Herd VIP

Shared cache-invalidation helpers for Herd WordPress VIP applications.

What it does

For public post types, this plugin purges the homepage, the changed post URL, and its post-type archive when content is created, updated, or deleted. It skips revisions and autosaves.

Every URL is purged from WordPress VIP using wpcom_vip_purge_edge_cache_for_url(). Cloudflare purging is optional: it runs only when both of these VIP environment variables are present:

• CLOUDFLARE_API_TOKEN — a Zone-scoped Cloudflare token with only Cache Purge permission.
• CLOUDFLARE_ZONE_ID — the zone ID for the configured domain.

Install

Install the plugin as an always-active plugin in each VIP codebase. For example, place this repository under client-mu-plugins/herd-vip/ and require it from a root-level loader file:

<?php
require_once WPMU_PLUGIN_DIR . '/herd-vip/herd-vip.php';

Alternatively, install it as a conventional plugin and activate it through WordPress.

Coding standards

The plugin is checked against the WordPress VIP Go standard, plus WordPress-Extra, WordPress-Docs, and PHPCompatibilityWP. The ruleset lives in .phpcs.xml.dist.

composer install
composer phpcs   # scan
composer phpcbf  # auto-fix
composer lint    # php -l

These are development dependencies only; vendor/ is not needed at runtime and should not be deployed.

Theme-specific URLs

Themes can extend the target list for dynamic content, such as a directory page populated by a custom post type:

add_filter(
    'herd_vip_cache_purge_urls',
    function ( $urls, $post, $context ) {
        if ( 'example-profile' !== $post->post_type ) {
            return $urls;
        }

        $urls[] = home_url( '/team/' );
        return $urls;
    },
    10,
    3
);

The filter receives the initial URL array, the WP_Post, and a context of create, update, or delete.

The herd_vip_should_purge_post filter can opt out of generic purges for a post when needed.