php+Redis缓存

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<?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 '<div style="color:red;">' . $str . '</div>';
    }
}


//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


?>