draft-ietf-httpbis-p3-payload-18.txt   draft-ietf-httpbis-p3-payload-19.txt 
HTTPbis Working Group R. Fielding, Ed. HTTPbis Working Group R. Fielding, Ed.
Internet-Draft Adobe Internet-Draft Adobe
Obsoletes: 2616 (if approved) J. Gettys Obsoletes: 2616 (if approved) Y. Lafon, Ed.
Intended status: Standards Track Alcatel-Lucent Intended status: Standards Track W3C
Expires: July 7, 2012 J. Mogul Expires: September 13, 2012 J. Reschke, Ed.
HP
H. Frystyk
Microsoft
L. Masinter
Adobe
P. Leach
Microsoft
T. Berners-Lee
W3C/MIT
Y. Lafon, Ed.
W3C
J. Reschke, Ed.
greenbytes greenbytes
January 4, 2012 March 12, 2012
HTTP/1.1, part 3: Message Payload and Content Negotiation HTTP/1.1, part 3: Message Payload and Content Negotiation
draft-ietf-httpbis-p3-payload-18 draft-ietf-httpbis-p3-payload-19
Abstract Abstract
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is an application-level
protocol for distributed, collaborative, hypertext information protocol for distributed, collaborative, hypertext information
systems. HTTP has been in use by the World Wide Web global systems. HTTP has been in use by the World Wide Web global
information initiative since 1990. This document is Part 3 of the information initiative since 1990. This document is Part 3 of the
seven-part specification that defines the protocol referred to as seven-part specification that defines the protocol referred to as
"HTTP/1.1" and, taken together, obsoletes RFC 2616. "HTTP/1.1" and, taken together, obsoletes RFC 2616.
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Discussion of this draft should take place on the HTTPBIS working Discussion of this draft should take place on the HTTPBIS working
group mailing list (ietf-http-wg@w3.org), which is archived at group mailing list (ietf-http-wg@w3.org), which is archived at
<http://lists.w3.org/Archives/Public/ietf-http-wg/>. <http://lists.w3.org/Archives/Public/ietf-http-wg/>.
The current issues list is at The current issues list is at
<http://tools.ietf.org/wg/httpbis/trac/report/3> and related <http://tools.ietf.org/wg/httpbis/trac/report/3> and related
documents (including fancy diffs) can be found at documents (including fancy diffs) can be found at
<http://tools.ietf.org/wg/httpbis/>. <http://tools.ietf.org/wg/httpbis/>.
The changes in this draft are summarized in Appendix E.19. The changes in this draft are summarized in Appendix E.20.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 7, 2012. This Internet-Draft will expire on September 13, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.2. Conformance and Error Handling . . . . . . . . . . . . . . 5 1.2. Conformance and Error Handling . . . . . . . . . . . . . . 5
1.3. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 6 1.3. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 6
1.3.1. Core Rules . . . . . . . . . . . . . . . . . . . . . . 6 1.3.1. Core Rules . . . . . . . . . . . . . . . . . . . . . . 6
1.3.2. ABNF Rules defined in other Parts of the 1.3.2. ABNF Rules defined in other Parts of the
Specification . . . . . . . . . . . . . . . . . . . . 6 Specification . . . . . . . . . . . . . . . . . . . . 6
2. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 6 2. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 7
2.1. Character Encodings (charset) . . . . . . . . . . . . . . 6 2.1. Character Encodings (charset) . . . . . . . . . . . . . . 7
2.2. Content Codings . . . . . . . . . . . . . . . . . . . . . 7 2.2. Content Codings . . . . . . . . . . . . . . . . . . . . . 7
2.2.1. Content Coding Registry . . . . . . . . . . . . . . . 8 2.2.1. Content Coding Registry . . . . . . . . . . . . . . . 8
2.3. Media Types . . . . . . . . . . . . . . . . . . . . . . . 8 2.3. Media Types . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.1. Canonicalization and Text Defaults . . . . . . . . . . 9 2.3.1. Canonicalization and Text Defaults . . . . . . . . . . 9
2.3.2. Multipart Types . . . . . . . . . . . . . . . . . . . 9 2.3.2. Multipart Types . . . . . . . . . . . . . . . . . . . 10
2.4. Language Tags . . . . . . . . . . . . . . . . . . . . . . 10 2.4. Language Tags . . . . . . . . . . . . . . . . . . . . . . 10
3. Payload . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3. Payload . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1. Payload Header Fields . . . . . . . . . . . . . . . . . . 11 3.1. Payload Header Fields . . . . . . . . . . . . . . . . . . 11
3.2. Payload Body . . . . . . . . . . . . . . . . . . . . . . . 11 3.2. Payload Body . . . . . . . . . . . . . . . . . . . . . . . 11
4. Representation . . . . . . . . . . . . . . . . . . . . . . . . 11 4. Representation . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Representation Header Fields . . . . . . . . . . . . . . . 12 4.1. Representation Header Fields . . . . . . . . . . . . . . . 12
4.2. Representation Data . . . . . . . . . . . . . . . . . . . 12 4.2. Representation Data . . . . . . . . . . . . . . . . . . . 13
5. Content Negotiation . . . . . . . . . . . . . . . . . . . . . 13 5. Content Negotiation . . . . . . . . . . . . . . . . . . . . . 13
5.1. Server-driven Negotiation . . . . . . . . . . . . . . . . 14 5.1. Server-driven Negotiation . . . . . . . . . . . . . . . . 14
5.2. Agent-driven Negotiation . . . . . . . . . . . . . . . . . 15 5.2. Agent-driven Negotiation . . . . . . . . . . . . . . . . . 16
6. Header Field Definitions . . . . . . . . . . . . . . . . . . . 16 6. Header Field Definitions . . . . . . . . . . . . . . . . . . . 16
6.1. Accept . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6.1. Accept . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.2. Accept-Charset . . . . . . . . . . . . . . . . . . . . . . 18 6.2. Accept-Charset . . . . . . . . . . . . . . . . . . . . . . 19
6.3. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 19 6.3. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 19
6.4. Accept-Language . . . . . . . . . . . . . . . . . . . . . 20 6.4. Accept-Language . . . . . . . . . . . . . . . . . . . . . 21
6.5. Content-Encoding . . . . . . . . . . . . . . . . . . . . . 21 6.5. Content-Encoding . . . . . . . . . . . . . . . . . . . . . 22
6.6. Content-Language . . . . . . . . . . . . . . . . . . . . . 22 6.6. Content-Language . . . . . . . . . . . . . . . . . . . . . 23
6.7. Content-Location . . . . . . . . . . . . . . . . . . . . . 23 6.7. Content-Location . . . . . . . . . . . . . . . . . . . . . 23
6.8. Content-Type . . . . . . . . . . . . . . . . . . . . . . . 25 6.8. Content-Type . . . . . . . . . . . . . . . . . . . . . . . 25
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
7.1. Header Field Registration . . . . . . . . . . . . . . . . 25 7.1. Header Field Registration . . . . . . . . . . . . . . . . 25
7.2. Content Coding Registry . . . . . . . . . . . . . . . . . 25 7.2. Content Coding Registry . . . . . . . . . . . . . . . . . 26
8. Security Considerations . . . . . . . . . . . . . . . . . . . 26 8. Security Considerations . . . . . . . . . . . . . . . . . . . 26
8.1. Privacy Issues Connected to Accept Header Fields . . . . . 26 8.1. Privacy Issues Connected to Accept Header Fields . . . . . 27
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10.1. Normative References . . . . . . . . . . . . . . . . . . . 27 10.1. Normative References . . . . . . . . . . . . . . . . . . . 27
10.2. Informative References . . . . . . . . . . . . . . . . . . 28 10.2. Informative References . . . . . . . . . . . . . . . . . . 29
Appendix A. Differences between HTTP and MIME . . . . . . . . . . 29 Appendix A. Differences between HTTP and MIME . . . . . . . . . . 30
A.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . . 30 A.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . . 30
A.2. Conversion to Canonical Form . . . . . . . . . . . . . . . 30 A.2. Conversion to Canonical Form . . . . . . . . . . . . . . . 31
A.3. Conversion of Date Formats . . . . . . . . . . . . . . . . 31 A.3. Conversion of Date Formats . . . . . . . . . . . . . . . . 31
A.4. Introduction of Content-Encoding . . . . . . . . . . . . . 31 A.4. Introduction of Content-Encoding . . . . . . . . . . . . . 31
A.5. No Content-Transfer-Encoding . . . . . . . . . . . . . . . 31 A.5. No Content-Transfer-Encoding . . . . . . . . . . . . . . . 32
A.6. Introduction of Transfer-Encoding . . . . . . . . . . . . 32 A.6. Introduction of Transfer-Encoding . . . . . . . . . . . . 32
A.7. MHTML and Line Length Limitations . . . . . . . . . . . . 32 A.7. MHTML and Line Length Limitations . . . . . . . . . . . . 32
Appendix B. Additional Features . . . . . . . . . . . . . . . . . 32 Appendix B. Additional Features . . . . . . . . . . . . . . . . . 32
Appendix C. Changes from RFC 2616 . . . . . . . . . . . . . . . . 32 Appendix C. Changes from RFC 2616 . . . . . . . . . . . . . . . . 33
Appendix D. Collected ABNF . . . . . . . . . . . . . . . . . . . 33 Appendix D. Collected ABNF . . . . . . . . . . . . . . . . . . . 33
Appendix E. Change Log (to be removed by RFC Editor before Appendix E. Change Log (to be removed by RFC Editor before
publication) . . . . . . . . . . . . . . . . . . . . 34 publication) . . . . . . . . . . . . . . . . . . . . 35
E.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 34 E.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 35
E.2. Since draft-ietf-httpbis-p3-payload-00 . . . . . . . . . . 34 E.2. Since draft-ietf-httpbis-p3-payload-00 . . . . . . . . . . 35
E.3. Since draft-ietf-httpbis-p3-payload-01 . . . . . . . . . . 35 E.3. Since draft-ietf-httpbis-p3-payload-01 . . . . . . . . . . 36
E.4. Since draft-ietf-httpbis-p3-payload-02 . . . . . . . . . . 35 E.4. Since draft-ietf-httpbis-p3-payload-02 . . . . . . . . . . 36
E.5. Since draft-ietf-httpbis-p3-payload-03 . . . . . . . . . . 36 E.5. Since draft-ietf-httpbis-p3-payload-03 . . . . . . . . . . 36
E.6. Since draft-ietf-httpbis-p3-payload-04 . . . . . . . . . . 36 E.6. Since draft-ietf-httpbis-p3-payload-04 . . . . . . . . . . 37
E.7. Since draft-ietf-httpbis-p3-payload-05 . . . . . . . . . . 36 E.7. Since draft-ietf-httpbis-p3-payload-05 . . . . . . . . . . 37
E.8. Since draft-ietf-httpbis-p3-payload-06 . . . . . . . . . . 37 E.8. Since draft-ietf-httpbis-p3-payload-06 . . . . . . . . . . 37
E.9. Since draft-ietf-httpbis-p3-payload-07 . . . . . . . . . . 37 E.9. Since draft-ietf-httpbis-p3-payload-07 . . . . . . . . . . 38
E.10. Since draft-ietf-httpbis-p3-payload-08 . . . . . . . . . . 38 E.10. Since draft-ietf-httpbis-p3-payload-08 . . . . . . . . . . 38
E.11. Since draft-ietf-httpbis-p3-payload-09 . . . . . . . . . . 38 E.11. Since draft-ietf-httpbis-p3-payload-09 . . . . . . . . . . 39
E.12. Since draft-ietf-httpbis-p3-payload-10 . . . . . . . . . . 38 E.12. Since draft-ietf-httpbis-p3-payload-10 . . . . . . . . . . 39
E.13. Since draft-ietf-httpbis-p3-payload-11 . . . . . . . . . . 39 E.13. Since draft-ietf-httpbis-p3-payload-11 . . . . . . . . . . 40
E.14. Since draft-ietf-httpbis-p3-payload-12 . . . . . . . . . . 39 E.14. Since draft-ietf-httpbis-p3-payload-12 . . . . . . . . . . 40
E.15. Since draft-ietf-httpbis-p3-payload-13 . . . . . . . . . . 39 E.15. Since draft-ietf-httpbis-p3-payload-13 . . . . . . . . . . 40
E.16. Since draft-ietf-httpbis-p3-payload-14 . . . . . . . . . . 40 E.16. Since draft-ietf-httpbis-p3-payload-14 . . . . . . . . . . 40
E.17. Since draft-ietf-httpbis-p3-payload-15 . . . . . . . . . . 40 E.17. Since draft-ietf-httpbis-p3-payload-15 . . . . . . . . . . 41
E.18. Since draft-ietf-httpbis-p3-payload-16 . . . . . . . . . . 40 E.18. Since draft-ietf-httpbis-p3-payload-16 . . . . . . . . . . 41
E.19. Since draft-ietf-httpbis-p3-payload-17 . . . . . . . . . . 40 E.19. Since draft-ietf-httpbis-p3-payload-17 . . . . . . . . . . 41
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 E.20. Since draft-ietf-httpbis-p3-payload-18 . . . . . . . . . . 41
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction 1. Introduction
This document defines HTTP/1.1 message payloads (a.k.a., content), This document defines HTTP/1.1 message payloads (a.k.a., content),
the associated metadata header fields that define how the payload is the associated metadata header fields that define how the payload is
intended to be interpreted by a recipient, the request header fields intended to be interpreted by a recipient, the request header fields
that might influence content selection, and the various selection that might influence content selection, and the various selection
algorithms that are collectively referred to as HTTP content algorithms that are collectively referred to as HTTP content
negotiation. negotiation.
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This specification uses a number of terms to refer to the roles This specification uses a number of terms to refer to the roles
played by participants in, and objects of, the HTTP communication. played by participants in, and objects of, the HTTP communication.
content negotiation content negotiation
The mechanism for selecting the appropriate representation when The mechanism for selecting the appropriate representation when
servicing a request. The representation in any response can be servicing a request. The representation in any response can be
negotiated (including error responses). negotiated (including error responses).
selected representation
The current representation of the target resource that would have
been selected in a successful response if the same request had
used the method GET and excluded any conditional request header
fields.
1.2. Conformance and Error Handling 1.2. Conformance and Error Handling
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
This document defines conformance criteria for several roles in HTTP This document defines conformance criteria for several roles in HTTP
communication, including Senders, Recipients, Clients, Servers, User- communication, including Senders, Recipients, Clients, Servers, User-
Agents, Origin Servers, Intermediaries, Proxies and Gateways. See Agents, Origin Servers, Intermediaries, Proxies and Gateways. See
Section 2 of [Part1] for definitions of these terms. Section 2 of [Part1] for definitions of these terms.
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define specific error handling mechanisms, except in cases where it define specific error handling mechanisms, except in cases where it
has direct impact on security. This is because different uses of the has direct impact on security. This is because different uses of the
protocol require different error handling strategies; for example, a protocol require different error handling strategies; for example, a
Web browser may wish to transparently recover from a response where Web browser may wish to transparently recover from a response where
the Location header field doesn't parse according to the ABNF, the Location header field doesn't parse according to the ABNF,
whereby in a systems control protocol using HTTP, this type of error whereby in a systems control protocol using HTTP, this type of error
recovery could lead to dangerous consequences. recovery could lead to dangerous consequences.
1.3. Syntax Notation 1.3. Syntax Notation
This specification uses the ABNF syntax defined in Section 1.2 of This specification uses the Augmented Backus-Naur Form (ABNF)
[Part1] (which extends the syntax defined in [RFC5234] with a list notation of [RFC5234] with the list rule extension defined in Section
rule). Appendix D shows the collected ABNF, with the list rule 1.2 of [Part1]. Appendix D shows the collected ABNF with the list
expanded. rule expanded.
The following core rules are included by reference, as defined in The following core rules are included by reference, as defined in
[RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF [RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF
(CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit
sequence of data), SP (space), and VCHAR (any visible US-ASCII sequence of data), SP (space), and VCHAR (any visible US-ASCII
character). character).
1.3.1. Core Rules 1.3.1. Core Rules
The core rules below are defined in [Part1]: The core rules below are defined in [Part1]:
OWS = <OWS, defined in [Part1], Section 1.2.2> OWS = <OWS, defined in [Part1], Section 3.2.1>
token = <token, defined in [Part1], Section 3.2.3> token = <token, defined in [Part1], Section 3.2.4>
word = <word, defined in [Part1], Section 3.2.3> word = <word, defined in [Part1], Section 3.2.4>
1.3.2. ABNF Rules defined in other Parts of the Specification 1.3.2. ABNF Rules defined in other Parts of the Specification
The ABNF rules below are defined in other parts: The ABNF rules below are defined in other parts:
absolute-URI = <absolute-URI, defined in [Part1], Section 2.7> absolute-URI = <absolute-URI, defined in [Part1], Section 2.7>
partial-URI = <partial-URI, defined in [Part1], Section 2.7> partial-URI = <partial-URI, defined in [Part1], Section 2.7>
qvalue = <qvalue, defined in [Part1], Section 5.3> qvalue = <qvalue, defined in [Part1], Section 4.3.1>
2. Protocol Parameters 2. Protocol Parameters
2.1. Character Encodings (charset) 2.1. Character Encodings (charset)
HTTP uses charset names to indicate the character encoding of a HTTP uses charset names to indicate the character encoding of a
textual representation. textual representation.
A character encoding is identified by a case-insensitive token. The A character encoding is identified by a case-insensitive token. The
complete set of tokens is defined by the IANA Character Set registry complete set of tokens is defined by the IANA Character Set registry
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content-coding = token content-coding = token
All content-coding values are case-insensitive. HTTP/1.1 uses All content-coding values are case-insensitive. HTTP/1.1 uses
content-coding values in the Accept-Encoding (Section 6.3) and content-coding values in the Accept-Encoding (Section 6.3) and
Content-Encoding (Section 6.5) header fields. Although the value Content-Encoding (Section 6.5) header fields. Although the value
describes the content-coding, what is more important is that it describes the content-coding, what is more important is that it
indicates what decoding mechanism will be required to remove the indicates what decoding mechanism will be required to remove the
encoding. encoding.
compress compress
See Section 4.2.1 of [Part1].
See Section 5.1.2.1 of [Part1].
deflate deflate
See Section 5.1.2.2 of [Part1]. See Section 4.2.2 of [Part1].
gzip gzip
See Section 5.1.2.3 of [Part1]. See Section 4.2.3 of [Part1].
2.2.1. Content Coding Registry 2.2.1. Content Coding Registry
The HTTP Content Coding Registry defines the name space for the The HTTP Content Coding Registry defines the name space for the
content coding names. content coding names.
Registrations MUST include the following fields: Registrations MUST include the following fields:
o Name o Name
o Description o Description
o Pointer to specification text o Pointer to specification text
Names of content codings MUST NOT overlap with names of transfer Names of content codings MUST NOT overlap with names of transfer
codings (Section 5.1 of [Part1]), unless the encoding transformation codings (Section 4 of [Part1]), unless the encoding transformation is
is identical (as it is the case for the compression codings defined identical (as is the case for the compression codings defined in
in Section 5.1.2 of [Part1]). Section 4.2 of [Part1]).
Values to be added to this name space require a specification (see Values to be added to this name space require IETF Review (see
"Specification Required" in Section 4.1 of [RFC5226]), and MUST Section 4.1 of [RFC5226]), and MUST conform to the purpose of content
conform to the purpose of content coding defined in this section. coding defined in this section.
The registry itself is maintained at The registry itself is maintained at
<http://www.iana.org/assignments/http-parameters>. <http://www.iana.org/assignments/http-parameters>.
2.3. Media Types 2.3. Media Types
HTTP uses Internet Media Types [RFC2046] in the Content-Type HTTP uses Internet Media Types [RFC2046] in the Content-Type
(Section 6.8) and Accept (Section 6.1) header fields in order to (Section 6.8) and Accept (Section 6.1) header fields in order to
provide open and extensible data typing and type negotiation. provide open and extensible data typing and type negotiation.
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line breaks applies only to text media in the payload body; a bare CR line breaks applies only to text media in the payload body; a bare CR
or LF MUST NOT be substituted for CRLF within any of the HTTP control or LF MUST NOT be substituted for CRLF within any of the HTTP control
structures (such as header fields and multipart boundaries). structures (such as header fields and multipart boundaries).
If a representation is encoded with a content-coding, the underlying If a representation is encoded with a content-coding, the underlying
data MUST be in a form defined above prior to being encoded. data MUST be in a form defined above prior to being encoded.
2.3.2. Multipart Types 2.3.2. Multipart Types
MIME provides for a number of "multipart" types -- encapsulations of MIME provides for a number of "multipart" types -- encapsulations of
one or more representations within a single message-body. All one or more representations within a single message body. All
multipart types share a common syntax, as defined in Section 5.1.1 of multipart types share a common syntax, as defined in Section 5.1.1 of
[RFC2046], and MUST include a boundary parameter as part of the media [RFC2046], and MUST include a boundary parameter as part of the media
type value. The message body is itself a protocol element and MUST type value. The message body is itself a protocol element and MUST
therefore use only CRLF to represent line breaks between body-parts. therefore use only CRLF to represent line breaks between body-parts.
In general, HTTP treats a multipart message-body no differently than In general, HTTP treats a multipart message body no differently than
any other media type: strictly as payload. HTTP does not use the any other media type: strictly as payload. HTTP does not use the
multipart boundary as an indicator of message-body length. In all multipart boundary as an indicator of message body length. In all
other respects, an HTTP user agent SHOULD follow the same or similar other respects, an HTTP user agent SHOULD follow the same or similar
behavior as a MIME user agent would upon receipt of a multipart type. behavior as a MIME user agent would upon receipt of a multipart type.
The MIME header fields within each body-part of a multipart message- The MIME header fields within each body-part of a multipart message
body do not have any significance to HTTP beyond that defined by body do not have any significance to HTTP beyond that defined by
their MIME semantics. their MIME semantics.
If an application receives an unrecognized multipart subtype, the If an application receives an unrecognized multipart subtype, the
application MUST treat it as being equivalent to "multipart/mixed". application MUST treat it as being equivalent to "multipart/mixed".
Note: The "multipart/form-data" type has been specifically defined Note: The "multipart/form-data" type has been specifically defined
for carrying form data suitable for processing via the POST for carrying form data suitable for processing via the POST
request method, as described in [RFC2388]. request method, as described in [RFC2388].
skipping to change at page 11, line 10 skipping to change at page 11, line 12
en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN
See [RFC5646] for further information. See [RFC5646] for further information.
3. Payload 3. Payload
HTTP messages MAY transfer a payload if not otherwise restricted by HTTP messages MAY transfer a payload if not otherwise restricted by
the request method or response status code. The payload consists of the request method or response status code. The payload consists of
metadata, in the form of header fields, and data, in the form of the metadata, in the form of header fields, and data, in the form of the
sequence of octets in the message-body after any transfer-coding has sequence of octets in the message body after any transfer-coding has
been decoded. been decoded.
A "payload" in HTTP is always a partial or complete representation of A "payload" in HTTP is always a partial or complete representation of
some resource. We use separate terms for payload and representation some resource. We use separate terms for payload and representation
because some messages contain only the associated representation's because some messages contain only the associated representation's
header fields (e.g., responses to HEAD) or only some part(s) of the header fields (e.g., responses to HEAD) or only some part(s) of the
representation (e.g., the 206 status code). representation (e.g., the 206 status code).
3.1. Payload Header Fields 3.1. Payload Header Fields
HTTP header fields that specifically define the payload, rather than HTTP header fields that specifically define the payload, rather than
the associated representation, are referred to as "payload header the associated representation, are referred to as "payload header
fields". The following payload header fields are defined by fields". The following payload header fields are defined by
HTTP/1.1: HTTP/1.1:
+-------------------+------------------------+ +-------------------+--------------------------+
| Header Field Name | Defined in... | | Header Field Name | Defined in... |
+-------------------+------------------------+ +-------------------+--------------------------+
| Content-Length | Section 8.2 of [Part1] | | Content-Length | Section 3.3.2 of [Part1] |
| Content-Range | Section 5.2 of [Part5] | | Content-Range | Section 5.2 of [Part5] |
+-------------------+------------------------+ +-------------------+--------------------------+
3.2. Payload Body 3.2. Payload Body
A payload body is only present in a message when a message-body is A payload body is only present in a message when a message body is
present, as described in Section 3.3 of [Part1]. The payload body is present, as described in Section 3.3 of [Part1]. The payload body is
obtained from the message-body by decoding any Transfer-Encoding that obtained from the message body by decoding any Transfer-Encoding that
might have been applied to ensure safe and proper transfer of the might have been applied to ensure safe and proper transfer of the
message. message.
4. Representation 4. Representation
A "representation" is information in a format that can be readily A "representation" is information in a format that can be readily
communicated from one party to another. A resource representation is communicated from one party to another. A resource representation is
information that reflects the state of that resource, as observed at information that reflects the state of that resource, as observed at
some point in the past (e.g., in a response to GET) or to be desired some point in the past (e.g., in a response to GET) or to be desired
at some point in the future (e.g., in a PUT request). at some point in the future (e.g., in a PUT request).
skipping to change at page 12, line 18 skipping to change at page 12, line 20
contrast, contains either a representation that describes the contrast, contains either a representation that describes the
successful action or a representation of the target resource, with successful action or a representation of the target resource, with
the latter indicated by a Content-Location header field with the same the latter indicated by a Content-Location header field with the same
value as the effective request URI. Likewise, response messages with value as the effective request URI. Likewise, response messages with
an error status code usually contain a representation that describes an error status code usually contain a representation that describes
the error and what next steps are suggested for resolving it. the error and what next steps are suggested for resolving it.
4.1. Representation Header Fields 4.1. Representation Header Fields
Representation header fields define metadata about the representation Representation header fields define metadata about the representation
data enclosed in the message-body or, if no message-body is present, data enclosed in the message body or, if no message body is present,
about the representation that would have been transferred in a 200 about the representation that would have been transferred in a 200
response to a simultaneous GET request with the same effective response to a simultaneous GET request with the same effective
request URI. request URI.
The following header fields are defined as representation metadata: The following header fields are defined as representation metadata:
+-------------------+------------------------+ +-------------------+------------------------+
| Header Field Name | Defined in... | | Header Field Name | Defined in... |
+-------------------+------------------------+ +-------------------+------------------------+
| Content-Encoding | Section 6.5 | | Content-Encoding | Section 6.5 |
| Content-Language | Section 6.6 | | Content-Language | Section 6.6 |
| Content-Location | Section 6.7 | | Content-Location | Section 6.7 |
| Content-Type | Section 6.8 | | Content-Type | Section 6.8 |
| Expires | Section 3.3 of [Part6] | | Expires | Section 3.3 of [Part6] |
+-------------------+------------------------+
Additional header fields define metadata about the selected
representation, which might differ from the representation included
in the message for responses to some state-changing methods. The
following header fields are defined as selected representation
metadata:
+-------------------+------------------------+
| Header Field Name | Defined in... |
+-------------------+------------------------+
| ETag | Section 2.3 of [Part4] |
| Last-Modified | Section 2.2 of [Part4] | | Last-Modified | Section 2.2 of [Part4] |
+-------------------+------------------------+ +-------------------+------------------------+
4.2. Representation Data 4.2. Representation Data
The representation body associated with an HTTP message is either The representation body associated with an HTTP message is either
provided as the payload body of the message or referred to by the provided as the payload body of the message or referred to by the
message semantics and the effective request URI. The representation message semantics and the effective request URI. The representation
data is in a format and encoding defined by the representation data is in a format and encoding defined by the representation
metadata header fields. metadata header fields.
skipping to change at page 15, line 17 skipping to change at page 15, line 32
of responses have multiple representations) and a potential of responses have multiple representations) and a potential
violation of the user's privacy. violation of the user's privacy.
3. It complicates the implementation of an origin server and the 3. It complicates the implementation of an origin server and the
algorithms for generating responses to a request. algorithms for generating responses to a request.
4. It might limit a public cache's ability to use the same response 4. It might limit a public cache's ability to use the same response
for multiple user's requests. for multiple user's requests.
Server-driven negotiation allows the user agent to specify its Server-driven negotiation allows the user agent to specify its
preferences, but it cannot expect responses to always honour them. preferences, but it cannot expect responses to always honor them.
For example, the origin server might not implement server-driven For example, the origin server might not implement server-driven
negotiation, or it might decide that sending a response that doesn't negotiation, or it might decide that sending a response that doesn't
conform to them is better than sending a 406 (Not Acceptable) conform to them is better than sending a 406 (Not Acceptable)
response. response.
Many of the mechanisms for expressing preferences use quality values Many of the mechanisms for expressing preferences use quality values
to declare relative preference. See Section 5.3 of [Part1] for more to declare relative preference. See Section 4.3.1 of [Part1] for
information. more information.
HTTP/1.1 includes the following header fields for enabling server- HTTP/1.1 includes the following header fields for enabling server-
driven negotiation through description of user agent capabilities and driven negotiation through description of user agent capabilities and
user preferences: Accept (Section 6.1), Accept-Charset (Section 6.2), user preferences: Accept (Section 6.1), Accept-Charset (Section 6.2),
Accept-Encoding (Section 6.3), Accept-Language (Section 6.4), and Accept-Encoding (Section 6.3), Accept-Language (Section 6.4), and
User-Agent (Section 9.10 of [Part2]). However, an origin server is User-Agent (Section 10.10 of [Part2]). However, an origin server is
not limited to these dimensions and MAY vary the response based on not limited to these dimensions and MAY vary the response based on
any aspect of the request, including aspects of the connection (e.g., any aspect of the request, including aspects of the connection (e.g.,
IP address) or information within extension header fields not defined IP address) or information within extension header fields not defined
by this specification. by this specification.
Note: In practice, User-Agent based negotiation is fragile, Note: In practice, User-Agent based negotiation is fragile,
because new clients might not be recognized. because new clients might not be recognized.
The Vary header field (Section 3.5 of [Part6]) can be used to express The Vary header field (Section 3.5 of [Part6]) can be used to express
the parameters the server uses to select a representation that is the parameters the server uses to select a representation that is
skipping to change at page 17, line 10 skipping to change at page 17, line 26
The asterisk "*" character is used to group media types into ranges, The asterisk "*" character is used to group media types into ranges,
with "*/*" indicating all media types and "type/*" indicating all with "*/*" indicating all media types and "type/*" indicating all
subtypes of that type. The media-range MAY include media type subtypes of that type. The media-range MAY include media type
parameters that are applicable to that range. parameters that are applicable to that range.
Each media-range MAY be followed by one or more accept-params, Each media-range MAY be followed by one or more accept-params,
beginning with the "q" parameter for indicating a relative quality beginning with the "q" parameter for indicating a relative quality
factor. The first "q" parameter (if any) separates the media-range factor. The first "q" parameter (if any) separates the media-range
parameter(s) from the accept-params. Quality factors allow the user parameter(s) from the accept-params. Quality factors allow the user
or user agent to indicate the relative degree of preference for that or user agent to indicate the relative degree of preference for that
media-range, using the qvalue scale from 0 to 1 (Section 5.3 of media-range, using the qvalue scale from 0 to 1 (Section 4.3.1 of
[Part1]). The default value is q=1. [Part1]). The default value is q=1.
Note: Use of the "q" parameter name to separate media type Note: Use of the "q" parameter name to separate media type
parameters from Accept extension parameters is due to historical parameters from Accept extension parameters is due to historical
practice. Although this prevents any media type parameter named practice. Although this prevents any media type parameter named
"q" from being used with a media range, such an event is believed "q" from being used with a media range, such an event is believed
to be unlikely given the lack of any "q" parameters in the IANA to be unlikely given the lack of any "q" parameters in the IANA
media type registry and the rare usage of any media type media type registry and the rare usage of any media type
parameters in Accept. Future media types are discouraged from parameters in Accept. Future media types are discouraged from
registering any parameter named "q". registering any parameter named "q".
skipping to change at page 20, line 14 skipping to change at page 20, line 30
field. field.
2. If the representation has no content-coding, then it is 2. If the representation has no content-coding, then it is
acceptable by default unless specifically excluded by the Accept- acceptable by default unless specifically excluded by the Accept-
Encoding field stating either "identity;q=0" or "*;q=0" without a Encoding field stating either "identity;q=0" or "*;q=0" without a
more specific entry for "identity". more specific entry for "identity".
3. If the representation's content-coding is one of the content- 3. If the representation's content-coding is one of the content-
codings listed in the Accept-Encoding field, then it is codings listed in the Accept-Encoding field, then it is
acceptable unless it is accompanied by a qvalue of 0. (As acceptable unless it is accompanied by a qvalue of 0. (As
defined in Section 5.3 of [Part1], a qvalue of 0 means "not defined in Section 4.3.1 of [Part1], a qvalue of 0 means "not
acceptable".) acceptable".)
4. If multiple content-codings are acceptable, then the acceptable 4. If multiple content-codings are acceptable, then the acceptable
content-coding with the highest non-zero qvalue is preferred. content-coding with the highest non-zero qvalue is preferred.
An Accept-Encoding header field with a combined field-value that is An Accept-Encoding header field with a combined field-value that is
empty implies that the user agent does not want any content-coding in empty implies that the user agent does not want any content-coding in
response. If an Accept-Encoding header field is present in a request response. If an Accept-Encoding header field is present in a request
and none of the available representations for the response have a and none of the available representations for the response have a
content-coding that is listed as acceptable, the origin server SHOULD content-coding that is listed as acceptable, the origin server SHOULD
skipping to change at page 23, line 39 skipping to change at page 24, line 6
The "Content-Location" header field supplies a URI that can be used The "Content-Location" header field supplies a URI that can be used
as a specific identifier for the representation in this message. In as a specific identifier for the representation in this message. In
other words, if one were to perform a GET on this URI at the time of other words, if one were to perform a GET on this URI at the time of
this message's generation, then a 200 response would contain the same this message's generation, then a 200 response would contain the same
representation that is enclosed as payload in this message. representation that is enclosed as payload in this message.
Content-Location = absolute-URI / partial-URI Content-Location = absolute-URI / partial-URI
The Content-Location value is not a replacement for the effective The Content-Location value is not a replacement for the effective
Request URI (Section 4.3 of [Part1]). It is representation metadata. Request URI (Section 5.5 of [Part1]). It is representation metadata.
It has the same syntax and semantics as the header field of the same It has the same syntax and semantics as the header field of the same
name defined for MIME body parts in Section 4 of [RFC2557]. However, name defined for MIME body parts in Section 4 of [RFC2557]. However,
its appearance in an HTTP message has some special implications for its appearance in an HTTP message has some special implications for
HTTP recipients. HTTP recipients.
If Content-Location is included in a response message and its value If Content-Location is included in a response message and its value
is the same as the effective request URI, then the response payload is the same as the effective request URI, then the response payload
SHOULD be considered the current representation of that resource. SHOULD be considered a current representation of that resource. For
For a GET or HEAD request, this is the same as the default semantics a GET or HEAD request, this is the same as the default semantics when
when no Content-Location is provided by the server. For a state- no Content-Location is provided by the server. For a state-changing
changing request like PUT or POST, it implies that the server's request like PUT or POST, it implies that the server's response
response contains the new representation of that resource, thereby contains the new representation of that resource, thereby
distinguishing it from representations that might only report about distinguishing it from representations that might only report about
the action (e.g., "It worked!"). This allows authoring applications the action (e.g., "It worked!"). This allows authoring applications
to update their local copies without the need for a subsequent GET to update their local copies without the need for a subsequent GET
request. request.
If Content-Location is included in a response message and its value If Content-Location is included in a response message and its value
differs from the effective request URI, then the origin server is differs from the effective request URI, then the origin server is
informing recipients that this representation has its own, presumably informing recipients that this representation has its own, presumably
more specific, identifier. For a GET or HEAD request, this is an more specific, identifier. For a GET or HEAD request, this is an
indication that the effective request URI identifies a resource that indication that the effective request URI identifies a resource that
is subject to content negotiation and the representation selected for is subject to content negotiation and the selected representation for
this response can also be found at the identified URI. For other this response can also be found at the identified URI. For other
methods, such a Content-Location indicates that this representation methods, such a Content-Location indicates that this representation
contains a report on the action's status and the same report is contains a report on the action's status and the same report is
available (for future access with GET) at the given URI. For available (for future access with GET) at the given URI. For
example, a purchase transaction made via a POST request might include example, a purchase transaction made via a POST request might include
a receipt document as the payload of the 200 response; the Content- a receipt document as the payload of the 200 response; the Content-
Location value provides an identifier for retrieving a copy of that Location value provides an identifier for retrieving a copy of that
same receipt in the future. same receipt in the future.
If Content-Location is included in a request message, then it MAY be If Content-Location is included in a request message, then it MAY be
skipping to change at page 26, line 7 skipping to change at page 26, line 31
7.2. Content Coding Registry 7.2. Content Coding Registry
The registration procedure for HTTP Content Codings is now defined by The registration procedure for HTTP Content Codings is now defined by
Section 2.2.1 of this document. Section 2.2.1 of this document.
The HTTP Content Codings Registry located at The HTTP Content Codings Registry located at
<http://www.iana.org/assignments/http-parameters> shall be updated <http://www.iana.org/assignments/http-parameters> shall be updated
with the registration below: with the registration below:
+----------+-----------------------------------------+--------------+ +----------+------------------------------------------+-------------+
| Name | Description | Reference | | Name | Description | Reference |
+----------+-----------------------------------------+--------------+ +----------+------------------------------------------+-------------+
| compress | UNIX "compress" program method | Section | | compress | UNIX "compress" program method | Section |
| | | 5.1.2.1 of | | | | 4.2.1 of |
| | | [Part1] | | | | [Part1] |
| deflate | "deflate" compression mechanism | Section | | deflate | "deflate" compression mechanism | Section |
| | ([RFC1951]) used inside the "zlib" data | 5.1.2.2 of | | | ([RFC1951]) used inside the "zlib" data | 4.2.2 of |
| | format ([RFC1950]) | [Part1] | | | format ([RFC1950]) | [Part1] |
| gzip | Same as GNU zip [RFC1952] | Section | | gzip | Same as GNU zip [RFC1952] | Section |
| | | 5.1.2.3 of | | | | 4.2.3 of |
| | | [Part1] | | | | [Part1] |
| identity | reserved (synonym for "no encoding" in | Section 6.3 | | identity | reserved (synonym for "no encoding" in | Section 6.3 |
| | Accept-Encoding header field) | | | | Accept-Encoding header field) | |
+----------+-----------------------------------------+--------------+ +----------+------------------------------------------+-------------+
8. Security Considerations 8. Security Considerations
This section is meant to inform application developers, information This section is meant to inform application developers, information
providers, and users of the security limitations in HTTP/1.1 as providers, and users of the security limitations in HTTP/1.1 as
described by this document. The discussion does not include described by this document. The discussion does not include
definitive solutions to the problems revealed, though it does make definitive solutions to the problems revealed, though it does make
some suggestions for reducing security risks. some suggestions for reducing security risks.
8.1. Privacy Issues Connected to Accept Header Fields 8.1. Privacy Issues Connected to Accept Header Fields
Accept headers fields can reveal information about the user to all Accept header fields can reveal information about the user to all
servers which are accessed. The Accept-Language header field in servers which are accessed. The Accept-Language header field in
particular can reveal information the user would consider to be of a particular can reveal information the user would consider to be of a
private nature, because the understanding of particular languages is private nature, because the understanding of particular languages is
often strongly correlated to the membership of a particular ethnic often strongly correlated to the membership of a particular ethnic
group. User agents which offer the option to configure the contents group. User agents which offer the option to configure the contents
of an Accept-Language header field to be sent in every request are of an Accept-Language header field to be sent in every request are
strongly encouraged to let the configuration process include a strongly encouraged to let the configuration process include a
message which makes the user aware of the loss of privacy involved. message which makes the user aware of the loss of privacy involved.
An approach that limits the loss of privacy would be for a user agent An approach that limits the loss of privacy would be for a user agent
skipping to change at page 27, line 20 skipping to change at page 27, line 43
identifier. In environments where proxies are used to enhance identifier. In environments where proxies are used to enhance
privacy, user agents ought to be conservative in offering accept privacy, user agents ought to be conservative in offering accept
header configuration options to end users. As an extreme privacy header configuration options to end users. As an extreme privacy
measure, proxies could filter the accept header fields in relayed measure, proxies could filter the accept header fields in relayed
requests. General purpose user agents which provide a high degree of requests. General purpose user agents which provide a high degree of
header configurability SHOULD warn users about the loss of privacy header configurability SHOULD warn users about the loss of privacy
which can be involved. which can be involved.
9. Acknowledgments 9. Acknowledgments
See Section 11 of [Part1]. See Section 9 of [Part1].
10. References 10. References
10.1. Normative References 10.1. Normative References
[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part1] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., "HTTP/1.1, part 1: URIs, Connections, and Message
and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections, Parsing", draft-ietf-httpbis-p1-messaging-19 (work in
and Message Parsing", draft-ietf-httpbis-p1-messaging-18 progress), March 2012.
(work in progress), January 2012.
[Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part2] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., "HTTP/1.1, part 2: Message Semantics",
and J. Reschke, Ed., "HTTP/1.1, part 2: Message draft-ietf-httpbis-p2-semantics-19 (work in progress),
Semantics", draft-ietf-httpbis-p2-semantics-18 (work in March 2012.
progress), January 2012.
[Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part4] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., "HTTP/1.1, part 4: Conditional Requests",
and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional draft-ietf-httpbis-p4-conditional-19 (work in progress),
Requests", draft-ietf-httpbis-p4-conditional-18 (work in March 2012.
progress), January 2012.
[Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part5] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., "HTTP/1.1, part 5: Range Requests and Partial Responses",
and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and draft-ietf-httpbis-p5-range-19 (work in progress),
Partial Responses", draft-ietf-httpbis-p5-range-18 (work March 2012.
in progress), January 2012.
[Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., [Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed.,
Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",
Nottingham, M., Ed., and J. Reschke, Ed., "HTTP/1.1, part draft-ietf-httpbis-p6-cache-19 (work in progress),
6: Caching", draft-ietf-httpbis-p6-cache-18 (work in March 2012.
progress), January 2012.
[RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format [RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format
Specification version 3.3", RFC 1950, May 1996. Specification version 3.3", RFC 1950, May 1996.
[RFC1951] Deutsch, P., "DEFLATE Compressed Data Format Specification [RFC1951] Deutsch, P., "DEFLATE Compressed Data Format Specification
version 1.3", RFC 1951, May 1996. version 1.3", RFC 1951, May 1996.
[RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and G. [RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and G.
Randers-Pehrson, "GZIP file format specification version Randers-Pehrson, "GZIP file format specification version
4.3", RFC 1952, May 1996. 4.3", RFC 1952, May 1996.
skipping to change at page 30, line 4 skipping to change at page 30, line 21
RFC 6151, March 2011. RFC 6151, March 2011.
[RFC6266] Reschke, J., "Use of the Content-Disposition Header Field [RFC6266] Reschke, J., "Use of the Content-Disposition Header Field
in the Hypertext Transfer Protocol (HTTP)", RFC 6266, in the Hypertext Transfer Protocol (HTTP)", RFC 6266,
June 2011. June 2011.
Appendix A. Differences between HTTP and MIME Appendix A. Differences between HTTP and MIME
HTTP/1.1 uses many of the constructs defined for Internet Mail HTTP/1.1 uses many of the constructs defined for Internet Mail
([RFC5322]) and the Multipurpose Internet Mail Extensions (MIME ([RFC5322]) and the Multipurpose Internet Mail Extensions (MIME
[RFC2045]) to allow a message body to be transmitted in an open
[RFC2045]) to allow a message-body to be transmitted in an open
variety of representations and with extensible mechanisms. However, variety of representations and with extensible mechanisms. However,
RFC 2045 discusses mail, and HTTP has a few features that are RFC 2045 discusses mail, and HTTP has a few features that are
different from those described in MIME. These differences were different from those described in MIME. These differences were
carefully chosen to optimize performance over binary connections, to carefully chosen to optimize performance over binary connections, to
allow greater freedom in the use of new media types, to make date allow greater freedom in the use of new media types, to make date
comparisons easier, and to acknowledge the practice of some early comparisons easier, and to acknowledge the practice of some early
HTTP servers and clients. HTTP servers and clients.
This appendix describes specific areas where HTTP differs from MIME. This appendix describes specific areas where HTTP differs from MIME.
Proxies and gateways to strict MIME environments SHOULD be aware of Proxies and gateways to strict MIME environments SHOULD be aware of
skipping to change at page 30, line 27 skipping to change at page 30, line 43
necessary. Proxies and gateways from MIME environments to HTTP also necessary. Proxies and gateways from MIME environments to HTTP also
need to be aware of the differences because some conversions might be need to be aware of the differences because some conversions might be
required. required.
A.1. MIME-Version A.1. MIME-Version
HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages
MAY include a single MIME-Version header field to indicate what MAY include a single MIME-Version header field to indicate what
version of the MIME protocol was used to construct the message. Use version of the MIME protocol was used to construct the message. Use
of the MIME-Version header field indicates that the message is in of the MIME-Version header field indicates that the message is in
full compliance with the MIME protocol (as defined in [RFC2045]). full conformance with the MIME protocol (as defined in [RFC2045]).
Proxies/gateways are responsible for ensuring full compliance (where Proxies/gateways are responsible for ensuring full conformance (where
possible) when exporting HTTP messages to strict MIME environments. possible) when exporting HTTP messages to strict MIME environments.
MIME-Version = 1*DIGIT "." 1*DIGIT MIME-Version = 1*DIGIT "." 1*DIGIT
MIME version "1.0" is the default for use in HTTP/1.1. However, MIME version "1.0" is the default for use in HTTP/1.1. However,
HTTP/1.1 message parsing and semantics are defined by this document HTTP/1.1 message parsing and semantics are defined by this document
and not the MIME specification. and not the MIME specification.
A.2. Conversion to Canonical Form A.2. Conversion to Canonical Form
skipping to change at page 32, line 7 skipping to change at page 32, line 22
Proxies and gateways from HTTP to MIME-compliant protocols are Proxies and gateways from HTTP to MIME-compliant protocols are
responsible for ensuring that the message is in the correct format responsible for ensuring that the message is in the correct format
and encoding for safe transport on that protocol, where "safe and encoding for safe transport on that protocol, where "safe
transport" is defined by the limitations of the protocol being used. transport" is defined by the limitations of the protocol being used.
Such a proxy or gateway SHOULD label the data with an appropriate Such a proxy or gateway SHOULD label the data with an appropriate
Content-Transfer-Encoding if doing so will improve the likelihood of Content-Transfer-Encoding if doing so will improve the likelihood of
safe transport over the destination protocol. safe transport over the destination protocol.
A.6. Introduction of Transfer-Encoding A.6. Introduction of Transfer-Encoding
HTTP/1.1 introduces the Transfer-Encoding header field (Section 8.6 HTTP/1.1 introduces the Transfer-Encoding header field (Section 3.3.1
of [Part1]). Proxies/gateways MUST remove any transfer-coding prior of [Part1]). Proxies/gateways MUST remove any transfer-coding prior
to forwarding a message via a MIME-compliant protocol. to forwarding a message via a MIME-compliant protocol.
A.7. MHTML and Line Length Limitations A.7. MHTML and Line Length Limitations
HTTP implementations which share code with MHTML [RFC2557] HTTP implementations which share code with MHTML [RFC2557]
implementations need to be aware of MIME line length limitations. implementations need to be aware of MIME line length limitations.
Since HTTP does not have this limitation, HTTP does not fold long Since HTTP does not have this limitation, HTTP does not fold long
lines. MHTML messages being transported by HTTP follow all lines. MHTML messages being transported by HTTP follow all
conventions of MHTML, including line length limitations and folding, conventions of MHTML, including line length limitations and folding,
skipping to change at page 32, line 41 skipping to change at page 33, line 9
the base HTTP/1.1 specification. the base HTTP/1.1 specification.
A number of other header fields, such as Content-Disposition and A number of other header fields, such as Content-Disposition and
Title, from SMTP and MIME are also often implemented (see [RFC6266] Title, from SMTP and MIME are also often implemented (see [RFC6266]
and [RFC2076]). and [RFC2076]).
Appendix C. Changes from RFC 2616 Appendix C. Changes from RFC 2616
Clarify contexts that charset is used in. (Section 2.1) Clarify contexts that charset is used in. (Section 2.1)
Registration of Content Codings now requires IETF Review
(Section 2.2.1)
Remove the default character encoding for text media types; the Remove the default character encoding for text media types; the
default now is whatever the media type definition says. default now is whatever the media type definition says.
(Section 2.3.1) (Section 2.3.1)
Change ABNF productions for header fields to only define the field Change ABNF productions for header fields to only define the field
value. (Section 6) value. (Section 6)
Remove definition of Content-MD5 header field because it was Remove definition of Content-MD5 header field because it was
inconsistently implemented with respect to partial responses, and inconsistently implemented with respect to partial responses, and
also because of known deficiencies in the hash algorithm itself (see also because of known deficiencies in the hash algorithm itself (see
skipping to change at page 33, line 4 skipping to change at page 33, line 23
default now is whatever the media type definition says. default now is whatever the media type definition says.
(Section 2.3.1) (Section 2.3.1)
Change ABNF productions for header fields to only define the field Change ABNF productions for header fields to only define the field
value. (Section 6) value. (Section 6)
Remove definition of Content-MD5 header field because it was Remove definition of Content-MD5 header field because it was
inconsistently implemented with respect to partial responses, and inconsistently implemented with respect to partial responses, and
also because of known deficiencies in the hash algorithm itself (see also because of known deficiencies in the hash algorithm itself (see
[RFC6151] for details). (Section 6) [RFC6151] for details). (Section 6)
Remove ISO-8859-1 special-casing in Accept-Charset. (Section 6.2) Remove ISO-8859-1 special-casing in Accept-Charset. (Section 6.2)
Remove base URI setting semantics for Content-Location due to poor Remove base URI setting semantics for Content-Location due to poor
implementation support, which was caused by too many broken servers implementation support, which was caused by too many broken servers
emitting bogus Content-Location header fields, and also the emitting bogus Content-Location header fields, and also the
potentially undesirable effect of potentially breaking relative links potentially undesirable effect of potentially breaking relative links
in content-negotiated resources. (Section 6.7) in content-negotiated resources. (Section 6.7)
Remove discussion of Content-Disposition header field, it is now
defined by [RFC6266]. (Appendix B)
Remove reference to non-existant identity transfer-coding value Remove reference to non-existant identity transfer-coding value
tokens. (Appendix A.5) tokens. (Appendix A.5)
Remove discussion of Content-Disposition header field, it is now
defined by [RFC6266]. (Appendix B)
Appendix D. Collected ABNF Appendix D. Collected ABNF
Accept = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [ Accept = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [
OWS media-range [ accept-params ] ] ) ] OWS media-range [ accept-params ] ] ) ]
Accept-Charset = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q=" Accept-Charset = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q="
qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q=" qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q="
qvalue ] ] ) qvalue ] ] )
Accept-Encoding = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) ) Accept-Encoding = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) )
*( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ] *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ]
Accept-Language = *( "," OWS ) language-range [ OWS ";" OWS "q=" Accept-Language = *( "," OWS ) language-range [ OWS ";" OWS "q="
skipping to change at page 33, line 33 skipping to change at page 34, line 4
qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q=" qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q="
qvalue ] ] ) qvalue ] ] )
Accept-Encoding = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) ) Accept-Encoding = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) )
*( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ] *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ]
Accept-Language = *( "," OWS ) language-range [ OWS ";" OWS "q=" Accept-Language = *( "," OWS ) language-range [ OWS ";" OWS "q="
qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ] qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ]
] ) ] )
Content-Encoding = *( "," OWS ) content-coding *( OWS "," [ OWS Content-Encoding = *( "," OWS ) content-coding *( OWS "," [ OWS
content-coding ] ) content-coding ] )
Content-Language = *( "," OWS ) language-tag *( OWS "," [ OWS Content-Language = *( "," OWS ) language-tag *( OWS "," [ OWS
language-tag ] ) language-tag ] )
Content-Location = absolute-URI / partial-URI Content-Location = absolute-URI / partial-URI
Content-Type = media-type Content-Type = media-type
MIME-Version = 1*DIGIT "." 1*DIGIT MIME-Version = 1*DIGIT "." 1*DIGIT
OWS = <OWS, defined in [Part1], Section 1.2.2> OWS = <OWS, defined in [Part1], Section 3.2.1>
absolute-URI = <absolute-URI, defined in [Part1], Section 2.7> absolute-URI = <absolute-URI, defined in [Part1], Section 2.7>
accept-ext = OWS ";" OWS token [ "=" word ] accept-ext = OWS ";" OWS token [ "=" word ]
accept-params = OWS ";" OWS "q=" qvalue *accept-ext accept-params = OWS ";" OWS "q=" qvalue *accept-ext
attribute = token attribute = token
charset = token charset = token
codings = content-coding / "identity" / "*" codings = content-coding / "identity" / "*"
content-coding = token content-coding = token
language-range = <language-range, defined in [RFC4647], Section 2.1> language-range = <language-range, defined in [RFC4647], Section 2.1>
language-tag = <Language-Tag, defined in [RFC5646], Section 2.1> language-tag = <Language-Tag, defined in [RFC5646], Section 2.1>
media-range = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS media-range = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS
";" OWS parameter ) ";" OWS parameter )
media-type = type "/" subtype *( OWS ";" OWS parameter ) media-type = type "/" subtype *( OWS ";" OWS parameter )
parameter = attribute "=" value parameter = attribute "=" value
partial-URI = <partial-URI, defined in [Part1], Section 2.7> partial-URI = <partial-URI, defined in [Part1], Section 2.7>
qvalue = <qvalue, defined in [Part1], Section 5.3> qvalue = <qvalue, defined in [Part1], Section 4.3.1>
subtype = token subtype = token
token = <token, defined in [Part1], Section 3.2.3> token = <token, defined in [Part1], Section 3.2.4>
type = token type = token
value = word value = word
word = <word, defined in [Part1], Section 3.2.3> word = <word, defined in [Part1], Section 3.2.4>
ABNF diagnostics: ABNF diagnostics:
; Accept defined but not used ; Accept defined but not used
; Accept-Charset defined but not used ; Accept-Charset defined but not used
; Accept-Encoding defined but not used ; Accept-Encoding defined but not used
; Accept-Language defined but not used ; Accept-Language defined but not used
; Content-Encoding defined but not used ; Content-Encoding defined but not used
; Content-Language defined but not used ; Content-Language defined but not used
; Content-Location defined but not used ; Content-Location defined but not used
; Content-Type defined but not used ; Content-Type defined but not used
skipping to change at page 40, line 42 skipping to change at page 41, line 26
o <http://tools.ietf.org/wg/httpbis/trac/ticket/186>: "Document o <http://tools.ietf.org/wg/httpbis/trac/ticket/186>: "Document
HTTP's error-handling philosophy" HTTP's error-handling philosophy"
E.19. Since draft-ietf-httpbis-p3-payload-17 E.19. Since draft-ietf-httpbis-p3-payload-17
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/323>: "intended o <http://tools.ietf.org/wg/httpbis/trac/ticket/323>: "intended
maturity level vs normative references" maturity level vs normative references"
E.20. Since draft-ietf-httpbis-p3-payload-18
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/330>: "is ETag a
representation header field?"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/338>: "Content-
Location doesn't constrain the cardinality of representations"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/346>: "make IANA
policy definitions consistent"
Index Index
A A
Accept header field 16 Accept header field 16
Accept-Charset header field 18 Accept-Charset header field 19
Accept-Encoding header field 19 Accept-Encoding header field 19
Accept-Language header field 20 Accept-Language header field 21
C C
Coding Format Coding Format
compress 7 compress 7
deflate 7 deflate 8
gzip 8 gzip 8
compress (Coding Format) 7 compress (Coding Format) 7
content negotiation 5 content negotiation 5
Content-Encoding header field 21 Content-Encoding header field 22
Content-Language header field 22 Content-Language header field 23
Content-Location header field 23 Content-Location header field 23
Content-Transfer-Encoding header field 32
Content-Type header field 25 Content-Type header field 25
D D
deflate (Coding Format) 7 deflate (Coding Format) 8
G G
Grammar Grammar
Accept 16 Accept 17
Accept-Charset 18 Accept-Charset 19
Accept-Encoding 19 Accept-Encoding 19
accept-ext 16 accept-ext 17
Accept-Language 20 Accept-Language 21
accept-params 16 accept-params 17
attribute 8 attribute 9
charset 7 charset 7
codings 19 codings 19
content-coding 7 content-coding 7
Content-Encoding 21 Content-Encoding 22
Content-Language 22 Content-Language 23
Content-Location 23 Content-Location 23
Content-Type 25 Content-Type 25
language-range 20 language-range 21
language-tag 10 language-tag 10
media-range 16 media-range 17
media-type 8 media-type 8
MIME-Version 30 MIME-Version 30
parameter 8 parameter 9
subtype 8 subtype 8
type 8 type 8
value 8 value 9
gzip (Coding Format) 8 gzip (Coding Format) 8
H H
Header Fields Header Fields
Accept 16 Accept 16
Accept-Charset 18 Accept-Charset 19
Accept-Encoding 19 Accept-Encoding 19
Accept-Language 20 Accept-Language 21
Content-Encoding 21 Content-Encoding 22
Content-Language 22 Content-Language 23
Content-Location 23 Content-Location 23
Content-Transfer-Encoding 32
Content-Type 25 Content-Type 25
MIME-Version 30 MIME-Version 30
M M
MIME-Version header field 30 MIME-Version header field 30
P P
payload 11 payload 11
R R
representation 11 representation 11
S
selected representation 5
Authors' Addresses Authors' Addresses
Roy T. Fielding (editor) Roy T. Fielding (editor)
Adobe Systems Incorporated Adobe Systems Incorporated
345 Park Ave 345 Park Ave
San Jose, CA 95110 San Jose, CA 95110
USA USA
EMail: fielding@gbiv.com EMail: fielding@gbiv.com
URI: http://roy.gbiv.com/ URI: http://roy.gbiv.com/
Jim Gettys
Alcatel-Lucent Bell Labs
21 Oak Knoll Road
Carlisle, MA 01741
USA
EMail: jg@freedesktop.org
URI: http://gettys.wordpress.com/
Jeffrey C. Mogul
Hewlett-Packard Company
HP Labs, Large Scale Systems Group
1501 Page Mill Road, MS 1177
Palo Alto, CA 94304
USA
EMail: JeffMogul@acm.org
Henrik Frystyk Nielsen
Microsoft Corporation
1 Microsoft Way
Redmond, WA 98052
USA
EMail: henrikn@microsoft.com
Larry Masinter
Adobe Systems Incorporated
345 Park Ave
San Jose, CA 95110
USA
EMail: LMM@acm.org
URI: http://larry.masinter.net/
Paul J. Leach
Microsoft Corporation
1 Microsoft Way
Redmond, WA 98052
EMail: paulle@microsoft.com
Tim Berners-Lee
World Wide Web Consortium
MIT Computer Science and Artificial Intelligence Laboratory
The Stata Center, Building 32
32 Vassar Street
Cambridge, MA 02139
USA
EMail: timbl@w3.org
URI: http://www.w3.org/People/Berners-Lee/
Yves Lafon (editor) Yves Lafon (editor)
World Wide Web Consortium World Wide Web Consortium
W3C / ERCIM W3C / ERCIM
2004, rte des Lucioles 2004, rte des Lucioles
Sophia-Antipolis, AM 06902 Sophia-Antipolis, AM 06902
France France
EMail: ylafon@w3.org EMail: ylafon@w3.org
URI: http://www.raubacapeu.net/people/yves/ URI: http://www.raubacapeu.net/people/yves/
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