| draft-ietf-httpbis-p1-messaging-16.txt |  | draft-ietf-httpbis-p1-messaging-17.txt |
--- | --- | --- | --- | ---
| HTTPbis Working Group R. Fielding, Ed. |  | HTTPbis Working Group R. Fielding, Ed. |
| Internet-Draft Adobe |  | Internet-Draft Adobe |
| Obsoletes: 2145,2616 (if approved) J. Gettys |  | Obsoletes: 2145,2616 (if approved) J. Gettys |
| Updates: 2817 (if approved) Alcatel-Lucent |  | Updates: 2817 (if approved) Alcatel-Lucent |
| Intended status: Standards Track J. Mogul |  | Intended status: Standards Track J. Mogul |
| Expires: February 25, 2012 HP |  | Expires: May 3, 2012 HP |
| H. Frystyk |  | H. Frystyk |
| Microsoft |  | Microsoft |
| L. Masinter |  | L. Masinter |
| Adobe |  | Adobe |
| P. Leach |  | P. Leach |
| Microsoft |  | Microsoft |
| T. Berners-Lee |  | T. Berners-Lee |
| W3C/MIT |  | W3C/MIT |
| Y. Lafon, Ed. |  | Y. Lafon, Ed. |
| W3C |  | W3C |
| J. Reschke, Ed. |  | J. Reschke, Ed. |
| greenbytes |  | greenbytes |
| August 24, 2011 |  | October 31, 2011 |
| HTTP/1.1, part 1: URIs, Connections, and Message Parsing |  | HTTP/1.1, part 1: URIs, Connections, and Message Parsing |
| draft-ietf-httpbis-p1-messaging-16 |  | draft-ietf-httpbis-p1-messaging-17 |
| Abstract |  | Abstract |
| The Hypertext Transfer Protocol (HTTP) is an application-level |  | The Hypertext Transfer Protocol (HTTP) is an application-level |
| protocol for distributed, collaborative, hypertext information |  | protocol for distributed, collaborative, hypertext information |
| systems. HTTP has been in use by the World Wide Web global |  | systems. HTTP has been in use by the World Wide Web global |
| information initiative since 1990. This document is Part 1 of the |  | information initiative since 1990. This document is Part 1 of the |
| seven-part specification that defines the protocol referred to as |  | seven-part specification that defines the protocol referred to as |
| "HTTP/1.1" and, taken together, obsoletes RFC 2616 and moves it to |  | "HTTP/1.1" and, taken together, obsoletes RFC 2616 and moves it to |
| historic status, along with its predecessor RFC 2068. |  | historic status, along with its predecessor RFC 2068. |
| skipping to change at page 2, line 11 |  | skipping to change at page 2, line 11 |
| Discussion of this draft should take place on the HTTPBIS working |  | Discussion of this draft should take place on the HTTPBIS working |
| group mailing list (ietf-http-wg@w3.org), which is archived at |  | group mailing list (ietf-http-wg@w3.org), which is archived at |
| <http://lists.w3.org/Archives/Public/ietf-http-wg/>. |  | <http://lists.w3.org/Archives/Public/ietf-http-wg/>. |
| The current issues list is at |  | The current issues list is at |
| <http://tools.ietf.org/wg/httpbis/trac/report/3> and related |  | <http://tools.ietf.org/wg/httpbis/trac/report/3> and related |
| documents (including fancy diffs) can be found at |  | documents (including fancy diffs) can be found at |
| <http://tools.ietf.org/wg/httpbis/>. |  | <http://tools.ietf.org/wg/httpbis/>. |
| The changes in this draft are summarized in Appendix C.17. |  | The changes in this draft are summarized in Appendix C.18. |
| 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 February 25, 2012. |  | This Internet-Draft will expire on May 3, 2012. |
| Copyright Notice |  | Copyright Notice |
| Copyright (c) 2011 IETF Trust and the persons identified as the |  | Copyright (c) 2011 IETF Trust and the persons identified as the |
| document authors. All rights reserved. |  | document authors. All rights reserved. |
| This document is subject to BCP 78 and the IETF Trust's Legal |  | This document is subject to BCP 78 and the IETF Trust's Legal |
| Provisions Relating to IETF Documents |  | Provisions Relating to IETF Documents |
| (http://trustee.ietf.org/license-info) in effect on the date of |  | (http://trustee.ietf.org/license-info) in effect on the date of |
| publication of this document. Please review these documents |  | publication of this document. Please review these documents |
| skipping to change at page 3, line 12 |  | skipping to change at page 3, line 12 |
| 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 . . . . . . . . . . . . . . . . . . . . . . . . . 6 |
| 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 7 |  | 1.1. Conformance and Error Handling . . . . . . . . . . . . . . 7 |
| 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 7 |  | 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 7 |
| 1.2.1. ABNF Extension: #rule . . . . . . . . . . . . . . . . 7 |  | 1.2.1. ABNF Extension: #rule . . . . . . . . . . . . . . . . 8 |
| 1.2.2. Basic Rules . . . . . . . . . . . . . . . . . . . . . 8 |  | 1.2.2. Basic Rules . . . . . . . . . . . . . . . . . . . . . 9 |
| 2. HTTP-related architecture . . . . . . . . . . . . . . . . . . 9 |  | 2. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 9 |
| 2.1. Client/Server Messaging . . . . . . . . . . . . . . . . . 9 |  | 2.1. Client/Server Messaging . . . . . . . . . . . . . . . . . 10 |
| 2.2. Message Orientation and Buffering . . . . . . . . . . . . 11 |  | 2.2. Message Orientation and Buffering . . . . . . . . . . . . 11 |
| 2.3. Connections and Transport Independence . . . . . . . . . . 11 |  | 2.3. Connections and Transport Independence . . . . . . . . . . 12 |
| 2.4. Intermediaries . . . . . . . . . . . . . . . . . . . . . . 12 |  | 2.4. Intermediaries . . . . . . . . . . . . . . . . . . . . . . 12 |
| 2.5. Caches . . . . . . . . . . . . . . . . . . . . . . . . . . 14 |  | 2.5. Caches . . . . . . . . . . . . . . . . . . . . . . . . . . 14 |
| 2.6. Protocol Versioning . . . . . . . . . . . . . . . . . . . 15 |  | 2.6. Protocol Versioning . . . . . . . . . . . . . . . . . . . 15 |
| 2.7. Uniform Resource Identifiers . . . . . . . . . . . . . . . 17 |  | 2.7. Uniform Resource Identifiers . . . . . . . . . . . . . . . 17 |
| 2.7.1. http URI scheme . . . . . . . . . . . . . . . . . . . 18 |  | 2.7.1. http URI scheme . . . . . . . . . . . . . . . . . . . 18 |
| 2.7.2. https URI scheme . . . . . . . . . . . . . . . . . . . 19 |  | 2.7.2. https URI scheme . . . . . . . . . . . . . . . . . . . 19 |
| 2.7.3. http and https URI Normalization and Comparison . . . 20 |  | 2.7.3. http and https URI Normalization and Comparison . . . 20 |
| 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 20 |  | 3. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 20 |
| 3.1. Message Parsing and Robustness . . . . . . . . . . . . . . 21 |  | 3.1. Start Line . . . . . . . . . . . . . . . . . . . . . . . . 21 |
| 3.2. Header Fields . . . . . . . . . . . . . . . . . . . . . . 22 |  | 3.1.1. Request-Line . . . . . . . . . . . . . . . . . . . . . 22 |
| 3.2.1. Field Parsing . . . . . . . . . . . . . . . . . . . . 23 |  | 3.1.2. Response Status-Line . . . . . . . . . . . . . . . . . 23 |
| 3.2.2. Field Length . . . . . . . . . . . . . . . . . . . . . 24 |  | 3.2. Header Fields . . . . . . . . . . . . . . . . . . . . . . 23 |
| 3.2.3. Common Field ABNF Rules . . . . . . . . . . . . . . . 24 |  | 3.2.1. Field Parsing . . . . . . . . . . . . . . . . . . . . 24 |
| 3.3. Message Body . . . . . . . . . . . . . . . . . . . . . . . 25 |  | 3.2.2. Field Length . . . . . . . . . . . . . . . . . . . . . 25 |
| 3.4. Incomplete Messages . . . . . . . . . . . . . . . . . . . 28 |  | 3.2.3. Common Field ABNF Rules . . . . . . . . . . . . . . . 25 |
| 3.5. General Header Fields . . . . . . . . . . . . . . . . . . 29 |  | 3.3. Message Body . . . . . . . . . . . . . . . . . . . . . . . 27 |
| 4. Request . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 |  | 3.4. Handling Incomplete Messages . . . . . . . . . . . . . . . 30 |
| 4.1. Request-Line . . . . . . . . . . . . . . . . . . . . . . . 30 |  | 3.5. Message Parsing Robustness . . . . . . . . . . . . . . . . 30 |
| 4.1.1. Method . . . . . . . . . . . . . . . . . . . . . . . . 30 |  | 4. Message Routing . . . . . . . . . . . . . . . . . . . . . . . 31 |
| 4.1.2. request-target . . . . . . . . . . . . . . . . . . . . 30 |  | 4.1. Types of Request Target . . . . . . . . . . . . . . . . . 31 |
| 4.2. The Resource Identified by a Request . . . . . . . . . . . 32 |  | 4.2. The Resource Identified by a Request . . . . . . . . . . . 33 |
| 4.3. Effective Request URI . . . . . . . . . . . . . . . . . . 33 |  | 4.3. Effective Request URI . . . . . . . . . . . . . . . . . . 34 |
| 5. Response . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 |  | 5. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 35 |
| 5.1. Status-Line . . . . . . . . . . . . . . . . . . . . . . . 34 |  | 5.1. Transfer Codings . . . . . . . . . . . . . . . . . . . . . 35 |
| 5.1.1. Status Code and Reason Phrase . . . . . . . . . . . . 35 |  | 5.1.1. Chunked Transfer Coding . . . . . . . . . . . . . . . 36 |
| 6. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 35 |  | 5.1.2. Compression Codings . . . . . . . . . . . . . . . . . 38 |
| 6.1. Date/Time Formats: Full Date . . . . . . . . . . . . . . . 35 |  | 5.1.3. Transfer Coding Registry . . . . . . . . . . . . . . . 39 |
| 6.2. Transfer Codings . . . . . . . . . . . . . . . . . . . . . 38 |  | 5.2. Product Tokens . . . . . . . . . . . . . . . . . . . . . . 39 |
| 6.2.1. Chunked Transfer Coding . . . . . . . . . . . . . . . 39 |  | 5.3. Quality Values . . . . . . . . . . . . . . . . . . . . . . 40 |
| 6.2.2. Compression Codings . . . . . . . . . . . . . . . . . 41 |  | 6. Connections . . . . . . . . . . . . . . . . . . . . . . . . . 40 |
| 6.2.3. Transfer Coding Registry . . . . . . . . . . . . . . . 42 |  | 6.1. Persistent Connections . . . . . . . . . . . . . . . . . . 40 |
| 6.3. Product Tokens . . . . . . . . . . . . . . . . . . . . . . 43 |  | 6.1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . 40 |
| 6.4. Quality Values . . . . . . . . . . . . . . . . . . . . . . 43 |  | 6.1.2. Overall Operation . . . . . . . . . . . . . . . . . . 41 |
| 7. Connections . . . . . . . . . . . . . . . . . . . . . . . . . 43 |  | 6.1.3. Proxy Servers . . . . . . . . . . . . . . . . . . . . 42 |
| 7.1. Persistent Connections . . . . . . . . . . . . . . . . . . 44 |  | 6.1.4. Practical Considerations . . . . . . . . . . . . . . . 45 |
| 7.1.1. Purpose . . . . . . . . . . . . . . . . . . . . . . . 44 |  | 6.1.5. Retrying Requests . . . . . . . . . . . . . . . . . . 46 |
| 7.1.2. Overall Operation . . . . . . . . . . . . . . . . . . 44 |  | 6.2. Message Transmission Requirements . . . . . . . . . . . . 46 |
| 7.1.3. Proxy Servers . . . . . . . . . . . . . . . . . . . . 46 |  | 6.2.1. Persistent Connections and Flow Control . . . . . . . 46 |
| 7.1.4. Practical Considerations . . . . . . . . . . . . . . . 48 |  | 6.2.2. Monitoring Connections for Error Status Messages . . . 46 |
| 7.2. Message Transmission Requirements . . . . . . . . . . . . 49 |  | 6.2.3. Use of the 100 (Continue) Status . . . . . . . . . . . 46 |
| 7.2.1. Persistent Connections and Flow Control . . . . . . . 49 |  | 7. Miscellaneous notes that might disappear . . . . . . . . . . . 48 |
| 7.2.2. Monitoring Connections for Error Status Messages . . . 50 |  | 7.1. Scheme aliases considered harmful . . . . . . . . . . . . 48 |
| 7.2.3. Use of the 100 (Continue) Status . . . . . . . . . . . 50 |  | 7.2. Use of HTTP for proxy communication . . . . . . . . . . . 49 |
| 7.2.4. Client Behavior if Server Prematurely Closes |  | 7.3. Interception of HTTP for access control . . . . . . . . . 49 |
| Connection . . . . . . . . . . . . . . . . . . . . . . 52 |  | 7.4. Use of HTTP by other protocols . . . . . . . . . . . . . . 49 |
| 8. Miscellaneous notes that might disappear . . . . . . . . . . . 53 |  | 7.5. Use of HTTP by media type specification . . . . . . . . . 49 |
| 8.1. Scheme aliases considered harmful . . . . . . . . . . . . 53 |  | 8. Header Field Definitions . . . . . . . . . . . . . . . . . . . 49 |
| 8.2. Use of HTTP for proxy communication . . . . . . . . . . . 53 |  | 8.1. Connection . . . . . . . . . . . . . . . . . . . . . . . . 49 |
| 8.3. Interception of HTTP for access control . . . . . . . . . 53 |  | 8.2. Content-Length . . . . . . . . . . . . . . . . . . . . . . 51 |
| 8.4. Use of HTTP by other protocols . . . . . . . . . . . . . . 53 |  | 8.3. Host . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 |
| 8.5. Use of HTTP by media type specification . . . . . . . . . 53 |  | 8.4. TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 |
| 9. Header Field Definitions . . . . . . . . . . . . . . . . . . . 53 |  | 8.5. Trailer . . . . . . . . . . . . . . . . . . . . . . . . . 54 |
| 9.1. Connection . . . . . . . . . . . . . . . . . . . . . . . . 53 |  | 8.6. Transfer-Encoding . . . . . . . . . . . . . . . . . . . . 54 |
| 9.2. Content-Length . . . . . . . . . . . . . . . . . . . . . . 55 |  | 8.7. Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 55 |
| 9.3. Date . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 |  | 8.7.1. Upgrade Token Registry . . . . . . . . . . . . . . . . 56 |
| 9.3.1. Clockless Origin Server Operation . . . . . . . . . . 56 |  | 8.8. Via . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 |
| 9.4. Host . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 |  | 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58 |
| 9.5. TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 |  | 9.1. Header Field Registration . . . . . . . . . . . . . . . . 58 |
| 9.6. Trailer . . . . . . . . . . . . . . . . . . . . . . . . . 59 |  | 9.2. URI Scheme Registration . . . . . . . . . . . . . . . . . 59 |
| 9.7. Transfer-Encoding . . . . . . . . . . . . . . . . . . . . 59 |  | 9.3. Internet Media Type Registrations . . . . . . . . . . . . 59 |
| 9.8. Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . 60 |  | 9.3.1. Internet Media Type message/http . . . . . . . . . . . 59 |
| 9.8.1. Upgrade Token Registry . . . . . . . . . . . . . . . . 61 |  | 9.3.2. Internet Media Type application/http . . . . . . . . . 61 |
| 9.9. Via . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 |  | 9.4. Transfer Coding Registry . . . . . . . . . . . . . . . . . 62 |
| 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 63 |  | 9.5. Upgrade Token Registration . . . . . . . . . . . . . . . . 62 |
| 10.1. Header Field Registration . . . . . . . . . . . . . . . . 63 |  | 10. Security Considerations . . . . . . . . . . . . . . . . . . . 62 |
| 10.2. URI Scheme Registration . . . . . . . . . . . . . . . . . 64 |  | 10.1. Personal Information . . . . . . . . . . . . . . . . . . . 63 |
| 10.3. Internet Media Type Registrations . . . . . . . . . . . . 64 |  | 10.2. Abuse of Server Log Information . . . . . . . . . . . . . 63 |
| 10.3.1. Internet Media Type message/http . . . . . . . . . . . 64 |  | 10.3. Attacks Based On File and Path Names . . . . . . . . . . . 63 |
| 10.3.2. Internet Media Type application/http . . . . . . . . . 66 |  | 10.4. DNS-related Attacks . . . . . . . . . . . . . . . . . . . 63 |
| 10.4. Transfer Coding Registry . . . . . . . . . . . . . . . . . 67 |  | 10.5. Proxies and Caching . . . . . . . . . . . . . . . . . . . 64 |
| 10.5. Upgrade Token Registration . . . . . . . . . . . . . . . . 67 |  | 10.6. Protocol Element Size Overflows . . . . . . . . . . . . . 64 |
| 11. Security Considerations . . . . . . . . . . . . . . . . . . . 67 |  | 10.7. Denial of Service Attacks on Proxies . . . . . . . . . . . 65 |
| 11.1. Personal Information . . . . . . . . . . . . . . . . . . . 68 |  | 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 65 |
| 11.2. Abuse of Server Log Information . . . . . . . . . . . . . 68 |  | 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 66 |
| 11.3. Attacks Based On File and Path Names . . . . . . . . . . . 68 |  | 12.1. Normative References . . . . . . . . . . . . . . . . . . . 66 |
| 11.4. DNS-related Attacks . . . . . . . . . . . . . . . . . . . 68 |  | 12.2. Informative References . . . . . . . . . . . . . . . . . . 68 |
| 11.5. Proxies and Caching . . . . . . . . . . . . . . . . . . . 69 |  | Appendix A. HTTP Version History . . . . . . . . . . . . . . . . 70 |
| 11.6. Protocol Element Size Overflows . . . . . . . . . . . . . 69 |  | A.1. Changes from HTTP/1.0 . . . . . . . . . . . . . . . . . . 71 |
| 11.7. Denial of Service Attacks on Proxies . . . . . . . . . . . 70 |  | A.1.1. Multi-homed Web Servers . . . . . . . . . . . . . . . 71 |
| 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 70 |  | A.1.2. Keep-Alive Connections . . . . . . . . . . . . . . . . 71 |
| 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 70 |  |  |
| 13.1. Normative References . . . . . . . . . . . . . . . . . . . 70 |  | A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 72 |
| 13.2. Informative References . . . . . . . . . . . . . . . . . . 72 |  | Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 73 |
| Appendix A. HTTP Version History . . . . . . . . . . . . . . . . 74 |  |  |
| A.1. Changes from HTTP/1.0 . . . . . . . . . . . . . . . . . . 75 |  |  |
| A.1.1. Multi-homed Web Servers . . . . . . . . . . . . . . . 75 |  |  |
| A.1.2. Keep-Alive Connections . . . . . . . . . . . . . . . . 75 |  |  |
| A.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 76 |  |  |
| Appendix B. Collected ABNF . . . . . . . . . . . . . . . . . . . 77 |  |  |
| Appendix C. Change Log (to be removed by RFC Editor before |  | Appendix C. Change Log (to be removed by RFC Editor before |
| publication) . . . . . . . . . . . . . . . . . . . . 81 |  | publication) . . . . . . . . . . . . . . . . . . . . 76 |
| C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 81 |  | C.1. Since RFC 2616 . . . . . . . . . . . . . . . . . . . . . . 76 |
| C.2. Since draft-ietf-httpbis-p1-messaging-00 . . . . . . . . . 81 |  | C.2. Since draft-ietf-httpbis-p1-messaging-00 . . . . . . . . . 76 |
| C.3. Since draft-ietf-httpbis-p1-messaging-01 . . . . . . . . . 83 |  | C.3. Since draft-ietf-httpbis-p1-messaging-01 . . . . . . . . . 78 |
| C.4. Since draft-ietf-httpbis-p1-messaging-02 . . . . . . . . . 84 |  | C.4. Since draft-ietf-httpbis-p1-messaging-02 . . . . . . . . . 79 |
| C.5. Since draft-ietf-httpbis-p1-messaging-03 . . . . . . . . . 84 |  | C.5. Since draft-ietf-httpbis-p1-messaging-03 . . . . . . . . . 79 |
| C.6. Since draft-ietf-httpbis-p1-messaging-04 . . . . . . . . . 85 |  | C.6. Since draft-ietf-httpbis-p1-messaging-04 . . . . . . . . . 80 |
| C.7. Since draft-ietf-httpbis-p1-messaging-05 . . . . . . . . . 85 |  | C.7. Since draft-ietf-httpbis-p1-messaging-05 . . . . . . . . . 80 |
| C.8. Since draft-ietf-httpbis-p1-messaging-06 . . . . . . . . . 86 |  | C.8. Since draft-ietf-httpbis-p1-messaging-06 . . . . . . . . . 81 |
| C.9. Since draft-ietf-httpbis-p1-messaging-07 . . . . . . . . . 87 |  | C.9. Since draft-ietf-httpbis-p1-messaging-07 . . . . . . . . . 82 |
| C.10. Since draft-ietf-httpbis-p1-messaging-08 . . . . . . . . . 87 |  | C.10. Since draft-ietf-httpbis-p1-messaging-08 . . . . . . . . . 82 |
| C.11. Since draft-ietf-httpbis-p1-messaging-09 . . . . . . . . . 88 |  | C.11. Since draft-ietf-httpbis-p1-messaging-09 . . . . . . . . . 83 |
| C.12. Since draft-ietf-httpbis-p1-messaging-10 . . . . . . . . . 88 |  | C.12. Since draft-ietf-httpbis-p1-messaging-10 . . . . . . . . . 83 |
| C.13. Since draft-ietf-httpbis-p1-messaging-11 . . . . . . . . . 89 |  | C.13. Since draft-ietf-httpbis-p1-messaging-11 . . . . . . . . . 84 |
| C.14. Since draft-ietf-httpbis-p1-messaging-12 . . . . . . . . . 89 |  | C.14. Since draft-ietf-httpbis-p1-messaging-12 . . . . . . . . . 84 |
| C.15. Since draft-ietf-httpbis-p1-messaging-13 . . . . . . . . . 90 |  | C.15. Since draft-ietf-httpbis-p1-messaging-13 . . . . . . . . . 85 |
| C.16. Since draft-ietf-httpbis-p1-messaging-14 . . . . . . . . . 90 |  | C.16. Since draft-ietf-httpbis-p1-messaging-14 . . . . . . . . . 85 |
| C.17. Since draft-ietf-httpbis-p1-messaging-15 . . . . . . . . . 90 |  | C.17. Since draft-ietf-httpbis-p1-messaging-15 . . . . . . . . . 85 |
| Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 |  | C.18. Since draft-ietf-httpbis-p1-messaging-16 . . . . . . . . . 86 |
|  |  | Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 |
| 1. Introduction |  | 1. Introduction |
| The Hypertext Transfer Protocol (HTTP) is an application-level |  | The Hypertext Transfer Protocol (HTTP) is an application-level |
| request/response protocol that uses extensible semantics and MIME- |  | request/response protocol that uses extensible semantics and MIME- |
| like message payloads for flexible interaction with network-based |  | like message payloads for flexible interaction with network-based |
| hypertext information systems. HTTP relies upon the Uniform Resource |  | hypertext information systems. HTTP relies upon the Uniform Resource |
| Identifier (URI) standard [RFC3986] to indicate the target resource |  | Identifier (URI) standard [RFC3986] to indicate the target resource |
| and relationships between resources. Messages are passed in a format |  | and relationships between resources. Messages are passed in a format |
| similar to that used by Internet mail [RFC5322] and the Multipurpose |  | similar to that used by Internet mail [RFC5322] and the Multipurpose |
| skipping to change at page 7, line 6 |  | skipping to change at page 7, line 6 |
| defining the protocol referred to as "HTTP/1.1", obsoleting [RFC2616] |  | defining the protocol referred to as "HTTP/1.1", obsoleting [RFC2616] |
| and [RFC2145]. Part 1 describes the architectural elements that are |  | and [RFC2145]. Part 1 describes the architectural elements that are |
| used or referred to in HTTP, defines the "http" and "https" URI |  | used or referred to in HTTP, defines the "http" and "https" URI |
| schemes, describes overall network operation and connection |  | schemes, describes overall network operation and connection |
| management, and defines HTTP message framing and forwarding |  | management, and defines HTTP message framing and forwarding |
| requirements. Our goal is to define all of the mechanisms necessary |  | requirements. Our goal is to define all of the mechanisms necessary |
| for HTTP message handling that are independent of message semantics, |  | for HTTP message handling that are independent of message semantics, |
| thereby defining the complete set of requirements for message parsers |  | thereby defining the complete set of requirements for message parsers |
| and message-forwarding intermediaries. |  | and message-forwarding intermediaries. |
| 1.1. Requirements |  | 1.1. Conformance and Error Handling |
| The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", |  | The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", |
| "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this |  | "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this |
| document are to be interpreted as described in [RFC2119]. |  | document are to be interpreted as described in [RFC2119]. |
| An implementation is not compliant if it fails to satisfy one or more |  | This document defines conformance criteria for several roles in HTTP |
| of the "MUST" or "REQUIRED" level requirements for the protocols it |  | communication, including Senders, Recipients, Clients, Servers, User- |
| implements. An implementation that satisfies all the "MUST" or |  | Agents, Origin Servers, Intermediaries, Proxies and Gateways. See |
| "REQUIRED" level and all the "SHOULD" level requirements for its |  | Section 2 for definitions of these terms. |
| protocols is said to be "unconditionally compliant"; one that |  |  |
| satisfies all the "MUST" level requirements but not all the "SHOULD" |  | An implementation is considered conformant if it complies with all of |
| level requirements for its protocols is said to be "conditionally |  | the requirements associated with its role(s). Note that SHOULD-level |
| compliant". |  | requirements are relevant here, unless one of the documented |
|  |  | exceptions is applicable. |
|  |  | This document also uses ABNF to define valid protocol elements |
|  |  | (Section 1.2). In addition to the prose requirements placed upon |
|  |  | them, Senders MUST NOT generate protocol elements that are invalid. |
|  |  | Unless noted otherwise, Recipients MAY take steps to recover a usable |
|  |  | protocol element from an invalid construct. However, HTTP does not |
|  |  | define specific error handling mechanisms, except in cases where it |
|  |  | has direct impact on security. This is because different uses of the |
|  |  | protocol require different error handling strategies; for example, a |
|  |  | Web browser may wish to transparently recover from a response where |
|  |  | the Location header field doesn't parse according to the ABNF, |
|  |  | whereby in a systems control protocol using HTTP, this type of error |
|  |  | recovery could lead to dangerous consequences. |
| 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]. |  | notation of [RFC5234]. |
| The following core rules are included by reference, as defined in |  | The following core rules are included by reference, as defined in |
| [RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF |  | [RFC5234], Appendix B.1: ALPHA (letters), CR (carriage return), CRLF |
| (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), |  | (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), |
| HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit |  | HEXDIG (hexadecimal 0-9/A-F/a-f), HTAB (horizontal tab), LF (line |
| sequence of data), SP (space), VCHAR (any visible [USASCII] |  | feed), OCTET (any 8-bit sequence of data), SP (space), and VCHAR (any |
| character), and WSP (whitespace). |  | visible [USASCII] character). |
| As a syntactic convention, ABNF rule names prefixed with "obs-" |  | As a syntactic convention, ABNF rule names prefixed with "obs-" |
| denote "obsolete" grammar rules that appear for historical reasons. |  | denote "obsolete" grammar rules that appear for historical reasons. |
| 1.2.1. ABNF Extension: #rule |  | 1.2.1. ABNF Extension: #rule |
| The #rule extension to the ABNF rules of [RFC5234] is used to improve |  | The #rule extension to the ABNF rules of [RFC5234] is used to improve |
| readability. |  | readability. |
| A construct "#" is defined, similar to "*", for defining comma- |  | A construct "#" is defined, similar to "*", for defining comma- |
| skipping to change at page 8, line 33 |  | skipping to change at page 8, line 47 |
| For example, given these ABNF productions: |  | For example, given these ABNF productions: |
| example-list = 1#example-list-elmt |  | example-list = 1#example-list-elmt |
| example-list-elmt = token ; see Section 3.2.3 |  | example-list-elmt = token ; see Section 3.2.3 |
| Then these are valid values for example-list (not including the |  | Then these are valid values for example-list (not including the |
| double quotes, which are present for delimitation only): |  | double quotes, which are present for delimitation only): |
| "foo,bar" |  | "foo,bar" |
| " foo ,bar," |  | "foo ,bar," |
| " foo , ,bar,charlie " |  | "foo , ,bar,charlie " |
| "foo ,bar, charlie " |  |  |
| But these values would be invalid, as at least one non-empty element |  | But these values would be invalid, as at least one non-empty element |
| is required: |  | is required: |
| "" |  | "" |
| "," |  | "," |
| ", ," |  | ", ," |
| Appendix B shows the collected ABNF, with the list rules expanded as |  | Appendix B shows the collected ABNF, with the list rules expanded as |
| explained above. |  | explained above. |
| skipping to change at page 9, line 9 |  | skipping to change at page 9, line 22 |
| 1.2.2. Basic Rules |  | 1.2.2. Basic Rules |
| This specification uses three rules to denote the use of linear |  | This specification uses three rules to denote the use of linear |
| whitespace: OWS (optional whitespace), RWS (required whitespace), and |  | whitespace: OWS (optional whitespace), RWS (required whitespace), and |
| BWS ("bad" whitespace). |  | BWS ("bad" whitespace). |
| The OWS rule is used where zero or more linear whitespace octets |  | The OWS rule is used where zero or more linear whitespace octets |
| might appear. OWS SHOULD either not be produced or be produced as a |  | might appear. OWS SHOULD either not be produced or be produced as a |
| single SP. Multiple OWS octets that occur within field-content |  | single SP. Multiple OWS octets that occur within field-content |
| 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 WSP 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 octets that occur within field-content SHOULD |  | Multiple RWS octets that occur within field-content SHOULD either be |
| either be replaced with a single SP or transformed to all SP octets |  | replaced with a single SP or transformed to all SP octets before |
| (each WSP octet other than SP replaced with SP) before interpreting |  | interpreting the field value or forwarding the message downstream. |
| 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 |  | HTTP/1.1 recipients MUST accept such bad optional whitespace and |
| remove it before interpreting the field value or forwarding the |  | remove it before interpreting the field value or forwarding the |
| message downstream. |  | message downstream. |
| OWS = *( [ obs-fold ] WSP ) |  | OWS = *( SP / HTAB / obs-fold ) |
| ; "optional" whitespace |  | ; "optional" whitespace |
| RWS = 1*( [ obs-fold ] WSP ) |  | RWS = 1*( SP / HTAB / obs-fold ) |
| ; "required" whitespace |  | ; "required" whitespace |
| BWS = OWS |  | BWS = OWS |
| ; "bad" whitespace |  | ; "bad" whitespace |
| obs-fold = CRLF |  | obs-fold = CRLF ( SP / HTAB ) |
| ; see Section 3.2 |  | ; obsolete line folding |
|  |  | ; see Section 3.2.1 |
| 2. HTTP-related architecture |  | 2. Architecture |
| 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 across a reliable transport or session-layer |  | exchanging messages (Section 3) across a reliable transport or |
| "connection". An HTTP "client" is a program that establishes a |  | session-layer "connection". An HTTP "client" is a program that |
| connection to a server for the purpose of sending one or more HTTP |  | establishes a connection to a server for the purpose of sending one |
| requests. An HTTP "server" is a program that accepts connections in |  | or more HTTP requests. An HTTP "server" is a program that accepts |
| order to service HTTP requests by sending HTTP responses. |  | connections in order to service HTTP requests by sending HTTP |
|  |  | responses. |
| Note that the terms client and server refer only to the roles that |  | Note that the terms client and server refer only to the roles that |
| these programs perform for a particular connection. The same program |  | these programs perform for a particular connection. The same program |
| might act as a client on some connections and a server on others. We |  | might 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 |  | use 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 10, line 24 |  | skipping to change at page 10, line 38 |
| representation of some resource identified by a URI. In the simplest |  | representation of some resource identified by a URI. In the simplest |
| case, this might be accomplished via a single bidirectional |  | case, this might be accomplished via a single bidirectional |
| connection (===) between the user agent (UA) and the origin server |  | connection (===) between the user agent (UA) and the origin server |
| (O). |  | (O). |
| request > |  | request > |
| UA ======================================= O |  | UA ======================================= O |
| < response |  | < response |
| A client sends an HTTP request to the server in the form of a request |  | A client sends an HTTP request to the server in the form of a request |
| message (Section 4), beginning with a method, URI, and protocol |  | message, beginning with a request-line that includes a method, URI, |
| version, followed by MIME-like header fields containing request |  | and protocol version (Section 3.1.1), followed by MIME-like header |
| modifiers, client information, and payload metadata, an empty line to |  | fields containing request modifiers, client information, and payload |
| indicate the end of the header section, and finally the payload body |  | metadata (Section 3.2), an empty line to indicate the end of the |
| (if any). |  | header section, and finally a message body containing the payload |
|  |  | body (if any, Section 3.3). |
| A server responds to the client's request by sending an HTTP response |  | A server responds to the client's request by sending an HTTP response |
| message (Section 5), beginning with a status line that includes the |  | message, beginning with a status line that includes the protocol |
| protocol version, a success or error code, and textual reason phrase, |  | version, a success or error code, and textual reason phrase |
| followed by MIME-like header fields containing server information, |  | (Section 3.1.2), followed by MIME-like header fields containing |
| resource metadata, and payload metadata, an empty line to indicate |  | server information, resource metadata, and payload metadata |
| the end of the header section, and finally the payload body (if any). |  | (Section 3.2), an empty line to indicate the end of the header |
|  |  | section, and finally a message body containing the payload body (if |
|  |  | any, Section 3.3). |
| The following example illustrates a typical message exchange for a |  | The following example illustrates a typical message exchange for a |
| GET request on the URI "http://www.example.com/hello.txt": |  | GET request on the URI "http://www.example.com/hello.txt": |
| client request: |  | client request: |
| GET /hello.txt HTTP/1.1 |  | GET /hello.txt HTTP/1.1 |
| User-Agent: curl/7.16.3 libcurl/7.16.3 OpenSSL/0.9.7l zlib/1.2.3 |  | User-Agent: curl/7.16.3 libcurl/7.16.3 OpenSSL/0.9.7l zlib/1.2.3 |
| Host: www.example.com |  | Host: www.example.com |
| Accept: */* |  | Accept: */* |
| skipping to change at page 11, line 22 |  | skipping to change at page 11, line 33 |
| Accept-Ranges: bytes |  | Accept-Ranges: bytes |
| Content-Length: 14 |  | Content-Length: 14 |
| Vary: Accept-Encoding |  | Vary: Accept-Encoding |
| Content-Type: text/plain |  | Content-Type: text/plain |
| Hello World! |  | Hello World! |
| 2.2. Message Orientation and Buffering |  | 2.2. Message Orientation and Buffering |
| Fundamentally, HTTP is a message-based protocol. Although message |  | Fundamentally, HTTP is a message-based protocol. Although message |
| bodies can be chunked (Section 6.2.1) and implementations often make |  | bodies can be chunked (Section 5.1.1) and implementations often make |
| parts of a message available progressively, this is not required, and |  | parts of a message available progressively, this is not required, and |
| some widely-used implementations only make a message available when |  | some widely-used implementations only make a message available when |
| it is complete. Furthermore, while most proxies will progressively |  | it is complete. Furthermore, while most proxies will progressively |
| stream messages, some amount of buffering will take place, and some |  | stream messages, some amount of buffering will take place, and some |
| proxies might buffer messages to perform transformations, check |  | proxies might buffer messages to perform transformations, check |
| content or provide other services. |  | content or provide other services. |
| Therefore, extensions to and uses of HTTP cannot rely on the |  | Therefore, extensions to and uses of HTTP cannot rely on the |
| availability of a partial message, or assume that messages will not |  | availability of a partial message, or assume that messages will not |
| be buffered. There are strategies that can be used to test for |  | be buffered. There are strategies that can be used to test for |
| skipping to change at page 12, line 14 |  | skipping to change at page 12, line 27 |
| protocol is outside the scope of this specification. |  | protocol is outside the scope of this specification. |
| The specific connection protocols to be used for an interaction are |  | The specific connection protocols to be used for an interaction are |
| determined by client configuration and the target resource's URI. |  | determined by client configuration and the target resource's URI. |
| For example, the "http" URI scheme (Section 2.7.1) indicates a |  | 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 |  | default connection of TCP over IP, with a default TCP port of 80, but |
| the client might be configured to use a proxy via some other |  | the client might be configured to use a proxy via some other |
| connection port or protocol instead of using the defaults. |  | connection port or protocol instead of using the defaults. |
| A connection might be used for multiple HTTP request/response |  | A connection might be used for multiple HTTP request/response |
| exchanges, as defined in Section 7.1. |  | exchanges, as defined in Section 6.1. |
| 2.4. Intermediaries |  | 2.4. Intermediaries |
| HTTP enables the use of intermediaries to satisfy requests through a |  | HTTP enables the use of intermediaries to satisfy requests through a |
| chain of connections. There are three common forms of HTTP |  | chain of connections. There are three common forms of HTTP |
| intermediary: proxy, gateway, and tunnel. In some cases, a single |  | intermediary: proxy, gateway, and tunnel. In some cases, a single |
| intermediary might act as an origin server, proxy, gateway, or |  | intermediary might act as an origin server, proxy, gateway, or |
| tunnel, switching behavior based on the nature of each request. |  | tunnel, switching behavior based on the nature of each request. |
| > > > > |  | > > > > |
| skipping to change at page 13, line 23 |  | skipping to change at page 13, line 36 |
| 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 8.2.4 of [Part2] and Section 3.6 of [Part6] |  | semantics. See Section 7.2.4 of [Part2] and Section 3.6 of [Part6] |
| for status and warning codes related to transformations. |  | for status and warning codes related to transformations. |
| A "gateway" (a.k.a., "reverse proxy") is a receiving agent that acts |  | A "gateway" (a.k.a., "reverse proxy") is a receiving agent that acts |
| as a layer above some other server(s) and translates the received |  | as a layer above some other server(s) and translates the received |
| requests to the underlying server's protocol. Gateways are often |  | requests to the underlying server's protocol. Gateways are often |
| used to encapsulate legacy or untrusted information services, to |  | used to encapsulate legacy or untrusted information services, to |
| improve server performance through "accelerator" caching, and to |  | improve server performance through "accelerator" caching, and to |
| enable partitioning or load-balancing of HTTP services across |  | enable partitioning or load-balancing of HTTP services across |
| multiple machines. |  | multiple machines. |
| skipping to change at page 13, line 40 |  | skipping to change at page 14, line 4 |
| 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 comply with HTTP user agent |  | third-party HTTP servers MUST comply with HTTP user agent |
| requirements on the gateway's inbound connection and MUST implement |  | requirements on the gateway's inbound connection and MUST implement |
| the Connection (Section 9.1) and Via (Section 9.9) header fields for |  | the Connection (Section 8.1) and Via (Section 8.8) header fields for |
| both connections. |  | both 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 is used to establish private communication |
| through a shared firewall proxy. |  | through a shared firewall proxy. |
| skipping to change at page 16, line 9 |  | skipping to change at page 16, line 20 |
| header fields ought to be implemented by all HTTP/1.x implementations |  | header fields ought to be implemented by all HTTP/1.x implementations |
| whether or not they advertise compliance with HTTP/1.1. |  | whether or not they advertise compliance with HTTP/1.1. |
| New header fields can be defined such that, when they are understood |  | New header fields can be defined such that, when they are understood |
| by a recipient, they might override or enhance the interpretation of |  | by a recipient, they might override or enhance the interpretation of |
| previously defined header fields. When an implementation receives an |  | previously defined header fields. When an implementation receives an |
| unrecognized header field, the recipient MUST ignore that header |  | unrecognized header field, the recipient MUST ignore that header |
| field for local processing regardless of the message's HTTP version. |  | field for local processing regardless of the message's HTTP version. |
| An unrecognized header field received by a proxy MUST be forwarded |  | An unrecognized header field received by a proxy MUST be forwarded |
| downstream unless the header field's field-name is listed in the |  | downstream unless the header field's field-name is listed in the |
| message's Connection header-field (see Section 9.1). These |  | message's Connection header-field (see Section 8.1). These |
| requirements allow HTTP's functionality to be enhanced without |  | requirements allow HTTP's functionality to be enhanced without |
| requiring prior update of all compliant intermediaries. |  | requiring prior update of all compliant intermediaries. |
| Intermediaries that process HTTP messages (i.e., all intermediaries |  | Intermediaries that process HTTP messages (i.e., all intermediaries |
| other than those acting as a tunnel) MUST send their own HTTP-Version |  | other than those acting as a tunnel) MUST send their own HTTP-Version |
| in forwarded messages. In other words, they MUST NOT blindly forward |  | in forwarded messages. In other words, they MUST NOT blindly forward |
| the first line of an HTTP message without ensuring that the protocol |  | the first line of an HTTP message without ensuring that the protocol |
| version matches what the intermediary understands, and is at least |  | version matches what the intermediary understands, and is at least |
| conditionally compliant to, for both the receiving and sending of |  | conditionally compliant to, for both the receiving and sending of |
| messages. Forwarding an HTTP message without rewriting the HTTP- |  | messages. Forwarding an HTTP message without rewriting the HTTP- |
| skipping to change at page 18, line 44 |  | skipping to change at page 19, line 6 |
| be running an HTTP server or listening to the indicated port. The |  | be running an HTTP server or listening to the indicated port. The |
| "http" URI scheme makes use of the delegated nature of Internet names |  | "http" URI scheme makes use of the delegated nature of Internet names |
| and addresses to establish a naming authority (whatever entity has |  | and addresses to establish a naming authority (whatever entity has |
| 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 to the |  | on the indicated port, and sending an HTTP request message |
| server containing the URI's identifying data as described in |  | (Section 3) containing the URI's identifying data (Section 4) to the |
| Section 4. 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 5, then that response |  | HTTP response message, as described in Section 4 of [Part2], then |
| is considered an authoritative answer to the client's request. |  | that response is considered an authoritative answer to the client's |
|  |  | 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 servers that require an SSL/TLS transport |
| layer on a connection. Other protocols might also be used to provide |  | layer on a 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. |
| skipping to change at page 20, line 43 |  | skipping to change at page 21, line 6 |
| http://EXAMPLE.com:/%7esmith/home.html |  | http://EXAMPLE.com:/%7esmith/home.html |
| 3. Message Format |  | 3. Message Format |
| All HTTP/1.1 messages consist of a start-line followed by a sequence |  | All HTTP/1.1 messages consist of a start-line followed by a sequence |
| of octets in a format similar to the Internet Message Format |  | of octets in a format similar to the Internet Message Format |
| [RFC5322]: zero or more header fields (collectively referred to as |  | [RFC5322]: zero or more header fields (collectively referred to as |
| the "headers" or the "header section"), an empty line indicating the |  | the "headers" or the "header section"), an empty line indicating the |
| end of the header section, and an optional message-body. |  | end of the header section, and an optional message-body. |
|  |  | HTTP-message = start-line |
|  |  | *( header-field CRLF ) |
|  |  | CRLF |
|  |  | [ message-body ] |
|  |  | The normal procedure for parsing an HTTP message is to read the |
|  |  | start-line into a structure, read each header field into a hash table |
|  |  | by field name until the empty line, and then use the parsed data to |
|  |  | determine if a message-body is expected. If a message-body has been |
|  |  | indicated, then it is read as a stream until an amount of octets |
|  |  | equal to the message-body length is read or the connection is closed. |
|  |  | Recipients MUST parse an HTTP message as a sequence of octets in an |
|  |  | encoding that is a superset of US-ASCII [USASCII]. Parsing an HTTP |
|  |  | message as a stream of Unicode characters, without regard for the |
|  |  | specific encoding, creates security vulnerabilities due to the |
|  |  | varying ways that string processing libraries handle invalid |
|  |  | multibyte character sequences that contain the octet LF (%x0A). |
|  |  | String-based parsers can only be safely used within protocol elements |
|  |  | after the element has been extracted from the message, such as within |
|  |  | a header field-value after message parsing has delineated the |
|  |  | individual fields. |
|  |  | 3.1. Start Line |
| An HTTP message can either be a request from client to server or a |  | An HTTP message can either be a request from client to server or a |
| response from server to client. Syntactically, the two types of |  | response from server to client. Syntactically, the two types of |
| message differ only in the start-line, which is either a Request-Line |  | message differ only in the start-line, which is either a Request-Line |
| (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. |
| HTTP-message = start-line |  |  |
| *( header-field CRLF ) |  |  |
| CRLF |  |  |
| [ message-body ] |  |  |
| start-line = Request-Line / Status-Line |  | start-line = Request-Line / Status-Line |
| Implementations MUST NOT send whitespace between the start-line and |  | Implementations MUST NOT send whitespace between the start-line and |
| the first header field. The presence of such whitespace in a request |  | the 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. Message Parsing and Robustness |  | 3.1.1. Request-Line |
| The normal procedure for parsing an HTTP message is to read the |  | The Request-Line begins with a method token, followed by a single |
| start-line into a structure, read each header field into a hash table |  | space (SP), the request-target, another single space (SP), the |
| by field name until the empty line, and then use the parsed data to |  | protocol version, and ending with CRLF. |
| determine if a message-body is expected. If a message-body has been |  |  |
| indicated, then it is read as a stream until an amount of octets |  |  |
| equal to the message-body length is read or the connection is closed. |  |  |
| Care must be taken to parse an HTTP message as a sequence of octets |  | Request-Line = Method SP request-target SP HTTP-Version CRLF |
| in an encoding that is a superset of US-ASCII. Attempting to parse |  |  |
| HTTP as a stream of Unicode characters in a character encoding like |  |  |
| UTF-16 might introduce security flaws due to the differing ways that |  |  |
| such parsers interpret invalid characters. |  |  |
| Older HTTP/1.0 client implementations might send an extra CRLF after |  | 3.1.1.1. Method |
| a POST request as a lame workaround for some early server |  |  |
| 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 |  |  |
| follow a request with an extra CRLF. If terminating the request |  |  |
| message-body with a line-ending is desired, then the client MUST |  |  |
| include the terminating CRLF octets as part of the message-body |  |  |
| length. |  |  |
| In the interest of robustness, servers SHOULD ignore at least one |  | The Method token indicates the request method to be performed on the |
| empty line received where a Request-Line is expected. In other |  | target resource. The request method is case-sensitive. |
| words, if the server is reading the protocol stream at the beginning |  |  |
| of a message and receives a CRLF first, it SHOULD ignore the CRLF. |  |  |
| Likewise, although the line terminator for the start-line and header |  |  |
| fields is the sequence CRLF, we recommend that recipients recognize a |  |  |
| single LF as a line terminator and ignore any CR. |  |  |
| When a server listening only for HTTP request messages, or processing |  | Method = token |
| what appears from the start-line to be an HTTP request message, |  |  |
| receives a sequence of octets that does not match the HTTP-message |  | See Section 2 of [Part2] for further information, such as the list of |
| grammar aside from the robustness exceptions listed above, the server |  | methods defined by this specification, the IANA registry, and |
| MUST respond with an HTTP/1.1 400 (Bad Request) response. |  | considerations for new methods. |
|  |  | 3.1.1.2. request-target |
|  |  | The request-target identifies the target resource upon which to apply |
|  |  | the request. The four options for request-target are described in |
|  |  | Section 4.1. |
|  |  | request-target = "*" |
|  |  | / absolute-URI |
|  |  | / ( path-absolute [ "?" query ] ) |
|  |  | / authority |
|  |  | HTTP does not place a pre-defined limit on the length of a request- |
|  |  | target. A server MUST be prepared to receive URIs of unbounded |
|  |  | length and respond with the 414 (URI Too Long) status code if the |
|  |  | received request-target would be longer than the server wishes to |
|  |  | handle (see Section 7.4.15 of [Part2]). |
|  |  | Various ad-hoc limitations on request-target length are found in |
|  |  | practice. It is RECOMMENDED that all HTTP senders and recipients |
|  |  | support request-target lengths of 8000 or more octets. |
|  |  | Note: Fragments ([RFC3986], Section 3.5) are not part of the |
|  |  | request-target and thus will not be transmitted in an HTTP |
|  |  | request. |
|  |  | 3.1.2. Response Status-Line |
|  |  | The first line of a Response message is the Status-Line, consisting |
|  |  | of the protocol version, a space (SP), the status code, another |
|  |  | space, a possibly-empty textual phrase describing the status code, |
|  |  | and ending with CRLF. |
|  |  | Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF |
|  |  | 3.1.2.1. Status Code |
|  |  | The Status-Code element is a 3-digit integer result code of the |
|  |  | attempt to understand and satisfy the request. See Section 4 of |
|  |  | [Part2] for further information, such as the list of status codes |
|  |  | defined by this specification, the IANA registry, and considerations |
|  |  | for new status codes. |
|  |  | Status-Code = 3DIGIT |
|  |  | 3.1.2.2. Reason Phrase |
|  |  | The Reason Phrase exists for the sole purpose of providing a textual |
|  |  | description associated with the numeric status code, out of deference |
|  |  | to earlier Internet application protocols that were more frequently |
|  |  | used with interactive text clients. A client SHOULD ignore the |
|  |  | content of the Reason Phrase. |
|  |  | Reason-Phrase = *( HTAB / SP / VCHAR / obs-text ) |
| 3.2. Header Fields |  | 3.2. Header Fields |
| Each HTTP header field consists of a case-insensitive field name |  | Each HTTP header field consists of a case-insensitive field name |
| followed by a colon (":"), optional whitespace, and the field value. |  | followed by a colon (":"), optional whitespace, and the field value. |
| header-field = field-name ":" OWS [ field-value ] OWS |  | header-field = field-name ":" OWS field-value BWS |
| field-name = token |  | field-name = token |
| field-value = *( field-content / OWS ) |  | field-value = *( field-content / obs-fold ) |
| field-content = *( WSP / VCHAR / obs-text ) |  | field-content = *( HTAB / SP / VCHAR / obs-text ) |
| 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 9.3 as containing the origination |  | header field is defined in Section 9.2 of [Part2] as containing the |
| timestamp for the message in which it appears. |  | origination timestamp for the message in which it appears. |
| HTTP header fields are fully extensible: there is no limit on the |  | HTTP header fields are fully extensible: there is no limit on the |
| introduction of new field names, each presumably defining new |  | introduction of new field names, each presumably defining new |
| semantics, or on the number of header fields used in a given message. |  | semantics, or on the number of header fields used in a given message. |
| Existing fields are defined in each part of this specification and in |  | Existing fields are defined in each part of this specification and in |
| many other specifications outside the standards process. New header |  | many other specifications outside the standards process. New header |
| fields can be introduced without changing the protocol version if |  | fields can be introduced without changing the protocol version if |
| their defined semantics allow them to be safely ignored by recipients |  | their defined semantics allow them to be safely ignored by recipients |
| that do not recognize them. |  | that do not recognize them. |
| New HTTP header fields SHOULD be registered with IANA according to |  | New HTTP header fields SHOULD be registered with IANA according to |
| the procedures in Section 10.1. Unrecognized header fields MUST be |  | the procedures in Section 3.1 of [Part2]. Unrecognized header fields |
| forwarded by a proxy unless the field-name is listed in the |  | MUST be forwarded by a proxy unless the field-name is listed in the |
| Connection header field (Section 9.1) or the proxy is specifically |  | Connection header field (Section 8.1) or the proxy is specifically |
| configured to block or otherwise transform such fields. Unrecognized |  | configured to block or otherwise transform such fields. Unrecognized |
| header fields SHOULD be ignored by other recipients. |  | 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 |
| skipping to change at page 23, line 38 |  | skipping to change at page 25, line 14 |
| A field value MAY be preceded by optional whitespace (OWS); a single |  | A field value MAY be preceded by optional whitespace (OWS); a single |
| SP is preferred. The field value does not include any leading or |  | SP is preferred. The field value does not include any leading or |
| trailing white space: OWS occurring before the first non-whitespace |  | trailing white space: OWS occurring before the first non-whitespace |
| octet of the field value or after the last non-whitespace octet of |  | octet of the field value or after the last non-whitespace octet of |
| the field value is ignored and SHOULD be removed before further |  | the field value is ignored and SHOULD be removed before further |
| processing (as this does not change the meaning of the header field). |  | processing (as this does not change the meaning of the header field). |
| Historically, HTTP header field values could be extended over |  | Historically, HTTP header field values could be extended over |
| multiple lines by preceding each extra line with at least one space |  | multiple lines by preceding each extra line with at least one space |
| or horizontal tab octet (line folding). This specification |  | or horizontal tab (obs-fold). This specification deprecates such |
| deprecates such line folding except within the message/http media |  | line folding except within the message/http media type |
| type (Section 10.3.1). HTTP senders MUST NOT produce messages that |  | (Section 9.3.1). HTTP senders MUST NOT produce messages that include |
| include line folding (i.e., that contain any field-content that |  | line folding (i.e., that contain any field-content that matches the |
| matches the obs-fold rule) unless the message is intended for |  | obs-fold rule) unless the message is intended for packaging within |
| packaging within the message/http media type. HTTP recipients SHOULD |  | the message/http media type. HTTP recipients SHOULD accept line |
| accept line folding and replace any embedded obs-fold whitespace with |  | folding and replace any embedded obs-fold whitespace with either a |
| either a single SP or a matching number of SP octets (to avoid buffer |  | single SP or a matching number of SP octets (to avoid buffer copying) |
| copying) prior to interpreting the field value or forwarding the |  | prior to interpreting the field value or forwarding the message |
| message downstream. |  | downstream. |
| Historically, HTTP has allowed field content with text in the ISO- |  | Historically, HTTP has allowed field content with text in the ISO- |
| 8859-1 [ISO-8859-1] character encoding and supported other character |  | 8859-1 [ISO-8859-1] character encoding and supported other character |
| sets only through use of [RFC2047] encoding. In practice, most HTTP |  | sets only through use of [RFC2047] encoding. In practice, most HTTP |
| header field values use only a subset of the US-ASCII character |  | header field values use only a subset of the US-ASCII character |
| encoding [USASCII]. Newly defined header fields SHOULD limit their |  | encoding [USASCII]. Newly defined header fields SHOULD limit their |
| field values to US-ASCII octets. Recipients SHOULD treat other (obs- |  | field values to US-ASCII octets. Recipients SHOULD treat other (obs- |
| text) octets in field content as opaque data. |  | text) octets in field content as opaque data. |
| 3.2.2. Field Length |  | 3.2.2. Field Length |
| skipping to change at page 24, line 29 |  | skipping to change at page 26, line 4 |
| Various ad-hoc limitations on header length are found in practice. |  | Various ad-hoc limitations on header length are found in practice. |
| It is RECOMMENDED that all HTTP senders and recipients support |  | It is RECOMMENDED that all HTTP senders and recipients support |
| messages whose combined header fields have 4000 or more octets. |  | messages whose combined header fields have 4000 or more octets. |
| 3.2.3. Common Field ABNF Rules |  | 3.2.3. Common Field ABNF Rules |
| Many HTTP/1.1 header field values consist of words (token or quoted- |  | Many HTTP/1.1 header field values consist of words (token or quoted- |
| string) separated by whitespace or special characters. These special |  | string) separated by whitespace or special characters. These special |
| characters MUST be in a quoted string to be used within a parameter |  | characters MUST be in a quoted string to be used within a parameter |
| value (as defined in Section 6.2). |  | value (as defined in Section 5.1). |
| word = token / quoted-string |  | word = token / quoted-string |
| token = 1*tchar |  | token = 1*tchar |
| tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" |  | tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" |
| / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~" |  | / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~" |
| / DIGIT / ALPHA |  | / DIGIT / ALPHA |
| ; any VCHAR, except special |  | ; any VCHAR, except special |
| skipping to change at page 25, line 6 |  | skipping to change at page 26, line 29 |
| A string of text is parsed as a single word if it is quoted using |  | A string of text is parsed as a single word if it is quoted using |
| double-quote marks. |  | double-quote marks. |
| quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE |  | quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE |
| qdtext = OWS / %x21 / %x23-5B / %x5D-7E / obs-text |  | qdtext = OWS / %x21 / %x23-5B / %x5D-7E / obs-text |
| obs-text = %x80-FF |  | obs-text = %x80-FF |
| The backslash octet ("\") can be used as a single-octet quoting |  | The backslash octet ("\") can be used as a single-octet quoting |
| mechanism within quoted-string constructs: |  | mechanism within quoted-string constructs: |
| quoted-pair = "\" ( WSP / VCHAR / obs-text ) |  | quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text ) |
| Recipients that process the value of the quoted-string MUST handle a |  | Recipients that process the value of the quoted-string MUST handle a |
| quoted-pair as if it were replaced by the octet following the |  | quoted-pair as if it were replaced by the octet following the |
| backslash. |  | backslash. |
| Senders SHOULD NOT escape octets in quoted-strings that do not |  | Senders SHOULD NOT escape octets in quoted-strings that do not |
| require escaping (i.e., other than DQUOTE and the backslash octet). |  | require escaping (i.e., other than DQUOTE and the backslash octet). |
| Comments can be included in some HTTP header fields by surrounding |  | Comments can be included in some HTTP header fields by surrounding |
| the comment text with parentheses. Comments are only allowed in |  | the comment text with parentheses. Comments are only allowed in |
| fields containing "comment" as part of their field value definition. |  | fields containing "comment" as part of their field value definition. |
| comment = "(" *( ctext / quoted-cpair / comment ) ")" |  | comment = "(" *( ctext / quoted-cpair / comment ) ")" |
| ctext = OWS / %x21-27 / %x2A-5B / %x5D-7E / obs-text |  | ctext = OWS / %x21-27 / %x2A-5B / %x5D-7E / obs-text |
| The backslash octet ("\") can be used as a single-octet quoting |  | The backslash octet ("\") can be used as a single-octet quoting |
| mechanism within comment constructs: |  | mechanism within comment constructs: |
| quoted-cpair = "\" ( WSP / VCHAR / obs-text ) |  | quoted-cpair = "\" ( HTAB / SP / VCHAR / obs-text ) |
| Senders SHOULD NOT escape octets in comments that do not require |  | Senders SHOULD NOT escape octets in comments that do not require |
| escaping (i.e., other than the backslash octet "\" and the |  | escaping (i.e., other than the backslash octet "\" and the |
| parentheses "(" and ")"). |  | parentheses "(" and ")"). |
| 3.3. Message Body |  | 3.3. Message Body |
| The message-body (if any) of an HTTP message is used to carry the |  | The message-body (if any) of an HTTP message is used to carry the |
| payload body associated with the request or response. |  | payload body associated with the request or response. |
| message-body = *OCTET |  | message-body = *OCTET |
| The message-body differs from the payload body only when a transfer- |  | The message-body differs from the payload body only when a transfer- |
| coding has been applied, as indicated by the Transfer-Encoding header |  | coding has been applied, as indicated by the Transfer-Encoding header |
| field (Section 9.7). If more than one Transfer-Encoding header field |  | field (Section 8.6). If more than one Transfer-Encoding header field |
| is present in a message, the multiple field-values MUST be combined |  | is present in a message, the multiple field-values MUST be combined |
| into one field-value, according to the algorithm defined in |  | into one field-value, according to the algorithm defined in |
| Section 3.2, before determining the message-body length. |  | Section 3.2, before determining the message-body length. |
| When one or more transfer-codings are applied to a payload in order |  | When one or more transfer-codings are applied to a payload in order |
| to form the message-body, the Transfer-Encoding header field MUST |  | to form the message-body, the Transfer-Encoding header field MUST |
| contain the list of transfer-codings applied. Transfer-Encoding is a |  | contain the list of transfer-codings applied. Transfer-Encoding is a |
| property of the message, not of the payload, and thus MAY be added or |  | property of the message, not of the payload, and thus MAY be added or |
| removed by any implementation along the request/response chain under |  | removed by any implementation along the request/response chain under |
| the constraints found in Section 6.2. |  | the constraints found in Section 5.1. |
| If a message is received that has multiple Content-Length header |  | If a message is received that has multiple Content-Length header |
| fields (Section 9.2) with field-values consisting of the same decimal |  | fields (Section 8.2) with field-values consisting of the same decimal |
| value, or a single Content-Length header field with a field value |  | value, or a single Content-Length header field with a field value |
| containing a list of identical decimal values (e.g., "Content-Length: |  | containing a list of identical decimal values (e.g., "Content-Length: |
| 42, 42"), indicating that duplicate Content-Length header fields have |  | 42, 42"), indicating that duplicate Content-Length header fields have |
| been generated or combined by an upstream message processor, then the |  | been generated or combined by an upstream message processor, then the |
| recipient MUST either reject the message as invalid or replace the |  | recipient MUST either reject the message as invalid or replace the |
| duplicated field-values with a single valid Content-Length field |  | duplicated field-values with a single valid Content-Length field |
| containing that decimal value prior to determining the message-body |  | containing that decimal value prior to determining the message-body |
| length. |  | length. |
| The rules for when a message-body is allowed in a message differ for |  | The rules for when a message-body is allowed in a message differ for |
| requests and responses. |  | requests and responses. |
| The presence of a message-body in a request is signaled by the |  | The presence of a message-body in a request is signaled by the |
| inclusion of a Content-Length or Transfer-Encoding header field in |  | inclusion of a Content-Length or Transfer-Encoding header field in |
| the request's header fields, even if the request method does not |  | the request's header fields, even if the request method does not |
| define any use for a message-body. This allows the request message |  | define any use for a message-body. This allows the request message |
| framing algorithm to be independent of method semantics. |  | framing algorithm to be independent of method semantics. |
| For response messages, whether or not a message-body is included with |  | For response messages, whether or not a message-body is included with |
| a message is dependent on both the request method and the response |  | a message is dependent on both the request method and the response |
| status code (Section 5.1.1). Responses to the HEAD request method |  | status code (Section 3.1.2.1). Responses to the HEAD request method |
| never include a message-body because the associated response header |  | never include a message-body because the associated response header |
| fields (e.g., Transfer-Encoding, Content-Length, etc.) only indicate |  | fields (e.g., Transfer-Encoding, Content-Length, etc.) only indicate |
| what their values would have been if the request method had been GET. |  | what their values would have been if the request method had been GET. |
| All 1xx (Informational), 204 (No Content), and 304 (Not Modified) |  | All 1xx (Informational), 204 (No Content), and 304 (Not Modified) |
| responses MUST NOT include a message-body. All other responses do |  | responses MUST NOT include a message-body. All other responses do |
| include a message-body, although the body MAY be of zero length. |  | include a message-body, although the body MAY be of zero length. |
| The length of the message-body is determined by one of the following |  | The length of the message-body is determined by one of the following |
| (in order of precedence): |  | (in order of precedence): |
| 1. Any response to a HEAD request and any response with a status |  | 1. Any response to a HEAD request and any response with a status |
| code of 100-199, 204, or 304 is always terminated by the first |  | code of 100-199, 204, or 304 is always terminated by the first |
| empty line after the header fields, regardless of the header |  | empty line after the header fields, regardless of the header |
| fields present in the message, and thus cannot contain a message- |  | fields present in the message, and thus cannot contain a message- |
| body. |  | body. |
| 2. If a Transfer-Encoding header field is present and the "chunked" |  | 2. If a Transfer-Encoding header field is present and the "chunked" |
| transfer-coding (Section 6.2) is the final encoding, the message- |  | transfer-coding (Section 5.1) is the final encoding, the message- |
| body length is determined by reading and decoding the chunked |  | body length is determined by reading and decoding the chunked |
| data until the transfer-coding indicates the data is complete. |  | data until the transfer-coding indicates the data is complete. |
| If a Transfer-Encoding header field is present in a response and |  | If a Transfer-Encoding header field is present in a response and |
| the "chunked" transfer-coding is not the final encoding, the |  | the "chunked" transfer-coding is not the final encoding, the |
| message-body length is determined by reading the connection until |  | message-body length is determined by reading the connection until |
| it is closed by the server. If a Transfer-Encoding header field |  | it is closed by the server. If a Transfer-Encoding header field |
| is present in a request and the "chunked" transfer-coding is not |  | is present in a request and the "chunked" transfer-coding is not |
| the final encoding, the message-body length cannot be determined |  | the final encoding, the message-body length cannot be determined |
| reliably; the server MUST respond with the 400 (Bad Request) |  | reliably; the server MUST respond with the 400 (Bad Request) |
| skipping to change at page 28, line 36 |  | skipping to change at page 30, line 9 |
| requires a content-length in advance of being called and the server |  | requires a content-length in advance of being called and the server |
| is unable or unwilling to buffer the entire request before |  | is unable or unwilling to buffer the entire request before |
| processing. |  | processing. |
| 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. Incomplete Messages |  | 3.4. Handling Incomplete Messages |
| Request messages that are prematurely terminated, possibly due to a |  | Request messages that are prematurely terminated, possibly due to a |
| cancelled connection or a server-imposed time-out exception, MUST |  | cancelled connection or a server-imposed time-out exception, MUST |
| result in closure of the connection; sending an HTTP/1.1 error |  | result in closure of the connection; sending an HTTP/1.1 error |
| response prior to closing the connection is OPTIONAL. |  | response prior to closing the connection is OPTIONAL. |
| Response messages that are prematurely terminated, usually by closure |  | Response messages that are prematurely terminated, usually by closure |
| of the connection prior to receiving the expected number of octets or |  | of the connection prior to receiving the expected number of octets or |
| by failure to decode a transfer-encoded message-body, MUST be |  | by failure to decode a transfer-encoded message-body, MUST be |
| recorded as incomplete. A response that terminates in the middle of |  | recorded as incomplete. A response that terminates in the middle of |
| skipping to change at page 29, line 23 |  | skipping to change at page 30, line 45 |
| if it were complete (i.e., some indication must be given to the user |  | if it were complete (i.e., some indication must be given to the user |
| that an error occurred). Cache requirements for incomplete responses |  | that an error occurred). Cache requirements for incomplete responses |
| are defined in Section 2.1 of [Part6]. |  | are defined in Section 2.1 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 7.1.2.2. |  | in Section 6.1.2.2. |
| 3.5. General Header Fields |  |  |
| There are a few header fields which have general applicability for |  |  |
| both request and response messages, but which do not apply to the |  |  |
| payload being transferred. These header fields apply only to the |  |  |
| message being transmitted. |  |  |
| +-------------------+---------------+ |  |  |
| | Header Field Name | Defined in... | |  |  |
| +-------------------+---------------+ |  |  |
| | Connection | Section 9.1 | |  |  |
| | Date | Section 9.3 | |  |  |
| | Trailer | Section 9.6 | |  |  |
| | Transfer-Encoding | Section 9.7 | |  |  |
| | Upgrade | Section 9.8 | |  |  |
| | Via | Section 9.9 | |  |  |
| +-------------------+---------------+ |  |  |
| 4. Request |  |  |
| A request message from a client to a server begins with a Request- |  |  |
| Line, followed by zero or more header fields, an empty line |  |  |
| signifying the end of the header block, and an optional message body. |  |  |
| Request = Request-Line ; Section 4.1 |  |  |
| *( header-field CRLF ) ; Section 3.2 |  |  |
| CRLF |  |  |
| [ message-body ] ; Section 3.3 |  |  |
| 4.1. Request-Line |  |  |
| The Request-Line begins with a method token, followed by a single |  |  |
| space (SP), the request-target, another single space (SP), the |  |  |
| protocol version, and ending with CRLF. |  |  |
| Request-Line = Method SP request-target SP HTTP-Version CRLF |  | 3.5. Message Parsing Robustness |
| 4.1.1. Method |  | Older HTTP/1.0 client implementations might send an extra CRLF after |
|  |  | a POST request as a lame workaround for some early server |
|  |  | 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 |
|  |  | follow a request with an extra CRLF. If terminating the request |
|  |  | message-body with a line-ending is desired, then the client MUST |
|  |  | include the terminating CRLF octets as part of the message-body |
|  |  | length. |
| The Method token indicates the request method to be performed on the |  | In the interest of robustness, servers SHOULD ignore at least one |
| target resource. The request method is case-sensitive. |  | empty line received where a Request-Line is expected. In other |
|  |  | words, if the server is reading the protocol stream at the beginning |
|  |  | of a message and receives a CRLF first, it SHOULD ignore the CRLF. |
|  |  | Likewise, although the line terminator for the start-line and header |
|  |  | fields is the sequence CRLF, we recommend that recipients recognize a |
|  |  | single LF as a line terminator and ignore any CR. |
| Method = token |  | When a server listening only for HTTP request messages, or processing |
|  |  | what appears from the start-line to be an HTTP request message, |
|  |  | receives a sequence of octets that does not match the HTTP-message |
|  |  | grammar aside from the robustness exceptions listed above, the server |
|  |  | MUST respond with an HTTP/1.1 400 (Bad Request) response. |
| 4.1.2. request-target |  | 4. Message Routing |
| The request-target identifies the target resource upon which to apply |  | In most cases, the user agent is provided a URI reference from which |
| the request. In most cases, the user agent is provided a URI |  | it determines an absolute URI for identifying the target resource. |
| reference from which it determines an absolute URI for identifying |  | When a request to the resource is initiated, all or part of that URI |
| the target resource. When a request to the resource is initiated, |  | is used to construct the HTTP request-target. |
| all or part of that URI is used to construct the HTTP request-target. |  |  |
| request-target = "*" |  | 4.1. Types of Request Target |
| / absolute-URI |  |  |
| / ( path-absolute [ "?" query ] ) |  |  |
| / authority |  |  |
| The four options for request-target are dependent on the nature of |  | The four options for request-target are dependent on the nature of |
| the request. |  | the request. |
| The asterisk "*" form of request-target, which MUST NOT be used with |  | The asterisk "*" form of request-target, which MUST NOT be used with |
| any request method other than OPTIONS, means that the request applies |  | any request method other than OPTIONS, means that the request applies |
| to the server as a whole (the listening process) rather than to a |  | to the server as a whole (the listening process) rather than to a |
| specific named resource at that server. For example, |  | specific named resource at that server. For example, |
| OPTIONS * HTTP/1.1 |  | OPTIONS * HTTP/1.1 |
| skipping to change at page 31, line 20 |  | skipping to change at page 32, line 18 |
| versions of HTTP, all HTTP/1.1 servers MUST accept the absolute-URI |  | versions of HTTP, all HTTP/1.1 servers MUST accept the absolute-URI |
| form in requests, even though HTTP/1.1 clients will only generate |  | form in requests, even though HTTP/1.1 clients will only generate |
| them in requests to proxies. |  | them in requests to proxies. |
| If a proxy receives a host name that is not a fully qualified domain |  | If a proxy receives a host name that is not a fully qualified domain |
| name, it MAY add its domain to the host name it received. If a proxy |  | name, it MAY add its domain to the host name it received. If a proxy |
| receives a fully qualified domain name, the proxy MUST NOT change the |  | receives a fully qualified domain name, the proxy MUST NOT change the |
| host name. |  | host name. |
| The "authority form" is only used by the CONNECT request method |  | The "authority form" is only used by the CONNECT request method |
| (Section 7.9 of [Part2]). |  | (Section 6.9 of [Part2]). |
| The most common form of request-target is that used when making a |  | The most common form of request-target is that used when making a |
| request to an origin server ("origin form"). In this case, the |  | request to an origin server ("origin form"). In this case, the |
| absolute path and query components of the URI MUST be transmitted as |  | absolute path and query components of the URI MUST be transmitted as |
| the request-target, and the authority component MUST be transmitted |  | the request-target, and the authority component MUST be transmitted |
| in a Host header field. For example, a client wishing to retrieve a |  | in a Host header field. For example, a client wishing to retrieve a |
| representation of the resource, as identified above, directly from |  | representation of the resource, as identified above, directly from |
| the origin server would open (or reuse) a TCP connection to port 80 |  | the origin server would open (or reuse) a TCP connection to port 80 |
| of the host "www.example.org" and send the lines: |  | of the host "www.example.org" and send the lines: |
| skipping to change at page 32, line 29 |  | skipping to change at page 33, line 29 |
| the received request-target when forwarding it to the next inbound |  | the received request-target when forwarding it to the next inbound |
| server, except as noted above to replace a null path-absolute with |  | server, except as noted above to replace a null path-absolute with |
| "/" or "*". |  | "/" or "*". |
| Note: The "no rewrite" rule prevents the proxy from changing the |  | Note: The "no rewrite" rule prevents the proxy from changing the |
| meaning of the request when the origin server is improperly using |  | meaning of the request when the origin server is improperly using |
| a non-reserved URI character for a reserved purpose. Implementors |  | a non-reserved URI character for a reserved purpose. Implementors |
| need to be aware that some pre-HTTP/1.1 proxies have been known to |  | need to be aware that some pre-HTTP/1.1 proxies have been known to |
| rewrite the request-target. |  | rewrite the request-target. |
| HTTP does not place a pre-defined limit on the length of a request- |  |  |
| target. A server MUST be prepared to receive URIs of unbounded |  |  |
| length and respond with the 414 (URI Too Long) status code if the |  |  |
| received request-target would be longer than the server wishes to |  |  |
| handle (see Section 8.4.15 of [Part2]). |  |  |
| Various ad-hoc limitations on request-target length are found in |  |  |
| practice. It is RECOMMENDED that all HTTP senders and recipients |  |  |
| support request-target lengths of 8000 or more octets. |  |  |
| Note: Fragments ([RFC3986], Section 3.5) are not part of the |  |  |
| request-target and thus will not be transmitted in an HTTP |  |  |
| request. |  |  |
| 4.2. The Resource Identified by a Request |  | 4.2. The Resource Identified by a Request |
| The exact resource identified by an Internet request is determined by |  | The exact resource identified by an Internet request is determined by |
| examining both the request-target and the Host header field. |  | examining both the request-target and the Host header field. |
| An origin server that does not allow resources to differ by the |  | An origin server that does not allow resources to differ by the |
| requested host MAY ignore the Host header field value when |  | requested host MAY ignore the Host header field value when |
| determining the resource identified by an HTTP/1.1 request. (But see |  | determining the resource identified by an HTTP/1.1 request. (But see |
| Appendix A.1.1 for other requirements on Host support in HTTP/1.1.) |  | Appendix A.1.1 for other requirements on Host support in HTTP/1.1.) |
| An origin server that does differentiate resources based on the host |  | An origin server that does differentiate resources based on the host |
| requested (sometimes referred to as virtual hosts or vanity host |  | requested (sometimes referred to as virtual hosts or vanity host |
| names) MUST use the following rules for determining the requested |  | names) MUST use the following rules for determining the requested |
| resource on an HTTP/1.1 request: |  | resource on an HTTP/1.1 request: |
| 1. If request-target is an absolute-URI, the host is part of the |  | 1. If request-target is an absolute-URI, the host is part of the |
| request-target. Any Host header field value in the request MUST |  | request-target. Any Host header field value in the request MUST |
| be ignored. |  | be ignored. |
| 2. If the request-target is not an absolute-URI, and the request |  | 2. If the request-target is not an absolute-URI, and the request |
| skipping to change at page 33, line 49 |  | skipping to change at page 34, line 37 |
| form, and the Host header field is present, then the effective |  | form, and the Host header field is present, then the effective |
| request URI is constructed by concatenating |  | request URI is constructed by concatenating |
| o the scheme name: "http" if the request was received over an |  | o the scheme name: "http" if the request was received over an |
| insecure TCP connection, or "https" when received over a SSL/ |  | insecure TCP connection, or "https" when received over a SSL/ |
| TLS-secured TCP connection, |  | TLS-secured TCP connection, |
| o the octet sequence "://", |  | o the octet sequence "://", |
| o the authority component, as specified in the Host header field |  | o the authority component, as specified in the Host header field |
| (Section 9.4), and |  | (Section 8.3), and |
| o the request-target obtained from the Request-Line, unless the |  | o the request-target obtained from the Request-Line, unless the |
| request-target is just the asterisk "*". |  | request-target is just the asterisk "*". |
| If the request-target uses the path-absolute form or the asterisk |  | If the request-target uses the path-absolute form or the asterisk |
| form, and the Host header field is not present, then the effective |  | form, and the Host header field is not present, then the effective |
| request URI is undefined. |  | request URI is undefined. |
| Otherwise, when request-target uses the authority form, the effective |  | Otherwise, when request-target uses the authority form, the effective |
| request URI is undefined. |  | request URI is undefined. |
| skipping to change at page 34, line 38 |  | skipping to change at page 35, line 28 |
| Host: www.example.org |  | Host: www.example.org |
| (received over an SSL/TLS secured TCP connection) is "https", plus |  | (received over an SSL/TLS secured TCP connection) is "https", plus |
| "://", plus the authority component "www.example.org", thus |  | "://", plus the authority component "www.example.org", thus |
| "https://www.example.org". |  | "https://www.example.org". |
| Effective request URIs are compared using the rules described in |  | Effective request URIs are compared using the rules described in |
| Section 2.7.3, except that empty path components MUST NOT be treated |  | Section 2.7.3, except that empty path components MUST NOT be treated |
| as equivalent to an absolute path of "/". |  | as equivalent to an absolute path of "/". |
| 5. Response |  | 5. Protocol Parameters |
| After receiving and interpreting a request message, a server responds |  |  |
| with an HTTP response message. |  |  |
| Response = Status-Line ; Section 5.1 |  |  |
| *( header-field CRLF ) ; Section 3.2 |  |  |
| CRLF |  |  |
| [ message-body ] ; Section 3.3 |  |  |
| 5.1. Status-Line |  |  |
| The first line of a Response message is the Status-Line, consisting |  |  |
| of the protocol version, a space (SP), the status code, another |  |  |
| space, a possibly-empty textual phrase describing the status code, |  |  |
| and ending with CRLF. |  |  |
| Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF |  |  |
| 5.1.1. Status Code and Reason Phrase |  |  |
| The Status-Code element is a 3-digit integer result code of the |  |  |
| attempt to understand and satisfy the request. These codes are fully |  |  |
| defined in Section 8 of [Part2]. The Reason Phrase exists for the |  |  |
| sole purpose of providing a textual description associated with the |  |  |
| numeric status code, out of deference to earlier Internet application |  |  |
| protocols that were more frequently used with interactive text |  |  |
| clients. A client SHOULD ignore the content of the Reason Phrase. |  |  |
| The first digit of the Status-Code defines the class of response. |  |  |
| The last two digits do not have any categorization role. There are 5 |  |  |
| values for the first digit: |  |  |
| o 1xx: Informational - Request received, continuing process |  |  |
| o 2xx: Success - The action was successfully received, understood, |  |  |
| and accepted |  |  |
| o 3xx: Redirection - Further action must be taken in order to |  |  |
| complete the request |  |  |
| o 4xx: Client Error - The request contains bad syntax or cannot be |  |  |
| fulfilled |  |  |
| o 5xx: Server Error - The server failed to fulfill an apparently |  |  |
| valid request |  |  |
| Status-Code = 3DIGIT |  |  |
| Reason-Phrase = *( WSP / VCHAR / obs-text ) |  |  |
| 6. Protocol Parameters |  |  |
| 6.1. Date/Time Formats: Full Date |  |  |
| HTTP applications have historically allowed three different formats |  |  |
| for date/time stamps. However, the preferred format is a fixed- |  |  |
| length subset of that defined by [RFC1123]: |  |  |
| Sun, 06 Nov 1994 08:49:37 GMT ; RFC 1123 |  |  |
| The other formats are described here only for compatibility with |  |  |
| obsolete implementations. |  |  |
| Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format |  |  |
| Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format |  |  |
| HTTP/1.1 clients and servers that parse a date value MUST accept all |  |  |
| three formats (for compatibility with HTTP/1.0), though they MUST |  |  |
| only generate the RFC 1123 format for representing HTTP-date values |  |  |
| in header fields. |  |  |
| All HTTP date/time stamps MUST be represented in Greenwich Mean Time |  |  |
| (GMT), without exception. For the purposes of HTTP, GMT is exactly |  |  |
| equal to UTC (Coordinated Universal Time). This is indicated in the |  |  |
| first two formats by the inclusion of "GMT" as the three-letter |  |  |
| abbreviation for time zone, and MUST be assumed when reading the |  |  |
| asctime format. HTTP-date is case sensitive and MUST NOT include |  |  |
| additional whitespace beyond that specifically included as SP in the |  |  |
| grammar. |  |  |
| HTTP-date = rfc1123-date / obs-date |  |  |
| Preferred format: |  |  |
| rfc1123-date = day-name "," SP date1 SP time-of-day SP GMT |  |  |
| ; fixed length subset of the format defined in |  |  |
| ; Section 5.2.14 of [RFC1123] |  |  |
| day-name = %x4D.6F.6E ; "Mon", case-sensitive |  |  |
| / %x54.75.65 ; "Tue", case-sensitive |  |  |
| / %x57.65.64 ; "Wed", case-sensitive |  |  |
| / %x54.68.75 ; "Thu", case-sensitive |  |  |
| / %x46.72.69 ; "Fri", case-sensitive |  |  |
| / %x53.61.74 ; "Sat", case-sensitive |  |  |
| / %x53.75.6E ; "Sun", case-sensitive |  |  |
| date1 = day SP month SP year |  |  |
| ; e.g., 02 Jun 1982 |  |  |
| day = 2DIGIT |  |  |
| month = %x4A.61.6E ; "Jan", case-sensitive |  |  |
| / %x46.65.62 ; "Feb", case-sensitive |  |  |
| / %x4D.61.72 ; "Mar", case-sensitive |  |  |
| / %x41.70.72 ; "Apr", case-sensitive |  |  |
| / %x4D.61.79 ; "May", case-sensitive |  |  |
| / %x4A.75.6E ; "Jun", case-sensitive |  |  |
| / %x4A.75.6C ; "Jul", case-sensitive |  |  |
| / %x41.75.67 ; "Aug", case-sensitive |  |  |
| / %x53.65.70 ; "Sep", case-sensitive |  |  |
| / %x4F.63.74 ; "Oct", case-sensitive |  |  |
| / %x4E.6F.76 ; "Nov", case-sensitive |  |  |
| / %x44.65.63 ; "Dec", case-sensitive |  |  |
| year = 4DIGIT |  |  |
| GMT = %x47.4D.54 ; "GMT", case-sensitive |  |  |
| time-of-day = hour ":" minute ":" second |  |  |
| ; 00:00:00 - 23:59:59 |  |  |
| hour = 2DIGIT |  |  |
| minute = 2DIGIT |  |  |
| second = 2DIGIT |  |  |
| The semantics of day-name, day, month, year, and time-of-day are the |  |  |
| same as those defined for the RFC 5322 constructs with the |  |  |
| corresponding name ([RFC5322], Section 3.3). |  |  |
| Obsolete formats: |  |  |
| obs-date = rfc850-date / asctime-date |  |  |
| rfc850-date = day-name-l "," SP date2 SP time-of-day SP GMT |  |  |
| date2 = day "-" month "-" 2DIGIT |  |  |
| ; day-month-year (e.g., 02-Jun-82) |  |  |
| day-name-l = %x4D.6F.6E.64.61.79 ; "Monday", case-sensitive |  |  |
| / %x54.75.65.73.64.61.79 ; "Tuesday", case-sensitive |  |  |
| / %x57.65.64.6E.65.73.64.61.79 ; "Wednesday", case-sensitive |  |  |
| / %x54.68.75.72.73.64.61.79 ; "Thursday", case-sensitive |  |  |
| / %x46.72.69.64.61.79 ; "Friday", case-sensitive |  |  |
| / %x53.61.74.75.72.64.61.79 ; "Saturday", case-sensitive |  |  |
| / %x53.75.6E.64.61.79 ; "Sunday", case-sensitive |  |  |
| asctime-date = day-name SP date3 SP time-of-day SP year |  |  |
| date3 = month SP ( 2DIGIT / ( SP 1DIGIT )) |  |  |
| ; month day (e.g., Jun 2) |  |  |
| Note: Recipients of date values are encouraged to be robust in |  |  |
| accepting date values that might have been sent by non-HTTP |  |  |
| applications, as is sometimes the case when retrieving or posting |  |  |
| messages via proxies/gateways to SMTP or NNTP. |  |  |
| Note: HTTP requirements for the date/time stamp format apply only |  |  |
| to their usage within the protocol stream. Clients and servers |  |  |
| are not required to use these formats for user presentation, |  |  |
| request logging, etc. |  |  |
| 6.2. Transfer Codings |  | 5.1. Transfer Codings |
| Transfer-coding values are used to indicate an encoding |  | Transfer-coding values are used to indicate an encoding |
| transformation that has been, can be, or might need to be applied to |  | transformation that has been, can be, or might need to be applied to |
| a payload body in order to ensure "safe transport" through the |  | a payload body in order to ensure "safe transport" through the |
| network. This differs from a content coding in that the transfer- |  | network. This differs from a content coding in that the transfer- |
| coding is a property of the message rather than a property of the |  | coding is a property of the message rather than a property of the |
| representation that is being transferred. |  | representation that is being transferred. |
| transfer-coding = "chunked" ; Section 6.2.1 |  | transfer-coding = "chunked" ; Section 5.1.1 |
| / "compress" ; Section 6.2.2.1 |  | / "compress" ; Section 5.1.2.1 |
| / "deflate" ; Section 6.2.2.2 |  | / "deflate" ; Section 5.1.2.2 |
| / "gzip" ; Section 6.2.2.3 |  | / "gzip" ; Section 5.1.2.3 |
| / 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. HTTP/1.1 uses |  | All transfer-coding values are case-insensitive. HTTP/1.1 uses |
| transfer-coding values in the TE header field (Section 9.5) and in |  | transfer-coding values in the TE header field (Section 8.4) and in |
| the Transfer-Encoding header field (Section 9.7). |  | the Transfer-Encoding header field (Section 8.6). |
| Transfer-codings are analogous to the Content-Transfer-Encoding |  | Transfer-codings are analogous to the Content-Transfer-Encoding |
| values of MIME, which were designed to enable safe transport of |  | values of MIME, which were designed to enable safe transport of |
| binary data over a 7-bit transport service ([RFC2045], Section 6). |  | binary data over a 7-bit transport service ([RFC2045], Section 6). |
| However, safe transport has a different focus for an 8bit-clean |  | However, safe transport has a different focus for an 8bit-clean |
| transfer protocol. In HTTP, the only unsafe characteristic of |  | transfer protocol. In HTTP, the only unsafe characteristic of |
| message-bodies is the difficulty in determining the exact message |  | message-bodies is the difficulty in determining the exact message |
| body length (Section 3.3), or the desire to encrypt data over a |  | body length (Section 3.3), or the desire to encrypt data over a |
| shared transport. |  | shared transport. |
| 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. A server MUST NOT send transfer-codings |  | then close the connection. A server MUST NOT send transfer-codings |
| to an HTTP/1.0 client. |  | to an HTTP/1.0 client. |
| 6.2.1. Chunked Transfer Coding |  | 5.1.1. 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. |
| Chunked-Body = *chunk |  | Chunked-Body = *chunk |
| last-chunk |  | last-chunk |
| trailer-part |  | trailer-part |
| CRLF |  | CRLF |
| chunk = chunk-size *WSP [ chunk-ext ] CRLF |  | chunk = chunk-size [ chunk-ext ] CRLF |
| chunk-data CRLF |  | chunk-data CRLF |
| chunk-size = 1*HEXDIG |  | chunk-size = 1*HEXDIG |
| last-chunk = 1*("0") *WSP [ chunk-ext ] CRLF |  | last-chunk = 1*("0") [ chunk-ext ] CRLF |
| chunk-ext = *( ";" *WSP chunk-ext-name |  | chunk-ext = *( ";" chunk-ext-name |
| [ "=" chunk-ext-val ] *WSP ) |  | [ "=" 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 = WSP / %x21 / %x23-5B / %x5D-7E / obs-text |  | qdtext-nf = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text |
| ; WSP / <VCHAR except DQUOTE and "\"> / obs-text |  |  |
| 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 |  | The trailer allows the sender to include additional HTTP header |
| fields at the end of the message. The Trailer header field can be |  | 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 |  | used to indicate which header fields are included in a trailer (see |
| Section 9.6). |  | Section 8.5). |
| A server using chunked transfer-coding in a response MUST NOT use the |  | A server using chunked transfer-coding in a response MUST NOT use the |
| trailer for any header fields unless at least one of the following is |  | trailer for any header fields unless at least one of the following is |
| true: |  | true: |
| 1. the request included a TE header field that indicates "trailers" |  | 1. the request included a TE header field that indicates "trailers" |
| is acceptable in the transfer-coding of the response, as |  | is acceptable in the transfer-coding of the response, as |
| described in Section 9.5; or, |  | described in Section 8.4; or, |
| 2. the trailer fields consist entirely of optional metadata, and the |  | 2. the trailer fields consist entirely of optional metadata, and the |
| recipient could use the message (in a manner acceptable to the |  | recipient could use the message (in a manner acceptable to the |
| server where the field originated) without receiving it. In |  | server where the field originated) without receiving it. In |
| other words, the server that generated the header (often but not |  | other words, the server that generated the header (often but not |
| always the origin server) is willing to accept the possibility |  | always the origin server) is willing to accept the possibility |
| that the trailer fields might be silently discarded along the |  | that the trailer fields might be silently discarded along the |
| path to the client. |  | path to the client. |
| This requirement prevents an interoperability failure when the |  | This requirement prevents an interoperability failure when the |
| skipping to change at page 41, line 37 |  | skipping to change at page 38, line 22 |
| messages on a persistent connection. Whenever a transfer-coding is |  | messages on a persistent connection. Whenever a transfer-coding is |
| applied to a payload body in a request, the final transfer-coding |  | applied to a payload body in a request, the final transfer-coding |
| applied MUST be "chunked". If a transfer-coding is applied to a |  | applied MUST be "chunked". If a transfer-coding is applied to a |
| response payload body, then either the final transfer-coding applied |  | response payload body, then either the final transfer-coding applied |
| MUST be "chunked" or the message MUST be terminated by closing the |  | MUST be "chunked" or the message MUST be terminated by closing the |
| connection. When the "chunked" transfer-coding is used, it MUST be |  | connection. When the "chunked" transfer-coding is used, it MUST be |
| the last transfer-coding applied to form the message-body. The |  | the last transfer-coding applied to form the message-body. The |
| "chunked" transfer-coding MUST NOT be applied more than once in a |  | "chunked" transfer-coding MUST NOT be applied more than once in a |
| message-body. |  | message-body. |
| 6.2.2. Compression Codings |  | 5.1.2. 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 |  | Note: Use of program names for the identification of encoding |
| formats is not desirable and is discouraged for future encodings. |  | formats is not desirable and is discouraged for future encodings. |
| Their use here is representative of historical practice, not good |  | Their use here is representative of historical practice, not good |
| design. |  | design. |
| Note: For compatibility with previous implementations of HTTP, |  | Note: For compatibility with previous implementations of HTTP, |
| applications SHOULD consider "x-gzip" and "x-compress" to be |  | applications SHOULD consider "x-gzip" and "x-compress" to be |
| equivalent to "gzip" and "compress" respectively. |  | equivalent to "gzip" and "compress" respectively. |
| 6.2.2.1. Compress Coding |  | 5.1.2.1. 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). |
| 6.2.2.2. Deflate Coding |  | 5.1.2.2. 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. |
| 6.2.2.3. Gzip Coding |  | 5.1.2.3. 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. |
| 6.2.3. Transfer Coding Registry |  | 5.1.3. Transfer Coding Registry |
| The HTTP Transfer Coding Registry defines the name space for the |  | The HTTP Transfer Coding Registry defines the name space for the |
| transfer coding names. |  | transfer coding names. |
| Registrations MUST include the following fields: |  | Registrations MUST include the following fields: |
| o Name |  | o Name |
| o Description |  | o Description |
| o Pointer to specification text |  | o Pointer to specification text |
| Names of transfer codings MUST NOT overlap with names of content |  | Names of transfer codings MUST NOT overlap with names of content |
| codings (Section 2.2 of [Part3]), unless the encoding transformation |  | codings (Section 2.2 of [Part3]), unless the encoding transformation |
| is identical (as it is the case for the compression codings defined |  | is identical (as it is the case for the compression codings defined |
| in Section 6.2.2). |  | in Section 5.1.2). |
| Values to be added to this name space require a specification (see |  | Values to be added to this name space require a specification (see |
| "Specification Required" in Section 4.1 of [RFC5226]), and MUST |  | "Specification Required" in Section 4.1 of [RFC5226]), and MUST |
| conform to the purpose of transfer coding defined in this section. |  | conform to the purpose of transfer coding defined in this section. |
| The registry itself is maintained at |  | The registry itself is maintained at |
| <http://www.iana.org/assignments/http-parameters>. |  | <http://www.iana.org/assignments/http-parameters>. |
| 6.3. Product Tokens |  | 5.2. Product Tokens |
| Product tokens are used to allow communicating applications to |  | Product tokens are used to allow communicating applications to |
| identify themselves by software name and version. Most fields using |  | identify themselves by software name and version. Most fields using |
| product tokens also allow sub-products which form a significant part |  | product tokens also allow sub-products which form a significant part |
| of the application to be listed, separated by whitespace. By |  | of the application to be listed, separated by whitespace. By |
| convention, the products are listed in order of their significance |  | convention, the products are listed in order of their significance |
| for identifying the application. |  | for identifying the application. |
| product = token ["/" product-version] |  | product = token ["/" product-version] |
| product-version = token |  | product-version = token |
| skipping to change at page 43, line 29 |  | skipping to change at page 40, line 12 |
| User-Agent: CERN-LineMode/2.15 libwww/2.17b3 |  | User-Agent: CERN-LineMode/2.15 libwww/2.17b3 |
| Server: Apache/0.8.4 |  | Server: Apache/0.8.4 |
| Product tokens SHOULD be short and to the point. They MUST NOT be |  | Product tokens SHOULD be short and to the point. They MUST NOT be |
| used for advertising or other non-essential information. Although |  | used for advertising or other non-essential information. Although |
| any token octet MAY appear in a product-version, this token SHOULD |  | any token octet MAY appear in a product-version, this token SHOULD |
| only be used for a version identifier (i.e., successive versions of |  | only be used for a version identifier (i.e., successive versions of |
| the same product SHOULD only differ in the product-version portion of |  | the same product SHOULD only differ in the product-version portion of |
| the product value). |  | the product value). |
| 6.4. Quality Values |  | 5.3. Quality Values |
| Both transfer codings (TE request header field, Section 9.5) and |  | Both transfer codings (TE request header field, Section 8.4) and |
| content negotiation (Section 5 of [Part3]) use short "floating point" |  | content negotiation (Section 5 of [Part3]) use short "floating point" |
| numbers to indicate the relative importance ("weight") of various |  | numbers to indicate the relative importance ("weight") of various |
| negotiable parameters. A weight is normalized to a real number in |  | negotiable parameters. A weight is normalized to a real number in |
| the range 0 through 1, where 0 is the minimum and 1 the maximum |  | the range 0 through 1, where 0 is the minimum and 1 the maximum |
| value. If a parameter has a quality value of 0, then content with |  | value. If a parameter has a quality value of 0, then content with |
| this parameter is "not acceptable" for the client. HTTP/1.1 |  | this parameter is "not acceptable" for the client. HTTP/1.1 |
| applications MUST NOT generate more than three digits after the |  | applications MUST NOT generate more than three digits after the |
| decimal point. User configuration of these values SHOULD also be |  | decimal point. User configuration of these values SHOULD also be |
| limited in this fashion. |  | limited in this fashion. |
| qvalue = ( "0" [ "." 0*3DIGIT ] ) |  | qvalue = ( "0" [ "." 0*3DIGIT ] ) |
| / ( "1" [ "." 0*3("0") ] ) |  | / ( "1" [ "." 0*3("0") ] ) |
| Note: "Quality values" is a misnomer, since these values merely |  | Note: "Quality values" is a misnomer, since these values merely |
| represent relative degradation in desired quality. |  | represent relative degradation in desired quality. |
| 7. Connections |  | 6. Connections |
| 7.1. Persistent Connections |  |  |
| 7.1.1. Purpose |  | 6.1. Persistent Connections |
|  |  | 6.1.1. Purpose |
| Prior to persistent connections, a separate TCP connection was |  | Prior to persistent connections, a separate TCP connection was |
| established for each request, increasing the load on HTTP servers and |  | established for each request, increasing the load on HTTP servers and |
| causing congestion on the Internet. The use of inline images and |  | causing congestion on the Internet. The use of inline images and |
| other associated data often requires a client to make multiple |  | other associated data often requires a client to make multiple |
| requests of the same server in a short amount of time. Analysis of |  | requests of the same server in a short amount of time. Analysis of |
| these performance problems and results from a prototype |  | these performance problems and results from a prototype |
| implementation are available [Pad1995] [Spe]. Implementation |  | implementation are available [Pad1995] [Spe]. Implementation |
| experience and measurements of actual HTTP/1.1 implementations show |  | experience and measurements of actual HTTP/1.1 implementations show |
| good results [Nie1997]. Alternatives have also been explored, for |  | good results [Nie1997]. Alternatives have also been explored, for |
| skipping to change at page 44, line 46 |  | skipping to change at page 41, line 26 |
| spent in TCP's connection opening handshake. |  | spent in TCP's connection opening handshake. |
| o HTTP can evolve more gracefully, since errors can be reported |  | o HTTP can evolve more gracefully, since errors can be reported |
| without the penalty of closing the TCP connection. Clients using |  | without the penalty of closing the TCP 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. |
| 7.1.2. Overall Operation |  | 6.1.2. Overall Operation |
| A significant difference between HTTP/1.1 and earlier versions of |  | A significant difference between HTTP/1.1 and earlier versions of |
| HTTP is that persistent connections are the default behavior of any |  | HTTP is that persistent connections are the default behavior of any |
| HTTP connection. That is, unless otherwise indicated, the client |  | HTTP connection. That is, unless otherwise indicated, the client |
| SHOULD assume that the server will maintain a persistent connection, |  | SHOULD assume that the server will maintain a persistent connection, |
| even after error responses from the server. |  | even after error responses from the server. |
| Persistent connections provide a mechanism by which a client and a |  | Persistent connections provide a mechanism by which a client and a |
| server can signal the close of a TCP connection. This signaling |  | server can signal the close of a TCP connection. This signaling |
| takes place using the Connection header field (Section 9.1). Once a |  | takes place using the Connection header field (Section 8.1). Once a |
| close has been signaled, the client MUST NOT send any more requests |  | close has been signaled, the client MUST NOT send any more requests |
| on that connection. |  | on that connection. |
| 7.1.2.1. Negotiation |  | 6.1.2.1. Negotiation |
| An HTTP/1.1 server MAY assume that a HTTP/1.1 client intends to |  | An HTTP/1.1 server MAY assume that a HTTP/1.1 client intends to |
| maintain a persistent connection unless a Connection header field |  | maintain a persistent connection unless a Connection header field |
| including the connection-token "close" was sent in the request. If |  | including the connection-token "close" was sent in the request. If |
| the server chooses to close the connection immediately after sending |  | the server chooses to close the connection immediately after sending |
| the response, it SHOULD send a Connection header field including the |  | the response, it SHOULD send a Connection header field including the |
| connection-token "close". |  | connection-token "close". |
| An HTTP/1.1 client MAY expect a connection to remain open, but would |  | An HTTP/1.1 client MAY expect a connection to remain open, but would |
| decide to keep it open based on whether the response from a server |  | decide to keep it open based on whether the response from a server |
| skipping to change at page 45, line 41 |  | skipping to change at page 42, line 22 |
| 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. |
| In order to remain persistent, all messages on the connection MUST |  | In order to remain persistent, all messages on the connection MUST |
| have a self-defined message length (i.e., one not defined by closure |  | have a self-defined message length (i.e., one not defined by closure |
| of the connection), as described in Section 3.3. |  | of the connection), as described in Section 3.3. |
| 7.1.2.2. Pipelining |  | 6.1.2.2. 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 |
| 7.1.2 of [Part2]). Otherwise, a premature termination of the |  | 6.1.2 of [Part2]). Otherwise, a premature termination of the |
| transport connection could lead to indeterminate results. A client |  | transport connection could lead to indeterminate results. A client |
| wishing to send a non-idempotent request SHOULD wait to send that |  | wishing to send a non-idempotent request SHOULD wait to send that |
| request until it has received the response status line for the |  | request until it has received the response status line for the |
| previous request. |  | previous request. |
| 7.1.3. Proxy Servers |  | 6.1.3. Proxy Servers |
| It is especially important that proxies correctly implement the |  | It is especially important that proxies correctly implement the |
| properties of the Connection header field as specified in |  | properties of the Connection header field as specified in |
| Section 9.1. |  | Section 8.1. |
| The proxy server MUST signal persistent connections separately with |  | The proxy server MUST signal persistent connections separately with |
| its clients and the origin servers (or other proxy servers) that it |  | its clients and the origin servers (or other proxy servers) that it |
| connects to. Each persistent connection applies to only one |  | connects to. Each persistent connection applies to only one |
| transport link. |  | transport link. |
| A proxy server MUST NOT establish a HTTP/1.1 persistent connection |  | 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 |  | 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 |  | information and discussion of the problems with the Keep-Alive header |
| field implemented by many HTTP/1.0 clients). |  | field implemented by many HTTP/1.0 clients). |
| 7.1.3.1. End-to-end and Hop-by-hop Header Fields |  | 6.1.3.1. End-to-end and Hop-by-hop Header Fields |
| For the purpose of defining the behavior of caches and non-caching |  | For the purpose of defining the behavior of caches and non-caching |
| proxies, we divide HTTP header fields into two categories: |  | proxies, we divide HTTP header fields into two categories: |
| o End-to-end header fields, which are transmitted to the ultimate |  | o End-to-end header fields, which are transmitted to the ultimate |
| recipient of a request or response. End-to-end header fields in |  | recipient of a request or response. End-to-end header fields in |
| responses MUST be stored as part of a cache entry and MUST be |  | responses MUST be stored as part of a cache entry and MUST be |
| transmitted in any response formed from a cache entry. |  | transmitted in any response formed from a cache entry. |
| o Hop-by-hop header fields, which are meaningful only for a single |  | o Hop-by-hop header fields, which are meaningful only for a single |
| skipping to change at page 47, line 20 |  | skipping to change at page 43, line 48 |
| o Trailer |  | o Trailer |
| o Transfer-Encoding |  | o Transfer-Encoding |
| o Upgrade |  | o Upgrade |
| All other header fields defined by HTTP/1.1 are end-to-end header |  | All other header fields defined by HTTP/1.1 are end-to-end header |
| fields. |  | fields. |
| Other hop-by-hop header fields MUST be listed in a Connection header |  | Other hop-by-hop header fields MUST be listed in a Connection header |
| field (Section 9.1). |  | field (Section 8.1). |
| 7.1.3.2. Non-modifiable Header Fields |  | 6.1.3.2. Non-modifiable Header Fields |
| Some features of HTTP/1.1, such as Digest Authentication, depend on |  | Some features of HTTP/1.1, such as Digest Authentication, depend on |
| the value of certain end-to-end header fields. A non-transforming |  | the value of certain end-to-end header fields. A non-transforming |
| proxy SHOULD NOT modify an end-to-end header field unless the |  | proxy SHOULD NOT modify an end-to-end header field unless the |
| definition of that header field requires or specifically allows that. |  | definition of that header field requires or specifically allows that. |
| A non-transforming proxy MUST NOT modify any of the following fields |  | A non-transforming proxy MUST NOT modify any of the following fields |
| in a request or response, and it MUST NOT add any of these fields if |  | in a request or response, and it MUST NOT add any of these fields if |
| not already present: |  | not already present: |
| skipping to change at page 48, line 29 |  | skipping to change at page 45, line 13 |
| in the message (see Section 3.6 of [Part6]). |  | in the message (see Section 3.6 of [Part6]). |
| Warning: Unnecessary modification of end-to-end header fields |  | Warning: Unnecessary modification of end-to-end header fields |
| might cause authentication failures if stronger authentication |  | might cause authentication failures if stronger authentication |
| mechanisms are introduced in later versions of HTTP. Such |  | mechanisms are introduced in later versions of HTTP. Such |
| authentication mechanisms MAY rely on the values of header fields |  | authentication mechanisms MAY rely on the values of header fields |
| not listed here. |  | not listed here. |
| A non-transforming proxy MUST preserve the message payload ([Part3]), |  | A non-transforming proxy MUST preserve the message payload ([Part3]), |
| though it MAY change the message-body through application or removal |  | though it MAY change the message-body through application or removal |
| of a transfer-coding (Section 6.2). |  | of a transfer-coding (Section 5.1). |
| 7.1.4. Practical Considerations |  | 6.1.4. Practical Considerations |
| Servers will usually have some time-out value beyond which they will |  | Servers will usually have some time-out value beyond which they will |
| no longer maintain an inactive connection. Proxy servers might make |  | no longer maintain an inactive connection. Proxy servers might make |
| this a higher value since it is likely that the client will be making |  | this a higher value since it is likely that the client will be making |
| more connections through the same server. The use of persistent |  | more connections through the same server. The use of persistent |
| connections places no requirements on the length (or existence) of |  | connections places no requirements on the length (or existence) of |
| this time-out for either the client or the server. |  | this time-out for either the client or the server. |
| When a client or server wishes to time-out it SHOULD issue a graceful |  | When a client or server wishes to time-out it SHOULD issue a graceful |
| close on the transport connection. Clients and servers SHOULD both |  | close on the transport connection. Clients and servers SHOULD both |
| skipping to change at page 49, line 6 |  | skipping to change at page 45, line 38 |
| the other side's close promptly it could cause unnecessary resource |  | the other side's close promptly it could cause unnecessary resource |
| drain on the network. |  | drain on the network. |
| A client, server, or proxy MAY close the transport connection at any |  | 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 |  | 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" |  | 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 |  | 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 |  | closed while it was idle, but from the client's point of view, a |
| request is in progress. |  | request is in progress. |
| This means that clients, servers, and proxies MUST be able to recover |  |  |
| from asynchronous close events. Client software SHOULD reopen the |  |  |
| transport connection and retransmit the aborted sequence of requests |  |  |
| without user interaction so long as the request sequence is |  |  |
| idempotent (see Section 7.1.2 of [Part2]). Non-idempotent request |  |  |
| methods or sequences MUST NOT be automatically retried, although user |  |  |
| agents MAY offer a human operator the choice of retrying the |  |  |
| request(s). Confirmation by user-agent software with semantic |  |  |
| understanding of the application MAY substitute for user |  |  |
| confirmation. The automatic retry SHOULD NOT be repeated if the |  |  |
| second sequence of requests fails. |  |  |
| Servers SHOULD always respond to at least one request per connection, |  |  |
| if at all possible. Servers SHOULD NOT close a connection in the |  |  |
| middle of transmitting a response, unless a network or client failure |  |  |
| is suspected. |  |  |
| Clients (including proxies) SHOULD limit the number of simultaneous |  | Clients (including proxies) SHOULD limit the number of simultaneous |
| connections that they maintain to a given server (including proxies). |  | connections that they maintain to a given server (including proxies). |
| Previous revisions of HTTP gave a specific number of connections as a |  | Previous revisions of HTTP gave a specific number of connections as a |
| ceiling, but this was found to be impractical for many applications. |  | ceiling, but this was found to be impractical for many applications. |
| As a result, this specification does not mandate a particular maximum |  | As a result, this specification does not mandate a particular maximum |
| number of connections, but instead encourages clients to be |  | number of connections, but instead encourages clients to be |
| conservative when opening multiple connections. |  | conservative when opening multiple connections. |
| In particular, while using multiple connections avoids the "head-of- |  | In particular, while using multiple connections avoids the "head-of- |
| line blocking" problem (whereby a request that takes significant |  | line blocking" problem (whereby a request that takes significant |
| server-side processing and/or has a large payload can block |  | server-side processing and/or has a large payload can block |
| subsequent requests on the same connection), each connection used |  | subsequent requests on the same connection), each connection used |
| consumes server resources (sometimes significantly), and furthermore |  | consumes server resources (sometimes significantly), and furthermore |
| using multiple connections can cause undesirable side effects in |  | using multiple connections can cause undesirable side effects in |
| congested networks. |  | congested networks. |
| Note that servers might reject traffic that they deem abusive, |  | Note that servers might reject traffic that they deem abusive, |
| including an excessive number of connections from a client. |  | including an excessive number of connections from a client. |
| 7.2. Message Transmission Requirements |  | 6.1.5. Retrying Requests |
| 7.2.1. Persistent Connections and Flow Control |  | Senders can close the transport connection at any time. Therefore, |
|  |  | clients, servers, and proxies MUST be able to recover from |
|  |  | asynchronous close events. Client software MAY reopen the transport |
|  |  | connection and retransmit the aborted sequence of requests without |
|  |  | user interaction so long as the request sequence is idempotent (see |
|  |  | Section 6.1.2 of [Part2]). Non-idempotent request methods or |
|  |  | sequences MUST NOT be automatically retried, although user agents MAY |
|  |  | offer a human operator the choice of retrying the request(s). |
|  |  | Confirmation by user-agent software with semantic understanding of |
|  |  | the application MAY substitute for user confirmation. The automatic |
|  |  | retry SHOULD NOT be repeated if the second sequence of requests |
|  |  | fails. |
|  |  | 6.2. Message Transmission Requirements |
|  |  | 6.2.1. Persistent Connections and Flow Control |
| HTTP/1.1 servers SHOULD maintain persistent connections and use TCP's |  | HTTP/1.1 servers SHOULD maintain persistent connections and use TCP's |
| flow control mechanisms to resolve temporary overloads, rather than |  | flow control mechanisms to resolve temporary overloads, rather than |
| terminating connections with the expectation that clients will retry. |  | terminating connections with the expectation that clients will retry. |
| The latter technique can exacerbate network congestion. |  | The latter technique can exacerbate network congestion. |
| 7.2.2. Monitoring Connections for Error Status Messages |  | 6.2.2. Monitoring Connections for Error Status Messages |
| An HTTP/1.1 (or later) client sending a message-body SHOULD monitor |  | An HTTP/1.1 (or later) client sending a message-body SHOULD monitor |
| the network connection for an error status code while it is |  | the network connection for an error status code while it is |
| transmitting the request. If the client sees an error status code, |  | transmitting the request. If the client sees an error status code, |
| it SHOULD immediately cease transmitting the body. If the body is |  | it SHOULD immediately cease transmitting the body. If the body is |
| being sent using a "chunked" encoding (Section 6.2), a zero length |  | being sent using a "chunked" encoding (Section 5.1), a zero length |
| chunk and empty trailer MAY be used to prematurely mark the end of |  | chunk and empty trailer MAY be used to prematurely mark the end of |
| the message. If the body was preceded by a Content-Length header |  | the message. If the body was preceded by a Content-Length header |
| field, the client MUST close the connection. |  | field, the client MUST close the connection. |
| 7.2.3. Use of the 100 (Continue) Status |  | 6.2.3. Use of the 100 (Continue) Status |
| The purpose of the 100 (Continue) status code (see Section 8.1.1 of |  | The purpose of the 100 (Continue) status code (see Section 7.1.1 of |
| [Part2]) is to allow a client that is sending a request message with |  | [Part2]) is to allow a client that is sending a request message with |
| a request body to determine if the origin server is willing to accept |  | a request body to determine if the origin server is willing to accept |
| the request (based on the request header fields) before the client |  | the request (based on the request header fields) before the client |
| sends the request body. In some cases, it might either be |  | sends the request body. In some cases, it might either be |
| inappropriate or highly inefficient for the client to send the body |  | inappropriate or highly inefficient for the client to send the body |
| if the server will reject the message without looking at the body. |  | if the server will reject the message without looking at the body. |
| Requirements for HTTP/1.1 clients: |  | Requirements for HTTP/1.1 clients: |
| o If a client will wait for a 100 (Continue) response before sending |  | o If a client will wait for a 100 (Continue) response before sending |
| the request body, it MUST send an Expect header field (Section 9.2 |  | the request body, it MUST send an Expect header field (Section 9.3 |
| of [Part2]) with the "100-continue" expectation. |  | of [Part2]) with the "100-continue" expectation. |
| o A client MUST NOT send an Expect header field (Section 9.2 of |  | o A client MUST NOT send an Expect header field (Section 9.3 of |
| [Part2]) with the "100-continue" expectation if it does not intend |  | [Part2]) with the "100-continue" expectation if it does not intend |
| to send a request body. |  | to send a request body. |
| Because of the presence of older implementations, the protocol allows |  | Because of the presence of older implementations, the protocol allows |
| ambiguous situations in which a client might send "Expect: 100- |  | ambiguous situations in which a client might send "Expect: 100- |
| continue" without receiving either a 417 (Expectation Failed) or a |  | continue" without receiving either a 417 (Expectation Failed) or a |
| 100 (Continue) status code. Therefore, when a client sends this |  | 100 (Continue) status code. Therefore, when a client sends this |
| header field to an origin server (possibly via a proxy) from which it |  | header field to an origin server (possibly via a proxy) from which it |
| has never seen a 100 (Continue) status code, the client SHOULD NOT |  | has never seen a 100 (Continue) status code, the client SHOULD NOT |
| wait for an indefinite period before sending the request body. |  | wait for an indefinite period before sending the request body. |
| skipping to change at page 52, line 12 |  | skipping to change at page 48, line 41 |
| HTTP/1.0 or lower, it MUST NOT forward the request, and it MUST |  | HTTP/1.0 or lower, it MUST NOT forward the request, and it MUST |
| respond with a 417 (Expectation Failed) status code. |  | respond with a 417 (Expectation Failed) status code. |
| o Proxies SHOULD maintain a record of the HTTP version numbers |  | o Proxies SHOULD maintain a record of the HTTP version numbers |
| received from recently-referenced next-hop servers. |  | received from recently-referenced next-hop servers. |
| o A proxy MUST NOT forward a 100 (Continue) response if the request |  | o A proxy MUST NOT forward a 100 (Continue) response if the request |
| message was received from an HTTP/1.0 (or earlier) client and did |  | message was received from an HTTP/1.0 (or earlier) client and did |
| not include an Expect header field with the "100-continue" |  | not include an Expect header field with the "100-continue" |
| expectation. This requirement overrides the general rule for |  | expectation. This requirement overrides the general rule for |
| forwarding of 1xx responses (see Section 8.1 of [Part2]). |  | forwarding of 1xx responses (see Section 7.1 of [Part2]). |
| 7.2.4. Client Behavior if Server Prematurely Closes Connection |  |  |
| If an HTTP/1.1 client sends a request which includes a request body, |  |  |
| but which does not include an Expect header field with the "100- |  |  |
| continue" expectation, and if the client is not directly connected to |  |  |
| an HTTP/1.1 origin server, and if the client sees the connection |  |  |
| close before receiving a status line from the server, the client |  |  |
| SHOULD retry the request. If the client does retry this request, it |  |  |
| MAY use the following "binary exponential backoff" algorithm to be |  |  |
| assured of obtaining a reliable response: |  |  |
| 1. Initiate a new connection to the server |  |  |
| 2. Transmit the request-line, header fields, and the CRLF that |  |  |
| indicates the end of header fields. |  |  |
| 3. Initialize a variable R to the estimated round-trip time to the |  |  |
| server (e.g., based on the time it took to establish the |  |  |
| connection), or to a constant value of 5 seconds if the round- |  |  |
| trip time is not available. |  |  |
| 4. Compute T = R * (2**N), where N is the number of previous retries |  |  |
| of this request. |  |  |
| 5. Wait either for an error response from the server, or for T |  |  |
| seconds (whichever comes first) |  |  |
| 6. If no error response is received, after T seconds transmit the |  |  |
| body of the request. |  |  |
| 7. If client sees that the connection is closed prematurely, repeat |  |  |
| from step 1 until the request is accepted, an error response is |  |  |
| received, or the user becomes impatient and terminates the retry |  |  |
| process. |  |  |
| If at any point an error status code is received, the client |  |  |
| o SHOULD NOT continue and |  |  |
| o SHOULD close the connection if it has not completed sending the |  |  |
| request message. |  |  |
| 8. Miscellaneous notes that might disappear |  | 7. Miscellaneous notes that might disappear |
| 8.1. Scheme aliases considered harmful |  | 7.1. Scheme aliases considered harmful |
| [[TBD-aliases-harmful: describe why aliases like webcal are |  | [[TBD-aliases-harmful: describe why aliases like webcal are |
| harmful.]] |  | harmful.]] |
| 8.2. Use of HTTP for proxy communication |  | 7.2. Use of HTTP for proxy communication |
| [[TBD-proxy-other: Configured to use HTTP to proxy HTTP or other |  | [[TBD-proxy-other: Configured to use HTTP to proxy HTTP or other |
| protocols.]] |  | protocols.]] |
| 8.3. Interception of HTTP for access control |  | 7.3. Interception of HTTP for access control |
| [[TBD-intercept: Interception of HTTP traffic for initiating access |  | [[TBD-intercept: Interception of HTTP traffic for initiating access |
| control.]] |  | control.]] |
| 8.4. Use of HTTP by other protocols |  | 7.4. Use of HTTP by other protocols |
| [[TBD-profiles: Profiles of HTTP defined by other protocol. |  | [[TBD-profiles: Profiles of HTTP defined by other protocol. |
| Extensions of HTTP like WebDAV.]] |  | Extensions of HTTP like WebDAV.]] |
| 8.5. Use of HTTP by media type specification |  | 7.5. Use of HTTP by media type specification |
| [[TBD-hypertext: Instructions on composing HTTP requests via |  | [[TBD-hypertext: Instructions on composing HTTP requests via |
| hypertext formats.]] |  | hypertext formats.]] |
| 9. Header Field Definitions |  | 8. Header Field Definitions |
| This section defines the syntax and semantics of HTTP header fields |  | This section defines the syntax and semantics of HTTP header fields |
| related to message framing and transport protocols. |  | related to message origination, framing, and routing. |
| 9.1. Connection |  | +-------------------+---------------+ |
|  |  | | Header Field Name | Defined in... | |
|  |  | +-------------------+---------------+ |
|  |  | | Connection | Section 8.1 | |
|  |  | | Content-Length | Section 8.2 | |
|  |  | | Host | Section 8.3 | |
|  |  | | TE | Section 8.4 | |
|  |  | | Trailer | Section 8.5 | |
|  |  | | Transfer-Encoding | Section 8.6 | |
|  |  | | Upgrade | Section 8.7 | |
|  |  | | Via | Section 8.8 | |
|  |  | +-------------------+---------------+ |
|  |  | 8.1. Connection |
| The "Connection" header field allows the sender to specify options |  | The "Connection" header field allows the sender to specify options |
| that are desired only for that particular connection. Such |  | that are desired only for that particular connection. Such |
| connection options MUST be removed or replaced before the message can |  | connection options MUST be removed or replaced before the message can |
| be forwarded downstream by a proxy or gateway. This mechanism also |  | be forwarded downstream by a proxy or gateway. This mechanism also |
| allows the sender to indicate which HTTP header fields used in the |  | allows the sender to indicate which HTTP header fields used in the |
| message are only intended for the immediate recipient ("hop-by-hop"), |  | message are only intended for the immediate recipient ("hop-by-hop"), |
| as opposed to all recipients on the chain ("end-to-end"), enabling |  | as opposed to all recipients on the chain ("end-to-end"), enabling |
| the message to be self-descriptive and allowing future connection- |  | the message to be self-descriptive and allowing future connection- |
| specific extensions to be deployed in HTTP without fear that they |  | specific extensions to be deployed in HTTP without fear that they |
| skipping to change at page 54, line 50 |  | skipping to change at page 51, line 4 |
| since it would be unwise for senders to use that field-name for |  | since it would be unwise for senders to use that field-name for |
| anything else. |  | anything else. |
| HTTP/1.1 defines the "close" connection option for the sender to |  | HTTP/1.1 defines the "close" connection option for the sender to |
| signal that the connection will be closed after completion of the |  | signal that the connection will be closed after completion of the |
| response. For example, |  | response. For example, |
| Connection: close |  | Connection: close |
| in either the request or the response header fields indicates that |  | in either the request or the response header fields indicates that |
| the connection SHOULD NOT be considered "persistent" (Section 7.1) |  | the connection SHOULD NOT be considered "persistent" (Section 6.1) |
| after the current request/response is complete. |  | after the current request/response is complete. |
| An HTTP/1.1 client that does not support persistent connections MUST |  | An HTTP/1.1 client that does not support persistent connections MUST |
| include the "close" connection option in every request message. |  | include the "close" connection option in every request message. |
| An HTTP/1.1 server that does not support persistent connections MUST |  | An HTTP/1.1 server that does not support persistent connections MUST |
| include the "close" connection option in every response message that |  | include the "close" connection option in every response message that |
| does not have a 1xx (Informational) status code. |  | does not have a 1xx (Informational) status code. |
| 9.2. Content-Length |  | 8.2. Content-Length |
| The "Content-Length" header field indicates the size of the message- |  | The "Content-Length" header field indicates the size of the message- |
| body, in decimal number of octets, for any message other than a |  | body, in decimal number of octets, for any message other than a |
| response to a HEAD request or a response with a status code of 304. |  | response to a HEAD request or a response with a status code of 304. |
| In the case of a response to a HEAD request, Content-Length indicates |  | In the case of a response to a HEAD request, Content-Length indicates |
| the size of the payload body (not including any potential transfer- |  | the size of the payload body (not including any potential transfer- |
| coding) that would have been sent had the request been a GET. In the |  | coding) that would have been sent had the request been a GET. In the |
| case of a 304 (Not Modified) response to a GET request, Content- |  | case of a 304 (Not Modified) response to a GET request, Content- |
| Length indicates the size of the payload body (not including any |  | Length indicates the size of the payload body (not including any |
| potential transfer-coding) that would have been sent in a 200 (OK) |  | potential transfer-coding) that would have been sent in a 200 (OK) |
| skipping to change at page 55, line 43 |  | skipping to change at page 51, line 45 |
| body length can be determined prior to being transferred. |  | body length can be determined prior to being transferred. |
| Section 3.3 describes how recipients determine the length of a |  | Section 3.3 describes how recipients determine the length of a |
| message-body. |  | message-body. |
| Any Content-Length greater than or equal to zero is a valid value. |  | Any Content-Length greater than or equal to zero is a valid value. |
| Note that the use of this field in HTTP is significantly different |  | Note that the use of this field in HTTP is significantly different |
| from the corresponding definition in MIME, where it is an optional |  | from the corresponding definition in MIME, where it is an optional |
| field used within the "message/external-body" content-type. |  | field used within the "message/external-body" content-type. |
| 9.3. Date |  | 8.3. Host |
| The "Date" header field represents the date and time at which the |  |  |
| message was originated, having the same semantics as the Origination |  |  |
| Date Field (orig-date) defined in Section 3.6.1 of [RFC5322]. The |  |  |
| field value is an HTTP-date, as described in Section 6.1; it MUST be |  |  |
| sent in rfc1123-date format. |  |  |
| Date = HTTP-date |  |  |
| An example is |  |  |
| Date: Tue, 15 Nov 1994 08:12:31 GMT |  |  |
| Origin servers MUST include a Date header field in all responses, |  |  |
| except in these cases: |  |  |
| 1. If the response status code is 100 (Continue) or 101 (Switching |  |  |
| Protocols), the response MAY include a Date header field, at the |  |  |
| server's option. |  |  |
| 2. If the response status code conveys a server error, e.g., 500 |  |  |
| (Internal Server Error) or 503 (Service Unavailable), and it is |  |  |
| inconvenient or impossible to generate a valid Date. |  |  |
| 3. If the server does not have a clock that can provide a reasonable |  |  |
| approximation of the current time, its responses MUST NOT include |  |  |
| a Date header field. In this case, the rules in Section 9.3.1 |  |  |
| MUST be followed. |  |  |
| A received message that does not have a Date header field MUST be |  |  |
| assigned one by the recipient if the message will be cached by that |  |  |
| recipient. |  |  |
| Clients can use the Date header field as well; in order to keep |  |  |
| request messages small, they are advised not to include it when it |  |  |
| doesn't convey any useful information (as it is usually the case for |  |  |
| requests that do not contain a payload). |  |  |
| The HTTP-date sent in a Date header field SHOULD NOT represent a date |  |  |
| and time subsequent to the generation of the message. It SHOULD |  |  |
| represent the best available approximation of the date and time of |  |  |
| message generation, unless the implementation has no means of |  |  |
| generating a reasonably accurate date and time. In theory, the date |  |  |
| ought to represent the moment just before the payload is generated. |  |  |
| In practice, the date can be generated at any time during the message |  |  |
| origination without affecting its semantic value. |  |  |
| 9.3.1. Clockless Origin Server Operation |  |  |
| Some origin server implementations might not have a clock available. |  |  |
| An origin server without a clock MUST NOT assign Expires or Last- |  |  |
| Modified values to a response, unless these values were associated |  |  |
| with the resource by a system or user with a reliable clock. It MAY |  |  |
| assign an Expires value that is known, at or before server |  |  |
| configuration time, to be in the past (this allows "pre-expiration" |  |  |
| of responses without storing separate Expires values for each |  |  |
| resource). |  |  |
| 9.4. 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 resource's URI, enabling the origin |  | information from the target resource's URI, enabling the origin |
| server to distinguish between resources while servicing requests for |  | server to distinguish between resources while servicing requests for |
| multiple host names on a single IP address. Since the Host field- |  | multiple host names on a single IP address. Since the Host field- |
| value is critical information for handling a request, it SHOULD be |  | value is critical information for handling a request, it SHOULD be |
| sent as the first header field following the Request-Line. |  | sent as the first header field following the Request-Line. |
| Host = uri-host [ ":" port ] ; Section 2.7.1 |  | Host = uri-host [ ":" port ] ; Section 2.7.1 |
| skipping to change at page 58, line 9 |  | skipping to change at page 53, line 5 |
| that the intercepted connection is targeting a valid IP address for |  | that the intercepted connection is targeting a valid IP address for |
| that host. |  | that host. |
| A server MUST respond with a 400 (Bad Request) status code to any |  | A server MUST respond with a 400 (Bad Request) status code to any |
| HTTP/1.1 request message that lacks a Host header field and to any |  | HTTP/1.1 request message that lacks a Host header field and to any |
| request message that contains more than one Host header field or a |  | request message that contains more than one Host header field or a |
| Host header field with an invalid field-value. |  | Host header field with an invalid field-value. |
| See Sections 4.2 and A.1.1 for other requirements relating to Host. |  | See Sections 4.2 and A.1.1 for other requirements relating to Host. |
| 9.5. TE |  | 8.4. TE |
| The "TE" header field indicates what extension transfer-codings it is |  | The "TE" header field indicates what extension transfer-codings it is |
| willing to accept in the response, and whether or not it is willing |  | willing to accept in the response, and whether or not it is willing |
| to accept trailer fields in a chunked transfer-coding. |  | to accept trailer fields in a chunked transfer-coding. |
| Its value consists of the keyword "trailers" and/or a comma-separated |  | Its value consists of the keyword "trailers" and/or a comma-separated |
| list of extension transfer-coding names with optional accept |  | list of extension transfer-coding names with optional accept |
| parameters (as described in Section 6.2). |  | parameters (as described in Section 5.1). |
| TE = #t-codings |  | TE = #t-codings |
| t-codings = "trailers" / ( transfer-extension [ te-params ] ) |  | t-codings = "trailers" / ( transfer-extension [ te-params ] ) |
| te-params = OWS ";" OWS "q=" qvalue *( te-ext ) |  | te-params = OWS ";" OWS "q=" qvalue *( te-ext ) |
| te-ext = OWS ";" OWS token [ "=" word ] |  | te-ext = OWS ";" OWS token [ "=" word ] |
| The presence of the keyword "trailers" indicates that the client is |  | The presence of the keyword "trailers" indicates that the client is |
| willing to accept trailer fields in a chunked transfer-coding, as |  | willing to accept trailer fields in a chunked transfer-coding, as |
| defined in Section 6.2.1. This keyword is reserved for use with |  | defined in Section 5.1.1. This keyword is reserved for use with |
| transfer-coding values even though it does not itself represent a |  | transfer-coding values even though it does not itself represent a |
| transfer-coding. |  | transfer-coding. |
| Examples of its use are: |  | Examples of its use are: |
| 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 TE header field only applies to the immediate connection. |
| Therefore, the keyword MUST be supplied within a Connection header |  | Therefore, the keyword MUST be supplied within a Connection header |
| field (Section 9.1) whenever TE is present in an HTTP/1.1 message. |  | field (Section 8.1) whenever TE is present in an HTTP/1.1 message. |
| A server tests whether a transfer-coding is acceptable, according to |  | A server tests whether a transfer-coding is acceptable, according to |
| a TE field, using these rules: |  | a TE field, using these rules: |
| 1. The "chunked" transfer-coding is always acceptable. If the |  | 1. The "chunked" transfer-coding is always acceptable. If the |
| keyword "trailers" is listed, the client indicates that it is |  | keyword "trailers" is listed, the client indicates that it is |
| willing to accept trailer fields in the chunked response on |  | willing to accept trailer fields in the chunked response on |
| behalf of itself and any downstream clients. The implication is |  | behalf of itself and any downstream clients. The implication is |
| that, if given, the client is stating that either all downstream |  | that, if given, the client is stating that either all downstream |
| clients are willing to accept trailer fields in the forwarded |  | clients are willing to accept trailer fields in the forwarded |
| response, or that it will attempt to buffer the response on |  | response, or that it will attempt to buffer the response on |
| behalf of downstream recipients. |  | behalf of downstream recipients. |
| Note: HTTP/1.1 does not define any means to limit the size of a |  | 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 |  | chunked response such that a client can be assured of buffering |
| the entire response. |  | the entire response. |
| 2. If the transfer-coding being tested is one of the transfer- |  | 2. If the transfer-coding being tested is one of the transfer- |
| codings listed in the TE field, then it is acceptable unless it |  | codings listed in the TE field, then it is acceptable unless it |
| is accompanied by a qvalue of 0. (As defined in Section 6.4, a |  | is accompanied by a qvalue of 0. (As defined in Section 5.3, a |
| qvalue of 0 means "not acceptable".) |  | qvalue of 0 means "not acceptable".) |
| 3. If multiple transfer-codings are acceptable, then the acceptable |  | 3. If multiple transfer-codings are acceptable, then the acceptable |
| transfer-coding with the highest non-zero qvalue is preferred. |  | transfer-coding with the highest non-zero qvalue is preferred. |
| The "chunked" transfer-coding always has a qvalue of 1. |  | The "chunked" transfer-coding always has a qvalue of 1. |
| If the TE field-value is empty or if no TE field is present, the only |  | If the TE field-value is empty or if no TE field is present, the only |
| transfer-coding is "chunked". A message with no transfer-coding is |  | transfer-coding is "chunked". A message with no transfer-coding is |
| always acceptable. |  | always acceptable. |
| 9.6. Trailer |  | 8.5. Trailer |
| The "Trailer" header field indicates that the given set of header |  | The "Trailer" header field indicates that the given set of header |
| fields is present in the trailer of a message encoded with chunked |  | fields is present in the trailer of a message encoded with chunked |
| transfer-coding. |  | transfer-coding. |
| Trailer = 1#field-name |  | Trailer = 1#field-name |
| An HTTP/1.1 message SHOULD include a Trailer header field in a |  | An HTTP/1.1 message SHOULD include a Trailer header field in a |
| message using chunked transfer-coding with a non-empty trailer. |  | message using chunked transfer-coding with a non-empty trailer. |
| Doing so allows the recipient to know which header fields to expect |  | Doing so allows the recipient to know which header fields to expect |
| in the trailer. |  | in the trailer. |
| If no Trailer header field is present, the trailer SHOULD NOT include |  | If no Trailer header field is present, the trailer SHOULD NOT include |
| any header fields. See Section 6.2.1 for restrictions on the use of |  | any header fields. See Section 5.1.1 for restrictions on the use of |
| trailer fields in a "chunked" transfer-coding. |  | trailer fields in a "chunked" transfer-coding. |
| Message header fields listed in the Trailer header field MUST NOT |  | Message header fields listed in the Trailer header field MUST NOT |
| include the following header fields: |  | include the following header fields: |
| o Transfer-Encoding |  | o Transfer-Encoding |
| o Content-Length |  | o Content-Length |
| o Trailer |  | o Trailer |
| 9.7. Transfer-Encoding |  | 8.6. Transfer-Encoding |
| The "Transfer-Encoding" header field indicates what transfer-codings |  | The "Transfer-Encoding" header field indicates what transfer-codings |
| (if any) have been applied to the message body. It differs from |  | (if any) have been applied to the message body. It differs from |
| Content-Encoding (Section 2.2 of [Part3]) in that transfer-codings |  | Content-Encoding (Section 2.2 of [Part3]) in that transfer-codings |
| are a property of the message (and therefore are removed by |  | are a property of the message (and therefore are removed by |
| intermediaries), whereas content-codings are not. |  | intermediaries), whereas content-codings are not. |
| Transfer-Encoding = 1#transfer-coding |  | Transfer-Encoding = 1#transfer-coding |
| Transfer-codings are defined in Section 6.2. An example is: |  | Transfer-codings are defined in Section 5.1. An example is: |
| Transfer-Encoding: chunked |  | Transfer-Encoding: chunked |
| If multiple encodings have been applied to a representation, the |  | If multiple encodings have been applied to a representation, the |
| transfer-codings MUST be listed in the order in which they were |  | transfer-codings MUST be listed in the order in which they were |
| applied. Additional information about the encoding parameters MAY be |  | applied. Additional information about the encoding parameters MAY be |
| provided by other header fields not defined by this specification. |  | provided by other header fields not defined by this specification. |
| Many older HTTP/1.0 applications do not understand the Transfer- |  | Many older HTTP/1.0 applications do not understand the Transfer- |
| Encoding header field. |  | Encoding header field. |
| 9.8. Upgrade |  | 8.7. Upgrade |
| The "Upgrade" header field allows the client to specify what |  | The "Upgrade" header field allows the client to specify what |
| additional communication protocols it would like to use, if the |  | additional communication protocols it would like to use, if the |
| server chooses to switch protocols. Servers can use it to indicate |  | server chooses to switch protocols. Servers can use it to indicate |
| what protocols they are willing to switch to. |  | what protocols they are willing to switch to. |
| Upgrade = 1#product |  | Upgrade = 1#product |
| For example, |  | For example, |
| skipping to change at page 61, line 9 |  | skipping to change at page 56, line 4 |
| protocols upon the existing transport-layer connection. Upgrade |  | protocols upon the existing transport-layer connection. Upgrade |
| cannot be used to insist on a protocol change; its acceptance and use |  | cannot be used to insist on a protocol change; its acceptance and use |
| by the server is optional. The capabilities and nature of the |  | by the server is optional. The capabilities and nature of the |
| application-layer communication after the protocol change is entirely |  | application-layer communication after the protocol change is entirely |
| dependent upon the new protocol chosen, although the first action |  | dependent upon the new protocol chosen, although the first action |
| after changing the protocol MUST be a response to the initial HTTP |  | after changing the protocol MUST be a response to the initial HTTP |
| request containing the Upgrade header field. |  | request containing the Upgrade header field. |
| The Upgrade header field only applies to the immediate connection. |  | The Upgrade header field only applies to the immediate connection. |
| Therefore, the upgrade keyword MUST be supplied within a Connection |  | Therefore, the upgrade keyword MUST be supplied within a Connection |
| header field (Section 9.1) whenever Upgrade is present in an HTTP/1.1 |  | header field (Section 8.1) whenever Upgrade is present in an HTTP/1.1 |
| message. |  | message. |
| The Upgrade header field cannot be used to indicate a switch to a |  | The Upgrade header field cannot be used to indicate a switch to a |
| protocol on a different connection. For that purpose, it is more |  | protocol on a different connection. For that purpose, it is more |
| appropriate to use a 3xx redirection response (Section 8.3 of |  | appropriate to use a 3xx redirection response (Section 7.3 of |
| [Part2]). |  | [Part2]). |
| Servers MUST include the "Upgrade" header field in 101 (Switching |  | Servers MUST include the "Upgrade" header field in 101 (Switching |
| Protocols) responses to indicate which protocol(s) are being switched |  | Protocols) responses to indicate which protocol(s) are being switched |
| to, and MUST include it in 426 (Upgrade Required) responses to |  | to, and MUST include it in 426 (Upgrade Required) responses to |
| indicate acceptable protocols to upgrade to. Servers MAY include it |  | indicate acceptable protocols to upgrade to. Servers MAY include it |
| in any other response to indicate that they are willing to upgrade to |  | in any other response to indicate that they are willing to upgrade to |
| one of the specified protocols. |  | one of the specified protocols. |
| This specification only defines the protocol name "HTTP" for use by |  | This specification only defines the protocol name "HTTP" for use by |
| the family of Hypertext Transfer Protocols, as defined by the HTTP |  | the family of Hypertext Transfer Protocols, as defined by the HTTP |
| version rules of Section 2.6 and future updates to this |  | version rules of Section 2.6 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 below. |  | the registration procedure defined below. |
| 9.8.1. Upgrade Token Registry |  | 8.7.1. Upgrade Token Registry |
| The HTTP Upgrade Token Registry defines the name space for product |  | The HTTP Upgrade Token Registry defines the name space for product |
| tokens used to identify protocols in the Upgrade header field. Each |  | tokens used to identify protocols in the Upgrade header field. Each |
| registered token is associated with contact information and an |  | registered token is associated with contact information and an |
| optional set of specifications that details how the connection will |  | optional set of specifications that details how the connection will |
| be processed after it has been upgraded. |  | be processed after it has been upgraded. |
| Registrations are allowed on a First Come First Served basis as |  | Registrations are allowed on a First Come First Served basis as |
| described in Section 4.1 of [RFC5226]. The specifications need not |  | described in Section 4.1 of [RFC5226]. The specifications need not |
| be IETF documents or be subject to IESG review. Registrations are |  | be IETF documents or be subject to IESG review. Registrations are |
| skipping to change at page 62, line 17 |  | skipping to change at page 57, line 13 |
| available upon request. |  | available upon request. |
| 6. The responsible party for the first registration of a "product" |  | 6. The responsible party for the first registration of a "product" |
| token MUST approve later registrations of a "version" token |  | token MUST approve later registrations of a "version" token |
| together with that "product" token before they can be registered. |  | together with that "product" token before they can be registered. |
| 7. If absolutely required, the IESG MAY reassign the responsibility |  | 7. If absolutely required, the IESG MAY reassign the responsibility |
| for a token. This will normally only be used in the case when a |  | for a token. This will normally only be used in the case when a |
| responsible party cannot be contacted. |  | responsible party cannot be contacted. |
| 9.9. Via |  | 8.8. Via |
| The "Via" header field MUST be sent by a proxy or gateway to indicate |  | 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 intermediate protocols and recipients between the user agent and |
| the server on requests, and between the origin server and the client |  | the server on requests, and between the origin server and the client |
| on responses. It is analogous to the "Received" field used by email |  | 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 |  | systems (Section 3.6.7 of [RFC5322]) and is intended to be used for |
| tracking message forwards, avoiding request loops, and identifying |  | tracking message forwards, avoiding request loops, and identifying |
| the protocol capabilities of all senders along the request/response |  | the protocol capabilities of all senders along the request/response |
| chain. |  | chain. |
| skipping to change at page 63, line 42 |  | skipping to change at page 58, line 38 |
| could be collapsed to |  | could be collapsed to |
| Via: 1.0 ricky, 1.1 mertz, 1.0 lucy |  | Via: 1.0 ricky, 1.1 mertz, 1.0 lucy |
| Senders SHOULD NOT combine multiple entries unless they are all under |  | Senders SHOULD NOT combine multiple entries unless they are all under |
| the same organizational control and the hosts have already been |  | the same organizational control and the hosts have already been |
| replaced by pseudonyms. Senders MUST NOT combine entries which have |  | replaced by pseudonyms. Senders MUST NOT combine entries which have |
| different received-protocol values. |  | different received-protocol values. |
| 10. IANA Considerations |  | 9. IANA Considerations |
| 10.1. Header Field Registration |  | 9.1. Header Field Registration |
| The Message Header Field Registry located at <http://www.iana.org/ |  | The Message Header Field Registry located at <http://www.iana.org/ |
| assignments/message-headers/message-header-index.html> shall be |  | assignments/message-headers/message-header-index.html> shall be |
| updated with the permanent registrations below (see [RFC3864]): |  | updated with the permanent registrations below (see [RFC3864]): |
| +-------------------+----------+----------+-------------+ |  | +-------------------+----------+----------+-------------+ |
| | Header Field Name | Protocol | Status | Reference | |  | | Header Field Name | Protocol | Status | Reference | |
| +-------------------+----------+----------+-------------+ |  | +-------------------+----------+----------+-------------+ |
| | Connection | http | standard | Section 9.1 | |  | | Connection | http | standard | Section 8.1 | |
| | Content-Length | http | standard | Section 9.2 | |  | | Content-Length | http | standard | Section 8.2 | |
| | Date | http | standard | Section 9.3 | |  | | Host | http | standard | Section 8.3 | |
| | Host | http | standard | Section 9.4 | |  | | TE | http | standard | Section 8.4 | |
| | TE | http | standard | Section 9.5 | |  | | Trailer | http | standard | Section 8.5 | |
| | Trailer | http | standard | Section 9.6 | |  | | Transfer-Encoding | http | standard | Section 8.6 | |
| | Transfer-Encoding | http | standard | Section 9.7 | |  | | Upgrade | http | standard | Section 8.7 | |
| | Upgrade | http | standard | Section 9.8 | |  | | Via | http | standard | Section 8.8 | |
| | Via | http | standard | Section 9.9 | |  |  |
| +-------------------+----------+----------+-------------+ |  | +-------------------+----------+----------+-------------+ |
| Furthermore, the header field name "Close" shall be registered as |  | Furthermore, the header field name "Close" shall be registered as |
| "reserved", as its use as HTTP header field would be in conflict with |  | "reserved", as its use as HTTP header field would be in conflict with |
| the use of the "close" connection option for the "Connection" header |  | the use of the "close" connection option for the "Connection" header |
| field (Section 9.1). |  | field (Section 8.1). |
| +-------------------+----------+----------+--------------+ |  | +-------------------+----------+----------+-------------+ |
| | Header Field Name | Protocol | Status | Reference | |  | | Header Field Name | Protocol | Status | Reference | |
| +-------------------+----------+----------+--------------+ |  | +-------------------+----------+----------+-------------+ |
| | Close | http | reserved | Section 10.1 | |  | | Close | http | reserved | Section 9.1 | |
| +-------------------+----------+----------+--------------+ |  | +-------------------+----------+----------+-------------+ |
| The change controller is: "IETF (iesg@ietf.org) - Internet |  | The change controller is: "IETF (iesg@ietf.org) - Internet |
| Engineering Task Force". |  | Engineering Task Force". |
| 10.2. URI Scheme Registration |  | 9.2. URI Scheme Registration |
| The entries for the "http" and "https" URI Schemes in the registry |  | The entries for the "http" and "https" URI Schemes in the registry |
| located at <http://www.iana.org/assignments/uri-schemes.html> shall |  | located at <http://www.iana.org/assignments/uri-schemes.html> shall |
| be updated to point to Sections 2.7.1 and 2.7.2 of this document (see |  | be updated to point to Sections 2.7.1 and 2.7.2 of this document (see |
| [RFC4395]). |  | [RFC4395]). |
| 10.3. Internet Media Type Registrations |  | 9.3. 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]). |
| 10.3.1. Internet Media Type message/http |  | 9.3.1. Internet Media Type message/http |
| The message/http type can be used to enclose a single HTTP request or |  | The message/http type can be used to enclose a single HTTP request or |
| response message, provided that it obeys the MIME restrictions for |  | response message, provided that it obeys the MIME restrictions for |
| all "message" types regarding line length and encodings. |  | all "message" types regarding line length and encodings. |
| Type name: message |  | Type name: message |
| Subtype name: http |  | Subtype name: http |
| Required parameters: none |  | Required parameters: none |
| skipping to change at page 65, line 28 |  | skipping to change at page 60, line 28 |
| present, the type can be determined from the first line of the |  | present, the type can be determined from the first line of the |
| body. |  | body. |
| Encoding considerations: only "7bit", "8bit", or "binary" are |  | Encoding considerations: only "7bit", "8bit", or "binary" are |
| permitted |  | permitted |
| Security considerations: none |  | Security considerations: none |
| Interoperability considerations: none |  | Interoperability considerations: none |
| Published specification: This specification (see Section 10.3.1). |  | Published specification: This specification (see Section 9.3.1). |
| Applications that use this media type: |  | Applications that use this media type: |
| Additional information: |  | Additional information: |
| Magic number(s): none |  | Magic number(s): none |
| File extension(s): none |  | File extension(s): none |
| Macintosh file type code(s): none |  | Macintosh file type code(s): none |
| Person and email address to contact for further information: See |  | Person and email address to contact for further information: See |
| Authors Section. |  | Authors Section. |
| Intended usage: COMMON |  | Intended usage: COMMON |
| Restrictions on usage: none |  | Restrictions on usage: none |
| Author/Change controller: IESG |  | Author/Change controller: IESG |
| 10.3.2. Internet Media Type application/http |  | 9.3.2. Internet Media Type application/http |
| The application/http type can be used to enclose a pipeline of one or |  | The application/http type can be used to enclose a pipeline of one or |
| more HTTP request or response messages (not intermixed). |  | more HTTP request or response messages (not intermixed). |
| Type name: application |  | Type name: application |
| Subtype name: http |  | Subtype name: http |
| Required parameters: none |  | Required parameters: none |
| skipping to change at page 66, line 34 |  | skipping to change at page 61, line 34 |
| body. |  | body. |
| Encoding considerations: HTTP messages enclosed by this type are in |  | Encoding considerations: HTTP messages enclosed by this type are in |
| "binary" format; use of an appropriate Content-Transfer-Encoding |  | "binary" format; use of an appropriate Content-Transfer-Encoding |
| is required when transmitted via E-mail. |  | is required when transmitted via E-mail. |
| Security considerations: none |  | Security considerations: none |
| Interoperability considerations: none |  | Interoperability considerations: none |
| Published specification: This specification (see Section 10.3.2). |  | Published specification: This specification (see Section 9.3.2). |
| Applications that use this media type: |  | Applications that use this media type: |
| Additional information: |  | Additional information: |
| Magic number(s): none |  | Magic number(s): none |
| File extension(s): none |  | File extension(s): none |
| Macintosh file type code(s): none |  | Macintosh file type code(s): none |
| Person and email address to contact for further information: See |  | Person and email address to contact for further information: See |
| Authors Section. |  | Authors Section. |
| Intended usage: COMMON |  | Intended usage: COMMON |
| Restrictions on usage: none |  | Restrictions on usage: none |
| Author/Change controller: IESG |  | Author/Change controller: IESG |
| 10.4. Transfer Coding Registry |  | 9.4. Transfer Coding Registry |
| The registration procedure for HTTP Transfer Codings is now defined |  | The registration procedure for HTTP Transfer Codings is now defined |
| by Section 6.2.3 of this document. |  | by Section 5.1.3 of this document. |
| The HTTP Transfer Codings Registry located at |  | The HTTP Transfer Codings Registry located at |
| <http://www.iana.org/assignments/http-parameters> shall be updated |  | <http://www.iana.org/assignments/http-parameters> shall be updated |
| with the registrations below: |  | with the registrations below: |
| +----------+--------------------------------------+-----------------+ |  | +----------+--------------------------------------+-----------------+ |
| | Name | Description | Reference | |  | | Name | Description | Reference | |
| +----------+--------------------------------------+-----------------+ |  | +----------+--------------------------------------+-----------------+ |
| | chunked | Transfer in a series of chunks | Section 6.2.1 | |  | | chunked | Transfer in a series of chunks | Section 5.1.1 | |
| | compress | UNIX "compress" program method | Section 6.2.2.1 | |  | | compress | UNIX "compress" program method | Section 5.1.2.1 | |
| | deflate | "deflate" compression mechanism | Section 6.2.2.2 | |  | | deflate | "deflate" compression mechanism | Section 5.1.2.2 | |
| | | ([RFC1951]) used inside the "zlib" | | |  | | | ([RFC1951]) used inside the "zlib" | | |
| | | data format ([RFC1950]) | | |  | | | data format ([RFC1950]) | | |
| | gzip | Same as GNU zip [RFC1952] | Section 6.2.2.3 | |  | | gzip | Same as GNU zip [RFC1952] | Section 5.1.2.3 | |
| +----------+--------------------------------------+-----------------+ |  | +----------+--------------------------------------+-----------------+ |
| 10.5. Upgrade Token Registration |  | 9.5. Upgrade Token Registration |
| The registration procedure for HTTP Upgrade Tokens -- previously |  | The registration procedure for HTTP Upgrade Tokens -- previously |
| defined in Section 7.2 of [RFC2817] -- is now defined by |  | defined in Section 7.2 of [RFC2817] -- is now defined by |
| Section 9.8.1 of this document. |  | Section 8.7.1 of this document. |
| The HTTP Status Code Registry located at |  | The HTTP Status Code Registry located at |
| <http://www.iana.org/assignments/http-upgrade-tokens/> shall be |  | <http://www.iana.org/assignments/http-upgrade-tokens/> shall be |
| updated with the registration below: |  | updated with the registration below: |
| +-------+---------------------------+-------------------------------+ |  | +-------+---------------------------+-------------------------------+ |
| | Value | Description | Reference | |  | | Value | Description | Reference | |
| +-------+---------------------------+-------------------------------+ |  | +-------+---------------------------+-------------------------------+ |
| | HTTP | Hypertext Transfer | Section 2.6 of this | |  | | HTTP | Hypertext Transfer | Section 2.6 of this | |
| | | Protocol | specification | |  | | | Protocol | specification | |
| +-------+---------------------------+-------------------------------+ |  | +-------+---------------------------+-------------------------------+ |
| 11. Security Considerations |  | 10. 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. |
| 11.1. Personal Information |  | 10.1. Personal Information |
| HTTP clients are often privy to large amounts of personal information |  | HTTP clients are often privy to large amounts of personal information |
| (e.g., the user's name, location, mail address, passwords, encryption |  | (e.g., the user's name, location, mail address, passwords, encryption |
| keys, etc.), and SHOULD be very careful to prevent unintentional |  | keys, etc.), and SHOULD be very careful to prevent unintentional |
| leakage of this information. We very strongly recommend that a |  | leakage of this information. We very strongly recommend that a |
| convenient interface be provided for the user to control |  | convenient interface be provided for the user to control |
| dissemination of such information, and that designers and |  | dissemination of such information, and that designers and |
| implementors be particularly careful in this area. History shows |  | implementors be particularly careful in this area. History shows |
| that errors in this area often create serious security and/or privacy |  | that errors in this area often create serious security and/or privacy |
| problems and generate highly adverse publicity for the implementor's |  | problems and generate highly adverse publicity for the implementor's |
| company. |  | company. |
| 11.2. Abuse of Server Log Information |  | 10.2. 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. This information is clearly confidential in nature and its |  | interest. This information is clearly confidential in nature and its |
| handling can be constrained by law in certain countries. People |  | handling can be constrained by law in certain countries. People |
| using HTTP to provide data are responsible for ensuring that such |  | using HTTP to provide data are responsible for ensuring that such |
| material is not distributed without the permission of any individuals |  | material is not distributed without the permission of any individuals |
| that are identifiable by the published results. |  | that are identifiable by the published results. |
| 11.3. Attacks Based On File and Path Names |  | 10.3. Attacks Based On File and Path Names |
| Implementations of HTTP origin servers SHOULD be careful to restrict |  | Implementations of HTTP origin servers SHOULD be careful to restrict |
| the documents returned by HTTP requests to be only those that were |  | the documents returned by HTTP requests to be only those that were |
| intended by the server administrators. If an HTTP server translates |  | intended by the server administrators. If an HTTP server translates |
| HTTP URIs directly into file system calls, the server MUST take |  | HTTP URIs directly into file system calls, the server MUST take |
| special care not to serve files that were not intended to be |  | special care not to serve files that were not intended to be |
| delivered to HTTP clients. For example, UNIX, Microsoft Windows, and |  | delivered to HTTP clients. For example, UNIX, Microsoft Windows, and |
| other operating systems use ".." as a path component to indicate a |  | other operating systems use ".." as a path component to indicate a |
| directory level above the current one. On such a system, an HTTP |  | directory level above the current one. On such a system, an HTTP |
| server MUST disallow any such construct in the request-target if it |  | server MUST disallow any such construct in the request-target if it |
| would otherwise allow access to a resource outside those intended to |  | would otherwise allow access to a resource outside those intended to |
| be accessible via the HTTP server. Similarly, files intended for |  | be accessible via the HTTP server. Similarly, files intended for |
| reference only internally to the server (such as access control |  | reference only internally to the server (such as access control |
| files, configuration files, and script code) MUST be protected from |  | files, configuration files, and script code) MUST be protected from |
| inappropriate retrieval, since they might contain sensitive |  | inappropriate retrieval, since they might contain sensitive |
| information. Experience has shown that minor bugs in such HTTP |  | information. Experience has shown that minor bugs in such HTTP |
| server implementations have turned into security risks. |  | server implementations have turned into security risks. |
| 11.4. DNS-related Attacks |  | 10.4. 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]). |
| 11.5. Proxies and Caching |  | 10.5. Proxies and Caching |
| By their very nature, HTTP proxies are men-in-the-middle, and |  | By their very nature, HTTP proxies are men-in-the-middle, and |
| represent an opportunity for man-in-the-middle attacks. Compromise |  | represent an opportunity for man-in-the-middle attacks. Compromise |
| of the systems on which the proxies run can result in serious |  | of the systems on which the proxies run can result in serious |
| security and privacy problems. Proxies have access to security- |  | security and privacy problems. Proxies have access to security- |
| related information, personal information about individual users and |  | related information, personal information about individual users and |
| organizations, and proprietary information belonging to users and |  | organizations, and proprietary information belonging to users and |
| content providers. A compromised proxy, or a proxy implemented or |  | content providers. A compromised proxy, or a proxy implemented or |
| configured without regard to security and privacy considerations, |  | configured without regard to security and privacy considerations, |
| might be used in the commission of a wide range of potential attacks. |  | might be used in the commission of a wide range of potential attacks. |
| Proxy operators need to protect the systems on which proxies run as |  | Proxy operators need to protect the systems on which proxies run as |
| they would protect any system that contains or transports sensitive |  | they would protect any system that contains or transports sensitive |
| information. In particular, log information gathered at proxies |  | information. In particular, log information gathered at proxies |
| often contains highly sensitive personal information, and/or |  | often contains highly sensitive personal information, and/or |
| information about organizations. Log information needs to be |  | information about organizations. Log information needs to be |
| carefully guarded, and appropriate guidelines for use need to be |  | carefully guarded, and appropriate guidelines for use need to be |
| developed and followed. (Section 11.2). |  | developed and followed. (Section 10.2). |
| Proxy implementors need to consider the privacy and security |  | Proxy implementors need to consider the privacy and security |
| implications of their design and coding decisions, and of the |  | implications of their design and coding decisions, and of the |
| configuration options they provide to proxy operators (especially the |  | configuration options they provide to proxy operators (especially the |
| default configuration). |  | default configuration). |
| Users of a proxy need to be aware that proxies are no trustworthier |  | Users of a proxy need to be aware that proxies are no trustworthier |
| than the people who run them; HTTP itself cannot solve this problem. |  | than the people who run them; HTTP itself cannot solve this problem. |
| The judicious use of cryptography, when appropriate, might suffice to |  | The judicious use of cryptography, when appropriate, might suffice to |
| protect against a broad range of security and privacy attacks. Such |  | protect against a broad range of security and privacy attacks. Such |
| cryptography is beyond the scope of the HTTP/1.1 specification. |  | cryptography is beyond the scope of the HTTP/1.1 specification. |
| 11.6. Protocol Element Size Overflows |  | 10.6. 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 size limits on request-targets (Section 4.1.2) |  | recommendations for size limits on request-targets (Section 3.1.1.2) |
| and blocks of header fields (Section 3.2). These are minimum |  | and blocks of header fields (Section 3.2). These are minimum |
| recommendations, chosen to be supportable even by implementations |  | recommendations, chosen to be supportable even by implementations |
| with limited resources; it is expected that most implementations will |  | with limited resources; it is expected that most implementations will |
| choose substantially higher limits. |  | 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 8.4.15 of |  | that have request-targets that are too long (Section 7.4.15 of |
| [Part2]) or request entities that are too large (Section 8.4 of |  | [Part2]) or request entities that are too large (Section 7.4 of |
| [Part2]). |  | [Part2]). |
| Other fields (including but not limited to request methods, response |  | Other fields (including but not limited to request methods, response |
| status phrases, header field-names, and body chunks) SHOULD be |  | status phrases, header field-names, and body chunks) SHOULD be |
| limited by implementations carefully, so as to not impede |  | limited by implementations carefully, so as to not impede |
| interoperability. |  | interoperability. |
| 11.7. Denial of Service Attacks on Proxies |  | 10.7. Denial of Service Attacks on Proxies |
| They exist. They are hard to defend against. Research continues. |  | They exist. They are hard to defend against. Research continues. |
| Beware. |  | Beware. |
| 12. Acknowledgments |  | 11. Acknowledgments |
| This document revision builds on the work that went into RFC 2616 and |  | This document revision builds on the work that went into RFC 2616 and |
| its predecessors. See Section 16 of [RFC2616] for detailed |  | its predecessors. See Section 16 of [RFC2616] for detailed |
| acknowledgements. |  | acknowledgements. |
| [[todoacks: Insert HTTPbis-specific acknowledgements here.]] |  | Since 1999, many contributors have helped by reporting bugs, asking |
|  |  | smart questions, drafting and reviewing text, and discussing open |
|  |  | issues: |
| 13. References |  | Adam Barth, Adam Roach, Addison Phillips, Adrian Chadd, Adrien de |
|  |  | Croy, Alan Ford, Alan Ruttenberg, Albert Lunde, Alex Rousskov, Alexey |
|  |  | Melnikov, Alisha Smith, Amichai Rothman, Amit Klein, Amos Jeffries, |
|  |  | Andreas Maier, Andreas Petersson, Anne van Kesteren, Anthony Bryan, |
|  |  | Asbjorn Ulsberg, Balachander Krishnamurthy, Barry Leiba, Ben Laurie, |
|  |  | Benjamin Niven-Jenkins, Bil Corry, Bill Burke, Bjoern Hoehrmann, Bob |
|  |  | Scheifler, Boris Zbarsky, Brett Slatkin, Brian Kell, Brian McBarron, |
|  |  | Brian Pane, Brian Smith, Bryce Nesbitt, Carl Kugler, Charles Fry, |
|  |  | Chris Newman, Cyrus Daboo, Dale Robert Anderson, Dan Winship, Daniel |
|  |  | Stenberg, Dave Cridland, Dave Crocker, Dave Kristol, David Booth, |
|  |  | David Singer, David W. Morris, Diwakar Shetty, Drummond Reed, Duane |
|  |  | Wessels, Edward Lee, Eliot Lear, Eran Hammer-Lahav, Eric D. Williams, |
|  |  | Eric J. Bowman, Eric Lawrence, Erik Aronesty, Florian Weimer, Frank |
|  |  | Ellermann, Fred Bohle, Geoffrey Sneddon, Gervase Markham, Greg |
|  |  | Wilkins, Harald Tveit Alvestrand, Harry Halpin, Helge Hess, Henrik |
|  |  | Nordstrom, Henry S. Thompson, Henry Story, Howard Melman, Hugo Haas, |
|  |  | Ian Hickson, Ingo Struck, J. Ross Nicoll, James H. Manger, James |
|  |  | Lacey, James M. Snell, Jamie Lokier, Jan Algermissen, Jeff Hodges |
|  |  | (for coming up with the term 'effective Request-URI'), Jeff Walden, |
|  |  | Jim Luther, Joe D. Williams, Joe Gregorio, Joe Orton, John C. |
|  |  | Klensin, John C. Mallery, John Cowan, John Kemp, John Panzer, John |
|  |  | Schneider, John Stracke, Jonas Sicking, Jonathan Moore, Jonathan |
|  |  | Rees, Jordi Ros, Joris Dobbelsteen, Josh Cohen, Julien Pierre, |
|  |  | Jungshik Shin, Justin Chapweske, Justin Erenkrantz, Justin James, |
|  |  | Kalvinder Singh, Karl Dubost, Keith Hoffman, Keith Moore, Koen |
|  |  | Holtman, Konstantin Voronkov, Kris Zyp, Lisa Dusseault, Maciej |
|  |  | Stachowiak, Marc Schneider, Marc Slemko, Mark Baker, Mark Nottingham |
|  |  | (Working Group chair), Mark Pauley, Martin J. Duerst, Martin Thomson, |
|  |  | Matt Lynch, Matthew Cox, Max Clark, Michael Burrows, Michael |
|  |  | Hausenblas, Mike Amundsen, Mike Kelly, Mike Schinkel, Miles Sabin, |
|  |  | Mykyta Yevstifeyev, Nathan Rixham, Nicholas Shanks, Nico Williams, |
|  |  | Nicolas Alvarez, Noah Slater, Pablo Castro, Pat Hayes, Patrick R. |
|  |  | McManus, Paul E. Jones, Paul Hoffman, Paul Marquess, Peter Saint- |
|  |  | Andre, Peter Watkins, Phil Archer, Phillip Hallam-Baker, Poul-Henning |
|  |  | Kamp, Preethi Natarajan, Reto Bachmann-Gmuer, Richard Cyganiak, |
|  |  | Robert Brewer, Robert Collins, Robert O'Callahan, Robert Olofsson, |
|  |  | Robert Sayre, Robert Siemer, Robert de Wilde, Roberto Javier Godoy, |
|  |  | Ronny Widjaja, S. Mike Dierken, Salvatore Loreto, Sam Johnston, Sam |
|  |  | Ruby, Scott Lawrence (for maintaining the original issues list), Sean |
|  |  | B. Palmer, Shane McCarron, Stefan Eissing, Stefan Tilkov, Stefanos |
|  |  | Harhalakis, Stephane Bortzmeyer, Stuart Williams, Subbu Allamaraju, |
|  |  | Sylvain Hellegouarch, Tapan Divekar, Thomas Broyer, Thomas Nordin, |
|  |  | Thomas Roessler, Tim Morgan, Tim Olsen, Travis Snoozy, Tyler Close, |
|  |  | Vincent Murphy, Wenbo Zhu, Werner Baumann, Wilbur Streett, Wilfredo |
|  |  | Sanchez Vega, William A. Rowe Jr., William Chan, Willy Tarreau, |
|  |  | Xiaoshu Wang, Yaron Goland, Yngve Nysaeter Pettersen, Yogesh Bang, |
|  |  | Yutaka Oiwa, and Zed A. Shaw. |
| 13.1. Normative References |  | 12. References |
|  |  | 12.1. Normative 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. |
| [Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |  | [Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., |
| Ed., and J. Reschke, Ed., "HTTP/1.1, part 2: Message |  | Ed., and J. Reschke, Ed., "HTTP/1.1, part 2: Message |
| Semantics", draft-ietf-httpbis-p2-semantics-16 (work in |  | Semantics", draft-ietf-httpbis-p2-semantics-17 (work in |
| progress), August 2011. |  | progress), October 2011. |
| [Part3] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |  | [Part3] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., |
| Ed., and J. Reschke, Ed., "HTTP/1.1, part 3: Message |  | Ed., and J. Reschke, Ed., "HTTP/1.1, part 3: Message |
| Payload and Content Negotiation", |  | Payload and Content Negotiation", |
| draft-ietf-httpbis-p3-payload-16 (work in progress), |  | draft-ietf-httpbis-p3-payload-17 (work in progress), |
| August 2011. |  | October 2011. |
| [Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |  | [Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., |
| Ed., Nottingham, M., Ed., and J. Reschke, Ed., |  | Ed., Nottingham, M., Ed., and J. Reschke, Ed., |
| "HTTP/1.1, part 6: Caching", |  | "HTTP/1.1, part 6: Caching", |
| draft-ietf-httpbis-p6-cache-16 (work in progress), |  | draft-ietf-httpbis-p6-cache-17 (work in progress), |
| August 2011. |  | October 2011. |
| [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. |
| RFC 1950 is an Informational RFC, thus it might be less |  | RFC 1950 is an Informational RFC, thus it might be less |
| stable than this specification. On the other hand, |  | stable than this specification. On the other hand, |
| this downward reference was present since the |  | this downward reference was present since the |
| publication of RFC 2068 in 1997 ([RFC2068]), therefore |  | publication of RFC 2068 in 1997, therefore it is |
| it is unlikely to cause problems in practice. See also |  | unlikely to cause problems in practice. See also |
| [BCP97]. |  | [BCP97]. |
| [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. |
| RFC 1951 is an Informational RFC, thus it might be less |  | RFC 1951 is an Informational RFC, thus it might be less |
| stable than this specification. On the other hand, |  | stable than this specification. On the other hand, |
| this downward reference was present since the |  | this downward reference was present since the |
| publication of RFC 2068 in 1997 ([RFC2068]), therefore |  | publication of RFC 2068 in 1997, therefore it is |
| it is unlikely to cause problems in practice. See also |  | unlikely to cause problems in practice. See also |
| [BCP97]. |  | [BCP97]. |
| [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. |
| RFC 1952 is an Informational RFC, thus it might be less |  | RFC 1952 is an Informational RFC, thus it might be less |
| stable than this specification. On the other hand, |  | stable than this specification. On the other hand, |
| this downward reference was present since the |  | this downward reference was present since the |
| publication of RFC 2068 in 1997 ([RFC2068]), therefore |  | publication of RFC 2068 in 1997, therefore it is |
| it is unlikely to cause problems in practice. See also |  | unlikely to cause problems in practice. See also |
| [BCP97]. |  | [BCP97]. |
| [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate |  | [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate |
| Requirement Levels", BCP 14, RFC 2119, March 1997. |  | Requirement Levels", BCP 14, RFC 2119, March 1997. |
| [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, |  | [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, |
| "Uniform Resource Identifier (URI): Generic Syntax", |  | "Uniform Resource Identifier (URI): Generic Syntax", |
| STD 66, RFC 3986, January 2005. |  | STD 66, RFC 3986, January 2005. |
| [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for |  | [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for |
| Syntax Specifications: ABNF", STD 68, RFC 5234, |  | Syntax Specifications: ABNF", STD 68, RFC 5234, |
| January 2008. |  | January 2008. |
| [USASCII] American National Standards Institute, "Coded Character |  | [USASCII] American National Standards Institute, "Coded Character |
| Set -- 7-bit American Standard Code for Information |  | Set -- 7-bit American Standard Code for Information |
| Interchange", ANSI X3.4, 1986. |  | Interchange", ANSI X3.4, 1986. |
| 13.2. Informative References |  | 12.2. Informative References |
| [BCP97] Klensin, J. and S. Hartman, "Handling Normative |  | [BCP97] Klensin, J. and S. Hartman, "Handling Normative |
| References to Standards-Track Documents", BCP 97, |  | References to Standards-Track Documents", BCP 97, |
| RFC 4897, June 2007. |  | RFC 4897, June 2007. |
| [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>. |
| skipping to change at page 72, line 30 |  | skipping to change at page 68, line 33 |
| SIGCOMM '97 conference on Applications, technologies, |  | SIGCOMM '97 conference on Applications, technologies, |
| architectures, and protocols for computer communication |  | architectures, and protocols for computer communication |
| SIGCOMM '97, September 1997, |  | SIGCOMM '97, September 1997, |
| <http://doi.acm.org/10.1145/263105.263157>. |  | <http://doi.acm.org/10.1145/263105.263157>. |
| [Pad1995] Padmanabhan, V. and J. Mogul, "Improving HTTP Latency", |  | [Pad1995] Padmanabhan, V. and J. Mogul, "Improving HTTP Latency", |
| Computer Networks and ISDN Systems v. 28, pp. 25-35, |  | Computer Networks and ISDN Systems v. 28, pp. 25-35, |
| December 1995, |  | December 1995, |
| <http://portal.acm.org/citation.cfm?id=219094>. |  | <http://portal.acm.org/citation.cfm?id=219094>. |
| [RFC1123] Braden, R., "Requirements for Internet Hosts - |  |  |
| Application and Support", STD 3, RFC 1123, |  |  |
| October 1989. |  |  |
| [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 75, line 16 |  | skipping to change at page 71, line 14 |
| in the request-target. |  | in the request-target. |
| A.1. Changes from HTTP/1.0 |  | A.1. Changes from HTTP/1.0 |
| This section summarizes major differences between versions HTTP/1.0 |  | This section summarizes major differences between versions HTTP/1.0 |
| and HTTP/1.1. |  | and HTTP/1.1. |
| A.1.1. Multi-homed Web Servers |  | A.1.1. Multi-homed Web Servers |
| The requirements that clients and servers support the Host header |  | The requirements that clients and servers support the Host header |
| field (Section 9.4), report an error if it is missing from an |  | field (Section 8.3), report an error if it is missing from an |
| HTTP/1.1 request, and accept absolute URIs (Section 4.1.2) are among |  | HTTP/1.1 request, and accept absolute URIs (Section 3.1.1.2) are |
| the most important changes defined by HTTP/1.1. |  | among the most important changes defined by HTTP/1.1. |
| Older HTTP/1.0 clients assumed a one-to-one relationship of IP |  | Older HTTP/1.0 clients assumed a one-to-one relationship of IP |
| addresses and servers; there was no other established mechanism for |  | addresses and servers; there was no other established mechanism for |
| distinguishing the intended server of a request than the IP address |  | distinguishing the intended server of a request than the IP address |
| to which that request was directed. The Host header field was |  | to which that request was directed. The Host header field was |
| introduced during the development of HTTP/1.1 and, though it was |  | introduced during the development of HTTP/1.1 and, though it was |
| quickly implemented by most HTTP/1.0 browsers, additional |  | quickly implemented by most HTTP/1.0 browsers, additional |
| requirements were placed on all HTTP/1.1 requests in order to ensure |  | requirements were placed on all HTTP/1.1 requests in order to ensure |
| complete adoption. At the time of this writing, most HTTP-based |  | complete adoption. At the time of this writing, most HTTP-based |
| services are dependent upon the Host header field for targeting |  | services are dependent upon the Host header field for targeting |
| skipping to change at page 76, line 11 |  | skipping to change at page 72, line 9 |
| HTTP/1.0 proxy waiting for the close on the response. The result is |  | HTTP/1.0 proxy waiting for the close on the response. The result is |
| that HTTP/1.0 clients must be prevented from using Keep-Alive when |  | that HTTP/1.0 clients must be prevented from using Keep-Alive when |
| talking to proxies. |  | talking to proxies. |
| However, talking to proxies is the most important use of persistent |  | However, talking to proxies is the most important use of persistent |
| connections, so that prohibition is clearly unacceptable. Therefore, |  | connections, so that prohibition is clearly unacceptable. Therefore, |
| we need some other mechanism for indicating a persistent connection |  | we need some other mechanism for indicating a persistent connection |
| is desired, which is safe to use even when talking to an old proxy |  | is desired, which is safe to use even when talking to an old proxy |
| that ignores Connection. Persistent connections are the default for |  | that ignores Connection. Persistent connections are the default for |
| HTTP/1.1 messages; we introduce a new keyword (Connection: close) for |  | HTTP/1.1 messages; we introduce a new keyword (Connection: close) for |
| declaring non-persistence. See Section 9.1. |  | declaring non-persistence. See Section 8.1. |
| A.2. Changes from RFC 2616 |  | A.2. Changes from RFC 2616 |
| Empty list elements in list productions have been deprecated. |  | Empty list elements in list productions have been deprecated. |
| (Section 1.2.1) |  | (Section 1.2.1) |
| Rules about implicit linear whitespace between certain grammar |  | Rules about implicit linear whitespace between certain grammar |
| productions have been removed; now it's only allowed when |  | productions have been removed; now it's only allowed when |
| specifically pointed out in the ABNF. (Section 1.2.2) |  | specifically pointed out in the ABNF. (Section 1.2.2) |
| skipping to change at page 76, line 40 |  | skipping to change at page 72, line 38 |
| 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 3.2.3) |  | removed). (Section 3.2.3) |
| Require recipients to handle bogus Content-Length header fields as |  | Require recipients to handle bogus Content-Length header fields as |
| errors. (Section 3.3) |  | errors. (Section 3.3) |
| Remove reference to non-existent identity transfer-coding value |  | Remove reference to non-existent identity transfer-coding value |
| tokens. (Sections 3.3 and 6.2) |  | tokens. (Sections 3.3 and 5.1) |
| Update use of abs_path production from RFC 1808 to the path-absolute |  | Update use of abs_path production from RFC 1808 to the path-absolute |
| + query components of RFC 3986. State that the asterisk form is |  | + query components of RFC 3986. State that the asterisk form is |
| allowed for the OPTIONS request method only. (Section 4.1.2) |  | allowed for the OPTIONS request method only. (Section 3.1.1.2) |
| 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. (Section 6.2.1) |  | folding in chunk extensions. (Section 5.1.1) |
| Remove hard limit of two connections per server. (Section 7.1.4) |  | Remove hard limit of two connections per server. Remove requirement |
|  |  | to retry a sequence of requests as long it was idempotent. Remove |
|  |  | requirements about when servers are allowed to close connections |
|  |  | prematurely. (Section 6.1.4) |
|  |  | Remove requirement to retry requests under certain cirumstances when |
|  |  | the server prematurely closes the connection. (Section 6.2) |
| Change ABNF productions for header fields to only define the field |  | Change ABNF productions for header fields to only define the field |
| value. (Section 9) |  | value. (Section 8) |
| Clarify exactly when close connection options must be sent. |  | Clarify exactly when close connection options must be sent. |
| (Section 9.1) |  | (Section 8.1) |
| 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 9.8) |  | than 101 (this was incorporated from [RFC2817]). (Section 8.7) |
| Appendix B. Collected ABNF |  | Appendix B. Collected ABNF |
| BWS = OWS |  | BWS = OWS |
| Chunked-Body = *chunk last-chunk trailer-part CRLF |  | Chunked-Body = *chunk last-chunk trailer-part CRLF |
| Connection = *( "," OWS ) connection-token *( OWS "," [ OWS |  | Connection = *( "," OWS ) connection-token *( OWS "," [ OWS |
| connection-token ] ) |  | connection-token ] ) |
| Content-Length = 1*DIGIT |  | Content-Length = 1*DIGIT |
| Date = HTTP-date |  |  |
| GMT = %x47.4D.54 ; GMT |  |  |
| HTTP-Prot-Name = %x48.54.54.50 ; HTTP |  | HTTP-Prot-Name = %x48.54.54.50 ; HTTP |
| HTTP-Version = HTTP-Prot-Name "/" DIGIT "." DIGIT |  | HTTP-Version = HTTP-Prot-Name "/" DIGIT "." DIGIT |
| HTTP-date = rfc1123-date / obs-date |  |  |
| HTTP-message = start-line *( header-field CRLF ) CRLF [ message-body |  | HTTP-message = start-line *( header-field CRLF ) CRLF [ message-body |
| ] |  | ] |
| Host = uri-host [ ":" port ] |  | Host = uri-host [ ":" port ] |
| Method = token |  | Method = token |
| OWS = *( [ obs-fold ] WSP ) |  | OWS = *( SP / HTAB / obs-fold ) |
| RWS = 1*( [ obs-fold ] WSP ) |  | RWS = 1*( SP / HTAB / obs-fold ) |
| Reason-Phrase = *( WSP / VCHAR / obs-text ) |  | Reason-Phrase = *( HTAB / SP / VCHAR / obs-text ) |
| Request = Request-Line *( header-field CRLF ) CRLF [ message-body ] |  |  |
| Request-Line = Method SP request-target SP HTTP-Version CRLF |  | Request-Line = Method SP request-target SP HTTP-Version CRLF |
| Response = Status-Line *( header-field CRLF ) CRLF [ message-body ] |  |  |
| 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 |
| TE = [ ( "," / t-codings ) *( OWS "," [ OWS t-codings ] ) ] |  | TE = [ ( "," / t-codings ) *( OWS "," [ OWS t-codings ] ) ] |
| Trailer = *( "," OWS ) field-name *( OWS "," [ OWS field-name ] ) |  | Trailer = *( "," OWS ) field-name *( OWS "," [ OWS field-name ] ) |
| Transfer-Encoding = *( "," OWS ) transfer-coding *( OWS "," [ OWS |  | Transfer-Encoding = *( "," OWS ) transfer-coding *( OWS "," [ OWS |
| transfer-coding ] ) |  | transfer-coding ] ) |
| URI-reference = <URI-reference, defined in [RFC3986], Section 4.1> |  | URI-reference = <URI-reference, defined in [RFC3986], Section 4.1> |
| Upgrade = *( "," OWS ) product *( OWS "," [ OWS product ] ) |  | Upgrade = *( "," OWS ) product *( OWS "," [ OWS product ] ) |
| Via = *( "," OWS ) received-protocol RWS received-by [ RWS comment ] |  | Via = *( "," OWS ) received-protocol RWS received-by [ RWS comment ] |
| *( OWS "," [ OWS received-protocol RWS received-by [ RWS comment ] ] |  | *( OWS "," [ OWS received-protocol RWS received-by [ RWS comment ] ] |
| ) |  | ) |
| absolute-URI = <absolute-URI, defined in [RFC3986], Section 4.3> |  | absolute-URI = <absolute-URI, defined in [RFC3986], Section 4.3> |
| asctime-date = day-name SP date3 SP time-of-day SP year |  |  |
| attribute = token |  | attribute = token |
| authority = <authority, defined in [RFC3986], Section 3.2> |  | authority = <authority, defined in [RFC3986], Section 3.2> |
| chunk = chunk-size *WSP [ chunk-ext ] CRLF chunk-data CRLF |  | chunk = chunk-size [ chunk-ext ] CRLF chunk-data CRLF |
| chunk-data = 1*OCTET |  | chunk-data = 1*OCTET |
| chunk-ext = *( ";" *WSP chunk-ext-name [ "=" chunk-ext-val ] *WSP ) |  | chunk-ext = *( ";" chunk-ext-name [ "=" chunk-ext-val ] ) |
| chunk-ext-name = token |  | chunk-ext-name = token |
| chunk-ext-val = token / quoted-str-nf |  | chunk-ext-val = token / quoted-str-nf |
| chunk-size = 1*HEXDIG |  | chunk-size = 1*HEXDIG |
| comment = "(" *( ctext / quoted-cpair / comment ) ")" |  | comment = "(" *( ctext / quoted-cpair / comment ) ")" |
| connection-token = token |  | connection-token = token |
| ctext = OWS / %x21-27 ; '!'-''' |  | ctext = OWS / %x21-27 ; '!'-''' |
| / %x2A-5B ; '*'-'[' |  | / %x2A-5B ; '*'-'[' |
| / %x5D-7E ; ']'-'~' |  | / %x5D-7E ; ']'-'~' |
| / obs-text |  | / obs-text |
| date1 = day SP month SP year |  | field-content = *( HTAB / SP / VCHAR / obs-text ) |
| date2 = day "-" month "-" 2DIGIT |  |  |
| date3 = month SP ( 2DIGIT / ( SP DIGIT ) ) |  |  |
| day = 2DIGIT |  |  |
| day-name = %x4D.6F.6E ; Mon |  |  |
| / %x54.75.65 ; Tue |  |  |
| / %x57.65.64 ; Wed |  |  |
| / %x54.68.75 ; Thu |  |  |
| / %x46.72.69 ; Fri |  |  |
| / %x53.61.74 ; Sat |  |  |
| / %x53.75.6E ; Sun |  |  |
| day-name-l = %x4D.6F.6E.64.61.79 ; Monday |  |  |
| / %x54.75.65.73.64.61.79 ; Tuesday |  |  |
| / %x57.65.64.6E.65.73.64.61.79 ; Wednesday |  |  |
| / %x54.68.75.72.73.64.61.79 ; Thursday |  |  |
| / %x46.72.69.64.61.79 ; Friday |  |  |
| / %x53.61.74.75.72.64.61.79 ; Saturday |  |  |
| / %x53.75.6E.64.61.79 ; Sunday |  |  |
| field-content = *( WSP / VCHAR / obs-text ) |  |  |
| field-name = token |  | field-name = token |
| field-value = *( field-content / OWS ) |  | field-value = *( field-content / obs-fold ) |
| header-field = field-name ":" OWS [ field-value ] OWS |  | header-field = field-name ":" OWS field-value BWS |
| hour = 2DIGIT |  |  |
| http-URI = "http://" authority path-abempty [ "?" query ] |  | http-URI = "http://" authority path-abempty [ "?" query ] |
| https-URI = "https://" authority path-abempty [ "?" query ] |  | https-URI = "https://" authority path-abempty [ "?" query ] |
| last-chunk = 1*"0" *WSP [ chunk-ext ] CRLF |  | last-chunk = 1*"0" [ chunk-ext ] CRLF |
| message-body = *OCTET |  | message-body = *OCTET |
| minute = 2DIGIT |  |  |
| month = %x4A.61.6E ; Jan |  |  |
| / %x46.65.62 ; Feb |  |  |
| / %x4D.61.72 ; Mar |  |  |
| / %x41.70.72 ; Apr |  |  |
| / %x4D.61.79 ; May |  |  |
| / %x4A.75.6E ; Jun |  |  |
| / %x4A.75.6C ; Jul |  |  |
| / %x41.75.67 ; Aug |  |  |
| / %x53.65.70 ; Sep |  |  |
| / %x4F.63.74 ; Oct |  |  |
| / %x4E.6F.76 ; Nov |  |  |
| / %x44.65.63 ; Dec |  |  |
| obs-date = rfc850-date / asctime-date |  | obs-fold = CRLF ( SP / HTAB ) |
| obs-fold = CRLF |  |  |
| obs-text = %x80-FF |  | obs-text = %x80-FF |
| partial-URI = relative-part [ "?" query ] |  | partial-URI = relative-part [ "?" query ] |
| 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> |
| product = token [ "/" product-version ] |  | product = token [ "/" product-version ] |
| product-version = token |  | product-version = token |
| protocol-name = token |  | protocol-name = token |
| protocol-version = token |  | protocol-version = token |
| skipping to change at page 79, line 36 |  | skipping to change at page 75, line 4 |
| partial-URI = relative-part [ "?" query ] |  | partial-URI = relative-part [ "?" query ] |
| 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> |
| product = token [ "/" product-version ] |  | product = token [ "/" product-version ] |
| product-version = token |  | product-version = token |
| protocol-name = token |  | protocol-name = token |
| protocol-version = token |  | protocol-version = token |
| pseudonym = token |  | pseudonym = token |
| qdtext = OWS / "!" / %x23-5B ; '#'-'[' |  | qdtext = OWS / "!" / %x23-5B ; '#'-'[' |
| / %x5D-7E ; ']'-'~' |  | / %x5D-7E ; ']'-'~' |
| / obs-text |  | / obs-text |
| qdtext-nf = WSP / "!" / %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 = "\" ( WSP / VCHAR / obs-text ) |  | quoted-cpair = "\" ( HTAB / SP / VCHAR / obs-text ) |
| quoted-pair = "\" ( WSP / 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" ] ) |  | qvalue = ( "0" [ "." *3DIGIT ] ) / ( "1" [ "." *3"0" ] ) |
| 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-target = "*" / absolute-URI / ( path-absolute [ "?" query ] ) |  | request-target = "*" / absolute-URI / ( path-absolute [ "?" query ] ) |
| / authority |  | / authority |
| rfc1123-date = day-name "," SP date1 SP time-of-day SP GMT |  |  |
| rfc850-date = day-name-l "," SP date2 SP time-of-day SP GMT |  |  |
| second = 2DIGIT |  |  |
| special = "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "\" / |  | special = "(" / ")" / "<" / ">" / "@" / "," / ";" / ":" / "\" / |
| DQUOTE / "/" / "[" / "]" / "?" / "=" / "{" / "}" |  | DQUOTE / "/" / "[" / "]" / "?" / "=" / "{" / "}" |
| start-line = Request-Line / Status-Line |  | start-line = Request-Line / Status-Line |
| t-codings = "trailers" / ( transfer-extension [ te-params ] ) |  | t-codings = "trailers" / ( transfer-extension [ te-params ] ) |
| tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." / |  | tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" / "." / |
| "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA |  | "^" / "_" / "`" / "|" / "~" / DIGIT / ALPHA |
| te-ext = OWS ";" OWS token [ "=" word ] |  | te-ext = OWS ";" OWS token [ "=" word ] |
| te-params = OWS ";" OWS "q=" qvalue *te-ext |  | te-params = OWS ";" OWS "q=" qvalue *te-ext |
| time-of-day = hour ":" minute ":" second |  |  |
| 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 |
| year = 4DIGIT |  |  |
| ABNF diagnostics: |  | ABNF diagnostics: |
| ; Chunked-Body defined but not used |  | ; Chunked-Body defined but not used |
| ; Connection defined but not used |  | ; Connection defined but not used |
| ; Content-Length defined but not used |  | ; Content-Length defined but not used |
| ; Date defined but not used |  |  |
| ; HTTP-message defined but not used |  | ; HTTP-message defined but not used |
| ; Host defined but not used |  | ; Host defined but not used |
| ; Request defined but not used |  |  |
| ; Response defined but not used |  |  |
| ; TE defined but not used |  | ; TE defined but not used |
| ; Trailer defined but not used |  | ; Trailer defined but not used |
| ; Transfer-Encoding defined but not used |  | ; Transfer-Encoding defined but not used |
| ; URI-reference defined but not used |  | ; URI-reference defined but not used |
| ; Upgrade defined but not used |  | ; Upgrade defined but not used |
| ; Via defined but not used |  | ; Via defined but not used |
| ; http-URI defined but not used |  | ; http-URI defined but not used |
| ; https-URI defined but not used |  | ; https-URI defined but not used |
| ; partial-URI defined but not used |  | ; partial-URI defined but not used |
| ; special defined but not used |  | ; special defined but not used |
| skipping to change at page 82, line 51 |  | skipping to change at page 77, line 48 |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/66>: "ISO-8859-1 |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/66>: "ISO-8859-1 |
| Reference" |  | Reference" |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/86>: "Normative up- |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/86>: "Normative up- |
| to-date references" |  | to-date references" |
| Other changes: |  | Other changes: |
| o Update media type registrations to use RFC4288 template. |  | o Update media type registrations to use RFC4288 template. |
| o Use names of RFC4234 core rules DQUOTE and WSP, fix broken ABNF |  | o Use names of RFC4234 core rules DQUOTE and HTAB, fix broken ABNF |
| for chunk-data (work in progress on |  | for chunk-data (work in progress on |
| <http://tools.ietf.org/wg/httpbis/trac/ticket/36>) |  | <http://tools.ietf.org/wg/httpbis/trac/ticket/36>) |
| C.3. Since draft-ietf-httpbis-p1-messaging-01 |  | C.3. Since draft-ietf-httpbis-p1-messaging-01 |
| Closed issues: |  | Closed issues: |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/19>: "Bodies on GET |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/19>: "Bodies on GET |
| (and other) requests" |  | (and other) requests" |
| skipping to change at page 91, line 11 |  | skipping to change at page 86, line 11 |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/254>: "move RFCs |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/254>: "move RFCs |
| 2145, 2616, 2817 to Historic status" |  | 2145, 2616, 2817 to Historic status" |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/270>: "\-escaping in |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/270>: "\-escaping in |
| quoted strings" |  | quoted strings" |
| o <http://tools.ietf.org/wg/httpbis/trac/ticket/305>: "'Close' |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/305>: "'Close' |
| should be reserved in the HTTP header field registry" |  | should be reserved in the HTTP header field registry" |
|  |  | C.18. Since draft-ietf-httpbis-p1-messaging-16 |
|  |  | Closed issues: |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/186>: "Document |
|  |  | HTTP's error-handling philosophy" |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/215>: "Explain |
|  |  | header registration" |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/219>: "Revise |
|  |  | Acknowledgements Sections" |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/297>: "Retrying |
|  |  | Requests" |
|  |  | o <http://tools.ietf.org/wg/httpbis/trac/ticket/318>: "Closing the |
|  |  | connection on server error" |
| Index |  | Index |
| A |  | A |
| absolute-URI form (of request-target) 30 |  | absolute-URI form (of request-target) 31 |
| accelerator 13 |  | accelerator 13 |
| application/http Media Type 66 |  | application/http Media Type 61 |
| asterisk form (of request-target) 30 |  | asterisk form (of request-target) 31 |
| authority form (of request-target) 31 |  | authority form (of request-target) 32 |
| B |  | B |
| browser 9 |  | browser 10 |
| C |  | C |
| cache 14 |  | cache 14 |
| cacheable 14 |  | cacheable 15 |
| captive portal 14 |  | captive portal 14 |
| chunked (Coding Format) 39 |  | chunked (Coding Format) 36 |
| client 9 |  | client 10 |
| Coding Format |  | Coding Format |
| chunked 39 |  | chunked 36 |
| compress 42 |  | compress 38 |
| deflate 42 |  | deflate 38 |
| gzip 42 |  | gzip 39 |
| compress (Coding Format) 42 |  |  |
| connection 9 |  | compress (Coding Format) 38 |
| Connection header field 53 |  | connection 10 |
| Content-Length header field 55 |  | Connection header field 49 |
|  |  | Content-Length header field 51 |
| D |  | D |
| Date header field 55 |  | deflate (Coding Format) 38 |
| deflate (Coding Format) 42 |  | downstream 13 |
| downstream 12 |  |  |
| E |  | E |
| effective request URI 33 |  | effective request URI 34 |
| G |  | G |
| gateway 13 |  | gateway 13 |
| Grammar |  | Grammar |
| absolute-URI 17 |  | absolute-URI 17 |
| ALPHA 7 |  | ALPHA 7 |
| asctime-date 38 |  | attribute 35 |
| attribute 38 |  |  |
| authority 17 |  | authority 17 |
| BWS 9 |  | BWS 9 |
| chunk 39 |  | chunk 36 |
| chunk-data 39 |  | chunk-data 36 |
| chunk-ext 39 |  | chunk-ext 36 |
| chunk-ext-name 39 |  | chunk-ext-name 36 |
| chunk-ext-val 39 |  | chunk-ext-val 36 |
| chunk-size 39 |  | chunk-size 36 |
| Chunked-Body 39 |  | Chunked-Body 36 |
| comment 25 |  | comment 26 |
| Connection 54 |  | Connection 50 |
| connection-token 54 |  | connection-token 50 |
| Content-Length 55 |  | Content-Length 51 |
| CR 7 |  | CR 7 |
| CRLF 7 |  | CRLF 7 |
| ctext 25 |  | ctext 26 |
| CTL 7 |  | CTL 7 |
| Date 55 |  | date2 35 |
| date1 37 |  | date3 35 |
| date2 38 |  |  |
| date3 38 |  |  |
| day 37 |  |  |
| day-name 37 |  |  |
| day-name-l 37 |  |  |
| DIGIT 7 |  | DIGIT 7 |
| DQUOTE 7 |  | DQUOTE 7 |
| field-content 22 |  | field-content 23 |
| field-name 22 |  | field-name 23 |
| field-value 22 |  | field-value 23 |
| GMT 37 |  | header-field 23 |
| header-field 22 |  |  |
| HEXDIG 7 |  | HEXDIG 7 |
| Host 57 |  | Host 52 |
| hour 37 |  | HTAB 7 |
| HTTP-date 36 |  |  |
| HTTP-message 21 |  | HTTP-message 21 |
| HTTP-Prot-Name 15 |  | HTTP-Prot-Name 15 |
| http-URI 18 |  | http-URI 18 |
| HTTP-Version 15 |  | HTTP-Version 15 |
| https-URI 19 |  | https-URI 19 |
| last-chunk 39 |  | last-chunk 36 |
| LF 7 |  | LF 7 |
| message-body 25 |  | message-body 27 |
| Method 30 |  | Method 22 |
| minute 37 |  | obs-text 26 |
| month 37 |  |  |
| obs-date 37 |  |  |
| obs-text 24 |  |  |
| OCTET 7 |  | OCTET 7 |
| OWS 9 |  | OWS 9 |
| path-absolute 17 |  | path-absolute 17 |
| port 17 |  | port 17 |
| product 43 |  | product 39 |
| product-version 43 |  | product-version 39 |
| protocol-name 62 |  | protocol-name 57 |
| protocol-version 62 |  | protocol-version 57 |
| pseudonym 62 |  | pseudonym 57 |
| qdtext 24 |  | qdtext 26 |
| qdtext-nf 39 |  | qdtext-nf 36 |
| query 17 |  | query 17 |
| quoted-cpair 25 |  | quoted-cpair 26 |
| quoted-pair 25 |  | quoted-pair 26 |
| quoted-str-nf 39 |  | quoted-str-nf 36 |
| quoted-string 24 |  | quoted-string 26 |
| qvalue 43 |  | qvalue 40 |
| Reason-Phrase 35 |  | Reason-Phrase 23 |
| received-by 62 |  | received-by 57 |
| received-protocol 62 |  | received-protocol 57 |
| Request 29 |  | Request-Line 22 |
| Request-Line 30 |  | request-target 22 |
| request-target 30 |  |  |
| Response 34 |  |  |
| rfc850-date 38 |  |  |
| rfc1123-date 37 |  |  |
| RWS 9 |  | RWS 9 |
| second 37 |  |  |
| SP 7 |  | SP 7 |
| special 24 |  | special 26 |
| Status-Code 35 |  | start-line 21 |
| Status-Line 35 |  | Status-Code 23 |
| t-codings 58 |  | Status-Line 23 |
| tchar 24 |  | t-codings 53 |
| TE 58 |  | tchar 26 |
| te-ext 58 |  | TE 53 |
| te-params 58 |  | te-ext 53 |
| time-of-day 37 |  | te-params 53 |
| token 24 |  | token 26 |
| Trailer 59 |  | Trailer 54 |
| trailer-part 39 |  | trailer-part 36 |
| transfer-coding 38 |  | transfer-coding 35 |
| Transfer-Encoding 60 |  | Transfer-Encoding 54 |
| transfer-extension 38 |  | transfer-extension 35 |
| transfer-parameter 38 |  | transfer-parameter 35 |
| Upgrade 60 |  | Upgrade 55 |
| uri-host 17 |  | uri-host 17 |
| URI-reference 17 |  | URI-reference 17 |
| value 38 |  | value 35 |
| VCHAR 7 |  | VCHAR 7 |
| Via 62 |  | Via 57 |
| word 24 |  | word 26 |
| WSP 7 |  | gzip (Coding Format) 39 |
| year 37 |  |  |
| gzip (Coding Format) 42 |  |  |
| H |  | H |
| header field 20 |  | header field 20 |
| Header Fields |  | Header Fields |
| Connection 53 |  | Connection 49 |
| Content-Length 55 |  | Content-Length 51 |
| Date 55 |  | Host 51 |
| Host 57 |  | TE 53 |
| TE 58 |  | Trailer 54 |
| Trailer 59 |  | Transfer-Encoding 54 |
| Transfer-Encoding 59 |  | Upgrade 55 |
| Upgrade 60 |  | Via 57 |
| Via 62 |  |  |
| header section 20 |  | header section 20 |
| headers 20 |  | headers 20 |
| Host header field 57 |  | Host header field 51 |
| http URI scheme 18 |  | http URI scheme 18 |
| https URI scheme 19 |  | https URI scheme 19 |
| I |  | I |
| inbound 12 |  | inbound 13 |
| interception proxy 14 |  | interception proxy 14 |
| intermediary 12 |  | intermediary 12 |
| M |  | M |
| Media Type |  | Media Type |
| application/http 66 |  | application/http 61 |
| message/http 64 |  | message/http 59 |
| message 10 |  | message 10 |
| message/http Media Type 64 |  | message/http Media Type 59 |
| N |  | N |
| non-transforming proxy 13 |  | non-transforming proxy 13 |
| O |  | O |
| origin form (of request-target) 31 |  | origin form (of request-target) 32 |
| origin server 9 |  | origin server 10 |
| outbound 12 |  | outbound 13 |
| P |  | P |
| proxy 12 |  | proxy 13 |
| R |  | R |
| recipient 9 |  | recipient 10 |
| request 10 |  | request 10 |
| resource 17 |  | resource 17 |
| response 10 |  | response 10 |
| reverse proxy 13 |  | reverse proxy 13 |
| S |  | S |
| sender 9 |  | sender 10 |
| server 9 |  | server 10 |
| spider 9 |  | spider 10 |
| T |  | T |
| target resource 33 |  | target resource 34 |
| TE header field 58 |  | TE header field 53 |
| Trailer header field 59 |  | Trailer header field 54 |
| Transfer-Encoding header field 59 |  | Transfer-Encoding header field 54 |
| transforming proxy 13 |  | transforming proxy 13 |
| transparent proxy 14 |  | transparent proxy 14 |
| tunnel 13 |  | tunnel 14 |
| U |  | U |
| Upgrade header field 60 |  | Upgrade header field 55 |
| upstream 12 |  | upstream 13 |
| URI scheme |  | URI scheme |
| http 18 |  | http 18 |
| https 19 |  | https 19 |
| user agent 9 |  | user agent 10 |
| V |  | V |
| Via header field 62 |  | Via header field 57 |
| 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 |
End of changes. 244 change blocks.
| 912 lines changed or deleted |  | 701 lines changed or added |
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