[RESOLVED] Downloading files

[urbycoz]

I'm trying to write a windows app that will download files from a server. It is working fine for small files, but not the larger ones (50Mb+)- I get the error "An operation on a socket could not be performed because the system lacked
sufficient buffer space or because a queue was full."

This is the code I am using:

Private Function DownloadFile(ByVal fileSource As String, _
                                 ByVal fileDestination As String, _
                                 ByVal WebRequestType As String) As Boolean
        Dim myHttpWebRequest As HttpWebRequest
        Dim myHttpWebResponse As HttpWebResponse
        Dim myFileWebRequest As FileWebRequest
        Dim myFileWebResponse As FileWebResponse
        Dim myStream As Stream
        Dim bufferSize As Integer
        Dim inBuf() As Byte
        Dim bytesToRead As Integer
        Dim bytesRead As Integer = 0
        Dim myFileStream As FileStream
        Dim n As Integer
        Dim folderDestination As String
        'Dim PercentageComplete As Integer
        Dim clsUtils As New clsUtilities

        Try
            If WebRequestType = "HTTP" Then
                myHttpWebRequest = CType(WebRequest.Create(fileSource), HttpWebRequest)
                myHttpWebResponse = CType(myHttpWebRequest.GetResponse(), HttpWebResponse)
                myStream = myHttpWebResponse.GetResponseStream()
                bufferSize = myHttpWebResponse.ContentLength
            Else 'File
                myFileWebRequest = CType(WebRequest.Create(fileSource), FileWebRequest)
                myFileWebResponse = CType(myFileWebRequest.GetResponse(), FileWebResponse)
                myStream = myFileWebResponse.GetResponseStream()
                bufferSize = myFileWebResponse.ContentLength
            End If

            'MsgBox("bufferSize=" & bufferSize)

            'Set buffer size
            ReDim inBuf(bufferSize)
            bytesToRead = CInt(inBuf.Length)

            'Set up progressbar
            ResetLoadingPanel()
            DownloadProgressBar.Maximum = bufferSize

            While bytesToRead > 0
                n = myStream.Read(inBuf, bytesRead, bytesToRead)

                If n = 0 Then
                    Exit While
                End If
                bytesRead += n
                bytesToRead -= n

                'Update progress bar
                DownloadProgressBar.Step = n
                DownloadProgressBar.PerformStep()

                'Update Loading Panel
                UpdateLoadingPanel(DownloadProgressBar.Value, DownloadProgressBar.Maximum)
            End While

            'Remove existing files
            If Not clsUtils.FileExists(fileDestination) Then
                WriteToInstallInfo("File already exists. Deleting...", True, True)
                File.Delete(fileDestination)
                WriteToInstallInfo("...deleted ", False, False)
            End If

            'Create folder if required
            folderDestination = clsUtils.FolderFromFileName(fileDestination)
            If Not clsUtils.FolderExists(folderDestination) Then
                WriteToInstallInfo("Creating folder '" & folderDestination & "' ... ", True, True)
                Directory.CreateDirectory(folderDestination)
                WriteToInstallInfo("... created ", False, False)
            End If

            myFileStream = New FileStream(fileDestination, FileMode.OpenOrCreate, FileAccess.Write)
            myFileStream.Write(inBuf, 0, bytesRead)

            myStream.Close()
            myFileStream.Close()

            WriteToInstallInfo("...download successful.", True, True)
            Return True
        Catch ex As Exception
            WriteToInstallInfo("**ERROR** DownloadFile:" & ex.Message, True, True)
            Return False
        End Try
    End Function

If I can modify this method to work, then great. Otherwise, any ideas as to what I should be doing?

[urbycoz]

Found this method, which works great:

Function DownloadChunks(ByVal sURL As String, ByVal pProgress As ProgressBar, ByVal Filename As String)
        Dim wRemote As System.Net.WebRequest
        Dim URLReq As HttpWebRequest
        Dim URLRes As HttpWebResponse
        Dim FileStreamer As New FileStream(Filename, FileMode.Create)
        Dim bBuffer(999) As Byte
        Dim iBytesRead As Integer

        Try
            URLReq = WebRequest.Create(sURL)
            URLRes = URLReq.GetResponse
            Dim sChunks As Stream = URLReq.GetResponse.GetResponseStream
            pProgress.Maximum = URLRes.ContentLength

            Do
                iBytesRead = sChunks.Read(bBuffer, 0, 1000)
                FileStreamer.Write(bBuffer, 0, iBytesRead)
                If pProgress.Value + iBytesRead <= pProgress.Maximum Then
                    pProgress.Value += iBytesRead
                Else
                    pProgress.Value = pProgress.Maximum
                End If
            Loop Until iBytesRead = 0
            pProgress.Value = pProgress.Maximum
            sChunks.Close()
            FileStreamer.Close()
            Return sResponseData
        Catch
            MsgBox(Err.Description)
        End Try
    End Function

Presumably it works because it limits the size of the buffer.