From: Masaki Suketa <masaki.suketa@...>
Date: 2005-04-04T21:23:31+09:00
Subject: Re: win32ole not all methods work

Hello,

In message "win32ole not all methods work"
    on 05/04/02, BG - Ben Armstrong <BArmstrong@dymaxion.ca> writes:

> Can someone explain what's going on here, and if there is a fix?  Looks
> like certain methods don't work, maybe because the type of object
> returned isn't known.
> 
> WIN32OLE.new('Scripting.FileSystemObject').Drives.each{|drive|
>     p [drive.driveLetter,drive.driveType,drive.shareName,drive.isReady,drive.path,drive.serialNumber]}
> 
> # Generates:
> #
> # C:/Work/diskid.rb:4:in `method_missing': serialNumber (WIN32OLERuntimeError)
> #     OLE error code:800A0047 in <Unknown>
> #       <No Description>
> #     HRESULT error code:0x80020009
> #       Exception occurred        from C:/Work/diskid.rb:4
> #         from C:/Work/diskid.rb:3:in `each'
> #         from C:/Work/diskid.rb:3
> #

It seems to me the correct behavier.

The following VBScript returns the runtime exception.

  Dim fso
  Set fso = CreateObject("Scripting.FileSystemObject")
  For each drive in fso.Drives
      WScript.Stdout.WriteLine drive.driveLetter
      WScript.Stdout.WriteLine drive.driveLetter
      WScript.Stdout.WriteLine drive.driveType
      WScript.Stdout.WriteLine drive.shareName
      WScript.Stdout.WriteLine drive.isReady
      WScript.Stdout.WriteLine drive.path
      ' The following line returns the runtime exception.
      WScript.Stdout.WriteLine drive.serialNumber
  Next

I think drive.isReady is false then, drive.serialNumber raise runtime 
exception in VBScript.
And If, the VBScript raise the runtime exception, the Ruby script raise the
runtime exception in the similarly.
So, the following Ruby script as same as above sample,
raise Exception in drive.serialNumber.

  require 'win32ole'
  WIN32OLE.new('Scripting.FileSystemObject').Drives.each{|drive|
    p drive.driveLetter
    p drive.driveType
    p drive.shareName
    p drive.isReady
    p drive.path
    p drive.serialNumber # occur Exception if drive.isReady is false.
  }

In my environment, if the drive is floppy drive or CDROM drive, then
occur the exception.

So, 
> # C:/Work/diskid.rb:4:in `method_missing': serialNumber (WIN32OLERuntimeError)
(snip)
> #       Exception occurred        from C:/Work/diskid.rb:4
is correct behavior.

  Regards,
  Masaki Suketa