pipeline.php

class Pipeline implements RequestHandlerInterface
{
    public function __constuct($handlers)
    {
        $this->handlers = $handlers;
    }

    public function handle(Request $request): Response
    {
        $handler = current($this->handlers);

        next($this->handlers);

        if ($handler intanceof MiddlewareInterface) {
            return $handler->process($request, $this);
        }

        if ($handler intanceof RequestHandlerInterface) {
            return $handler->handle($request);
        }

        return call_user_func_array($handler, [$request, $this]);
    }
}