How to receive third party POST data

Hi

I’m having a third party POST data to a URI in my EE site automatically on an order completion.

I know how to manipulate the data once I’ve got it, but I don’t know how to code the receiving file/template.

I currently have the following PHP in an EE template to receive the data:

<?php
 $salt  = '123456abcdef';
 $order_src = 'source_name';
 $chk_order_key = sha1($order_src.$salt);
 $order_key  = ee()->input->post('order_key', FALSE);
 $order_ref  = ee()->input->post('order_ref', TRUE);
 $order_value  = ee()->input->post('order_value', TRUE);
 $order_name = ee()->input->post('order_name', TRUE);
 $order_ip  = ee()->input->post('order_ip', TRUE);

 if($order_key!=$chk_order_key)
 {
  echo 'failed';
 } else {
  echo 'success!';
 }
?>

…but testing with a form just throws up an EE error - presumably relating to the lack of an XID on submit.

So, do I need to setup a separate standalone PHP file to receive the data and insert the data into the EE database outside of EE? Or do I need to create an EE module or something?

I’m not sure what to do, so any help would be appreciated 😊

Thanks Steve