Bypass CDN Caching using functions.php

Bypass CDN Caching using functions.php

<?php // Exclude this opening tag.

/**
 * The template_redirect action hook allows pre-template actions.
 * We set s-maxage to 0 to ensure CDNs fetch fresh content,
 * assuming the CDN respects existing headers.
 */
add_action('template_redirect', function () {
    header('cache-control: s-maxage=0');
});

Use Case

Imagine managing two WordPress sites: example.com and example.com/wp/, both are hosted on Cloudways with the Cloudflare Enterprise Addon.

However, an issue arises with Breeze caching. Breeze fails to purge Cloudflare's cache for the WordPress installation in the subdirectory example.com/wp/.^[1] Additionally, there's no direct way to deactivate the Cloudflare HTML cache specifically for the subdirectory.

On a positive note, Cloudflare does respect existing headers and allows an opportunity to modify the caching behaviour using the s-maxage directive. By implementing this workaround, we can bypass the Cloudflare Cache for the HTML while continuing to benefit from a Page Caching plugin such as Breeze.

Reference

1. https://wordpress.org/support/topic/doesnt-purge-cloudflare-addon-cache-for-subdirectory-based-wp/