I have integrated Smartsheet api in PHP, i am able to create the webhook and enable it. When a change is made in the sheet it hits the callback url. I am not receiving any data related to the change. I have logged the data as $_POST which is empty.
function smartWebhook_post(){
log_message('error','SS data: '.print_r($_POST,true), '', 'smartsf');
$this->response(array('HTTP status'=>200));
}
According to the documentation HTTP status 200 has to be sent back.