27.1.3 I18n from HTTP header ¶

(get "/index"
  #:i18n 'header
  (lambda (rc) ...))

• The language set in the HTTP header is "Accept-Language".
• If there’s multiple languages, GNU Artanis will choose the first one.
• Note that the language is in the format of RFC 4646 (e.g. ja-JP) GNU Artanis will convert it to the format of GNU Gettext (e.g. ja_JP).