This document provides an overview of WordPress and discusses how it can be used as a web application framework. It describes key aspects of the WordPress data model including custom post types, post meta, taxonomies, and relationships. It also covers templates, querying data, users, internationalization, AJAX, APIs, caching, and rewrite rules. Both advantages like its large community and plugins as well as disadvantages like performance overhead are acknowledged.

1. Using WordPress
as a framework
Marco Martins

2. WordPress is a
blogging tool

3. WordPress is a
Content Management System

4. WordPress is a web
application framework

5. but is it?

6. A web application framework is a software
framework that is designed to support the
development of dynamic websites, web applications,
web services and web resources. The framework
aims to alleviate the overhead associated with
common activities performed in web development.
For example, many frameworks provide libraries for
database access, templating frameworks and session
management, and they often promote code reuse.
from Wikipedia (2015, May 9)

7. Data Model

8. • Custom Post Types
• Post Meta
• Taxonomies
• Posts 2 Posts

9. Custom Post Types
• Represent the model definition
• You can define:
• some content fields
• visibility (queryable, searchable, show in menus…)
• capabilities
• hierarchical
• rewrites & query vars
register_post_type( $post_type, $args );

10. Post Meta
• Adds extra fields to the model
• Extends the basic model data (title, editor,
image…) with extra fields (wysiwyg, embed,
field groups, repeatable fields…
• Plugins: CMB2, ACF, Custom-Meta-Boxes

11. Taxonomies
• Custom taxonomies
• Custom taxonomies can be attached to specific
content types
register_taxonomy( $taxonomy, $object_type, $args );

12. Posts 2 Posts
• Plugin
• Creates relationships between content types (including users)
• Supports cardinality
• Allows relationship meta data.
• Development of the plugin has not been active
• @link https://wordpress.org/plugins/posts-to-posts/

13. Template System

14. Template System
• PHP based templating
• Templates can be used in plugins
• Templates can be loaded programatically

15. Accessing Data

16. WP_Query
• Very central class in WordPress
• Makes queries by: post type, taxonomy, post meta, date,
taxonomy
$args = array(
'post_type' => ‘address',
'tax_query' => array(
array(
'taxonomy' => ‘type',
'field' => ‘slug',
'terms' => ‘shipping’,
),
),
);
$addresses = new WP_Query( $args );

17. $wpdb
• Global object to access the database
• Escapes data
$wpdb->insert( $table, $data, $format );
$wpdb->replace( $table, $data, $format );
$wpdb->update( $table, $data, $where, [$format],
[$where_format] );
$wpdb->delete( $table, $where, $where_format = null );
$wpdb->prepare( 'query', value_parameter[, value_parameter] );

18. Users

19. Users
• Supports user roles
• Supports user capabilities
• User information can be extended
• New roles and capabilities can be created
• Meta capabilities can be created
• Authentication method can be changed using hooks

20. Internationalization
&
Localization

21. Internationalization
• Gettext functions (partial list):
__( $text, $text_domain );
_e( $text, $text_domain );
_x( $text, $context, $text_domain );
• Loading text domain
function demo_load_textdomain() {
load_plugin_textdomain( ‘demo', FALSE,
basename( dirname( __FILE__ ) ) . '/languages/' );
}
add_action( 'plugins_loaded', 'demo_load_textdomain' );

22. Localization
• POT files
• i18n tools (makepot.php / grunt-pot)

23. Ajax

24. Ajax
• Set the Ajax URL
function set_ajax_url() { ?>
<script type=“text/javascript">
var ajaxurl = "<?php echo admin_url('admin-ajax.php'); ?>";
</script>
<?php } ?>

25. Ajax
• Register the request handler
function callback() {
echo json_encode( array( ‘success’ => true ) ); die();
}
add_action( ‘wp_ajax_demo', 'callback' );
add_action( 'wp_ajax_nopriv_demo', 'callback' );

26. Ajax
• Making the requests
$.getJSON(ajaxurl, {action: ‘demo' }, function( data ){
console.log(‘data’);
});

27. Consuming
External APIs

28. HTTP API
• Standardizes and abstracts HTTP requests
• Supports and abstracts multiple PHP HTTP methods (cURL,
file_get_contents)
wp_remote_get( $url, $args ); / wp_remote_post( $url, $args );
wp_remote_request( $url, $args );
wp_remote_retrieve_body( $response );
wp_remote_retrieve_headers( $response, $header );
wp_remote_retrieve_response_code( $response );

29. API Provider

30. WP REST API
• Provides a HTTP REST API to interact with WordPress
• Posts, Post Meta, Users, Media… can be created, read, changed, and deleted
• Basic Authentication and Oauth are available
• Currently the API is available as a plugin but soon it will be part of the WordPress core
• @link http://wp-api.org/
GET /posts
GET /posts/<id>
*POST /posts
*PUT /posts/<id>
*POST /posts/<id>/meta

31. Caching

32. Transients API
• Core API
• Similar to the Options API
• Data can be stored in the database, Redis,
Memcached…
• Can be used on the network level and site level

33. Transients API
set_transient( $transient, $value, $expiration_in_seconds )
get_transient( $transient );
delete_transient( $transient );
set_site_transient( $transient, $value, $expiration_in_seconds );
get_site_transient( $transient );
delete_site_transient( $transient );

34. TLC Transients
• Soft expiration
• Can refresh the cache in the background
• https://github.com/markjaquith/WP-TLC-
Transients

35. TLC Transients
<?php
function my_callback_with_param( $param ) {
return str_replace(
'foo',
$param,
wp_remote_retrieve_body( wp_remote_get( 'http://example.com/feed.xml', array( 'timeout' => 30 ) ) ),
);
}
echo tlc_transient( 'example-feed' )
->updates_with( 'my_callback_with_param', array( 'bar' ) )
->expires_in( 300 )
->background_only()
->get();

36. URLs

37. Rewrite API
• Allows you to create new rewrite rules and
permalink structures programatically
• You can create “pages” without having to create
a page in the dashboard.
• Uses WP_Rewrite API

38. Rewrite API
add_rewrite_tag( '%orders%', '([^&]+)' );
add_rewrite_tag( ‘%order_id%', '([^&]+)' );
add_rewrite_rule( $base .
'/orders/([^/]*)/?$',
'index.php?' . $base .
'=true&orders=true&order_id=$matches[1]',
'top'
);

39. More Tools

40. More Tools
• WP_Error
• Options API
• Filesystem API
• Settings API
• Shortcode API
• Input Validation & Output Sanitization
• Media Management Functions
• Custom Post Statuses
• …

41. Advantages

42. Advantages
• Dashboard
• Multisite
• Documentation & Community
• Plugin repository
• Hooks (actions & filters) in both core and plugins
• Automatic updates

43. But it’s not all rainbows
and butterflies

44. Disadvantages
• Lack of a proper template engine
• Doesn’t enforce a strict MVC
• Performance (you need to load WordPress)

45. Extra
• WP_Mock (mocks WordPress for unit tests)
• Caching plugins (W3 Total Cache, WP Super
Cache)
• Plugin frameworks
• WPlinth

46. • @fimdalinha
• https://fi.linkedin.com/in/marconmartins
• h1.fi