Clearing the Cache Dynamically

Rapid Cache automatically handles updating the cache in many scenarios, such as when you publish a new post, or when you change your WordPress theme. However, there may be scenarios where you need to have finer control over when the cache is cleared, such as when a plugin or theme does not include support for WordPress caching plugins.

The following examples use the WordPress API hooks and filters system to call a custom function that itself will call the Rapid Cache API to clear the cache when a specific event occurs.

How to use the code examples

While you can add this code to your theme's functions.php file or use a Functionality Plugin, we recommend using a WordPress Must-Use Plugin by creating a file like wp-content/mu-plugins/rc-clear-cache.php and then adding the necessary PHP code (note that if the mu-plugins directory doesn't exist, you should create it).

What follows are a few examples of how you can clear the cache dynamically.

Examples using WordPress Hooks/Filters API

Clear entire cache when saving any post

If you want to clear the cache every time a post is saved or updated (i.e., when the save_post action is fired), you can use the following.

add_action( 'save_post', 'my_custom_clear_cache', 10, 1 );

function my_custom_clear_cache( ) {
    rapidcache_clear_cache();
}

Clear page cache when Custom Post Type is saved

Using the save_post_{$post_type} hook, which is fired whenever that custom post type is created or updated (see docs), you can use something like the following to clear the cache for a given page whenever a post with that custom post type is saved.

add_action( 'save_post_my-custom-post-type', 'clear_cache_for_page_id_5', 10, 1 );

function clear_cache_for_page_id_5( ) {
	rapidcache_clear_post_cache(5); // Clears cache for Post ID 5
}

You'll want to change 5 to the ID of the Page/Post whose cache you'd like to clear when that custom post type is saved, and you'll want to change my-custom-post-type to the actual name of your Custom Post Type.

Clear a specific URL cache when saving any post

Using the save_post hook, which is fired whenever a post created or updated (see docs), you can use something like the following to clear the cache for a given URL on your site.

add_action( 'save_post', 'clear_cache_for_page_url', 10, 1 );

function clear_cache_for_page_url( ) {
	rapidcache_clear_url_cache('http://example.com/sample-page/'); // Clears cache for page with URL http://example.com/sample-page/
}

You'll want to change http://example.com/sample-page/ to the URL of the Page/Post whose cache you'd like to clear. Note that you can also use the Watered-Down Regex Syntax in this URL.

Clear a specific page cache when saving any post

Using the save_post hook, which is fired whenever a post created or updated (see docs), you can use something like the following to clear the cache for a given page.

add_action( 'save_post', 'clear_cache_for_page_id_5', 10, 1 );

function clear_cache_for_page_id_5( ) {
	rapidcache_clear_post_cache(5); // Clears cache for Post ID 5
}

You'll want to change 5 to the ID of the Page/Post whose cache you'd like to clear.

Scheduling Custom Clear Cache Events

If you need to schedule a custom clear cache event to occur at a recurring time, you can use the WP Crontrol plugin to add a custom PHP Cron Event that makes one or more Rapid Cache API calls at a specified interval. After installing WP Crontrol, visit Dashboard → Tools → Cron Events → Add PHP Cron Event to add a new cron event.

Using the Rapid Cache API Class

If you need to call the Rapid Cache API from another PHP file, you will first need to load the WordPress framework (via wp-load.php). See the examples below.

<?php
// Load WordPress framework
require_once dirname(__FILE__).'/wp-load.php';

// Any of these API calls can now be made from this PHP file
rapidcache_clear_cache(); // Clear current site cache
rapidcache_clear_post_cache($post_id);  // Clear single post cache
rapidcache_clear_url_cache($url); // Clear url cache
rapidcache_wipe_cache();  // Clear entire cache (all sites if multisite)
rapidcache_purge_expired_cache(); // Clear only the expired cache files, leaving the valid intact.
rapidcache_get_version(); // Returns the plugin version
rapidcache_get_options(); // Returns the saved plugin options