public static void DownloadFile(HttpContext context, string filepath, string filename, bool isPublic)
{
if (context == null)
{
throw (new ArgumentNullException("context"));
}
if (filepath == null)
{
throw (new ArgumentNullException("filepath"));
}
if (filename == null)
{
throw (new ArgumentNullException("filename"));
}
if (!File.Exists(filepath))
{
throw (new HttpException(404, filename + " not found!"));
}
FileInfo fileinfo = new FileInfo(filepath);
int filesize = (int)fileinfo.Length;
int start, length;
bool hasRange = GetRange(context, filesize, out start, out length);
if (!hasRange)
{
string since = context.Request.Headers["If-Modified-Since"];
if (!string.IsNullOrEmpty(since))
{
DateTime sinceDate = DateTime.Parse(since);
TimeSpan sinceSpan = fileinfo.LastWriteTime - sinceDate;
if (sinceSpan.TotalSeconds < 1 && sinceSpan.TotalSeconds > -1)
{
context.Response.Status = "304 (Not Modified)";
context.Response.End();
return;
}
}
}
if (isPublic)
{
context.Response.Cache.SetCacheability(HttpCacheability.Private);
context.Response.Cache.SetETag(CalcETag(fileinfo.FullName + ":" + fileinfo.LastWriteTime.Ticks));
context.Response.Cache.SetLastModified(fileinfo.LastWriteTime);
}
else
{
//maybe the attachment is security file . do not cache it!
context.Response.Cache.SetCacheability(HttpCacheability.NoCache);
}
string attachemntame = filename;
string mime = SampleUtil.GetMimeType(filename);
context.Response.ContentType = mime;
if (mime.StartsWith("text/"))
{
//all text file can be html or script.
//it's dangerous that let the user open the html file on the browser directly.
//the html may contains javascript that can thieve the cookie of the user on your website.
//change the response and force the browser download the file.
context.Response.ContentType = "application/unknown";
attachemntame = attachemntame + ".download";
}
//attachemntame = context.Server.UrlEncode(attachemntame);
context.Response.AddHeader("Content-Disposition", "inline;filename=" + attachemntame);
byte[] buff = new byte[0x10000];
Stream outp = context.Response.OutputStream;
using (FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
if (hasRange)
{
context.Response.StatusCode = 206;
context.Response.AddHeader("Content-Length", length.ToString());
context.Response.AddHeader("Content-Range", "bytes " + start + "-" + (start + length - 1) + "/" + filesize);
}
else
{
context.Response.AddHeader("Content-Length", filesize.ToString());
start = 0;
length = filesize;
}
if (start != 0)
{
fs.Seek(start, SeekOrigin.Begin);
}
int readlen = 0;
while (true)
{
int readnow = Math.Min(0x10000, length - readlen);
if (readnow <= 0)
{
break;
}
int rc = fs.Read(buff, 0, readnow);
if (rc <= 0)
{
break;
}
readlen += rc;
if (CuteWebUI.UploadModule.LimitSpeedForTest)
{
System.Threading.Thread.Sleep(100);
}
outp.Write(buff, 0, rc);
//if the client is disconnect , this method will throw an exception and stop sending file data
context.Response.Flush();
}
}
}