How to get list of installed applications using Ru

问题:

I know that using wmi query WIN32_product one can read the list of installed applications but the list is different from add/remove program list under control panel. Another approach would be to read Software\Microsoft\Windows\CurrentVersion\Uninstall in windows registry?

I am using the following few lines of ruby code to do that but it is not working

For this example I am looking for a software by the name of Branding (it shows when I go thru regedit in my windows 7 PC)

Win32::Registry::HKEY_LOCAL_MACHINE.open('Software\Microsoft\Windows\CurrentVersion\Uninstall\Branding') do |reg|
  reg_typ, reg_val = reg.read('')
  return reg_val
end

Error Message after running this piece of code

win32/registry.rb:528:in `open': The system cannot find
the file specified. (Win32::Registry::Error)
        from win32/registry.rb:608:in `open'

What is wrong with this piece of code?

回答1:

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

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

Though beware of: 'Software\Wow6432Node\Windows\CurrentVersion\Uninstall'

回答2:

key = 'Software\Microsoft\Windows\CurrentVersion\Uninstall'
reg_type = Win32::Registry::Constants::KEY_READ | Windows::Registry::KEY_WOW64_64KEY

Win32::Registry.open(Win32::Registry::HKEY_LOCAL_MACHINE,key,reg_type) do |reg|
 reg.each_key do |key|
     k = reg.open(key)

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

Check out this link for an explanation of how the registry works on 64 bit platforms