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Hypertext Transfer Protocol (HTTP/1.1): Caching
draft-ietf-httpbis-p6-cache-26

Document type: Active Internet-Draft (httpbis WG)
Document stream: IETF
Last updated: 2014-02-18 (latest revision 2014-02-06)
Intended RFC status: Proposed Standard
Other versions: plain text, xml, pdf, html

IETF State: Submitted to IESG for Publication Sep 2013
Consensus: Yes
Document shepherd: Mark Baker
Shepherd Write-Up: Last changed 2013-10-21

IESG State: RFC Ed Queue
IANA Action State: RFC-Ed-Ack
RFC Editor State: RFC-EDITOR
Responsible AD: Barry Leiba
Send notices to: httpbis-chairs@tools.ietf.org, draft-ietf-httpbis-p6-cache@tools.ietf.org

HTTPbis Working Group                                   R. Fielding, Ed.
Internet-Draft                                                     Adobe
Obsoletes: 2616 (if approved)                         M. Nottingham, Ed.
Intended status: Standards Track                                  Akamai
Expires: August 10, 2014                                 J. Reschke, Ed.
                                                              greenbytes
                                                        February 6, 2014

            Hypertext Transfer Protocol (HTTP/1.1): Caching
                     draft-ietf-httpbis-p6-cache-26

Abstract

   The Hypertext Transfer Protocol (HTTP) is a stateless application-
   level protocol for distributed, collaborative, hypertext information
   systems.  This document defines HTTP caches and the associated header
   fields that control cache behavior or indicate cacheable response
   messages.

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.2.

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, et al.         Expires August 10, 2014                [Page 1]
Internet-Draft              HTTP/1.1 Caching               February 2014

   This Internet-Draft will expire on August 10, 2014.

Copyright Notice

   Copyright (c) 2014 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
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   include Simplified BSD License text as described in Section 4.e of
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   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.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Conformance and Error Handling . . . . . . . . . . . . . .  4
     1.2.  Syntax Notation  . . . . . . . . . . . . . . . . . . . . .  4
       1.2.1.  Delta Seconds  . . . . . . . . . . . . . . . . . . . .  5
   2.  Overview of Cache Operation  . . . . . . . . . . . . . . . . .  5
   3.  Storing Responses in Caches  . . . . . . . . . . . . . . . . .  6
     3.1.  Storing Incomplete Responses . . . . . . . . . . . . . . .  7
     3.2.  Storing Responses to Authenticated Requests  . . . . . . .  7
     3.3.  Combining Partial Content  . . . . . . . . . . . . . . . .  8
   4.  Constructing Responses from Caches . . . . . . . . . . . . . .  8
     4.1.  Calculating Secondary Keys with Vary . . . . . . . . . . .  9
     4.2.  Freshness  . . . . . . . . . . . . . . . . . . . . . . . . 10
       4.2.1.  Calculating Freshness Lifetime . . . . . . . . . . . . 12
       4.2.2.  Calculating Heuristic Freshness  . . . . . . . . . . . 12
       4.2.3.  Calculating Age  . . . . . . . . . . . . . . . . . . . 13
       4.2.4.  Serving Stale Responses  . . . . . . . . . . . . . . . 15

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