psr6_psr16_adapters.rst

Adapters For Interoperability between PSR-6 and PSR-16 Cache

Sometimes, you may have a Cache object that implements the PSR-16 standard, but need to pass it to an object that expects a :ref:`PSR-6 <cache-component-psr6-caching>` cache adapter. Or, you might have the opposite situation. The cache component contains two classes for bidirectional interoperability between PSR-6 and PSR-16 caches.

Using a PSR-16 Cache Object as a PSR-6 Cache

Suppose you want to work with a class that requires a PSR-6 Cache pool object. For example:

use Psr\Cache\CacheItemPoolInterface;

// just a made-up class for the example
class GitHubApiClient
{
    // ...

    // this requires a PSR-6 cache object
    public function __construct(CacheItemPoolInterface $cachePool)
    {
        // ...
    }
}

But, you already have a PSR-16 cache object, and you'd like to pass this to the class instead. No problem! The Cache component provides the :class:`Symfony\\Component\\Cache\\Adapter\\Psr16Adapter` class for exactly this use-case:

use Symfony\Component\Cache\Adapter\Psr16Adapter;

// $psr16Cache is the PSR-16 object that you want to use as a PSR-6 one

// a PSR-6 cache that uses your cache internally!
$psr6Cache = new Psr16Adapter($psr16Cache);

// now use this wherever you want
$githubApiClient = new GitHubApiClient($psr6Cache);

Using a PSR-6 Cache Object as a PSR-16 Cache

Suppose you want to work with a class that requires a PSR-16 Cache object. For example:

use Psr\SimpleCache\CacheInterface;

// just a made-up class for the example
class GitHubApiClient
{
    // ...

    // this requires a PSR-16 cache object
    public function __construct(CacheInterface $cache)
    {
        // ...
    }
}

But, you already have a PSR-6 cache pool object, and you'd like to pass this to the class instead. No problem! The Cache component provides the :class:`Symfony\\Component\\Cache\\Psr16Cache` class for exactly this use-case:

use Symfony\Component\Cache\Adapter\FilesystemAdapter;
use Symfony\Component\Cache\Psr16Cache;

// the PSR-6 cache object that you want to use
$psr6Cache = new FilesystemAdapter();

// a PSR-16 cache that uses your cache internally!
$psr16Cache = new Psr16Cache($psr6Cache);

// now use this wherever you want
$githubApiClient = new GitHubApiClient($psr16Cache);