How to store some info while user is submitting rating with Fivestar module?
Submit handler was not working so I have decide to do it with validate handler like this


 
function recipe_form_alter($form, $form_state, $form_id) {
  if ($form_id == 'fivestar_custom_widget') {
    $form['#validate'][] = 'fivestar_rest_api';
  }
}

function fivestar_rest_api($form, $form_state) {
   $ch = curl_init("http://www.example.com/xxx");
   curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
   curl_setopt($ch, CURLOPT_HEADER, 0);
   $data = curl_exec($ch);
   curl_close($ch);
   $json = json_decode($data,true);
   $errorMessage = $json['errorMessage'];
   $errorCode = $json['errorCode'];
   $commands[] = ajax_command_remove('.field-name-field-fivestar-rating');
   $commands[] = ajax_command_append('#rating-wrapper', 'Thankyou for your rating.');
   return array('#type' => 'ajax', '#commands' => $commands);
 }



Now it is working fine form me.