Prefer Header for HTTP
draft-snell-http-prefer-13
The information below is for an old version of the document |
Document |
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Active Internet-Draft (individual in app area)
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Author |
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James Snell
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Last updated |
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2012-08-20
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Stream |
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IETF
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Intended RFC status |
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Proposed Standard
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Formats |
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pdf
htmlized (tools)
htmlized
bibtex
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Reviews |
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WG state
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(None)
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Document shepherd |
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None
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IESG |
IESG state |
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I-D Exists (IESG: Dead)
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Consensus Boilerplate |
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Unknown
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Telechat date |
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Responsible AD |
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Barry Leiba
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IESG note |
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Mark Nottingham is the document shepherd.
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Send notices to |
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jasnell@gmail.com, mnot@mnot.net, draft-snell-http-prefer@tools.ietf.org
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Network Working Group J. Snell
Internet-Draft August 21, 2012
Intended status: Standards Track
Expires: February 22, 2013
Prefer Header for HTTP
draft-snell-http-prefer-13
Abstract
This specification defines an HTTP header field that can be used by a
client to request that certain behaviors be implemented by a server
while processing a request.
Status of this Memo
This Internet-Draft is submitted to IETF 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."
This Internet-Draft will expire on February 22, 2013.
Copyright Notice
Copyright (c) 2012 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.
Snell Expires February 22, 2013 [Page 1]
Internet-Draft HTTP Prefer August 2012
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 3
2. The Prefer Request Header Field . . . . . . . . . . . . . . . 3
2.1. Content Negotiation and Cache Considerations . . . . . . . 5
2.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. The "return-asynch" Preference . . . . . . . . . . . . . . . . 5
4. The "return-representation" Preference . . . . . . . . . . . . 6
5. The "return-minimal" Preference . . . . . . . . . . . . . . . 7
6. The "wait" Preference . . . . . . . . . . . . . . . . . . . . 8
7. The "strict" and "lenient" Processing Preferences . . . . . . 9
8. Registered Preferences . . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
9.1. The Registry of Preferences . . . . . . . . . . . . . . . 11
9.1.1. Initial Registry Contents . . . . . . . . . . . . . . 12
10. Security Considerations . . . . . . . . . . . . . . . . . . . 12
11. Normative References . . . . . . . . . . . . . . . . . . . . . 13
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14
Snell Expires February 22, 2013 [Page 2]
Internet-Draft HTTP Prefer August 2012
1. Introduction
This specification defines a new HTTP request header field that can
be used by clients to request optional behaviors be applied by a
server during the processing the request.
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in [RFC2119].
1.1. Syntax Notation
This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234] and includes, by reference, the "word", "OWS",
"BWS" rules and the #rule extension as defined within Sections 1.2
and 3.2.4 of [I-D.ietf-httpbis-p1-messaging].
2. The Prefer Request Header Field
The Prefer request-header field is used to indicate that particular
server behaviors are preferred by the client, but not required for
successful completion of the request. Prefer is similar in nature to
the Expect header field defined by Section 9.3 of
[I-D.ietf-httpbis-p2-semantics] with the exception that servers are
allowed to ignore stated preferences.
Prefer = "Prefer" ":" 1#preference
preference = token [ BWS "=" BWS word ]
*( OWS ";" [ OWS parameter ] )
parameter = token [ BWS "=" BWS word ]
This header field is defined with an extensible syntax to allow for
future values included in the Registry of Preferences (Section 9.1).
A server that does not recognize or is unable to comply with
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