Network Working Group S. Harhalakis Internet-Draft TEI of Thessaloniki Intended status: Standards Track Jun 5, 2007 Updates: RFC2616 (if approved) Expires: Dec 05, 2007 Timezone Information in HTTP draft-sharhalakis-httptz-00.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 November 8, 2007. 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 1.1. Purpose Harhalakis Expires Dec 05, 2007 FORMFEED[Page 1] Internet Draft Timezone in HTTP Jun 05, 2007 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 [RFC2119] 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 some terms to identify the roles of the participants: 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 An HTTP header as described in [RFC2119]. 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 05, 2007 FORMFEED[Page 2] Internet Draft Timezone in HTTP Jun 05, 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. Acknowledgment 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. 5. References 5.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Harhalakis Expires Dec 05, 2007 FORMFEED[Page 3] Internet Draft Timezone in HTTP Jun 05, 2007 [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. [POSIXTZ] "Standard for Information Technology - Portable Operating System Interface (POSIX) - Base Definitions", IEEE Std 1003.1-2004, December 2004. 5.2. 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 Department of Information Technology Thessaloniki, Greece EMail: v13@it.teithe.gr, v13@priest.com Harhalakis Expires Dec 05, 2007 FORMFEED[Page 4] Internet Draft Timezone in HTTP Jun 05, 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. 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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 05, 2007 FORMFEED[Page 5]