OPcache & Memcached Manager

A WordPress plugin for monitoring and managing OPcache and Memcached from wp-admin, with matching WP-CLI commands. Optionally installs a Memcached-backed object cache and/or a full-page cache.

This plugin is not on WordPress.org — it updates itself from this repository's GitHub Releases through the normal plugin update UI.

What it does

A single Cache Manager screen (Administrators only) showing:

• OPcache — enabled state, memory usage, hit rate, cached script/key counts, cache-full and restart status. Reset the whole cache, or invalidate one file.
• Memcached — per-server reachability and stats (items, memory, hit rate, connections, evictions) for a configurable server pool, and whether Memcached is currently acting as WordPress's object cache. Flush the pool directly, or flush the WP object cache.
• Object cache drop-in — install/remove a Memcached-backed WP_Object_Cache (wp-content/object-cache.php).
• Page cache — install/remove a Memcached-backed full-page cache (wp-content/advanced-cache.php), with a TTL, configurable exclusion patterns, and targeted purging on content changes.

There's also a "Clear all caches" action (button, WP-CLI command, and toolbar entry) that clears all four at once, and a "Cache" menu in the admin toolbar with stats and clear controls for administrators.

The two drop-ins are optional and independent. Full detail on how the page cache makes its decisions and what it purges is in readme.txt.

Requirements

• WordPress 6.5+
• PHP 7.4+
• The PHP memcached extension for the Memcached features; the Zend OPcache extension for the OPcache features. Each section degrades gracefully with a clear message when its extension is missing.

Installation

1. Download opcache-memcached-manager.zip from the latest release.
2. Plugins → Add New → Upload Plugin, or unzip into wp-content/plugins/.
3. Activate. Configure the Memcached server pool under Cache Manager.

Once installed, new releases appear in Plugins → Installed Plugins like any other update.

Installing from a plain git clone also works, but the version will read {{VERSION}} until a build stamps it (see Releases below), and the update check stays disabled while that placeholder is in place.

WP-CLI

wp cache-manager clear-all

wp cache-manager opcache status
wp cache-manager opcache clear
wp cache-manager opcache invalidate <file>

wp cache-manager memcached status
wp cache-manager memcached flush
wp cache-manager memcached flush-object-cache
wp cache-manager memcached install-dropin [--overwrite]
wp cache-manager memcached remove-dropin

wp cache-manager pagecache status
wp cache-manager pagecache purge
wp cache-manager pagecache purge-url <url>
wp cache-manager pagecache install-dropin [--overwrite]
wp cache-manager pagecache remove-dropin

All commands require an administrator (the manage_options capability).

Development

composer install
composer test        # PHPUnit — plain unit tests, no WordPress bootstrap

The test suite (tests/) covers the pure logic: the page-cache cache-key builder, the request-eligibility rules, and the Memcached server-list parser. tests/bootstrap.php shims the few WordPress functions those units touch, so the tests run without a WordPress install. CI runs them on PHP 7.4 through 8.3.

Runtime code has no dependencies — composer.json carries dev tooling only, and classes load through a require_once chain in the main plugin file rather than an autoloader.

The drop-in key-sync invariant

omm_pagecache_build_key() in dropins/advanced-cache-dropin.php runs before WordPress loads; OMM_PageCache::build_key() in includes/class-omm-pagecache.php rebuilds the same key when purging. They must produce identical keys or purges silently stop matching. PageCacheKeyTest locks this — run it after touching either.

More conventions (security baseline, when to bump a drop-in version, etc.) are in AGENTS.md.

Releases

The plugin header, OMM_VERSION, and the readme.txt stable tag carry a {{VERSION}} placeholder in source — never a real number. Pushing a tag runs .github/workflows/release.yml, which runs the tests, stamps the tag into those placeholders, packages the plugin using .distignore as the exclude list, and attaches opcache-memcached-manager.zip to the GitHub Release.

git tag 1.3.0
git push origin 1.3.0

Changelog

See CHANGELOG.md.

License

GPL-2.0-or-later.