How to make session variables unique per every php-script instance?

 <?php
        //Start session
        session_start();
        //Check whether the session variable SESS_MEMBER_ID is present or not
        if (!isset($_SESSION['id']) || ($_SESSION['id'] == '')) {
            header("location: index.php");
            exit();
        }

        $session_id=$_SESSION['id'];
        ?>

and file connection

 <?php

 class DbConnector {

 var $theQuery;
 var $link;

 function DbConnector(){

    // Get the main settings from the array we just loaded
    $host = 'localhost';
    $db = '';
    $user = 'root';
    $pass = '';

    // Connect to the database
    $this->link = mysql_connect($host, $user, $pass);
    mysql_select_db($db);
    register_shutdown_function(array(&$this, 'close'));

}

   //*** Function: query, Purpose: Execute a database query ***
function query($query) {

    $this->theQuery = $query;
    return mysql_query($query, $this->link);

}

//*** Function: fetchArray, Purpose: Get array of query results ***
function fetchArray($result) {

    return mysql_fetch_array($result);

}

//*** Function: close, Purpose: Close the connection ***
function close() {

    mysql_close($this->link);

}

}

?>

• generate a unique id for every page opened
• pass that unique id to the script via get method
• use that unique id instead of the script's name

problems with this approach

using this approach the session variables stored may take up very very much space over time if you don't clear the unused ones and the user opens your site a lot before the session expires

solution to these problems

• store a timestamp for every unique id generated
• change that timestamp to the current timestamp every time the user performs an action* on the page that uses that unique id
• if the user performs an action* in a page with another unique id, check if x time has elapsed since last action for every unique id, if yes, delete it

*: actions that can be performed on the page and page refresh

You can do this using session_name($unique_script_instance_name) - https://www.php.net/manual/en/function.session-name.php

All you need to do is to define a unique name for each instance of your script, so that for example if you have 2 separate installations of your application on a shared server, you provide name A for one and B for second, you can store this value as $unique_script_instance_name.

Then before you call session_start() you need to call session_name()

// One script
$unique_script_instance_name "A";
session_name($unique_script_instance_name);
session_start();

...

// Second script
$unique_script_instance_name "B";
session_name($unique_script_instance_name);
session_start();

...

That way both scripts will have its own session "domain" and will be isolated from each other. That way

Remember that a session is just a variable. You can definitely create a unique session variable for each page. For each get request a new unique session variable will be created. All you need to do is to create sessions' names unique.

<?php
 session_start();
 $_SESSION[$_GET['pid'].'_p1'] = "a session value";
 $_SESSION[$_GET['pid'].'_p2'] = "a session value";
 $_SESSION[$_GET['pid'].'_p3'] = "a session value";
?>

So for example, if you visit http://example.com/?pid=1232

The session name will be something like $_SESSION['1232_p1'];

For each get request a new unique session will be created.

To see all your session variables, use this code at the end of your page:

<?php
echo '<pre>';
print_r($_SESSION);
echo '</pre>';
?>

This is a very old question, but I am writing it for the use of other programmer or novice friends.

Just set a validation page for every request from client to check session variables. for example: valid_ref.php Or use a reference page for all page in your source code and call other pages according to client requests in the reference page.for example: index.php or home.php or ref.php in valid_ref.php check if $_SESSION[SCRIPT_NAME]['filter_data'] was in session , when client open new tab your web app use Previous data in $_SESSION[SCRIPT_NAME]['filter_data']'s and with this way you dont have any problem with new tabs in browsers from one client.