draft-ietf-httpbis-p1-messaging-19.txt   draft-ietf-httpbis-p1-messaging-20.txt 
HTTPbis Working Group R. Fielding, Ed. HTTPbis Working Group R. Fielding, Ed.
Internet-Draft Adobe Internet-Draft Adobe
Obsoletes: 2145,2616 (if approved) Y. Lafon, Ed. Obsoletes: 2145,2616 (if approved) Y. Lafon, Ed.
Updates: 2817 (if approved) W3C Updates: 2817 (if approved) W3C
Intended status: Standards Track J. Reschke, Ed. Intended status: Standards Track J. Reschke, Ed.
Expires: September 13, 2012 greenbytes Expires: January 17, 2013 greenbytes
March 12, 2012 July 16, 2012
HTTP/1.1, part 1: URIs, Connections, and Message Parsing HTTP/1.1, part 1: Message Routing and Syntax"
draft-ietf-httpbis-p1-messaging-19 draft-ietf-httpbis-p1-messaging-20
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 1 of the information initiative since 1990. This document provides an
seven-part specification that defines the protocol referred to as overview of HTTP architecture and its associated terminology, defines
"HTTP/1.1" and, taken together, obsoletes RFC 2616 and moves it to the "http" and "https" Uniform Resource Identifier (URI) schemes,
historic status, along with its predecessor RFC 2068. defines the HTTP/1.1 message syntax and parsing requirements, and
describes general security concerns for implementations.
Part 1 provides an overview of HTTP and its associated terminology,
defines the "http" and "https" Uniform Resource Identifier (URI)
schemes, defines the generic message syntax and parsing requirements
for HTTP message frames, and describes general security concerns for
implementations.
This part also obsoletes RFCs 2145 (on HTTP version numbers) and 2817
(on using CONNECT for TLS upgrades) and moves them to historic
status.
Editorial Note (To be removed by RFC Editor) Editorial Note (To be removed by RFC Editor)
Discussion of this draft should take place on the HTTPBIS working Discussion of this draft takes place on the HTTPBIS working group
group mailing list (ietf-http-wg@w3.org), which is archived at 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 C.20. The changes in this draft are summarized in Appendix D.21.
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 September 13, 2012. This Internet-Draft will expire on January 17, 2013.
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
skipping to change at page 3, line 4 skipping to change at page 2, line 43
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1. Requirement Notation . . . . . . . . . . . . . . . . . . . 7 1.1. Requirement Notation . . . . . . . . . . . . . . . . . . . 7
1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 7 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 7
2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 7 2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1. Client/Server Messaging . . . . . . . . . . . . . . . . . 7 2.1. Client/Server Messaging . . . . . . . . . . . . . . . . . 7
2.2. Connections and Transport Independence . . . . . . . . . . 9 2.2. Implementation Diversity . . . . . . . . . . . . . . . . . 9
2.3. Intermediaries . . . . . . . . . . . . . . . . . . . . . . 9 2.3. Connections and Transport Independence . . . . . . . . . . 10
2.4. Caches . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.4. Intermediaries . . . . . . . . . . . . . . . . . . . . . . 10
2.5. Conformance and Error Handling . . . . . . . . . . . . . . 12 2.5. Caches . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.6. Protocol Versioning . . . . . . . . . . . . . . . . . . . 13 2.6. Conformance and Error Handling . . . . . . . . . . . . . . 13
2.7. Uniform Resource Identifiers . . . . . . . . . . . . . . . 15 2.7. Protocol Versioning . . . . . . . . . . . . . . . . . . . 14
2.7.1. http URI scheme . . . . . . . . . . . . . . . . . . . 16 2.8. Uniform Resource Identifiers . . . . . . . . . . . . . . . 16
2.7.2. https URI scheme . . . . . . . . . . . . . . . . . . . 17 2.8.1. http URI scheme . . . . . . . . . . . . . . . . . . . 17
2.7.3. http and https URI Normalization and Comparison . . . 18 2.8.2. https URI scheme . . . . . . . . . . . . . . . . . . . 18
3. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 19 2.8.3. http and https URI Normalization and Comparison . . . 19
3.1. Start Line . . . . . . . . . . . . . . . . . . . . . . . . 19 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1.1. Request Line . . . . . . . . . . . . . . . . . . . . . 20 3.1. Start Line . . . . . . . . . . . . . . . . . . . . . . . . 20
3.1.2. Status Line . . . . . . . . . . . . . . . . . . . . . 21 3.1.1. Request Line . . . . . . . . . . . . . . . . . . . . . 21
3.2. Header Fields . . . . . . . . . . . . . . . . . . . . . . 21 3.1.2. Status Line . . . . . . . . . . . . . . . . . . . . . 22
3.2.1. Whitespace . . . . . . . . . . . . . . . . . . . . . . 23 3.2. Header Fields . . . . . . . . . . . . . . . . . . . . . . 23
3.2.2. Field Parsing . . . . . . . . . . . . . . . . . . . . 23 3.2.1. Whitespace . . . . . . . . . . . . . . . . . . . . . . 24
3.2.3. Field Length . . . . . . . . . . . . . . . . . . . . . 24 3.2.2. Field Parsing . . . . . . . . . . . . . . . . . . . . 25
3.2.4. Field value components . . . . . . . . . . . . . . . . 25 3.2.3. Field Length . . . . . . . . . . . . . . . . . . . . . 25
3.2.5. ABNF list extension: #rule . . . . . . . . . . . . . . 26 3.2.4. Field value components . . . . . . . . . . . . . . . . 26
3.3. Message Body . . . . . . . . . . . . . . . . . . . . . . . 27 3.3. Message Body . . . . . . . . . . . . . . . . . . . . . . . 27
3.3.1. Transfer-Encoding . . . . . . . . . . . . . . . . . . 27 3.3.1. Transfer-Encoding . . . . . . . . . . . . . . . . . . 27
3.3.2. Content-Length . . . . . . . . . . . . . . . . . . . . 29 3.3.2. Content-Length . . . . . . . . . . . . . . . . . . . . 29
3.3.3. Message Body Length . . . . . . . . . . . . . . . . . 30 3.3.3. Message Body Length . . . . . . . . . . . . . . . . . 30
3.4. Handling Incomplete Messages . . . . . . . . . . . . . . . 32 3.4. Handling Incomplete Messages . . . . . . . . . . . . . . . 32
3.5. Message Parsing Robustness . . . . . . . . . . . . . . . . 33 3.5. Message Parsing Robustness . . . . . . . . . . . . . . . . 33
4. Transfer Codings . . . . . . . . . . . . . . . . . . . . . . . 33 4. Transfer Codings . . . . . . . . . . . . . . . . . . . . . . . 33
4.1. Chunked Transfer Coding . . . . . . . . . . . . . . . . . 34 4.1. Chunked Transfer Coding . . . . . . . . . . . . . . . . . 34
4.2. Compression Codings . . . . . . . . . . . . . . . . . . . 36 4.2. Compression Codings . . . . . . . . . . . . . . . . . . . 36
4.2.1. Compress Coding . . . . . . . . . . . . . . . . . . . 36 4.2.1. Compress Coding . . . . . . . . . . . . . . . . . . . 36
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5.6. Intermediary Forwarding . . . . . . . . . . . . . . . . . 44 5.6. Intermediary Forwarding . . . . . . . . . . . . . . . . . 44
5.6.1. End-to-end and Hop-by-hop Header Fields . . . . . . . 45 5.6.1. End-to-end and Hop-by-hop Header Fields . . . . . . . 45
5.6.2. Non-modifiable Header Fields . . . . . . . . . . . . . 46 5.6.2. Non-modifiable Header Fields . . . . . . . . . . . . . 46
5.7. Associating a Response to a Request . . . . . . . . . . . 47 5.7. Associating a Response to a Request . . . . . . . . . . . 47
6. Connection Management . . . . . . . . . . . . . . . . . . . . 47 6. Connection Management . . . . . . . . . . . . . . . . . . . . 47
6.1. Connection . . . . . . . . . . . . . . . . . . . . . . . . 47 6.1. Connection . . . . . . . . . . . . . . . . . . . . . . . . 47
6.2. Via . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 6.2. Via . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6.3. Persistent Connections . . . . . . . . . . . . . . . . . . 50 6.3. Persistent Connections . . . . . . . . . . . . . . . . . . 50
6.3.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . 50 6.3.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . 50
6.3.2. Overall Operation . . . . . . . . . . . . . . . . . . 51 6.3.2. Overall Operation . . . . . . . . . . . . . . . . . . 51
6.3.3. Practical Considerations . . . . . . . . . . . . . . . 52 6.3.3. Practical Considerations . . . . . . . . . . . . . . . 53
6.3.4. Retrying Requests . . . . . . . . . . . . . . . . . . 53 6.3.4. Retrying Requests . . . . . . . . . . . . . . . . . . 53
6.4. Message Transmission Requirements . . . . . . . . . . . . 54 6.4. Message Transmission Requirements . . . . . . . . . . . . 54
6.4.1. Persistent Connections and Flow Control . . . . . . . 54 6.4.1. Persistent Connections and Flow Control . . . . . . . 54
6.4.2. Monitoring Connections for Error Status Messages . . . 54 6.4.2. Monitoring Connections for Error Status Messages . . . 54
6.4.3. Use of the 100 (Continue) Status . . . . . . . . . . . 54 6.4.3. Use of the 100 (Continue) Status . . . . . . . . . . . 54
6.4.4. Closing Connections on Error . . . . . . . . . . . . . 56 6.4.4. Closing Connections on Error . . . . . . . . . . . . . 56
6.5. Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 56 6.5. Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 56
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58
7.1. Header Field Registration . . . . . . . . . . . . . . . . 58 7.1. Header Field Registration . . . . . . . . . . . . . . . . 58
7.2. URI Scheme Registration . . . . . . . . . . . . . . . . . 58 7.2. URI Scheme Registration . . . . . . . . . . . . . . . . . 59
7.3. Internet Media Type Registrations . . . . . . . . . . . . 59 7.3. Internet Media Type Registrations . . . . . . . . . . . . 59
7.3.1. Internet Media Type message/http . . . . . . . . . . . 59 7.3.1. Internet Media Type message/http . . . . . . . . . . . 59
7.3.2. Internet Media Type application/http . . . . . . . . . 60 7.3.2. Internet Media Type application/http . . . . . . . . . 60
7.4. Transfer Coding Registry . . . . . . . . . . . . . . . . . 61 7.4. Transfer Coding Registry . . . . . . . . . . . . . . . . . 61
7.5. Transfer Coding Registrations . . . . . . . . . . . . . . 62 7.5. Transfer Coding Registrations . . . . . . . . . . . . . . 62
7.6. Upgrade Token Registry . . . . . . . . . . . . . . . . . . 62 7.6. Upgrade Token Registry . . . . . . . . . . . . . . . . . . 62
7.7. Upgrade Token Registration . . . . . . . . . . . . . . . . 63 7.7. Upgrade Token Registration . . . . . . . . . . . . . . . . 63
8. Security Considerations . . . . . . . . . . . . . . . . . . . 63 8. Security Considerations . . . . . . . . . . . . . . . . . . . 63
8.1. Personal Information . . . . . . . . . . . . . . . . . . . 63 8.1. Personal Information . . . . . . . . . . . . . . . . . . . 63
8.2. Abuse of Server Log Information . . . . . . . . . . . . . 63 8.2. Abuse of Server Log Information . . . . . . . . . . . . . 64
8.3. Attacks Based On File and Path Names . . . . . . . . . . . 64 8.3. Attacks Based On File and Path Names . . . . . . . . . . . 64
8.4. DNS-related Attacks . . . . . . . . . . . . . . . . . . . 64 8.4. DNS-related Attacks . . . . . . . . . . . . . . . . . . . 65
8.5. Intermediaries and Caching . . . . . . . . . . . . . . . . 64 8.5. Intermediaries and Caching . . . . . . . . . . . . . . . . 65
8.6. Protocol Element Size Overflows . . . . . . . . . . . . . 65 8.6. Protocol Element Size Overflows . . . . . . . . . . . . . 65
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 66 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 66
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 67 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 67
10.1. Normative References . . . . . . . . . . . . . . . . . . . 67 10.1. Normative References . . . . . . . . . . . . . . . . . . . 67
10.2. Informative References . . . . . . . . . . . . . . . . . . 68 10.2. Informative References . . . . . . . . . . . . . . . . . . 68
Appendix A. HTTP Version History . . . . . . . . . . . . . . . . 70 Appendix A. HTTP Version History . . . . . . . . . . . . . . . . 71
A.1. Changes from HTTP/1.0 . . . . . . . . . . . . . . . . . . 71 A.1. Changes from HTTP/1.0 . . . . . . . . . . . . . . . . . . 71
A.1.1. Multi-homed Web Servers . . . . . . . . . . . . . . . 71 A.1.1. Multi-homed Web Servers . . . . . . . . . . . . . . . 72
A.1.2. Keep-Alive Connections . . . . . . . . . . . . . . . . 71 A.1.2. Keep-Alive Connections . . . . . . . . . . . . . . . . 72
A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 72 A.1.3. Introduction of Transfer-Encoding . . . . . . . . . . 73
A.3. Changes from RFC 2817 . . . . . . . . . . . . . . . . . . 73 A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 73
Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 73 Appendix B. ABNF list extension: #rule . . . . . . . . . . . . . 74
Appendix C. Change Log (to be removed by RFC Editor before Appendix C. Collected ABNF . . . . . . . . . . . . . . . . . . . 75
publication) . . . . . . . . . . . . . . . . . . . . 76 Appendix D. Change Log (to be removed by RFC Editor before
C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 76 publication) . . . . . . . . . . . . . . . . . . . . 78
C.2. Since draft-ietf-httpbis-p1-messaging-00 . . . . . . . . . 76 D.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 78
C.3. Since draft-ietf-httpbis-p1-messaging-01 . . . . . . . . . 78 D.2. Since draft-ietf-httpbis-p1-messaging-00 . . . . . . . . . 78
C.4. Since draft-ietf-httpbis-p1-messaging-02 . . . . . . . . . 79 D.3. Since draft-ietf-httpbis-p1-messaging-01 . . . . . . . . . 79
C.5. Since draft-ietf-httpbis-p1-messaging-03 . . . . . . . . . 79 D.4. Since draft-ietf-httpbis-p1-messaging-02 . . . . . . . . . 80
C.6. Since draft-ietf-httpbis-p1-messaging-04 . . . . . . . . . 80 D.5. Since draft-ietf-httpbis-p1-messaging-03 . . . . . . . . . 81
C.7. Since draft-ietf-httpbis-p1-messaging-05 . . . . . . . . . 80 D.6. Since draft-ietf-httpbis-p1-messaging-04 . . . . . . . . . 81
C.8. Since draft-ietf-httpbis-p1-messaging-06 . . . . . . . . . 81 D.7. Since draft-ietf-httpbis-p1-messaging-05 . . . . . . . . . 82
C.9. Since draft-ietf-httpbis-p1-messaging-07 . . . . . . . . . 82 D.8. Since draft-ietf-httpbis-p1-messaging-06 . . . . . . . . . 83
C.10. Since draft-ietf-httpbis-p1-messaging-08 . . . . . . . . . 82 D.9. Since draft-ietf-httpbis-p1-messaging-07 . . . . . . . . . 83
C.11. Since draft-ietf-httpbis-p1-messaging-09 . . . . . . . . . 83 D.10. Since draft-ietf-httpbis-p1-messaging-08 . . . . . . . . . 84
C.12. Since draft-ietf-httpbis-p1-messaging-10 . . . . . . . . . 83 D.11. Since draft-ietf-httpbis-p1-messaging-09 . . . . . . . . . 84
C.13. Since draft-ietf-httpbis-p1-messaging-11 . . . . . . . . . 84 D.12. Since draft-ietf-httpbis-p1-messaging-10 . . . . . . . . . 85
C.14. Since draft-ietf-httpbis-p1-messaging-12 . . . . . . . . . 84 D.13. Since draft-ietf-httpbis-p1-messaging-11 . . . . . . . . . 85
C.15. Since draft-ietf-httpbis-p1-messaging-13 . . . . . . . . . 85 D.14. Since draft-ietf-httpbis-p1-messaging-12 . . . . . . . . . 86
C.16. Since draft-ietf-httpbis-p1-messaging-14 . . . . . . . . . 85 D.15. Since draft-ietf-httpbis-p1-messaging-13 . . . . . . . . . 86
C.17. Since draft-ietf-httpbis-p1-messaging-15 . . . . . . . . . 85 D.16. Since draft-ietf-httpbis-p1-messaging-14 . . . . . . . . . 87
C.18. Since draft-ietf-httpbis-p1-messaging-16 . . . . . . . . . 86 D.17. Since draft-ietf-httpbis-p1-messaging-15 . . . . . . . . . 87
C.19. Since draft-ietf-httpbis-p1-messaging-17 . . . . . . . . . 86 D.18. Since draft-ietf-httpbis-p1-messaging-16 . . . . . . . . . 87
C.20. Since draft-ietf-httpbis-p1-messaging-18 . . . . . . . . . 87 D.19. Since draft-ietf-httpbis-p1-messaging-17 . . . . . . . . . 88
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 D.20. Since draft-ietf-httpbis-p1-messaging-18 . . . . . . . . . 88
D.21. Since draft-ietf-httpbis-p1-messaging-19 . . . . . . . . . 89
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
1. Introduction 1. Introduction
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is an application-level
request/response protocol that uses extensible semantics and MIME- request/response protocol that uses extensible semantics and MIME-
like message payloads for flexible interaction with network-based like message payloads for flexible interaction with network-based
hypertext information systems. HTTP relies upon the Uniform Resource hypertext information systems. This document is the first in a
Identifier (URI) standard [RFC3986] to indicate the target resource series of documents that collectively form the HTTP/1.1
(Section 5.1) and relationships between resources. Messages are specification:
passed in a format similar to that used by Internet mail [RFC5322]
and the Multipurpose Internet Mail Extensions (MIME) [RFC2045] (see RFC xxx1: Message Routing and Syntax
Appendix A of [Part3] for the differences between HTTP and MIME
messages). RFC xxx2: Semantics and Payloads
RFC xxx3: Conditional Requests
RFC xxx4: Range Requests
RFC xxx5: Caching
RFC xxx6: Authentication
This HTTP/1.1 specification obsoletes and moves to historic status
RFC 2616, its predecessor RFC 2068, RFC 2145 (on HTTP versioning),
and RFC 2817 (on using CONNECT for TLS upgrades).
HTTP is a generic interface protocol for information systems. It is HTTP is a generic interface protocol for information systems. It is
designed to hide the details of how a service is implemented by designed to hide the details of how a service is implemented by
presenting a uniform interface to clients that is independent of the presenting a uniform interface to clients that is independent of the
types of resources provided. Likewise, servers do not need to be types of resources provided. Likewise, servers do not need to be
aware of each client's purpose: an HTTP request can be considered in aware of each client's purpose: an HTTP request can be considered in
isolation rather than being associated with a specific type of client isolation rather than being associated with a specific type of client
or a predetermined sequence of application steps. The result is a or a predetermined sequence of application steps. The result is a
protocol that can be used effectively in many different contexts and protocol that can be used effectively in many different contexts and
for which implementations can evolve independently over time. for which implementations can evolve independently over time.
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One consequence of HTTP flexibility is that the protocol cannot be One consequence of HTTP flexibility is that the protocol cannot be
defined in terms of what occurs behind the interface. Instead, we defined in terms of what occurs behind the interface. Instead, we
are limited to defining the syntax of communication, the intent of are limited to defining the syntax of communication, the intent of
received communication, and the expected behavior of recipients. If received communication, and the expected behavior of recipients. If
the communication is considered in isolation, then successful actions the communication is considered in isolation, then successful actions
ought to be reflected in corresponding changes to the observable ought to be reflected in corresponding changes to the observable
interface provided by servers. However, since multiple clients might interface provided by servers. However, since multiple clients might
act in parallel and perhaps at cross-purposes, we cannot require that act in parallel and perhaps at cross-purposes, we cannot require that
such changes be observable beyond the scope of a single response. such changes be observable beyond the scope of a single response.
This document is Part 1 of the seven-part specification of HTTP, This document describes the architectural elements that are used or
defining the protocol referred to as "HTTP/1.1", obsoleting [RFC2616] referred to in HTTP, defines the "http" and "https" URI schemes,
and [RFC2145]. Part 1 describes the architectural elements that are describes overall network operation and connection management, and
used or referred to in HTTP, defines the "http" and "https" URI defines HTTP message framing and forwarding requirements. Our goal
schemes, describes overall network operation and connection is to define all of the mechanisms necessary for HTTP message
management, and defines HTTP message framing and forwarding handling that are independent of message semantics, thereby defining
requirements. Our goal is to define all of the mechanisms necessary the complete set of requirements for message parsers and message-
for HTTP message handling that are independent of message semantics, forwarding intermediaries.
thereby defining the complete set of requirements for message parsers
and message-forwarding intermediaries.
1.1. Requirement Notation 1.1. Requirement Notation
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].
1.2. Syntax Notation 1.2. Syntax Notation
This specification uses the Augmented Backus-Naur Form (ABNF) This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234] with the list rule extension defined in notation of [RFC5234] with the list rule extension defined in
Section 3.2.5. Appendix B shows the collected ABNF with the list Appendix B. Appendix C shows the collected ABNF with the list rule
rule expanded. 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), HTAB (horizontal tab), LF (line HEXDIG (hexadecimal 0-9/A-F/a-f), HTAB (horizontal tab), LF (line
feed), OCTET (any 8-bit sequence of data), SP (space), and VCHAR (any feed), OCTET (any 8-bit sequence of data), SP (space), and VCHAR (any
visible [USASCII] character). visible [USASCII] character).
As a convention, ABNF rule names prefixed with "obs-" denote As a convention, ABNF rule names prefixed with "obs-" denote
"obsolete" grammar rules that appear for historical reasons. "obsolete" grammar rules that appear for historical reasons.
skipping to change at page 7, line 47 skipping to change at page 8, line 9
2.1. Client/Server Messaging 2.1. Client/Server Messaging
HTTP is a stateless request/response protocol that operates by HTTP is a stateless request/response protocol that operates by
exchanging messages (Section 3) across a reliable transport or exchanging messages (Section 3) across a reliable transport or
session-layer "connection". An HTTP "client" is a program that session-layer "connection". An HTTP "client" is a program that
establishes a connection to a server for the purpose of sending one establishes a connection to a server for the purpose of sending one
or more HTTP requests. An HTTP "server" is a program that accepts or more HTTP requests. An HTTP "server" is a program that accepts
connections in order to service HTTP requests by sending HTTP connections in order to service HTTP requests by sending HTTP
responses. responses.
Note that the terms client and server refer only to the roles that The terms client and server refer only to the roles that these
these programs perform for a particular connection. The same program programs perform for a particular connection. The same program might
might act as a client on some connections and a server on others. We act as a client on some connections and a server on others. We use
use the term "user agent" to refer to the program that initiates a the term "user agent" to refer to the program that initiates a
request, such as a WWW browser, editor, or spider (web-traversing request, such as a WWW browser, editor, or spider (web-traversing
robot), and the term "origin server" to refer to the program that can robot), and the term "origin server" to refer to the program that can
originate authoritative responses to a request. For general originate authoritative responses to a request. For general
requirements, we use the term "sender" to refer to whichever requirements, we use the term "sender" to refer to whichever
component sent a given message and the term "recipient" to refer to component sent a given message and the term "recipient" to refer to
any component that receives the message. any component that receives the message.
Note: The term 'user agent' covers both those situations where HTTP relies upon the Uniform Resource Identifier (URI) standard
there is a user (human) interacting with the software agent (and [RFC3986] to indicate the target resource (Section 5.1) and
for which user interface or interactive suggestions might be made, relationships between resources. Messages are passed in a format
e.g., warning the user or given the user an option in the case of similar to that used by Internet mail [RFC5322] and the Multipurpose
security or privacy options) and also those where the software Internet Mail Extensions (MIME) [RFC2045] (see Appendix A of [Part2]
agent may act autonomously. for the differences between HTTP and MIME messages).
Most HTTP communication consists of a retrieval request (GET) for a Most HTTP communication consists of a retrieval request (GET) for a
representation of some resource identified by a URI. In the simplest representation of some resource identified by a URI. In the simplest
case, this might be accomplished via a single bidirectional case, this might be accomplished via a single bidirectional
connection (===) between the user agent (UA) and the origin server connection (===) between the user agent (UA) and the origin server
(O). (O).
request > request >
UA ======================================= O UA ======================================= O
< response < response
A client sends an HTTP request to the server in the form of a request A client sends an HTTP request to a server in the form of a request
message, beginning with a request-line that includes a method, URI, message, beginning with a request-line that includes a method, URI,
and protocol version (Section 3.1.1), followed by MIME-like header and protocol version (Section 3.1.1), followed by header fields
fields containing request modifiers, client information, and containing request modifiers, client information, and representation
representation metadata (Section 3.2), an empty line to indicate the
end of the header section, and finally a message body containing the
payload body (if any, Section 3.3).
A server responds to the client's request by sending one or more HTTP
response messages, each beginning with a status line that includes
the protocol version, a success or error code, and textual reason
phrase (Section 3.1.2), possibly followed by MIME-like header fields
containing server information, resource metadata, and representation
metadata (Section 3.2), an empty line to indicate the end of the metadata (Section 3.2), an empty line to indicate the end of the
header section, and finally a message body containing the payload header section, and finally a message body containing the payload
body (if any, Section 3.3). body (if any, Section 3.3).
A server responds to a client's request by sending one or more HTTP
response messages, each beginning with a status line that includes
the protocol version, a success or error code, and textual reason
phrase (Section 3.1.2), possibly followed by header fields containing
server information, resource metadata, and representation metadata
(Section 3.2), an empty line to indicate the end of the header
section, and finally a message body containing the payload body (if
any, Section 3.3).
The following example illustrates a typical message exchange for a The following example illustrates a typical message exchange for a
GET request on the URI "http://www.example.com/hello.txt": GET request on the URI "http://www.example.com/hello.txt":
client request: client request:
GET /hello.txt HTTP/1.1 GET /hello.txt HTTP/1.1
User-Agent: curl/7.16.3 libcurl/7.16.3 OpenSSL/0.9.7l zlib/1.2.3 User-Agent: curl/7.16.3 libcurl/7.16.3 OpenSSL/0.9.7l zlib/1.2.3
Host: www.example.com Host: www.example.com
Accept: */* Accept-Language: en, mi
server response: server response:
HTTP/1.1 200 OK HTTP/1.1 200 OK
Date: Mon, 27 Jul 2009 12:28:53 GMT Date: Mon, 27 Jul 2009 12:28:53 GMT
Server: Apache Server: Apache
Last-Modified: Wed, 22 Jul 2009 19:15:56 GMT Last-Modified: Wed, 22 Jul 2009 19:15:56 GMT
ETag: "34aa387-d-1568eb00" ETag: "34aa387-d-1568eb00"
Accept-Ranges: bytes Accept-Ranges: bytes
Content-Length: 14 Content-Length: 14
Vary: Accept-Encoding Vary: Accept-Encoding
Content-Type: text/plain Content-Type: text/plain
Hello World! Hello World!
2.2. Connections and Transport Independence 2.2. Implementation Diversity
When considering the design of HTTP, it is easy to fall into a trap
of thinking that all user agents are general-purpose browsers and all
origin servers are large public websites. That is not the case in
practice. Common HTTP user agents include household appliances,
stereos, scales, software/firmware updaters, command-line programs,
mobile apps, and communication devices in a multitude of shapes and
sizes. Likewise, common HTTP origin servers include home automation
units, configurable networking components, office machines,
autonomous robots, news feeds, traffic cameras, ad selectors, and
video delivery platforms.
The term "user agent" does not imply that there is a human user
directly interacting with the software agent at the time of a
request. In many cases, a user agent is installed or configured to
run in the background and save its results for later inspection (or
save only a subset of those results that might be interesting or
erroneous). Spiders, for example, are typically given a start URI
and configured to follow certain behavior while crawling the Web as a
hypertext graph.
The implementation diversity of HTTP means that we cannot assume the
user agent can make interactive suggestions to a user or provide
adequate warning for security or privacy options. In the few cases
where this specification requires reporting of errors to the user, it
is acceptable for such reporting to only be visible in an error
console or log file. Likewise, requirements that an automated action
be confirmed by the user before proceeding can me met via advance
configuration choices, run-time options, or simply not proceeding
with the unsafe action.
2.3. Connections and Transport Independence
HTTP messaging is independent of the underlying transport or session- HTTP messaging is independent of the underlying transport or session-
layer connection protocol(s). HTTP only presumes a reliable layer connection protocol(s). HTTP only presumes a reliable
transport with in-order delivery of requests and the corresponding transport with in-order delivery of requests and the corresponding
in-order delivery of responses. The mapping of HTTP request and in-order delivery of responses. The mapping of HTTP request and
response structures onto the data units of the underlying transport response structures onto the data units of the underlying transport
protocol is outside the scope of this specification. protocol is outside the scope of this specification.
The specific connection protocols to be used for an interaction are The specific connection protocols to be used for an interaction are
determined by client configuration and the target URI (Section 5.1). determined by client configuration and the target URI (Section 5.1).
For example, the "http" URI scheme (Section 2.7.1) indicates a For example, the "http" URI scheme (Section 2.8.1) indicates a
default connection of TCP over IP, with a default TCP port of 80, but default connection of TCP over IP, with a default TCP port of 80, but
the client might be configured to use a proxy via some other the client might be configured to use a proxy via some other
connection port or protocol instead of using the defaults. connection port or protocol instead of using the defaults.
A connection might be used for multiple HTTP request/response A connection might be used for multiple HTTP request/response
exchanges, as defined in Section 6.3. exchanges, as defined in Section 6.3.
2.3. Intermediaries 2.4. Intermediaries
HTTP enables the use of intermediaries to satisfy requests through a HTTP enables the use of intermediaries to satisfy requests through a
chain of connections. There are three common forms of HTTP chain of connections. There are three common forms of HTTP
intermediary: proxy, gateway, and tunnel. In some cases, a single intermediary: proxy, gateway, and tunnel. In some cases, a single
intermediary might act as an origin server, proxy, gateway, or intermediary might act as an origin server, proxy, gateway, or
tunnel, switching behavior based on the nature of each request. tunnel, switching behavior based on the nature of each request.
> > > > > > > >
UA =========== A =========== B =========== C =========== O UA =========== A =========== B =========== C =========== O
< < < < < < < <
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that would be significant to the original sender or potentially that would be significant to the original sender or potentially
significant to downstream recipients). For example, a transforming significant to downstream recipients). For example, a transforming
proxy might be acting as a shared annotation server (modifying proxy might be acting as a shared annotation server (modifying
responses to include references to a local annotation database), a responses to include references to a local annotation database), a
malware filter, a format transcoder, or an intranet-to-Internet malware filter, a format transcoder, or an intranet-to-Internet
privacy filter. Such transformations are presumed to be desired by privacy filter. Such transformations are presumed to be desired by
the client (or client organization) that selected the proxy and are the client (or client organization) that selected the proxy and are
beyond the scope of this specification. However, when a proxy is not beyond the scope of this specification. However, when a proxy is not
intended to transform a given message, we use the term "non- intended to transform a given message, we use the term "non-
transforming proxy" to target requirements that preserve HTTP message transforming proxy" to target requirements that preserve HTTP message
semantics. See Section 7.2.4 of [Part2] and Section 3.6 of [Part6] semantics. See Section 4.4.4 of [Part2] and Section 7.6 of [Part6]
for status and warning codes related to transformations. for status and warning codes related to transformations.
A "gateway" (a.k.a., "reverse proxy") is a receiving agent that acts A "gateway" (a.k.a., "reverse proxy") is a receiving agent that acts
as a layer above some other server(s) and translates the received as a layer above some other server(s) and translates the received
requests to the underlying server's protocol. Gateways are often requests to the underlying server's protocol. Gateways are often
used to encapsulate legacy or untrusted information services, to used to encapsulate legacy or untrusted information services, to
improve server performance through "accelerator" caching, and to improve server performance through "accelerator" caching, and to
enable partitioning or load-balancing of HTTP services across enable partitioning or load-balancing of HTTP services across
multiple machines. multiple machines.
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A "tunnel" acts as a blind relay between two connections without A "tunnel" acts as a blind relay between two connections without
changing the messages. Once active, a tunnel is not considered a changing the messages. Once active, a tunnel is not considered a
party to the HTTP communication, though the tunnel might have been party to the HTTP communication, though the tunnel might have been
initiated by an HTTP request. A tunnel ceases to exist when both initiated by an HTTP request. A tunnel ceases to exist when both
ends of the relayed connection are closed. Tunnels are used to ends of the relayed connection are closed. Tunnels are used to
extend a virtual connection through an intermediary, such as when extend a virtual connection through an intermediary, such as when
transport-layer security is used to establish private communication transport-layer security is used to establish private communication
through a shared firewall proxy. through a shared firewall proxy.
In addition, there may exist network intermediaries that are not The above categories for intermediary only consider those acting as
considered part of the HTTP communication but nevertheless act as participants in the HTTP communication. There are also
filters or redirecting agents (usually violating HTTP semantics, intermediaries that can act on lower layers of the network protocol
causing security problems, and otherwise making a mess of things). stack, filtering or redirecting HTTP traffic without the knowledge or
Such a network intermediary, often referred to as an "interception permission of message senders. Network intermediaries often
proxy" [RFC3040], "transparent proxy" [RFC1919], or "captive portal", introduce security flaws or interoperability problems by violating
differs from an HTTP proxy because it has not been selected by the HTTP semantics. For example, an "interception proxy" [RFC3040] (also
client. Instead, the network intermediary redirects outgoing TCP commonly known as a "transparent proxy" [RFC1919] or "captive
port 80 packets (and occasionally other common port traffic) to an portal") differs from an HTTP proxy because it is not selected by the
internal HTTP server. Interception proxies are commonly found on client. Instead, an interception proxy filters or redirects outgoing
public network access points, as a means of enforcing account TCP port 80 packets (and occasionally other common port traffic).
subscription prior to allowing use of non-local Internet services, Interception proxies are commonly found on public network access
and within corporate firewalls to enforce network usage policies. points, as a means of enforcing account subscription prior to
They are indistinguishable from a man-in-the-middle attack. allowing use of non-local Internet services, and within corporate
firewalls to enforce network usage policies. They are
indistinguishable from a man-in-the-middle attack.
HTTP is defined as a stateless protocol, meaning that each request HTTP is defined as a stateless protocol, meaning that each request
message can be understood in isolation. Many implementations depend message can be understood in isolation. Many implementations depend
on HTTP's stateless design in order to reuse proxied connections or on HTTP's stateless design in order to reuse proxied connections or
dynamically load balance requests across multiple servers. Hence, dynamically load balance requests across multiple servers. Hence,
servers MUST NOT assume that two requests on the same connection are servers MUST NOT assume that two requests on the same connection are
from the same user agent unless the connection is secured and from the same user agent unless the connection is secured and
specific to that agent. Some non-standard HTTP extensions (e.g., specific to that agent. Some non-standard HTTP extensions (e.g.,
[RFC4559]) have been known to violate this requirement, resulting in [RFC4559]) have been known to violate this requirement, resulting in
security and interoperability problems. security and interoperability problems.
2.4. Caches 2.5. Caches
A "cache" is a local store of previous response messages and the A "cache" is a local store of previous response messages and the
subsystem that controls its message storage, retrieval, and deletion. subsystem that controls its message storage, retrieval, and deletion.
A cache stores cacheable responses in order to reduce the response A cache stores cacheable responses in order to reduce the response
time and network bandwidth consumption on future, equivalent time and network bandwidth consumption on future, equivalent
requests. Any client or server MAY employ a cache, though a cache requests. Any client or server MAY employ a cache, though a cache
cannot be used by a server while it is acting as a tunnel. cannot be used by a server while it is acting as a tunnel.
The effect of a cache is that the request/response chain is shortened The effect of a cache is that the request/response chain is shortened
if one of the participants along the chain has a cached response if one of the participants along the chain has a cached response
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cache behavior and cacheable responses are defined in Section 2 of cache behavior and cacheable responses are defined in Section 2 of
[Part6]. [Part6].
There are a wide variety of architectures and configurations of There are a wide variety of architectures and configurations of
caches and proxies deployed across the World Wide Web and inside caches and proxies deployed across the World Wide Web and inside
large organizations. These systems include national hierarchies of large organizations. These systems include national hierarchies of
proxy caches to save transoceanic bandwidth, systems that broadcast proxy caches to save transoceanic bandwidth, systems that broadcast
or multicast cache entries, organizations that distribute subsets of or multicast cache entries, organizations that distribute subsets of
cached data via optical media, and so on. cached data via optical media, and so on.
2.5. Conformance and Error Handling 2.6. Conformance and Error Handling
This specification targets conformance criteria according to the role This specification targets conformance criteria according to the role
of a participant in HTTP communication. Hence, HTTP requirements are of a participant in HTTP communication. Hence, HTTP requirements are
placed on senders, recipients, clients, servers, user agents, placed on senders, recipients, clients, servers, user agents,
intermediaries, origin servers, proxies, gateways, or caches, intermediaries, origin servers, proxies, gateways, or caches,
depending on what behavior is being constrained by the requirement. depending on what behavior is being constrained by the requirement.
The verb "generate" is used instead of "send" where a requirement
differentiates between creating a protocol element and merely
forwarding a received element downstream.
An implementation is considered conformant if it complies with all of An implementation is considered conformant if it complies with all of
the requirements associated with the roles it partakes in HTTP. the requirements associated with the roles it partakes in HTTP. Note
that SHOULD-level requirements are relevant here, unless one of the
documented exceptions is applicable.
Senders MUST NOT generate protocol elements that do not match the In addition to the prose requirements placed upon them, senders MUST
grammar defined by the ABNF rules for those protocol elements. NOT generate protocol elements that do not match the grammar defined
by the ABNF rules for those protocol elements that are applicable to
the sender's role. If a received protocol element is processed, the
recipient MUST be able to parse any value that would match the ABNF
rules for that protocol element, excluding only those rules not
applicable to the recipient's role.
Unless otherwise noted, recipients MAY attempt to recover a usable Unless noted otherwise, a recipient MAY attempt to recover a usable
protocol element from an invalid construct. HTTP does not define protocol element from an invalid construct. HTTP does not define
specific error handling mechanisms except when they have a direct specific error handling mechanisms except when they have a direct
impact on security, since different applications of the protocol impact on security, since different applications of the protocol
require different error handling strategies. For example, a Web require different error handling strategies. For example, a Web
browser might wish to transparently recover from a response where the browser might wish to transparently recover from a response where the
Location header field doesn't parse according to the ABNF, whereas a Location header field doesn't parse according to the ABNF, whereas a
systems control client might consider any form of error recovery to systems control client might consider any form of error recovery to
be dangerous. be dangerous.
2.6. Protocol Versioning 2.7. Protocol Versioning
HTTP uses a "<major>.<minor>" numbering scheme to indicate versions HTTP uses a "<major>.<minor>" numbering scheme to indicate versions
of the protocol. This specification defines version "1.1". The of the protocol. This specification defines version "1.1". The
protocol version as a whole indicates the sender's conformance with protocol version as a whole indicates the sender's conformance with
the set of requirements laid out in that version's corresponding the set of requirements laid out in that version's corresponding
specification of HTTP. specification of HTTP.
The version of an HTTP message is indicated by an HTTP-version field The version of an HTTP message is indicated by an HTTP-version field
in the first line of the message. HTTP-version is case-sensitive. in the first line of the message. HTTP-version is case-sensitive.
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header fields ought to be implemented by all HTTP/1.x implementations header fields ought to be implemented by all HTTP/1.x implementations
whether or not they advertise conformance with HTTP/1.1. whether or not they advertise conformance with HTTP/1.1.
New header fields can be defined such that, when they are understood New header fields can be defined such that, when they are understood
by a recipient, they might override or enhance the interpretation of by a recipient, they might override or enhance the interpretation of
previously defined header fields. When an implementation receives an previously defined header fields. When an implementation receives an
unrecognized header field, the recipient MUST ignore that header unrecognized header field, the recipient MUST ignore that header
field for local processing regardless of the message's HTTP version. field for local processing regardless of the message's HTTP version.
An unrecognized header field received by a proxy MUST be forwarded An unrecognized header field received by a proxy MUST be forwarded
downstream unless the header field's field-name is listed in the downstream unless the header field's field-name is listed in the
message's Connection header-field (see Section 6.1). These message's Connection header field (see Section 6.1). These
requirements allow HTTP's functionality to be enhanced without requirements allow HTTP's functionality to be enhanced without
requiring prior update of deployed intermediaries. requiring prior update of deployed intermediaries.
Intermediaries that process HTTP messages (i.e., all intermediaries Intermediaries that process HTTP messages (i.e., all intermediaries
other than those acting as tunnels) MUST send their own HTTP-version other than those acting as tunnels) MUST send their own HTTP-version
in forwarded messages. In other words, they MUST NOT blindly forward in forwarded messages. In other words, they MUST NOT blindly forward
the first line of an HTTP message without ensuring that the protocol the first line of an HTTP message without ensuring that the protocol
version in that message matches a version to which that intermediary version in that message matches a version to which that intermediary
is conformant for both the receiving and sending of messages. is conformant for both the receiving and sending of messages.
Forwarding an HTTP message without rewriting the HTTP-version might Forwarding an HTTP message without rewriting the HTTP-version might
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The intention of HTTP's versioning design is that the major number The intention of HTTP's versioning design is that the major number
will only be incremented if an incompatible message syntax is will only be incremented if an incompatible message syntax is
introduced, and that the minor number will only be incremented when introduced, and that the minor number will only be incremented when
changes made to the protocol have the effect of adding to the message changes made to the protocol have the effect of adding to the message
semantics or implying additional capabilities of the sender. semantics or implying additional capabilities of the sender.
However, the minor version was not incremented for the changes However, the minor version was not incremented for the changes
introduced between [RFC2068] and [RFC2616], and this revision is introduced between [RFC2068] and [RFC2616], and this revision is
specifically avoiding any such changes to the protocol. specifically avoiding any such changes to the protocol.
2.7. Uniform Resource Identifiers 2.8. Uniform Resource Identifiers
Uniform Resource Identifiers (URIs) [RFC3986] are used throughout Uniform Resource Identifiers (URIs) [RFC3986] are used throughout
HTTP as the means for identifying resources. URI references are used HTTP as the means for identifying resources. URI references are used
to target requests, indicate redirects, and define relationships. to target requests, indicate redirects, and define relationships.
HTTP does not limit what a resource might be; it merely defines an HTTP does not limit what a resource might be; it merely defines an
interface that can be used to interact with a resource via HTTP. interface that can be used to interact with a resource via HTTP.
More information on the scope of URIs and resources can be found in More information on the scope of URIs and resources can be found in
[RFC3986]. [RFC3986].
This specification adopts the definitions of "URI-reference", This specification adopts the definitions of "URI-reference",
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partial-URI = relative-part [ "?" query ] partial-URI = relative-part [ "?" query ]
Each protocol element in HTTP that allows a URI reference will Each protocol element in HTTP that allows a URI reference will
indicate in its ABNF production whether the element allows any form indicate in its ABNF production whether the element allows any form
of reference (URI-reference), only a URI in absolute form (absolute- of reference (URI-reference), only a URI in absolute form (absolute-
URI), only the path and optional query components, or some URI), only the path and optional query components, or some
combination of the above. Unless otherwise indicated, URI references combination of the above. Unless otherwise indicated, URI references
are parsed relative to the effective request URI (Section 5.5). are parsed relative to the effective request URI (Section 5.5).
2.7.1. http URI scheme 2.8.1. http URI scheme
The "http" URI scheme is hereby defined for the purpose of minting The "http" URI scheme is hereby defined for the purpose of minting
identifiers according to their association with the hierarchical identifiers according to their association with the hierarchical
namespace governed by a potential HTTP origin server listening for namespace governed by a potential HTTP origin server listening for
TCP connections on a given port. TCP connections on a given port.
http-URI = "http:" "//" authority path-abempty [ "?" query ] http-URI = "http:" "//" authority path-abempty [ "?" query ]
The HTTP origin server is identified by the generic syntax's The HTTP origin server is identified by the generic syntax's
authority component, which includes a host identifier and optional authority component, which includes a host identifier and optional
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authentication information, such as within command invocation authentication information, such as within command invocation
options, configuration files, or bookmark lists, even though such options, configuration files, or bookmark lists, even though such
usage might expose a user identifier or password. Senders MUST NOT usage might expose a user identifier or password. Senders MUST NOT
include a userinfo subcomponent (and its "@" delimiter) when include a userinfo subcomponent (and its "@" delimiter) when
transmitting an "http" URI in a message. Recipients of HTTP messages transmitting an "http" URI in a message. Recipients of HTTP messages
that contain a URI reference SHOULD parse for the existence of that contain a URI reference SHOULD parse for the existence of
userinfo and treat its presence as an error, likely indicating that userinfo and treat its presence as an error, likely indicating that
the deprecated subcomponent is being used to obscure the authority the deprecated subcomponent is being used to obscure the authority
for the sake of phishing attacks. for the sake of phishing attacks.
2.7.2. https URI scheme 2.8.2. https URI scheme
The "https" URI scheme is hereby defined for the purpose of minting The "https" URI scheme is hereby defined for the purpose of minting
identifiers according to their association with the hierarchical identifiers according to their association with the hierarchical
namespace governed by a potential HTTP origin server listening for namespace governed by a potential HTTP origin server listening for
SSL/TLS-secured connections on a given TCP port. SSL/TLS-secured connections on a given TCP port.
All of the requirements listed above for the "http" scheme are also All of the requirements listed above for the "http" scheme are also
requirements for the "https" scheme, except that a default TCP port requirements for the "https" scheme, except that a default TCP port
of 443 is assumed if the port subcomponent is empty or not given, and of 443 is assumed if the port subcomponent is empty or not given, and
the TCP connection MUST be secured for privacy through the use of the TCP connection MUST be secured for privacy through the use of
strong encryption prior to sending the first HTTP request. strong encryption prior to sending the first HTTP request.
https-URI = "https:" "//" authority path-abempty [ "?" query ] https-URI = "https:" "//" authority path-abempty [ "?" query ]
Unlike the "http" scheme, responses to "https" identified requests Unlike the "http" scheme, responses to "https" identified requests
are never "public" and thus MUST NOT be reused for shared caching. are never "public" and thus MUST NOT be reused for shared caching.
They can, however, be reused in a private cache if the message is They can, however, be reused in a private cache if the message is
cacheable by default in HTTP or specifically indicated as such by the cacheable by default in HTTP or specifically indicated as such by the
Cache-Control header field (Section 3.2 of [Part6]). Cache-Control header field (Section 7.2 of [Part6]).
Resources made available via the "https" scheme have no shared Resources made available via the "https" scheme have no shared
identity with the "http" scheme even if their resource identifiers identity with the "http" scheme even if their resource identifiers
indicate the same authority (the same host listening to the same TCP indicate the same authority (the same host listening to the same TCP
port). They are distinct name spaces and are considered to be port). They are distinct name spaces and are considered to be
distinct origin servers. However, an extension to HTTP that is distinct origin servers. However, an extension to HTTP that is
defined to apply to entire host domains, such as the Cookie protocol defined to apply to entire host domains, such as the Cookie protocol
[RFC6265], can allow information set by one service to impact [RFC6265], can allow information set by one service to impact
communication with other services within a matching group of host communication with other services within a matching group of host
domains. domains.
The process for authoritative access to an "https" identified The process for authoritative access to an "https" identified
resource is defined in [RFC2818]. resource is defined in [RFC2818].
2.7.3. http and https URI Normalization and Comparison 2.8.3. http and https URI Normalization and Comparison
Since the "http" and "https" schemes conform to the URI generic Since the "http" and "https" schemes conform to the URI generic
syntax, such URIs are normalized and compared according to the syntax, such URIs are normalized and compared according to the
algorithm defined in [RFC3986], Section 6, using the defaults algorithm defined in [RFC3986], Section 6, using the defaults
described above for each scheme. described above for each scheme.
If the port is equal to the default port for a scheme, the normal If the port is equal to the default port for a scheme, the normal
form is to elide the port subcomponent. Likewise, an empty path form is to elide the port subcomponent. Likewise, an empty path
component is equivalent to an absolute path of "/", so the normal component is equivalent to an absolute path of "/", so the normal
form is to provide a path of "/" instead. The scheme and host are form is to provide a path of "/" instead. The scheme and host are
skipping to change at page 20, line 27 skipping to change at page 21, line 27
some clients or cause others to cease parsing. some clients or cause others to cease parsing.
3.1.1. Request Line 3.1.1. Request Line
A request-line begins with a method token, followed by a single space A request-line begins with a method token, followed by a single space
(SP), the request-target, another single space (SP), the protocol (SP), the request-target, another single space (SP), the protocol
version, and ending with CRLF. version, and ending with CRLF.
request-line = method SP request-target SP HTTP-version CRLF request-line = method SP request-target SP HTTP-version CRLF
A server MUST be able to parse any received message that begins with
a request-line and matches the ABNF rule for HTTP-message.
The method token indicates the request method to be performed on the The method token indicates the request method to be performed on the
target resource. The request method is case-sensitive. target resource. The request method is case-sensitive.
method = token method = token
The methods defined by this specification can be found in Section 2 The methods defined by this specification can be found in Section 2
of [Part2], along with information regarding the HTTP method registry of [Part2], along with information regarding the HTTP method registry
and considerations for defining new methods. and considerations for defining new methods.
The request-target identifies the target resource upon which to apply The request-target identifies the target resource upon which to apply
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directly instead of properly percent-encoding the disallowed directly instead of properly percent-encoding the disallowed
characters. Recipients of an invalid request-line SHOULD respond characters. Recipients of an invalid request-line SHOULD respond
with either a 400 (Bad Request) error or a 301 (Moved Permanently) with either a 400 (Bad Request) error or a 301 (Moved Permanently)
redirect with the request-target properly encoded. Recipients SHOULD redirect with the request-target properly encoded. Recipients SHOULD
NOT attempt to autocorrect and then process the request without a NOT attempt to autocorrect and then process the request without a
redirect, since the invalid request-line might be deliberately redirect, since the invalid request-line might be deliberately
crafted to bypass security filters along the request chain. crafted to bypass security filters along the request chain.
HTTP does not place a pre-defined limit on the length of a request- HTTP does not place a pre-defined limit on the length of a request-
line. A server that receives a method longer than any that it line. A server that receives a method longer than any that it
implements SHOULD respond with either a 404 (Not Allowed), if it is implements SHOULD respond with either a 405 (Method Not Allowed), if
an origin server, or a 501 (Not Implemented) status code. A server it is an origin server, or a 501 (Not Implemented) status code. A
MUST be prepared to receive URIs of unbounded length and respond with server MUST be prepared to receive URIs of unbounded length and
the 414 (URI Too Long) status code if the received request-target respond with the 414 (URI Too Long) status code if the received
would be longer than the server wishes to handle (see Section 7.4.12 request-target would be longer than the server wishes to handle (see
of [Part2]). Section 4.6.12 of [Part2]).
Various ad-hoc limitations on request-line length are found in Various ad-hoc limitations on request-line length are found in
practice. It is RECOMMENDED that all HTTP senders and recipients practice. It is RECOMMENDED that all HTTP senders and recipients
support, at a minimum, request-line lengths of up to 8000 octets. support, at a minimum, request-line lengths of up to 8000 octets.
3.1.2. Status Line 3.1.2. Status Line
The first line of a response message is the status-line, consisting The first line of a response message is the status-line, consisting
of the protocol version, a space (SP), the status code, another of the protocol version, a space (SP), the status code, another
space, a possibly-empty textual phrase describing the status code, space, a possibly-empty textual phrase describing the status code,
and ending with CRLF. and ending with CRLF.
status-line = HTTP-version SP status-code SP reason-phrase CRLF status-line = HTTP-version SP status-code SP reason-phrase CRLF
The status-code element is a 3-digit integer result code of the A client MUST be able to parse any received message that begins with
attempt to understand and satisfy the request. See Section 4 of a status-line and matches the ABNF rule for HTTP-message.
[Part2] for further information, such as the list of status codes
defined by this specification, the IANA registry, and considerations The status-code element is a 3-digit integer code describing the
for new status codes. result of the server's attempt to understand and satisfy the client's
corresponding request. The rest of the response message is to be
interpreted in light of the semantics defined for that status code.
See Section 4 of [Part2] for information about the semantics of
status codes, including the classes of status code (indicated by the
first digit), the status codes defined by this specification,
considerations for the definition of new status codes, and the IANA
registry.
status-code = 3DIGIT status-code = 3DIGIT
The reason-phrase element exists for the sole purpose of providing a The reason-phrase element exists for the sole purpose of providing a
textual description associated with the numeric status code, mostly textual description associated with the numeric status code, mostly
out of deference to earlier Internet application protocols that were out of deference to earlier Internet application protocols that were
more frequently used with interactive text clients. A client SHOULD more frequently used with interactive text clients. A client SHOULD
ignore the reason-phrase content. ignore the reason-phrase content.
reason-phrase = *( HTAB / SP / VCHAR / obs-text ) reason-phrase = *( HTAB / SP / VCHAR / obs-text )
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header-field = field-name ":" OWS field-value BWS header-field = field-name ":" OWS field-value BWS
field-name = token field-name = token
field-value = *( field-content / obs-fold ) field-value = *( field-content / obs-fold )
field-content = *( HTAB / SP / VCHAR / obs-text ) field-content = *( HTAB / SP / VCHAR / obs-text )
obs-fold = CRLF ( SP / HTAB ) obs-fold = CRLF ( SP / HTAB )
; obsolete line folding ; obsolete line folding
; see Section 3.2.2 ; see Section 3.2.2
The field-name token labels the corresponding field-value as having The field-name token labels the corresponding field-value as having
the semantics defined by that header field. For example, the Date the semantics defined by that header field. For example, the Date
header field is defined in Section 10.2 of [Part2] as containing the header field is defined in Section 9.10 of [Part2] as containing the
origination timestamp for the message in which it appears. origination timestamp for the message in which it appears.
HTTP header fields are fully extensible: there is no limit on the HTTP header fields are fully extensible: there is no limit on the
introduction of new field names, each presumably defining new introduction of new field names, each presumably defining new
semantics, or on the number of header fields used in a given message. semantics, or on the number of header fields used in a given message.
Existing fields are defined in each part of this specification and in Existing fields are defined in each part of this specification and in
many other specifications outside the standards process. New header many other specifications outside the standards process. New header
fields can be introduced without changing the protocol version if fields can be introduced without changing the protocol version if
their defined semantics allow them to be safely ignored by recipients their defined semantics allow them to be safely ignored by recipients
that do not recognize them. that do not recognize them.
skipping to change at page 24, line 40 skipping to change at page 25, line 48
header field values use only a subset of the US-ASCII character header field values use only a subset of the US-ASCII character
encoding [USASCII]. Newly defined header fields SHOULD limit their encoding [USASCII]. Newly defined header fields SHOULD limit their
field values to US-ASCII octets. Recipients SHOULD treat other (obs- field values to US-ASCII octets. Recipients SHOULD treat other (obs-
text) octets in field content as opaque data. text) octets in field content as opaque data.
3.2.3. Field Length 3.2.3. Field Length
HTTP does not place a pre-defined limit on the length of header HTTP does not place a pre-defined limit on the length of header
fields, either in isolation or as a set. A server MUST be prepared fields, either in isolation or as a set. A server MUST be prepared
to receive request header fields of unbounded length and respond with to receive request header fields of unbounded length and respond with
a 4xx status code if the received header field(s) would be longer a 4xx (Client Error) status code if the received header field(s)
than the server wishes to handle. would be longer than the server wishes to handle.
A client that receives response headers that are longer than it A client that receives response header fields that are longer than it
wishes to handle can only treat it as a server error. wishes to handle can only treat it as a server error.
Various ad-hoc limitations on header length are found in practice. Various ad-hoc limitations on header field length are found in
It is RECOMMENDED that all HTTP senders and recipients support practice. It is RECOMMENDED that all HTTP senders and recipients
messages whose combined header fields have 4000 or more octets. support messages whose combined header fields have 4000 or more
octets.
3.2.4. Field value components 3.2.4. Field value components
Many HTTP/1.1 header field values consist of words (token or quoted- Many HTTP/1.1 header field values consist of words (token or quoted-
string) separated by whitespace or special characters. These special string) separated by whitespace or special characters. These special
characters MUST be in a quoted string to be used within a parameter characters MUST be in a quoted string to be used within a parameter
value (as defined in Section 4). value (as defined in Section 4).
word = token / quoted-string word = token / quoted-string
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The backslash octet ("\") can be used as a single-octet quoting The backslash octet ("\") can be used as a single-octet quoting
mechanism within comment constructs: mechanism within comment constructs:
quoted-cpair = "\" ( HTAB / SP / VCHAR / obs-text ) quoted-cpair = "\" ( HTAB / SP / VCHAR / obs-text )
Senders SHOULD NOT escape octets in comments that do not require Senders SHOULD NOT escape octets in comments that do not require
escaping (i.e., other than the backslash octet "\" and the escaping (i.e., other than the backslash octet "\" and the
parentheses "(" and ")"). parentheses "(" and ")").
3.2.5. ABNF list extension: #rule
A #rule extension to the ABNF rules of [RFC5234] is used to improve
readability in the definitions of some header field values.
A construct "#" is defined, similar to "*", for defining comma-
delimited lists of elements. The full form is "<n>#<m>element"
indicating at least <n> and at most <m> elements, each separated by a
single comma (",") and optional whitespace (OWS).
Thus,
1#element => element *( OWS "," OWS element )
and:
#element => [ 1#element ]
and for n >= 1 and m > 1:
<n>#<m>element => element <n-1>*<m-1>( OWS "," OWS element )
For compatibility with legacy list rules, recipients SHOULD accept
empty list elements. In other words, consumers would follow the list
productions:
#element => [ ( "," / element ) *( OWS "," [ OWS element ] ) ]
1#element => *( "," OWS ) element *( OWS "," [ OWS element ] )
Note that empty elements do not contribute to the count of elements
present, though.
For example, given these ABNF productions:
example-list = 1#example-list-elmt
example-list-elmt = token ; see Section 3.2.4
Then these are valid values for example-list (not including the
double quotes, which are present for delimitation only):
"foo,bar"
"foo ,bar,"
"foo , ,bar,charlie "
But these values would be invalid, as at least one non-empty element
is required:
""
","
", ,"
Appendix B shows the collected ABNF, with the list rules expanded as
explained above.
3.3. Message Body 3.3. Message Body
The message body (if any) of an HTTP message is used to carry the The message body (if any) of an HTTP message is used to carry the
payload body of that request or response. The message body is payload body of that request or response. The message body is
identical to the payload body unless a transfer coding has been identical to the payload body unless a transfer coding has been
applied, as described in Section 3.3.1. applied, as described in Section 3.3.1.
message-body = *OCTET message-body = *OCTET
The rules for when a message body is allowed in a message differ for The rules for when a message body is allowed in a message differ for
requests and responses. requests and responses.
The presence of a message body in a request is signaled by a a The presence of a message body in a request is signaled by a a
Content-Length or Transfer-Encoding header field. Request message Content-Length or Transfer-Encoding header field. Request message
framing is independent of method semantics, even if the method does framing is independent of method semantics, even if the method does
not define any use for a message body. not define any use for a message body.
The presence of a message body in a response depends on both the The presence of a message body in a response depends on both the
request method to which it is responding and the response status code request method to which it is responding and the response status code
(Paragraph 2). Responses to the HEAD request method never include a (Section 3.1.2). Responses to the HEAD request method never include
message body because the associated response header fields (e.g., a message body because the associated response header fields (e.g.,
Transfer-Encoding, Content-Length, etc.) only indicate what their Transfer-Encoding, Content-Length, etc.) only indicate what their
values would have been if the request method had been GET. values would have been if the request method had been GET. 2xx
Successful (2xx) responses to CONNECT switch to tunnel mode instead (Successful) responses to CONNECT switch to tunnel mode instead of
of having a message body. All 1xx (Informational), 204 (No Content), having a message body. All 1xx (Informational), 204 (No Content),
and 304 (Not Modified) responses MUST NOT include a message body. and 304 (Not Modified) responses MUST NOT include a message body.
All other responses do include a message body, although the body MAY All other responses do include a message body, although the body MAY
be of zero length. be of zero length.
3.3.1. Transfer-Encoding 3.3.1. Transfer-Encoding
When one or more transfer codings are applied to a payload body in When one or more transfer codings are applied to a payload body in
order to form the message body, a Transfer-Encoding header field MUST order to form the message body, a Transfer-Encoding header field MUST
be sent in the message and MUST contain the list of corresponding be sent in the message and MUST contain the list of corresponding
transfer-coding names in the same order that they were applied. transfer-coding names in the same order that they were applied.
skipping to change at page 28, line 42 skipping to change at page 28, line 40
indicates that the payload body has been compressed using the gzip indicates that the payload body has been compressed using the gzip
coding and then chunked using the chunked coding while forming the coding and then chunked using the chunked coding while forming the
message body. message body.
If more than one Transfer-Encoding header field is present in a If more than one Transfer-Encoding header field is present in a
message, the multiple field-values MUST be combined into one field- message, the multiple field-values MUST be combined into one field-
value, according to the algorithm defined in Section 3.2, before value, according to the algorithm defined in Section 3.2, before
determining the message body length. determining the message body length.
Unlike Content-Encoding (Section 2.2 of [Part3]), Transfer-Encoding Unlike Content-Encoding (Section 5.4 of [Part2]), Transfer-Encoding
is a property of the message, not of the payload, and thus MAY be is a property of the message, not of the payload, and thus MAY be
added or removed by any implementation along the request/response added or removed by any implementation along the request/response
chain. Additional information about the encoding parameters MAY be chain. Additional information about the encoding parameters MAY be
provided by other header fields not defined by this specification. provided by other header fields not defined by this specification.
Transfer-Encoding MAY be sent in a response to a HEAD request or in a Transfer-Encoding MAY be sent in a response to a HEAD request or in a
304 response to a GET request, neither of which includes a message 304 (Not Modified) response (Section 4.1 of [Part4]) to a GET
body, to indicate that the origin server would have applied a request, neither of which includes a message body, to indicate that
transfer coding to the message body if the request had been an the origin server would have applied a transfer coding to the message
unconditional GET. This indication is not required, however, because body if the request had been an unconditional GET. This indication
any recipient on the response chain (including the origin server) can is not required, however, because any recipient on the response chain
remove transfer codings when they are not needed. (including the origin server) can remove transfer codings when they
are not needed.
Transfer-Encoding was added in HTTP/1.1. It is generally assumed Transfer-Encoding was added in HTTP/1.1. It is generally assumed
that implementations advertising only HTTP/1.0 support will not that implementations advertising only HTTP/1.0 support will not
understand how to process a transfer-encoded payload. A client MUST understand how to process a transfer-encoded payload. A client MUST
NOT send a request containing Transfer-Encoding unless it knows the NOT send a request containing Transfer-Encoding unless it knows the
server will handle HTTP/1.1 (or later) requests; such knowledge might server will handle HTTP/1.1 (or later) requests; such knowledge might
be in the form of specific user configuration or by remembering the be in the form of specific user configuration or by remembering the
version of a prior received response. A server MUST NOT send a version of a prior received response. A server MUST NOT send a
response containing Transfer-Encoding unless the corresponding response containing Transfer-Encoding unless the corresponding
request indicates HTTP/1.1 (or later). request indicates HTTP/1.1 (or later).
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A server that receives a request message with a transfer-coding it A server that receives a request message with a transfer-coding it
does not understand SHOULD respond with 501 (Not Implemented) and does not understand SHOULD respond with 501 (Not Implemented) and
then close the connection. then close the connection.
3.3.2. Content-Length 3.3.2. Content-Length
When a message does not have a Transfer-Encoding header field and the When a message does not have a Transfer-Encoding header field and the
payload body length can be determined prior to being transferred, a payload body length can be determined prior to being transferred, a
Content-Length header field SHOULD be sent to indicate the length of Content-Length header field SHOULD be sent to indicate the length of
the payload body that is either present as the message body, for the payload body that is either present as the message body, for
requests and non-HEAD responses other than 304, or would have been requests and non-HEAD responses other than 304 (Not Modified), or
present had the request been an unconditional GET. The length is would have been present had the request been an unconditional GET.
expressed as a decimal number of octets. The length is expressed as a decimal number of octets.
Content-Length = 1*DIGIT Content-Length = 1*DIGIT
An example is An example is
Content-Length: 3495 Content-Length: 3495
In the case of a response to a HEAD request, Content-Length indicates In the case of a response to a HEAD request, Content-Length indicates
the size of the payload body (without any potential transfer-coding) the size of the payload body (without any potential transfer-coding)
that would have been sent had the request been a GET. In the case of that would have been sent had the request been a GET. In the case of
a 304 (Not Modified) response to a GET request, Content-Length a 304 (Not Modified) response (Section 4.1 of [Part4]) to a GET
indicates the size of the payload body (without any potential request, Content-Length indicates the size of the payload body
transfer-coding) that would have been sent in a 200 (OK) response. (without any potential transfer-coding) that would have been sent in
a 200 (OK) response.
HTTP's use of Content-Length is significantly different from how it
is used in MIME, where it is an optional field used only within the
"message/external-body" media-type.
Any Content-Length field value greater than or equal to zero is Any Content-Length field value greater than or equal to zero is
valid. Since there is no predefined limit to the length of an HTTP valid. Since there is no predefined limit to the length of an HTTP
payload, recipients SHOULD anticipate potentially large decimal payload, recipients SHOULD anticipate potentially large decimal
numerals and prevent parsing errors due to integer conversion numerals and prevent parsing errors due to integer conversion
overflows (Section 8.6). overflows (Section 8.6).
If a message is received that has multiple Content-Length header If a message is received that has multiple Content-Length header
fields (Section 3.3.2) with field-values consisting of the same fields with field-values consisting of the same decimal value, or a
decimal value, or a single Content-Length header field with a field single Content-Length header field with a field value containing a
value containing a list of identical decimal values (e.g., "Content- list of identical decimal values (e.g., "Content-Length: 42, 42"),
Length: 42, 42"), indicating that duplicate Content-Length header indicating that duplicate Content-Length header fields have been
fields have been generated or combined by an upstream message generated or combined by an upstream message processor, then the
processor, then the recipient MUST either reject the message as recipient MUST either reject the message as invalid or replace the
invalid or replace the duplicated field-values with a single valid duplicated field-values with a single valid Content-Length field
Content-Length field containing that decimal value prior to containing that decimal value prior to determining the message body
determining the message body length. length.
Note: HTTP's use of Content-Length for message framing differs
significantly from the same field's use in MIME, where it is an
optional field used only within the "message/external-body" media-
type.
3.3.3. Message Body Length 3.3.3. Message Body Length
The length of a message body is determined by one of the following The length of a message body is determined by one of the following
(in order of precedence): (in order of precedence):
1. Any response to a HEAD request and any response with a status 1. Any response to a HEAD request and any response with a 1xx
code of 100-199, 204, or 304 is always terminated by the first (Informational), 204 (No Content), or 304 (Not Modified) status
empty line after the header fields, regardless of the header code is always terminated by the first empty line after the
fields present in the message, and thus cannot contain a message header fields, regardless of the header fields present in the
body. message, and thus cannot contain a message body.
2. Any successful (2xx) response to a CONNECT request implies that 2. Any 2xx (Successful) response to a CONNECT request implies that
the connection will become a tunnel immediately after the empty the connection will become a tunnel immediately after the empty
line that concludes the header fields. A client MUST ignore any line that concludes the header fields. A client MUST ignore any
Content-Length or Transfer-Encoding header fields received in Content-Length or Transfer-Encoding header fields received in
such a message. such a message.
3. If a Transfer-Encoding header field is present and the "chunked" 3. If a Transfer-Encoding header field is present and the "chunked"
transfer-coding (Section 4.1) is the final encoding, the message transfer-coding (Section 4.1) is the final encoding, the message
body length is determined by reading and decoding the chunked body length is determined by reading and decoding the chunked
data until the transfer-coding indicates the data is complete. data until the transfer-coding indicates the data is complete.
If a Transfer-Encoding header field is present in a response and If a Transfer-Encoding header field is present in a response and
the "chunked" transfer-coding is not the final encoding, the the "chunked" transfer-coding is not the final encoding, the
message body length is determined by reading the connection until message body length is determined by reading the connection until
it is closed by the server. If a Transfer-Encoding header field it is closed by the server. If a Transfer-Encoding header field
is present in a request and the "chunked" transfer-coding is not is present in a request and the "chunked" transfer-coding is not
the final encoding, the message body length cannot be determined the final encoding, the message body length cannot be determined
reliably; the server MUST respond with the 400 (Bad Request) reliably; the server MUST respond with the 400 (Bad Request)
status code and then close the connection. status code and then close the connection.
If a message is received with both a Transfer-Encoding header If a message is received with both a Transfer-Encoding and a
field and a Content-Length header field, the Transfer-Encoding Content-Length header field, the Transfer-Encoding overrides the
overrides the Content-Length. Such a message might indicate an Content-Length. Such a message might indicate an attempt to
attempt to perform request or response smuggling (bypass of perform request or response smuggling (bypass of security-related
security-related checks on message routing or content) and thus checks on message routing or content) and thus ought to be
ought to be handled as an error. The provided Content-Length handled as an error. The provided Content-Length MUST be
MUST be removed, prior to forwarding the message downstream, or removed, prior to forwarding the message downstream, or replaced
replaced with the real message body length after the transfer- with the real message body length after the transfer-coding is
coding is decoded. decoded.
4. If a message is received without Transfer-Encoding and with 4. If a message is received without Transfer-Encoding and with
either multiple Content-Length header fields having differing either multiple Content-Length header fields having differing
field-values or a single Content-Length header field having an field-values or a single Content-Length header field having an
invalid value, then the message framing is invalid and MUST be invalid value, then the message framing is invalid and MUST be
treated as an error to prevent request or response smuggling. If treated as an error to prevent request or response smuggling. If
this is a request message, the server MUST respond with a 400 this is a request message, the server MUST respond with a 400
(Bad Request) status code and then close the connection. If this (Bad Request) status code and then close the connection. If this
is a response message received by a proxy, the proxy MUST discard is a response message received by a proxy, the proxy MUST discard
the received response, send a 502 (Bad Gateway) status code as the received response, send a 502 (Bad Gateway) status code as
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A client that sends a request containing a message body MUST include A client that sends a request containing a message body MUST include
a valid Content-Length header field if it does not know the server a valid Content-Length header field if it does not know the server
will handle HTTP/1.1 (or later) requests; such knowledge can be in will handle HTTP/1.1 (or later) requests; such knowledge can be in
the form of specific user configuration or by remembering the version the form of specific user configuration or by remembering the version
of a prior received response. of a prior received response.
3.4. Handling Incomplete Messages 3.4. Handling Incomplete Messages
Request messages that are prematurely terminated, possibly due to a Request messages that are prematurely terminated, possibly due to a
cancelled connection or a server-imposed time-out exception, MUST canceled connection or a server-imposed time-out exception, MUST
result in closure of the connection; sending an HTTP/1.1 error result in closure of the connection; sending an HTTP/1.1 error
response prior to closing the connection is OPTIONAL. response prior to closing the connection is OPTIONAL.
Response messages that are prematurely terminated, usually by closure Response messages that are prematurely terminated, usually by closure
of the connection prior to receiving the expected number of octets or of the connection prior to receiving the expected number of octets or
by failure to decode a transfer-encoded message body, MUST be by failure to decode a transfer-encoded message body, MUST be
recorded as incomplete. A response that terminates in the middle of recorded as incomplete. A response that terminates in the middle of
the header block (before the empty line is received) cannot be the header block (before the empty line is received) cannot be
assumed to convey the full semantics of the response and MUST be assumed to convey the full semantics of the response and MUST be
treated as an error. treated as an error.
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if the zero-sized chunk that terminates the encoding has not been if the zero-sized chunk that terminates the encoding has not been
received. A message that uses a valid Content-Length is incomplete received. A message that uses a valid Content-Length is incomplete
if the size of the message body received (in octets) is less than the if the size of the message body received (in octets) is less than the
value given by Content-Length. A response that has neither chunked value given by Content-Length. A response that has neither chunked
transfer encoding nor Content-Length is terminated by closure of the transfer encoding nor Content-Length is terminated by closure of the
connection, and thus is considered complete regardless of the number connection, and thus is considered complete regardless of the number
of message body octets received, provided that the header block was of message body octets received, provided that the header block was
received intact. received intact.
A user agent MUST NOT render an incomplete response message body as A user agent MUST NOT render an incomplete response message body as
if it were complete (i.e., some indication must be given to the user if it were complete (i.e., some indication needs to be given to the
that an error occurred). Cache requirements for incomplete responses user that an error occurred). Cache requirements for incomplete
are defined in Section 2.1 of [Part6]. responses are defined in Section 3 of [Part6].
A server MUST read the entire request message body or close the A server MUST read the entire request message body or close the
connection after sending its response, since otherwise the remaining connection after sending its response, since otherwise the remaining
data on a persistent connection would be misinterpreted as the next data on a persistent connection would be misinterpreted as the next
request. Likewise, a client MUST read the entire response message request. Likewise, a client MUST read the entire response message
body if it intends to reuse the same connection for a subsequent body if it intends to reuse the same connection for a subsequent
request. Pipelining multiple requests on a connection is described request. Pipelining multiple requests on a connection is described
in Section 6.3.2.2. in Section 6.3.2.2.
3.5. Message Parsing Robustness 3.5. Message Parsing Robustness
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trailer for any header fields unless at least one of the following is trailer for any header fields unless at least one of the following is
true: true:
1. the request included a TE header field that indicates "trailers" 1. the request included a TE header field that indicates "trailers"
is acceptable in the transfer-coding of the response, as is acceptable in the transfer-coding of the response, as
described in Section 4.3; or, described in Section 4.3; or,
2. the trailer fields consist entirely of optional metadata, and the 2. the trailer fields consist entirely of optional metadata, and the
recipient could use the message (in a manner acceptable to the recipient could use the message (in a manner acceptable to the
server where the field originated) without receiving it. In server where the field originated) without receiving it. In
other words, the server that generated the header (often but not other words, the server that generated the header field (often
always the origin server) is willing to accept the possibility but not always the origin server) is willing to accept the
that the trailer fields might be silently discarded along the possibility that the trailer fields might be silently discarded
path to the client. along the path to the client.
This requirement prevents an interoperability failure when the This requirement prevents an interoperability failure when the
message is being received by an HTTP/1.1 (or later) proxy and message is being received by an HTTP/1.1 (or later) proxy and
forwarded to an HTTP/1.0 recipient. It avoids a situation where forwarded to an HTTP/1.0 recipient. It avoids a situation where
conformance with the protocol would have necessitated a possibly conformance with the protocol would have necessitated a possibly
infinite buffer on the proxy. infinite buffer on the proxy.
A process for decoding the "chunked" transfer-coding can be A process for decoding the "chunked" transfer-coding can be
represented in pseudo-code as: represented in pseudo-code as:
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transfer-coding with the highest non-zero qvalue is preferred. transfer-coding with the highest non-zero qvalue is preferred.
The "chunked" transfer-coding always has a qvalue of 1. The "chunked" transfer-coding always has a qvalue of 1.
If the TE field-value is empty or if no TE field is present, the only If the TE field-value is empty or if no TE field is present, the only
acceptable transfer-coding is "chunked". A message with no transfer- acceptable transfer-coding is "chunked". A message with no transfer-
coding is always acceptable. coding is always acceptable.
4.3.1. Quality Values 4.3.1. Quality Values
Both transfer codings (TE request header field, Section 4.3) and Both transfer codings (TE request header field, Section 4.3) and
content negotiation (Section 5 of [Part3]) use short "floating point" content negotiation (Section 8 of [Part2]) use short "floating point"
numbers to indicate the relative importance ("weight") of various numbers to indicate the relative importance ("weight") of various
negotiable parameters. A weight is normalized to a real number in negotiable parameters. A weight is normalized to a real number in
the range 0 through 1, where 0 is the minimum and 1 the maximum the range 0 through 1, where 0 is the minimum and 1 the maximum
value. If a parameter has a quality value of 0, then content with value. If a parameter has a quality value of 0, then content with
this parameter is "not acceptable" for the client. HTTP/1.1 this parameter is "not acceptable" for the client. HTTP/1.1
applications MUST NOT generate more than three digits after the applications MUST NOT generate more than three digits after the
decimal point. User configuration of these values SHOULD also be decimal point. User configuration of these values SHOULD also be
limited in this fashion. limited in this fashion.
qvalue = ( "0" [ "." 0*3DIGIT ] ) qvalue = ( "0" [ "." 0*3DIGIT ] )
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HTTP is used in a wide variety of applications, ranging from general- HTTP is used in a wide variety of applications, ranging from general-
purpose computers to home appliances. In some cases, communication purpose computers to home appliances. In some cases, communication
options are hard-coded in a client's configuration. However, most options are hard-coded in a client's configuration. However, most
HTTP clients rely on the same resource identification mechanism and HTTP clients rely on the same resource identification mechanism and
configuration techniques as general-purpose Web browsers. configuration techniques as general-purpose Web browsers.
HTTP communication is initiated by a user agent for some purpose. HTTP communication is initiated by a user agent for some purpose.
The purpose is a combination of request semantics, which are defined The purpose is a combination of request semantics, which are defined
in [Part2], and a target resource upon which to apply those in [Part2], and a target resource upon which to apply those
semantics. A URI reference (Section 2.7) is typically used as an semantics. A URI reference (Section 2.8) is typically used as an
identifier for the "target resource", which a user agent would identifier for the "target resource", which a user agent would
resolve to its absolute form in order to obtain the "target URI". resolve to its absolute form in order to obtain the "target URI".
The target URI excludes the reference's fragment identifier The target URI excludes the reference's fragment identifier
component, if any, since fragment identifiers are reserved for component, if any, since fragment identifiers are reserved for
client-side processing ([RFC3986], Section 3.5). client-side processing ([RFC3986], Section 3.5).
HTTP intermediaries obtain the request semantics and target URI from HTTP intermediaries obtain the request semantics and target URI from
the request-line of an incoming request message. the request-line of an incoming request message.
5.2. Connecting Inbound 5.2. Connecting Inbound
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authority matching, or both, and the proxy itself is usually authority matching, or both, and the proxy itself is usually
identified by an "http" or "https" URI. If a proxy is applicable, identified by an "http" or "https" URI. If a proxy is applicable,
the client connects inbound by establishing (or reusing) a connection the client connects inbound by establishing (or reusing) a connection
to that proxy. to that proxy.
If no proxy is applicable, a typical client will invoke a handler If no proxy is applicable, a typical client will invoke a handler
routine, usually specific to the target URI's scheme, to connect routine, usually specific to the target URI's scheme, to connect
directly to an authority for the target resource. How that is directly to an authority for the target resource. How that is
accomplished is dependent on the target URI scheme and defined by its accomplished is dependent on the target URI scheme and defined by its
associated specification, similar to how this specification defines associated specification, similar to how this specification defines
origin server access for resolution of the "http" (Section 2.7.1) and origin server access for resolution of the "http" (Section 2.8.1) and
"https" (Section 2.7.2) schemes. "https" (Section 2.8.2) schemes.
5.3. Request Target 5.3. Request Target
Once an inbound connection is obtained (Section 6), the client sends Once an inbound connection is obtained (Section 6), the client sends
an HTTP request message (Section 3) with a request-target derived an HTTP request message (Section 3) with a request-target derived
from the target URI. There are four distinct formats for the from the target URI. There are four distinct formats for the
request-target, depending on both the method being requested and request-target, depending on both the method being requested and
whether the request is to a proxy. whether the request is to a proxy.
request-target = origin-form request-target = origin-form
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An example absolute-form of request-line would be: An example absolute-form of request-line would be:
GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1 GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
To allow for transition to the absolute-form for all requests in some To allow for transition to the absolute-form for all requests in some
future version of HTTP, HTTP/1.1 servers MUST accept the absolute- future version of HTTP, HTTP/1.1 servers MUST accept the absolute-
form in requests, even though HTTP/1.1 clients will only send them in form in requests, even though HTTP/1.1 clients will only send them in
requests to proxies. requests to proxies.
The authority-form of request-target is only used for CONNECT The authority-form of request-target is only used for CONNECT
requests (Section 6.9 of [Part2]). When making a CONNECT request to requests (Section 2.3.8 of [Part2]). When making a CONNECT request
establish a tunnel through one or more proxies, a client MUST send to establish a tunnel through one or more proxies, a client MUST send
only the target URI's authority component (excluding any userinfo) as only the target URI's authority component (excluding any userinfo) as
the request-target. For example, the request-target. For example,
CONNECT www.example.com:80 HTTP/1.1 CONNECT www.example.com:80 HTTP/1.1
The asterisk-form of request-target is only used for a server-wide The asterisk-form of request-target is only used for a server-wide
OPTIONS request (Section 6.2 of [Part2]). When a client wishes to OPTIONS request (Section 2.3.1 of [Part2]). When a client wishes to
request OPTIONS for the server as a whole, as opposed to a specific request OPTIONS for the server as a whole, as opposed to a specific
named resource of that server, the client MUST send only "*" (%x2A) named resource of that server, the client MUST send only "*" (%x2A)
as the request-target. For example, as the request-target. For example,
OPTIONS * HTTP/1.1 OPTIONS * HTTP/1.1
If a proxy receives an OPTIONS request with an absolute-form of If a proxy receives an OPTIONS request with an absolute-form of
request-target in which the URI has an empty path and no query request-target in which the URI has an empty path and no query
component, then the last proxy on the request chain MUST send a component, then the last proxy on the request chain MUST send a
request-target of "*" when it forwards the request to the indicated request-target of "*" when it forwards the request to the indicated
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5.4. Host 5.4. Host
The "Host" header field in a request provides the host and port The "Host" header field in a request provides the host and port
information from the target URI, enabling the origin server to information from the target URI, enabling the origin server to
distinguish among resources while servicing requests for multiple distinguish among resources while servicing requests for multiple
host names on a single IP address. Since the Host field-value is host names on a single IP address. Since the Host field-value is
critical information for handling a request, it SHOULD be sent as the critical information for handling a request, it SHOULD be sent as the
first header field following the request-line. first header field following the request-line.
Host = uri-host [ ":" port ] ; Section 2.7.1 Host = uri-host [ ":" port ] ; Section 2.8.1
A client MUST send a Host header field in all HTTP/1.1 request A client MUST send a Host header field in all HTTP/1.1 request
messages. If the target URI includes an authority component, then messages. If the target URI includes an authority component, then
the Host field-value MUST be identical to that authority component the Host field-value MUST be identical to that authority component
after excluding any userinfo (Section 2.7.1). If the authority after excluding any userinfo (Section 2.8.1). If the authority
component is missing or undefined for the target URI, then the Host component is missing or undefined for the target URI, then the Host
header field MUST be sent with an empty field-value. header field MUST be sent with an empty field-value.
For example, a GET request to the origin server for For example, a GET request to the origin server for
<http://www.example.org/pub/WWW/> would begin with: <http://www.example.org/pub/WWW/> would begin with:
GET /pub/WWW/ HTTP/1.1 GET /pub/WWW/ HTTP/1.1
Host: www.example.org Host: www.example.org
The Host header field MUST be sent in an HTTP/1.1 request even if the The Host header field MUST be sent in an HTTP/1.1 request even if the
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A server MUST respond with a 400 (Bad Request) status code to any A server MUST respond with a 400 (Bad Request) status code to any
HTTP/1.1 request message that lacks a Host header field and to any HTTP/1.1 request message that lacks a Host header field and to any
request message that contains more than one Host header field or a request message that contains more than one Host header field or a
Host header field with an invalid field-value. Host header field with an invalid field-value.
5.5. Effective Request URI 5.5. Effective Request URI
A server that receives an HTTP request message MUST reconstruct the A server that receives an HTTP request message MUST reconstruct the
user agent's original target URI, based on the pieces of information user agent's original target URI, based on the pieces of information
learned from the request-target, Host, and connection context, in learned from the request-target, Host header field, and connection
order to identify the intended target resource and properly service context, in order to identify the intended target resource and
the request. The URI derived from this reconstruction process is properly service the request. The URI derived from this
referred to as the "effective request URI". reconstruction process is referred to as the "effective request URI".
For a user agent, the effective request URI is the target URI. For a user agent, the effective request URI is the target URI.
If the request-target is in absolute-form, then the effective request If the request-target is in absolute-form, then the effective request
URI is the same as the request-target. Otherwise, the effective URI is the same as the request-target. Otherwise, the effective
request URI is constructed as follows. request URI is constructed as follows.
If the request is received over an SSL/TLS-secured TCP connection, If the request is received over an SSL/TLS-secured TCP connection,
then the effective request URI's scheme is "https"; otherwise, the then the effective request URI's scheme is "https"; otherwise, the
scheme is "http". scheme is "http".
If the request-target is in authority-form, then the effective If the request-target is in authority-form, then the effective
request URI's authority component is the same as the request-target. request URI's authority component is the same as the request-target.
Otherwise, if a Host header field is supplied with a non-empty field- Otherwise, if a Host header field is supplied with a non-empty field-
value, then the authority component is the same as the Host field- value, then the authority component is the same as the Host field-
value. Otherwise, the authority component is the concatenation of value. Otherwise, the authority component is the concatenation of
the default hostname configured for the server, a colon (":"), and the default host name configured for the server, a colon (":"), and
the connection's incoming TCP port number in decimal form. the connection's incoming TCP port number in decimal form.
If the request-target is in authority-form or asterisk-form, then the If the request-target is in authority-form or asterisk-form, then the
effective request URI's combined path and query component is empty. effective request URI's combined path and query component is empty.
Otherwise, the combined path and query component is the same as the Otherwise, the combined path and query component is the same as the
request-target. request-target.
The components of the effective request URI, once determined as The components of the effective request URI, once determined as
above, can be combined into absolute-URI form by concatenating the above, can be combined into absolute-URI form by concatenating the
scheme, "://", authority, and combined path and query component. scheme, "://", authority, and combined path and query component.
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host MAY ignore the Host field-value and instead replace it with a host MAY ignore the Host field-value and instead replace it with a
configured server name when constructing the effective request URI. configured server name when constructing the effective request URI.
Recipients of an HTTP/1.0 request that lacks a Host header field MAY Recipients of an HTTP/1.0 request that lacks a Host header field MAY
attempt to use heuristics (e.g., examination of the URI path for attempt to use heuristics (e.g., examination of the URI path for
something unique to a particular host) in order to guess the something unique to a particular host) in order to guess the
effective request URI's authority component. effective request URI's authority component.
5.6. Intermediary Forwarding 5.6. Intermediary Forwarding
As described in Section 2.3, intermediaries can serve a variety of As described in Section 2.4, intermediaries can serve a variety of
roles in the processing of HTTP requests and responses. Some roles in the processing of HTTP requests and responses. Some
intermediaries are used to improve performance or availability. intermediaries are used to improve performance or availability.
Others are used for access control or to filter content. Since an Others are used for access control or to filter content. Since an
HTTP stream has characteristics similar to a pipe-and-filter HTTP stream has characteristics similar to a pipe-and-filter
architecture, there are no inherent limits to the extent an architecture, there are no inherent limits to the extent an
intermediary can enhance (or interfere) with either direction of the intermediary can enhance (or interfere) with either direction of the
stream. stream.
In order to avoid request loops, a proxy that forwards requests to In order to avoid request loops, a proxy that forwards requests to
other proxies MUST be able to recognize and exclude all of its own other proxies MUST be able to recognize and exclude all of its own
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transmitted in any response formed from a cache entry. transmitted in any response formed from a cache entry.
o Hop-by-hop header fields, which are meaningful only for a single o Hop-by-hop header fields, which are meaningful only for a single
transport-level connection, and are not stored by caches or transport-level connection, and are not stored by caches or
forwarded by proxies. forwarded by proxies.
The following HTTP/1.1 header fields are hop-by-hop header fields: The following HTTP/1.1 header fields are hop-by-hop header fields:
o Connection o Connection
o Keep-Alive o Keep-Alive (Section 19.7.1.1 of [RFC2068])
o Proxy-Authenticate o Proxy-Authenticate (Section 4.2 of [Part7])
o Proxy-Authorization o Proxy-Authorization (Section 4.3 of [Part7])
o TE o TE
o Trailer o Trailer
o Transfer-Encoding o Transfer-Encoding
o Upgrade o Upgrade
All other header fields defined by HTTP/1.1 are end-to-end header All other header fields defined by HTTP/1.1 are end-to-end header
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Some features of HTTP/1.1, such as Digest Authentication, depend on Some features of HTTP/1.1, such as Digest Authentication, depend on
the value of certain end-to-end header fields. A non-transforming the value of certain end-to-end header fields. A non-transforming
proxy SHOULD NOT modify an end-to-end header field unless the proxy SHOULD NOT modify an end-to-end header field unless the
definition of that header field requires or specifically allows that. definition of that header field requires or specifically allows that.
A non-transforming proxy MUST NOT modify any of the following fields A non-transforming proxy MUST NOT modify any of the following fields
in a request or response, and it MUST NOT add any of these fields if in a request or response, and it MUST NOT add any of these fields if
not already present: not already present:
o Allow o Allow (Section 9.5 of [Part2])
o Content-Location o Content-Location (Section 9.8 of [Part2])
o Content-MD5 o Content-MD5 (Section 14.15 of [RFC2616])
o ETag o ETag (Section 2.3 of [Part4])
o Last-Modified o Last-Modified (Section 2.2 of [Part4])
o Server o Server (Section 9.17 of [Part2])
A non-transforming proxy MUST NOT modify any of the following fields A non-transforming proxy MUST NOT modify any of the following fields
in a response: in a response:
o Expires o Expires (Section 7.3 of [Part6])
but it MAY add any of these fields if not already present. If an but it MAY add any of these fields if not already present. If an
Expires header field is added, it MUST be given a field-value Expires header field is added, it MUST be given a field value
identical to that of the Date header field in that response. identical to that of the Date header field in that response.
A proxy MUST NOT modify or add any of the following fields in a A proxy MUST NOT modify or add any of the following fields in a
message that contains the no-transform cache-control directive, or in message that contains the no-transform cache-control directive, or in
any request: any request:
o Content-Encoding o Content-Encoding (Section 9.6 of [Part2])
o Content-Range o Content-Range (Section 5.2 of [Part5])
o Content-Type o Content-Type (Section 9.9 of [Part2])
A transforming proxy MAY modify or add these fields to a message that A transforming proxy MAY modify or add these fields to a message that
does not include no-transform, but if it does so, it MUST add a does not include no-transform, but if it does so, it MUST add a
Warning 214 (Transformation applied) if one does not already appear Warning 214 (Transformation applied) if one does not already appear
in the message (see Section 3.6 of [Part6]). in the message (see Section 7.6 of [Part6]).
Warning: Unnecessary modification of end-to-end header fields Warning: Unnecessary modification of end-to-end header fields
might cause authentication failures if stronger authentication might cause authentication failures if stronger authentication
mechanisms are introduced in later versions of HTTP. Such mechanisms are introduced in later versions of HTTP. Such
authentication mechanisms MAY rely on the values of header fields authentication mechanisms MAY rely on the values of header fields
not listed here. not listed here.
A non-transforming proxy MUST preserve the message payload ([Part3]), A non-transforming proxy MUST preserve the message payload ([Part2]),
though it MAY change the message body through application or removal though it MAY change the message body through application or removal
of a transfer-coding (Section 4). of a transfer-coding (Section 4).
5.7. Associating a Response to a Request 5.7. Associating a Response to a Request
HTTP does not include a request identifier for associating a given HTTP does not include a request identifier for associating a given
request message with its corresponding one or more response messages. request message with its corresponding one or more response messages.
Hence, it relies on the order of response arrival to correspond Hence, it relies on the order of response arrival to correspond
exactly to the order in which requests are made on the same exactly to the order in which requests are made on the same
connection. More than one response message per request only occurs connection. More than one response message per request only occurs
when one or more informational responses (1xx, see Section 7.1 of when one or more informational responses (1xx, see Section 4.3 of
[Part2]) precede a final response to the same request. [Part2]) precede a final response to the same request.
A client that uses persistent connections and sends more than one A client that uses persistent connections and sends more than one
request per connection MUST maintain a list of outstanding requests request per connection MUST maintain a list of outstanding requests
in the order sent on that connection and MUST associate each received in the order sent on that connection and MUST associate each received
response message to the highest ordered request that has not yet response message to the highest ordered request that has not yet
received a final (non-1xx) response. received a final (non-1xx) response.
6. Connection Management 6. Connection Management
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be forwarded downstream by a proxy or gateway. This mechanism also be forwarded downstream by a proxy or gateway. This mechanism also
allows the sender to indicate which HTTP header fields used in the allows the sender to indicate which HTTP header fields used in the
message are only intended for the immediate recipient ("hop-by-hop"), message are only intended for the immediate recipient ("hop-by-hop"),
as opposed to all recipients on the chain ("end-to-end"), enabling as opposed to all recipients on the chain ("end-to-end"), enabling
the message to be self-descriptive and allowing future connection- the message to be self-descriptive and allowing future connection-
specific extensions to be deployed in HTTP without fear that they specific extensions to be deployed in HTTP without fear that they
will be blindly forwarded by previously deployed intermediaries. will be blindly forwarded by previously deployed intermediaries.
The Connection header field's value has the following grammar: The Connection header field's value has the following grammar:
Connection = 1#connection-token Connection = 1#connection-option
connection-token = token connection-option = token
Connection options are compared case-insensitively.
A proxy or gateway MUST parse a received Connection header field A proxy or gateway MUST parse a received Connection header field
before a message is forwarded and, for each connection-token in this before a message is forwarded and, for each connection-option in this
field, remove any header field(s) from the message with the same name field, remove any header field(s) from the message with the same name
as the connection-token, and then remove the Connection header field as the connection-option, and then remove the Connection header field
itself or replace it with the sender's own connection options for the itself or replace it with the sender's own connection options for the
forwarded message. forwarded message.
A sender MUST NOT include field-names in the Connection header field- A sender MUST NOT include field-names in the Connection header field-
value for fields that are defined as expressing constraints for all value for fields that are defined as expressing constraints for all
recipients in the request or response chain, such as the Cache- recipients in the request or response chain, such as the Cache-
Control header field (Section 3.2 of [Part6]). Control header field (Section 7.2 of [Part6]).
The connection options do not have to correspond to a header field The connection options do not have to correspond to a header field
present in the message, since a connection-specific header field present in the message, since a connection-specific header field
might not be needed if there are no parameters associated with that might not be needed if there are no parameters associated with that
connection option. Recipients that trigger certain connection connection option. Recipients that trigger certain connection
behavior based on the presence of connection options MUST do so based behavior based on the presence of connection options MUST do so based
on the presence of the connection-token rather than only the presence on the presence of the connection-option rather than only the
of the optional header field. In other words, if the connection presence of the optional header field. In other words, if the
option is received as a header field but not indicated within the connection option is received as a header field but not indicated
Connection field-value, then the recipient MUST ignore the within the Connection field-value, then the recipient MUST ignore the
connection-specific header field because it has likely been forwarded connection-specific header field because it has likely been forwarded
by an intermediary that is only partially conformant. by an intermediary that is only partially conformant.
When defining new connection options, specifications ought to When defining new connection options, specifications ought to
carefully consider existing deployed header fields and ensure that carefully consider existing deployed header fields and ensure that
the new connection-token does not share the same name as an unrelated the new connection option does not share the same name as an
header field that might already be deployed. Defining a new unrelated header field that might already be deployed. Defining a
connection-token essentially reserves that potential field-name for new connection option essentially reserves that potential field-name
carrying additional information related to the connection option, for carrying additional information related to the connection option,
since it would be unwise for senders to use that field-name for since it would be unwise for senders to use that field-name for
anything else. anything else.
HTTP/1.1 defines the "close" connection option for the sender to HTTP/1.1 defines the "close" connection option for the sender to
signal that the connection will be closed after completion of the signal that the connection will be closed after completion of the
response. For example, response. For example,
Connection: close Connection: close
in either the request or the response header fields indicates that in either the request or the response header fields indicates that
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Persistent connections provide a mechanism by which a client and a Persistent connections provide a mechanism by which a client and a
server can signal the close of a TCP connection. This signaling server can signal the close of a TCP connection. This signaling
takes place using the Connection header field (Section 6.1). Once a takes place using the Connection header field (Section 6.1). Once a
close has been signaled, the client MUST NOT send any more requests close has been signaled, the client MUST NOT send any more requests
on that connection. on that connection.
6.3.2.1. Negotiation 6.3.2.1. Negotiation
An HTTP/1.1 server MAY assume that a HTTP/1.1 client intends to An HTTP/1.1 server MAY assume that a HTTP/1.1 client intends to
maintain a persistent connection unless a Connection header field maintain a persistent connection unless a Connection header field
including the connection-token "close" was sent in the request. If including the connection option "close" was sent in the request. If
the server chooses to close the connection immediately after sending the server chooses to close the connection immediately after sending
the response, it SHOULD send a Connection header field including the the response, it SHOULD send a Connection header field including the
connection-token "close". connection option "close".
An HTTP/1.1 client MAY expect a connection to remain open, but would An HTTP/1.1 client MAY expect a connection to remain open, but would
decide to keep it open based on whether the response from a server decide to keep it open based on whether the response from a server
contains a Connection header field with the connection-token close. contains a Connection header field with the connection option
In case the client does not want to maintain a connection for more "close". In case the client does not want to maintain a connection
than that request, it SHOULD send a Connection header field including for more than that request, it SHOULD send a Connection header field
the connection-token close. including the connection option "close".
If either the client or the server sends the close token in the If either the client or the server sends the "close" option in the
Connection header field, that request becomes the last one for the Connection header field, that request becomes the last one for the
connection. connection.
Clients and servers SHOULD NOT assume that a persistent connection is Clients and servers SHOULD NOT assume that a persistent connection is
maintained for HTTP versions less than 1.1 unless it is explicitly maintained for HTTP versions less than 1.1 unless it is explicitly
signaled. See Appendix A.1.2 for more information on backward signaled. See Appendix A.1.2 for more information on backward
compatibility with HTTP/1.0 clients. compatibility with HTTP/1.0 clients.
Each persistent connection applies to only one transport link. Each persistent connection applies to only one transport link.
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Clients which assume persistent connections and pipeline immediately Clients which assume persistent connections and pipeline immediately
after connection establishment SHOULD be prepared to retry their after connection establishment SHOULD be prepared to retry their
connection if the first pipelined attempt fails. If a client does connection if the first pipelined attempt fails. If a client does
such a retry, it MUST NOT pipeline before it knows the connection is such a retry, it MUST NOT pipeline before it knows the connection is
persistent. Clients MUST also be prepared to resend their requests persistent. Clients MUST also be prepared to resend their requests
if the server closes the connection before sending all of the if the server closes the connection before sending all of the
corresponding responses. corresponding responses.
Clients SHOULD NOT pipeline requests using non-idempotent request Clients SHOULD NOT pipeline requests using non-idempotent request
methods or non-idempotent sequences of request methods (see Section methods or non-idempotent sequences of request methods (see Section
6.1.2 of [Part2]). Otherwise, a premature termination of the 2.1.2 of [Part2]). Otherwise, a premature termination of the
transport connection could lead to indeterminate results. A client transport connection could lead to indeterminate results. A client
wishing to send a non-idempotent request SHOULD wait to send that wishing to send a non-idempotent request SHOULD wait to send that
request until it has received the response status line for the request until it has received the response status line for the
previous request. previous request.
6.3.3. Practical Considerations 6.3.3. Practical Considerations
Servers will usually have some time-out value beyond which they will Servers will usually have some time-out value beyond which they will
no longer maintain an inactive connection. Proxy servers might make no longer maintain an inactive connection. Proxy servers might make
this a higher value since it is likely that the client will be making this a higher value since it is likely that the client will be making
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Note that servers might reject traffic that they deem abusive, Note that servers might reject traffic that they deem abusive,
including an excessive number of connections from a client. including an excessive number of connections from a client.
6.3.4. Retrying Requests 6.3.4. Retrying Requests
Senders can close the transport connection at any time. Therefore, Senders can close the transport connection at any time. Therefore,
clients, servers, and proxies MUST be able to recover from clients, servers, and proxies MUST be able to recover from
asynchronous close events. Client software MAY reopen the transport asynchronous close events. Client software MAY reopen the transport
connection and retransmit the aborted sequence of requests without connection and retransmit the aborted sequence of requests without
user interaction so long as the request sequence is idempotent (see user interaction so long as the request sequence is idempotent (see
Section 6.1.2 of [Part2]). Non-idempotent request methods or Section 2.1.2 of [Part2]). Non-idempotent request methods or
sequences MUST NOT be automatically retried, although user agents MAY sequences MUST NOT be automatically retried, although user agents MAY
offer a human operator the choice of retrying the request(s). offer a human operator the choice of retrying the request(s).
Confirmation by user-agent software with semantic understanding of Confirmation by user-agent software with semantic understanding of
the application MAY substitute for user confirmation. The automatic the application MAY substitute for user confirmation. The automatic
retry SHOULD NOT be repeated if the second sequence of requests retry SHOULD NOT be repeated if the second sequence of requests
fails. fails.
6.4. Message Transmission Requirements 6.4. Message Transmission Requirements
6.4.1. Persistent Connections and Flow Control 6.4.1. Persistent Connections and Flow Control
HTTP/1.1 servers SHOULD maintain persistent connections and use TCP's HTTP/1.1 servers SHOULD maintain persistent connections and use TCP's
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the network connection for an error status code while it is the network connection for an error status code while it is
transmitting the request. If the client sees an error status code, transmitting the request. If the client sees an error status code,
it SHOULD immediately cease transmitting the body. If the body is it SHOULD immediately cease transmitting the body. If the body is
being sent using a "chunked" encoding (Section 4), a zero length being sent using a "chunked" encoding (Section 4), a zero length
chunk and empty trailer MAY be used to prematurely mark the end of chunk and empty trailer MAY be used to prematurely mark the end of
the message. If the body was preceded by a Content-Length header the message. If the body was preceded by a Content-Length header
field, the client MUST close the connection. field, the client MUST close the connection.
6.4.3. Use of the 100 (Continue) Status 6.4.3. Use of the 100 (Continue) Status
The purpose of the 100 (Continue) status code (see Section 7.1.1 of The purpose of the 100 (Continue) status code (see Section 4.3.1 of
[Part2]) is to allow a client that is sending a request message with [Part2]) is to allow a client that is sending a request message with
a request body to determine if the origin server is willing to accept a request body to determine if the origin server is willing to accept
the request (based on the request header fields) before the client the request (based on the request header fields) before the client
sends the request body. In some cases, it might either be sends the request body. In some cases, it might either be
inappropriate or highly inefficient for the client to send the body inappropriate or highly inefficient for the client to send the body
if the server will reject the message without looking at the body. if the server will reject the message without looking at the body.
Requirements for HTTP/1.1 clients: Requirements for HTTP/1.1 clients:
o If a client will wait for a 100 (Continue) response before sending o If a client will wait for a 100 (Continue) response before sending
the request body, it MUST send an Expect header field (Section the request body, it MUST send an Expect header field (Section
10.3 of [Part2]) with the "100-continue" expectation. 9.11 of [Part2]) with the "100-continue" expectation.
o A client MUST NOT send an Expect header field (Section 10.3 of o A client MUST NOT send an Expect header field with the "100-
[Part2]) with the "100-continue" expectation if it does not intend continue" expectation if it does not intend to send a request
to send a request body. body.
Because of the presence of older implementations, the protocol allows Because of the presence of older implementations, the protocol allows
ambiguous situations in which a client might send "Expect: 100- ambiguous situations in which a client might send "Expect: 100-
continue" without receiving either a 417 (Expectation Failed) or a continue" without receiving either a 417 (Expectation Failed) or a
100 (Continue) status code. Therefore, when a client sends this 100 (Continue) status code. Therefore, when a client sends this
header field to an origin server (possibly via a proxy) from which it header field to an origin server (possibly via a proxy) from which it
has never seen a 100 (Continue) status code, the client SHOULD NOT has never seen a 100 (Continue) status code, the client SHOULD NOT
wait for an indefinite period before sending the request body. wait for an indefinite period before sending the request body.
Requirements for HTTP/1.1 origin servers: Requirements for HTTP/1.1 origin servers:
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HTTP/1.0 or lower, it MUST NOT forward the request, and it MUST HTTP/1.0 or lower, it MUST NOT forward the request, and it MUST
respond with a 417 (Expectation Failed) status code. respond with a 417 (Expectation Failed) status code.
o Proxies SHOULD maintain a record of the HTTP version numbers o Proxies SHOULD maintain a record of the HTTP version numbers
received from recently-referenced next-hop servers. received from recently-referenced next-hop servers.
o A proxy MUST NOT forward a 100 (Continue) response if the request o A proxy MUST NOT forward a 100 (Continue) response if the request
message was received from an HTTP/1.0 (or earlier) client and did message was received from an HTTP/1.0 (or earlier) client and did
not include an Expect header field with the "100-continue" not include an Expect header field with the "100-continue"
expectation. This requirement overrides the general rule for expectation. This requirement overrides the general rule for
forwarding of 1xx responses (see Section 7.1 of [Part2]). forwarding of 1xx responses (see Section 4.3 of [Part2]).
6.4.4. Closing Connections on Error 6.4.4. Closing Connections on Error
If the client is sending data, a server implementation using TCP If the client is sending data, a server implementation using TCP
SHOULD be careful to ensure that the client acknowledges receipt of SHOULD be careful to ensure that the client acknowledges receipt of
the packet(s) containing the response, before the server closes the the packet(s) containing the response, before the server closes the
input connection. If the client continues sending data to the server input connection. If the client continues sending data to the server
after the close, the server's TCP stack will send a reset packet to after the close, the server's TCP stack will send a reset packet to
the client, which might erase the client's unacknowledged input the client, which might erase the client's unacknowledged input
buffers before they can be read and interpreted by the HTTP buffers before they can be read and interpreted by the HTTP
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after changing the protocol MUST be a response to the initial HTTP after changing the protocol MUST be a response to the initial HTTP
request containing the Upgrade header field. request containing the Upgrade header field.
The Upgrade header field only applies to the immediate connection. The Upgrade header field only applies to the immediate connection.
Therefore, the upgrade keyword MUST be supplied within a Connection Therefore, the upgrade keyword MUST be supplied within a Connection
header field (Section 6.1) whenever Upgrade is present in an HTTP/1.1 header field (Section 6.1) whenever Upgrade is present in an HTTP/1.1
message. message.
The Upgrade header field cannot be used to indicate a switch to a The Upgrade header field cannot be used to indicate a switch to a
protocol on a different connection. For that purpose, it is more protocol on a different connection. For that purpose, it is more
appropriate to use a 3xx redirection response (Section 7.3 of appropriate to use a 3xx (Redirection) response (Section 4.5 of
[Part2]). [Part2]).
Servers MUST include the "Upgrade" header field in 101 (Switching Servers MUST include the "Upgrade" header field in 101 (Switching
Protocols) responses to indicate which protocol(s) are being switched Protocols) responses to indicate which protocol(s) are being switched
to, and MUST include it in 426 (Upgrade Required) responses to to, and MUST include it in 426 (Upgrade Required) responses to
indicate acceptable protocols to upgrade to. Servers MAY include it indicate acceptable protocols to upgrade to. Servers MAY include it
in any other response to indicate that they are willing to upgrade to in any other response to indicate that they are willing to upgrade to
one of the specified protocols. one of the specified protocols.
This specification only defines the protocol name "HTTP" for use by This specification only defines the protocol name "HTTP" for use by
the family of Hypertext Transfer Protocols, as defined by the HTTP the family of Hypertext Transfer Protocols, as defined by the HTTP
version rules of Section 2.6 and future updates to this version rules of Section 2.7 and future updates to this
specification. Additional tokens can be registered with IANA using specification. Additional tokens can be registered with IANA using
the registration procedure defined in Section 7.6. the registration procedure defined in Section 7.6.
7. IANA Considerations 7. IANA Considerations
7.1. Header Field Registration 7.1. Header Field Registration
HTTP header fields are registered within the Message Header Field HTTP header fields are registered within the Message Header Field
Registry [RFC3864] maintained by IANA at <http://www.iana.org/ Registry [RFC3864] maintained by IANA at <http://www.iana.org/
assignments/message-headers/message-header-index.html>. assignments/message-headers/message-header-index.html>.
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IANA maintains the registry of URI Schemes [RFC4395] at IANA maintains the registry of URI Schemes [RFC4395] at
<http://www.iana.org/assignments/uri-schemes.html>. <http://www.iana.org/assignments/uri-schemes.html>.
This document defines the following URI schemes, so their associated This document defines the following URI schemes, so their associated
registry entries shall be updated according to the permanent registry entries shall be updated according to the permanent
registrations below: registrations below:
+------------+------------------------------------+---------------+ +------------+------------------------------------+---------------+
| URI Scheme | Description | Reference | | URI Scheme | Description | Reference |
+------------+------------------------------------+---------------+ +------------+------------------------------------+---------------+
| http | Hypertext Transfer Protocol | Section 2.7.1 | | http | Hypertext Transfer Protocol | Section 2.8.1 |
| https | Hypertext Transfer Protocol Secure | Section 2.7.2 | | https | Hypertext Transfer Protocol Secure | Section 2.8.2 |
+------------+------------------------------------+---------------+ +------------+------------------------------------+---------------+
7.3. Internet Media Type Registrations 7.3. Internet Media Type Registrations
This document serves as the specification for the Internet media This document serves as the specification for the Internet media
types "message/http" and "application/http". The following is to be types "message/http" and "application/http". The following is to be
registered with IANA (see [RFC4288]). registered with IANA (see [RFC4288]).
7.3.1. Internet Media Type message/http 7.3.1. Internet Media Type message/http
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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 transfer codings MUST NOT overlap with names of content Names of transfer codings MUST NOT overlap with names of content
codings (Section 2.2 of [Part3]) unless the encoding transformation codings (Section 5.4 of [Part2]) unless the encoding transformation
is identical, as it is the case for the compression codings defined is identical, as it is the case for the compression codings defined
in Section 4.2. in Section 4.2.
Values to be added to this name space require IETF Review (see Values to be added to this name space require IETF Review (see
Section 4.1 of [RFC5226]), and MUST conform to the purpose of Section 4.1 of [RFC5226]), and MUST conform to the purpose of
transfer coding defined in this section. transfer 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>.
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| deflate | "deflate" compression mechanism | Section 4.2.2 | | deflate | "deflate" compression mechanism | Section 4.2.2 |
| | ([RFC1951]) used inside the "zlib" | | | | ([RFC1951]) used inside the "zlib" | |
| | data format ([RFC1950]) | | | | data format ([RFC1950]) | |
| gzip | Same as GNU zip [RFC1952] | Section 4.2.3 | | gzip | Same as GNU zip [RFC1952] | Section 4.2.3 |
+----------+----------------------------------------+---------------+ +----------+----------------------------------------+---------------+
7.6. Upgrade Token Registry 7.6. Upgrade Token Registry
The HTTP Upgrade Token Registry defines the name space for protocol- The HTTP Upgrade Token Registry defines the name space for protocol-
name tokens used to identify protocols in the Upgrade header field. name tokens used to identify protocols in the Upgrade header field.
Each registered protocol-name is associated with contact information Each registered protocol name is associated with contact information
and an optional set of specifications that details how the connection and an optional set of specifications that details how the connection
will be processed after it has been upgraded. will be processed after it has been upgraded.
Registrations require IETF Review (see Section 4.1 of [RFC5226]) and Registrations happen on a "First Come First Served" basis (see
are subject to the following rules: Section 4.1 of [RFC5226]) and are subject to the following rules:
1. A protocol-name token, once registered, stays registered forever. 1. A protocol-name token, once registered, stays registered forever.
2. The registration MUST name a responsible party for the 2. The registration MUST name a responsible party for the
registration. registration.
3. The registration MUST name a point of contact. 3. The registration MUST name a point of contact.
4. The registration MAY name a set of specifications associated with 4. The registration MAY name a set of specifications associated with
that token. Such specifications need not be publicly available. that token. Such specifications need not be publicly available.
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7.7. Upgrade Token Registration 7.7. Upgrade Token Registration
The HTTP Upgrade Token Registry shall be updated with the The HTTP Upgrade Token Registry shall be updated with the
registration below: registration below:
+-------+----------------------+----------------------+-------------+ +-------+----------------------+----------------------+-------------+
| Value | Description | Expected Version | Reference | | Value | Description | Expected Version | Reference |
| | | Tokens | | | | | Tokens | |
+-------+----------------------+----------------------+-------------+ +-------+----------------------+----------------------+-------------+
| HTTP | Hypertext Transfer | any DIGIT.DIGIT | Section 2.6 | | HTTP | Hypertext Transfer | any DIGIT.DIGIT | Section 2.7 |
| | Protocol | (e.g, "2.0") | | | | Protocol | (e.g, "2.0") | |
+-------+----------------------+----------------------+-------------+ +-------+----------------------+----------------------+-------------+
The responsible party is: "IETF (iesg@ietf.org) - Internet The responsible party is: "IETF (iesg@ietf.org) - Internet
Engineering Task Force". Engineering Task Force".
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
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some suggestions for reducing security risks. some suggestions for reducing security risks.
8.1. Personal Information 8.1. Personal Information
HTTP clients are often privy to large amounts of personal information HTTP clients are often privy to large amounts of personal information
(e.g., the user's name, location, mail address, passwords, encryption (e.g., the user's name, location, mail address, passwords, encryption
keys, etc.), and SHOULD be very careful to prevent unintentional keys, etc.), and SHOULD be very careful to prevent unintentional
leakage of this information. We very strongly recommend that a leakage of this information. We very strongly recommend that a
convenient interface be provided for the user to control convenient interface be provided for the user to control
dissemination of such information, and that designers and dissemination of such information, and that designers and
implementors be particularly careful in this area. History shows implementers be particularly careful in this area. History shows
that errors in this area often create serious security and/or privacy that errors in this area often create serious security and/or privacy
problems and generate highly adverse publicity for the implementor's problems and generate highly adverse publicity for the implementer's
company. company.
8.2. Abuse of Server Log Information 8.2. Abuse of Server Log Information
A server is in the position to save personal data about a user's A server is in the position to save personal data about a user's
requests which might identify their reading patterns or subjects of requests which might identify their reading patterns or subjects of
interest. In particular, log information gathered at an intermediary interest. In particular, log information gathered at an intermediary
often contains a history of user agent interaction, across a often contains a history of user agent interaction, across a
multitude of sites, that can be traced to individual users. multitude of sites, that can be traced to individual users.
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security-related information, personal information about individual security-related information, personal information about individual
users and organizations, and proprietary information belonging to users and organizations, and proprietary information belonging to
users and content providers. A compromised intermediary, or an users and content providers. A compromised intermediary, or an
intermediary implemented or configured without regard to security and intermediary implemented or configured without regard to security and
privacy considerations, might be used in the commission of a wide privacy considerations, might be used in the commission of a wide
range of potential attacks. range of potential attacks.
Intermediaries that contain a shared cache are especially vulnerable Intermediaries that contain a shared cache are especially vulnerable
to cache poisoning attacks. to cache poisoning attacks.
Implementors need to consider the privacy and security implications Implementers need to consider the privacy and security implications
of their design and coding decisions, and of the configuration of their design and coding decisions, and of the configuration
options they provide to operators (especially the default options they provide to operators (especially the default
configuration). configuration).
Users need to be aware that intermediaries are no more trustworthy Users need to be aware that intermediaries are no more trustworthy
than the people who run them; HTTP itself cannot solve this problem. than the people who run them; HTTP itself cannot solve this problem.
The judicious use of cryptography, when appropriate, might suffice to The judicious use of cryptography, when appropriate, might suffice to
protect against a broad range of security and privacy attacks. Such protect against a broad range of security and privacy attacks. Such
cryptography is beyond the scope of the HTTP/1.1 specification. cryptography is beyond the scope of the HTTP/1.1 specification.
skipping to change at page 65, line 42 skipping to change at page 66, line 8
unlimited lengths. unlimited lengths.
To promote interoperability, this specification makes specific To promote interoperability, this specification makes specific
recommendations for minimum size limits on request-line recommendations for minimum size limits on request-line
(Section 3.1.1) and blocks of header fields (Section 3.2). These are (Section 3.1.1) and blocks of header fields (Section 3.2). These are
minimum recommendations, chosen to be supportable even by minimum recommendations, chosen to be supportable even by
implementations with limited resources; it is expected that most implementations with limited resources; it is expected that most
implementations will choose substantially higher limits. implementations will choose substantially higher limits.
This specification also provides a way for servers to reject messages This specification also provides a way for servers to reject messages
that have request-targets that are too long (Section 7.4.12 of that have request-targets that are too long (Section 4.6.12 of
[Part2]) or request entities that are too large (Section 7.4 of [Part2]) or request entities that are too large (Section 4.6 of
[Part2]). [Part2]).
Other fields (including but not limited to request methods, response Other fields (including but not limited to request methods, response
status phrases, header field-names, and body chunks) SHOULD be status phrases, header field-names, and body chunks) SHOULD be
limited by implementations carefully, so as to not impede limited by implementations carefully, so as to not impede
interoperability. interoperability.
9. Acknowledgments 9. Acknowledgments
This edition of HTTP builds on the many contributions that went into This edition of HTTP builds on the many contributions that went into
skipping to change at page 66, line 19 skipping to change at page 66, line 31
contributions made by the previous authors, editors, and working contributions made by the previous authors, editors, and working
group chairs: Tim Berners-Lee, Ari Luotonen, Roy T. Fielding, Henrik group chairs: Tim Berners-Lee, Ari Luotonen, Roy T. Fielding, Henrik
Frystyk Nielsen, Jim Gettys, Jeffrey C. Mogul, Larry Masinter, Paul Frystyk Nielsen, Jim Gettys, Jeffrey C. Mogul, Larry Masinter, Paul
J. Leach, and Mark Nottingham. See Section 16 of [RFC2616] for J. Leach, and Mark Nottingham. See Section 16 of [RFC2616] for
additional acknowledgements from prior revisions. additional acknowledgements from prior revisions.
Since 1999, the following contributors have helped improve the HTTP Since 1999, the following contributors have helped improve the HTTP
specification by reporting bugs, asking smart questions, drafting or specification by reporting bugs, asking smart questions, drafting or
reviewing text, and evaluating open issues: reviewing text, and evaluating open issues:
Adam Barth, Adam Roach, Addison Phillips, Adrian Chadd, Adrien de Adam Barth, Adam Roach, Addison Phillips, Adrian Chadd, Adrien W. de
Croy, Alan Ford, Alan Ruttenberg, Albert Lunde, Alex Rousskov, Alexey Croy, Alan Ford, Alan Ruttenberg, Albert Lunde, Alek Storm, Alex
Melnikov, Alisha Smith, Amichai Rothman, Amit Klein, Amos Jeffries, Rousskov, Alexandre Morgaut, Alexey Melnikov, Alisha Smith, Amichai
Andreas Maier, Andreas Petersson, Anne van Kesteren, Anthony Bryan, Rothman, Amit Klein, Amos Jeffries, Andreas Maier, Andreas Petersson,
Asbjorn Ulsberg, Balachander Krishnamurthy, Barry Leiba, Ben Laurie, Anne van Kesteren, Anthony Bryan, Asbjorn Ulsberg, Balachander
Benjamin Niven-Jenkins, Bil Corry, Bill Burke, Bjoern Hoehrmann, Bob Krishnamurthy, Barry Leiba, Ben Laurie, Benjamin Niven-Jenkins, Bil
Scheifler, Boris Zbarsky, Brett Slatkin, Brian Kell, Brian McBarron, Corry, Bill Burke, Bjoern Hoehrmann, Bob Scheifler, Boris Zbarsky,
Brian Pane, Brian Smith, Bryce Nesbitt, Cameron Heavon-Jones, Carl Brett Slatkin, Brian Kell, Brian McBarron, Brian Pane, Brian Smith,
Kugler, Carsten Bormann, Charles Fry, Chris Newman, Cyrus Daboo, Dale Bryce Nesbitt, Cameron Heavon-Jones, Carl Kugler, Carsten Bormann,
Robert Anderson, Dan Winship, Daniel Stenberg, Dave Cridland, Dave Charles Fry, Chris Newman, Cyrus Daboo, Dale Robert Anderson, Dan
Crocker, Dave Kristol, David Booth, David Singer, David W. Morris, Winship, Daniel Stenberg, Dave Cridland, Dave Crocker, Dave Kristol,
Diwakar Shetty, Dmitry Kurochkin, Drummond Reed, Duane Wessels, David Booth, David Singer, David W. Morris, Diwakar Shetty, Dmitry
Edward Lee, Eliot Lear, Eran Hammer-Lahav, Eric D. Williams, Eric J. Kurochkin, Drummond Reed, Duane Wessels, Edward Lee, Eliot Lear, Eran
Bowman, Eric Lawrence, Eric Rescorla, Erik Aronesty, Florian Weimer, Hammer-Lahav, Eric D. Williams, Eric J. Bowman, Eric Lawrence, Eric
Frank Ellermann, Fred Bohle, Geoffrey Sneddon, Gervase Markham, Greg Rescorla, Erik Aronesty, Florian Weimer, Frank Ellermann, Fred Bohle,
Wilkins, Harald Tveit Alvestrand, Harry Halpin, Helge Hess, Henrik Geoffrey Sneddon, Gervase Markham, Greg Wilkins, Harald Tveit
Nordstrom, Henry S. Thompson, Henry Story, Herbert van de Sompel, Alvestrand, Harry Halpin, Helge Hess, Henrik Nordstrom, Henry S.
Howard Melman, Hugo Haas, Ian Hickson, Ingo Struck, J. Ross Nicoll, Thompson, Henry Story, Herbert van de Sompel, Howard Melman, Hugo
James H. Manger, James Lacey, James M. Snell, Jamie Lokier, Jan Haas, Ian Hickson, Ingo Struck, J. Ross Nicoll, James H. Manger,
Algermissen, Jeff Hodges (for coming up with the term 'effective James Lacey, James M. Snell, Jamie Lokier, Jan Algermissen, Jeff
Request-URI'), Jeff Walden, Jim Luther, Joe D. Williams, Joe Hodges (who came up with the term 'effective Request-URI'), Jeff
Gregorio, Joe Orton, John C. Klensin, John C. Mallery, John Cowan, Walden, Jim Luther, Joe D. Williams, Joe Gregorio, Joe Orton, John C.
John Kemp, John Panzer, John Schneider, John Stracke, Jonas Sicking, Klensin, John C. Mallery, John Cowan, John Kemp, John Panzer, John
Jonathan Billington, Jonathan Moore, Jonathan Rees, Jordi Ros, Joris Schneider, John Stracke, John Sullivan, Jonas Sicking, Jonathan
Dobbelsteen, Josh Cohen, Julien Pierre, Jungshik Shin, Justin Billington, Jonathan Moore, Jonathan Rees, Jonathan Silvera, Jordi
Chapweske, Justin Erenkrantz, Justin James, Kalvinder Singh, Karl Ros, Joris Dobbelsteen, Josh Cohen, Julien Pierre, Jungshik Shin,
Dubost, Keith Hoffman, Keith Moore, Koen Holtman, Konstantin Justin Chapweske, Justin Erenkrantz, Justin James, Kalvinder Singh,
Karl Dubost, Keith Hoffman, Keith Moore, Koen Holtman, Konstantin
Voronkov, Kris Zyp, Lisa Dusseault, Maciej Stachowiak, Marc Voronkov, Kris Zyp, Lisa Dusseault, Maciej Stachowiak, Marc
Schneider, Marc Slemko, Mark Baker, Mark Pauley, Markus Lanthaler, Schneider, Marc Slemko, Mark Baker, Mark Pauley, Mark Watson, Markus
Martin J. Duerst, Martin Thomson, Matt Lynch, Matthew Cox, Max Clark, Isomaki, Markus Lanthaler, Martin J. Duerst, Martin Musatov, Martin
Michael Burrows, Michael Hausenblas, Mike Amundsen, Mike Belshe, Mike Nilsson, Martin Thomson, Matt Lynch, Matthew Cox, Max Clark, Michael
Kelly, Mike Schinkel, Miles Sabin, Mykyta Yevstifeyev, Nathan Rixham, Burrows, Michael Hausenblas, Mike Amundsen, Mike Belshe, Mike Kelly,
Nicholas Shanks, Nico Williams, Nicolas Alvarez, Nicolas Mailhot, Mike Schinkel, Miles Sabin, Murray S. Kucherawy, Mykyta Yevstifeyev,
Noah Slater, Pablo Castro, Pat Hayes, Patrick R. McManus, Paul E. Nathan Rixham, Nicholas Shanks, Nico Williams, Nicolas Alvarez,
Nicolas Mailhot, Noah Slater, Pablo Castro, Pat Hayes, Patrick R.
Jones, Paul Hoffman, Paul Marquess, Peter Saint-Andre, Peter Watkins, McManus, Paul E. Jones, Paul Hoffman, Paul Marquess, Peter Lepeska,
Phil Archer, Phillip Hallam-Baker, Poul-Henning Kamp, Preethi Peter Saint-Andre, Peter Watkins, Phil Archer, Phillip Hallam-Baker,
Natarajan, Ray Polk, Reto Bachmann-Gmuer, Richard Cyganiak, Robert Poul-Henning Kamp, Preethi Natarajan, Ray Polk, Reto Bachmann-Gmuer,
Brewer, Robert Collins, Robert O'Callahan, Robert Olofsson, Robert Richard Cyganiak, Robert Brewer, Robert Collins, Robert O'Callahan,
Sayre, Robert Siemer, Robert de Wilde, Roberto Javier Godoy, Ronny Robert Olofsson, Robert Sayre, Robert Siemer, Robert de Wilde,
Widjaja, S. Mike Dierken, Salvatore Loreto, Sam Johnston, Sam Ruby, Roberto Javier Godoy, Roberto Peon, Ronny Widjaja, S. Mike Dierken,
Scott Lawrence (for maintaining the original issues list), Sean B. Salvatore Loreto, Sam Johnston, Sam Ruby, Scott Lawrence (who
Palmer, Shane McCarron, Stefan Eissing, Stefan Tilkov, Stefanos maintained the original issues list), Sean B. Palmer, Shane McCarron,
Harhalakis, Stephane Bortzmeyer, Stephen Farrell, Stuart Williams, Stefan Eissing, Stefan Tilkov, Stefanos Harhalakis, Stephane
Subbu Allamaraju, Sylvain Hellegouarch, Tapan Divekar, Ted Hardie, Bortzmeyer, Stephen Farrell, Stephen Ludin, Stuart Williams, Subbu
Thomas Broyer, Thomas Nordin, Thomas Roessler, Tim Morgan, Tim Olsen, Allamaraju, Sylvain Hellegouarch, Tapan Divekar, Tatsuya Hayashi, Ted
Travis Snoozy, Tyler Close, Vincent Murphy, Wenbo Zhu, Werner Hardie, Thomas Broyer, Thomas Nordin, Thomas Roessler, Tim Bray, Tim
Baumann, Wilbur Streett, Wilfredo Sanchez Vega, William A. Rowe Jr., Morgan, Tim Olsen, Tom Zhou, Travis Snoozy, Tyler Close, Vincent
William Chan, Willy Tarreau, Xiaoshu Wang, Yaron Goland, Yngve Murphy, Wenbo Zhu, Werner Baumann, Wilbur Streett, Wilfredo Sanchez
Nysaeter Pettersen, Yogesh Bang, Yutaka Oiwa, Zed A. Shaw, and Zhong Vega, William A. Rowe Jr., William Chan, Willy Tarreau, Xiaoshu Wang,
Yu. Yaron Goland, Yngve Nysaeter Pettersen, Yoav Nir, Yogesh Bang, Yutaka
Oiwa, Zed A. Shaw, and Zhong Yu.
10. References 10. References
10.1. Normative References 10.1. Normative References
[ISO-8859-1] International Organization for Standardization,
"Information technology -- 8-bit single-byte coded
graphic character sets -- Part 1: Latin alphabet No.
1", ISO/IEC 8859-1:1998, 1998.
[Part2] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., [Part2] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"HTTP/1.1, part 2: Message Semantics", "HTTP/1.1, part 2: Semantics and Payloads",
draft-ietf-httpbis-p2-semantics-19 (work in progress), draft-ietf-httpbis-p2-semantics-20 (work in progress),
March 2012. July 2012.
[Part3] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., [Part4] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"HTTP/1.1, part 3: Message Payload and Content "HTTP/1.1, part 4: Conditional Requests",
Negotiation", draft-ietf-httpbis-p3-payload-19 (work in draft-ietf-httpbis-p4-conditional-20 (work in
progress), March 2012. progress), July 2012.
[Part5] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"HTTP/1.1, part 5: Range Requests",
draft-ietf-httpbis-p5-range-20 (work in progress),
July 2012.
[Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed., [Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed.,
and J. Reschke, Ed., "HTTP/1.1, part 6: Caching", and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",
draft-ietf-httpbis-p6-cache-19 (work in progress), draft-ietf-httpbis-p6-cache-20 (work in progress),
March 2012. July 2012.
[Part7] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"HTTP/1.1, part 7: Authentication",
draft-ietf-httpbis-p7-auth-20 (work in progress),
July 2012.
[RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data [RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data
Format Specification version 3.3", RFC 1950, May 1996. Format Specification version 3.3", RFC 1950, May 1996.
[RFC1951] Deutsch, P., "DEFLATE Compressed Data Format [RFC1951] Deutsch, P., "DEFLATE Compressed Data Format
Specification version 1.3", RFC 1951, May 1996. Specification version 1.3", RFC 1951, May 1996.
[RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and [RFC1952] Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and
G. Randers-Pehrson, "GZIP file format specification G. Randers-Pehrson, "GZIP file format specification
version 4.3", RFC 1952, May 1996. version 4.3", RFC 1952, May 1996.
skipping to change at page 68, line 24 skipping to change at page 68, line 45
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for
Syntax Specifications: ABNF", STD 68, RFC 5234, Syntax Specifications: ABNF", STD 68, RFC 5234,
January 2008. January 2008.
[USASCII] American National Standards Institute, "Coded Character [USASCII] American National Standards Institute, "Coded Character
Set -- 7-bit American Standard Code for Information Set -- 7-bit American Standard Code for Information
Interchange", ANSI X3.4, 1986. Interchange", ANSI X3.4, 1986.
10.2. Informative References 10.2. Informative References
[ISO-8859-1] International Organization for Standardization,
"Information technology -- 8-bit single-byte coded
graphic character sets -- Part 1: Latin alphabet No.
1", ISO/IEC 8859-1:1998, 1998.
[Kri2001] Kristol, D., "HTTP Cookies: Standards, Privacy, and [Kri2001] Kristol, D., "HTTP Cookies: Standards, Privacy, and
Politics", ACM Transactions on Internet Technology Vol. Politics", ACM Transactions on Internet Technology Vol.
1, #2, November 2001, 1, #2, November 2001,
<http://arxiv.org/abs/cs.SE/0105018>. <http://arxiv.org/abs/cs.SE/0105018>.
[Nie1997] Frystyk, H., Gettys, J., Prud'hommeaux, E., Lie, H., [Nie1997] Frystyk, H., Gettys, J., Prud'hommeaux, E., Lie, H.,
and C. Lilley, "Network Performance Effects of and C. Lilley, "Network Performance Effects of
HTTP/1.1, CSS1, and PNG", ACM Proceedings of the ACM HTTP/1.1, CSS1, and PNG", ACM Proceedings of the ACM
SIGCOMM '97 conference on Applications, technologies, SIGCOMM '97 conference on Applications, technologies,
architectures, and protocols for computer communication architectures, and protocols for computer communication
SIGCOMM '97, September 1997, SIGCOMM '97, September 1997,
<http://doi.acm.org/10.1145/263105.263157>. <http://doi.acm.org/10.1145/263105.263157>.
skipping to change at page 72, line 5 skipping to change at page 72, line 37
However, some implementations implement the explicitly negotiated However, some implementations implement the explicitly negotiated
("Keep-Alive") version of persistent connections described in Section ("Keep-Alive") version of persistent connections described in Section
19.7.1 of [RFC2068]. 19.7.1 of [RFC2068].
Some clients and servers might wish to be compatible with these Some clients and servers might wish to be compatible with these
previous approaches to persistent connections, by explicitly previous approaches to persistent connections, by explicitly
negotiating for them with a "Connection: keep-alive" request header negotiating for them with a "Connection: keep-alive" request header
field. However, some experimental implementations of HTTP/1.0 field. However, some experimental implementations of HTTP/1.0
persistent connections are faulty; for example, if a HTTP/1.0 proxy persistent connections are faulty; for example, if a HTTP/1.0 proxy
server doesn't understand Connection, it will erroneously forward server doesn't understand Connection, it will erroneously forward
that header to the next inbound server, which would result in a hung that header field to the next inbound server, which would result in a
connection. hung connection.
One attempted solution was the introduction of a Proxy-Connection One attempted solution was the introduction of a Proxy-Connection
header, targeted specifically at proxies. In practice, this was also header field, targeted specifically at proxies. In practice, this
unworkable, because proxies are often deployed in multiple layers, was also unworkable, because proxies are often deployed in multiple
bringing about the same problem discussed above. layers, bringing about the same problem discussed above.
As a result, clients are encouraged not to send the Proxy-Connection As a result, clients are encouraged not to send the Proxy-Connection
header in any requests. header field in any requests.
Clients are also encouraged to consider the use of Connection: keep- Clients are also encouraged to consider the use of Connection: keep-
alive in requests carefully; while they can enable persistent alive in requests carefully; while they can enable persistent
connections with HTTP/1.0 servers, clients using them need will need connections with HTTP/1.0 servers, clients using them need will need
to monitor the connection for "hung" requests (which indicate that to monitor the connection for "hung" requests (which indicate that
the client ought stop sending the header), and this mechanism ought the client ought stop sending the header field), and this mechanism
not be used by clients at all when a proxy is being used. ought not be used by clients at all when a proxy is being used.
A.1.3. Introduction of Transfer-Encoding
HTTP/1.1 introduces the Transfer-Encoding header field
(Section 3.3.1). Proxies/gateways MUST remove any transfer-coding
prior to forwarding a message via a MIME-compliant protocol.
A.2. Changes from RFC 2616 A.2. Changes from RFC 2616
Clarify that the string "HTTP" in the HTTP-version ABFN production is Clarify that the string "HTTP" in the HTTP-version ABNF production is
case sensitive. Restrict the version numbers to be single digits due case sensitive. Restrict the version numbers to be single digits due
to the fact that implementations are known to handle multi-digit to the fact that implementations are known to handle multi-digit
version numbers incorrectly. (Section 2.6) version numbers incorrectly. (Section 2.7)
Update use of abs_path production from RFC 1808 to the path-absolute Update use of abs_path production from RFC 1808 to the path-absolute
+ query components of RFC 3986. State that the asterisk form is + query components of RFC 3986. State that the asterisk form is
allowed for the OPTIONS request method only. (Section 5.3) allowed for the OPTIONS request method only. (Section 5.3)
Require that invalid whitespace around field-names be rejected. Require that invalid whitespace around field-names be rejected.
(Section 3.2) (Section 3.2)
Rules about implicit linear whitespace between certain grammar Rules about implicit linear whitespace between certain grammar
productions have been removed; now whitespace is only allowed where productions have been removed; now whitespace is only allowed where
specifically defined in the ABNF. (Section 3.2.1) specifically defined in the ABNF. (Section 3.2.1)
The NUL octet is no longer allowed in comment and quoted-string text. The NUL octet is no longer allowed in comment and quoted-string text.
The quoted-pair rule no longer allows escaping control characters The quoted-pair rule no longer allows escaping control characters
other than HTAB. Non-ASCII content in header fields and reason other than HTAB. Non-ASCII content in header fields and reason
phrase has been obsoleted and made opaque (the TEXT rule was phrase has been obsoleted and made opaque (the TEXT rule was
removed). (Section 3.2.4) removed). (Section 3.2.4)
Empty list elements in list productions have been deprecated. Empty list elements in list productions have been deprecated.
(Section 3.2.5) (Appendix B)
Require recipients to handle bogus Content-Length header fields as Require recipients to handle bogus Content-Length header fields as
errors. (Section 3.3) errors. (Section 3.3)
Remove reference to non-existent identity transfer-coding value Remove reference to non-existent identity transfer-coding value
tokens. (Sections 3.3 and 4) tokens. (Sections 3.3 and 4)
Clarification that the chunk length does not include the count of the Clarification that the chunk length does not include the count of the
octets in the chunk header and trailer. Furthermore disallowed line octets in the chunk header and trailer. Furthermore disallowed line
folding in chunk extensions, and deprecate their use. (Section 4.1) folding in chunk extensions, and deprecate their use. (Section 4.1)
Registration of Transfer Codings now requires IETF Review Registration of Transfer Codings now requires IETF Review
(Section 7.4) (Section 7.4)
Remove hard limit of two connections per server. Remove requirement Remove hard limit of two connections per server. Remove requirement
to retry a sequence of requests as long it was idempotent. Remove to retry a sequence of requests as long it was idempotent. Remove
requirements about when servers are allowed to close connections requirements about when servers are allowed to close connections
prematurely. (Section 6.3.3) prematurely. (Section 6.3.3)
Remove requirement to retry requests under certain cirumstances when Remove requirement to retry requests under certain circumstances when
the server prematurely closes the connection. (Section 6.4) the server prematurely closes the connection. (Section 6.4)
Change ABNF productions for header fields to only define the field Change ABNF productions for header fields to only define the field
value. value.
Clarify exactly when close connection options must be sent. Clarify exactly when "close" connection options have to be sent.
(Section 6.1) (Section 6.1)
Define the semantics of the "Upgrade" header field in responses other Define the semantics of the Upgrade header field in responses other
than 101 (this was incorporated from [RFC2817]). (Section 6.5) than 101 (this was incorporated from [RFC2817]). (Section 6.5)
A.3. Changes from RFC 2817 Take over the Upgrade Token Registry, previously defined in Section
7.2 of [RFC2817]. (Section 7.6)
Registration of Upgrade tokens now requires IETF Review (Section 7.6) Appendix B. ABNF list extension: #rule
Appendix B. Collected ABNF A #rule extension to the ABNF rules of [RFC5234] is used to improve
readability in the definitions of some header field values.
A construct "#" is defined, similar to "*", for defining comma-
delimited lists of elements. The full form is "<n>#<m>element"
indicating at least <n> and at most <m> elements, each separated by a
single comma (",") and optional whitespace (OWS).
Thus,
1#element => element *( OWS "," OWS element )
and:
#element => [ 1#element ]
and for n >= 1 and m > 1:
<n>#<m>element => element <n-1>*<m-1>( OWS "," OWS element )
For compatibility with legacy list rules, recipients SHOULD accept
empty list elements. In other words, consumers would follow the list
productions:
#element => [ ( "," / element ) *( OWS "," [ OWS element ] ) ]
1#element => *( "," OWS ) element *( OWS "," [ OWS element ] )
Note that empty elements do not contribute to the count of elements
present, though.
For example, given these ABNF productions:
example-list = 1#example-list-elmt
example-list-elmt = token ; see Section 3.2.4
Then these are valid values for example-list (not including the
double quotes, which are present for delimitation only):
"foo,bar"
"foo ,bar,"
"foo , ,bar,charlie "
But these values would be invalid, as at least one non-empty element
is required:
""
","
", ,"
Appendix C shows the collected ABNF, with the list rules expanded as
explained above.
Appendix C. Collected ABNF
BWS = OWS BWS = OWS
Connection = *( "," OWS ) connection-token *( OWS "," [ OWS Connection = *( "," OWS ) connection-option *( OWS "," [ OWS
connection-token ] ) connection-option ] )
Content-Length = 1*DIGIT Content-Length = 1*DIGIT
HTTP-message = start-line *( header-field CRLF ) CRLF [ message-body HTTP-message = start-line *( header-field CRLF ) CRLF [ message-body
] ]
HTTP-name = %x48.54.54.50 ; HTTP HTTP-name = %x48.54.54.50 ; HTTP
HTTP-version = HTTP-name "/" DIGIT "." DIGIT HTTP-version = HTTP-name "/" DIGIT "." DIGIT
Host = uri-host [ ":" port ] Host = uri-host [ ":" port ]
OWS = *( SP / HTAB ) OWS = *( SP / HTAB )
skipping to change at page 74, line 4 skipping to change at page 75, line 48
HTTP-message = start-line *( header-field CRLF ) CRLF [ message-body HTTP-message = start-line *( header-field CRLF ) CRLF [ message-body
] ]
HTTP-name = %x48.54.54.50 ; HTTP HTTP-name = %x48.54.54.50 ; HTTP
HTTP-version = HTTP-name "/" DIGIT "." DIGIT HTTP-version = HTTP-name "/" DIGIT "." DIGIT
Host = uri-host [ ":" port ] Host = uri-host [ ":" port ]
OWS = *( SP / HTAB ) OWS = *( SP / HTAB )
RWS = 1*( SP / HTAB ) RWS = 1*( SP / HTAB )
TE = [ ( "," / t-codings ) *( OWS "," [ OWS t-codings ] ) ] TE = [ ( "," / t-codings ) *( OWS "," [ OWS t-codings ] ) ]
Trailer = *( "," OWS ) field-name *( OWS "," [ OWS field-name ] ) Trailer = *( "," OWS ) field-name *( OWS "," [ OWS field-name ] )
Transfer-Encoding = *( "," OWS ) transfer-coding *( OWS "," [ OWS Transfer-Encoding = *( "," OWS ) transfer-coding *( OWS "," [ OWS
transfer-coding ] ) transfer-coding ] )
URI-reference = <URI-reference, defined in [RFC3986], Section 4.1> URI-reference = <URI-reference, defined in [RFC3986], Section 4.1>
Upgrade = *( "," OWS ) protocol *( OWS "," [ OWS protocol ] ) Upgrade = *( "," OWS ) protocol *( OWS "," [ OWS protocol ] )
Via = *( "," OWS ) received-protocol RWS received-by [ RWS comment ] Via = *( "," OWS ) ( received-protocol RWS received-by [ RWS comment
*( OWS "," [ OWS received-protocol RWS received-by [ RWS comment ] ] ] ) *( OWS "," [ OWS ( received-protocol RWS received-by [ RWS
) comment ] ) ] )
absolute-URI = <absolute-URI, defined in [RFC3986], Section 4.3> absolute-URI = <absolute-URI, defined in [RFC3986], Section 4.3>
absolute-form = absolute-URI absolute-form = absolute-URI
asterisk-form = "*" asterisk-form = "*"
attribute = token attribute = token
authority = <authority, defined in [RFC3986], Section 3.2> authority = <authority, defined in [RFC3986], Section 3.2>
authority-form = authority authority-form = authority
chunk = chunk-size [ chunk-ext ] CRLF chunk-data CRLF chunk = chunk-size [ chunk-ext ] CRLF chunk-data CRLF
chunk-data = 1*OCTET chunk-data = 1*OCTET
chunk-ext = *( ";" chunk-ext-name [ "=" chunk-ext-val ] ) chunk-ext = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
chunk-ext-name = token chunk-ext-name = token
chunk-ext-val = token / quoted-str-nf chunk-ext-val = token / quoted-str-nf
chunk-size = 1*HEXDIG chunk-size = 1*HEXDIG
chunked-body = *chunk last-chunk trailer-part CRLF chunked-body = *chunk last-chunk trailer-part CRLF
comment = "(" *( ctext / quoted-cpair / comment ) ")" comment = "(" *( ctext / quoted-cpair / comment ) ")"
connection-token = token connection-option = token
ctext = OWS / %x21-27 ; '!'-''' ctext = OWS / %x21-27 ; '!'-'''
/ %x2A-5B ; '*'-'[' / %x2A-5B ; '*'-'['
/ %x5D-7E ; ']'-'~' / %x5D-7E ; ']'-'~'
/ obs-text / obs-text
field-content = *( HTAB / SP / VCHAR / obs-text ) field-content = *( HTAB / SP / VCHAR / obs-text )
field-name = token field-name = token
field-value = *( field-content / obs-fold ) field-value = *( field-content / obs-fold )
header-field = field-name ":" OWS field-value BWS header-field = field-name ":" OWS field-value BWS
skipping to change at page 76, line 5 skipping to change at page 78, line 4
tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." / tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." /
"^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA
te-ext = OWS ";" OWS token [ "=" word ] te-ext = OWS ";" OWS token [ "=" word ]
te-params = OWS ";" OWS "q=" qvalue *te-ext te-params = OWS ";" OWS "q=" qvalue *te-ext
token = 1*tchar token = 1*tchar
trailer-part = *( header-field CRLF ) trailer-part = *( header-field CRLF )
transfer-coding = "chunked" / "compress" / "deflate" / "gzip" / transfer-coding = "chunked" / "compress" / "deflate" / "gzip" /
transfer-extension transfer-extension
transfer-extension = token *( OWS ";" OWS transfer-parameter ) transfer-extension = token *( OWS ";" OWS transfer-parameter )
transfer-parameter = attribute BWS "=" BWS value transfer-parameter = attribute BWS "=" BWS value
uri-host = <host, defined in [RFC3986], Section 3.2.2> uri-host = <host, defined in [RFC3986], Section 3.2.2>
value = word value = word
word = token / quoted-string word = token / quoted-string
ABNF diagnostics: Appendix D. Change Log (to be removed by RFC Editor before publication)
; Connection defined but not used
; Content-Length defined but not used
; HTTP-message defined but not used
; Host defined but not used
; TE defined but not used
; Trailer defined but not used
; Transfer-Encoding defined but not used
; URI-reference defined but not used
; Upgrade defined but not used
; Via defined but not used
; chunked-body defined but not used
; http-URI defined but not used
; https-URI defined but not used
; partial-URI defined but not used
; special defined but not used
Appendix C. Change Log (to be removed by RFC Editor before publication)
C.1. Since RFC 2616 D.1. Since RFC 2616
Extracted relevant partitions from [RFC2616]. Extracted relevant partitions from [RFC2616].
C.2. Since draft-ietf-httpbis-p1-messaging-00 D.2. Since draft-ietf-httpbis-p1-messaging-00
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/1>: "HTTP Version o <http://tools.ietf.org/wg/httpbis/trac/ticket/1>: "HTTP Version
should be case sensitive" should be case sensitive"
(<http://purl.org/NET/http-errata#verscase>) (<http://purl.org/NET/http-errata#verscase>)
o <http://tools.ietf.org/wg/httpbis/trac/ticket/2>: "'unsafe' o <http://tools.ietf.org/wg/httpbis/trac/ticket/2>: "'unsafe'
characters" (<http://purl.org/NET/http-errata#unsafe-uri>) characters" (<http://purl.org/NET/http-errata#unsafe-uri>)
skipping to change at page 78, line 11 skipping to change at page 79, line 39
to-date references" to-date references"
Other changes: Other changes:
o Update media type registrations to use RFC4288 template. o Update media type registrations to use RFC4288 template.
o Use names of RFC4234 core rules DQUOTE and HTAB, fix broken ABNF o Use names of RFC4234 core rules DQUOTE and HTAB, fix broken ABNF
for chunk-data (work in progress on for chunk-data (work in progress on
<http://tools.ietf.org/wg/httpbis/trac/ticket/36>) <http://tools.ietf.org/wg/httpbis/trac/ticket/36>)
C.3. Since draft-ietf-httpbis-p1-messaging-01 D.3. Since draft-ietf-httpbis-p1-messaging-01
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/19>: "Bodies on GET o <http://tools.ietf.org/wg/httpbis/trac/ticket/19>: "Bodies on GET
(and other) requests" (and other) requests"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/55>: "Updating to o <http://tools.ietf.org/wg/httpbis/trac/ticket/55>: "Updating to
RFC4288" RFC4288"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/57>: "Status Code o <http://tools.ietf.org/wg/httpbis/trac/ticket/57>: "Status Code
skipping to change at page 79, line 8 skipping to change at page 80, line 37
o Move "Product Tokens" section (back) into Part 1, as "token" is o Move "Product Tokens" section (back) into Part 1, as "token" is
used in the definition of the Upgrade header field. used in the definition of the Upgrade header field.
o Add explicit references to BNF syntax and rules imported from o Add explicit references to BNF syntax and rules imported from
other parts of the specification. other parts of the specification.
o Rewrite prose rule "token" in terms of "tchar", rewrite prose rule o Rewrite prose rule "token" in terms of "tchar", rewrite prose rule
"TEXT". "TEXT".
C.4. Since draft-ietf-httpbis-p1-messaging-02 D.4. Since draft-ietf-httpbis-p1-messaging-02
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/51>: "HTTP-date vs. o <http://tools.ietf.org/wg/httpbis/trac/ticket/51>: "HTTP-date vs.
rfc1123-date" rfc1123-date"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/64>: "WS in quoted- o <http://tools.ietf.org/wg/httpbis/trac/ticket/64>: "WS in quoted-
pair" pair"
Ongoing work on IANA Message Header Field Registration Ongoing work on IANA Message Header Field Registration
(<http://tools.ietf.org/wg/httpbis/trac/ticket/40>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/40>):
o Reference RFC 3984, and update header field registrations for o Reference RFC 3984, and update header field registrations for
headers defined in this document. header fields defined in this document.
Ongoing work on ABNF conversion Ongoing work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Replace string literals when the string really is case-sensitive o Replace string literals when the string really is case-sensitive
(HTTP-version). (HTTP-version).
C.5. Since draft-ietf-httpbis-p1-messaging-03 D.5. Since draft-ietf-httpbis-p1-messaging-03
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/28>: "Connection o <http://tools.ietf.org/wg/httpbis/trac/ticket/28>: "Connection
closing" closing"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/97>: "Move o <http://tools.ietf.org/wg/httpbis/trac/ticket/97>: "Move
registrations and registry information to IANA Considerations" registrations and registry information to IANA Considerations"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/120>: "need new URL o <http://tools.ietf.org/wg/httpbis/trac/ticket/120>: "need new URL
for PAD1995 reference" for PAD1995 reference"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/127>: "IANA o <http://tools.ietf.org/wg/httpbis/trac/ticket/127>: "IANA
Considerations: update HTTP URI scheme registration" Considerations: update HTTP URI scheme registration"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/128>: "Cite HTTPS o <http://tools.ietf.org/wg/httpbis/trac/ticket/128>: "Cite HTTPS
URI scheme definition" URI scheme definition"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/129>: "List-type o <http://tools.ietf.org/wg/httpbis/trac/ticket/129>: "List-type
headers vs Set-Cookie" header fields vs Set-Cookie"
Ongoing work on ABNF conversion Ongoing work on ABNF conversion
(<http://tools.ietf.org/wg/httpbis/trac/ticket/36>): (<http://tools.ietf.org/wg/httpbis/trac/ticket/36>):
o Replace string literals when the string really is case-sensitive o Replace string literals when the string really is case-sensitive
(HTTP-Date). (HTTP-Date).
o Replace HEX by HEXDIG for future consistence with RFC 5234's core o Replace HEX by HEXDIG for future consistence with RFC 5234's core
rules. rules.
C.6. Since draft-ietf-httpbis-p1-messaging-04 D.6. Since draft-ietf-httpbis-p1-messaging-04
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/34>: "Out-of-date o <http://tools.ietf.org/wg/httpbis/trac/ticket/34>: "Out-of-date
reference for URIs" reference for URIs"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/132>: "RFC 2822 is o <http://tools.ietf.org/wg/httpbis/trac/ticket/132>: "RFC 2822 is
updated by RFC 5322" updated by RFC 5322"
Ongoing work on ABNF conversion Ongoing work on ABNF conversion
skipping to change at page 80, line 37 skipping to change at page 82, line 18
o Get rid of RFC822 dependency; use RFC5234 plus extensions instead. o Get rid of RFC822 dependency; use RFC5234 plus extensions instead.
o Only reference RFC 5234's core rules. o Only reference RFC 5234's core rules.
o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional o Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
whitespace ("OWS") and required whitespace ("RWS"). whitespace ("OWS") and required whitespace ("RWS").
o Rewrite ABNFs to spell out whitespace rules, factor out header o Rewrite ABNFs to spell out whitespace rules, factor out header
field value format definitions. field value format definitions.
C.7. Since draft-ietf-httpbis-p1-messaging-05 D.7. Since draft-ietf-httpbis-p1-messaging-05
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/30>: "Header LWS" o <http://tools.ietf.org/wg/httpbis/trac/ticket/30>: "Header LWS"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/52>: "Sort 1.3 o <http://tools.ietf.org/wg/httpbis/trac/ticket/52>: "Sort 1.3
Terminology" Terminology"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/63>: "RFC2047 o <http://tools.ietf.org/wg/httpbis/trac/ticket/63>: "RFC2047
encoded words" encoded words"
skipping to change at page 81, line 36 skipping to change at page 83, line 17
o Add appendix containing collected and expanded ABNF. o Add appendix containing collected and expanded ABNF.
Other changes: Other changes:
o Rewrite introduction; add mostly new Architecture Section. o Rewrite introduction; add mostly new Architecture Section.
o Move definition of quality values from Part 3 into Part 1; make TE o Move definition of quality values from Part 3 into Part 1; make TE
request header field grammar independent of accept-params (defined request header field grammar independent of accept-params (defined
in Part 3). in Part 3).
C.8. Since draft-ietf-httpbis-p1-messaging-06 D.8. Since draft-ietf-httpbis-p1-messaging-06
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/161>: "base for o <http://tools.ietf.org/wg/httpbis/trac/ticket/161>: "base for
numeric protocol elements" numeric protocol elements"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/162>: "comment ABNF" o <http://tools.ietf.org/wg/httpbis/trac/ticket/162>: "comment ABNF"
Partly resolved issues: Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/88>: "205 Bodies" o <http://tools.ietf.org/wg/httpbis/trac/ticket/88>: "205 Bodies"
(took out language that implied that there might be methods for (took out language that implied that there might be methods for
which a request body MUST NOT be included) which a request body MUST NOT be included)
o <http://tools.ietf.org/wg/httpbis/trac/ticket/163>: "editorial o <http://tools.ietf.org/wg/httpbis/trac/ticket/163>: "editorial
improvements around HTTP-date" improvements around HTTP-date"
C.9. Since draft-ietf-httpbis-p1-messaging-07 D.9. Since draft-ietf-httpbis-p1-messaging-07
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/93>: "Repeating o <http://tools.ietf.org/wg/httpbis/trac/ticket/93>: "Repeating
single-value headers" single-value header fields"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/131>: "increase o <http://tools.ietf.org/wg/httpbis/trac/ticket/131>: "increase
connection limit" connection limit"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/157>: "IP addresses o <http://tools.ietf.org/wg/httpbis/trac/ticket/157>: "IP addresses
in URLs" in URLs"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/172>: "take over o <http://tools.ietf.org/wg/httpbis/trac/ticket/172>: "take over
HTTP Upgrade Token Registry" HTTP Upgrade Token Registry"
skipping to change at page 82, line 42 skipping to change at page 84, line 23
o <http://tools.ietf.org/wg/httpbis/trac/ticket/194>: "disallow o <http://tools.ietf.org/wg/httpbis/trac/ticket/194>: "disallow
control characters in quoted-pair" control characters in quoted-pair"
Partly resolved issues: Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/148>: "update IANA o <http://tools.ietf.org/wg/httpbis/trac/ticket/148>: "update IANA
requirements wrt Transfer-Coding values" (add the IANA requirements wrt Transfer-Coding values" (add the IANA
Considerations subsection) Considerations subsection)
C.10. Since draft-ietf-httpbis-p1-messaging-08 D.10. Since draft-ietf-httpbis-p1-messaging-08
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/201>: "header o <http://tools.ietf.org/wg/httpbis/trac/ticket/201>: "header
parsing, treatment of leading and trailing OWS" parsing, treatment of leading and trailing OWS"
Partly resolved issues: Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/60>: "Placement of o <http://tools.ietf.org/wg/httpbis/trac/ticket/60>: "Placement of
13.5.1 and 13.5.2" 13.5.1 and 13.5.2"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/200>: "use of term o <http://tools.ietf.org/wg/httpbis/trac/ticket/200>: "use of term
"word" when talking about header structure" "word" when talking about header field structure"
C.11. Since draft-ietf-httpbis-p1-messaging-09 D.11. Since draft-ietf-httpbis-p1-messaging-09
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/73>: "Clarification o <http://tools.ietf.org/wg/httpbis/trac/ticket/73>: "Clarification
of the term 'deflate'" of the term 'deflate'"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/83>: "OPTIONS * and o <http://tools.ietf.org/wg/httpbis/trac/ticket/83>: "OPTIONS * and
proxies" proxies"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/122>: "MIME-Version o <http://tools.ietf.org/wg/httpbis/trac/ticket/122>: "MIME-Version
not listed in P1, general header fields" not listed in P1, general header fields"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/143>: "IANA registry o <http://tools.ietf.org/wg/httpbis/trac/ticket/143>: "IANA registry
for content/transfer encodings" for content/transfer encodings"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/165>: "Case- o <http://tools.ietf.org/wg/httpbis/trac/ticket/165>: "Case-
sensitivity of HTTP-date" sensitivity of HTTP-date"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/200>: "use of term o <http://tools.ietf.org/wg/httpbis/trac/ticket/200>: "use of term
"word" when talking about header structure" "word" when talking about header field structure"
Partly resolved issues: Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/196>: "Term for the o <http://tools.ietf.org/wg/httpbis/trac/ticket/196>: "Term for the
requested resource's URI" requested resource's URI"
C.12. Since draft-ietf-httpbis-p1-messaging-10 D.12. Since draft-ietf-httpbis-p1-messaging-10
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/28>: "Connection o <http://tools.ietf.org/wg/httpbis/trac/ticket/28>: "Connection
Closing" Closing"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/90>: "Delimiting o <http://tools.ietf.org/wg/httpbis/trac/ticket/90>: "Delimiting
messages with multipart/byteranges" messages with multipart/byteranges"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/95>: "Handling o <http://tools.ietf.org/wg/httpbis/trac/ticket/95>: "Handling
multiple Content-Length headers" multiple Content-Length header fields"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/109>: "Clarify o <http://tools.ietf.org/wg/httpbis/trac/ticket/109>: "Clarify
entity / representation / variant terminology" entity / representation / variant terminology"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/220>: "consider o <http://tools.ietf.org/wg/httpbis/trac/ticket/220>: "consider
removing the 'changes from 2068' sections" removing the 'changes from 2068' sections"
Partly resolved issues: Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/159>: "HTTP(s) URI o <http://tools.ietf.org/wg/httpbis/trac/ticket/159>: "HTTP(s) URI
scheme definitions" scheme definitions"
C.13. Since draft-ietf-httpbis-p1-messaging-11 D.13. Since draft-ietf-httpbis-p1-messaging-11
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/193>: "Trailer o <http://tools.ietf.org/wg/httpbis/trac/ticket/193>: "Trailer
requirements" requirements"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/204>: "Text about o <http://tools.ietf.org/wg/httpbis/trac/ticket/204>: "Text about
clock requirement for caches belongs in p6" clock requirement for caches belongs in p6"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/221>: "effective o <http://tools.ietf.org/wg/httpbis/trac/ticket/221>: "effective
request URI: handling of missing host in HTTP/1.0" request URI: handling of missing host in HTTP/1.0"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/248>: "confusing o <http://tools.ietf.org/wg/httpbis/trac/ticket/248>: "confusing
Date requirements for clients" Date requirements for clients"
Partly resolved issues: Partly resolved issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/95>: "Handling o <http://tools.ietf.org/wg/httpbis/trac/ticket/95>: "Handling
multiple Content-Length headers" multiple Content-Length header fields"
C.14. Since draft-ietf-httpbis-p1-messaging-12 D.14. Since draft-ietf-httpbis-p1-messaging-12
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/75>: "RFC2145 o <http://tools.ietf.org/wg/httpbis/trac/ticket/75>: "RFC2145
Normative" Normative"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/159>: "HTTP(s) URI o <http://tools.ietf.org/wg/httpbis/trac/ticket/159>: "HTTP(s) URI
scheme definitions" (tune the requirements on userinfo) scheme definitions" (tune the requirements on userinfo)
o <http://tools.ietf.org/wg/httpbis/trac/ticket/210>: "define o <http://tools.ietf.org/wg/httpbis/trac/ticket/210>: "define
'transparent' proxy" 'transparent' proxy"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/224>: "Header o <http://tools.ietf.org/wg/httpbis/trac/ticket/224>: "Header Field
Classification" Classification"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/233>: "Is * usable o <http://tools.ietf.org/wg/httpbis/trac/ticket/233>: "Is * usable
as a request-uri for new methods?" as a request-uri for new methods?"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/240>: "Migrate o <http://tools.ietf.org/wg/httpbis/trac/ticket/240>: "Migrate
Upgrade details from RFC2817" Upgrade details from RFC2817"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/276>: "untangle o <http://tools.ietf.org/wg/httpbis/trac/ticket/276>: "untangle
ABNFs for header fields" ABNFs for header fields"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/279>: "update RFC o <http://tools.ietf.org/wg/httpbis/trac/ticket/279>: "update RFC
2109 reference" 2109 reference"
C.15. Since draft-ietf-httpbis-p1-messaging-13 D.15. Since draft-ietf-httpbis-p1-messaging-13
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/53>: "Allow is not o <http://tools.ietf.org/wg/httpbis/trac/ticket/53>: "Allow is not
in 13.5.2" in 13.5.2"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/95>: "Handling o <http://tools.ietf.org/wg/httpbis/trac/ticket/95>: "Handling
multiple Content-Length headers" multiple Content-Length header fields"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/276>: "untangle o <http://tools.ietf.org/wg/httpbis/trac/ticket/276>: "untangle
ABNFs for header fields" ABNFs for header fields"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/286>: "Content- o <http://tools.ietf.org/wg/httpbis/trac/ticket/286>: "Content-
Length ABNF broken" Length ABNF broken"
C.16. Since draft-ietf-httpbis-p1-messaging-14 D.16. Since draft-ietf-httpbis-p1-messaging-14
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/273>: "HTTP-version o <http://tools.ietf.org/wg/httpbis/trac/ticket/273>: "HTTP-version
should be redefined as fixed length pair of DIGIT . DIGIT" should be redefined as fixed length pair of DIGIT . DIGIT"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/282>: "Recommend o <http://tools.ietf.org/wg/httpbis/trac/ticket/282>: "Recommend
minimum sizes for protocol elements" minimum sizes for protocol elements"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/283>: "Set o <http://tools.ietf.org/wg/httpbis/trac/ticket/283>: "Set
expectations around buffering" expectations around buffering"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/288>: "Considering o <http://tools.ietf.org/wg/httpbis/trac/ticket/288>: "Considering
messages in isolation" messages in isolation"
C.17. Since draft-ietf-httpbis-p1-messaging-15 D.17. Since draft-ietf-httpbis-p1-messaging-15
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/100>: "DNS Spoofing o <http://tools.ietf.org/wg/httpbis/trac/ticket/100>: "DNS Spoofing
/ DNS Binding advice" / DNS Binding advice"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/254>: "move RFCs o <http://tools.ietf.org/wg/httpbis/trac/ticket/254>: "move RFCs
2145, 2616, 2817 to Historic status" 2145, 2616, 2817 to Historic status"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/270>: "\-escaping in o <http://tools.ietf.org/wg/httpbis/trac/ticket/270>: "\-escaping in
quoted strings" quoted strings"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/305>: "'Close' o <http://tools.ietf.org/wg/httpbis/trac/ticket/305>: "'Close'
should be reserved in the HTTP header field registry" should be reserved in the HTTP header field registry"
C.18. Since draft-ietf-httpbis-p1-messaging-16 D.18. Since draft-ietf-httpbis-p1-messaging-16
Closed issues: Closed issues:
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"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/215>: "Explain o <http://tools.ietf.org/wg/httpbis/trac/ticket/215>: "Explain
header registration" header field registration"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/219>: "Revise o <http://tools.ietf.org/wg/httpbis/trac/ticket/219>: "Revise
Acknowledgements Sections" Acknowledgements Sections"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/297>: "Retrying o <http://tools.ietf.org/wg/httpbis/trac/ticket/297>: "Retrying
Requests" Requests"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/318>: "Closing the o <http://tools.ietf.org/wg/httpbis/trac/ticket/318>: "Closing the
connection on server error" connection on server error"
C.19. Since draft-ietf-httpbis-p1-messaging-17 D.19. Since draft-ietf-httpbis-p1-messaging-17
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/158>: "Proxy-
Connection and Keep-Alive"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/166>: "Clarify 'User o <http://tools.ietf.org/wg/httpbis/trac/ticket/166>: "Clarify 'User
Agent'" Agent'"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/300>: "Define non- o <http://tools.ietf.org/wg/httpbis/trac/ticket/300>: "Define non-
final responses" final responses"
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"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/324>: "Intermediary o <http://tools.ietf.org/wg/httpbis/trac/ticket/324>: "Intermediary
rewriting of queries" rewriting of queries"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/158>: "Proxy- D.20. Since draft-ietf-httpbis-p1-messaging-18
Connection and Keep-Alive"
C.20. Since draft-ietf-httpbis-p1-messaging-18
Closed issues: Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/250>: "message-body o <http://tools.ietf.org/wg/httpbis/trac/ticket/250>: "message-body
in CONNECT response" in CONNECT response"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/302>: "Misplaced o <http://tools.ietf.org/wg/httpbis/trac/ticket/302>: "Misplaced
text on connection handling in p2" text on connection handling in p2"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/335>: "wording of o <http://tools.ietf.org/wg/httpbis/trac/ticket/335>: "wording of
line folding rule" line folding rule"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/343>: "chunk- o <http://tools.ietf.org/wg/httpbis/trac/ticket/343>: "chunk-
extensions" extensions"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/346>: "make IANA o <http://tools.ietf.org/wg/httpbis/trac/ticket/346>: "make IANA
policy definitions consistent" policy definitions consistent"
D.21. Since draft-ietf-httpbis-p1-messaging-19
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/346>: "make IANA
policy definitions consistent"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/359>: "clarify
connection header field values are case-insensitive"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/361>: "ABNF
requirements for recipients"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/368>: "note
introduction of new IANA registries as normative changes"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/374>: "Reference to
ISO-8859-1 is informative"
Index Index
A A
absolute-form (of request-target) 41 absolute-form (of request-target) 41
accelerator 11 accelerator 11
application/http Media Type 60 application/http Media Type 60
asterisk-form (of request-target) 41 asterisk-form (of request-target) 41
authority-form (of request-target) 41 authority-form (of request-target) 41
B B
browser 7 browser 8
C C
cache 12 cache 13
cacheable 12 cacheable 13
captive portal 11 captive portal 12
chunked (Coding Format) 34 chunked (Coding Format) 34
client 7 client 7
Coding Format Coding Format
chunked 34 chunked 34
compress 36 compress 36
deflate 36 deflate 36
gzip 36 gzip 36
compress (Coding Format) 36 compress (Coding Format) 36
connection 7 connection 7
Connection header field 47 Connection header field 47
Content-Length header field 29 Content-Length header field 29
D D
deflate (Coding Format) 36 deflate (Coding Format) 36
downstream 10 downstream 11
E E
effective request URI 43 effective request URI 43
G G
gateway 11 gateway 11
Grammar Grammar
absolute-form 40 absolute-form 40
absolute-URI 16 absolute-URI 17
ALPHA 7 ALPHA 7
asterisk-form 40 asterisk-form 40
attribute 34 attribute 34
authority 16 authority 17
authority-form 40 authority-form 40
BWS 23 BWS 24
chunk 34 chunk 34
chunk-data 34 chunk-data 34
chunk-ext 34 chunk-ext 34
chunk-ext-name 34 chunk-ext-name 34
chunk-ext-val 34 chunk-ext-val 34
chunk-size 34 chunk-size 34
chunked-body 34 chunked-body 34
comment 25 comment 27
Connection 47 Connection 47
connection-token 47 connection-option 47
Content-Length 29 Content-Length 29
CR 7 CR 7
CRLF 7 CRLF 7
ctext 25 ctext 27
CTL 7 CTL 7
date2 34 date2 34
date3 34 date3 34
DIGIT 7 DIGIT 7
DQUOTE 7 DQUOTE 7
field-content 22 field-content 23
field-name 22 field-name 23
field-value 22 field-value 23
header-field 22 header-field 23
HEXDIG 7 HEXDIG 7
Host 42 Host 42
HTAB 7 HTAB 7
HTTP-message 19 HTTP-message 20
HTTP-name 13 HTTP-name 14
http-URI 16 http-URI 17
HTTP-version 13 HTTP-version 14
https-URI 18 https-URI 19
last-chunk 34 last-chunk 34
LF 7 LF 7
message-body 27 message-body 27
method 20 method 21
obs-fold 22 obs-fold 23
obs-text 25 obs-text 26
OCTET 7 OCTET 7
origin-form 40 origin-form 40
OWS 23 OWS 24
path-absolute 16 partial-URI 17
port 16 path-absolute 17
port 17
protocol-name 49 protocol-name 49
protocol-version 49 protocol-version 49
pseudonym 49 pseudonym 49
qdtext 25 qdtext 26
qdtext-nf 34 qdtext-nf 34
query 16 query 17
quoted-cpair 26 quoted-cpair 27
quoted-pair 25 quoted-pair 26
quoted-str-nf 34 quoted-str-nf 34
quoted-string 25 quoted-string 26
qvalue 38 qvalue 38
reason-phrase 21 reason-phrase 22
received-by 49 received-by 49
received-protocol 49 received-protocol 49
request-line 20 request-line 21
request-target 40 request-target 40
RWS 23 RWS 24
SP 7 SP 7
special 25 special 26
start-line 20 start-line 21
status-code 21 status-code 22
status-line 21 status-line 22
t-codings 37 t-codings 37
tchar 25 tchar 26
TE 37 TE 37
te-ext 37 te-ext 37
te-params 37 te-params 37
token 25 token 26
Trailer 38 Trailer 38
trailer-part 34 trailer-part 34
transfer-coding 34 transfer-coding 34
Transfer-Encoding 28 Transfer-Encoding 28
transfer-extension 34 transfer-extension 34
transfer-parameter 34 transfer-parameter 34
Upgrade 56 Upgrade 57
uri-host 16 uri-host 17
URI-reference 16 URI-reference 17
value 34 value 34
VCHAR 7 VCHAR 7
Via 49 Via 49
word 25 word 26
gzip (Coding Format) 36 gzip (Coding Format) 36
H H
header field 19 header field 20
Header Fields Header Fields
Connection 47 Connection 47
Content-Length 29 Content-Length 29
Host 42 Host 42
TE 36 TE 36
Trailer 38 Trailer 38
Transfer-Encoding 27 Transfer-Encoding 27
Upgrade 56 Upgrade 56
Via 49 Via 49
header section 19 header section 20
headers 19 headers 20
Host header field 42 Host header field 42
http URI scheme 16 http URI scheme 17
https URI scheme 17 https URI scheme 18
I I
inbound 10 inbound 11
interception proxy 11 interception proxy 12
intermediary 9 intermediary 10
M M
Media Type Media Type
application/http 60 application/http 60
message/http 59 message/http 59
message 8 message 8
message/http Media Type 59 message/http Media Type 59
method 20 method 21
N N
non-transforming proxy 10 non-transforming proxy 11
O O
origin server 7 origin server 8
origin-form (of request-target) 40 origin-form (of request-target) 40
outbound 10 outbound 11
P P
proxy 10 proxy 11
R R
recipient 7 recipient 8
request 8 request 8
request-target 20 request-target 21
resource 15 resource 16
response 8 response 8
reverse proxy 11 reverse proxy 11
S S
sender 7 sender 8
server 7 server 7
spider 7 spider 8
T T
target resource 39 target resource 39
target URI 39 target URI 39
TE header field 36 TE header field 36
Trailer header field 38 Trailer header field 38
Transfer-Encoding header field 27 Transfer-Encoding header field 27
transforming proxy 10 transforming proxy 11
transparent proxy 11 transparent proxy 12
tunnel 11 tunnel 12
U U
Upgrade header field 56 Upgrade header field 56
upstream 10 upstream 11
URI scheme URI scheme
http 16 http 17
https 17 https 18
user agent 7 user agent 8
V V
Via header field 49 Via header field 49
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
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EMail: ylafon@w3.org EMail: ylafon@w3.org
URI: http://www.raubacapeu.net/people/yves/ URI: http://www.raubacapeu.net/people/yves/
Julian F. Reschke (editor) Julian F. Reschke (editor)
greenbytes GmbH greenbytes GmbH
Hafenweg 16 Hafenweg 16
Muenster, NW 48155 Muenster, NW 48155
Germany Germany
Phone: +49 251 2807760
Fax: +49 251 2807761
EMail: julian.reschke@greenbytes.de EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/ URI: http://greenbytes.de/tech/webdav/
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