# 內容長度中間件 The Content Length Middleware will automatically append a`Content-Length`header to the response. This is to replace the`addContentLengthHeader`setting that was removed from Slim 3. This middleware should be placed on the center of the middleware stack so it gets executed last. > 內容長度中間件將自動向響應附加一個`Content-Length`標頭。這是為了取代`addContentLengthHeader`設置從Slim 3刪除。這個中間件應該放在中間件堆棧的中心，這樣它才會最后執行。 ## Usage ~~~php <?php use Slim\Factory\AppFactory; use Slim\Middleware\ContentLengthMiddleware; require __DIR__ . '/../vendor/autoload.php'; $app = AppFactory::create(); $contentLengthMiddleware = new ContentLengthMiddleware(); $app->add($contentLengthMiddleware); // ... $app->run(); ~~~