How Can I Determine if a Facebook User Likes My Page Using its API?

Determining User Affinity Towards a Facebook Page Using Its API

Facebook offers a means to ascertain whether a user has expressed their appreciation for your page. However, this functionality can be elusive, leaving you scratching your head.

One method, using FB.api, requires an extended permission grant from the user, which may not be your desired approach.

Alternative Solution:

Consider leveraging OAuth 2.0 for Canvas, an advanced option. When activated, Facebook furnishes you with a $_REQUEST['signed_request'] for every page accessed within your tab app. Parsing this request reveals crucial information about the user, including their affinity towards your page.

function parsePageSignedRequest() {
    if (isset($_REQUEST['signed_request'])) {
        $encoded_sig = null;
        $payload = null;
        list($encoded_sig, $payload) = explode('.', $_REQUEST['signed_request'], 2);
        $sig = base64_decode(strtr($encoded_sig, '-_', '+/'));
        $data = json_decode(base64_decode(strtr($payload, '-_', '+/'), true));
        return $data;
    }
    return false;
}
if($signed_request = parsePageSignedRequest()) {
    if($signed_request->page->liked) {
        echo "This content is for Fans only!";
    } else {
        echo "Please click on the Like button to view this tab!";
    }
}

By implementing this approach, you can accurately determine whether a user has bestowed their love upon your page without the need for additional permissions.

The above is the detailed content of How Can I Determine if a Facebook User Likes My Page Using its API?. For more information, please follow other related articles on the PHP Chinese website!