_config

$field_storage = FieldStorageConfig::create(array(
  'entity_type' => 'entity_test',
  'field_name' => 'field_test',
  'type' => 'entity_reference',
  'settings' => array(
    'target_type' => 'entity_test',
   ),
   'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
));
$field_storage->save();

$field_storage = entity_create('field_storage_config', array(
  'field_name' => 'body',
  'entity_type' => 'block_content',
  'type' => 'text_with_summary',
));
$field_storage->save();

FieldConfig

Entity type: field_config

uuid: ae2c5b56-a0e5-44d3-ae00-c289200a608f
langcode: en
status: true
dependencies:
  entity:
    - field.storage.node.body
    - node.type.page
id: node.page.body
field_name: body
entity_type: node
bundle: page
label: Body
description: ''
required: false
translatable: true
default_value: {  }
default_value_callback: ''
settings:
  display_summary: true
third_party_settings: {  }
field_type: text_with_summary

field.field.<entity_type>.<bundle>.<field_name>.yml

$entity_manager = Drupal::entityManager();
$entity_manager->getFieldDefinitions($entity_type_id, $bundle);
$entity_manager->getFieldStorageDefinitions($entity_type_id);

Get Definitions

Global:

Plugins

Widget

namespace Drupal\link\Plugin\Field\FieldWidget;

use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\WidgetBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\link\LinkItemInterface;

/**
 * Plugin implementation of the 'link' widget.
 *
 * @FieldWidget(
 *   id = "link_default",
 *   label = @Translation("Link"),
 *   field_types = {
 *     "link"
 *   }
 * )
 */
class LinkWidget extends WidgetBase {  
  // Code here.
}

@see \Drupal\link\Plugin\Field\FieldWidget\LinkWidget

interface WidgetInterface extends WidgetBaseInterface {

  /** Returns a form to configure settings for the widget. */
  public function settingsForm(array $form, FormStateInterface $form_state);

  /** Returns a form to configure settings for the widget. */
  public function settingsSummary();

  /** Returns the form for a single field widget. */
  public function formElement(FieldItemListInterface $items, $delta, 
    array $element, array &$form, FormStateInterface $form_state);

  /** Assigns a field-level validation error to the right widget sub-element. */
  public function errorElement(array $element, ConstraintViolationInterface $violation, 
    array $form, FormStateInterface $form_state);

  /** Massages the form values into the format expected for field values. */
  public function massageFormValues(array $values, array $form, 
    FormStateInterface $form_state);

  /** Returns if the widget can be used for the provided field. */
  public static function isApplicable(FieldDefinitionInterface $field_definition);
}

Formatters

namespace Drupal\link\Plugin\Field\FieldFormatter;

use Drupal\Component\Utility\String;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\FormatterBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;
use Drupal\link\LinkItemInterface;
use Symfony\Component\HttpFoundation\Request;

/**
 * Plugin implementation of the 'link' formatter.
 *
 * @FieldFormatter(
 *   id = "link",
 *   label = @Translation("Link"),
 *   field_types = {
 *     "link"
 *   }
 * )
 */
class LinkFormatter extends FormatterBase {  
  // Code here.
}

@see \Drupal\link\Plugin\field\formatter\LinkFormatter

interface FormatterInterface extends PluginSettingsInterface {

  /** Returns a form to configure settings for the formatter. */
  public function settingsForm(array $form, FormStateInterface $form_state);

  /** Returns a short summary for the current formatter settings. */
  public function settingsSummary();

  /** Allows formatters to load information for field values being displayed. */
  public function prepareView(array $entities_items);

  /** Builds a renderable array for a fully themed field. */
  public function view(FieldItemListInterface $items);

  /** Builds a renderable array for a field value. */
  public function viewElements(FieldItemListInterface $items);

  /** Returns if the formatter can be used for the provided field. */
  public static function isApplicable(FieldDefinitionInterface $field_definition);

}

Field Type

namespace Drupal\link\Plugin\Field\FieldType;

use Drupal\Component\Utility\Random;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldItemBase;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\TypedData\DataDefinition;
use Drupal\Core\TypedData\MapDataDefinition;
use Drupal\link\LinkItemInterface;

/**
 * Plugin implementation of the 'link' field type.
 *
 * @FieldType(
 *   id = "link",
 *   label = @Translation("Link"),
 *   description = @Translation("Stores a URL string..."),
 *   default_widget = "link_default",
 *   default_formatter = "link",
 *   constraints = {"LinkType" = {}}
 * )
 */
class LinkItem extends FieldItemBase implements LinkItemInterface {
  // Code here.
}

@see \Drupal\link\Plugin\Field\FieldType\LinkItem

interface FieldItemInterface extends ComplexDataInterface {
  // Magic methods.
  public function __get($property_name);
  public function __set($property_name, $value);
  public function __isset($property_name);
  public function __unset($property_name);

  public static function propertyDefinitions(
    FieldStorageDefinitionInterface $field_definition);
  public static function mainPropertyName();
  public static function schema(FieldStorageDefinitionInterface $field_definition);
  public function getEntity();
  public function getLangcode();
  public function getFieldDefinition();
  public function view($display_options = array());
  public function preSave();
  public function insert();
  public function update();
  public function delete();
  public function deleteRevision();
  public static function generateSampleValue(FieldDefinitionInterface $field_definition);
  public static function defaultStorageSettings();
  public static function defaultFieldSettings();
  public static function storageSettingsToConfigData(array $settings);
  public static function storageSettingsFromConfigData(array $settings);
  public static function fieldSettingsToConfigData(array $settings);
  public static function fieldSettingsFromConfigData(array $settings);
  public function storageSettingsForm(array &$form, 
    FormStateInterface $form_state, $has_data);
  public function fieldSettingsForm(array $form, FormStateInterface $form_state);
}

@see http://bitly.com/d8-field-item-interface

Useful links

• Entity API in Drupal 8

• Typed Data API in Drupal 8

• Field API is dead. Long live Entity Field API!

• Drupal 8 Entity Cheat Sheet

• Drupal 8 Field API series part 1: field formatters

• Drupal 8 Field API series part 2: field widgets

bitly.com/field-api-links

THANK YOU!

Dmitry Olaresko

skype: d.olaresko

email: dolaresko@adyax.com

bitly.com/field-api