From: Daiki Ueno <ueno@...>
Date: 2010-01-17T21:59:48+09:00
Subject: Re: GPGME gem - cannot figure out how to decrypt data

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Daniel Frank <ruby-talk-2597@danielfrank.net> writes:

>> Could you provide actual input args to passfunc, that can be inspected
>> with:
>>
> def passfunc(*args)
>         p args
>         puts "Passphrase callback"
>         SMGConfig.instance.gpg_password
> end
>
> Relevant part of the output:
> decrypting
> []
> Passphrase callback
>
> If I interpret this right, [] means that there's an empty array, which
> means no arguments?

You are right, but the result looks strange.  Could you try the attached
script, which decrypts a file specified as the first command line
argument?  I've confirmed it working with gpgme-1.0.8 (gem), ruby-1.8.7,
and gpg 1.4.10, as follows:

$ echo this is a test | gpg --encrypt -r 37ED8A79 > test.gpg
$ ruby1.8 -rubygems decrypt.rb test.gpg
Plaintext:
this is a test


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Content-Type: application/x-ruby
Content-Disposition: attachment; filename=decrypt.rb

#!/usr/bin/env ruby
require 'gpgme'

# If you do not have gpg-agent installed, comment out the following
# and set it as :passphrase_callback.
#
def passfunc(hook, uid_hint, passphrase_info, prev_was_bad, fd)
  $stderr.write("Passphrase for #{uid_hint}: ")
  $stderr.flush
  begin
    system('stty -echo')
    io = IO.for_fd(fd, 'w')
    io.puts(gets)
    io.flush
  ensure
    (0 ... $_.length).each do |i| $_[i] = ?0 end if $_
    system('stty echo')
  end
  $stderr.puts
end

unless ENV['GPG_AGENT_INFO']
  $stderr.puts("gpg-agent is not running.  See the comment in #{$0}.")
  exit(1)
end

plain = GPGME::decrypt(ARGF, {
			 :passphrase_callback => method(:passfunc)
		       })
puts("Plaintext:\n#{plain}")

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Regards,
-- 
Daiki Ueno

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