INTERNET-DRAFT M. Yevstifeyev
Intended Status: Experimental January 8, 2011
Expires: July 12, 2011
HTTP 'Headers-Not-Recognized' Header Field
<draft-yevstifeyev-http-headers-not-recognized-11>
Abstract
This document defines mechanism which allows HTTP hosts to notify
another hosts about not supported header fields - 'Headers-Not-
Recognized' HTTP header field.
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), 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
Copyright and License Notice
Copyright (c) 2011 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
Yevstifeyev Expires July 12, 2011 [Page 1]
INTERNET DRAFT Headers-Not-Recognized for HTTP January 8, 2011
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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2.1. Conformance Criteria . . . . . . . . . . . . . . . . . 3
1.2.2. Syntax Notation . . . . . . . . . . . . . . . . . . . 3
1.2.3. Terminology . . . . . . . . . . . . . . . . . . . . . 3
2. Technical Overview . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Model of Work . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
5. Normative References . . . . . . . . . . . . . . . . . . . . . . 5
Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Yevstifeyev Expires July 12, 2011 [Page 2]
INTERNET DRAFT Headers-Not-Recognized for HTTP January 8, 2011
1. Introduction
1.1. Motivation
HTTP is one of the most widely-used protocols in the Internet. One
of the things which made it so popular is extensibility. One can
easily add any header field to the HTTP message. However, all hosts
are not able to support all the header fields. Generally, if a it
host does not support the header field, it is simply ignored. The
another side of exchange is not notified about not processed header
fields.
This document proposes mechanism which allows HTTP hosts to notify
another hosts about not recognized header fields.
The proposal is to send an HTTP message with definite header field to
the host if one or more header fields of its message are not
supported. This document defines 'Headers-Not-Recognized' HTTP header
field to be used in such occasion.
1.2. Conventions
1.2.1. Conformance Criteria
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 [RFC2119].
1.2.2. Syntax Notation
This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234].
The construction <n>#<m>element is used as defined in RFC 2616
[RFC2616], Section 2.1.
1.2.3. Terminology
HTTP refers to protocol, defined in RFC 2616 [RFC2616]
The terms client, server, proxy, gateway and tunnel have the same
meaning as in the HTTP/1.1 specification ([RFC2616], Section 1.3).
The term host means client or server.
Yevstifeyev Expires July 12, 2011 [Page 3]
INTERNET DRAFT Headers-Not-Recognized for HTTP January 8, 2011
2. Technical Overview
2.1 Model of Work
If the HTTP host receives HTTP message which contains some header
fields which are not supported by it, it is RECOMMENDED for it to
include the Headers-Not-Recognized header field in the response to
the host that sent message with not supported header fields.
Information about not supported header fields is to be put in the
'Headers-Not-Recognized' header field following the rules of Section
2.2 of this document. The 'Headers-Not-Recognized' header field MUST
contain information only about not supported header fields - i.e.
header fields which are not able to be processed anyway. It MUST NOT
contain information about header fields, which are partly supported,
whose entity cannot be processed while the header field is supported
at all, etc.
When HTTP host receives HTTP message with Headers-Not-Recognized
header field, it is RECOMMENDED that it avoids sending messages with
header fields with mentioned in it names to source (for such message)
host.
Intermediate systems (also called middle-boxes), such as proxies,
tunnels, gateways, etc. SHALL transfer the messages with 'Headers-
Not-Recognized' header field to the destination host without changing
the entity of this header field if the not supported header field was
present in the initial HTTP message (i. e. message which intermediate
system received before transferring it to destination host), but
SHALL omit it if Headers-Not-Recognized header field's entity
concerns only to header fields added to initial message by middle-
box. If the aforementioned header field concerns added header fields
partly, middle-box SHALL change the entity so that it concerns only
initial message header field.
2.2 Syntax
'Headers-Not-Recognized' header field has the following format:
headers_not_recognized = 1#header_name
header_name = 1*VCHAR
Yevstifeyev Expires July 12, 2011 [Page 4]
INTERNET DRAFT Headers-Not-Recognized for HTTP January 8, 2011
3. IANA Considerations
The permanent message header field registry should be updated with
the following registration (see [RFC3864]):
Header field name
Headers-Not-Recognized
Applicable protocol
http
Status
experimental
Specification document
RFC xxxx
[RFC Editor: replace xxxx with assigned RFC number]
[Note: This registration should take place at
http://www.iana.org/assignments/message-headers/perm-headers.html
This note is to be deleted upon publication.]
4. Security Considerations
This extension to HTTP is not believed to add any additional security
concerns not already present in RFC 2616 [RFC2616].
5. Normative References
[RFC2119] S. Bradner, "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.
[RFC5234] Crocker, D., Ed., and P. Overell, "Augmented BNF for
Syntax Specifications: ABNF", STD 68, RFC 5234, January
2008.
Yevstifeyev Expires July 12, 2011 [Page 5]
INTERNET DRAFT Headers-Not-Recognized for HTTP January 8, 2011
Author's Addresses
Mykyta Yevstifeyev
Kotovsk, Ukraine
EMail: evnikita2@gmail.com
Yevstifeyev Expires July 12, 2011 [Page 6]
