In this article, we\u2019ll cover the basics of hooks, actions, and filters, and then walk you through some examples. Let\u2019s get started!<\/p>\n\n\n\n
Key Terms Related to Hooks<\/h2>\n\n\n\n
It\u2019s helpful to have a little background before we dive into how to create your own hooks. There are a few common terms that you\u2019ll frequently run across when dealing with hooks: actions, filters, Actions and filters are the two basic functions performed by hooks, while An action is a function performed when a given event occurs in WordPress. In other words, actions do<\/em> something. Some common examples of actions include:<\/p>\n\n\n\n Actions are already in use on nearly every WordPress site, although they\u2019re typically hidden behind the Graphical User Interface (GUI) of themes and plugins. You\u2019ll only really see them if you intentionally dig into the source code to look for them \u2013 or if you write your own code<\/a>.<\/p>\n\n\n\n If an action is a do<\/em> hook, a filter is a change <\/em>hook. This type of hook enables you to modify another function. Common examples of filters in action include:<\/p>\n\n\n\n Like actions, you\u2019re probably using filters all over your website already, without even knowing it.<\/p>\n\n\n\n The Next up, Now that you understand the basics of hooks, it\u2019s time to create one of your own. To do that, you need to know that hooks are made up of three basic parts: <\/p>\n\n\n\n For the most part, the hook, action, and filter will already be defined within either the WordPress core files or your theme\u2019s files. This means you\u2019ll just need to connect the two, and depending on the function you want to execute, add some parameters.<\/p>\n\n\n\n For the latter, you can consult the relevant page on the WordPress Codex<\/a>. Let\u2019s see what all of this looks like in action with a couple of examples.<\/p>\n\n\n\n To illustrate an action hook, we\u2019ll use The The action, noindex, is found in wp-includes\/general-template.php. <\/em>This file is part of WordPress core, and contains the following code<\/a>:<\/p>\n\n\n\n You\u2019ll need to connect these two with a callback in the functions.php <\/em>file<\/a> of your theme. It\u2019s best to add this to a child theme<\/a> rather than to your main theme, because it may otherwise get overwritten when the theme updates.<\/p>\n\n\n\n Open up your functions.php<\/em> file in your WordPress dashboard (Appearance > Theme Editor<\/em>), and add the following code to the bottom of the file:<\/p>\n\n\n\n Now, when the header loads it will perform the noindex function, which \u2018tells robots to go away\u2019. <\/p>\n\n\n\n For our filter example, we\u2019ll use The hook, The Here\u2019s the code you need to add to functions.php<\/em> in order to connect these two:<\/p>\n\n\n\n Once you\u2019ve added the code and saved the file, your new hook should start doing its job right away.<\/p>\n\n\n\n There are an incredible number of hooks built into WordPress. Memorizing all of them is a challenge, even for seasoned developers. Fortunately, there are some excellent references online that list all of the available hooks. The Action Reference<\/a> and Filter Reference<\/a> on the WordPress Codex<\/a> are perfect starting points.<\/p>\n\n\n\n Hooks in WordPress enable you to quickly customize your site. Plus, you don\u2019t have to be a pro web developer to use them. Even a coding newbie can learn to implement hooks in WordPress with a little practice. <\/p>\n\n\n\nwp_head<\/code>, and the_content<\/code>.<\/p>\n\n\n\nwp_head<\/code> and the_content<\/code> are two of the most commonly-used hooks for actions and filters, respectively.<\/p>\n\n\n\nAction<\/h3>\n\n\n\n
Filter<\/h3>\n\n\n\n
wp_head<\/h3>\n\n\n\n
wp_head<\/code> action hook triggers an action in the header of your page \u2013 inside the <head><\/head><\/code> section of the theme\u2019s code. This is important because numerous critical functions are located within the header in WordPress. Some examples include Google Analytics tracking codes<\/a> and the noindex action, which tells search engines to not include a page in search results.\u00a0<\/p>\n\n\n\nthe_content<\/h3>\n\n\n\n
the_content<\/code> is a filter that applies to the content of a post. It\u2019s used to apply basic formatting \u2013 a common example is adding paragraph tags and line breaks into a post\u2019s code automatically. Another frequent use of the_content<\/code> filters is displaying social sharing buttons at the bottom of a post.<\/p>\n\n\n\nHow Do I Create a Hook in WordPress?<\/h2>\n\n\n\n
Example of an Action Hook<\/h3>\n\n\n\n
wp_head<\/code> and the noindex<\/code> function. This is a fairly common function that tells search engine crawlers to skip indexing a page<\/a>, and it\u2019s typically run from the page\u2019s header section.\u00a0<\/p>\n\n\n\nwp_head<\/code> hook is found in your theme\u2019s header.php<\/em> file:<\/p>\n\n\n\n![\"Image](\"https:\/\/lh3.googleusercontent.com\/JYsXnx_B7snLns2uWx89VmMWPHdgp79kNdxzOcWeRefp9cvayI_zC1Zul0RylcYFANle9m7G7Jehe9as6V-wUhDe6JT9Su3oD6NnHe2XWdQ7Bu1jXdlaKpFF_bL02SmOwwIExkOs\")
function noindex() {
\/\/ If the blog is not public, tell robots to go away.
if ( '0' == get_option( 'blog_public' ) ) {
wp_no_robots()
\u00a0\u00a0\u00a0}
}<\/code><\/p>\n\n\n\nadd_action( 'wp_head', 'noindex' );<\/code><\/p>\n\n\n\nExample of a Filter Hook<\/h3>\n\n\n\n
the_content<\/code> and wpautop<\/code>. This function automatically adds HTML tags for your paragraphs and includes line breaks between them, so they\u2019re properly displayed in the browser.<\/p>\n\n\n\nthe_content<\/code>, is found in the wp-includes\/post-template.php <\/em>file. This is the relevant code:<\/p>\n\n\n\napply_filters( 'the_content', string $content )<\/code><\/p>\n\n\n\nwpautop<\/code> function is found in the wp-includes\/formatting.php<\/em> file. Here\u2019s what it looks like:<\/p>\n\n\n\nfunction wpautop( $pee, $br = true ) {
\u00a0\/\/ \u2026
return $pee;
}<\/code><\/p>\n\n\n\nadd_filter( 'the_content', 'wpautop' );<\/code><\/p>\n\n\n\nWhere Can I Find a List of All WordPress Hooks?<\/h2>\n\n\n\n
Explore WP Engine\u2019s Developer Resources<\/h2>\n\n\n\n