php 未定义的变量：_SESSION 当通过 JavaScript 触发器通过 post 发送变量时
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Undefined variable: _SESSION when sending variables via post through JavaScript trigger
提问by keybored
In my index.php file I call session_start()and set a couple of session variables. In a second PHP file I would like to access these session variables.
在我的 index.php 文件中，我调用session_start()并设置了几个会话变量。在第二个 PHP 文件中，我想访问这些会话变量。
Thing is, this PHP file is purely a backend script and is POSTed to when a JavaScript function is triggered. When the POST call attempts to cause the script in the second PHP file to be executed the error log is reporting that:
事实是，这个 PHP 文件纯粹是一个后端脚本，并在 JavaScript 函数被触发时被 POST 到。当 POST 调用试图导致执行第二个 PHP 文件中的脚本时，错误日志报告：
_SESSIONis an undefined variable.
_SESSION是一个未定义的变量。
I've tried calling start_session()and session_regenerate_id()at the top of the second PHP file but the issue has persisted.
我试过在第二个 PHP 文件的顶部调用start_session()和session_regenerate_id()但问题仍然存在。
I'm assuming what is going on is that because it's in a POST this PHP file is in its own session as I am still able to do this $_COOKIE[ini_get('session.name')].
我假设正在发生的事情是因为它在 POST 中，这个 PHP 文件在它自己的会话中，因为我仍然能够做到这一点$_COOKIE[ini_get('session.name')]。
The information that I am trying to pass to the second PHP file isn't anything that needs to be secured but it would be nice to know in the future how to do this: call a PHP file via a POST and still have my session variables.
我试图传递给第二个 PHP 文件的信息不是任何需要保护的信息，但很高兴知道将来如何执行此操作：通过 POST 调用 PHP 文件并仍然保留我的会话变量.
回答by deceze
There's nothing special whatsoever about POST requests and sessions.
You just need to call session_startat the top of everyfilerequest you want to use sessions in, that's it.
POST 请求和会话没有什么特别之处。
您只需要session_start在要使用会话的每个文件请求的顶部调用，就是这样。
Try again with that in mind, it ought to work.
记住这一点再试一次，它应该可以工作。
回答by Gorkem Yontem
session_start();
is the answer of most of topic like this. i have been struggling with this issue and i solve my problem with this code
是大多数主题的答案。我一直在努力解决这个问题，我用这段代码解决了我的问题
if (version_compare(PHP_VERSION, '5.4.0', '<')) {
if(session_id() == '') {session_start();}
} else {
if (session_status() == PHP_SESSION_NONE) {session_start();}
}
回答by robertparkerx
you must include
你必须包括
<?php session_start();?>
at the beginning of your document, this will start the SESSION ENGINE and enable you to set session variables (ie. $_SESSION['var1'], $_SESSION['var2'], etc)
在文档的开头，这将启动会话引擎并使您能够设置会话变量 (ie. $_SESSION['var1'], $_SESSION['var2'], etc)
If you're wanting to get values from a $_POST you could relate the two together by :
如果您想从 $_POST 获取值，您可以通过以下方式将两者联系起来：
$_SESSION['var1'] = $_POST['answer1']
回答by Ashahmali
I came faced with this problem, and after trying a lot of things, I just included session_start() on the second script and it worked.
我遇到了这个问题，在尝试了很多事情之后，我只是在第二个脚本中包含了 session_start() 并且它起作用了。
回答by Dung Dinh
Add the following code to the file browse.php:
将以下代码添加到文件 browse.php 中：
error_reporting( error_reporting() & ~E_NOTICE );
if( ! ini_get('date.timezone') )
{
date_default_timezone_set('GMT');
}
if (version_compare(PHP_VERSION, '5.4.0', '<')) {
if(session_id() == '') {session_start();}
} else {
if (session_status() == PHP_SESSION_NONE) {session_start();}
}
It will work fine.
它会正常工作。
回答by Farhad
I had this problem and tried different ways and finally found a solution :
我遇到了这个问题并尝试了不同的方法，最后找到了解决方案：
PHP is case sensitive, Use $_SESSION instead of $_session in all php files.certainly It works . Example :
PHP 区分大小写，在所有 php 文件中使用 $_SESSION 而不是 $_session。当然可以。例子 ：
<?php
session_save_path('tmp/'); (is not optional - it is mandatory)
session_start();
echo $_SESSION["s1"]."<br/>";
echo $_SESSION["s2"]."<br/>";
?>
回答by user28864
I also encountered the same problem recently. I could not access the contents of the $_SESSION variable.
我最近也遇到了同样的问题。我无法访问 $_SESSION 变量的内容。
1) This was as a result of trying to access the $_SESSION variable before the declaration of session_start();In my own case, I had already started a session in a header.php file. But I was accessing the $_SESSION variable before the include statement. Example;
1) 这是在声明之前尝试访问 $_SESSION 变量的结果session_start();在我自己的情况下，我已经在 header.php 文件中启动了一个会话。但是我在 include 语句之前访问了 $_SESSION 变量。例子;
<?php
$username = $_SESSION['username'];
//do some logical operation!!!
?>
<?php include("header.php");?>
instead of doing something like this
而不是做这样的事情
<?php include("header.php");?>
<?php
$username = $_SESSION['username'];
//do some logical operation!!!
?>
2) Another thing that may cause this problem, maybe a failure to start a session at the top of all the files that may require access to the $_SESSION variable using
2) 可能导致此问题的另一件事，可能是在所有可能需要使用 $_SESSION 变量访问的文件的顶部启动会话失败
session_start();
Hope this helps anybody that stumbles on the same problem. Although this is coming at a late hour.
希望这可以帮助任何遇到相同问题的人。虽然这是来晚了。
回答by learner_19
session_start() is the answer. And here's one more way of going about it:
session_start() 就是答案。这是另一种方法：
<?php
if (session_id() == "")
session_start(); ?>
This will ensure that a new session is started only if you do not have a current session on already. And ofcourse, as others have said, make sure to place this at the top of the html.
这将确保仅当您没有当前会话时才启动新会话。当然，正如其他人所说，确保将其放在 html 的顶部。
