| draft-ietf-httpbis-p1-messaging-20.txt |  | draft-ietf-httpbis-p1-messaging-21.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) J. Reschke, Ed. |
| Updates: 2817 (if approved) W3C |  | Updates: 2817 (if approved) greenbytes |
| Intended status: Standards Track J. Reschke, Ed. |  | Intended status: Standards Track October 4, 2012 |
| Expires: January 17, 2013 greenbytes |  | Expires: April 7, 2013 |
| July 16, 2012 |  |  |
| HTTP/1.1, part 1: Message Routing and Syntax" |  | Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing |
| draft-ietf-httpbis-p1-messaging-20 |  | draft-ietf-httpbis-p1-messaging-21 |
| 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 provides an |  | information initiative since 1990. This document provides an |
| overview of HTTP architecture and its associated terminology, defines |  | overview of HTTP architecture and its associated terminology, defines |
| the "http" and "https" Uniform Resource Identifier (URI) schemes, |  | the "http" and "https" Uniform Resource Identifier (URI) schemes, |
| defines the HTTP/1.1 message syntax and parsing requirements, and |  | defines the HTTP/1.1 message syntax and parsing requirements, and |
| skipping to change at page 1, line 36 |  | skipping to change at page 1, line 35 |
| Discussion of this draft takes place on the HTTPBIS working group |  | Discussion of this draft takes place on the HTTPBIS working 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 D.21. |  | The changes in this draft are summarized in Appendix D.22. |
| 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 January 17, 2013. |  | This Internet-Draft will expire on April 7, 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 2, line 38 |  | skipping to change at page 2, line 37 |
| modifications of such material outside the IETF Standards Process. |  | modifications of such material outside the IETF Standards Process. |
| Without obtaining an adequate license from the person(s) controlling |  | Without obtaining an adequate license from the person(s) controlling |
| the copyright in such materials, this document may not be modified |  | the copyright in such materials, this document may not be modified |
| outside the IETF Standards Process, and derivative works of it may |  | outside the IETF Standards Process, and derivative works of it may |
| not be created outside the IETF Standards Process, except to format |  | not be created outside the IETF Standards Process, except to format |
| 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 . . . . . . . . . . . . . . . . . . . . . . . . . 5 |
| 1.1. Requirement Notation . . . . . . . . . . . . . . . . . . . 7 |  | 1.1. Requirement Notation . . . . . . . . . . . . . . . . . . . 6 |
| 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 7 |  | 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 6 |
| 2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 7 |  | 2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 6 |
| 2.1. Client/Server Messaging . . . . . . . . . . . . . . . . . 7 |  | 2.1. Client/Server Messaging . . . . . . . . . . . . . . . . . 7 |
| 2.2. Implementation Diversity . . . . . . . . . . . . . . . . . 9 |  | 2.2. Implementation Diversity . . . . . . . . . . . . . . . . . 8 |
| 2.3. Connections and Transport Independence . . . . . . . . . . 10 |  | 2.3. Intermediaries . . . . . . . . . . . . . . . . . . . . . . 9 |
| 2.4. Intermediaries . . . . . . . . . . . . . . . . . . . . . . 10 |  | 2.4. Caches . . . . . . . . . . . . . . . . . . . . . . . . . . 11 |
| 2.5. Caches . . . . . . . . . . . . . . . . . . . . . . . . . . 13 |  | 2.5. Conformance and Error Handling . . . . . . . . . . . . . . 12 |
| 2.6. Conformance and Error Handling . . . . . . . . . . . . . . 13 |  | 2.6. Protocol Versioning . . . . . . . . . . . . . . . . . . . 13 |
| 2.7. Protocol Versioning . . . . . . . . . . . . . . . . . . . 14 |  | 2.7. Uniform Resource Identifiers . . . . . . . . . . . . . . . 15 |
| 2.8. Uniform Resource Identifiers . . . . . . . . . . . . . . . 16 |  | 2.7.1. http URI scheme . . . . . . . . . . . . . . . . . . . 16 |
| 2.8.1. http URI scheme . . . . . . . . . . . . . . . . . . . 17 |  | 2.7.2. https URI scheme . . . . . . . . . . . . . . . . . . . 17 |
| 2.8.2. https URI scheme . . . . . . . . . . . . . . . . . . . 18 |  | 2.7.3. http and https URI Normalization and Comparison . . . 18 |
| 2.8.3. http and https URI Normalization and Comparison . . . 19 |  | 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 18 |
| 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 20 |  | 3.1. Start Line . . . . . . . . . . . . . . . . . . . . . . . . 19 |
| 3.1. Start Line . . . . . . . . . . . . . . . . . . . . . . . . 20 |  | 3.1.1. Request Line . . . . . . . . . . . . . . . . . . . . . 20 |
| 3.1.1. Request Line . . . . . . . . . . . . . . . . . . . . . 21 |  | 3.1.2. Status Line . . . . . . . . . . . . . . . . . . . . . 21 |
| 3.1.2. Status Line . . . . . . . . . . . . . . . . . . . . . 22 |  | 3.2. Header Fields . . . . . . . . . . . . . . . . . . . . . . 21 |
| 3.2. Header Fields . . . . . . . . . . . . . . . . . . . . . . 23 |  | 3.2.1. Whitespace . . . . . . . . . . . . . . . . . . . . . . 23 |
| 3.2.1. Whitespace . . . . . . . . . . . . . . . . . . . . . . 24 |  | 3.2.2. Field Parsing . . . . . . . . . . . . . . . . . . . . 23 |
| 3.2.2. Field Parsing . . . . . . . . . . . . . . . . . . . . 25 |  | 3.2.3. Field Length . . . . . . . . . . . . . . . . . . . . . 24 |
| 3.2.3. Field Length . . . . . . . . . . . . . . . . . . . . . 25 |  | 3.2.4. Field value components . . . . . . . . . . . . . . . . 24 |
| 3.2.4. Field value components . . . . . . . . . . . . . . . . 26 |  | 3.3. Message Body . . . . . . . . . . . . . . . . . . . . . . . 26 |
| 3.3. Message Body . . . . . . . . . . . . . . . . . . . . . . . 27 |  | 3.3.1. Transfer-Encoding . . . . . . . . . . . . . . . . . . 26 |
| 3.3.1. Transfer-Encoding . . . . . . . . . . . . . . . . . . 27 |  | 3.3.2. Content-Length . . . . . . . . . . . . . . . . . . . . 28 |
| 3.3.2. Content-Length . . . . . . . . . . . . . . . . . . . . 29 |  | 3.3.3. Message Body Length . . . . . . . . . . . . . . . . . 29 |
| 3.3.3. Message Body Length . . . . . . . . . . . . . . . . . 30 |  | 3.4. Handling Incomplete Messages . . . . . . . . . . . . . . . 31 |
| 3.4. Handling Incomplete Messages . . . . . . . . . . . . . . . 32 |  | 3.5. Message Parsing Robustness . . . . . . . . . . . . . . . . 32 |
| 3.5. Message Parsing Robustness . . . . . . . . . . . . . . . . 33 |  | 4. Transfer Codings . . . . . . . . . . . . . . . . . . . . . . . 32 |
| 4. Transfer Codings . . . . . . . . . . . . . . . . . . . . . . . 33 |  | 4.1. Chunked Transfer Coding . . . . . . . . . . . . . . . . . 33 |
| 4.1. Chunked Transfer Coding . . . . . . . . . . . . . . . . . 34 |  | 4.1.1. Trailer . . . . . . . . . . . . . . . . . . . . . . . 34 |
| 4.2. Compression Codings . . . . . . . . . . . . . . . . . . . 36 |  | 4.1.2. Decoding chunked . . . . . . . . . . . . . . . . . . . 35 |
| 4.2.1. Compress Coding . . . . . . . . . . . . . . . . . . . 36 |  | 4.2. Compression Codings . . . . . . . . . . . . . . . . . . . 35 |
| 4.2.2. Deflate Coding . . . . . . . . . . . . . . . . . . . . 36 |  | 4.2.1. Compress Coding . . . . . . . . . . . . . . . . . . . 35 |
|  |  | 4.2.2. Deflate Coding . . . . . . . . . . . . . . . . . . . . 35 |
| 4.2.3. Gzip Coding . . . . . . . . . . . . . . . . . . . . . 36 |  | 4.2.3. Gzip Coding . . . . . . . . . . . . . . . . . . . . . 36 |
| 4.3. TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 |  | 4.3. TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 |
| 4.3.1. Quality Values . . . . . . . . . . . . . . . . . . . . 38 |  | 5. Message Routing . . . . . . . . . . . . . . . . . . . . . . . 37 |
| 4.4. Trailer . . . . . . . . . . . . . . . . . . . . . . . . . 38 |  | 5.1. Identifying a Target Resource . . . . . . . . . . . . . . 37 |
| 5. Message Routing . . . . . . . . . . . . . . . . . . . . . . . 39 |  | 5.2. Connecting Inbound . . . . . . . . . . . . . . . . . . . . 37 |
| 5.1. Identifying a Target Resource . . . . . . . . . . . . . . 39 |  | 5.3. Request Target . . . . . . . . . . . . . . . . . . . . . . 38 |
| 5.2. Connecting Inbound . . . . . . . . . . . . . . . . . . . . 39 |  | 5.4. Host . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 |
| 5.3. Request Target . . . . . . . . . . . . . . . . . . . . . . 40 |  | 5.5. Effective Request URI . . . . . . . . . . . . . . . . . . 41 |
| 5.4. Host . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 |  | 5.6. Message Forwarding . . . . . . . . . . . . . . . . . . . . 42 |
| 5.5. Effective Request URI . . . . . . . . . . . . . . . . . . 43 |  | 5.7. Via . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 |
| 5.6. Intermediary Forwarding . . . . . . . . . . . . . . . . . 44 |  | 5.8. Message Transforming . . . . . . . . . . . . . . . . . . . 44 |
| 5.6.1. End-to-end and Hop-by-hop Header Fields . . . . . . . 45 |  | 5.9. Associating a Response to a Request . . . . . . . . . . . 46 |
| 5.6.2. Non-modifiable Header Fields . . . . . . . . . . . . . 46 |  | 6. Connection Management . . . . . . . . . . . . . . . . . . . . 46 |
| 5.7. Associating a Response to a Request . . . . . . . . . . . 47 |  | 6.1. Connection . . . . . . . . . . . . . . . . . . . . . . . . 46 |
| 6. Connection Management . . . . . . . . . . . . . . . . . . . . 47 |  | 6.2. Persistent Connections . . . . . . . . . . . . . . . . . . 48 |
| 6.1. Connection . . . . . . . . . . . . . . . . . . . . . . . . 47 |  | 6.2.1. Establishment . . . . . . . . . . . . . . . . . . . . 49 |
| 6.2. Via . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 |  | 6.2.2. Reuse . . . . . . . . . . . . . . . . . . . . . . . . 50 |
| 6.3. Persistent Connections . . . . . . . . . . . . . . . . . . 50 |  | 6.2.3. Concurrency . . . . . . . . . . . . . . . . . . . . . 51 |
| 6.3.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . 50 |  | 6.2.4. Failures and Time-outs . . . . . . . . . . . . . . . . 51 |
| 6.3.2. Overall Operation . . . . . . . . . . . . . . . . . . 51 |  | 6.2.5. Tear-down . . . . . . . . . . . . . . . . . . . . . . 52 |
| 6.3.3. Practical Considerations . . . . . . . . . . . . . . . 53 |  | 6.3. Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 53 |
| 6.3.4. Retrying Requests . . . . . . . . . . . . . . . . . . 53 |  | 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 54 |
| 6.4. Message Transmission Requirements . . . . . . . . . . . . 54 |  | 7.1. Header Field Registration . . . . . . . . . . . . . . . . 54 |
| 6.4.1. Persistent Connections and Flow Control . . . . . . . 54 |  | 7.2. URI Scheme Registration . . . . . . . . . . . . . . . . . 55 |
| 6.4.2. Monitoring Connections for Error Status Messages . . . 54 |  | 7.3. Internet Media Type Registrations . . . . . . . . . . . . 56 |
| 6.4.3. Use of the 100 (Continue) Status . . . . . . . . . . . 54 |  | 7.3.1. Internet Media Type message/http . . . . . . . . . . . 56 |
| 6.4.4. Closing Connections on Error . . . . . . . . . . . . . 56 |  | 7.3.2. Internet Media Type application/http . . . . . . . . . 57 |
| 6.5. Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 56 |  | 7.4. Transfer Coding Registry . . . . . . . . . . . . . . . . . 58 |
| 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58 |  | 7.5. Transfer Coding Registrations . . . . . . . . . . . . . . 58 |
| 7.1. Header Field Registration . . . . . . . . . . . . . . . . 58 |  | 7.6. Upgrade Token Registry . . . . . . . . . . . . . . . . . . 59 |
| 7.2. URI Scheme Registration . . . . . . . . . . . . . . . . . 59 |  | 7.7. Upgrade Token Registration . . . . . . . . . . . . . . . . 60 |
| 7.3. Internet Media Type Registrations . . . . . . . . . . . . 59 |  | 8. Security Considerations . . . . . . . . . . . . . . . . . . . 60 |
| 7.3.1. Internet Media Type message/http . . . . . . . . . . . 59 |  | 8.1. Personal Information . . . . . . . . . . . . . . . . . . . 60 |
| 7.3.2. Internet Media Type application/http . . . . . . . . . 60 |  | 8.2. Abuse of Server Log Information . . . . . . . . . . . . . 60 |
| 7.4. Transfer Coding Registry . . . . . . . . . . . . . . . . . 61 |  | 8.3. Attacks Based On File and Path Names . . . . . . . . . . . 61 |
| 7.5. Transfer Coding Registrations . . . . . . . . . . . . . . 62 |  | 8.4. DNS-related Attacks . . . . . . . . . . . . . . . . . . . 61 |
| 7.6. Upgrade Token Registry . . . . . . . . . . . . . . . . . . 62 |  | 8.5. Intermediaries and Caching . . . . . . . . . . . . . . . . 61 |
| 7.7. Upgrade Token Registration . . . . . . . . . . . . . . . . 63 |  | 8.6. Protocol Element Size Overflows . . . . . . . . . . . . . 62 |
| 8. Security Considerations . . . . . . . . . . . . . . . . . . . 63 |  | 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 62 |
| 8.1. Personal Information . . . . . . . . . . . . . . . . . . . 63 |  | 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 64 |
| 8.2. Abuse of Server Log Information . . . . . . . . . . . . . 64 |  | 10.1. Normative References . . . . . . . . . . . . . . . . . . . 64 |
| 8.3. Attacks Based On File and Path Names . . . . . . . . . . . 64 |  | 10.2. Informative References . . . . . . . . . . . . . . . . . . 65 |
| 8.4. DNS-related Attacks . . . . . . . . . . . . . . . . . . . 65 |  | Appendix A. HTTP Version History . . . . . . . . . . . . . . . . 67 |
| 8.5. Intermediaries and Caching . . . . . . . . . . . . . . . . 65 |  | A.1. Changes from HTTP/1.0 . . . . . . . . . . . . . . . . . . 67 |
| 8.6. Protocol Element Size Overflows . . . . . . . . . . . . . 65 |  | A.1.1. Multi-homed Web Servers . . . . . . . . . . . . . . . 68 |
| 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 66 |  | A.1.2. Keep-Alive Connections . . . . . . . . . . . . . . . . 68 |
| 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 67 |  | A.1.3. Introduction of Transfer-Encoding . . . . . . . . . . 69 |
| 10.1. Normative References . . . . . . . . . . . . . . . . . . . 67 |  | A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 69 |
| 10.2. Informative References . . . . . . . . . . . . . . . . . . 68 |  | Appendix B. ABNF list extension: #rule . . . . . . . . . . . . . 70 |
| Appendix A. HTTP Version History . . . . . . . . . . . . . . . . 71 |  | Appendix C. Collected ABNF . . . . . . . . . . . . . . . . . . . 71 |
| A.1. Changes from HTTP/1.0 . . . . . . . . . . . . . . . . . . 71 |  |  |
| A.1.1. Multi-homed Web Servers . . . . . . . . . . . . . . . 72 |  |  |
| A.1.2. Keep-Alive Connections . . . . . . . . . . . . . . . . 72 |  |  |
| A.1.3. Introduction of Transfer-Encoding . . . . . . . . . . 73 |  |  |
| A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 73 |  |  |
| Appendix B. ABNF list extension: #rule . . . . . . . . . . . . . 74 |  |  |
| Appendix C. Collected ABNF . . . . . . . . . . . . . . . . . . . 75 |  |  |
| Appendix D. Change Log (to be removed by RFC Editor before |  | Appendix D. Change Log (to be removed by RFC Editor before |
| publication) . . . . . . . . . . . . . . . . . . . . 78 |  | publication) . . . . . . . . . . . . . . . . . . . . 74 |
| D.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 78 |  | D.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 74 |
| D.2. Since draft-ietf-httpbis-p1-messaging-00 . . . . . . . . . 78 |  | D.2. Since draft-ietf-httpbis-p1-messaging-00 . . . . . . . . . 74 |
| D.3. Since draft-ietf-httpbis-p1-messaging-01 . . . . . . . . . 79 |  | D.3. Since draft-ietf-httpbis-p1-messaging-01 . . . . . . . . . 75 |
| D.4. Since draft-ietf-httpbis-p1-messaging-02 . . . . . . . . . 80 |  | D.4. Since draft-ietf-httpbis-p1-messaging-02 . . . . . . . . . 76 |
| D.5. Since draft-ietf-httpbis-p1-messaging-03 . . . . . . . . . 81 |  | D.5. Since draft-ietf-httpbis-p1-messaging-03 . . . . . . . . . 77 |
| D.6. Since draft-ietf-httpbis-p1-messaging-04 . . . . . . . . . 81 |  | D.6. Since draft-ietf-httpbis-p1-messaging-04 . . . . . . . . . 77 |
| D.7. Since draft-ietf-httpbis-p1-messaging-05 . . . . . . . . . 82 |  | D.7. Since draft-ietf-httpbis-p1-messaging-05 . . . . . . . . . 78 |
| D.8. Since draft-ietf-httpbis-p1-messaging-06 . . . . . . . . . 83 |  | D.8. Since draft-ietf-httpbis-p1-messaging-06 . . . . . . . . . 79 |
| D.9. Since draft-ietf-httpbis-p1-messaging-07 . . . . . . . . . 83 |  | D.9. Since draft-ietf-httpbis-p1-messaging-07 . . . . . . . . . 79 |
| D.10. Since draft-ietf-httpbis-p1-messaging-08 . . . . . . . . . 84 |  | D.10. Since draft-ietf-httpbis-p1-messaging-08 . . . . . . . . . 80 |
| D.11. Since draft-ietf-httpbis-p1-messaging-09 . . . . . . . . . 84 |  | D.11. Since draft-ietf-httpbis-p1-messaging-09 . . . . . . . . . 80 |
| D.12. Since draft-ietf-httpbis-p1-messaging-10 . . . . . . . . . 85 |  | D.12. Since draft-ietf-httpbis-p1-messaging-10 . . . . . . . . . 81 |
| D.13. Since draft-ietf-httpbis-p1-messaging-11 . . . . . . . . . 85 |  | D.13. Since draft-ietf-httpbis-p1-messaging-11 . . . . . . . . . 81 |
| D.14. Since draft-ietf-httpbis-p1-messaging-12 . . . . . . . . . 86 |  | D.14. Since draft-ietf-httpbis-p1-messaging-12 . . . . . . . . . 82 |
| D.15. Since draft-ietf-httpbis-p1-messaging-13 . . . . . . . . . 86 |  | D.15. Since draft-ietf-httpbis-p1-messaging-13 . . . . . . . . . 82 |
| D.16. Since draft-ietf-httpbis-p1-messaging-14 . . . . . . . . . 87 |  | D.16. Since draft-ietf-httpbis-p1-messaging-14 . . . . . . . . . 83 |
| D.17. Since draft-ietf-httpbis-p1-messaging-15 . . . . . . . . . 87 |  | D.17. Since draft-ietf-httpbis-p1-messaging-15 . . . . . . . . . 83 |
| D.18. Since draft-ietf-httpbis-p1-messaging-16 . . . . . . . . . 87 |  | D.18. Since draft-ietf-httpbis-p1-messaging-16 . . . . . . . . . 83 |
| D.19. Since draft-ietf-httpbis-p1-messaging-17 . . . . . . . . . 88 |  | D.19. Since draft-ietf-httpbis-p1-messaging-17 . . . . . . . . . 84 |
| D.20. Since draft-ietf-httpbis-p1-messaging-18 . . . . . . . . . 88 |  | D.20. Since draft-ietf-httpbis-p1-messaging-18 . . . . . . . . . 84 |
| D.21. Since draft-ietf-httpbis-p1-messaging-19 . . . . . . . . . 89 |  | D.21. Since draft-ietf-httpbis-p1-messaging-19 . . . . . . . . . 84 |
| Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 |  | D.22. Since draft-ietf-httpbis-p1-messaging-20 . . . . . . . . . 85 |
|  |  | Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 |
| 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. This document is the first in a |  | hypertext information systems. This document is the first in a |
| series of documents that collectively form the HTTP/1.1 |  | series of documents that collectively form the HTTP/1.1 |
| specification: |  | specification: |
| RFC xxx1: Message Routing and Syntax |  | RFC xxx1: Message Syntax and Routing |
| RFC xxx2: Semantics and Payloads |  | RFC xxx2: Semantics and Content |
| RFC xxx3: Conditional Requests |  | RFC xxx3: Conditional Requests |
| RFC xxx4: Range Requests |  | RFC xxx4: Range Requests |
| RFC xxx5: Caching |  | RFC xxx5: Caching |
| RFC xxx6: Authentication |  | RFC xxx6: Authentication |
| This HTTP/1.1 specification obsoletes and moves to historic status |  | This HTTP/1.1 specification obsoletes and moves to historic status |
| skipping to change at page 7, line 23 |  | skipping to change at page 6, line 23 |
| handling that are independent of message semantics, thereby defining |  | handling that are independent of message semantics, thereby defining |
| the complete set of requirements for message parsers and message- |  | the complete set of requirements for message parsers and message- |
| forwarding intermediaries. |  | 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]. |
|  |  | Conformance criteria and considerations regarding error handling are |
|  |  | defined in Section 2.5. |
| 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 |
| Appendix B. Appendix C shows the collected ABNF with the list rule |  | Appendix B. Appendix C shows the collected ABNF with the list 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), |
| skipping to change at page 7, line 51 |  | skipping to change at page 7, line 9 |
| HTTP was created for the World Wide Web architecture and has evolved |  | HTTP was created for the World Wide Web architecture and has evolved |
| over time to support the scalability needs of a worldwide hypertext |  | over time to support the scalability needs of a worldwide hypertext |
| system. Much of that architecture is reflected in the terminology |  | system. Much of that architecture is reflected in the terminology |
| and syntax productions used to define HTTP. |  | and syntax productions used to define HTTP. |
| 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" (Section 6). An HTTP "client" is a |
| establishes a connection to a server for the purpose of sending one |  | program that establishes a connection to a server for the purpose of |
| or more HTTP requests. An HTTP "server" is a program that accepts |  | sending one or more HTTP requests. An HTTP "server" is a program |
| connections in order to service HTTP requests by sending HTTP |  | that accepts connections in order to service HTTP requests by sending |
| responses. |  | HTTP responses. |
| The terms client and server refer only to the roles that these |  | The terms client and server refer only to the roles that these |
| programs perform for a particular connection. The same program might |  | programs perform for a particular connection. The same program might |
| act as a client on some connections and a server on others. We use |  | act as a client on some connections and a server on others. We 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 |
| skipping to change at page 9, line 6 |  | skipping to change at page 8, line 11 |
| A server responds to a client's request by sending one or more HTTP |  | A server responds to a client's request by sending one or more HTTP |
| response messages, each beginning with a status line that includes |  | response messages, each beginning with a status line that includes |
| the protocol version, a success or error code, and textual reason |  | the protocol version, a success or error code, and textual reason |
| phrase (Section 3.1.2), possibly followed by header fields containing |  | phrase (Section 3.1.2), possibly followed by header fields containing |
| server information, resource metadata, and representation metadata |  | server information, resource metadata, and representation metadata |
| (Section 3.2), an empty line to indicate the end of the header |  | (Section 3.2), an empty line to indicate the end of the header |
| section, and finally a message body containing the payload body (if |  | section, and finally a message body containing the payload body (if |
| any, Section 3.3). |  | any, Section 3.3). |
|  |  | A connection might be used for multiple request/response exchanges, |
|  |  | as defined in Section 6.2. |
| 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-Language: en, mi |  | Accept-Language: en, mi |
| skipping to change at page 9, line 36 |  | skipping to change at page 8, line 44 |
| Content-Type: text/plain |  | Content-Type: text/plain |
| Hello World! |  | Hello World! |
| 2.2. Implementation Diversity |  | 2.2. Implementation Diversity |
| When considering the design of HTTP, it is easy to fall into a trap |  | 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 |  | of thinking that all user agents are general-purpose browsers and all |
| origin servers are large public websites. That is not the case in |  | origin servers are large public websites. That is not the case in |
| practice. Common HTTP user agents include household appliances, |  | practice. Common HTTP user agents include household appliances, |
| stereos, scales, software/firmware updaters, command-line programs, |  | stereos, scales, firmware update scripts, command-line programs, |
| mobile apps, and communication devices in a multitude of shapes and |  | mobile apps, and communication devices in a multitude of shapes and |
| sizes. Likewise, common HTTP origin servers include home automation |  | sizes. Likewise, common HTTP origin servers include home automation |
| units, configurable networking components, office machines, |  | units, configurable networking components, office machines, |
| autonomous robots, news feeds, traffic cameras, ad selectors, and |  | autonomous robots, news feeds, traffic cameras, ad selectors, and |
| video delivery platforms. |  | video delivery platforms. |
| The term "user agent" does not imply that there is a human user |  | The term "user agent" does not imply that there is a human user |
| directly interacting with the software agent at the time of a |  | directly interacting with the software agent at the time of a |
| request. In many cases, a user agent is installed or configured to |  | request. In many cases, a user agent is installed or configured to |
| run in the background and save its results for later inspection (or |  | run in the background and save its results for later inspection (or |
| save only a subset of those results that might be interesting or |  | save only a subset of those results that might be interesting or |
| erroneous). Spiders, for example, are typically given a start URI |  | erroneous). Spiders, for example, are typically given a start URI |
| and configured to follow certain behavior while crawling the Web as a |  | and configured to follow certain behavior while crawling the Web as a |
| hypertext graph. |  | hypertext graph. |
| The implementation diversity of HTTP means that we cannot assume the |  | The implementation diversity of HTTP means that we cannot assume the |
| user agent can make interactive suggestions to a user or provide |  | user agent can make interactive suggestions to a user or provide |
| adequate warning for security or privacy options. In the few cases |  | adequate warning for security or privacy options. In the few cases |
| where this specification requires reporting of errors to the user, it |  | where this specification requires reporting of errors to the user, it |
| is acceptable for such reporting to only be visible in an error |  | is acceptable for such reporting to only be observable in an error |
| console or log file. Likewise, requirements that an automated action |  | console or log file. Likewise, requirements that an automated action |
| be confirmed by the user before proceeding can me met via advance |  | be confirmed by the user before proceeding can me met via advance |
| configuration choices, run-time options, or simply not proceeding |  | configuration choices, run-time options, or simply not proceeding |
| with the unsafe action. |  | with the unsafe action. |
| 2.3. Connections and Transport Independence |  | 2.3. Intermediaries |
| HTTP messaging is independent of the underlying transport or session- |  |  |
| layer connection protocol(s). HTTP only presumes a reliable |  |  |
| transport with in-order delivery of requests and the corresponding |  |  |
| in-order delivery of responses. The mapping of HTTP request and |  |  |
| response structures onto the data units of the underlying transport |  |  |
| protocol is outside the scope of this specification. |  |  |
| The specific connection protocols to be used for an interaction are |  |  |
| determined by client configuration and the target URI (Section 5.1). |  |  |
| 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 |  |  |
| the client might be configured to use a proxy via some other |  |  |
| connection port or protocol instead of using the defaults. |  |  |
| A connection might be used for multiple HTTP request/response |  |  |
| exchanges, as defined in Section 6.3. |  |  |
| 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 |
| < < < < |  | < < < < |
| skipping to change at page 11, line 22 |  | skipping to change at page 10, line 12 |
| terms inbound and outbound to refer to directions in relation to the |  | terms inbound and outbound to refer to directions in relation to the |
| request path: "inbound" means toward the origin server and "outbound" |  | request path: "inbound" means toward the origin server and "outbound" |
| means toward the user agent. |  | means toward the user agent. |
| A "proxy" is a message forwarding agent that is selected by the |  | A "proxy" is a message forwarding agent that is selected by the |
| client, usually via local configuration rules, to receive requests |  | client, usually via local configuration rules, to receive requests |
| for some type(s) of absolute URI and attempt to satisfy those |  | for some type(s) of absolute URI and attempt to satisfy those |
| requests via translation through the HTTP interface. Some |  | requests via translation through the HTTP interface. Some |
| translations are minimal, such as for proxy requests for "http" URIs, |  | translations are minimal, such as for proxy requests for "http" URIs, |
| whereas other requests might require translation to and from entirely |  | whereas other requests might require translation to and from entirely |
| different application-layer protocols. Proxies are often used to |  | different application-level protocols. Proxies are often used to |
| group an organization's HTTP requests through a common intermediary |  | group an organization's HTTP requests through a common intermediary |
| for the sake of security, annotation services, or shared caching. |  | for the sake of security, annotation services, or shared caching. |
| An HTTP-to-HTTP proxy is called a "transforming proxy" if it is |  | An HTTP-to-HTTP proxy is called a "transforming proxy" if it is |
| designed or configured to modify request or response messages in a |  | designed or configured to modify request or response messages in a |
| semantically meaningful way (i.e., modifications, beyond those |  | semantically meaningful way (i.e., modifications, beyond those |
| required by normal HTTP processing, that change the message in a way |  | required by normal HTTP processing, that change the message in a way |
| 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 4.4.4 of [Part2] and Section 7.6 of [Part6] |  | semantics. See Section 7.3.4 of [Part2] and Section 7.5 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. |
| A gateway behaves as an origin server on its outbound connection and |  | A gateway behaves as an origin server on its outbound connection and |
| as a user agent on its inbound connection. All HTTP requirements |  | as a user agent on its inbound connection. All HTTP requirements |
| applicable to an origin server also apply to the outbound |  | applicable to an origin server also apply to the outbound |
| communication of a gateway. A gateway communicates with inbound |  | communication of a gateway. A gateway communicates with inbound |
| servers using any protocol that it desires, including private |  | servers using any protocol that it desires, including private |
| extensions to HTTP that are outside the scope of this specification. |  | extensions to HTTP that are outside the scope of this specification. |
| However, an HTTP-to-HTTP gateway that wishes to interoperate with |  | However, an HTTP-to-HTTP gateway that wishes to interoperate with |
| third-party HTTP servers MUST conform to HTTP user agent requirements |  | third-party HTTP servers MUST conform to HTTP user agent requirements |
| on the gateway's inbound connection and MUST implement the Connection |  | on the gateway's inbound connection and MUST implement the Connection |
| (Section 6.1) and Via (Section 6.2) header fields for both |  | (Section 6.1) and Via (Section 5.7) header fields for both |
| connections. |  | connections. |
| 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 (TLS, [RFC5246]) is used to establish |
| through a shared firewall proxy. |  | confidential communication through a shared firewall proxy. |
| The above categories for intermediary only consider those acting as |  | The above categories for intermediary only consider those acting as |
| participants in the HTTP communication. There are also |  | participants in the HTTP communication. There are also |
| intermediaries that can act on lower layers of the network protocol |  | intermediaries that can act on lower layers of the network protocol |
| stack, filtering or redirecting HTTP traffic without the knowledge or |  | stack, filtering or redirecting HTTP traffic without the knowledge or |
| permission of message senders. Network intermediaries often |  | permission of message senders. Network intermediaries often |
| introduce security flaws or interoperability problems by violating |  | introduce security flaws or interoperability problems by violating |
| HTTP semantics. For example, an "interception proxy" [RFC3040] (also |  | HTTP semantics. For example, an "interception proxy" [RFC3040] (also |
| commonly known as a "transparent proxy" [RFC1919] or "captive |  | commonly known as a "transparent proxy" [RFC1919] or "captive |
| portal") differs from an HTTP proxy because it is not selected by the |  | portal") differs from an HTTP proxy because it is not selected by the |
| skipping to change at page 13, line 5 |  | skipping to change at page 11, line 41 |
| 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. |
| 2.5. Caches |  | 2.4. 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 |
| skipping to change at page 13, line 39 |  | skipping to change at page 12, line 26 |
| 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. |
| 2.6. Conformance and Error Handling |  | 2.5. 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. |
|  |  | Additional (social) requirements are placed on implementations, |
|  |  | resource owners, and protocol element registrations when they apply |
|  |  | beyond the scope of a single communication. |
| The verb "generate" is used instead of "send" where a requirement |  | The verb "generate" is used instead of "send" where a requirement |
| differentiates between creating a protocol element and merely |  | differentiates between creating a protocol element and merely |
| forwarding a received element downstream. |  | 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. Note |  | the requirements associated with the roles it partakes in HTTP. Note |
| that SHOULD-level requirements are relevant here, unless one of the |  | that SHOULD-level requirements are relevant here, unless one of the |
| documented exceptions is applicable. |  | documented exceptions is applicable. |
| In addition to the prose requirements placed upon them, senders MUST |  | Conformance applies to both the syntax and semantics of HTTP protocol |
| NOT generate protocol elements that do not match the grammar defined |  | elements. A sender MUST NOT generate protocol elements that convey a |
| by the ABNF rules for those protocol elements that are applicable to |  | meaning that is known by that sender to be false. A sender MUST NOT |
| the sender's role. If a received protocol element is processed, the |  | 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 |  | recipient MUST be able to parse any value that would match the ABNF |
| rules for that protocol element, excluding only those rules not |  | rules for that protocol element, excluding only those rules not |
| applicable to the recipient's role. |  | applicable to the recipient's role. |
| Unless noted otherwise, a recipient 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. |
| 2.7. Protocol Versioning |  | 2.6. 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. |
| skipping to change at page 16, line 33 |  | skipping to change at page 15, line 26 |
| 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. |
| 2.8. Uniform Resource Identifiers |  | 2.7. 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 (Section 2 of [Part2]). |
| to target requests, indicate redirects, and define relationships. |  | URI references are used to target requests, indicate redirects, and |
| HTTP does not limit what a resource might be; it merely defines an |  | define relationships. |
| 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 |  |  |
| [RFC3986]. |  |  |
| This specification adopts the definitions of "URI-reference", |  | This specification adopts the definitions of "URI-reference", |
| "absolute-URI", "relative-part", "port", "host", "path-abempty", |  | "absolute-URI", "relative-part", "port", "host", "path-abempty", |
| "path-absolute", "query", and "authority" from the URI generic syntax |  | "path-absolute", "query", and "authority" from the URI generic |
| [RFC3986]. In addition, we define a partial-URI rule for protocol |  | syntax. In addition, we define a partial-URI rule for protocol |
| elements that allow a relative URI but not a fragment. |  | elements that allow a relative URI but not a fragment. |
| URI-reference = <URI-reference, defined in [RFC3986], Section 4.1> |  | URI-reference = <URI-reference, defined in [RFC3986], Section 4.1> |
| absolute-URI = <absolute-URI, defined in [RFC3986], Section 4.3> |  | absolute-URI = <absolute-URI, defined in [RFC3986], Section 4.3> |
| relative-part = <relative-part, defined in [RFC3986], Section 4.2> |  | relative-part = <relative-part, defined in [RFC3986], Section 4.2> |
| authority = <authority, defined in [RFC3986], Section 3.2> |  | authority = <authority, defined in [RFC3986], Section 3.2> |
| path-abempty = <path-abempty, defined in [RFC3986], Section 3.3> |  | path-abempty = <path-abempty, defined in [RFC3986], Section 3.3> |
| path-absolute = <path-absolute, defined in [RFC3986], Section 3.3> |  | path-absolute = <path-absolute, defined in [RFC3986], Section 3.3> |
| port = <port, defined in [RFC3986], Section 3.2.3> |  | port = <port, defined in [RFC3986], Section 3.2.3> |
| query = <query, defined in [RFC3986], Section 3.4> |  | query = <query, defined in [RFC3986], Section 3.4> |
| skipping to change at page 17, line 24 |  | skipping to change at page 16, line 10 |
| 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). |
| 2.8.1. http URI scheme |  | 2.7.1. 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 |
| skipping to change at page 18, line 17 |  | skipping to change at page 17, line 4 |
| the ability to place an HTTP server at that Internet name or address) |  | the ability to place an HTTP server at that Internet name or address) |
| and allows that authority to determine which names are valid and how |  | and allows that authority to determine which names are valid and how |
| they might be used. |  | they might be used. |
| When an "http" URI is used within a context that calls for access to |  | When an "http" URI is used within a context that calls for access to |
| the indicated resource, a client MAY attempt access by resolving the |  | the indicated resource, a client MAY attempt access by resolving the |
| host to an IP address, establishing a TCP connection to that address |  | host to an IP address, establishing a TCP connection to that address |
| on the indicated port, and sending an HTTP request message |  | on the indicated port, and sending an HTTP request message |
| (Section 3) containing the URI's identifying data (Section 5) to the |  | (Section 3) containing the URI's identifying data (Section 5) to the |
| server. If the server responds to that request with a non-interim |  | server. If the server responds to that request with a non-interim |
| HTTP response message, as described in Section 4 of [Part2], then |  | HTTP response message, as described in Section 7 of [Part2], then |
| that response is considered an authoritative answer to the client's |  | that response is considered an authoritative answer to the client's |
| request. |  | request. |
| Although HTTP is independent of the transport protocol, the "http" |  | Although HTTP is independent of the transport protocol, the "http" |
| scheme is specific to TCP-based services because the name delegation |  | scheme is specific to TCP-based services because the name delegation |
| process depends on TCP for establishing authority. An HTTP service |  | process depends on TCP for establishing authority. An HTTP service |
| based on some other underlying connection protocol would presumably |  | based on some other underlying connection protocol would presumably |
| be identified using a different URI scheme, just as the "https" |  | be identified using a different URI scheme, just as the "https" |
| scheme (below) is used for servers that require an SSL/TLS transport |  | scheme (below) is used for resources that require an end-to-end |
| layer on a connection. Other protocols might also be used to provide |  | secured connection. Other protocols might also be used to provide |
| access to "http" identified resources -- it is only the authoritative |  | access to "http" identified resources -- it is only the authoritative |
| interface used for mapping the namespace that is specific to TCP. |  | interface used for mapping the namespace that is specific to TCP. |
| The URI generic syntax for authority also includes a deprecated |  | The URI generic syntax for authority also includes a deprecated |
| userinfo subcomponent ([RFC3986], Section 3.2.1) for including user |  | userinfo subcomponent ([RFC3986], Section 3.2.1) for including user |
| authentication information in the URI. Some implementations make use |  | authentication information in the URI. Some implementations make use |
| of the userinfo component for internal configuration of |  | of the userinfo component for internal configuration of |
| 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. |
| 2.8.2. https URI scheme |  | 2.7.2. 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 to a |
| SSL/TLS-secured connections on a given TCP port. |  | given TCP port for TLS-secured connections [RFC5246]. |
| 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, end-to-end, 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 7.2 of [Part6]). |  | Cache-Control header field (Section 7.2 of [Part6]). |
| skipping to change at page 19, line 32 |  | skipping to change at page 18, line 18 |
| 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]. |
| 2.8.3. http and https URI Normalization and Comparison |  | 2.7.3. 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 21, line 10 |  | skipping to change at page 19, line 44 |
| (for requests) or a status-line (for responses), and in the algorithm |  | (for requests) or a status-line (for responses), and in the algorithm |
| for determining the length of the message body (Section 3.3). In |  | for determining the length of the message body (Section 3.3). In |
| theory, a client could receive requests and a server could receive |  | theory, a client could receive requests and a server could receive |
| responses, distinguishing them by their different start-line formats, |  | responses, distinguishing them by their different start-line formats, |
| but in practice servers are implemented to only expect a request (a |  | but in practice servers are implemented to only expect a request (a |
| response is interpreted as an unknown or invalid request method) and |  | response is interpreted as an unknown or invalid request method) and |
| clients are implemented to only expect a response. |  | clients are implemented to only expect a response. |
| start-line = request-line / status-line |  | start-line = request-line / status-line |
| Implementations MUST NOT send whitespace between the start-line and |  | A sender MUST NOT send whitespace between the start-line and the |
| the first header field. The presence of such whitespace in a request |  | first header field. The presence of such whitespace in a request |
| might be an attempt to trick a server into ignoring that field or |  | might be an attempt to trick a server into ignoring that field or |
| processing the line after it as a new request, either of which might |  | processing the line after it as a new request, either of which might |
| result in a security vulnerability if other implementations within |  | result in a security vulnerability if other implementations within |
| the request chain interpret the same message differently. Likewise, |  | the request chain interpret the same message differently. Likewise, |
| the presence of such whitespace in a response might be ignored by |  | the presence of such whitespace in a response might be ignored by |
| 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 |
| skipping to change at page 21, line 35 |  | skipping to change at page 20, line 21 |
| 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 server MUST be able to parse any received message that begins with |
| a request-line and matches the ABNF rule for HTTP-message. |  | 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 5 |
| 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 |
| the request, as defined in Section 5.3. |  | the request, as defined in Section 5.3. |
| No whitespace is allowed inside the method, request-target, and |  | No whitespace is allowed inside the method, request-target, and |
| protocol version. Hence, recipients typically parse the request-line |  | protocol version. Hence, recipients typically parse the request-line |
| into its component parts by splitting on the SP characters. |  | into its component parts by splitting on the SP characters. |
| skipping to change at page 22, line 15 |  | skipping to change at page 20, line 49 |
| 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 405 (Method Not Allowed), if |  | implements SHOULD respond with either a 405 (Method Not Allowed), if |
| it is an origin server, or a 501 (Not Implemented) status code. A |  | it is an origin server, or a 501 (Not Implemented) status code. A |
| server MUST be prepared to receive URIs of unbounded length and |  | server MUST be prepared to receive URIs of unbounded length and |
| respond with the 414 (URI Too Long) status code if the received |  | respond with the 414 (URI Too Long) status code if the received |
| request-target would be longer than the server wishes to handle (see |  | request-target would be longer than the server wishes to handle (see |
| Section 4.6.12 of [Part2]). |  | Section 7.5.12 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, |
| skipping to change at page 22, line 37 |  | skipping to change at page 21, line 22 |
| status-line = HTTP-version SP status-code SP reason-phrase CRLF |  | status-line = HTTP-version SP status-code SP reason-phrase CRLF |
| A client MUST be able to parse any received message that begins with |  | A client MUST be able to parse any received message that begins with |
| a status-line and matches the ABNF rule for HTTP-message. |  | a status-line and matches the ABNF rule for HTTP-message. |
| The status-code element is a 3-digit integer code describing the |  | The status-code element is a 3-digit integer code describing the |
| result of the server's attempt to understand and satisfy the client's |  | result of the server's attempt to understand and satisfy the client's |
| corresponding request. The rest of the response message is to be |  | corresponding request. The rest of the response message is to be |
| interpreted in light of the semantics defined for that status code. |  | interpreted in light of the semantics defined for that status code. |
| See Section 4 of [Part2] for information about the semantics of |  | See Section 7 of [Part2] for information about the semantics of |
| status codes, including the classes of status code (indicated by the |  | status codes, including the classes of status code (indicated by the |
| first digit), the status codes defined by this specification, |  | first digit), the status codes defined by this specification, |
| considerations for the definition of new status codes, and the IANA |  | considerations for the definition of new status codes, and the IANA |
| registry. |  | 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 |
| skipping to change at page 23, line 20 |  | skipping to change at page 22, line 5 |
| 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 9.10 of [Part2] as containing the |  | header field is defined in Section 8.1.1.2 of [Part2] as containing |
| origination timestamp for the message in which it appears. |  | the 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. |
| New HTTP header fields SHOULD be registered with IANA according to |  | New HTTP header fields SHOULD be registered with IANA in the Message |
| the procedures in Section 3.1 of [Part2]. Unrecognized header fields |  | Header Field Registry, as described in Section 9.3 of [Part2]. |
| MUST be forwarded by a proxy unless the field-name is listed in the |  | Unrecognized header fields MUST be forwarded by a proxy unless the |
| Connection header field (Section 6.1) or the proxy is specifically |  | field-name is listed in the Connection header field (Section 6.1) or |
| configured to block or otherwise transform such fields. Unrecognized |  | the proxy is specifically configured to block or otherwise transform |
| header fields SHOULD be ignored by other recipients. |  | such fields. Unrecognized header fields SHOULD be ignored by other |
|  |  | recipients. |
| The order in which header fields with differing field names are |  | The order in which header fields with differing field names are |
| received is not significant. However, it is "good practice" to send |  | received is not significant. However, it is "good practice" to send |
| header fields that contain control data first, such as Host on |  | header fields that contain control data first, such as Host on |
| requests and Date on responses, so that implementations can decide |  | requests and Date on responses, so that implementations can decide |
| when not to handle a message as early as possible. A server MUST |  | when not to handle a message as early as possible. A server MUST |
| wait until the entire header section is received before interpreting |  | wait until the entire header section is received before interpreting |
| a request message, since later header fields might include |  | a request message, since later header fields might include |
| conditionals, authentication credentials, or deliberately misleading |  | conditionals, authentication credentials, or deliberately misleading |
| duplicate header fields that would impact request processing. |  | duplicate header fields that would impact request processing. |
| skipping to change at page 24, line 37 |  | skipping to change at page 23, line 24 |
| SHOULD either be replaced with a single SP or transformed to all SP |  | SHOULD either be replaced with a single SP or transformed to all SP |
| octets (each octet other than SP replaced with SP) before |  | octets (each octet other than SP replaced with SP) before |
| interpreting the field value or forwarding the message downstream. |  | interpreting the field value or forwarding the message downstream. |
| RWS is used when at least one linear whitespace octet is required to |  | RWS is used when at least one linear whitespace octet is required to |
| separate field tokens. RWS SHOULD be produced as a single SP. |  | separate field tokens. RWS SHOULD be produced as a single SP. |
| Multiple RWS octets that occur within field-content SHOULD either be |  | Multiple RWS octets that occur within field-content SHOULD either be |
| replaced with a single SP or transformed to all SP octets before |  | replaced with a single SP or transformed to all SP octets before |
| interpreting the field value or forwarding the message downstream. |  | interpreting the field value or forwarding the message downstream. |
| BWS is used where the grammar allows optional whitespace for |  | BWS is used where the grammar allows optional whitespace, for |
| historical reasons but senders SHOULD NOT produce it in messages. |  | historical reasons, but senders SHOULD NOT produce it in messages; |
| HTTP/1.1 recipients MUST accept such bad optional whitespace and |  | recipients MUST accept such bad optional whitespace and remove it |
| remove it before interpreting the field value or forwarding the |  | before interpreting the field value or forwarding the message |
| message downstream. |  | downstream. |
| OWS = *( SP / HTAB ) |  | OWS = *( SP / HTAB ) |
| ; "optional" whitespace |  | ; "optional" whitespace |
| RWS = 1*( SP / HTAB ) |  | RWS = 1*( SP / HTAB ) |
| ; "required" whitespace |  | ; "required" whitespace |
| BWS = OWS |  | BWS = OWS |
| ; "bad" whitespace |  | ; "bad" whitespace |
| 3.2.2. Field Parsing |  | 3.2.2. Field Parsing |
| skipping to change at page 26, line 12 |  | skipping to change at page 24, line 45 |
| A client that receives response header fields 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 field length are found in |  | Various ad-hoc limitations on header field 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 messages whose combined header fields have 4000 or more |  | support messages whose combined header fields have 4000 or more |
| octets. |  | 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 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 |
| token = 1*tchar |  | token = 1*tchar |
| tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" |  | tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" |
| / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~" |  | / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~" |
| skipping to change at page 27, line 38 |  | skipping to change at page 26, line 26 |
| 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 |
| (Section 3.1.2). Responses to the HEAD request method never include |  | (Section 3.1.2). Responses to the HEAD request method never include |
| a 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.), if present, indicate only |
| values would have been if the request method had been GET. 2xx |  | what their values would have been if the request method had been GET |
| (Successful) responses to CONNECT switch to tunnel mode instead of |  | (Section 5.3.2 of [Part2]). 2xx (Successful) responses to CONNECT |
| having a message body. All 1xx (Informational), 204 (No Content), |  | switch to tunnel mode instead of having a message body (Section 5.3.6 |
| and 304 (Not Modified) responses MUST NOT include a message body. |  | of [Part2]). All 1xx (Informational), 204 (No Content), and 304 (Not |
| All other responses do include a message body, although the body MAY |  | Modified) responses MUST NOT include a message body. All other |
| be of zero length. |  | responses do include a message body, although the body MAY 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. |
| Transfer codings are defined in Section 4. |  | Transfer codings are defined in Section 4. |
| Transfer-Encoding = 1#transfer-coding |  | Transfer-Encoding = 1#transfer-coding |
| skipping to change at page 28, line 40 |  | skipping to change at page 27, line 29 |
| 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 5.4 of [Part2]), Transfer-Encoding |  | Unlike Content-Encoding (Section 3.1.2.1 of [Part2]), Transfer- |
| is a property of the message, not of the payload, and thus MAY be |  | Encoding is a property of the message, not of the payload, and thus |
| added or removed by any implementation along the request/response |  | MAY be added or removed by any implementation along the request/ |
| chain. Additional information about the encoding parameters MAY be |  | response chain. Additional information about the encoding parameters |
| provided by other header fields not defined by this specification. |  | MAY be 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 (Not Modified) response (Section 4.1 of [Part4]) to a GET |  | 304 (Not Modified) response (Section 4.1 of [Part4]) to a GET |
| request, neither of which includes a message body, to indicate that |  | request, neither of which includes a message body, to indicate that |
| the origin server would have applied a transfer coding to the message |  | the origin server would have applied a transfer coding to the message |
| body if the request had been an unconditional GET. This indication |  | body if the request had been an unconditional GET. This indication |
| is not required, however, because any recipient on the response chain |  | is not required, however, because any recipient on the response chain |
| (including the origin server) can remove transfer codings when they |  | (including the origin server) can remove transfer codings when they |
| are not needed. |  | are not needed. |
| skipping to change at page 29, line 22 |  | skipping to change at page 28, line 12 |
| 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). |
| 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 is allowed to contain a message body, does not have a |
| payload body length can be determined prior to being transferred, a |  | Transfer-Encoding header field, and has a payload body length that is |
| Content-Length header field SHOULD be sent to indicate the length of |  | known to the sender before the message header section has been sent, |
| the payload body that is either present as the message body, for |  | the sender SHOULD send a Content-Length header field to indicate the |
| requests and non-HEAD responses other than 304 (Not Modified), or |  | length of the payload body as a decimal number of octets. |
| would have been present had the request been an unconditional GET. |  |  |
| 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 |  | A sender MUST NOT send a Content-Length header field in any message |
| the size of the payload body (without any potential transfer-coding) |  | that contains a Transfer-Encoding header field. |
| that would have been sent had the request been a GET. In the case of |  |  |
| a 304 (Not Modified) response (Section 4.1 of [Part4]) to a GET |  | A server MAY send a Content-Length header field in a response to a |
| request, Content-Length indicates the size of the payload body |  | HEAD request (Section 5.3.2 of [Part2]); a server MUST NOT send |
| (without any potential transfer-coding) that would have been sent in |  | Content-Length in such a response unless its field-value equals the |
| a 200 (OK) response. |  | decimal number of octets that would have been sent in the payload |
|  |  | body of a response if the same request had used the GET method. |
|  |  | A server MAY send a Content-Length header field in a 304 (Not |
|  |  | Modified) response to a conditional GET request (Section 4.1 of |
|  |  | [Part4]); a server MUST NOT send Content-Length in such a response |
|  |  | unless its field-value equals the decimal number of octets that would |
|  |  | have been sent in the payload body of a 200 (OK) response to the same |
|  |  | request. |
|  |  | A server MUST NOT send a Content-Length header field in any response |
|  |  | with a status code of 1xx (Informational) or 204 (No Content). A |
|  |  | server SHOULD NOT send a Content-Length header field in any 2xx |
|  |  | (Successful) response to a CONNECT request (Section 5.3.6 of |
|  |  | [Part2]). |
| 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 with field-values consisting of the same decimal value, or a |  | fields with field-values consisting of the same decimal value, or a |
| single Content-Length header field with a field value containing a |  | single Content-Length header field with a field value containing a |
| skipping to change at page 31, line 50 |  | skipping to change at page 31, line 4 |
| 6. If this is a request message and none of the above are true, then |  | 6. If this is a request message and none of the above are true, then |
| the message body length is zero (no message body is present). |  | the message body length is zero (no message body is present). |
| 7. Otherwise, this is a response message without a declared message |  | 7. Otherwise, this is a response message without a declared message |
| body length, so the message body length is determined by the |  | body length, so the message body length is determined by the |
| number of octets received prior to the server closing the |  | number of octets received prior to the server closing the |
| connection. |  | connection. |
| Since there is no way to distinguish a successfully completed, close- |  | Since there is no way to distinguish a successfully completed, close- |
| delimited message from a partially-received message interrupted by |  | delimited message from a partially-received message interrupted by |
| network failure, implementations SHOULD use encoding or length- |  | network failure, a server SHOULD use encoding or length-delimited |
| delimited messages whenever possible. The close-delimiting feature |  | messages whenever possible. The close-delimiting feature exists |
| exists primarily for backwards compatibility with HTTP/1.0. |  | primarily for backwards compatibility with HTTP/1.0. |
| A server MAY reject a request that contains a message body but not a |  | A server MAY reject a request that contains a message body but not a |
| Content-Length by responding with 411 (Length Required). |  | Content-Length by responding with 411 (Length Required). |
| Unless a transfer-coding other than "chunked" has been applied, a |  | Unless a transfer-coding other than "chunked" has been applied, a |
| client that sends a request containing a message body SHOULD use a |  | client that sends a request containing a message body SHOULD use a |
| valid Content-Length header field if the message body length is known |  | valid Content-Length header field if the message body length is known |
| in advance, rather than the "chunked" encoding, since some existing |  | in advance, rather than the "chunked" encoding, since some existing |
| services respond to "chunked" with a 411 (Length Required) status |  | services respond to "chunked" with a 411 (Length Required) status |
| code even though they understand the chunked encoding. This is |  | code even though they understand the chunked encoding. This is |
| skipping to change at page 32, line 30 |  | skipping to change at page 31, line 32 |
| 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 |
| canceled 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 error response prior |
| response prior to closing the connection is OPTIONAL. |  | 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. |
| A message body that uses the chunked transfer encoding is incomplete |  | A message body that uses the chunked transfer encoding is incomplete |
| skipping to change at page 33, line 14 |  | skipping to change at page 32, line 16 |
| if it were complete (i.e., some indication needs to be given to the |  | if it were complete (i.e., some indication needs to be given to the |
| user that an error occurred). Cache requirements for incomplete |  | user that an error occurred). Cache requirements for incomplete |
| responses are defined in Section 3 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 6.2.2.1. |
| 3.5. Message Parsing Robustness |  | 3.5. Message Parsing Robustness |
| Older HTTP/1.0 client implementations might send an extra CRLF after |  | Older HTTP/1.0 client implementations might send an extra CRLF after |
| a POST request as a lame workaround for some early server |  | a POST request as a lame workaround for some early server |
| applications that failed to read message body content that was not |  | applications that failed to read message body content that was not |
| terminated by a line-ending. An HTTP/1.1 client MUST NOT preface or |  | terminated by a line-ending. An HTTP/1.1 client MUST NOT preface or |
| follow a request with an extra CRLF. If terminating the request |  | follow a request with an extra CRLF. If terminating the request |
| message body with a line-ending is desired, then the client MUST |  | message body with a line-ending is desired, then the client MUST |
| include the terminating CRLF octets as part of the message body |  | include the terminating CRLF octets as part of the message body |
| skipping to change at page 34, line 18 |  | skipping to change at page 33, line 18 |
| / "gzip" ; Section 4.2.3 |  | / "gzip" ; Section 4.2.3 |
| / transfer-extension |  | / transfer-extension |
| transfer-extension = token *( OWS ";" OWS transfer-parameter ) |  | transfer-extension = token *( OWS ";" OWS transfer-parameter ) |
| Parameters are in the form of attribute/value pairs. |  | Parameters are in the form of attribute/value pairs. |
| transfer-parameter = attribute BWS "=" BWS value |  | transfer-parameter = attribute BWS "=" BWS value |
| attribute = token |  | attribute = token |
| value = word |  | value = word |
| All transfer-coding values are case-insensitive. The HTTP Transfer |  | All transfer-coding values are case-insensitive and SHOULD be |
| Coding registry is defined in Section 7.4. HTTP/1.1 uses transfer- |  | registered within the HTTP Transfer Coding registry, as defined in |
| coding values in the TE header field (Section 4.3) and in the |  | Section 7.4. They are used in the TE (Section 4.3) and Transfer- |
| Transfer-Encoding header field (Section 3.3.1). |  | Encoding (Section 3.3.1) header fields. |
| 4.1. Chunked Transfer Coding |  | 4.1. Chunked Transfer Coding |
| The chunked encoding modifies the body of a message in order to |  | The chunked encoding modifies the body of a message in order to |
| transfer it as a series of chunks, each with its own size indicator, |  | transfer it as a series of chunks, each with its own size indicator, |
| followed by an OPTIONAL trailer containing header fields. This |  | followed by an OPTIONAL trailer containing header fields. This |
| allows dynamically produced content to be transferred along with the |  | allows dynamically produced content to be transferred along with the |
| information necessary for the recipient to verify that it has |  | information necessary for the recipient to verify that it has |
| received the full message. |  | received the full message. |
| skipping to change at page 34, line 52 |  | skipping to change at page 33, line 52 |
| 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-data = 1*OCTET ; a sequence of chunk-size octets |  | chunk-data = 1*OCTET ; a sequence of chunk-size octets |
| trailer-part = *( header-field CRLF ) |  | trailer-part = *( header-field CRLF ) |
| quoted-str-nf = DQUOTE *( qdtext-nf / quoted-pair ) DQUOTE |  | quoted-str-nf = DQUOTE *( qdtext-nf / quoted-pair ) DQUOTE |
| ; like quoted-string, but disallowing line folding |  | ; like quoted-string, but disallowing line folding |
| qdtext-nf = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text |  | qdtext-nf = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text |
|  |  | Chunk extensions within the chucked encoding are deprecated. Senders |
|  |  | SHOULD NOT send chunk-ext. Definition of new chunk extensions is |
|  |  | discouraged. |
| The chunk-size field is a string of hex digits indicating the size of |  | The chunk-size field is a string of hex digits indicating the size of |
| the chunk-data in octets. The chunked encoding is ended by any chunk |  | the chunk-data in octets. The chunked encoding is ended by any chunk |
| whose size is zero, followed by the trailer, which is terminated by |  | whose size is zero, followed by the trailer, which is terminated by |
| an empty line. |  | an empty line. |
| The trailer allows the sender to include additional HTTP header |  | 4.1.1. Trailer |
| fields at the end of the message. The Trailer header field can be |  |  |
| used to indicate which header fields are included in a trailer (see |  |  |
| Section 4.4). |  |  |
| A server using chunked transfer-coding in a response MUST NOT use the |  | A trailer allows the sender to include additional fields at the end |
| trailer for any header fields unless at least one of the following is |  | of a chunked message in order to supply metadata that might be |
| true: |  | dynamically generated while the message body is sent, such as a |
|  |  | message integrity check, digital signature, or post-processing |
|  |  | status. The trailer MUST NOT contain fields that need to be known |
|  |  | before a recipient processes the body, such as Transfer-Encoding, |
|  |  | Content-Length, and Trailer. |
|  |  | When a message includes a message body encoded with the chunked |
|  |  | transfer-coding and the sender desires to send metadata in the form |
|  |  | of trailer fields at the end of the message, the sender SHOULD send a |
|  |  | Trailer header field before the message body to indicate which fields |
|  |  | will be present in the trailers. This allows the recipient to |
|  |  | prepare for receipt of that metadata before it starts processing the |
|  |  | body, which is useful if the message is being streamed and the |
|  |  | recipient wishes to confirm an integrity check on the fly. |
|  |  | Trailer = 1#field-name |
|  |  | If no Trailer header field is present, the sender of a chunked |
|  |  | message body SHOULD send an empty trailer. |
|  |  | A server MUST send an empty trailer with the chunked transfer-coding |
|  |  | unless at least one of the following is 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 that |
| other words, the server that generated the header field (often |  | metadata. In other words, the server that generated the header |
| but not always the origin server) is willing to accept the |  | field is willing to accept the possibility that the trailer |
| possibility that the trailer fields might be silently discarded |  | fields might be silently discarded along the path to the client. |
| along the path to the client. |  |  |
| This requirement prevents an interoperability failure when the |  | The above requirement prevents the need for an infinite buffer when a |
| 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. |
| conformance with the protocol would have necessitated a possibly |  |  |
| infinite buffer on the proxy. |  | 4.1.2. Decoding chunked |
| 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: |
| length := 0 |  | length := 0 |
| read chunk-size, chunk-ext (if any) and CRLF |  | read chunk-size, chunk-ext (if any) and CRLF |
| while (chunk-size > 0) { |  | while (chunk-size > 0) { |
| read chunk-data and CRLF |  | read chunk-data and CRLF |
| append chunk-data to decoded-body |  | append chunk-data to decoded-body |
| length := length + chunk-size |  | length := length + chunk-size |
| read chunk-size and CRLF |  | read chunk-size and CRLF |
| } |  | } |
| read header-field |  | read header-field |
| while (header-field not empty) { |  | while (header-field not empty) { |
| append header-field to existing header fields |  | append header-field to existing header fields |
| read header-field |  | read header-field |
| } |  | } |
| Content-Length := length |  | Content-Length := length |
| Remove "chunked" from Transfer-Encoding |  | Remove "chunked" from Transfer-Encoding |
|  |  | Remove Trailer from existing header fields |
| All HTTP/1.1 applications MUST be able to receive and decode the |  | All recipients MUST be able to receive and decode the "chunked" |
| "chunked" transfer-coding and MUST ignore chunk-ext extensions they |  | transfer-coding and MUST ignore chunk-ext extensions they do not |
| do not understand. |  | understand. |
| Use of chunk-ext extensions by senders is deprecated; they SHOULD NOT |  |  |
| be sent and definition of new chunk-extensions is discouraged. |  |  |
| 4.2. Compression Codings |  | 4.2. Compression Codings |
| The codings defined below can be used to compress the payload of a |  | The codings defined below can be used to compress the payload of a |
| message. |  | message. |
| Note: Use of program names for the identification of encoding |  |  |
| formats is not desirable and is discouraged for future encodings. |  |  |
| Their use here is representative of historical practice, not good |  |  |
| design. |  |  |
| Note: For compatibility with previous implementations of HTTP, |  |  |
| applications SHOULD consider "x-gzip" and "x-compress" to be |  |  |
| equivalent to "gzip" and "compress" respectively. |  |  |
| 4.2.1. Compress Coding |  | 4.2.1. Compress Coding |
| The "compress" format is produced by the common UNIX file compression |  | The "compress" format is produced by the common UNIX file compression |
| program "compress". This format is an adaptive Lempel-Ziv-Welch |  | program "compress". This format is an adaptive Lempel-Ziv-Welch |
| coding (LZW). |  | coding (LZW). Recipients SHOULD consider "x-compress" to be |
|  |  | equivalent to "compress". |
| 4.2.2. Deflate Coding |  | 4.2.2. Deflate Coding |
| The "deflate" format is defined as the "deflate" compression |  | The "deflate" format is defined as the "deflate" compression |
| mechanism (described in [RFC1951]) used inside the "zlib" data format |  | mechanism (described in [RFC1951]) used inside the "zlib" data format |
| ([RFC1950]). |  | ([RFC1950]). |
| Note: Some incorrect implementations send the "deflate" compressed |  | Note: Some incorrect implementations send the "deflate" compressed |
| data without the zlib wrapper. |  | data without the zlib wrapper. |
| 4.2.3. Gzip Coding |  | 4.2.3. Gzip Coding |
| The "gzip" format is produced by the file compression program "gzip" |  | The "gzip" format is produced by the file compression program "gzip" |
| (GNU zip), as described in [RFC1952]. This format is a Lempel-Ziv |  | (GNU zip), as described in [RFC1952]. This format is a Lempel-Ziv |
| coding (LZ77) with a 32 bit CRC. |  | coding (LZ77) with a 32 bit CRC. Recipients SHOULD consider "x-gzip" |
|  |  | to be equivalent to "gzip". |
| 4.3. TE |  | 4.3. TE |
| The "TE" header field indicates what extension transfer-codings the |  | The "TE" header field in a request indicates what transfer-codings, |
| client is willing to accept in the response, and whether or not it is |  | besides "chunked", the client is willing to accept in response, and |
| willing to accept trailer fields in a chunked transfer-coding. |  | whether or not the client is willing to accept trailer fields in a |
|  |  | chunked transfer-coding. |
| Its value consists of the keyword "trailers" and/or a comma-separated |  | The TE field-value consists of a comma-separated list of transfer- |
| list of extension transfer-coding names with optional accept |  | coding names, each allowing for optional parameters (as described in |
| parameters (as described in Section 4). |  | Section 4), and/or the keyword "trailers". Clients MUST NOT send the |
|  |  | chunked transfer-coding name in TE; chunked is always acceptable for |
|  |  | HTTP/1.1 recipients. |
| TE = #t-codings |  | TE = #t-codings |
| t-codings = "trailers" / ( transfer-extension [ te-params ] ) |  | t-codings = "trailers" / ( transfer-coding [ t-ranking ] ) |
| te-params = OWS ";" OWS "q=" qvalue *( te-ext ) |  | t-ranking = OWS ";" OWS "q=" rank |
| te-ext = OWS ";" OWS token [ "=" word ] |  | rank = ( "0" [ "." 0*3DIGIT ] ) |
|  |  | / ( "1" [ "." 0*3("0") ] ) |
| The presence of the keyword "trailers" indicates that the client is |  |  |
| willing to accept trailer fields in a chunked transfer-coding, as |  |  |
| defined in Section 4.1. This keyword is reserved for use with |  |  |
| transfer-coding values even though it does not itself represent a |  |  |
| transfer-coding. |  |  |
| Examples of its use are: |  | Three examples of TE use are below. |
| TE: deflate |  | TE: deflate |
| TE: |  | TE: |
| TE: trailers, deflate;q=0.5 |  | TE: trailers, deflate;q=0.5 |
| The TE header field only applies to the immediate connection. |  | The presence of the keyword "trailers" indicates that the client is |
| Therefore, the keyword MUST be supplied within a Connection header |  | willing to accept trailer fields in a chunked transfer-coding, as |
| field (Section 6.1) whenever TE is present in an HTTP/1.1 message. |  | defined in Section 4.1, on behalf of itself and any downstream |
|  |  | clients. For chained requests, this implies that either: (a) all |
| A server tests whether a transfer-coding is acceptable, according to |  | downstream clients are willing to accept trailer fields in the |
| a TE field, using these rules: |  | forwarded response; or, (b) the client will attempt to buffer the |
|  |  | response on behalf of downstream recipients. Note that HTTP/1.1 does |
| 1. The "chunked" transfer-coding is always acceptable. If the |  | not define any means to limit the size of a chunked response such |
| keyword "trailers" is listed, the client indicates that it is |  | that a client can be assured of buffering the entire response. |
| willing to accept trailer fields in the chunked response on |  |  |
| behalf of itself and any downstream clients. The implication is |  |  |
| that, if given, the client is stating that either all downstream |  |  |
| clients are willing to accept trailer fields in the forwarded |  |  |
| response, or that it will attempt to buffer the response on |  |  |
| behalf of downstream recipients. |  |  |
| Note: HTTP/1.1 does not define any means to limit the size of a |  |  |
| chunked response such that a client can be assured of buffering |  |  |
| the entire response. |  |  |
| 2. If the transfer-coding being tested is one of the transfer- |  |  |
| codings listed in the TE field, then it is acceptable unless it |  |  |
| is accompanied by a qvalue of 0. (As defined in Section 4.3.1, a |  |  |
| qvalue of 0 means "not acceptable".) |  |  |
| 3. If multiple transfer-codings are acceptable, then the acceptable |  | When multiple transfer-codings are acceptable, the client MAY rank |
| transfer-coding with the highest non-zero qvalue is preferred. |  | the codings by preference using a case-insensitive "q" parameter |
| The "chunked" transfer-coding always has a qvalue of 1. |  | (similar to the qvalues used in content negotiation fields, Section |
|  |  | 6.3.1 of [Part2]). The rank value is a real number in the range 0 |
|  |  | through 1, where 0.001 is the least preferred and 1 is the most |
|  |  | preferred; a value of 0 means "not acceptable". |
| 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 |  | Since the TE header field only applies to the immediate connection, a |
|  |  | sender of TE MUST also send a "TE" connection option within the |
| Both transfer codings (TE request header field, Section 4.3) and |  | Connection header field (Section 6.1) in order to prevent the TE |
| content negotiation (Section 8 of [Part2]) use short "floating point" |  | field from being forwarded by intermediaries that do not support its |
| numbers to indicate the relative importance ("weight") of various |  | semantics. |
| 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 |  |  |
| value. If a parameter has a quality value of 0, then content with |  |  |
| this parameter is "not acceptable" for the client. HTTP/1.1 |  |  |
| applications MUST NOT generate more than three digits after the |  |  |
| decimal point. User configuration of these values SHOULD also be |  |  |
| limited in this fashion. |  |  |
| qvalue = ( "0" [ "." 0*3DIGIT ] ) |  |  |
| / ( "1" [ "." 0*3("0") ] ) |  |  |
| Note: "Quality values" is a misnomer, since these values merely |  |  |
| represent relative degradation in desired quality. |  |  |
| 4.4. Trailer |  |  |
| The "Trailer" header field indicates that the given set of header |  |  |
| fields is present in the trailer of a message encoded with chunked |  |  |
| transfer-coding. |  |  |
| Trailer = 1#field-name |  |  |
| An HTTP/1.1 message SHOULD include a Trailer header field in a |  |  |
| message using chunked transfer-coding with a non-empty trailer. |  |  |
| Doing so allows the recipient to know which header fields to expect |  |  |
| in the trailer. |  |  |
| If no Trailer header field is present, the trailer SHOULD NOT include |  |  |
| any header fields. See Section 4.1 for restrictions on the use of |  |  |
| trailer fields in a "chunked" transfer-coding. |  |  |
| Message header fields listed in the Trailer header field MUST NOT |  |  |
| include the following header fields: |  |  |
| o Transfer-Encoding |  |  |
| o Content-Length |  |  |
| o Trailer |  |  |
| 5. Message Routing |  | 5. Message Routing |
| HTTP request message routing is determined by each client based on |  | HTTP request message routing is determined by each client based on |
| the target resource, the client's proxy configuration, and |  | the target resource, the client's proxy configuration, and |
| establishment or reuse of an inbound connection. The corresponding |  | establishment or reuse of an inbound connection. The corresponding |
| response routing follows the same connection chain back to the |  | response routing follows the same connection chain back to the |
| client. |  | client. |
| 5.1. Identifying a Target Resource |  | 5.1. Identifying a Target Resource |
| 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 2.8) is typically used as an |  | semantics. A URI reference (Section 2.7) 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 |  |  |
| the request-line of an incoming request message. |  |  |
| 5.2. Connecting Inbound |  | 5.2. Connecting Inbound |
| Once the target URI is determined, a client needs to decide whether a |  | Once the target URI is determined, a client needs to decide whether a |
| network request is necessary to accomplish the desired semantics and, |  | network request is necessary to accomplish the desired semantics and, |
| if so, where that request is to be directed. |  | if so, where that request is to be directed. |
| If the client has a response cache and the request semantics can be |  | If the client has a response cache and the request semantics can be |
| satisfied by a cache ([Part6]), then the request is usually directed |  | satisfied by a cache ([Part6]), then the request is usually directed |
| to the cache first. |  | to the cache first. |
| skipping to change at page 40, line 15 |  | skipping to change at page 38, line 20 |
| 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 2.8.1) and |  | origin server access for resolution of the "http" (Section 2.7.1) and |
| "https" (Section 2.8.2) schemes. |  | "https" (Section 2.7.2) schemes. |
|  |  | HTTP requirements regarding connection management are defined in |
|  |  | Section 6. |
| 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, the client sends an HTTP |
| an HTTP request message (Section 3) with a request-target derived |  | request message (Section 3) with a request-target derived from the |
| from the target URI. There are four distinct formats for the |  | target URI. There are four distinct formats for the request-target, |
| request-target, depending on both the method being requested and |  | depending on both the method being requested and whether the request |
| whether the request is to a proxy. |  | is to a proxy. |
| request-target = origin-form |  | request-target = origin-form |
| / absolute-form |  | / absolute-form |
| / authority-form |  | / authority-form |
| / asterisk-form |  | / asterisk-form |
| origin-form = path-absolute [ "?" query ] |  | origin-form = path-absolute [ "?" query ] |
| absolute-form = absolute-URI |  | absolute-form = absolute-URI |
| authority-form = authority |  | authority-form = authority |
| asterisk-form = "*" |  | asterisk-form = "*" |
| skipping to change at page 41, line 31 |  | skipping to change at page 39, line 39 |
| 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 2.3.8 of [Part2]). When making a CONNECT request |  | requests (Section 5.3.6 of [Part2]). When making a CONNECT request |
| to 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 2.3.1 of [Part2]). When a client wishes to |  | OPTIONS request (Section 5.3.7 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 |
| origin server. |  | origin server. |
| For example, the request |  | For example, the request |
| skipping to change at page 42, line 25 |  | skipping to change at page 40, line 32 |
| 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 2.8.1 |  | Host = uri-host [ ":" port ] ; Section 2.7.1 |
| 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 2.8.1). If the authority |  | after excluding any userinfo (Section 2.7.1). 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 |
| request-target is in the absolute-form, since this allows the Host |  | request-target is in the absolute-form, since this allows the Host |
| information to be forwarded through ancient HTTP/1.0 proxies that |  | information to be forwarded through ancient HTTP/1.0 proxies that |
| might not have implemented Host. |  | might not have implemented Host. |
| When an HTTP/1.1 proxy receives a request with an absolute-form of |  | When a proxy receives a request with an absolute-form of request- |
| request-target, the proxy MUST ignore the received Host header field |  | target, the proxy MUST ignore the received Host header field (if any) |
| (if any) and instead replace it with the host information of the |  | and instead replace it with the host information of the request- |
| request-target. If the proxy forwards the request, it MUST generate |  | target. If the proxy forwards the request, it MUST generate a new |
| a new Host field-value based on the received request-target rather |  | Host field-value based on the received request-target rather than |
| than forward the received Host field-value. |  | forward the received Host field-value. |
| Since the Host header field acts as an application-level routing |  | Since the Host header field acts as an application-level routing |
| mechanism, it is a frequent target for malware seeking to poison a |  | mechanism, it is a frequent target for malware seeking to poison a |
| shared cache or redirect a request to an unintended server. An |  | shared cache or redirect a request to an unintended server. An |
| interception proxy is particularly vulnerable if it relies on the |  | interception proxy is particularly vulnerable if it relies on the |
| Host field-value for redirecting requests to internal servers, or for |  | Host field-value for redirecting requests to internal servers, or for |
| use as a cache key in a shared cache, without first verifying that |  | use as a cache key in a shared cache, without first verifying that |
| the intercepted connection is targeting a valid IP address for that |  | the intercepted connection is targeting a valid IP address for that |
| host. |  | host. |
| skipping to change at page 43, line 32 |  | skipping to change at page 41, line 41 |
| context, in order to identify the intended target resource and |  | context, in order to identify the intended target resource and |
| properly service the request. The URI derived from this |  | properly service the request. The URI derived from this |
| reconstruction process is 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 a TLS-secured TCP connection, then |
| then the effective request URI's scheme is "https"; otherwise, the |  | the effective request URI's scheme is "https"; otherwise, the scheme |
| scheme is "http". |  | 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 host name 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 |
| skipping to change at page 44, line 15 |  | skipping to change at page 42, line 24 |
| Example 1: the following message received over an insecure TCP |  | Example 1: the following message received over an insecure TCP |
| connection |  | connection |
| GET /pub/WWW/TheProject.html HTTP/1.1 |  | GET /pub/WWW/TheProject.html HTTP/1.1 |
| Host: www.example.org:8080 |  | Host: www.example.org:8080 |
| has an effective request URI of |  | has an effective request URI of |
| http://www.example.org:8080/pub/WWW/TheProject.html |  | http://www.example.org:8080/pub/WWW/TheProject.html |
| Example 2: the following message received over an SSL/TLS-secured TCP |  | Example 2: the following message received over a TLS-secured TCP |
| connection |  | connection |
| OPTIONS * HTTP/1.1 |  | OPTIONS * HTTP/1.1 |
| Host: www.example.org |  | Host: www.example.org |
| has an effective request URI of |  | has an effective request URI of |
| https://www.example.org |  | https://www.example.org |
| An origin server that does not allow resources to differ by requested |  | An origin server that does not allow resources to differ by requested |
| 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. Message Forwarding |
| As described in Section 2.4, intermediaries can serve a variety of |  | As described in Section 2.3, 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. |
|  |  | Intermediaries that forward a message MUST implement the Connection |
|  |  | header field, as specified in Section 6.1, to exclude fields that are |
|  |  | only intended for the incoming connection. |
| 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 |
| server names, including any aliases, local variations, or literal IP |  | server names, including any aliases, local variations, or literal IP |
| addresses. |  | addresses. |
| If a proxy receives a request-target with a host name that is not a |  | 5.7. Via |
| fully qualified domain name, it MAY add its domain to the host name |  |  |
| it received when forwarding the request. A proxy MUST NOT change the |  |  |
| host name if it is a fully qualified domain name. |  |  |
| A non-transforming proxy MUST NOT rewrite the "path-absolute" and |  | The "Via" header field MUST be sent by a proxy or gateway in |
| "query" parts of the received request-target when forwarding it to |  | forwarded messages to indicate the intermediate protocols and |
| the next inbound server, except as noted above to replace an empty |  | recipients between the user agent and the server on requests, and |
| path with "/" or "*". |  | between the origin server and the client on responses. It is |
|  |  | analogous to the "Received" field used by email systems (Section |
|  |  | 3.6.7 of [RFC5322]). Via is used in HTTP for tracking message |
|  |  | forwards, avoiding request loops, and identifying the protocol |
|  |  | capabilities of all senders along the request/response chain. |
| Intermediaries that forward a message MUST implement the Connection |  | Via = 1#( received-protocol RWS received-by |
| header field as specified in Section 6.1. |  | [ RWS comment ] ) |
|  |  | received-protocol = [ protocol-name "/" ] protocol-version |
|  |  | received-by = ( uri-host [ ":" port ] ) / pseudonym |
|  |  | pseudonym = token |
| 5.6.1. End-to-end and Hop-by-hop Header Fields |  | The received-protocol indicates the protocol version of the message |
|  |  | received by the server or client along each segment of the request/ |
|  |  | response chain. The received-protocol version is appended to the Via |
|  |  | field value when the message is forwarded so that information about |
|  |  | the protocol capabilities of upstream applications remains visible to |
|  |  | all recipients. |
| For the purpose of defining the behavior of caches and non-caching |  | The protocol-name is excluded if and only if it would be "HTTP". The |
| proxies, we divide HTTP header fields into two categories: |  | received-by field is normally the host and optional port number of a |
|  |  | recipient server or client that subsequently forwarded the message. |
|  |  | However, if the real host is considered to be sensitive information, |
|  |  | it MAY be replaced by a pseudonym. If the port is not given, it MAY |
|  |  | be assumed to be the default port of the received-protocol. |
| o End-to-end header fields, which are transmitted to the ultimate |  | Multiple Via field values represent each proxy or gateway that has |
| recipient of a request or response. End-to-end header fields in |  | forwarded the message. Each recipient MUST append its information |
| responses MUST be stored as part of a cache entry and MUST be |  | such that the end result is ordered according to the sequence of |
| transmitted in any response formed from a cache entry. |  | forwarding applications. |
| o Hop-by-hop header fields, which are meaningful only for a single |  | Comments MAY be used in the Via header field to identify the software |
| transport-level connection, and are not stored by caches or |  | of each recipient, analogous to the User-Agent and Server header |
| forwarded by proxies. |  | fields. However, all comments in the Via field are optional and MAY |
|  |  | be removed by any recipient prior to forwarding the message. |
| The following HTTP/1.1 header fields are hop-by-hop header fields: |  | For example, a request message could be sent from an HTTP/1.0 user |
|  |  | agent to an internal proxy code-named "fred", which uses HTTP/1.1 to |
|  |  | forward the request to a public proxy at p.example.net, which |
|  |  | completes the request by forwarding it to the origin server at |
|  |  | www.example.com. The request received by www.example.com would then |
|  |  | have the following Via header field: |
| o Connection |  | Via: 1.0 fred, 1.1 p.example.net (Apache/1.1) |
| o Keep-Alive (Section 19.7.1.1 of [RFC2068]) |  | A proxy or gateway used as a portal through a network firewall SHOULD |
|  |  | NOT forward the names and ports of hosts within the firewall region |
|  |  | unless it is explicitly enabled to do so. If not enabled, the |
|  |  | received-by host of any host behind the firewall SHOULD be replaced |
|  |  | by an appropriate pseudonym for that host. |
| o Proxy-Authenticate (Section 4.2 of [Part7]) |  | A proxy or gateway MAY combine an ordered subsequence of Via header |
|  |  | field entries into a single such entry if the entries have identical |
|  |  | received-protocol values. For example, |
| o Proxy-Authorization (Section 4.3 of [Part7]) |  | Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy |
| o TE |  | could be collapsed to |
| o Trailer |  | Via: 1.0 ricky, 1.1 mertz, 1.0 lucy |
| o Transfer-Encoding |  | Senders SHOULD NOT combine multiple entries unless they are all under |
|  |  | the same organizational control and the hosts have already been |
|  |  | replaced by pseudonyms. Senders MUST NOT combine entries which have |
|  |  | different received-protocol values. |
| o Upgrade |  | 5.8. Message Transforming |
| All other header fields defined by HTTP/1.1 are end-to-end header |  | If a proxy receives a request-target with a host name that is not a |
| fields. |  | fully qualified domain name, it MAY add its own domain to the host |
|  |  | name it received when forwarding the request. A proxy MUST NOT |
|  |  | change the host name if it is a fully qualified domain name. |
| Other hop-by-hop header fields MUST be listed in a Connection header |  | A non-transforming proxy MUST NOT modify the "path-absolute" and |
| field (Section 6.1). |  | "query" parts of the received request-target when forwarding it to |
|  |  | the next inbound server, except as noted above to replace an empty |
|  |  | path with "/" or "*". |
| 5.6.2. Non-modifiable Header Fields |  | A non-transforming proxy MUST preserve the message payload (Section |
|  |  | 3.3 of [Part2]), though it MAY change the message body through |
|  |  | application or removal of a transfer-coding (Section 4). |
| Some features of HTTP/1.1, such as Digest Authentication, depend on |  | A non-transforming proxy SHOULD NOT modify header fields that provide |
| the value of certain end-to-end header fields. A non-transforming |  | information about the end points of the communication chain, the |
| proxy SHOULD NOT modify an end-to-end header field unless the |  | resource state, or the selected representation. |
| 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 (Section 9.5 of [Part2]) |  | o Allow (Section 8.4.1 of [Part2]) |
| o Content-Location (Section 9.8 of [Part2]) |  | o Content-Location (Section 3.1.4.2 of [Part2]) |
| o Content-MD5 (Section 14.15 of [RFC2616]) |  | o Content-MD5 (Section 14.15 of [RFC2616]) |
| o ETag (Section 2.3 of [Part4]) |  | o ETag (Section 2.3 of [Part4]) |
| o Last-Modified (Section 2.2 of [Part4]) |  | o Last-Modified (Section 2.2 of [Part4]) |
| o Server (Section 9.17 of [Part2]) |  | o Server (Section 8.4.2 of [Part2]) |
| A non-transforming proxy MUST NOT modify any of the following fields |  |  |
| in a response: |  |  |
| o Expires (Section 7.3 of [Part6]) |  |  |
| but it MAY add any of these fields if not already present. If an |  | A non-transforming proxy MUST NOT modify an Expires header field |
| Expires header field is added, it MUST be given a field value |  | (Section 7.3 of [Part6]) if already present in a response, but it MAY |
| identical to that of the Date header field in that response. |  | add an Expires header field with a field-value identical to that of |
|  |  | the Date header field. |
| 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: |
| any request: |  |  |
| o Content-Encoding (Section 9.6 of [Part2]) |  | o Content-Encoding (Section 3.1.2.2 of [Part2]) |
| o Content-Range (Section 5.2 of [Part5]) |  | o Content-Range (Section 5.2 of [Part5]) |
| o Content-Type (Section 9.9 of [Part2]) |  | o Content-Type (Section 3.1.1.5 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 7.6 of [Part6]). |  | in the message (see Section 7.5 of [Part6]). |
| Warning: Unnecessary modification of end-to-end header fields |  |  |
| might cause authentication failures if stronger authentication |  |  |
| mechanisms are introduced in later versions of HTTP. Such |  |  |
| authentication mechanisms MAY rely on the values of header fields |  |  |
| not listed here. |  |  |
| A non-transforming proxy MUST preserve the message payload ([Part2]), |  | Warning: Unnecessary modification of header fields might cause |
| though it MAY change the message body through application or removal |  | authentication failures if stronger authentication mechanisms are |
| of a transfer-coding (Section 4). |  | introduced in later versions of HTTP. Such authentication |
|  |  | mechanisms MAY rely on the values of header fields not listed |
|  |  | here. |
| 5.7. Associating a Response to a Request |  | 5.9. 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 4.3 of |  | when one or more informational responses (1xx, see Section 7.2 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 |
|  |  | HTTP messaging is independent of the underlying transport or session- |
|  |  | layer connection protocol(s). HTTP only presumes a reliable |
|  |  | transport with in-order delivery of requests and the corresponding |
|  |  | in-order delivery of responses. The mapping of HTTP request and |
|  |  | response structures onto the data units of an underlying transport |
|  |  | protocol is outside the scope of this specification. |
|  |  | As described in Section 5.2, the specific connection protocols to be |
|  |  | used for an HTTP interaction are determined by client configuration |
|  |  | and the target URI. For example, the "http" URI scheme |
|  |  | (Section 2.7.1) indicates a 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 connection, port, or protocol. |
|  |  | HTTP implementations are expected to engage in connection management, |
|  |  | which includes maintaining the state of current connections, |
|  |  | establishing a new connection or reusing an existing connection, |
|  |  | processing messages received on a connection, detecting connection |
|  |  | failures, and closing each connection. Most clients maintain |
|  |  | multiple connections in parallel, including more than one connection |
|  |  | per server endpoint. Most servers are designed to maintain thousands |
|  |  | of concurrent connections, while controlling request queues to enable |
|  |  | fair use and detect denial of service attacks. |
| 6.1. Connection |  | 6.1. Connection |
| The "Connection" header field allows the sender to specify options |  | The "Connection" header field allows the sender to indicate desired |
| that are desired only for that particular connection. Such |  | control options for the current connection. In order to avoid |
| connection options MUST be removed or replaced before the message can |  | confusing downstream recipients, a proxy or gateway MUST remove or |
| be forwarded downstream by a proxy or gateway. This mechanism also |  | replace any received connection options before forwarding the |
| allows the sender to indicate which HTTP header fields used in the |  | message. |
| message are only intended for the immediate recipient ("hop-by-hop"), |  |  |
| as opposed to all recipients on the chain ("end-to-end"), enabling |  | When a header field is used to supply control information for or |
| the message to be self-descriptive and allowing future connection- |  | about the current connection, the sender SHOULD list the |
| specific extensions to be deployed in HTTP without fear that they |  | corresponding field-name within the "Connection" header field. A |
| will be blindly forwarded by previously deployed intermediaries. |  | proxy or gateway MUST parse a received Connection header field 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 as the |
|  |  | connection-option, and then remove the Connection header field itself |
|  |  | (or replace it with the intermediary's own connection options for the |
|  |  | forwarded message). |
|  |  | Hence, the Connection header field provides a declarative way of |
|  |  | distinguishing header fields that are only intended for the immediate |
|  |  | recipient ("hop-by-hop") from those fields that are intended for all |
|  |  | recipients on the chain ("end-to-end"), enabling the message to be |
|  |  | self-descriptive and allowing future connection-specific extensions |
|  |  | to be deployed without fear that they will be blindly forwarded by |
|  |  | older intermediaries. |
| The Connection header field's value has the following grammar: |  | The Connection header field's value has the following grammar: |
| Connection = 1#connection-option |  | Connection = 1#connection-option |
| connection-option = token |  | connection-option = token |
| Connection options are compared case-insensitively. |  | Connection options are case-insensitive. |
| A proxy or gateway MUST parse a received Connection header field |  |  |
| 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 |  |  |
| as the connection-option, and then remove the Connection header field |  |  |
| itself or replace it with the sender's own connection options for the |  |  |
| 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 7.2 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 |
| skipping to change at page 48, line 38 |  | skipping to change at page 48, line 9 |
| 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 option does not share the same name as an |  | the new connection option does not share the same name as an |
| unrelated header field that might already be deployed. Defining a |  | unrelated header field that might already be deployed. Defining a |
| new connection option essentially reserves that potential field-name |  | new connection option essentially reserves that potential field-name |
| for 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 |  | The "close" connection option is defined for a sender to signal that |
| signal that the connection will be closed after completion of the |  | this connection will be closed after completion of the response. For |
| response. For example, |  | 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 |
| the connection SHOULD NOT be considered "persistent" (Section 6.3) |  | the connection SHOULD be closed after the current request/response is |
| after the current request/response is complete. |  | complete (Section 6.2.5). |
| An HTTP/1.1 client that does not support persistent connections MUST |  |  |
| include the "close" connection option in every request message. |  |  |
| An HTTP/1.1 server that does not support persistent connections MUST |  |  |
| include the "close" connection option in every response message that |  |  |
| does not have a 1xx (Informational) status code. |  |  |
| 6.2. Via |  |  |
| The "Via" header field MUST be sent by a proxy or gateway to indicate |  |  |
| the intermediate protocols and recipients between the user agent and |  |  |
| the server on requests, and between the origin server and the client |  |  |
| on responses. It is analogous to the "Received" field used by email |  |  |
| systems (Section 3.6.7 of [RFC5322]) and is intended to be used for |  |  |
| tracking message forwards, avoiding request loops, and identifying |  |  |
| the protocol capabilities of all senders along the request/response |  |  |
| chain. |  |  |
| Via = 1#( received-protocol RWS received-by |  |  |
| [ RWS comment ] ) |  |  |
| received-protocol = [ protocol-name "/" ] protocol-version |  |  |
| received-by = ( uri-host [ ":" port ] ) / pseudonym |  |  |
| pseudonym = token |  |  |
| The received-protocol indicates the protocol version of the message |  |  |
| received by the server or client along each segment of the request/ |  |  |
| response chain. The received-protocol version is appended to the Via |  |  |
| field value when the message is forwarded so that information about |  |  |
| the protocol capabilities of upstream applications remains visible to |  |  |
| all recipients. |  |  |
| The protocol-name is excluded if and only if it would be "HTTP". The |  |  |
| received-by field is normally the host and optional port number of a |  |  |
| recipient server or client that subsequently forwarded the message. |  |  |
| However, if the real host is considered to be sensitive information, |  |  |
| it MAY be replaced by a pseudonym. If the port is not given, it MAY |  |  |
| be assumed to be the default port of the received-protocol. |  |  |
| Multiple Via field values represent each proxy or gateway that has |  |  |
| forwarded the message. Each recipient MUST append its information |  |  |
| such that the end result is ordered according to the sequence of |  |  |
| forwarding applications. |  |  |
| Comments MAY be used in the Via header field to identify the software |  |  |
| of each recipient, analogous to the User-Agent and Server header |  |  |
| fields. However, all comments in the Via field are optional and MAY |  |  |
| be removed by any recipient prior to forwarding the message. |  |  |
| For example, a request message could be sent from an HTTP/1.0 user |  |  |
| agent to an internal proxy code-named "fred", which uses HTTP/1.1 to |  |  |
| forward the request to a public proxy at p.example.net, which |  |  |
| completes the request by forwarding it to the origin server at |  |  |
| www.example.com. The request received by www.example.com would then |  |  |
| have the following Via header field: |  |  |
| Via: 1.0 fred, 1.1 p.example.net (Apache/1.1) |  |  |
| A proxy or gateway used as a portal through a network firewall SHOULD |  |  |
| NOT forward the names and ports of hosts within the firewall region |  |  |
| unless it is explicitly enabled to do so. If not enabled, the |  |  |
| received-by host of any host behind the firewall SHOULD be replaced |  |  |
| by an appropriate pseudonym for that host. |  |  |
| For organizations that have strong privacy requirements for hiding |  |  |
| internal structures, a proxy or gateway MAY combine an ordered |  |  |
| subsequence of Via header field entries with identical received- |  |  |
| protocol values into a single such entry. For example, |  |  |
| Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy |  |  |
| could be collapsed to |  |  |
| Via: 1.0 ricky, 1.1 mertz, 1.0 lucy |  |  |
| Senders SHOULD NOT combine multiple entries unless they are all under |  | A client that does not support persistent connections MUST send the |
| the same organizational control and the hosts have already been |  | "close" connection option in every request message. |
| replaced by pseudonyms. Senders MUST NOT combine entries which have |  |  |
| different received-protocol values. |  |  |
| 6.3. Persistent Connections |  | A server that does not support persistent connections MUST send the |
|  |  | "close" connection option in every response message that does not |
|  |  | have a 1xx (Informational) status code. |
| 6.3.1. Purpose |  | 6.2. Persistent Connections |
| Prior to persistent connections, a separate TCP connection was |  | HTTP was originally designed to use a separate connection for each |
| established for each request, increasing the load on HTTP servers and |  | request/response pair. As the Web evolved and embedded requests |
| causing congestion on the Internet. The use of inline images and |  | became common for inline images, the connection establishment |
| other associated data often requires a client to make multiple |  | overhead was a significant drain on performance and a concern for |
| requests of the same server in a short amount of time. Analysis of |  | Internet congestion. Message framing (via Content-Length) and |
| these performance problems and results from a prototype |  | optional long-lived connections (via Keep-Alive) were added to |
| implementation are available [Pad1995] [Spe]. Implementation |  | HTTP/1.0 in order to improve performance for some requests. However, |
| experience and measurements of actual HTTP/1.1 implementations show |  | these extensions were insufficient for dynamically generated |
| good results [Nie1997]. Alternatives have also been explored, for |  | responses and difficult to use with intermediaries. |
| example, T/TCP [Tou1998]. |  |  |
| Persistent HTTP connections have a number of advantages: |  | HTTP/1.1 defaults to the use of "persistent connections", which allow |
|  |  | multiple requests and responses to be carried over a single |
|  |  | connection. The "close" connection-option is used to signal that a |
|  |  | connection will close after the current request/response. Persistent |
|  |  | connections have a number of advantages: |
| o By opening and closing fewer TCP connections, CPU time is saved in |  | o By opening and closing fewer connections, CPU time is saved in |
| routers and hosts (clients, servers, proxies, gateways, tunnels, |  | routers and hosts (clients, servers, proxies, gateways, tunnels, |
| or caches), and memory used for TCP protocol control blocks can be |  | or caches), and memory used for protocol control blocks can be |
| saved in hosts. |  | saved in hosts. |
| o HTTP requests and responses can be pipelined on a connection. |  | o Most requests and responses can be pipelined on a connection. |
| Pipelining allows a client to make multiple requests without |  | Pipelining allows a client to make multiple requests without |
| waiting for each response, allowing a single TCP connection to be |  | waiting for each response, allowing a single connection to be used |
| used much more efficiently, with much lower elapsed time. |  | much more efficiently and with less overall latency. |
| o Network congestion is reduced by reducing the number of packets |  | o For TCP connections, network congestion is reduced by eliminating |
| caused by TCP opens, and by allowing TCP sufficient time to |  | the packets associated with the three way handshake and graceful |
| determine the congestion state of the network. |  | close procedures, and by allowing sufficient time to determine the |
|  |  | congestion state of the network. |
| o Latency on subsequent requests is reduced since there is no time |  | o Latency on subsequent requests is reduced since there is no time |
| spent in TCP's connection opening handshake. |  | spent in the connection opening handshake. |
| o HTTP can evolve more gracefully, since errors can be reported |  | o HTTP can evolve more gracefully, since most errors can be reported |
| without the penalty of closing the TCP connection. Clients using |  | without the penalty of closing the connection. Clients using |
| future versions of HTTP might optimistically try a new feature, |  | future versions of HTTP might optimistically try a new feature, |
| but if communicating with an older server, retry with old |  | but if communicating with an older server, retry with old |
| semantics after an error is reported. |  | semantics after an error is reported. |
| HTTP implementations SHOULD implement persistent connections. |  | HTTP implementations SHOULD implement persistent connections. |
| 6.3.2. Overall Operation |  | 6.2.1. Establishment |
| A significant difference between HTTP/1.1 and earlier versions of |  | It is beyond the scope of this specification to describe how |
| HTTP is that persistent connections are the default behavior of any |  | connections are established via various transport or session-layer |
| HTTP connection. That is, unless otherwise indicated, the client |  | protocols. Each connection applies to only one transport link. |
| SHOULD assume that the server will maintain a persistent connection, |  |  |
| even after error responses from the server. |  |  |
| Persistent connections provide a mechanism by which a client and a |  | A recipient determines whether a connection is persistent or not |
| server can signal the close of a TCP connection. This signaling |  | based on the most recently received message's protocol version and |
| takes place using the Connection header field (Section 6.1). Once a |  | Connection header field (if any): |
| close has been signaled, the client MUST NOT send any more requests |  |  |
| on that connection. |  |  |
| 6.3.2.1. Negotiation |  | o If the close connection option is present, the connection will not |
|  |  | persist after the current response; else, |
| An HTTP/1.1 server MAY assume that a HTTP/1.1 client intends to |  | o If the received protocol is HTTP/1.1 (or later), the connection |
| maintain a persistent connection unless a Connection header field |  | will persist after the current response; else, |
| including the connection option "close" was sent in the request. If |  |  |
| the server chooses to close the connection immediately after sending |  |  |
| the response, it SHOULD send a Connection header field including the |  |  |
| connection option "close". |  |  |
| An HTTP/1.1 client MAY expect a connection to remain open, but would |  | o If the received protocol is HTTP/1.0, the "keep-alive" connection |
| decide to keep it open based on whether the response from a server |  | option is present, the recipient is not a proxy, and the recipient |
| contains a Connection header field with the connection option |  | wishes to honor the HTTP/1.0 "keep-alive" mechanism, the |
| "close". In case the client does not want to maintain a connection |  | connection will persist after the current response; otherwise, |
| for more than that request, it SHOULD send a Connection header field |  |  |
| including the connection option "close". |  |  |
| If either the client or the server sends the "close" option in the |  | o The connection will close after the current response. |
| Connection header field, that request becomes the last one for the |  |  |
| connection. |  | A proxy server MUST NOT maintain a persistent connection with an |
|  |  | HTTP/1.0 client (see Section 19.7.1 of [RFC2068] for information and |
|  |  | discussion of the problems with the Keep-Alive header field |
|  |  | implemented by many HTTP/1.0 clients). |
|  |  | 6.2.2. Reuse |
|  |  | In order to remain persistent, all messages on a connection MUST have |
|  |  | a self-defined message length (i.e., one not defined by closure of |
|  |  | the connection), as described in Section 3.3. |
|  |  | A server MAY assume that an HTTP/1.1 client intends to maintain a |
|  |  | persistent connection until a close connection option is received in |
|  |  | a request. |
|  |  | A client MAY reuse a persistent connection until it sends or receives |
|  |  | a close connection option or receives an HTTP/1.0 response without a |
|  |  | "keep-alive" connection option. |
| 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. |  | 6.2.2.1. Pipelining |
| A proxy server MUST NOT establish a HTTP/1.1 persistent connection |  |  |
| with an HTTP/1.0 client (but see Section 19.7.1 of [RFC2068] for |  |  |
| information and discussion of the problems with the Keep-Alive header |  |  |
| field implemented by many HTTP/1.0 clients). |  |  |
| In order to remain persistent, all messages on the connection MUST |  |  |
| have a self-defined message length (i.e., one not defined by closure |  |  |
| of the connection), as described in Section 3.3. |  |  |
| 6.3.2.2. Pipelining |  |  |
| A client that supports persistent connections MAY "pipeline" its |  | A client that supports persistent connections MAY "pipeline" its |
| requests (i.e., send multiple requests without waiting for each |  | requests (i.e., send multiple requests without waiting for each |
| response). A server MUST send its responses to those requests in the |  | response). A server MUST send its responses to those requests in the |
| same order that the requests were received. |  | same order that the requests were received. |
| 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 |
| 2.1.2 of [Part2]). Otherwise, a premature termination of the |  | 5.2.2 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 |  | 6.2.2.2. Retrying Requests |
| Servers will usually have some time-out value beyond which they will |  |  |
| no longer maintain an inactive connection. Proxy servers might make |  |  |
| this a higher value since it is likely that the client will be making |  |  |
| more connections through the same server. The use of persistent |  |  |
| connections places no requirements on the length (or existence) of |  |  |
| this time-out for either the client or the server. |  |  |
| When a client or server wishes to time-out it SHOULD issue a graceful |  |  |
| close on the transport connection. Clients and servers SHOULD both |  |  |
| constantly watch for the other side of the transport close, and |  |  |
| respond to it as appropriate. If a client or server does not detect |  |  |
| the other side's close promptly it could cause unnecessary resource |  |  |
| drain on the network. |  |  |
| A client, server, or proxy MAY close the transport connection at any |  |  |
| time. For example, a client might have started to send a new request |  |  |
| at the same time that the server has decided to close the "idle" |  |  |
| connection. From the server's point of view, the connection is being |  |  |
| closed while it was idle, but from the client's point of view, a |  |  |
| request is in progress. |  |  |
| Clients (including proxies) SHOULD limit the number of simultaneous |  |  |
| connections that they maintain to a given server (including proxies). |  |  |
| Previous revisions of HTTP gave a specific number of connections as a |  |  |
| ceiling, but this was found to be impractical for many applications. |  |  |
| As a result, this specification does not mandate a particular maximum |  |  |
| number of connections, but instead encourages clients to be |  |  |
| conservative when opening multiple connections. |  |  |
| In particular, while using multiple connections avoids the "head-of- |  |  |
| line blocking" problem (whereby a request that takes significant |  |  |
| server-side processing and/or has a large payload can block |  |  |
| subsequent requests on the same connection), each connection used |  |  |
| consumes server resources (sometimes significantly), and furthermore |  |  |
| using multiple connections can cause undesirable side effects in |  |  |
| congested networks. |  |  |
| Note that servers might reject traffic that they deem abusive, |  |  |
| including an excessive number of connections from a client. |  |  |
| 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 2.1.2 of [Part2]). Non-idempotent request methods or |  | Section 5.2.2 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 |  | 6.2.3. Concurrency |
| 6.4.1. Persistent Connections and Flow Control |  |  |
| HTTP/1.1 servers SHOULD maintain persistent connections and use TCP's |  |  |
| flow control mechanisms to resolve temporary overloads, rather than |  |  |
| terminating connections with the expectation that clients will retry. |  |  |
| The latter technique can exacerbate network congestion. |  |  |
| 6.4.2. Monitoring Connections for Error Status Messages |  |  |
| An HTTP/1.1 (or later) client sending a message body SHOULD monitor |  |  |
| the network connection for an error status code while it is |  |  |
| transmitting the request. If the client sees an error status code, |  |  |
| it SHOULD immediately cease transmitting the body. If the body is |  |  |
| being sent using a "chunked" encoding (Section 4), a zero length |  |  |
| 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 |  |  |
| field, the client MUST close the connection. |  |  |
| 6.4.3. Use of the 100 (Continue) Status |  | Clients SHOULD limit the number of simultaneous connections that they |
|  |  | maintain to a given server. |
| The purpose of the 100 (Continue) status code (see Section 4.3.1 of |  | Previous revisions of HTTP gave a specific number of connections as a |
| [Part2]) is to allow a client that is sending a request message with |  | ceiling, but this was found to be impractical for many applications. |
| a request body to determine if the origin server is willing to accept |  | As a result, this specification does not mandate a particular maximum |
| the request (based on the request header fields) before the client |  | number of connections, but instead encourages clients to be |
| sends the request body. In some cases, it might either be |  | conservative when opening multiple connections. |
| inappropriate or highly inefficient for the client to send the body |  |  |
| if the server will reject the message without looking at the body. |  |  |
| Requirements for HTTP/1.1 clients: |  | Multiple connections are typically used to avoid the "head-of-line |
|  |  | blocking" problem, wherein a request that takes significant server- |
|  |  | side processing and/or has a large payload blocks subsequent requests |
|  |  | on the same connection. However, each connection consumes server |
|  |  | resources. Furthermore, using multiple connections can cause |
|  |  | undesirable side effects in congested networks. |
| o If a client will wait for a 100 (Continue) response before sending |  | Note that servers might reject traffic that they deem abusive, |
| the request body, it MUST send an Expect header field (Section |  | including an excessive number of connections from a client. |
| 9.11 of [Part2]) with the "100-continue" expectation. |  |  |
| o A client MUST NOT send an Expect header field with the "100- |  | 6.2.4. Failures and Time-outs |
| continue" expectation if it does not intend to send a request |  |  |
| body. |  |  |
| Because of the presence of older implementations, the protocol allows |  | Servers will usually have some time-out value beyond which they will |
| ambiguous situations in which a client might send "Expect: 100- |  | no longer maintain an inactive connection. Proxy servers might make |
| continue" without receiving either a 417 (Expectation Failed) or a |  | this a higher value since it is likely that the client will be making |
| 100 (Continue) status code. Therefore, when a client sends this |  | more connections through the same server. The use of persistent |
| header field to an origin server (possibly via a proxy) from which it |  | connections places no requirements on the length (or existence) of |
| has never seen a 100 (Continue) status code, the client SHOULD NOT |  | this time-out for either the client or the server. |
| wait for an indefinite period before sending the request body. |  |  |
| Requirements for HTTP/1.1 origin servers: |  | When a client or server wishes to time-out it SHOULD issue a graceful |
|  |  | close on the transport connection. Clients and servers SHOULD both |
|  |  | constantly watch for the other side of the transport close, and |
|  |  | respond to it as appropriate. If a client or server does not detect |
|  |  | the other side's close promptly it could cause unnecessary resource |
|  |  | drain on the network. |
| o Upon receiving a request which includes an Expect header field |  | A client, server, or proxy MAY close the transport connection at any |
| with the "100-continue" expectation, an origin server MUST either |  | time. For example, a client might have started to send a new request |
| respond with 100 (Continue) status code and continue to read from |  | at the same time that the server has decided to close the "idle" |
| the input stream, or respond with a final status code. The origin |  | connection. From the server's point of view, the connection is being |
| server MUST NOT wait for the request body before sending the 100 |  | closed while it was idle, but from the client's point of view, a |
| (Continue) response. If it responds with a final status code, it |  | request is in progress. |
| MAY close the transport connection or it MAY continue to read and |  |  |
| discard the rest of the request. It MUST NOT perform the request |  |  |
| method if it returns a final status code. |  |  |
| o An origin server SHOULD NOT send a 100 (Continue) response if the |  | Servers SHOULD maintain persistent connections and allow the |
| request message does not include an Expect header field with the |  | underlying transport's flow control mechanisms to resolve temporary |
| "100-continue" expectation, and MUST NOT send a 100 (Continue) |  | overloads, rather than terminate connections with the expectation |
| response if such a request comes from an HTTP/1.0 (or earlier) |  | that clients will retry. The latter technique can exacerbate network |
| client. There is an exception to this rule: for compatibility |  | congestion. |
| with [RFC2068], a server MAY send a 100 (Continue) status code in |  |  |
| response to an HTTP/1.1 PUT or POST request that does not include |  |  |
| an Expect header field with the "100-continue" expectation. This |  |  |
| exception, the purpose of which is to minimize any client |  |  |
| processing delays associated with an undeclared wait for 100 |  |  |
| (Continue) status code, applies only to HTTP/1.1 requests, and not |  |  |
| to requests with any other HTTP-version value. |  |  |
| o An origin server MAY omit a 100 (Continue) response if it has |  | A client sending a message body SHOULD monitor the network connection |
| already received some or all of the request body for the |  | for an error status code while it is transmitting the request. If |
| corresponding request. |  | the client sees an error status code, it SHOULD immediately cease |
|  |  | transmitting the body and close the connection. |
| o An origin server that sends a 100 (Continue) response MUST |  | 6.2.5. Tear-down |
| ultimately send a final status code, once the request body is |  |  |
| received and processed, unless it terminates the transport |  |  |
| connection prematurely. |  |  |
| o If an origin server receives a request that does not include an |  | The Connection header field (Section 6.1) provides a "close" |
| Expect header field with the "100-continue" expectation, the |  | connection option that a sender SHOULD send when it wishes to close |
| request includes a request body, and the server responds with a |  | the connection after the current request/response pair. |
| final status code before reading the entire request body from the |  |  |
| transport connection, then the server SHOULD NOT close the |  |  |
| transport connection until it has read the entire request, or |  |  |
| until the client closes the connection. Otherwise, the client |  |  |
| might not reliably receive the response message. However, this |  |  |
| requirement ought not be construed as preventing a server from |  |  |
| defending itself against denial-of-service attacks, or from badly |  |  |
| broken client implementations. |  |  |
| Requirements for HTTP/1.1 proxies: |  | A client that sends a close connection option MUST NOT send further |
|  |  | requests on that connection (after the one containing close) and MUST |
|  |  | close the connection after reading the final response message |
|  |  | corresponding to this request. |
| o If a proxy receives a request that includes an Expect header field |  | A server that receives a close connection option MUST initiate a |
| with the "100-continue" expectation, and the proxy either knows |  | lingering close of the connection after it sends the final response |
| that the next-hop server complies with HTTP/1.1 or higher, or does |  | to the request that contained close. The server SHOULD include a |
| not know the HTTP version of the next-hop server, it MUST forward |  | close connection option in its final response on that connection. |
| the request, including the Expect header field. |  | The server MUST NOT process any further requests received on that |
|  |  | connection. |
| o If the proxy knows that the version of the next-hop server is |  | A server that sends a close connection option MUST initiate a |
| HTTP/1.0 or lower, it MUST NOT forward the request, and it MUST |  | lingering close of the connection after it sends the response |
| respond with a 417 (Expectation Failed) status code. |  | containing close. The server MUST NOT process any further requests |
|  |  | received on that connection. |
| o Proxies SHOULD maintain a record of the HTTP version numbers |  | A client that receives a close connection option MUST cease sending |
| received from recently-referenced next-hop servers. |  | requests on that connection and close the connection after reading |
|  |  | the response message containing the close; if additional pipelined |
|  |  | requests had been sent on the connection, the client SHOULD assume |
|  |  | that they will not be processed by the server. |
| o A proxy MUST NOT forward a 100 (Continue) response if the request |  | If a server performs an immediate close of a TCP connection, there is |
| message was received from an HTTP/1.0 (or earlier) client and did |  | a significant risk that the client will not be able to read the last |
| not include an Expect header field with the "100-continue" |  | HTTP response. If the server receives additional data from the |
| expectation. This requirement overrides the general rule for |  | client on a fully-closed connection, such as another request that was |
| forwarding of 1xx responses (see Section 4.3 of [Part2]). |  | sent by the client before receiving the server's response, the |
|  |  | server's TCP stack will send a reset packet to the client; |
|  |  | unfortunately, the reset packet might erase the client's |
|  |  | unacknowledged input buffers before they can be read and interpreted |
|  |  | by the client's HTTP parser. |
| 6.4.4. Closing Connections on Error |  | To avoid the TCP reset problem, a server can perform a lingering |
|  |  | close on a connection by closing only the write side of the read/ |
|  |  | write connection (a half-close) and continuing to read from the |
|  |  | connection until the connection is closed by the client or the server |
|  |  | is reasonably certain that its own TCP stack has received the |
|  |  | client's acknowledgement of the packet(s) containing the server's |
|  |  | last response. It is then safe for the server to fully close the |
|  |  | connection. |
| If the client is sending data, a server implementation using TCP |  | It is unknown whether the reset problem is exclusive to TCP or might |
| SHOULD be careful to ensure that the client acknowledges receipt of |  | also be found in other transport connection protocols. |
| the packet(s) containing the response, before the server closes the |  |  |
| 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 |  |  |
| the client, which might erase the client's unacknowledged input |  |  |
| buffers before they can be read and interpreted by the HTTP |  |  |
| application. |  |  |
| 6.5. Upgrade |  | 6.3. Upgrade |
| The "Upgrade" header field allows the client to specify what |  | The "Upgrade" header field is intended to provide a simple mechanism |
| additional communication protocols it would like to use, if the |  | for transitioning from HTTP/1.1 to some other protocol on the same |
| server chooses to switch protocols. Servers can use it to indicate |  | connection. A client MAY send a list of protocols in the Upgrade |
| what protocols they are willing to switch to. |  | header field of a request to invite the server to switch to one or |
|  |  | more of those protocols before sending the final response. A server |
|  |  | MUST send an Upgrade header field in 101 (Switching Protocols) |
|  |  | responses to indicate which protocol(s) are being switched to, and |
|  |  | MUST send it in 426 (Upgrade Required) responses to indicate |
|  |  | acceptable protocols. A server MAY send an Upgrade header field in |
|  |  | any other response to indicate that they might be willing to upgrade |
|  |  | to one of the specified protocols for a future request. |
| Upgrade = 1#protocol |  | Upgrade = 1#protocol |
| protocol = protocol-name ["/" protocol-version] |  | protocol = protocol-name ["/" protocol-version] |
| protocol-name = token |  | protocol-name = token |
| protocol-version = token |  | protocol-version = token |
| For example, |  | For example, |
| Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11 |  | Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11 |
| The Upgrade header field is intended to provide a simple mechanism |  | Upgrade eases the difficult transition between incompatible protocols |
| for transitioning from HTTP/1.1 to some other, incompatible protocol. |  | by allowing the client to initiate a request in the more commonly |
| It does so by allowing the client to advertise its desire to use |  | supported protocol while indicating to the server that it would like |
| another protocol, such as a later version of HTTP with a higher major |  | to use a "better" protocol if available (where "better" is determined |
| version number, even though the current request has been made using |  | by the server, possibly according to the nature of the request method |
| HTTP/1.1. This eases the difficult transition between incompatible |  | or target resource). |
| protocols by allowing the client to initiate a request in the more |  |  |
| commonly supported protocol while indicating to the server that it |  |  |
| would like to use a "better" protocol if available (where "better" is |  |  |
| determined by the server, possibly according to the nature of the |  |  |
| request method or target resource). |  |  |
| The Upgrade header field only applies to switching application-layer |  | Upgrade cannot be used to insist on a protocol change; its acceptance |
| protocols upon the existing transport-layer connection. Upgrade |  | and use by the server is optional. The capabilities and nature of |
| cannot be used to insist on a protocol change; its acceptance and use |  | the application-level communication after the protocol change is |
| by the server is optional. The capabilities and nature of the |  | entirely dependent upon the new protocol chosen, although the first |
| application-layer communication after the protocol change is entirely |  | action after changing the protocol MUST be a response to the initial |
| dependent upon the new protocol chosen, although the first action |  | HTTP request that contained the Upgrade header field. |
| after changing the protocol MUST be a response to the initial HTTP |  |  |
| request containing the Upgrade header field. |  |  |
| The Upgrade header field only applies to the immediate connection. |  | For example, if the Upgrade header field is received in a GET request |
| Therefore, the upgrade keyword MUST be supplied within a Connection |  | and the server decides to switch protocols, then it MUST first |
| header field (Section 6.1) whenever Upgrade is present in an HTTP/1.1 |  | respond with a 101 (Switching Protocols) message in HTTP/1.1 and then |
| message. |  | immediately follow that with the new protocol's equivalent of a |
|  |  | response to a GET on the target resource. This allows a connection |
|  |  | to be upgraded to protocols with the same semantics as HTTP without |
|  |  | the latency cost of an additional round-trip. A server MUST NOT |
|  |  | switch protocols unless the received message semantics can be honored |
|  |  | by the new protocol; an OPTIONS request can be honored by any |
|  |  | protocol. |
| The Upgrade header field cannot be used to indicate a switch to a |  | When Upgrade is sent, a sender MUST also send a Connection header |
| protocol on a different connection. For that purpose, it is more |  | field (Section 6.1) that contains the "upgrade" connection option, in |
| appropriate to use a 3xx (Redirection) response (Section 4.5 of |  | order to prevent Upgrade from being accidentally forwarded by |
| [Part2]). |  | intermediaries that might not implement the listed protocols. A |
|  |  | server MUST ignore an Upgrade header field that is received in an |
|  |  | HTTP/1.0 request. |
| Servers MUST include the "Upgrade" header field in 101 (Switching |  | The Upgrade header field only applies to switching application-level |
| Protocols) responses to indicate which protocol(s) are being switched |  | protocols on the existing connection; it cannot be used to switch to |
| to, and MUST include it in 426 (Upgrade Required) responses to |  | a protocol on a different connection. For that purpose, it is more |
| indicate acceptable protocols to upgrade to. Servers MAY include it |  | appropriate to use a 3xx (Redirection) response (Section 7.4 of |
| in any other response to indicate that they are willing to upgrade to |  | [Part2]). |
| 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 2.7 and future updates to this |  | version rules of Section 2.6 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>. |
| skipping to change at page 58, line 30 |  | skipping to change at page 55, line 14 |
| associated registry entries shall be updated according to the |  | associated registry entries shall be updated according to the |
| permanent registrations below: |  | permanent registrations below: |
| +-------------------+----------+----------+---------------+ |  | +-------------------+----------+----------+---------------+ |
| | Header Field Name | Protocol | Status | Reference | |  | | Header Field Name | Protocol | Status | Reference | |
| +-------------------+----------+----------+---------------+ |  | +-------------------+----------+----------+---------------+ |
| | Connection | http | standard | Section 6.1 | |  | | Connection | http | standard | Section 6.1 | |
| | Content-Length | http | standard | Section 3.3.2 | |  | | Content-Length | http | standard | Section 3.3.2 | |
| | Host | http | standard | Section 5.4 | |  | | Host | http | standard | Section 5.4 | |
| | TE | http | standard | Section 4.3 | |  | | TE | http | standard | Section 4.3 | |
| | Trailer | http | standard | Section 4.4 | |  | | Trailer | http | standard | Section 4.1.1 | |
| | Transfer-Encoding | http | standard | Section 3.3.1 | |  | | Transfer-Encoding | http | standard | Section 3.3.1 | |
| | Upgrade | http | standard | Section 6.5 | |  | | Upgrade | http | standard | Section 6.3 | |
| | Via | http | standard | Section 6.2 | |  | | Via | http | standard | Section 5.7 | |
| +-------------------+----------+----------+---------------+ |  | +-------------------+----------+----------+---------------+ |
| Furthermore, the header field-name "Close" shall be registered as |  | Furthermore, the header field-name "Close" shall be registered as |
| "reserved", since using that name as an HTTP header field might |  | "reserved", since using that name as an HTTP header field might |
| conflict with the "close" connection option of the "Connection" |  | conflict with the "close" connection option of the "Connection" |
| header field (Section 6.1). |  | header field (Section 6.1). |
| +-------------------+----------+----------+-------------+ |  | +-------------------+----------+----------+-------------+ |
| | Header Field Name | Protocol | Status | Reference | |  | | Header Field Name | Protocol | Status | Reference | |
| +-------------------+----------+----------+-------------+ |  | +-------------------+----------+----------+-------------+ |
| skipping to change at page 59, line 17 |  | skipping to change at page 55, line 46 |
| 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 2.8.1 | |  | | http | Hypertext Transfer Protocol | Section 2.7.1 | |
| | https | Hypertext Transfer Protocol Secure | Section 2.8.2 | |  | | https | Hypertext Transfer Protocol Secure | Section 2.7.2 | |
| +------------+------------------------------------+---------------+ |  | +------------+------------------------------------+---------------+ |
| 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 |
| skipping to change at page 61, line 52 |  | skipping to change at page 58, line 34 |
| 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 5.4 of [Part2]) unless the encoding transformation |  | codings (Section 3.1.2.1 of [Part2]) unless the encoding |
| is identical, as it is the case for the compression codings defined |  | transformation is identical, as is the case for the compression |
| in Section 4.2. |  | codings defined 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. Use of program names for |
|  |  | the identification of encoding formats is not desirable and is |
|  |  | discouraged for future encodings. |
| 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>. |
| 7.5. Transfer Coding Registrations |  | 7.5. Transfer Coding Registrations |
| The HTTP Transfer Coding Registry shall be updated with the |  | The HTTP Transfer Coding Registry shall be updated with the |
| registrations below: |  | registrations below: |
| +----------+----------------------------------------+---------------+ |  | +----------+----------------------------------------+---------------+ |
| skipping to change at page 63, line 28 |  | skipping to change at page 60, line 14 |
| 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 2.7 | |  | | HTTP | Hypertext Transfer | any DIGIT.DIGIT | Section 2.6 | |
| | | 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 |
| described by this document. The discussion does not include |  | described by this document. The discussion does not include |
| definitive solutions to the problems revealed, though it does make |  | definitive solutions to the problems revealed, though it does make |
| some suggestions for reducing security risks. |  | some suggestions for reducing security risks. |
| 8.1. 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 |
| (e.g., the user's name, location, mail address, passwords, encryption |  | information, including both information provided by the user to |
| keys, etc.), and SHOULD be very careful to prevent unintentional |  | interact with resources (e.g., the user's name, location, mail |
| leakage of this information. We very strongly recommend that a |  | address, passwords, encryption keys, etc.) and information about the |
| convenient interface be provided for the user to control |  | user's browsing activity over time (e.g., history, bookmarks, etc.). |
| dissemination of such information, and that designers and |  | HTTP implementations need to prevent unintentional leakage of this |
| implementers be particularly careful in this area. History shows |  | information. |
| that errors in this area often create serious security and/or privacy |  |  |
| problems and generate highly adverse publicity for the implementer's |  |  |
| 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. |
| HTTP log information is confidential in nature; its handling is often |  | HTTP log information is confidential in nature; its handling is often |
| skipping to change at page 64, line 32 |  | skipping to change at page 61, line 15 |
| client should not be published even if the key is pseudonymous. |  | client should not be published even if the key is pseudonymous. |
| To minimize the risk of theft or accidental publication, log |  | To minimize the risk of theft or accidental publication, log |
| information should be purged of personally identifiable information, |  | information should be purged of personally identifiable information, |
| including user identifiers, IP addresses, and user-provided query |  | including user identifiers, IP addresses, and user-provided query |
| parameters, as soon as that information is no longer necessary to |  | parameters, as soon as that information is no longer necessary to |
| support operational needs for security, auditing, or fraud control. |  | support operational needs for security, auditing, or fraud control. |
| 8.3. Attacks Based On File and Path Names |  | 8.3. Attacks Based On File and Path Names |
| Implementations of HTTP origin servers SHOULD be careful to restrict |  | Origin servers SHOULD be careful to restrict the documents returned |
| the documents returned by HTTP requests to be only those that were |  | by HTTP requests to be only those that were intended by the server |
| intended by the server administrators. If an HTTP server translates |  | administrators. If an HTTP server translates HTTP URIs directly into |
| HTTP URIs directly into file system calls, the server MUST take |  | file system calls, the server MUST take special care not to serve |
| special care not to serve files that were not intended to be |  | files that were not intended to be delivered to HTTP clients. For |
| delivered to HTTP clients. For example, UNIX, Microsoft Windows, and |  | example, UNIX, Microsoft Windows, and other operating systems use |
| other operating systems use ".." as a path component to indicate a |  | ".." as a path component to indicate a directory level above the |
| directory level above the current one. On such a system, an HTTP |  | current one. On such a system, an HTTP server MUST disallow any such |
| server MUST disallow any such construct in the request-target if it |  | construct in the request-target if it would otherwise allow access to |
| would otherwise allow access to a resource outside those intended to |  | a resource outside those intended to be accessible via the HTTP |
| be accessible via the HTTP server. Similarly, files intended for |  | server. Similarly, files intended for reference only internally to |
| reference only internally to the server (such as access control |  | the server (such as access control files, configuration files, and |
| files, configuration files, and script code) MUST be protected from |  | script code) MUST be protected from inappropriate retrieval, since |
| inappropriate retrieval, since they might contain sensitive |  | they might contain sensitive information. |
| information. Experience has shown that minor bugs in such HTTP |  |  |
| server implementations have turned into security risks. |  |  |
| 8.4. DNS-related Attacks |  | 8.4. DNS-related Attacks |
| HTTP clients rely heavily on the Domain Name Service (DNS), and are |  | HTTP clients rely heavily on the Domain Name Service (DNS), and are |
| thus generally prone to security attacks based on the deliberate |  | thus generally prone to security attacks based on the deliberate |
| misassociation of IP addresses and DNS names not protected by DNSSec. |  | misassociation of IP addresses and DNS names not protected by DNSSec. |
| Clients need to be cautious in assuming the validity of an IP number/ |  | Clients need to be cautious in assuming the validity of an IP number/ |
| DNS name association unless the response is protected by DNSSec |  | DNS name association unless the response is protected by DNSSec |
| ([RFC4033]). |  | ([RFC4033]). |
| skipping to change at page 65, line 38 |  | skipping to change at page 62, line 16 |
| to cache poisoning attacks. |  | to cache poisoning attacks. |
| Implementers 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 |  |  |
| protect against a broad range of security and privacy attacks. Such |  |  |
| cryptography is beyond the scope of the HTTP/1.1 specification. |  |  |
| 8.6. Protocol Element Size Overflows |  | 8.6. Protocol Element Size Overflows |
| Because HTTP uses mostly textual, character-delimited fields, |  | Because HTTP uses mostly textual, character-delimited fields, |
| attackers can overflow buffers in implementations, and/or perform a |  | attackers can overflow buffers in implementations, and/or perform a |
| Denial of Service against implementations that accept fields with |  | Denial of Service against implementations that accept fields with |
| 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 4.6.12 of |  | that have request-targets that are too long (Section 7.5.12 of |
| [Part2]) or request entities that are too large (Section 4.6 of |  | [Part2]) or request entities that are too large (Section 7.5 of |
| [Part2]). |  | [Part2]). |
| Other fields (including but not limited to request methods, response |  | Recipients SHOULD carefully limit the extent to which they read other |
| status phrases, header field-names, and body chunks) SHOULD be |  | fields, including (but not limited to) request methods, response |
| limited by implementations carefully, so as to not impede |  | status phrases, header field-names, and body chunks, so as to avoid |
| interoperability. |  | denial of service attacks without impeding 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 |
| RFC 1945, RFC 2068, RFC 2145, and RFC 2616, including substantial |  | RFC 1945, RFC 2068, RFC 2145, and RFC 2616, including substantial |
| 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 W. de |  | Adam Barth, Adam Roach, Addison Phillips, Adrian Chadd, Adrien W. de |
| Croy, Alan Ford, Alan Ruttenberg, Albert Lunde, Alek Storm, Alex |  | Croy, Alan Ford, Alan Ruttenberg, Albert Lunde, Alek Storm, Alex |
| Rousskov, Alexandre Morgaut, Alexey Melnikov, Alisha Smith, Amichai |  | Rousskov, Alexandre Morgaut, Alexey Melnikov, Alisha Smith, Amichai |
| Rothman, Amit Klein, Amos Jeffries, Andreas Maier, Andreas Petersson, |  | Rothman, Amit Klein, Amos Jeffries, Andreas Maier, Andreas Petersson, |
| Anne van Kesteren, Anthony Bryan, Asbjorn Ulsberg, Balachander |  | Anil Sharma, Anne van Kesteren, Anthony Bryan, Asbjorn Ulsberg, |
| Krishnamurthy, Barry Leiba, Ben Laurie, Benjamin Niven-Jenkins, Bil |  | Balachander Krishnamurthy, Barry Leiba, Ben Laurie, Benjamin Niven- |
| Corry, Bill Burke, Bjoern Hoehrmann, Bob Scheifler, Boris Zbarsky, |  | Jenkins, Bil Corry, Bill Burke, Bjoern Hoehrmann, Bob Scheifler, |
| Brett Slatkin, Brian Kell, Brian McBarron, Brian Pane, Brian Smith, |  | Boris Zbarsky, Brett Slatkin, Brian Kell, Brian McBarron, Brian Pane, |
| Bryce Nesbitt, Cameron Heavon-Jones, Carl Kugler, Carsten Bormann, |  | Brian Smith, Bryce Nesbitt, Cameron Heavon-Jones, Carl Kugler, |
| Charles Fry, Chris Newman, Cyrus Daboo, Dale Robert Anderson, Dan |  | Carsten Bormann, Charles Fry, Chris Newman, Cyrus Daboo, Dale Robert |
| Winship, Daniel Stenberg, Dave Cridland, Dave Crocker, Dave Kristol, |  | Anderson, Dan Wing, Dan Winship, Daniel Stenberg, Dave Cridland, Dave |
| David Booth, David Singer, David W. Morris, Diwakar Shetty, Dmitry |  | Crocker, Dave Kristol, David Booth, David Singer, David W. Morris, |
| Kurochkin, Drummond Reed, Duane Wessels, Edward Lee, Eliot Lear, Eran |  | Diwakar Shetty, Dmitry Kurochkin, Drummond Reed, Duane Wessels, |
| Hammer-Lahav, Eric D. Williams, Eric J. Bowman, Eric Lawrence, Eric |  | Edward Lee, Eliot Lear, Eran Hammer-Lahav, Eric D. Williams, Eric J. |
| Rescorla, Erik Aronesty, Florian Weimer, Frank Ellermann, Fred Bohle, |  | Bowman, Eric Lawrence, Eric Rescorla, Erik Aronesty, Evan Prodromou, |
| Geoffrey Sneddon, Gervase Markham, Greg Wilkins, Harald Tveit |  | Florian Weimer, Frank Ellermann, Fred Bohle, Gabriel Montenegro, |
| Alvestrand, Harry Halpin, Helge Hess, Henrik Nordstrom, Henry S. |  | Geoffrey Sneddon, Gervase Markham, Grahame Grieve, Greg Wilkins, |
| Thompson, Henry Story, Herbert van de Sompel, Howard Melman, Hugo |  | Harald Tveit Alvestrand, Harry Halpin, Helge Hess, Henrik Nordstrom, |
| Haas, Ian Hickson, Ingo Struck, J. Ross Nicoll, James H. Manger, |  | Henry S. Thompson, Henry Story, Herbert van de Sompel, Howard Melman, |
| James Lacey, James M. Snell, Jamie Lokier, Jan Algermissen, Jeff |  | Hugo Haas, Ian Fette, Ian Hickson, Ido Safruti, Ingo Struck, J. Ross |
| Hodges (who came up with the term 'effective Request-URI'), Jeff |  | Nicoll, James H. Manger, James Lacey, James M. Snell, Jamie Lokier, |
| Walden, Jim Luther, Joe D. Williams, Joe Gregorio, Joe Orton, John C. |  | Jan Algermissen, Jeff Hodges (who came up with the term 'effective |
| Klensin, John C. Mallery, John Cowan, John Kemp, John Panzer, John |  | Request-URI'), Jeff Walden, Jim Luther, Joe D. Williams, Joe |
| Schneider, John Stracke, John Sullivan, Jonas Sicking, Jonathan |  | Gregorio, Joe Orton, John C. Klensin, John C. Mallery, John Cowan, |
| Billington, Jonathan Moore, Jonathan Rees, Jonathan Silvera, Jordi |  | John Kemp, John Panzer, John Schneider, John Stracke, John Sullivan, |
| Ros, Joris Dobbelsteen, Josh Cohen, Julien Pierre, Jungshik Shin, |  | Jonas Sicking, Jonathan Billington, Jonathan Moore, Jonathan Rees, |
| Justin Chapweske, Justin Erenkrantz, Justin James, Kalvinder Singh, |  | Jonathan Silvera, Jordi Ros, Joris Dobbelsteen, Josh Cohen, Julien |
| Karl Dubost, Keith Hoffman, Keith Moore, Koen Holtman, Konstantin |  | Pierre, Jungshik Shin, Justin Chapweske, Justin Erenkrantz, Justin |
| Voronkov, Kris Zyp, Lisa Dusseault, Maciej Stachowiak, Marc |  | James, Kalvinder Singh, Karl Dubost, Keith Hoffman, Keith Moore, Koen |
| Schneider, Marc Slemko, Mark Baker, Mark Pauley, Mark Watson, Markus |  | Holtman, Konstantin Voronkov, Kris Zyp, Lisa Dusseault, Maciej |
| Isomaki, Markus Lanthaler, Martin J. Duerst, Martin Musatov, Martin |  | Stachowiak, Marc Schneider, Marc Slemko, Mark Baker, Mark Pauley, |
| Nilsson, Martin Thomson, Matt Lynch, Matthew Cox, Max Clark, Michael |  | Mark Watson, Markus Isomaki, Markus Lanthaler, Martin J. Duerst, |
| Burrows, Michael Hausenblas, Mike Amundsen, Mike Belshe, Mike Kelly, |  | Martin Musatov, Martin Nilsson, Martin Thomson, Matt Lynch, Matthew |
| Mike Schinkel, Miles Sabin, Murray S. Kucherawy, Mykyta Yevstifeyev, |  | Cox, Max Clark, Michael Burrows, Michael Hausenblas, Mike Amundsen, |
| Nathan Rixham, Nicholas Shanks, Nico Williams, Nicolas Alvarez, |  | Mike Belshe, Mike Kelly, Mike Schinkel, Miles Sabin, Murray S. |
| Nicolas Mailhot, Noah Slater, Pablo Castro, Pat Hayes, Patrick R. |  | Kucherawy, Mykyta Yevstifeyev, Nathan Rixham, Nicholas Shanks, Nico |
| McManus, Paul E. Jones, Paul Hoffman, Paul Marquess, Peter Lepeska, |  | Williams, Nicolas Alvarez, Nicolas Mailhot, Noah Slater, Pablo |
| Peter Saint-Andre, Peter Watkins, Phil Archer, Phillip Hallam-Baker, |  | Castro, Pat Hayes, Patrick R. McManus, Paul E. Jones, Paul Hoffman, |
| Poul-Henning Kamp, Preethi Natarajan, Ray Polk, Reto Bachmann-Gmuer, |  | Paul Marquess, Peter Lepeska, Peter Saint-Andre, Peter Watkins, Phil |
|  |  | Archer, Philippe Mougin, Phillip Hallam-Baker, Poul-Henning Kamp, |
|  |  | Preethi Natarajan, Rajeev Bector, Ray Polk, Reto Bachmann-Gmuer, |
| Richard Cyganiak, Robert Brewer, Robert Collins, Robert O'Callahan, |  | Richard Cyganiak, Robert Brewer, Robert Collins, Robert O'Callahan, |
| Robert Olofsson, Robert Sayre, Robert Siemer, Robert de Wilde, |  | Robert Olofsson, Robert Sayre, Robert Siemer, Robert de Wilde, |
| Roberto Javier Godoy, Roberto Peon, Ronny Widjaja, S. Mike Dierken, |  | Roberto Javier Godoy, Roberto Peon, Ronny Widjaja, S. Mike Dierken, |
| Salvatore Loreto, Sam Johnston, Sam Ruby, Scott Lawrence (who |  | Salvatore Loreto, Sam Johnston, Sam Ruby, Scott Lawrence (who |
| maintained the original issues list), Sean B. Palmer, Shane McCarron, |  | maintained the original issues list), Sean B. Palmer, Shane McCarron, |
| Stefan Eissing, Stefan Tilkov, Stefanos Harhalakis, Stephane |  | Stefan Eissing, Stefan Tilkov, Stefanos Harhalakis, Stephane |
| Bortzmeyer, Stephen Farrell, Stephen Ludin, Stuart Williams, Subbu |  | Bortzmeyer, Stephen Farrell, Stephen Ludin, Stuart Williams, Subbu |
| Allamaraju, Sylvain Hellegouarch, Tapan Divekar, Tatsuya Hayashi, Ted |  | Allamaraju, Sylvain Hellegouarch, Tapan Divekar, Tatsuya Hayashi, Ted |
| Hardie, Thomas Broyer, Thomas Nordin, Thomas Roessler, Tim Bray, Tim |  | Hardie, Thomas Broyer, Thomas Nordin, Thomas Roessler, Tim Bray, Tim |
| Morgan, Tim Olsen, Tom Zhou, Travis Snoozy, Tyler Close, Vincent |  | Morgan, Tim Olsen, Tom Zhou, Travis Snoozy, Tyler Close, Vincent |
| Murphy, Wenbo Zhu, Werner Baumann, Wilbur Streett, Wilfredo Sanchez |  | Murphy, Wenbo Zhu, Werner Baumann, Wilbur Streett, Wilfredo Sanchez |
| Vega, William A. Rowe Jr., William Chan, Willy Tarreau, Xiaoshu Wang, |  | Vega, William A. Rowe Jr., William Chan, Willy Tarreau, Xiaoshu Wang, |
| Yaron Goland, Yngve Nysaeter Pettersen, Yoav Nir, Yogesh Bang, Yutaka |  | Yaron Goland, Yngve Nysaeter Pettersen, Yoav Nir, Yogesh Bang, Yutaka |
| Oiwa, Zed A. Shaw, and Zhong Yu. |  | Oiwa, Yves Lafon (long-time member of the editor team), Zed A. Shaw, |
|  |  | and Zhong Yu. |
| 10. References |  | 10. References |
| 10.1. Normative References |  | 10.1. Normative References |
| [Part2] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., |  | [Part2] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext |
| "HTTP/1.1, part 2: Semantics and Payloads", |  | Transfer Protocol (HTTP/1.1): Semantics and Content", |
| draft-ietf-httpbis-p2-semantics-20 (work in progress), |  | draft-ietf-httpbis-p2-semantics-21 (work in progress), |
| July 2012. |  | October 2012. |
| [Part4] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., |  | [Part4] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext |
| "HTTP/1.1, part 4: Conditional Requests", |  | Transfer Protocol (HTTP/1.1): Conditional Requests", |
| draft-ietf-httpbis-p4-conditional-20 (work in |  | draft-ietf-httpbis-p4-conditional-21 (work in |
| progress), July 2012. |  | progress), October 2012. |
| [Part5] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., |  | [Part5] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., |
| "HTTP/1.1, part 5: Range Requests", |  | "Hypertext Transfer Protocol (HTTP/1.1): Range |
| draft-ietf-httpbis-p5-range-20 (work in progress), |  | Requests", draft-ietf-httpbis-p5-range-21 (work in |
| July 2012. |  | progress), October 2012. |
| [Part6] Fielding, R., Ed., Lafon, Y., Ed., Nottingham, M., Ed., |  | [Part6] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, |
| and J. Reschke, Ed., "HTTP/1.1, part 6: Caching", |  | Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching", |
| draft-ietf-httpbis-p6-cache-20 (work in progress), |  | draft-ietf-httpbis-p6-cache-21 (work in progress), |
| July 2012. |  | October 2012. |
| [Part7] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed., |  | [Part7] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext |
| "HTTP/1.1, part 7: Authentication", |  | Transfer Protocol (HTTP/1.1): Authentication", |
| draft-ietf-httpbis-p7-auth-20 (work in progress), |  | draft-ietf-httpbis-p7-auth-21 (work in progress), |
| July 2012. |  | October 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 69, line 4 |  | skipping to change at page 65, line 29 |
| 10.2. Informative References |  | 10.2. Informative References |
| [ISO-8859-1] International Organization for Standardization, |  | [ISO-8859-1] International Organization for Standardization, |
| "Information technology -- 8-bit single-byte coded |  | "Information technology -- 8-bit single-byte coded |
| graphic character sets -- Part 1: Latin alphabet No. |  | graphic character sets -- Part 1: Latin alphabet No. |
| 1", ISO/IEC 8859-1:1998, 1998. |  | 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., |  |  |
| and C. Lilley, "Network Performance Effects of |  |  |
| HTTP/1.1, CSS1, and PNG", ACM Proceedings of the ACM |  |  |
| SIGCOMM '97 conference on Applications, technologies, |  |  |
| architectures, and protocols for computer communication |  |  |
| SIGCOMM '97, September 1997, |  |  |
| <http://doi.acm.org/10.1145/263105.263157>. |  |  |
| [Pad1995] Padmanabhan, V. and J. Mogul, "Improving HTTP Latency", |  |  |
| Computer Networks and ISDN Systems v. 28, pp. 25-35, |  |  |
| December 1995, |  |  |
| <http://portal.acm.org/citation.cfm?id=219094>. |  |  |
| [RFC1919] Chatel, M., "Classical versus Transparent IP Proxies", |  | [RFC1919] Chatel, M., "Classical versus Transparent IP Proxies", |
| RFC 1919, March 1996. |  | RFC 1919, March 1996. |
| [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, |  | [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, |
| "Hypertext Transfer Protocol -- HTTP/1.0", RFC 1945, |  | "Hypertext Transfer Protocol -- HTTP/1.0", RFC 1945, |
| May 1996. |  | May 1996. |
| [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet |  | [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet |
| Mail Extensions (MIME) Part One: Format of Internet |  | Mail Extensions (MIME) Part One: Format of Internet |
| Message Bodies", RFC 2045, November 1996. |  | Message Bodies", RFC 2045, November 1996. |
| skipping to change at page 70, line 36 |  | skipping to change at page 66, line 46 |
| BCP 115, RFC 4395, February 2006. |  | BCP 115, RFC 4395, February 2006. |
| [RFC4559] Jaganathan, K., Zhu, L., and J. Brezak, "SPNEGO-based |  | [RFC4559] Jaganathan, K., Zhu, L., and J. Brezak, "SPNEGO-based |
| Kerberos and NTLM HTTP Authentication in Microsoft |  | Kerberos and NTLM HTTP Authentication in Microsoft |
| Windows", RFC 4559, June 2006. |  | Windows", RFC 4559, June 2006. |
| [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing |  | [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing |
| an IANA Considerations Section in RFCs", BCP 26, |  | an IANA Considerations Section in RFCs", BCP 26, |
| RFC 5226, May 2008. |  | RFC 5226, May 2008. |
|  |  | [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer |
|  |  | Security (TLS) Protocol Version 1.2", RFC 5246, |
|  |  | August 2008. |
| [RFC5322] Resnick, P., "Internet Message Format", RFC 5322, |  | [RFC5322] Resnick, P., "Internet Message Format", RFC 5322, |
| October 2008. |  | October 2008. |
| [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, |  | [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, |
| April 2011. |  | April 2011. |
| [Spe] Spero, S., "Analysis of HTTP Performance Problems", |  |  |
| <http://sunsite.unc.edu/mdma-release/http-prob.html>. |  |  |
| [Tou1998] Touch, J., Heidemann, J., and K. Obraczka, "Analysis of |  |  |
| HTTP Performance", ISI Research Report ISI/RR-98-463, |  |  |
| Aug 1998, <http://www.isi.edu/touch/pubs/http-perf96/>. |  |  |
| (original report dated Aug. 1996) |  |  |
| Appendix A. HTTP Version History |  | Appendix A. HTTP Version History |
| HTTP has been in use by the World-Wide Web global information |  | HTTP has been in use by the World-Wide Web global information |
| initiative since 1990. The first version of HTTP, later referred to |  | initiative since 1990. The first version of HTTP, later referred to |
| as HTTP/0.9, was a simple protocol for hypertext data transfer across |  | as HTTP/0.9, was a simple protocol for hypertext data transfer across |
| the Internet with only a single request method (GET) and no metadata. |  | the Internet with only a single request method (GET) and no metadata. |
| HTTP/1.0, as defined by [RFC1945], added a range of request methods |  | HTTP/1.0, as defined by [RFC1945], added a range of request methods |
| and MIME-like messaging that could include metadata about the data |  | and MIME-like messaging that could include metadata about the data |
| transferred and modifiers on the request/response semantics. |  | transferred and modifiers on the request/response semantics. |
| However, HTTP/1.0 did not sufficiently take into consideration the |  | However, HTTP/1.0 did not sufficiently take into consideration the |
| skipping to change at page 73, line 17 |  | skipping to change at page 69, line 17 |
| HTTP/1.1 introduces the Transfer-Encoding header field |  | HTTP/1.1 introduces the Transfer-Encoding header field |
| (Section 3.3.1). Proxies/gateways MUST remove any transfer-coding |  | (Section 3.3.1). Proxies/gateways MUST remove any transfer-coding |
| prior to forwarding a message via a MIME-compliant protocol. |  | 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 ABNF 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 2.7) |  | version numbers incorrectly. (Section 2.6) |
| Update use of abs_path production from RFC 1808 to the path-absolute |  |  |
| + query components of RFC 3986. State that the asterisk form is |  |  |
| 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) |  | Change ABNF productions for header fields to only define the field |
|  |  | value. (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. |  | Require recipients to handle bogus "Content-Length" header fields as |
| (Appendix B) |  |  |
| 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 |  | Update use of abs_path production from RFC 1808 to the path-absolute |
| (Section 7.4) |  | + query components of RFC 3986. State that the asterisk form is |
|  |  | allowed for the OPTIONS request method only. (Section 5.3) |
|  |  | Clarify exactly when "close" connection options have to be sent; drop |
|  |  | notion of header fields being "hop-by-hop" without being listed in |
|  |  | the Connection header field. (Section 6.1) |
| 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 6.2) |
| Remove requirement to retry requests under certain circumstances 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 6.2.2) |
| Change ABNF productions for header fields to only define the field |  |  |
| value. |  |  |
| Clarify exactly when "close" connection options have to be sent. |  |  |
| (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 6.3) |
|  |  | Registration of Transfer Codings now requires IETF Review |
|  |  | (Section 7.4) |
| Take over the Upgrade Token Registry, previously defined in Section |  | Take over the Upgrade Token Registry, previously defined in Section |
| 7.2 of [RFC2817]. (Section 7.6) |  | 7.2 of [RFC2817]. (Section 7.6) |
|  |  | Empty list elements in list productions have been deprecated. |
|  |  | (Appendix B) |
| Appendix B. ABNF list extension: #rule |  | Appendix B. ABNF list extension: #rule |
| A #rule extension to the ABNF rules of [RFC5234] is used to improve |  | A #rule extension to the ABNF rules of [RFC5234] is used to improve |
| readability in the definitions of some header field values. |  | readability in the definitions of some header field values. |
| A construct "#" is defined, similar to "*", for defining comma- |  | A construct "#" is defined, similar to "*", for defining comma- |
| delimited lists of elements. The full form is "<n>#<m>element" |  | delimited lists of elements. The full form is "<n>#<m>element" |
| indicating at least <n> and at most <m> elements, each separated by a |  | indicating at least <n> and at most <m> elements, each separated by a |
| single comma (",") and optional whitespace (OWS). |  | single comma (",") and optional whitespace (OWS). |
| skipping to change at page 77, line 24 |  | skipping to change at page 73, line 21 |
| / %x5D-7E ; ']'-'~' |  | / %x5D-7E ; ']'-'~' |
| / obs-text |  | / obs-text |
| qdtext-nf = HTAB / SP / "!" / %x23-5B ; '#'-'[' |  | qdtext-nf = HTAB / SP / "!" / %x23-5B ; '#'-'[' |
| / %x5D-7E ; ']'-'~' |  | / %x5D-7E ; ']'-'~' |
| / obs-text |  | / obs-text |
| query = <query, defined in [RFC3986], Section 3.4> |  | query = <query, defined in [RFC3986], Section 3.4> |
| quoted-cpair = "\" ( HTAB / SP / VCHAR / obs-text ) |  | quoted-cpair = "\" ( HTAB / SP / VCHAR / obs-text ) |
| quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text ) |  | quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text ) |
| quoted-str-nf = DQUOTE *( qdtext-nf / quoted-pair ) DQUOTE |  | quoted-str-nf = DQUOTE *( qdtext-nf / quoted-pair ) DQUOTE |
| quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE |  | quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE |
| qvalue = ( "0" [ "." *3DIGIT ] ) / ( "1" [ "." *3"0" ] ) |  |  |
|  |  | rank = ( "0" [ "." *3DIGIT ] ) / ( "1" [ "." *3"0" ] ) |
| reason-phrase = *( HTAB / SP / VCHAR / obs-text ) |  | reason-phrase = *( HTAB / SP / VCHAR / obs-text ) |
| received-by = ( uri-host [ ":" port ] ) / pseudonym |  | received-by = ( uri-host [ ":" port ] ) / pseudonym |
| received-protocol = [ protocol-name "/" ] protocol-version |  | received-protocol = [ protocol-name "/" ] protocol-version |
| relative-part = <relative-part, defined in [RFC3986], Section 4.2> |  | relative-part = <relative-part, defined in [RFC3986], Section 4.2> |
| request-line = method SP request-target SP HTTP-version CRLF |  | request-line = method SP request-target SP HTTP-version CRLF |
| request-target = origin-form / absolute-form / authority-form / |  | request-target = origin-form / absolute-form / authority-form / |
| asterisk-form |  | asterisk-form |
| special = "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "\" / |  | special = "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "\" / |
| DQUOTE / "/" / "[" / "]" / "?" / "=" / "{" / "}" |  | DQUOTE / "/" / "[" / "]" / "?" / "=" / "{" / "}" |
| start-line = request-line / status-line |  | start-line = request-line / status-line |
| status-code = 3DIGIT |  | status-code = 3DIGIT |
| status-line = HTTP-version SP status-code SP reason-phrase CRLF |  | status-line = HTTP-version SP status-code SP reason-phrase CRLF |
| t-codings = "trailers" / ( transfer-extension [ te-params ] ) |  | t-codings = "trailers" / ( transfer-coding [ t-ranking ] ) |
|  |  | t-ranking = OWS ";" OWS "q=" rank |
| tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." / |  | tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." / |
| "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA |  | "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA |
| te-ext = OWS ";" OWS token [ "=" word ] |  |  |
| 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 |
| Appendix D. Change Log (to be removed by RFC Editor before publication) |  | Appendix D. Change Log (to be removed by RFC Editor before publication) |
| D.1. Since RFC 2616 |  | D.1. Since RFC 2616 |
| Extracted relevant partitions from [RFC2616]. |  | Extracted relevant partitions from [RFC2616]. |
| D.2. Since draft-ietf-httpbis-p1-messaging-00 |  | D.2. Since draft-ietf-httpbis-p1-messaging-00 |
| skipping to change at page 83, line 30 |  | skipping to change at page 79, line 24 |
| 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 payload 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" |
| D.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 header fields" |  | single-value header fields" |
| skipping to change at page 89, line 24 |  | skipping to change at page 85, line 17 |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/361>: "ABNF |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/361>: "ABNF |
| requirements for recipients" |  | requirements for recipients" |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/368>: "note |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/368>: "note |
| introduction of new IANA registries as normative changes" |  | introduction of new IANA registries as normative changes" |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/374>: "Reference to |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/374>: "Reference to |
| ISO-8859-1 is informative" |  | ISO-8859-1 is informative" |
|  |  | D.22. Since draft-ietf-httpbis-p1-messaging-20 |
|  |  | Closed issues: |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/378>: "is 'q=' case- |
|  |  | sensitive?" |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/383>: "Semantics of |
|  |  | HTTPS" |
|  |  | Other changes: |
|  |  | o Drop notion of header fields being "hop-by-hop" without being |
|  |  | listed in the Connection header field. |
|  |  | o Section about connection management rewritten; dropping some |
|  |  | historic information. |
|  |  | o Move description of "100-continue" into Part 2. |
|  |  | o Rewrite the persistent connection and Upgrade requirements to be |
|  |  | actionable by role and consistent with the rest of HTTP. |
| Index |  | Index |
| A |  | A |
| absolute-form (of request-target) 41 |  | absolute-form (of request-target) 39 |
| accelerator 11 |  | accelerator 10 |
| application/http Media Type 60 |  | application/http Media Type 57 |
| asterisk-form (of request-target) 41 |  | asterisk-form (of request-target) 39 |
| authority-form (of request-target) 41 |  | authority-form (of request-target) 39 |
| B |  | B |
| browser 8 |  | browser 7 |
| C |  | C |
| cache 13 |  | cache 11 |
| cacheable 13 |  | cacheable 12 |
| captive portal 12 |  | captive portal 11 |
| chunked (Coding Format) 34 |  | chunked (Coding Format) 33 |
| client 7 |  | client 7 |
| Coding Format |  | close 46, 52 |
| chunked 34 |  | compress (Coding Format) 35 |
| compress 36 |  |  |
| deflate 36 |  |  |
| gzip 36 |  |  |
| compress (Coding Format) 36 |  |  |
| connection 7 |  | connection 7 |
| Connection header field 47 |  | Connection header field 46, 52 |
| Content-Length header field 29 |  | Content-Length header field 28 |
| D |  | D |
| deflate (Coding Format) 36 |  | deflate (Coding Format) 35 |
| downstream 11 |  | downstream 9 |
| E |  | E |
| effective request URI 43 |  | effective request URI 41 |
| G |  | G |
| gateway 11 |  | gateway 10 |
| Grammar |  | Grammar |
| absolute-form 40 |  | absolute-form 38 |
| absolute-URI 17 |  | absolute-URI 15 |
| ALPHA 7 |  | ALPHA 6 |
| asterisk-form 40 |  | asterisk-form 38 |
| attribute 34 |  | attribute 33 |
| authority 17 |  | authority 15 |
| authority-form 40 |  | authority-form 38 |
| BWS 24 |  | BWS 23 |
| chunk 34 |  | chunk 33 |
| chunk-data 34 |  | chunk-data 33 |
| chunk-ext 34 |  | chunk-ext 33 |
| chunk-ext-name 34 |  | chunk-ext-name 33 |
| chunk-ext-val 34 |  | chunk-ext-val 33 |
| chunk-size 34 |  | chunk-size 33 |
| chunked-body 34 |  | chunked-body 33 |
| comment 27 |  | comment 25 |
| Connection 47 |  | Connection 47 |
| connection-option 47 |  | connection-option 47 |
| Content-Length 29 |  | Content-Length 28 |
| CR 7 |  | CR 6 |
| CRLF 7 |  | CRLF 6 |
| ctext 27 |  | ctext 25 |
| CTL 7 |  | CTL 6 |
| date2 34 |  | date2 33 |
| date3 34 |  | date3 33 |
| DIGIT 7 |  | DIGIT 6 |
| DQUOTE 7 |  | DQUOTE 6 |
| field-content 23 |  | field-content 21 |
| field-name 23 |  | field-name 21 |
| field-value 23 |  | field-value 21 |
| header-field 23 |  | header-field 21 |
| HEXDIG 7 |  | HEXDIG 6 |
| Host 42 |  | Host 40 |
| HTAB 7 |  | HTAB 6 |
| HTTP-message 20 |  | HTTP-message 18 |
| HTTP-name 14 |  | HTTP-name 13 |
| http-URI 17 |  | http-URI 16 |
| HTTP-version 14 |  | HTTP-version 13 |
| https-URI 19 |  | https-URI 17 |
| last-chunk 34 |  | last-chunk 33 |
| LF 7 |  | LF 6 |
| message-body 27 |  | message-body 26 |
| method 21 |  | method 20 |
| obs-fold 23 |  | obs-fold 21 |
| obs-text 26 |  | obs-text 25 |
| OCTET 7 |  | OCTET 6 |
| origin-form 40 |  | origin-form 38 |
| OWS 24 |  | OWS 23 |
| partial-URI 17 |  | partial-URI 15 |
| path-absolute 17 |  | path-absolute 15 |
| port 17 |  | port 15 |
| protocol-name 49 |  | protocol-name 43 |
| protocol-version 49 |  | protocol-version 43 |
| pseudonym 49 |  | pseudonym 43 |
| qdtext 26 |  | qdtext 25 |
| qdtext-nf 34 |  | qdtext-nf 33 |
| query 17 |  | query 15 |
| quoted-cpair 27 |  | quoted-cpair 25 |
| quoted-pair 26 |  | quoted-pair 25 |
| quoted-str-nf 34 |  | quoted-str-nf 33 |
| quoted-string 26 |  | quoted-string 25 |
| qvalue 38 |  | rank 36 |
| reason-phrase 22 |  | reason-phrase 21 |
| received-by 49 |  | received-by 43 |
| received-protocol 49 |  | received-protocol 43 |
| request-line 21 |  | request-line 20 |
| request-target 40 |  | request-target 38 |
| RWS 24 |  | RWS 23 |
| SP 7 |  | SP 6 |
| special 26 |  | special 25 |
| start-line 21 |  | start-line 19 |
| status-code 22 |  | status-code 21 |
| status-line 22 |  | status-line 21 |
| t-codings 37 |  | t-codings 36 |
| tchar 26 |  | t-ranking 36 |
| TE 37 |  | tchar 25 |
| te-ext 37 |  | TE 36 |
| te-params 37 |  | token 25 |
| token 26 |  | Trailer 34 |
| Trailer 38 |  | trailer-part 33 |
| trailer-part 34 |  | transfer-coding 33 |
| transfer-coding 34 |  | Transfer-Encoding 26 |
| Transfer-Encoding 28 |  | transfer-extension 33 |
| transfer-extension 34 |  | transfer-parameter 33 |
| transfer-parameter 34 |  | Upgrade 53 |
| Upgrade 57 |  | uri-host 15 |
| uri-host 17 |  | URI-reference 15 |
| URI-reference 17 |  | value 33 |
| value 34 |  | VCHAR 6 |
| VCHAR 7 |  | Via 43 |
| Via 49 |  | word 25 |
| word 26 |  |  |
| gzip (Coding Format) 36 |  | gzip (Coding Format) 36 |
| H |  | H |
| header field 20 |  | header field 18 |
| Header Fields |  | header section 18 |
| Connection 47 |  | headers 18 |
| Content-Length 29 |  | Host header field 40 |
| Host 42 |  | http URI scheme 16 |
| TE 36 |  | https URI scheme 17 |
| Trailer 38 |  |  |
| Transfer-Encoding 27 |  |  |
| Upgrade 56 |  |  |
| Via 49 |  |  |
| header section 20 |  |  |
| headers 20 |  |  |
| Host header field 42 |  |  |
| http URI scheme 17 |  |  |
| https URI scheme 18 |  |  |
| I |  | I |
| inbound 11 |  | inbound 9 |
| interception proxy 12 |  | interception proxy 11 |
| intermediary 10 |  | intermediary 9 |
| M |  | M |
| Media Type |  | Media Type |
| application/http 60 |  | application/http 57 |
| message/http 59 |  | message/http 56 |
| message 8 |  | message 7 |
| message/http Media Type 59 |  | message/http Media Type 56 |
| method 21 |  | method 20 |
| N |  | N |
| non-transforming proxy 11 |  | non-transforming proxy 10 |
| O |  | O |
| origin server 8 |  | origin server 7 |
| origin-form (of request-target) 40 |  | origin-form (of request-target) 38 |
| outbound 11 |  | outbound 9 |
| P |  | P |
| proxy 11 |  | proxy 10 |
| R |  | R |
| recipient 8 |  | recipient 7 |
| request 8 |  | request 7 |
| request-target 21 |  | request-target 20 |
| resource 16 |  | resource 15 |
| response 8 |  | response 7 |
| reverse proxy 11 |  | reverse proxy 10 |
| S |  | S |
| sender 8 |  | sender 7 |
| server 7 |  | server 7 |
| spider 8 |  | spider 7 |
| T |  | T |
| target resource 39 |  | target resource 37 |
| target URI 39 |  | target URI 37 |
| TE header field 36 |  | TE header field 36 |
| Trailer header field 38 |  | Trailer header field 34 |
| Transfer-Encoding header field 27 |  | Transfer-Encoding header field 26 |
| transforming proxy 11 |  | transforming proxy 10 |
| transparent proxy 12 |  | transparent proxy 11 |
| tunnel 12 |  | tunnel 11 |
| U |  | U |
| Upgrade header field 56 |  | Upgrade header field 53 |
| upstream 11 |  | upstream 9 |
| URI scheme |  | URI scheme |
| http 17 |  | http 16 |
| https 18 |  | https 17 |
| user agent 8 |  | user agent 7 |
| V |  | V |
| Via header field 49 |  | Via header field 43 |
| Authors' Addresses |  | Authors' Addresses |
| Roy T. Fielding (editor) |  | Roy T. Fielding (editor) |
| Adobe Systems Incorporated |  | Adobe Systems Incorporated |
| 345 Park Ave |  | 345 Park Ave |
| San Jose, CA 95110 |  | San Jose, CA 95110 |
| USA |  | USA |
| EMail: fielding@gbiv.com |  | EMail: fielding@gbiv.com |
| URI: http://roy.gbiv.com/ |  | URI: http://roy.gbiv.com/ |
| Yves Lafon (editor) |  |  |
| World Wide Web Consortium |  |  |
| W3C / ERCIM |  |  |
| 2004, rte des Lucioles |  |  |
| Sophia-Antipolis, AM 06902 |  |  |
| France |  |  |
| EMail: ylafon@w3.org |  |  |
| 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 |
| EMail: julian.reschke@greenbytes.de |  | EMail: julian.reschke@greenbytes.de |
| URI: http://greenbytes.de/tech/webdav/ |  | URI: http://greenbytes.de/tech/webdav/ |
End of changes. 236 change blocks.
| 1126 lines changed or deleted |  | 986 lines changed or added |
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