source: draft-ietf-httpbis/latest/p3-payload.xml @ 1446

Last change on this file since 1446 was 1443, checked in by julian.reschke@…, 8 years ago

bump up document dates; update to latest version of rfc2629.xslt.

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1<?xml version="1.0" encoding="utf-8"?>
2<?xml-stylesheet type='text/xsl' href='../myxml2rfc.xslt'?>
3<!DOCTYPE rfc [
4  <!ENTITY MAY "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MAY</bcp14>">
5  <!ENTITY MUST "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST</bcp14>">
6  <!ENTITY MUST-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST NOT</bcp14>">
7  <!ENTITY OPTIONAL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>OPTIONAL</bcp14>">
8  <!ENTITY RECOMMENDED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>RECOMMENDED</bcp14>">
9  <!ENTITY REQUIRED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>REQUIRED</bcp14>">
10  <!ENTITY SHALL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL</bcp14>">
11  <!ENTITY SHALL-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL NOT</bcp14>">
12  <!ENTITY SHOULD "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD</bcp14>">
13  <!ENTITY SHOULD-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD NOT</bcp14>">
14  <!ENTITY ID-VERSION "latest">
15  <!ENTITY ID-MONTH "October">
16  <!ENTITY ID-YEAR "2011">
17  <!ENTITY mdash "&#8212;">
18  <!ENTITY notation                 "<xref target='Part1' x:rel='#notation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
19  <!ENTITY notation-abnf            "<xref target='Part1' x:rel='#notation.abnf' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
20  <!ENTITY acks                     "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
21  <!ENTITY basic-rules              "<xref target='Part1' x:rel='#basic.rules' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
22  <!ENTITY field-rules              "<xref target='Part1' x:rel='#field.rules' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY caching-neg-resp         "<xref target='Part6' x:rel='#caching.negotiated.responses' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY header-transfer-encoding "<xref target='Part1' x:rel='#header.transfer-encoding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY header-content-length    "<xref target='Part1' x:rel='#header.content-length' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY header-content-range     "<xref target='Part5' x:rel='#header.content-range' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY header-expires           "<xref target='Part6' x:rel='#header.expires' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY header-last-modified     "<xref target='Part4' x:rel='#header.last-modified' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29  <!ENTITY header-user-agent        "<xref target='Part2' x:rel='#header.user-agent' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
30  <!ENTITY header-vary              "<xref target='Part6' x:rel='#header.vary' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
31  <!ENTITY message-body             "<xref target='Part1' x:rel='#message.body' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
32  <!ENTITY multipart-byteranges     "<xref target='Part5' x:rel='#internet.media.type.multipart.byteranges' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
33  <!ENTITY http-date                "<xref target='Part2' x:rel='#http.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
34  <!ENTITY qvalue                   "<xref target='Part1' x:rel='#quality.values' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
35  <!ENTITY uri                      "<xref target='Part1' x:rel='#uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
36  <!ENTITY effective-request-uri    "<xref target='Part1' x:rel='#effective.request.uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
37  <!ENTITY compression-codings      "<xref target='Part1' x:rel='#compression.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
38  <!ENTITY transfer-codings         "<xref target='Part1' x:rel='#transfer.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
39  <!ENTITY compress-coding          "<xref target='Part1' x:rel='#compress.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
40  <!ENTITY deflate-coding           "<xref target='Part1' x:rel='#deflate.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
41  <!ENTITY gzip-coding              "<xref target='Part1' x:rel='#gzip.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
42  <!ENTITY response-representation  "<xref target='Part2' x:rel='#identifying.response.associated.with.representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
43]>
44<?rfc toc="yes" ?>
45<?rfc symrefs="yes" ?>
46<?rfc sortrefs="yes" ?>
47<?rfc compact="yes"?>
48<?rfc subcompact="no" ?>
49<?rfc linkmailto="no" ?>
50<?rfc editing="no" ?>
51<?rfc comments="yes"?>
52<?rfc inline="yes"?>
53<?rfc rfcedstyle="yes"?>
54<?rfc-ext allow-markup-in-artwork="yes" ?>
55<?rfc-ext include-references-in-index="yes" ?>
56<rfc obsoletes="2616" category="std" x:maturity-level="draft"
57     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p3-payload-&ID-VERSION;"
58     xmlns:x='http://purl.org/net/xml2rfc/ext'>
59<front>
60
61  <title abbrev="HTTP/1.1, Part 3">HTTP/1.1, part 3: Message Payload and Content Negotiation</title>
62
63  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
64    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
65    <address>
66      <postal>
67        <street>345 Park Ave</street>
68        <city>San Jose</city>
69        <region>CA</region>
70        <code>95110</code>
71        <country>USA</country>
72      </postal>
73      <email>fielding@gbiv.com</email>
74      <uri>http://roy.gbiv.com/</uri>
75    </address>
76  </author>
77
78  <author initials="J." surname="Gettys" fullname="Jim Gettys">
79    <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
80    <address>
81      <postal>
82        <street>21 Oak Knoll Road</street>
83        <city>Carlisle</city>
84        <region>MA</region>
85        <code>01741</code>
86        <country>USA</country>
87      </postal>
88      <email>jg@freedesktop.org</email>
89      <uri>http://gettys.wordpress.com/</uri>
90    </address>
91  </author>
92 
93  <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
94    <organization abbrev="HP">Hewlett-Packard Company</organization>
95    <address>
96      <postal>
97        <street>HP Labs, Large Scale Systems Group</street>
98        <street>1501 Page Mill Road, MS 1177</street>
99        <city>Palo Alto</city>
100        <region>CA</region>
101        <code>94304</code>
102        <country>USA</country>
103      </postal>
104      <email>JeffMogul@acm.org</email>
105    </address>
106  </author>
107
108  <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
109    <organization abbrev="Microsoft">Microsoft Corporation</organization>
110    <address>
111      <postal>
112        <street>1 Microsoft Way</street>
113        <city>Redmond</city>
114        <region>WA</region>
115        <code>98052</code>
116        <country>USA</country>
117      </postal>
118      <email>henrikn@microsoft.com</email>
119    </address>
120  </author>
121
122  <author initials="L." surname="Masinter" fullname="Larry Masinter">
123    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
124    <address>
125      <postal>
126        <street>345 Park Ave</street>
127        <city>San Jose</city>
128        <region>CA</region>
129        <code>95110</code>
130        <country>USA</country>
131      </postal>
132      <email>LMM@acm.org</email>
133      <uri>http://larry.masinter.net/</uri>
134    </address>
135  </author>
136 
137  <author initials="P." surname="Leach" fullname="Paul J. Leach">
138    <organization abbrev="Microsoft">Microsoft Corporation</organization>
139    <address>
140      <postal>
141        <street>1 Microsoft Way</street>
142        <city>Redmond</city>
143        <region>WA</region>
144        <code>98052</code>
145      </postal>
146      <email>paulle@microsoft.com</email>
147    </address>
148  </author>
149   
150  <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
151    <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
152    <address>
153      <postal>
154        <street>MIT Computer Science and Artificial Intelligence Laboratory</street>
155        <street>The Stata Center, Building 32</street>
156        <street>32 Vassar Street</street>
157        <city>Cambridge</city>
158        <region>MA</region>
159        <code>02139</code>
160        <country>USA</country>
161      </postal>
162      <email>timbl@w3.org</email>
163      <uri>http://www.w3.org/People/Berners-Lee/</uri>
164    </address>
165  </author>
166
167  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
168    <organization abbrev="W3C">World Wide Web Consortium</organization>
169    <address>
170      <postal>
171        <street>W3C / ERCIM</street>
172        <street>2004, rte des Lucioles</street>
173        <city>Sophia-Antipolis</city>
174        <region>AM</region>
175        <code>06902</code>
176        <country>France</country>
177      </postal>
178      <email>ylafon@w3.org</email>
179      <uri>http://www.raubacapeu.net/people/yves/</uri>
180    </address>
181  </author>
182
183  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
184    <organization abbrev="greenbytes">greenbytes GmbH</organization>
185    <address>
186      <postal>
187        <street>Hafenweg 16</street>
188        <city>Muenster</city><region>NW</region><code>48155</code>
189        <country>Germany</country>
190      </postal>
191      <phone>+49 251 2807760</phone>
192      <facsimile>+49 251 2807761</facsimile>
193      <email>julian.reschke@greenbytes.de</email>
194      <uri>http://greenbytes.de/tech/webdav/</uri>
195    </address>
196  </author>
197
198  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
199  <workgroup>HTTPbis Working Group</workgroup>
200
201<abstract>
202<t>
203   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
204   distributed, collaborative, hypertext information systems. HTTP has been in
205   use by the World Wide Web global information initiative since 1990. This
206   document is Part 3 of the seven-part specification that defines the protocol
207   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
208</t>
209<t>
210   Part 3 defines HTTP message content, metadata, and content negotiation.
211</t>
212</abstract>
213
214<note title="Editorial Note (To be removed by RFC Editor)">
215  <t>
216    Discussion of this draft should take place on the HTTPBIS working group
217    mailing list (ietf-http-wg@w3.org), which is archived at
218    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
219  </t>
220  <t>
221    The current issues list is at
222    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
223    documents (including fancy diffs) can be found at
224    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
225  </t>
226  <t>
227    The changes in this draft are summarized in <xref target="changes.since.16"/>.
228  </t>
229</note>
230</front>
231<middle>
232<section title="Introduction" anchor="introduction">
233<t>
234   This document defines HTTP/1.1 message payloads (a.k.a., content), the
235   associated metadata header fields that define how the payload is intended
236   to be interpreted by a recipient, the request header fields that
237   might influence content selection, and the various selection algorithms
238   that are collectively referred to as HTTP content negotiation.
239</t>
240<t>
241   This document is currently disorganized in order to minimize the changes
242   between drafts and enable reviewers to see the smaller errata changes.
243   A future draft will reorganize the sections to better reflect the content.
244   In particular, the sections on entities will be renamed payload and moved
245   to the first half of the document, while the sections on content negotiation
246   and associated request header fields will be moved to the second half.  The
247   current mess reflects how widely dispersed these topics and associated
248   requirements had become in <xref target="RFC2616"/>.
249</t>
250
251<section title="Terminology" anchor="terminology">
252<t>
253   This specification uses a number of terms to refer to the roles
254   played by participants in, and objects of, the HTTP communication.
255</t>
256<t>
257  <iref item="content negotiation"/>
258  <x:dfn>content negotiation</x:dfn>
259  <list>
260    <t>
261      The mechanism for selecting the appropriate representation when
262      servicing a request. The representation in any response
263      can be negotiated (including error responses).
264    </t>
265  </list>
266</t>
267</section>
268
269<section title="Requirements" anchor="intro.requirements">
270<t>
271   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
272   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
273   document are to be interpreted as described in <xref target="RFC2119"/>.
274</t>
275<t>
276   An implementation is not compliant if it fails to satisfy one or more
277   of the "MUST" or "REQUIRED" level requirements for the protocols it
278   implements. An implementation that satisfies all the "MUST" or "REQUIRED"
279   level and all the "SHOULD" level requirements for its protocols is said
280   to be "unconditionally compliant"; one that satisfies all the "MUST"
281   level requirements but not all the "SHOULD" level requirements for its
282   protocols is said to be "conditionally compliant".
283</t>
284</section>
285
286<section title="Syntax Notation" anchor="notation">
287  <x:anchor-alias value="ALPHA"/>
288  <x:anchor-alias value="CR"/>
289  <x:anchor-alias value="DIGIT"/>
290  <x:anchor-alias value="LF"/>
291  <x:anchor-alias value="OCTET"/>
292  <x:anchor-alias value="VCHAR"/>
293<t>
294  This specification uses the ABNF syntax defined in &notation; (which
295  extends the syntax defined in <xref target="RFC5234"/> with a list rule).
296  <xref target="collected.abnf"/> shows the collected ABNF, with the list
297  rule expanded.
298</t>
299<t>
300  The following core rules are included by
301  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
302  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
303  DIGIT (decimal 0-9), DQUOTE (double quote),
304  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
305  OCTET (any 8-bit sequence of data), SP (space), and
306  VCHAR (any visible US-ASCII character).
307</t>
308
309<section title="Core Rules" anchor="core.rules">
310  <x:anchor-alias value="token"/>
311  <x:anchor-alias value="word"/>
312  <x:anchor-alias value="OWS"/>
313<t>
314  The core rules below are defined in <xref target="Part1"/>:
315</t>
316<figure><artwork type="abnf2616">
317  <x:ref>OWS</x:ref>            = &lt;OWS, defined in &basic-rules;&gt;
318  <x:ref>token</x:ref>          = &lt;token, defined in &field-rules;&gt;
319  <x:ref>word</x:ref>           = &lt;word, defined in &field-rules;&gt;
320</artwork></figure>
321</section>
322
323<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
324  <x:anchor-alias value="absolute-URI"/>
325  <x:anchor-alias value="partial-URI"/>
326  <x:anchor-alias value="qvalue"/>
327<t>
328  The ABNF rules below are defined in other parts:
329</t>
330<figure><!--Part1--><artwork type="abnf2616">
331  <x:ref>absolute-URI</x:ref>   = &lt;absolute-URI, defined in &uri;&gt;
332  <x:ref>partial-URI</x:ref>    = &lt;partial-URI, defined in &uri;&gt;
333  <x:ref>qvalue</x:ref>         = &lt;qvalue, defined in &qvalue;&gt;
334</artwork></figure>
335</section>
336
337</section>
338
339</section>
340
341<section title="Protocol Parameters" anchor="protocol.parameters">
342
343<section title="Character Encodings (charset)" anchor="character.sets">
344<t>
345   HTTP uses charset names to indicate the character encoding of a
346   textual representation.
347</t>
348<t anchor="rule.charset">
349  <x:anchor-alias value="charset"/>
350   A character encoding is identified by a case-insensitive token. The
351   complete set of tokens is defined by the IANA Character Set registry
352   (<eref target="http://www.iana.org/assignments/character-sets"/>).
353</t>
354<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="charset"/>
355  <x:ref>charset</x:ref> = <x:ref>token</x:ref>
356</artwork></figure>
357<t>
358   Although HTTP allows an arbitrary token to be used as a charset
359   value, any token that has a predefined value within the IANA
360   Character Set registry &MUST; represent the character encoding defined
361   by that registry. Applications &SHOULD; limit their use of character
362   encodings to those defined within the IANA registry.
363</t>
364<t>
365   HTTP uses charset in two contexts: within an Accept-Charset request
366   header field (in which the charset value is an unquoted token) and as the
367   value of a parameter in a Content-Type header field (within a request or
368   response), in which case the parameter value of the charset parameter
369   can be quoted.
370</t>
371<t>
372   Implementors need to be aware of IETF character set requirements <xref target="RFC3629"/>
373   <xref target="RFC2277"/>.
374</t>
375</section>
376
377<section title="Content Codings" anchor="content.codings">
378  <x:anchor-alias value="content-coding"/>
379<t>
380   Content coding values indicate an encoding transformation that has
381   been or can be applied to a representation. Content codings are primarily
382   used to allow a representation to be compressed or otherwise usefully
383   transformed without losing the identity of its underlying media type
384   and without loss of information. Frequently, the representation is stored in
385   coded form, transmitted directly, and only decoded by the recipient.
386</t>
387<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="content-coding"/>
388  <x:ref>content-coding</x:ref>   = <x:ref>token</x:ref>
389</artwork></figure>
390<t>
391   All content-coding values are case-insensitive. HTTP/1.1 uses
392   content-coding values in the Accept-Encoding (<xref target="header.accept-encoding"/>) and
393   Content-Encoding (<xref target="header.content-encoding"/>) header fields. Although the value
394   describes the content-coding, what is more important is that it
395   indicates what decoding mechanism will be required to remove the
396   encoding.
397</t>
398<t>
399   compress<iref item="compress (Coding Format)"/><iref item="Coding Format" subitem="compress"/>
400  <list>
401    <t>
402      See &compress-coding;.
403    </t>
404  </list>
405</t>
406<t>
407   deflate<iref item="deflate (Coding Format)"/><iref item="Coding Format" subitem="deflate"/>
408  <list>
409    <t>
410      See &deflate-coding;.
411    </t>
412  </list>
413</t>
414<t>
415   gzip<iref item="gzip (Coding Format)"/><iref item="Coding Format" subitem="gzip"/>
416  <list>
417    <t>
418      See &gzip-coding;.
419    </t>
420  </list>
421</t>
422
423<section title="Content Coding Registry" anchor="content.coding.registry">
424<t>
425   The HTTP Content Coding Registry defines the name space for the content
426   coding names.
427</t>
428<t>
429   Registrations &MUST; include the following fields:
430   <list style="symbols">
431     <t>Name</t>
432     <t>Description</t>
433     <t>Pointer to specification text</t>
434   </list>
435</t>
436<t>
437   Names of content codings &MUST-NOT; overlap with names of transfer codings
438   (&transfer-codings;), unless the encoding transformation is identical (as it
439   is the case for the compression codings defined in
440   &compression-codings;).
441</t>
442<t>
443   Values to be added to this name space require a specification
444   (see "Specification Required" in
445   <xref target="RFC5226" x:fmt="of" x:sec="4.1"/>), and &MUST;
446   conform to the purpose of content coding defined in this section.
447</t>
448<t>
449   The registry itself is maintained at
450   <eref target="http://www.iana.org/assignments/http-parameters"/>.
451</t>
452</section>
453
454</section>
455
456<section title="Media Types" anchor="media.types">
457  <x:anchor-alias value="media-type"/>
458  <x:anchor-alias value="type"/>
459  <x:anchor-alias value="subtype"/>
460<t>
461   HTTP uses Internet Media Types <xref target="RFC2046"/> in the Content-Type (<xref target="header.content-type"/>)
462   and Accept (<xref target="header.accept"/>) header fields in order to provide
463   open and extensible data typing and type negotiation.
464</t>
465<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="media-type"/><iref primary="true" item="Grammar" subitem="type"/><iref primary="true" item="Grammar" subitem="subtype"/>
466  <x:ref>media-type</x:ref> = <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> )
467  <x:ref>type</x:ref>       = <x:ref>token</x:ref>
468  <x:ref>subtype</x:ref>    = <x:ref>token</x:ref>
469</artwork></figure>
470<t anchor="rule.parameter">
471  <x:anchor-alias value="attribute"/>
472  <x:anchor-alias value="parameter"/>
473  <x:anchor-alias value="value"/>
474   The type/subtype &MAY; be followed by parameters in the form of
475   attribute/value pairs.
476</t>
477<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="parameter"/><iref primary="true" item="Grammar" subitem="attribute"/><iref primary="true" item="Grammar" subitem="value"/>
478  <x:ref>parameter</x:ref>      = <x:ref>attribute</x:ref> "=" <x:ref>value</x:ref>
479  <x:ref>attribute</x:ref>      = <x:ref>token</x:ref>
480  <x:ref>value</x:ref>          = <x:ref>word</x:ref>
481</artwork></figure>
482<t>
483   The type, subtype, and parameter attribute names are case-insensitive.
484   Parameter values might or might not be case-sensitive, depending on the
485   semantics of the parameter name.  The presence or absence of a parameter might
486   be significant to the processing of a media-type, depending on its
487   definition within the media type registry.
488</t>
489<t>
490   A parameter value that matches the <x:ref>token</x:ref> production can be
491   transmitted as either a token or within a quoted-string. The quoted and
492   unquoted values are equivalent.
493</t>
494<t>
495   Note that some older HTTP applications do not recognize media type
496   parameters. When sending data to older HTTP applications,
497   implementations &SHOULD; only use media type parameters when they are
498   required by that type/subtype definition.
499</t>
500<t>
501   Media-type values are registered with the Internet Assigned Number
502   Authority (IANA). The media type registration process is
503   outlined in <xref target="RFC4288"/>. Use of non-registered media types is
504   discouraged.
505</t>
506
507<section title="Canonicalization and Text Defaults" anchor="canonicalization.and.text.defaults">
508<t>
509   Internet media types are registered with a canonical form. A
510   representation transferred via HTTP messages &MUST; be in the
511   appropriate canonical form prior to its transmission except for
512   "text" types, as defined in the next paragraph.
513</t>
514<t>
515   When in canonical form, media subtypes of the "text" type use CRLF as
516   the text line break. HTTP relaxes this requirement and allows the
517   transport of text media with plain CR or LF alone representing a line
518   break when it is done consistently for an entire representation. HTTP
519   applications &MUST; accept CRLF, bare CR, and bare LF as indicating
520   a line break in text media received via HTTP. In
521   addition, if the text is in a character encoding that does not
522   use octets 13 and 10 for CR and LF respectively, as is the case for
523   some multi-byte character encodings, HTTP allows the use of whatever octet
524   sequences are defined by that character encoding to represent the
525   equivalent of CR and LF for line breaks. This flexibility regarding
526   line breaks applies only to text media in the payload body; a bare CR
527   or LF &MUST-NOT; be substituted for CRLF within any of the HTTP control
528   structures (such as header fields and multipart boundaries).
529</t>
530<t>
531   If a representation is encoded with a content-coding, the underlying
532   data &MUST; be in a form defined above prior to being encoded.
533</t>
534</section>
535
536<section title="Multipart Types" anchor="multipart.types">
537<t>
538   MIME provides for a number of "multipart" types &mdash; encapsulations of
539   one or more representations within a single message-body. All multipart
540   types share a common syntax, as defined in <xref target="RFC2046" x:sec="5.1.1" x:fmt="of"/>,
541   and &MUST; include a boundary parameter as part of the media type
542   value. The message body is itself a protocol element and &MUST;
543   therefore use only CRLF to represent line breaks between body-parts.
544</t>
545<t>
546   In general, HTTP treats a multipart message-body no differently than
547   any other media type: strictly as payload.  HTTP does not use the
548   multipart boundary as an indicator of message-body length.
549   <!-- jre: re-insert removed text pointing to caching? -->
550   In all other respects, an HTTP user agent &SHOULD; follow the same or similar
551   behavior as a MIME user agent would upon receipt of a multipart type.
552   The MIME header fields within each body-part of a multipart message-body
553   do not have any significance to HTTP beyond that defined by
554   their MIME semantics.
555</t>
556<t>
557   If an application receives an unrecognized multipart subtype, the
558   application &MUST; treat it as being equivalent to "multipart/mixed".
559</t>
560<x:note>
561  <t>
562    <x:h>Note:</x:h> The "multipart/form-data" type has been specifically defined
563    for carrying form data suitable for processing via the POST
564    request method, as described in <xref target="RFC2388"/>.
565  </t>
566</x:note>
567</section>
568</section>
569
570<section title="Language Tags" anchor="language.tags">
571  <x:anchor-alias value="language-tag"/>
572<t>
573   A language tag, as defined in <xref target="RFC5646"/>, identifies a
574   natural language spoken, written, or otherwise conveyed by human beings for
575   communication of information to other human beings. Computer languages are
576   explicitly excluded. HTTP uses language tags within the Accept-Language and
577   Content-Language fields.
578</t>
579<t>
580   In summary, a language tag is composed of one or more parts: A primary
581   language subtag followed by a possibly empty series of subtags:
582</t>
583<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="language-tag"/>
584  <x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in <xref target="RFC5646" x:sec="2.1"/>&gt;
585</artwork></figure>
586<t>
587   White space is not allowed within the tag and all tags are case-insensitive.
588   The name space of language subtags is administered by the IANA (see
589   <eref target="http://www.iana.org/assignments/language-subtag-registry"/>).
590</t>
591<figure>
592  <preamble>Example tags include:</preamble>
593<artwork type="example">
594  en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN
595</artwork>
596</figure>
597<t>
598   See <xref target="RFC5646"/> for further information.
599</t>
600</section>
601</section>
602
603<section title="Payload" anchor="payload">
604<t>
605   HTTP messages &MAY; transfer a payload if not otherwise restricted by
606   the request method or response status code.  The payload consists of
607   metadata, in the form of header fields, and data, in the form of the
608   sequence of octets in the message-body after any transfer-coding has
609   been decoded.
610</t>
611<iref item="payload"/>
612<t>   
613   A "<x:dfn>payload</x:dfn>" in HTTP is always a partial or complete
614   representation of some resource.  We use separate terms for payload
615   and representation because some messages contain only the associated
616   representation's header fields (e.g., responses to HEAD) or only some
617   part(s) of the representation (e.g., the 206 status code).
618</t>
619<section title="Payload Header Fields" anchor="payload.header.fields">
620  <x:anchor-alias value="payload-header"/>
621<t>
622   HTTP header fields that specifically define the payload, rather than the
623   associated representation, are referred to as "payload header fields".
624   The following payload header fields are defined by HTTP/1.1:
625</t>
626<texttable align="left">
627  <ttcol>Header Field Name</ttcol>
628  <ttcol>Defined in...</ttcol>
629
630  <c>Content-Length</c> <c>&header-content-length;</c>
631  <c>Content-Range</c> <c>&header-content-range;</c>
632</texttable>
633</section>
634
635<section title="Payload Body" anchor="payload.body">
636  <x:anchor-alias value="payload-body"/>
637<t>
638   A payload body is only present in a message when a message-body is
639   present, as described in &message-body;. The payload body is obtained
640   from the message-body by decoding any Transfer-Encoding that might
641   have been applied to ensure safe and proper transfer of the message.
642</t>
643</section>
644</section>
645
646<section title="Representation" anchor="representation">
647<iref item="representation"/>
648<t>
649   A "<x:dfn>representation</x:dfn>" is information in a format that can be readily
650   communicated from one party to another.  A resource representation
651   is information that reflects the state of that resource, as observed
652   at some point in the past (e.g., in a response to GET) or to be
653   desired at some point in the future (e.g., in a PUT request).
654</t>
655<t>
656   Most, but not all, representations transferred via HTTP are intended
657   to be a representation of the target resource (the resource identified
658   by the effective request URI).  The precise semantics of a representation
659   are determined by the type of message (request or response), the request
660   method, the response status code, and the representation metadata.
661   For example, the above semantic is true for the representation in any
662   200 (OK) response to GET and for the representation in any PUT request.
663   A 200 response to PUT, in contrast, contains either a representation
664   that describes the successful action or a representation of the target
665   resource, with the latter indicated by a Content-Location header field
666   with the same value as the effective request URI.  Likewise, response
667   messages with an error status code usually contain a representation that
668   describes the error and what next steps are suggested for resolving it.
669</t>
670
671<section title="Representation Header Fields" anchor="representation.header.fields">
672  <x:anchor-alias value="representation-header"/>
673<t>
674   Representation header fields define metadata about the representation data
675   enclosed in the message-body or, if no message-body is present, about
676   the representation that would have been transferred in a 200 response
677   to a simultaneous GET request with the same effective request URI.
678</t>
679<t>
680   The following header fields are defined as representation metadata:
681</t>
682<texttable align="left">
683  <ttcol>Header Field Name</ttcol>
684  <ttcol>Defined in...</ttcol>
685
686  <c>Content-Encoding</c> <c><xref target="header.content-encoding"/></c>
687  <c>Content-Language</c> <c><xref target="header.content-language"/></c>
688  <c>Content-Location</c> <c><xref target="header.content-location"/></c>
689  <c>Content-Type</c> <c><xref target="header.content-type"/></c>
690  <c>Expires</c> <c>&header-expires;</c>
691  <c>Last-Modified</c> <c>&header-last-modified;</c>
692</texttable>
693</section>
694
695<section title="Representation Data" anchor="representation.data">
696  <x:anchor-alias value="representation-data"/>
697<t>
698   The representation body associated with an HTTP message is
699   either provided as the payload body of the message or
700   referred to by the message semantics and the effective request
701   URI.  The representation data is in a format and encoding defined by
702   the representation metadata header fields.
703</t>
704<t>
705   The data type of the representation data
706   is determined via the header fields Content-Type and Content-Encoding.
707   These define a two-layer, ordered encoding model:
708</t>
709<figure><artwork type="example">
710  representation-data := Content-Encoding( Content-Type( bits ) )
711</artwork></figure>
712<t>
713   Content-Type specifies the media type of the underlying data, which
714   defines both the data format and how that data &SHOULD; be processed
715   by the recipient (within the scope of the request method semantics).
716   Any HTTP/1.1 message containing a payload body &SHOULD; include a
717   Content-Type header field defining the media type of the associated
718   representation unless that metadata is unknown to the sender.
719   If the Content-Type header field is not present, it indicates that
720   the sender does not know the media type of the representation;
721   recipients &MAY; either assume that the media type is
722   "application/octet-stream" (<xref target="RFC2046" x:fmt="," x:sec="4.5.1"/>)
723   or examine the content to determine its type.
724</t>
725<t>
726   In practice, resource owners do not always properly configure their origin
727   server to provide the correct Content-Type for a given representation,
728   with the result that some clients will examine a response body's content
729   and override the specified type.
730   Clients that do so risk drawing incorrect conclusions, which might expose
731   additional security risks (e.g., "privilege escalation").  Furthermore,
732   it is impossible to determine the sender's intent by examining the data
733   format: many data formats match multiple media types that differ only in
734   processing semantics.  Implementers are encouraged to provide a means of
735   disabling such "content sniffing" when it is used.
736</t>
737<t>
738   Content-Encoding is used to indicate any additional content
739   codings applied to the data, usually for the purpose of data
740   compression, that are a property of the representation.  If
741   Content-Encoding is not present, then there is no additional
742   encoding beyond that defined by the Content-Type.
743</t>
744</section>
745</section>
746
747<section title="Content Negotiation" anchor="content.negotiation">
748<t>
749   HTTP responses include a representation which contains information for
750   interpretation, whether by a human user or for further processing.
751   Often, the server has different ways of representing the
752   same information; for example, in different formats, languages,
753   or using different character encodings.
754</t>
755<t>
756   HTTP clients and their users might have different or variable
757   capabilities, characteristics or preferences which would influence
758   which representation, among those available from the server,
759   would be best for the server to deliver. For this reason, HTTP
760   provides mechanisms for "content negotiation" &mdash; a process of
761   allowing selection of a representation of a given resource,
762   when more than one is available.
763</t>
764<t>
765   This specification defines two patterns of content negotiation;
766   "server-driven", where the server selects the representation based
767   upon the client's stated preferences, and "agent-driven" negotiation,
768   where the server provides a list of representations for the client to
769   choose from, based upon their metadata. In addition,  there are
770   other patterns: some applications use an "active content" pattern,
771   where the server returns active content which runs on the client
772   and, based on client available parameters, selects additional
773   resources to invoke. "Transparent Content Negotiation" (<xref target="RFC2295"/>)
774   has also been proposed.
775</t>
776<t>
777   These patterns are all widely used, and have trade-offs in applicability
778   and practicality. In particular, when the number of preferences or
779   capabilities to be expressed by a client are large (such as when many
780   different formats are supported by a user-agent), server-driven
781   negotiation becomes unwieldy, and might not be appropriate. Conversely,
782   when the number of representations to choose from is very large,
783   agent-driven negotiation might not be appropriate.
784</t>
785<t>
786   Note that in all cases, the supplier of representations has the
787   responsibility for determining which representations might be
788   considered to be the "same information".
789</t>
790
791<section title="Server-driven Negotiation" anchor="server-driven.negotiation">
792<t>
793   If the selection of the best representation for a response is made by
794   an algorithm located at the server, it is called server-driven
795   negotiation. Selection is based on the available representations of
796   the response (the dimensions over which it can vary; e.g., language,
797   content-coding, etc.) and the contents of particular header fields in
798   the request message or on other information pertaining to the request
799   (such as the network address of the client).
800</t>
801<t>
802   Server-driven negotiation is advantageous when the algorithm for
803   selecting from among the available representations is difficult to
804   describe to the user agent, or when the server desires to send its
805   "best guess" to the client along with the first response (hoping to
806   avoid the round-trip delay of a subsequent request if the "best
807   guess" is good enough for the user). In order to improve the server's
808   guess, the user agent &MAY; include request header fields (Accept,
809   Accept-Language, Accept-Encoding, etc.) which describe its
810   preferences for such a response.
811</t>
812<t>
813   Server-driven negotiation has disadvantages:
814  <list style="numbers">
815    <t>
816         It is impossible for the server to accurately determine what
817         might be "best" for any given user, since that would require
818         complete knowledge of both the capabilities of the user agent
819         and the intended use for the response (e.g., does the user want
820         to view it on screen or print it on paper?).
821    </t>
822    <t>
823         Having the user agent describe its capabilities in every
824         request can be both very inefficient (given that only a small
825         percentage of responses have multiple representations) and a
826         potential violation of the user's privacy.
827    </t>
828    <t>
829         It complicates the implementation of an origin server and the
830         algorithms for generating responses to a request.
831    </t>
832    <t>
833         It might limit a public cache's ability to use the same response
834         for multiple user's requests.
835    </t>
836  </list>
837</t>
838<t>
839   Server-driven negotiation allows the user agent to specify its preferences,
840   but it cannot expect responses to always honour them. For example, the origin
841   server might not implement server-driven negotiation, or it might decide that
842   sending a response that doesn't conform to them is better than sending a 406
843   (Not Acceptable) response.
844</t>
845<t>
846   Many of the mechanisms for expressing preferences use quality values to
847   declare relative preference. See &qvalue; for more information.
848</t>
849<t>
850   HTTP/1.1 includes the following header fields for enabling
851   server-driven negotiation through description of user agent
852   capabilities and user preferences: Accept (<xref target="header.accept"/>), Accept-Charset
853   (<xref target="header.accept-charset"/>), Accept-Encoding (<xref target="header.accept-encoding"/>), Accept-Language
854   (<xref target="header.accept-language"/>), and User-Agent (&header-user-agent;).
855   However, an origin server is not limited to these dimensions and &MAY; vary
856   the response based on any aspect of the request, including aspects
857   of the connection (e.g., IP address) or information within extension
858   header fields not defined by this specification.
859</t>
860<x:note>
861  <t>
862    <x:h>Note:</x:h> In practice, User-Agent based negotiation is fragile,
863    because new clients might not be recognized.
864  </t>
865</x:note>
866<t>
867   The Vary header field (&header-vary;) can be used to express the parameters the
868   server uses to select a representation that is subject to server-driven
869   negotiation.
870</t>
871</section>
872
873<section title="Agent-driven Negotiation" anchor="agent-driven.negotiation">
874<t>
875   With agent-driven negotiation, selection of the best representation
876   for a response is performed by the user agent after receiving an
877   initial response from the origin server. Selection is based on a list
878   of the available representations of the response included within the
879   header fields or body of the initial response, with each
880   representation identified by its own URI. Selection from among the
881   representations can be performed automatically (if the user agent is
882   capable of doing so) or manually by the user selecting from a
883   generated (possibly hypertext) menu.
884</t>
885<t>
886   Agent-driven negotiation is advantageous when the response would vary
887   over commonly-used dimensions (such as type, language, or encoding),
888   when the origin server is unable to determine a user agent's
889   capabilities from examining the request, and generally when public
890   caches are used to distribute server load and reduce network usage.
891</t>
892<t>
893   Agent-driven negotiation suffers from the disadvantage of needing a
894   second request to obtain the best alternate representation. This
895   second request is only efficient when caching is used. In addition,
896   this specification does not define any mechanism for supporting
897   automatic selection, though it also does not prevent any such
898   mechanism from being developed as an extension and used within
899   HTTP/1.1.
900</t>
901<t>
902   This specification defines the 300 (Multiple Choices) and 406 (Not Acceptable)
903   status codes for enabling agent-driven negotiation when the server is
904   unwilling or unable to provide a varying response using server-driven
905   negotiation.
906</t>
907</section>
908</section>
909
910<section title="Header Field Definitions" anchor="header.field.definitions">
911<t>
912   This section defines the syntax and semantics of HTTP/1.1 header fields
913   related to the payload of messages.
914</t>
915
916<section title="Accept" anchor="header.accept">
917  <iref primary="true" item="Accept header field" x:for-anchor=""/>
918  <iref primary="true" item="Header Fields" subitem="Accept" x:for-anchor=""/>
919  <x:anchor-alias value="Accept"/>
920  <x:anchor-alias value="accept-ext"/>
921  <x:anchor-alias value="accept-params"/>
922  <x:anchor-alias value="media-range"/>
923<t>
924   The "Accept" header field can be used by user agents to specify
925   response media types that are acceptable. Accept header fields can be used to
926   indicate that the request is specifically limited to a small set of desired
927   types, as in the case of a request for an in-line image.
928</t>
929<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept"/><iref primary="true" item="Grammar" subitem="media-range"/><iref primary="true" item="Grammar" subitem="accept-params"/><iref primary="true" item="Grammar" subitem="accept-ext"/>
930  <x:ref>Accept</x:ref> = #( <x:ref>media-range</x:ref> [ <x:ref>accept-params</x:ref> ] )
931 
932  <x:ref>media-range</x:ref>    = ( "*/*"
933                   / ( <x:ref>type</x:ref> "/" "*" )
934                   / ( <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> )
935                   ) *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> )
936  <x:ref>accept-params</x:ref>  = <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> *( <x:ref>accept-ext</x:ref> )
937  <x:ref>accept-ext</x:ref>     = <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>token</x:ref> [ "=" <x:ref>word</x:ref> ]
938</artwork></figure>
939<t>
940   The asterisk "*" character is used to group media types into ranges,
941   with "*/*" indicating all media types and "type/*" indicating all
942   subtypes of that type. The media-range &MAY; include media type
943   parameters that are applicable to that range.
944</t>
945<t>
946   Each media-range &MAY; be followed by one or more accept-params,
947   beginning with the "q" parameter for indicating a relative quality
948   factor. The first "q" parameter (if any) separates the media-range
949   parameter(s) from the accept-params. Quality factors allow the user
950   or user agent to indicate the relative degree of preference for that
951   media-range, using the qvalue scale from 0 to 1 (&qvalue;). The
952   default value is q=1.
953</t>
954<x:note>
955  <t>
956    <x:h>Note:</x:h> Use of the "q" parameter name to separate media type
957    parameters from Accept extension parameters is due to historical
958    practice. Although this prevents any media type parameter named
959    "q" from being used with a media range, such an event is believed
960    to be unlikely given the lack of any "q" parameters in the IANA
961    media type registry and the rare usage of any media type
962    parameters in Accept. Future media types are discouraged from
963    registering any parameter named "q".
964  </t>
965</x:note>
966<t>
967   The example
968</t>
969<figure><artwork type="example">
970  Accept: audio/*; q=0.2, audio/basic
971</artwork></figure>
972<t>
973   &SHOULD; be interpreted as "I prefer audio/basic, but send me any audio
974   type if it is the best available after an 80% mark-down in quality".
975</t>
976<t>
977   A request without any Accept header field implies that the user agent
978   will accept any media type in response.
979   If an Accept header field is present in a request and none of the
980   available representations for the response have a media type that is
981   listed as acceptable, the origin server &MAY; either
982   honor the Accept header field by sending a 406 (Not Acceptable) response
983   or disregard the Accept header field by treating the response as if
984   it is not subject to content negotiation.
985</t>
986<t>
987   A more elaborate example is
988</t>
989<figure><artwork type="example">
990  Accept: text/plain; q=0.5, text/html,
991          text/x-dvi; q=0.8, text/x-c
992</artwork></figure>
993<t>
994   Verbally, this would be interpreted as "text/html and text/x-c are
995   the preferred media types, but if they do not exist, then send the
996   text/x-dvi representation, and if that does not exist, send the text/plain
997   representation".
998</t>
999<t>
1000   Media ranges can be overridden by more specific media ranges or
1001   specific media types. If more than one media range applies to a given
1002   type, the most specific reference has precedence. For example,
1003</t>
1004<figure><artwork type="example">
1005  Accept: text/*, text/plain, text/plain;format=flowed, */*
1006</artwork></figure>
1007<t>
1008   have the following precedence:
1009   <list style="numbers">
1010    <t>text/plain;format=flowed</t>
1011    <t>text/plain</t>
1012    <t>text/*</t>
1013    <t>*/*</t>
1014   </list>
1015</t>
1016<t>
1017   The media type quality factor associated with a given type is
1018   determined by finding the media range with the highest precedence
1019   which matches that type. For example,
1020</t>
1021<figure><artwork type="example">
1022  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
1023          text/html;level=2;q=0.4, */*;q=0.5
1024</artwork></figure>
1025<t>
1026   would cause the following values to be associated:
1027</t>
1028<texttable align="left">
1029  <ttcol>Media Type</ttcol><ttcol>Quality Value</ttcol>
1030  <c>text/html;level=1</c>    <c>1</c>
1031  <c>text/html</c>            <c>0.7</c>
1032  <c>text/plain</c>           <c>0.3</c>
1033  <c>image/jpeg</c>           <c>0.5</c>
1034  <c>text/html;level=2</c>    <c>0.4</c>
1035  <c>text/html;level=3</c>    <c>0.7</c>
1036</texttable>
1037<t>
1038      <x:h>Note:</x:h> A user agent might be provided with a default set of quality
1039      values for certain media ranges. However, unless the user agent is
1040      a closed system which cannot interact with other rendering agents,
1041      this default set ought to be configurable by the user.
1042</t>
1043</section>
1044
1045<section title="Accept-Charset" anchor="header.accept-charset">
1046  <iref primary="true" item="Accept-Charset header field" x:for-anchor=""/>
1047  <iref primary="true" item="Header Fields" subitem="Accept-Charset" x:for-anchor=""/>
1048  <x:anchor-alias value="Accept-Charset"/>
1049<t>
1050   The "Accept-Charset" header field can be used by user agents to
1051   indicate what character encodings are acceptable in a response
1052   payload. This field allows
1053   clients capable of understanding more comprehensive or special-purpose
1054   character encodings to signal that capability to a server which is capable of
1055   representing documents in those character encodings.
1056</t>
1057<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Charset"/>
1058  <x:ref>Accept-Charset</x:ref> = 1#( ( <x:ref>charset</x:ref> / "*" )
1059                         [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1060</artwork></figure>
1061<t>
1062   Character encoding values (a.k.a., charsets) are described in
1063   <xref target="character.sets"/>. Each charset &MAY; be given an
1064   associated quality value which represents the user's preference
1065   for that charset. The default value is q=1. An example is
1066</t>
1067<figure><artwork type="example">
1068  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
1069</artwork></figure>
1070<t>
1071   The special value "*", if present in the Accept-Charset field,
1072   matches every character encoding which is not mentioned elsewhere in the
1073   Accept-Charset field. If no "*" is present in an Accept-Charset field, then
1074   all character encodings not explicitly mentioned get a quality value of 0.
1075</t>
1076<t>
1077   A request without any Accept-Charset header field implies that the user
1078   agent will accept any character encoding in response.
1079   If an Accept-Charset header field is present in a request and none of the
1080   available representations for the response have a character encoding that
1081   is listed as acceptable, the origin server &MAY; either honor the
1082   Accept-Charset header field by sending a 406 (Not Acceptable) response or
1083   disregard the Accept-Charset header field by treating the response as if
1084   it is not subject to content negotiation.
1085</t>
1086</section>
1087
1088<section title="Accept-Encoding" anchor="header.accept-encoding">
1089  <iref primary="true" item="Accept-Encoding header field" x:for-anchor=""/>
1090  <iref primary="true" item="Header Fields" subitem="Accept-Encoding" x:for-anchor=""/>
1091  <x:anchor-alias value="Accept-Encoding"/>
1092  <x:anchor-alias value="codings"/>
1093<t>
1094   The "Accept-Encoding" header field can be used by user agents to
1095   indicate what response content-codings (<xref target="content.codings"/>)
1096   are acceptable in the response.  An "identity" token is used as a synonym
1097   for "no encoding" in order to communicate when no encoding is preferred.
1098</t>
1099<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Encoding"/><iref primary="true" item="Grammar" subitem="codings"/>
1100  <x:ref>Accept-Encoding</x:ref>  = #( <x:ref>codings</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1101  <x:ref>codings</x:ref>          = <x:ref>content-coding</x:ref> / "identity" / "*"
1102</artwork></figure>
1103<t>
1104   Each codings value &MAY; be given an associated quality value which
1105   represents the preference for that encoding. The default value is q=1.
1106</t>
1107<t>
1108   For example,
1109</t>
1110<figure><artwork type="example">
1111  Accept-Encoding: compress, gzip
1112  Accept-Encoding:
1113  Accept-Encoding: *
1114  Accept-Encoding: compress;q=0.5, gzip;q=1.0
1115  Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
1116</artwork></figure>
1117<t>
1118   A server tests whether a content-coding for a given representation is
1119   acceptable, according to an Accept-Encoding field, using these rules:
1120  <list style="numbers">
1121      <t>The special "*" symbol in an Accept-Encoding field matches any
1122         available content-coding not explicitly listed in the header
1123         field.</t>
1124
1125      <t>If the representation has no content-coding, then it is acceptable
1126         by default unless specifically excluded by the Accept-Encoding field
1127         stating either "identity;q=0" or "*;q=0" without a more specific
1128         entry for "identity".</t>
1129
1130      <t>If the representation's content-coding is one of the content-codings
1131         listed in the Accept-Encoding field, then it is acceptable unless
1132         it is accompanied by a qvalue of 0. (As defined in &qvalue;, a
1133         qvalue of 0 means "not acceptable".)</t>
1134
1135      <t>If multiple content-codings are acceptable, then the acceptable
1136         content-coding with the highest non-zero qvalue is preferred.</t>
1137  </list>
1138</t>
1139<t>
1140   An Accept-Encoding header field with a combined field-value that is empty
1141   implies that the user agent does not want any content-coding in response.
1142   If an Accept-Encoding header field is present in a request and none of the
1143   available representations for the response have a content-coding that
1144   is listed as acceptable, the origin server &SHOULD; send a response
1145   without any content-coding.
1146</t>
1147<t>
1148   A request without an Accept-Encoding header field implies that the user
1149   agent will accept any content-coding in response, but a representation
1150   without content-coding is preferred for compatibility with the widest
1151   variety of user agents.
1152</t>
1153<x:note>
1154  <t>
1155    <x:h>Note:</x:h> Most HTTP/1.0 applications do not recognize or obey qvalues
1156    associated with content-codings. This means that qvalues will not
1157    work and are not permitted with x-gzip or x-compress.
1158  </t>
1159</x:note>
1160</section>
1161
1162<section title="Accept-Language" anchor="header.accept-language">
1163  <iref primary="true" item="Accept-Language header field" x:for-anchor=""/>
1164  <iref primary="true" item="Header Fields" subitem="Accept-Language" x:for-anchor=""/>
1165  <x:anchor-alias value="Accept-Language"/>
1166  <x:anchor-alias value="language-range"/>
1167<t>
1168   The "Accept-Language" header field can be used by user agents to
1169   indicate the set of natural languages that are preferred in the response.
1170   Language tags are defined in <xref target="language.tags"/>.
1171</t>
1172<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Language"/><iref primary="true" item="Grammar" subitem="language-range"/>
1173  <x:ref>Accept-Language</x:ref> =
1174                    1#( <x:ref>language-range</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1175  <x:ref>language-range</x:ref>  =
1176            &lt;language-range, defined in <xref target="RFC4647" x:fmt="," x:sec="2.1"/>&gt;
1177</artwork></figure>
1178<t>
1179   Each language-range can be given an associated quality value which
1180   represents an estimate of the user's preference for the languages
1181   specified by that range. The quality value defaults to "q=1". For
1182   example,
1183</t>
1184<figure><artwork type="example">
1185  Accept-Language: da, en-gb;q=0.8, en;q=0.7
1186</artwork></figure>
1187<t>
1188   would mean: "I prefer Danish, but will accept British English and
1189   other types of English".
1190   (see also <xref target="RFC4647" x:sec="2.3" x:fmt="of"/>)
1191</t>
1192<t>
1193   For matching, <xref target="RFC4647" x:sec="3" x:fmt="of"/> defines
1194   several matching schemes. Implementations can offer the most appropriate
1195   matching scheme for their requirements.
1196</t>
1197<x:note>
1198  <t>
1199    <x:h>Note:</x:h> The "Basic Filtering" scheme (<xref target="RFC4647"
1200    x:fmt="," x:sec="3.3.1"/>) is identical to the matching scheme that was
1201    previously defined in <xref target="RFC2616" x:fmt="of" x:sec="14.4"/>.
1202  </t>
1203</x:note>
1204<t>
1205   It might be contrary to the privacy expectations of the user to send
1206   an Accept-Language header field with the complete linguistic preferences of
1207   the user in every request. For a discussion of this issue, see
1208   <xref target="privacy.issues.connected.to.accept.header.fields"/>.
1209</t>
1210<t>
1211   As intelligibility is highly dependent on the individual user, it is
1212   recommended that client applications make the choice of linguistic
1213   preference available to the user. If the choice is not made
1214   available, then the Accept-Language header field &MUST-NOT; be given in
1215   the request.
1216</t>
1217<x:note>
1218  <t>
1219    <x:h>Note:</x:h> When making the choice of linguistic preference available to
1220    the user, we remind implementors of  the fact that users are not
1221    familiar with the details of language matching as described above,
1222    and ought to be provided appropriate guidance. As an example, users
1223    might assume that on selecting "en-gb", they will be served any
1224    kind of English document if British English is not available. A
1225    user agent might suggest in such a case to add "en" to get the
1226    best matching behavior.
1227  </t>
1228</x:note>
1229</section>
1230
1231<section title="Content-Encoding" anchor="header.content-encoding">
1232  <iref primary="true" item="Content-Encoding header field" x:for-anchor=""/>
1233  <iref primary="true" item="Header Fields" subitem="Content-Encoding" x:for-anchor=""/>
1234  <x:anchor-alias value="Content-Encoding"/>
1235<t>
1236   The "Content-Encoding" header field indicates what content-codings
1237   have been applied to the representation beyond those inherent in the media
1238   type, and thus what decoding mechanisms must be applied in order to obtain
1239   the media-type referenced by the Content-Type header field.
1240   Content-Encoding is primarily used to allow a representation to be
1241   compressed without losing the identity of its underlying media type.
1242</t>
1243<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Encoding"/>
1244  <x:ref>Content-Encoding</x:ref> = 1#<x:ref>content-coding</x:ref>
1245</artwork></figure>
1246<t>
1247   Content codings are defined in <xref target="content.codings"/>. An example of its use is
1248</t>
1249<figure><artwork type="example">
1250  Content-Encoding: gzip
1251</artwork></figure>
1252<t>
1253   The content-coding is a characteristic of the representation.
1254   Typically, the representation body is stored with this
1255   encoding and is only decoded before rendering or analogous usage.
1256   However, a transforming proxy &MAY; modify the content-coding if the
1257   new coding is known to be acceptable to the recipient, unless the
1258   "no-transform" cache-control directive is present in the message.
1259</t>
1260<t>
1261   If the media type includes an inherent encoding, such as a data format
1262   that is always compressed, then that encoding would not be restated as
1263   a Content-Encoding even if it happens to be the same algorithm as one
1264   of the content-codings.  Such a content-coding would only be listed if,
1265   for some bizarre reason, it is applied a second time to form the
1266   representation.  Likewise, an origin server might choose to publish the
1267   same payload data as multiple representations that differ only in whether
1268   the coding is defined as part of Content-Type or Content-Encoding, since
1269   some user agents will behave differently in their handling of each
1270   response (e.g., open a "Save as ..." dialog instead of automatic
1271   decompression and rendering of content).
1272</t>
1273<t>
1274   A representation that has a content-coding applied to it &MUST; include
1275   a Content-Encoding header field (<xref target="header.content-encoding"/>)
1276   that lists the content-coding(s) applied.
1277</t>
1278<t>
1279   If multiple encodings have been applied to a representation, the content
1280   codings &MUST; be listed in the order in which they were applied.
1281   Additional information about the encoding parameters &MAY; be provided
1282   by other header fields not defined by this specification.
1283</t>
1284<t>
1285   If the content-coding of a representation in a request message is not
1286   acceptable to the origin server, the server &SHOULD; respond with a
1287   status code of 415 (Unsupported Media Type).
1288</t>
1289</section>
1290
1291<section title="Content-Language" anchor="header.content-language">
1292  <iref primary="true" item="Content-Language header field" x:for-anchor=""/>
1293  <iref primary="true" item="Header Fields" subitem="Content-Language" x:for-anchor=""/>
1294  <x:anchor-alias value="Content-Language"/>
1295<t>
1296   The "Content-Language" header field describes the natural
1297   language(s) of the intended audience for the representation. Note that this might
1298   not be equivalent to all the languages used within the representation.
1299</t>
1300<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Language"/>
1301  <x:ref>Content-Language</x:ref> = 1#<x:ref>language-tag</x:ref>
1302</artwork></figure>
1303<t>
1304   Language tags are defined in <xref target="language.tags"/>. The primary purpose of
1305   Content-Language is to allow a user to identify and differentiate
1306   representations according to the user's own preferred language. Thus, if the
1307   body content is intended only for a Danish-literate audience, the
1308   appropriate field is
1309</t>
1310<figure><artwork type="example">
1311  Content-Language: da
1312</artwork></figure>
1313<t>
1314   If no Content-Language is specified, the default is that the content
1315   is intended for all language audiences. This might mean that the
1316   sender does not consider it to be specific to any natural language,
1317   or that the sender does not know for which language it is intended.
1318</t>
1319<t>
1320   Multiple languages &MAY; be listed for content that is intended for
1321   multiple audiences. For example, a rendition of the "Treaty of
1322   Waitangi", presented simultaneously in the original Maori and English
1323   versions, would call for
1324</t>
1325<figure><artwork type="example">
1326  Content-Language: mi, en
1327</artwork></figure>
1328<t>
1329   However, just because multiple languages are present within a representation
1330   does not mean that it is intended for multiple linguistic audiences.
1331   An example would be a beginner's language primer, such as "A First
1332   Lesson in Latin", which is clearly intended to be used by an
1333   English-literate audience. In this case, the Content-Language would
1334   properly only include "en".
1335</t>
1336<t>
1337   Content-Language &MAY; be applied to any media type &mdash; it is not
1338   limited to textual documents.
1339</t>
1340</section>
1341
1342<section title="Content-Location" anchor="header.content-location">
1343  <iref primary="true" item="Content-Location header field" x:for-anchor=""/>
1344  <iref primary="true" item="Header Fields" subitem="Content-Location" x:for-anchor=""/>
1345  <x:anchor-alias value="Content-Location"/>
1346<t>
1347   The "Content-Location" header field supplies a URI that can be used
1348   as a specific identifier for the representation in this message.
1349   In other words, if one were to perform a GET on this URI at the time
1350   of this message's generation, then a 200 response would contain the
1351   same representation that is enclosed as payload in this message.
1352</t>
1353<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Location"/>
1354  <x:ref>Content-Location</x:ref> = <x:ref>absolute-URI</x:ref> / <x:ref>partial-URI</x:ref>
1355</artwork></figure>
1356<t>
1357   The Content-Location value is not a replacement for the effective
1358   Request URI (&effective-request-uri;).  It is representation metadata.
1359   It has the same syntax and semantics as the header field of the same name
1360   defined for MIME body parts in <xref target="RFC2557" x:fmt="of" x:sec="4"/>.
1361   However, its appearance in an HTTP message has some special implications
1362   for HTTP recipients.
1363</t>
1364<t>
1365   If Content-Location is included in a response message and its value
1366   is the same as the effective request URI, then the response payload
1367   &SHOULD; be considered the current representation of that resource.
1368   For a GET or HEAD request, this is the same as the default semantics
1369   when no Content-Location is provided by the server.  For a state-changing
1370   request like PUT or POST, it implies that the server's response contains
1371   the new representation of that resource, thereby distinguishing it from
1372   representations that might only report about the action (e.g., "It worked!").
1373   This allows authoring applications to update their local copies without
1374   the need for a subsequent GET request.
1375</t>
1376<t>
1377   If Content-Location is included in a response message and its value
1378   differs from the effective request URI, then the origin server is
1379   informing recipients that this representation has its own, presumably
1380   more specific, identifier.  For a GET or HEAD request, this is an
1381   indication that the effective request URI identifies a resource that
1382   is subject to content negotiation and the representation selected for
1383   this response can also be found at the identified URI.  For other
1384   methods, such a Content-Location indicates that this representation
1385   contains a report on the action's status and the same report is
1386   available (for future access with GET) at the given URI.  For
1387   example, a purchase transaction made via a POST request might
1388   include a receipt document as the payload of the 200 response;
1389   the Content-Location value provides an identifier for retrieving
1390   a copy of that same receipt in the future.
1391</t>
1392<t>
1393   If Content-Location is included in a request message, then it &MAY;
1394   be interpreted by the origin server as an indication of where the
1395   user agent originally obtained the content of the enclosed
1396   representation (prior to any subsequent modification of the content
1397   by that user agent).  In other words, the user agent is providing
1398   the same representation metadata that it received with the original
1399   representation.  However, such interpretation &MUST-NOT; be used to
1400   alter the semantics of the method requested by the client.  For
1401   example, if a client makes a PUT request on a negotiated resource
1402   and the origin server accepts that PUT (without redirection), then the
1403   new set of values for that resource is expected to be consistent with
1404   the one representation supplied in that PUT; the Content-Location
1405   cannot be used as a form of reverse content selection that
1406   identifies only one of the negotiated representations to be updated.
1407   If the user agent had wanted the latter semantics, it would have applied
1408   the PUT directly to the Content-Location URI.
1409</t>
1410<t>
1411   A Content-Location field received in a request message is transitory
1412   information that &SHOULD-NOT; be saved with other representation
1413   metadata for use in later responses.  The Content-Location's value
1414   might be saved for use in other contexts, such as within source links
1415   or other metadata.
1416</t>
1417<t>
1418   A cache cannot assume that a representation with a Content-Location
1419   different from the URI used to retrieve it can be used to respond to
1420   later requests on that Content-Location URI.
1421</t>
1422<t>
1423   If the Content-Location value is a partial URI, the partial URI is
1424   interpreted relative to the effective request URI.
1425</t>
1426</section>
1427
1428<section title="Content-Type" anchor="header.content-type">
1429  <iref primary="true" item="Content-Type header field" x:for-anchor=""/>
1430  <iref primary="true" item="Header Fields" subitem="Content-Type" x:for-anchor=""/>
1431  <x:anchor-alias value="Content-Type"/>
1432<t>
1433   The "Content-Type" header field indicates the media type of the
1434   representation. In the case of responses to the HEAD method, the media type is
1435   that which would have been sent had the request been a GET.
1436</t>
1437<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Type"/>
1438  <x:ref>Content-Type</x:ref> = <x:ref>media-type</x:ref>
1439</artwork></figure>
1440<t>
1441   Media types are defined in <xref target="media.types"/>. An example of the field is
1442</t>
1443<figure><artwork type="example">
1444  Content-Type: text/html; charset=ISO-8859-4
1445</artwork></figure>
1446<t>
1447   Further discussion of Content-Type is provided in <xref target="representation.data"/>.
1448</t>
1449</section>
1450
1451</section>
1452
1453<section title="IANA Considerations" anchor="IANA.considerations">
1454<section title="Header Field Registration" anchor="header.field.registration">
1455<t>
1456   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
1457   with the permanent registrations below (see <xref target="RFC3864"/>):
1458</t>
1459<?BEGININC p3-payload.iana-headers ?>
1460<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
1461<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
1462   <ttcol>Header Field Name</ttcol>
1463   <ttcol>Protocol</ttcol>
1464   <ttcol>Status</ttcol>
1465   <ttcol>Reference</ttcol>
1466
1467   <c>Accept</c>
1468   <c>http</c>
1469   <c>standard</c>
1470   <c>
1471      <xref target="header.accept"/>
1472   </c>
1473   <c>Accept-Charset</c>
1474   <c>http</c>
1475   <c>standard</c>
1476   <c>
1477      <xref target="header.accept-charset"/>
1478   </c>
1479   <c>Accept-Encoding</c>
1480   <c>http</c>
1481   <c>standard</c>
1482   <c>
1483      <xref target="header.accept-encoding"/>
1484   </c>
1485   <c>Accept-Language</c>
1486   <c>http</c>
1487   <c>standard</c>
1488   <c>
1489      <xref target="header.accept-language"/>
1490   </c>
1491   <c>Content-Encoding</c>
1492   <c>http</c>
1493   <c>standard</c>
1494   <c>
1495      <xref target="header.content-encoding"/>
1496   </c>
1497   <c>Content-Language</c>
1498   <c>http</c>
1499   <c>standard</c>
1500   <c>
1501      <xref target="header.content-language"/>
1502   </c>
1503   <c>Content-Location</c>
1504   <c>http</c>
1505   <c>standard</c>
1506   <c>
1507      <xref target="header.content-location"/>
1508   </c>
1509   <c>Content-Type</c>
1510   <c>http</c>
1511   <c>standard</c>
1512   <c>
1513      <xref target="header.content-type"/>
1514   </c>
1515   <c>MIME-Version</c>
1516   <c>http</c>
1517   <c>standard</c>
1518   <c>
1519      <xref target="mime-version"/>
1520   </c>
1521</texttable>
1522<!--(END)-->
1523<?ENDINC p3-payload.iana-headers ?>
1524<t>
1525   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
1526</t>
1527</section>
1528
1529<section title="Content Coding Registry" anchor="content.coding.registration">
1530<t>
1531   The registration procedure for HTTP Content Codings is now defined
1532   by <xref target="content.coding.registry"/> of this document.
1533</t>
1534<t>
1535   The HTTP Content Codings Registry located at <eref target="http://www.iana.org/assignments/http-parameters"/>
1536   shall be updated with the registration below:
1537</t>
1538<texttable align="left" suppress-title="true" anchor="iana.content.coding.registration.table">
1539   <ttcol>Name</ttcol>
1540   <ttcol>Description</ttcol>
1541   <ttcol>Reference</ttcol>
1542   <c>compress</c>
1543   <c>UNIX "compress" program method</c>
1544   <c>
1545      &compress-coding;
1546   </c>
1547   <c>deflate</c>
1548   <c>"deflate" compression mechanism (<xref target="RFC1951"/>) used inside
1549   the "zlib" data format (<xref target="RFC1950"/>)
1550   </c>
1551   <c>
1552      &deflate-coding;
1553   </c>
1554   <c>gzip</c>
1555   <c>Same as GNU zip <xref target="RFC1952"/></c>
1556   <c>
1557      &gzip-coding;
1558   </c>
1559   <c>identity</c>
1560   <c>reserved (synonym for "no encoding" in Accept-Encoding header field)</c>
1561   <c>
1562      <xref target="header.accept-encoding"/>
1563   </c>
1564</texttable>
1565</section>
1566
1567</section>
1568
1569<section title="Security Considerations" anchor="security.considerations">
1570<t>
1571   This section is meant to inform application developers, information
1572   providers, and users of the security limitations in HTTP/1.1 as
1573   described by this document. The discussion does not include
1574   definitive solutions to the problems revealed, though it does make
1575   some suggestions for reducing security risks.
1576</t>
1577
1578<section title="Privacy Issues Connected to Accept Header Fields" anchor="privacy.issues.connected.to.accept.header.fields">
1579<t>
1580   Accept headers fields can reveal information about the user to all
1581   servers which are accessed. The Accept-Language header field in particular
1582   can reveal information the user would consider to be of a private
1583   nature, because the understanding of particular languages is often
1584   strongly correlated to the membership of a particular ethnic group.
1585   User agents which offer the option to configure the contents of an
1586   Accept-Language header field to be sent in every request are strongly
1587   encouraged to let the configuration process include a message which
1588   makes the user aware of the loss of privacy involved.
1589</t>
1590<t>
1591   An approach that limits the loss of privacy would be for a user agent
1592   to omit the sending of Accept-Language header fields by default, and to ask
1593   the user whether or not to start sending Accept-Language header fields to a
1594   server if it detects, by looking for any Vary header fields
1595   generated by the server, that such sending could improve the quality
1596   of service.
1597</t>
1598<t>
1599   Elaborate user-customized accept header fields sent in every request,
1600   in particular if these include quality values, can be used by servers
1601   as relatively reliable and long-lived user identifiers. Such user
1602   identifiers would allow content providers to do click-trail tracking,
1603   and would allow collaborating content providers to match cross-server
1604   click-trails or form submissions of individual users. Note that for
1605   many users not behind a proxy, the network address of the host
1606   running the user agent will also serve as a long-lived user
1607   identifier. In environments where proxies are used to enhance
1608   privacy, user agents ought to be conservative in offering accept
1609   header configuration options to end users. As an extreme privacy
1610   measure, proxies could filter the accept header fields in relayed requests.
1611   General purpose user agents which provide a high degree of header
1612   configurability &SHOULD; warn users about the loss of privacy which can
1613   be involved.
1614</t>
1615</section>
1616
1617</section>
1618
1619<section title="Acknowledgments" anchor="acks">
1620<t>
1621  See &acks;.
1622</t>
1623</section>
1624</middle>
1625<back>
1626
1627<references title="Normative References">
1628
1629<reference anchor="Part1">
1630  <front>
1631    <title abbrev="HTTP/1.1">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1632    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1633      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1634      <address><email>fielding@gbiv.com</email></address>
1635    </author>
1636    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1637      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1638      <address><email>jg@freedesktop.org</email></address>
1639    </author>
1640    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1641      <organization abbrev="HP">Hewlett-Packard Company</organization>
1642      <address><email>JeffMogul@acm.org</email></address>
1643    </author>
1644    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1645      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1646      <address><email>henrikn@microsoft.com</email></address>
1647    </author>
1648    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1649      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1650      <address><email>LMM@acm.org</email></address>
1651    </author>
1652    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1653      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1654      <address><email>paulle@microsoft.com</email></address>
1655    </author>
1656    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1657      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1658      <address><email>timbl@w3.org</email></address>
1659    </author>
1660    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1661      <organization abbrev="W3C">World Wide Web Consortium</organization>
1662      <address><email>ylafon@w3.org</email></address>
1663    </author>
1664    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1665      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1666      <address><email>julian.reschke@greenbytes.de</email></address>
1667    </author>
1668    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1669  </front>
1670  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1671  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
1672</reference>
1673
1674<reference anchor="Part2">
1675  <front>
1676    <title abbrev="HTTP/1.1">HTTP/1.1, part 2: Message Semantics</title>
1677    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1678      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1679      <address><email>fielding@gbiv.com</email></address>
1680    </author>
1681    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1682      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1683      <address><email>jg@freedesktop.org</email></address>
1684    </author>
1685    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1686      <organization abbrev="HP">Hewlett-Packard Company</organization>
1687      <address><email>JeffMogul@acm.org</email></address>
1688    </author>
1689    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1690      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1691      <address><email>henrikn@microsoft.com</email></address>
1692    </author>
1693    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1694      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1695      <address><email>LMM@acm.org</email></address>
1696    </author>
1697    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1698      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1699      <address><email>paulle@microsoft.com</email></address>
1700    </author>
1701    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1702      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1703      <address><email>timbl@w3.org</email></address>
1704    </author>
1705    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1706      <organization abbrev="W3C">World Wide Web Consortium</organization>
1707      <address><email>ylafon@w3.org</email></address>
1708    </author>
1709    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1710      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1711      <address><email>julian.reschke@greenbytes.de</email></address>
1712    </author>
1713    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1714  </front>
1715  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1716  <x:source href="p2-semantics.xml" basename="p2-semantics"/>
1717</reference>
1718
1719<reference anchor="Part4">
1720  <front>
1721    <title abbrev="HTTP/1.1">HTTP/1.1, part 4: Conditional Requests</title>
1722    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1723      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1724      <address><email>fielding@gbiv.com</email></address>
1725    </author>
1726    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1727      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1728      <address><email>jg@freedesktop.org</email></address>
1729    </author>
1730    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1731      <organization abbrev="HP">Hewlett-Packard Company</organization>
1732      <address><email>JeffMogul@acm.org</email></address>
1733    </author>
1734    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1735      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1736      <address><email>henrikn@microsoft.com</email></address>
1737    </author>
1738    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1739      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1740      <address><email>LMM@acm.org</email></address>
1741    </author>
1742    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1743      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1744      <address><email>paulle@microsoft.com</email></address>
1745    </author>
1746    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1747      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1748      <address><email>timbl@w3.org</email></address>
1749    </author>
1750    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1751      <organization abbrev="W3C">World Wide Web Consortium</organization>
1752      <address><email>ylafon@w3.org</email></address>
1753    </author>
1754    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1755      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1756      <address><email>julian.reschke@greenbytes.de</email></address>
1757    </author>
1758    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1759  </front>
1760  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1761  <x:source href="p4-conditional.xml" basename="p4-conditional"/>
1762</reference>
1763
1764<reference anchor="Part5">
1765  <front>
1766    <title abbrev="HTTP/1.1">HTTP/1.1, part 5: Range Requests and Partial Responses</title>
1767    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1768      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1769      <address><email>fielding@gbiv.com</email></address>
1770    </author>
1771    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1772      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1773      <address><email>jg@freedesktop.org</email></address>
1774    </author>
1775    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1776      <organization abbrev="HP">Hewlett-Packard Company</organization>
1777      <address><email>JeffMogul@acm.org</email></address>
1778    </author>
1779    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1780      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1781      <address><email>henrikn@microsoft.com</email></address>
1782    </author>
1783    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1784      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1785      <address><email>LMM@acm.org</email></address>
1786    </author>
1787    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1788      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1789      <address><email>paulle@microsoft.com</email></address>
1790    </author>
1791    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1792      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1793      <address><email>timbl@w3.org</email></address>
1794    </author>
1795    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1796      <organization abbrev="W3C">World Wide Web Consortium</organization>
1797      <address><email>ylafon@w3.org</email></address>
1798    </author>
1799    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1800      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1801      <address><email>julian.reschke@greenbytes.de</email></address>
1802    </author>
1803    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1804  </front>
1805  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p5-range-&ID-VERSION;"/>
1806  <x:source href="p5-range.xml" basename="p5-range"/>
1807</reference>
1808
1809<reference anchor="Part6">
1810  <front>
1811    <title abbrev="HTTP/1.1">HTTP/1.1, part 6: Caching</title>
1812    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1813      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1814      <address><email>fielding@gbiv.com</email></address>
1815    </author>
1816    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1817      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1818      <address><email>jg@freedesktop.org</email></address>
1819    </author>
1820    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1821      <organization abbrev="HP">Hewlett-Packard Company</organization>
1822      <address><email>JeffMogul@acm.org</email></address>
1823    </author>
1824    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1825      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1826      <address><email>henrikn@microsoft.com</email></address>
1827    </author>
1828    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1829      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1830      <address><email>LMM@acm.org</email></address>
1831    </author>
1832    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1833      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1834      <address><email>paulle@microsoft.com</email></address>
1835    </author>
1836    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1837      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1838      <address><email>timbl@w3.org</email></address>
1839    </author>
1840    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1841      <organization abbrev="W3C">World Wide Web Consortium</organization>
1842      <address><email>ylafon@w3.org</email></address>
1843    </author>
1844    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1845      <organization>Rackspace</organization>
1846      <address><email>mnot@mnot.net</email></address>
1847    </author>
1848    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1849      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1850      <address><email>julian.reschke@greenbytes.de</email></address>
1851    </author>
1852    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1853  </front>
1854  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1855  <x:source href="p6-cache.xml" basename="p6-cache"/>
1856</reference>
1857
1858<reference anchor="RFC1950">
1859  <front>
1860    <title>ZLIB Compressed Data Format Specification version 3.3</title>
1861    <author initials="L.P." surname="Deutsch" fullname="L. Peter Deutsch">
1862      <organization>Aladdin Enterprises</organization>
1863      <address><email>ghost@aladdin.com</email></address>
1864    </author>
1865    <author initials="J-L." surname="Gailly" fullname="Jean-Loup Gailly"/>
1866    <date month="May" year="1996"/>
1867  </front>
1868  <seriesInfo name="RFC" value="1950"/>
1869  <annotation>
1870    RFC 1950 is an Informational RFC, thus it might be less stable than
1871    this specification. On the other hand, this downward reference was
1872    present since the publication of <xref target="RFC2068" x:fmt="none">RFC 2068</xref> in 1997,
1873    therefore it is unlikely to cause problems in practice. See also
1874    <xref target="BCP97"/>.
1875  </annotation>
1876</reference>
1877
1878<reference anchor="RFC1951">
1879  <front>
1880    <title>DEFLATE Compressed Data Format Specification version 1.3</title>
1881    <author initials="P." surname="Deutsch" fullname="L. Peter Deutsch">
1882      <organization>Aladdin Enterprises</organization>
1883      <address><email>ghost@aladdin.com</email></address>
1884    </author>
1885    <date month="May" year="1996"/>
1886  </front>
1887  <seriesInfo name="RFC" value="1951"/>
1888  <annotation>
1889    RFC 1951 is an Informational RFC, thus it might be less stable than
1890    this specification. On the other hand, this downward reference was
1891    present since the publication of <xref target="RFC2068" x:fmt="none">RFC 2068</xref> in 1997,
1892    therefore it is unlikely to cause problems in practice. See also
1893    <xref target="BCP97"/>.
1894  </annotation>
1895</reference>
1896
1897<reference anchor="RFC1952">
1898  <front>
1899    <title>GZIP file format specification version 4.3</title>
1900    <author initials="P." surname="Deutsch" fullname="L. Peter Deutsch">
1901      <organization>Aladdin Enterprises</organization>
1902      <address><email>ghost@aladdin.com</email></address>
1903    </author>
1904    <author initials="J-L." surname="Gailly" fullname="Jean-Loup Gailly">
1905      <address><email>gzip@prep.ai.mit.edu</email></address>
1906    </author>
1907    <author initials="M." surname="Adler" fullname="Mark Adler">
1908      <address><email>madler@alumni.caltech.edu</email></address>
1909    </author>
1910    <author initials="L.P." surname="Deutsch" fullname="L. Peter Deutsch">
1911      <address><email>ghost@aladdin.com</email></address>
1912    </author>
1913    <author initials="G." surname="Randers-Pehrson" fullname="Glenn Randers-Pehrson">
1914      <address><email>randeg@alumni.rpi.edu</email></address>
1915    </author>
1916    <date month="May" year="1996"/>
1917  </front>
1918  <seriesInfo name="RFC" value="1952"/>
1919  <annotation>
1920    RFC 1952 is an Informational RFC, thus it might be less stable than
1921    this specification. On the other hand, this downward reference was
1922    present since the publication of <xref target="RFC2068" x:fmt="none">RFC 2068</xref> in 1997,
1923    therefore it is unlikely to cause problems in practice. See also
1924    <xref target="BCP97"/>.
1925  </annotation>
1926</reference>
1927
1928<reference anchor="RFC2045">
1929  <front>
1930    <title abbrev="Internet Message Bodies">Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</title>
1931    <author initials="N." surname="Freed" fullname="Ned Freed">
1932      <organization>Innosoft International, Inc.</organization>
1933      <address><email>ned@innosoft.com</email></address>
1934    </author>
1935    <author initials="N.S." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1936      <organization>First Virtual Holdings</organization>
1937      <address><email>nsb@nsb.fv.com</email></address>
1938    </author>
1939    <date month="November" year="1996"/>
1940  </front>
1941  <seriesInfo name="RFC" value="2045"/>
1942</reference>
1943
1944<reference anchor="RFC2046">
1945  <front>
1946    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1947    <author initials="N." surname="Freed" fullname="Ned Freed">
1948      <organization>Innosoft International, Inc.</organization>
1949      <address><email>ned@innosoft.com</email></address>
1950    </author>
1951    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1952      <organization>First Virtual Holdings</organization>
1953      <address><email>nsb@nsb.fv.com</email></address>
1954    </author>
1955    <date month="November" year="1996"/>
1956  </front>
1957  <seriesInfo name="RFC" value="2046"/>
1958</reference>
1959
1960<reference anchor="RFC2119">
1961  <front>
1962    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1963    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1964      <organization>Harvard University</organization>
1965      <address><email>sob@harvard.edu</email></address>
1966    </author>
1967    <date month="March" year="1997"/>
1968  </front>
1969  <seriesInfo name="BCP" value="14"/>
1970  <seriesInfo name="RFC" value="2119"/>
1971</reference>
1972
1973<reference anchor='RFC4647'>
1974  <front>
1975    <title>Matching of Language Tags</title>
1976    <author initials='A.' surname='Phillips' fullname='Addison Phillips' role="editor">
1977      <organization>Yahoo! Inc.</organization>
1978      <address><email>addison@inter-locale.com</email></address>
1979    </author>
1980    <author initials='M.' surname='Davis' fullname='Mark Davis' role="editor">
1981      <organization>Google</organization>
1982      <address><email>mark.davis@macchiato.com</email></address>
1983    </author>
1984    <date year='2006' month='September' />
1985  </front>
1986  <seriesInfo name='BCP' value='47' />
1987  <seriesInfo name='RFC' value='4647' />
1988</reference>
1989
1990<reference anchor="RFC5234">
1991  <front>
1992    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1993    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1994      <organization>Brandenburg InternetWorking</organization>
1995      <address>
1996        <email>dcrocker@bbiw.net</email>
1997      </address> 
1998    </author>
1999    <author initials="P." surname="Overell" fullname="Paul Overell">
2000      <organization>THUS plc.</organization>
2001      <address>
2002        <email>paul.overell@thus.net</email>
2003      </address>
2004    </author>
2005    <date month="January" year="2008"/>
2006  </front>
2007  <seriesInfo name="STD" value="68"/>
2008  <seriesInfo name="RFC" value="5234"/>
2009</reference>
2010
2011<reference anchor='RFC5646'>
2012  <front>
2013    <title>Tags for Identifying Languages</title>
2014    <author initials='A.' surname='Phillips' fullname='Addison Phillips' role='editor'>
2015      <organization>Lab126</organization>
2016      <address><email>addison@inter-locale.com</email></address>
2017    </author>
2018    <author initials='M.' surname='Davis' fullname='Mark Davis' role='editor'>
2019      <organization>Google</organization>
2020      <address><email>mark.davis@google.com</email></address>
2021    </author>
2022    <date month='September' year='2009' />
2023  </front>
2024  <seriesInfo name='BCP' value='47' />
2025  <seriesInfo name='RFC' value='5646' />
2026</reference>
2027
2028</references>
2029
2030<references title="Informative References">
2031
2032<reference anchor="RFC1945">
2033  <front>
2034    <title abbrev="HTTP/1.0">Hypertext Transfer Protocol -- HTTP/1.0</title>
2035    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
2036      <organization>MIT, Laboratory for Computer Science</organization>
2037      <address><email>timbl@w3.org</email></address>
2038    </author>
2039    <author initials="R.T." surname="Fielding" fullname="Roy T. Fielding">
2040      <organization>University of California, Irvine, Department of Information and Computer Science</organization>
2041      <address><email>fielding@ics.uci.edu</email></address>
2042    </author>
2043    <author initials="H.F." surname="Nielsen" fullname="Henrik Frystyk Nielsen">
2044      <organization>W3 Consortium, MIT Laboratory for Computer Science</organization>
2045      <address><email>frystyk@w3.org</email></address>
2046    </author>
2047    <date month="May" year="1996"/>
2048  </front>
2049  <seriesInfo name="RFC" value="1945"/>
2050</reference>
2051
2052<reference anchor="RFC2049">
2053  <front>
2054    <title abbrev="MIME Conformance">Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples</title>
2055    <author initials="N." surname="Freed" fullname="Ned Freed">
2056      <organization>Innosoft International, Inc.</organization>
2057      <address><email>ned@innosoft.com</email></address>
2058    </author>
2059    <author initials="N.S." surname="Borenstein" fullname="Nathaniel S. Borenstein">
2060      <organization>First Virtual Holdings</organization>
2061      <address><email>nsb@nsb.fv.com</email></address>
2062    </author>
2063    <date month="November" year="1996"/>
2064  </front>
2065  <seriesInfo name="RFC" value="2049"/>
2066</reference>
2067
2068<reference anchor="RFC2068">
2069  <front>
2070    <title abbrev="HTTP/1.1">Hypertext Transfer Protocol -- HTTP/1.1</title>
2071    <author initials="R." surname="Fielding" fullname="Roy T. Fielding">
2072      <organization>University of California, Irvine, Department of Information and Computer Science</organization>
2073      <address><email>fielding@ics.uci.edu</email></address>
2074    </author>
2075    <author initials="J." surname="Gettys" fullname="Jim Gettys">
2076      <organization>MIT Laboratory for Computer Science</organization>
2077      <address><email>jg@w3.org</email></address>
2078    </author>
2079    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
2080      <organization>Digital Equipment Corporation, Western Research Laboratory</organization>
2081      <address><email>mogul@wrl.dec.com</email></address>
2082    </author>
2083    <author initials="H." surname="Nielsen" fullname="Henrik Frystyk Nielsen">
2084      <organization>MIT Laboratory for Computer Science</organization>
2085      <address><email>frystyk@w3.org</email></address>
2086    </author>
2087    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
2088      <organization>MIT Laboratory for Computer Science</organization>
2089      <address><email>timbl@w3.org</email></address>
2090    </author>
2091    <date month="January" year="1997"/>
2092  </front>
2093  <seriesInfo name="RFC" value="2068"/>
2094</reference>
2095
2096<reference anchor="RFC2076">
2097  <front>
2098    <title abbrev="Internet Message Headers">Common Internet Message Headers</title>
2099    <author initials="J." surname="Palme" fullname="Jacob Palme">
2100      <organization>Stockholm University/KTH</organization>
2101      <address><email>jpalme@dsv.su.se</email></address>
2102    </author>
2103    <date month="February" year="1997"/>
2104  </front>
2105  <seriesInfo name="RFC" value="2076"/>
2106</reference>
2107
2108<reference anchor="RFC2277">
2109  <front>
2110    <title abbrev="Charset Policy">IETF Policy on Character Sets and Languages</title>
2111    <author initials="H.T." surname="Alvestrand" fullname="Harald Tveit Alvestrand">
2112      <organization>UNINETT</organization>
2113      <address><email>Harald.T.Alvestrand@uninett.no</email></address>
2114    </author>
2115    <date month="January" year="1998"/>
2116  </front>
2117  <seriesInfo name="BCP" value="18"/>
2118  <seriesInfo name="RFC" value="2277"/>
2119</reference>
2120
2121<reference anchor='RFC2295'>
2122  <front>
2123    <title abbrev='HTTP Content Negotiation'>Transparent Content Negotiation in HTTP</title>
2124    <author initials='K.' surname='Holtman' fullname='Koen Holtman'>
2125      <organization>Technische Universiteit Eindhoven</organization>
2126      <address>
2127        <email>koen@win.tue.nl</email>
2128      </address>
2129    </author>
2130    <author initials='A.H.' surname='Mutz' fullname='Andrew H. Mutz'>
2131      <organization>Hewlett-Packard Company</organization>
2132      <address>
2133        <email>mutz@hpl.hp.com</email>
2134      </address>
2135    </author>
2136    <date year='1998' month='March'/>
2137  </front>
2138  <seriesInfo name='RFC' value='2295'/>
2139</reference>
2140
2141<reference anchor="RFC2388">
2142  <front>
2143    <title abbrev="multipart/form-data">Returning Values from Forms:  multipart/form-data</title>
2144    <author initials="L." surname="Masinter" fullname="Larry Masinter">
2145      <organization>Xerox Palo Alto Research Center</organization>
2146      <address><email>masinter@parc.xerox.com</email></address>
2147    </author>
2148    <date year="1998" month="August"/>
2149  </front>
2150  <seriesInfo name="RFC" value="2388"/>
2151</reference>
2152
2153<reference anchor="RFC2557">
2154  <front>
2155    <title abbrev="MIME Encapsulation of Aggregate Documents">MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)</title>
2156    <author initials="F." surname="Palme" fullname="Jacob Palme">
2157      <organization>Stockholm University and KTH</organization>
2158      <address><email>jpalme@dsv.su.se</email></address>
2159    </author>
2160    <author initials="A." surname="Hopmann" fullname="Alex Hopmann">
2161      <organization>Microsoft Corporation</organization>
2162      <address><email>alexhop@microsoft.com</email></address>
2163    </author>
2164    <author initials="N." surname="Shelness" fullname="Nick Shelness">
2165      <organization>Lotus Development Corporation</organization>
2166      <address><email>Shelness@lotus.com</email></address>
2167    </author>
2168    <author initials="E." surname="Stefferud" fullname="Einar Stefferud">
2169      <address><email>stef@nma.com</email></address>
2170    </author>
2171    <date year="1999" month="March"/>
2172  </front>
2173  <seriesInfo name="RFC" value="2557"/>
2174</reference>
2175
2176<reference anchor="RFC2616">
2177  <front>
2178    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
2179    <author initials="R." surname="Fielding" fullname="R. Fielding">
2180      <organization>University of California, Irvine</organization>
2181      <address><email>fielding@ics.uci.edu</email></address>
2182    </author>
2183    <author initials="J." surname="Gettys" fullname="J. Gettys">
2184      <organization>W3C</organization>
2185      <address><email>jg@w3.org</email></address>
2186    </author>
2187    <author initials="J." surname="Mogul" fullname="J. Mogul">
2188      <organization>Compaq Computer Corporation</organization>
2189      <address><email>mogul@wrl.dec.com</email></address>
2190    </author>
2191    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
2192      <organization>MIT Laboratory for Computer Science</organization>
2193      <address><email>frystyk@w3.org</email></address>
2194    </author>
2195    <author initials="L." surname="Masinter" fullname="L. Masinter">
2196      <organization>Xerox Corporation</organization>
2197      <address><email>masinter@parc.xerox.com</email></address>
2198    </author>
2199    <author initials="P." surname="Leach" fullname="P. Leach">
2200      <organization>Microsoft Corporation</organization>
2201      <address><email>paulle@microsoft.com</email></address>
2202    </author>
2203    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
2204      <organization>W3C</organization>
2205      <address><email>timbl@w3.org</email></address>
2206    </author>
2207    <date month="June" year="1999"/>
2208  </front>
2209  <seriesInfo name="RFC" value="2616"/>
2210</reference>
2211
2212<reference anchor="RFC3629">
2213  <front>
2214    <title>UTF-8, a transformation format of ISO 10646</title>
2215    <author initials="F." surname="Yergeau" fullname="F. Yergeau">
2216      <organization>Alis Technologies</organization>
2217      <address><email>fyergeau@alis.com</email></address>
2218    </author>
2219    <date month="November" year="2003"/>
2220  </front>
2221  <seriesInfo name="STD" value="63"/>
2222  <seriesInfo name="RFC" value="3629"/>
2223</reference>
2224
2225<reference anchor='RFC3864'>
2226  <front>
2227    <title>Registration Procedures for Message Header Fields</title>
2228    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
2229      <organization>Nine by Nine</organization>
2230      <address><email>GK-IETF@ninebynine.org</email></address>
2231    </author>
2232    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
2233      <organization>BEA Systems</organization>
2234      <address><email>mnot@pobox.com</email></address>
2235    </author>
2236    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
2237      <organization>HP Labs</organization>
2238      <address><email>JeffMogul@acm.org</email></address>
2239    </author>
2240    <date year='2004' month='September' />
2241  </front>
2242  <seriesInfo name='BCP' value='90' />
2243  <seriesInfo name='RFC' value='3864' />
2244</reference>
2245
2246<reference anchor="RFC4288">
2247  <front>
2248    <title>Media Type Specifications and Registration Procedures</title>
2249    <author initials="N." surname="Freed" fullname="N. Freed">
2250      <organization>Sun Microsystems</organization>
2251      <address>
2252        <email>ned.freed@mrochek.com</email>
2253      </address>
2254    </author>
2255    <author initials="J." surname="Klensin" fullname="J. Klensin">
2256      <address>
2257        <email>klensin+ietf@jck.com</email>
2258      </address>
2259    </author>
2260    <date year="2005" month="December"/>
2261  </front>
2262  <seriesInfo name="BCP" value="13"/>
2263  <seriesInfo name="RFC" value="4288"/>
2264</reference>
2265
2266<reference anchor='RFC5226'>
2267  <front>
2268    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
2269    <author initials='T.' surname='Narten' fullname='T. Narten'>
2270      <organization>IBM</organization>
2271      <address><email>narten@us.ibm.com</email></address>
2272    </author>
2273    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
2274      <organization>Google</organization>
2275      <address><email>Harald@Alvestrand.no</email></address>
2276    </author>
2277    <date year='2008' month='May' />
2278  </front>
2279  <seriesInfo name='BCP' value='26' />
2280  <seriesInfo name='RFC' value='5226' />
2281</reference>
2282
2283<reference anchor="RFC5322">
2284  <front>
2285    <title>Internet Message Format</title>
2286    <author initials="P." surname="Resnick" fullname="P. Resnick">
2287      <organization>Qualcomm Incorporated</organization>
2288    </author>
2289    <date year="2008" month="October"/>
2290  </front> 
2291  <seriesInfo name="RFC" value="5322"/>
2292</reference>
2293
2294<reference anchor="RFC6151">
2295  <front>
2296    <title>Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms</title>
2297    <author initials="S." surname="Turner" fullname="S. Turner"/>
2298    <author initials="L." surname="Chen" fullname="L. Chen"/>
2299    <date year="2011" month="March" />
2300  </front>
2301  <seriesInfo name="RFC" value="6151" />
2302</reference>
2303
2304<reference anchor='BCP97'>
2305  <front>
2306    <title>Handling Normative References to Standards-Track Documents</title>
2307    <author initials='J.' surname='Klensin' fullname='J. Klensin'>
2308      <address>
2309        <email>klensin+ietf@jck.com</email>
2310      </address>
2311    </author>
2312    <author initials='S.' surname='Hartman' fullname='S. Hartman'>
2313      <organization>MIT</organization>
2314      <address>
2315        <email>hartmans-ietf@mit.edu</email>
2316      </address>
2317    </author>
2318    <date year='2007' month='June' />
2319  </front>
2320  <seriesInfo name='BCP' value='97' />
2321  <seriesInfo name='RFC' value='4897' />
2322</reference>
2323
2324<reference anchor="RFC6266">
2325  <front>
2326    <title abbrev="Content-Disposition in HTTP">Use of the Content-Disposition Header Field
2327    in the Hypertext Transfer Protocol (HTTP)</title>
2328    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke">
2329      <organization abbrev="greenbytes">greenbytes GmbH</organization>
2330      <address>
2331        <email>julian.reschke@greenbytes.de</email>
2332      </address>
2333    </author>
2334    <date month="June" year="2011"/>
2335  </front>
2336  <seriesInfo name='RFC' value='6266' />
2337</reference>
2338
2339</references>
2340
2341<section title="Differences between HTTP and MIME" anchor="differences.between.http.and.mime">
2342<t>
2343   HTTP/1.1 uses many of the constructs defined for Internet Mail (<xref target="RFC5322"/>) and the Multipurpose Internet Mail Extensions (MIME <xref target="RFC2045"/>) to
2344   allow a message-body to be transmitted in an open variety of
2345   representations and with extensible mechanisms. However, RFC 2045
2346   discusses mail, and HTTP has a few features that are different from
2347   those described in MIME. These differences were carefully chosen
2348   to optimize performance over binary connections, to allow greater
2349   freedom in the use of new media types, to make date comparisons
2350   easier, and to acknowledge the practice of some early HTTP servers
2351   and clients.
2352</t>
2353<t>
2354   This appendix describes specific areas where HTTP differs from MIME.
2355   Proxies and gateways to strict MIME environments &SHOULD; be
2356   aware of these differences and provide the appropriate conversions
2357   where necessary. Proxies and gateways from MIME environments to HTTP
2358   also need to be aware of the differences because some conversions
2359   might be required.
2360</t>
2361
2362<section title="MIME-Version" anchor="mime-version">
2363  <iref primary="true" item="MIME-Version header field" x:for-anchor=""/>
2364  <iref primary="true" item="Header Fields" subitem="MIME-Version" x:for-anchor=""/>
2365  <x:anchor-alias value="MIME-Version"/>
2366<t>
2367   HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages &MAY;
2368   include a single MIME-Version header field to indicate what
2369   version of the MIME protocol was used to construct the message. Use
2370   of the MIME-Version header field indicates that the message is in
2371   full compliance with the MIME protocol (as defined in <xref target="RFC2045"/>).
2372   Proxies/gateways are responsible for ensuring full compliance (where
2373   possible) when exporting HTTP messages to strict MIME environments.
2374</t>
2375<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="MIME-Version"/>
2376  <x:ref>MIME-Version</x:ref> = 1*<x:ref>DIGIT</x:ref> "." 1*<x:ref>DIGIT</x:ref>
2377</artwork></figure>
2378<t>
2379   MIME version "1.0" is the default for use in HTTP/1.1. However,
2380   HTTP/1.1 message parsing and semantics are defined by this document
2381   and not the MIME specification.
2382</t>
2383</section>
2384
2385<section title="Conversion to Canonical Form" anchor="conversion.to.canonical.form">
2386<t>
2387   MIME requires that an Internet mail body-part be converted to
2388   canonical form prior to being transferred, as described in <xref target="RFC2049" x:fmt="of" x:sec="4"/>.
2389   <xref target="canonicalization.and.text.defaults"/> of this document describes the forms
2390   allowed for subtypes of the "text" media type when transmitted over
2391   HTTP. <xref target="RFC2046"/> requires that content with a type of "text" represent
2392   line breaks as CRLF and forbids the use of CR or LF outside of line
2393   break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a
2394   line break within text content when a message is transmitted over
2395   HTTP.
2396</t>
2397<t>
2398   Where it is possible, a proxy or gateway from HTTP to a strict MIME
2399   environment &SHOULD; translate all line breaks within the text media
2400   types described in <xref target="canonicalization.and.text.defaults"/>
2401   of this document to the RFC 2049
2402   canonical form of CRLF. Note, however, that this might be complicated
2403   by the presence of a Content-Encoding and by the fact that HTTP
2404   allows the use of some character encodings which do not use octets 13 and
2405   10 to represent CR and LF, respectively, as is the case for some multi-byte
2406   character encodings.
2407</t>
2408<t>
2409   Conversion will break any cryptographic
2410   checksums applied to the original content unless the original content
2411   is already in canonical form. Therefore, the canonical form is
2412   recommended for any content that uses such checksums in HTTP.
2413</t>
2414</section>
2415
2416
2417<section title="Conversion of Date Formats" anchor="conversion.of.date.formats">
2418<t>
2419   HTTP/1.1 uses a restricted set of date formats (&http-date;) to
2420   simplify the process of date comparison. Proxies and gateways from
2421   other protocols &SHOULD; ensure that any Date header field present in a
2422   message conforms to one of the HTTP/1.1 formats and rewrite the date
2423   if necessary.
2424</t>
2425</section>
2426
2427<section title="Introduction of Content-Encoding" anchor="introduction.of.content-encoding">
2428<t>
2429   MIME does not include any concept equivalent to HTTP/1.1's
2430   Content-Encoding header field. Since this acts as a modifier on the
2431   media type, proxies and gateways from HTTP to MIME-compliant
2432   protocols &MUST; either change the value of the Content-Type header
2433   field or decode the representation before forwarding the message. (Some
2434   experimental applications of Content-Type for Internet mail have used
2435   a media-type parameter of ";conversions=&lt;content-coding&gt;" to perform
2436   a function equivalent to Content-Encoding. However, this parameter is
2437   not part of the MIME standards).
2438</t>
2439</section>
2440
2441<section title="No Content-Transfer-Encoding" anchor="no.content-transfer-encoding">
2442<t>
2443   HTTP does not use the Content-Transfer-Encoding field of MIME.
2444   Proxies and gateways from MIME-compliant protocols to HTTP &MUST;
2445   remove any Content-Transfer-Encoding
2446   prior to delivering the response message to an HTTP client.
2447</t>
2448<t>
2449   Proxies and gateways from HTTP to MIME-compliant protocols are
2450   responsible for ensuring that the message is in the correct format
2451   and encoding for safe transport on that protocol, where "safe
2452   transport" is defined by the limitations of the protocol being used.
2453   Such a proxy or gateway &SHOULD; label the data with an appropriate
2454   Content-Transfer-Encoding if doing so will improve the likelihood of
2455   safe transport over the destination protocol.
2456</t>
2457</section>
2458
2459<section title="Introduction of Transfer-Encoding" anchor="introduction.of.transfer-encoding">
2460<t>
2461   HTTP/1.1 introduces the Transfer-Encoding header field (&header-transfer-encoding;).
2462   Proxies/gateways &MUST; remove any transfer-coding prior to
2463   forwarding a message via a MIME-compliant protocol.
2464</t>
2465</section>
2466
2467<section title="MHTML and Line Length Limitations" anchor="mhtml.line.length">
2468<t>
2469   HTTP implementations which share code with MHTML <xref target="RFC2557"/> implementations
2470   need to be aware of MIME line length limitations. Since HTTP does not
2471   have this limitation, HTTP does not fold long lines. MHTML messages
2472   being transported by HTTP follow all conventions of MHTML, including
2473   line length limitations and folding, canonicalization, etc., since
2474   HTTP transports all message-bodies as payload (see <xref target="multipart.types"/>) and
2475   does not interpret the content or any MIME header lines that might be
2476   contained therein.
2477</t>
2478</section>
2479</section>
2480
2481<section title="Additional Features" anchor="additional.features">
2482<t>
2483   <xref target="RFC1945"/> and <xref target="RFC2068"/> document protocol elements used by some
2484   existing HTTP implementations, but not consistently and correctly
2485   across most HTTP/1.1 applications. Implementors are advised to be
2486   aware of these features, but cannot rely upon their presence in, or
2487   interoperability with, other HTTP/1.1 applications. Some of these
2488   describe proposed experimental features, and some describe features
2489   that experimental deployment found lacking that are now addressed in
2490   the base HTTP/1.1 specification.
2491</t>
2492<t>
2493   A number of other header fields, such as Content-Disposition and Title,
2494   from SMTP and MIME are also often implemented (see <xref target="RFC6266"/>
2495   and <xref target="RFC2076"/>).
2496</t>
2497</section>
2498
2499<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
2500<t>
2501  Clarify contexts that charset is used in.
2502  (<xref target="character.sets"/>)
2503</t>
2504<t>
2505  Remove the default character encoding for text media types; the default
2506  now is whatever the media type definition says.
2507  (<xref target="canonicalization.and.text.defaults"/>)
2508</t>
2509<t>
2510  Change ABNF productions for header fields to only define the field value.
2511  (<xref target="header.field.definitions"/>)
2512</t>
2513<t>
2514  Remove definition of Content-MD5 header field because it was inconsistently
2515  implemented with respect to partial responses, and also because of known
2516  deficiencies in the hash algorithm itself (see <xref target="RFC6151"/> for details).
2517  (<xref target="header.field.definitions"/>)
2518</t>
2519<t>
2520  Remove ISO-8859-1 special-casing in Accept-Charset.
2521  (<xref target="header.accept-charset"/>)
2522</t>
2523<t>
2524  Remove base URI setting semantics for Content-Location due to poor
2525  implementation support, which was caused by too many broken servers emitting
2526  bogus Content-Location header fields, and also the potentially undesirable effect
2527  of potentially breaking relative links in content-negotiated resources.
2528  (<xref target="header.content-location"/>)
2529</t>
2530<t>
2531  Remove discussion of Content-Disposition header field, it is now defined
2532  by <xref target="RFC6266"/>.
2533  (<xref target="additional.features"/>)
2534</t>
2535<t>
2536  Remove reference to non-existant identity transfer-coding value tokens.
2537  (<xref target="no.content-transfer-encoding"/>)
2538</t>
2539</section>
2540
2541<?BEGININC p3-payload.abnf-appendix ?>
2542<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
2543<figure>
2544<artwork type="abnf" name="p3-payload.parsed-abnf">
2545<x:ref>Accept</x:ref> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [
2546 OWS media-range [ accept-params ] ] ) ]
2547<x:ref>Accept-Charset</x:ref> = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q="
2548 qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q="
2549 qvalue ] ] )
2550<x:ref>Accept-Encoding</x:ref> = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) )
2551 *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ]
2552<x:ref>Accept-Language</x:ref> = *( "," OWS ) language-range [ OWS ";" OWS "q="
2553 qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ]
2554 ] )
2555
2556<x:ref>Content-Encoding</x:ref> = *( "," OWS ) content-coding *( OWS "," [ OWS
2557 content-coding ] )
2558<x:ref>Content-Language</x:ref> = *( "," OWS ) language-tag *( OWS "," [ OWS
2559 language-tag ] )
2560<x:ref>Content-Location</x:ref> = absolute-URI / partial-URI
2561<x:ref>Content-Type</x:ref> = media-type
2562
2563<x:ref>MIME-Version</x:ref> = 1*DIGIT "." 1*DIGIT
2564
2565<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 1.2.2&gt;
2566
2567<x:ref>absolute-URI</x:ref> = &lt;absolute-URI, defined in [Part1], Section 2.7&gt;
2568<x:ref>accept-ext</x:ref> = OWS ";" OWS token [ "=" word ]
2569<x:ref>accept-params</x:ref> = OWS ";" OWS "q=" qvalue *accept-ext
2570<x:ref>attribute</x:ref> = token
2571
2572<x:ref>charset</x:ref> = token
2573<x:ref>codings</x:ref> = content-coding / "identity" / "*"
2574<x:ref>content-coding</x:ref> = token
2575
2576<x:ref>language-range</x:ref> = &lt;language-range, defined in [RFC4647], Section 2.1&gt;
2577<x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in [RFC5646], Section 2.1&gt;
2578
2579<x:ref>media-range</x:ref> = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS
2580 ";" OWS parameter )
2581<x:ref>media-type</x:ref> = type "/" subtype *( OWS ";" OWS parameter )
2582
2583<x:ref>parameter</x:ref> = attribute "=" value
2584<x:ref>partial-URI</x:ref> = &lt;partial-URI, defined in [Part1], Section 2.7&gt;
2585
2586<x:ref>qvalue</x:ref> = &lt;qvalue, defined in [Part1], Section 5.3&gt;
2587
2588<x:ref>subtype</x:ref> = token
2589
2590<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.3&gt;
2591<x:ref>type</x:ref> = token
2592
2593<x:ref>value</x:ref> = word
2594
2595<x:ref>word</x:ref> = &lt;word, defined in [Part1], Section 3.2.3&gt;
2596</artwork>
2597</figure>
2598<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
2599; Accept defined but not used
2600; Accept-Charset defined but not used
2601; Accept-Encoding defined but not used
2602; Accept-Language defined but not used
2603; Content-Encoding defined but not used
2604; Content-Language defined but not used
2605; Content-Location defined but not used
2606; Content-Type defined but not used
2607; MIME-Version defined but not used
2608</artwork></figure></section>
2609<?ENDINC p3-payload.abnf-appendix ?>
2610
2611<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
2612
2613<section title="Since RFC 2616">
2614<t>
2615  Extracted relevant partitions from <xref target="RFC2616"/>.
2616</t>
2617</section>
2618
2619<section title="Since draft-ietf-httpbis-p3-payload-00">
2620<t>
2621  Closed issues:
2622  <list style="symbols"> 
2623    <t>
2624      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/8"/>:
2625      "Media Type Registrations"
2626      (<eref target="http://purl.org/NET/http-errata#media-reg"/>)
2627    </t>
2628    <t>
2629      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/14"/>:
2630      "Clarification regarding quoting of charset values"
2631      (<eref target="http://purl.org/NET/http-errata#charactersets"/>)
2632    </t>
2633    <t>
2634      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/16"/>:
2635      "Remove 'identity' token references"
2636      (<eref target="http://purl.org/NET/http-errata#identity"/>)
2637    </t>
2638    <t>
2639      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/25"/>:
2640      "Accept-Encoding BNF"
2641    </t>
2642    <t>
2643      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
2644      "Normative and Informative references"
2645    </t>
2646    <t>
2647      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/46"/>:
2648      "RFC1700 references"
2649    </t>
2650    <t>
2651      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
2652      "Updating to RFC4288"
2653    </t>
2654    <t>
2655      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/65"/>:
2656      "Informative references"
2657    </t>
2658    <t>
2659      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/66"/>:
2660      "ISO-8859-1 Reference"
2661    </t>
2662    <t>
2663      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>:
2664      "Encoding References Normative"
2665    </t>
2666    <t>
2667      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
2668      "Normative up-to-date references"
2669    </t>
2670  </list>
2671</t>
2672</section>
2673
2674<section title="Since draft-ietf-httpbis-p3-payload-01">
2675<t>
2676  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2677  <list style="symbols"> 
2678    <t>
2679      Add explicit references to BNF syntax and rules imported from other parts of the specification.
2680    </t>
2681  </list>
2682</t>
2683</section>
2684
2685<section title="Since draft-ietf-httpbis-p3-payload-02" anchor="changes.since.02">
2686<t>
2687  Closed issues:
2688  <list style="symbols"> 
2689    <t>
2690      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>:
2691      "Quoting Charsets"
2692    </t>
2693    <t>
2694      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/105"/>:
2695      "Classification for Allow header"
2696    </t>
2697    <t>
2698      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/115"/>:
2699      "missing default for qvalue in description of Accept-Encoding"
2700    </t>
2701  </list>
2702</t>
2703<t>
2704  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
2705  <list style="symbols"> 
2706    <t>
2707      Reference RFC 3984, and update header field registrations for headers defined
2708      in this document.
2709    </t>
2710  </list>
2711</t>
2712</section>
2713
2714<section title="Since draft-ietf-httpbis-p3-payload-03" anchor="changes.since.03">
2715<t>
2716  Closed issues:
2717  <list style="symbols"> 
2718    <t>
2719      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>:
2720      "Quoting Charsets"
2721    </t>
2722    <t>
2723      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/113"/>:
2724      "language tag matching (Accept-Language) vs RFC4647"
2725    </t>
2726    <t>
2727      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/121"/>:
2728      "RFC 1806 has been replaced by RFC2183"
2729    </t>
2730  </list>
2731</t>
2732<t>
2733  Other changes:
2734  <list style="symbols"> 
2735    <t>
2736      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>:
2737      "Encoding References Normative" &mdash; rephrase the annotation and reference
2738      <xref target="BCP97"/>.
2739    </t>
2740  </list>
2741</t>
2742 </section>
2743
2744<section title="Since draft-ietf-httpbis-p3-payload-04" anchor="changes.since.04">
2745<t>
2746  Closed issues:
2747  <list style="symbols"> 
2748    <t>
2749      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/132"/>:
2750      "RFC 2822 is updated by RFC 5322"
2751    </t>
2752  </list>
2753</t>
2754<t>
2755  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2756  <list style="symbols"> 
2757    <t>
2758      Use "/" instead of "|" for alternatives.
2759    </t>
2760    <t>
2761      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
2762      whitespace ("OWS") and required whitespace ("RWS").
2763    </t>
2764    <t>
2765      Rewrite ABNFs to spell out whitespace rules, factor out
2766      header field value format definitions.
2767    </t>
2768  </list>
2769</t>
2770</section>
2771
2772<section title="Since draft-ietf-httpbis-p3-payload-05" anchor="changes.since.05">
2773<t>
2774  Closed issues:
2775  <list style="symbols"> 
2776    <t>
2777      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/118"/>:
2778      "Join "Differences Between HTTP Entities and RFC 2045 Entities"?"
2779    </t>
2780  </list>
2781</t>
2782<t>
2783  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2784  <list style="symbols"> 
2785    <t>
2786      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
2787    </t>
2788  </list>
2789</t>
2790<t>
2791  Other changes:
2792  <list style="symbols"> 
2793    <t>
2794      Move definition of quality values into Part 1.
2795    </t>
2796  </list>
2797</t>
2798</section>
2799
2800<section title="Since draft-ietf-httpbis-p3-payload-06" anchor="changes.since.06">
2801<t>
2802  Closed issues:
2803  <list style="symbols"> 
2804    <t>
2805      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>:
2806      "Content-Location isn't special"
2807    </t>
2808    <t>
2809      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2810      "Content Sniffing"
2811    </t>
2812  </list>
2813</t>
2814</section>
2815
2816<section title="Since draft-ietf-httpbis-p3-payload-07" anchor="changes.since.07">
2817<t>
2818  Closed issues:
2819  <list style="symbols"> 
2820    <t>
2821      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/13"/>:
2822      "Updated reference for language tags"
2823    </t>
2824    <t>
2825      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/110"/>:
2826      "Clarify rules for determining what entities a response carries"
2827    </t>
2828    <t>
2829      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/154"/>:
2830      "Content-Location base-setting problems"
2831    </t>
2832    <t>
2833      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2834      "Content Sniffing"
2835    </t>
2836    <t>
2837      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/188"/>:
2838      "pick IANA policy (RFC5226) for Transfer Coding / Content Coding"
2839    </t>
2840    <t>
2841      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/189"/>:
2842      "move definitions of gzip/deflate/compress to part 1"
2843    </t>
2844  </list>
2845</t>
2846<t>
2847  Partly resolved issues:
2848  <list style="symbols"> 
2849    <t>
2850      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/148"/>:
2851      "update IANA requirements wrt Transfer-Coding values" (add the
2852      IANA Considerations subsection)
2853    </t>
2854    <t>
2855      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/149"/>:
2856      "update IANA requirements wrt Content-Coding values" (add the
2857      IANA Considerations subsection)
2858    </t>
2859  </list>
2860</t>
2861</section>
2862
2863<section title="Since draft-ietf-httpbis-p3-payload-08" anchor="changes.since.08">
2864<t>
2865  Closed issues:
2866  <list style="symbols"> 
2867    <t>
2868      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/81"/>:
2869      "Content Negotiation for media types"
2870    </t>
2871    <t>
2872      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/181"/>:
2873      "Accept-Language: which RFC4647 filtering?"
2874    </t>
2875  </list>
2876</t>
2877</section>
2878
2879<section title="Since draft-ietf-httpbis-p3-payload-09" anchor="changes.since.09">
2880<t>
2881  Closed issues:
2882  <list style="symbols"> 
2883    <t>
2884      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/122"/>:
2885      "MIME-Version not listed in P1, general header fields"
2886    </t>
2887    <t>
2888      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/143"/>:
2889      "IANA registry for content/transfer encodings"
2890    </t>
2891    <t>
2892      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2893      "Content Sniffing"
2894    </t>
2895    <t>
2896      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/200"/>:
2897      "use of term "word" when talking about header structure"
2898    </t>
2899  </list>
2900</t>
2901<t>
2902  Partly resolved issues:
2903  <list style="symbols"> 
2904    <t>
2905      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/196"/>:
2906      "Term for the requested resource's URI"
2907    </t>
2908  </list>
2909</t>
2910</section>
2911
2912<section title="Since draft-ietf-httpbis-p3-payload-10" anchor="changes.since.10">
2913<t>
2914  Closed issues:
2915  <list style="symbols"> 
2916    <t>
2917      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
2918      "Clarify 'Requested Variant'"
2919    </t>
2920    <t>
2921      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>:
2922      "Content-Location isn't special"
2923    </t>
2924    <t>
2925      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/90"/>:
2926      "Delimiting messages with multipart/byteranges"
2927    </t>
2928    <t>
2929      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
2930      "Clarify entity / representation / variant terminology"
2931    </t>
2932    <t>
2933      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/136"/>:
2934      "confusing req. language for Content-Location"
2935    </t>
2936    <t>
2937      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/167"/>:
2938      "Content-Location on 304 responses"
2939    </t>
2940    <t>
2941      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/183"/>:
2942      "'requested resource' in content-encoding definition"
2943    </t>
2944    <t>
2945      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
2946      "consider removing the 'changes from 2068' sections"
2947    </t>
2948  </list>
2949</t>
2950<t>
2951  Partly resolved issues:
2952  <list style="symbols"> 
2953    <t>
2954      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>:
2955      "Content-MD5 and partial responses"
2956    </t>
2957  </list>
2958</t>
2959</section>
2960
2961<section title="Since draft-ietf-httpbis-p3-payload-11" anchor="changes.since.11">
2962<t>
2963  Closed issues:
2964  <list style="symbols"> 
2965    <t>
2966      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/123"/>:
2967      "Factor out Content-Disposition"
2968    </t>
2969  </list>
2970</t>
2971</section>
2972
2973<section title="Since draft-ietf-httpbis-p3-payload-12" anchor="changes.since.12">
2974<t>
2975  Closed issues:
2976  <list style="symbols"> 
2977    <t>
2978      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
2979      "Header Classification"
2980    </t>
2981    <t>
2982      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
2983      "untangle ABNFs for header fields"
2984    </t>
2985    <t>
2986      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/277"/>:
2987      "potentially misleading MAY in media-type def"
2988    </t>
2989  </list>
2990</t>
2991</section>
2992
2993<section title="Since draft-ietf-httpbis-p3-payload-13" anchor="changes.since.13">
2994<t>
2995  Closed issues:
2996  <list style="symbols"> 
2997    <t>
2998      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/20"/>:
2999      "Default charsets for text media types"
3000    </t>
3001    <t>
3002      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>:
3003      "Content-MD5 and partial responses"
3004    </t>
3005    <t>
3006      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
3007      "untangle ABNFs for header fields"
3008    </t>
3009    <t>
3010      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/281"/>:
3011      "confusing undefined parameter in media range example"
3012    </t>
3013  </list>
3014</t>
3015</section>
3016
3017<section title="Since draft-ietf-httpbis-p3-payload-14" anchor="changes.since.14">
3018<t>
3019  None.
3020</t>
3021</section>
3022
3023<section title="Since draft-ietf-httpbis-p3-payload-15" anchor="changes.since.15">
3024<t>
3025  Closed issues:
3026  <list style="symbols"> 
3027    <t>
3028      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/285"/>:
3029      "Strength of requirements on Accept re: 406"
3030    </t>
3031  </list>
3032</t>
3033</section>
3034
3035<section title="Since draft-ietf-httpbis-p3-payload-16" anchor="changes.since.16">
3036<t>
3037  None yet.
3038</t>
3039</section>
3040
3041</section>
3042
3043</back>
3044</rfc>
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