php curl从url获取文件内容，强制下载文件，返回错误“来自服务器的空回复”

Question

I am trying to load file content from URL which forces to download file with header Content-Type : application/octet-stream

The code which return error "Empty reply from server":

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, 'http://urltofile.com/file.csv');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

if(!$file = curl_exec($ch)) {

    echo curl_error($ch);

}

curl_close($ch);

echo $file;

Answer 1

I find the solution after few hours!

Sending custom headers and user agent with CURL solve this!

$ch = curl_init();

$agent="Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.3) Gecko/2008092417 Firefox/3.0.3";
$header=[];
$header[]="Accept: text/xml,text/csv,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5"; 
$header[]="Connection: keep-alive"; 
$header[]="Keep-Alive: 300"; 

curl_setopt($ch, CURLOPT_HTTPHEADER, $header); 
curl_setopt($ch, CURLOPT_URL, 'http://urltofile.com/file.csv');
curl_setopt($ch, CURLOPT_USERAGENT, $agent); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

if(!$file = curl_exec($ch)) {

    echo curl_error($ch);

}

curl_close($ch);

echo $file;

I hope that this will help someone! :)