User cancels file download and aspnet_wp.exe recycles

[Fade]

Hi all,

 

I have an ASP.net website that uses an aspx page locate and stream a file to an authenticated user and I'm getting the error:

Aspnet_wp.exe (PID:XXXX) stopped unexpectedly.

 

which the user sees as the Server Unavailable page.

 

I am aware of problems using Response.BinaryWrite or Response.WriteFile to download large files and so opted for the chunked method described in the microsoft KB article 812406.

 

The problem is that when a user cancels the download, the website stops responding. If the user then attempts to start a new download, either nothing happens or they get a Server Unavailable and my aspnet_wp.exe gets recycled.

 

If I step though the code and watch the file streaming out, then cancel the download before it completes, the loop continues for a while then stops. Hitting break and trying to check the values of the context, request or response objects gives me "error: cannot obtain value".

 

My attempts at using BinaryWrite and WriteFile met with similar problems. I have seen reference to a hotfix that adds a Response.TransferFile method but I'm not sure if this is caused by the same problem (aspnet running out of memory space), even though the symptoms are the same (recycled aspnet_wp.exe)

 

Has anyone had similar problems? if so, will the hotfix correct it?

 

I have found a few other posts on this problem around the net (mostly dated 1-2 years ago) but not a single response!

 

please help!

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Here's the download code before anyone asks! :)

 

    Dim iStream As System.IO.Stream

     ' Buffer to read 10K bytes in chunk:
     Dim buffer(10000) As Byte

     ' Length of the file:
     Dim length As Integer

     ' Total bytes to read:
     Dim dataToRead As Long

     ' Identify the file to download including its path.
     Dim filepath As String = "DownloadFileName"

     ' Identify the file name.
     Dim filename As String = System.IO.Path.GetFileName(filepath)

     Try
        ' Open the file.
        iStream = New System.IO.FileStream(filepath, System.IO.FileMode.Open, _
                                               IO.FileAccess.Read, IO.FileShare.Read)

        ' Total bytes to read:
        dataToRead = iStream.Length
        
        Response.ContentType = "application/octet-stream"
        Response.AddHeader("Content-Disposition", "attachment; filename=" & filename)

        ' Read the bytes.
           While dataToRead > 0
               ' Verify that the client is connected.
               If Response.IsClientConnected Then
                   ' Read the data in buffer
                   length = iStream.Read(buffer, 0, 10000)

                   ' Write the data to the current output stream.
                   Response.OutputStream.Write(buffer, 0, length)

                   ' Flush the data to the HTML output.
                   Response.Flush()

                   ReDim buffer(10000) ' Clear the buffer
                   dataToRead = dataToRead - length
               Else
                   'prevent infinite loop if user disconnects
                   dataToRead = -1
               End If
           End While

     Catch ex As Exception
        ' Trap the error, if any.
        Response.Write("Error : " & ex.Message)
     Finally
        If IsNothing(iStream) = False Then
           ' Close the file.
           iStream.Close()
        End If
     End Try

[Derek Stone]

Does the Application Event Log (Administrative Tools | Event Viewer) offer any more information? Which version of the .NET Framework are you using?

 

In regards to the hotfix you're talking about:

http://support.microsoft.com/default.aspx?scid=kb;en-us;823409

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The entire event viewer error message - so no, not all that helpful unfortunately..

 

Event Type: Error

Event Source: ASP.NET 1.1.4322.0

Event Category: None

Event ID: 1000

Date: 30/04/2004

Time: 3:24:44 PM

User: N/A

Computer: SERVER01

Description:

aspnet_wp.exe (PID: 4508) stopped unexpectedly.

 

 

and yes, that is the hotfix I've read about. I may have to just call microsoft and explain this problem to them. I expect they'll just tell me to apply the hotfix.