utilities for getting microsoft installer product code data from ruby

check_installed.rb

# Reads a product code from an MSI file
# Checks if that product code is installed on the system

require 'rubygems'
require 'ffi'
require 'pathname'

PRODUCT_CODE_LENGTH = 38

module Win32
  extend FFI::Library
  ffi_lib 'msi'
  
  attach_function :msi_open_package, :MsiOpenPackageExA, [ :string, :int, :pointer ], :int
  attach_function :msi_get_product_property, :MsiGetProductPropertyA, [ :pointer, :pointer, :pointer, :pointer ], :int
  attach_function :msi_get_product_info, :MsiGetProductInfoA, [ :pointer, :pointer, :pointer, :pointer ], :int
  attach_function :msi_close_handle, :MsiCloseHandle, [ :pointer ], :int
end

def print_usage
  puts "Checks if a provided Microsoft Installer Product is already installed"
  puts "Usage: ruby #{__FILE__} example.msi"
end

def get_product_code(package_path)
  product_code = 0.chr * (PRODUCT_CODE_LENGTH + 1)
  product_code_length = FFI::Buffer.new(:long).write_long(PRODUCT_CODE_LENGTH + 1)
  pkg_ptr = FFI::MemoryPointer.new(:pointer, 4)

  status = Win32.msi_open_package(package_path, 1, pkg_ptr)

  case status
  when 0
    # success
  when 1619
    raise "msi_open_package #{status}: ERROR_INSTALL_PACKAGE_OPEN_FAILED"
  else
    raise "msi_open_package returned #{status}"
  end

  status = Win32.msi_get_product_property(pkg_ptr.read_pointer, "ProductCode", product_code, product_code_length)

  raise "Unexpected status #{status}" unless status == 0

  Win32.msi_close_handle(pkg_ptr)

  product_code
end

def product_installed?(product_code)
  #UINT MsiGetProductInfo(
  #  _In_     LPCTSTR szProduct,
  #  _In_     LPCTSTR szProperty,
  #  _Out_    LPTSTR lpValueBuf,
  #  _Inout_  DWORD *pcchValueBuf
  #);
  buffer = 0.chr
  buffer_length = FFI::Buffer.new(:long).write_long(0)

  status = Win32.msi_get_product_info(product_code, "VersionString", buffer, buffer_length)
  
  return false if status == 1605 # ERROR_UNKNOWN_PRODUCT (0x645)

  if ( status != 234 )
    raise "Unexpected status #{status}"
  end

  buffer_length = FFI::Buffer.new(:long).write_long(buffer_length.read_long + 1)
  buffer = 0.chr * buffer_length.read_long

  status = Win32.msi_get_product_info(product_code, "VersionString", buffer, buffer_length)

  raise "msi_get_product_info: unexpected status: #{status}" if status != 0

  true
end

if ARGV.length < 1
  print_usage
  exit 1
end

# MsiOpenPackage expects a perfect absolute Windows path to the MSI
package_path = Pathname.new(ARGV[0]).realpath.to_s.gsub(/\//, '\\')

pc = get_product_code(package_path)
puts "Product Code: #{pc}"

puts "Installed?: #{product_installed?(pc)}"

product_code.rb

# opens an msi file and gets the ProductCode
require 'rubygems'
require 'ffi'
require 'pathname'

module Win32
  extend FFI::Library
  ffi_lib 'msi'
  
  attach_function :msi_open_package, :MsiOpenPackageExA, [ :string, :int, :pointer ], :int
  attach_function :msi_get_product_property, :MsiGetProductPropertyA, [ :pointer, :pointer, :pointer, :pointer ], :int
  attach_function :msi_close_handle, :MsiCloseHandle, [ :pointer ], :int
end

def print_usage
  puts "Checks if a provided Microsoft Installer Product is already installed"
  puts "Usage: ruby #{__FILE__} example.msi"
end

def get_product_code(package_path)
  product_code = 0.chr
  product_code_length = FFI::Buffer.new(:long).write_long(0)
  pkg_ptr = FFI::MemoryPointer.new(:pointer, 4)

  puts "Opening package: #{package_path}"

  status = Win32.msi_open_package(package_path, 1, pkg_ptr)
  
  case status
  when 0
    # success
  when 1619
    raise "msi_open_package #{status}: ERROR_INSTALL_PACKAGE_OPEN_FAILED"
  else
    raise "msi_open_package returned #{status}"
  end
  
  status = Win32.msi_get_product_property(pkg_ptr.read_pointer, "ProductCode", product_code, product_code_length)

  if ( status != 234 )
    raise "Unexpected status #{status}"
  end

  product_code_length = FFI::Buffer.new(:long).write_long(product_code_length.read_long + 1)

  product_code = 0.chr * product_code_length.read_long
  
  status = Win32.msi_get_product_property(pkg_ptr.read_pointer, "ProductCode", product_code, product_code_length)

  raise "msi_get_product_property: #{status}" unless status == 0

  Win32.msi_close_handle(pkg_ptr)

  product_code
end

if ARGV.length < 1
  print_usage
  exit 1
end

# MsiOpenPackage expects a perfect absolute Windows path to the MSI
package_path = Pathname.new(ARGV[0]).realpath.to_s.gsub(/\//, '\\')

puts get_product_code(package_path)