=begin

  GPG decryption script

  Requires a running GPGServer and uses another (proprietary protocol 

  addon to ESMPT for declaring source and target file for decryption. 

  This allows to reuse passphrase and GPG/MIME implementation which is 

  already implemented for the GPGServer

  (C) 2009, GNU General Public Licence, Author: Otto Linnemann

=end

# ------------- Main script  ------------- 

# Invocation: ruby gpg_smtp_decrypt encrypted_source_file decrypted_target_file [configfile]

# Read configuration file 

require 'socket'

require 'plist_parser'

LINESEP = "\r\n"

result = 0

if ARGV[3] == nil

  # in case no config file is given use default (here for MacOS X)

  configfilename = File.join( ENV["HOME"], "/Library/Preferences/GpgServer.plist" )

else

  configfilename = ARGV[3]

end

xml = ""

File.open( configfilename, "r") { |stream| xml = stream.read}

config  = PropertyParser.new.parse( xml )

extSmtp=config[0]["External SMTP"]

local=config[0]["Local SMTP"]

server_port = local["Port"]

begin

  # connect to server

  s = TCPSocket.open( "localhost", server_port )

rescue 

  STDERR.puts "GPGServer not running or couldn't connect!"

  exit -1

end

begin

  # reads server greeting message

  msg = s.gets 

  puts msg

  raise "Connection error" if !msg.match("GPG SMTP")

  # writes decode command to server 

  s.write "gpgdecode" + LINESEP

  # read ack from server

  msg = s.gets 

  puts msg

  # write source and target file to server

  s.write '"'+ARGV[0] +'" "' + ARGV[1] + '"' + LINESEP

  # read status from server

  msg = s.gets

  puts msg

  raise "GPG error: " + msg if !msg.match("250 Decryption: OK")

rescue => exception

  STDERR.puts "Decode error occured: "+exception.to_s

  result = -1

ensure

  # write quit to server

  s.write "QUIT" + LINESEP

  s.close

  exit result

end

__END__