<?php
    /* 实现session利用文件形式或者数据库等其它形式进行存储操作
     * author:Libin
     * Data:2014-06-24
     * 抽象顶层
    */
    abstract class session {
        /* open::设置存储路径 */
        abstract public function open();
        /* close::关闭存储模式句柄 */
        abstract public function close();
        /* read::根据key查询对应的value,典型的键值对 */
        abstract public function read($key);
        /* write::写session */
        abstract public function write($key,$value);
        /* destory::销毁某key的session */
        abstract public function destory($key);
        /* gc::回收机制，清除过期指定时间（分钟）session数据 */
        abstract public function gc($min = 0);
        /* start::开启session方法重写 */
        abstract public function start();
    }
?>

<?php
    /* 实现session利用文件形式或者数据库等其它形式进行存储操作
     * author:Libin
     * Data:2014-06-24
     * 文本(txt)实现方法
    */
    class session_txt extends session {
        
        /* 变量存储 */
        private $save_path   = '';//session保存路径
        private $file_path   = '';//session文件路径
        private $save_name   = '';//session命名
        private $save_hand   = null;//资源句柄
        private $save_prefix = 'mysession_';//session前缀
        
        /* open::设置存储路径 */
        final public function open(){
            $this->save_path = 'D:\session';
            if(!is_dir($this->save_path)){
                if(!mkdir($this->save_path)){
                    return false;
                };
            }
            $this->gc();//启用回收机制
            return true;
        }
        /* close::关闭存储模式句柄 */
        final public function close(){
            return true;
        }
        /* read::根据key查询对应的value,典型的键值对 */
        final public function read($key){
            $this->set(__function__,$key);
            $data = @fread($this->save_hand,filesize($this->file_path));
            if(empty($data) || $data == ''){
                return '';
            }return $data;
        }
        /* write::写session */
        final public function write($key,$value){
            $this->set(__function__,$key);
            return @fwrite($this->save_hand,$value);
        }
        /* destory::销毁某key的session */
        final public function destory($key){
            $this->set(__function__,$key);
            return @unlink($this->file_path);
        }
        /* gc::回收机制，清除过期指定时间（分钟）session数据 */
        final public function gc($min = 10){
            $hand = @opendir($this->save_path);//打开文件夹
            while($file = @readdir($hand)){//遍历文件夹
                if(is_file($this->save_path.'/'.$file)){//如果为文件，排除.||..
                    $fileatime = fileatime($this->save_path.'/'.$file);//获取文件最后修改时间
                    if(((time() - $fileatime) / 60) > $min){//如果时间相差大于$min分钟
                        unlink($this->save_path.'/'.$file);//执行文件清理功能
                    }
                }
            }
            return true;
        }
        
        #################################################################################
        
        /* MAGIC __SET */
        final public function __set($key,$value){
            $this->$key = $value;
            return true;
        }
        
        /* 获取存储句柄 */
        final private function set($mode = 'read',$key){
            $this->file_path = $this->save_path.'/'.$this->save_prefix.$key;//设置文件路径
            if($mode != 'read' && $mode != 'write'){return false;};
            $mode = $mode == 'write' ? 'w' : 'r';//读或写
            $this->save_hand = @fopen($this->file_path,$mode);
        }
        
        /* start::开启session方法重写 */
        final public function start(){
            @session_set_save_handler(array($this,'open'),array($this,'close'),array($this,'read'),array($this,'write'),array($this,'destory'),array($this,'gc'));
            ob_start();
            session_start();
            ob_end_flush();
        }
    }
?>