# Win32ole - windowsinstaller.installer method

**URL:** <https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644>\
**Category:** Ruby\
**Created:** [July 24, 2009, 1:56pm UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644 "2009-07-24T13:56:11Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![mickesommar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/c5a1d2/32.png) [@mickesommar](https://www.ruby-forum.com/u/mickesommar)\
**Post date:** [July 24, 2009, 1:56pm UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644/1 "2009-07-24T13:56:11Z")

</div>

Hi all

I’m a beginner at ruby, so correct me if I’m doing something stupid.

I have created a method that reads a property from a windowsinstaller  
table. (msi-package).

I have a list with paths to msi-packages, its 238 msi-packages that I’m  
searching throe.  
If i searching all the 238 files it eats a lot of memory (240 mb). And  
21 packages fails to be read.  
If i split the list in two it work without any problem, all the files  
works.

I wonder if i have write my method in a bad way.

Any ideas ?

Method:

def GetProperty(msiPath, property)  
begin  
require ‘win32ole’  
msiInstaller = WIN32OLE.new(‘WindowsInstaller.Installer’)  
db = msiInstaller.OpenDatabase(msiPath, 0)  
view = db.OpenView(“SELECT Value FROM Property WHERE Property =  
‘#{property}’”)  
view.Execute()  
rescue RuntimeError  
return “ERROR”  
end  
record = view.Fetch()  
if record != nil then  
return record.StringData(1)  
else  
return 0  
end  
end

GetProperty("\path\to\msi\package.msi", “ALLUSERS”)

If the property don’t exist it return 0, if the msi-package don’t exist  
it return error, or if any other error message appear. If everything  
work it return the value of ALLUSERS in the property-table of the  
msi-packge.

If i inactivate the method the script doesn’t use so much memory.

// Micke

---

<div class="post-metadata">

**Author:** ![mickesommar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/c5a1d2/32.png) [@mickesommar](https://www.ruby-forum.com/u/mickesommar)\
**Post date:** [July 24, 2009, 6:17pm UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644/2 "2009-07-24T18:17:13Z")

</div>

Hello,

Micke M. wrote:

> ```
> msiInstaller = WIN32OLE.new('WindowsInstaller.Installer')
> else
> return 0
> end
> 
> ```
> 
> end

I have not written script using WindowsInstaller, but I think:  
(1) msiInstaller should be created only at once if you could.  
(2) view.close() should be called before return from GetProperty.  
(I can’t find how to close db(Database) object.)

(1)  
require ‘win32ole’  
class Installer  
@@msiInstaller = nil  
def self.create  
if !@@msiInstaller  
@@msiInstaller = WIN32OLE.new(‘WindowsInstaller.Installer’)  
end  
@@msiInstaller  
end  
end

def GetProperty(msiPath, property)  
begin  
msiInstaller = Installer.create  
…  
(2)  
record = view.Fetch()  
val = 0  
if record != nil then  
val = record.StringData(1)  
else  
val = 0  
end  
view.close  
return val

Hope this helps.  
Regards,  
Masaki S.

---

<div class="post-metadata">

**Author:** ![mickesommar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/c5a1d2/32.png) [@mickesommar](https://www.ruby-forum.com/u/mickesommar)\
**Post date:** [July 28, 2009, 9:53am UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644/3 "2009-07-28T09:53:48Z")

</div>

Masaki S. wrote:

> Hello,
> 
> Micke M. wrote:
> 
> > ```
> > msiInstaller = WIN32OLE.new('WindowsInstaller.Installer')
> > else
> > return 0
> > end
> > 
> > ```
> > 
> > end
> 
> I have not written script using WindowsInstaller, but I think:  
> (1) msiInstaller should be created only at once if you could.  
> (2) view.close() should be called before return from GetProperty.  
> (I can’t find how to close db(Database) object.)
> 
> (1)  
> require ‘win32ole’  
> class Installer  
> @@msiInstaller = nil  
> def self.create  
> if !@@msiInstaller  
> @@msiInstaller = WIN32OLE.new(‘WindowsInstaller.Installer’)  
> end  
> @@msiInstaller  
> end  
> end
> 
> def GetProperty(msiPath, property)  
> begin  
> msiInstaller = Installer.create  
> …  
> (2)  
> record = view.Fetch()  
> val = 0  
> if record != nil then  
> val = record.StringData(1)  
> else  
> val = 0  
> end  
> view.close  
> return val
> 
> Hope this helps.  
> Regards,  
> Masaki S.

Hi Masaki

I have tried the example above, unfortunately i get same result as  
before. The script eats allot of memory, and it will not receive all the  
msi-package information.

As i mention before, if I divide the msi-package-list in to, run the  
script to time, it works.

I have tried with the latest version of ruby, but it fails, this time it  
fails with more packages compare to 1.8 release of ruby.  
I also tried to cut up the list in two arrays, and execute the  
msi-method two times, but i get same problem as above.

I tried to make a similar script in python, except i can’t apply  
transform-files, it worked without any problem, and much less memory  
usage.  
So i wonder if it is a problem in the win32ole.

Thanks for you help.

// Micke

---

<div class="post-metadata">

**Author:** ![mickesommar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/c5a1d2/32.png) [@mickesommar](https://www.ruby-forum.com/u/mickesommar)\
**Post date:** [July 28, 2009, 12:03pm UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644/4 "2009-07-28T12:03:43Z")

</div>

Hello,

Micke M. wrote:

> I also tried to cut up the list in two arrays, and execute the  
> msi-method two times, but i get same problem as above.

How about calling GC.start in GetProperty method?

def GetProperty(msiPath, property)  
GC.start # \<- add this line  
begin  
msiInstaller = Installer.create

Regards,  
Masaki S.

---

<div class="post-metadata">

**Author:** ![mickesommar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/c5a1d2/32.png) [@mickesommar](https://www.ruby-forum.com/u/mickesommar)\
**Post date:** [July 28, 2009, 3:42pm UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644/5 "2009-07-28T15:42:38Z")

</div>

Hello,

At 07/28/2009 07:54 PM, Micke M. wrote:

> Do you know any good article how to structure ruby-programs ?

Sorry, I don’t know English article about Win32OLE.  
(but someone in this ML knows it…)

The articles written in Japanese are:  
[http://jp.rubyist.net/magazine/?0003-Win32OLE](http://jp.rubyist.net/magazine/?0003-Win32OLE)  
[http://www.morijp.com/masarl/homepage3.nifty.com/masarl/article/ruby-win32ole.html](http://www.morijp.com/masarl/homepage3.nifty.com/masarl/article/ruby-win32ole.html)

Regards,  
Masaki S.

---

<div class="post-metadata">

**Author:** ![mickesommar](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/c5a1d2/32.png) [@mickesommar](https://www.ruby-forum.com/u/mickesommar)\
**Post date:** [July 28, 2009, 12:54pm UTC](https://www.ruby-forum.com/t/win32ole-windowsinstaller-installer-method/172644/6 "2009-07-28T12:54:46Z")

</div>

Masaki S. wrote:

> Hello,
> 
> Micke M. wrote:
> 
> > I also tried to cut up the list in two arrays, and execute the  
> > msi-method two times, but i get same problem as above.
> 
> How about calling GC.start in GetProperty method?
> 
> def GetProperty(msiPath, property)  
> GC.start # \<- add this line  
> begin  
> msiInstaller = Installer.create
> 
> Regards,  
> Masaki S.

Hi Masaki

A big thanks fore you help, the GC.start solved the problem.

Do you know any good article how to structure ruby-programs ?

// Micke