Character encoding with Ruby 1.9.3 and the mail gem - ruby

Question

I'm trying to parse email strings with the Ruby mail gem, and I'm having a devil of a time with character encodings. Take the following email:
MIME-Version: 1.0
Sender: foobar#example.com
Received: by 10.142.239.17 with HTTP; Thu, 14 Jun 2012 06:00:18 -0700 (PDT)
Date: Thu, 14 Jun 2012 09:00:18 -0400
Delivered-To: foobar#gmail.com
X-Google-Sender-Auth: MxfFrMybNjBoBt4O4GwAn9cMsko
Message-ID: <CAGErOzF3FV5NvzN3zUpLGPok96SFzK18Z4HerzyYNALnzgMVaA#mail.gmail.com>
Subject: Re: [Lorem Ipsum] Foo updated the forum topic 'Reply by email test'
From: Foo Bar <foo#example.com>
To: Foo <c49964d167e08e7d4a1930e6565f23c258be19a0#foo.example.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
This email has accents:=A0R=E9sum=E9
>
> --------- Reply Above This Line ------------
>
> Email parsing with accents: R=E9sum=E9
>
> Click here to view this post in your browser
The email body, when properly encoded, should be:
This reply has accents: Résumé
>
> --------- Reply Above This Line ------------
>
> Email parsing with accents: Résumé
>
> Click here to view this post in your browser
However, I'm having a devil of a time actually getting the accent marks to come through. Here's what I've tried:
message = Mail.new(email_string)
body = message.body.decoded
That gets me a string that starts like this:
This reply has accents:\xA0R\xE9sum\xE9\r\n>\r\n> --------- Reply Above This Line ------------
Finally, I try this:
body.encoding # => <Encoding:ASCII-8BIT>
body.encode("UTF-8") # => Encoding::UndefinedConversionError: "\xA0" from ASCII-8BIT to UTF-8
Does anyone have any suggestions on how to deal with this? I'm pretty sure it has to do with the "charset=ISO-8859-1" setting in the email, but I'm not sure how to use that, or if there's a way to easily extract that using the mail gem.

Answer 1

After playing a bit, I found this:
body.decoded.force_encoding("ISO-8859-1").encode("UTF-8") # => "This reply has accents: Résumé..."
message.parts.map { |part| part.decoded.force_encoding("ISO-8859-1").encode(part.charset) } # multi-part
You can extract the charset from the message like so.
message.charset #=> for simple, non-multipart
message.parts.map { |part| part.charset } #=> for multipart, each part can have its own charset
Be careful with non-multipart, as the following can cause trouble:
body.charset #=> returns "US-ASCII" which is WRONG!
body.force_encoding(body.charset).encode("UTF-8") #=> Conversion error...
body.force_encoding(message.charset).encode("UTF-8") #=> Correct conversion :)

Answer 2

This didn't work for me, so thought I'd stick up the solution I got to in case it helps anyone...
Basically had to add encoding defaults and tweak the output into sensible strings.
https://stackoverflow.com/a/26604049/2386548