PHP implements the definition and use of redis cache class

<?php

class redisCache {

  /**

  * $host : redis服务器ip

  * $port : redis服务器端口

  * $lifetime : 缓存文件有效期,单位为秒

  * $cacheid : 缓存文件路径,包含文件名

  */

  private $host;

  private $port;

  private $lifetime;

  private $cacheid;

  private $data;

  public $redis;

  /**

  * 析构函数,检查缓存目录是否有效,默认赋值

  */

  function __construct($lifetime=1800) {

    //配置

    $this->host = "127.0.0.1";

    $this->port = "6379";

    $redis = new Redis();

    $redis->pconnect($this->host,$this->port);

    $this->redis=$redis;

    $this->cacheid = $this->getcacheid();

    $this->lifetime = $lifetime;

    $this->data=$redis->hMGet($this->cacheid, array('content','creattime'));

    //print_r($this->redis);

    //print_r($this->data);

  }

  /**

  * 检查缓存是否有效

  */

  private function isvalid(){

    $data=$this->data;

    if (!$data['content']) return false;

    if (time() - $data['creattime'] > $this->lifetime) return false;

    return true;

  }

  /**

  * 写入缓存

  * $mode == 0 , 以浏览器缓存的方式取得页面内容

  */

  public function write($mode=0,$content='') {

    switch ($mode) {

      case 0:

        $content = ob_get_contents();

        break;

      default:

        break;

    }

    ob_end_flush();

    try {

      $this->redis->hMset($this->cacheid, array('content'=>$content,'creattime'=>time()));

      $this->redis->expireAt($this->cacheid, time() + $this->lifetime);

    }

    catch (Exception $e) {

      $this->error('写入缓存失败!');

    }

  }

  /**

  * 加载缓存

  * exit() 载入缓存后终止原页面程序的执行,缓存无效则运行原页面程序生成缓存

  * ob_start() 开启浏览器缓存用于在页面结尾处取得页面内容

  */

  public function load() {

    if ($this->isvalid()) {

      echo $this->data['content'];

      exit();

    }

    else {

      ob_start();

    }

  }

  /**

  * 清除缓存

  */

  public function clean() {

    try {

      $this->redis->hDel($this->cacheid, array('content','creattime'));

    }

    catch (Exception $e) {

      $this->error('清除缓存失败!');

    }

  }

  /**

  * 取得缓存文件路径

  */

  private function getcacheid() {

    return $this->dir.md5($this->geturl()).$this->ext;

  }

  /**

  * 取得当前页面完整url

  */

  private function geturl() {

    $url = '';

    if (isset($_SERVER['REQUEST_URI'])) {

      $url = $_SERVER['REQUEST_URI'];

    }

    else {

      $url = $_SERVER['Php_SELF'];

      $url .= empty($_SERVER['QUERY_STRING'])?'':'?'.$_SERVER['QUERY_STRING'];

    }

    return $url;

  }

  /**

  * 输出错误信息

  */

  private function error($str) {

    echo &#39;<p style="color:red;">&#39;.$str.&#39;</p>&#39;;

  }

}

//用法：

// require_once('redisCache.php');

// $cache = new redisCache(10); //设置缓存生存期

// if ($_GET['clearCache']) $cache->clean();

// else $cache->load(); //装载缓存,缓存有效则不执行以下页面代码

// //页面代码开始

// //页面代码结束

// $cache->write(); //首次运行或缓存过期,生成缓存

?>