Update Dispatcher

src/Routing/Dispatcher.php

@@ -11,16 +11,22 @@ class Dispatcher implements DispatcherInterface
      * @param $middleware
      * @param ServerRequestInterface $request
      * @param ResponseInterface $response
+     * @return ResponseInterface
+     * @throws \InvalidArgumentException $middleware is not a valid type.
      */
-    public function dispatch($middleware, ServerRequestInterface $request, ResponseInterface &$response)
+    public function dispatch($middleware, ServerRequestInterface $request, ResponseInterface $response, $next)
     {
         if (is_callable($middleware)) {
-            $middleware = $middleware($request, $response);
+            $middleware = $middleware($request, $response, $next);
         } elseif (is_string($middleware)) {
             $middleware = new $middleware();
         }
         if ($middleware instanceof MiddlewareInterface) {
-            $middleware->dispatch($request, $response);
+            return $middleware->dispatch($request, $response, $next);
+        } elseif ($middleware instanceof ResponseInterface) {
+            return $middleware;
+        } else {
+            throw new \InvalidArgumentException("Unable to dispatch middleware.");
         }
     }
 }

src/Routing/DispatcherInterface.php

@@ -16,6 +16,8 @@ interface DispatcherInterface
      * @param $middleware
      * @param ServerRequestInterface $request
      * @param ResponseInterface $response
+     * @param callable $next
+     * @return ResponseInterface
      */
-    public function dispatch($middleware, ServerRequestInterface $request, ResponseInterface &$response);
+    public function dispatch($middleware, ServerRequestInterface $request, ResponseInterface $response, $next);
 }

test/tests/unit/Routing/DispatcherTest.php

@@ -15,30 +15,31 @@ class DispatcherTest extends \PHPUnit_Framework_TestCase
 {
     private $request;
     private $response;
+    private $next;
 
     public function setUp()
     {
-        $this->request = $this->prophesize("\\Psr\\Http\\Message\\ServerRequestInterface");
-        $this->response = $this->prophesize("\\Psr\\Http\\Message\\ResponseInterface");
+        $this->request = $this->prophesize('Psr\Http\Message\ServerRequestInterface');
+        $this->response = $this->prophesize('Psr\Http\Message\ResponseInterface');
         $this->response->withStatus(Argument::any())->will(
             function ($args) {
                 $this->getStatusCode()->willReturn($args[0]);
                 return $this;
             }
         );
+        $this->next = function ($request, $response) {
+            return $response;
+        };
     }
 
-    public function testDispatchesCallable()
+    public function testDispatchesCallableThatReturnsResponse()
     {
-        $middleware = function ($request, &$response) {
-            $response = $response->withStatus(200);
+        $middleware = function ($request, $response, $next) {
+            return $next($request, $response->withStatus(200));
         };
 
         $dispatcher = new Dispatcher();
-        $request = $this->request->reveal();
-        $response = $this->response->reveal();
-        $dispatcher->dispatch($middleware, $request, $response);
-
+        $response = $dispatcher->dispatch($middleware, $this->request->reveal(), $this->response->reveal(), $this->next);
         $this->assertEquals(200, $response->getStatusCode());
     }
 
@@ -49,22 +50,16 @@ class DispatcherTest extends \PHPUnit_Framework_TestCase
         };
 
         $dispatcher = new Dispatcher();
-        $request = $this->request->reveal();
-        $response = $this->response->reveal();
-        $dispatcher->dispatch($middleware, $request, $response);
-
+        $response = $dispatcher->dispatch($middleware, $this->request->reveal(), $this->response->reveal(), $this->next);
         $this->assertEquals(200, $response->getStatusCode());
     }
 
     public function testDispatchesMiddlewareFromClassNameString()
     {
-        $middleware = __NAMESPACE__ . "\\DispatcherTest_Middleware";
+        $middleware = __NAMESPACE__ . '\DispatcherTest_Middleware';
 
         $dispatcher = new Dispatcher();
-        $request = $this->request->reveal();
-        $response = $this->response->reveal();
-        $dispatcher->dispatch($middleware, $request, $response);
-
+        $response = $dispatcher->dispatch($middleware, $this->request->reveal(), $this->response->reveal(), $this->next);
         $this->assertEquals(200, $response->getStatusCode());
     }
 
@@ -73,18 +68,27 @@ class DispatcherTest extends \PHPUnit_Framework_TestCase
         $middleware = new DispatcherTest_Middleware();
 
         $dispatcher = new Dispatcher();
-        $request = $this->request->reveal();
-        $response = $this->response->reveal();
-        $dispatcher->dispatch($middleware, $request, $response);
-
+        $response = $dispatcher->dispatch($middleware, $this->request->reveal(), $this->response->reveal(), $this->next);
         $this->assertEquals(200, $response->getStatusCode());
     }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     */
+    public function testThrowExceptionWhenUnableToDispatch()
+    {
+        $middleware = null;
+
+        $dispatcher = new Dispatcher();
+        $dispatcher->dispatch($middleware, $this->request->reveal(), $this->response->reveal(), $this->next);
+    }
 }
 
 class DispatcherTest_Middleware implements MiddlewareInterface
 {
-    public function dispatch(ServerRequestInterface $request, ResponseInterface &$response)
+    public function dispatch(ServerRequestInterface $request, ResponseInterface $response, $next)
     {
         $response = $response->withStatus(200);
+        return $next($request, $response);
     }
 }