Quick way to find out if a user is subscribed to a list in Campaign Monitor API

Question

Does anyone know if there is a way of checking a subscribers status on a list.

The only way I can see to do it is loop through the active and unsubscribed subscribers on a list and see if it matches. Obviously this is not very efficient if there are 10's of thousands of subscribers.

What I'm trying to do is have a form on a site that allows you to unsubscribe or subscribe to a mailing list. I'd like this to check Campaign Monitor to see which lists they are subscribed to and precheck those boxes.

Answer 1

Use Client.ListsForEmail to get all the lists for a given email address, and then once you have the lists you should be able to check the status of the subscriber in each of those

Answer 2

You can do it like that -- checking if the subscriber exists in a list -- but it's easier to do it the other way, by checking if a list has a given subscriber. Like this:

function is_subscribed_to_list($list_id, $email_address) {
    require_once('createsend-php/csrest_lists.php');
    $auth = array('api_key'=>$this->api_key);
    $wrap = new CS_REST_Clients($client_id, $auth);
    $result = $wrap->get_lists_for_email($email_address);
    $list_subscriptions = (array) $result->response;
    return array_key_exists($list_id, $list_subscriptions);
}