source: draft-ietf-httpbis/latest/p3-payload.xml @ 1373

Last change on this file since 1373 was 1373, checked in by julian.reschke@…, 8 years ago

align sbatracts and put a paragraph break inside for readability

  • Property svn:eol-style set to native
File size: 123.0 KB
Line 
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 "August">
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 caching-neg-resp         "<xref target='Part6' x:rel='#caching.negotiated.responses' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY header-transfer-encoding "<xref target='Part1' x:rel='#header.transfer-encoding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY header-content-length    "<xref target='Part1' x:rel='#header.content-length' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY header-content-range     "<xref target='Part5' x:rel='#header.content-range' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY header-expires           "<xref target='Part6' x:rel='#header.expires' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY header-last-modified     "<xref target='Part4' x:rel='#header.last-modified' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY header-user-agent        "<xref target='Part2' x:rel='#header.user-agent' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29  <!ENTITY header-vary              "<xref target='Part6' x:rel='#header.vary' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
30  <!ENTITY message-body             "<xref target='Part1' x:rel='#message.body' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
31  <!ENTITY multipart-byteranges     "<xref target='Part5' x:rel='#internet.media.type.multipart.byteranges' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
32  <!ENTITY full-date                "<xref target='Part1' x:rel='#date.time.formats.full.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
33  <!ENTITY qvalue                   "<xref target='Part1' x:rel='#quality.values' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
34  <!ENTITY uri                      "<xref target='Part1' x:rel='#uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
35  <!ENTITY effective-request-uri    "<xref target='Part1' x:rel='#effective.request.uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
36  <!ENTITY compression-codings      "<xref target='Part1' x:rel='#compression.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
37  <!ENTITY transfer-codings         "<xref target='Part1' x:rel='#transfer.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
38  <!ENTITY compress-coding          "<xref target='Part1' x:rel='#compress.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
39  <!ENTITY deflate-coding           "<xref target='Part1' x:rel='#deflate.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
40  <!ENTITY gzip-coding              "<xref target='Part1' x:rel='#gzip.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
41  <!ENTITY response-representation  "<xref target='Part2' x:rel='#identifying.response.associated.with.representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
42]>
43<?rfc toc="yes" ?>
44<?rfc symrefs="yes" ?>
45<?rfc sortrefs="yes" ?>
46<?rfc compact="yes"?>
47<?rfc subcompact="no" ?>
48<?rfc linkmailto="no" ?>
49<?rfc editing="no" ?>
50<?rfc comments="yes"?>
51<?rfc inline="yes"?>
52<?rfc rfcedstyle="yes"?>
53<?rfc-ext allow-markup-in-artwork="yes" ?>
54<?rfc-ext include-references-in-index="yes" ?>
55<rfc obsoletes="2616" category="std" x:maturity-level="draft"
56     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p3-payload-&ID-VERSION;"
57     xmlns:x='http://purl.org/net/xml2rfc/ext'>
58<front>
59
60  <title abbrev="HTTP/1.1, Part 3">HTTP/1.1, part 3: Message Payload and Content Negotiation</title>
61
62  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
63    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
64    <address>
65      <postal>
66        <street>345 Park Ave</street>
67        <city>San Jose</city>
68        <region>CA</region>
69        <code>95110</code>
70        <country>USA</country>
71      </postal>
72      <email>fielding@gbiv.com</email>
73      <uri>http://roy.gbiv.com/</uri>
74    </address>
75  </author>
76
77  <author initials="J." surname="Gettys" fullname="Jim Gettys">
78    <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
79    <address>
80      <postal>
81        <street>21 Oak Knoll Road</street>
82        <city>Carlisle</city>
83        <region>MA</region>
84        <code>01741</code>
85        <country>USA</country>
86      </postal>
87      <email>jg@freedesktop.org</email>
88      <uri>http://gettys.wordpress.com/</uri>
89    </address>
90  </author>
91 
92  <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
93    <organization abbrev="HP">Hewlett-Packard Company</organization>
94    <address>
95      <postal>
96        <street>HP Labs, Large Scale Systems Group</street>
97        <street>1501 Page Mill Road, MS 1177</street>
98        <city>Palo Alto</city>
99        <region>CA</region>
100        <code>94304</code>
101        <country>USA</country>
102      </postal>
103      <email>JeffMogul@acm.org</email>
104    </address>
105  </author>
106
107  <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
108    <organization abbrev="Microsoft">Microsoft Corporation</organization>
109    <address>
110      <postal>
111        <street>1 Microsoft Way</street>
112        <city>Redmond</city>
113        <region>WA</region>
114        <code>98052</code>
115        <country>USA</country>
116      </postal>
117      <email>henrikn@microsoft.com</email>
118    </address>
119  </author>
120
121  <author initials="L." surname="Masinter" fullname="Larry Masinter">
122    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
123    <address>
124      <postal>
125        <street>345 Park Ave</street>
126        <city>San Jose</city>
127        <region>CA</region>
128        <code>95110</code>
129        <country>USA</country>
130      </postal>
131      <email>LMM@acm.org</email>
132      <uri>http://larry.masinter.net/</uri>
133    </address>
134  </author>
135 
136  <author initials="P." surname="Leach" fullname="Paul J. Leach">
137    <organization abbrev="Microsoft">Microsoft Corporation</organization>
138    <address>
139      <postal>
140        <street>1 Microsoft Way</street>
141        <city>Redmond</city>
142        <region>WA</region>
143        <code>98052</code>
144      </postal>
145      <email>paulle@microsoft.com</email>
146    </address>
147  </author>
148   
149  <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
150    <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
151    <address>
152      <postal>
153        <street>MIT Computer Science and Artificial Intelligence Laboratory</street>
154        <street>The Stata Center, Building 32</street>
155        <street>32 Vassar Street</street>
156        <city>Cambridge</city>
157        <region>MA</region>
158        <code>02139</code>
159        <country>USA</country>
160      </postal>
161      <email>timbl@w3.org</email>
162      <uri>http://www.w3.org/People/Berners-Lee/</uri>
163    </address>
164  </author>
165
166  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
167    <organization abbrev="W3C">World Wide Web Consortium</organization>
168    <address>
169      <postal>
170        <street>W3C / ERCIM</street>
171        <street>2004, rte des Lucioles</street>
172        <city>Sophia-Antipolis</city>
173        <region>AM</region>
174        <code>06902</code>
175        <country>France</country>
176      </postal>
177      <email>ylafon@w3.org</email>
178      <uri>http://www.raubacapeu.net/people/yves/</uri>
179    </address>
180  </author>
181
182  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
183    <organization abbrev="greenbytes">greenbytes GmbH</organization>
184    <address>
185      <postal>
186        <street>Hafenweg 16</street>
187        <city>Muenster</city><region>NW</region><code>48155</code>
188        <country>Germany</country>
189      </postal>
190      <phone>+49 251 2807760</phone>
191      <facsimile>+49 251 2807761</facsimile>
192      <email>julian.reschke@greenbytes.de</email>
193      <uri>http://greenbytes.de/tech/webdav/</uri>
194    </address>
195  </author>
196
197  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
198  <workgroup>HTTPbis Working Group</workgroup>
199
200<abstract>
201<t>
202   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
203   distributed, collaborative, hypertext information systems. HTTP has been in
204   use by the World Wide Web global information initiative since 1990. This
205   document is Part 3 of the seven-part specification that defines the protocol
206   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
207</t>
208<t>
209   Part 3 defines HTTP message content, metadata, and content negotiation.
210</t>
211</abstract>
212
213<note title="Editorial Note (To be removed by RFC Editor)">
214  <t>
215    Discussion of this draft should take place on the HTTPBIS working group
216    mailing list (ietf-http-wg@w3.org), which is archived at
217    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
218  </t>
219  <t>
220    The current issues list is at
221    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
222    documents (including fancy diffs) can be found at
223    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
224  </t>
225  <t>
226    The changes in this draft are summarized in <xref target="changes.since.15"/>.
227  </t>
228</note>
229</front>
230<middle>
231<section title="Introduction" anchor="introduction">
232<t>
233   This document defines HTTP/1.1 message payloads (a.k.a., content), the
234   associated metadata header fields that define how the payload is intended
235   to be interpreted by a recipient, the request header fields that
236   might influence content selection, and the various selection algorithms
237   that are collectively referred to as HTTP content negotiation.
238</t>
239<t>
240   This document is currently disorganized in order to minimize the changes
241   between drafts and enable reviewers to see the smaller errata changes.
242   A future draft will reorganize the sections to better reflect the content.
243   In particular, the sections on entities will be renamed payload and moved
244   to the first half of the document, while the sections on content negotiation
245   and associated request header fields will be moved to the second half.  The
246   current mess reflects how widely dispersed these topics and associated
247   requirements had become in <xref target="RFC2616"/>.
248</t>
249
250<section title="Terminology" anchor="terminology">
251<t>
252   This specification uses a number of terms to refer to the roles
253   played by participants in, and objects of, the HTTP communication.
254</t>
255<t>
256  <iref item="content negotiation"/>
257  <x:dfn>content negotiation</x:dfn>
258  <list>
259    <t>
260      The mechanism for selecting the appropriate representation when
261      servicing a request. The representation in any response
262      can be negotiated (including error responses).
263    </t>
264  </list>
265</t>
266</section>
267
268<section title="Requirements" anchor="intro.requirements">
269<t>
270   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
271   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
272   document are to be interpreted as described in <xref target="RFC2119"/>.
273</t>
274<t>
275   An implementation is not compliant if it fails to satisfy one or more
276   of the "MUST" or "REQUIRED" level requirements for the protocols it
277   implements. An implementation that satisfies all the "MUST" or "REQUIRED"
278   level and all the "SHOULD" level requirements for its protocols is said
279   to be "unconditionally compliant"; one that satisfies all the "MUST"
280   level requirements but not all the "SHOULD" level requirements for its
281   protocols is said to be "conditionally compliant".
282</t>
283</section>
284
285<section title="Syntax Notation" anchor="notation">
286  <x:anchor-alias value="ALPHA"/>
287  <x:anchor-alias value="CR"/>
288  <x:anchor-alias value="DIGIT"/>
289  <x:anchor-alias value="LF"/>
290  <x:anchor-alias value="OCTET"/>
291  <x:anchor-alias value="VCHAR"/>
292  <x:anchor-alias value="WSP"/>
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),
306  VCHAR (any visible USASCII character),
307  and WSP (whitespace).
308</t>
309
310<section title="Core Rules" anchor="core.rules">
311  <x:anchor-alias value="token"/>
312  <x:anchor-alias value="word"/>
313  <x:anchor-alias value="OWS"/>
314<t>
315  The core rules below are defined in &basic-rules;:
316</t>
317<figure><artwork type="abnf2616">
318  <x:ref>token</x:ref>          = &lt;token, defined in &basic-rules;&gt;
319  <x:ref>word</x:ref>           = &lt;word, defined in &basic-rules;&gt;
320  <x:ref>OWS</x:ref>            = &lt;OWS, defined in &basic-rules;&gt;
321</artwork></figure>
322</section>
323
324<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
325  <x:anchor-alias value="absolute-URI"/>
326  <x:anchor-alias value="partial-URI"/>
327  <x:anchor-alias value="qvalue"/>
328<t>
329  The ABNF rules below are defined in other parts:
330</t>
331<figure><!--Part1--><artwork type="abnf2616">
332  <x:ref>absolute-URI</x:ref>   = &lt;absolute-URI, defined in &uri;&gt;
333  <x:ref>partial-URI</x:ref>    = &lt;partial-URI, defined in &uri;&gt;
334  <x:ref>qvalue</x:ref>         = &lt;qvalue, defined in &qvalue;&gt;
335</artwork></figure>
336</section>
337
338</section>
339
340</section>
341
342<section title="Protocol Parameters" anchor="protocol.parameters">
343
344<section title="Character Encodings (charset)" anchor="character.sets">
345<t>
346   HTTP uses charset names to indicate the character encoding of a
347   textual representation.
348</t>
349<t anchor="rule.charset">
350  <x:anchor-alias value="charset"/>
351   A character encoding is identified by a case-insensitive token. The
352   complete set of tokens is defined by the IANA Character Set registry
353   (<eref target="http://www.iana.org/assignments/character-sets"/>).
354</t>
355<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="charset"/>
356  <x:ref>charset</x:ref> = <x:ref>token</x:ref>
357</artwork></figure>
358<t>
359   Although HTTP allows an arbitrary token to be used as a charset
360   value, any token that has a predefined value within the IANA
361   Character Set registry &MUST; represent the character encoding defined
362   by that registry. Applications &SHOULD; limit their use of character
363   encodings to those defined within the IANA registry.
364</t>
365<t>
366   HTTP uses charset in two contexts: within an Accept-Charset request
367   header field (in which the charset value is an unquoted token) and as the
368   value of a parameter in a Content-Type header field (within a request or
369   response), in which case the parameter value of the charset parameter
370   can be quoted.
371</t>
372<t>
373   Implementors need to be aware of IETF character set requirements <xref target="RFC3629"/>
374   <xref target="RFC2277"/>.
375</t>
376</section>
377
378<section title="Content Codings" anchor="content.codings">
379  <x:anchor-alias value="content-coding"/>
380<t>
381   Content coding values indicate an encoding transformation that has
382   been or can be applied to a representation. Content codings are primarily
383   used to allow a representation to be compressed or otherwise usefully
384   transformed without losing the identity of its underlying media type
385   and without loss of information. Frequently, the representation is stored in
386   coded form, transmitted directly, and only decoded by the recipient.
387</t>
388<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="content-coding"/>
389  <x:ref>content-coding</x:ref>   = <x:ref>token</x:ref>
390</artwork></figure>
391<t>
392   All content-coding values are case-insensitive. HTTP/1.1 uses
393   content-coding values in the Accept-Encoding (<xref target="header.accept-encoding"/>) and
394   Content-Encoding (<xref target="header.content-encoding"/>) header fields. Although the value
395   describes the content-coding, what is more important is that it
396   indicates what decoding mechanism will be required to remove the
397   encoding.
398</t>
399<t>
400   compress<iref item="compress (Coding Format)"/><iref item="Coding Format" subitem="compress"/>
401  <list>
402    <t>
403      See &compress-coding;.
404    </t>
405  </list>
406</t>
407<t>
408   deflate<iref item="deflate (Coding Format)"/><iref item="Coding Format" subitem="deflate"/>
409  <list>
410    <t>
411      See &deflate-coding;.
412    </t>
413  </list>
414</t>
415<t>
416   gzip<iref item="gzip (Coding Format)"/><iref item="Coding Format" subitem="gzip"/>
417  <list>
418    <t>
419      See &gzip-coding;.
420    </t>
421  </list>
422</t>
423<t>
424   identity<iref item="identity (Coding Format)"/><iref item="Coding Format" subitem="identity"/>
425  <list><t>
426        The default (identity) encoding; the use of no transformation
427        whatsoever. This content-coding is used only in the Accept-Encoding
428        header field, and &SHOULD-NOT;  be used in the Content-Encoding
429        header field.
430  </t></list>
431</t>
432
433<section title="Content Coding Registry" anchor="content.coding.registry">
434<t>
435   The HTTP Content Coding Registry defines the name space for the content
436   coding names.
437</t>
438<t>
439   Registrations &MUST; include the following fields:
440   <list style="symbols">
441     <t>Name</t>
442     <t>Description</t>
443     <t>Pointer to specification text</t>
444   </list>
445</t>
446<t>
447   Names of content codings &MUST-NOT; overlap with names of transfer codings
448   (&transfer-codings;), unless the encoding transformation is identical (as it
449   is the case for the compression codings defined in
450   &compression-codings;).
451</t>
452<t>
453   Values to be added to this name space require a specification
454   (see "Specification Required" in
455   <xref target="RFC5226" x:fmt="of" x:sec="4.1"/>), and &MUST;
456   conform to the purpose of content coding defined in this section.
457</t>
458<t>
459   The registry itself is maintained at
460   <eref target="http://www.iana.org/assignments/http-parameters"/>.
461</t>
462</section>
463
464</section>
465
466<section title="Media Types" anchor="media.types">
467  <x:anchor-alias value="media-type"/>
468  <x:anchor-alias value="type"/>
469  <x:anchor-alias value="subtype"/>
470<t>
471   HTTP uses Internet Media Types <xref target="RFC2046"/> in the Content-Type (<xref target="header.content-type"/>)
472   and Accept (<xref target="header.accept"/>) header fields in order to provide
473   open and extensible data typing and type negotiation.
474</t>
475<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"/>
476  <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> )
477  <x:ref>type</x:ref>       = <x:ref>token</x:ref>
478  <x:ref>subtype</x:ref>    = <x:ref>token</x:ref>
479</artwork></figure>
480<t anchor="rule.parameter">
481  <x:anchor-alias value="attribute"/>
482  <x:anchor-alias value="parameter"/>
483  <x:anchor-alias value="value"/>
484   The type/subtype &MAY; be followed by parameters in the form of
485   attribute/value pairs.
486</t>
487<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"/>
488  <x:ref>parameter</x:ref>      = <x:ref>attribute</x:ref> "=" <x:ref>value</x:ref>
489  <x:ref>attribute</x:ref>      = <x:ref>token</x:ref>
490  <x:ref>value</x:ref>          = <x:ref>word</x:ref>
491</artwork></figure>
492<t>
493   The type, subtype, and parameter attribute names are case-insensitive.
494   Parameter values might or might not be case-sensitive, depending on the
495   semantics of the parameter name.  The presence or absence of a parameter might
496   be significant to the processing of a media-type, depending on its
497   definition within the media type registry.
498</t>
499<t>
500   A parameter value that matches the <x:ref>token</x:ref> production can be
501   transmitted as either a token or within a quoted-string. The quoted and
502   unquoted values are equivalent.
503</t>
504<t>
505   Note that some older HTTP applications do not recognize media type
506   parameters. When sending data to older HTTP applications,
507   implementations &SHOULD; only use media type parameters when they are
508   required by that type/subtype definition.
509</t>
510<t>
511   Media-type values are registered with the Internet Assigned Number
512   Authority (IANA). The media type registration process is
513   outlined in <xref target="RFC4288"/>. Use of non-registered media types is
514   discouraged.
515</t>
516
517<section title="Canonicalization and Text Defaults" anchor="canonicalization.and.text.defaults">
518<t>
519   Internet media types are registered with a canonical form. A
520   representation transferred via HTTP messages &MUST; be in the
521   appropriate canonical form prior to its transmission except for
522   "text" types, as defined in the next paragraph.
523</t>
524<t>
525   When in canonical form, media subtypes of the "text" type use CRLF as
526   the text line break. HTTP relaxes this requirement and allows the
527   transport of text media with plain CR or LF alone representing a line
528   break when it is done consistently for an entire representation. HTTP
529   applications &MUST; accept CRLF, bare CR, and bare LF as indicating
530   a line break in text media received via HTTP. In
531   addition, if the text is in a character encoding that does not
532   use octets 13 and 10 for CR and LF respectively, as is the case for
533   some multi-byte character encodings, HTTP allows the use of whatever octet
534   sequences are defined by that character encoding to represent the
535   equivalent of CR and LF for line breaks. This flexibility regarding
536   line breaks applies only to text media in the payload body; a bare CR
537   or LF &MUST-NOT; be substituted for CRLF within any of the HTTP control
538   structures (such as header fields and multipart boundaries).
539</t>
540<t>
541   If a representation is encoded with a content-coding, the underlying
542   data &MUST; be in a form defined above prior to being encoded.
543</t>
544</section>
545
546<section title="Multipart Types" anchor="multipart.types">
547<t>
548   MIME provides for a number of "multipart" types &mdash; encapsulations of
549   one or more representations within a single message-body. All multipart
550   types share a common syntax, as defined in <xref target="RFC2046" x:sec="5.1.1" x:fmt="of"/>,
551   and &MUST; include a boundary parameter as part of the media type
552   value. The message body is itself a protocol element and &MUST;
553   therefore use only CRLF to represent line breaks between body-parts.
554</t>
555<t>
556   In general, HTTP treats a multipart message-body no differently than
557   any other media type: strictly as payload.  HTTP does not use the
558   multipart boundary as an indicator of message-body length.
559   <!-- jre: re-insert removed text pointing to caching? -->
560   In all other respects, an HTTP user agent &SHOULD; follow the same or similar
561   behavior as a MIME user agent would upon receipt of a multipart type.
562   The MIME header fields within each body-part of a multipart message-body
563   do not have any significance to HTTP beyond that defined by
564   their MIME semantics.
565</t>
566<t>
567   If an application receives an unrecognized multipart subtype, the
568   application &MUST; treat it as being equivalent to "multipart/mixed".
569</t>
570<x:note>
571  <t>
572    <x:h>Note:</x:h> The "multipart/form-data" type has been specifically defined
573    for carrying form data suitable for processing via the POST
574    request method, as described in <xref target="RFC2388"/>.
575  </t>
576</x:note>
577</section>
578</section>
579
580<section title="Language Tags" anchor="language.tags">
581  <x:anchor-alias value="language-tag"/>
582<t>
583   A language tag, as defined in <xref target="RFC5646"/>, identifies a
584   natural language spoken, written, or otherwise conveyed by human beings for
585   communication of information to other human beings. Computer languages are
586   explicitly excluded. HTTP uses language tags within the Accept-Language and
587   Content-Language fields.
588</t>
589<t>
590   In summary, a language tag is composed of one or more parts: A primary
591   language subtag followed by a possibly empty series of subtags:
592</t>
593<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="language-tag"/>
594  <x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in <xref target="RFC5646" x:sec="2.1"/>&gt;
595</artwork></figure>
596<t>
597   White space is not allowed within the tag and all tags are case-insensitive.
598   The name space of language subtags is administered by the IANA (see
599   <eref target="http://www.iana.org/assignments/language-subtag-registry"/>).
600</t>
601<figure>
602  <preamble>Example tags include:</preamble>
603<artwork type="example">
604  en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN
605</artwork>
606</figure>
607<t>
608   See <xref target="RFC5646"/> for further information.
609</t>
610</section>
611</section>
612
613<section title="Payload" anchor="payload">
614<t>
615   HTTP messages &MAY; transfer a payload if not otherwise restricted by
616   the request method or response status code.  The payload consists of
617   metadata, in the form of header fields, and data, in the form of the
618   sequence of octets in the message-body after any transfer-coding has
619   been decoded.
620</t>
621<iref item="payload"/>
622<t>   
623   A "<x:dfn>payload</x:dfn>" in HTTP is always a partial or complete
624   representation of some resource.  We use separate terms for payload
625   and representation because some messages contain only the associated
626   representation's header fields (e.g., responses to HEAD) or only some
627   part(s) of the representation (e.g., the 206 status code).
628</t>
629<section title="Payload Header Fields" anchor="payload.header.fields">
630  <x:anchor-alias value="payload-header"/>
631<t>
632   HTTP header fields that specifically define the payload, rather than the
633   associated representation, are referred to as "payload header fields".
634   The following payload header fields are defined by HTTP/1.1:
635</t>
636<texttable align="left">
637  <ttcol>Header Field Name</ttcol>
638  <ttcol>Defined in...</ttcol>
639
640  <c>Content-Length</c> <c>&header-content-length;</c>
641  <c>Content-Range</c> <c>&header-content-range;</c>
642</texttable>
643</section>
644
645<section title="Payload Body" anchor="payload.body">
646  <x:anchor-alias value="payload-body"/>
647<t>
648   A payload body is only present in a message when a message-body is
649   present, as described in &message-body;. The payload body is obtained
650   from the message-body by decoding any Transfer-Encoding that might
651   have been applied to ensure safe and proper transfer of the message.
652</t>
653</section>
654</section>
655
656<section title="Representation" anchor="representation">
657<iref item="representation"/>
658<t>
659   A "<x:dfn>representation</x:dfn>" is information in a format that can be readily
660   communicated from one party to another.  A resource representation
661   is information that reflects the state of that resource, as observed
662   at some point in the past (e.g., in a response to GET) or to be
663   desired at some point in the future (e.g., in a PUT request).
664</t>
665<t>
666   Most, but not all, representations transferred via HTTP are intended
667   to be a representation of the target resource (the resource identified
668   by the effective request URI).  The precise semantics of a representation
669   are determined by the type of message (request or response), the request
670   method, the response status code, and the representation metadata.
671   For example, the above semantic is true for the representation in any
672   200 (OK) response to GET and for the representation in any PUT request.
673   A 200 response to PUT, in contrast, contains either a representation
674   that describes the successful action or a representation of the target
675   resource, with the latter indicated by a Content-Location header field
676   with the same value as the effective request URI.  Likewise, response
677   messages with an error status code usually contain a representation that
678   describes the error and what next steps are suggested for resolving it.
679</t>
680
681<section title="Representation Header Fields" anchor="representation.header.fields">
682  <x:anchor-alias value="representation-header"/>
683<t>
684   Representation header fields define metadata about the representation data
685   enclosed in the message-body or, if no message-body is present, about
686   the representation that would have been transferred in a 200 response
687   to a simultaneous GET request with the same effective request URI.
688</t>
689<t>
690   The following header fields are defined as representation metadata:
691</t>
692<texttable align="left">
693  <ttcol>Header Field Name</ttcol>
694  <ttcol>Defined in...</ttcol>
695
696  <c>Content-Encoding</c> <c><xref target="header.content-encoding"/></c>
697  <c>Content-Language</c> <c><xref target="header.content-language"/></c>
698  <c>Content-Location</c> <c><xref target="header.content-location"/></c>
699  <c>Content-Type</c> <c><xref target="header.content-type"/></c>
700  <c>Expires</c> <c>&header-expires;</c>
701  <c>Last-Modified</c> <c>&header-last-modified;</c>
702</texttable>
703</section>
704
705<section title="Representation Data" anchor="representation.data">
706  <x:anchor-alias value="representation-data"/>
707<t>
708   The representation body associated with an HTTP message is
709   either provided as the payload body of the message or
710   referred to by the message semantics and the effective request
711   URI.  The representation data is in a format and encoding defined by
712   the representation metadata header fields.
713</t>
714<t>
715   The data type of the representation data
716   is determined via the header fields Content-Type and Content-Encoding.
717   These define a two-layer, ordered encoding model:
718</t>
719<figure><artwork type="example">
720  representation-data := Content-Encoding( Content-Type( bits ) )
721</artwork></figure>
722<t>
723   Content-Type specifies the media type of the underlying data, which
724   defines both the data format and how that data &SHOULD; be processed
725   by the recipient (within the scope of the request method semantics).
726   Any HTTP/1.1 message containing a payload body &SHOULD; include a
727   Content-Type header field defining the media type of the associated
728   representation unless that metadata is unknown to the sender.
729   If the Content-Type header field is not present, it indicates that
730   the sender does not know the media type of the representation;
731   recipients &MAY; either assume that the media type is
732   "application/octet-stream" (<xref target="RFC2046" x:fmt="," x:sec="4.5.1"/>)
733   or examine the content to determine its type.
734</t>
735<t>
736   In practice, resource owners do not always properly configure their origin
737   server to provide the correct Content-Type for a given representation,
738   with the result that some clients will examine a response body's content
739   and override the specified type.
740   Clients that do so risk drawing incorrect conclusions, which might expose
741   additional security risks (e.g., "privilege escalation").  Furthermore,
742   it is impossible to determine the sender's intent by examining the data
743   format: many data formats match multiple media types that differ only in
744   processing semantics.  Implementers are encouraged to provide a means of
745   disabling such "content sniffing" when it is used.
746</t>
747<t>
748   Content-Encoding is used to indicate any additional content
749   codings applied to the data, usually for the purpose of data
750   compression, that are a property of the representation.  If
751   Content-Encoding is not present, then there is no additional
752   encoding beyond that defined by the Content-Type.
753</t>
754</section>
755</section>
756
757<section title="Content Negotiation" anchor="content.negotiation">
758<t>
759   HTTP responses include a representation which contains information for
760   interpretation, whether by a human user or for further processing.
761   Often, the server has different ways of representing the
762   same information; for example, in different formats, languages,
763   or using different character encodings.
764</t>
765<t>
766   HTTP clients and their users might have different or variable
767   capabilities, characteristics or preferences which would influence
768   which representation, among those available from the server,
769   would be best for the server to deliver. For this reason, HTTP
770   provides mechanisms for "content negotiation" &mdash; a process of
771   allowing selection of a representation of a given resource,
772   when more than one is available.
773</t>
774<t>
775   This specification defines two patterns of content negotiation;
776   "server-driven", where the server selects the representation based
777   upon the client's stated preferences, and "agent-driven" negotiation,
778   where the server provides a list of representations for the client to
779   choose from, based upon their metadata. In addition,  there are
780   other patterns: some applications use an "active content" pattern,
781   where the server returns active content which runs on the client
782   and, based on client available parameters, selects additional
783   resources to invoke. "Transparent Content Negotiation" (<xref target="RFC2295"/>)
784   has also been proposed.
785</t>
786<t>
787   These patterns are all widely used, and have trade-offs in applicability
788   and practicality. In particular, when the number of preferences or
789   capabilities to be expressed by a client are large (such as when many
790   different formats are supported by a user-agent), server-driven
791   negotiation becomes unwieldy, and might not be appropriate. Conversely,
792   when the number of representations to choose from is very large,
793   agent-driven negotiation might not be appropriate.
794</t>
795<t>
796   Note that in all cases, the supplier of representations has the
797   responsibility for determining which representations might be
798   considered to be the "same information".
799</t>
800
801<section title="Server-driven Negotiation" anchor="server-driven.negotiation">
802<t>
803   If the selection of the best representation for a response is made by
804   an algorithm located at the server, it is called server-driven
805   negotiation. Selection is based on the available representations of
806   the response (the dimensions over which it can vary; e.g., language,
807   content-coding, etc.) and the contents of particular header fields in
808   the request message or on other information pertaining to the request
809   (such as the network address of the client).
810</t>
811<t>
812   Server-driven negotiation is advantageous when the algorithm for
813   selecting from among the available representations is difficult to
814   describe to the user agent, or when the server desires to send its
815   "best guess" to the client along with the first response (hoping to
816   avoid the round-trip delay of a subsequent request if the "best
817   guess" is good enough for the user). In order to improve the server's
818   guess, the user agent &MAY; include request header fields (Accept,
819   Accept-Language, Accept-Encoding, etc.) which describe its
820   preferences for such a response.
821</t>
822<t>
823   Server-driven negotiation has disadvantages:
824  <list style="numbers">
825    <t>
826         It is impossible for the server to accurately determine what
827         might be "best" for any given user, since that would require
828         complete knowledge of both the capabilities of the user agent
829         and the intended use for the response (e.g., does the user want
830         to view it on screen or print it on paper?).
831    </t>
832    <t>
833         Having the user agent describe its capabilities in every
834         request can be both very inefficient (given that only a small
835         percentage of responses have multiple representations) and a
836         potential violation of the user's privacy.
837    </t>
838    <t>
839         It complicates the implementation of an origin server and the
840         algorithms for generating responses to a request.
841    </t>
842    <t>
843         It might limit a public cache's ability to use the same response
844         for multiple user's requests.
845    </t>
846  </list>
847</t>
848<t>
849   Server-driven negotiation allows the user agent to specify its preferences,
850   but it cannot expect responses to always honour them. For example, the origin
851   server might not implement server-driven negotiation, or it might decide that
852   sending a response that doesn't conform to them is better than sending a 406
853   (Not Acceptable) response.
854</t>
855<t>
856   Many of the mechanisms for expressing preferences use quality values to
857   declare relative preference. See &qvalue; for more information.
858</t>
859<t>
860   HTTP/1.1 includes the following header fields for enabling
861   server-driven negotiation through description of user agent
862   capabilities and user preferences: Accept (<xref target="header.accept"/>), Accept-Charset
863   (<xref target="header.accept-charset"/>), Accept-Encoding (<xref target="header.accept-encoding"/>), Accept-Language
864   (<xref target="header.accept-language"/>), and User-Agent (&header-user-agent;).
865   However, an origin server is not limited to these dimensions and &MAY; vary
866   the response based on any aspect of the request, including aspects
867   of the connection (e.g., IP address) or information within extension
868   header fields not defined by this specification.
869</t>
870<x:note>
871  <t>
872    <x:h>Note:</x:h> In practice, User-Agent based negotiation is fragile,
873    because new clients might not be recognized.
874  </t>
875</x:note>
876<t>
877   The Vary header field (&header-vary;) can be used to express the parameters the
878   server uses to select a representation that is subject to server-driven
879   negotiation.
880</t>
881</section>
882
883<section title="Agent-driven Negotiation" anchor="agent-driven.negotiation">
884<t>
885   With agent-driven negotiation, selection of the best representation
886   for a response is performed by the user agent after receiving an
887   initial response from the origin server. Selection is based on a list
888   of the available representations of the response included within the
889   header fields or body of the initial response, with each
890   representation identified by its own URI. Selection from among the
891   representations can be performed automatically (if the user agent is
892   capable of doing so) or manually by the user selecting from a
893   generated (possibly hypertext) menu.
894</t>
895<t>
896   Agent-driven negotiation is advantageous when the response would vary
897   over commonly-used dimensions (such as type, language, or encoding),
898   when the origin server is unable to determine a user agent's
899   capabilities from examining the request, and generally when public
900   caches are used to distribute server load and reduce network usage.
901</t>
902<t>
903   Agent-driven negotiation suffers from the disadvantage of needing a
904   second request to obtain the best alternate representation. This
905   second request is only efficient when caching is used. In addition,
906   this specification does not define any mechanism for supporting
907   automatic selection, though it also does not prevent any such
908   mechanism from being developed as an extension and used within
909   HTTP/1.1.
910</t>
911<t>
912   This specification defines the 300 (Multiple Choices) and 406 (Not Acceptable)
913   status codes for enabling agent-driven negotiation when the server is
914   unwilling or unable to provide a varying response using server-driven
915   negotiation.
916</t>
917</section>
918</section>
919
920<section title="Header Field Definitions" anchor="header.fields">
921<t>
922   This section defines the syntax and semantics of HTTP/1.1 header fields
923   related to the payload of messages.
924</t>
925
926<section title="Accept" anchor="header.accept">
927  <iref primary="true" item="Accept header field" x:for-anchor=""/>
928  <iref primary="true" item="Header Fields" subitem="Accept" x:for-anchor=""/>
929  <x:anchor-alias value="Accept"/>
930  <x:anchor-alias value="accept-ext"/>
931  <x:anchor-alias value="accept-params"/>
932  <x:anchor-alias value="media-range"/>
933<t>
934   The "Accept" header field can be used by user agents to specify
935   response media types that are acceptable. Accept header fields can be used to
936   indicate that the request is specifically limited to a small set of desired
937   types, as in the case of a request for an in-line image.
938</t>
939<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"/>
940  <x:ref>Accept</x:ref> = #( <x:ref>media-range</x:ref> [ <x:ref>accept-params</x:ref> ] )
941 
942  <x:ref>media-range</x:ref>    = ( "*/*"
943                   / ( <x:ref>type</x:ref> "/" "*" )
944                   / ( <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> )
945                   ) *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> )
946  <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> )
947  <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> ]
948</artwork></figure>
949<t>
950   The asterisk "*" character is used to group media types into ranges,
951   with "*/*" indicating all media types and "type/*" indicating all
952   subtypes of that type. The media-range &MAY; include media type
953   parameters that are applicable to that range.
954</t>
955<t>
956   Each media-range &MAY; be followed by one or more accept-params,
957   beginning with the "q" parameter for indicating a relative quality
958   factor. The first "q" parameter (if any) separates the media-range
959   parameter(s) from the accept-params. Quality factors allow the user
960   or user agent to indicate the relative degree of preference for that
961   media-range, using the qvalue scale from 0 to 1 (&qvalue;). The
962   default value is q=1.
963</t>
964<x:note>
965  <t>
966    <x:h>Note:</x:h> Use of the "q" parameter name to separate media type
967    parameters from Accept extension parameters is due to historical
968    practice. Although this prevents any media type parameter named
969    "q" from being used with a media range, such an event is believed
970    to be unlikely given the lack of any "q" parameters in the IANA
971    media type registry and the rare usage of any media type
972    parameters in Accept. Future media types are discouraged from
973    registering any parameter named "q".
974  </t>
975</x:note>
976<t>
977   The example
978</t>
979<figure><artwork type="example">
980  Accept: audio/*; q=0.2, audio/basic
981</artwork></figure>
982<t>
983   &SHOULD; be interpreted as "I prefer audio/basic, but send me any audio
984   type if it is the best available after an 80% mark-down in quality".
985</t>
986<t>
987   If no Accept header field is present, then it is assumed that the
988   client accepts all media types. If an Accept header field is present in a
989   request, but the server cannot send a response which is acceptable, then
990   the server can either send a response in another format, or a 406 (Not
991   Acceptable) response.
992</t>
993<t>
994   A more elaborate example is
995</t>
996<figure><artwork type="example">
997  Accept: text/plain; q=0.5, text/html,
998          text/x-dvi; q=0.8, text/x-c
999</artwork></figure>
1000<t>
1001   Verbally, this would be interpreted as "text/html and text/x-c are
1002   the preferred media types, but if they do not exist, then send the
1003   text/x-dvi representation, and if that does not exist, send the text/plain
1004   representation".
1005</t>
1006<t>
1007   Media ranges can be overridden by more specific media ranges or
1008   specific media types. If more than one media range applies to a given
1009   type, the most specific reference has precedence. For example,
1010</t>
1011<figure><artwork type="example">
1012  Accept: text/*, text/plain, text/plain;format=flowed, */*
1013</artwork></figure>
1014<t>
1015   have the following precedence:
1016   <list style="numbers">
1017    <t>text/plain;format=flowed</t>
1018    <t>text/plain</t>
1019    <t>text/*</t>
1020    <t>*/*</t>
1021   </list>
1022</t>
1023<t>
1024   The media type quality factor associated with a given type is
1025   determined by finding the media range with the highest precedence
1026   which matches that type. For example,
1027</t>
1028<figure><artwork type="example">
1029  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
1030          text/html;level=2;q=0.4, */*;q=0.5
1031</artwork></figure>
1032<t>
1033   would cause the following values to be associated:
1034</t>
1035<texttable align="left">
1036  <ttcol>Media Type</ttcol><ttcol>Quality Value</ttcol>
1037  <c>text/html;level=1</c>    <c>1</c>
1038  <c>text/html</c>            <c>0.7</c>
1039  <c>text/plain</c>           <c>0.3</c>
1040  <c>image/jpeg</c>           <c>0.5</c>
1041  <c>text/html;level=2</c>    <c>0.4</c>
1042  <c>text/html;level=3</c>    <c>0.7</c>
1043</texttable>
1044<t>
1045      <x:h>Note:</x:h> A user agent might be provided with a default set of quality
1046      values for certain media ranges. However, unless the user agent is
1047      a closed system which cannot interact with other rendering agents,
1048      this default set ought to be configurable by the user.
1049</t>
1050</section>
1051
1052<section title="Accept-Charset" anchor="header.accept-charset">
1053  <iref primary="true" item="Accept-Charset header field" x:for-anchor=""/>
1054  <iref primary="true" item="Header Fields" subitem="Accept-Charset" x:for-anchor=""/>
1055  <x:anchor-alias value="Accept-Charset"/>
1056<t>
1057   The "Accept-Charset" header field can be used by user agents to
1058   indicate what character encodings are acceptable in a response
1059   payload. This field allows
1060   clients capable of understanding more comprehensive or special-purpose
1061   character encodings to signal that capability to a server which is capable of
1062   representing documents in those character encodings.
1063</t>
1064<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Charset"/>
1065  <x:ref>Accept-Charset</x:ref> = 1#( ( <x:ref>charset</x:ref> / "*" )
1066                         [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1067</artwork></figure>
1068<t>
1069   Character encoding values (a.k.a., charsets) are described in
1070   <xref target="character.sets"/>. Each charset &MAY; be given an
1071   associated quality value which represents the user's preference
1072   for that charset. The default value is q=1. An example is
1073</t>
1074<figure><artwork type="example">
1075  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
1076</artwork></figure>
1077<t>
1078   The special value "*", if present in the Accept-Charset field,
1079   matches every character encoding which is not mentioned elsewhere in the
1080   Accept-Charset field. If no "*" is present in an Accept-Charset field, then
1081   all character encodings not explicitly mentioned get a quality value of 0.
1082</t>
1083<t>
1084   If no Accept-Charset header field is present, the default is that any
1085   character encoding is acceptable. If an Accept-Charset header field is
1086   present in a request, but the server cannot send a response which is
1087   acceptable, then the server can either use another character encoding, or
1088   send a 406 (Not Acceptable) response.
1089</t>
1090</section>
1091
1092<section title="Accept-Encoding" anchor="header.accept-encoding">
1093  <iref primary="true" item="Accept-Encoding header field" x:for-anchor=""/>
1094  <iref primary="true" item="Header Fields" subitem="Accept-Encoding" x:for-anchor=""/>
1095  <x:anchor-alias value="Accept-Encoding"/>
1096  <x:anchor-alias value="codings"/>
1097<t>
1098   The "Accept-Encoding" header field can be used by user agents to
1099   indicate what response content-codings (<xref target="content.codings"/>)
1100   are acceptable in the response.
1101</t>
1102<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Encoding"/><iref primary="true" item="Grammar" subitem="codings"/>
1103  <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> ] )
1104  <x:ref>codings</x:ref>          = ( <x:ref>content-coding</x:ref> / "*" )
1105</artwork></figure>
1106<t>
1107   Each codings value &MAY; be given an associated quality value which
1108   represents the preference for that encoding. The default value is q=1.
1109</t>
1110<t>
1111   Examples of its use are:
1112</t>
1113<figure><artwork type="example">
1114  Accept-Encoding: compress, gzip
1115  Accept-Encoding:
1116  Accept-Encoding: *
1117  Accept-Encoding: compress;q=0.5, gzip;q=1.0
1118  Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
1119</artwork></figure>
1120<t>
1121   A server tests whether a content-coding is acceptable, according to
1122   an Accept-Encoding field, using these rules:
1123  <list style="numbers">
1124      <t>If the content-coding is one of the content-codings listed in
1125         the Accept-Encoding field, then it is acceptable, unless it is
1126         accompanied by a qvalue of 0. (As defined in &qvalue;, a
1127         qvalue of 0 means "not acceptable".)</t>
1128
1129      <t>The special "*" symbol in an Accept-Encoding field matches any
1130         available content-coding not explicitly listed in the header
1131         field.</t>
1132
1133      <t>If multiple content-codings are acceptable, then the acceptable
1134         content-coding with the highest non-zero qvalue is preferred.</t>
1135
1136      <t>The "identity" content-coding is always acceptable, unless
1137         specifically refused because the Accept-Encoding field includes
1138         "identity;q=0", or because the field includes "*;q=0" and does
1139         not explicitly include the "identity" content-coding. If the
1140         Accept-Encoding field-value is empty, then only the "identity"
1141         encoding is acceptable.</t>
1142  </list>
1143</t>
1144<t>
1145   If an Accept-Encoding field is present in a request, but the server cannot
1146   send a response which is acceptable, then the server &SHOULD; send a
1147   response without any encoding (i.e., the "identity" encoding).
1148</t>
1149<t>
1150   If no Accept-Encoding field is present in a request, the server &MAY;
1151   assume that the client will accept any content coding. In this case,
1152   if "identity" is one of the available content-codings, then the
1153   server &SHOULD; use the "identity" content-coding, unless it has
1154   additional information that a different content-coding is meaningful
1155   to the client.
1156</t>
1157<x:note>
1158  <t>
1159    <x:h>Note:</x:h> If the request does not include an Accept-Encoding field,
1160    and if the "identity" content-coding is unavailable, then
1161    content-codings commonly understood by HTTP/1.0 clients (i.e.,
1162    "gzip" and "compress") are preferred; some older clients
1163    improperly display messages sent with other content-codings.  The
1164    server might also make this decision based on information about
1165    the particular user-agent or client.
1166  </t>
1167</x:note>
1168<x:note>
1169  <t>
1170    <x:h>Note:</x:h> Most HTTP/1.0 applications do not recognize or obey qvalues
1171    associated with content-codings. This means that qvalues will not
1172    work and are not permitted with x-gzip or x-compress.
1173  </t>
1174</x:note>
1175</section>
1176
1177<section title="Accept-Language" anchor="header.accept-language">
1178  <iref primary="true" item="Accept-Language header field" x:for-anchor=""/>
1179  <iref primary="true" item="Header Fields" subitem="Accept-Language" x:for-anchor=""/>
1180  <x:anchor-alias value="Accept-Language"/>
1181  <x:anchor-alias value="language-range"/>
1182<t>
1183   The "Accept-Language" header field can be used by user agents to
1184   indicate the set of natural languages that are preferred in the response.
1185   Language tags are defined in <xref target="language.tags"/>.
1186</t>
1187<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Language"/><iref primary="true" item="Grammar" subitem="language-range"/>
1188  <x:ref>Accept-Language</x:ref> =
1189                    1#( <x:ref>language-range</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1190  <x:ref>language-range</x:ref>  =
1191            &lt;language-range, defined in <xref target="RFC4647" x:fmt="," x:sec="2.1"/>&gt;
1192</artwork></figure>
1193<t>
1194   Each language-range can be given an associated quality value which
1195   represents an estimate of the user's preference for the languages
1196   specified by that range. The quality value defaults to "q=1". For
1197   example,
1198</t>
1199<figure><artwork type="example">
1200  Accept-Language: da, en-gb;q=0.8, en;q=0.7
1201</artwork></figure>
1202<t>
1203   would mean: "I prefer Danish, but will accept British English and
1204   other types of English".
1205   (see also <xref target="RFC4647" x:sec="2.3" x:fmt="of"/>)
1206</t>
1207<t>
1208   For matching, <xref target="RFC4647" x:sec="3" x:fmt="of"/> defines
1209   several matching schemes. Implementations can offer the most appropriate
1210   matching scheme for their requirements.
1211</t>
1212<x:note>
1213  <t>
1214    <x:h>Note:</x:h> The "Basic Filtering" scheme (<xref target="RFC4647"
1215    x:fmt="," x:sec="3.3.1"/>) is identical to the matching scheme that was
1216    previously defined in <xref target="RFC2616" x:fmt="of" x:sec="14.4"/>.
1217  </t>
1218</x:note>
1219<t>
1220   It might be contrary to the privacy expectations of the user to send
1221   an Accept-Language header field with the complete linguistic preferences of
1222   the user in every request. For a discussion of this issue, see
1223   <xref target="privacy.issues.connected.to.accept.header.fields"/>.
1224</t>
1225<t>
1226   As intelligibility is highly dependent on the individual user, it is
1227   recommended that client applications make the choice of linguistic
1228   preference available to the user. If the choice is not made
1229   available, then the Accept-Language header field &MUST-NOT; be given in
1230   the request.
1231</t>
1232<x:note>
1233  <t>
1234    <x:h>Note:</x:h> When making the choice of linguistic preference available to
1235    the user, we remind implementors of  the fact that users are not
1236    familiar with the details of language matching as described above,
1237    and ought to be provided appropriate guidance. As an example, users
1238    might assume that on selecting "en-gb", they will be served any
1239    kind of English document if British English is not available. A
1240    user agent might suggest in such a case to add "en" to get the
1241    best matching behavior.
1242  </t>
1243</x:note>
1244</section>
1245
1246<section title="Content-Encoding" anchor="header.content-encoding">
1247  <iref primary="true" item="Content-Encoding header field" x:for-anchor=""/>
1248  <iref primary="true" item="Header Fields" subitem="Content-Encoding" x:for-anchor=""/>
1249  <x:anchor-alias value="Content-Encoding"/>
1250<t>
1251   The "Content-Encoding" header field indicates what content-codings
1252   have been applied to the representation, and thus what decoding mechanisms
1253   must be applied in order to obtain the media-type referenced by the
1254   Content-Type header field. Content-Encoding is primarily used to allow a
1255   representation to be compressed without losing the identity of its underlying
1256   media type.
1257</t>
1258<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Encoding"/>
1259  <x:ref>Content-Encoding</x:ref> = 1#<x:ref>content-coding</x:ref>
1260</artwork></figure>
1261<t>
1262   Content codings are defined in <xref target="content.codings"/>. An example of its use is
1263</t>
1264<figure><artwork type="example">
1265  Content-Encoding: gzip
1266</artwork></figure>
1267<t>
1268   The content-coding is a characteristic of the representation.
1269   Typically, the representation body is stored with this
1270   encoding and is only decoded before rendering or analogous usage.
1271   However, a transforming proxy &MAY; modify the content-coding if the
1272   new coding is known to be acceptable to the recipient, unless the
1273   "no-transform" cache-control directive is present in the message.
1274</t>
1275<t>
1276   If the content-coding of a representation is not "identity", then the
1277   representation metadata &MUST; include a Content-Encoding header
1278   field (<xref target="header.content-encoding"/>)
1279   that lists the non-identity content-coding(s) used.
1280</t>
1281<t>
1282   If the content-coding of a representation in a request message is not
1283   acceptable to the origin server, the server &SHOULD; respond with a
1284   status code of 415 (Unsupported Media Type).
1285</t>
1286<t>
1287   If multiple encodings have been applied to a representation, the content
1288   codings &MUST; be listed in the order in which they were applied.
1289   Additional information about the encoding parameters &MAY; be provided
1290   by other header fields not defined by this specification.
1291</t>
1292</section>
1293
1294<section title="Content-Language" anchor="header.content-language">
1295  <iref primary="true" item="Content-Language header field" x:for-anchor=""/>
1296  <iref primary="true" item="Header Fields" subitem="Content-Language" x:for-anchor=""/>
1297  <x:anchor-alias value="Content-Language"/>
1298<t>
1299   The "Content-Language" header field describes the natural
1300   language(s) of the intended audience for the representation. Note that this might
1301   not be equivalent to all the languages used within the representation.
1302</t>
1303<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Language"/>
1304  <x:ref>Content-Language</x:ref> = 1#<x:ref>language-tag</x:ref>
1305</artwork></figure>
1306<t>
1307   Language tags are defined in <xref target="language.tags"/>. The primary purpose of
1308   Content-Language is to allow a user to identify and differentiate
1309   representations according to the user's own preferred language. Thus, if the
1310   body content is intended only for a Danish-literate audience, the
1311   appropriate field is
1312</t>
1313<figure><artwork type="example">
1314  Content-Language: da
1315</artwork></figure>
1316<t>
1317   If no Content-Language is specified, the default is that the content
1318   is intended for all language audiences. This might mean that the
1319   sender does not consider it to be specific to any natural language,
1320   or that the sender does not know for which language it is intended.
1321</t>
1322<t>
1323   Multiple languages &MAY; be listed for content that is intended for
1324   multiple audiences. For example, a rendition of the "Treaty of
1325   Waitangi", presented simultaneously in the original Maori and English
1326   versions, would call for
1327</t>
1328<figure><artwork type="example">
1329  Content-Language: mi, en
1330</artwork></figure>
1331<t>
1332   However, just because multiple languages are present within a representation
1333   does not mean that it is intended for multiple linguistic audiences.
1334   An example would be a beginner's language primer, such as "A First
1335   Lesson in Latin", which is clearly intended to be used by an
1336   English-literate audience. In this case, the Content-Language would
1337   properly only include "en".
1338</t>
1339<t>
1340   Content-Language &MAY; be applied to any media type &mdash; it is not
1341   limited to textual documents.
1342</t>
1343</section>
1344
1345<section title="Content-Location" anchor="header.content-location">
1346  <iref primary="true" item="Content-Location header field" x:for-anchor=""/>
1347  <iref primary="true" item="Header Fields" subitem="Content-Location" x:for-anchor=""/>
1348  <x:anchor-alias value="Content-Location"/>
1349<t>
1350   The "Content-Location" header field supplies a URI that can be used
1351   as a specific identifier for the representation in this message.
1352   In other words, if one were to perform a GET on this URI at the time
1353   of this message's generation, then a 200 response would contain the
1354   same representation that is enclosed as payload in this message.
1355</t>
1356<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Location"/>
1357  <x:ref>Content-Location</x:ref> = <x:ref>absolute-URI</x:ref> / <x:ref>partial-URI</x:ref>
1358</artwork></figure>
1359<t>
1360   The Content-Location value is not a replacement for the effective
1361   Request URI (&effective-request-uri;).  It is representation metadata.
1362   It has the same syntax and semantics as the header field of the same name
1363   defined for MIME body parts in <xref target="RFC2557" x:fmt="of" x:sec="4"/>.
1364   However, its appearance in an HTTP message has some special implications
1365   for HTTP recipients.
1366</t>
1367<t>
1368   If Content-Location is included in a response message and its value
1369   is the same as the effective request URI, then the response payload
1370   &SHOULD; be considered the current representation of that resource.
1371   For a GET or HEAD request, this is the same as the default semantics
1372   when no Content-Location is provided by the server.  For a state-changing
1373   request like PUT or POST, it implies that the server's response contains
1374   the new representation of that resource, thereby distinguishing it from
1375   representations that might only report about the action (e.g., "It worked!").
1376   This allows authoring applications to update their local copies without
1377   the need for a subsequent GET request.
1378</t>
1379<t>
1380   If Content-Location is included in a response message and its value
1381   differs from the effective request URI, then the origin server is
1382   informing recipients that this representation has its own, presumably
1383   more specific, identifier.  For a GET or HEAD request, this is an
1384   indication that the effective request URI identifies a resource that
1385   is subject to content negotiation and the representation selected for
1386   this response can also be found at the identified URI.  For other
1387   methods, such a Content-Location indicates that this representation
1388   contains a report on the action's status and the same report is
1389   available (for future access with GET) at the given URI.  For
1390   example, a purchase transaction made via a POST request might
1391   include a receipt document as the payload of the 200 response;
1392   the Content-Location value provides an identifier for retrieving
1393   a copy of that same receipt in the future.
1394</t>
1395<t>
1396   If Content-Location is included in a request message, then it &MAY;
1397   be interpreted by the origin server as an indication of where the
1398   user agent originally obtained the content of the enclosed
1399   representation (prior to any subsequent modification of the content
1400   by that user agent).  In other words, the user agent is providing
1401   the same representation metadata that it received with the original
1402   representation.  However, such interpretation &MUST-NOT; be used to
1403   alter the semantics of the method requested by the client.  For
1404   example, if a client makes a PUT request on a negotiated resource
1405   and the origin server accepts that PUT (without redirection), then the
1406   new set of values for that resource is expected to be consistent with
1407   the one representation supplied in that PUT; the Content-Location
1408   cannot be used as a form of reverse content selection that
1409   identifies only one of the negotiated representations to be updated.
1410   If the user agent had wanted the latter semantics, it would have applied
1411   the PUT directly to the Content-Location URI.
1412</t>
1413<t>
1414   A Content-Location field received in a request message is transitory
1415   information that &SHOULD-NOT; be saved with other representation
1416   metadata for use in later responses.  The Content-Location's value
1417   might be saved for use in other contexts, such as within source links
1418   or other metadata.
1419</t>
1420<t>
1421   A cache cannot assume that a representation with a Content-Location
1422   different from the URI used to retrieve it can be used to respond to
1423   later requests on that Content-Location URI.
1424</t>
1425<t>
1426   If the Content-Location value is a partial URI, the partial URI is
1427   interpreted relative to the effective request URI.
1428</t>
1429</section>
1430
1431<section title="Content-Type" anchor="header.content-type">
1432  <iref primary="true" item="Content-Type header field" x:for-anchor=""/>
1433  <iref primary="true" item="Header Fields" subitem="Content-Type" x:for-anchor=""/>
1434  <x:anchor-alias value="Content-Type"/>
1435<t>
1436   The "Content-Type" header field indicates the media type of the
1437   representation. In the case of responses to the HEAD method, the media type is
1438   that which would have been sent had the request been a GET.
1439</t>
1440<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Type"/>
1441  <x:ref>Content-Type</x:ref> = <x:ref>media-type</x:ref>
1442</artwork></figure>
1443<t>
1444   Media types are defined in <xref target="media.types"/>. An example of the field is
1445</t>
1446<figure><artwork type="example">
1447  Content-Type: text/html; charset=ISO-8859-4
1448</artwork></figure>
1449<t>
1450   Further discussion of Content-Type is provided in <xref target="representation.data"/>.
1451</t>
1452</section>
1453
1454</section>
1455
1456<section title="IANA Considerations" anchor="IANA.considerations">
1457<section title="Header Field Registration" anchor="header.field.registration">
1458<t>
1459   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
1460   with the permanent registrations below (see <xref target="RFC3864"/>):
1461</t>
1462<?BEGININC p3-payload.iana-headers ?>
1463<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
1464<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
1465   <ttcol>Header Field Name</ttcol>
1466   <ttcol>Protocol</ttcol>
1467   <ttcol>Status</ttcol>
1468   <ttcol>Reference</ttcol>
1469
1470   <c>Accept</c>
1471   <c>http</c>
1472   <c>standard</c>
1473   <c>
1474      <xref target="header.accept"/>
1475   </c>
1476   <c>Accept-Charset</c>
1477   <c>http</c>
1478   <c>standard</c>
1479   <c>
1480      <xref target="header.accept-charset"/>
1481   </c>
1482   <c>Accept-Encoding</c>
1483   <c>http</c>
1484   <c>standard</c>
1485   <c>
1486      <xref target="header.accept-encoding"/>
1487   </c>
1488   <c>Accept-Language</c>
1489   <c>http</c>
1490   <c>standard</c>
1491   <c>
1492      <xref target="header.accept-language"/>
1493   </c>
1494   <c>Content-Encoding</c>
1495   <c>http</c>
1496   <c>standard</c>
1497   <c>
1498      <xref target="header.content-encoding"/>
1499   </c>
1500   <c>Content-Language</c>
1501   <c>http</c>
1502   <c>standard</c>
1503   <c>
1504      <xref target="header.content-language"/>
1505   </c>
1506   <c>Content-Location</c>
1507   <c>http</c>
1508   <c>standard</c>
1509   <c>
1510      <xref target="header.content-location"/>
1511   </c>
1512   <c>Content-Type</c>
1513   <c>http</c>
1514   <c>standard</c>
1515   <c>
1516      <xref target="header.content-type"/>
1517   </c>
1518   <c>MIME-Version</c>
1519   <c>http</c>
1520   <c>standard</c>
1521   <c>
1522      <xref target="mime-version"/>
1523   </c>
1524</texttable>
1525<!--(END)-->
1526<?ENDINC p3-payload.iana-headers ?>
1527<t>
1528   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
1529</t>
1530</section>
1531
1532<section title="Content Coding Registry" anchor="content.coding.registration">
1533<t>
1534   The registration procedure for HTTP Content Codings is now defined
1535   by <xref target="content.coding.registry"/> of this document.
1536</t>
1537<t>
1538   The HTTP Content Codings Registry located at <eref target="http://www.iana.org/assignments/http-parameters"/>
1539   shall be updated with the registration below:
1540</t>
1541<texttable align="left" suppress-title="true" anchor="iana.content.coding.registration.table">
1542   <ttcol>Name</ttcol>
1543   <ttcol>Description</ttcol>
1544   <ttcol>Reference</ttcol>
1545   <c>compress</c>
1546   <c>UNIX "compress" program method</c>
1547   <c>
1548      &compress-coding;
1549   </c>
1550   <c>deflate</c>
1551   <c>"deflate" compression mechanism (<xref target="RFC1951"/>) used inside
1552   the "zlib" data format (<xref target="RFC1950"/>)
1553   </c>
1554   <c>
1555      &deflate-coding;
1556   </c>
1557   <c>gzip</c>
1558   <c>Same as GNU zip <xref target="RFC1952"/></c>
1559   <c>
1560      &gzip-coding;
1561   </c>
1562   <c>identity</c>
1563   <c>No transformation</c>
1564   <c>
1565      <xref target="content.codings"/>
1566   </c>
1567</texttable>
1568</section>
1569
1570</section>
1571
1572<section title="Security Considerations" anchor="security.considerations">
1573<t>
1574   This section is meant to inform application developers, information
1575   providers, and users of the security limitations in HTTP/1.1 as
1576   described by this document. The discussion does not include
1577   definitive solutions to the problems revealed, though it does make
1578   some suggestions for reducing security risks.
1579</t>
1580
1581<section title="Privacy Issues Connected to Accept Header Fields" anchor="privacy.issues.connected.to.accept.header.fields">
1582<t>
1583   Accept headers fields can reveal information about the user to all
1584   servers which are accessed. The Accept-Language header field in particular
1585   can reveal information the user would consider to be of a private
1586   nature, because the understanding of particular languages is often
1587   strongly correlated to the membership of a particular ethnic group.
1588   User agents which offer the option to configure the contents of an
1589   Accept-Language header field to be sent in every request are strongly
1590   encouraged to let the configuration process include a message which
1591   makes the user aware of the loss of privacy involved.
1592</t>
1593<t>
1594   An approach that limits the loss of privacy would be for a user agent
1595   to omit the sending of Accept-Language header fields by default, and to ask
1596   the user whether or not to start sending Accept-Language header fields to a
1597   server if it detects, by looking for any Vary header fields
1598   generated by the server, that such sending could improve the quality
1599   of service.
1600</t>
1601<t>
1602   Elaborate user-customized accept header fields sent in every request,
1603   in particular if these include quality values, can be used by servers
1604   as relatively reliable and long-lived user identifiers. Such user
1605   identifiers would allow content providers to do click-trail tracking,
1606   and would allow collaborating content providers to match cross-server
1607   click-trails or form submissions of individual users. Note that for
1608   many users not behind a proxy, the network address of the host
1609   running the user agent will also serve as a long-lived user
1610   identifier. In environments where proxies are used to enhance
1611   privacy, user agents ought to be conservative in offering accept
1612   header configuration options to end users. As an extreme privacy
1613   measure, proxies could filter the accept header fields in relayed requests.
1614   General purpose user agents which provide a high degree of header
1615   configurability &SHOULD; warn users about the loss of privacy which can
1616   be involved.
1617</t>
1618</section>
1619
1620</section>
1621
1622<section title="Acknowledgments" anchor="acks">
1623<t>
1624  See &acks;.
1625</t>
1626</section>
1627</middle>
1628<back>
1629
1630<references title="Normative References">
1631
1632<reference anchor="Part1">
1633  <front>
1634    <title abbrev="HTTP/1.1">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1635    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1636      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1637      <address><email>fielding@gbiv.com</email></address>
1638    </author>
1639    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1640      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1641      <address><email>jg@freedesktop.org</email></address>
1642    </author>
1643    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1644      <organization abbrev="HP">Hewlett-Packard Company</organization>
1645      <address><email>JeffMogul@acm.org</email></address>
1646    </author>
1647    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1648      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1649      <address><email>henrikn@microsoft.com</email></address>
1650    </author>
1651    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1652      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1653      <address><email>LMM@acm.org</email></address>
1654    </author>
1655    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1656      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1657      <address><email>paulle@microsoft.com</email></address>
1658    </author>
1659    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1660      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1661      <address><email>timbl@w3.org</email></address>
1662    </author>
1663    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1664      <organization abbrev="W3C">World Wide Web Consortium</organization>
1665      <address><email>ylafon@w3.org</email></address>
1666    </author>
1667    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1668      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1669      <address><email>julian.reschke@greenbytes.de</email></address>
1670    </author>
1671    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1672  </front>
1673  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1674  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
1675</reference>
1676
1677<reference anchor="Part2">
1678  <front>
1679    <title abbrev="HTTP/1.1">HTTP/1.1, part 2: Message Semantics</title>
1680    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1681      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1682      <address><email>fielding@gbiv.com</email></address>
1683    </author>
1684    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1685      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1686      <address><email>jg@freedesktop.org</email></address>
1687    </author>
1688    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1689      <organization abbrev="HP">Hewlett-Packard Company</organization>
1690      <address><email>JeffMogul@acm.org</email></address>
1691    </author>
1692    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1693      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1694      <address><email>henrikn@microsoft.com</email></address>
1695    </author>
1696    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1697      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1698      <address><email>LMM@acm.org</email></address>
1699    </author>
1700    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1701      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1702      <address><email>paulle@microsoft.com</email></address>
1703    </author>
1704    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1705      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1706      <address><email>timbl@w3.org</email></address>
1707    </author>
1708    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1709      <organization abbrev="W3C">World Wide Web Consortium</organization>
1710      <address><email>ylafon@w3.org</email></address>
1711    </author>
1712    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1713      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1714      <address><email>julian.reschke@greenbytes.de</email></address>
1715    </author>
1716    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1717  </front>
1718  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1719  <x:source href="p2-semantics.xml" basename="p2-semantics"/>
1720</reference>
1721
1722<reference anchor="Part4">
1723  <front>
1724    <title abbrev="HTTP/1.1">HTTP/1.1, part 4: Conditional Requests</title>
1725    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1726      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1727      <address><email>fielding@gbiv.com</email></address>
1728    </author>
1729    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1730      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1731      <address><email>jg@freedesktop.org</email></address>
1732    </author>
1733    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1734      <organization abbrev="HP">Hewlett-Packard Company</organization>
1735      <address><email>JeffMogul@acm.org</email></address>
1736    </author>
1737    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1738      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1739      <address><email>henrikn@microsoft.com</email></address>
1740    </author>
1741    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1742      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1743      <address><email>LMM@acm.org</email></address>
1744    </author>
1745    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1746      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1747      <address><email>paulle@microsoft.com</email></address>
1748    </author>
1749    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1750      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1751      <address><email>timbl@w3.org</email></address>
1752    </author>
1753    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1754      <organization abbrev="W3C">World Wide Web Consortium</organization>
1755      <address><email>ylafon@w3.org</email></address>
1756    </author>
1757    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1758      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1759      <address><email>julian.reschke@greenbytes.de</email></address>
1760    </author>
1761    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1762  </front>
1763  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1764  <x:source href="p4-conditional.xml" basename="p4-conditional"/>
1765</reference>
1766
1767<reference anchor="Part5">
1768  <front>
1769    <title abbrev="HTTP/1.1">HTTP/1.1, part 5: Range Requests and Partial Responses</title>
1770    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1771      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1772      <address><email>fielding@gbiv.com</email></address>
1773    </author>
1774    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1775      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1776      <address><email>jg@freedesktop.org</email></address>
1777    </author>
1778    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1779      <organization abbrev="HP">Hewlett-Packard Company</organization>
1780      <address><email>JeffMogul@acm.org</email></address>
1781    </author>
1782    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1783      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1784      <address><email>henrikn@microsoft.com</email></address>
1785    </author>
1786    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1787      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1788      <address><email>LMM@acm.org</email></address>
1789    </author>
1790    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1791      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1792      <address><email>paulle@microsoft.com</email></address>
1793    </author>
1794    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1795      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1796      <address><email>timbl@w3.org</email></address>
1797    </author>
1798    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1799      <organization abbrev="W3C">World Wide Web Consortium</organization>
1800      <address><email>ylafon@w3.org</email></address>
1801    </author>
1802    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1803      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1804      <address><email>julian.reschke@greenbytes.de</email></address>
1805    </author>
1806    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1807  </front>
1808  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p5-range-&ID-VERSION;"/>
1809  <x:source href="p5-range.xml" basename="p5-range"/>
1810</reference>
1811
1812<reference anchor="Part6">
1813  <front>
1814    <title abbrev="HTTP/1.1">HTTP/1.1, part 6: Caching</title>
1815    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1816      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1817      <address><email>fielding@gbiv.com</email></address>
1818    </author>
1819    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1820      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1821      <address><email>jg@freedesktop.org</email></address>
1822    </author>
1823    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1824      <organization abbrev="HP">Hewlett-Packard Company</organization>
1825      <address><email>JeffMogul@acm.org</email></address>
1826    </author>
1827    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1828      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1829      <address><email>henrikn@microsoft.com</email></address>
1830    </author>
1831    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1832      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1833      <address><email>LMM@acm.org</email></address>
1834    </author>
1835    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1836      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1837      <address><email>paulle@microsoft.com</email></address>
1838    </author>
1839    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1840      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1841      <address><email>timbl@w3.org</email></address>
1842    </author>
1843    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1844      <organization abbrev="W3C">World Wide Web Consortium</organization>
1845      <address><email>ylafon@w3.org</email></address>
1846    </author>
1847    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1848      <address><email>mnot@mnot.net</email></address>
1849    </author>
1850    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1851      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1852      <address><email>julian.reschke@greenbytes.de</email></address>
1853    </author>
1854    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1855  </front>
1856  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1857  <x:source href="p6-cache.xml" basename="p6-cache"/>
1858</reference>
1859
1860<reference anchor="RFC1950">
1861  <front>
1862    <title>ZLIB Compressed Data Format Specification version 3.3</title>
1863    <author initials="L.P." surname="Deutsch" fullname="L. Peter Deutsch">
1864      <organization>Aladdin Enterprises</organization>
1865      <address><email>ghost@aladdin.com</email></address>
1866    </author>
1867    <author initials="J-L." surname="Gailly" fullname="Jean-Loup Gailly"/>
1868    <date month="May" year="1996"/>
1869  </front>
1870  <seriesInfo name="RFC" value="1950"/>
1871  <annotation>
1872    RFC 1950 is an Informational RFC, thus it might be less stable than
1873    this specification. On the other hand, this downward reference was
1874    present since the publication of RFC 2068 in 1997 (<xref target="RFC2068"/>),
1875    therefore it is unlikely to cause problems in practice. See also
1876    <xref target="BCP97"/>.
1877  </annotation>
1878</reference>
1879
1880<reference anchor="RFC1951">
1881  <front>
1882    <title>DEFLATE Compressed Data Format Specification version 1.3</title>
1883    <author initials="P." surname="Deutsch" fullname="L. Peter Deutsch">
1884      <organization>Aladdin Enterprises</organization>
1885      <address><email>ghost@aladdin.com</email></address>
1886    </author>
1887    <date month="May" year="1996"/>
1888  </front>
1889  <seriesInfo name="RFC" value="1951"/>
1890  <annotation>
1891    RFC 1951 is an Informational RFC, thus it might be less stable than
1892    this specification. On the other hand, this downward reference was
1893    present since the publication of RFC 2068 in 1997 (<xref target="RFC2068"/>),
1894    therefore it is unlikely to cause problems in practice. See also
1895    <xref target="BCP97"/>.
1896  </annotation>
1897</reference>
1898
1899<reference anchor="RFC1952">
1900  <front>
1901    <title>GZIP file format specification version 4.3</title>
1902    <author initials="P." surname="Deutsch" fullname="L. Peter Deutsch">
1903      <organization>Aladdin Enterprises</organization>
1904      <address><email>ghost@aladdin.com</email></address>
1905    </author>
1906    <author initials="J-L." surname="Gailly" fullname="Jean-Loup Gailly">
1907      <address><email>gzip@prep.ai.mit.edu</email></address>
1908    </author>
1909    <author initials="M." surname="Adler" fullname="Mark Adler">
1910      <address><email>madler@alumni.caltech.edu</email></address>
1911    </author>
1912    <author initials="L.P." surname="Deutsch" fullname="L. Peter Deutsch">
1913      <address><email>ghost@aladdin.com</email></address>
1914    </author>
1915    <author initials="G." surname="Randers-Pehrson" fullname="Glenn Randers-Pehrson">
1916      <address><email>randeg@alumni.rpi.edu</email></address>
1917    </author>
1918    <date month="May" year="1996"/>
1919  </front>
1920  <seriesInfo name="RFC" value="1952"/>
1921  <annotation>
1922    RFC 1952 is an Informational RFC, thus it might be less stable than
1923    this specification. On the other hand, this downward reference was
1924    present since the publication of RFC 2068 in 1997 (<xref target="RFC2068"/>),
1925    therefore it is unlikely to cause problems in practice. See also
1926    <xref target="BCP97"/>.
1927  </annotation>
1928</reference>
1929
1930<reference anchor="RFC2045">
1931  <front>
1932    <title abbrev="Internet Message Bodies">Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</title>
1933    <author initials="N." surname="Freed" fullname="Ned Freed">
1934      <organization>Innosoft International, Inc.</organization>
1935      <address><email>ned@innosoft.com</email></address>
1936    </author>
1937    <author initials="N.S." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1938      <organization>First Virtual Holdings</organization>
1939      <address><email>nsb@nsb.fv.com</email></address>
1940    </author>
1941    <date month="November" year="1996"/>
1942  </front>
1943  <seriesInfo name="RFC" value="2045"/>
1944</reference>
1945
1946<reference anchor="RFC2046">
1947  <front>
1948    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1949    <author initials="N." surname="Freed" fullname="Ned Freed">
1950      <organization>Innosoft International, Inc.</organization>
1951      <address><email>ned@innosoft.com</email></address>
1952    </author>
1953    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1954      <organization>First Virtual Holdings</organization>
1955      <address><email>nsb@nsb.fv.com</email></address>
1956    </author>
1957    <date month="November" year="1996"/>
1958  </front>
1959  <seriesInfo name="RFC" value="2046"/>
1960</reference>
1961
1962<reference anchor="RFC2119">
1963  <front>
1964    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1965    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1966      <organization>Harvard University</organization>
1967      <address><email>sob@harvard.edu</email></address>
1968    </author>
1969    <date month="March" year="1997"/>
1970  </front>
1971  <seriesInfo name="BCP" value="14"/>
1972  <seriesInfo name="RFC" value="2119"/>
1973</reference>
1974
1975<reference anchor='RFC4647'>
1976  <front>
1977    <title>Matching of Language Tags</title>
1978    <author initials='A.' surname='Phillips' fullname='Addison Phillips' role="editor">
1979      <organization>Yahoo! Inc.</organization>
1980      <address><email>addison@inter-locale.com</email></address>
1981    </author>
1982    <author initials='M.' surname='Davis' fullname='Mark Davis' role="editor">
1983      <organization>Google</organization>
1984      <address><email>mark.davis@macchiato.com</email></address>
1985    </author>
1986    <date year='2006' month='September' />
1987  </front>
1988  <seriesInfo name='BCP' value='47' />
1989  <seriesInfo name='RFC' value='4647' />
1990</reference>
1991
1992<reference anchor="RFC5234">
1993  <front>
1994    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1995    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1996      <organization>Brandenburg InternetWorking</organization>
1997      <address>
1998        <email>dcrocker@bbiw.net</email>
1999      </address> 
2000    </author>
2001    <author initials="P." surname="Overell" fullname="Paul Overell">
2002      <organization>THUS plc.</organization>
2003      <address>
2004        <email>paul.overell@thus.net</email>
2005      </address>
2006    </author>
2007    <date month="January" year="2008"/>
2008  </front>
2009  <seriesInfo name="STD" value="68"/>
2010  <seriesInfo name="RFC" value="5234"/>
2011</reference>
2012
2013<reference anchor='RFC5646'>
2014  <front>
2015    <title>Tags for Identifying Languages</title>
2016    <author initials='A.' surname='Phillips' fullname='Addison Phillips' role='editor'>
2017      <organization>Lab126</organization>
2018      <address><email>addison@inter-locale.com</email></address>
2019    </author>
2020    <author initials='M.' surname='Davis' fullname='Mark Davis' role='editor'>
2021      <organization>Google</organization>
2022      <address><email>mark.davis@google.com</email></address>
2023    </author>
2024    <date month='September' year='2009' />
2025  </front>
2026  <seriesInfo name='BCP' value='47' />
2027  <seriesInfo name='RFC' value='5646' />
2028</reference>
2029
2030</references>
2031
2032<references title="Informative References">
2033
2034<reference anchor="RFC1945">
2035  <front>
2036    <title abbrev="HTTP/1.0">Hypertext Transfer Protocol -- HTTP/1.0</title>
2037    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
2038      <organization>MIT, Laboratory for Computer Science</organization>
2039      <address><email>timbl@w3.org</email></address>
2040    </author>
2041    <author initials="R.T." surname="Fielding" fullname="Roy T. Fielding">
2042      <organization>University of California, Irvine, Department of Information and Computer Science</organization>
2043      <address><email>fielding@ics.uci.edu</email></address>
2044    </author>
2045    <author initials="H.F." surname="Nielsen" fullname="Henrik Frystyk Nielsen">
2046      <organization>W3 Consortium, MIT Laboratory for Computer Science</organization>
2047      <address><email>frystyk@w3.org</email></address>
2048    </author>
2049    <date month="May" year="1996"/>
2050  </front>
2051  <seriesInfo name="RFC" value="1945"/>
2052</reference>
2053
2054<reference anchor="RFC2049">
2055  <front>
2056    <title abbrev="MIME Conformance">Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples</title>
2057    <author initials="N." surname="Freed" fullname="Ned Freed">
2058      <organization>Innosoft International, Inc.</organization>
2059      <address><email>ned@innosoft.com</email></address>
2060    </author>
2061    <author initials="N.S." surname="Borenstein" fullname="Nathaniel S. Borenstein">
2062      <organization>First Virtual Holdings</organization>
2063      <address><email>nsb@nsb.fv.com</email></address>
2064    </author>
2065    <date month="November" year="1996"/>
2066  </front>
2067  <seriesInfo name="RFC" value="2049"/>
2068</reference>
2069
2070<reference anchor="RFC2068">
2071  <front>
2072    <title abbrev="HTTP/1.1">Hypertext Transfer Protocol -- HTTP/1.1</title>
2073    <author initials="R." surname="Fielding" fullname="Roy T. Fielding">
2074      <organization>University of California, Irvine, Department of Information and Computer Science</organization>
2075      <address><email>fielding@ics.uci.edu</email></address>
2076    </author>
2077    <author initials="J." surname="Gettys" fullname="Jim Gettys">
2078      <organization>MIT Laboratory for Computer Science</organization>
2079      <address><email>jg@w3.org</email></address>
2080    </author>
2081    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
2082      <organization>Digital Equipment Corporation, Western Research Laboratory</organization>
2083      <address><email>mogul@wrl.dec.com</email></address>
2084    </author>
2085    <author initials="H." surname="Nielsen" fullname="Henrik Frystyk Nielsen">
2086      <organization>MIT Laboratory for Computer Science</organization>
2087      <address><email>frystyk@w3.org</email></address>
2088    </author>
2089    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
2090      <organization>MIT Laboratory for Computer Science</organization>
2091      <address><email>timbl@w3.org</email></address>
2092    </author>
2093    <date month="January" year="1997"/>
2094  </front>
2095  <seriesInfo name="RFC" value="2068"/>
2096</reference>
2097
2098<reference anchor="RFC2076">
2099  <front>
2100    <title abbrev="Internet Message Headers">Common Internet Message Headers</title>
2101    <author initials="J." surname="Palme" fullname="Jacob Palme">
2102      <organization>Stockholm University/KTH</organization>
2103      <address><email>jpalme@dsv.su.se</email></address>
2104    </author>
2105    <date month="February" year="1997"/>
2106  </front>
2107  <seriesInfo name="RFC" value="2076"/>
2108</reference>
2109
2110<reference anchor="RFC2277">
2111  <front>
2112    <title abbrev="Charset Policy">IETF Policy on Character Sets and Languages</title>
2113    <author initials="H.T." surname="Alvestrand" fullname="Harald Tveit Alvestrand">
2114      <organization>UNINETT</organization>
2115      <address><email>Harald.T.Alvestrand@uninett.no</email></address>
2116    </author>
2117    <date month="January" year="1998"/>
2118  </front>
2119  <seriesInfo name="BCP" value="18"/>
2120  <seriesInfo name="RFC" value="2277"/>
2121</reference>
2122
2123<reference anchor='RFC2295'>
2124  <front>
2125    <title abbrev='HTTP Content Negotiation'>Transparent Content Negotiation in HTTP</title>
2126    <author initials='K.' surname='Holtman' fullname='Koen Holtman'>
2127      <organization>Technische Universiteit Eindhoven</organization>
2128      <address>
2129        <email>koen@win.tue.nl</email>
2130      </address>
2131    </author>
2132    <author initials='A.H.' surname='Mutz' fullname='Andrew H. Mutz'>
2133      <organization>Hewlett-Packard Company</organization>
2134      <address>
2135        <email>mutz@hpl.hp.com</email>
2136      </address>
2137    </author>
2138    <date year='1998' month='March'/>
2139  </front>
2140  <seriesInfo name='RFC' value='2295'/>
2141</reference>
2142
2143<reference anchor="RFC2388">
2144  <front>
2145    <title abbrev="multipart/form-data">Returning Values from Forms:  multipart/form-data</title>
2146    <author initials="L." surname="Masinter" fullname="Larry Masinter">
2147      <organization>Xerox Palo Alto Research Center</organization>
2148      <address><email>masinter@parc.xerox.com</email></address>
2149    </author>
2150    <date year="1998" month="August"/>
2151  </front>
2152  <seriesInfo name="RFC" value="2388"/>
2153</reference>
2154
2155<reference anchor="RFC2557">
2156  <front>
2157    <title abbrev="MIME Encapsulation of Aggregate Documents">MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)</title>
2158    <author initials="F." surname="Palme" fullname="Jacob Palme">
2159      <organization>Stockholm University and KTH</organization>
2160      <address><email>jpalme@dsv.su.se</email></address>
2161    </author>
2162    <author initials="A." surname="Hopmann" fullname="Alex Hopmann">
2163      <organization>Microsoft Corporation</organization>
2164      <address><email>alexhop@microsoft.com</email></address>
2165    </author>
2166    <author initials="N." surname="Shelness" fullname="Nick Shelness">
2167      <organization>Lotus Development Corporation</organization>
2168      <address><email>Shelness@lotus.com</email></address>
2169    </author>
2170    <author initials="E." surname="Stefferud" fullname="Einar Stefferud">
2171      <address><email>stef@nma.com</email></address>
2172    </author>
2173    <date year="1999" month="March"/>
2174  </front>
2175  <seriesInfo name="RFC" value="2557"/>
2176</reference>
2177
2178<reference anchor="RFC2616">
2179  <front>
2180    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
2181    <author initials="R." surname="Fielding" fullname="R. Fielding">
2182      <organization>University of California, Irvine</organization>
2183      <address><email>fielding@ics.uci.edu</email></address>
2184    </author>
2185    <author initials="J." surname="Gettys" fullname="J. Gettys">
2186      <organization>W3C</organization>
2187      <address><email>jg@w3.org</email></address>
2188    </author>
2189    <author initials="J." surname="Mogul" fullname="J. Mogul">
2190      <organization>Compaq Computer Corporation</organization>
2191      <address><email>mogul@wrl.dec.com</email></address>
2192    </author>
2193    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
2194      <organization>MIT Laboratory for Computer Science</organization>
2195      <address><email>frystyk@w3.org</email></address>
2196    </author>
2197    <author initials="L." surname="Masinter" fullname="L. Masinter">
2198      <organization>Xerox Corporation</organization>
2199      <address><email>masinter@parc.xerox.com</email></address>
2200    </author>
2201    <author initials="P." surname="Leach" fullname="P. Leach">
2202      <organization>Microsoft Corporation</organization>
2203      <address><email>paulle@microsoft.com</email></address>
2204    </author>
2205    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
2206      <organization>W3C</organization>
2207      <address><email>timbl@w3.org</email></address>
2208    </author>
2209    <date month="June" year="1999"/>
2210  </front>
2211  <seriesInfo name="RFC" value="2616"/>
2212</reference>
2213
2214<reference anchor="RFC3629">
2215  <front>
2216    <title>UTF-8, a transformation format of ISO 10646</title>
2217    <author initials="F." surname="Yergeau" fullname="F. Yergeau">
2218      <organization>Alis Technologies</organization>
2219      <address><email>fyergeau@alis.com</email></address>
2220    </author>
2221    <date month="November" year="2003"/>
2222  </front>
2223  <seriesInfo name="STD" value="63"/>
2224  <seriesInfo name="RFC" value="3629"/>
2225</reference>
2226
2227<reference anchor='RFC3864'>
2228  <front>
2229    <title>Registration Procedures for Message Header Fields</title>
2230    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
2231      <organization>Nine by Nine</organization>
2232      <address><email>GK-IETF@ninebynine.org</email></address>
2233    </author>
2234    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
2235      <organization>BEA Systems</organization>
2236      <address><email>mnot@pobox.com</email></address>
2237    </author>
2238    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
2239      <organization>HP Labs</organization>
2240      <address><email>JeffMogul@acm.org</email></address>
2241    </author>
2242    <date year='2004' month='September' />
2243  </front>
2244  <seriesInfo name='BCP' value='90' />
2245  <seriesInfo name='RFC' value='3864' />
2246</reference>
2247
2248<reference anchor="RFC4288">
2249  <front>
2250    <title>Media Type Specifications and Registration Procedures</title>
2251    <author initials="N." surname="Freed" fullname="N. Freed">
2252      <organization>Sun Microsystems</organization>
2253      <address>
2254        <email>ned.freed@mrochek.com</email>
2255      </address>
2256    </author>
2257    <author initials="J." surname="Klensin" fullname="J. Klensin">
2258      <address>
2259        <email>klensin+ietf@jck.com</email>
2260      </address>
2261    </author>
2262    <date year="2005" month="December"/>
2263  </front>
2264  <seriesInfo name="BCP" value="13"/>
2265  <seriesInfo name="RFC" value="4288"/>
2266</reference>
2267
2268<reference anchor='RFC5226'>
2269  <front>
2270    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
2271    <author initials='T.' surname='Narten' fullname='T. Narten'>
2272      <organization>IBM</organization>
2273      <address><email>narten@us.ibm.com</email></address>
2274    </author>
2275    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
2276      <organization>Google</organization>
2277      <address><email>Harald@Alvestrand.no</email></address>
2278    </author>
2279    <date year='2008' month='May' />
2280  </front>
2281  <seriesInfo name='BCP' value='26' />
2282  <seriesInfo name='RFC' value='5226' />
2283</reference>
2284
2285<reference anchor="RFC5322">
2286  <front>
2287    <title>Internet Message Format</title>
2288    <author initials="P." surname="Resnick" fullname="P. Resnick">
2289      <organization>Qualcomm Incorporated</organization>
2290    </author>
2291    <date year="2008" month="October"/>
2292  </front> 
2293  <seriesInfo name="RFC" value="5322"/>
2294</reference>
2295
2296<reference anchor="RFC6151">
2297  <front>
2298    <title>Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms</title>
2299    <author initials="S." surname="Turner" fullname="S. Turner"/>
2300    <author initials="L." surname="Chen" fullname="L. Chen"/>
2301    <date year="2011" month="March" />
2302  </front>
2303  <seriesInfo name="RFC" value="6151" />
2304</reference>
2305
2306<reference anchor='BCP97'>
2307  <front>
2308    <title>Handling Normative References to Standards-Track Documents</title>
2309    <author initials='J.' surname='Klensin' fullname='J. Klensin'>
2310      <address>
2311        <email>klensin+ietf@jck.com</email>
2312      </address>
2313    </author>
2314    <author initials='S.' surname='Hartman' fullname='S. Hartman'>
2315      <organization>MIT</organization>
2316      <address>
2317        <email>hartmans-ietf@mit.edu</email>
2318      </address>
2319    </author>
2320    <date year='2007' month='June' />
2321  </front>
2322  <seriesInfo name='BCP' value='97' />
2323  <seriesInfo name='RFC' value='4897' />
2324</reference>
2325
2326<reference anchor="RFC6266">
2327  <front>
2328    <title abbrev="Content-Disposition in HTTP">Use of the Content-Disposition Header Field
2329    in the Hypertext Transfer Protocol (HTTP)</title>
2330    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke">
2331      <organization abbrev="greenbytes">greenbytes GmbH</organization>
2332      <address>
2333        <email>julian.reschke@greenbytes.de</email>
2334      </address>
2335    </author>
2336    <date month="June" year="2011"/>
2337  </front>
2338  <seriesInfo name='RFC' value='6266' />
2339</reference>
2340
2341</references>
2342
2343<section title="Differences between HTTP and MIME" anchor="differences.between.http.and.mime">
2344<t>
2345   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
2346   allow a message-body to be transmitted in an open variety of
2347   representations and with extensible mechanisms. However, RFC 2045
2348   discusses mail, and HTTP has a few features that are different from
2349   those described in MIME. These differences were carefully chosen
2350   to optimize performance over binary connections, to allow greater
2351   freedom in the use of new media types, to make date comparisons
2352   easier, and to acknowledge the practice of some early HTTP servers
2353   and clients.
2354</t>
2355<t>
2356   This appendix describes specific areas where HTTP differs from MIME.
2357   Proxies and gateways to strict MIME environments &SHOULD; be
2358   aware of these differences and provide the appropriate conversions
2359   where necessary. Proxies and gateways from MIME environments to HTTP
2360   also need to be aware of the differences because some conversions
2361   might be required.
2362</t>
2363
2364<section title="MIME-Version" anchor="mime-version">
2365  <iref primary="true" item="MIME-Version header field" x:for-anchor=""/>
2366  <iref primary="true" item="Header Fields" subitem="MIME-Version" x:for-anchor=""/>
2367  <x:anchor-alias value="MIME-Version"/>
2368<t>
2369   HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages &MAY;
2370   include a single MIME-Version header field to indicate what
2371   version of the MIME protocol was used to construct the message. Use
2372   of the MIME-Version header field indicates that the message is in
2373   full compliance with the MIME protocol (as defined in <xref target="RFC2045"/>).
2374   Proxies/gateways are responsible for ensuring full compliance (where
2375   possible) when exporting HTTP messages to strict MIME environments.
2376</t>
2377<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="MIME-Version"/>
2378  <x:ref>MIME-Version</x:ref> = 1*<x:ref>DIGIT</x:ref> "." 1*<x:ref>DIGIT</x:ref>
2379</artwork></figure>
2380<t>
2381   MIME version "1.0" is the default for use in HTTP/1.1. However,
2382   HTTP/1.1 message parsing and semantics are defined by this document
2383   and not the MIME specification.
2384</t>
2385</section>
2386
2387<section title="Conversion to Canonical Form" anchor="conversion.to.canonical.form">
2388<t>
2389   MIME requires that an Internet mail body-part be converted to
2390   canonical form prior to being transferred, as described in <xref target="RFC2049" x:fmt="of" x:sec="4"/>.
2391   <xref target="canonicalization.and.text.defaults"/> of this document describes the forms
2392   allowed for subtypes of the "text" media type when transmitted over
2393   HTTP. <xref target="RFC2046"/> requires that content with a type of "text" represent
2394   line breaks as CRLF and forbids the use of CR or LF outside of line
2395   break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a
2396   line break within text content when a message is transmitted over
2397   HTTP.
2398</t>
2399<t>
2400   Where it is possible, a proxy or gateway from HTTP to a strict MIME
2401   environment &SHOULD; translate all line breaks within the text media
2402   types described in <xref target="canonicalization.and.text.defaults"/>
2403   of this document to the RFC 2049
2404   canonical form of CRLF. Note, however, that this might be complicated
2405   by the presence of a Content-Encoding and by the fact that HTTP
2406   allows the use of some character encodings which do not use octets 13 and
2407   10 to represent CR and LF, respectively, as is the case for some multi-byte
2408   character encodings.
2409</t>
2410<t>
2411   Conversion will break any cryptographic
2412   checksums applied to the original content unless the original content
2413   is already in canonical form. Therefore, the canonical form is
2414   recommended for any content that uses such checksums in HTTP.
2415</t>
2416</section>
2417
2418
2419<section title="Conversion of Date Formats" anchor="conversion.of.date.formats">
2420<t>
2421   HTTP/1.1 uses a restricted set of date formats (&full-date;) to
2422   simplify the process of date comparison. Proxies and gateways from
2423   other protocols &SHOULD; ensure that any Date header field present in a
2424   message conforms to one of the HTTP/1.1 formats and rewrite the date
2425   if necessary.
2426</t>
2427</section>
2428
2429<section title="Introduction of Content-Encoding" anchor="introduction.of.content-encoding">
2430<t>
2431   MIME does not include any concept equivalent to HTTP/1.1's
2432   Content-Encoding header field. Since this acts as a modifier on the
2433   media type, proxies and gateways from HTTP to MIME-compliant
2434   protocols &MUST; either change the value of the Content-Type header
2435   field or decode the representation before forwarding the message. (Some
2436   experimental applications of Content-Type for Internet mail have used
2437   a media-type parameter of ";conversions=&lt;content-coding&gt;" to perform
2438   a function equivalent to Content-Encoding. However, this parameter is
2439   not part of the MIME standards).
2440</t>
2441</section>
2442
2443<section title="No Content-Transfer-Encoding" anchor="no.content-transfer-encoding">
2444<t>
2445   HTTP does not use the Content-Transfer-Encoding field of MIME.
2446   Proxies and gateways from MIME-compliant protocols to HTTP &MUST;
2447   remove any Content-Transfer-Encoding
2448   prior to delivering the response message to an HTTP client.
2449</t>
2450<t>
2451   Proxies and gateways from HTTP to MIME-compliant protocols are
2452   responsible for ensuring that the message is in the correct format
2453   and encoding for safe transport on that protocol, where "safe
2454   transport" is defined by the limitations of the protocol being used.
2455   Such a proxy or gateway &SHOULD; label the data with an appropriate
2456   Content-Transfer-Encoding if doing so will improve the likelihood of
2457   safe transport over the destination protocol.
2458</t>
2459</section>
2460
2461<section title="Introduction of Transfer-Encoding" anchor="introduction.of.transfer-encoding">
2462<t>
2463   HTTP/1.1 introduces the Transfer-Encoding header field (&header-transfer-encoding;).
2464   Proxies/gateways &MUST; remove any transfer-coding prior to
2465   forwarding a message via a MIME-compliant protocol.
2466</t>
2467</section>
2468
2469<section title="MHTML and Line Length Limitations" anchor="mhtml.line.length">
2470<t>
2471   HTTP implementations which share code with MHTML <xref target="RFC2557"/> implementations
2472   need to be aware of MIME line length limitations. Since HTTP does not
2473   have this limitation, HTTP does not fold long lines. MHTML messages
2474   being transported by HTTP follow all conventions of MHTML, including
2475   line length limitations and folding, canonicalization, etc., since
2476   HTTP transports all message-bodies as payload (see <xref target="multipart.types"/>) and
2477   does not interpret the content or any MIME header lines that might be
2478   contained therein.
2479</t>
2480</section>
2481</section>
2482
2483<section title="Additional Features" anchor="additional.features">
2484<t>
2485   <xref target="RFC1945"/> and <xref target="RFC2068"/> document protocol elements used by some
2486   existing HTTP implementations, but not consistently and correctly
2487   across most HTTP/1.1 applications. Implementors are advised to be
2488   aware of these features, but cannot rely upon their presence in, or
2489   interoperability with, other HTTP/1.1 applications. Some of these
2490   describe proposed experimental features, and some describe features
2491   that experimental deployment found lacking that are now addressed in
2492   the base HTTP/1.1 specification.
2493</t>
2494<t>
2495   A number of other header fields, such as Content-Disposition and Title,
2496   from SMTP and MIME are also often implemented (see <xref target="RFC6266"/>
2497   and <xref target="RFC2076"/>).
2498</t>
2499</section>
2500
2501<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
2502<t>
2503  Clarify contexts that charset is used in.
2504  (<xref target="character.sets"/>)
2505</t>
2506<t>
2507  Remove the default character encoding for text media types; the default
2508  now is whatever the media type definition says.
2509  (<xref target="canonicalization.and.text.defaults"/>)
2510</t>
2511<t>
2512  Change ABNF productions for header fields to only define the field value.
2513  (<xref target="header.fields"/>)
2514</t>
2515<t>
2516  Remove definition of Content-MD5 header field because it was inconsistently
2517  implemented with respect to partial responses, and also because of known
2518  deficiencies in the hash algorithm itself (see <xref target="RFC6151"/> for details).
2519  (<xref target="header.fields"/>)
2520</t>
2521<t>
2522  Remove ISO-8859-1 special-casing in Accept-Charset.
2523  (<xref target="header.accept-charset"/>)
2524</t>
2525<t>
2526  Remove base URI setting semantics for Content-Location due to poor
2527  implementation support, which was caused by too many broken servers emitting
2528  bogus Content-Location header fields, and also the potentially undesirable effect
2529  of potentially breaking relative links in content-negotiated resources.
2530  (<xref target="header.content-location"/>)
2531</t>
2532<t>
2533  Remove discussion of Content-Disposition header field, it is now defined
2534  by <xref target="RFC6266"/>.
2535  (<xref target="additional.features"/>)
2536</t>
2537<t>
2538  Remove reference to non-existant identity transfer-coding value tokens.
2539  (<xref target="no.content-transfer-encoding"/>)
2540</t>
2541</section>
2542
2543<?BEGININC p3-payload.abnf-appendix ?>
2544<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
2545<figure>
2546<artwork type="abnf" name="p3-payload.parsed-abnf">
2547<x:ref>Accept</x:ref> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [
2548 OWS media-range [ accept-params ] ] ) ]
2549<x:ref>Accept-Charset</x:ref> = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q="
2550 qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q="
2551 qvalue ] ] )
2552<x:ref>Accept-Encoding</x:ref> = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) )
2553 *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ]
2554<x:ref>Accept-Language</x:ref> = *( "," OWS ) language-range [ OWS ";" OWS "q="
2555 qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ]
2556 ] )
2557
2558<x:ref>Content-Encoding</x:ref> = *( "," OWS ) content-coding *( OWS "," [ OWS
2559 content-coding ] )
2560<x:ref>Content-Language</x:ref> = *( "," OWS ) language-tag *( OWS "," [ OWS
2561 language-tag ] )
2562<x:ref>Content-Location</x:ref> = absolute-URI / partial-URI
2563<x:ref>Content-Type</x:ref> = media-type
2564
2565<x:ref>MIME-Version</x:ref> = 1*DIGIT "." 1*DIGIT
2566
2567<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 1.2.2&gt;
2568
2569<x:ref>absolute-URI</x:ref> = &lt;absolute-URI, defined in [Part1], Section 2.7&gt;
2570<x:ref>accept-ext</x:ref> = OWS ";" OWS token [ "=" word ]
2571<x:ref>accept-params</x:ref> = OWS ";" OWS "q=" qvalue *accept-ext
2572<x:ref>attribute</x:ref> = token
2573
2574<x:ref>charset</x:ref> = token
2575<x:ref>codings</x:ref> = ( content-coding / "*" )
2576<x:ref>content-coding</x:ref> = token
2577
2578<x:ref>language-range</x:ref> = &lt;language-range, defined in [RFC4647], Section 2.1&gt;
2579<x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in [RFC5646], Section 2.1&gt;
2580
2581<x:ref>media-range</x:ref> = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS
2582 ";" OWS parameter )
2583<x:ref>media-type</x:ref> = type "/" subtype *( OWS ";" OWS parameter )
2584
2585<x:ref>parameter</x:ref> = attribute "=" value
2586<x:ref>partial-URI</x:ref> = &lt;partial-URI, defined in [Part1], Section 2.7&gt;
2587
2588<x:ref>qvalue</x:ref> = &lt;qvalue, defined in [Part1], Section 6.4&gt;
2589
2590<x:ref>subtype</x:ref> = token
2591
2592<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 1.2.2&gt;
2593<x:ref>type</x:ref> = token
2594
2595<x:ref>value</x:ref> = word
2596
2597<x:ref>word</x:ref> = &lt;word, defined in [Part1], Section 1.2.2&gt;
2598</artwork>
2599</figure>
2600<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
2601; Accept defined but not used
2602; Accept-Charset defined but not used
2603; Accept-Encoding defined but not used
2604; Accept-Language defined but not used
2605; Content-Encoding defined but not used
2606; Content-Language defined but not used
2607; Content-Location defined but not used
2608; Content-Type defined but not used
2609; MIME-Version defined but not used
2610</artwork></figure></section>
2611<?ENDINC p3-payload.abnf-appendix ?>
2612
2613<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
2614
2615<section title="Since RFC 2616">
2616<t>
2617  Extracted relevant partitions from <xref target="RFC2616"/>.
2618</t>
2619</section>
2620
2621<section title="Since draft-ietf-httpbis-p3-payload-00">
2622<t>
2623  Closed issues:
2624  <list style="symbols"> 
2625    <t>
2626      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/8"/>:
2627      "Media Type Registrations"
2628      (<eref target="http://purl.org/NET/http-errata#media-reg"/>)
2629    </t>
2630    <t>
2631      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/14"/>:
2632      "Clarification regarding quoting of charset values"
2633      (<eref target="http://purl.org/NET/http-errata#charactersets"/>)
2634    </t>
2635    <t>
2636      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/16"/>:
2637      "Remove 'identity' token references"
2638      (<eref target="http://purl.org/NET/http-errata#identity"/>)
2639    </t>
2640    <t>
2641      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/25"/>:
2642      "Accept-Encoding BNF"
2643    </t>
2644    <t>
2645      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
2646      "Normative and Informative references"
2647    </t>
2648    <t>
2649      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/46"/>:
2650      "RFC1700 references"
2651    </t>
2652    <t>
2653      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
2654      "Updating to RFC4288"
2655    </t>
2656    <t>
2657      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/65"/>:
2658      "Informative references"
2659    </t>
2660    <t>
2661      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/66"/>:
2662      "ISO-8859-1 Reference"
2663    </t>
2664    <t>
2665      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>:
2666      "Encoding References Normative"
2667    </t>
2668    <t>
2669      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
2670      "Normative up-to-date references"
2671    </t>
2672  </list>
2673</t>
2674</section>
2675
2676<section title="Since draft-ietf-httpbis-p3-payload-01">
2677<t>
2678  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2679  <list style="symbols"> 
2680    <t>
2681      Add explicit references to BNF syntax and rules imported from other parts of the specification.
2682    </t>
2683  </list>
2684</t>
2685</section>
2686
2687<section title="Since draft-ietf-httpbis-p3-payload-02" anchor="changes.since.02">
2688<t>
2689  Closed issues:
2690  <list style="symbols"> 
2691    <t>
2692      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>:
2693      "Quoting Charsets"
2694    </t>
2695    <t>
2696      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/105"/>:
2697      "Classification for Allow header"
2698    </t>
2699    <t>
2700      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/115"/>:
2701      "missing default for qvalue in description of Accept-Encoding"
2702    </t>
2703  </list>
2704</t>
2705<t>
2706  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
2707  <list style="symbols"> 
2708    <t>
2709      Reference RFC 3984, and update header field registrations for headers defined
2710      in this document.
2711    </t>
2712  </list>
2713</t>
2714</section>
2715
2716<section title="Since draft-ietf-httpbis-p3-payload-03" anchor="changes.since.03">
2717<t>
2718  Closed issues:
2719  <list style="symbols"> 
2720    <t>
2721      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>:
2722      "Quoting Charsets"
2723    </t>
2724    <t>
2725      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/113"/>:
2726      "language tag matching (Accept-Language) vs RFC4647"
2727    </t>
2728    <t>
2729      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/121"/>:
2730      "RFC 1806 has been replaced by RFC2183"
2731    </t>
2732  </list>
2733</t>
2734<t>
2735  Other changes:
2736  <list style="symbols"> 
2737    <t>
2738      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>:
2739      "Encoding References Normative" &mdash; rephrase the annotation and reference
2740      <xref target="BCP97"/>.
2741    </t>
2742  </list>
2743</t>
2744 </section>
2745
2746<section title="Since draft-ietf-httpbis-p3-payload-04" anchor="changes.since.04">
2747<t>
2748  Closed issues:
2749  <list style="symbols"> 
2750    <t>
2751      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/132"/>:
2752      "RFC 2822 is updated by RFC 5322"
2753    </t>
2754  </list>
2755</t>
2756<t>
2757  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2758  <list style="symbols"> 
2759    <t>
2760      Use "/" instead of "|" for alternatives.
2761    </t>
2762    <t>
2763      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
2764      whitespace ("OWS") and required whitespace ("RWS").
2765    </t>
2766    <t>
2767      Rewrite ABNFs to spell out whitespace rules, factor out
2768      header field value format definitions.
2769    </t>
2770  </list>
2771</t>
2772</section>
2773
2774<section title="Since draft-ietf-httpbis-p3-payload-05" anchor="changes.since.05">
2775<t>
2776  Closed issues:
2777  <list style="symbols"> 
2778    <t>
2779      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/118"/>:
2780      "Join "Differences Between HTTP Entities and RFC 2045 Entities"?"
2781    </t>
2782  </list>
2783</t>
2784<t>
2785  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2786  <list style="symbols"> 
2787    <t>
2788      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
2789    </t>
2790  </list>
2791</t>
2792<t>
2793  Other changes:
2794  <list style="symbols"> 
2795    <t>
2796      Move definition of quality values into Part 1.
2797    </t>
2798  </list>
2799</t>
2800</section>
2801
2802<section title="Since draft-ietf-httpbis-p3-payload-06" anchor="changes.since.06">
2803<t>
2804  Closed issues:
2805  <list style="symbols"> 
2806    <t>
2807      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>:
2808      "Content-Location isn't special"
2809    </t>
2810    <t>
2811      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2812      "Content Sniffing"
2813    </t>
2814  </list>
2815</t>
2816</section>
2817
2818<section title="Since draft-ietf-httpbis-p3-payload-07" anchor="changes.since.07">
2819<t>
2820  Closed issues:
2821  <list style="symbols"> 
2822    <t>
2823      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/13"/>:
2824      "Updated reference for language tags"
2825    </t>
2826    <t>
2827      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/110"/>:
2828      "Clarify rules for determining what entities a response carries"
2829    </t>
2830    <t>
2831      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/154"/>:
2832      "Content-Location base-setting problems"
2833    </t>
2834    <t>
2835      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2836      "Content Sniffing"
2837    </t>
2838    <t>
2839      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/188"/>:
2840      "pick IANA policy (RFC5226) for Transfer Coding / Content Coding"
2841    </t>
2842    <t>
2843      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/189"/>:
2844      "move definitions of gzip/deflate/compress to part 1"
2845    </t>
2846  </list>
2847</t>
2848<t>
2849  Partly resolved issues:
2850  <list style="symbols"> 
2851    <t>
2852      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/148"/>:
2853      "update IANA requirements wrt Transfer-Coding values" (add the
2854      IANA Considerations subsection)
2855    </t>
2856    <t>
2857      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/149"/>:
2858      "update IANA requirements wrt Content-Coding values" (add the
2859      IANA Considerations subsection)
2860    </t>
2861  </list>
2862</t>
2863</section>
2864
2865<section title="Since draft-ietf-httpbis-p3-payload-08" anchor="changes.since.08">
2866<t>
2867  Closed issues:
2868  <list style="symbols"> 
2869    <t>
2870      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/81"/>:
2871      "Content Negotiation for media types"
2872    </t>
2873    <t>
2874      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/181"/>:
2875      "Accept-Language: which RFC4647 filtering?"
2876    </t>
2877  </list>
2878</t>
2879</section>
2880
2881<section title="Since draft-ietf-httpbis-p3-payload-09" anchor="changes.since.09">
2882<t>
2883  Closed issues:
2884  <list style="symbols"> 
2885    <t>
2886      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/122"/>:
2887      "MIME-Version not listed in P1, general header fields"
2888    </t>
2889    <t>
2890      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/143"/>:
2891      "IANA registry for content/transfer encodings"
2892    </t>
2893    <t>
2894      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2895      "Content Sniffing"
2896    </t>
2897    <t>
2898      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/200"/>:
2899      "use of term "word" when talking about header structure"
2900    </t>
2901  </list>
2902</t>
2903<t>
2904  Partly resolved issues:
2905  <list style="symbols"> 
2906    <t>
2907      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/196"/>:
2908      "Term for the requested resource's URI"
2909    </t>
2910  </list>
2911</t>
2912</section>
2913
2914<section title="Since draft-ietf-httpbis-p3-payload-10" anchor="changes.since.10">
2915<t>
2916  Closed issues:
2917  <list style="symbols"> 
2918    <t>
2919      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
2920      "Clarify 'Requested Variant'"
2921    </t>
2922    <t>
2923      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>:
2924      "Content-Location isn't special"
2925    </t>
2926    <t>
2927      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/90"/>:
2928      "Delimiting messages with multipart/byteranges"
2929    </t>
2930    <t>
2931      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
2932      "Clarify entity / representation / variant terminology"
2933    </t>
2934    <t>
2935      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/136"/>:
2936      "confusing req. language for Content-Location"
2937    </t>
2938    <t>
2939      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/167"/>:
2940      "Content-Location on 304 responses"
2941    </t>
2942    <t>
2943      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/183"/>:
2944      "'requested resource' in content-encoding definition"
2945    </t>
2946    <t>
2947      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
2948      "consider removing the 'changes from 2068' sections"
2949    </t>
2950  </list>
2951</t>
2952<t>
2953  Partly resolved issues:
2954  <list style="symbols"> 
2955    <t>
2956      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>:
2957      "Content-MD5 and partial responses"
2958    </t>
2959  </list>
2960</t>
2961</section>
2962
2963<section title="Since draft-ietf-httpbis-p3-payload-11" anchor="changes.since.11">
2964<t>
2965  Closed issues:
2966  <list style="symbols"> 
2967    <t>
2968      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/123"/>:
2969      "Factor out Content-Disposition"
2970    </t>
2971  </list>
2972</t>
2973</section>
2974
2975<section title="Since draft-ietf-httpbis-p3-payload-12" anchor="changes.since.12">
2976<t>
2977  Closed issues:
2978  <list style="symbols"> 
2979    <t>
2980      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
2981      "Header Classification"
2982    </t>
2983    <t>
2984      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
2985      "untangle ABNFs for header fields"
2986    </t>
2987    <t>
2988      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/277"/>:
2989      "potentially misleading MAY in media-type def"
2990    </t>
2991  </list>
2992</t>
2993</section>
2994
2995<section title="Since draft-ietf-httpbis-p3-payload-13" anchor="changes.since.13">
2996<t>
2997  Closed issues:
2998  <list style="symbols"> 
2999    <t>
3000      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/20"/>:
3001      "Default charsets for text media types"
3002    </t>
3003    <t>
3004      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>:
3005      "Content-MD5 and partial responses"
3006    </t>
3007    <t>
3008      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
3009      "untangle ABNFs for header fields"
3010    </t>
3011    <t>
3012      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/281"/>:
3013      "confusing undefined parameter in media range example"
3014    </t>
3015  </list>
3016</t>
3017</section>
3018
3019<section title="Since draft-ietf-httpbis-p3-payload-14" anchor="changes.since.14">
3020<t>
3021  None.
3022</t>
3023</section>
3024
3025<section title="Since draft-ietf-httpbis-p3-payload-15" anchor="changes.since.15">
3026<t>
3027  Closed issues:
3028  <list style="symbols"> 
3029    <t>
3030      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/285"/>:
3031      "Strength of requirements on Accept re: 406"
3032    </t>
3033  </list>
3034</t>
3035</section>
3036
3037</section>
3038
3039</back>
3040</rfc>
Note: See TracBrowser for help on using the repository browser.