Filters & Actions

Hooks are a way for one piece of code to interact/modify another piece of code at specific, pre-defined spots. You can 'hook' into them to modify a set piece of code. Hooks come in the form of actions and filters.

Actions

Actions allow you to add data or change how WordPress operates. Actions will run at a specific point in the execution of WordPress Core, plugins, and themes. Callback functions for Actions can perform some kind of a task, like echoing output to the user or inserting something into the database. Callback functions for an Action do not return anything back to the calling Action hook.

We use actions in wp-lemon throughout the twig files to add new data on specific spots without overwriting the complete twig file. This means you can upgrade your child themes more easily in the future.

Filters

Filters give you the ability to change data during the execution of WordPress Core, plugins, and themes. Callback functions for Filters will accept a variable, modify it, and return it. They are meant to work in an isolated manner, and should never have side effects such as affecting global variables and output. Filters expect to have something returned back to them.

We use filters in wp-lemon to change specific output that is already baked into the templates. It serves the same purpose as actions are used on a smaller scale, like changing an icon inside a card for example.

Actions inside blocks

Hooks are in the correct order.

Actions inside wp-lemon core files

Hooks are in the correct order.

Examples

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1namespace WP_Lemon\Child\Controllers;
2
3use Timber\Timber;
4use function HighGround\Bulldozer\helpers\asset;
5
6/**
7 * Add static contact bar on every page.
8 *
9 * @return void
10 */
11function add_contact_bar()
12{
13   $context = Timber::get_context();
14   $context['classes'] = array('acf-block', 'contact-bar', 'alignfull', 'has-background', 'has-blue-background-color', 'has-text-color', 'has-black-color');
15
16   Timber::render('blocks/contact-bar.twig', $context);
17}
18
19add_action('wp-lemon/action/content/after', __NAMESPACE__ . '\\add_contact_bar');
20
21/**
22 * Insert logo's of certificates directly after the footer widgets.
23 *
24 * @return void
25 */
26function footer_logos()
27{
28   $context = Timber::get_context();
29   $context['footer_logos'] = [
30      asset('images/logos/ebn-9001.svg')->uri(),
31      asset('images/logos/veritas-f-gassen.svg')->uri(),
32      asset('images/logos/techniek-nederland.svg')->uri(),
33      asset('images/logos/veritas-brl-6000.svg')->uri(),
34      asset('images/logos/ebn-vca.svg')->uri(),
35   ];
36
37   Timber::render('partials/footer-logos.twig', $context);
38}
39
40add_action('wp-lemon/action/footer-widgets/after', __NAMESPACE__ . '\\footer_logos');

Filters available inside regular PHP files.

Filters available inside models

Filters available PHP block declarations

Filters available Twig files

Examples

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1namespace WP_Lemon\Child\Controllers;
2
3
4add_filter('wp-lemon/filter/card/icon', function () {
5   return 'icon-chevron-right';
6});
7
8add_filter("wp-lemon/filter/node-overview/news/image-sizes", function ($sizes) {
9   return '(min-width: 768px) 700px,
10           (min-width: 600px) 510px,
11           400px';
12});
13
14
15add_filter('wp-lemon/filter/card/news/picture-el', function ($el, $post_id) {
16   return get_field('oembed', $post_id);
17}, 10, 2);