如何使用PHP从s3下载私有文件？

Question

I have saved a file in amazon s3 bucked as a private file now I want to download this file. I am using amazon s3 PHP component

my download function is as below but I am getting exception [403] Unexpected HTTP status

function downloadPrivateFile($bucket, $fileUrl) {
        $obj = new S3($this->keyId, $this->secretKey);
        echo $obj->getObjectInfo($bucket, $fileUrl);
    }

Can anyone please help me how to download a private file.