未定义的变量：_SESSION通过JavaScript触发器发送变量时

Question

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.

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:

_SESSION is an undefined variable.

I've tried calling start_session() and session_regenerate_id() at the top of the second PHP file but the issue has persisted.

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')] .

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.

Answer 1

There's nothing special whatsoever about POST requests and sessions.
You just need to call session_start at the top of every file request you want to use sessions in, that's it.

Try again with that in mind, it ought to work.

Answer 2

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

    if (version_compare(PHP_VERSION, '5.4.0', '<')) {
        if(session_id() == '') {session_start();}
    } else  {
       if (session_status() == PHP_SESSION_NONE) {session_start();}
    }

Answer 3

我遇到了这个问题，在尝试了很多东西之后，我只在第二个脚本中包含了session_start（）并且它有效。

Answer 4

you must include

<?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)

If you're wanting to get values from a $_POST you could relate the two together by :

$_SESSION['var1'] = $_POST['answer1']

Answer 5

Add the following code to the file browse.php:

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.

Answer 6

I also encountered the same problem recently. I could not access the contents of the $_SESSION variable.

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;

<?php
 $username = $_SESSION['username'];
 //do some logical operation!!!
?> 
<?php include("header.php");?>

instead of doing something like this

<?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

session_start();

Hope this helps anybody that stumbles on the same problem. Although this is coming at a late hour.

Answer 7

session_start() is the answer. And here's one more way of going about it:

<?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.

Answer 8

I had this problem and tried different ways and finally found a solution :

PHP is case sensitive , Use $_SESSION instead of $_session in all php files.certainly It works . Example :

<?php
session_save_path('tmp/'); (is not optional - it is mandatory)
session_start();
echo $_SESSION["s1"]."<br/>";
echo $_SESSION["s2"]."<br/>";
?>