FluentCache

A fluent cache builder API for PSR-16 compatible cache components

Requirements

• PHP 7.4 (main, 2.x)

Installation

Use Composer. There are two ways to add FluentCache to your project.

From the composer CLI:

./composer.phar require modethirteen/fluent-cache

Or add modethirteen/fluent-cache to your project's composer.json:

{
    "require": {
        "modethirteen/fluent-cache": "dev-main"
    }
}

dev-main is the main development branch. If you are using FluentCache in a production environment, it is advised that you use a stable release.

Assuming you have setup Composer's autoloader, FluentCache can be found in the modethirteen\FluentCache\ namespace.

Usage

The principal type that FluentCache provides is CacheBuilder. CacheBuilder is an immutable object that takes references to a cache and anonymous functions to generate a cache key, build cacheable objects, validate results, and hook an event dispatcher.

CacheBuilder handles the responsibility for, and obfuscates, the steps required to orchestrate the most common scenario for handling cached data:

• Check the cache for an object
  • If miss, build an object, set it in the cache, and return the object
  • If hit, return the object

Managing these steps, choosing what to profile, when to validate, or other cache-specific decision-making isn't the responsibility of the calling code: the caller just wants to get an object, it shouldn't care if it comes from a cache, if the data is stale, or the object is built for the first time. CacheBuilder separates this concern and encapsulates it, exposing custom logic hooks for reasonable flexibility.

class Memcache implements \Psr\SimpleCache\CacheInterface {}

class Dispatcher implements \Psr\EventDispatcher\EventDispatcherInterface {}

$result = (new CacheBuilder())
    ->withCache(new Memcache(), function() : ?string {

        // generate a cache key - if null is returned, then the cache will be ignored
        return 'foo';
    })
    ->withCacheLifespanBuilder(function($result) : int {

        // what is the ttl for objects set in the cache?
        return 1500;
    })
    ->withCacheValidator(function($result) : bool {

        // assert that cached object is valid when fetched
        if(!($result instanceof Bar)) {
            return false;
        }
        return $result->someProperty === 'some value';
    })
    ->withBuilder(function() : object {

        // build a cacheable object if cache miss
        return new Bar();
    })
     ->withBuildValidator(function($result) : object {

        // assert that post-cache miss built object is valid
        return $result instanceof Bar;
    })

    // send cache and build stage events to trigger downstream actions such as profiling
    ->withEventDispatcher(new Dispatcher())

    // ...or set a lazy dispatcher to initialize when we attempt to fetch an object
    ->withLazyEventDispatcher(function(CacheBuilder $this) : EventDispatcherInterface {
        return new Dispatcher();
    })
 
    // set a custom identifier to track this cache session in downstream event processors
    // ...session ids are automatically generated if not provided
    // ...session ids are re-generated everytime the immutable cache builder is cloned 
    ->withSessionId('123')
 
    // fetch object from cache or build it and set it in the cache - the caller doesn't care!
    ->get();