Get member id in ExpressionEngines session hook

Question

How do I get the member id of the current user in my extension when I'm in the session_start hook?

ee()->session->userdata('member_id');

Obviously doesn't work; this gives me a server error.

Answer 1

First initial thought is: can you use sessions_end hook instead?

Looking at the Session.php code for where the session_start is fired, this hook kicks in before the user data is set from the cookie/session as the next lines that come after the hook are:

// Set the validation type
$this->validation = (REQ == 'CP') ? ee()->config->item('cp_session_type') : ee()->config->item('website_session_type');

Get the session type dependant on what is being accessed - the Control Panel or frontend.

// default to "cookies and sessions" if validation type doesn't exist or is invalid
if ( ! in_array($this->validation, $this->valid_session_types))
{
    $this->validation = 'cs';
}

Copying this into your code won't work due to usage of valid_session_types, so you could either replicate the valid types, or just assume 'cs' if the validation variable is not set.

// Grab the session ID and update browser fingerprint based on the validation type
// we use the same URL key whether it's getting the session ID or the browser fingerprint,
// simplifying URI parsing and complicating session hijacking attempts
switch ($this->validation)
{
    case 's'    :
        $this->sdata['session_id'] = (ee()->input->get('S')) ? ee()->input->get('S') : ee()->uri->session_id;
        break;
    case 'c'    :
        $this->sdata['session_id'] = ee()->input->cookie($this->c_session);
        break;
    case 'cs'   :
    default     :
        $this->sdata['session_id'] = ee()->input->cookie($this->c_session);
        $this->sdata['fingerprint'] = (ee()->input->get('S')) ? ee()->input->get('S') : ee()->uri->session_id;
        break;
}

The above is the key chunk, where it will get the session_id from the URL or from the cookie.

The EE core Session code then calls the fetch_session_data function which does the DB query to get the member details...

ee()->db->select('member_id, admin_sess, last_activity, fingerprint, sess_start, login_state');
ee()->db->where('session_id', (string) $this->sdata['session_id']);

Main part of the query using the Session ID we got above.

// We already have a fingerprint to compare if they're running cs sessions
// otherwise we'll do it after fetching their member data, presuming the session ID is valid
if ($this->validation == 'cs')
{
    ee()->db->where('fingerprint', (string) $this->sdata['fingerprint']);
}

Not too sure if you'll need this, as it refers to fetching it later, but useful if the user has multiple sessions open in different browsers maybe...?

$query = ee()->db->get('sessions');
if ($query->num_rows() == 0 OR $query->row('member_id') == 0) {
    //FAILED TO FIND SESSION
    return false;
}

Run the query, do checks on the result and...

$memberID = (int) $query->row('member_id');

Finally you have the member ID.