When a Facebook user sends the Send dialog within an application, can the application track the recipients?

Question

When users open a Send dialog (e.g. http://www.facebook.com/dialog/send?app_id=123050457758183&name=People%20Argue%20Just%20to%20Win&link=http://www.nytimes.com/2011/06/15/arts/people-argue-just-to-win-scholars-assert.html&redirect_uri=http://www.example.com/response) they can add or remove people from the To: line.

Is there a way for the application to track who was in the To: line if and when the user actually pushes Send?

Answer 1

No. At least not currently...

If you look at the official documentation: https://developers.facebook.com/docs/reference/dialogs/send/ then you can see that this type of dialog does not expect a callback function as a parameter, and since there's no callback function then you have no way of knowing who and/or how many recipients were, and even if the dialog is closed/canceled/sent.

What you can do, though seems very complicated and well, a headache, is to use the outbox connection of the User object in the graph api (http://developers.facebook.com/docs/reference/api/user/). I've never used that before, but I guess that you can (if you ask for the read_mailbox permission) check the user messages before and after the dialog, and see what changed.