How get the notification ID when user enter in you app - facebook

Question

I'm using the Facebook requestdialog to show my friend list and invite,this in a Facebook Web APP, using this:
function sendRequestViaMultiFriendSelector() {
FB.ui(
{
method: 'apprequests',
message: 'Selección de amigos a los que invitar a KugaBar'
}, requestCallback);
}
function requestCallback(data) {
console.log(data);
}
It works (ok).
But I need to identify the user when enter in my APP, you see the requestCallback data and see a "request", but when the users click on the notification and enter in the APP
I don't know how identify the request to detect if the user is accessing by the notification.
EDIT: OK I found it.
The param in the GET vars are "request_ids", but one problem appear, this param only come if the user previously have accepted the permissions, if the user clicks on the notification, and accept the permissions, hitting enter: this param doesn't exist, if the user enter again (not need to accept nothing) this param exists in the URL.
Are there any method to get this param in the first time the user enter?
Thanks

Answer 1

When the user first clicks on a request, you should get the request_id from the URL and store it in a cookie. When the user has completed logging in, check if the cookie exists and then update your record accordingly.

Answer 2

Notifications and Requests are NOT the same thing on Facebook. In your case you're talking about Requests. Request ids are passed to the app as a GET parameter 'request_ids' which is a comma separated list.
To be able to access this parameter after login dialog, you want to save your GET parameters from the original launch URL before redirecting to the OAuth dialog and pass them around in the redirect URL. This way you solved this problem for all of your future GET parameters.
If you're using PHP, the function you're looking for is http_build_query. I'd highly discourage from using a cookie to store one-time and easily accessible URL parameters.