How to use VB.NET from FTP Download Directory

Question

I tried to download multiple directories from FTP server to my local machine,

I tried this,

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.Ft pWebResponse)
 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 the problem is that I can download from the folder Multiple files, but unable to download subdirectories and their contents from the main directory.

Basically, the main directory consists of files and subdirectories. So is there any possible way to download subdirectories and their contents from FTP?

Thanks in advance.

Answer 1

For C# Download all files and subdirectories through FTP’s answer is translated into VB.NET:

FtpWebRequest does not have any explicit support for recursive file download (or any other recursive operation). You must implement recursion yourself:

>Column Out the remote directory
>Iterate the entries, download the files and recurse to the subdirectories (list them again, etc.)

One tricky part is to identify the files in the subdirectories. It cannot be done in a portable way using FtpWebRequest Up to this point. Unfortunately, FtpWebRequest does not support the MLSD command, which is the only portable way to retrieve a list of directories with file attributes in the FTP protocol. See also Checking if object on FTP server is file or directory.

Your choice is:

>Perform an operation on the file name, which will definitely fail on the file and succeed on the directory (or vice versa). That is, you can try to download the “name”. If Success, it is a file, if it fails, it is a directory.
>You may be lucky, in your specific case, you can tell the files in the directory by the file name (that is, all files have extensions, And subdirectories don’t)
> You use a long directory listing (LIST command = ListDirectoryDe The directory is identified by d. But many servers use different formats. The following example uses this method (assuming *nix format)

Sub DownloadFtpDirectory(
 url As String, credentials As NetworkCredential, localPath As String )
 Dim listRequest As FtpWebRequest = WebRequest.Create(url)
 listRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails
 listReques t.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.Create Directory(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 Wh ile read> 0
 End Using
 End If
 Next
End Sub

Use the following functions:

< pre>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 the trouble of parsing the server-specific directory list format, please use the one that supports MLSD commands and/or parsing various LIST list formats Third-party libraries; and recursive downloading.

For example, using WinSCP .NET assembly, you can download the entire directory by calling Session.GetFiles once:

< /p>

' 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\*" ).C heck()
End Using

Internally, if the server supports it, WinSCP uses the MLSD command. If not, it uses the LIST command and supports many different list formats.

By default, the Session.GetFiles method is recursive.

(I am the author of WinSCP)

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