Make middleware pass the response attributes to formatter

src/ContentTypeMiddleware.php

@@ -107,7 +107,7 @@ private function formatResponse(UnformattedResponse $response, ?Formatter $forma
             return $response->withStatus(StatusCodeInterface::STATUS_NOT_ACCEPTABLE);
         }
 
-        $body->write($formatter->format($response->getUnformattedContent()));
+        $body->write($formatter->format($response->getUnformattedContent(), $response->getAttributes()));
         $body->rewind();
 
         return $response;

tests/ContentTypeMiddlewareTest.php

@@ -13,10 +13,17 @@
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Psr\Http\Server\RequestHandlerInterface;
+use SplFileObject;
 use Zend\Diactoros\Response;
 use Zend\Diactoros\Response\EmptyResponse;
 use Zend\Diactoros\ServerRequest;
+use function array_keys;
+use function array_map;
+use function assert;
 use function ini_set;
+use function is_string;
+use function str_replace;
+use function trim;
 
 /**
  * @coversDefaultClass \Lcobucci\ContentNegotiation\ContentTypeMiddleware
@@ -99,6 +106,50 @@ public function processShouldReturnAResponseWithFormattedContent(): void
         self::assertJsonStringEqualsJsonString('{"id":1,"name":"Testing"}', (string) $response->getBody());
     }
 
+    /**
+     * @test
+     *
+     * @covers ::__construct()
+     * @covers ::fromRecommendedSettings()
+     * @covers ::process()
+     * @covers ::extractContentType()
+     * @covers ::formatResponse()
+     *
+     * @uses \Lcobucci\ContentNegotiation\UnformattedResponse
+     * @uses \Lcobucci\ContentNegotiation\Formatter\Json
+     */
+    public function processShouldPassAttributesToTheFormatterProperly(): void
+    {
+        $middleware = $this->createMiddleware();
+
+        $response = $middleware->process(
+            (new ServerRequest())->withAddedHeader('Accept', 'text/html'),
+            $this->createRequestHandler(
+                new UnformattedResponse(
+                    new Response(),
+                    new PersonDto(1, 'Testing'),
+                    ['template' => 'person']
+                )
+            )
+        );
+
+        $formattedContent = <<<'TEMPLATE'
+<section>
+    <dl>
+        <dt>Identifier</dt>
+        <dd>1</dd>
+        <dt>Name</dt>
+        <dd>Testing</dd>
+    </dl>
+</section>
+TEMPLATE;
+
+        self::assertInstanceOf(UnformattedResponse::class, $response);
+        self::assertSame(StatusCodeInterface::STATUS_OK, $response->getStatusCode());
+        self::assertSame('text/html; charset=UTF-8', $response->getHeaderLine('Content-Type'));
+        self::assertSame($formattedContent, (string) $response->getBody());
+    }
+
     /**
      * @test
      *
@@ -223,9 +274,47 @@ private function createMiddleware(bool $forceCharset = true, ?callable $streamFa
                     'mime-type' => ['text/plain'],
                     'charset' => $forceCharset,
                 ],
+                'html' => [
+                    'extension' => ['html', 'htm'],
+                    'mime-type' => ['text/html', 'application/xhtml+xml'],
+                    'charset'   => $forceCharset,
+                ],
+            ],
+            [
+                'application/json' => new Formatter\Json(),
+                'text/html'        => $this->createNaiveTemplatingEngine(),
             ],
-            ['application/json' => new Formatter\Json()],
             $streamFactory
         );
     }
+
+    private function createNaiveTemplatingEngine(): Formatter
+    {
+        return new class implements Formatter
+        {
+            /**
+             * {@inheritdoc}
+             */
+            public function format($content, array $attributes = []): string
+            {
+                $template = $attributes['template'] ?? '';
+                assert(is_string($template));
+
+                $file = new SplFileObject(
+                    __DIR__ . '/templates/naive/' . $template . '.html'
+                );
+
+                $data = (array) $content;
+
+                $variables = array_map(
+                    function (string $attribute): string {
+                        return '{' . $attribute . '}';
+                    },
+                    array_keys($data)
+                );
+
+                return trim(str_replace($variables, $data, $file->fread($file->getSize())));
+            }
+        };
+    }
 }

tests/templates/naive/person.html

@@ -0,0 +1,8 @@
+<section>
+    <dl>
+        <dt>Identifier</dt>
+        <dd>{id}</dd>
+        <dt>Name</dt>
+        <dd>{name}</dd>
+    </dl>
+</section>