Modules/Filesystem/File.vb

Imports System.IO
Imports DigitalData.Modules.Logging

''' <module>File</module>
''' <version>0.0.0.1</version>
''' <date>11.10.2018</date>
''' <summary>
''' Module that provides variouse File operations
''' </summary>
''' <dependencies>
''' NLog, >= 4.5.8
''' </dependencies>
''' <params>
''' LogConfig, DigitalData.Module.Logging.LogConfig
'''     A LogConfig object               
''' </params>
''' <props>
''' </props>
''' <example>
''' </example>
''' <remarks>
''' </remarks>
Public Class File
    Private ReadOnly _logger As Logger
    Private ReadOnly _logConfig As LogConfig

    Private Const FILE_NAME_ACCESS_TEST = "accessTest.txt"

    Public Sub New(LogConfig As LogConfig)
        _logConfig = LogConfig
        _logger = LogConfig.GetLogger()
    End Sub

    ''' <summary>
    ''' Removes files in a directory filtered by filename, extension and last write date
    ''' </summary>
    ''' <param name="Path">The directory in which files will be deleted</param>
    ''' <param name="FileKeepTime">Only delete files which are older than x days. Must be between 0 and 1000 days.</param>
    ''' <param name="FileBaseName">A filename filter which will be checked</param>
    ''' <param name="FileExtension">A file extension which will be checked</param>
    ''' <param name="ContinueOnError">Should the function continue with deleting when a file could not be deleted?</param>
    ''' <returns>True if all files were deleted or if no files were deleted, otherwise false</returns>
    Public Function RemoveFiles(Path As String, FileKeepTime As Integer, FileBaseName As String, Optional FileExtension As String = "log", Optional ContinueOnError As Boolean = True) As Boolean
        If Not TestPathIsDirectory(Path) Then
            Throw New ArgumentException($"Path {Path} is not a directory!")
        End If

        If Not Directory.Exists(Path) Then
            Throw New DirectoryNotFoundException($"Path {Path} does not exist!")
        End If

        If FileKeepTime < 0 Or FileKeepTime > 1000 Then
            Throw New ArgumentOutOfRangeException("FileKeepTime must be an integer between 0 and 1000!")
        End If

        Dim oUnableToDeleteCounter = 0
        Dim oDirectory As New DirectoryInfo(Path)
        Dim oDateLimit As DateTime = DateTime.Now.AddDays(FileKeepTime)
        Dim oFiles As List(Of FileInfo) = oDirectory.
            EnumerateFiles($"*{FileBaseName}*").
            Where(Function(oFileInfo As FileInfo)
                      Return oFileInfo.Extension = FileExtension And oFileInfo.LastWriteTime < oDateLimit
                  End Function)

        If oFiles.Count = 0 Then
            _logger.Debug("No files found that match the criterias.")
            Return True
        End If

        _logger.Debug("Deleting old files (Found {0}).", oFiles.Count)

        For Each oFile As FileInfo In oFiles
            Try
                oFile.Delete()
            Catch ex As Exception
                If ContinueOnError = False Then
                    _logger.Warn("Deleting files was aborted at file {0}.", oFile.FullName)
                    Return False
                End If
                oUnableToDeleteCounter = oUnableToDeleteCounter + 1
                _logger.Warn("File {0} could not be deleted!")
            End Try
        Next

        If oUnableToDeleteCounter > 0 Then
            _logger.Debug("Old files partially removed. {0} files could not be removed.", oUnableToDeleteCounter)
        Else
            _logger.Debug("Old files removed.")
        End If

        Return True
    End Function

    Public Sub MoveTo(FilePath As String, Directory As String)
        Dim oFileInfo As New FileInfo(FilePath)
        IO.File.Move(FilePath, Path.Combine(Directory, oFileInfo.Name))
    End Sub

    Public Sub MoveTo(FilePath As String, NewFileName As String, Directory As String)
        Dim oFileInfo As New FileInfo(FilePath)
        IO.File.Move(FilePath, Path.Combine(Directory, NewFileName))
    End Sub

    ''' <summary>
    ''' Tries to create a directory and returns its path.
    ''' Returns a temp path if `DirectoryPath` can not be created or written to.
    ''' </summary>
    ''' <param name="DirectoryPath">The directory to create</param>
    ''' <param name="TestWriteAccess">Should a write access test be performed?</param>
    ''' <returns>The used path</returns>
    Public Function CreateDirectory(DirectoryPath As String, Optional TestWriteAccess As Boolean = True) As String
        Dim oFinalPath As String
        If Directory.Exists(DirectoryPath) Then
            _logger.Debug("Directory {0} already exists. Skipping.", DirectoryPath)
            oFinalPath = DirectoryPath
        Else
            Try
                Directory.CreateDirectory(DirectoryPath)
                oFinalPath = DirectoryPath
            Catch ex As Exception
                _logger.Error(ex)
                _logger.Warn("Directory {0} could not be created. Temp path will be used instead.", DirectoryPath)
                oFinalPath = Path.GetTempPath()
            End Try
        End If

        If TestWriteAccess AndAlso Not TestPathIsWritable(DirectoryPath) Then
            _logger.Warn("Directory {0} is not writable. Temp path will be used instead.", DirectoryPath)
            oFinalPath = Path.GetTempPath()
        Else
            oFinalPath = DirectoryPath
        End If

        _logger.Debug("Using path {0}", oFinalPath)

        Return oFinalPath
    End Function

    Public Function TestPathIsWritable(DirectoryPath As String) As Boolean
        Try
            Dim fileAccessPath = Path.Combine(DirectoryPath, FILE_NAME_ACCESS_TEST)
            Using fs As FileStream = IO.File.Create(fileAccessPath)
                fs.WriteByte(0)
            End Using

            IO.File.Delete(fileAccessPath)
            Return True
        Catch ex As Exception
            Return False
        End Try
    End Function

    Public Function TestPathIsDirectory(Path As String) As Boolean
        If Not Directory.Exists(Path) Then
            Return False
        End If

        Dim oIsDirectory As Boolean = (System.IO.File.GetAttributes(Path) And FileAttributes.Directory) = FileAttributes.Directory
        Return oIsDirectory
    End Function

End Class