ActionMailer and TMail need multilocalization in Ruby 1.9 so that a Rails application send a mail with a correct encoding.

Status

Japanese texts

ActionMailer always sends an email in UTF-8. According to RFC 1468, however, Japanese email should be encoded in ISO-2022-JP. The RFC is just a guide, not a standard. But most of MUA prefer ISO-2022-JP to UTF-8 for Japanese. Japanese mobile phones can send/receive internet emails but most of them accept only ISO-2022-JP.

So TMail can treat Japanese texts specially.

• http://github.com/rails/rails/blob/master/actionmailer/lib/action_m...

But ActionMailer does not use this capability. So Japanese developers use some monkey patches.
This is an implementation in Ruby-GetText-Package.

• http://github.com/mutoh/gettext_rails/blob/master/lib/gettext_rails...

Other locales

Now we can support other locales with Ruby 1.9.

TMail and Ruby-GetText-Package treats Japanese text specially. I think this is because

• Ancient versions of Ruby did not have Iconv,
• Iconv is too platform-depended,
• NKF and Kconv only supports Japanese,
• Both of the original developers of the libraries are Japanese.

According to RFC 1557, Korean emails should be encoded in ISO-2022-KR.

I don't know enough about custom in other locales like Chinese/Vietnamese/Arabic. But Maybe this kind of problem can occur in these locales.

TODO

• ActionMailer should have capability to send an email in other encodings.
  • with String#encode in Ruby 1.9.
• Default mapping from language to preferred encoding so that a programmer assign a suitable encoding to an email by locale name.
  • Suitable encoding is not unique for a language. Japanese mobile phones which Softbank provides prefer UTF-8.
• TMail might need some fixes.
• Advices by Chinese/Vietnamese/Arabic/.... developers are necessary.