cache.md

description	The FileCache service provides a simple interface for reading and writing from the application's cache directory.

FileCache

The FileCache service provides an API for writing to, and reading from a dedicated cache directory on disk.

The FileCache service is loaded using the Factory:

use Nails\Common\Service\FileCache;
use Nails\Factory;

/** @var FileCache $oFileCache */
$oFileCache = Factory::service('FileCache');

Private Cache

The private cache is a cache which is designed to be private to the application, which no direct access via a URL.

// Returns the cache directory
$oFileCache->getDir();

$sCacheKey = 'my-cahced-item';
$sData     = 'Some data to write';

// Write a new item to the cache
$oFileCache->write($sData, $sCacheKey);

// Read an existing item from the cache
$oFileCache->read($sCacheKey);

// Determine whether a cache key exists
$oFileCache->exists($sCacheKey);

Items returned from the cache are instances of Nails\Common\Resource\FileCache\Item - these objects wrap the item on disk but do not access the file until cast as a string, allowing you to efficiently read cache items without having to hit the disk until actually required.

Public Cache

The public cache has an identical interface to the private cache, however it is exposed to the public via a URL and adds the getUrl(string $sKey = null): string method.

Access the public cache via the FileCache service's public() method:

$oPublicCache = $oFileCache->public();

$sCacheKey = 'my-cahced-item';
$sData     = 'Some data to write';

// Write a new item to the cache
$oPublicCache->write($sData, $sCacheKey);

// Read an existing item from the cache
$oPublicCache->read($sCacheKey);

// Determine whether a cache key exists
$oPublicCache->exists($sCacheKey);

// Get the item's URL
$oPublicCache->getUrl($sCacheKey);

{% hint style="info" %} If you need to change the URL for the public cache, perhaps to route via a CDN, then set the CACHE_PUBLIC_URL configuration option. {% endhint %}

Configuration

The following configuration options can be set to customise behaviour:

Option	Description	Default
CACHE_PRIVATE_DIR	The directory to use for the private cache.	./cache/private
CACHE_PUBLIC_DIR	The directory to use for the public cache.	./cache/public
CACHE_PUBLIC_URL	The base URL for items in the public cache.	/cache/public