Query installed software on windows with ruby

I want to query all of the installed software on a windows machine. I found another post that was doing something similar here.

I modified the code slight开发者_StackOverflow社区ly:

require 'win32/registry'

Win32::Registry::HKEY_LOCAL_MACHINE.open('Software\Microsoft\Windows\CurrentVersion\Uninstall') do |reg|
    reg.each_key do |key1,key2|
        k = reg.open(key1)

        puts k["DisplayName"]    rescue "?"
        puts k["DisplayVersion"] rescue "?"
        puts k["Publisher"]      rescue "?"
        puts k["URLInfoAbout"]   rescue "?"
        puts
    end
end

This gets me some information, but I'd like to obtain other information about the software. For example, it'd be great to have an installation date, license information, etc.

I'm very new to ruby. How do I know what the indices or keys into k are? Obviously, "DisplayName" is one, but how do I find others? Is there a better way to go about getting this information programmatically?

---

If you just want to know complete information about the software, you can use this:

require 'win32/registry'
require 'pp' # for pretty print

Win32::Registry::HKEY_LOCAL_MACHINE.open('Software\Microsoft\Windows\CurrentVersion\Uninstall') do |reg|
    reg.each_key do |key1,key2|
        k = reg.open(key1)
        pp k.inject([]) {|info, data| info << data}
    end
end

And you'll get something like this:

 ["UninstallString",
  1,
  "\"C:\\WINDOWS\\$NtUninstallKB2393802$\\spuninst\\spuninst.exe\""],
 ["TSAware", 4, 1],
 ["NoModify", 4, 1],
 ["InstallDate", 1, "20110313"],
 ["Publisher", 1, "Microsoft Corporation"],
 ["NoRepair", 4, 1],
 ["HelpLink", 1, "http://support.microsoft.com?kbid=2393802"],
 ["URLInfoAbout", 1, "http://support.microsoft.com"],
 ["DisplayVersion", 1, "1"],
 ["ParentKeyName", 1, "OperatingSystem"],
 ["ParentDisplayName",

and so on.