PHP session 困惑

标签 php session class

好吧，我很困惑。我有一个存储在 session 中的对象。我可以向这个对象添加项目。到目前为止很简单。我这样初始化对象:

$template = new Template($mysqli);
$_SESSION['template'] = serialize($template);

现在应该创建一个全新的品牌对象并将其分配给 session 。然后我有一些代码通过 AJAX 请求添加项目。该代码如下:

$template = unserialize($_SESSION['template']);
$prodid = $_GET['product_id'];
$template->addItem($prodid);
echo var_dump($template->getItems());
$_SESSION['template'] = serialize($template);

同样，应该很简单。现在的问题是，第一段代码没有重置 $_SESSION['template'] 而它应该重置，所以我得到了到目前为止添加的所有项目，重新加载页面没有修复它。

我找到了导致问题的文件，但我不知道我能做些什么。它是一个包含项，网站的不同部分都需要它才能正常运行。我正在向网站添加功能，如果我删除功能，我认为所有者不会满意。这是文件:

<?php

include_once( 'DBE.class.php' ) ;

################################################
# Function: Sessions_open
# Parameters: $path (string), $name (string)
# Returns: bool
# Description: This is an over-ride function call
#       that we need to create so that the php internal
#       session manager doesn't store our session in the
#       file system, since we are storing it in the
#       db. Storing a session in a file system on the
#       server inhibits scalability for two reasons:
#       1: A large number of users may be hitting the site
#           and clog the space on the hard-drive of the server
#           due to the sheer amount of session files stored
#       2: The website may be behind a load-balancer and
#           therefore the server handling the page request
#           may not have the session stored on its file system
################################################
function Sessions_open ( $path, $name ) {
    return TRUE ;
}


################################################
# Function: Sessions_close
# Parameters: N/A
# Returns: bool
# Description: This is an over-ride function call
#       that we need to create so that the php internal
#       session manager doesn't store our session in the
#       file system, since we are storing it in the
#       db. Storing a session in a file system on the
#       server inhibits scalability for two reasons:
#       1: A large number of users may be hitting the site
#           and clog the space on the hard-drive of the server
#           due to the sheer amount of session files stored
#       2: The website may be behind a load-balancer and
#           therefore the server handling the page request
#           may not have the session stored on its file system
################################################
function Sessions_close () {
    return TRUE ;
}


################################################
# Function: Sessions_read
# Parameters: $SessionID (string)
# Returns: (string) or (false) on error
# Description: This function is used at startup to read
#           the contents of the session. 
#           If no sess data, the empty string ("") is returned.
#           Otherwise, the serialized sess data is returned.
#           On error, false is returned.
################################################
function Sessions_read ( $SessionID ) {

    include_once( 'DBE.class.php' ) ;
    $dbe = new DBE() ;

    //default return value to false
    $returnVal = FALSE ;

    $query = "SELECT DataValue
                        FROM Sessions 
                        WHERE SessionID = '$SessionID' " ;

    $result = $dbe->Select( $query ) ;

    if( count( $result ) == 1 ) {
        $returnVal = $result[0]['DataValue'] ;

        //update the session so that we don't time-out after creating
        $query = "UPDATE Sessions
                            SET LastUpdated = NOW()
                            WHERE SessionID = '$SessionID'" ;
        $dbe->Update( $query ) ;

    } else {
        //Insert here to simplify the write function
        $query = "INSERT INTO Sessions (SessionID, DataValue) VALUES ( '$SessionID', '' )" ;

        $dbe->Insert( $query ) ;            //pass the insert stmt

        //set returnVal to '' being that we didn't find the SessionID
        $returnVal = '' ;
    }

    return( $returnVal ) ;
}

################################################
# Function: Sessions_write
# Parameters: $SessionID (string), $Data
# Returns: bool
# Description: This function is used at startup to read
#           the contents of the session. 
#           If no sess data, the empty string ("") is returned.
#           Otherwise, the serialized sess data is returned.
#           On error, false is returned.
################################################
function Sessions_write( $SessionID, $Data ) {

    include_once( 'DBE.class.php' ) ;
    $dbe = new DBE() ;

    //default to true
    $returnVal = TRUE ;

    //update the session
    $query = "UPDATE Sessions 
                            SET DataValue = '$Data'
                        WHERE SessionID = '$SessionID'" ;

    $result = $dbe->Update( $query ) ; //pass the update stmt to the dbEngine..

    //test for success
    if( $result == -1 )
        $returnVal = FALSE ;

    //return the return value
    return( $returnVal ) ;
}


################################################
# Function: Sessions_delete
# Parameters: $SessionID (string)
# Returns: bool
# Description: This function is used to delete the session
################################################
function Sessions_destroy( $SessionID ) {

    include_once( 'DBE.class.php' ) ;
    $dbe = new DBE() ;

    $query = "DELETE FROM Sessions WHERE SessionID = '$SessionID' " ;

    $dbe->Delete( $query ) ;

    return( TRUE ) ;
}

################################################
# Function: Sessions_delete
# Parameters: $SessionID (string)
# Returns: bool
# Description: This function is used to delete the session
################################################
function Sessions_gc( $aMaxLifetime ) {

    include_once( 'DBE.class.php' ) ;
    $dbe = new DBE() ;

    $query = "DELETE FROM Sessions WHERE (UNIX_TIMESTAMP(NOW()) - UNIX_TIMESTAMP( LastUpdated )) > $aMaxLifetime " ;

    $dbe->Delete( $query ) ;

    return( TRUE ) ;
}

    session_set_save_handler( "Sessions_open", "Sessions_close",
                                 "Sessions_read", "Sessions_write",
                                 "Sessions_destroy", "Sessions_gc" ) ;

?>

我认为这正在改变 session 的基本功能，但我不太确定。这导致我在 session 中重置模板时遇到麻烦。任何人都有任何想法或知道我能做些什么来解决这个问题。我完全被难住了，所以非常感谢任何帮助。

最佳答案

我不确定这是否是问题所在，但这是我阅读您的代码时跳出的内容:

您的序列化对象依赖于 mysql 连接

$template = new Template($mysqli);

虽然您的对象(也许)可以毫无问题地序列化和反序列化，但 mysql 连接不能，因此您的未序列化 $template 会尝试对无效的连接/文件句柄进行操作。

您可以尝试将未序列化的对象重新附加到有效的数据库连接。

不知道您的模板类中有什么(以及它使用什么资源以及如何使用)，很难猜出哪里出了问题，但我希望这是一个足够好的线索，让我们知道从哪里开始寻找。

为了让您更好地理解我在说什么，请考虑以下内容:

模板.php

<?php

class Template {
 function __construct($c) {
   $this->conn = $c;
   $this->foo = "bar";
 }
 function get_data() {
  $result = mysql_query("select 1234 as test", $this->conn);
  $data = mysql_fetch_array($result);
  return $data;
 }
 
 function attach_db($c) {
   $this->conn = $c;
 }
}

?>

首先.php

<?php
session_start();
require('template.php');

$conn = mysql_connect('localhost', 'root', '');
$template = new Template($conn);
?>
<pre>

Your $template var, freshly created:
<?php var_dump($template); ?>

Accessing the resources:
<?php var_dump($template->get_data()); ?>

<?php
$_SESSION['template'] = serialize($template);
?>

</pre>

其他.php

<?php
session_start();
require('template.php');

$template = unserialize($_SESSION['template']);
?>
<pre>

Unserialized $template:
<?php var_dump($template); ?>
(notice that $template->foo === "bar" so your session un/serialization is working correctly)

Accessing the (now invalid) mysql resources:
<?php var_dump($template->get_data()); ?>

</pre>

调用 first.php 应该给你这个:

Your $template var, freshly created:
object(Template)#1 (2) {
["conn"]=>
resource(3) of type (mysql link)
["foo"]=>
string(3) "bar"
}

Accessing the resources:
array(2) {
[0]=>
string(4) "1234"
["test"]=>
string(4) "1234"
}

调用 others.php 应该导致:

Unserialized $template:
object(Template)#1 (2) {
["conn"]=>
int(0)
["foo"]=>
string(3) "bar"
}
(notice that $template->foo === "bar" so your session un/serialization is working correctly)

Accessing the (now invalid) mysql resources:

Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource in template.php on line 9

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in template.php on line 10

bool(false)

要解决这个问题，您可以重新创建无法反序列化的资源。
像这样:

解决方案.php

<?php
session_start();
require('template.php');

$template = unserialize($_SESSION['template']);
?>
<pre>

Unserialized $template:
<?php var_dump($template); ?>

Attaching a valid db connection:
<?php
$conn = mysql_connect('localhost', 'root', '');
$template->attach_db($conn);
var_dump($template);
?>

Accessing the resources:
<?php var_dump($template->get_data()); ?>

</pre>

现在，在调用 first.php 之后调用 solution.php 应该会得到:

Unserialized $template:
object(Template)#1 (2) {
["conn"]=>
int(0)
["foo"]=>
string(3) "bar"
}

Attaching a valid db connection:
object(Template)#1 (2) {
["conn"]=>
resource(3) of type (mysql link)
["foo"]=>
string(3) "bar"
}

Accessing the resources:
array(2) {
[0]=>
string(4) "1234"
["test"]=>
string(4) "1234"
}

正如我所说，在不知道您的模板类做什么的情况下，无法确定发生了什么。这只是一种可能性；)

祝你好运!

关于PHP session 困惑，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/1038830/

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