使用FTP下载每个文件*WHILE*获取文件列表

Question

我们需要使用vb.net从远程FTP服务器获取大约100个非常小的文件.我们公司不会让我们购买(或安装)任何第三方ftp库...因此我们被迫使用类似FtpWebRequest的东西.(或者是否有更好的免费,选择已经是Visual Studio的一部分？)

这种方法有效,但速度非常慢.(我假设因为不断登录/退出.)

Log in with user name and password.
Get a file-list from the remote server.
Log out
Use that file-list to get each file separtely:
Log in, get the file, log out.
Log in 99 more times, get each file, log out each time.

相反,我们可能应该这样做,但它永远不会起作用:

Log in with user name and password.  ONCE.
Get a list of filenames.
Download each file.
Log out ONCE.

我们在网上找到了"获取FTP文件列表"以及后来"如何用FTP下载1个文件"的在线例子......但我们从未看到"获取每个文件名,现在就下载".

Dim fwr As Net.FtpWebRequest = Net.FtpWebRequest.Create(ftpSite)
fwr.Credentials = New NetworkCredential(userName, password)
fwr.KeepAlive = True
fwr.Method = WebRequestMethods.Ftp.ListDirectory

   Dim sr As IO.StreamReader = Nothing
   Try
      sr = New IO.StreamReader(fwr.GetResponse().GetResponseStream())
      Do Until (sr.EndOfStream())
         fileName = sr.ReadLine()

         fwr.Method = WebRequestMethods.Ftp.DownloadFile

         output = ""
         Dim sr2 As IO.StreamReader = Nothing
         Try
            sr2 = New IO.StreamReader(fwr.GetResponse().GetResponseStream())
            output = sr2.ReadToEnd()

         Catch ex As Exception

         End Try

         If (Not sr2 Is Nothing) Then sr2.Close() : sr2 = Nothing

         Call MsgBox("Got " & fileName & LF & output)
        Loop

   Catch ex As Exception

   End Try

   If (Not sr Is Nothing) Then sr.Close() : sr = Nothing
   If (Not fwr Is Nothing) Then fwr = Nothing

Answer 1

我刚刚放在一起的东西，重要的部分是 fwr.Proxy = Nothing，否则它会尝试自动获取代理设置，这会导致巨大的延迟，因此将其设置为无会强制它不使用代理设置。

如果您使用代理，显然您需要将其设置为实际代理。

Dim fwr As Net.FtpWebRequest = Net.FtpWebRequest.Create(ftpAddress)
fwr.Credentials = New NetworkCredential(userName, password)
fwr.KeepAlive = True
fwr.Method = WebRequestMethods.Ftp.ListDirectory
fwr.Proxy = Nothing

Try
    Dim sr As New IO.StreamReader(fwr.GetResponse().GetResponseStream())
    Dim lst = sr.ReadToEnd().Split(vbNewLine)
    For Each file As String In lst
        file = file.Trim() 'remove any whitespace
        If file = ".." OrElse file = "." Then Continue For
        Dim fwr2 As Net.FtpWebRequest = Net.FtpWebRequest.Create(ftpAddress & file)
        fwr2.Credentials = fwr.Credentials
        fwr2.KeepAlive = True
        fwr2.Method = WebRequestMethods.Ftp.DownloadFile
        fwr2.Proxy = Nothing

        Dim fileSR As New IO.StreamReader(fwr2.GetResponse().GetResponseStream())
        Dim fileData = fileSR.ReadToEnd()
        fileSR.Close()
    Next

    sr.Close()
Catch ex As Exception
End Try

我知道有点晚了但希望有帮助