Get original filename when downloading with WebClient
If you, like me, have to deal with a Content-Disposition header that is not formatted correctly or cannot be parsed automatically by the ContentDisposition class for some reason, here's my solution :
string fileName = null;
// Getting file name
var request = WebRequest.Create(url);
request.Method = "HEAD";
using (var response = request.GetResponse())
{
// Headers are not correct... So we need to parse manually
var contentDisposition = response.Headers["Content-Disposition"];
// We delete everything up to and including 'Filename="'
var fileNameMarker= "filename=\"";
var beginIndex = contentDisposition.ToLower().IndexOf(fileNameMarker);
contentDisposition = contentDisposition.Substring(beginIndex + fileNameMarker.Length);
//We only get the string until the next double quote
var fileNameLength = contentDisposition.ToLower().IndexOf("\"");
fileName = contentDisposition.Substring(0, fileNameLength);
}
Read the Response Header "Content-Disposition"
with WebClient.ResponseHeaders
It should be:
Content-Disposition: attachment; filename="fname.ext"
your code should look like:
string header = wc.ResponseHeaders["Content-Disposition"]??string.Empty;
const string filename="filename=";
int index = header.LastIndexOf(filename,StringComparison.OrdinalIgnoreCase);
if (index > -1)
{
fileName = header.Substring(index+filename.Length);
}
To get the filename without downloading the file:
public string GetFilenameFromWebServer(string url)
{
string result = "";
var req = System.Net.WebRequest.Create(url);
req.Method = "HEAD";
using (System.Net.WebResponse resp = req.GetResponse())
{
// Try to extract the filename from the Content-Disposition header
if (!string.IsNullOrEmpty(resp.Headers["Content-Disposition"]))
{
result = resp.Headers["Content-Disposition"].Substring(resp.Headers["Content-Disposition"].IndexOf("filename=") + 9).Replace("\"", "");
}
}
return result;
}
You need to examine the response headers and see if there is a content-disposition header present which includes the actual filename.
WebClient wc = new WebClient();
var data= wc.DownloadData(@"www.sometime.com\getfile?id=123");
string fileName = "";
// Try to extract the filename from the Content-Disposition header
if (!String.IsNullOrEmpty(wc.ResponseHeaders["Content-Disposition"]))
{
fileName = wc.ResponseHeaders["Content-Disposition"].Substring(wc.ResponseHeaders["Content-Disposition"].IndexOf("filename=") + 9).Replace("\"", "");
}