Quick fix for RequestHandler when used as a middleware.

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.0.1] - 2019-07-15
+### Fixed
+- When RequestHandler was used as a middleware, default RequestHandler was not saved and wrong default request handler 
+was called.
+
 ## [2.0.0] - 2019-07-12
 ### Added
 - RequestHandler supports MiddlewareInterface to be use as a middleware as well

src/RequestHandler.php

@@ -86,6 +86,10 @@ public function handle(ServerRequestInterface $request): ResponseInterface
 
     public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
     {
+        if (!isset($this->defaultRequestHandler)) {
+            $this->defaultRequestHandler = $handler;
+        }
+
         if ($this->middlewareCollection->isEmpty()) {
             return $handler->handle($request);
         }