Destroy Session but keep flashdata - php

Question

I am using Tank Auth for user management in my CI 1.7.3 App. Everything is working fine but I'm trying to set a flash_message to be displayed when the user logs out. The problem is the $this->tank_auth->logout(); function destroys the session. I have modified the logout function in the Tank Auth library to look like:
function logout() {
$this->delete_autologin();
// See http://codeigniter.com/forums/viewreply/662369/ as the reason for the next line
$user_session_data = array('user_id' => '', 'username' => '', 'status' => '');
$this->ci->session->set_userdata($user_session_data);
$this->ci->session->unset_userdata($user_session_data);
}
It was previously
function logout()
{
$this->delete_autologin();
// See http://codeigniter.com/forums/viewreply/662369/ as the reason for the next line
$this->ci->session->set_userdata(array('user_id' => '', 'username' => '', 'status' => ''));
$this->ci->session->sess_destroy();
}
In My controller I have
function logout(){
if ($this->tank_auth->is_logged_in()) { // logged in
$this->session->set_flashdata('status_message', $this->lang->line('auth_message_logged_out'));
$this->tank_auth->logout();
redirect('');
}
}
If I remove the $this->tank_auth->logout(); function the message shows fine. I'm sure it's a simple session problem

Answer 1

If you try to set flashdata while using a database in the same request after you call sess_destroy(), it won't work (because there is no session to append the flashdata to).
To fix this problem, add $this->ci->session->sess_create(); after the call to sess_destroy(). This works because you're re-creating the session before trying to append data to it. This is the only way to use flashdata after a sess_destroy() if you're using sessions in a database.

Answer 2

The sess_destroy() function destroys also the session flash variables used to pass the message.
U already answered your question, in the library logout() function, you need to replace
$this->ci->session->sess_destroy();
with
$this->ci->session->unset_userdata(array('user_id' => '', 'username' => '', 'status' => ''));
This will not completely destroy the session, only the user data used for login, so I recommend instead, to modify the logout() function in the controller and show the message manually, by passing it to a view.

Answer 3

While this is a workaround, it might do the trick for you...
wherever you're displaying these, I'll be assuming you're checking in the view so...
<? if ($this->session->flashdata('status_messege'): ?>
<p><?= $this->session->flashdata('status_message') ?></p>
<? endif; ?>
you COULD add an elseif to that and check for the referrer being your logout function...
<? if ($this->session->flashdata('status_messege'): ?>
<p><?= $this->session->flashdata('status_message') ?></p>
<? else if ($this->agent->referrer() == site_url('path/to/logout'): ?>
<p><?= $this->lang->line('auth_message_logged_out') ?></p>
<? endif; ?>
A bit of a hackish way to overcome this issue, but probably a way nonetheless.