Merge pull request #3 from jakejohns/feature/json-decoder

Add JsonDecoder middleware

Author: Paul M. Jones

README.md

@@ -15,7 +15,7 @@ The _ResponseSender_ does nothing with the `$request` or `$response`, passing th
 
 The _ResponseSender_ is intended to go at the top of the Relay queue, so that it is the middleware with the last opportunity to do something with the returned response.
 
-To add the _ResponseSender_ to your Real queue, instantiate it directly ...
+To add the _ResponseSender_ to your Relay queue, instantiate it directly ...
 
 ```php
 $queue[] = new \Relay\Middleware\ResponseSender();
@@ -38,3 +38,32 @@ $queue = new \Relay\Middleware\ExceptionHandler(new ResponseImplementation());
 ```
 
 ... or use a `$resolver` of your choice to instantiate it from the `$queue`.
+
+## JsonDecoder
+
+Again, the _JsonDecoder_ does what it sounds like: it deserializes the JSON
+payload of a PSR-7 request object and makes the parameters available in
+subsequent middleware decorators.
+
+The _JsonDecoder_ checks the incoming request for a method other than `GET` and
+for an `application/json` `Content-Type` header. If it finds both of these, it
+decodes the JSON and makes it available as the _parsed body_ of the `$request`
+before passing it and the `$response` to `$next`. If the method is `GET` or the
+`Content-Type` header does not specify `application/json`, the _JsonDecoder_
+does nothing with the `$request` and passes it and the `$response` to `$next`.
+
+
+To add the _JsonDecoder_ to your queue, instantiate it directly...
+
+```php
+$queue = new \Relay\Middleware\JsonDecoder();
+```
+
+... or use a `$resolver` of your choice to instantiate it from the `$queue`.
+
+To access the decoded parameters in subsequent middleware, use the
+`getParsedBody()` method of the `$request`
+
+```php
+$decodedJsonData = $request->getParsedBody();
+```

src/JsonDecoder.php

@@ -0,0 +1,24 @@
+<?php
+namespace Relay\Middleware;
+
+use Psr\Http\Message\ResponseInterface as Response;
+use Psr\Http\Message\ServerRequestInterface as Request;
+
+class JsonDecoder
+{
+    public function __invoke(Request $request, Response $response, callable $next)
+    {
+        $type   = $request->getHeader('Content-Type');
+        $method = $request->getMethod();
+
+        if ('GET' != $method
+            && ! empty($type)
+            && 'application/json' == strtolower($type[0])
+        ) {
+            $body    = (string) $request->getBody();
+            $request = $request->withParsedBody(json_decode($body));
+        }
+
+        return $next($request, $response);
+    }
+}

tests/JsonDecoderTest.php

@@ -0,0 +1,62 @@
+<?php
+namespace Relay\Middleware;
+
+use Zend\Diactoros\Response;
+use Zend\Diactoros\ServerRequestFactory;
+use Zend\Diactoros\Stream;
+
+
+class JsonDecoderTest extends \PHPUnit_Framework_TestCase
+{
+
+    protected $data = ['foo', 'bar'];
+
+
+    public function requestProvider()
+    {
+        return [
+            ['GET'   , 'application/json', []],
+            ['GET'   , null, []],
+            ['POST'  , 'application/json', $this->data],
+            ['POST'  , null, []],
+            ['PUT'   , 'application/json', $this->data],
+            ['PUT'   , null, []],
+            ['PATCH' , 'application/json', $this->data],
+            ['PATCH' , null, []],
+            ['other' , 'application/json', $this->data],
+            ['other' , null, []]
+        ];
+    }
+
+    /**
+     * @dataProvider requestProvider
+     */
+    public function testParser($method, $contentType, $expected)
+    {
+        $json = json_encode($this->data);
+
+        $stream = new Stream('php://temp', 'wb+');
+        $stream->write($json);
+
+        $jsonDecoder = new JsonDecoder();
+
+        $response = new Response();
+        $request = ServerRequestFactory::fromGlobals()
+            ->withMethod($method)
+            ->withBody($stream);
+
+        if ($contentType) {
+            $request = $request->withHeader('Content-Type', $contentType);
+        }
+
+        $parsedRequest = $jsonDecoder(
+            $request,
+            $response,
+            function ($request, $response) {
+                return $request;
+            }
+        );
+
+        $this->assertEquals($expected, $parsedRequest->getParsedBody());
+    }
+}