Facebook画布URL重定向到https

Question

I have a Facebook app with both, canvas url and secure canvas url.

When my user opens the app within a page tab, my app reads the signed_request with the page id and delivers content for this specific FB page.

When my user uses https surfing in FB logs out and the next user logs in with only http surfing, my app gets redirected to the secure canvas url and my signed_request parameter is lost . Without the signed_request parameter I can't determine which page should be served by my app.

When I empty the browser cache , the right http URL of my app is used.

Is there a way to always use https with FB apps, or prevent the browser from caching the https URL?

Thanks!

Answer 1

If you want to redirect from http to https and not lose the signed_request POST parameter, you can manually snag it before the redirect and append it to the URL as a GET parameter. See below!

// Force SSL
if(443 != $_SERVER['SERVER_PORT'] || 'on' != $_SERVER['HTTPS'])
{
    $queryString = $_SERVER['QUERY_STRING'];
    $hadQueryString = '' == $queryString ? false : true;
    $baseUrl = $_SERVER['REQUEST_URI'];
    $questionMark = strpos($_SERVER['REQUEST_URI'], '?');

    if(false !== $questionMark)
    {
        $baseUrl = substr($_SERVER['REQUEST_URI'], 0, $questionMark);
    }

    if($hadQueryString && isset($_REQUEST['signed_request']))
    {
        $queryString = $_SERVER['QUERY_STRING'] . '&signed_request=' . $_REQUEST['signed_request'];
    }
    elseif(isset($_REQUEST['signed_request']))
    {
        $queryString = 'signed_request=' . $_REQUEST['signed_request'];
    }

    $newLocation = 'https://' . $_SERVER['HTTP_HOST'] . $baseUrl . '?' . $queryString;

    header('HTTP/1.1 301 Moved Permanently');
    header('Location: ' . $newLocation);
    exit();
}