class HttpClientMiddleware

class HttpClientMiddleware {
    
    /**
     * @var array
     */
    private $completedRequests;
    
    /**
     * @var array
     */
    private $failedRequests;
    
    /**
     *
     */
    public function __construct() {
        $this->completedRequests = [];
        $this->failedRequests = [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function __invoke() {
        return function ($handler) {
            return function (RequestInterface $request, array $options) use ($handler) {
                // If on_stats callback is already set then save it
                // and call it after ours.
                if (isset($options['on_stats'])) {
                    $next = $options['on_stats'];
                }
                else {
                    $next = function (TransferStats $stats) {
                    };
                }
                $options['on_stats'] = function (TransferStats $stats) use ($request, $next) {
                    $request->stats = $stats;
                    $next($stats);
                };
                return $handler($request, $options)->then(function ($response) use ($request) {
                    $this->completedRequests[] = [
                        'request' => $request,
                        'response' => $response,
                    ];
                    return $response;
                }, function ($reason) use ($request) {
                    $response = $reason instanceof RequestException ? $reason->getResponse() : null;
                    $this->failedRequests[] = [
                        'request' => $request,
                        'response' => $response,
                        'message' => $reason->getMessage(),
                    ];
                    return \GuzzleHttp\Promise\rejection_for($reason);
                });
            };
        };
    }
    
    /**
     * @return array
     */
    public function getCompletedRequests() {
        return $this->completedRequests;
    }
    
    /**
     * @return array
     */
    public function getFailedRequests() {
        return $this->failedRequests;
    }

}