使用CakePHP 2.X下载.txt文件

Question

I'm trying to download a .txt file using CakePHP. The .txt file contains

0 6652,20
0003,24

In my controller I use this :

$this->response->file($myFile->path, array('download' => true));
return $this->response;

But when I check the file downloaded, I just have this :

0 6652,

When I check the file directly by FTP I can see the file is complete, but when I download it with CakePHP it's not complete ... where's my mistake ?

Thanks