Caching

Global Configuration¶

To use xPDO’s caching abilities, you’ll need to configure several global options to define caching options. Most importantly, you should define the xPDO::OPT_CACHE_PATH into the $options variable of the xPDO constructor. Set it to the absolute path you would like xPDO to write cache files to. This also provides a location for xPDO to write log files if configured to do so, which would require this file path to be defined even if no file-based caching was being utilized.

There are several additional global options that can be set if you wish to use something other than the default cache partition and provider.

• xPDO::OPT_CACHE_HANDLER - This defines a cache provider, or xPDOCache derivative class which implements xPDO caching methods. (default=xPDO\Cache\xPDOFileCache)
• xPDO::OPT_CACHE_KEY - This defines a cache partition, or an instance of the xPDOCache derivative class defined as the cache handler or provider. (default=default)
• xPDO::OPT_CACHE_EXPIRES - This defines a default cache expiration time in seconds for all cache partitions to use if not specifically configured themselves.(default=0)

Additional options are defined for specific cache providers.

Caching Providers and Partitions¶

xPDO supports extending the caching mechanism to different ‘caching providers’. The default provider, xPDOFileCache, is a file-based caching implementation.

The base class, xPDOCache, can be extended to create different cache providers, and users can configure xPDO via the xPDO::OPT_CACHE_HANDLER option to use a specific derived class.

A derived xPDOCache implementation must be in a package that is loaded by the constructor. You can use xPDO::OPT_BASE_PACKAGES to define such packages to preload or load it in your overridden constructor when extending the xPDO class.

Manipulation of the Cache¶

The $xpdo->cacheManager object, built from the xPDOCacheManager class, is accessible after calling $xpdo->getCacheManager().

A simple example script of setting data into a cache partition, then getting it, and deleting it, is as follows:

$str = 'My cached data.';
$xpdo->cacheManager->set('testdata', $str);

echo $xpdo->cacheManager->get('testdata');
// outputs: My cached data.

$xpdo->cacheManager->delete('testdata');

This uses the global cache configuration to set, retrieve, and remove a cache entry. This would be the default cache partition used by the xPDOCacheManager.

Utilizing Specific Cache Partitions¶

To target cache data in a specific partition, you will need to either pass a configuration defining the partition to each method call from xPDOCacheManager, or retrieve a specific cache provider partition and utilize it’s methods directly.

An example of passing the configuration to the xPDOCacheManager methods:

$cacheOptions = array(
    xPDO::OPT_CACHE_KEY => 'myCache',
    xPDO::OPT_CACHE_HANDLER => 'xPDO\\Cache\\xPDOAPCCache',
);

$xpdo->cacheManager->set('testdata', 'My cached data.', 0, $cacheOptions);

echo $xpdo->cacheManager->get('testdata', $cacheOptions);
// outputs: My cached data.

$xpdo->cacheManager->delete('testdata', $cacheOptions);

This would use an instance of xPDO\Cache\xPDOAPCCache. The partition key is used by xPDOCache::getCacheKey() to namespace entries within the provider.

An alternative approach is to get the specific cache partition itself and use it’s methods directly:

$myCache = $xpdo->cacheManager->getCacheProvider('myCache', array(
    xPDO::OPT_CACHE_KEY => 'myCache',
    xPDO::OPT_CACHE_HANDLER => 'xPDO\\Cache\\xPDOAPCCache',
));

$myCache->set('testdata', 'My cached data.');

echo $myCache->get('testdata');
// outputs: My cached data.

$myCache->delete('testdata');

See Also¶

• xPDOCacheManager

1. Caching Tutorial - Basic Snippets
2. Caching Tutorial - Lifetimes