POST /?id={object-instance-id or object-url}&scrape=true

curl "http://developers.facebook.com/tools/debug/og/object?q=$url"

$config = array(
            "appId" => 'APP_ID',
            "secret" => 'APP_SECRET');

        $fb = new Facebook($config);
        $r=$fb->api('/','POST',array(
            'id'=>PAGE_URL,
            'scrape'=>'true'
        ));