Tag Interop Laravel Package

Getting Started

Start by installing the package via Composer (composer require cache/tag-interop). This package provides only interfaces—no concrete implementations—so it must be used alongside a cache pool that supports tagging (e.g., cache/file-filesystem, cache/array-adapter with tagging support, or custom pools implementing the interfaces). First, locate the two core interfaces: Cache\TagInterop<TaggableCacheItemPoolInterface> (extends PSR-6’s CacheItemPoolInterface) and Cache\TagInterop<TaggableCacheItemInterface> (extends PSR-6’s CacheItemInterface). These extend PSR-6 with optional tagging capabilities (tag(), invalidateTags()), enabling developers to build tag-based cache invalidation strategies—e.g., busting all cache items related to a "user:123" or "product:456" tag on updates.

Implementation Patterns

• Conditional Tagging: In repositories or services, wrap cache saves with ->tag('entity:type:123') before save().
• Bulk Invalidation: Use invalidateTags(['user:123', 'theme:dark']) on a tagged pool to clear related entries without knowing individual keys.
• PSR-6 + Tagging Hybrid: Leverage tagged pools in Laravel via custom Cache\Store implementations or in Symfony with cache.adapter.taggable services—integrate via factory or decorator.
• Dependency Injection: Inject TaggableCacheItemPoolInterface type-hinted services for testability; mock tagging behavior in unit tests.
• PSR-6/PSR-16 Bridge: For hybrid systems, adapt PSR-16 cache calls into tagged workflows by securing a tagged pool for write-heavy paths (e.g., API responses, rendered views).

Gotchas and Tips

• ⚠️ No default implementation: This package only defines interfaces. Confusingly, composer require cache/tag-interop alone won’t give tagging behavior—you must pair it with a tagged-capable pool (e.g., php-cache/file-filesystem v1.2+).
• ⚠️ PSR-6 Compatibility: Though tagged pools extend PSR-6, not all PSR-6 implementations support tagging—always verify instanceof TaggableCacheItemPoolInterface before calling tag() or invalidateTags().
• Debugging: Use var_dump(get_class($pool)) to confirm the pool implements the interface; invalidateTags() silently fails on non-tagged pools—check logs for null returns.
• Extension Points: For custom pools, implement both interfaces (e.g., class MyPool implements TaggableCacheItemPoolInterface) and manage tag→keys mappings manually in save(), invalidateTags().
• ⚠️ PHP 8 Support: Version 1.1.0+ is required for PHP 8+—older versions use PHPDoc for return types and may cause autoloading issues in modern projects.
• Future-proofing: Since these are intended for PSR, prefer the Cache\TagInterop\ namespace (not Cache\Taggable\*)—the codebase is stable but deprecated in favor of upcoming PSR-6 extensions.