Entities in Drupal 7 & the Entity API #sfdug March 11, 2013 JD Leonard ModernBizConsulting.com

About Me Computer science background Working with Drupal since 2006 Developer, architect, project manager Freelance through my business: Modern Biz Consulting Focus on complex web application development

Agenda Ways we represent data in D6 vs D7 Entities, entity types, & bundles Fields (formerly CCK) The Entity API contrib module How (and why) to define a custom entity Using EntityFieldQuery Defining entity property info Leveraging the Entity Metadata Wrapper

Poll Who here is... –Brand new to Drupal? –A site builder? –A module developer? –On the business side of things? Who here has... –Created a custom D7 entity? –Not created a custom D7 entity?

D6 Data (Custom database table) User Comment File Taxonomy vocabulary Taxonomy term Node –Page, Blog post, (custom content type)

D7 Data (Custom database table) Entity –User –Comment –File –Taxonomy vocabulary –Taxonomy term –Node Page, Blog post, (custom content type) (Custom entity type)

Entity Types Elemental building block for most important data in Drupal 7 Represents a concept or noun Different types store different data –Generally in a single DB table –Eg: Node Title, body, created timestamp, etc. –Eg: User Username, created timestamp, last visit timestamp, etc. Defined using hook_entity_info()

Entity Instance of an entity type Examples of entities from core: –The user jdleonard with uid –The page “Drupal Rocks” with nid 44 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 convenience wrappers Eg: node_load() and user_load()

Entity Bundles Subtype of an entity Eg: Page and Blog post –Two content types (bundles) of node entity type Not all entity types have more than one bundle –Eg: User No subtypes; concept stands on its own

Why We Need Entity Bundles Each entity type stores some data in a table –We call these pieces of data “properties” –Eg: node Title, body, author (uid), created timestamp But not all nodes are created equal –Page may have data beyond that captured by node –Blog posts get tagged –We need fields!

CCK: Content Construction Kit (D6) Contrib module Store additional data per content (node) content type Eg: Fivestar –Contrib module leveraging contrib CCK API –Allows nodes to be rated (think 1-5 stars) –Eg: let users rate pages or blog posts

Fields (D7) Core concept Store additional data per entity type Applies power of CCK to all entity types –Not just nodes! Eg: Fivestar –Contrib module leveraging core Field API –Allows entities to be rated –Eg: let users rate pages, blog posts, users, comments, custom entities

Entities in Core vs Contrib Entities are a Drupal 7 core concept Core provides the “Entity API” –Functions and hooks to define and interact with entities, entity types, and entity bundles Everything we've discussed so far is part of Drupal 7 core (no contrib modules necessary) Not everything “made it into” core –Thankfully there's the “Entity API” contrib module (confusingly named)

Entity API Contrib Module Makes dealing with entities easier Provides full CRUD functionality –CReate, Update, and Delete Allows definition of metadata about entities Optionally makes entity data –Exportable (for configuration) –Revisionable (eg: node revisions) Optional administrative UI for managing entities Object-oriented representation of entity types

A Note on Documentation Documentation for core's Entity API is separate from that for the Entity API contrib module In practice, you'll probably always use the Entity API contrib module –It provides so much awesome functionality! Don't get confused –Always install the Entity API contrib module when defining an entity –Make sure to read the module's documentation

Contrib Modules Defining Entities Commerce –Commerce Product, Commerce Payment Transaction Organic Groups –OG Membership, OG Membership Type Rules –Rules Configuration Message (think activity stream) –Message, Message Type, Message Type Category … and many more!

Example Custom Entity Type TextbookMadness.com –Classified listings for textbooks at schools –Online price comparison shopping (prices from Amazon, Textbooks.com, etc.) Online prices are –Fetched from a third-party API and stored by Drupal –Hereafter known as Offers

How Shall we Define an Offer? We could use the UI to define an offer node with a bunch of fields to store pricing information But there's a lot of overhead! –Don't need/want a page (path) per offer –Don't need/want revisions –Don't need/want node base table information Language (and translation info), Title, Author, Published status, Created date, Commenting, Promoting, etc. We want an entity!

Implement hook_schema() $schema['tbm_offer'] = array( // SIMPLIFIED FOR SLIDE 'fields' => array( 'offer_id' => array('type' => 'serial'), 'isbn' => array('type' => 'int'), 'retailer_id' => array('type' => 'int'), 'price' => array('type' => 'int'), 'last_updated' => array('type' => 'int'), ), 'primary key' => array('offer_id') );

Implement hook_entity_info() $entities['tbm_offer'] = array( 'label' => t('Offer'), 'plural label' => t('Offers'), 'entity class' => 'Entity', 'controller class' => 'EntityAPIController', 'module' => 'tbm', 'base table' => 'tbm_offer', 'fieldable' => FALSE, 'entity keys' => array( 'id' => 'offer_id', ));

Make an Entity Type Exportable $entities['tbm_offer'] = array( 'label' => t('Offer'), 'plural label' => t('Offers'), 'entity class' => 'Entity', 'controller class' => 'EntityAPIControllerExportable', 'module' => 'tbm', 'base table' => 'tbm_offer', 'fieldable' => FALSE, 'exportable' => TRUE, 'entity keys' => array( 'id' => 'offer_id', 'name' => 'my_machine_name' ));

Make an Entity Type Revisionable $entities['tbm_offer'] = array( 'label' => t('Offer'), 'plural label' => t('Offers'), 'entity class' => 'Entity', 'controller class' => 'EntityAPIController', 'module' => 'tbm', 'base table' => 'tbm_offer', 'revision_table' => 'tbm_o_revision', 'fieldable' => FALSE, 'entity keys' => array( 'id' => 'offer_id', 'revision' => 'revision_id', ));

Other hook_entity_info() configuration $entities['tbm_offer'] = array( … 'entity class' => 'TbmOfferEntity', // Extends Entity class 'controller class' => 'TbmOfferEntityController', 'access callback' => 'tbm_offer_access', 'admin ui' => array( 'path' => 'admin/structure/offers', 'file' => 'tbm.admin.inc', ), 'label callback' => 'entity_class_label', 'uri callback' => 'entity_class_uri', ); // TbmOfferEntity->defaultLabel(), defaultUri()

Entity Property Info hook_entity_property_info() –Defines entity metadata –Provided for core entities Automatically generated from hook_schema() –Doesn't understand foreign key relationships (references) –Doesn't know when an integer is actually a date (eg: unix timestamps) Fill in the gaps with hook_entity_property_info_alter()

hook_entity_property_info_alter() $offer = &$info['tbm_offer']['properties']; $offer['url']['type'] = 'uri'; // was a varchar in hook_schema $offer['url']['label'] = 'URL'; $offer['last_updated']['type'] = 'date'; // integer in hook_schema $offer['last_updated']['label'] = t('Last updated'); // Other types: text, token (machine name), integer, decimal, duration, boolean, entity, struct, list

hook_entity_property_info_alter() // Define a new property to reference an offer's retailer (eg: Amazon.com) $offer['retailer'] = array( 'label' => t('Retailer'), 'type' => 'tbm_retailer', // The tbm_retailer entity type 'description' => t('The retailer making the offer.'), 'required' => TRUE, 'schema field' => 'retailer_id', // as defined in hook_schema );

Entity API Integrations Views –Eg: in a view of offers, we can add a retailer relationship and include details about each offer's retailer Rules Search API Features I18n Token system - Eg: [tbm_offer:retailer:name]

EntityFieldQuery Tool for querying entities Can query entity 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()

EntityFieldQuery Example $query = new EntityFieldQuery(); $query ->entityCondition('entity_type', 'node') ->entityCondition('bundle', 'page') ->propertyCondition('status', 1) ->fieldCondition('field_awesome_factor', 'value', 3.2, '<') ->fieldOrderBy('field_awesome_factor', 'value', 'DESC') ->range(0, 10); // Top 10 Published page nodes with an awesome factor < 3.2

EntityFieldQuery Example $result = $query->execute(); // Keyed by entity type if (isset($result['node'])) { $nids = array_keys($result['node']); $pages = node_load_multiple($nids); $same_as_pages = entity_load('node', $nids); }

Entity Metadata Wrapper Examples // Get node author's address (given $nid) // BEFORE $node = node_load($nid); $author = user_load($node->uid); $ = check_plain($author->mail); // AFTER $wrapper = entity_metadata_wrapper('node', $nid); $ = $wrapper->author->mail->value();

Entity Metadata Wrapper Examples // Set node author's address $wrapper->author->mail = $wrapper->save(); // Iterate over a list of node's taxonomy terms foreach ($wrapper->field_taxonomy_terms->getIterator() as $term_wrapper) { $label = $term_wrapper->label->value(); }

More Modules! Entity Construction Kit (ECK) Entity Construction Kit –CCK for entities –Create entity types in a UI Entity Cache –Integrates entities with Drupal's Cache API Entity Reference –Like node reference field, but for any type of entity Automatic Entity Label –Generic successor to Automatic Node Titles

More information Entity API documentation –Lots of information in many subpages EntityFieldQuery documentation Entity API contrib module page Deck is on SlideshareSlideshare me: jd at ModernBizConsulting.com Follow me: