WP Cache Helper — Overview

A small WordPress library that wraps the object cache and transient APIs with a callback-style remember() helper, group-flush support for the object cache (delegating to core's wp_cache_flush_group() on WP 6.1+ backends that support it, with a version-sentinel fallback for backends that don't), and per-prefix scoping so multiple consumers on the same site never collide.

Inspired by WP Cache Remember.

Why it exists

• Callback-style caching. remember() distinguishes a legitimately cached 0, '', [], or false from a true miss — the callback only runs when nothing was cached.
• Group flush without core support. Increments a per-group version sentinel so old entries become unreadable without touching the rest of the cache. On WP 6.1+ backends with native support, delegates straight to wp_cache_flush_group().
• Per-prefix scoping. Every key, group, and the {prefix}_can_cache filter is namespaced under the supplied prefix, so multiple consumers can't collide.

Architecture

src/
├── Cache.php                     # Container + entry point
├── Contracts/
│   ├── ObjectCacheInterface.php
│   └── TransientCacheInterface.php
├── Storage/
│   ├── ObjectCache.php           # wp_cache_* wrapper + native/fallback group flush
│   └── TransientCache.php        # (site_)transient wrapper
├── Support/
│   └── KeyPrefixer.php           # Shared key + group prefixing
└── Exceptions/
    └── CacheException.php

Services receive their collaborators by constructor injection so they can be unit-tested without WordPress in the loop. Construction has no side effects.