Memcached CakePHP CacheEngine

memcached.php

<?php

/**
 * Memcached storage engine for CakePHP
 * 
 * PHP versions 4 and 5
 * 
 * @author Ezra Pool <[email protected]>
 * @copyright BSD
 * @version 0.2.1
 */

/**
 * Memcached storage engine for cache.
 */
class MemcachedEngine extends CacheEngine{
/**
 * Memcache wrapper.
 *
 * @var Memcache
 * @access private
 */
  var $__Memcached = null;
  
/**
 * Settings
 *
 *  - servers = array of memcache servers, default => 127.0.0.1, 11211. If an
 *    array MemcacheEngine will use them as a pool.
 *  - compress = boolean, default => false
 *
 * @var array
 * @access public
 */
  var $settings = array();
  
/**
 * Initialize the Cache Engine
 *
 * Called automatically by the cache frontend
 * To reinitialize the settings call Cache::engine('EngineName', [optional] settings = array());
 *
 * @param array $setting array of setting for the engine
 * @return boolean True if the engine has been successfully initialized, false if not
 * @access public
 * @since 0.1
 * @author Ezra Pool <[email protected]>
 */
  function init($settings = array()){
    if(!class_exists('Memcached')){
      return false;
    }
    parent::init(array_merge(array(
        'engine' => 'Memcached',
        'prefix' => Inflector::slug(APP_DIR) . '_',
        'servers' => array(array(
          'host' => '127.0.0.1',
          'port'  => 11211,
          'weight' => 0,
        )),
        'compress'=> true,
        'persistent' => false,
        ), $settings)
    );
          
    if(!isset($this->__Memcached)){
      $return = false;
      if($this->settings['persistent']){
        $this->__Memcached =& new Memcached($this->settings['persistent']);
      }else{
        $this->__Memcached =& new Memcached();
      }

      $this->__Memcached->setOption(Memcached::OPT_COMPRESSION, $this->settings['compress']);

      //find out if the servers have already been added, extension does not check for dupes, so we have to!
      $servers = $this->__Memcached->getServerList();
      $newserverlist = array();
      foreach($this->settings['servers'] as $settingsserver){
        $found = false;
        foreach($servers as $server){
          if($server['host'] == $settingsserver[0] && $server['port'] == $settingsserver[1]){
            $found = true;
            break;
          }
        }
        if(!$found){
           $newserverlist[] = $settingsserver;
        }
      }

      if(empty($newserverlist) || $this->__Memcached->addServers($this->_parseServerList($newserverlist))){
        $return = true;
      }
      return $return;
    }
    return true;
  }
  /**
   * Parses the server address into the host/port.  Handles both IPv6 and IPv4
   * addresses
   *
   * @param string $server The server address string.
   * @return array Array containing host, port
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function _parseServerList($serverlist) {
    foreach($serverlist as &$server){
      if(!isset($server['host'])){
        $server['host'] = 'localhost';
      }
      if(!isset($server['port'])){
        $server['port'] = 11211;
      }
      if(!isset($server['weight'])){
        $server['weight'] = 0;
      }
    }
    return $serverlist;
  }
  
  /**
   * Write data for key into cache.  When using memcached as your cache engine
   * remember that the Memcached extension treats cache expiry times greater
   * than 30 days as a timestamp not an offset.
   *
   * @param string $key Identifier for the data
   * @param mixed $value Data to be cached
   * @param integer $duration How long to cache the data, in seconds
   * @return boolean True if the data was succesfully cached, false on failure
   * @see http://php.net/manual/en/memcached.set.php
   * @access public
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function write($key, &$value, $duration) {
    if ($duration > 30 * DAY && $duration < time()) {
            $duration = 0;
    }
    return $this->__Memcached->set($key, $value, $duration);
  }
  
  /**
   * Read a key from the cache
   *
   * @param string $key Identifier for the data
   * @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
   * @access public
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function read($key) {
    return $this->__Memcached->get($key);
  }
  
  /**
   * Read one or multiple keys from the cache ansync.
   * 
   * @param array $keys Array of identifiers for the data
   * @param callback $callback Callback that gets called when the data is fetched.
   * @param bool $withCas If true CAS tokens will be present in the return. OPTIONAL
   * @return bool Returns TRUE on success or FALSE on failure.
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function readAsync(&$keys, &$callback, $withCas = false){
    return $this->__Memcached->getDelayed($keys, $withCas, $callback);
  }
  
  /**
   * Read multiple keys from the cache
   * 
   * @param array $keys Array of identifiers for the data
   * @return mixed Returns the array of found items or FALSE on failure.
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function readMulti(&$keys){
    return $this->__Memcached->getMulti($keys, null, Memcached::GET_PRESERVE_ORDER);
  }
  
  /**
   * Increments the value of an integer cached key
   *
   * @param string $key Identifier for the data
   * @param integer $offset How much to increment
   * @param integer $duration How long to cache the data, in seconds
   * @return New incremented value, false otherwise
   * @access public
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function increment($key, $offset = 1) {
    return $this->__Memcached->increment($key, $offset);
  }
  
  /**
   * Decrements the value of an integer cached key
   *
   * @param string $key Identifier for the data
   * @param integer $offset How much to substract
   * @param integer $duration How long to cache the data, in seconds
   * @return New decremented value, false otherwise
   * @access public
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function decrement($key, $offset = 1) {
    return $this->__Memcached->decrement($key, $offset);
  }
  
  /**
   * Delete a key from the cache
   *
   * @param string $key Identifier for the data
   * @return boolean True if the value was succesfully deleted, false if it didn't exist or couldn't be removed
   * @access public
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function delete($key, $time) {
    return $this->__Memcached->delete($key, $time);
  }
  
  /**
   * Delete all keys from the cache
   *
   * @return boolean True if the cache was succesfully cleared, false otherwise
   * @access public
   * @since 0.1
   * @author Ezra Pool <[email protected]>
   */
  function clear($delay) {
    return $this->__Memcached->flush($delay);
  }
}
?>