Cache

Cache is a class found under Phalcon\Cache directory. It helps in accessing frequently used data at much faster rate. Phalcon\Cache is written in C Programming language and reduce overhead.

When to implement Cache?

When we are frequently using complex calculations that returns the same result.
When we are using many helpers and the output generated is always the same.
When we are accessing database data constantly and its data rarely changes.

Caching process is divided into 2 parts:

1) Frontend: Frontend checks whether a key has expired or not. Also perform additional transformations to the data before storing and after retrieving them from the backend.

2) Backend: Backend part is responsible for communicating, reading or writing the data required by the frontend.

Implementation

Below code provide basic caching process for 2 days cache by implementing frontend and backend adapters.

<?php

use Phalcon\Cache\Backend\File as BackFile;
use Phalcon\Cache\Frontend\Data as FrontData;

// Create an Output frontend. Cache the files for 2 days
$frontCache = new FrontData(
    [
        'lifetime' => 172800,
    ]
);

// Create the component that will cache from the 'Output' to a 'File' backend
// Set the cache file directory - it's important to keep the '/' at the end of
// the value for the folder
$cache = new BackFile(
    $frontCache,
    [
        'cacheDir' => '../app/cache/',
    ]
);
?>

Frontend Adapters

Adapter	Description
Phalcon\Cache\Frontend\Output	Read input data from standard PHP output.
Phalcon\Cache\Frontend\Data	It is used to cache any kind of PHP data (big arrays, objects, text, etc). Data is serialized before stored in the backend.
Phalcon\Cache\Frontend\Base64	It's used to cache binary data. The data is serialized using base64_encode before be stored in the backend.
Phalcon\Cache\Frontend\Json	Data is encoded in JSON before be stored in the backend. Decoded after be retrieved. This frontend is useful to share data with other languages or frameworks.
Phalcon\Cache\Frontend\Igbinary	It is used to cache any kind of PHP data (big arrays, objects, text, etc). Data is serialized using Igbinary before be stored in the backend.
Phalcon\Cache\Backend\Xcache	Stores data in XCache.
Phalcon\Cache\Backend\None	It is used to cache any kind of PHP data without serializing them.

Backend Adapters

Adapter	Description	Info	Required Extension
Phalcon\Cache\Backend\Apc	Stores data to the Alternative PHP Cache (APC).	APC	APC
Phalcon\Cache\Backend\Apcu	Stores data to the APCu (APC without opcode caching)	APCu	APCu
Phalcon\Cache\Backend\File	Stores data to local plain files
Phalcon\Cache\Backend\Mongo	Stores data to Mongo Database.	MongoDB	MongoDB
Phalcon\Cache\Backend\Redis	Stores data in Redis	Redis	Redis
Phalcon\Cache\Backend\Xcache	Stores data in XCache.	XCache	XCache
Phalcon\Cache\Backend\Memcache	Stores data to a memcached server.	Memcache	Memcache