<?php
/*============================文件說(shuō)明========================================
@filename:     session.class.php
@description:  數(shù)據(jù)庫(kù)保存在線(xiàn)用戶(hù)session，實(shí)現(xiàn)在線(xiàn)用戶(hù)功能！
@notice:       session過(guò)期時(shí)間一個(gè)小時(shí)，因?yàn)槲覀兊恼军c(diǎn)是使用cookie（有效時(shí)間是1小時(shí)）登錄。                
　　　　　　　 因此我們只記錄用戶(hù)登錄的時(shí)間，而不是刷新一次更新一次                
　　　　　　　 刪除數(shù)據(jù)庫(kù)中session記錄的動(dòng)作發(fā)生在用戶(hù)超時(shí)后執(zhí)行這個(gè)文件或正常退出（session_destory） 
@database:     database:sessions  field:sessionid(char32),uid(int10),last_visit(int10)
=============================================================================
*/
 class session {
     private $db;
     private $lasttime=3600;//超時(shí)時(shí)間：一個(gè)小時(shí)
      function session(&$db) {
         $this->db = &$db;
         session_module_name('user'); //session文件保存方式，這個(gè)是必須的！除非在Php.ini文件中設(shè)置了
         session_set_save_handler(
             array(&$this, 'open'), //在運(yùn)行session_start()時(shí)執(zhí)行
              array(&$this, 'close'), //在腳本執(zhí)行完成或調(diào)用session_write_close() 或 session_destroy()時(shí)被執(zhí)行,即在所有session操作完后被執(zhí)行
             array(&$this, 'read'), //在運(yùn)行session_start()時(shí)執(zhí)行,因?yàn)樵趕ession_start時(shí),會(huì)去read當(dāng)前session數(shù)據(jù)
             array(&$this, 'write'), //此方法在腳本結(jié)束和使用session_write_close()強(qiáng)制提交SESSION數(shù)據(jù)時(shí)執(zhí)行
              array(&$this, 'destroy'), //在運(yùn)行session_destroy()時(shí)執(zhí)行
              array(&$this, 'gc') //執(zhí)行概率由session.gc_probability 和 session.gc_divisor的值決定,時(shí)機(jī)是在open,read之后,session_start會(huì)相繼執(zhí)行open,read和gc
         );
         session_start(); //這也是必須的，打開(kāi)session，必須在session_set_save_handler后面執(zhí)行
     }
        function unserializes($data_value) {
         $vars = preg_split(
             '/([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\|/',
             $data_value, -1, PREG_SPLIT_NO_EMPTY |
             PREG_SPLIT_DELIM_CAPTURE
         );
         for ($i = 0; isset($vars[$i]); $i++) {
             $result[$vars[$i++]] = unserialize($vars[$i]);
         }
         return $result;
     } 
     function open($path, $name) {
         return true;
     }
     function close() {
         $this->gc($this->lasttime);
         return true;
     }
    function read($SessionKey){
         $sql = "SELECT uid FROM sessions WHERE session_id = '".$SessionKey."' limit 1";
         $query =$this->db->query($sql);
         if($row=$this->db->fetch_array($query)){
           return $row['uid'];
         }else{
             return "";
         }
              }
     function write($SessionKey,$VArray) {
         require_once(MRoot.DIR_WS_CLASSES .'db_mysql_class.php');
        $db1=new DbCom();
       // make a connection to the database... now
        $db1->connect(DB_SERVER, DB_SERVER_USERNAME, DB_SERVER_PASSWORD, DB_DATABASE);
        $db1->query("set names utf8");
        $this->db=$db1;
        $SessionArray = addslashes($VArray);
         $data=$this->unserializes($VArray);  
                          $sql0 = "SELECT uid FROM sessions WHERE session_id = '".$SessionKey."' limit 1";
         $query0 =$this->db->query($sql0);
         if($this->db->num_rows($query0)<=0){
             if (isset($data['webid']) && !empty($data['webid'])) {
                $this->db->query("insert into `sessions` set `session_id` = '$SessionKey',uid='".$data['webid']."',last_visit='".time()."'");
             }   
                    return true;
         }else{
             /*$sql = "update `sessions` set ";
             if(isset($data['webid'])){
             $sql .= "uid = '".$data['webid']."', " ;
             }
             $sql.="`last_visit` = null "
                   . "where `session_id` = '$SessionKey'";
                               $this->db->query($sql); */
             return true;
         }   
     }
   function destroy($SessionKey) {
      $this->db->query("delete from `sessions` where `session_id` = '$SessionKey'");
      return true;
    }
    function gc($lifetime) {
        $this->db->query("delete from `sessions` where unix_timestamp(now()) -`last_visit` > '".$this->lasttime."'");
        return true;
    }
     }
 ?>