How do I get secure AuthSub session tokens in PHP ?

Question

I am using the Google/YouTube APIs to develop web application which needs access to a users YouTube account.

Normal unsecure requests work fine and I can upgrade one time tokens to session tokens without any hassle. The problem comes when I try and upgrade a secure token to a session token, I get:

ERROR - Token upgrade for CIzF3546351vmq_P____834654G failed : Token upgrade failed. Reason: Invalid AuthSub signature.

i use this:

    function updateAuthSubToken($singleUseToken)
    {
        try {
        $client = new Zend_Gdata_HttpClient();
        $client->setAuthSubPrivateKeyFile('/home/myrsakey.pem', null, true);
        $sessionToken = Zend_Gdata_AuthSub::getAuthSubSessionToken($singleUseToken, $client);
        $sessionToken = Zend_Gdata_AuthSub::getAuthSubSessionToken(trim($singleUseToken), $client);  
        //$client->setAuthSubToken($sessionToken); 
        } catch (Zend_Gdata_App_Exception $e) {
            print 'ERROR - Token upgrade for ' . $singleUseToken
                . ' failed : ' . $e->getMessage();
            return;
        }
        $_SESSION['sessionToken'] = $sessionToken;
        $date = gmdate("M d Y H:i:s", mktime(0, 0, 0, 1, 1, 1998));
        header('Authorization: AuthSub token="'.$_SESSION['sessionToken'].'" data="GET 
    https://www.youtube.com/auth_sub_request '.$date.' 15948652339726849410" '. 
    'sig="MIICXAIBAAKBgQDLJn/sr7TrmQpsEaL312k9dEpikVGFHbE+FjNg7/lfagkTZXf3'.
    't96omgSEyZat2RcckVAGs9dU5kbGLJxEaW2ChQplzCKDi+20HZZo7C1QCluaMJ6b'.
    ...
    '0pj+zWPy4T04PH3elN6EkhQ5Vxy5wbBkugqIDqfOKuM=" '.
    'sigalg="rsa-sha1"');
        }

i don't understand what is: nonce: a random 64-bit, unsigned number encoded as an ASCII string in decimal! i must put is after $date (... '.$date.' 15948652339726849410" '... )

Answer 1

I believe the call you want is:

$sessionToken = Zend_Gdata_AuthSub::getAuthSubSessionToken($singleUseToken, $client);

Calling Zend_Gdata_AuthSub::AuthSubRevokeToken() will revoke your single use token. There's a great tip here that demonstrates the full secure AuthSub flow.