## 創建core/PipleLine.php 中間件實現主要是靠 `PipeLine` ``` <?php namespace core; class PipeLine { // 所有要執行的類 protected $classes = []; // 類的方法名稱 protected $handleMethod = 'handle'; // 因為容器的單例的,所以要創建一個新的 對象 public function create() { return clone $this; } // 沒啥用 但是遵守原則而已 public function setHandleMethod($method) { $this->handleMethod = $method; return $this; } public function setClass($class) { $this->classes = $class; return $this; } // 傳遞閉包 運行管道 // 這個代碼過于抽象 學習文章: https://segmentfault.com/a/1190000017792800 public function run(\Closure $initial) { return array_reduce( array_reverse($this->classes),function($res, $currClass){ return function ($request) use ($res,$currClass) { return (new $currClass)->{$this->handleMethod}($request,$res); }; },$initial); } } ``` ## 代碼助你理解array_reduce ``` $datas = [ ['num' => 2, 'price' => 15], ['num' => 4, 'price' => 10], ]; ``` 現在要計算總價, `foreach`操作: ``` $sum = 0; foreach($datas as $data) $sum += $data['price'] * $data['num']; echo $sum; // 70 ``` 用 `array_reduce` ``` echo array_reduce($datas, function($sum = 0,$data){ return $sum += $data['num'] * $data['price']; }); // 70 ``` `array_reduce` 只是更簡潔的寫法而已,你大可用 `foreach` 來代替它。 (一般不會代替把,都喜歡簡潔) ## 綁定pipeline  ## 編輯RouteCollection.php 編輯 `dispatch` 方法 ``` // 根據request執行路由 public function dispatch(RequestInterface $request) { $method = $request->getMethod(); $uri = $request->getUri(); $this->route_index = $method . $uri; $route = $this->getCurrRoute(); if(! $route) return 404; $middleware = $route['action']['middleware'] ?? []; $routerDispatch = $route['action']['uses']; return \App::getContainer()->get('pipeline')->create()->setClass( $middleware )->run($routerDispatch)($request); } } ```  ## 創建app/middleware/WebMiddleWare.php ``` <?php namespace App\middleware; class WebMiddleWare { public function handle($request,\Closure $next) { echo "web middleware"; return $next($request); } } ``` ### 編輯routes/web.php   ### 在路由組添加中間件