Merge pull request #4 from jaapio/feature/middleware-locator

Adds middleware locator

Author: WyriHaximus

README.md

@@ -7,6 +7,49 @@
 [![License](https://poser.pugx.org/api-clients/middleware/license.png)](https://packagist.org/packages/api-clients/middleware)
 [![PHP 7 ready](http://php7ready.timesplinter.ch/php-api-clients/middleware/badge.svg)](https://appveyor-ci.org/php-api-clients/middleware)
 
+This library contains the a async `MiddlewareRunner` used in our api clients. It 
+provides an interface for all middlewares. Middlewares are ordered by priority
+when they where added to the `MiddlewareRunner`. Order of middlewares with the
+same priority is not guaranteed.
+
+A number of traits are provided for your convenience, if your middleware
+implementation does not require all the methods defined in the 
+`MiddlewareInterface`.
+
+## Locator
+The locator can be used by your application to fetch middleware instances.
+It will check whether the created instance implements the `MiddlewareInterface`.
+Currently the only provided locator is the `ContainerLocator` which accepts a
+`Interop\Container\ContainerInterface` to fetch your middleware instances.
+
+## Example
+```php
+    $container = /* ... */;
+    $locator = new ContainerLocator($container);
+    $middlewares = [];
+    
+    $config = [
+        'middlewares' => [/*...*/]
+        'options' => [/*...*/]
+    ];
+       
+    foreach ($config['middlewares'] as $middleware) {
+       $middlewares[] = $locator->get($middleware);
+    }
+    
+    $runner = new MiddlewareRunner($config['options'], $middelwares);
+    
+    $runner->pre($request)->then(function ($request) use ($options) {
+        return resolve($this->browser->send(
+            $request
+        ));
+    }, function (ResponseInterface $response) {
+        return resolve($response);
+    })->then(function (ResponseInterface $response) use ($runner) {
+        return $runner->post($response);
+    });
+```
+
 
 # License
 

composer.json

@@ -17,13 +17,15 @@
   },
   "require-dev": {
     "api-clients/test-utilities": "^1.0",
+    "container-interop/container-interop": "^1.1",
     "guzzlehttp/psr7": "^1.3"
   },
   "suggest": {
     "api-clients/middleware-cache": "Cache requests with different strategies",
     "api-clients/middleware-log": "Log requests and their context",
     "api-clients/middleware-oauth1": "Sign requests with oauth1",
-    "api-clients/middleware-pool": "Pool the maximum concurrent requests"
+    "api-clients/middleware-pool": "Pool the maximum concurrent requests",
+    "container-interop/container-interop": "Add a ContainerInterface implementation to use the ContainerLocator"
   },
   "autoload": {
     "psr-4": {