Page cache plugins

Last updated Oct 3, 20264 min read

A page cache stores finished pages. When you change something that appears on many pages (a phone number in Global Data, an options page value, a field group), the cached pages would keep showing the old value. Mass Custom Fields therefore asks your cache plugin to clear its pages after such changes. This is free and on by default.

Supported caches

The plugin calls only each product's public purge function or action. A cache is used only while it is active.

Cache	Purging a list of URLs	Purging everything
WP Rocket	`rocket_clean_files()` with the URLs	`rocket_clean_domain()`
LiteSpeed Cache	one `litespeed_purge_url` per URL	`litespeed_purge_all`
W3 Total Cache	`w3tc_flush_url()` per URL	`w3tc_flush_all()`
WP Super Cache	`wpsc_delete_url_cache()` per URL (1.7 or newer); older versions clear everything	`wp_cache_clear_cache()`
WP Fastest Cache	clears everything (it documents no per-URL purge)	`wpfc_clear_all_cache`
SiteGround Speed Optimizer	`sg_cachepress_purge_cache()` per URL	`sg_cachepress_purge_everything()` (or `sg_cachepress_purge_cache()`)
Breeze	clears everything (no per-URL action)	`breeze_clear_all_cache`
WP Engine	clears everything	its memcached and Varnish purge

Several active caches are all asked. Cloudflare (including APO) and Kinsta have no public purge function this plugin can call and are not supported; Cloudflare APO normally follows your page cache plugin's purge.

What triggers a purge

Change	What is cleared
An options page is saved, or an options value is written with `wpmcf_update_option_field()`	Everything
Global Data is saved	Everything
A field group is created, changed or deleted	Everything
A post value is written with `wpmcf_update_field()`	That post's URL
Programmatic SEO: a run finishes with created, updated or removed pages; generated pages or a task are deleted; a page template post is saved	Everything
Programmatic SEO: a single page is edited, enriched by AI or its row changes	That page's URL (everything when the page is not known)
Programmatic SEO: a page is converted into a post	That post's URL

Not triggered by this plugin: saving a post on the normal edit screen. Cache plugins already clear a post when it is saved, so only the plugin-wide changes above need this help. A field group only changes (and clears) when you save the group itself, not when editors save posts.

A front-end page that prints a field of the signed-in visitor through a wp.user_… variable is flagged as not cacheable (DONOTCACHEPAGE and no-cache headers), so a cache does not keep one person's data for everyone.

How requests are sent

Requests are collected during the request and sent once when it ends, so saving 500 items clears the cache once, not 500 times.
URLs are de-duplicated. Only http and https addresses are used.
A request for everything wins over a list of URLs.
More than 200 URLs are turned into one purge of everything, which is cheaper and safer.
If an adapter fails (for example the cache plugin changed its API), the error is logged under WPM Fields › Settings › Health and the other caches are still cleared. A failing cache never breaks the save that triggered it.

Settings

Open WPM Fields › Settings › General. The Page caches card has:

Control	Default	Effect
Clear page caches after changes	On	Asks your cache plugin to clear its pages after options pages, Global Data, field groups or generated pages change. Off stops all automatic purging.
Detected:		One badge per active supported cache, or "No supported cache plugin is active."

Save the settings after changing the toggle.

For developers

Hook	Type	Purpose
`wpmcf/cache/purge`	action	Request a purge: pass a URL or a list of URLs; pass nothing (or an empty list) for everything.
`wpmcf/cache/purge_post`	action	Request a purge of one post's permalink (post id).
`wpmcf/cache/purged`	action	Fires after the batch was sent: the URLs and `true` when everything was cleared.
`wpmcf/cache/enabled`	filter	Overrides the setting (`true` or `false`).
`wpmcf/cache/adapters`	filter	Add or remove cache adapters (objects implementing the plugin's `CacheAdapter` interface).

Troubleshooting

The cache is not cleared after I changed a field value on a post. That is left to the cache plugin, which clears a post on save. Check that the cache plugin does so, or call do_action( 'wpmcf/cache/purge_post', $post_id ).
"No supported cache plugin is active." Your cache is not on the list above, or it is inactive. Server-level caches (Cloudflare, Kinsta, Nginx FastCGI cache) must be purged by their own tools.
Pages are still stale after a change. A browser cache or a CDN in front of the page cache may hold a copy. Check WPM Fields › Settings › Health for a logged adapter error, and make sure the toggle is on.
Purges are too aggressive. A change to a field group clears everything on purpose. Turn the toggle off if you prefer to clear the cache yourself.

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