Merge branch 'feature/content-length-middleware' into develop

Close #45

CHANGELOG.md

@@ -2,11 +2,14 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
-## 4.1.0 - TBD
+## 4.1.0 - 2017-09-11
 
 ### Added
 
-- Nothing.
+- [#45](https://github.com/zendframework/zend-expressive-helpers/pull/45) adds
+  `Zend\Expressive\Helper\ContentLengthMiddleware`. This middleware will inject
+  a `Content-Length` response header if none already exists and the response
+  body size is non-null.
 
 ### Deprecated
 

README.md

@@ -541,7 +541,63 @@ Note: if you do this, **all** strategies will be removed! As such, we recommend
 doing this only immediately before registering any custom strategies you might
 be using.
 
+### Content-Length middleware
+
+In some cases, you may want to include an explicit `Content-Length` response
+header, without having to inject it manually. To facilitate this, we provide
+`Zend\Expressive\Helper\ContentLengthMiddleware`.
+
+This middleware delegates the request, and operates on the returned response. It
+will return a new response with the `Content-Length` header injected under the
+following conditions:
+
+- No `Content-Length` header is already present AND
+- the body size is non-null.
+
+To register it in your application, you will need to do two things: register the
+middleware with the container, and register the middleware in either your
+application pipeline, or within routed middleware.
+
+To add it to your container, add the following configuration:
+
+```php
+// In a `config/autoload/*.global.php` file, or a `ConfigProvider` class:
+
+use Zend\Expressive\Helper;
+
+return [
+    'dependencies' => [
+        'invokables' => [
+            Helper\ContentLengthMiddleware::class => Helper\ContentLengthMiddleware::class,
+        ],
+    ],
+];
+```
+
+To register it as pipeline middleware to execute on any request:
+
+```php
+// In `config/pipeline.php`:
+
+use Zend\Expressive\Helper;
+
+$app->pipe(Helper\ContentLengthMiddleware::class);
+```
+
+To register it within a routed middleware pipeline:
+
+```php
+// In `config/routes.php`:
+
+use Zend\Expressive\Helper;
+
+$app->get('/download/tarball', [
+    Helper\ContentLengthMiddleware::class,
+    Download\Tarball::class,
+], 'download-tar');
+```
+
 ## Documentation
 
 See the [zend-expressive](https://github.com/zendframework/zend-expressive/blob/master/doc/book)
-documentation tree, or browse online at http://zend-expressive.rtfd.org.
+documentation tree, or browse online at https://docs.zendframework.com/zend-expressive/features/helpers/intro/

src/ContentLengthMiddleware.php

@@ -0,0 +1,40 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-expressive-helpers for the canonical source repository
+ * @copyright Copyright (c) 2017 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   https://github.com/zendframework/zend-expressive-helpers/blob/master/LICENSE.md New BSD License
+ */
+
+namespace Zend\Expressive\Helper;
+
+use Interop\Http\ServerMiddleware\DelegateInterface;
+use Interop\Http\ServerMiddleware\MiddlewareInterface;
+use Psr\Http\Message\ServerRequestInterface;
+
+/**
+ * Middleware to inject a Content-Length response header.
+ *
+ * If the response returned by a delegate does not contain a Content-Length
+ * header, and the body size is non-null, this middleware will return a new
+ * response that contains a Content-Length header based on the body size.
+ */
+class ContentLengthMiddleware implements MiddlewareInterface
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function process(ServerRequestInterface $request, DelegateInterface $delegate)
+    {
+        $response = $delegate->process($request);
+        if ($response->hasHeader('Content-Length')) {
+            return $response;
+        }
+
+        $body = $response->getBody();
+        if (null === $body->getSize()) {
+            return $response;
+        }
+
+        return $response->withHeader('Content-Length', (string) $body->getSize());
+    }
+}

test/ContentLengthMiddlewareTest.php

@@ -0,0 +1,59 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-expressive-helpers for the canonical source repository
+ * @copyright Copyright (c) 2017 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   https://github.com/zendframework/zend-expressive-helpers/blob/master/LICENSE.md New BSD License
+ */
+
+namespace ZendTest\Expressive\Helper;
+
+use Interop\Http\ServerMiddleware\DelegateInterface;
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Message\StreamInterface;
+use Zend\Expressive\Helper\ContentLengthMiddleware;
+
+class ContentLengthMiddlewareTest extends TestCase
+{
+    public function setUp()
+    {
+        $this->response = $response = $this->prophesize(ResponseInterface::class);
+        $this->request = $request = $this->prophesize(ServerRequestInterface::class)->reveal();
+        $this->stream = $this->prophesize(StreamInterface::class);
+
+        $delegate = $this->prophesize(DelegateInterface::class);
+        $delegate->process($request)->will([$response, 'reveal']);
+        $this->delegate = $delegate->reveal();
+
+        $this->middleware = new ContentLengthMiddleware();
+    }
+
+    public function testReturnsResponseVerbatimIfContentLengthHeaderPresent()
+    {
+        $this->response->hasHeader('Content-Length')->willReturn(true);
+        $response = $this->middleware->process($this->request, $this->delegate);
+        $this->assertSame($this->response->reveal(), $response);
+    }
+
+    public function testReturnsResponseVerbatimIfContentLengthHeaderNotPresentAndBodySizeIsNull()
+    {
+        $this->stream->getSize()->willReturn(null);
+        $this->response->hasHeader('Content-Length')->willReturn(false);
+        $this->response->getBody()->will([$this->stream, 'reveal']);
+
+        $response = $this->middleware->process($this->request, $this->delegate);
+        $this->assertSame($this->response->reveal(), $response);
+    }
+
+    public function testReturnsResponseWithContentLengthHeaderBasedOnBodySize()
+    {
+        $this->stream->getSize()->willReturn(42);
+        $this->response->hasHeader('Content-Length')->willReturn(false);
+        $this->response->getBody()->will([$this->stream, 'reveal']);
+        $this->response->withHeader('Content-Length', '42')->will([$this->response, 'reveal']);
+
+        $response = $this->middleware->process($this->request, $this->delegate);
+        $this->assertSame($this->response->reveal(), $response);
+    }
+}