Facebook sends empty POST to a webhook

Question

I am trying to install a webhook for leadgen event for my page via a facebook app. So I have:

1. Facebook Page where leads come from
2. Facebook App
<

Answer 1

In case you are using the django framework, you should request.body, as post data will remain empty.

def webhook_response(request):
   # it will print the contents from facebook webhook response
   print(request.body)

   # something like the following object will print up if you are using leadgen
   {"object": "page", "entry": [{"id": "0", "time": 111111111, "changes": [{"field": "leadgen", "value": {"ad_id": "444444444", "form_id": "444444444444", "leadgen_id": "444444444444", "created_time": 11111111, "page_id": "444444444444", "adgroup_id": "44444444444"}}]}]}

Answer 2

Facebook sends webhook data as Content-Type: application/json, not as …: application/x-www-form-urlencoded (as a normal form with method=post would.)

Therefor, PHP does not populate $_POST – you need to read the raw input stream instead. That can be done using file_get_contents('php://input') – and then just apply json_decode on that data, and you’ll have a proper data structure to work with.

Answer 3

This code works for me...

if (!empty($_REQUEST['hub_mode']) && $_REQUEST['hub_mode'] == 'subscribe' && $_REQUEST['hub_verify_token'] == "<mytoken>") {
    echo $_REQUEST['hub_challenge'];
} else {
    $data = json_decode(file_get_contents("php://input"), true);
    file_put_contents('logFB.txt', print_r($data, true));
}  

First part is for verifying webhook, second for getting data from facebook webhook.

Hope this will help...

Answer 4

Facebook sends the leads data in the request body. If you are using a framework, please check if you have access to the request body. Try using a third party intermediate service like Runscope to see the full request, it is very usef