Can I make an app available only to people that like a facebook page?

Question

I have made a facebook App and associated with a page. I only want people that like the page to be able to use the app. Is this possible?

Answer 1

When somebody tries to load your app, they will need to be authorised.

Once authorised, you can query the user's graph to see what they like:

(I've assumed you've authorised using the php sdk, and will have the $facebook object, however the principle is the same for other techniques)

    $fanPageId = "xxxxxxxxx";
    $appId = "xxxxxxxxxx";
    $fanPageLiked = false;
    $appLiked = false;

    $likes = $facebook->api('me/likes');

    foreach ($likes['data'] as $ilike) {
        if ($ilike['id'] == $fanPageId) {$fanPageLiked = true;}
        if ($ilike['id'] == $appId) {$appLiked = true; }
    }

    if ($fanPageLiked)
    {
    .... run your game.
    }
    else
    {
    .... redirect to fan page.
    }