I am learning the basic concept of how to manage login process and sessions. I take it that to logout a user, you need to destroy the session created for him. I was trying to find out how joomla 3.4 handles "logout" action to verify whether I have correctly understand what I have learned. But I have trouble finding out which PHP file is actually taking care of the "logout" logic. Here is what I do:

Firstly, I think no matter what fancy(to me) library or framework Joomla is using, down to bottom, there should be a file receiving "$_POST" datas, so I searched $_POST among all PHP files in my site, and I found this file "libraries/legacy/request/request.php" with this function

Class JRequest{
    public static function getVar($name, $default = null, $hash = 'default', $type = 'none', $mask = 0)
        // Ensure hash and type are uppercase
        $hash = strtoupper($hash);

        if ($hash === 'METHOD')
            $hash = strtoupper($_SERVER['REQUEST_METHOD']);

        $type = strtoupper($type);
        $sig = $hash . $type . $mask;

        // Get the input hash
        switch ($hash)
            case 'GET':
                $input = &$_GET;
            case 'POST':
                $input = &$_POST;
            case 'FILES':
                $input = &$_FILES;
            case 'COOKIE':
                $input = &$_COOKIE;
            case 'ENV':
                $input = &$_ENV;
            case 'SERVER':
                $input = &$_SERVER;
                $input = &$_REQUEST;
                $hash = 'REQUEST';

It seems to me Joomla has integrated "$_POST" data processing into this function so whenever Joomla wants to deal with user input, it will call this function. So I continue to search JRequest::getVar among all PHP files, I found only 1 occurence, which is in components/com_meida/views/medialist/view.html.php line 64

$dirname = JRequest::getVar('folder', '', '', 'string');

This doesn't look like having anything to do with login/logout processing. So I widen my search to just getVar, although there are many occurences, none of them looks like relevant and this is where I got stuck.

Could you please not only point out the PHP file I am looking for but also tell me what is wrong with my approach? Thank you in advance.

1 Answer 1


JRequest::getVar is an old deprecated method to get global variables which is no longer used in Joomla 3.x


Joomla has it's own framework which can be found here:


The file you're specifically looking for that deals with destroying the session is:

libraries/joomla/session/session.php line 682

See on Github here: https://github.com/joomla/joomla-cms/blob/staging/libraries/joomla/session/session.php#L682

As you can see, this calls $this->_handler->clear();, and the function for this is here: https://github.com/joomla/joomla-cms/blob/staging/libraries/joomla/session/handler/native.php#L243

This unsets and destroys the session


If you want to go further back before the session is dealt with, have a look at:

administrator/components/com_login/controller.php line 97

  • TYVM.I still want to know when users click "logout", what kind of global variable was sent and sent to where. I was trying to backtrace from that destroy() function in session.php. But it was very hard for me to debug this file: First I changed the name of the function, then when I click 'logout' I got an error, so its confirmed that this function was called when logging out. Then I insert echo 's'; into the destroy() as well as var_dump(debug_backtrace()), but none of them got any result to display on front end. I even try using j!dump to backtrace, but still got nothing.How debug it?
    – shenkwen
    Jan 29, 2016 at 0:24

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