如何识别用户使用的DEVELOPER_DEFINED_PAYLOAD

Question

I am creating a chatbot using the messenger. How do I know that the user clicked on my button

"buttons":[
  {
    "type":"postback",
    "title":"Bookmark Item",
    "payload":"DEVELOPER_DEFINED_PAYLOAD"
  }
]

To receive am using the following code

if(preg_match('[hello]', strtolower($message))) {
$message_to_reply = 'Welcome';}

Answer 1

When button is tapped, Facebook will trigger the postback received callback and deliver the person's page-scoped ID (PSID). You can then present a personalized message to greet the user or present buttons to prompt him or her to take an action.

You can subscribe to this callback by selecting the messaging_postbacks field when setting up your webhook.