AttributeMapper middleware

README.md

@@ -123,6 +123,7 @@ $response = $dispatcher(ServerRequestFactory::fromGlobals(), new Response());
 ## Available middlewares
 
 * [AccessLog](#accesslog)
+* [AttributeMapper](#attributemapper)
 * [AuraRouter](#aurarouter)
 * [AuraSession](#aurasession)
 * [BasePath](#basepath)
@@ -193,6 +194,36 @@ $dispatcher = $relay->getInstance([
 ]);
 ```
 
+
+### AttributeMapper
+
+Maps middleware specific attribute to regural request attribute under desired name:
+
+```php
+use Psr7Middlewares\Middleware;
+
+$dispatcher = $relay->getInstance([
+
+    Middleware::BasicAuthentication([
+            'username1' => 'password1',
+            'username2' => 'password2'
+        ])
+        ->realm('My realm'), //(optional) change the realm value
+
+    Middleware::attributeMapper([
+        Middleware\BasicAuthentication::KEY => 'auth:username'
+    ]),
+
+    function ($request, $response, $next) {
+        $username = BasicAuthentication::getUsername($request);
+
+        assert($username === $request->getAttribute('auth:username'));
+
+        return $next($request, $response);
+    }
+]);
+```
+
 ### AuraRouter
 
 To use [Aura.Router (3.x)](https://github.com/auraphp/Aura.Router) as a middleware:
@@ -294,7 +325,13 @@ $dispatcher = $relay->getInstance([
             'username1' => 'password1',
             'username2' => 'password2'
         ])
-        ->realm('My realm') //(optional) change the realm value
+        ->realm('My realm'), //(optional) change the realm value
+
+    function ($request, $response, $next) {
+        $username = BasicAuthentication::getUsername($request);
+
+        return $next($request, $response);
+    }
 ]);
 ```
 
@@ -510,7 +547,13 @@ $dispatcher = $relay->getInstance([
             'username2' => 'password2'
         ])
         ->realm('My realm') //(optional) custom realm value
-        ->nonce(uniqid())   //(optional) custom nonce value
+        ->nonce(uniqid()),   //(optional) custom nonce value
+
+    function ($request, $response, $next) {
+        $username = DigestAuthentication::getUsername($request);
+
+        return $next($request, $response);
+    }
 ]);
 ```
 

src/Middleware/AttributeMapper.php

@@ -0,0 +1,57 @@
+<?php
+namespace Psr7Middlewares\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr7Middlewares\Middleware;
+
+/**
+ * Provides ability to route Psr7Middlewares specific attributes into scalar attributes.
+ *
+ * @todo Raise an exception if no attribute found?
+ */
+class AttributeMapper
+{
+    /**
+     * @var array
+     */
+    private $mapping = [];
+
+    /**
+     * Example:
+     *
+     * [
+     *      BasicAuthentication::KEY => 'basic.username'
+     * ]
+     *
+     * @param array $mapping
+     */
+    public function __construct(array $mapping)
+    {
+        $this->mapping = $mapping;
+    }
+
+    /**
+     * Execute the middleware.
+     *
+     * @param ServerRequestInterface $request
+     * @param ResponseInterface      $response
+     * @param callable               $next
+     *
+     * @return ResponseInterface
+     */
+    public function __invoke(
+        ServerRequestInterface $request,
+        ResponseInterface $response,
+        callable $next
+    ) {
+        foreach ($this->mapping as $middleware => $attribute) {
+            $request = $request->withAttribute(
+                $attribute,
+                Middleware::getAttribute($request, $middleware)
+            );
+        }
+
+        return $next($request, $response);
+    }
+}

tests/AttributeMapperTest.php

@@ -0,0 +1,36 @@
+<?php
+use Psr7Middlewares\Middleware;
+
+class AttributeMapperTest extends Base
+{
+    public function testUsernameMiddlewareRouting()
+    {
+        $response = $this->execute(
+            [
+                Middleware::BasicAuthentication(['username' => 'password'])->realm('My realm'),
+
+                Middleware::attributeMapper([
+                    Middleware\BasicAuthentication::KEY => 'auth:username'
+                ]),
+
+                function ($request, $response, $next) {
+                    $response->getBody()->write($request->getAttribute('auth:username'));
+
+                    return $response;
+                }
+            ],
+            '',
+            [
+                'Authorization' => $this->authHeader('username', 'password')
+            ]
+        );
+
+        $this->assertSame(200, $response->getStatusCode());
+        $this->assertSame('username', (string)$response->getBody());
+    }
+
+    private function authHeader($username, $password)
+    {
+        return 'Basic ' . base64_encode("{$username}:{$password}");
+    }
+}