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Purge Swift Performance Cache Programmatically in WordPress

First share in 2022. As promised, let me share the coding way to clear Swift Performance cache in WordPress.

Swift Performance is my another favorite caching plugin in WordPress. Usually I will use it if the WordPress site hosted on non Litespeed server, it works beautiful and perfectly on Nginx. You can try the free Swift Performance Lite from WordPress repository.

Free version – Swift Performance Lite

Trigger The Purge

If you dig into the Swift Performance code, you could use the clear_all_cache() function as below.

<?php

if (class_exists('Swift_Performance_Cache')) {
	Swift_Performance_Cache::clear_all_cache();
}

?>

If you wrap the above code into a shortcode and execute it, you should be able to see the Swift Performance warmup table showing missing cache for all links, which means you successfully triggered the purge!

Warmup table showing all caches cleared

Remove and Rebuild Warmup Table

It might be a case that you need to rebuild the warmup table in Swift Performance. Just have a look to the codes below.

<?php

// Remove the Swift Performance Warmup Table
global $wpdb;
$wpdb->query('DROP TABLE IF EXISTS ' . SWIFT_PERFORMANCE_TABLE_PREFIX . 'warmup');
delete_option(SWIFT_PERFORMANCE_TABLE_PREFIX . 'db_version');

// Remove the transient so we can prebuild the url again
delete_transient('swift_performance_initial_prebuild_links');

?>

Now, let’s rebuild the warmup table.

<?php

if (class_exists('Swift_Performance_Cache')) {
	Swift_Performance::db_install();
	Swift_Performance::get_prebuild_urls();
}

?>

Bundle Up As Single Function

After understand the concepts and simple functions above, let’s bundle it up. And I will execute this function to my scheduled WP Cron as per my last tutorial.

<?php

// Hook on my daily scheduled WP Cronjob, which will be running on 00:00:05 daily
add_action( 'itchycode_daily','clear_swift_performance_cache' );

function clear_swift_performance_cache() {
	if (class_exists('Swift_Performance_Cache')) {
		global $wpdb;
		$wpdb->query('DROP TABLE IF EXISTS ' . SWIFT_PERFORMANCE_TABLE_PREFIX . 'warmup');
		delete_option(SWIFT_PERFORMANCE_TABLE_PREFIX . 'db_version');
		delete_transient('swift_performance_initial_prebuild_links');
		Swift_Performance::db_install();
		Swift_Performance_Cache::clear_all_cache();
		Swift_Performance::get_prebuild_urls();
	}
}

?>

Summary

Swift Performance and LiteSpeed Cache are my preferred caching plugin. It’s my pleasure if this article could give a help on your WordPress website.

WordPress functions / hooks being used this example:

  • Swift_Performance_Cache::clear_all_cache()
  • Swift_Performance::db_install()
  • Swift_Performance::get_prebuild_urls()
  • About Author

    I like to solve problems by coding. I like websites, web applications and everything viewable from browser. Knowledge sharing can grows my confidence. A simple "thank you" will make my day :)
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