Usage

Available methods

Method	Backed by	Purpose
remember( $key, $callback, $group, $expiry )	Object cache	Read, or compute + cache on miss.
forget( $key, $group, $default )	Object cache	Read then delete; return $default on miss.
persist( $key, $callback, $site_wide, $expiry )	Transients	Read, or compute + cache on miss.
cease( $key, $site_wide, $default )	Transients	Read then delete; return $default on miss.
flush_group( $group )	Object cache	Invalidate every entry in a group.
flush()	Object cache	Flush the entire object cache. Last resort.
object_cache() / transient_cache()	—	Access the underlying driver for finer-grained control.

Every callback-based helper checks the callback return with is_wp_error() and skips caching when a WP_Error is returned, so a transient API failure is not memorised.

remember() — object-cache read-through

$cache = \DuckDev\Cache\Cache::get_instance( 'my_plugin' );

$posts = $cache->remember( 'latest_posts', function () {
    return new WP_Query( array(
        'posts_per_page' => 5,
        'orderby'        => 'post_date',
        'order'          => 'desc',
    ) );
}, 'queries', HOUR_IN_SECONDS );

Unlike a naive wp_cache_get()-then-fall-back pattern, remember() distinguishes a legitimately cached 0, '', [], or false from a true miss — the callback only runs when nothing was cached.

forget() — one-shot read

$error = $cache->forget( 'form_errors', 'flash', false );

if ( $error ) {
    echo 'An error occurred: ' . esc_html( $error );
}

persist() — transient read-through

$cache->persist( 'latest_tweets_' . $user_id, function () use ( $user_id ) {
    return get_latest_tweets_for_user( $user_id );
}, false, 15 * MINUTE_IN_SECONDS );

Pass true for the third argument to use site-wide (multisite) transients.

TIP

Transients use boolean false as the miss sentinel, so a legitimately cached false value is indistinguishable from a miss. Reach for remember() if you need to cache false.

flush_group()

$cache->flush_group( 'queries' );

On WP 6.1+ with a persistent object cache backend that advertises flush_group support (via wp_cache_supports( 'flush_group' )), this delegates directly to wp_cache_flush_group(). Otherwise it falls back to incrementing a per-group version sentinel — old entries become unreadable on next access without touching the rest of the object cache.

Filters

Filter	Arguments	Use
{prefix}_can_cache	bool $enabled, string $type	Return false to disable caching. $type is 'object' or 'transient' so the two can be toggled independently.

Disabling caching for debugging

add_filter( 'my_plugin_can_cache', '__return_false' );