File download with ASp

Posted on 2011-03-03
Last Modified: 2012-05-11
I am using the following code to allow signed-in users to download a pdf. The download works but then adobe reports that the file is damaged. NOTE: the file on the server is NOT damaged - the corruption seems to occur during download.

leadno = request("leadno")
filename =  "OBS"   & leadno & ".pdf"

strFilePath = "D:\inetpub\vhosts\xxxxxxxxxx\httpsdocs\observations\"   & filename
Set objFSO = Server.CreateObject("Scripting.FileSystemObject")
If objFSO.FileExists(strFilePath) Then
Set objFile = objFSO.GetFile(strFilePath)
intFileSize = objFile.Size
Set objFile = Nothing

strFileName = filename
strFileName = replace(filename," ","-")
Response.AddHeader "Content-Disposition","attachment; filename=" & strFileName

Response.ContentType = "application/x-msdownload"
Response.AddHeader "Content-Length", intFileSize

Set objStream = Server.CreateObject("ADODB.Stream")
objStream.Type = 1 'adTypeBinary
objStream.LoadFromFile strFilePath
Do While Not objStream.EOS And Response.IsClientConnected
Response.BinaryWrite objStream.Read(1024)
Set objStream = Nothing
Response.write "...Error finding file."
Response.write "..Error finding file."
End if
Set objFSO = Nothing
Question by:cdjohn31
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LVL 14

Expert Comment

ID: 35026250
Put this as content type:

Response.ContentType = "application/pdf"

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LVL 14

Expert Comment

ID: 35026259
To force download, put this:

Response.ContentType = "application/octet-stream"

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Author Comment

ID: 35027708
I have tried both of these - same result
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LVL 14

Expert Comment

ID: 35027830
Are those download files bigger or smaller then original ones? What is their size after download?


Author Comment

ID: 35047108
The size on the server and after download are identical
LVL 28

Accepted Solution

sybe earned 500 total points
ID: 35055943
Your code supposes that the file has a size that is an exact multiple of 1024 bytes. That is probably not the case.

I use a function as below.
Sub WriteFileToBrowser(ByVal sFilePath, ByVal sContentType, ByVal sDisplayName)
    Dim oStream, bBuffer, iFileSize, iChunk, i

    Response.Buffer = False
    Server.ScriptTimeout = 30000
    iChunk = 64000

    Set oStream = Server.CreateObject("ADODB.Stream")
    oStream.Type = 1
    oStream.LoadFromFile sFilePath
    iFileSize = oStream.Size

    Response.ContentType = sContentType
    Response.AddHeader "Content-Disposition", "filename=" & sDisplayName
    Response.AddHeader "Content-Length", oStream.Size

    For i = 1 To iFileSize \ iChunk
        If Not Response.IsClientConnected Then Exit For
        Response.BinaryWrite oStream.Read(iChunk)

    If iFileSize Mod iChunk > 0 Then
        If Response.IsClientConnected Then
            Response.BinaryWrite oStream.Read(iFileSize Mod iChunk)
        End If
    End If
    Set oStream = Nothing
End Sub

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