How to Detect a user declining a permissions request dialog that redirects to a Facebook TAB application

I posted this on the Facebook Dev forum and heard crickets...hopefully stackoverflow is a better bet.

This question is regarding the request permissions dialog being spawned from within a Facebook Application Tab specifically (not a canvas application).

If a user clicks "Allow", or "Don't Allow" the user is redirected to the same URL as specified in the redirect_uri parameter.

If the case of a canvas application I can use the error information that is passed in the URL to distinguish between the user who has accepted or declined the permissions request.

However, if the redirect URI specifies an Page TAB Application (and not a canvas app) I cannot pass this information into the iframe -- the only thing that gets passed through is the app_data parameter through the signed request parameter. (I can set the app_data parameter with the redirect_uri but since this is the same if a user accepts or rejects the permissions dialog, its of no help)

If anyone could let me know if its possible for a Tab Application to "know" if a user clicks "Don't Allow" within a request permissions dialog (or has any other suggestion) I would be ve开发者_如何学编程ry grateful!

Thanks very much

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I don't think you can do what you require within a Facebook tab using a login url. Have you considered using the JavaScript SDK instead?

FB.login(
    function(response) {
        if (response.session) {
            if (response.perms) {
                // user is logged in and granted permissions
            } else {
                // user is logged in, but did not grant any permissions
            }
        } else {
            // user is not logged in
        }
    }, {perms:'list,of,permissions'} // if required eg {perms:'publish_stream, email'}
);