Facebook Application Tab -> External Linking with PHP

Question

I currently have an Application on the Facebook Tab, and am wondering if there is a way for me to deep link into an item on that app tab. Example:

User is in the application (which is searching books), finds a book they like, and wants to share it with a friend. They click to share it, and I can pull all the info, however I don't have a deep link so when it's emailed, facebooked, ect.. it sends the user directly to the page with it on it.

Is this possible on the Application Tab? I know on the canvas I could deep link fine... but looking for a way to do it on the App Tab.

Thank you for your thought and responses.

Answer 1

Here's how we deep link to subpages within our app's Page Tab.

When your application lives inside a Page Tab, Facebook will strip out all GET params except for app_data. It passes app_data inside the signed_request parameter of the POST data.

More info in the docs: https://developers.facebook.com/docs/authentication/signed_request/

So when we build links to subpages, it will look something like

http://www.facebook.com/myfanpage?sk=app_XXXXXX&app_data=%2Fmainpage%2Fsubpage

Then, in our index page code, we check for the app_data param. If it exists, then a simple 302 redirect does the trick.

$request = parse_signed_request($_POST['signed_request']);
if ($request['app_data'])
{
    header('HTTP/1.1 302 Found');
    header('Location: {$request['app_data']}');
    exit;
}

Note: you can pass more than 1 param inside of app_data using a URL-encoded, JSON-array or something like that.

Answer 2

Perhaps.

For Application Canvas Pages, Facebook forwards any addition URI information to your canvas callback.

For example, if your app page is http://apps.facebook.com/testapp

and your canvas callback is http://facebook.example.com/testapp/canvas

Then going to http://apps.facebook.com/testapp/foo?bar=baz would result in facebook's servers hitting yours like so http://facebook.example.com/testapp/canvas/foo?bar=baz.

I've never tested it to see if application tabs share this behavior, but it's worth a shot. If so, you could just use URI information to drive your deeplinking.

Also, you should be aware of the impending changes to application tabs.