In the developerWorks forum for Notes 8, a user asked about how to check if a file (in this particular instance attached to a Rich Text Lite field) is an Adobe PDF file. The easiest (but of course not fool proof) way is to simply check the extension of the file name.
That reminded me that I have a simple Lotusscript class with some file functions that would simplify the parsing of a filename, if you want to get the path, the file name or just the extension. I thought that perhaps more people could use this, so I am posting it below. Thanks to Andre Guirard for the code to create directories. That is a function I sometimes need when working with files, so I added that to the class for my convenience.
Option Public
Option Declare
Class FileObject
Private p_FileName As String
Private p_FilePath As String
Private p_Extension As String
Public Sub New()
End Sub
Public Property Set FileName As String
p_FileName = FileName
p_Extension = StrRightBack(FileName,".")
End Property
Public Property Get FileName As String
FileName = p_FileName
End Property
Public Function Extension() As String
Extension = p_Extension
End Function
Public Property Set FilePath As String
p_FilePath = FilePath
If Right(p_FilePath,1)<>"\" Then
p_FilePath = p_FilePath & "\"
End If
End Property
Public Property Get FilePath As String
FilePath = p_FilePath
End Property
Public Property Set FullPathName As String
Me.FilePath = StrLeftBack(FullPathName,"\")
Me.FileName = StrRightBack(FullPathName,"\")
End Property
Public Property Get FullPathName As String
FullPathName = p_FilePath & p_FileName
End Property
Public Sub MakeDir(Byval strWhere As String)
' *** This code by Andre Guirard @ IBM
' *** http://planetlotus.org/profiles/andre-guirard_22584
' *** Using an iterative method instead of recursive due to stack issues (see link above)
On Error 76 Goto parentDoesNotExist
Dim stack$
Const NL = {
}
Do
Mkdir strWhere
On Error Goto 0 ' first success, stop trapping errors; avoid infinite loop.
strWhere = Strleft(stack, NL) ' "pop" a path for next iteration
stack = Mid$(stack, Len(strWhere)+2)
failed:
Loop Until strWhere = ""
Exit Sub
parentDoesNotExist:
' This error code can indicate other problems, but assume missing parent.
' If not, we get a different error (75) later when trying to create the parent.
Dim fpath$, fname$
SplitFilepath strWhere, fpath, fname
If fpath = "" Then Error 76, "Invalid path: '" & strWhere & "'"
stack = strWhere & NL & stack ' "push" onto stack to retry later.
strWhere = fpath ' try a path one step shorter.
Resume failed
End Sub
' ===== Private Supporting Functions =====
Private Sub SplitFilePath(Byval fullpath$, dirpath$, filename$)
' *** This subroutine by Andre Guirard @ IBM
' *** http://planetlotus.org/profiles/andre-guirard_22584
' *** Called from MakeDir()
Const DELIMS = {/\:}
While Instr(DELIMS, Right$(fullPath, 1)) ' discard final delimiter character...
fullpath = Left$(fullpath, Len(fullpath)-1)
Wend
Dim candidate$, i%
filename = Strtoken(fullpath, Left$(DELIMS, 1), -1)
For i = 2 To Len(DELIMS)
candidate = Strtoken(fullpath, Mid$(DELIMS, i, 1), -1)
If Len(candidate) < Len(filename) Then
filename = candidate
End If
Next
Dim fplen%
fplen = Len(fullpath)-Len(filename)
If fplen > 0 Then fplen = fplen - 1
dirpath = Left$(fullpath, fplen)
End Sub
End Class

After posting this code, I got inspired to improve it, something I actually need for an upcoming project. I hope to post the new code shortly.