private void DoPartialRead(string cleanUrl, URLRequestBase request,
ResourceResponse response)
{
string rangeValue = request.GetExtraHeader("Range");
Match match = m_RangeRequestValue.Match (rangeValue);
if (!match.Success)
{
response.SignalFailure();
return;
}
long fileSize = new FileInfo(cleanUrl).Length;
long startByte = long.Parse (match.Groups ["From"].Value);
string endByteString = match.Groups ["To"].Value;
long endByte = fileSize - 1;
if (string.IsNullOrEmpty(endByteString))
{
// Clamp to a maximum chunk size
const long MaxPartialReadSize = 16 * 1024 * 1024;
if (endByte - startByte > MaxPartialReadSize)
{
endByte = startByte + MaxPartialReadSize;
}
}
else
{
endByte = long.Parse(endByteString);
}
// Clamp to int.MaxValue since that's the type BinaryReader
// allows us to read; if it could read more bytes, then we would
// clamp the size to uint.MaxValue since ResourceResponse.GetBuffer
// expects an uint value.
long bufferSize = Math.Min((long)int.MaxValue,
endByte - startByte + 1);
byte[] bytes = new byte[bufferSize];
using (BinaryReader reader = new BinaryReader(
new FileStream(cleanUrl, FileMode.Open)))
{
reader.BaseStream.Seek(startByte, SeekOrigin.Begin);
reader.Read(bytes, 0, (int)bufferSize);
}
IntPtr buffer = response.GetBuffer((uint)bytes.Length);
if (buffer == IntPtr.Zero)
{
response.SignalFailure();
return;
}
Marshal.Copy(bytes, 0, buffer, bytes.Length);
// Set required response headers
response.SetStatus(206);
response.SetResponseHeader("Accept-Ranges", "bytes");
response.SetResponseHeader("Content-Range", "bytes " + startByte +
"-" + endByte + "/" + fileSize);
response.SetResponseHeader("Content-Length",
bufferSize.ToString());
response.SignalSuccess();
}