RFC 3282

RFC 3282

Network Working Group H. Alvestrand Request for Comments: 3282 Cisco Systems Obsoletes: 1766 May 2002 Category: Standards Track

  <!ENTITY ja.mail.header "頭">
                       Content Language Headers

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.


   This document defines a "Content-language:" header, for use in cases
   where one desires to indicate the language of something that has RFC
   822-like headers, like MIME body parts or Web documents, and an
   "Accept-Language:" header for use in cases where one wishes to
   indicate one's preferences with regard to language.
  <!ENTITY ja.mime.body-part "本文部分">
この文書は "Content-language:" &ja.mail.header;を MIME &ja.mime.body-part;や
Web 文書のような RFC 822 的&ja.mail.header;を持つものの言語を示したい場合に使うのに、また
"Accept-Language:" &ja.mail.header;を言語に関する好みを示したいと願う場合に使うのに定義します。

1. Introduction

   There are a number of languages presently or previously used by human
   beings in this world.
   A great number of these people would prefer to have information
   presented in a language which they understand.
   In some contexts, it is possible to have information available in
   more than one language, or it might be possible to provide tools
   (such as dictionaries) to assist in the understanding of a language.
(例えば辞書) を提供することが可能であったりするかもしれません。
   In other cases, it may be desirable to use a computer program to
   convert information from one format (such as plaintext) into another
   (such as computer-synthesized speech, or Braille, or high-quality
   print renderings).
  <!ENTITY ja.plain-text "平文">
  <!ENTITY ja.rendering "レンダリング">
この他、計算機プログラムを、ある形式 (例えば&ja.plain-text;)
から他の形式 (計算機合成話, 点字, 高品質印刷&ja.rendering;など)
   A prerequisite for any such function is a means of labelling the
   information content with an identifier for the language that is used
   in this information content, such as is defined by [TAGS].  This
   document specifies a protocol element for use with protocols that use
   RFC 822-like headers for carrying language tags as defined in [TAGS].

このような機能には、その情報内容中で使われている言語の, [TAGS] で定義されているような識別子で情報内容を札付けする必要があります。この文書は、 RFC 822 的&ja.mail.header;を使う&ja.protocol;で [TAGS] で定義された言語札を運ぶ&ja.protocol;要素を規定します。

  <!ENTITY ja.protocol "プロトコル">

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC 2119].

この文書中で、用語 は で説明されているように解釈するものとします。

2. The Content-language header

   The "Content-Language" header is intended for use in the case where
   one desires to indicate the language(s) of something that has RFC
   822-like headers, such as MIME body parts or Web documents.

"Content-Language" &ja.mail.header;は、 MIME &ja.mime.body-part;や Web 文書のように、 RFC 822 的&ja.mail.header;を持つものの言語を示したい時に使うことを意図しています。

   The RFC 822 EBNF of the Content-Language header is:
Content-Language &ja.mail.header;の RFC 822 EBNF は次の通りです。
      Content-Language = "Content-Language" ":" 1#Language-tag
   In the more strict RFC 2234 ABNF:
より厳密な RFC 2234 ABNF では次の通りです。
      Content-Language = "Content-Language" ":" [CFWS] Language-List
      Language-List = Language-Tag [CFWS]
                         *("," [CFWS] Language-Tag [CFWS])
   The Content-Language header may list several languages in a comma-
   separated list.
Content-Language &ja.mail.header;では、読点 (comma)
   The CFWS construct is intended to function like the whitespace
   convention in RFC 822, which means also that one can place
   parenthesized comments anywhere in the language sequence, or use
   continuation lines.  A formal definition is given in RFC 2822
CFWS 構造は、 RFC 822 の&ja.whitespace;記法の様に機能することを想定しています。ですから括弧で括った注釈を言語列中のどこにでも置くことが出来ますし、継続行を使うことも出来ます。正式な定義は 
RFC 2822 中にあります。
   In keeping with the tradition of RFC 2822, a more liberal "obsolete"
   grammar is also given:
RFC 2822 の伝統を受け継ぎ、より寛大な「時代遅れ」文法も示します。
      obs-content-language = "Content-Language" *WSP ":"
                              [CFWS] Language-List
   Like RFC 2822, this specification says that conforming
   implementations MUST accept the obs-content-language syntax, but MUST
   NOT generate it; all generated headers MUST conform to the Content-
   Language syntax.

RFC 2822 同様、適合する実装は obs-content-language 構文を受け付け<ja:MUST>なければなりません</ja:MUST>が、生成<ja:MUSTNOT>してはならない</ja:MUSTNOT>ことをこの規定は示しています。生成する全ての&ja.mail.header;は、 Content-Language 構文に適合し<ja:MUST>なければなりません</ja:MUST>。

2.1 Examples of Content-language values Content-language 値の例

Voice recording from Liverpool downtown Liverpool 下町での音声録音

      Content-type: audio/basic
      Content-Language: en-scouse

Document in Mingo, an American Indian language which does not have an ISO 639 code: Mingo (亜米利加インディアン言語で、 ISO 639 &ja.lang.code;を持たない。) で書かれた文書

      Content-type: text/plain
      Content-Language: i-mingo

A English-French dictionary 英仏辞典

      Content-type: application/dictionary
      Content-Language: en, fr (This is a dictionary)

An official European Commission document (in a few of its official languages): 欧州委員会の公式文書 (その公用語の幾つかで)

      Content-type: multipart/alternative
      Content-Language: da, de, el, en, fr, it

An excerpt from Star Trek Star Trek からの抜粋

      Content-type: video/mpeg
      Content-Language: i-klingon

3. The Accept-Language header

   The "Accept-Language" header is intended for use in cases where a
   user or a process desires to identify the preferred language(s) when
   RFC 822-like headers, such as MIME body parts or Web documents, are
"Accept-Language" 頭は、MIME &ja.mime.body-part;や
Web 文書のような RFC 822 的&ja.mail.header;を持つもので、利用者や処理が、好ましい言語を示したい場合に使うことを意図しています。
   The RFC 822 EBNF of the Accept-Language header is:
Accept-Language &ja.header;の RFC 822 EBNF は次の通りです。
      Accept-Language = "Accept-Language" ":"
                             1#( language-range [ ";" "q" "=" qvalue ] )
   A slightly more restrictive RFC 2234 ABNF definition is:
より厳密な RFC 2234 ABNF の定義は次の通りです。
      Accept-Language = "Accept-Language:" [CFWS] language-q
                        *( "," [CFWS] language-q )
      language-q = language-range [";" [CFWS] "q=" qvalue ] [CFWS]
      qvalue         = ( "0" [ "." 0*3DIGIT ] )
                     / ( "1" [ "." 0*3("0") ] )
   A more liberal RFC 2234 ABNF definition is:
より寛大な RFC 2234 ABNF 定義は次の通りです。
      Obs-accept-language = "Accept-Language" *WSP ":" [CFWS]
           obs-language-q *( "," [CFWS] obs-language-q ) [CFWS]
      obs-language-q = language-range
            [ [CFWS] ";" [CFWS] "q" [CFWS] "=" qvalue ]
   Like RFC 2822, this specification says that conforming
   implementations MUST accept the obs-accept-language syntax, but MUST
   NOT generate it; all generated messages MUST conform to the Accept-
   Language syntax.
RFC 2822 同様、適合する実装は obs-accept-language
Accept-Language 構文に適合し<ja:MUST>なければなりません</ja:MUST>。
   The syntax and semantics of language-range is defined in [TAGS].  The
   Accept-Language header may list several language-ranges in a comma-
   separated list, and each may include a quality value Q.  If no Q
   values are given, the language-ranges are given in priority order,
   with the leftmost language-range being the most preferred language;
   this is an extension to the HTTP/1.1 rules, but matches current
language-range の構文と意味は [TAGS] で定義しています。
Accept-Language &ja.mail.header;は、読点 (comma)
で区切った一覧の形で複数の language-range を列挙しても構いません。それぞれは資質値
Q を含んでも構いません。 Q 値が与えられていない場合、
language-range は優先順に与えられ、一番左の language-range
が最優先の言語となります。これは HTTP/1.1 の規則の拡張ですが、現在の慣習と一致しています。
   If Q values are given, refer to HTTP/1.1 [RFC 2616] for the details
   on how to evaluate it.
Q 値が与えられている場合、どう評価するかの詳細については HTTP/1.1

4. Security Considerations

   The only security issue that has been raised with language tags since
   the publication of RFC 1766, which stated that "Security issues are
   believed to be irrelevant to this memo", is a concern with language
   ranges used in content negotiation - that they may be used to infer
   the nationality of the sender, and thus identify potential targets
   for surveillance.
  <!ENTITY ja.security "安全性">
  <!ENTITY ja.lang.tag "札">
  <!ENTITY ja.conneg "内容折衝">
RFC 1766 の出版以降言語&ja.lang.tag;に関して起こった唯一の&ja.security;問題は、&ja.conneg;において使われる言語範囲に関してです。これは送信者の民族を推察するのに使われ得るので、潜在的監視対象を特定することになり得ます。
   This is a special case of the general problem that anything you send
   is visible to the receiving party; it is useful to be aware that such
   concerns can exist in some cases.
   The exact magnitude of the threat, and any possible countermeasures,
   is left to each application protocol.
  <!ENTITY ja.application "応用">

5. Character set considerations

   This document adds no new considerations beyond what is mentioned in
この文書では TAGS で挙げたもの以外に追加の考慮事項はありません。

6. Acknowledgements

   This document has benefited from many rounds of review and comments
   in various fora of the IETF and the Internet working groups.
この文書は、 IETF と Internet 作業部会の各種討論場にでの多段階にわたる批評から利益を得ました。
   Any list of contributors is bound to be incomplete; please regard the
   following as only a selection from the group of people who have
   contributed to make this document what it is today.

In alphabetical order: 字母順

   Tim Berners-Lee, Nathaniel Borenstein, Sean M. Burke, John Clews, Jim
   Conklin, John Cowan, Dave Crocker, Martin Duerst, Michael Everson,
   Ned Freed, Tim Goodwin, Dirk-Willem van Gulik, Marion Gunn, Paul
   Hoffman, Olle Jarnefors, John Klensin, Bruce Lilly, Keith Moore,
   Chris Newman, Masataka Ohta, Keld Jorn Simonsen, Rhys Weatherley,
   Misha Wolf, Francois Yergeau and many, many others.
   Special thanks must go to Michael Everson, who has served as language
   tag reviewer for almost the entire period, since the publication of
   RFC 1766, and has provided a great deal of input to this revision.
   Bruce Lilly did a special job of reading and commenting on my ABNF
  <!ENTITY ja.ietf.reviewer "評論者">
  <!ENTITY ja.lang.code "符号">
Michael Everson には特に感謝しなければなりません。彼は、
RFC 1766 の出版からほとんど全期間&ja.lang.tag;&ja.ietf.reviewer;を務めて下さり、この改訂にも大変多くの意見を下さいました。
Bruce Lilly は、私の ABNF 定義を読んで評価するという特別な仕事をして下さいました。

7. References

   [TAGS]      Alvestrand, H., "Tags for the Identification of
               Languages", BCP 47, RFC 3066
   [ISO 639]   ISO 639:1988 (E/F) - Code for the representation of names
               of languages - The International Organization for
               Standardization, 1st edition, 1988-04-01 Prepared by
               ISO/TC 37 - Terminology (principles and coordination).
               Note that a new version (ISO 639-1:2000) is in
               preparation at the time of this writing.
用語 (原則及び調整)
<!-- <http://www.jisc.go.jp/international/iso-tc.html> -->
<!-- JIS にない?? -->
なお、執筆の時点で新版 (ISO 639-1:2000) が準備中。
   [ISO 639-2] ISO 639-2:1998 - Codes for the representation of names of
               languages -- Part 2: Alpha-3 code  - edition 1, 1998-11-
               01, 66 pages, prepared by ISO/TC 37/SC 2
   [ISO 3166]  ISO 3166:1988 (E/F) - Codes for the representation of
               names of countries - The International Organization for
               Standardization, 3rd edition, 1988-08-15.
<!-- JIS X 0304:1999 / ISO 3166-1:1997 -->
   [ISO 15924] ISO/DIS 15924 - Codes for the representation of names of
               scripts (under development by ISO TC46/SC2)
(ISO TC46/SC2 で開発中)
   [RFC 2045]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
               Extensions (MIME) Part One: Format of Internet Message
               Bodies", RFC 2045, November 1996.
  <!ENTITY ja.mime.fullname "多目的 Internet メイル拡張">
&ja.mime.fullname; (MIME)
   [RFC 2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
               Extensions (MIME) Part Two: Media Types", RFC 2046,
               November 1996.
   [RFC 2047]  Moore, K., "MIME (Multipurpose Internet Mail Extensions)
               Part Three: Message Header Extensions for Non-ASCII
               Text", RFC 2047, November 1996.
   [RFC 2048]  Freed, N., Klensin, J. and J. Postel, "Multipurpose
               Internet Mail Extensions (MIME) Part Four: Registration
               Procedures", RFC 2048, November 1996.
   [RFC 2049]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
               Extensions (MIME) Part Five: Conformance Criteria and
               Examples", RFC 2049, November 1996.
   [RFC 2119]  Bradner, S., "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119, March 1997.
RFC 中で要求水準を示すのに使うキーワード
   [RFC 2234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
               Specifications: ABNF", RFC 2234, November 1997.
   [RFC 2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
               Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
               Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
   [RFC 2822]  Resnick, P., "Internet Message Format", RFC 2822, April

Appendix A: Changes from RFC 1766

   The definition of the language tags has been split, and is now RFC
   3066.  The differences parameter to multipart/alternative is no
   longer part of this standard, because no implementations of the
   function were ever found.  Consult RFC 1766 if you need the
言語&ja.lang.tag;の定義は分離して、 RFC 3066 となりました。
multipart/alternative の differences (差異) パラメータは、この機能の実装が無かったので、この規格の部分では失くしました。もし情報が必要であれば、
RFC 1766 を御覧下さい。

The ABNF for content-language has been updated to use the RFC 2234 ABNF. content-language の ABNF を RFC 2234 ABNF に更新しました。

Author's Address

   Harald Tveit Alvestrand
   Cisco Systems
   Weidemanns vei 27
   7043 Trondheim
   EMail: Harald@Alvestrand.no
   Phone: +47 73 50 33 52

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