Question

In the context of a given Facebook app, suppose User A invited user B to start using it. Once User B accepts to use the app, is there any way to retrieve the ID of User A programmatically (via either PHP/JS SDK) ? This doesn’t seem quite documented.

For what it’s worth, A/B users are friends, if it’s any use.

Answer 1

when user comes following the app request, you can get request id’s using

$_GET['request_ids']

then retrieve all the request ids with which you can call graph api to get the corresponding request details like below:

if(isset($_GET['request_ids']))
     {
          $request_ids = $_GET['request_ids'];
      }
$request_ids = explode(",", $request_ids);
foreach($request_ids as $request_id)
       {
            $request_object = $facebook->api($request_id);
             //this $request_object have sender facebook id in the field uid_from
        }