Overview Overview

An important — but often overlooked — best practice is adding custom hooksHooks In WordPress theme and development, hooks are functions that can be applied to an action or a Filter in WordPress. Actions are functions performed when a certain event occurs in WordPress. Filters allow you to modify certain functions. Arguments used to hook both filters and actions look the same. to your pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party so that other developers can extend and modify it, without having to fork it.

Custom hooks are created and called in the same way that CoreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress.’s hooks are, with add_action() / do_action() and add_filter() / apply_filters().

Since any plugin can create a custom hook, it’s important to prefix your hook names to avoid collisions with other plugins. For example, a filterFilter Filters are one of the two types of Hooks https://codex.wordpress.org/Plugin_API/Hooks. They provide a way for functions to modify data of other functions. They are the counterpart to Actions. Unlike Actions, filters are meant to work in an isolated manner, and should never have side effects such as affecting global variables and output. named email_body would be bad because it’s likely that another developer will choose that same name. If the user installs both plugins, it could lead to bugs that are difficult to track down. Naming the function abcd_email_body (where “abcd” is a unique prefix for your plugin) would avoid any collisions.

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Examples Examples

Creating an ExtensibleExtensible This is the ability to add additional functionality to the code. Plugins extend the WordPress core software. Settings Form

If your plugin adds a settings form to the Administrative Panels, you can use actions to allow other plugins to add their own settings to it. This example shows a custom action being called at the end of the form:

function markup_settings_menu() {

	Foo: <input id="foo" name="foo1" type="text" />
	Bar: <input id="bar" name="bar1" type="text" />


	do_action( 'myplugin_after_form_settings' );

So now another plugin can register a callback for the custom myplugin_after_form_settings action and inject new settings:

function add_form_settings() {

	New 1: <input id="new_setting" name="new_settings" type="text" />
	New 2: <input id="new_setting2" name="new_setting2" type="text" />

add_action( 'myplugin_after_form_settings', 'add_form_settings' );

Creating an Extensible Custom Post TypeCustom Post Type WordPress can hold and display many different types of content. A single item of such a content is generally called a post, although post is also a specific post type. Custom Post Types gives your site the ability to have templated posts, to simplify the concept.

In this example, when the new post type is registered, the parameters that define it are passed through a filter, so another plugin can change them before the post type is created.

function myplugin_create_post_type() {
	$post_type_params = array( /* ... */ );

		apply_filters( 'myplugin_post_type_params', $post_type_params ),

The plugin that wants to modify the post type can then register a callback function for the custom myplugin_post_type_params filter that was created above. In this case, the callback is changing the post type from a flat type to a hierarchical one.

function change_post_type_params( $post_type_params ) {
	$post_type_params['hierarchical'] = true;
	return $post_type_params;
add_filter( 'myplugin_post_type_params', 'change_post_type_params' );

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