我如何卷曲范围和用户代理

GET /folder/downloads/xx.zip HTTP/1.1
Range: bytes=0-6423263
User-Agent: Dalvik
Host: xx.xx.xxx.xxx:2050
Connection: Keep-Alive
Accept-Encoding: gzip

need to this in curl am try but is not work can give me true code i try

    $data = array('Range'=>"0-6423263");
curl_setopt($curl, CURLOPT_URL, "http://xx.xx.xxx.xxx:2050/folder/downloads/xx.zip");
curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($data));
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($curl, CURLOPT_VERBOSE, 1);
curl_setopt($curl, CURLOPT_POST, 0);
curl_setopt($curl, CURLOPT_HTTPGET, 1);
curl_setopt($curl, CURLOPT_USERAGENT, 'Dalvik');
$output = curl_exec($curl);

CURLOPT_POSTFIELDS specify data to POST to server. Check CURLOPT_RANGE instead.

curl_setopt($curl, CURLOPT_RANGE, '0-6423263');

By default curl use keep-alive by himself. You don't need to declare it.

For Accept-Encoding header, use CURLOPT_ENCODING

curl_setopt($curl, CURLOPT_ENCODING, 'gzip');