Internet Draft Marc Blanchet <draft-blanchet-preflang-00.txt> Viagenie inc. Expires in six months February 1998 Preferred Language Tag Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months. Internet-Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet-Drafts as reference material or to cite them other than as a "working draft" or "work in progress". To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). 1. Abstract This memo defines a new tag which will help users and servers to determine the best language in their communications. For example, error messages coming from SMTP servers or HTTP servers can use this tag to send those error messages in the preferred language for the user. 2. Introduction Messages sent by servers or applications to users are often in the english language because the server or the application have no prior knowledge of the preferred language of the end user. Sometimes, servers or applications send messages in the proper language of the user but they were preconfigured with a priori knowledge of the end user. In the context of internationalization of the Internet and in the context of internationalization of the protocols as discussed in [RFC-2277], it is much useful to know a priori which language a user wants to interact with. Since many protocols do not necessarily interact with the user by some negociation, like two SMTP servers relaying a email message, there is a need to give a list of preferred languages in order inside the tag, so that if, for example, a user is requesting french, swedish and then english as preferred languages, the server who don't have french error messages, will send the message in swedish or in english. 2.1. Other tags HTTP [RFC-2068] defines the tag Accept-Language, which defines not only a preferred language tag, but also a language quality factor assigned to it. Current work on LDAP[ldapextlang] defines an attribute type. 2.2. Requirements notation This document occasionally uses terms that appear in capital letters. When the terms "MUST", "SHOULD", "MUST NOT", "SHOULD NOT", and "MAY" appear capitalized, they are being used to indicate particular requirements of this specification. A discussion of the meanings of these terms appears in [RFC- 2119]. 3. Preferred Language Tag Language tag mechanism has been described in RFC-1766. This memo defines a new tag: Prefer-Language to specify the list of preferred languages that the user (or to be more general, the issuer of this tag which can be a process, server, ...) wants to receive when communicating with other parties. The values and the syntax associated with this new tag are those defined in RFC-1766. The language strings are separated by commas. The order of preference is from left to right, the first in the left position being the most preferred one. For example, this tag will specify that a user prefer french, if not possible deutsh, if not possible english: Prefer-Language: fr, de, en 4. Processing the tag This tag is optional. A server or a client MAY ignore it. But all proxies or forwarders MUST forward it. 5. Default language This memo defines no implicit default language. Default language is discussed in [RFC-2277]. 6. Placement of the tag This new tag will be normally placed in the headers of the protocols that use them. This memo do not attend to list protocols and specify where to place them. It is envisionned that software developers will put a config option, so the user can fill his requirements and the client software will send those tags in all communications. 7. ABNF The ABNF for this new tag is: preferred-language := "Prefer-Language" "=" language (separator language ) separator := "," language := <registered language tag [RFC-1766]> 8. Security Considerations The knowledge of a user's preferred language can help an attacker to impersonate the user by giving the receipient more confidence on the sender of the message. The applications that will process this tag should take care of restricting the values read in the tag to the syntax, so that if an attacker insert shell scripts or escapes in the values of these tags, they will not be interpreted by the application. 9. Acknowledgments Many thanks for the very constructive comments of: Harald T. Alverstrand, Martin J. Duerst, John Myers, Francois Yergeau 10. References [ldapextlang] Whal, M. and Howes, T., "Use of Language Codes in LDAP", work in progress (draft-ietf-ldapext-lang-00.txt), January 1998. [RFC-1766] Alvestrand, H., "Tags for the Identification of Languages", RFC 1766, March, 1995. [RFC-2045] Freed, N. and Borenstein, N., "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, Innosoft, First Virtual Holdings, December 1996. [RFC-2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC-2130] Weider, C., Preston, C., Simonsen, K., Alvestrand, H., Atkinson, R., Crispin, M., Svanberg, P., "Report from the IAB Character Set Workshop", RFC 2130, April 1997. [RFC-2277] Alvestrand, H., "IETF Policy on Character Sets and Languages" RFC 2277, January 1998. 11. Author Address Marc Blanchet Viagenie Inc. 3107 des hotels Ste-Foy, Quebec, G1W 4W5 Canada tel: +1 418 656-9254 fax: +1 418 656-0183 email: Marc.Blanchet@viagenie.qc.ca Prefer-Language: fr, en 12. Full Copyright Statement Copyright (C) The Internet Society (1998). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. ----------------------------------------------------------- Marc Blanchet | Marc.Blanchet@viagenie.qc.ca Viagenie inc. | http://www.viagenie.qc.ca 3107 des hotels | tel.: 418-656-9254 Ste-Foy, Quebec | fax.: 418-656-0183 Canada, G1W 4W5 | radio: VA2-JAZ ------------------------------------------------------------ pgp: 57 86 A6 83 D3 A8 58 32 F7 0A BB BD 5F B2 4B A7 ------------------------------------------------------------ Auteur du livre TCP/IP Simplifié, Editions Logiques, 1997 ------------------------------------------------------------