Chrome saving streamed file as .gz
I have been banging my head against the wall with this odd behaviour on Chrome
I have files stored encrypted on disk in an unnamed, unordered state. when the files are downloaded by the user, the client is redirected to a download handlers (.ashx) the data is loaded into a stream, decrypted and sent to the client. Now this has worked fine until recently,
It works fine on all browsers except chrome where the file is downloaded as a .gz file and is unreadable?
I have stripped out the stream fetching and cryptography parts for brevity (keep in mind this works perfectly on IE, Firefox etc)
Private Function StreamFile(ByVal context As System.Web.HttpContext) As Boolean
context.Response.Clear()
context.Response.ClearHeaders()
context.Response.BufferOutput = False
context.Response.ContentType = "application/octet-stream"
context.Response.AddHeader("content-disposition", "attachment;filename=""" & _sFileName & """")
context.Response.AddHeader("content-length", _iSize)
context.Response.Cache.SetNoServerCaching()
context.Response.Cache.SetMaxAge(System.TimeSpan.Zero)
Dim oInputStream As System.IO.Stream = GetStream()
Dim oBufferedStream As New BufferedStream(oFileStream, context.Response.OutputStream)
oBufferedStream.ProcessStreams(True)
context.ApplicationInstance.CompleteRequest()
Return True
End Function
Public Class BufferedStream
Private _oInputStream As Stream
Private _oOutputStream As Stream
Private _bBuffer() As Byte
Public Const DEFAULT_BUFFER_SIZE As Integer = 8192
Public Sub New(ByRef oInputStream As Stream, ByRef oOutputStream As Stream)
_oInputStream = oInputStream
_oOutputStream = oOutputStream
_bBuffer = GetStreamBuffer(ToInteger(_oInputStream.Length))
End Sub
Public Function ProcessStreams(ByVal bCloseStreams As Boolean) As Boolean
Dim iRead As Integer = 0
Dim iStreamLength As Integer = ToInteger(_oInputStream.Length)
Try
iRead = _oInputStream.Read(_bBuffer, 0, _bBuffer.Length)
While iRead > 0
_oOutputStream.Write(_bBuffer, 0, _bBuffer.Length)
iRead = _oInputStream.Read(_bBuffer, 0, _bBuffer.Length)
If iRead < _bBuffer.Length Then System.Array.Resize(_bBuffer, iRead)
End While
If bCloseStreams Then
Close()
End If
Return True
Catch
Return False
End Try
End Function
Public Shared Function GetStreamBuffer(ByVal iStreamSize As Integer) As Byte()
Dim iBufferSize As Integer = iStreamSize - 1
开发者_如何学CIf iBufferSize > DEFAULT_BUFFER_SIZE Then iBufferSize = DEFAULT_BUFFER_SIZE
Dim bBuffer As Byte() = New Byte(iBufferSize) {}
Return bBuffer
End Function
End Class
Any help would be greatly appreciated.
Here is the HTTP header from fiddler when the file is downloaded in chrome
HTTP/1.1 200 OK
Date: Fri, 30 Oct 2009 00:01:45 GMT
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
X-AspNet-Version: 2.0.50727
content-disposition: attachment;filename="codeKiwi.txt"
Content-Length: 349
Cache-Control: private, max-age=0
Content-Type: application/octet-stream
Note that the filename is codekiwi.txt and the contents are some simple plain text, the file gets saved as codekiwi.txt.gz and contains gibberish.
Ok, solved it myself. I turns out that Chrome (and Firefox) REALLY don't like the response.ClearHeaders call, for some reason IE was ok with this, once I removed it the downloads functioned as expected again...
精彩评论