Delete FTP files with name containing a string (matching mask) - vb.net

Question

I would like to delete all files on an FTP server, whose names contain a certain string.
For example I have these files on the FTP:
pippo_1.jpg
pippo_2.jpg
pippo_3.jpg
pluto_1.jpg
I would like delete all file that contain pippo.
How can I delete all these files with a single operation?
Thank you!

Answer 1

No implementation of the FTP protocol in .NET framework allows this in a single operation.
You have to list the remote directory, filter the files you want to delete and delete them one by one.
If you really want to do this in a single operation, you have use a 3rd party library, that supports operations with file masks. For example WinSCP .NET assembly allows this with its Session.RemoveFiles method:
Dim sessionOptions As New SessionOptions
With sessionOptions
.Protocol = Protocol.Ftp
.HostName = "ftp.example.com"
.UserName = "username"
.Password = "password"
End With
Using session As New Session
session.Open(sessionOptions)
session.RemoveFiles("/remote/path/pippo*").Check()
End Using
(I'm the author of WinSCP)
If you do not want to use a 3rd party library, do as suggested above:
Dim url As String = "ftp://ftp.example.com/remote/path/"
Dim credentials As NetworkCredential = New NetworkCredential("username", "password")
Dim listRequest As FtpWebRequest = WebRequest.Create(url)
listRequest.Method = WebRequestMethods.Ftp.ListDirectory
listRequest.Credentials = credentials
Using listResponse As FtpWebResponse = listRequest.GetResponse(),
listStream As Stream = listResponse.GetResponseStream(),
listReader As StreamReader = New StreamReader(listStream)
While Not listReader.EndOfStream
Dim filename As String = listReader.ReadLine()
If filename.StartsWith("pippo") Then
Dim deleteRequest As FtpWebRequest = WebRequest.Create(url + filename)
deleteRequest.Method = WebRequestMethods.Ftp.DeleteFile
deleteRequest.Credentials = credentials
deleteRequest.GetResponse()
End If
End While
End Using