Facebook: Link Request's sender to it's recipient? - facebook

Question

When using the requests dialog, facebook issues a notification like this:
What I'm looking to achieve is for the user to click the request link shown above and to present a "Random User invited you to..." message on our App.
However, when clicking that link Facebook doesn't seem to pass through the id of "Random User" to the App. The url accessed by the link looks something like:
http://apps.facebook.com/randomcomp/?fb_source=notification&request_ids=350578327437399,350578327437399&ref=notif&app_request_type=user_to_user&notif_t=app_request
which doesn't contain any reference to the user who initiated the request.
From the App's side, there doesn't seem to be a way to get this information from Facebook. Sure, you can get a list of requests, but that list can contain information for many requests, including requests from other users in addition to the one we're interested in, so it's not useful in this case. For example, here's a snapshot of data:
{
"data": [
{
"id": "340083146057323_100003817986566",
"application": {
"name": "Random Competition",
"namespace": "randomcomp",
"id": "350578327437399"
},
"to": {
"name": "Hannah Smith",
"id": "100003817986566"
},
"from": {
"name": "Random User",
"id": "100002286042525"
},
"data": "100002286042525",
"message": "Use the app!",
"created_time": "2012-05-14T13:26:30+0000"
}, {
"id": "358318457550141_100003817986566",
"application": {
"name": "Random Competition",
"namespace": "randomcomp",
"id": "350578327437399"
},
"to": {
"name": "Hannah Smith",
"id": "100003817986566"
},
"from": {
"name": "Jane Young",
"id": "100003771838663"
},
"data": "100002286042525",
"message": "Use the app!",
"created_time": "2012-05-14T10:54:25+0000"
}],
}
}
As you can see, the data is being passed in, but there's still no way to join the click from the link mentioned above (for Random User) to the correct request in the list; the link passes through the ID for both requests, not just the one for Random User, and while the link states "Random User" it doesn't pass through an identifier.
Am I missing something? Is there a mechanism that isn't in the docs that will allow me to pick-up the "Random User" id so I can provide a nice "Random User invited you to..." message in the App when they click through?
Edit:
Turns out that this isn't possible - see my answer.

Answer 1

You can add some data to the request so that when you process the request you can differentiate that from other requests.
The data can be sent with app requests and users requests and the parameter name is "data".
For example, in the guide for the Requests Dialog you can see it in the properties table at the (almost) end of the document, it says:
Optional, additional data you may pass for tracking. This will be
stored as part of the request objects created. The maximum length is
255 characters
There's also some info about it in the Social Channels documentation, and a sample of (php) usage in the official blog post about Upgrade to Requests 2.0.
I hope that this is what you're looking for.
Edit
When you send the request you know who is sending it right? It's the logged in user, and so you can put the user id/name/etc in the data parameter of the request.
Then, when someone clicks on a request, get the request by the id that facebook passes to you, and from the data extract the user id of the sender.
As the documentation states, you have 255 characters to use, and with that you can do what ever you want, you can even serialize an object to that parameter and deserialize it later.

Answer 2

As it turns out, this is in fact not possible at all.
The link, as shown in the image below, can present multiple users:
which is why multiple request IDs are passed in, and the sender's ID isn't.