超簡單的php緩存類

php緩存    

<?php
class Cache 
{
    private $dir = "data/cache/";//定義緩存目錄   
    private $key='c_a_sss'; // 文件名 md5加密 密鑰

    function set_dir($dirpath)
    {
        $this->dir=$dirpath;
        $this->make_dir($this->dir);
    }
    function read($key,$minutes=1)
    {
        $filename=$this->get_filename($key);
        if($datas = @file_get_contents($filename))
        {
          $datas = unserialize($datas);
          if(time() - $datas['time'] < $minutes*60)
          {
            return $datas['data'];
          }
        }
        return false;
    }

    function write($key,$data)
    {       
        $filename=$this->get_filename($key);
        if($handle = fopen($filename,'w+'))
        {
            $datas = array('data'=>$data,'time'=>time());
            flock($handle,LOCK_EX);
            $rs = fputs($handle,serialize($datas));
            flock($handle,LOCK_UN);
            fclose($handle);
            if($rs!==false){return true;  }
        }
        return false;
    }
    function clear_all()
    {
        $dir=$this->dir;
        $this->del_file($dir);   
    }

    private function get_filename($key)
    {
        return $this->dir.$key.'_'.md5($key.$this->key);
    }
    private function make_dir($path)
    {
        if (! file_exists ( $path ))
        {
            if (! mkdir ( $path, 0777,true)) die ( '無法創建緩存文件夾' . $path );
        }
    }
    private function del_file($dir)
    { 
        if (is_dir($dir)) 
        { 
            $dh=opendir($dir);//打開目錄 //列出目錄中的所有文件并去掉 . 和 .. 
            while (false !== ( $file = readdir ($dh))) { 
                if($file!="." && $file!="..") {
                    $fullpath=$dir."/".$file; 
                    if(!is_dir($fullpath)) { 
                        unlink($fullpath);
                    } else { 
                        $this->del_file($fullpath); 
                    } 
                }
            }
            closedir($dh); 
        } 
    } 
}

$cache = new cache();
        $cache->set_dir('data/cache_dir/');
        $data=$cache->read('sys',1);
        if(empty($data))
        {
            $data=array('aa'=>1111,'bb'=>2222,'date'=>date('Y-m-d H:i:s'));
            $cache->write('sys',$data);  
        }
        print_r($data);