Flexa Cache

Flexa Cache intercepts every cacheable WordPress request and serves it from a pre-generated static HTML file, bypassing PHP and the database entirely. Optimization passes - HTML minify, CSS/JS combine, lazy load, defer - run on the buffer before the file is written, so every subsequent request gets the optimized version at zero per-request cost.

The admin - Settings, Cache stats, Purge controls, Preloader - is a single-page React app (Vite + TypeScript + Tailwind v4) talking to a namespaced REST API.

Three layers stack on top of each other, each acting before the previous one would have done its work.

The request-to-path algorithm in the drop-in mirrors Cache\Store::relative_path() byte-for-byte: lowercase host + sanitized URL path + trailing /index.html. Changing one requires changing both or cache hits silently miss.

// Before WordPress loads — no WP functions available.
if (!defined('WP_CACHE') || !WP_CACHE) return;

$path = build_cache_path($_SERVER['HTTP_HOST'], $_SERVER['REQUEST_URI']);

// Mobile-split: a 0-byte sentinel written by Engine::finalize()
// when the mobile_theme setting is on.
if (is_mobile_ua() && is_readable($path . '/.mobile-split')) {
    $file = $path . '/index-mobile.html';
} else {
    $file = $path . '/index.html';
}

if (is_readable($file)) {
    // Serve the static file and exit before WordPress boots.
    header('Content-Type: text/html; charset=UTF-8');
    readfile($file);
    exit;
}
// Fall through to WordPress.

1. Upload the flexa-cache folder to wp-content/plugins/ (or install the .zip from the Plugins screen).
2. Activate the plugin through the WordPress "Plugins" menu.
3. On activation the plugin copies advanced-cache.php to wp-content/advanced-cache.php and adds define('WP_CACHE', true); to wp-config.php (idempotent - safe to run multiple times).
4. Open Flexa Cache and flip on Enable caching.

All settings are stored as a single serialized array under the WordPress option key flexa_cache_settings. The REST API uses partial-diff saves: only changed keys are sent; the PHP Settings::sanitize() method merges them over the stored values.

All routes are registered under /wp-json/flexa-cache/v1/. Every route requires current_user_can('manage_options') and standard WordPress REST authentication (auth cookie + X-WP-Nonce from wp_create_nonce('wp_rest')).

fetch('/wp-json/flexa-cache/v1/cache/purge', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-WP-Nonce': wpApiSettings.nonce,
  },
  body: JSON.stringify({
    scope: 'url',
    url: 'https://example.com/blog/my-post/',
  }),
})
  .then(r => r.json())
  .then(console.log);

Flexa Cache exposes several slash-separated action and filter hooks so integrators can extend or gate behavior without modifying plugin files.

add_filter('flexa_cache/engine/is_cacheable', function (bool $cacheable): bool {
    // Never cache the /live-scores/ subtree.
    if (str_starts_with($_SERVER['REQUEST_URI'], '/live-scores/')) {
        return false;
    }
    return $cacheable;
});

Flexa Cache registers commands under the wp flexa-cache namespace. All commands route through the same shared PHP paths as the REST API and admin UI.

wp flexa-cache clear && wp flexa-cache preload start

Text domain flexa-cache. Both PHP strings (.mo) and the React admin JS strings (script-translation .json via wp_set_script_translations) are localisable. The catalog contains 138 strings (136 JS + 12 PHP).

Because wp i18n make-pot cannot parse .tsx/.ts files directly, the plugin ships scripts/extract-tsx-i18n.mjs - a Node script that emits a transient JS shim of every __(), _x() and _n() call. The shim is passed to make-pot and deleted afterwards. The full flow:

bash makepot.sh