[英]How to download directories from FTP using VB.NET
我正在嘗試將多個目錄從 FTP 服務器下載到我的本地機器,
我試過這個,
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
但這里的問題是我可以從文件夾下載多個文件,但無法從主目錄下載子目錄及其內容。
基本上主目錄由文件和子目錄組成。 那么有沒有辦法從FTP下載子目錄及其內容?
提前致謝。
將我對C# 的回答翻譯通過 FTP將所有文件和子目錄下載到 VB.NET:
FtpWebRequest
對遞歸文件下載(或任何其他遞歸操作)沒有任何明確的支持。 您必須自己實現遞歸:
一個棘手的部分是從子目錄中識別文件。 無法使用FtpWebRequest
以可移植的方式做到這一點。 不幸的是, FtpWebRequest
不支持MLSD
命令,這是在 FTP 協議中檢索具有文件屬性的目錄列表的唯一可移植方式。 另請參閱檢查 FTP 服務器上的對象是文件還是目錄。
您的選擇是:
LIST
命令 = ListDirectoryDetails
方法)並嘗試解析特定於服務器的列表。 許多 FTP 服務器使用 *nix 樣式的列表,您可以通過條目開頭的d
標識目錄。 但是許多服務器使用不同的格式。 以下示例使用此方法(假設為 *nix 格式)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
使用如下函數:
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")
如果您想避免解析特定於服務器的目錄列表格式的麻煩,請使用支持MLSD
命令和/或解析各種LIST
列表格式的第 3 方庫; 和遞歸下載。
例如,使用WinSCP .NET 程序集,您可以通過一次調用Session.GetFiles
來下載整個目錄:
' 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
如果服務器支持,WinSCP 在內部使用MLSD
命令。 如果沒有,它使用LIST
命令並支持數十種不同的列表格式。
Session.GetFiles
方法默認是遞歸的。
(我是 WinSCP 的作者)
查看我的 FTP 課程:非常簡單。
看看我的 FTP 類,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
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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