[Plugin: kk Star Ratings] Integration with Facebook

You can do a simple check if user is logged in with Facebook via the Facebook API and then display the specific kk star ratings-shortcode to those users.

Using the Facebook PHP SDK:

if ($session) {
  try {
    $me = $facebook->api('/me');
    if ($me) {
      //User should be logged in
      echo do_shortcode('[kk_star_ratings]');
    }
  } catch (FacebookApiException $e) {
     //User is not logged in
     echo "Log in with Facebook to rate this post";
  }
}