berny/cache

Unified set of tools for common caching tasks

Berny\Cache

This library provides a unified set of tools for common caching tasks., _(*1)

, _(*2)

Features

Moves from the classic cache interface to a item interface., _(*3)

Instalation

From composer/packagist

• Add "berny/cache": "*@dev" to your composer.json file

From github

• Download the code into your project

Storage

You want to store your cached data somewhere, and this is where StorageInterface comes handy., _(*4)

Its only job is to create Items from keys through the getItem($key) method., _(*5)

Some implementations of this interface are:, _(*6)

• FilesystemStorage
• MemoryStorage
• DoctrineCacheAdapter

Item

Items allow management of ONE key inside a given Storage. You can:, _(*7)

• key(): Get the item's key
• get(): Get its cached value (if not missed the cache)
• set($value): Set the cached value
• miss(): Check if it missed the cache
• remove(): Clear it

Example

function cacheComplexFunction(ItemInterface $item, Closure $complex)
{
    if ($item->miss()) {
        $value = $complex($item->key());
        $item->set($value);
    }
    return $item->get();
}

$storage = new MemoryStorage();
$result = cacheComplexFunction($storage->getItem('key'), complexCalculation);

Cache

The main brain is Cache, a concrete class which receives a StorageInterface (and optionally a StrategyInterface) to proxy all requests through it. It defines:, _(*8)

• get($key, $default = null): Our plain get by key, returning $default on cache misses.
• getOrSet($key, $value): Gets cached values by key, storing and returning $value on cache misses.
• getOrLazySet($key, $callback): Same as getOrSet but with lazy evaluation of $callback on cache misses.
• set($key, $value): No secrets, a vanilla set by key.
• remove($key): Remove items only when not missed the cache.
• getItem($key): Return the ItemInterface created by the underlying StorageInterface.

Example

// Storage is any StorageInterface implementation
$cache = new Cache($storage);

$result = $cache->get('key_1'); // null on cache misses
$result = $cache->get('key_2', 'default'); // 'default' on cache misses
$result = $cache->getOrSet('key_3', 'value'); // 'value' stored on cache misses
$result = $cache->getOrLazySet('key_4', $callback); // $callback called only on cache misses

Strategy

Implement the StrategyInterface to automate generation of concrete keys from any user-domain ones. This allows for automatic cache invalidation., _(*9)

If injected into Cache, keys go first through this object before calling setItem($key)., _(*10)

Implementations:, _(*11)

• FilesystemStrategy: Treats keys as path filenames. Returns a key with last modified time to invalidate cache entries on file changes.

Example

$path = __DIR__ . '/to-do/';
$strategy = new FilesystemStrategy();
// Storage is any StorageInterface implementation
$cache = new Cache($storage, $strategy);
// Callback only called the first time and every time the $path content changes
$cache->getOrLazySet($path, $callback);