Memcached分布存储代码示例

这一部分是一个实例，我现在正在用的一个扩展的 Memcache 类，叫 Memcachez，用于多 server 的目的而写，里面还添了点出于自己喜好而使用的风格。使用的方法是填装一个数组形式的 server 群，之后就可以基本照常 add/set/get 了。

<?PHP   
$cfg["cache"] = array(   
    "192.168.0.8:11211",   
    "192.168.0.9:11211"  
);   
  
$oCache = new Memcachez($cfg["cache"]);   
?>  

类代码如下：

<?PHP   
/*  
 * MemCacheZ  
 *  
 * 多台服务器时自动根据 key 的 crc32 值来选择相应服务器  
 *  
 * Zheng Kai 2007-04-29 18:28:10  
 */  
  
/*  
 
  method:  
 
    setCompress (boolean) 是否使用 gzip 压缩（add/set/replace）  
    setExpire   (int)     设置过期时间  
 
    add  
    set  
    get  
    replace  
    increment  
    decrement  
 
    以上这些照常使用  
 
    不过注意 add/set/replace 这三个方法的原第三个参数（是否 zlib 压缩）已经省略，  
    由最后一次 setCompress 来决定；最后一个参数 iExpire 如果为空则沿用 setExpire  
    的设置，如果都不填，则缺省的默认时间为一小时  
 
 */  
  
class Memcachez {   
  
    protected $aLink = array();   
  
    protected $aServerList = array();   
    protected $iServerNumber = 3;   
  
    protected $iCompress = 0;   
    protected $iCompressNow = 0;   
  
    protected $iExpire = 3600;   
    protected $iExpireNow = 3600;   
  
    protected $iServerNow = -1;   
  
    function __construct($aServerList) {   
        $this->aServerList = array_values($aServerList);   
        $this->iServerNumber = count($aServerList);   
    }   
  
  
    public function setCompress($sSwitch = "") {   
        if (empty($sSwitch)||(strtolower($sSwitch) == "false")) {   
            $this->iCompress = 0;   
        } else {   
            $this->iCompress = MEMCACHE_COMPRESSED;   
        }   
    }   
  
    public function setExpire($iExpire) {   
        $iExpire = intval($iExpire);   
        if ($iExpire > 1) {   
            $this->iExpire = $iExpire;   
        }   
    }   
  
    // 选择 memcached server   
    protected function _selectServer($sKey, $bServerID = FALSE) {   
  
        if ($bServerID) {   
            $iServerID = intval($sKey);   
        } else {   
            $iServerID = sprintf("%u", crc32($sKey)) % $this->iServerNumber;   
        }   
  
        if (($this->iServerNow != $iServerID)&&(!array_key_exists($iServerID, $this->aLink))) {   
            $this->aLink[$iServerID] = new Memcache();   
            list($sHost, $iPort) = explode(":", $this->aServerList[$iServerID]);   
            $this->aLink[$iServerID]->connect($sHost, $iPort);   
        }   
        $this->iServerNow = $iServerID;   
  
    }   
  
    // 选择过期时间   
    protected function _selectExpire($iExpire) {   
        $this->iExpireNow = ($iExpire <= 0) ? $this->iExpire : $iExpire;   
    }   
    protected function _selectCompress($iCompress) {   
        $this->iExpireNow = ($iCompress <= 0) ? $this->iCompressNow : $iCompress;   
    }   
  
    // add   
    public function add($sKey, $sValue, $iExpire = 0, $iCompress = 0) {   
        $this->_selectServer($sKey);   
        $this->_selectExpire($iExpire);   
        $this->_selectCompress($iCompress);   
        return $this->aLink[$this->iServerNow]->add($sKey, $sValue, $this->iCompressNow, $this->iExpireNow);   
    }   
  
    // set   
    public function set($sKey, $sValue, $iExpire = 0, $iCompress = 0) {   
        $this->_selectServer($sKey);   
        $this->_selectExpire($iExpire);   
        $this->_selectCompress($iCompress);   
        return $this->aLink[$this->iServerNow]->set($sKey, $sValue, $this->iCompressNow, $this->iExpireNow);   
    }   
  
    // replace   
    public function replace($sKey, $sValue, $iExpire = 0, $iCompress = 0) {   
        $this->_selectServer($sKey);   
        $this->_selectExpire($iExpire);   
        $this->_selectCompress($iCompress);   
        return $this->aLink[$this->iServerNow]->replace($sKey, $sValue, $this->iCompressNow, $this->iExpireNow);   
    }   
  
    // get   
    public function get($sKey) {   
        $this->_selectServer($sKey);   
         return $this->aLink[$this->iServerNow]->get($sKey);   
    }   
  
    // delete   
    public function delete($sKey, $iTimeout = 0) {   
        $this->_selectServer($sKey);   
        return $this->aLink[$this->iServerNow]->delete($sKey, $iTimeout);   
    }   
  
    // increment   
    public function increment($sKey, $iValue) {   
        $this->_selectServer($sKey);   
        return $this->aLink[$this->iServerNow]->increment($sKey, $iValue);   
    }   
  
    // decrement   
    public function decrement($sKey, $iValue) {   
        $this->_selectServer($sKey);   
        return $this->aLink[$this->iServerNow]->decrement($sKey, $iValue);   
    }   
  
    // getStats   
    public function getStats() {   
        $aStats = array();   
        foreach ($this->aServerList as $iKey => $sValue) {   
            $this->_selectServer($iKey, TRUE);   
            $aStats[$sValue] = $this->aLink[$iKey]->getStats();   
        }   
        return $aStats;   
    }   
  
    // flush   
    public function flush() {   
        foreach ($this->aServerList as $iKey => $sValue) {   
            $this->_selectServer($iKey, TRUE);   
            $this->aLink[$iKey]->flush();   
        }   
    }   
}   
?>