I'm using SSO with my Wordpress site and FoxyCart. On my site, users are able to purchase videos that they watch online. If a user is not logged in, they click "Buy" on the video, get redirected to the authentication endpoint to sign in, and then get redirected back to the checkout page. However, before I redirect them to checkout, I want to make sure that they haven't already purchased the video. To accomplish this, I redirect to a PHP script from the login page before redirecting to the checkout page. In this PHP script, I want to retrieve the user's cart using PHP CURL and compare it against my own database. I tried using the method described in http://wiki.foxycart.com/v/1.0/json
, but an empty cart is returned every time. Any idea on how this can be accomplished?