| draft-ietf-httpbis-p3-payload-01.txt |  | draft-ietf-httpbis-p3-payload-02.txt |
--- | --- | --- | --- | ---
| Network Working Group R. Fielding, Ed. |  | Network Working Group R. Fielding, Ed. |
| Internet-Draft Day Software |  | Internet-Draft Day Software |
| Obsoletes: 2616 (if approved) J. Gettys |  | Obsoletes: 2616 (if approved) J. Gettys |
| Intended status: Standards Track One Laptop per Child |  | Intended status: Standards Track One Laptop per Child |
| Expires: July 15, 2008 J. Mogul |  | Expires: August 27, 2008 J. Mogul |
| HP |  | HP |
| H. Frystyk |  | H. Frystyk |
| Microsoft |  | Microsoft |
| L. Masinter |  | L. Masinter |
| Adobe Systems |  | Adobe Systems |
| 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 |
| January 12, 2008 |  | February 24, 2008 |
| HTTP/1.1, part 3: Message Payload and Content Negotiation |  | HTTP/1.1, part 3: Message Payload and Content Negotiation |
| draft-ietf-httpbis-p3-payload-01 |  | draft-ietf-httpbis-p3-payload-02 |
| Status of this Memo |  | Status of this Memo |
| By submitting this Internet-Draft, each author represents that any |  | By submitting this Internet-Draft, each author represents that any |
| applicable patent or other IPR claims of which he or she is aware |  | applicable patent or other IPR claims of which he or she is aware |
| have been or will be disclosed, and any of which he or she becomes |  | have been or will be disclosed, and any of which he or she becomes |
| aware will be disclosed, in accordance with Section 6 of BCP 79. |  | aware will be disclosed, in accordance with Section 6 of BCP 79. |
| Internet-Drafts are working documents of the Internet Engineering |  | Internet-Drafts are working documents of the Internet Engineering |
| Task Force (IETF), its areas, and its working groups. Note that |  | Task Force (IETF), its areas, and its working groups. Note that |
| skipping to change at page 1, line 49 |  | skipping to change at page 1, line 49 |
| 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." |
| The list of current Internet-Drafts can be accessed at |  | The list of current Internet-Drafts can be accessed at |
| http://www.ietf.org/ietf/1id-abstracts.txt. |  | http://www.ietf.org/ietf/1id-abstracts.txt. |
| The list of Internet-Draft Shadow Directories can be accessed at |  | The list of Internet-Draft Shadow Directories can be accessed at |
| http://www.ietf.org/shadow.html. |  | http://www.ietf.org/shadow.html. |
| This Internet-Draft will expire on July 15, 2008. |  | This Internet-Draft will expire on August 27, 2008. |
| Copyright Notice |  | Copyright Notice |
| Copyright (C) The IETF Trust (2008). |  | Copyright (C) The IETF Trust (2008). |
| Abstract |  | Abstract |
| The Hypertext Transfer Protocol (HTTP) is an application-level |  | The Hypertext Transfer Protocol (HTTP) is an application-level |
| protocol for distributed, collaborative, hypermedia information |  | protocol for distributed, collaborative, hypermedia 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 |
| skipping to change at page 3, line 9 |  | skipping to change at page 3, line 9 |
| This draft incorporates those issue resolutions that were either |  | This draft incorporates those issue resolutions that were either |
| collected in the original RFC2616 errata list |  | collected in the original RFC2616 errata list |
| (<http://purl.org/NET/http-errata>), or which were agreed upon on the |  | (<http://purl.org/NET/http-errata>), or which were agreed upon on the |
| mailing list between October 2006 and November 2007 (as published in |  | mailing list between October 2006 and November 2007 (as published in |
| "draft-lafon-rfc2616bis-03"). |  | "draft-lafon-rfc2616bis-03"). |
| Table of Contents |  | Table of Contents |
| 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 |  | 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 |
| 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 5 |  | 1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 5 |
| 2. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 5 |  | 2. Notational Conventions and Generic Grammar . . . . . . . . . . 5 |
| 2.1. Character Sets . . . . . . . . . . . . . . . . . . . . . . 5 |  | 3. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 6 |
| 2.1.1. Missing Charset . . . . . . . . . . . . . . . . . . . 6 |  | 3.1. Character Sets . . . . . . . . . . . . . . . . . . . . . . 6 |
| 2.2. Content Codings . . . . . . . . . . . . . . . . . . . . . 7 |  | 3.1.1. Missing Charset . . . . . . . . . . . . . . . . . . . 7 |
| 2.3. Media Types . . . . . . . . . . . . . . . . . . . . . . . 8 |  | 3.2. Content Codings . . . . . . . . . . . . . . . . . . . . . 7 |
| 2.3.1. Canonicalization and Text Defaults . . . . . . . . . . 9 |  | 3.3. Media Types . . . . . . . . . . . . . . . . . . . . . . . 9 |
| 2.3.2. Multipart Types . . . . . . . . . . . . . . . . . . . 9 |  | 3.3.1. Canonicalization and Text Defaults . . . . . . . . . . 9 |
| 2.4. Quality Values . . . . . . . . . . . . . . . . . . . . . . 10 |  | 3.3.2. Multipart Types . . . . . . . . . . . . . . . . . . . 10 |
| 2.5. Language Tags . . . . . . . . . . . . . . . . . . . . . . 10 |  | 3.4. Quality Values . . . . . . . . . . . . . . . . . . . . . . 11 |
| 3. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 |  | 3.5. Language Tags . . . . . . . . . . . . . . . . . . . . . . 11 |
| 3.1. Entity Header Fields . . . . . . . . . . . . . . . . . . . 11 |  | 4. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 |
| 3.2. Entity Body . . . . . . . . . . . . . . . . . . . . . . . 12 |  | 4.1. Entity Header Fields . . . . . . . . . . . . . . . . . . . 12 |
| 3.2.1. Type . . . . . . . . . . . . . . . . . . . . . . . . . 12 |  | 4.2. Entity Body . . . . . . . . . . . . . . . . . . . . . . . 12 |
| 3.2.2. Entity Length . . . . . . . . . . . . . . . . . . . . 12 |  | 4.2.1. Type . . . . . . . . . . . . . . . . . . . . . . . . . 13 |
| 4. Content Negotiation . . . . . . . . . . . . . . . . . . . . . 13 |  | 4.2.2. Entity Length . . . . . . . . . . . . . . . . . . . . 13 |
| 4.1. Server-driven Negotiation . . . . . . . . . . . . . . . . 13 |  | 5. Content Negotiation . . . . . . . . . . . . . . . . . . . . . 13 |
| 4.2. Agent-driven Negotiation . . . . . . . . . . . . . . . . . 14 |  | 5.1. Server-driven Negotiation . . . . . . . . . . . . . . . . 14 |
| 4.3. Transparent Negotiation . . . . . . . . . . . . . . . . . 15 |  | 5.2. Agent-driven Negotiation . . . . . . . . . . . . . . . . . 15 |
| 5. Header Field Definitions . . . . . . . . . . . . . . . . . . . 15 |  | 5.3. Transparent Negotiation . . . . . . . . . . . . . . . . . 16 |
| 5.1. Accept . . . . . . . . . . . . . . . . . . . . . . . . . . 16 |  | 6. Header Field Definitions . . . . . . . . . . . . . . . . . . . 16 |
| 5.2. Accept-Charset . . . . . . . . . . . . . . . . . . . . . . 18 |  | 6.1. Accept . . . . . . . . . . . . . . . . . . . . . . . . . . 16 |
| 5.3. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 18 |  | 6.2. Accept-Charset . . . . . . . . . . . . . . . . . . . . . . 18 |
| 5.4. Accept-Language . . . . . . . . . . . . . . . . . . . . . 20 |  | 6.3. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 19 |
| 5.5. Content-Encoding . . . . . . . . . . . . . . . . . . . . . 21 |  | 6.4. Accept-Language . . . . . . . . . . . . . . . . . . . . . 20 |
| 5.6. Content-Language . . . . . . . . . . . . . . . . . . . . . 22 |  | 6.5. Content-Encoding . . . . . . . . . . . . . . . . . . . . . 22 |
| 5.7. Content-Location . . . . . . . . . . . . . . . . . . . . . 22 |  | 6.6. Content-Language . . . . . . . . . . . . . . . . . . . . . 22 |
| 5.8. Content-MD5 . . . . . . . . . . . . . . . . . . . . . . . 23 |  | 6.7. Content-Location . . . . . . . . . . . . . . . . . . . . . 23 |
| 5.9. Content-Type . . . . . . . . . . . . . . . . . . . . . . . 24 |  | 6.8. Content-MD5 . . . . . . . . . . . . . . . . . . . . . . . 24 |
| 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 |  | 6.9. Content-Type . . . . . . . . . . . . . . . . . . . . . . . 25 |
| 7. Security Considerations . . . . . . . . . . . . . . . . . . . 25 |  | 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 |
| 7.1. Privacy Issues Connected to Accept Headers . . . . . . . . 25 |  | 8. Security Considerations . . . . . . . . . . . . . . . . . . . 26 |
| 7.2. Content-Disposition Issues . . . . . . . . . . . . . . . . 26 |  | 8.1. Privacy Issues Connected to Accept Headers . . . . . . . . 26 |
| 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 |  | 8.2. Content-Disposition Issues . . . . . . . . . . . . . . . . 27 |
| 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26 |  | 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 |
| 9.1. Normative References . . . . . . . . . . . . . . . . . . . 26 |  | 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 |
| 9.2. Informative References . . . . . . . . . . . . . . . . . . 28 |  | 10.1. Normative References . . . . . . . . . . . . . . . . . . . 27 |
|  |  | 10.2. Informative References . . . . . . . . . . . . . . . . . . 29 |
| Appendix A. Differences Between HTTP Entities and RFC 2045 |  | Appendix A. Differences Between HTTP Entities and RFC 2045 |
| Entities . . . . . . . . . . . . . . . . . . . . . . 29 |  | Entities . . . . . . . . . . . . . . . . . . . . . . 30 |
| A.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . . 29 |  | A.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . . 30 |
| A.2. Conversion to Canonical Form . . . . . . . . . . . . . . . 30 |  | A.2. Conversion to Canonical Form . . . . . . . . . . . . . . . 30 |
| A.3. Introduction of Content-Encoding . . . . . . . . . . . . . 30 |  | A.3. Introduction of Content-Encoding . . . . . . . . . . . . . 31 |
| A.4. No Content-Transfer-Encoding . . . . . . . . . . . . . . . 30 |  | A.4. No Content-Transfer-Encoding . . . . . . . . . . . . . . . 31 |
| A.5. Introduction of Transfer-Encoding . . . . . . . . . . . . 31 |  | A.5. Introduction of Transfer-Encoding . . . . . . . . . . . . 31 |
| A.6. MHTML and Line Length Limitations . . . . . . . . . . . . 31 |  | A.6. MHTML and Line Length Limitations . . . . . . . . . . . . 32 |
| Appendix B. Additional Features . . . . . . . . . . . . . . . . . 31 |  | Appendix B. Additional Features . . . . . . . . . . . . . . . . . 32 |
| B.1. Content-Disposition . . . . . . . . . . . . . . . . . . . 31 |  | B.1. Content-Disposition . . . . . . . . . . . . . . . . . . . 32 |
| Appendix C. Compatibility with Previous Versions . . . . . . . . 32 |  | Appendix C. Compatibility with Previous Versions . . . . . . . . 33 |
| C.1. Changes from RFC 2068 . . . . . . . . . . . . . . . . . . 32 |  | C.1. Changes from RFC 2068 . . . . . . . . . . . . . . . . . . 33 |
| C.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 33 |  | C.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 33 |
| Appendix D. Change Log (to be removed by RFC Editor before |  | Appendix D. Change Log (to be removed by RFC Editor before |
| publication) . . . . . . . . . . . . . . . . . . . . 33 |  | publication) . . . . . . . . . . . . . . . . . . . . 34 |
| D.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . . 33 |  | D.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . . 34 |
| D.2. Since draft-ietf-httpbis-p3-payload-00 . . . . . . . . . . 33 |  | D.2. Since draft-ietf-httpbis-p3-payload-00 . . . . . . . . . . 34 |
| Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 |  | D.3. Since draft-ietf-httpbis-p3-payload-01 . . . . . . . . . . 35 |
| Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36 |  | Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 |
| Intellectual Property and Copyright Statements . . . . . . . . . . 39 |  | Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37 |
|  |  | Intellectual Property and Copyright Statements . . . . . . . . . . 40 |
| 1. Introduction |  | 1. Introduction |
| This document defines HTTP/1.1 message payloads (a.k.a., content), |  | This document defines HTTP/1.1 message payloads (a.k.a., content), |
| the associated metadata header fields that define how the payload is |  | the associated metadata header fields that define how the payload is |
| intended to be interpreted by a recipient, the request header fields |  | intended to be interpreted by a recipient, the request header fields |
| that may influence content selection, and the various selection |  | that may influence content selection, and the various selection |
| algorithms that are collectively referred to as HTTP content |  | algorithms that are collectively referred to as HTTP content |
| negotiation. |  | negotiation. |
| skipping to change at page 5, line 39 |  | skipping to change at page 5, line 39 |
| An implementation is not compliant if it fails to satisfy one or more |  | An implementation is not compliant if it fails to satisfy one or more |
| of the MUST or REQUIRED level requirements for the protocols it |  | of the MUST or REQUIRED level requirements for the protocols it |
| implements. An implementation that satisfies all the MUST or |  | implements. An implementation that satisfies all the MUST or |
| REQUIRED level and all the SHOULD level requirements for its |  | REQUIRED level and all the SHOULD level requirements for its |
| protocols is said to be "unconditionally compliant"; one that |  | protocols is said to be "unconditionally compliant"; one that |
| satisfies all the MUST level requirements but not all the SHOULD |  | satisfies all the MUST level requirements but not all the SHOULD |
| level requirements for its protocols is said to be "conditionally |  | level requirements for its protocols is said to be "conditionally |
| compliant." |  | compliant." |
| 2. Protocol Parameters |  | 2. Notational Conventions and Generic Grammar |
| 2.1. Character Sets |  | This specification uses the ABNF syntax defined in Section 2.1 of |
|  |  | [Part1] and the core rules defined in Section 2.2 of [Part1]: |
|  |  | [[abnf.dep: ABNF syntax and basic rules will be adopted from RFC |
|  |  | 5234, see <http://tools.ietf.org/wg/httpbis/trac/ticket/36>.]] |
|  |  | ALPHA = <ALPHA, defined in [Part1], Section 2.2> |
|  |  | DIGIT = <DIGIT, defined in [Part1], Section 2.2> |
|  |  | OCTET = <OCTET, defined in [Part1], Section 2.2> |
|  |  | quoted-string = <quoted-string, defined in [Part1], Section 2.2> |
|  |  | token = <token, defined in [Part1], Section 2.2> |
|  |  | The ABNF rules below are defined in other parts: |
|  |  | absoluteURI = <absoluteURI, defined in [Part1], Section 3.2.1> |
|  |  | Content-Length = <Content-Length, defined in [Part1], Section 8.2> |
|  |  | relativeURI = <relativeURI, defined in [Part1], Section 3.2.1> |
|  |  | message-header = <message-header, defined in [Part1], Section 4.2> |
|  |  | Allow = <Allow, defined in [Part2], Section 10.1> |
|  |  | Last-Modified = <Last-Modified, defined in [Part4], Section 7.6> |
|  |  | Content-Range = <Content-Range, defined in [Part5], Section 6.2> |
|  |  | Expires = <Expires, defined in [Part6], Section 16.3> |
|  |  | 3. Protocol Parameters |
|  |  | 3.1. Character Sets |
| HTTP uses the same definition of the term "character set" as that |  | HTTP uses the same definition of the term "character set" as that |
| described for MIME: |  | described for MIME: |
| The term "character set" is used in this document to refer to a |  | The term "character set" is used in this document to refer to a |
| method used with one or more tables to convert a sequence of octets |  | method used with one or more tables to convert a sequence of octets |
| into a sequence of characters. Note that unconditional conversion in |  | into a sequence of characters. Note that unconditional conversion in |
| the other direction is not required, in that not all characters may |  | the other direction is not required, in that not all characters may |
| be available in a given character set and a character set may provide |  | be available in a given character set and a character set may provide |
| more than one sequence of octets to represent a particular character. |  | more than one sequence of octets to represent a particular character. |
| skipping to change at page 6, line 39 |  | skipping to change at page 7, line 26 |
| HTTP uses charset in two contexts: within an Accept-Charset request |  | HTTP uses charset in two contexts: within an Accept-Charset request |
| header (in which the charset value is an unquoted token) and as the |  | header (in which the charset value is an unquoted token) and as the |
| value of a parameter in a Content-Type header (within a request or |  | value of a parameter in a Content-Type header (within a request or |
| response), in which case the parameter value of the charset parameter |  | response), in which case the parameter value of the charset parameter |
| may be quoted. |  | may be quoted. |
| Implementors should be aware of IETF character set requirements |  | Implementors should be aware of IETF character set requirements |
| [RFC3629] [RFC2277]. |  | [RFC3629] [RFC2277]. |
| 2.1.1. Missing Charset |  | 3.1.1. Missing Charset |
| Some HTTP/1.0 software has interpreted a Content-Type header without |  | Some HTTP/1.0 software has interpreted a Content-Type header without |
| charset parameter incorrectly to mean "recipient should guess." |  | charset parameter incorrectly to mean "recipient should guess." |
| Senders wishing to defeat this behavior MAY include a charset |  | Senders wishing to defeat this behavior MAY include a charset |
| parameter even when the charset is ISO-8859-1 ([ISO-8859-1]) and |  | parameter even when the charset is ISO-8859-1 ([ISO-8859-1]) and |
| SHOULD do so when it is known that it will not confuse the recipient. |  | SHOULD do so when it is known that it will not confuse the recipient. |
| Unfortunately, some older HTTP/1.0 clients did not deal properly with |  | Unfortunately, some older HTTP/1.0 clients did not deal properly with |
| an explicit charset parameter. HTTP/1.1 recipients MUST respect the |  | an explicit charset parameter. HTTP/1.1 recipients MUST respect the |
| charset label provided by the sender; and those user agents that have |  | charset label provided by the sender; and those user agents that have |
| a provision to "guess" a charset MUST use the charset from the |  | a provision to "guess" a charset MUST use the charset from the |
| content-type field if they support that charset, rather than the |  | content-type field if they support that charset, rather than the |
| recipient's preference, when initially displaying a document. See |  | recipient's preference, when initially displaying a document. See |
| Section 2.3.1. |  | Section 3.3.1. |
| 2.2. Content Codings |  | 3.2. Content Codings |
| Content coding values indicate an encoding transformation that has |  | Content coding values indicate an encoding transformation that has |
| been or can be applied to an entity. Content codings are primarily |  | been or can be applied to an entity. Content codings are primarily |
| used to allow a document to be compressed or otherwise usefully |  | used to allow a document to be compressed or otherwise usefully |
| transformed without losing the identity of its underlying media type |  | transformed without losing the identity of its underlying media type |
| and without loss of information. Frequently, the entity is stored in |  | and without loss of information. Frequently, the entity is stored in |
| coded form, transmitted directly, and only decoded by the recipient. |  | coded form, transmitted directly, and only decoded by the recipient. |
| content-coding = token |  | content-coding = token |
| All content-coding values are case-insensitive. HTTP/1.1 uses |  | All content-coding values are case-insensitive. HTTP/1.1 uses |
| content-coding values in the Accept-Encoding (Section 5.3) and |  | content-coding values in the Accept-Encoding (Section 6.3) and |
| Content-Encoding (Section 5.5) header fields. Although the value |  | Content-Encoding (Section 6.5) header fields. Although the value |
| describes the content-coding, what is more important is that it |  | describes the content-coding, what is more important is that it |
| indicates what decoding mechanism will be required to remove the |  | indicates what decoding mechanism will be required to remove the |
| encoding. |  | encoding. |
| The Internet Assigned Numbers Authority (IANA) acts as a registry for |  | The Internet Assigned Numbers Authority (IANA) acts as a registry for |
| content-coding value tokens. Initially, the registry contains the |  | content-coding value tokens. Initially, the registry contains the |
| following tokens: |  | following tokens: |
| gzip |  | gzip |
| skipping to change at page 8, line 18 |  | skipping to change at page 9, line 5 |
| whatsoever. This content-coding is used only in the Accept- |  | whatsoever. This content-coding is used only in the Accept- |
| Encoding header, and SHOULD NOT be used in the Content-Encoding |  | Encoding header, and SHOULD NOT be used in the Content-Encoding |
| header. |  | header. |
| New content-coding value tokens SHOULD be registered; to allow |  | New content-coding value tokens SHOULD be registered; to allow |
| interoperability between clients and servers, specifications of the |  | interoperability between clients and servers, specifications of the |
| content coding algorithms needed to implement a new value SHOULD be |  | content coding algorithms needed to implement a new value SHOULD be |
| publicly available and adequate for independent implementation, and |  | publicly available and adequate for independent implementation, and |
| conform to the purpose of content coding defined in this section. |  | conform to the purpose of content coding defined in this section. |
| 2.3. Media Types |  | 3.3. Media Types |
| HTTP uses Internet Media Types [RFC2046] in the Content-Type |  | HTTP uses Internet Media Types [RFC2046] in the Content-Type |
| (Section 5.9) and Accept (Section 5.1) header fields in order to |  | (Section 6.9) and Accept (Section 6.1) header fields in order to |
| provide open and extensible data typing and type negotiation. |  | provide open and extensible data typing and type negotiation. |
| media-type = type "/" subtype *( ";" parameter ) |  | media-type = type "/" subtype *( ";" parameter ) |
| type = token |  | type = token |
| subtype = token |  | subtype = token |
| Parameters MAY follow the type/subtype in the form of attribute/value |  | Parameters MAY follow the type/subtype in the form of attribute/value |
| pairs. |  | pairs. |
| parameter = attribute "=" value |  | parameter = attribute "=" value |
| skipping to change at page 9, line 5 |  | skipping to change at page 9, line 39 |
| Note that some older HTTP applications do not recognize media type |  | Note that some older HTTP applications do not recognize media type |
| parameters. When sending data to older HTTP applications, |  | parameters. When sending data to older HTTP applications, |
| implementations SHOULD only use media type parameters when they are |  | implementations SHOULD only use media type parameters when they are |
| required by that type/subtype definition. |  | required by that type/subtype definition. |
| Media-type values are registered with the Internet Assigned Number |  | Media-type values are registered with the Internet Assigned Number |
| Authority (IANA). The media type registration process is outlined in |  | Authority (IANA). The media type registration process is outlined in |
| [RFC4288]. Use of non-registered media types is discouraged. |  | [RFC4288]. Use of non-registered media types is discouraged. |
| 2.3.1. Canonicalization and Text Defaults |  | 3.3.1. Canonicalization and Text Defaults |
| Internet media types are registered with a canonical form. An |  | Internet media types are registered with a canonical form. An |
| entity-body transferred via HTTP messages MUST be represented in the |  | entity-body transferred via HTTP messages MUST be represented in the |
| appropriate canonical form prior to its transmission except for |  | appropriate canonical form prior to its transmission except for |
| "text" types, as defined in the next paragraph. |  | "text" types, as defined in the next paragraph. |
| When in canonical form, media subtypes of the "text" type use CRLF as |  | When in canonical form, media subtypes of the "text" type use CRLF as |
| the text line break. HTTP relaxes this requirement and allows the |  | the text line break. HTTP relaxes this requirement and allows the |
| transport of text media with plain CR or LF alone representing a line |  | transport of text media with plain CR or LF alone representing a line |
| break when it is done consistently for an entire entity-body. HTTP |  | break when it is done consistently for an entire entity-body. HTTP |
| skipping to change at page 9, line 31 |  | skipping to change at page 10, line 16 |
| sequences are defined by that character set to represent the |  | sequences are defined by that character set to represent the |
| equivalent of CR and LF for line breaks. This flexibility regarding |  | equivalent of CR and LF for line breaks. This flexibility regarding |
| line breaks applies only to text media in the entity-body; a bare CR |  | line breaks applies only to text media in the entity-body; a bare CR |
| or LF MUST NOT be substituted for CRLF within any of the HTTP control |  | or LF MUST NOT be substituted for CRLF within any of the HTTP control |
| structures (such as header fields and multipart boundaries). |  | structures (such as header fields and multipart boundaries). |
| If an entity-body is encoded with a content-coding, the underlying |  | If an entity-body is encoded with a content-coding, the underlying |
| data MUST be in a form defined above prior to being encoded. |  | data MUST be in a form defined above prior to being encoded. |
| The "charset" parameter is used with some media types to define the |  | The "charset" parameter is used with some media types to define the |
| character set (Section 2.1) of the data. When no explicit charset |  | character set (Section 3.1) of the data. When no explicit charset |
| parameter is provided by the sender, media subtypes of the "text" |  | parameter is provided by the sender, media subtypes of the "text" |
| type are defined to have a default charset value of "ISO-8859-1" when |  | type are defined to have a default charset value of "ISO-8859-1" when |
| received via HTTP. Data in character sets other than "ISO-8859-1" or |  | received via HTTP. Data in character sets other than "ISO-8859-1" or |
| its subsets MUST be labeled with an appropriate charset value. See |  | its subsets MUST be labeled with an appropriate charset value. See |
| Section 2.1.1 for compatibility problems. |  | Section 3.1.1 for compatibility problems. |
| 2.3.2. Multipart Types |  | 3.3.2. Multipart Types |
| MIME provides for a number of "multipart" types -- encapsulations of |  | MIME provides for a number of "multipart" types -- encapsulations of |
| one or more entities within a single message-body. All multipart |  | one or more entities within a single message-body. All multipart |
| types share a common syntax, as defined in Section 5.1.1 of |  | types share a common syntax, as defined in Section 5.1.1 of |
| [RFC2046], and MUST include a boundary parameter as part of the media |  | [RFC2046], and MUST include a boundary parameter as part of the media |
| type value. The message body is itself a protocol element and MUST |  | type value. The message body is itself a protocol element and MUST |
| therefore use only CRLF to represent line breaks between body-parts. |  | therefore use only CRLF to represent line breaks between body-parts. |
| Unlike in RFC 2046, the epilogue of any multipart message MUST be |  | Unlike in RFC 2046, the epilogue of any multipart message MUST be |
| empty; HTTP applications MUST NOT transmit the epilogue (even if the |  | empty; HTTP applications MUST NOT transmit the epilogue (even if the |
| original multipart contains an epilogue). These restrictions exist |  | original multipart contains an epilogue). These restrictions exist |
| skipping to change at page 10, line 23 |  | skipping to change at page 11, line 9 |
| In general, an HTTP user agent SHOULD follow the same or similar |  | In general, an HTTP user agent SHOULD follow the same or similar |
| behavior as a MIME user agent would upon receipt of a multipart type. |  | behavior as a MIME user agent would upon receipt of a multipart type. |
| If an application receives an unrecognized multipart subtype, the |  | If an application receives an unrecognized multipart subtype, the |
| application MUST treat it as being equivalent to "multipart/mixed". |  | application MUST treat it as being equivalent to "multipart/mixed". |
| Note: The "multipart/form-data" type has been specifically defined |  | Note: The "multipart/form-data" type has been specifically defined |
| for carrying form data suitable for processing via the POST |  | for carrying form data suitable for processing via the POST |
| request method, as described in [RFC2388]. |  | request method, as described in [RFC2388]. |
| 2.4. Quality Values |  | 3.4. Quality Values |
| HTTP content negotiation (Section 4) uses short "floating point" |  | HTTP content negotiation (Section 5) uses 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") ] ) |
| "Quality values" is a misnomer, since these values merely represent |  | "Quality values" is a misnomer, since these values merely represent |
| relative degradation in desired quality. |  | relative degradation in desired quality. |
| 2.5. Language Tags |  | 3.5. Language Tags |
| A language tag identifies a natural language spoken, written, or |  | A language tag identifies a natural language spoken, written, or |
| otherwise conveyed by human beings for communication of information |  | otherwise conveyed by human beings for communication of information |
| to other human beings. Computer languages are explicitly excluded. |  | to other human beings. Computer languages are explicitly excluded. |
| HTTP uses language tags within the Accept-Language and Content- |  | HTTP uses language tags within the Accept-Language and Content- |
| Language fields. |  | Language fields. |
| The syntax and registry of HTTP language tags is the same as that |  | The syntax and registry of HTTP language tags is the same as that |
| defined by [RFC1766]. In summary, a language tag is composed of 1 or |  | defined by [RFC1766]. In summary, a language tag is composed of 1 or |
| more parts: A primary language tag and a possibly empty series of |  | more parts: A primary language tag and a possibly empty series of |
| skipping to change at page 11, line 20 |  | skipping to change at page 12, line 6 |
| insensitive. The name space of language tags is administered by the |  | insensitive. The name space of language tags is administered by the |
| IANA. Example tags include: |  | IANA. Example tags include: |
| en, en-US, en-cockney, i-cherokee, x-pig-latin |  | en, en-US, en-cockney, i-cherokee, x-pig-latin |
| where any two-letter primary-tag is an ISO-639 language abbreviation |  | where any two-letter primary-tag is an ISO-639 language abbreviation |
| and any two-letter initial subtag is an ISO-3166 country code. (The |  | and any two-letter initial subtag is an ISO-3166 country code. (The |
| last three tags above are not registered tags; all but the last are |  | last three tags above are not registered tags; all but the last are |
| examples of tags which could be registered in future.) |  | examples of tags which could be registered in future.) |
| 3. Entity |  | 4. Entity |
| Request and Response messages MAY transfer an entity if not otherwise |  | Request and Response messages MAY transfer an entity if not otherwise |
| restricted by the request method or response status code. An entity |  | restricted by the request method or response status code. An entity |
| consists of entity-header fields and an entity-body, although some |  | consists of entity-header fields and an entity-body, although some |
| responses will only include the entity-headers. |  | responses will only include the entity-headers. |
| In this section, both sender and recipient refer to either the client |  | In this section, both sender and recipient refer to either the client |
| or the server, depending on who sends and who receives the entity. |  | or the server, depending on who sends and who receives the entity. |
| 3.1. Entity Header Fields |  | 4.1. Entity Header Fields |
| Entity-header fields define metainformation about the entity-body or, |  | Entity-header fields define metainformation about the entity-body or, |
| if no body is present, about the resource identified by the request. |  | if no body is present, about the resource identified by the request. |
| entity-header = Allow ; [Part2], Section 10.1 |  | entity-header = Allow ; [Part2], Section 10.1 |
| | Content-Encoding ; Section 5.5 |  | | Content-Encoding ; Section 6.5 |
| | Content-Language ; Section 5.6 |  | | Content-Language ; Section 6.6 |
| | Content-Length ; [Part1], Section 8.2 |  | | Content-Length ; [Part1], Section 8.2 |
| | Content-Location ; Section 5.7 |  | | Content-Location ; Section 6.7 |
| | Content-MD5 ; Section 5.8 |  | | Content-MD5 ; Section 6.8 |
| | Content-Range ; [Part5], Section 5.2 |  | | Content-Range ; [Part5], Section 6.2 |
| | Content-Type ; Section 5.9 |  | | Content-Type ; Section 6.9 |
| | Expires ; [Part6], Section 15.3 |  | | Expires ; [Part6], Section 16.3 |
| | Last-Modified ; [Part4], Section 6.6 |  | | Last-Modified ; [Part4], Section 7.6 |
| | extension-header |  | | extension-header |
| extension-header = message-header |  | extension-header = message-header |
| The extension-header mechanism allows additional entity-header fields |  | The extension-header mechanism allows additional entity-header fields |
| to be defined without changing the protocol, but these fields cannot |  | to be defined without changing the protocol, but these fields cannot |
| be assumed to be recognizable by the recipient. Unrecognized header |  | be assumed to be recognizable by the recipient. Unrecognized header |
| fields SHOULD be ignored by the recipient and MUST be forwarded by |  | fields SHOULD be ignored by the recipient and MUST be forwarded by |
| transparent proxies. |  | transparent proxies. |
| 3.2. Entity Body |  | 4.2. Entity Body |
| The entity-body (if any) sent with an HTTP request or response is in |  | The entity-body (if any) sent with an HTTP request or response is in |
| a format and encoding defined by the entity-header fields. |  | a format and encoding defined by the entity-header fields. |
| entity-body = *OCTET |  | entity-body = *OCTET |
| An entity-body is only present in a message when a message-body is |  | An entity-body is only present in a message when a message-body is |
| present, as described in Section 4.3 of [Part1]. The entity-body is |  | present, as described in Section 4.3 of [Part1]. The entity-body is |
| obtained from the message-body by decoding any Transfer-Encoding that |  | obtained from the message-body by decoding any Transfer-Encoding that |
| might have been applied to ensure safe and proper transfer of the |  | might have been applied to ensure safe and proper transfer of the |
| message. |  | message. |
| 3.2.1. Type |  | 4.2.1. Type |
| When an entity-body is included with a message, the data type of that |  | When an entity-body is included with a message, the data type of that |
| body is determined via the header fields Content-Type and Content- |  | body is determined via the header fields Content-Type and Content- |
| Encoding. These define a two-layer, ordered encoding model: |  | Encoding. These define a two-layer, ordered encoding model: |
| entity-body := Content-Encoding( Content-Type( data ) ) |  | entity-body := Content-Encoding( Content-Type( data ) ) |
| Content-Type specifies the media type of the underlying data. |  | Content-Type specifies the media type of the underlying data. |
| Content-Encoding may be used to indicate any additional content |  | Content-Encoding may be used to indicate any additional content |
| codings applied to the data, usually for the purpose of data |  | codings applied to the data, usually for the purpose of data |
| skipping to change at page 12, line 42 |  | skipping to change at page 13, line 29 |
| no default encoding. |  | no default encoding. |
| Any HTTP/1.1 message containing an entity-body SHOULD include a |  | Any HTTP/1.1 message containing an entity-body SHOULD include a |
| Content-Type header field defining the media type of that body. If |  | Content-Type header field defining the media type of that body. If |
| and only if the media type is not given by a Content-Type field, the |  | and only if the media type is not given by a Content-Type field, the |
| recipient MAY attempt to guess the media type via inspection of its |  | recipient MAY attempt to guess the media type via inspection of its |
| content and/or the name extension(s) of the URI used to identify the |  | content and/or the name extension(s) of the URI used to identify the |
| resource. If the media type remains unknown, the recipient SHOULD |  | resource. If the media type remains unknown, the recipient SHOULD |
| treat it as type "application/octet-stream". |  | treat it as type "application/octet-stream". |
| 3.2.2. Entity Length |  | 4.2.2. Entity Length |
| The entity-length of a message is the length of the message-body |  | The entity-length of a message is the length of the message-body |
| before any transfer-codings have been applied. Section 4.4 of |  | before any transfer-codings have been applied. Section 4.4 of |
| [Part1] defines how the transfer-length of a message-body is |  | [Part1] defines how the transfer-length of a message-body is |
| determined. |  | determined. |
| 4. Content Negotiation |  | 5. Content Negotiation |
| Most HTTP responses include an entity which contains information for |  | Most HTTP responses include an entity which contains information for |
| interpretation by a human user. Naturally, it is desirable to supply |  | interpretation by a human user. Naturally, it is desirable to supply |
| the user with the "best available" entity corresponding to the |  | the user with the "best available" entity corresponding to the |
| request. Unfortunately for servers and caches, not all users have |  | request. Unfortunately for servers and caches, not all users have |
| the same preferences for what is "best," and not all user agents are |  | the same preferences for what is "best," and not all user agents are |
| equally capable of rendering all entity types. For that reason, HTTP |  | equally capable of rendering all entity types. For that reason, HTTP |
| has provisions for several mechanisms for "content negotiation" -- |  | has provisions for several mechanisms for "content negotiation" -- |
| the process of selecting the best representation for a given response |  | the process of selecting the best representation for a given response |
| when there are multiple representations available. |  | when there are multiple representations available. |
| skipping to change at page 13, line 33 |  | skipping to change at page 14, line 17 |
| including error responses. |  | including error responses. |
| There are two kinds of content negotiation which are possible in |  | There are two kinds of content negotiation which are possible in |
| HTTP: server-driven and agent-driven negotiation. These two kinds of |  | HTTP: server-driven and agent-driven negotiation. These two kinds of |
| negotiation are orthogonal and thus may be used separately or in |  | negotiation are orthogonal and thus may be used separately or in |
| combination. One method of combination, referred to as transparent |  | combination. One method of combination, referred to as transparent |
| negotiation, occurs when a cache uses the agent-driven negotiation |  | negotiation, occurs when a cache uses the agent-driven negotiation |
| information provided by the origin server in order to provide server- |  | information provided by the origin server in order to provide server- |
| driven negotiation for subsequent requests. |  | driven negotiation for subsequent requests. |
| 4.1. Server-driven Negotiation |  | 5.1. Server-driven Negotiation |
| If the selection of the best representation for a response is made by |  | If the selection of the best representation for a response is made by |
| an algorithm located at the server, it is called server-driven |  | an algorithm located at the server, it is called server-driven |
| negotiation. Selection is based on the available representations of |  | negotiation. Selection is based on the available representations of |
| the response (the dimensions over which it can vary; e.g. language, |  | the response (the dimensions over which it can vary; e.g. language, |
| content-coding, etc.) and the contents of particular header fields in |  | content-coding, etc.) and the contents of particular header fields in |
| the request message or on other information pertaining to the request |  | the request message or on other information pertaining to the request |
| (such as the network address of the client). |  | (such as the network address of the client). |
| Server-driven negotiation is advantageous when the algorithm for |  | Server-driven negotiation is advantageous when the algorithm for |
| skipping to change at page 14, line 26 |  | skipping to change at page 15, line 10 |
| violation of the user's privacy. |  | violation of the user's privacy. |
| 3. It complicates the implementation of an origin server and the |  | 3. It complicates the implementation of an origin server and the |
| algorithms for generating responses to a request. |  | algorithms for generating responses to a request. |
| 4. It may limit a public cache's ability to use the same response |  | 4. It may limit a public cache's ability to use the same response |
| for multiple user's requests. |  | for multiple user's requests. |
| HTTP/1.1 includes the following request-header fields for enabling |  | HTTP/1.1 includes the following request-header fields for enabling |
| server-driven negotiation through description of user agent |  | server-driven negotiation through description of user agent |
| capabilities and user preferences: Accept (Section 5.1), Accept- |  | capabilities and user preferences: Accept (Section 6.1), Accept- |
| Charset (Section 5.2), Accept-Encoding (Section 5.3), Accept-Language |  | Charset (Section 6.2), Accept-Encoding (Section 6.3), Accept-Language |
| (Section 5.4), and User-Agent (Section 10.9 of [Part2]). However, an |  | (Section 6.4), and User-Agent (Section 10.9 of [Part2]). However, an |
| origin server is not limited to these dimensions and MAY vary the |  | origin server is not limited to these dimensions and MAY vary the |
| response based on any aspect of the request, including information |  | response based on any aspect of the request, including information |
| outside the request-header fields or within extension header fields |  | outside the request-header fields or within extension header fields |
| not defined by this specification. |  | not defined by this specification. |
| The Vary header field (Section 15.5 of [Part6]) can be used to |  | The Vary header field (Section 16.5 of [Part6]) can be used to |
| express the parameters the server uses to select a representation |  | express the parameters the server uses to select a representation |
| that is subject to server-driven negotiation. |  | that is subject to server-driven negotiation. |
| 4.2. Agent-driven Negotiation |  | 5.2. Agent-driven Negotiation |
| With agent-driven negotiation, selection of the best representation |  | With agent-driven negotiation, selection of the best representation |
| for a response is performed by the user agent after receiving an |  | for a response is performed by the user agent after receiving an |
| initial response from the origin server. Selection is based on a |  | initial response from the origin server. Selection is based on a |
| list of the available representations of the response included within |  | list of the available representations of the response included within |
| the header fields or entity-body of the initial response, with each |  | the header fields or entity-body of the initial response, with each |
| representation identified by its own URI. Selection from among the |  | representation identified by its own URI. Selection from among the |
| representations may be performed automatically (if the user agent is |  | representations may be performed automatically (if the user agent is |
| capable of doing so) or manually by the user selecting from a |  | capable of doing so) or manually by the user selecting from a |
| generated (possibly hypertext) menu. |  | generated (possibly hypertext) menu. |
| skipping to change at page 15, line 20 |  | skipping to change at page 16, line 5 |
| this specification does not define any mechanism for supporting |  | this specification does not define any mechanism for supporting |
| automatic selection, though it also does not prevent any such |  | automatic selection, though it also does not prevent any such |
| mechanism from being developed as an extension and used within |  | mechanism from being developed as an extension and used within |
| HTTP/1.1. |  | HTTP/1.1. |
| HTTP/1.1 defines the 300 (Multiple Choices) and 406 (Not Acceptable) |  | HTTP/1.1 defines the 300 (Multiple Choices) and 406 (Not Acceptable) |
| status codes for enabling agent-driven negotiation when the server is |  | status codes for enabling agent-driven negotiation when the server is |
| unwilling or unable to provide a varying response using server-driven |  | unwilling or unable to provide a varying response using server-driven |
| negotiation. |  | negotiation. |
| 4.3. Transparent Negotiation |  | 5.3. Transparent Negotiation |
| Transparent negotiation is a combination of both server-driven and |  | Transparent negotiation is a combination of both server-driven and |
| agent-driven negotiation. When a cache is supplied with a form of |  | agent-driven negotiation. When a cache is supplied with a form of |
| the list of available representations of the response (as in agent- |  | the list of available representations of the response (as in agent- |
| driven negotiation) and the dimensions of variance are completely |  | driven negotiation) and the dimensions of variance are completely |
| understood by the cache, then the cache becomes capable of performing |  | understood by the cache, then the cache becomes capable of performing |
| server-driven negotiation on behalf of the origin server for |  | server-driven negotiation on behalf of the origin server for |
| subsequent requests on that resource. |  | subsequent requests on that resource. |
| Transparent negotiation has the advantage of distributing the |  | Transparent negotiation has the advantage of distributing the |
| negotiation work that would otherwise be required of the origin |  | negotiation work that would otherwise be required of the origin |
| server and also removing the second request delay of agent-driven |  | server and also removing the second request delay of agent-driven |
| negotiation when the cache is able to correctly guess the right |  | negotiation when the cache is able to correctly guess the right |
| response. |  | response. |
| This specification does not define any mechanism for transparent |  | This specification does not define any mechanism for transparent |
| negotiation, though it also does not prevent any such mechanism from |  | negotiation, though it also does not prevent any such mechanism from |
| being developed as an extension that could be used within HTTP/1.1. |  | being developed as an extension that could be used within HTTP/1.1. |
| 5. Header Field Definitions |  | 6. Header Field Definitions |
| This section defines the syntax and semantics of HTTP/1.1 header |  | This section defines the syntax and semantics of HTTP/1.1 header |
| fields related to the payload of messages. |  | fields related to the payload of messages. |
| For entity-header fields, both sender and recipient refer to either |  | For entity-header fields, both sender and recipient refer to either |
| the client or the server, depending on who sends and who receives the |  | the client or the server, depending on who sends and who receives the |
| entity. |  | entity. |
| 5.1. Accept |  | 6.1. Accept |
| The Accept request-header field can be used to specify certain media |  | The Accept request-header field can be used to specify certain media |
| types which are acceptable for the response. Accept headers can be |  | types which are acceptable for the response. Accept headers can be |
| used to indicate that the request is specifically limited to a small |  | used to indicate that the request is specifically limited to a small |
| set of desired types, as in the case of a request for an in-line |  | set of desired types, as in the case of a request for an in-line |
| image. |  | image. |
| Accept = "Accept" ":" |  | Accept = "Accept" ":" |
| #( media-range [ accept-params ] ) |  | #( media-range [ accept-params ] ) |
| skipping to change at page 16, line 33 |  | skipping to change at page 17, line 14 |
| The asterisk "*" character is used to group media types into ranges, |  | The asterisk "*" character is used to group media types into ranges, |
| with "*/*" indicating all media types and "type/*" indicating all |  | with "*/*" indicating all media types and "type/*" indicating all |
| subtypes of that type. The media-range MAY include media type |  | subtypes of that type. The media-range MAY include media type |
| parameters that are applicable to that range. |  | parameters that are applicable to that range. |
| Each media-range MAY be followed by one or more accept-params, |  | Each media-range MAY be followed by one or more accept-params, |
| beginning with the "q" parameter for indicating a relative quality |  | beginning with the "q" parameter for indicating a relative quality |
| factor. The first "q" parameter (if any) separates the media-range |  | factor. The first "q" parameter (if any) separates the media-range |
| parameter(s) from the accept-params. Quality factors allow the user |  | parameter(s) from the accept-params. Quality factors allow the user |
| or user agent to indicate the relative degree of preference for that |  | or user agent to indicate the relative degree of preference for that |
| media-range, using the qvalue scale from 0 to 1 (Section 2.4). The |  | media-range, using the qvalue scale from 0 to 1 (Section 3.4). The |
| default value is q=1. |  | default value is q=1. |
| Note: Use of the "q" parameter name to separate media type |  | Note: Use of the "q" parameter name to separate media type |
| parameters from Accept extension parameters is due to historical |  | parameters from Accept extension parameters is due to historical |
| practice. Although this prevents any media type parameter named |  | practice. Although this prevents any media type parameter named |
| "q" from being used with a media range, such an event is believed |  | "q" from being used with a media range, such an event is believed |
| to be unlikely given the lack of any "q" parameters in the IANA |  | to be unlikely given the lack of any "q" parameters in the IANA |
| media type registry and the rare usage of any media type |  | media type registry and the rare usage of any media type |
| parameters in Accept. Future media types are discouraged from |  | parameters in Accept. Future media types are discouraged from |
| registering any parameter named "q". |  | registering any parameter named "q". |
| skipping to change at page 18, line 5 |  | skipping to change at page 18, line 34 |
| text/plain = 0.3 |  | text/plain = 0.3 |
| image/jpeg = 0.5 |  | image/jpeg = 0.5 |
| text/html;level=2 = 0.4 |  | text/html;level=2 = 0.4 |
| text/html;level=3 = 0.7 |  | text/html;level=3 = 0.7 |
| Note: A user agent might be provided with a default set of quality |  | Note: A user agent might be provided with a default set of quality |
| values for certain media ranges. However, unless the user agent is a |  | values for certain media ranges. However, unless the user agent is a |
| closed system which cannot interact with other rendering agents, this |  | closed system which cannot interact with other rendering agents, this |
| default set ought to be configurable by the user. |  | default set ought to be configurable by the user. |
| 5.2. Accept-Charset |  | 6.2. Accept-Charset |
| The Accept-Charset request-header field can be used to indicate what |  | The Accept-Charset request-header field can be used to indicate what |
| character sets are acceptable for the response. This field allows |  | character sets are acceptable for the response. This field allows |
| clients capable of understanding more comprehensive or special- |  | clients capable of understanding more comprehensive or special- |
| purpose character sets to signal that capability to a server which is |  | purpose character sets to signal that capability to a server which is |
| capable of representing documents in those character sets. |  | capable of representing documents in those character sets. |
| Accept-Charset = "Accept-Charset" ":" |  | Accept-Charset = "Accept-Charset" ":" |
| 1#( ( charset | "*" ) [ ";" "q" "=" qvalue ] ) |  | 1#( ( charset | "*" ) [ ";" "q" "=" qvalue ] ) |
| Character set values are described in Section 2.1. Each charset MAY |  | Character set values are described in Section 3.1. Each charset MAY |
| be given an associated quality value which represents the user's |  | be given an associated quality value which represents the user's |
| preference for that charset. The default value is q=1. An example |  | preference for that charset. The default value is q=1. An example |
| is |  | is |
| Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 |  | Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 |
| The special value "*", if present in the Accept-Charset field, |  | The special value "*", if present in the Accept-Charset field, |
| matches every character set (including ISO-8859-1) which is not |  | matches every character set (including ISO-8859-1) which is not |
| mentioned elsewhere in the Accept-Charset field. If no "*" is |  | mentioned elsewhere in the Accept-Charset field. If no "*" is |
| present in an Accept-Charset field, then all character sets not |  | present in an Accept-Charset field, then all character sets not |
| explicitly mentioned get a quality value of 0, except for ISO-8859-1, |  | explicitly mentioned get a quality value of 0, except for ISO-8859-1, |
| which gets a quality value of 1 if not explicitly mentioned. |  | which gets a quality value of 1 if not explicitly mentioned. |
| If no Accept-Charset header is present, the default is that any |  | If no Accept-Charset header is present, the default is that any |
| character set is acceptable. If an Accept-Charset header is present, |  | character set is acceptable. If an Accept-Charset header is present, |
| and if the server cannot send a response which is acceptable |  | and if the server cannot send a response which is acceptable |
| skipping to change at page 18, line 37 |  | skipping to change at page 19, line 18 |
| explicitly mentioned get a quality value of 0, except for ISO-8859-1, |  | explicitly mentioned get a quality value of 0, except for ISO-8859-1, |
| which gets a quality value of 1 if not explicitly mentioned. |  | which gets a quality value of 1 if not explicitly mentioned. |
| If no Accept-Charset header is present, the default is that any |  | If no Accept-Charset header is present, the default is that any |
| character set is acceptable. If an Accept-Charset header is present, |  | character set is acceptable. If an Accept-Charset header is present, |
| and if the server cannot send a response which is acceptable |  | and if the server cannot send a response which is acceptable |
| according to the Accept-Charset header, then the server SHOULD send |  | according to the Accept-Charset header, then the server SHOULD send |
| an error response with the 406 (Not Acceptable) status code, though |  | an error response with the 406 (Not Acceptable) status code, though |
| the sending of an unacceptable response is also allowed. |  | the sending of an unacceptable response is also allowed. |
| 5.3. Accept-Encoding |  | 6.3. Accept-Encoding |
| The Accept-Encoding request-header field is similar to Accept, but |  | The Accept-Encoding request-header field is similar to Accept, but |
| restricts the content-codings (Section 2.2) that are acceptable in |  | restricts the content-codings (Section 3.2) that are acceptable in |
| the response. |  | the response. |
| Accept-Encoding = "Accept-Encoding" ":" |  | Accept-Encoding = "Accept-Encoding" ":" |
| #( codings [ ";" "q" "=" qvalue ] ) |  | #( codings [ ";" "q" "=" qvalue ] ) |
| codings = ( content-coding | "*" ) |  | codings = ( content-coding | "*" ) |
| Examples of its use are: |  | Examples of its use are: |
| Accept-Encoding: compress, gzip |  | Accept-Encoding: compress, gzip |
| Accept-Encoding: |  | Accept-Encoding: |
| Accept-Encoding: * |  | Accept-Encoding: * |
| Accept-Encoding: compress;q=0.5, gzip;q=1.0 |  | Accept-Encoding: compress;q=0.5, gzip;q=1.0 |
| Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 |  | Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 |
| A server tests whether a content-coding is acceptable, according to |  | A server tests whether a content-coding is acceptable, according to |
| an Accept-Encoding field, using these rules: |  | an Accept-Encoding field, using these rules: |
| 1. If the content-coding is one of the content-codings listed in the |  | 1. If the content-coding is one of the content-codings listed in the |
| Accept-Encoding field, then it is acceptable, unless it is |  | Accept-Encoding field, then it is acceptable, unless it is |
| accompanied by a qvalue of 0. (As defined in Section 2.4, a |  | accompanied by a qvalue of 0. (As defined in Section 3.4, a |
| qvalue of 0 means "not acceptable.") |  | qvalue of 0 means "not acceptable.") |
| 2. The special "*" symbol in an Accept-Encoding field matches any |  | 2. The special "*" symbol in an Accept-Encoding field matches any |
| available content-coding not explicitly listed in the header |  | available content-coding not explicitly listed in the header |
| field. |  | field. |
| 3. If multiple content-codings are acceptable, then the acceptable |  | 3. If multiple content-codings are acceptable, then the acceptable |
| content-coding with the highest non-zero qvalue is preferred. |  | content-coding with the highest non-zero qvalue is preferred. |
| 4. The "identity" content-coding is always acceptable, unless |  | 4. The "identity" content-coding is always acceptable, unless |
| skipping to change at page 20, line 5 |  | skipping to change at page 20, line 36 |
| codings commonly understood by HTTP/1.0 clients (i.e., "gzip" and |  | codings commonly understood by HTTP/1.0 clients (i.e., "gzip" and |
| "compress") are preferred; some older clients improperly display |  | "compress") are preferred; some older clients improperly display |
| messages sent with other content-codings. The server might also |  | messages sent with other content-codings. The server might also |
| make this decision based on information about the particular user- |  | make this decision based on information about the particular user- |
| agent or client. |  | agent or client. |
| Note: Most HTTP/1.0 applications do not recognize or obey qvalues |  | Note: Most HTTP/1.0 applications do not recognize or obey qvalues |
| associated with content-codings. This means that qvalues will not |  | associated with content-codings. This means that qvalues will not |
| work and are not permitted with x-gzip or x-compress. |  | work and are not permitted with x-gzip or x-compress. |
| 5.4. Accept-Language |  | 6.4. Accept-Language |
| The Accept-Language request-header field is similar to Accept, but |  | The Accept-Language request-header field is similar to Accept, but |
| restricts the set of natural languages that are preferred as a |  | restricts the set of natural languages that are preferred as a |
| response to the request. Language tags are defined in Section 2.5. |  | response to the request. Language tags are defined in Section 3.5. |
| Accept-Language = "Accept-Language" ":" |  | Accept-Language = "Accept-Language" ":" |
| 1#( language-range [ ";" "q" "=" qvalue ] ) |  | 1#( language-range [ ";" "q" "=" qvalue ] ) |
| language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" ) |  | language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" ) |
| Each language-range MAY be given an associated quality value which |  | Each language-range MAY be given an associated quality value which |
| represents an estimate of the user's preference for the languages |  | represents an estimate of the user's preference for the languages |
| specified by that range. The quality value defaults to "q=1". For |  | specified by that range. The quality value defaults to "q=1". For |
| example, |  | example, |
| skipping to change at page 20, line 49 |  | skipping to change at page 21, line 31 |
| the field that matches the language-tag. If no language-range in the |  | the field that matches the language-tag. If no language-range in the |
| field matches the tag, the language quality factor assigned is 0. If |  | field matches the tag, the language quality factor assigned is 0. If |
| no Accept-Language header is present in the request, the server |  | no Accept-Language header is present in the request, the server |
| SHOULD assume that all languages are equally acceptable. If an |  | SHOULD assume that all languages are equally acceptable. If an |
| Accept-Language header is present, then all languages which are |  | Accept-Language header is present, then all languages which are |
| assigned a quality factor greater than 0 are acceptable. |  | assigned a quality factor greater than 0 are acceptable. |
| It might be contrary to the privacy expectations of the user to send |  | It might be contrary to the privacy expectations of the user to send |
| an Accept-Language header with the complete linguistic preferences of |  | an Accept-Language header with the complete linguistic preferences of |
| the user in every request. For a discussion of this issue, see |  | the user in every request. For a discussion of this issue, see |
| Section 7.1. |  | Section 8.1. |
| As intelligibility is highly dependent on the individual user, it is |  | As intelligibility is highly dependent on the individual user, it is |
| recommended that client applications make the choice of linguistic |  | recommended that client applications make the choice of linguistic |
| preference available to the user. If the choice is not made |  | preference available to the user. If the choice is not made |
| available, then the Accept-Language header field MUST NOT be given in |  | available, then the Accept-Language header field MUST NOT be given in |
| the request. |  | the request. |
| Note: When making the choice of linguistic preference available to |  | Note: When making the choice of linguistic preference available to |
| the user, we remind implementors of the fact that users are not |  | the user, we remind implementors of the fact that users are not |
| familiar with the details of language matching as described above, |  | familiar with the details of language matching as described above, |
| and should provide appropriate guidance. As an example, users |  | and should provide appropriate guidance. As an example, users |
| might assume that on selecting "en-gb", they will be served any |  | might assume that on selecting "en-gb", they will be served any |
| kind of English document if British English is not available. A |  | kind of English document if British English is not available. A |
| user agent might suggest in such a case to add "en" to get the |  | user agent might suggest in such a case to add "en" to get the |
| best matching behavior. |  | best matching behavior. |
| 5.5. Content-Encoding |  | 6.5. Content-Encoding |
| The Content-Encoding entity-header field is used as a modifier to the |  | The Content-Encoding entity-header field is used as a modifier to the |
| media-type. When present, its value indicates what additional |  | media-type. When present, its value indicates what additional |
| content codings have been applied to the entity-body, and thus what |  | content codings have been applied to the entity-body, and thus what |
| decoding mechanisms must be applied in order to obtain the media-type |  | decoding mechanisms must be applied in order to obtain the media-type |
| referenced by the Content-Type header field. Content-Encoding is |  | referenced by the Content-Type header field. Content-Encoding is |
| primarily used to allow a document to be compressed without losing |  | primarily used to allow a document to be compressed without losing |
| the identity of its underlying media type. |  | the identity of its underlying media type. |
| Content-Encoding = "Content-Encoding" ":" 1#content-coding |  | Content-Encoding = "Content-Encoding" ":" 1#content-coding |
| Content codings are defined in Section 2.2. An example of its use is |  | Content codings are defined in Section 3.2. An example of its use is |
| Content-Encoding: gzip |  | Content-Encoding: gzip |
| The content-coding is a characteristic of the entity identified by |  | The content-coding is a characteristic of the entity identified by |
| the Request-URI. Typically, the entity-body is stored with this |  | the Request-URI. Typically, the entity-body is stored with this |
| encoding and is only decoded before rendering or analogous usage. |  | encoding and is only decoded before rendering or analogous usage. |
| However, a non-transparent proxy MAY modify the content-coding if the |  | However, a non-transparent proxy MAY modify the content-coding if the |
| new coding is known to be acceptable to the recipient, unless the |  | new coding is known to be acceptable to the recipient, unless the |
| "no-transform" cache-control directive is present in the message. |  | "no-transform" cache-control directive is present in the message. |
| If the content-coding of an entity is not "identity", then the |  | If the content-coding of an entity is not "identity", then the |
| response MUST include a Content-Encoding entity-header (Section 5.5) |  | response MUST include a Content-Encoding entity-header (Section 6.5) |
| that lists the non-identity content-coding(s) used. |  | that lists the non-identity content-coding(s) used. |
| If the content-coding of an entity in a request message is not |  | If the content-coding of an entity in a request message is not |
| acceptable to the origin server, the server SHOULD respond with a |  | acceptable to the origin server, the server SHOULD respond with a |
| status code of 415 (Unsupported Media Type). |  | status code of 415 (Unsupported Media Type). |
| If multiple encodings have been applied to an entity, the content |  | If multiple encodings have been applied to an entity, the content |
| codings MUST be listed in the order in which they were applied. |  | codings MUST be listed in the order in which they were applied. |
| Additional information about the encoding parameters MAY be provided |  | Additional information about the encoding parameters MAY be provided |
| by other entity-header fields not defined by this specification. |  | by other entity-header fields not defined by this specification. |
| 5.6. Content-Language |  | 6.6. Content-Language |
| The Content-Language entity-header field describes the natural |  | The Content-Language entity-header field describes the natural |
| language(s) of the intended audience for the enclosed entity. Note |  | language(s) of the intended audience for the enclosed entity. Note |
| that this might not be equivalent to all the languages used within |  | that this might not be equivalent to all the languages used within |
| the entity-body. |  | the entity-body. |
| Content-Language = "Content-Language" ":" 1#language-tag |  | Content-Language = "Content-Language" ":" 1#language-tag |
| Language tags are defined in Section 2.5. The primary purpose of |  | Language tags are defined in Section 3.5. The primary purpose of |
| Content-Language is to allow a user to identify and differentiate |  | Content-Language is to allow a user to identify and differentiate |
| entities according to the user's own preferred language. Thus, if |  | entities according to the user's own preferred language. Thus, if |
| the body content is intended only for a Danish-literate audience, the |  | the body content is intended only for a Danish-literate audience, the |
| appropriate field is |  | appropriate field is |
| Content-Language: da |  | Content-Language: da |
| If no Content-Language is specified, the default is that the content |  | If no Content-Language is specified, the default is that the content |
| is intended for all language audiences. This might mean that the |  | is intended for all language audiences. This might mean that the |
| sender does not consider it to be specific to any natural language, |  | sender does not consider it to be specific to any natural language, |
| skipping to change at page 22, line 44 |  | skipping to change at page 23, line 31 |
| However, just because multiple languages are present within an entity |  | However, just because multiple languages are present within an entity |
| does not mean that it is intended for multiple linguistic audiences. |  | does not mean that it is intended for multiple linguistic audiences. |
| An example would be a beginner's language primer, such as "A First |  | An example would be a beginner's language primer, such as "A First |
| Lesson in Latin," which is clearly intended to be used by an English- |  | Lesson in Latin," which is clearly intended to be used by an English- |
| literate audience. In this case, the Content-Language would properly |  | literate audience. In this case, the Content-Language would properly |
| only include "en". |  | only include "en". |
| Content-Language MAY be applied to any media type -- it is not |  | Content-Language MAY be applied to any media type -- it is not |
| limited to textual documents. |  | limited to textual documents. |
| 5.7. Content-Location |  | 6.7. Content-Location |
| The Content-Location entity-header field MAY be used to supply the |  | The Content-Location entity-header field MAY be used to supply the |
| resource location for the entity enclosed in the message when that |  | resource location for the entity enclosed in the message when that |
| entity is accessible from a location separate from the requested |  | entity is accessible from a location separate from the requested |
| resource's URI. A server SHOULD provide a Content-Location for the |  | resource's URI. A server SHOULD provide a Content-Location for the |
| variant corresponding to the response entity; especially in the case |  | variant corresponding to the response entity; especially in the case |
| where a resource has multiple entities associated with it, and those |  | where a resource has multiple entities associated with it, and those |
| entities actually have separate locations by which they might be |  | entities actually have separate locations by which they might be |
| individually accessed, the server SHOULD provide a Content-Location |  | individually accessed, the server SHOULD provide a Content-Location |
| for the particular variant which is returned. |  | for the particular variant which is returned. |
| skipping to change at page 23, line 16 |  | skipping to change at page 24, line 4 |
| Content-Location = "Content-Location" ":" |  | Content-Location = "Content-Location" ":" |
| ( absoluteURI | relativeURI ) |  | ( absoluteURI | relativeURI ) |
| The value of Content-Location also defines the base URI for the |  | The value of Content-Location also defines the base URI for the |
| entity. |  | entity. |
| The Content-Location value is not a replacement for the original |  | The Content-Location value is not a replacement for the original |
| requested URI; it is only a statement of the location of the resource |  | requested URI; it is only a statement of the location of the resource |
| corresponding to this particular entity at the time of the request. |  | corresponding to this particular entity at the time of the request. |
| Future requests MAY specify the Content-Location URI as the request- |  | Future requests MAY specify the Content-Location URI as the request- |
| URI if the desire is to identify the source of that particular |  | URI if the desire is to identify the source of that particular |
| entity. |  | entity. |
| A cache cannot assume that an entity with a Content-Location |  | A cache cannot assume that an entity with a Content-Location |
| different from the URI used to retrieve it can be used to respond to |  | different from the URI used to retrieve it can be used to respond to |
| later requests on that Content-Location URI. However, the Content- |  | later requests on that Content-Location URI. However, the Content- |
| Location can be used to differentiate between multiple entities |  | Location can be used to differentiate between multiple entities |
| retrieved from a single requested resource, as described in Section 7 |  | retrieved from a single requested resource, as described in Section 8 |
| of [Part6]. |  | of [Part6]. |
| If the Content-Location is a relative URI, the relative URI is |  | If the Content-Location is a relative URI, the relative URI is |
| interpreted relative to the Request-URI. |  | interpreted relative to the Request-URI. |
| The meaning of the Content-Location header in PUT or POST requests is |  | The meaning of the Content-Location header in PUT or POST requests is |
| undefined; servers are free to ignore it in those cases. |  | undefined; servers are free to ignore it in those cases. |
| 5.8. Content-MD5 |  | 6.8. Content-MD5 |
| The Content-MD5 entity-header field, as defined in [RFC1864], is an |  | The Content-MD5 entity-header field, as defined in [RFC1864], is an |
| MD5 digest of the entity-body for the purpose of providing an end-to- |  | MD5 digest of the entity-body for the purpose of providing an end-to- |
| end message integrity check (MIC) of the entity-body. (Note: a MIC |  | end message integrity check (MIC) of the entity-body. (Note: a MIC |
| is good for detecting accidental modification of the entity-body in |  | is good for detecting accidental modification of the entity-body in |
| transit, but is not proof against malicious attacks.) |  | transit, but is not proof against malicious attacks.) |
| Content-MD5 = "Content-MD5" ":" md5-digest |  | Content-MD5 = "Content-MD5" ":" md5-digest |
| md5-digest = <base64 of 128 bit MD5 digest as per [RFC1864]> |  | md5-digest = <base64 of 128 bit MD5 digest as per [RFC1864]> |
| skipping to change at page 24, line 47 |  | skipping to change at page 25, line 34 |
| in which the application of Content-MD5 to HTTP entity-bodies |  | in which the application of Content-MD5 to HTTP entity-bodies |
| differs from its application to MIME entity-bodies. One is that |  | differs from its application to MIME entity-bodies. One is that |
| HTTP, unlike MIME, does not use Content-Transfer-Encoding, and |  | HTTP, unlike MIME, does not use Content-Transfer-Encoding, and |
| does use Transfer-Encoding and Content-Encoding. Another is that |  | does use Transfer-Encoding and Content-Encoding. Another is that |
| HTTP more frequently uses binary content types than MIME, so it is |  | HTTP more frequently uses binary content types than MIME, so it is |
| worth noting that, in such cases, the byte order used to compute |  | worth noting that, in such cases, the byte order used to compute |
| the digest is the transmission byte order defined for the type. |  | the digest is the transmission byte order defined for the type. |
| Lastly, HTTP allows transmission of text types with any of several |  | Lastly, HTTP allows transmission of text types with any of several |
| line break conventions and not just the canonical form using CRLF. |  | line break conventions and not just the canonical form using CRLF. |
| 5.9. Content-Type |  | 6.9. Content-Type |
| The Content-Type entity-header field indicates the media type of the |  | The Content-Type entity-header field indicates the media type of the |
| entity-body sent to the recipient or, in the case of the HEAD method, |  | entity-body sent to the recipient or, in the case of the HEAD method, |
| the media type that would have been sent had the request been a GET. |  | the media type that would have been sent had the request been a GET. |
| Content-Type = "Content-Type" ":" media-type |  | Content-Type = "Content-Type" ":" media-type |
| Media types are defined in Section 2.3. An example of the field is |  | Media types are defined in Section 3.3. An example of the field is |
| Content-Type: text/html; charset=ISO-8859-4 |  | Content-Type: text/html; charset=ISO-8859-4 |
| Further discussion of methods for identifying the media type of an |  | Further discussion of methods for identifying the media type of an |
| entity is provided in Section 3.2.1. |  | entity is provided in Section 4.2.1. |
| 6. IANA Considerations |  | 7. IANA Considerations |
| TBD. |  | [[anchor1: TBD.]] |
| 7. Security Considerations |  | 8. Security Considerations |
| This section is meant to inform application developers, information |  | This section is meant to inform application developers, information |
| providers, and users of the security limitations in HTTP/1.1 as |  | providers, and users of the security limitations in HTTP/1.1 as |
| described by this document. The discussion does not include |  | described by this document. The discussion does not include |
| definitive solutions to the problems revealed, though it does make |  | definitive solutions to the problems revealed, though it does make |
| some suggestions for reducing security risks. |  | some suggestions for reducing security risks. |
| 7.1. Privacy Issues Connected to Accept Headers |  | 8.1. Privacy Issues Connected to Accept Headers |
| Accept request-headers can reveal information about the user to all |  | Accept request-headers can reveal information about the user to all |
| servers which are accessed. The Accept-Language header in particular |  | servers which are accessed. The Accept-Language header in particular |
| can reveal information the user would consider to be of a private |  | can reveal information the user would consider to be of a private |
| nature, because the understanding of particular languages is often |  | nature, because the understanding of particular languages is often |
| strongly correlated to the membership of a particular ethnic group. |  | strongly correlated to the membership of a particular ethnic group. |
| User agents which offer the option to configure the contents of an |  | User agents which offer the option to configure the contents of an |
| Accept-Language header to be sent in every request are strongly |  | Accept-Language header to be sent in every request are strongly |
| encouraged to let the configuration process include a message which |  | encouraged to let the configuration process include a message which |
| makes the user aware of the loss of privacy involved. |  | makes the user aware of the loss of privacy involved. |
| skipping to change at page 26, line 14 |  | skipping to change at page 27, line 5 |
| many users not behind a proxy, the network address of the host |  | many users not behind a proxy, the network address of the host |
| running the user agent will also serve as a long-lived user |  | running the user agent will also serve as a long-lived user |
| identifier. In environments where proxies are used to enhance |  | identifier. In environments where proxies are used to enhance |
| privacy, user agents ought to be conservative in offering accept |  | privacy, user agents ought to be conservative in offering accept |
| header configuration options to end users. As an extreme privacy |  | header configuration options to end users. As an extreme privacy |
| measure, proxies could filter the accept headers in relayed requests. |  | measure, proxies could filter the accept headers in relayed requests. |
| General purpose user agents which provide a high degree of header |  | General purpose user agents which provide a high degree of header |
| configurability SHOULD warn users about the loss of privacy which can |  | configurability SHOULD warn users about the loss of privacy which can |
| be involved. |  | be involved. |
| 7.2. Content-Disposition Issues |  | 8.2. Content-Disposition Issues |
| [RFC1806], from which the often implemented Content-Disposition (see |  | [RFC1806], from which the often implemented Content-Disposition (see |
| Appendix B.1) header in HTTP is derived, has a number of very serious |  | Appendix B.1) header in HTTP is derived, has a number of very serious |
| security considerations. Content-Disposition is not part of the HTTP |  | security considerations. Content-Disposition is not part of the HTTP |
| standard, but since it is widely implemented, we are documenting its |  | standard, but since it is widely implemented, we are documenting its |
| use and risks for implementors. See [RFC2183] (which updates |  | use and risks for implementors. See [RFC2183] (which updates |
| [RFC1806]) for details. |  | [RFC1806]) for details. |
| 8. Acknowledgments |  | 9. Acknowledgments |
| 9. References |  | 10. References |
| 9.1. Normative References |  | 10.1. Normative References |
| [ISO-8859-1] |  | [ISO-8859-1] |
| International Organization for Standardization, |  | International Organization for Standardization, |
| "Information technology -- 8-bit single-byte coded graphic |  | "Information technology -- 8-bit single-byte coded graphic |
| character sets -- Part 1: Latin alphabet No. 1", ISO/ |  | character sets -- Part 1: Latin alphabet No. 1", ISO/ |
| IEC 8859-1:1998, 1998. |  | IEC 8859-1:1998, 1998. |
| [Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |  | [Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |
| and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections, |  | and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections, |
| and Message Parsing", draft-ietf-httpbis-p1-messaging-01 |  | and Message Parsing", draft-ietf-httpbis-p1-messaging-02 |
| (work in progress), January 2008. |  | (work in progress), February 2008. |
| [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., Ed., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |
| and J. Reschke, Ed., "HTTP/1.1, part 2: Message |  | and J. Reschke, Ed., "HTTP/1.1, part 2: Message |
| Semantics", draft-ietf-httpbis-p2-semantics-01 (work in |  | Semantics", draft-ietf-httpbis-p2-semantics-02 (work in |
| progress), January 2008. |  | progress), February 2008. |
| [Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |  | [Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |
| and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional |  | and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional |
| Requests", draft-ietf-httpbis-p4-conditional-01 (work in |  | Requests", draft-ietf-httpbis-p4-conditional-02 (work in |
| progress), January 2008. |  | progress), February 2008. |
| [Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |  | [Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |
| and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and |  | and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and |
| Partial Responses", draft-ietf-httpbis-p5-range-01 (work |  | Partial Responses", draft-ietf-httpbis-p5-range-02 (work |
| in progress), January 2008. |  | in progress), February 2008. |
| [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., Ed., |  | Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed., |
| and J. Reschke, Ed., "HTTP/1.1, part 6: Caching", |  | and J. Reschke, Ed., "HTTP/1.1, part 6: Caching", |
| draft-ietf-httpbis-p6-cache-01 (work in progress), |  | draft-ietf-httpbis-p6-cache-02 (work in progress), |
| January 2008. |  | February 2008. |
| [RFC1766] Alvestrand, H., "Tags for the Identification of |  | [RFC1766] Alvestrand, H., "Tags for the Identification of |
| Languages", RFC 1766, March 1995. |  | Languages", RFC 1766, March 1995. |
| [RFC1864] Myers, J. and M. Rose, "The Content-MD5 Header Field", |  | [RFC1864] Myers, J. and M. Rose, "The Content-MD5 Header Field", |
| RFC 1864, October 1995. |  | RFC 1864, October 1995. |
| [RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format |  | [RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format |
| Specification version 3.3", RFC 1950, May 1996. |  | Specification version 3.3", RFC 1950, May 1996. |
| skipping to change at page 28, line 16 |  | skipping to change at page 29, line 6 |
| Extensions (MIME) Part One: Format of Internet Message |  | Extensions (MIME) Part One: Format of Internet Message |
| Bodies", RFC 2045, November 1996. |  | Bodies", RFC 2045, November 1996. |
| [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail |  | [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail |
| Extensions (MIME) Part Two: Media Types", RFC 2046, |  | Extensions (MIME) Part Two: Media Types", RFC 2046, |
| November 1996. |  | November 1996. |
| [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. |
| [RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and |  | 10.2. Informative References |
| Registration Procedures", BCP 13, RFC 4288, December 2005. |  |  |
| 9.2. Informative References |  |  |
| [RFC1806] Troost, R. and S. Dorner, "Communicating Presentation |  | [RFC1806] Troost, R. and S. Dorner, "Communicating Presentation |
| Information in Internet Messages: The Content-Disposition |  | Information in Internet Messages: The Content-Disposition |
| Header", RFC 1806, June 1995. |  | Header", RFC 1806, June 1995. |
| [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext |  | [RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext |
| Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996. |  | Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996. |
| [RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail |  | [RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail |
| Extensions (MIME) Part Five: Conformance Criteria and |  | Extensions (MIME) Part Five: Conformance Criteria and |
| skipping to change at page 29, line 15 |  | skipping to change at page 29, line 50 |
| [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., |  | [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., |
| Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext |  | Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext |
| Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. |  | Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. |
| [RFC2822] Resnick, P., "Internet Message Format", RFC 2822, |  | [RFC2822] Resnick, P., "Internet Message Format", RFC 2822, |
| April 2001. |  | April 2001. |
| [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO |  | [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO |
| 10646", RFC 3629, STD 63, November 2003. |  | 10646", RFC 3629, STD 63, November 2003. |
|  |  | [RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and |
|  |  | Registration Procedures", BCP 13, RFC 4288, December 2005. |
| Appendix A. Differences Between HTTP Entities and RFC 2045 Entities |  | Appendix A. Differences Between HTTP Entities and RFC 2045 Entities |
| HTTP/1.1 uses many of the constructs defined for Internet Mail |  | HTTP/1.1 uses many of the constructs defined for Internet Mail |
| ([RFC2822]) and the Multipurpose Internet Mail Extensions (MIME |  | ([RFC2822]) and the Multipurpose Internet Mail Extensions (MIME |
| [RFC2045]) to allow entities to be transmitted in an open variety of |  | [RFC2045]) to allow entities to be transmitted in an open variety of |
| representations and with extensible mechanisms. However, RFC 2045 |  | representations and with extensible mechanisms. However, RFC 2045 |
| discusses mail, and HTTP has a few features that are different from |  | discusses mail, and HTTP has a few features that are different from |
| those described in RFC 2045. These differences were carefully chosen |  | those described in RFC 2045. These differences were carefully chosen |
| to optimize performance over binary connections, to allow greater |  | to optimize performance over binary connections, to allow greater |
| freedom in the use of new media types, to make date comparisons |  | freedom in the use of new media types, to make date comparisons |
| skipping to change at page 30, line 9 |  | skipping to change at page 30, line 45 |
| MIME-Version = "MIME-Version" ":" 1*DIGIT "." 1*DIGIT |  | MIME-Version = "MIME-Version" ":" 1*DIGIT "." 1*DIGIT |
| MIME version "1.0" is the default for use in HTTP/1.1. However, |  | MIME version "1.0" is the default for use in HTTP/1.1. However, |
| HTTP/1.1 message parsing and semantics are defined by this document |  | HTTP/1.1 message parsing and semantics are defined by this document |
| and not the MIME specification. |  | and not the MIME specification. |
| A.2. Conversion to Canonical Form |  | A.2. Conversion to Canonical Form |
| [RFC2045] requires that an Internet mail entity be converted to |  | [RFC2045] requires that an Internet mail entity be converted to |
| canonical form prior to being transferred, as described in Section 4 |  | canonical form prior to being transferred, as described in Section 4 |
| of [RFC2049]. Section 2.3.1 of this document describes the forms |  | of [RFC2049]. Section 3.3.1 of this document describes the forms |
| allowed for subtypes of the "text" media type when transmitted over |  | allowed for subtypes of the "text" media type when transmitted over |
| HTTP. [RFC2046] requires that content with a type of "text" |  | HTTP. [RFC2046] requires that content with a type of "text" |
| represent line breaks as CRLF and forbids the use of CR or LF outside |  | represent line breaks as CRLF and forbids the use of CR or LF outside |
| of line break sequences. HTTP allows CRLF, bare CR, and bare LF to |  | of line break sequences. HTTP allows CRLF, bare CR, and bare LF to |
| indicate a line break within text content when a message is |  | indicate a line break within text content when a message is |
| transmitted over HTTP. |  | transmitted over HTTP. |
| Where it is possible, a proxy or gateway from HTTP to a strict MIME |  | Where it is possible, a proxy or gateway from HTTP to a strict MIME |
| environment SHOULD translate all line breaks within the text media |  | environment SHOULD translate all line breaks within the text media |
| types described in Section 2.3.1 of this document to the RFC 2049 |  | types described in Section 3.3.1 of this document to the RFC 2049 |
| canonical form of CRLF. Note, however, that this might be |  | canonical form of CRLF. Note, however, that this might be |
| complicated by the presence of a Content-Encoding and by the fact |  | complicated by the presence of a Content-Encoding and by the fact |
| that HTTP allows the use of some character sets which do not use |  | that HTTP allows the use of some character sets which do not use |
| octets 13 and 10 to represent CR and LF, as is the case for some |  | octets 13 and 10 to represent CR and LF, as is the case for some |
| multi-byte character sets. |  | multi-byte character sets. |
| Implementors should note that conversion will break any cryptographic |  | Implementors should note that conversion will break any cryptographic |
| checksums applied to the original content unless the original content |  | checksums applied to the original content unless the original content |
| is already in canonical form. Therefore, the canonical form is |  | is already in canonical form. Therefore, the canonical form is |
| recommended for any content that uses such checksums in HTTP. |  | recommended for any content that uses such checksums in HTTP. |
| skipping to change at page 31, line 23 |  | skipping to change at page 32, line 13 |
| to forwarding a message via a MIME-compliant protocol. |  | to forwarding a message via a MIME-compliant protocol. |
| A.6. MHTML and Line Length Limitations |  | A.6. MHTML and Line Length Limitations |
| HTTP implementations which share code with MHTML [RFC2557] |  | HTTP implementations which share code with MHTML [RFC2557] |
| implementations need to be aware of MIME line length limitations. |  | implementations need to be aware of MIME line length limitations. |
| Since HTTP does not have this limitation, HTTP does not fold long |  | Since HTTP does not have this limitation, HTTP does not fold long |
| lines. MHTML messages being transported by HTTP follow all |  | lines. MHTML messages being transported by HTTP follow all |
| conventions of MHTML, including line length limitations and folding, |  | conventions of MHTML, including line length limitations and folding, |
| canonicalization, etc., since HTTP transports all message-bodies as |  | canonicalization, etc., since HTTP transports all message-bodies as |
| payload (see Section 2.3.2) and does not interpret the content or any |  | payload (see Section 3.3.2) and does not interpret the content or any |
| MIME header lines that might be contained therein. |  | MIME header lines that might be contained therein. |
| Appendix B. Additional Features |  | Appendix B. Additional Features |
| [RFC1945] and [RFC2068] document protocol elements used by some |  | [RFC1945] and [RFC2068] document protocol elements used by some |
| existing HTTP implementations, but not consistently and correctly |  | existing HTTP implementations, but not consistently and correctly |
| across most HTTP/1.1 applications. Implementors are advised to be |  | across most HTTP/1.1 applications. Implementors are advised to be |
| aware of these features, but cannot rely upon their presence in, or |  | aware of these features, but cannot rely upon their presence in, or |
| interoperability with, other HTTP/1.1 applications. Some of these |  | interoperability with, other HTTP/1.1 applications. Some of these |
| describe proposed experimental features, and some describe features |  | describe proposed experimental features, and some describe features |
| skipping to change at page 32, line 20 |  | skipping to change at page 33, line 4 |
| disp-extension-token = token |  | disp-extension-token = token |
| disp-extension-parm = token "=" ( token | quoted-string ) |  | disp-extension-parm = token "=" ( token | quoted-string ) |
| An example is |  | An example is |
| Content-Disposition: attachment; filename="fname.ext" |  | Content-Disposition: attachment; filename="fname.ext" |
| The receiving user agent SHOULD NOT respect any directory path |  | The receiving user agent SHOULD NOT respect any directory path |
| information present in the filename-parm parameter, which is the only |  | information present in the filename-parm parameter, which is the only |
| parameter believed to apply to HTTP implementations at this time. |  | parameter believed to apply to HTTP implementations at this time. |
| The filename SHOULD be treated as a terminal component only. |  | The filename SHOULD be treated as a terminal component only. |
| If this header is used in a response with the application/ |  | If this header is used in a response with the application/ |
| octet-stream content-type, the implied suggestion is that the user |  | octet-stream content-type, the implied suggestion is that the user |
| agent should not display the response, but directly enter a `save |  | agent should not display the response, but directly enter a `save |
| response as...' dialog. |  | response as...' dialog. |
| See Section 7.2 for Content-Disposition security issues. |  | See Section 8.2 for Content-Disposition security issues. |
| Appendix C. Compatibility with Previous Versions |  | Appendix C. Compatibility with Previous Versions |
| C.1. Changes from RFC 2068 |  | C.1. Changes from RFC 2068 |
| Transfer-coding and message lengths all interact in ways that |  | Transfer-coding and message lengths all interact in ways that |
| required fixing exactly when chunked encoding is used (to allow for |  | required fixing exactly when chunked encoding is used (to allow for |
| transfer encoding that may not be self delimiting); it was important |  | transfer encoding that may not be self delimiting); it was important |
| to straighten out exactly how message lengths are computed. |  | to straighten out exactly how message lengths are computed. |
| (Section 3.2.2, see also [Part1], [Part5] and [Part6]). |  | (Section 4.2.2, see also [Part1], [Part5] and [Part6]). |
| Charset wildcarding is introduced to avoid explosion of character set |  | Charset wildcarding is introduced to avoid explosion of character set |
| names in accept headers. (Section 5.2) |  | names in accept headers. (Section 6.2) |
| Content-Base was deleted from the specification: it was not |  | Content-Base was deleted from the specification: it was not |
| implemented widely, and there is no simple, safe way to introduce it |  | implemented widely, and there is no simple, safe way to introduce it |
| without a robust extension mechanism. In addition, it is used in a |  | without a robust extension mechanism. In addition, it is used in a |
| similar, but not identical fashion in MHTML [RFC2557]. |  | similar, but not identical fashion in MHTML [RFC2557]. |
| A content-coding of "identity" was introduced, to solve problems |  | A content-coding of "identity" was introduced, to solve problems |
| discovered in caching. (Section 2.2) |  | discovered in caching. (Section 3.2) |
| Quality Values of zero should indicate that "I don't want something" |  | Quality Values of zero should indicate that "I don't want something" |
| to allow clients to refuse a representation. (Section 2.4) |  | to allow clients to refuse a representation. (Section 3.4) |
| The Alternates, Content-Version, Derived-From, Link, URI, Public and |  | The Alternates, Content-Version, Derived-From, Link, URI, Public and |
| Content-Base header fields were defined in previous versions of this |  | Content-Base header fields were defined in previous versions of this |
| specification, but not commonly implemented. See [RFC2068]. |  | specification, but not commonly implemented. See [RFC2068]. |
| C.2. Changes from RFC 2616 |  | C.2. Changes from RFC 2616 |
| Clarify contexts that charset is used in. (Section 2.1) |  | Clarify contexts that charset is used in. (Section 3.1) |
| Remove reference to non-existant identity transfer-coding value |  | Remove reference to non-existant identity transfer-coding value |
| tokens. (Appendix A.4) |  | tokens. (Appendix A.4) |
| Appendix D. Change Log (to be removed by RFC Editor before publication) |  | Appendix D. Change Log (to be removed by RFC Editor before publication) |
| D.1. Since RFC2616 |  | D.1. Since RFC2616 |
| Extracted relevant partitions from [RFC2616]. |  | Extracted relevant partitions from [RFC2616]. |
| skipping to change at page 33, line 45 |  | skipping to change at page 34, line 35 |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/25>: "Accept- |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/25>: "Accept- |
| Encoding BNF" |  | Encoding BNF" |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35>: "Normative |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35>: "Normative |
| and Informative references" |  | and Informative references" |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/46>: "RFC1700 |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/46>: "RFC1700 |
| references" |  | references" |
|  |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/55>: "Updating |
|  |  | to RFC4288" |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/65>: |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/65>: |
| "Informative references" |  | "Informative references" |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/66>: |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/66>: |
| "ISO-8859-1 Reference" |  | "ISO-8859-1 Reference" |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/68>: "Encoding |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/68>: "Encoding |
| References Normative" |  | References Normative" |
| o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86>: "Normative |  | o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86>: "Normative |
| up-to-date references" |  | up-to-date references" |
|  |  | D.3. Since draft-ietf-httpbis-p3-payload-01 |
|  |  | Ongoing work on ABNF conversion |
|  |  | (<http://www3.tools.ietf.org/wg/httpbis/trac/ticket/36>): |
|  |  | o Add explicit references to BNF syntax and rules imported from |
|  |  | other parts of the specification. |
| Index |  | Index |
| A |  | A |
| Accept header 16 |  | Accept header 16 |
| Accept-Charset header 18 |  | Accept-Charset header 18 |
| Accept-Encoding header 18 |  | Accept-Encoding header 19 |
| Accept-Language header 20 |  | Accept-Language header 20 |
| Alternates header 33 |  | Alternates header 33 |
| C |  | C |
| compress 7 |  | compress 8 |
| Content-Base header 33 |  | Content-Base header 33 |
| Content-Disposition header 31 |  | Content-Disposition header 32 |
| Content-Encoding header 21 |  | Content-Encoding header 22 |
| Content-Language header 22 |  | Content-Language header 22 |
| Content-Location header 22 |  | Content-Location header 23 |
| Content-MD5 header 23 |  | Content-MD5 header 24 |
| Content-Type header 24 |  | Content-Type header 25 |
| Content-Version header 33 |  | Content-Version header 33 |
| D |  | D |
| deflate 7 |  | deflate 8 |
| Derived-From header 33 |  | Derived-From header 33 |
| G |  | G |
| Grammar |  | Grammar |
| Accept 16 |  | Accept 16 |
| Accept-Charset 18 |  | Accept-Charset 18 |
| Accept-Encoding 18 |  | Accept-Encoding 19 |
| accept-extension 16 |  | accept-extension 16 |
| Accept-Language 20 |  | Accept-Language 20 |
| accept-params 16 |  | accept-params 16 |
| attribute 8 |  | attribute 9 |
| charset 6 |  | charset 7 |
| codings 18 |  | codings 19 |
| content-coding 7 |  | content-coding 7 |
| content-disposition 32 |  | content-disposition 32 |
| Content-Encoding 21 |  | Content-Encoding 22 |
| Content-Language 22 |  | Content-Language 22 |
| Content-Location 23 |  | Content-Location 23 |
| Content-MD5 23 |  | Content-MD5 24 |
| Content-Type 24 |  | Content-Type 25 |
| disp-extension-parm 32 |  | disp-extension-parm 32 |
| disp-extension-token 32 |  | disp-extension-token 32 |
| disposition-parm 32 |  | disposition-parm 32 |
| disposition-type 32 |  | disposition-type 32 |
| entity-body 12 |  | entity-body 12 |
| entity-header 11 |  | entity-header 12 |
| extension-header 11 |  | extension-header 12 |
| filename-parm 32 |  | filename-parm 32 |
| language-range 20 |  | language-range 20 |
| language-tag 11 |  | language-tag 11 |
| md5-digest 23 |  | md5-digest 24 |
| media-range 16 |  | media-range 16 |
| media-type 8 |  | media-type 9 |
| MIME-Version 29 |  | MIME-Version 30 |
| parameter 8 |  | parameter 9 |
| primary-tag 11 |  | primary-tag 11 |
| qvalue 10 |  | qvalue 11 |
| subtag 11 |  | subtag 11 |
| subtype 8 |  | subtype 9 |
| type 8 |  | type 9 |
| value 8 |  | value 9 |
| gzip 7 |  | gzip 8 |
| H |  | H |
| Headers |  | Headers |
| Accept 16 |  | Accept 16 |
| Accept-Charset 18 |  | Accept-Charset 18 |
| Accept-Encoding 18 |  | Accept-Encoding 19 |
| Accept-Language 20 |  | Accept-Language 20 |
| Alternate 33 |  | Alternate 33 |
| Content-Base 33 |  | Content-Base 33 |
| Content-Disposition 31 |  | Content-Disposition 32 |
| Content-Encoding 21 |  | Content-Encoding 22 |
| Content-Language 22 |  | Content-Language 22 |
| Content-Location 22 |  | Content-Location 23 |
| Content-MD5 23 |  | Content-MD5 24 |
| Content-Type 24 |  | Content-Type 25 |
| Content-Version 33 |  | Content-Version 33 |
| Derived-From 33 |  | Derived-From 33 |
| Link 33 |  | Link 33 |
| Public 33 |  | Public 33 |
| URI 33 |  | URI 33 |
| I |  | I |
| identity 8 |  | identity 8 |
| L |  | L |
| Link header 33 |  | Link header 33 |
| P |  | P |
| Public header 33 |  | Public header 33 |
| U |  | U |
| URI header 33 |  | URI header 33 |
| Authors' Addresses |  | Authors' Addresses |
End of changes. 108 change blocks.
| 180 lines changed or deleted |  | 223 lines changed or added |
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