* @link http://getkirby.com
* @copyright Bastian Allgeier
* @license http://www.opensource.org/licenses/mit-license.php MIT License
*/
abstract class Driver {
// stores all options for the driver
protected $options = array();
/**
* Set all parameters which are needed to connect to the cache storage
*
* @param array $params
*/
public function __construct($params = array()) {}
/**
* Write an item to the cache for a given number of minutes.
*
*
* // Put an item in the cache for 15 minutes
* Cache::set('value', 'my value', 15);
*
*
* @param string $key
* @param mixed $value
* @param int $minutes
* @return void
*/
public abstract function set($key, $value, $minutes = null);
/**
* Private method to retrieve the cache value
* This needs to be defined by the driver
*
* @param string $key
* @return object Value
*/
public abstract function retrieve($key);
/**
* Get an item from the cache.
*
*
* // Get an item from the cache driver
* $value = Cache::get('value');
*
* // Return a default value if the requested item isn't cached
* $value = Cache::get('value', 'default value');
*
*
* @param string $key
* @param mixed $default
* @return mixed
*/
public function get($key, $default = null) {
// get the Value
$value = $this->retrieve($key);
// check for a valid cache value
if(!is_a($value, 'Cache\\Value')) return $default;
// remove the item if it is expired
if(time() > $value->expires()) {
$this->remove($key);
return $default;
}
// get the pure value
$cache = $value->value();
// return the cache value or the default
return (!is_null($cache)) ? $cache : $default;
}
/**
* Calculates the expiration timestamp
*
* @param int $minutes
* @return int
*/
protected function expiration($minutes = null) {
// keep forever if minutes are not defined
if(is_null($minutes)) $minutes = 2628000;
// calculate the time
return time() + ($minutes * 60);
}
/**
* Checks when an item in the cache expires
*
* @param string $key
* @return mixed
*/
public function expires($key) {
// get the Value object
$value = $this->retrieve($key);
// check for a valid Value object
if(!is_a($value, 'Cache\\Value')) return false;
// return the expires timestamp
return $value->expires();
}
/**
* Checks if an item in the cache is expired
*
* @param string $key
* @return int
*/
public function expired($key) {
return $this->expires($key) <= time();
}
/**
* Checks when the cache has been created
*
* @param string $key
* @return mixed
*/
public function created($key) {
// get the Value object
$value = $this->retrieve($key);
// check for a valid Value object
if(!is_a($value, 'Cache\\Value')) return false;
// return the expires timestamp
return $value->created();
}
/**
* Alternate version for cache::created($key)
*/
public function modified($key) {
return static::created($key);
}
/**
* An array with value, created timestamp and expires timestamp
*
* @param mixed $value The value, which should be cached
* @param int $minutes The number of minutes before expiration
* @return array
*/
protected function value($value, $minutes) {
return new Value($value, $minutes);
}
/**
* Determine if an item exists in the cache.
*
* @param string $key
* @return boolean
*/
public function exists($key) {
return !$this->expired($key);
}
/**
* Remove an item from the cache
*
* @param string $key
* @return boolean
*/
public abstract function remove($key);
/**
* Flush the entire cache
*
* @return boolean
*/
public abstract function flush();
}