PayPal\Service\PayPalAPIInterfaceServiceService::DoAuthorization PHP Method

    public function DoAuthorization($doAuthorizationReq, $apiCredential = null)
    {
        $apiContext = new PPApiContext($this->config);
        $handlers = array(new PPMerchantServiceHandler($apiCredential, self::$SDK_NAME, self::$SDK_VERSION));
        $this->setStandardParams($doAuthorizationReq->DoAuthorizationRequest);
        $ret = new DoAuthorizationResponseType();
        $resp = $this->call('PayPalAPIAA', 'DoAuthorization', $doAuthorizationReq, $apiContext, $handlers);
        $ret->init(PPUtils::xmlToArray($resp));
        return $ret;
    }

* `Transaction ID` - Value of the order's transaction identification
number returned by PayPal.
* `Amount` - Amount to authorize.
*/
$doAuthRequest = new DoAuthorizationRequestType($_REQUEST['transID'], $amount);
$doAuthReq = new DoAuthorizationReq();
$doAuthReq->DoAuthorizationRequest = $doAuthRequest;
/*
 *  ## Creating service wrapper object
Creating service wrapper object to make API call and loading
Configuration::getAcctAndConfig() returns array that contains credential and config parameters
*/
$paypalService = new PayPalAPIInterfaceServiceService(Configuration::getAcctAndConfig());
try {
    /* wrap API method calls on the service object with a try catch */
    $doAuthResponse = $paypalService->DoAuthorization($doAuthReq);
} catch (Exception $ex) {
    include_once "../Error.php";
    exit;
}
if (isset($doAuthResponse)) {
    echo "<table>";
    echo "<tr><td>Ack :</td><td><div id='Ack'>" . $doAuthResponse->Ack . "</div> </td></tr>";
    echo "<tr><td>TransactionID :</td><td><div id='TransactionID'>" . $doAuthResponse->TransactionID . "</div></td></tr>";
    echo "</table>";
    echo "<pre>";
    print_r($doAuthResponse);
    echo "</pre>";
}
require_once '../Response.php';