Capture details of Facebook message in application database

In my Facebook application I am d开发者_如何学Cisplaying a message window using FB.ui { method: 'send' ...}. I would like to capture the list of recipients (stored in the 'recipitents []' hidden form field) as well as the message text in my application database.

Is there a way to do that?

Here's what I have come up with so far:

1. Dynamically set the onclick attribute in the DOM element (which corresponds to the Send button. So far I have been able to do that using the browser development tools (e.g. F12 in IE9) but not in code; it could be tricky since the dialog doesn't exist at load time). Unfortunately I haven't been able to define a Javascript function that was in the right scope (I thought there was only a global scope) for the onclick callback to find it.

2. Construct the Facebook Send dialog from more elementary building block (e.g., friend picker, send method invocation) so I 'own' the click event.

3. Clone the FB.ui() code and modify it to include additional parameters when calling the redirect url.

4. Require the user to include me in the To list (really only last resort), or default the 'to' field to the application's user id.

Finally, I expect to be able to call my web service from Javascript to record the message details in my application database.

I'm pretty sure this is not available via the API by design. The Send button operates in an iframe so browser security will prevent you from accessing its internal state via Javascript.

Some other methods (such as using FB.ui dialogs to post to the user's wall) provide a post ID in the callback and you can check this in the Graph API, but the Send button doesn't return anything like this.

For the Send button you can subscribe to the message.send event in the Javascript SDK and receive a callback with the URL which was sent, but not who it was sent to. ( https://developers.facebook.com/docs/reference/javascript/FB.Event.subscribe/ - the event itself isn't currently listed there, but does exist)

I can't think of why you'd want to do this type of tracking, it seems like a use-case with very few policy compliant applications.