remote URL: http://cloudcallcenter-online.oss-cn-shanghai.aliyuncs.com/record/cc278f9c-104c-44d3-ac3a-0d5a85f127b6/152626432510500080329349.wav?Expires=1527220202&OSSAccessKeyId=LTAIvKWEr4DoFSqz&Signature=T2dBY2elShoYunkp4fKY1d3PC3U%3D
Code: `public function download ($url, $dir)
{
$ch = curl_init($url);
$fp = fopen($dir, "wb");
curl_setopt($ch, CURLOPT_FILE, $fp);
curl_setopt($ch, CURLOPT_HEADER, 0);
$res = curl_exec($ch);
curl_close($ch);
fclose($fp);
}`
.