[development] Add data to Drupal session

[Salvatore De Paolis]

Hi,

I'm new to this mailing list, I hope is the right place to ask for such
questions.
I'm writing a module for drupal which implements a jabber client and hooks in
the appbar module.
The issue i'm having now is regarding the data used for jabber communication.
I'm using a jabber class and I need to store this object somewhere so that the
_init code is just executed one time.
I thought about sessions and I found a couple of ways, both don't works
properly for me.

First is using the global $user:

function jwclient_jabberclass_init() {
   global $user;
   if (!isset($user->jabclient) && $user->uid) {
       require_once('jabber.php');
       ...
       $jab = New Jabber($debug);
       $jabclient = New JabberClient($jab);
       $jabclient->jabber_client_set_user($user);
       ...
       user_save($user, array('jabclient' => $jabclient));     
   }
}  
function jwclient_init() {
  jwclient_jabberclass_init();
  ...
}
function theme_jwclient_chat () {
  global $user;
  return $user->jabclient->status;
}

This solution gives me an errors of __PHP_Incomplete_Class Object. 
Googling in understood that a proper way to save classes in session is to
fistly define the class and than call session_start. I don't see ways to
achieve this since the class I'm using is defined in a module and the
drupal session is already initiated.
A workaround i found on drupal.org is by using serialize/unserialize but it
doesn't work around for this case.
I changed the code in this way:

function jwclient_jabberclass_init() {
   global $user;
   if (!isset($user->jabclient) && $user->uid) {
       require_once('jabber.php');
       ...
       $jab = New Jabber($debug);
       $jabclient = New JabberClient($jab);
       $jabclient->jabber_client_set_user($user);
       ...
       $jabclient = serialize($jabclient);
       user_save($user, array('jabclient' => $jabclient));     
   }
}  
function jwclient_init() {
  jwclient_jabberclass_init();
  ...
}
function theme_jwclient_chat () {
  global $user;
  $jabclient = $user->jabclient;
  $jabclient = unserialize($jabclient);
  return $user->jabclient->status;
}
The result is: warning: unserialize() expects parameter 1 to be string, object
given

After this, i give away $user and tried with $_SESSION

function jwclient_jabberclass_init() {
   global $user;
   if (is_null($_SESSION['jabclient']) && $user->uid) {
       require_once('jabber.php');
       ...
       $jab = New Jabber($debug);
       $jabclient = New JabberClient($jab);
       $jabclient->jabber_client_set_user($user);
       ...
       $_SESSION['jabclient'] = serialize($jabclient);
   }
}  
function jwclient_init() {
  jwclient_jabberclass_init();
  ...
}
function theme_jwclient_chat () {
  $jabclient = unserialize($_SESSION['jabclient']);
  return $jabclient->status;
}
This attempt works on the first call. On the second call I get again the error
about __PHP_Incomplete_Class Object.

I'm out of clue now.
Anyone know how to manage the case of storing objects in session with drupal?

Thanks,
Salvatore