php - Help w/ Codeigniter session expiration time -

i dynamically set session expiration time in codeigniter. i'm autoload session class. have view contains checkbox users click (remember me). right if click check box or not expiration time stays same :/

     // config.php     $config['sess_expiration']      = 7200;      // controller     if ($this->input->post('remember_me') == 'true')     {     $this->session->remember_me();     }      $newdata = array(     'failed_login'  => 0,     'user_name'  => $this->input->post('user_name'),         'logged_in' => true     );      $this->session->set_userdata($newdata);      // my_session.php     class my_session extends ci_session {      function remember_me()     {         $this->sess_expiration = 172800;     }      } 

if need implement "remember me" feature - you've started in wrong way.

you need create 1 more database table fields user_id | token.

then, after user has been logged in (with "remember me" checkbox checked on) - generate random token , insert new row current user_id , token. - set remember cookie same token value.

now, if user enters site, not authenticated , has token - can find token , authenticate user (each token unique , strognly related specific user_id).