<?php
/**
*
*/
abstract class Loco_data_Transient extends Loco_data_Serializable {
/**
* Lifespan to persist object in transient cache
* @var int seconds
*/
private $ttl = 0;
/**
* Get short suffix for use as end of cache key.
* DB allows 191 characters including "_transient_timeout_loco_" prefix, leaving 167 bytes
* @return string
*/
abstract public function getKey();
/**
* Persist object in WordPress cache
* @param int
* @param bool
* @return Loco_data_Transient
*/
public function persist(){
$key = 'loco_'.$this->getKey();
set_transient( $key, $this->getSerializable(), $this->ttl );
$this->clean();
return $this;
}
/**
* Retrieve and unserialize this object from WordPress transient cache
* @return bool whether object existed in cache
*/
public function fetch(){
$key = 'loco_'.$this->getKey();
$data = get_transient( $key );
try {
$this->setUnserialized($data);
return true;
}
catch( InvalidArgumentException $e ){
return false;
}
}
/**
* @param int
* @return self
*/
public function setLifespan( $ttl ){
$this->ttl = (int) $ttl;
return $this;
}
/**
* Set keep-alive interval
* @param int
* @return self
*/
public function keepAlive( $timeout ){
$time = $this->getTimestamp();
// legacy objects (with ttl=0) had no timestamp, so will always be touched.
// make dirty if this number of seconds has elapsed since last persisted.
if( time() > ( $time + $timeout ) ){
$this->touch()->persistLazily();
}
return $this;
}
}