Network Working Group                                      S. Harhalakis
Internet-Draft                                       TEI of Thessaloniki
Intended status: Standards Track                             Jun 8, 2007
Expires: Dec 08, 2007

                      Timezone Information in HTTP
                    draft-sharhalakis-httptz-01.txt

Status of this Memo

   Distribution of this memo is unlimited.

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   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
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on December 8, 2007.

   Discussion about this document takes place in http-wg mailing list
   (ietf-http-wg@w3.org).

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This document defines a HTTP header for clients to provide timezone
   information to web servers.  An ABNF description of the corresponding
   header is provided.

1.  Introduction



Harhalakis         Expires Dec 08, 2007                 FORMFEED[Page 1]


Internet Draft     Timezone in HTTP   Jun 08, 2007


1.1.  Purpose

   Many web based applications could benefit from knowing the timezone
   of their visiting clients.  Most of the dynamic content provider
   applications depend on user accounts to display time and date in the
   client's native timezone.  Even this is not always enough since
   people may travel across timezone boundaries and they currently need
   to update their web accounts to reflect their actual timezone
   information.

   This document addresses this need by describing a header to be used
   by HTTP [RFC2616] so that interested clients may  provide their
   current timezone information to web servers and thus to web based
   applications.

1.2.  Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.

   An implementation is not compliant if it fails to satisfy one or more
   of the MUST or REQUIRED level requirements.  An implementation that
   satisfies all the MUST or REQUIRED level and all the SHOULD level
   requirements is said to be "unconditionally compliant"; one that
   satisfies all the MUST level requirements but not all the SHOULD
   level requirements is said to be "conditionally compliant".

1.3.  Terminology

   This document uses the following terms:

   HTTP client
      Every client of the HTTP protocol.  Commonly referred to as a web
      browser.

   timezone
      A timezone string as described in [POSIXTZ].

   HTTP header
      A HTTP header as described in [RFC2616].

   The HTTP header specification of this document is presented in the
   augmented Backus-Naur Form that is described in [RFC2616].

2.  Definition

2.1.  Client support



Harhalakis         Expires Dec 08, 2007                 FORMFEED[Page 2]


Internet Draft     Timezone in HTTP   Jun 08, 2007


   HTTP clients MAY provide local timezone information to visiting web
   sites.  This information is send using the client-timezone HTTP
   header:

      client-timezone = "Timezone" ":" timezone

   Where 'timezone' is in the format specified in [POSIXTZ].

2.2.  Server support

   Compliant servers MAY validate the format of the provided
   information.  Timezone strings that are not in a valid format MAY not
   be accepted.  Validity checking MUST NOT be performed on the content
   of the timezone string by servers.  Only the format of the string may
   be checked.  This way outdated servers will not filter out proper
   information.

2.3.  Proxy considerations

   HTTP proxy servers MUST NOT alter this information.

3.  Security Considerations

3.1.  Client Side

   Timezone information may consist personal information regarding the
   location of a person.  HTTP clients MUST NOT provide this information
   without letting the user prevent it.  Clients must either ask users
   or provide an option for enabling/disabling this feature.  The later
   is RECOMMENDED.

3.2.  Server Side

   Web based applications MUST treat this information as user input that
   can be either valid or invalid.

4.  IANA Considerations

   This specification requires registration of a Message Header Field
   for HTTP [RFC3864].

   Header field: Timezone
   Applicable protocol: http
   Status: experimental
   Author/change controller:
       IETF  (iesg@ietf.org)
       Internet Engineering Task Force
   Specification document(s):



Harhalakis         Expires Dec 08, 2007                 FORMFEED[Page 3]


Internet Draft     Timezone in HTTP   Jun 08, 2007


      [ this document ]

5.  Acknowledgements

   It should be mentioned that the timezone information in HTTP was also
   proposed by David Robinson in an email at HTTP Working Group back in
   1995 but the replies he got were negative.  It was believed that
   timezone information should be handled by CGI scripts and not by the
   Hypertext Transfer Protocol.  The discussion can be found at http-wg
   mailing list archives:
   http://www.hpl.hp.com/personal/ange/archives/archives-95/http-wg-
   archive/0521.html.

   This document was properly formed thanks to the remarks of Julian
   Reschke.

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2616]  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.

   [RFC3864]  Klyne, G., Nottingham, M., and J. Mogul, "Registration
              Procedures for Message Header Fields", BCP 90, RFC 3864,
              September 2004.

   [POSIXTZ]  "Standard for Information Technology - Portable Operating
              System Interface (POSIX) - Base Definitions", IEEE Std
              1003.1-2004, December 2004.

6.2.  Informative References

   [2223BIS]  Reynolds, J. and R. Braden, "Instructions to Request for
              Comments (RFC) Authors", draft-rfc-editor-
              rfc2223bis-08.txt, August 2004.

   [RFC4234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 4234, October 2005.

Author's Address

   Stefanos Harhalakis
   Technological Educational Institute of Thessaloniki



Harhalakis         Expires Dec 08, 2007                 FORMFEED[Page 4]


Internet Draft     Timezone in HTTP   Jun 08, 2007


   Department of Information Technology
   Thessaloniki, Greece

   EMail: v13@it.teithe.gr, v13@priest.com















































Harhalakis         Expires Dec 08, 2007                 FORMFEED[Page 5]


Internet Draft     Timezone in HTTP   Jun 08, 2007


Full Copyright Statement

   Copyright (C) The IETF Trust (2007)

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST,
   AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.

Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org.











Harhalakis         Expires Dec 08, 2007                 FORMFEED[Page 6]