What is pca?

pca is an abstraction layer for various caches like memcached. It provides a common basic set of operations and makes sure the results are uniform across the various backends. pca uses SimpleTest for unit tests.

Supported backends

• Alternative PHP Cache
• Filesystem backend (with checksumming to avoid cache corruption)
• Memcached
• PDO: mySQL, Postgres, sqlite, ... (see PDO drivers)

License

pca is released into the public domain, see LICENSE.

Loading a backend

For a full list of backends and their configuration options please take a look at the API documentation. For example, to use the memcached backend, you can use this code:

require_once('path/to/pca_dir/pca/pca.class.php');
$options = array('server' => array('host' => 'localhost'));
$cache = PCA::factory('memcache', $options);

You can also let pca guess the best possible cache backend to avoid confusing the users of your software with a shitload of configuration options:

require_once('path/to/pca_dir/pca/pca.class.php');
$cache = PCA::get_best_backend();

Storing, retrieving and manipulating values

Store a value for 1 hour:

$cache->set('foo', 'bar', 3600)

Check if a value exists:

if($cache->exists('foo'))
    echo 'Found "foo"';
else
    echo 'No "foo" for you';

Retrieve the value (returns null when the value is empty):

$cache->get('foo');

Add a value only if it does not exist yet:

if($cache->add('foo', 'new_bar'))
    echo 'Key "foo" did not exist yet, created it';
else
    echo 'Don\'t mess with the "foo"';

Delete a value:

$cache->delete('foo');

Other operations

Delete all cached data:

$cache->flush();

The Filesystem and PDO backends require garbage collection to delete values that have expired, so make sure that you periodically run it:

$cache->gc();