Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
draft-ietf-httpbis-p4-conditional-25

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26

HTTPbis Working Group                                   R. Fielding, Ed.
Internet-Draft                                                     Adobe
Obsoletes: 2616 (if approved)                            J. Reschke, Ed.
Intended status: Standards Track                              greenbytes
Expires: May 21, 2014                                  November 17, 2013

      Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
                  draft-ietf-httpbis-p4-conditional-25

Abstract

   The Hypertext Transfer Protocol (HTTP) is an application-level
   protocol for distributed, collaborative, hypertext information
   systems.  This document defines HTTP/1.1 conditional requests,
   including metadata header fields for indicating state changes,
   request header fields for making preconditions on such state, and
   rules for constructing the responses to a conditional request when
   one or more preconditions evaluate to false.

Editorial Note (To be removed by RFC Editor)

   Discussion of this draft takes place on the HTTPBIS working group
   mailing list (ietf-http-wg@w3.org), which is archived at
   <http://lists.w3.org/Archives/Public/ietf-http-wg/>.

   The current issues list is at
   <http://tools.ietf.org/wg/httpbis/trac/report/3> and related
   documents (including fancy diffs) can be found at
   <http://tools.ietf.org/wg/httpbis/>.

   The changes in this draft are summarized in Appendix D.1.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

Fielding & Reschke        Expires May 21, 2014                  [Page 1]
Internet-Draft        HTTP/1.1 Conditional Requests        November 2013

   This Internet-Draft will expire on May 21, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Fielding & Reschke        Expires May 21, 2014                  [Page 2]
Internet-Draft        HTTP/1.1 Conditional Requests        November 2013

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Conformance and Error Handling . . . . . . . . . . . . . .  4
     1.2.  Syntax Notation  . . . . . . . . . . . . . . . . . . . . .  4
   2.  Validators . . . . . . . . . . . . . . . . . . . . . . . . . .  5
     2.1.  Weak versus Strong . . . . . . . . . . . . . . . . . . . .  5
     2.2.  Last-Modified  . . . . . . . . . . . . . . . . . . . . . .  7
       2.2.1.  Generation . . . . . . . . . . . . . . . . . . . . . .  7
       2.2.2.  Comparison . . . . . . . . . . . . . . . . . . . . . .  8
     2.3.  ETag . . . . . . . . . . . . . . . . . . . . . . . . . . .  9
       2.3.1.  Generation . . . . . . . . . . . . . . . . . . . . . .  9
       2.3.2.  Comparison . . . . . . . . . . . . . . . . . . . . . . 10
       2.3.3.  Example: Entity-tags Varying on Content-Negotiated
               Resources  . . . . . . . . . . . . . . . . . . . . . . 11
     2.4.  When to Use Entity-tags and Last-Modified Dates  . . . . . 12