Merge pull request #308 from clue-labs/final-next

Do not pass $next handler to final request handler

Author: WyriHaximus

README.md

@@ -850,9 +850,13 @@ $server = new Server(array(
 ));
 ```
 
+> Note how the middleware request handler and the final request handler have a
+  very simple (and similar) interface. The only difference is that the final
+  request handler does not receive a `$next` handler.
+
 Similarly, you can use the result of the `$next` middleware request handler
 function to modify the outgoing response.
-Note that as per the above documentation, the `$next` method may return a
+Note that as per the above documentation, the `$next` function may return a
 `ResponseInterface` directly or one wrapped in a promise for deferred
 resolution.
 In order to simplify handling both paths, you can simply wrap this in a
@@ -1002,7 +1006,7 @@ Usage:
 $server = new StreamingServer(array(
     new LimitConcurrentRequestsMiddleware(100), // 100 concurrent buffering handlers
     new RequestBodyBufferMiddleware(16 * 1024 * 1024), // 16 MiB
-    function (ServerRequestInterface $request, callable $next) {
+    function (ServerRequestInterface $request) {
         // The body from $request->getBody() is now fully available without the need to stream it 
         return new Response(200);
     },

src/Io/MiddlewareRunner.php

@@ -29,7 +29,7 @@ public function __construct(array $middleware)
     /**
      * @param ServerRequestInterface $request
      * @return ResponseInterface|PromiseInterface<ResponseInterface>
-     * @throws Exception
+     * @throws \Exception
      */
     public function __invoke(ServerRequestInterface $request)
     {
@@ -43,11 +43,18 @@ public function __invoke(ServerRequestInterface $request)
     /** @internal */
     public function call(ServerRequestInterface $request, $position)
     {
+        // final request handler will be invoked without a next handler
+        if (!isset($this->middleware[$position + 1])) {
+            $handler = $this->middleware[$position];
+            return $handler($request);
+        }
+
         $that = $this;
         $next = function (ServerRequestInterface $request) use ($that, $position) {
             return $that->call($request, $position + 1);
         };
 
+        // invoke middleware request handler with next handler
         $handler = $this->middleware[$position];
         return $handler($request, $next);
     }

tests/Io/MiddlewareRunnerTest.php

@@ -31,6 +31,43 @@ public function testEmptyMiddlewareStackThrowsException()
         $middlewareStack($request);
     }
 
+    public function testMiddlewareHandlerReceivesTwoArguments()
+    {
+        $args = null;
+        $middleware = new MiddlewareRunner(array(
+            function (ServerRequestInterface $request, $next) use (&$args) {
+                $args = func_num_args();
+                return $next($request);
+            },
+            function (ServerRequestInterface $request) {
+                return null;
+            }
+        ));
+
+        $request = new ServerRequest('GET', 'http://example.com/');
+
+        $middleware($request);
+
+        $this->assertEquals(2, $args);
+    }
+
+    public function testFinalHandlerReceivesOneArgument()
+    {
+        $args = null;
+        $middleware = new MiddlewareRunner(array(
+            function (ServerRequestInterface $request) use (&$args) {
+                $args = func_num_args();
+                return null;
+            }
+        ));
+
+        $request = new ServerRequest('GET', 'http://example.com/');
+
+        $middleware($request);
+
+        $this->assertEquals(1, $args);
+    }
+
     /**
      * @expectedException RuntimeException
      * @expectedExceptionMessage hello
@@ -224,7 +261,7 @@ function (ServerRequestInterface $request, $next) use (&$receivedRequests) {
                 $receivedRequests[] = 'middleware2: ' . $request->getUri();
                 return $next($request);
             },
-            function (ServerRequestInterface $request, $next) use (&$receivedRequests) {
+            function (ServerRequestInterface $request) use (&$receivedRequests) {
                 $receivedRequests[] = 'middleware3: ' . $request->getUri();
                 return new \React\Promise\Promise(function () { });
             }