Barryvdh\Cors\Stack\CorsService::addActualRequestHeaders PHP Method

    public function addActualRequestHeaders(Response $response, Request $request)
    {
        if (!$this->checkOrigin($request)) {
            return $response;
        }
        $response->headers->set('Access-Control-Allow-Origin', $request->headers->get('Origin'));
        if (!$response->headers->has('Vary')) {
            $response->headers->set('Vary', 'Origin');
        } else {
            $response->headers->set('Vary', $response->headers->get('Vary') . ', Origin');
        }
        if ($this->options['supportsCredentials']) {
            $response->headers->set('Access-Control-Allow-Credentials', 'true');
        }
        if ($this->options['exposedHeaders']) {
            $response->headers->set('Access-Control-Expose-Headers', implode(', ', $this->options['exposedHeaders']));
        }
        return $response;
    }

 /**
  * Render an exception into an HTTP response.
  *
  * @param  \Illuminate\Http\Request  $request
  * @param  \Exception  $e
  * @return \Illuminate\Http\Response
  */
 public function render($request, Exception $e)
 {
     if ($e instanceof ModelNotFoundException) {
         $e = new NotFoundHttpException($e->getMessage(), $e);
     } elseif ($e instanceof OAuthException) {
         $response = response()->json(['error' => $e->errorType, 'error_description' => $e->getMessage()], $e->httpStatusCode, $e->getHttpHeaders());
         return $this->corsService->addActualRequestHeaders($response, $request);
     }
     return parent::render($request, $e);
 }