php 更改 SESSION 变量值
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Change SESSION variable value
提问by William Orazi
I've been attempting to figure this out for a little while now, and it's driving me nuts. Basically I have a form for US and Canadian users. There's a link at the bottom of the form for Canadian users, which directs users to can-sesssion.php, which contains:
一段时间以来，我一直试图弄清楚这一点，这让我发疯了。基本上我有一个供美国和加拿大用户使用的表格。表格底部有一个供加拿大用户使用的链接，可将用户引导至 can-session.php，其中包含：
<?php
if (isset($_SESSION['can'])) {
session_start();
session_destroy();
session_unset();
session_start();
$_SESSION['can'] = 2;
}
else {
session_start();
$_SESSION['can'] = 1;
}
header('Location: '. $_SERVER['HTTP_REFERER'] . '');
?>
Basically, if they click on the link, it sets $_SESSION['can'] = 1. Now There's another option, and if they click that link, it takes them back to this page, and the session should be destroyed and a new value is set (well, that's what it's supposed to do). Problem is, I've printed out $_SESSION['can'], and it's still retaining that old value after going to that page. Is there a better way to do this, or is there something wrong w/ my code? Thanks for the help.
基本上，如果他们点击链接，它会设置 $_SESSION['can'] = 1。现在还有另一个选项，如果他们点击那个链接，它会将他们带回这个页面，会话应该被销毁，一个新的值已设置（嗯，这就是它应该做的）。问题是，我已经打印出 $_SESSION['can']，并且在转到该页面后它仍然保留该旧值。有没有更好的方法来做到这一点，或者我的代码有什么问题？谢谢您的帮助。
回答by Dan Grossman
This is what you wrote:
这是你写的：
if (isset($_SESSION['can'])) {
session_start();
session_startis the function which reads the session file associated with the user's PHPSESSIDcookie and populates $_SESSION, so you're trying to read from the array before it has any values.
session_start是读取与用户的PHPSESSIDcookie关联的会话文件并填充的函数$_SESSION，因此您试图在数组具有任何值之前从数组中读取。
You need to call session_startbeforeyou check if $_SESSION['can']has a value.
您需要session_start在检查是否$_SESSION['can']有值之前调用。
You also do not need to destroy and create a new session just to change a value.
您也不需要为了更改值而销毁和创建新会话。
<?php
session_start();
if (isset($_SESSION['can'])) {
$_SESSION['can'] = 2;
} else {
$_SESSION['can'] = 1;
}
header('Location: '. $_SERVER['HTTP_REFERER'] . '');
?>
回答by Naftali aka Neal
Try this: (using only onesession_start())
试试这个：（只使用一个session_start()）
<?php
session_start();
if (isset($_SESSION['can'])) {
$_SESSION['can'] = 2;
}
else {
$_SESSION['can'] = 1;
}
header('Location: '. $_SERVER['HTTP_REFERER'] . '');
?>
回答by Just Another Coder
You may want to include
你可能想包括
if (session_status() == PHP_SESSION_NONE) {
session_start();
}
instead of just plain
而不是简单的
session_start();
