{Drupal 7 Entities

Entities, nodes, fields, the Entity API & TextbookMadness.com

JD LeonardFreelance Drupal Consultant & DeveloperFounder, TextbookMadness.com

{ Berkeley DUG 2/27/12{

Agenda: How data is represented

Drupal 6 vs. Drupal 7 Entities Fields (CCK)

Entities vs. nodes The Entity API (contrib module) Live example: entities, nodes, and fields

used to build TextbookMadness.com

Entities, Entities, Entities

Powerful new concept in Drupal 7

{ {Drupal 6

{Custom DB table}

User Comment Taxonomy Node

Page Blog post {Custom node

type}

Drupal 7

{Custom DB table] Entity

User Comment Taxonomy Node

Page Blog post {Custom node

type} {Custom entity

type}

Drupal Data

Elemental building block for most data in Drupal 7

Represents a concept or noun In core: user, comment, taxonomy, & node Stores data differently

Generally in a single DB table Node

Title, body, created timestamp User

Username, created timestamp, last visit timestamp

Defined using hook_entity_info() – example later!

Entity Types

Instance of an entity type In core:

Users, comments, taxonomies, and nodes are entities

Eg: the user jdl1234 with uid 12 is an entity Eg: the page “Drupal rocks” with nid 44 is an

entity Any entity can be loaded with entity_load()

Eg: entity_load(‘node’, array(44, 65)) Returns an array with two nodes with nids 44 and

65 Core provides some wrappers that do extra

work Eg: node_load() and user_load()

Entity

Bundle Subtype of an entity Eg: page & blog post

Two content types of node entity type “Bundles” of node entity type

Not all entity types have more than one Eg: user

Concept stands on its own Why bother?

Each entity type stores some data in a table Eg: node

Title, body, created timestamp But not all nodes are created equal

Page may have data beyond that captured by node Blog posts get tagged

Entity Bundles

Drupal 6 CCK (Content Construction Kit) Contrib module Store additional data per content (node) type Eg: Fivestar

Contrib module leveraging contrib CCK API Allows nodes to be rated (think 1-5 stars)

Eg: let users rate pages Drupal 7 fields

Core concept Store additional data per entity type Applies power of CCK to all entity types Eg: Fivestar

Contrib module leveraging core Field API Allows entities to be rated

Eg: let users rate pages, users, comments, custom entities

CCK, Fields, & Entities

Similarities Represent “things”; store data Fieldable Types can be defined in code

Entities & Nodes

{ {Nodes

Site building UI to add/edit

content types, fields, and content

Versioning built in Data stored in

nodes table and fields

Entities

Optionally fieldable

Development Lightweight No UI provided Data storage up to

you Can be more

performant/scalable

Entities vs. Nodes

Entities are a Drupal 7 core concept Core functions and hooks provided to interact

with entities and entity types EntityFieldQuery

Core API for querying entities Can query entity data (“properties”) and field

data Can query field data across entity types

Eg: “return all pages and users tagged with taxonomy term 456”

Returns entity IDs Usually you’ll then load with entity_load()

The Entity API contrib module builds on core

Core Entities & Entity API

Makes dealing with entities easier Provides full CRUD functionality

CReate, Update, and Delete Allows definition of metadata about entities

and relationships between them Views integration Rules integration Search API integration

Optionally make data exportable Optional administrative UI for managing

entities Object-oriented representation of entity types

Enables extending an entity type’s functionality

Entity API

Profile2 Organic Groups Rules Message Drupal commerce … and lots more!

Modules Using Entity API

Drupal 7 site Cross between Craigslist and Kayak

Free textbook classified listings Private to each college we partner with Helps students buy and sell used books with each

other Online price comparison

Prices from 30+ online retailers Amazon, Half, Chegg, Textbooks.com, you name

it New, used, rental, international edition, eBook,

and buyback prices Uses entities and the Entity API Demo!

TextbookMadness.com

Users (John Smith) Schools (Rice University) Retailers (Amazon.com Textbooks (with an ISBN) Offers (online prices) Listings (student book classifieds)

Everything above except users are defined as custom entity types

Textbook Madness Data

/* Implements hook_entity_info(). // Drupal core hook */function tbm_entity_info() { $entities = array( 'tbm_school' => array( // Machine name for my entity 'label' => t('School'), 'plural label' => t('Schools'), 'entity class' => 'TbmSchoolEntity', // Advanced. You can put ‘Entity’ 'controller class' => 'TbmSchoolEntityController', // Advanced. You can put ‘EntityAPIController’ 'base table' => 'tbm_school', // Name of the related table defined in hook_schema() in tbm.install 'fieldable' => FALSE, 'entity keys' => array( 'id' => 'school_id', // Primary key as defined in hook_schema() 'label' => 'name', // Column in hook_schema() to be used to represent the entity in a friendly way ), 'uri callback' => 'entity_class_uri', 'access callback' => 'tbm_school_access', // Callback defined to return TRUE if the school is enabled 'module' => 'tbm', // My module name 'admin ui' => array( 'path' => 'admin/structure/schools', 'file' => 'tbm.admin.inc', // Where tbm_school_form() for add/edit form is defined 'file path' => drupal_get_path('module', 'tbm') . '/pages', ), ), ); return $entities;}

School Entity Definition

/* Implements hook_schema(). */function tbm_schema() { $schema['tbm_school'] = array( 'fields' => array( 'school_id' => array('type' => 'serial', 'size' => 'small', 'unsigned' => TRUE, 'not null' => TRUE), 'machine_name' => array('type' => 'varchar', 'length' => 100, 'not null' => TRUE, 'description' => 'The machine name of the school.'), 'name' => array('type' => 'varchar', 'length' => 128, 'not null' => TRUE, 'description' => 'The name of the school.'), 'name_short' => array('type' => 'varchar', 'length' => 64, 'description' => 'The short name of the school.'), 'name_long' => array('type' => 'varchar', 'length' => 255, 'description' => 'The long name of the school.'), 'url' => array('type' => 'varchar', 'length' => 1024, 'not null' => TRUE, 'description' => 'The URL of the school\'s homepage.'), 'email_domains' => array('type' => 'varchar', 'length' => 1024, 'description' => 'The email domains (comma delimited) valid for the school.'), 'sponsor1_name' => array('type' => 'varchar', 'length' => 64, 'description' => 'The name of the first sponsor.'), 'sponsor1_name_short' => array('type' => 'varchar', 'length' => 32, 'description' => 'The short name of the first sponsor.'), 'sponsor1_name_long' => array('type' => 'varchar', 'length' => 128, 'description' => 'The long name of the first sponsor.'), 'sponsor1_url' => array('type' => 'varchar', 'length' => 1024, 'description' => 'The URL of the first sponsor\'s homepage.'), 'sponsor2_name' => array('type' => 'varchar', 'length' => 64, 'description' => 'The name of the second sponsor.'), 'sponsor2_name_short' => array('type' => 'varchar', 'length' => 32, 'description' => 'The short name of the second sponsor.'), 'sponsor2_name_long' => array('type' => 'varchar', 'length' => 128, 'description' => 'The long name of the second sponsor.'), 'sponsor2_url' => array('type' => 'varchar', 'length' => 1024, 'description' => 'The URL of the second sponsor\'s homepage.'), 'enabled' => array('type' => 'int', 'size' => 'tiny', 'unsigned' => TRUE, 'not null' => TRUE, 'description' => 'Whether the school is enabled.'), 'listed' => array('type' => 'int', 'size' => 'tiny', 'unsigned' => TRUE, 'not null' => TRUE, 'description' => 'Whether the school is listed.'), ), 'primary key' => array('school_id'), 'unique keys' => array( 'machine_name' => array('machine_name'), ), ); return $schema;}

School Schema Definition

This function shows how to use an EntityFieldQuery Users are necessarily associated with a school I have a field, field_school, attached to the user entity type,

which stores this relationship data The query finds active users (status == 1) at the given

school

/** * Load an array of uids of users at the school with the given ID. * @param int $school_id The ID of the school to load users for */function tbm_school_uids($school_id) { $query = new EntityFieldQuery();

$result = $query ->entityCondition('entity_type', 'user') ->propertyCondition('status', 1) ->fieldCondition('field_school', 'school_id', $school_id) ->execute(); return array_key_exists('user', $result) ? array_keys($result['user']) : array();}

School EntityFieldQuery

The end!