I currently have successfully set up a topic and subscription in the google cloud platform, and have verified my site with google and added the domain to the GCP.
Whenever I try to send a test message from https://console.cloud.google.com/cloudpubsub/topics/subscription_sync, the endpoint I configured receives something, but the POST variable is empty. Here is the code I have so far in php, it just does simple logging of the POST variable (which later shows up in my logs as empty.)
require_once 'EventPersister.class.php';
$eventPersister = new EventPersister(EventPersister::GOOGLE_WEBHOOKS);
$eventPersister->Persist($_POST);
Is there anything special I need to do to get the POST data to show up properly?