Hi,
I’m in the process of transferring a bunch of script from powershell to
ruby to aid interoperability with an existing application and I’m
looking for two ruby equivalents to powershell commands:
PSBASE is a view which returns the raw view of an object.
getText returns the text between the current location and the specified
location in the buffer.
I use these a lot with WMI code in powershell, an example:
$Var1 = path to WMI class or object
$Var1.psbase.gettext(1) > wmi.xml
This would give me pure XML of a WMI object.
Any help greatly appreciated.
On Thu, Jun 19, 2008 at 10:38 AM, Nicholas C.
[email protected] wrote:
I use these a lot with WMI code in powershell, an example:
$Var1 = path to WMI class or object
$Var1.psbase.gettext(1) > wmi.xml
This would give me pure XML of a WMI object.
I’m not sure that you need PSBASE outside of powershell, I could be
wrong, though. GetText in OLE land is called GetText_.
Win32OLE example:
require ‘win32ole’
=> true
?> wmi = WIN32OLE.connect(“winmgmts://”)
=> #WIN32OLE:0x2c50740
?> processes = wmi.ExecQuery(“select * from win32_process”)
=> #WIN32OLE:0x2c280c0
?>
?> for process in processes do
?> p process.gettext_(1)
break
end
"<INSTANCE CLASSNAME="Win32_Process"><PROPERTY NAME="_PATH"
CLASSORIGIN="
…
Ruby-WMI example:
require ‘ruby-wmi’
=> true
proc = WMI::Win32_Process.find(:first)
=> #WIN32OLE:0x2be25e0
proc.gettext_(1)
=> “<PROPERTY NAME=”__PATH"
CLASSORIGIN="
…
Hope that helps.
Gordon
Cheers Gordon, you are a life saver. Whilst im on the same subject, i am
also having trouble creating a new GUID. With Powershell i can do:
$NEWGUID = [GUID]::NewGUID().ToString()
Do you think its possible to do this with Ruby and ruby-wmi?
Many thanks,
Nick
Gordon T. wrote:
On Thu, Jun 19, 2008 at 10:38 AM, Nicholas C.
[email protected] wrote:
I use these a lot with WMI code in powershell, an example:
$Var1 = path to WMI class or object
$Var1.psbase.gettext(1) > wmi.xml
This would give me pure XML of a WMI object.
I’m not sure that you need PSBASE outside of powershell, I could be
wrong, though. GetText in OLE land is called GetText_.
Win32OLE example:
require ‘win32ole’
=> true
?> wmi = WIN32OLE.connect(“winmgmts://”)
=> #WIN32OLE:0x2c50740
?> processes = wmi.ExecQuery(“select * from win32_process”)
=> #WIN32OLE:0x2c280c0
?>
?> for process in processes do
?> p process.gettext_(1)
break
end
"<INSTANCE CLASSNAME="Win32_Process"><PROPERTY NAME="_PATH"
CLASSORIGIN="
…
Ruby-WMI example:
require ‘ruby-wmi’
=> true
proc = WMI::Win32_Process.find(:first)
=> #WIN32OLE:0x2be25e0
proc.gettext_(1)
=> “<PROPERTY NAME=”__PATH"
CLASSORIGIN="
…
Hope that helps.
Gordon
On Fri, Jun 20, 2008 at 14:21, Nicholas C. [email protected]
wrote:
Cheers Gordon, you are a life saver. Whilst im on the same subject, i am
also having trouble creating a new GUID. With Powershell i can do:
$NEWGUID = [GUID]::NewGUID().ToString()
Do you think its possible to do this with Ruby and ruby-wmi?
This is how I create GUIDs (requires win32utils gem, might not be
tested - I’m reinstalling ruby right now):
require ‘windows/com’
require ‘windows/unicode’
class String
Return the portion of the string up to the first NULL character.
This
was added for both speed and convenience.
def nstrip
self[ /^[^\0]*/ ]
end
end
class Guid
BUFFER_SIZE = 100
attr_reader :data
def initialize(data = nil)
@data = data
create if data.nil?
end
def create
@data = 0.chr * 16
raise ‘GUID Error’ unless CoCreateGuid(@data)
end
def to_s
ret = 0.chr * BUFFER_SIZE
i = StringFromGUID2(@data, ret, BUFFER_SIZE)
wide_to_multi(ret[0…i*2]).nstrip
end
private
include Windows::COM
include Windows::Unicode
end
if File.expand_path(FILE) == File.expand_path($0)
puts Guid.new.to_s
end
Thanks Jano. If you have a minute, do you think you could run through
that code and explain what its doing? I am new to Ruby and a large
portion of that went over my head 
Nick
On Fri, Jun 20, 2008 at 16:05, Nicholas C. [email protected]
wrote:
Thanks Jano. If you have a minute, do you think you could run through
that code and explain what its doing? I am new to Ruby and a large
portion of that went over my head 
-
You’ll find documentation for CoCreateGuid here:
CoCreateGuid function (combaseapi.h) - Win32 apps | Microsoft Learn
and for StringFromGUID2 here:
StringFromGUID2 function (combaseapi.h) - Win32 apps | Microsoft Learn
(these are C functions from ole32.dll)
-
I call them using WIN32API, conveniently wrapped by windows-pr gem
from win32utils project.
these are from windows-pr gem
require ‘windows/com’
require ‘windows/unicode’
helper function to strip everything past the first NULL character.
Copied from some file in win32utils
class String
Return the portion of the string up to the first NULL character.
This
was added for both speed and convenience.
def nstrip
self[ /^[^\0]*/ ]
end
end
class Guid
BUFFER_SIZE = 100
attr_reader :data
two ways of using this class - 1. either provide GUID in binary
form Guid.new(data) or create a new one (Guid.new)
def initialize(data = nil) ### nil is default value for data parameter
@data = data
create if data.nil? ### if there’s no data, call create
end
create new guid
def create
@data = 0.chr * 16 ### make empty buffer for the binary GUID
“\0\0\0\0…\0”
raise ‘GUID Error’ unless CoCreateGuid(@data) ### call the API. the
call will place the created GUID in @data.
end
convert binary guid to string representation
def to_s
ret = 0.chr * BUFFER_SIZE ### temporary buffer to place the string
form
i = StringFromGUID2(@data, ret, BUFFER_SIZE) ### call the API
API returns zero-terminated wide string. this is the conversion to
ordinary ruby string.
wide_to_multi is from windows/unicode
wide_to_multi(ret[0…i*2]).nstrip
end
private
this code includes COM and Unicode modules into this class, so
that we can use them.
include Windows::COM
include Windows::Unicode
end
this line is kind of idiom/guard
it allows to specify code to be run when the file is run directly.
This code will not run
if this file is required or included in another file. (script vs.
library)
if File.expand_path(FILE) == File.expand_path($0)
puts Guid.new.to_s
end
Ok, and now ask questions! 
J.