Question

我正在编写一个服务来下载，然后每个周末删除FTP站点的全部内容。

文件大小从2mb到8mb不等，初始下载大约为150,000+。在此之后，我希望下载范围是每周2000个文件。我打算安排服务在午夜左右运行。

这适用于一家供应商，如果一切正常，那么我们将每周与数百家供应商合作。

我对编写可靠服务的最佳实践感兴趣，能够下载如此大量的文件。

一些问题/疑虑：

处理异常和超时问题。
删除所有文件内容后正确删除空文件夹
如何确保没有人开始上传到我们即将删除的文件夹。
我是否应该考虑将任务分配到单独的服务中？
- 服务＃1 解析目录内容并将文件名保存到表中。
- 服务＃2下载并删除文件，如果目录为空，则删除该文件夹。

我只是在那里抛出一些想法;不要求任何人给我写任何东西。只是寻找关于如何构建这样的东西的想法。

Private Function GetStringResponse(ByVal ftp As FtpWebRequest) As String

            Dim response As FtpWebResponse = Nothing
            Dim datastream As Stream = Nothing
            Dim sr As StreamReader = Nothing
            Dim result As String = ""

            Try

                response = DirectCast(ftp.GetResponse, FtpWebResponse)

                Dim size As Long = response.ContentLength

                datastream = response.GetResponseStream

                sr = New StreamReader(datastream)

                result = sr.ReadToEnd()

            Finally
                If Not response Is Nothing Then
                    response.Close()
                End If
                If Not datastream Is Nothing Then
                    datastream.Close()
                End If
                If Not sr Is Nothing Then
                    sr.Close()
                End If

            End Try

            Return result

End Function


 Private Function GetRequest(ByVal URI As String, Optional p_KeepAlive As Boolean = False) As FtpWebRequest

            Dim result As FtpWebRequest = CType(FtpWebRequest.Create(URI), FtpWebRequest)
            If m_UserSsl Then
                Net.ServicePointManager.ServerCertificateValidationCallback = AddressOf ValidateCertificate
                result.EnableSsl = True
            End If


            result.Credentials = GetCredentials()

            result.KeepAlive = p_KeepAlive

            Return result

End Function


        Public Function GetDirectoryTree(p_Directory As String, Optional p_Mask As String = "") As List(Of String)

            Dim files As New List(Of String)
            Dim folders As New Queue(Of String)()
            Dim _resp As StreamReader = Nothing
            Dim _Ftp As Net.FtpWebRequest = Nothing

            folders.Enqueue(p_Directory)

            While folders.Count > 0
                Dim fld As String = folders.Dequeue()
                Dim newFiles As List(Of String)

                _Ftp = GetRequest(GetDirectory(fld), True)
                _Ftp.Method = Net.WebRequestMethods.Ftp.ListDirectory

                Dim response As String = GetStringResponse(_Ftp)

                If response.Length > 0 Then
                    newFiles = response.Replace(Convert.ToChar(13) + Convert.ToChar(10), Convert.ToChar(13)).TrimEnd(Convert.ToChar(13)).Split(Convert.ToChar(13)).ToList()
                    If p_Mask <> String.Empty Then newFiles = newFiles.Where(Function(x) x.ToUpper Like p_Mask.ToUpper).ToList
                Else
                    newFiles = New List(Of String)
                End If

                _Ftp = GetRequest(GetDirectory(fld), True)
                _Ftp.Method = WebRequestMethods.Ftp.ListDirectoryDetails

                Using resp As New StreamReader(_Ftp.GetResponse().GetResponseStream())
                    Dim line As String = resp.ReadLine()
                    While line IsNot Nothing
                        If line.Trim().ToLower().StartsWith("d") OrElse line.Contains(" <DIR> ") Then
                            Dim dir As String = newFiles.First(Function(x) line.EndsWith(x))
                            newFiles.Remove(dir)
                            folders.Enqueue(fld + dir + "/")
                        End If
                        line = resp.ReadLine()
                    End While
                End Using

                files.AddRange(newFiles.Select(Function(x) fld + x).ToList())
            End While

End Function

将整个FTP站点下载到本地网络驱动器的最佳实践（VB.NET）

0 个答案: