PHP全局变量未导入会话处理程序

Question

我正在使用ADOdb.由于某种原因,实际上$db没有在'write'函数中导入.

该函数用于导入$db实际值.相反,它将空值分配给$db:

<?php
// load ADODB class
include(DIR_WS_CLASSES . "adodb5/adodb.inc.php");

$db = NewADOConnection(DB_TYPE);
$db->Connect(DB_SERVER, DB_SERVER_USERNAME, DB_SERVER_PASSWORD, DB_DATABASE);


class SessionManager {
    var $life_time;

    function SessionManager(){
        global $db;
        // Read the maxlifetime setting from PHP
        $this->life_time = get_cfg_var("session.gc_maxlifetime");

        // Register this object as the session handler
        session_set_save_handler(array(&$this, "open"), 
                                array(&$this, "close"), 
                                array(&$this, "read"), 
                                array(&$this, "write"), 
                                array(&$this, "destroy"), 
                                array(&$this, "gc"));
    }

    function open($save_path, $session_name){
        global $sess_save_path;
        global $db;

        $sess_save_path = $save_path;

        return true;
    }

    function close(){
        global $db;
        return true;
    }

    function read($id){
        global $db;
        // Set empty result
        $data = '';

        // Fetch session data from the selected database
        $time = time();
        $newid = $db->qstr($id, get_magic_quotes_gpc());

        $sql = "SELECT session_data 
                FROM sessions 
                WHERE session_id = $newid 
                AND expires > $time";

        $rs = $db->Execute($sql) or die($db->ErrorMsg());
        $a = $rs->RecordCount();

        if($a > 0){
            $data = $rs->fields['session_data'];
        }

        return $data;
    }

    function write($id, $data){
        global $db;
        // Build query                
        $time = time() + $this->life_time;
        $newid = $db->qstr($id, get_magic_quotes_gpc());
        $newdata = $db->qstr($data, get_magic_quotes_gpc());
        $sql = "REPLACE sessions
                (session_id, session_data, expires) 
                VALUES($newid, $newdata, $time)";

        $rs = $db->Execute($sql) or die($db->ErrorMsg());

        return TRUE;
    }

    function destroy($id){
        global $db;
        // Build query
        $newid = $db->qstr($id, get_magic_quotes_gpc());
        $sql = "DELETE FROM sessions 
                WHERE session_id = $newid";

        $db->Execute($sql) or die($db->ErrorMsg());

        return TRUE;
    }

    function gc(){
    // Garbage Collection
        global $db;
        // Build DELETE query.  Delete all records that passed expiration time
        $sql = "DELETE FROM sessions 
                WHERE expires < UNIX_TIMESTAMP()";

        $db->Execute($sql) or die($db->ErrorMsg());

        // Always return TRUE
        return true;
    }
}


// initialize session
$sess = new SessionManager();
session_start();
?>

为什么实际$db未在'write'函数中导入？

我该如何解决这个问题？

Answer 1

为那些不遵守评论的人编辑;)

"从PHP 5.0.5开始,写入和关闭处理程序在对象销毁后被调用,因此不能使用对象或抛出异常.但是对象析构函数可以使用会话.可以从析构函数中调用session_write_close()来解决这个问题.蛋问题"

所以我的想法就是拥有这样的析构函数:

function __destruct() {
    session_write_close();
}

这样就可以在write和close处理程序中使用这些对象.

然后,为了安全起见,要在write&close中重新实例化$ db,因为可以在SessionHandler之前调用全局$ db析构函数.