Imports System.Collections.Generic
Imports System.Net
Imports System.IO
Imports System.Text.RegularExpressions


Namespace Utilities

#Region "FTP client class"
    ''' <summary>
    ''' A wrapper class for .NET 2.0 FTP
    ''' </summary>
    ''' <remarks>
    ''' This class does not hold open an FTP connection but
    ''' instead is stateless: for each FTP request it
    ''' connects, performs the request and disconnects.
    ''' </remarks>
    Public Class FTPclient

#Region "CONSTRUCTORS"
        ''' <summary>
        ''' Blank constructor
        ''' </summary>
        ''' <remarks>Hostname, username and password must be set manually</remarks>
        Sub New()
        End Sub

        ''' <summary>
        ''' Constructor just taking the hostname
        ''' </summary>
        ''' <param name="Hostname">in either ftp://ftp.host.com or ftp.host.com form</param>
        ''' <remarks></remarks>
        Sub New(ByVal Hostname As String)
            _hostname = Hostname
        End Sub

        ''' <summary>
        ''' Constructor taking hostname, username and password
        ''' </summary>
        ''' <param name="Hostname">in either ftp://ftp.host.com or ftp.host.com form</param>
        ''' <param name="Username">Leave blank to use 'anonymous' but set password to your email</param>
        ''' <param name="Password"></param>
        ''' <remarks></remarks>
        Sub New(ByVal Hostname As String, ByVal Username As String, ByVal Password As String)
            _hostname = Hostname
            _username = Username
            _password = Password
        End Sub
#End Region

#Region "Directory functions"
        ''' <summary>
        ''' Return a simple directory listing
        ''' </summary>
        ''' <param name="directory">Directory to list, e.g. /pub</param>
        ''' <returns>A list of filenames and directories as a List(of String)</returns>
        ''' <remarks>For a detailed directory listing, use ListDirectoryDetail</remarks>
        Public Function ListDirectory(Optional ByVal directory As String = "") As List(Of String)
            'return a simple list of filenames in directory
            Dim ftp As Net.FtpWebRequest = GetRequest(GetDirectory(directory))
            'Set request to do simple list
            ftp.Method = Net.WebRequestMethods.Ftp.ListDirectory

            Dim str As String = GetStringResponse(ftp)
            'replace CRLF to CR, remove last instance
            str = str.Replace(vbCrLf, vbCr).TrimEnd(Chr(13))
            'split the string into a list
            Dim result As New List(Of String)
            result.AddRange(str.Split(Chr(13)))
            Return result
        End Function

        ''' <summary>
        ''' Return a detailed directory listing
        ''' </summary>
        ''' <param name="directory">Directory to list, e.g. /pub/etc</param>
        ''' <returns>An FTPDirectory object</returns>
        Public Function ListDirectoryDetail(Optional ByVal directory As String = "") As FTPdirectory
            Dim ftp As Net.FtpWebRequest = GetRequest(GetDirectory(directory))
            'Set request to do simple list
            ftp.Method = Net.WebRequestMethods.Ftp.ListDirectoryDetails

            Dim str As String = GetStringResponse(ftp)
            'replace CRLF to CR, remove last instance
            str = str.Replace(vbCrLf, vbCr).TrimEnd(Chr(13))
            'split the string into a list
            Return New FTPdirectory(str, _lastDirectory)
        End Function

#End Region

#Region "Upload: File transfer TO ftp server"
        ''' <summary>
        ''' Copy a local file to the FTP server
        ''' </summary>
        ''' <param name="localFilename">Full path of the local file</param>
        ''' <param name="targetFilename">Target filename, if required</param>
        ''' <returns></returns>
        ''' <remarks>If the target filename is blank, the source filename is used
        ''' (assumes current directory). Otherwise use a filename to specify a name
        ''' or a full path and filename if required.</remarks>
        Public Function Upload(ByVal localFilename As String, Optional ByVal targetFilename As String = "") As Boolean
            '1. check source
            If Not File.Exists(localFilename) Then
                Throw New ApplicationException("File " & localFilename & " not found")
            End If
            'copy to FI
            Dim fi As New FileInfo(localFilename)
            Return Upload(fi, targetFilename)
        End Function

        ''' <summary>
        ''' Upload a local file to the FTP server
        ''' </summary>
        ''' <param name="fi">Source file</param>
        ''' <param name="targetFilename">Target filename (optional)</param>
        ''' <returns></returns>
        Public Function Upload(ByVal fi As FileInfo, Optional ByVal targetFilename As String = "") As Boolean
            'copy the file specified to target file: target file can be full path or just filename (uses current dir)

            '1. check target
            Dim target As String
            If targetFilename.Trim = "" Then
                'Blank target: use source filename & current dir
                target = Me.CurrentDirectory & fi.Name
            ElseIf targetFilename.Contains("/") Then
                'If contains / treat as a full path
                target = AdjustDir(targetFilename)
            Else
                'otherwise treat as filename only, use current directory
                target = CurrentDirectory & targetFilename
            End If

            Dim URI As String = Hostname & target
            'perform copy
            Dim ftp As Net.FtpWebRequest = GetRequest(URI)

            'Set request to upload a file in binary
            ftp.Method = Net.WebRequestMethods.Ftp.UploadFile
            ftp.UseBinary = True

            'Notify FTP of the expected size
            ftp.ContentLength = fi.Length

            'create byte array to store: ensure at least 1 byte!
            Const BufferSize As Integer = 2048
            Dim content(BufferSize - 1) As Byte, dataRead As Integer

            'open file for reading
            Using fs As FileStream = fi.OpenRead()
                Try
                    'open request to send
                    Using rs As Stream = ftp.GetRequestStream
                        Do
                            dataRead = fs.Read(content, 0, BufferSize)
                            rs.Write(content, 0, dataRead)
                        Loop Until dataRead < BufferSize
                        rs.Close()
                    End Using
                Catch ex As Exception

                Finally
                    'ensure file closed
                    fs.Close()
                End Try

            End Using

            ftp = Nothing
            Return True

        End Function
#End Region

#Region "Download: File transfer FROM ftp server"
        ''' <summary>
        ''' Copy a file from FTP server to local
        ''' </summary>
        ''' <param name="sourceFilename">Target filename, if required</param>
        ''' <param name="localFilename">Full path of the local file</param>
        ''' <returns></returns>
        ''' <remarks>Target can be blank (use same filename), or just a filename
        ''' (assumes current directory) or a full path and filename</remarks>
        Public Function Download(ByVal sourceFilename As String, ByVal localFilename As String, Optional ByVal PermitOverwrite As Boolean = False) As Boolean
            '2. determine target file
            Dim fi As New FileInfo(localFilename)
            Return Me.Download(sourceFilename, fi, PermitOverwrite)
        End Function

        'Version taking an FtpFileInfo
        Public Function Download(ByVal file As FTPfileInfo, ByVal localFilename As String, Optional ByVal PermitOverwrite As Boolean = False) As Boolean
            Return Me.Download(file.FullName, localFilename, PermitOverwrite)
        End Function

        'Another version taking FtpFileInfo and FileInfo
        Public Function Download(ByVal file As FTPfileInfo, ByVal localFI As FileInfo, Optional ByVal PermitOverwrite As Boolean = False) As Boolean
            Return Me.Download(file.FullName, localFI, PermitOverwrite)
        End Function

        'Version taking string/FileInfo
        Public Function Download(ByVal sourceFilename As String, ByVal targetFI As FileInfo, Optional ByVal PermitOverwrite As Boolean = False) As Boolean
            '1. check target
            If targetFI.Exists And Not (PermitOverwrite) Then Throw New ApplicationException("Target file already exists")

            '2. check source
            Dim target As String
            If sourceFilename.Trim = "" Then
                Throw New ApplicationException("File not specified")
            ElseIf sourceFilename.Contains("/") Then
                'treat as a full path
                target = AdjustDir(sourceFilename)
            Else
                'treat as filename only, use current directory
                target = CurrentDirectory & sourceFilename
            End If

            Dim URI As String = Hostname & target

            '3. perform copy
            Dim ftp As Net.FtpWebRequest = GetRequest(URI)

            'Set request to download a file in binary mode
            ftp.Method = Net.WebRequestMethods.Ftp.DownloadFile
            ftp.UseBinary = True

            'open request and get response stream
            Using response As FtpWebResponse = CType(ftp.GetResponse, FtpWebResponse)
                Using responseStream As Stream = response.GetResponseStream
                    'loop to read & write to file
                    Using fs As FileStream = targetFI.OpenWrite
                        Try
                            Dim buffer(2047) As Byte
                            Dim read As Integer = 0
                            Do
                                read = responseStream.Read(buffer, 0, buffer.Length)
                                fs.Write(buffer, 0, read)
                            Loop Until read = 0
                            responseStream.Close()
                            fs.Flush()
                            fs.Close()
                        Catch ex As Exception
                            'catch error and delete file only partially downloaded
                            fs.Close()
                            'delete target file as it's incomplete
                            targetFI.Delete()
                            Throw
                        End Try
                    End Using
                    responseStream.Close()
                End Using
                response.Close()
            End Using

            Return True
        End Function
#End Region

#Region "Other functions: Delete rename etc."
        ''' <summary>
        ''' Delete remote file
        ''' </summary>
        ''' <param name="filename">filename or full path</param>
        ''' <returns></returns>
        ''' <remarks></remarks>
        Public Function FtpDelete(ByVal filename As String) As Boolean
            'Determine if file or full path
            Dim URI As String = Me.Hostname & GetFullPath(filename)

            Dim ftp As Net.FtpWebRequest = GetRequest(URI)
            'Set request to delete
            ftp.Method = Net.WebRequestMethods.Ftp.DeleteFile
            Try
                'get response but ignore it
                Dim str As String = GetStringResponse(ftp)
            Catch ex As Exception
                Return False
            End Try
            Return True
        End Function

        ''' <summary>
        ''' Determine if file exists on remote FTP site
        ''' </summary>
        ''' <param name="filename">Filename (for current dir) or full path</param>
        ''' <returns></returns>
        ''' <remarks>Note this only works for files</remarks>
        Public Function FtpFileExists(ByVal filename As String) As Boolean
            'Try to obtain filesize: if we get error msg containing "550"
            'the file does not exist
            Try
                Dim size As Long = GetFileSize(filename)
                Return True

            Catch ex As Exception
                'only handle expected not-found exception
                If TypeOf ex Is System.Net.WebException Then
                    'file does not exist/no rights error = 550
                    If ex.Message.Contains("550") Then
                        'clear
                        Return False
                    Else
                        Throw
                    End If
                Else
                    Throw
                End If
            End Try
        End Function

        ''' <summary>
        ''' Determine size of remote file
        ''' </summary>
        ''' <param name="filename"></param>
        ''' <returns></returns>
        ''' <remarks>Throws an exception if file does not exist</remarks>
        Public Function GetFileSize(ByVal filename As String) As Long
            Dim path As String
            If filename.Contains("/") Then
                path = AdjustDir(filename)
            Else
                path = Me.CurrentDirectory & filename
            End If
            Dim URI As String = Me.Hostname & path
            Dim ftp As Net.FtpWebRequest = GetRequest(URI)
            'Try to get info on file/dir?
            ftp.Method = Net.WebRequestMethods.Ftp.GetFileSize
            Dim tmp As String = Me.GetStringResponse(ftp)
            Return GetSize(ftp)
        End Function

        Public Function FtpRename(ByVal sourceFilename As String, ByVal newName As String) As Boolean
            'Does file exist?
            Dim source As String = GetFullPath(sourceFilename)
            If Not FtpFileExists(source) Then
                Throw New FileNotFoundException("File " & source & " not found")
            End If

            'build target name, ensure it does not exist
            Dim target As String = GetFullPath(newName)
            If target = source Then
                Throw New ApplicationException("Source and target are the same")
            ElseIf FtpFileExists(target) Then
                Throw New ApplicationException("Target file " & target & " already exists")
            End If

            'perform rename
            Dim URI As String = Me.Hostname & source

            Dim ftp As Net.FtpWebRequest = GetRequest(URI)
            'Set request to delete
            ftp.Method = Net.WebRequestMethods.Ftp.Rename
            ftp.RenameTo = target
            Try
                'get response but ignore it
                Dim str As String = GetStringResponse(ftp)
            Catch ex As Exception
                Return False
            End Try
            Return True
        End Function

        Public Function FtpCreateDirectory(ByVal dirpath As String) As Boolean
            'perform create
            Dim URI As String = Me.Hostname & AdjustDir(dirpath)
            Dim ftp As Net.FtpWebRequest = GetRequest(URI)
            'Set request to MkDir
            ftp.Method = Net.WebRequestMethods.Ftp.MakeDirectory
            Try
                'get response but ignore it
                Dim str As String = GetStringResponse(ftp)
            Catch ex As Exception
                Return False
            End Try
            Return True
        End Function

        Public Function FtpDeleteDirectory(ByVal dirpath As String) As Boolean
            'perform remove
            Dim URI As String = Me.Hostname & AdjustDir(dirpath)
            Dim ftp As Net.FtpWebRequest = GetRequest(URI)
            'Set request to RmDir
            ftp.Method = Net.WebRequestMethods.Ftp.RemoveDirectory
            Try
                'get response but ignore it
                Dim str As String = GetStringResponse(ftp)
            Catch ex As Exception
                Return False
            End Try
            Return True
        End Function
#End Region

#Region "private supporting fns"
        'Get the basic FtpWebRequest object with the
        'common settings and security
        Public Function GetRequest(ByVal URI As String) As FtpWebRequest
            'create request
            Dim result As FtpWebRequest = CType(FtpWebRequest.Create(URI), FtpWebRequest)
            'Set the login details
            result.Credentials = GetCredentials()
            'Do not keep alive (stateless mode)
            result.KeepAlive = False
            Return result
        End Function


        ''' <summary>
        ''' Get the credentials from username/password
        ''' </summary>
        Private Function GetCredentials() As Net.ICredentials
            Return New Net.NetworkCredential(Username, Password)
        End Function

        ''' <summary>
        ''' returns a full path using CurrentDirectory for a relative file reference
        ''' </summary>
        Private Function GetFullPath(ByVal file As String) As String
            If file.Contains("/") Then
                Return AdjustDir(file)
            Else
                Return Me.CurrentDirectory & file
            End If
        End Function

        ''' <summary>
        ''' Amend an FTP path so that it always starts with /
        ''' </summary>
        ''' <param name="path">Path to adjust</param>
        ''' <returns></returns>
        ''' <remarks></remarks>
        Private Function AdjustDir(ByVal path As String) As String
            Return CStr(IIf(path.StartsWith("/"), "", "/")) & path
        End Function

        Private Function GetDirectory(Optional ByVal directory As String = "") As String
            Dim URI As String
            If directory = "" Then
                'build from current
                URI = Hostname & Me.CurrentDirectory
                _lastDirectory = Me.CurrentDirectory
            Else
                If Not directory.StartsWith("/") Then Throw New ApplicationException("Directory should start with /")
                URI = Me.Hostname & directory
                _lastDirectory = directory
            End If
            Return URI
        End Function

        'stores last retrieved/set directory
        Private _lastDirectory As String = ""

        ''' <summary>
        ''' Obtains a response stream as a string
        ''' </summary>
        ''' <param name="ftp">current FTP request</param>
        ''' <returns>String containing response</returns>
        ''' <remarks>FTP servers typically return strings with CR and
        ''' not CRLF. Use respons.Replace(vbCR, vbCRLF) to convert
        ''' to an MSDOS string</remarks>
        Private Function GetStringResponse(ByVal ftp As FtpWebRequest) As String
            'Get the result, streaming to a string
            Dim result As String = ""
            Using response As FtpWebResponse = CType(ftp.GetResponse, FtpWebResponse)
                Dim size As Long = response.ContentLength
                Using datastream As Stream = response.GetResponseStream
                    Using sr As New StreamReader(datastream)
                        result = sr.ReadToEnd()
                        sr.Close()
                    End Using
                    datastream.Close()
                End Using
                response.Close()
            End Using
            Return result
        End Function

        ''' <summary>
        ''' Gets the size of an FTP request
        ''' </summary>
        ''' <param name="ftp"></param>
        ''' <returns></returns>
        ''' <remarks></remarks>
        Private Function GetSize(ByVal ftp As FtpWebRequest) As Long
            Dim size As Long
            Using response As FtpWebResponse = CType(ftp.GetResponse, FtpWebResponse)
                size = response.ContentLength
                response.Close()
            End Using
            Return size
        End Function
#End Region

#Region "Properties"
        Private _hostname As String
        ''' <summary>
        ''' Hostname
        ''' </summary>
        ''' <value></value>
        ''' <remarks>Hostname can be in either the full URL format
        ''' ftp://ftp.myhost.com or just ftp.myhost.com
        ''' </remarks>
        Public Property Hostname() As String
            Get
                If _hostname.StartsWith("ftp://") Then
                    Return _hostname
                Else
                    Return "ftp://" & _hostname
                End If
            End Get
            Set(ByVal value As String)
                _hostname = value
            End Set
        End Property
        Private _username As String
        ''' <summary>
        ''' Username property
        ''' </summary>
        ''' <value></value>
        ''' <remarks>Can be left blank, in which case 'anonymous' is returned</remarks>
        Public Property Username() As String
            Get
                Return CStr(IIf(_username = "", "anonymous", _username))
            End Get
            Set(ByVal value As String)
                _username = value
            End Set
        End Property
        Private _password As String
        Public Property Password() As String
            Get
                Return _password
            End Get
            Set(ByVal value As String)
                _password = value
            End Set
        End Property

        ''' <summary>
        ''' The CurrentDirectory value
        ''' </summary>
        ''' <remarks>Defaults to the root '/'</remarks>
        Private _currentDirectory As String = "/"
        Public Property CurrentDirectory() As String
            Get
                'return directory, ensure it ends with /
                Return _currentDirectory & CStr(IIf(_currentDirectory.EndsWith("/"), "", "/"))
            End Get
            Set(ByVal value As String)
                If Not value.StartsWith("/") Then Throw New ApplicationException("Directory should start with /")
                _currentDirectory = value
            End Set
        End Property


#End Region

    End Class
#End Region

#Region "FTP file info class"
    ''' <summary>
    ''' Represents a file or directory entry from an FTP listing
    ''' </summary>
    ''' <remarks>
    ''' This class is used to parse the results from a detailed
    ''' directory list from FTP. It supports most formats of
    ''' </remarks>
    Public Class FTPfileInfo
        'Stores extended info about FTP file

#Region "Properties"
        Public ReadOnly Property FullName() As String
            Get
                Return Path & Filename
            End Get
        End Property
        Public ReadOnly Property Filename() As String
            Get
                Return _filename
            End Get
        End Property
        Public ReadOnly Property Path() As String
            Get
                Return _path
            End Get
        End Property
        Public ReadOnly Property FileType() As DirectoryEntryTypes
            Get
                Return _fileType
            End Get
        End Property
        Public ReadOnly Property Size() As Long
            Get
                Return _size
            End Get
        End Property
        Public ReadOnly Property FileDateTime() As Date
            Get
                Return _fileDateTime
            End Get
        End Property
        Public ReadOnly Property Permission() As String
            Get
                Return _permission
            End Get
        End Property
        Public ReadOnly Property Extension() As String
            Get
                Dim i As Integer = Me.Filename.LastIndexOf(".")
                If i >= 0 And i < (Me.Filename.Length - 1) Then
                    Return Me.Filename.Substring(i + 1)
                Else
                    Return ""
                End If
            End Get
        End Property
        Public ReadOnly Property NameOnly() As String
            Get
                Dim i As Integer = Me.Filename.LastIndexOf(".")
                If i > 0 Then
                    Return Me.Filename.Substring(0, i)
                Else
                    Return Me.Filename
                End If
            End Get
        End Property
        Private _filename As String
        Private _path As String
        Private _fileType As DirectoryEntryTypes
        Private _size As Long
        Private _fileDateTime As Date
        Private _permission As String

#End Region

        ''' <summary>
        ''' Identifies entry as either File or Directory
        ''' </summary>
        Public Enum DirectoryEntryTypes
            File
            Directory
        End Enum

        ''' <summary>
        ''' Constructor taking a directory listing line and path
        ''' </summary>
        ''' <param name="line">The line returned from the detailed directory list</param>
        ''' <param name="path">Path of the directory</param>
        ''' <remarks></remarks>
        Sub New(ByVal line As String, ByVal path As String)
            'parse line
            Dim m As Match = GetMatchingRegex(line)
            If m Is Nothing Then
                'failed
                Throw New ApplicationException("Unable to parse line: " & line)
            Else
                _filename = m.Groups("name").Value
                _path = path
                _size = CLng(m.Groups("size").Value)
                _permission = m.Groups("permission").Value
                Dim _dir As String = m.Groups("dir").Value
                If (_dir <> "" And _dir <> "-") Then
                    _fileType = DirectoryEntryTypes.Directory
                Else
                    _fileType = DirectoryEntryTypes.File
                End If

                Try
                    _fileDateTime = Date.Parse(m.Groups("timestamp").Value)
                Catch ex As Exception
                    _fileDateTime = Nothing
                End Try

            End If
        End Sub

        Private Function GetMatchingRegex(ByVal line As String) As Match
            Dim rx As Regex, m As Match
            For i As Integer = 0 To _ParseFormats.Length - 1
                rx = New Regex(_ParseFormats(i))
                m = rx.Match(line)
                If m.Success Then Return m
            Next
            Return Nothing
        End Function

#Region "Regular expressions for parsing LIST results"
        ''' <summary>
        ''' List of REGEX formats for different FTP server listing formats
        ''' </summary>
        ''' <remarks>
        ''' The first three are various UNIX/LINUX formats, fourth is for MS FTP
        ''' in detailed mode and the last for MS FTP in 'DOS' mode.
        ''' I wish VB.NET had support for Const arrays like C# but there you go
        ''' </remarks>
        Private Shared _ParseFormats As String() = { _
            "(?<dir>[\-d])(?<permission>([\-r][\-w][\-xs]){3})\s+\d+\s+\w+\s+\w+\s+(?<size>\d+)\s+(?<timestamp>\w+\s+\d+\s+\d{4})\s+(?<name>.+)", _
            "(?<dir>[\-d])(?<permission>([\-r][\-w][\-xs]){3})\s+\d+\s+\d+\s+(?<size>\d+)\s+(?<timestamp>\w+\s+\d+\s+\d{4})\s+(?<name>.+)", _
            "(?<dir>[\-d])(?<permission>([\-r][\-w][\-xs]){3})\s+\d+\s+\d+\s+(?<size>\d+)\s+(?<timestamp>\w+\s+\d+\s+\d{1,2}:\d{2})\s+(?<name>.+)", _
            "(?<dir>[\-d])(?<permission>([\-r][\-w][\-xs]){3})\s+\d+\s+\w+\s+\w+\s+(?<size>\d+)\s+(?<timestamp>\w+\s+\d+\s+\d{1,2}:\d{2})\s+(?<name>.+)", _
            "(?<dir>[\-d])(?<permission>([\-r][\-w][\-xs]){3})(\s+)(?<size>(\d+))(\s+)(?<ctbit>(\w+\s\w+))(\s+)(?<size2>(\d+))\s+(?<timestamp>\w+\s+\d+\s+\d{2}:\d{2})\s+(?<name>.+)", _
            "(?<timestamp>\d{2}\-\d{2}\-\d{2}\s+\d{2}:\d{2}[Aa|Pp][mM])\s+(?<dir>\<\w+\>){0,1}(?<size>\d+){0,1}\s+(?<name>.+)"}
#End Region
    End Class
#End Region

#Region "FTP Directory class"
    ''' <summary>
    ''' Stores a list of files and directories from an FTP result
    ''' </summary>
    ''' <remarks></remarks>
    Public Class FTPdirectory
        Inherits List(Of FTPfileInfo)

        Sub New()
            'creates a blank directory listing
        End Sub

        ''' <summary>
        ''' Constructor: create list from a (detailed) directory string
        ''' </summary>
        ''' <param name="dir">directory listing string</param>
        ''' <param name="path"></param>
        ''' <remarks></remarks>
        Sub New(ByVal dir As String, ByVal path As String)
            For Each line As String In dir.Replace(vbLf, "").Split(CChar(vbCr))
                'parse
                If line <> "" Then Me.Add(New FTPfileInfo(line, path))
            Next
        End Sub

        ''' <summary>
        ''' Filter out only files from directory listing
        ''' </summary>
        ''' <param name="ext">optional file extension filter</param>
        ''' <returns>FTPdirectory listing</returns>
        Public Function GetFiles(Optional ByVal ext As String = "") As FTPdirectory
            Return Me.GetFileOrDir(FTPfileInfo.DirectoryEntryTypes.File, ext)
        End Function

        ''' <summary>
        ''' Returns a list of only subdirectories
        ''' </summary>
        ''' <returns>FTPDirectory list</returns>
        ''' <remarks></remarks>
        Public Function GetDirectories() As FTPdirectory
            Return Me.GetFileOrDir(FTPfileInfo.DirectoryEntryTypes.Directory)
        End Function

        'internal: share use function for GetDirectories/Files
        Private Function GetFileOrDir(ByVal type As FTPfileInfo.DirectoryEntryTypes, Optional ByVal ext As String = "") As FTPdirectory
            Dim result As New FTPdirectory()
            For Each fi As FTPfileInfo In Me
                If fi.FileType = type Then
                    If ext = "" Then
                        result.Add(fi)
                    ElseIf ext = fi.Extension Then
                        result.Add(fi)
                    End If
                End If
            Next
            Return result

        End Function

        Public Function FileExists(ByVal filename As String) As Boolean
            For Each ftpfile As FTPfileInfo In Me
                If ftpfile.Filename = filename Then
                    Return True
                End If
            Next
            Return False
        End Function

        Private Const slash As Char = "/"

        Public Shared Function GetParentDirectory(ByVal dir As String) As String
            Dim tmp As String = dir.TrimEnd(slash)
            Dim i As Integer = tmp.LastIndexOf(slash)
            If i > 0 Then
                Return tmp.Substring(0, i - 1)
            Else
                Throw New ApplicationException("No parent for root")
            End If
        End Function
    End Class
#End Region

End Namespace