Use response facttories in ErrorHandler and NotFoundHandler

CHANGELOG.md

@@ -6,6 +6,34 @@ Versions prior to 1.0 were originally released as `phly/conduit`; please visit
 its [CHANGELOG](https://github.com/phly/conduit/blob/master/CHANGELOG.md) for
 details.
 
+## 3.0.0alpha4 - TBD
+
+### Added
+
+- Nothing.
+
+### Changed
+
+- [#153](https://github.com/zendframework/zend-stratigility/pull/153) modifies
+  the first argument of the `Zend\Expressive\Middleware\ErrorHandler` and
+  `NotFoundHandler` classes. Previously, they each expected a
+  `Psr\Http\Message\ResponseInterface` instance; they now both expect a PHP
+  callable capable of producing such an instance. This change was done to
+  simplify re-use of a service for producing unique response instances within
+  dependency injection containers.
+
+### Deprecated
+
+- Nothing.
+
+### Removed
+
+- Nothing.
+
+### Fixed
+
+- Nothing.
+
 ## 3.0.0alpha3 - 2018-02-05
 
 ### Added

composer.json

@@ -20,6 +20,7 @@
     },
     "require": {
         "php": "^7.1",
+        "fig/http-message-util": "^1.1",
         "psr/http-message": "^1.0",
         "psr/http-server-middleware": "^1.0",
         "zendframework/zend-escaper": "^2.3"

docs/book/v3/migration.md

@@ -89,6 +89,15 @@ internal logic.
   `Psr\Http\Server\RequestHandlerInterface`, and provides a return typehint of
   `Psr\Http\Message\ResponseInterface`.
 
+- `ErrorHandler::__construct()` and `NotFoundHandler::__construct()`: the first
+  parameter of each constructor now expects a PHP `callable` capable of
+  returning a PSR-7 `ResponseInterface` instance (instead of typehinting
+  directly against `ResponseInterface`). This paves the way for usage with the
+  upcoming PSR-17 (HTTP Message Factories) specification, and simplifies re-use
+  of a dependency injection container service (as otherwise you would need to
+  specify a discrete service per class that expects a response prototype, due to
+  mutability of the response body).
+
 ### Class additions
 
 - `Zend\Stratigility\MiddlewarePipeInterface` extends

src/Middleware/ErrorHandler.php

@@ -75,19 +75,22 @@ final class ErrorHandler implements MiddlewareInterface
     private $responseGenerator;
 
     /**
-     * @var ResponseInterface
+     * @var callable
      */
-    private $responsePrototype;
+    private $responseFactory;
 
     /**
-     * @param ResponseInterface $responsePrototype Empty/prototype response to
-     *     update and return when returning an error response.
+     * @param callable $responseFactory A factory capable of returning an
+     *     empty ResponseInterface instance to update and return when returning
+     *     an error response.
      * @param null|callable $responseGenerator Callback that will generate the final
      *     error response; if none is provided, ErrorResponseGenerator is used.
      */
-    public function __construct(ResponseInterface $responsePrototype, callable $responseGenerator = null)
+    public function __construct(callable $responseFactory, callable $responseGenerator = null)
     {
-        $this->responsePrototype = $responsePrototype;
+        $this->responseFactory = function () use ($responseFactory) : ResponseInterface {
+            return $responseFactory();
+        };
         $this->responseGenerator = $responseGenerator ?: new ErrorResponseGenerator();
     }
 
@@ -155,7 +158,7 @@ public function process(ServerRequestInterface $request, RequestHandlerInterface
     private function handleThrowable(Throwable $e, ServerRequestInterface $request) : ResponseInterface
     {
         $generator = $this->responseGenerator;
-        $response = $generator($e, $request, $this->responsePrototype);
+        $response = $generator($e, $request, ($this->responseFactory)());
         $this->triggerListeners($e, $request, $response);
         return $response;
     }