[英]How to download directories from FTP using VB.NET
I am trying to download multiple directories from FTP server to my local machine,我正在尝试将多个目录从 FTP 服务器下载到我的本地机器,
I have tried this,我试过这个,
Const localFile As String = "C:\Documents and Settings\cr\Desktop\T\New Folder\"
Const remoteFile As String = "textbox.Text"
Const host As String = "ftp://ftp.example.com"
Const username As String = "username"
Const password As String = "password"
For i1 = 0 To ListBox1.SelectedItems.Count - 1
Dim li As New ListViewItem
li = ListView1.Items.Add(ListBox1.SelectedItems(i1))
Dim URI1 As String = host + remoteFile & "/" & ListBox1.SelectedItems(i1)
Dim ftp1 As System.Net.FtpWebRequest = CType(FtpWebRequest.Create(URI1), FtpWebRequest)
ftp1.Credentials = New System.Net.NetworkCredential(username, password)
ftp1.KeepAlive = False
ftp1.UseBinary = True
ftp1.Method = System.Net.WebRequestMethods.Ftp.DownloadFile
Using response As System.Net.FtpWebResponse = CType(ftp1.GetResponse, System.Net.FtpWebResponse)
Using responseStream As IO.Stream = response.GetResponseStream
Dim length As Integer = response.ContentLength
Dim bytes(length) As Byte
'loop to read & write to file
Using fs As New IO.FileStream(localFile & ListBox1.SelectedItems(i1), IO.FileMode.Create)
Dim buffer(2047) As Byte
Dim read As Integer = 1
Do
read = responseStream.Read(buffer, 0, buffer.Length)
fs.Write(buffer, 0, read)
Loop Until read = 0 'see Note(1)
responseStream.Close()
fs.Flush()
fs.Close()
End Using
responseStream.Close()
End Using
response.Close()
End Using
li.BackColor = Color.Aquamarine
Next
But here the problem is that I am able to download multiple files from folders, but unable to download the sub directories and their contents from the main directory.但这里的问题是我可以从文件夹下载多个文件,但无法从主目录下载子目录及其内容。
Basically the main directory consist of files and sub directories both.基本上主目录由文件和子目录组成。 So is there any possible way to download sub directory and its contents from FTP?
那么有没有办法从FTP下载子目录及其内容?
Thanks in advance.提前致谢。
Translating my answer to C# Download all files and subdirectories through FTP to VB.NET:将我对C# 的回答翻译通过 FTP将所有文件和子目录下载到 VB.NET:
The FtpWebRequest
does not have any explicit support for recursive file download (or any other recursive operation). FtpWebRequest
对递归文件下载(或任何其他递归操作)没有任何明确的支持。 You have to implement the recursion yourself:您必须自己实现递归:
A tricky part is to identify files from subdirectories.一个棘手的部分是从子目录中识别文件。 There's no way to do that in a portable way with the
FtpWebRequest
.无法使用
FtpWebRequest
以可移植的方式做到这一点。 The FtpWebRequest
unfortunately does not support the MLSD
command, which is the only portable way to retrieve directory listing with file attributes in FTP protocol.不幸的是,
FtpWebRequest
不支持MLSD
命令,这是在 FTP 协议中检索具有文件属性的目录列表的唯一可移植方式。 See also Checking if object on FTP server is file or directory .另请参阅检查 FTP 服务器上的对象是文件还是目录。
Your options are:您的选择是:
LIST
command = ListDirectoryDetails
method) and try to parse a server-specific listing.LIST
命令 = ListDirectoryDetails
方法)并尝试解析特定于服务器的列表。 Many FTP servers use *nix-style listing, where you identify a directory by the d
at the very beginning of the entry.d
标识目录。 But many servers use a different format.Sub DownloadFtpDirectory(
url As String, credentials As NetworkCredential, localPath As String)
Dim listRequest As FtpWebRequest = WebRequest.Create(url)
listRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails
listRequest.Credentials = credentials
Dim lines As List(Of String) = New List(Of String)
Using listResponse As FtpWebResponse = listRequest.GetResponse(),
listStream As Stream = listResponse.GetResponseStream(),
listReader As StreamReader = New StreamReader(listStream)
While Not listReader.EndOfStream
lines.Add(listReader.ReadLine())
End While
End Using
For Each line As String In lines
Dim tokens As String() =
line.Split(New Char() {" "}, 9, StringSplitOptions.RemoveEmptyEntries)
Dim name As String = tokens(8)
Dim permissions As String = tokens(0)
Dim localFilePath As String = Path.Combine(localPath, name)
Dim fileUrl As String = url + name
If permissions(0) = "d" Then
If Not Directory.Exists(localFilePath) Then
Directory.CreateDirectory(localFilePath)
End If
DownloadFtpDirectory(fileUrl + "/", credentials, localFilePath)
Else
Dim downloadRequest As FtpWebRequest = WebRequest.Create(fileUrl)
downloadRequest.Method = WebRequestMethods.Ftp.DownloadFile
downloadRequest.Credentials = credentials
Using downloadResponse As FtpWebResponse = downloadRequest.GetResponse(),
sourceStream As Stream = downloadResponse.GetResponseStream(),
targetStream As Stream = File.Create(localFilePath)
Dim buffer As Byte() = New Byte(10240 - 1) {}
Dim read As Integer
Do
read = sourceStream.Read(buffer, 0, buffer.Length)
If read > 0 Then
targetStream.Write(buffer, 0, read)
End If
Loop While read > 0
End Using
End If
Next
End Sub
Use the function like:使用如下函数:
Dim credentials As NetworkCredential = New NetworkCredential("user", "mypassword")
Dim url As String = "ftp://ftp.example.com/directory/to/download/"
DownloadFtpDirectory(url, credentials, "C:\target\directory")
If you want to avoid troubles with parsing the server-specific directory listing formats, use a 3rd party library that supports the MLSD
command and/or parsing various LIST
listing formats;如果您想避免解析特定于服务器的目录列表格式的麻烦,请使用支持
MLSD
命令和/或解析各种LIST
列表格式的第 3 方库; and recursive downloads.和递归下载。
For example with WinSCP .NET assembly you can download whole directory with a single call to the Session.GetFiles
:例如,使用WinSCP .NET 程序集,您可以通过一次调用
Session.GetFiles
来下载整个目录:
' Setup session options
Dim SessionOptions As SessionOptions = New SessionOptions
With SessionOptions
.Protocol = Protocol.Ftp
.HostName = "ftp.example.com"
.UserName = "user"
.Password = "mypassword"
End With
Using session As Session = New Session()
' Connect
session.Open(SessionOptions)
' Download files
session.GetFiles("/directory/to/download/*", "C:\target\directory\*").Check()
End Using
Internally, WinSCP uses the MLSD
command, if supported by the server.如果服务器支持,WinSCP 在内部使用
MLSD
命令。 If not, it uses the LIST
command and supports dozens of different listing formats.如果没有,它使用
LIST
命令并支持数十种不同的列表格式。
The Session.GetFiles
method is recursive by default. Session.GetFiles
方法默认是递归的。
(I'm the author of WinSCP) (我是 WinSCP 的作者)
Check out my FTP class: Its pretty straight forward.查看我的 FTP 课程:非常简单。
Take a look at my FTP class, it might be exactly what you need.看看我的 FTP 类,它可能正是您所需要的。
Public Class FTP
'-------------------------[BroCode]--------------------------
'----------------------------FTP-----------------------------
Private _credentials As System.Net.NetworkCredential
Sub New(ByVal _FTPUser As String, ByVal _FTPPass As String)
setCredentials(_FTPUser, _FTPPass)
End Sub
Public Sub UploadFile(ByVal _FileName As String, ByVal _UploadPath As String)
Dim _FileInfo As New System.IO.FileInfo(_FileName)
Dim _FtpWebRequest As System.Net.FtpWebRequest = CType(System.Net.FtpWebRequest.Create(New Uri(_UploadPath)), System.Net.FtpWebRequest)
_FtpWebRequest.Credentials = _credentials
_FtpWebRequest.KeepAlive = False
_FtpWebRequest.Timeout = 20000
_FtpWebRequest.Method = System.Net.WebRequestMethods.Ftp.UploadFile
_FtpWebRequest.UseBinary = True
_FtpWebRequest.ContentLength = _FileInfo.Length
Dim buffLength As Integer = 2048
Dim buff(buffLength - 1) As Byte
Dim _FileStream As System.IO.FileStream = _FileInfo.OpenRead()
Try
Dim _Stream As System.IO.Stream = _FtpWebRequest.GetRequestStream()
Dim contentLen As Integer = _FileStream.Read(buff, 0, buffLength)
Do While contentLen <> 0
_Stream.Write(buff, 0, contentLen)
contentLen = _FileStream.Read(buff, 0, buffLength)
Loop
_Stream.Close()
_Stream.Dispose()
_FileStream.Close()
_FileStream.Dispose()
Catch ex As Exception
MessageBox.Show(ex.Message, "Upload Error: ", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End Sub
Public Sub DownloadFile(ByVal _FileName As String, ByVal _ftpDownloadPath As String)
Try
Dim _request As System.Net.FtpWebRequest = System.Net.WebRequest.Create(_ftpDownloadPath)
_request.KeepAlive = False
_request.Method = System.Net.WebRequestMethods.Ftp.DownloadFile
_request.Credentials = _credentials
Dim _response As System.Net.FtpWebResponse = _request.GetResponse()
Dim responseStream As System.IO.Stream = _response.GetResponseStream()
Dim fs As New System.IO.FileStream(_FileName, System.IO.FileMode.Create)
responseStream.CopyTo(fs)
responseStream.Close()
_response.Close()
Catch ex As Exception
MessageBox.Show(ex.Message, "Download Error: ", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End Sub
Public Function GetDirectory(ByVal _ftpPath As String) As List(Of String)
Dim ret As New List(Of String)
Try
Dim _request As System.Net.FtpWebRequest = System.Net.WebRequest.Create(_ftpPath)
_request.KeepAlive = False
_request.Method = System.Net.WebRequestMethods.Ftp.ListDirectoryDetails
_request.Credentials = _credentials
Dim _response As System.Net.FtpWebResponse = _request.GetResponse()
Dim responseStream As System.IO.Stream = _response.GetResponseStream()
Dim _reader As System.IO.StreamReader = New System.IO.StreamReader(responseStream)
Dim FileData As String = _reader.ReadToEnd
Dim Lines() As String = FileData.Split(New String() {Environment.NewLine}, StringSplitOptions.RemoveEmptyEntries)
For Each l As String In Lines
ret.Add(l)
Next
_reader.Close()
_response.Close()
Catch ex As Exception
MessageBox.Show(ex.Message, "Directory Fetch Error: ", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
Return ret
End Function
Private Sub setCredentials(ByVal _FTPUser As String, ByVal _FTPPass As String)
_credentials = New System.Net.NetworkCredential(_FTPUser, _FTPPass)
End Sub
End Class
To initialize:初始化:
Dim ftp As New FORM.FTP("username", "password")
ftp.UploadFile("c:\file.jpeg", "ftp://domain/file.jpeg")
ftp.DownloadFile("c:\file.jpeg", "ftp://ftp://domain/file.jpeg")
Dim directory As List(Of String) = ftp.GetDirectory("ftp://ftp.domain.net/")
ListBox1.Items.Clear()
For Each item As String In directory
ListBox1.Items.Add(item)
Next
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