How to get formId of leadgen webhook on facebook?

问题

I have created webhook for tracking of leads on my facebook page. I need formId of lead but my logs shown as below.

[field] => leadgen
      [value] => stdClass Object
            (
              [ad_id] => 0
              [form_id] => 2.6147643765585E+14
              [leadgen_id] => 2.6356365078047E+14
              [created_time] => 1491489109
              [page_id] => 4.3192338381483E+14
              [adgroup_id] => 0
            )

[form_id] is shown like 2.6147643765585E+14 but actual formId is different.I think it is in encoded form right?

How to get formId in decoded form, I mean original formId like

 "field" => "leadgen",
      "value" => array(
        "leadgen_id" => 123123123123,
        "page_id" => 123123123,
        "form_id" => 12312312312,
        "adgroup_id" => 12312312312,
        "ad_id" => 12312312312,
        "created_time" => 1440120384
      )

Thanks in advance..

来源：https://stackoverflow.com/questions/43269606/how-to-get-formid-of-leadgen-webhook-on-facebook