source: draft-ietf-httpbis/18/p3-payload.xml @ 1499

Last change on this file since 1499 was 1499, checked in by julian.reschke@…, 8 years ago

prepare for publication of -18 on Jan 04.

  • Property svn:eol-style set to native
File size: 125.3 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 "18">
15  <!ENTITY ID-MONTH "January">
16  <!ENTITY ID-YEAR "2012">
17  <!ENTITY mdash "&#8212;">
18  <!ENTITY architecture             "<xref target='Part1' x:rel='#architecture' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
19  <!ENTITY notation                 "<xref target='Part1' x:rel='#notation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
20  <!ENTITY notation-abnf            "<xref target='Part1' x:rel='#notation.abnf' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
21  <!ENTITY acks                     "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
22  <!ENTITY basic-rules              "<xref target='Part1' x:rel='#basic.rules' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY field-rules              "<xref target='Part1' x:rel='#field.rules' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY caching-neg-resp         "<xref target='Part6' x:rel='#caching.negotiated.responses' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY header-transfer-encoding "<xref target='Part1' x:rel='#header.transfer-encoding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY header-content-length    "<xref target='Part1' x:rel='#header.content-length' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY header-content-range     "<xref target='Part5' x:rel='#header.content-range' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY header-expires           "<xref target='Part6' x:rel='#header.expires' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29  <!ENTITY header-last-modified     "<xref target='Part4' x:rel='#header.last-modified' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
30  <!ENTITY header-user-agent        "<xref target='Part2' x:rel='#header.user-agent' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
31  <!ENTITY header-vary              "<xref target='Part6' x:rel='#header.vary' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
32  <!ENTITY message-body             "<xref target='Part1' x:rel='#message.body' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
33  <!ENTITY multipart-byteranges     "<xref target='Part5' x:rel='#internet.media.type.multipart.byteranges' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
34  <!ENTITY http-date                "<xref target='Part2' x:rel='#http.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
35  <!ENTITY qvalue                   "<xref target='Part1' x:rel='#quality.values' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
36  <!ENTITY uri                      "<xref target='Part1' x:rel='#uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
37  <!ENTITY effective-request-uri    "<xref target='Part1' x:rel='#effective.request.uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
38  <!ENTITY compression-codings      "<xref target='Part1' x:rel='#compression.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
39  <!ENTITY transfer-codings         "<xref target='Part1' x:rel='#transfer.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
40  <!ENTITY compress-coding          "<xref target='Part1' x:rel='#compress.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
41  <!ENTITY deflate-coding           "<xref target='Part1' x:rel='#deflate.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
42  <!ENTITY gzip-coding              "<xref target='Part1' x:rel='#gzip.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
43  <!ENTITY response-representation  "<xref target='Part2' x:rel='#identifying.response.associated.with.representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
44]>
45<?rfc toc="yes" ?>
46<?rfc symrefs="yes" ?>
47<?rfc sortrefs="yes" ?>
48<?rfc compact="yes"?>
49<?rfc subcompact="no" ?>
50<?rfc linkmailto="no" ?>
51<?rfc editing="no" ?>
52<?rfc comments="yes"?>
53<?rfc inline="yes"?>
54<?rfc rfcedstyle="yes"?>
55<?rfc-ext allow-markup-in-artwork="yes" ?>
56<?rfc-ext include-references-in-index="yes" ?>
57<rfc obsoletes="2616" category="std" x:maturity-level="proposed"
58     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p3-payload-&ID-VERSION;"
59     xmlns:x='http://purl.org/net/xml2rfc/ext'>
60<x:link rel="prev" basename="p2-semantics"/>
61<x:link rel="next" basename="p4-conditional"/>
62<front>
63
64  <title abbrev="HTTP/1.1, Part 3">HTTP/1.1, part 3: Message Payload and Content Negotiation</title>
65
66  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
67    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
68    <address>
69      <postal>
70        <street>345 Park Ave</street>
71        <city>San Jose</city>
72        <region>CA</region>
73        <code>95110</code>
74        <country>USA</country>
75      </postal>
76      <email>fielding@gbiv.com</email>
77      <uri>http://roy.gbiv.com/</uri>
78    </address>
79  </author>
80
81  <author initials="J." surname="Gettys" fullname="Jim Gettys">
82    <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
83    <address>
84      <postal>
85        <street>21 Oak Knoll Road</street>
86        <city>Carlisle</city>
87        <region>MA</region>
88        <code>01741</code>
89        <country>USA</country>
90      </postal>
91      <email>jg@freedesktop.org</email>
92      <uri>http://gettys.wordpress.com/</uri>
93    </address>
94  </author>
95 
96  <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
97    <organization abbrev="HP">Hewlett-Packard Company</organization>
98    <address>
99      <postal>
100        <street>HP Labs, Large Scale Systems Group</street>
101        <street>1501 Page Mill Road, MS 1177</street>
102        <city>Palo Alto</city>
103        <region>CA</region>
104        <code>94304</code>
105        <country>USA</country>
106      </postal>
107      <email>JeffMogul@acm.org</email>
108    </address>
109  </author>
110
111  <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
112    <organization abbrev="Microsoft">Microsoft Corporation</organization>
113    <address>
114      <postal>
115        <street>1 Microsoft Way</street>
116        <city>Redmond</city>
117        <region>WA</region>
118        <code>98052</code>
119        <country>USA</country>
120      </postal>
121      <email>henrikn@microsoft.com</email>
122    </address>
123  </author>
124
125  <author initials="L." surname="Masinter" fullname="Larry Masinter">
126    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
127    <address>
128      <postal>
129        <street>345 Park Ave</street>
130        <city>San Jose</city>
131        <region>CA</region>
132        <code>95110</code>
133        <country>USA</country>
134      </postal>
135      <email>LMM@acm.org</email>
136      <uri>http://larry.masinter.net/</uri>
137    </address>
138  </author>
139 
140  <author initials="P." surname="Leach" fullname="Paul J. Leach">
141    <organization abbrev="Microsoft">Microsoft Corporation</organization>
142    <address>
143      <postal>
144        <street>1 Microsoft Way</street>
145        <city>Redmond</city>
146        <region>WA</region>
147        <code>98052</code>
148      </postal>
149      <email>paulle@microsoft.com</email>
150    </address>
151  </author>
152   
153  <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
154    <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
155    <address>
156      <postal>
157        <street>MIT Computer Science and Artificial Intelligence Laboratory</street>
158        <street>The Stata Center, Building 32</street>
159        <street>32 Vassar Street</street>
160        <city>Cambridge</city>
161        <region>MA</region>
162        <code>02139</code>
163        <country>USA</country>
164      </postal>
165      <email>timbl@w3.org</email>
166      <uri>http://www.w3.org/People/Berners-Lee/</uri>
167    </address>
168  </author>
169
170  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
171    <organization abbrev="W3C">World Wide Web Consortium</organization>
172    <address>
173      <postal>
174        <street>W3C / ERCIM</street>
175        <street>2004, rte des Lucioles</street>
176        <city>Sophia-Antipolis</city>
177        <region>AM</region>
178        <code>06902</code>
179        <country>France</country>
180      </postal>
181      <email>ylafon@w3.org</email>
182      <uri>http://www.raubacapeu.net/people/yves/</uri>
183    </address>
184  </author>
185
186  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
187    <organization abbrev="greenbytes">greenbytes GmbH</organization>
188    <address>
189      <postal>
190        <street>Hafenweg 16</street>
191        <city>Muenster</city><region>NW</region><code>48155</code>
192        <country>Germany</country>
193      </postal>
194      <phone>+49 251 2807760</phone>
195      <facsimile>+49 251 2807761</facsimile>
196      <email>julian.reschke@greenbytes.de</email>
197      <uri>http://greenbytes.de/tech/webdav/</uri>
198    </address>
199  </author>
200
201  <date month="&ID-MONTH;" year="&ID-YEAR;" day="4"/>
202  <workgroup>HTTPbis Working Group</workgroup>
203
204<abstract>
205<t>
206   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
207   distributed, collaborative, hypertext information systems. HTTP has been in
208   use by the World Wide Web global information initiative since 1990. This
209   document is Part 3 of the seven-part specification that defines the protocol
210   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
211</t>
212<t>
213   Part 3 defines HTTP message content, metadata, and content negotiation.
214</t>
215</abstract>
216
217<note title="Editorial Note (To be removed by RFC Editor)">
218  <t>
219    Discussion of this draft should take place on the HTTPBIS working group
220    mailing list (ietf-http-wg@w3.org), which is archived at
221    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
222  </t>
223  <t>
224    The current issues list is at
225    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
226    documents (including fancy diffs) can be found at
227    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
228  </t>
229  <t>
230    The changes in this draft are summarized in <xref target="changes.since.17"/>.
231  </t>
232</note>
233</front>
234<middle>
235<section title="Introduction" anchor="introduction">
236<t>
237   This document defines HTTP/1.1 message payloads (a.k.a., content), the
238   associated metadata header fields that define how the payload is intended
239   to be interpreted by a recipient, the request header fields that
240   might influence content selection, and the various selection algorithms
241   that are collectively referred to as HTTP content negotiation.
242</t>
243<t>
244   This document is currently disorganized in order to minimize the changes
245   between drafts and enable reviewers to see the smaller errata changes.
246   A future draft will reorganize the sections to better reflect the content.
247   In particular, the sections on entities will be renamed payload and moved
248   to the first half of the document, while the sections on content negotiation
249   and associated request header fields will be moved to the second half.  The
250   current mess reflects how widely dispersed these topics and associated
251   requirements had become in <xref target="RFC2616"/>.
252</t>
253
254<section title="Terminology" anchor="terminology">
255<t>
256   This specification uses a number of terms to refer to the roles
257   played by participants in, and objects of, the HTTP communication.
258</t>
259<t>
260  <iref item="content negotiation"/>
261  <x:dfn>content negotiation</x:dfn>
262  <list>
263    <t>
264      The mechanism for selecting the appropriate representation when
265      servicing a request. The representation in any response
266      can be negotiated (including error responses).
267    </t>
268  </list>
269</t>
270</section>
271
272<section title="Conformance and Error Handling" anchor="intro.conformance.and.error.handling">
273<t>
274   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
275   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
276   document are to be interpreted as described in <xref target="RFC2119"/>.
277</t>
278<t>
279   This document defines conformance criteria for several roles in HTTP
280   communication, including Senders, Recipients, Clients, Servers, User-Agents,
281   Origin Servers, Intermediaries, Proxies and Gateways. See &architecture;
282   for definitions of these terms.
283</t>
284<t>
285   An implementation is considered conformant if it complies with all of the
286   requirements associated with its role(s). Note that SHOULD-level requirements
287   are relevant here, unless one of the documented exceptions is applicable.
288</t>
289<t>
290   This document also uses ABNF to define valid protocol elements
291   (<xref target="notation"/>). In addition to the prose requirements placed
292   upon them, Senders &MUST-NOT; generate protocol elements that are invalid.
293</t>
294<t>
295   Unless noted otherwise, Recipients &MAY; take steps to recover a usable
296   protocol element from an invalid construct. However, HTTP does not define
297   specific error handling mechanisms, except in cases where it has direct
298   impact on security. This is because different uses of the protocol require
299   different error handling strategies; for example, a Web browser may wish to
300   transparently recover from a response where the Location header field
301   doesn't parse according to the ABNF, whereby in a systems control protocol
302   using HTTP, this type of error recovery could lead to dangerous consequences.
303</t>
304</section>
305
306<section title="Syntax Notation" anchor="notation">
307  <x:anchor-alias value="ALPHA"/>
308  <x:anchor-alias value="CR"/>
309  <x:anchor-alias value="DIGIT"/>
310  <x:anchor-alias value="LF"/>
311  <x:anchor-alias value="OCTET"/>
312  <x:anchor-alias value="VCHAR"/>
313<t>
314  This specification uses the ABNF syntax defined in &notation; (which
315  extends the syntax defined in <xref target="RFC5234"/> with a list rule).
316  <xref target="collected.abnf"/> shows the collected ABNF, with the list
317  rule expanded.
318</t>
319<t>
320  The following core rules are included by
321  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
322  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
323  DIGIT (decimal 0-9), DQUOTE (double quote),
324  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
325  OCTET (any 8-bit sequence of data), SP (space), and
326  VCHAR (any visible US-ASCII character).
327</t>
328
329<section title="Core Rules" anchor="core.rules">
330  <x:anchor-alias value="token"/>
331  <x:anchor-alias value="word"/>
332  <x:anchor-alias value="OWS"/>
333<t>
334  The core rules below are defined in <xref target="Part1"/>:
335</t>
336<figure><artwork type="abnf2616">
337  <x:ref>OWS</x:ref>            = &lt;OWS, defined in &basic-rules;&gt;
338  <x:ref>token</x:ref>          = &lt;token, defined in &field-rules;&gt;
339  <x:ref>word</x:ref>           = &lt;word, defined in &field-rules;&gt;
340</artwork></figure>
341</section>
342
343<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
344  <x:anchor-alias value="absolute-URI"/>
345  <x:anchor-alias value="partial-URI"/>
346  <x:anchor-alias value="qvalue"/>
347<t>
348  The ABNF rules below are defined in other parts:
349</t>
350<figure><!--Part1--><artwork type="abnf2616">
351  <x:ref>absolute-URI</x:ref>   = &lt;absolute-URI, defined in &uri;&gt;
352  <x:ref>partial-URI</x:ref>    = &lt;partial-URI, defined in &uri;&gt;
353  <x:ref>qvalue</x:ref>         = &lt;qvalue, defined in &qvalue;&gt;
354</artwork></figure>
355</section>
356
357</section>
358
359</section>
360
361<section title="Protocol Parameters" anchor="protocol.parameters">
362
363<section title="Character Encodings (charset)" anchor="character.sets">
364<t>
365   HTTP uses charset names to indicate the character encoding of a
366   textual representation.
367</t>
368<t anchor="rule.charset">
369  <x:anchor-alias value="charset"/>
370   A character encoding is identified by a case-insensitive token. The
371   complete set of tokens is defined by the IANA Character Set registry
372   (<eref target="http://www.iana.org/assignments/character-sets"/>).
373</t>
374<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="charset"/>
375  <x:ref>charset</x:ref> = <x:ref>token</x:ref>
376</artwork></figure>
377<t>
378   Although HTTP allows an arbitrary token to be used as a charset
379   value, any token that has a predefined value within the IANA
380   Character Set registry &MUST; represent the character encoding defined
381   by that registry. Applications &SHOULD; limit their use of character
382   encodings to those defined within the IANA registry.
383</t>
384<t>
385   HTTP uses charset in two contexts: within an Accept-Charset request
386   header field (in which the charset value is an unquoted token) and as the
387   value of a parameter in a Content-Type header field (within a request or
388   response), in which case the parameter value of the charset parameter
389   can be quoted.
390</t>
391<t>
392   Implementors need to be aware of IETF character set requirements <xref target="RFC3629"/>
393   <xref target="RFC2277"/>.
394</t>
395</section>
396
397<section title="Content Codings" anchor="content.codings">
398  <x:anchor-alias value="content-coding"/>
399<t>
400   Content coding values indicate an encoding transformation that has
401   been or can be applied to a representation. Content codings are primarily
402   used to allow a representation to be compressed or otherwise usefully
403   transformed without losing the identity of its underlying media type
404   and without loss of information. Frequently, the representation is stored in
405   coded form, transmitted directly, and only decoded by the recipient.
406</t>
407<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="content-coding"/>
408  <x:ref>content-coding</x:ref>   = <x:ref>token</x:ref>
409</artwork></figure>
410<t>
411   All content-coding values are case-insensitive. HTTP/1.1 uses
412   content-coding values in the Accept-Encoding (<xref target="header.accept-encoding"/>) and
413   Content-Encoding (<xref target="header.content-encoding"/>) header fields. Although the value
414   describes the content-coding, what is more important is that it
415   indicates what decoding mechanism will be required to remove the
416   encoding.
417</t>
418<t>
419   compress<iref item="compress (Coding Format)"/><iref item="Coding Format" subitem="compress"/>
420  <list>
421    <t>
422      See &compress-coding;.
423    </t>
424  </list>
425</t>
426<t>
427   deflate<iref item="deflate (Coding Format)"/><iref item="Coding Format" subitem="deflate"/>
428  <list>
429    <t>
430      See &deflate-coding;.
431    </t>
432  </list>
433</t>
434<t>
435   gzip<iref item="gzip (Coding Format)"/><iref item="Coding Format" subitem="gzip"/>
436  <list>
437    <t>
438      See &gzip-coding;.
439    </t>
440  </list>
441</t>
442
443<section title="Content Coding Registry" anchor="content.coding.registry">
444<t>
445   The HTTP Content Coding Registry defines the name space for the content
446   coding names.
447</t>
448<t>
449   Registrations &MUST; include the following fields:
450   <list style="symbols">
451     <t>Name</t>
452     <t>Description</t>
453     <t>Pointer to specification text</t>
454   </list>
455</t>
456<t>
457   Names of content codings &MUST-NOT; overlap with names of transfer codings
458   (&transfer-codings;), unless the encoding transformation is identical (as it
459   is the case for the compression codings defined in
460   &compression-codings;).
461</t>
462<t>
463   Values to be added to this name space require a specification
464   (see "Specification Required" in
465   <xref target="RFC5226" x:fmt="of" x:sec="4.1"/>), and &MUST;
466   conform to the purpose of content coding defined in this section.
467</t>
468<t>
469   The registry itself is maintained at
470   <eref target="http://www.iana.org/assignments/http-parameters"/>.
471</t>
472</section>
473
474</section>
475
476<section title="Media Types" anchor="media.types">
477  <x:anchor-alias value="media-type"/>
478  <x:anchor-alias value="type"/>
479  <x:anchor-alias value="subtype"/>
480<t>
481   HTTP uses Internet Media Types <xref target="RFC2046"/> in the Content-Type (<xref target="header.content-type"/>)
482   and Accept (<xref target="header.accept"/>) header fields in order to provide
483   open and extensible data typing and type negotiation.
484</t>
485<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"/>
486  <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> )
487  <x:ref>type</x:ref>       = <x:ref>token</x:ref>
488  <x:ref>subtype</x:ref>    = <x:ref>token</x:ref>
489</artwork></figure>
490<t anchor="rule.parameter">
491  <x:anchor-alias value="attribute"/>
492  <x:anchor-alias value="parameter"/>
493  <x:anchor-alias value="value"/>
494   The type/subtype &MAY; be followed by parameters in the form of
495   attribute/value pairs.
496</t>
497<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"/>
498  <x:ref>parameter</x:ref>      = <x:ref>attribute</x:ref> "=" <x:ref>value</x:ref>
499  <x:ref>attribute</x:ref>      = <x:ref>token</x:ref>
500  <x:ref>value</x:ref>          = <x:ref>word</x:ref>
501</artwork></figure>
502<t>
503   The type, subtype, and parameter attribute names are case-insensitive.
504   Parameter values might or might not be case-sensitive, depending on the
505   semantics of the parameter name.  The presence or absence of a parameter might
506   be significant to the processing of a media-type, depending on its
507   definition within the media type registry.
508</t>
509<t>
510   A parameter value that matches the <x:ref>token</x:ref> production can be
511   transmitted as either a token or within a quoted-string. The quoted and
512   unquoted values are equivalent.
513</t>
514<t>
515   Note that some older HTTP applications do not recognize media type
516   parameters. When sending data to older HTTP applications,
517   implementations &SHOULD; only use media type parameters when they are
518   required by that type/subtype definition.
519</t>
520<t>
521   Media-type values are registered with the Internet Assigned Number
522   Authority (IANA). The media type registration process is
523   outlined in <xref target="RFC4288"/>. Use of non-registered media types is
524   discouraged.
525</t>
526
527<section title="Canonicalization and Text Defaults" anchor="canonicalization.and.text.defaults">
528<t>
529   Internet media types are registered with a canonical form. A
530   representation transferred via HTTP messages &MUST; be in the
531   appropriate canonical form prior to its transmission except for
532   "text" types, as defined in the next paragraph.
533</t>
534<t>
535   When in canonical form, media subtypes of the "text" type use CRLF as
536   the text line break. HTTP relaxes this requirement and allows the
537   transport of text media with plain CR or LF alone representing a line
538   break when it is done consistently for an entire representation. HTTP
539   applications &MUST; accept CRLF, bare CR, and bare LF as indicating
540   a line break in text media received via HTTP. In
541   addition, if the text is in a character encoding that does not
542   use octets 13 and 10 for CR and LF respectively, as is the case for
543   some multi-byte character encodings, HTTP allows the use of whatever octet
544   sequences are defined by that character encoding to represent the
545   equivalent of CR and LF for line breaks. This flexibility regarding
546   line breaks applies only to text media in the payload body; a bare CR
547   or LF &MUST-NOT; be substituted for CRLF within any of the HTTP control
548   structures (such as header fields and multipart boundaries).
549</t>
550<t>
551   If a representation is encoded with a content-coding, the underlying
552   data &MUST; be in a form defined above prior to being encoded.
553</t>
554</section>
555
556<section title="Multipart Types" anchor="multipart.types">
557<t>
558   MIME provides for a number of "multipart" types &mdash; encapsulations of
559   one or more representations within a single message-body. All multipart
560   types share a common syntax, as defined in <xref target="RFC2046" x:sec="5.1.1" x:fmt="of"/>,
561   and &MUST; include a boundary parameter as part of the media type
562   value. The message body is itself a protocol element and &MUST;
563   therefore use only CRLF to represent line breaks between body-parts.
564</t>
565<t>
566   In general, HTTP treats a multipart message-body no differently than
567   any other media type: strictly as payload.  HTTP does not use the
568   multipart boundary as an indicator of message-body length.
569   <!-- jre: re-insert removed text pointing to caching? -->
570   In all other respects, an HTTP user agent &SHOULD; follow the same or similar
571   behavior as a MIME user agent would upon receipt of a multipart type.
572   The MIME header fields within each body-part of a multipart message-body
573   do not have any significance to HTTP beyond that defined by
574   their MIME semantics.
575</t>
576<t>
577   If an application receives an unrecognized multipart subtype, the
578   application &MUST; treat it as being equivalent to "multipart/mixed".
579</t>
580<x:note>
581  <t>
582    <x:h>Note:</x:h> The "multipart/form-data" type has been specifically defined
583    for carrying form data suitable for processing via the POST
584    request method, as described in <xref target="RFC2388"/>.
585  </t>
586</x:note>
587</section>
588</section>
589
590<section title="Language Tags" anchor="language.tags">
591  <x:anchor-alias value="language-tag"/>
592<t>
593   A language tag, as defined in <xref target="RFC5646"/>, identifies a
594   natural language spoken, written, or otherwise conveyed by human beings for
595   communication of information to other human beings. Computer languages are
596   explicitly excluded. HTTP uses language tags within the Accept-Language and
597   Content-Language fields.
598</t>
599<t>
600   In summary, a language tag is composed of one or more parts: A primary
601   language subtag followed by a possibly empty series of subtags:
602</t>
603<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="language-tag"/>
604  <x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in <xref target="RFC5646" x:sec="2.1"/>&gt;
605</artwork></figure>
606<t>
607   White space is not allowed within the tag and all tags are case-insensitive.
608   The name space of language subtags is administered by the IANA (see
609   <eref target="http://www.iana.org/assignments/language-subtag-registry"/>).
610</t>
611<figure>
612  <preamble>Example tags include:</preamble>
613<artwork type="example">
614  en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN
615</artwork>
616</figure>
617<t>
618   See <xref target="RFC5646"/> for further information.
619</t>
620</section>
621</section>
622
623<section title="Payload" anchor="payload">
624<t>
625   HTTP messages &MAY; transfer a payload if not otherwise restricted by
626   the request method or response status code.  The payload consists of
627   metadata, in the form of header fields, and data, in the form of the
628   sequence of octets in the message-body after any transfer-coding has
629   been decoded.
630</t>
631<iref item="payload"/>
632<t>   
633   A "<x:dfn>payload</x:dfn>" in HTTP is always a partial or complete
634   representation of some resource.  We use separate terms for payload
635   and representation because some messages contain only the associated
636   representation's header fields (e.g., responses to HEAD) or only some
637   part(s) of the representation (e.g., the 206 status code).
638</t>
639<section title="Payload Header Fields" anchor="payload.header.fields">
640  <x:anchor-alias value="payload-header"/>
641<t>
642   HTTP header fields that specifically define the payload, rather than the
643   associated representation, are referred to as "payload header fields".
644   The following payload header fields are defined by HTTP/1.1:
645</t>
646<texttable align="left">
647  <ttcol>Header Field Name</ttcol>
648  <ttcol>Defined in...</ttcol>
649
650  <c>Content-Length</c> <c>&header-content-length;</c>
651  <c>Content-Range</c> <c>&header-content-range;</c>
652</texttable>
653</section>
654
655<section title="Payload Body" anchor="payload.body">
656  <x:anchor-alias value="payload-body"/>
657<t>
658   A payload body is only present in a message when a message-body is
659   present, as described in &message-body;. The payload body is obtained
660   from the message-body by decoding any Transfer-Encoding that might
661   have been applied to ensure safe and proper transfer of the message.
662</t>
663</section>
664</section>
665
666<section title="Representation" anchor="representation">
667<iref item="representation"/>
668<t>
669   A "<x:dfn>representation</x:dfn>" is information in a format that can be readily
670   communicated from one party to another.  A resource representation
671   is information that reflects the state of that resource, as observed
672   at some point in the past (e.g., in a response to GET) or to be
673   desired at some point in the future (e.g., in a PUT request).
674</t>
675<t>
676   Most, but not all, representations transferred via HTTP are intended
677   to be a representation of the target resource (the resource identified
678   by the effective request URI).  The precise semantics of a representation
679   are determined by the type of message (request or response), the request
680   method, the response status code, and the representation metadata.
681   For example, the above semantic is true for the representation in any
682   200 (OK) response to GET and for the representation in any PUT request.
683   A 200 response to PUT, in contrast, contains either a representation
684   that describes the successful action or a representation of the target
685   resource, with the latter indicated by a Content-Location header field
686   with the same value as the effective request URI.  Likewise, response
687   messages with an error status code usually contain a representation that
688   describes the error and what next steps are suggested for resolving it.
689</t>
690
691<section title="Representation Header Fields" anchor="representation.header.fields">
692  <x:anchor-alias value="representation-header"/>
693<t>
694   Representation header fields define metadata about the representation data
695   enclosed in the message-body or, if no message-body is present, about
696   the representation that would have been transferred in a 200 response
697   to a simultaneous GET request with the same effective request URI.
698</t>
699<t>
700   The following header fields are defined as representation metadata:
701</t>
702<texttable align="left">
703  <ttcol>Header Field Name</ttcol>
704  <ttcol>Defined in...</ttcol>
705
706  <c>Content-Encoding</c> <c><xref target="header.content-encoding"/></c>
707  <c>Content-Language</c> <c><xref target="header.content-language"/></c>
708  <c>Content-Location</c> <c><xref target="header.content-location"/></c>
709  <c>Content-Type</c> <c><xref target="header.content-type"/></c>
710  <c>Expires</c> <c>&header-expires;</c>
711  <c>Last-Modified</c> <c>&header-last-modified;</c>
712</texttable>
713</section>
714
715<section title="Representation Data" anchor="representation.data">
716  <x:anchor-alias value="representation-data"/>
717<t>
718   The representation body associated with an HTTP message is
719   either provided as the payload body of the message or
720   referred to by the message semantics and the effective request
721   URI.  The representation data is in a format and encoding defined by
722   the representation metadata header fields.
723</t>
724<t>
725   The data type of the representation data
726   is determined via the header fields Content-Type and Content-Encoding.
727   These define a two-layer, ordered encoding model:
728</t>
729<figure><artwork type="example">
730  representation-data := Content-Encoding( Content-Type( bits ) )
731</artwork></figure>
732<t>
733   Content-Type specifies the media type of the underlying data, which
734   defines both the data format and how that data &SHOULD; be processed
735   by the recipient (within the scope of the request method semantics).
736   Any HTTP/1.1 message containing a payload body &SHOULD; include a
737   Content-Type header field defining the media type of the associated
738   representation unless that metadata is unknown to the sender.
739   If the Content-Type header field is not present, it indicates that
740   the sender does not know the media type of the representation;
741   recipients &MAY; either assume that the media type is
742   "application/octet-stream" (<xref target="RFC2046" x:fmt="," x:sec="4.5.1"/>)
743   or examine the content to determine its type.
744</t>
745<t>
746   In practice, resource owners do not always properly configure their origin
747   server to provide the correct Content-Type for a given representation,
748   with the result that some clients will examine a response body's content
749   and override the specified type.
750   Clients that do so risk drawing incorrect conclusions, which might expose
751   additional security risks (e.g., "privilege escalation").  Furthermore,
752   it is impossible to determine the sender's intent by examining the data
753   format: many data formats match multiple media types that differ only in
754   processing semantics.  Implementers are encouraged to provide a means of
755   disabling such "content sniffing" when it is used.
756</t>
757<t>
758   Content-Encoding is used to indicate any additional content
759   codings applied to the data, usually for the purpose of data
760   compression, that are a property of the representation.  If
761   Content-Encoding is not present, then there is no additional
762   encoding beyond that defined by the Content-Type.
763</t>
764</section>
765</section>
766
767<section title="Content Negotiation" anchor="content.negotiation">
768<t>
769   HTTP responses include a representation which contains information for
770   interpretation, whether by a human user or for further processing.
771   Often, the server has different ways of representing the
772   same information; for example, in different formats, languages,
773   or using different character encodings.
774</t>
775<t>
776   HTTP clients and their users might have different or variable
777   capabilities, characteristics or preferences which would influence
778   which representation, among those available from the server,
779   would be best for the server to deliver. For this reason, HTTP
780   provides mechanisms for "content negotiation" &mdash; a process of
781   allowing selection of a representation of a given resource,
782   when more than one is available.
783</t>
784<t>
785   This specification defines two patterns of content negotiation;
786   "server-driven", where the server selects the representation based
787   upon the client's stated preferences, and "agent-driven" negotiation,
788   where the server provides a list of representations for the client to
789   choose from, based upon their metadata. In addition,  there are
790   other patterns: some applications use an "active content" pattern,
791   where the server returns active content which runs on the client
792   and, based on client available parameters, selects additional
793   resources to invoke. "Transparent Content Negotiation" (<xref target="RFC2295"/>)
794   has also been proposed.
795</t>
796<t>
797   These patterns are all widely used, and have trade-offs in applicability
798   and practicality. In particular, when the number of preferences or
799   capabilities to be expressed by a client are large (such as when many
800   different formats are supported by a user-agent), server-driven
801   negotiation becomes unwieldy, and might not be appropriate. Conversely,
802   when the number of representations to choose from is very large,
803   agent-driven negotiation might not be appropriate.
804</t>
805<t>
806   Note that in all cases, the supplier of representations has the
807   responsibility for determining which representations might be
808   considered to be the "same information".
809</t>
810
811<section title="Server-driven Negotiation" anchor="server-driven.negotiation">
812<t>
813   If the selection of the best representation for a response is made by
814   an algorithm located at the server, it is called server-driven
815   negotiation. Selection is based on the available representations of
816   the response (the dimensions over which it can vary; e.g., language,
817   content-coding, etc.) and the contents of particular header fields in
818   the request message or on other information pertaining to the request
819   (such as the network address of the client).
820</t>
821<t>
822   Server-driven negotiation is advantageous when the algorithm for
823   selecting from among the available representations is difficult to
824   describe to the user agent, or when the server desires to send its
825   "best guess" to the client along with the first response (hoping to
826   avoid the round-trip delay of a subsequent request if the "best
827   guess" is good enough for the user). In order to improve the server's
828   guess, the user agent &MAY; include request header fields (Accept,
829   Accept-Language, Accept-Encoding, etc.) which describe its
830   preferences for such a response.
831</t>
832<t>
833   Server-driven negotiation has disadvantages:
834  <list style="numbers">
835    <t>
836         It is impossible for the server to accurately determine what
837         might be "best" for any given user, since that would require
838         complete knowledge of both the capabilities of the user agent
839         and the intended use for the response (e.g., does the user want
840         to view it on screen or print it on paper?).
841    </t>
842    <t>
843         Having the user agent describe its capabilities in every
844         request can be both very inefficient (given that only a small
845         percentage of responses have multiple representations) and a
846         potential violation of the user's privacy.
847    </t>
848    <t>
849         It complicates the implementation of an origin server and the
850         algorithms for generating responses to a request.
851    </t>
852    <t>
853         It might limit a public cache's ability to use the same response
854         for multiple user's requests.
855    </t>
856  </list>
857</t>
858<t>
859   Server-driven negotiation allows the user agent to specify its preferences,
860   but it cannot expect responses to always honour them. For example, the origin
861   server might not implement server-driven negotiation, or it might decide that
862   sending a response that doesn't conform to them is better than sending a 406
863   (Not Acceptable) response.
864</t>
865<t>
866   Many of the mechanisms for expressing preferences use quality values to
867   declare relative preference. See &qvalue; for more information.
868</t>
869<t>
870   HTTP/1.1 includes the following header fields for enabling
871   server-driven negotiation through description of user agent
872   capabilities and user preferences: Accept (<xref target="header.accept"/>), Accept-Charset
873   (<xref target="header.accept-charset"/>), Accept-Encoding (<xref target="header.accept-encoding"/>), Accept-Language
874   (<xref target="header.accept-language"/>), and User-Agent (&header-user-agent;).
875   However, an origin server is not limited to these dimensions and &MAY; vary
876   the response based on any aspect of the request, including aspects
877   of the connection (e.g., IP address) or information within extension
878   header fields not defined by this specification.
879</t>
880<x:note>
881  <t>
882    <x:h>Note:</x:h> In practice, User-Agent based negotiation is fragile,
883    because new clients might not be recognized.
884  </t>
885</x:note>
886<t>
887   The Vary header field (&header-vary;) can be used to express the parameters the
888   server uses to select a representation that is subject to server-driven
889   negotiation.
890</t>
891</section>
892
893<section title="Agent-driven Negotiation" anchor="agent-driven.negotiation">
894<t>
895   With agent-driven negotiation, selection of the best representation
896   for a response is performed by the user agent after receiving an
897   initial response from the origin server. Selection is based on a list
898   of the available representations of the response included within the
899   header fields or body of the initial response, with each
900   representation identified by its own URI. Selection from among the
901   representations can be performed automatically (if the user agent is
902   capable of doing so) or manually by the user selecting from a
903   generated (possibly hypertext) menu.
904</t>
905<t>
906   Agent-driven negotiation is advantageous when the response would vary
907   over commonly-used dimensions (such as type, language, or encoding),
908   when the origin server is unable to determine a user agent's
909   capabilities from examining the request, and generally when public
910   caches are used to distribute server load and reduce network usage.
911</t>
912<t>
913   Agent-driven negotiation suffers from the disadvantage of needing a
914   second request to obtain the best alternate representation. This
915   second request is only efficient when caching is used. In addition,
916   this specification does not define any mechanism for supporting
917   automatic selection, though it also does not prevent any such
918   mechanism from being developed as an extension and used within
919   HTTP/1.1.
920</t>
921<t>
922   This specification defines the 300 (Multiple Choices) and 406 (Not Acceptable)
923   status codes for enabling agent-driven negotiation when the server is
924   unwilling or unable to provide a varying response using server-driven
925   negotiation.
926</t>
927</section>
928</section>
929
930<section title="Header Field Definitions" anchor="header.field.definitions">
931<t>
932   This section defines the syntax and semantics of HTTP/1.1 header fields
933   related to the payload of messages.
934</t>
935
936<section title="Accept" anchor="header.accept">
937  <iref primary="true" item="Accept header field" x:for-anchor=""/>
938  <iref primary="true" item="Header Fields" subitem="Accept" x:for-anchor=""/>
939  <x:anchor-alias value="Accept"/>
940  <x:anchor-alias value="accept-ext"/>
941  <x:anchor-alias value="accept-params"/>
942  <x:anchor-alias value="media-range"/>
943<t>
944   The "Accept" header field can be used by user agents to specify
945   response media types that are acceptable. Accept header fields can be used to
946   indicate that the request is specifically limited to a small set of desired
947   types, as in the case of a request for an in-line image.
948</t>
949<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"/>
950  <x:ref>Accept</x:ref> = #( <x:ref>media-range</x:ref> [ <x:ref>accept-params</x:ref> ] )
951 
952  <x:ref>media-range</x:ref>    = ( "*/*"
953                   / ( <x:ref>type</x:ref> "/" "*" )
954                   / ( <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> )
955                   ) *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> )
956  <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> )
957  <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> ]
958</artwork></figure>
959<t>
960   The asterisk "*" character is used to group media types into ranges,
961   with "*/*" indicating all media types and "type/*" indicating all
962   subtypes of that type. The media-range &MAY; include media type
963   parameters that are applicable to that range.
964</t>
965<t>
966   Each media-range &MAY; be followed by one or more accept-params,
967   beginning with the "q" parameter for indicating a relative quality
968   factor. The first "q" parameter (if any) separates the media-range
969   parameter(s) from the accept-params. Quality factors allow the user
970   or user agent to indicate the relative degree of preference for that
971   media-range, using the qvalue scale from 0 to 1 (&qvalue;). The
972   default value is q=1.
973</t>
974<x:note>
975  <t>
976    <x:h>Note:</x:h> Use of the "q" parameter name to separate media type
977    parameters from Accept extension parameters is due to historical
978    practice. Although this prevents any media type parameter named
979    "q" from being used with a media range, such an event is believed
980    to be unlikely given the lack of any "q" parameters in the IANA
981    media type registry and the rare usage of any media type
982    parameters in Accept. Future media types are discouraged from
983    registering any parameter named "q".
984  </t>
985</x:note>
986<t>
987   The example
988</t>
989<figure><artwork type="example">
990  Accept: audio/*; q=0.2, audio/basic
991</artwork></figure>
992<t>
993   &SHOULD; be interpreted as "I prefer audio/basic, but send me any audio
994   type if it is the best available after an 80% mark-down in quality".
995</t>
996<t>
997   A request without any Accept header field implies that the user agent
998   will accept any media type in response.
999   If an Accept header field is present in a request and none of the
1000   available representations for the response have a media type that is
1001   listed as acceptable, the origin server &MAY; either
1002   honor the Accept header field by sending a 406 (Not Acceptable) response
1003   or disregard the Accept header field by treating the response as if
1004   it is not subject to content negotiation.
1005</t>
1006<t>
1007   A more elaborate example is
1008</t>
1009<figure><artwork type="example">
1010  Accept: text/plain; q=0.5, text/html,
1011          text/x-dvi; q=0.8, text/x-c
1012</artwork></figure>
1013<t>
1014   Verbally, this would be interpreted as "text/html and text/x-c are
1015   the preferred media types, but if they do not exist, then send the
1016   text/x-dvi representation, and if that does not exist, send the text/plain
1017   representation".
1018</t>
1019<t>
1020   Media ranges can be overridden by more specific media ranges or
1021   specific media types. If more than one media range applies to a given
1022   type, the most specific reference has precedence. For example,
1023</t>
1024<figure><artwork type="example">
1025  Accept: text/*, text/plain, text/plain;format=flowed, */*
1026</artwork></figure>
1027<t>
1028   have the following precedence:
1029   <list style="numbers">
1030    <t>text/plain;format=flowed</t>
1031    <t>text/plain</t>
1032    <t>text/*</t>
1033    <t>*/*</t>
1034   </list>
1035</t>
1036<t>
1037   The media type quality factor associated with a given type is
1038   determined by finding the media range with the highest precedence
1039   which matches that type. For example,
1040</t>
1041<figure><artwork type="example">
1042  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
1043          text/html;level=2;q=0.4, */*;q=0.5
1044</artwork></figure>
1045<t>
1046   would cause the following values to be associated:
1047</t>
1048<texttable align="left">
1049  <ttcol>Media Type</ttcol><ttcol>Quality Value</ttcol>
1050  <c>text/html;level=1</c>    <c>1</c>
1051  <c>text/html</c>            <c>0.7</c>
1052  <c>text/plain</c>           <c>0.3</c>
1053  <c>image/jpeg</c>           <c>0.5</c>
1054  <c>text/html;level=2</c>    <c>0.4</c>
1055  <c>text/html;level=3</c>    <c>0.7</c>
1056</texttable>
1057<t>
1058      <x:h>Note:</x:h> A user agent might be provided with a default set of quality
1059      values for certain media ranges. However, unless the user agent is
1060      a closed system which cannot interact with other rendering agents,
1061      this default set ought to be configurable by the user.
1062</t>
1063</section>
1064
1065<section title="Accept-Charset" anchor="header.accept-charset">
1066  <iref primary="true" item="Accept-Charset header field" x:for-anchor=""/>
1067  <iref primary="true" item="Header Fields" subitem="Accept-Charset" x:for-anchor=""/>
1068  <x:anchor-alias value="Accept-Charset"/>
1069<t>
1070   The "Accept-Charset" header field can be used by user agents to
1071   indicate what character encodings are acceptable in a response
1072   payload. This field allows
1073   clients capable of understanding more comprehensive or special-purpose
1074   character encodings to signal that capability to a server which is capable of
1075   representing documents in those character encodings.
1076</t>
1077<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Charset"/>
1078  <x:ref>Accept-Charset</x:ref> = 1#( ( <x:ref>charset</x:ref> / "*" )
1079                         [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1080</artwork></figure>
1081<t>
1082   Character encoding values (a.k.a., charsets) are described in
1083   <xref target="character.sets"/>. Each charset &MAY; be given an
1084   associated quality value which represents the user's preference
1085   for that charset. The default value is q=1. An example is
1086</t>
1087<figure><artwork type="example">
1088  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
1089</artwork></figure>
1090<t>
1091   The special value "*", if present in the Accept-Charset field,
1092   matches every character encoding which is not mentioned elsewhere in the
1093   Accept-Charset field. If no "*" is present in an Accept-Charset field, then
1094   all character encodings not explicitly mentioned get a quality value of 0.
1095</t>
1096<t>
1097   A request without any Accept-Charset header field implies that the user
1098   agent will accept any character encoding in response.
1099   If an Accept-Charset header field is present in a request and none of the
1100   available representations for the response have a character encoding that
1101   is listed as acceptable, the origin server &MAY; either honor the
1102   Accept-Charset header field by sending a 406 (Not Acceptable) response or
1103   disregard the Accept-Charset header field by treating the response as if
1104   it is not subject to content negotiation.
1105</t>
1106</section>
1107
1108<section title="Accept-Encoding" anchor="header.accept-encoding">
1109  <iref primary="true" item="Accept-Encoding header field" x:for-anchor=""/>
1110  <iref primary="true" item="Header Fields" subitem="Accept-Encoding" x:for-anchor=""/>
1111  <x:anchor-alias value="Accept-Encoding"/>
1112  <x:anchor-alias value="codings"/>
1113<t>
1114   The "Accept-Encoding" header field can be used by user agents to
1115   indicate what response content-codings (<xref target="content.codings"/>)
1116   are acceptable in the response.  An "identity" token is used as a synonym
1117   for "no encoding" in order to communicate when no encoding is preferred.
1118</t>
1119<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Encoding"/><iref primary="true" item="Grammar" subitem="codings"/>
1120  <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> ] )
1121  <x:ref>codings</x:ref>          = <x:ref>content-coding</x:ref> / "identity" / "*"
1122</artwork></figure>
1123<t>
1124   Each codings value &MAY; be given an associated quality value which
1125   represents the preference for that encoding. The default value is q=1.
1126</t>
1127<t>
1128   For example,
1129</t>
1130<figure><artwork type="example">
1131  Accept-Encoding: compress, gzip
1132  Accept-Encoding:
1133  Accept-Encoding: *
1134  Accept-Encoding: compress;q=0.5, gzip;q=1.0
1135  Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
1136</artwork></figure>
1137<t>
1138   A server tests whether a content-coding for a given representation is
1139   acceptable, according to an Accept-Encoding field, using these rules:
1140  <list style="numbers">
1141      <t>The special "*" symbol in an Accept-Encoding field matches any
1142         available content-coding not explicitly listed in the header
1143         field.</t>
1144
1145      <t>If the representation has no content-coding, then it is acceptable
1146         by default unless specifically excluded by the Accept-Encoding field
1147         stating either "identity;q=0" or "*;q=0" without a more specific
1148         entry for "identity".</t>
1149
1150      <t>If the representation's content-coding is one of the content-codings
1151         listed in the Accept-Encoding field, then it is acceptable unless
1152         it is accompanied by a qvalue of 0. (As defined in &qvalue;, a
1153         qvalue of 0 means "not acceptable".)</t>
1154
1155      <t>If multiple content-codings are acceptable, then the acceptable
1156         content-coding with the highest non-zero qvalue is preferred.</t>
1157  </list>
1158</t>
1159<t>
1160   An Accept-Encoding header field with a combined field-value that is empty
1161   implies that the user agent does not want any content-coding in response.
1162   If an Accept-Encoding header field is present in a request and none of the
1163   available representations for the response have a content-coding that
1164   is listed as acceptable, the origin server &SHOULD; send a response
1165   without any content-coding.
1166</t>
1167<t>
1168   A request without an Accept-Encoding header field implies that the user
1169   agent will accept any content-coding in response, but a representation
1170   without content-coding is preferred for compatibility with the widest
1171   variety of user agents.
1172</t>
1173<x:note>
1174  <t>
1175    <x:h>Note:</x:h> Most HTTP/1.0 applications do not recognize or obey qvalues
1176    associated with content-codings. This means that qvalues will not
1177    work and are not permitted with x-gzip or x-compress.
1178  </t>
1179</x:note>
1180</section>
1181
1182<section title="Accept-Language" anchor="header.accept-language">
1183  <iref primary="true" item="Accept-Language header field" x:for-anchor=""/>
1184  <iref primary="true" item="Header Fields" subitem="Accept-Language" x:for-anchor=""/>
1185  <x:anchor-alias value="Accept-Language"/>
1186  <x:anchor-alias value="language-range"/>
1187<t>
1188   The "Accept-Language" header field can be used by user agents to
1189   indicate the set of natural languages that are preferred in the response.
1190   Language tags are defined in <xref target="language.tags"/>.
1191</t>
1192<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Language"/><iref primary="true" item="Grammar" subitem="language-range"/>
1193  <x:ref>Accept-Language</x:ref> =
1194                    1#( <x:ref>language-range</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
1195  <x:ref>language-range</x:ref>  =
1196            &lt;language-range, defined in <xref target="RFC4647" x:fmt="," x:sec="2.1"/>&gt;
1197</artwork></figure>
1198<t>
1199   Each language-range can be given an associated quality value which
1200   represents an estimate of the user's preference for the languages
1201   specified by that range. The quality value defaults to "q=1". For
1202   example,
1203</t>
1204<figure><artwork type="example">
1205  Accept-Language: da, en-gb;q=0.8, en;q=0.7
1206</artwork></figure>
1207<t>
1208   would mean: "I prefer Danish, but will accept British English and
1209   other types of English".
1210   (see also <xref target="RFC4647" x:sec="2.3" x:fmt="of"/>)
1211</t>
1212<t>
1213   For matching, <xref target="RFC4647" x:sec="3" x:fmt="of"/> defines
1214   several matching schemes. Implementations can offer the most appropriate
1215   matching scheme for their requirements.
1216</t>
1217<x:note>
1218  <t>
1219    <x:h>Note:</x:h> The "Basic Filtering" scheme (<xref target="RFC4647"
1220    x:fmt="," x:sec="3.3.1"/>) is identical to the matching scheme that was
1221    previously defined in <xref target="RFC2616" x:fmt="of" x:sec="14.4"/>.
1222  </t>
1223</x:note>
1224<t>
1225   It might be contrary to the privacy expectations of the user to send
1226   an Accept-Language header field with the complete linguistic preferences of
1227   the user in every request. For a discussion of this issue, see
1228   <xref target="privacy.issues.connected.to.accept.header.fields"/>.
1229</t>
1230<t>
1231   As intelligibility is highly dependent on the individual user, it is
1232   recommended that client applications make the choice of linguistic
1233   preference available to the user. If the choice is not made
1234   available, then the Accept-Language header field &MUST-NOT; be given in
1235   the request.
1236</t>
1237<x:note>
1238  <t>
1239    <x:h>Note:</x:h> When making the choice of linguistic preference available to
1240    the user, we remind implementors of  the fact that users are not
1241    familiar with the details of language matching as described above,
1242    and ought to be provided appropriate guidance. As an example, users
1243    might assume that on selecting "en-gb", they will be served any
1244    kind of English document if British English is not available. A
1245    user agent might suggest in such a case to add "en" to get the
1246    best matching behavior.
1247  </t>
1248</x:note>
1249</section>
1250
1251<section title="Content-Encoding" anchor="header.content-encoding">
1252  <iref primary="true" item="Content-Encoding header field" x:for-anchor=""/>
1253  <iref primary="true" item="Header Fields" subitem="Content-Encoding" x:for-anchor=""/>
1254  <x:anchor-alias value="Content-Encoding"/>
1255<t>
1256   The "Content-Encoding" header field indicates what content-codings
1257   have been applied to the representation beyond those inherent in the media
1258   type, and thus what decoding mechanisms must be applied in order to obtain
1259   the media-type referenced by the Content-Type header field.
1260   Content-Encoding is primarily used to allow a representation to be
1261   compressed without losing the identity of its underlying media type.
1262</t>
1263<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Encoding"/>
1264  <x:ref>Content-Encoding</x:ref> = 1#<x:ref>content-coding</x:ref>
1265</artwork></figure>
1266<t>
1267   Content codings are defined in <xref target="content.codings"/>. An example of its use is
1268</t>
1269<figure><artwork type="example">
1270  Content-Encoding: gzip
1271</artwork></figure>
1272<t>
1273   The content-coding is a characteristic of the representation.
1274   Typically, the representation body is stored with this
1275   encoding and is only decoded before rendering or analogous usage.
1276   However, a transforming proxy &MAY; modify the content-coding if the
1277   new coding is known to be acceptable to the recipient, unless the
1278   "no-transform" cache-control directive is present in the message.
1279</t>
1280<t>
1281   If the media type includes an inherent encoding, such as a data format
1282   that is always compressed, then that encoding would not be restated as
1283   a Content-Encoding even if it happens to be the same algorithm as one
1284   of the content-codings.  Such a content-coding would only be listed if,
1285   for some bizarre reason, it is applied a second time to form the
1286   representation.  Likewise, an origin server might choose to publish the
1287   same payload data as multiple representations that differ only in whether
1288   the coding is defined as part of Content-Type or Content-Encoding, since
1289   some user agents will behave differently in their handling of each
1290   response (e.g., open a "Save as ..." dialog instead of automatic
1291   decompression and rendering of content).
1292</t>
1293<t>
1294   A representation that has a content-coding applied to it &MUST; include
1295   a Content-Encoding header field (<xref target="header.content-encoding"/>)
1296   that lists the content-coding(s) applied.
1297</t>
1298<t>
1299   If multiple encodings have been applied to a representation, the content
1300   codings &MUST; be listed in the order in which they were applied.
1301   Additional information about the encoding parameters &MAY; be provided
1302   by other header fields not defined by this specification.
1303</t>
1304<t>
1305   If the content-coding of a representation in a request message is not
1306   acceptable to the origin server, the server &SHOULD; respond with a
1307   status code of 415 (Unsupported Media Type).
1308</t>
1309</section>
1310
1311<section title="Content-Language" anchor="header.content-language">
1312  <iref primary="true" item="Content-Language header field" x:for-anchor=""/>
1313  <iref primary="true" item="Header Fields" subitem="Content-Language" x:for-anchor=""/>
1314  <x:anchor-alias value="Content-Language"/>
1315<t>
1316   The "Content-Language" header field describes the natural
1317   language(s) of the intended audience for the representation. Note that this might
1318   not be equivalent to all the languages used within the representation.
1319</t>
1320<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Language"/>
1321  <x:ref>Content-Language</x:ref> = 1#<x:ref>language-tag</x:ref>
1322</artwork></figure>
1323<t>
1324   Language tags are defined in <xref target="language.tags"/>. The primary purpose of
1325   Content-Language is to allow a user to identify and differentiate
1326   representations according to the user's own preferred language. Thus, if the
1327   body content is intended only for a Danish-literate audience, the
1328   appropriate field is
1329</t>
1330<figure><artwork type="example">
1331  Content-Language: da
1332</artwork></figure>
1333<t>
1334   If no Content-Language is specified, the default is that the content
1335   is intended for all language audiences. This might mean that the
1336   sender does not consider it to be specific to any natural language,
1337   or that the sender does not know for which language it is intended.
1338</t>
1339<t>
1340   Multiple languages &MAY; be listed for content that is intended for
1341   multiple audiences. For example, a rendition of the "Treaty of
1342   Waitangi", presented simultaneously in the original Maori and English
1343   versions, would call for
1344</t>
1345<figure><artwork type="example">
1346  Content-Language: mi, en
1347</artwork></figure>
1348<t>
1349   However, just because multiple languages are present within a representation
1350   does not mean that it is intended for multiple linguistic audiences.
1351   An example would be a beginner's language primer, such as "A First
1352   Lesson in Latin", which is clearly intended to be used by an
1353   English-literate audience. In this case, the Content-Language would
1354   properly only include "en".
1355</t>
1356<t>
1357   Content-Language &MAY; be applied to any media type &mdash; it is not
1358   limited to textual documents.
1359</t>
1360</section>
1361
1362<section title="Content-Location" anchor="header.content-location">
1363  <iref primary="true" item="Content-Location header field" x:for-anchor=""/>
1364  <iref primary="true" item="Header Fields" subitem="Content-Location" x:for-anchor=""/>
1365  <x:anchor-alias value="Content-Location"/>
1366<t>
1367   The "Content-Location" header field supplies a URI that can be used
1368   as a specific identifier for the representation in this message.
1369   In other words, if one were to perform a GET on this URI at the time
1370   of this message's generation, then a 200 response would contain the
1371   same representation that is enclosed as payload in this message.
1372</t>
1373<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Location"/>
1374  <x:ref>Content-Location</x:ref> = <x:ref>absolute-URI</x:ref> / <x:ref>partial-URI</x:ref>
1375</artwork></figure>
1376<t>
1377   The Content-Location value is not a replacement for the effective
1378   Request URI (&effective-request-uri;).  It is representation metadata.
1379   It has the same syntax and semantics as the header field of the same name
1380   defined for MIME body parts in <xref target="RFC2557" x:fmt="of" x:sec="4"/>.
1381   However, its appearance in an HTTP message has some special implications
1382   for HTTP recipients.
1383</t>
1384<t>
1385   If Content-Location is included in a response message and its value
1386   is the same as the effective request URI, then the response payload
1387   &SHOULD; be considered the current representation of that resource.
1388   For a GET or HEAD request, this is the same as the default semantics
1389   when no Content-Location is provided by the server.  For a state-changing
1390   request like PUT or POST, it implies that the server's response contains
1391   the new representation of that resource, thereby distinguishing it from
1392   representations that might only report about the action (e.g., "It worked!").
1393   This allows authoring applications to update their local copies without
1394   the need for a subsequent GET request.
1395</t>
1396<t>
1397   If Content-Location is included in a response message and its value
1398   differs from the effective request URI, then the origin server is
1399   informing recipients that this representation has its own, presumably
1400   more specific, identifier.  For a GET or HEAD request, this is an
1401   indication that the effective request URI identifies a resource that
1402   is subject to content negotiation and the representation selected for
1403   this response can also be found at the identified URI.  For other
1404   methods, such a Content-Location indicates that this representation
1405   contains a report on the action's status and the same report is
1406   available (for future access with GET) at the given URI.  For
1407   example, a purchase transaction made via a POST request might
1408   include a receipt document as the payload of the 200 response;
1409   the Content-Location value provides an identifier for retrieving
1410   a copy of that same receipt in the future.
1411</t>
1412<t>
1413   If Content-Location is included in a request message, then it &MAY;
1414   be interpreted by the origin server as an indication of where the
1415   user agent originally obtained the content of the enclosed
1416   representation (prior to any subsequent modification of the content
1417   by that user agent).  In other words, the user agent is providing
1418   the same representation metadata that it received with the original
1419   representation.  However, such interpretation &MUST-NOT; be used to
1420   alter the semantics of the method requested by the client.  For
1421   example, if a client makes a PUT request on a negotiated resource
1422   and the origin server accepts that PUT (without redirection), then the
1423   new set of values for that resource is expected to be consistent with
1424   the one representation supplied in that PUT; the Content-Location
1425   cannot be used as a form of reverse content selection that
1426   identifies only one of the negotiated representations to be updated.
1427   If the user agent had wanted the latter semantics, it would have applied
1428   the PUT directly to the Content-Location URI.
1429</t>
1430<t>
1431   A Content-Location field received in a request message is transitory
1432   information that &SHOULD-NOT; be saved with other representation
1433   metadata for use in later responses.  The Content-Location's value
1434   might be saved for use in other contexts, such as within source links
1435   or other metadata.
1436</t>
1437<t>
1438   A cache cannot assume that a representation with a Content-Location
1439   different from the URI used to retrieve it can be used to respond to
1440   later requests on that Content-Location URI.
1441</t>
1442<t>
1443   If the Content-Location value is a partial URI, the partial URI is
1444   interpreted relative to the effective request URI.
1445</t>
1446</section>
1447
1448<section title="Content-Type" anchor="header.content-type">
1449  <iref primary="true" item="Content-Type header field" x:for-anchor=""/>
1450  <iref primary="true" item="Header Fields" subitem="Content-Type" x:for-anchor=""/>
1451  <x:anchor-alias value="Content-Type"/>
1452<t>
1453   The "Content-Type" header field indicates the media type of the
1454   representation. In the case of responses to the HEAD method, the media type is
1455   that which would have been sent had the request been a GET.
1456</t>
1457<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Type"/>
1458  <x:ref>Content-Type</x:ref> = <x:ref>media-type</x:ref>
1459</artwork></figure>
1460<t>
1461   Media types are defined in <xref target="media.types"/>. An example of the field is
1462</t>
1463<figure><artwork type="example">
1464  Content-Type: text/html; charset=ISO-8859-4
1465</artwork></figure>
1466<t>
1467   Further discussion of Content-Type is provided in <xref target="representation.data"/>.
1468</t>
1469</section>
1470
1471</section>
1472
1473<section title="IANA Considerations" anchor="IANA.considerations">
1474<section title="Header Field Registration" anchor="header.field.registration">
1475<t>
1476   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
1477   with the permanent registrations below (see <xref target="RFC3864"/>):
1478</t>
1479<?BEGININC p3-payload.iana-headers ?>
1480<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
1481<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
1482   <ttcol>Header Field Name</ttcol>
1483   <ttcol>Protocol</ttcol>
1484   <ttcol>Status</ttcol>
1485   <ttcol>Reference</ttcol>
1486
1487   <c>Accept</c>
1488   <c>http</c>
1489   <c>standard</c>
1490   <c>
1491      <xref target="header.accept"/>
1492   </c>
1493   <c>Accept-Charset</c>
1494   <c>http</c>
1495   <c>standard</c>
1496   <c>
1497      <xref target="header.accept-charset"/>
1498   </c>
1499   <c>Accept-Encoding</c>
1500   <c>http</c>
1501   <c>standard</c>
1502   <c>
1503      <xref target="header.accept-encoding"/>
1504   </c>
1505   <c>Accept-Language</c>
1506   <c>http</c>
1507   <c>standard</c>
1508   <c>
1509      <xref target="header.accept-language"/>
1510   </c>
1511   <c>Content-Encoding</c>
1512   <c>http</c>
1513   <c>standard</c>
1514   <c>
1515      <xref target="header.content-encoding"/>
1516   </c>
1517   <c>Content-Language</c>
1518   <c>http</c>
1519   <c>standard</c>
1520   <c>
1521      <xref target="header.content-language"/>
1522   </c>
1523   <c>Content-Location</c>
1524   <c>http</c>
1525   <c>standard</c>
1526   <c>
1527      <xref target="header.content-location"/>
1528   </c>
1529   <c>Content-Type</c>
1530   <c>http</c>
1531   <c>standard</c>
1532   <c>
1533      <xref target="header.content-type"/>
1534   </c>
1535   <c>MIME-Version</c>
1536   <c>http</c>
1537   <c>standard</c>
1538   <c>
1539      <xref target="mime-version"/>
1540   </c>
1541</texttable>
1542<!--(END)-->
1543<?ENDINC p3-payload.iana-headers ?>
1544<t>
1545   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
1546</t>
1547</section>
1548
1549<section title="Content Coding Registry" anchor="content.coding.registration">
1550<t>
1551   The registration procedure for HTTP Content Codings is now defined
1552   by <xref target="content.coding.registry"/> of this document.
1553</t>
1554<t>
1555   The HTTP Content Codings Registry located at <eref target="http://www.iana.org/assignments/http-parameters"/>
1556   shall be updated with the registration below:
1557</t>
1558<texttable align="left" suppress-title="true" anchor="iana.content.coding.registration.table">
1559   <ttcol>Name</ttcol>
1560   <ttcol>Description</ttcol>
1561   <ttcol>Reference</ttcol>
1562   <c>compress</c>
1563   <c>UNIX "compress" program method</c>
1564   <c>
1565      &compress-coding;
1566   </c>
1567   <c>deflate</c>
1568   <c>"deflate" compression mechanism (<xref target="RFC1951"/>) used inside
1569   the "zlib" data format (<xref target="RFC1950"/>)
1570   </c>
1571   <c>
1572      &deflate-coding;
1573   </c>
1574   <c>gzip</c>
1575   <c>Same as GNU zip <xref target="RFC1952"/></c>
1576   <c>
1577      &gzip-coding;
1578   </c>
1579   <c>identity</c>
1580   <c>reserved (synonym for "no encoding" in Accept-Encoding header field)</c>
1581   <c>
1582      <xref target="header.accept-encoding"/>
1583   </c>
1584</texttable>
1585</section>
1586
1587</section>
1588
1589<section title="Security Considerations" anchor="security.considerations">
1590<t>
1591   This section is meant to inform application developers, information
1592   providers, and users of the security limitations in HTTP/1.1 as
1593   described by this document. The discussion does not include
1594   definitive solutions to the problems revealed, though it does make
1595   some suggestions for reducing security risks.
1596</t>
1597
1598<section title="Privacy Issues Connected to Accept Header Fields" anchor="privacy.issues.connected.to.accept.header.fields">
1599<t>
1600   Accept headers fields can reveal information about the user to all
1601   servers which are accessed. The Accept-Language header field in particular
1602   can reveal information the user would consider to be of a private
1603   nature, because the understanding of particular languages is often
1604   strongly correlated to the membership of a particular ethnic group.
1605   User agents which offer the option to configure the contents of an
1606   Accept-Language header field to be sent in every request are strongly
1607   encouraged to let the configuration process include a message which
1608   makes the user aware of the loss of privacy involved.
1609</t>
1610<t>
1611   An approach that limits the loss of privacy would be for a user agent
1612   to omit the sending of Accept-Language header fields by default, and to ask
1613   the user whether or not to start sending Accept-Language header fields to a
1614   server if it detects, by looking for any Vary header fields
1615   generated by the server, that such sending could improve the quality
1616   of service.
1617</t>
1618<t>
1619   Elaborate user-customized accept header fields sent in every request,
1620   in particular if these include quality values, can be used by servers
1621   as relatively reliable and long-lived user identifiers. Such user
1622   identifiers would allow content providers to do click-trail tracking,
1623   and would allow collaborating content providers to match cross-server
1624   click-trails or form submissions of individual users. Note that for
1625   many users not behind a proxy, the network address of the host
1626   running the user agent will also serve as a long-lived user
1627   identifier. In environments where proxies are used to enhance
1628   privacy, user agents ought to be conservative in offering accept
1629   header configuration options to end users. As an extreme privacy
1630   measure, proxies could filter the accept header fields in relayed requests.
1631   General purpose user agents which provide a high degree of header
1632   configurability &SHOULD; warn users about the loss of privacy which can
1633   be involved.
1634</t>
1635</section>
1636
1637</section>
1638
1639<section title="Acknowledgments" anchor="acks">
1640<t>
1641  See &acks;.
1642</t>
1643</section>
1644</middle>
1645<back>
1646
1647<references title="Normative References">
1648
1649<reference anchor="Part1">
1650  <front>
1651    <title abbrev="HTTP/1.1">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1652    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1653      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1654      <address><email>fielding@gbiv.com</email></address>
1655    </author>
1656    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1657      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1658      <address><email>jg@freedesktop.org</email></address>
1659    </author>
1660    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1661      <organization abbrev="HP">Hewlett-Packard Company</organization>
1662      <address><email>JeffMogul@acm.org</email></address>
1663    </author>
1664    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1665      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1666      <address><email>henrikn@microsoft.com</email></address>
1667    </author>
1668    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1669      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1670      <address><email>LMM@acm.org</email></address>
1671    </author>
1672    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1673      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1674      <address><email>paulle@microsoft.com</email></address>
1675    </author>
1676    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1677      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1678      <address><email>timbl@w3.org</email></address>
1679    </author>
1680    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1681      <organization abbrev="W3C">World Wide Web Consortium</organization>
1682      <address><email>ylafon@w3.org</email></address>
1683    </author>
1684    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1685      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1686      <address><email>julian.reschke@greenbytes.de</email></address>
1687    </author>
1688    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1689  </front>
1690  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1691  <x:source href="p1-messaging.xml" basename="p1-messaging"/>
1692</reference>
1693
1694<reference anchor="Part2">
1695  <front>
1696    <title abbrev="HTTP/1.1">HTTP/1.1, part 2: Message Semantics</title>
1697    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1698      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1699      <address><email>fielding@gbiv.com</email></address>
1700    </author>
1701    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1702      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1703      <address><email>jg@freedesktop.org</email></address>
1704    </author>
1705    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1706      <organization abbrev="HP">Hewlett-Packard Company</organization>
1707      <address><email>JeffMogul@acm.org</email></address>
1708    </author>
1709    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1710      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1711      <address><email>henrikn@microsoft.com</email></address>
1712    </author>
1713    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1714      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1715      <address><email>LMM@acm.org</email></address>
1716    </author>
1717    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1718      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1719      <address><email>paulle@microsoft.com</email></address>
1720    </author>
1721    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1722      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1723      <address><email>timbl@w3.org</email></address>
1724    </author>
1725    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1726      <organization abbrev="W3C">World Wide Web Consortium</organization>
1727      <address><email>ylafon@w3.org</email></address>
1728    </author>
1729    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1730      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1731      <address><email>julian.reschke@greenbytes.de</email></address>
1732    </author>
1733    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1734  </front>
1735  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1736  <x:source href="p2-semantics.xml" basename="p2-semantics"/>
1737</reference>
1738
1739<reference anchor="Part4">
1740  <front>
1741    <title abbrev="HTTP/1.1">HTTP/1.1, part 4: Conditional Requests</title>
1742    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1743      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1744      <address><email>fielding@gbiv.com</email></address>
1745    </author>
1746    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1747      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1748      <address><email>jg@freedesktop.org</email></address>
1749    </author>
1750    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1751      <organization abbrev="HP">Hewlett-Packard Company</organization>
1752      <address><email>JeffMogul@acm.org</email></address>
1753    </author>
1754    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1755      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1756      <address><email>henrikn@microsoft.com</email></address>
1757    </author>
1758    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1759      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1760      <address><email>LMM@acm.org</email></address>
1761    </author>
1762    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1763      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1764      <address><email>paulle@microsoft.com</email></address>
1765    </author>
1766    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1767      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1768      <address><email>timbl@w3.org</email></address>
1769    </author>
1770    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1771      <organization abbrev="W3C">World Wide Web Consortium</organization>
1772      <address><email>ylafon@w3.org</email></address>
1773    </author>
1774    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1775      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1776      <address><email>julian.reschke@greenbytes.de</email></address>
1777    </author>
1778    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1779  </front>
1780  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1781  <x:source href="p4-conditional.xml" basename="p4-conditional"/>
1782</reference>
1783
1784<reference anchor="Part5">
1785  <front>
1786    <title abbrev="HTTP/1.1">HTTP/1.1, part 5: Range Requests and Partial Responses</title>
1787    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1788      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1789      <address><email>fielding@gbiv.com</email></address>
1790    </author>
1791    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1792      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1793      <address><email>jg@freedesktop.org</email></address>
1794    </author>
1795    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1796      <organization abbrev="HP">Hewlett-Packard Company</organization>
1797      <address><email>JeffMogul@acm.org</email></address>
1798    </author>
1799    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1800      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1801      <address><email>henrikn@microsoft.com</email></address>
1802    </author>
1803    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1804      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1805      <address><email>LMM@acm.org</email></address>
1806    </author>
1807    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1808      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1809      <address><email>paulle@microsoft.com</email></address>
1810    </author>
1811    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1812      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1813      <address><email>timbl@w3.org</email></address>
1814    </author>
1815    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1816      <organization abbrev="W3C">World Wide Web Consortium</organization>
1817      <address><email>ylafon@w3.org</email></address>
1818    </author>
1819    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1820      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1821      <address><email>julian.reschke@greenbytes.de</email></address>
1822    </author>
1823    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1824  </front>
1825  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p5-range-&ID-VERSION;"/>
1826  <x:source href="p5-range.xml" basename="p5-range"/>
1827</reference>
1828
1829<reference anchor="Part6">
1830  <front>
1831    <title abbrev="HTTP/1.1">HTTP/1.1, part 6: Caching</title>
1832    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1833      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1834      <address><email>fielding@gbiv.com</email></address>
1835    </author>
1836    <author initials="J." surname="Gettys" fullname="Jim Gettys">
1837      <organization abbrev="Alcatel-Lucent">Alcatel-Lucent Bell Labs</organization>
1838      <address><email>jg@freedesktop.org</email></address>
1839    </author>
1840    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
1841      <organization abbrev="HP">Hewlett-Packard Company</organization>
1842      <address><email>JeffMogul@acm.org</email></address>
1843    </author>
1844    <author initials="H." surname="Frystyk" fullname="Henrik Frystyk Nielsen">
1845      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1846      <address><email>henrikn@microsoft.com</email></address>
1847    </author>
1848    <author initials="L." surname="Masinter" fullname="Larry Masinter">
1849      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1850      <address><email>LMM@acm.org</email></address>
1851    </author>
1852    <author initials="P." surname="Leach" fullname="Paul J. Leach">
1853      <organization abbrev="Microsoft">Microsoft Corporation</organization>
1854      <address><email>paulle@microsoft.com</email></address>
1855    </author>
1856    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
1857      <organization abbrev="W3C/MIT">World Wide Web Consortium</organization>
1858      <address><email>timbl@w3.org</email></address>
1859    </author>
1860    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1861      <organization abbrev="W3C">World Wide Web Consortium</organization>
1862      <address><email>ylafon@w3.org</email></address>
1863    </author>
1864    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1865      <organization>Rackspace</organization>
1866      <address><email>mnot@mnot.net</email></address>
1867    </author>
1868    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1869      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1870      <address><email>julian.reschke@greenbytes.de</email></address>
1871    </author>
1872    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1873  </front>
1874  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1875  <x:source href="p6-cache.xml" basename="p6-cache"/>
1876</reference>
1877
1878<reference anchor="RFC1950">
1879  <front>
1880    <title>ZLIB Compressed Data Format Specification version 3.3</title>
1881    <author initials="L.P." surname="Deutsch" fullname="L. Peter Deutsch">
1882      <organization>Aladdin Enterprises</organization>
1883      <address><email>ghost@aladdin.com</email></address>
1884    </author>
1885    <author initials="J-L." surname="Gailly" fullname="Jean-Loup Gailly"/>
1886    <date month="May" year="1996"/>
1887  </front>
1888  <seriesInfo name="RFC" value="1950"/>
1889  <!--<annotation>
1890    RFC 1950 is an Informational RFC, thus it might be less stable than
1891    this specification. On the other hand, this downward reference was
1892    present since the publication of <xref target="RFC2068" x:fmt="none">RFC 2068</xref> in 1997,
1893    therefore it is unlikely to cause problems in practice. See also
1894    <xref target="BCP97"/>.
1895  </annotation>-->
1896</reference>
1897
1898<reference anchor="RFC1951">
1899  <front>
1900    <title>DEFLATE Compressed Data Format Specification version 1.3</title>
1901    <author initials="P." surname="Deutsch" fullname="L. Peter Deutsch">
1902      <organization>Aladdin Enterprises</organization>
1903      <address><email>ghost@aladdin.com</email></address>
1904    </author>
1905    <date month="May" year="1996"/>
1906  </front>
1907  <seriesInfo name="RFC" value="1951"/>
1908  <!--<annotation>
1909    RFC 1951 is an Informational RFC, thus it might be less stable than
1910    this specification. On the other hand, this downward reference was
1911    present since the publication of <xref target="RFC2068" x:fmt="none">RFC 2068</xref> in 1997,
1912    therefore it is unlikely to cause problems in practice. See also
1913    <xref target="BCP97"/>.
1914  </annotation>-->
1915</reference>
1916
1917<reference anchor="RFC1952">
1918  <front>
1919    <title>GZIP file format specification version 4.3</title>
1920    <author initials="P." surname="Deutsch" fullname="L. Peter Deutsch">
1921      <organization>Aladdin Enterprises</organization>
1922      <address><email>ghost@aladdin.com</email></address>
1923    </author>
1924    <author initials="J-L." surname="Gailly" fullname="Jean-Loup Gailly">
1925      <address><email>gzip@prep.ai.mit.edu</email></address>
1926    </author>
1927    <author initials="M." surname="Adler" fullname="Mark Adler">
1928      <address><email>madler@alumni.caltech.edu</email></address>
1929    </author>
1930    <author initials="L.P." surname="Deutsch" fullname="L. Peter Deutsch">
1931      <address><email>ghost@aladdin.com</email></address>
1932    </author>
1933    <author initials="G." surname="Randers-Pehrson" fullname="Glenn Randers-Pehrson">
1934      <address><email>randeg@alumni.rpi.edu</email></address>
1935    </author>
1936    <date month="May" year="1996"/>
1937  </front>
1938  <seriesInfo name="RFC" value="1952"/>
1939  <!--<annotation>
1940    RFC 1952 is an Informational RFC, thus it might be less stable than
1941    this specification. On the other hand, this downward reference was
1942    present since the publication of <xref target="RFC2068" x:fmt="none">RFC 2068</xref> in 1997,
1943    therefore it is unlikely to cause problems in practice. See also
1944    <xref target="BCP97"/>.
1945  </annotation>-->
1946</reference>
1947
1948<reference anchor="RFC2045">
1949  <front>
1950    <title abbrev="Internet Message Bodies">Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</title>
1951    <author initials="N." surname="Freed" fullname="Ned Freed">
1952      <organization>Innosoft International, Inc.</organization>
1953      <address><email>ned@innosoft.com</email></address>
1954    </author>
1955    <author initials="N.S." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1956      <organization>First Virtual Holdings</organization>
1957      <address><email>nsb@nsb.fv.com</email></address>
1958    </author>
1959    <date month="November" year="1996"/>
1960  </front>
1961  <seriesInfo name="RFC" value="2045"/>
1962</reference>
1963
1964<reference anchor="RFC2046">
1965  <front>
1966    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1967    <author initials="N." surname="Freed" fullname="Ned Freed">
1968      <organization>Innosoft International, Inc.</organization>
1969      <address><email>ned@innosoft.com</email></address>
1970    </author>
1971    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1972      <organization>First Virtual Holdings</organization>
1973      <address><email>nsb@nsb.fv.com</email></address>
1974    </author>
1975    <date month="November" year="1996"/>
1976  </front>
1977  <seriesInfo name="RFC" value="2046"/>
1978</reference>
1979
1980<reference anchor="RFC2119">
1981  <front>
1982    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1983    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1984      <organization>Harvard University</organization>
1985      <address><email>sob@harvard.edu</email></address>
1986    </author>
1987    <date month="March" year="1997"/>
1988  </front>
1989  <seriesInfo name="BCP" value="14"/>
1990  <seriesInfo name="RFC" value="2119"/>
1991</reference>
1992
1993<reference anchor='RFC4647'>
1994  <front>
1995    <title>Matching of Language Tags</title>
1996    <author initials='A.' surname='Phillips' fullname='Addison Phillips' role="editor">
1997      <organization>Yahoo! Inc.</organization>
1998      <address><email>addison@inter-locale.com</email></address>
1999    </author>
2000    <author initials='M.' surname='Davis' fullname='Mark Davis' role="editor">
2001      <organization>Google</organization>
2002      <address><email>mark.davis@macchiato.com</email></address>
2003    </author>
2004    <date year='2006' month='September' />
2005  </front>
2006  <seriesInfo name='BCP' value='47' />
2007  <seriesInfo name='RFC' value='4647' />
2008</reference>
2009
2010<reference anchor="RFC5234">
2011  <front>
2012    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
2013    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
2014      <organization>Brandenburg InternetWorking</organization>
2015      <address>
2016        <email>dcrocker@bbiw.net</email>
2017      </address> 
2018    </author>
2019    <author initials="P." surname="Overell" fullname="Paul Overell">
2020      <organization>THUS plc.</organization>
2021      <address>
2022        <email>paul.overell@thus.net</email>
2023      </address>
2024    </author>
2025    <date month="January" year="2008"/>
2026  </front>
2027  <seriesInfo name="STD" value="68"/>
2028  <seriesInfo name="RFC" value="5234"/>
2029</reference>
2030
2031<reference anchor='RFC5646'>
2032  <front>
2033    <title>Tags for Identifying Languages</title>
2034    <author initials='A.' surname='Phillips' fullname='Addison Phillips' role='editor'>
2035      <organization>Lab126</organization>
2036      <address><email>addison@inter-locale.com</email></address>
2037    </author>
2038    <author initials='M.' surname='Davis' fullname='Mark Davis' role='editor'>
2039      <organization>Google</organization>
2040      <address><email>mark.davis@google.com</email></address>
2041    </author>
2042    <date month='September' year='2009' />
2043  </front>
2044  <seriesInfo name='BCP' value='47' />
2045  <seriesInfo name='RFC' value='5646' />
2046</reference>
2047
2048</references>
2049
2050<references title="Informative References">
2051
2052<reference anchor="RFC1945">
2053  <front>
2054    <title abbrev="HTTP/1.0">Hypertext Transfer Protocol -- HTTP/1.0</title>
2055    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
2056      <organization>MIT, Laboratory for Computer Science</organization>
2057      <address><email>timbl@w3.org</email></address>
2058    </author>
2059    <author initials="R.T." surname="Fielding" fullname="Roy T. Fielding">
2060      <organization>University of California, Irvine, Department of Information and Computer Science</organization>
2061      <address><email>fielding@ics.uci.edu</email></address>
2062    </author>
2063    <author initials="H.F." surname="Nielsen" fullname="Henrik Frystyk Nielsen">
2064      <organization>W3 Consortium, MIT Laboratory for Computer Science</organization>
2065      <address><email>frystyk@w3.org</email></address>
2066    </author>
2067    <date month="May" year="1996"/>
2068  </front>
2069  <seriesInfo name="RFC" value="1945"/>
2070</reference>
2071
2072<reference anchor="RFC2049">
2073  <front>
2074    <title abbrev="MIME Conformance">Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples</title>
2075    <author initials="N." surname="Freed" fullname="Ned Freed">
2076      <organization>Innosoft International, Inc.</organization>
2077      <address><email>ned@innosoft.com</email></address>
2078    </author>
2079    <author initials="N.S." surname="Borenstein" fullname="Nathaniel S. Borenstein">
2080      <organization>First Virtual Holdings</organization>
2081      <address><email>nsb@nsb.fv.com</email></address>
2082    </author>
2083    <date month="November" year="1996"/>
2084  </front>
2085  <seriesInfo name="RFC" value="2049"/>
2086</reference>
2087
2088<reference anchor="RFC2068">
2089  <front>
2090    <title abbrev="HTTP/1.1">Hypertext Transfer Protocol -- HTTP/1.1</title>
2091    <author initials="R." surname="Fielding" fullname="Roy T. Fielding">
2092      <organization>University of California, Irvine, Department of Information and Computer Science</organization>
2093      <address><email>fielding@ics.uci.edu</email></address>
2094    </author>
2095    <author initials="J." surname="Gettys" fullname="Jim Gettys">
2096      <organization>MIT Laboratory for Computer Science</organization>
2097      <address><email>jg@w3.org</email></address>
2098    </author>
2099    <author initials="J." surname="Mogul" fullname="Jeffrey C. Mogul">
2100      <organization>Digital Equipment Corporation, Western Research Laboratory</organization>
2101      <address><email>mogul@wrl.dec.com</email></address>
2102    </author>
2103    <author initials="H." surname="Nielsen" fullname="Henrik Frystyk Nielsen">
2104      <organization>MIT Laboratory for Computer Science</organization>
2105      <address><email>frystyk@w3.org</email></address>
2106    </author>
2107    <author initials="T." surname="Berners-Lee" fullname="Tim Berners-Lee">
2108      <organization>MIT Laboratory for Computer Science</organization>
2109      <address><email>timbl@w3.org</email></address>
2110    </author>
2111    <date month="January" year="1997"/>
2112  </front>
2113  <seriesInfo name="RFC" value="2068"/>
2114</reference>
2115
2116<reference anchor="RFC2076">
2117  <front>
2118    <title abbrev="Internet Message Headers">Common Internet Message Headers</title>
2119    <author initials="J." surname="Palme" fullname="Jacob Palme">
2120      <organization>Stockholm University/KTH</organization>
2121      <address><email>jpalme@dsv.su.se</email></address>
2122    </author>
2123    <date month="February" year="1997"/>
2124  </front>
2125  <seriesInfo name="RFC" value="2076"/>
2126</reference>
2127
2128<reference anchor="RFC2277">
2129  <front>
2130    <title abbrev="Charset Policy">IETF Policy on Character Sets and Languages</title>
2131    <author initials="H.T." surname="Alvestrand" fullname="Harald Tveit Alvestrand">
2132      <organization>UNINETT</organization>
2133      <address><email>Harald.T.Alvestrand@uninett.no</email></address>
2134    </author>
2135    <date month="January" year="1998"/>
2136  </front>
2137  <seriesInfo name="BCP" value="18"/>
2138  <seriesInfo name="RFC" value="2277"/>
2139</reference>
2140
2141<reference anchor='RFC2295'>
2142  <front>
2143    <title abbrev='HTTP Content Negotiation'>Transparent Content Negotiation in HTTP</title>
2144    <author initials='K.' surname='Holtman' fullname='Koen Holtman'>
2145      <organization>Technische Universiteit Eindhoven</organization>
2146      <address>
2147        <email>koen@win.tue.nl</email>
2148      </address>
2149    </author>
2150    <author initials='A.H.' surname='Mutz' fullname='Andrew H. Mutz'>
2151      <organization>Hewlett-Packard Company</organization>
2152      <address>
2153        <email>mutz@hpl.hp.com</email>
2154      </address>
2155    </author>
2156    <date year='1998' month='March'/>
2157  </front>
2158  <seriesInfo name='RFC' value='2295'/>
2159</reference>
2160
2161<reference anchor="RFC2388">
2162  <front>
2163    <title abbrev="multipart/form-data">Returning Values from Forms:  multipart/form-data</title>
2164    <author initials="L." surname="Masinter" fullname="Larry Masinter">
2165      <organization>Xerox Palo Alto Research Center</organization>
2166      <address><email>masinter@parc.xerox.com</email></address>
2167    </author>
2168    <date year="1998" month="August"/>
2169  </front>
2170  <seriesInfo name="RFC" value="2388"/>
2171</reference>
2172
2173<reference anchor="RFC2557">
2174  <front>
2175    <title abbrev="MIME Encapsulation of Aggregate Documents">MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)</title>
2176    <author initials="F." surname="Palme" fullname="Jacob Palme">
2177      <organization>Stockholm University and KTH</organization>
2178      <address><email>jpalme@dsv.su.se</email></address>
2179    </author>
2180    <author initials="A." surname="Hopmann" fullname="Alex Hopmann">
2181      <organization>Microsoft Corporation</organization>
2182      <address><email>alexhop@microsoft.com</email></address>
2183    </author>
2184    <author initials="N." surname="Shelness" fullname="Nick Shelness">
2185      <organization>Lotus Development Corporation</organization>
2186      <address><email>Shelness@lotus.com</email></address>
2187    </author>
2188    <author initials="E." surname="Stefferud" fullname="Einar Stefferud">
2189      <address><email>stef@nma.com</email></address>
2190    </author>
2191    <date year="1999" month="March"/>
2192  </front>
2193  <seriesInfo name="RFC" value="2557"/>
2194</reference>
2195
2196<reference anchor="RFC2616">
2197  <front>
2198    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
2199    <author initials="R." surname="Fielding" fullname="R. Fielding">
2200      <organization>University of California, Irvine</organization>
2201      <address><email>fielding@ics.uci.edu</email></address>
2202    </author>
2203    <author initials="J." surname="Gettys" fullname="J. Gettys">
2204      <organization>W3C</organization>
2205      <address><email>jg@w3.org</email></address>
2206    </author>
2207    <author initials="J." surname="Mogul" fullname="J. Mogul">
2208      <organization>Compaq Computer Corporation</organization>
2209      <address><email>mogul@wrl.dec.com</email></address>
2210    </author>
2211    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
2212      <organization>MIT Laboratory for Computer Science</organization>
2213      <address><email>frystyk@w3.org</email></address>
2214    </author>
2215    <author initials="L." surname="Masinter" fullname="L. Masinter">
2216      <organization>Xerox Corporation</organization>
2217      <address><email>masinter@parc.xerox.com</email></address>
2218    </author>
2219    <author initials="P." surname="Leach" fullname="P. Leach">
2220      <organization>Microsoft Corporation</organization>
2221      <address><email>paulle@microsoft.com</email></address>
2222    </author>
2223    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
2224      <organization>W3C</organization>
2225      <address><email>timbl@w3.org</email></address>
2226    </author>
2227    <date month="June" year="1999"/>
2228  </front>
2229  <seriesInfo name="RFC" value="2616"/>
2230</reference>
2231
2232<reference anchor="RFC3629">
2233  <front>
2234    <title>UTF-8, a transformation format of ISO 10646</title>
2235    <author initials="F." surname="Yergeau" fullname="F. Yergeau">
2236      <organization>Alis Technologies</organization>
2237      <address><email>fyergeau@alis.com</email></address>
2238    </author>
2239    <date month="November" year="2003"/>
2240  </front>
2241  <seriesInfo name="STD" value="63"/>
2242  <seriesInfo name="RFC" value="3629"/>
2243</reference>
2244
2245<reference anchor='RFC3864'>
2246  <front>
2247    <title>Registration Procedures for Message Header Fields</title>
2248    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
2249      <organization>Nine by Nine</organization>
2250      <address><email>GK-IETF@ninebynine.org</email></address>
2251    </author>
2252    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
2253      <organization>BEA Systems</organization>
2254      <address><email>mnot@pobox.com</email></address>
2255    </author>
2256    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
2257      <organization>HP Labs</organization>
2258      <address><email>JeffMogul@acm.org</email></address>
2259    </author>
2260    <date year='2004' month='September' />
2261  </front>
2262  <seriesInfo name='BCP' value='90' />
2263  <seriesInfo name='RFC' value='3864' />
2264</reference>
2265
2266<reference anchor="RFC4288">
2267  <front>
2268    <title>Media Type Specifications and Registration Procedures</title>
2269    <author initials="N." surname="Freed" fullname="N. Freed">
2270      <organization>Sun Microsystems</organization>
2271      <address>
2272        <email>ned.freed@mrochek.com</email>
2273      </address>
2274    </author>
2275    <author initials="J." surname="Klensin" fullname="J. Klensin">
2276      <address>
2277        <email>klensin+ietf@jck.com</email>
2278      </address>
2279    </author>
2280    <date year="2005" month="December"/>
2281  </front>
2282  <seriesInfo name="BCP" value="13"/>
2283  <seriesInfo name="RFC" value="4288"/>
2284</reference>
2285
2286<reference anchor='RFC5226'>
2287  <front>
2288    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
2289    <author initials='T.' surname='Narten' fullname='T. Narten'>
2290      <organization>IBM</organization>
2291      <address><email>narten@us.ibm.com</email></address>
2292    </author>
2293    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
2294      <organization>Google</organization>
2295      <address><email>Harald@Alvestrand.no</email></address>
2296    </author>
2297    <date year='2008' month='May' />
2298  </front>
2299  <seriesInfo name='BCP' value='26' />
2300  <seriesInfo name='RFC' value='5226' />
2301</reference>
2302
2303<reference anchor="RFC5322">
2304  <front>
2305    <title>Internet Message Format</title>
2306    <author initials="P." surname="Resnick" fullname="P. Resnick">
2307      <organization>Qualcomm Incorporated</organization>
2308    </author>
2309    <date year="2008" month="October"/>
2310  </front> 
2311  <seriesInfo name="RFC" value="5322"/>
2312</reference>
2313
2314<reference anchor="RFC6151">
2315  <front>
2316    <title>Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms</title>
2317    <author initials="S." surname="Turner" fullname="S. Turner"/>
2318    <author initials="L." surname="Chen" fullname="L. Chen"/>
2319    <date year="2011" month="March" />
2320  </front>
2321  <seriesInfo name="RFC" value="6151" />
2322</reference>
2323
2324<!--<reference anchor='BCP97'>
2325  <front>
2326    <title>Handling Normative References to Standards-Track Documents</title>
2327    <author initials='J.' surname='Klensin' fullname='J. Klensin'>
2328      <address>
2329        <email>klensin+ietf@jck.com</email>
2330      </address>
2331    </author>
2332    <author initials='S.' surname='Hartman' fullname='S. Hartman'>
2333      <organization>MIT</organization>
2334      <address>
2335        <email>hartmans-ietf@mit.edu</email>
2336      </address>
2337    </author>
2338    <date year='2007' month='June' />
2339  </front>
2340  <seriesInfo name='BCP' value='97' />
2341  <seriesInfo name='RFC' value='4897' />
2342</reference>-->
2343
2344<reference anchor="RFC6266">
2345  <front>
2346    <title abbrev="Content-Disposition in HTTP">Use of the Content-Disposition Header Field
2347    in the Hypertext Transfer Protocol (HTTP)</title>
2348    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke">
2349      <organization abbrev="greenbytes">greenbytes GmbH</organization>
2350      <address>
2351        <email>julian.reschke@greenbytes.de</email>
2352      </address>
2353    </author>
2354    <date month="June" year="2011"/>
2355  </front>
2356  <seriesInfo name='RFC' value='6266' />
2357</reference>
2358
2359</references>
2360
2361<section title="Differences between HTTP and MIME" anchor="differences.between.http.and.mime">
2362<t>
2363   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
2364   allow a message-body to be transmitted in an open variety of
2365   representations and with extensible mechanisms. However, RFC 2045
2366   discusses mail, and HTTP has a few features that are different from
2367   those described in MIME. These differences were carefully chosen
2368   to optimize performance over binary connections, to allow greater
2369   freedom in the use of new media types, to make date comparisons
2370   easier, and to acknowledge the practice of some early HTTP servers
2371   and clients.
2372</t>
2373<t>
2374   This appendix describes specific areas where HTTP differs from MIME.
2375   Proxies and gateways to strict MIME environments &SHOULD; be
2376   aware of these differences and provide the appropriate conversions
2377   where necessary. Proxies and gateways from MIME environments to HTTP
2378   also need to be aware of the differences because some conversions
2379   might be required.
2380</t>
2381
2382<section title="MIME-Version" anchor="mime-version">
2383  <iref primary="true" item="MIME-Version header field" x:for-anchor=""/>
2384  <iref primary="true" item="Header Fields" subitem="MIME-Version" x:for-anchor=""/>
2385  <x:anchor-alias value="MIME-Version"/>
2386<t>
2387   HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages &MAY;
2388   include a single MIME-Version header field to indicate what
2389   version of the MIME protocol was used to construct the message. Use
2390   of the MIME-Version header field indicates that the message is in
2391   full compliance with the MIME protocol (as defined in <xref target="RFC2045"/>).
2392   Proxies/gateways are responsible for ensuring full compliance (where
2393   possible) when exporting HTTP messages to strict MIME environments.
2394</t>
2395<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="MIME-Version"/>
2396  <x:ref>MIME-Version</x:ref> = 1*<x:ref>DIGIT</x:ref> "." 1*<x:ref>DIGIT</x:ref>
2397</artwork></figure>
2398<t>
2399   MIME version "1.0" is the default for use in HTTP/1.1. However,
2400   HTTP/1.1 message parsing and semantics are defined by this document
2401   and not the MIME specification.
2402</t>
2403</section>
2404
2405<section title="Conversion to Canonical Form" anchor="conversion.to.canonical.form">
2406<t>
2407   MIME requires that an Internet mail body-part be converted to
2408   canonical form prior to being transferred, as described in <xref target="RFC2049" x:fmt="of" x:sec="4"/>.
2409   <xref target="canonicalization.and.text.defaults"/> of this document describes the forms
2410   allowed for subtypes of the "text" media type when transmitted over
2411   HTTP. <xref target="RFC2046"/> requires that content with a type of "text" represent
2412   line breaks as CRLF and forbids the use of CR or LF outside of line
2413   break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a
2414   line break within text content when a message is transmitted over
2415   HTTP.
2416</t>
2417<t>
2418   Where it is possible, a proxy or gateway from HTTP to a strict MIME
2419   environment &SHOULD; translate all line breaks within the text media
2420   types described in <xref target="canonicalization.and.text.defaults"/>
2421   of this document to the RFC 2049
2422   canonical form of CRLF. Note, however, that this might be complicated
2423   by the presence of a Content-Encoding and by the fact that HTTP
2424   allows the use of some character encodings which do not use octets 13 and
2425   10 to represent CR and LF, respectively, as is the case for some multi-byte
2426   character encodings.
2427</t>
2428<t>
2429   Conversion will break any cryptographic
2430   checksums applied to the original content unless the original content
2431   is already in canonical form. Therefore, the canonical form is
2432   recommended for any content that uses such checksums in HTTP.
2433</t>
2434</section>
2435
2436
2437<section title="Conversion of Date Formats" anchor="conversion.of.date.formats">
2438<t>
2439   HTTP/1.1 uses a restricted set of date formats (&http-date;) to
2440   simplify the process of date comparison. Proxies and gateways from
2441   other protocols &SHOULD; ensure that any Date header field present in a
2442   message conforms to one of the HTTP/1.1 formats and rewrite the date
2443   if necessary.
2444</t>
2445</section>
2446
2447<section title="Introduction of Content-Encoding" anchor="introduction.of.content-encoding">
2448<t>
2449   MIME does not include any concept equivalent to HTTP/1.1's
2450   Content-Encoding header field. Since this acts as a modifier on the
2451   media type, proxies and gateways from HTTP to MIME-compliant
2452   protocols &MUST; either change the value of the Content-Type header
2453   field or decode the representation before forwarding the message. (Some
2454   experimental applications of Content-Type for Internet mail have used
2455   a media-type parameter of ";conversions=&lt;content-coding&gt;" to perform
2456   a function equivalent to Content-Encoding. However, this parameter is
2457   not part of the MIME standards).
2458</t>
2459</section>
2460
2461<section title="No Content-Transfer-Encoding" anchor="no.content-transfer-encoding">
2462<t>
2463   HTTP does not use the Content-Transfer-Encoding field of MIME.
2464   Proxies and gateways from MIME-compliant protocols to HTTP &MUST;
2465   remove any Content-Transfer-Encoding
2466   prior to delivering the response message to an HTTP client.
2467</t>
2468<t>
2469   Proxies and gateways from HTTP to MIME-compliant protocols are
2470   responsible for ensuring that the message is in the correct format
2471   and encoding for safe transport on that protocol, where "safe
2472   transport" is defined by the limitations of the protocol being used.
2473   Such a proxy or gateway &SHOULD; label the data with an appropriate
2474   Content-Transfer-Encoding if doing so will improve the likelihood of
2475   safe transport over the destination protocol.
2476</t>
2477</section>
2478
2479<section title="Introduction of Transfer-Encoding" anchor="introduction.of.transfer-encoding">
2480<t>
2481   HTTP/1.1 introduces the Transfer-Encoding header field (&header-transfer-encoding;).
2482   Proxies/gateways &MUST; remove any transfer-coding prior to
2483   forwarding a message via a MIME-compliant protocol.
2484</t>
2485</section>
2486
2487<section title="MHTML and Line Length Limitations" anchor="mhtml.line.length">
2488<t>
2489   HTTP implementations which share code with MHTML <xref target="RFC2557"/> implementations
2490   need to be aware of MIME line length limitations. Since HTTP does not
2491   have this limitation, HTTP does not fold long lines. MHTML messages
2492   being transported by HTTP follow all conventions of MHTML, including
2493   line length limitations and folding, canonicalization, etc., since
2494   HTTP transports all message-bodies as payload (see <xref target="multipart.types"/>) and
2495   does not interpret the content or any MIME header lines that might be
2496   contained therein.
2497</t>
2498</section>
2499</section>
2500
2501<section title="Additional Features" anchor="additional.features">
2502<t>
2503   <xref target="RFC1945"/> and <xref target="RFC2068"/> document protocol elements used by some
2504   existing HTTP implementations, but not consistently and correctly
2505   across most HTTP/1.1 applications. Implementors are advised to be
2506   aware of these features, but cannot rely upon their presence in, or
2507   interoperability with, other HTTP/1.1 applications. Some of these
2508   describe proposed experimental features, and some describe features
2509   that experimental deployment found lacking that are now addressed in
2510   the base HTTP/1.1 specification.
2511</t>
2512<t>
2513   A number of other header fields, such as Content-Disposition and Title,
2514   from SMTP and MIME are also often implemented (see <xref target="RFC6266"/>
2515   and <xref target="RFC2076"/>).
2516</t>
2517</section>
2518
2519<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
2520<t>
2521  Clarify contexts that charset is used in.
2522  (<xref target="character.sets"/>)
2523</t>
2524<t>
2525  Remove the default character encoding for text media types; the default
2526  now is whatever the media type definition says.
2527  (<xref target="canonicalization.and.text.defaults"/>)
2528</t>
2529<t>
2530  Change ABNF productions for header fields to only define the field value.
2531  (<xref target="header.field.definitions"/>)
2532</t>
2533<t>
2534  Remove definition of Content-MD5 header field because it was inconsistently
2535  implemented with respect to partial responses, and also because of known
2536  deficiencies in the hash algorithm itself (see <xref target="RFC6151"/> for details).
2537  (<xref target="header.field.definitions"/>)
2538</t>
2539<t>
2540  Remove ISO-8859-1 special-casing in Accept-Charset.
2541  (<xref target="header.accept-charset"/>)
2542</t>
2543<t>
2544  Remove base URI setting semantics for Content-Location due to poor
2545  implementation support, which was caused by too many broken servers emitting
2546  bogus Content-Location header fields, and also the potentially undesirable effect
2547  of potentially breaking relative links in content-negotiated resources.
2548  (<xref target="header.content-location"/>)
2549</t>
2550<t>
2551  Remove discussion of Content-Disposition header field, it is now defined
2552  by <xref target="RFC6266"/>.
2553  (<xref target="additional.features"/>)
2554</t>
2555<t>
2556  Remove reference to non-existant identity transfer-coding value tokens.
2557  (<xref target="no.content-transfer-encoding"/>)
2558</t>
2559</section>
2560
2561<?BEGININC p3-payload.abnf-appendix ?>
2562<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
2563<figure>
2564<artwork type="abnf" name="p3-payload.parsed-abnf">
2565<x:ref>Accept</x:ref> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [
2566 OWS media-range [ accept-params ] ] ) ]
2567<x:ref>Accept-Charset</x:ref> = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q="
2568 qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q="
2569 qvalue ] ] )
2570<x:ref>Accept-Encoding</x:ref> = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) )
2571 *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ]
2572<x:ref>Accept-Language</x:ref> = *( "," OWS ) language-range [ OWS ";" OWS "q="
2573 qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ]
2574 ] )
2575
2576<x:ref>Content-Encoding</x:ref> = *( "," OWS ) content-coding *( OWS "," [ OWS
2577 content-coding ] )
2578<x:ref>Content-Language</x:ref> = *( "," OWS ) language-tag *( OWS "," [ OWS
2579 language-tag ] )
2580<x:ref>Content-Location</x:ref> = absolute-URI / partial-URI
2581<x:ref>Content-Type</x:ref> = media-type
2582
2583<x:ref>MIME-Version</x:ref> = 1*DIGIT "." 1*DIGIT
2584
2585<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 1.2.2&gt;
2586
2587<x:ref>absolute-URI</x:ref> = &lt;absolute-URI, defined in [Part1], Section 2.7&gt;
2588<x:ref>accept-ext</x:ref> = OWS ";" OWS token [ "=" word ]
2589<x:ref>accept-params</x:ref> = OWS ";" OWS "q=" qvalue *accept-ext
2590<x:ref>attribute</x:ref> = token
2591
2592<x:ref>charset</x:ref> = token
2593<x:ref>codings</x:ref> = content-coding / "identity" / "*"
2594<x:ref>content-coding</x:ref> = token
2595
2596<x:ref>language-range</x:ref> = &lt;language-range, defined in [RFC4647], Section 2.1&gt;
2597<x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in [RFC5646], Section 2.1&gt;
2598
2599<x:ref>media-range</x:ref> = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS
2600 ";" OWS parameter )
2601<x:ref>media-type</x:ref> = type "/" subtype *( OWS ";" OWS parameter )
2602
2603<x:ref>parameter</x:ref> = attribute "=" value
2604<x:ref>partial-URI</x:ref> = &lt;partial-URI, defined in [Part1], Section 2.7&gt;
2605
2606<x:ref>qvalue</x:ref> = &lt;qvalue, defined in [Part1], Section 5.3&gt;
2607
2608<x:ref>subtype</x:ref> = token
2609
2610<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.3&gt;
2611<x:ref>type</x:ref> = token
2612
2613<x:ref>value</x:ref> = word
2614
2615<x:ref>word</x:ref> = &lt;word, defined in [Part1], Section 3.2.3&gt;
2616</artwork>
2617</figure>
2618<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
2619; Accept defined but not used
2620; Accept-Charset defined but not used
2621; Accept-Encoding defined but not used
2622; Accept-Language defined but not used
2623; Content-Encoding defined but not used
2624; Content-Language defined but not used
2625; Content-Location defined but not used
2626; Content-Type defined but not used
2627; MIME-Version defined but not used
2628</artwork></figure></section>
2629<?ENDINC p3-payload.abnf-appendix ?>
2630
2631<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
2632
2633<section title="Since RFC 2616">
2634<t>
2635  Extracted relevant partitions from <xref target="RFC2616"/>.
2636</t>
2637</section>
2638
2639<section title="Since draft-ietf-httpbis-p3-payload-00">
2640<t>
2641  Closed issues:
2642  <list style="symbols"> 
2643    <t>
2644      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/8"/>:
2645      "Media Type Registrations"
2646      (<eref target="http://purl.org/NET/http-errata#media-reg"/>)
2647    </t>
2648    <t>
2649      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/14"/>:
2650      "Clarification regarding quoting of charset values"
2651      (<eref target="http://purl.org/NET/http-errata#charactersets"/>)
2652    </t>
2653    <t>
2654      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/16"/>:
2655      "Remove 'identity' token references"
2656      (<eref target="http://purl.org/NET/http-errata#identity"/>)
2657    </t>
2658    <t>
2659      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/25"/>:
2660      "Accept-Encoding BNF"
2661    </t>
2662    <t>
2663      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
2664      "Normative and Informative references"
2665    </t>
2666    <t>
2667      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/46"/>:
2668      "RFC1700 references"
2669    </t>
2670    <t>
2671      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
2672      "Updating to RFC4288"
2673    </t>
2674    <t>
2675      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/65"/>:
2676      "Informative references"
2677    </t>
2678    <t>
2679      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/66"/>:
2680      "ISO-8859-1 Reference"
2681    </t>
2682    <t>
2683      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>:
2684      "Encoding References Normative"
2685    </t>
2686    <t>
2687      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
2688      "Normative up-to-date references"
2689    </t>
2690  </list>
2691</t>
2692</section>
2693
2694<section title="Since draft-ietf-httpbis-p3-payload-01">
2695<t>
2696  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2697  <list style="symbols"> 
2698    <t>
2699      Add explicit references to BNF syntax and rules imported from other parts of the specification.
2700    </t>
2701  </list>
2702</t>
2703</section>
2704
2705<section title="Since draft-ietf-httpbis-p3-payload-02" anchor="changes.since.02">
2706<t>
2707  Closed issues:
2708  <list style="symbols"> 
2709    <t>
2710      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>:
2711      "Quoting Charsets"
2712    </t>
2713    <t>
2714      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/105"/>:
2715      "Classification for Allow header"
2716    </t>
2717    <t>
2718      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/115"/>:
2719      "missing default for qvalue in description of Accept-Encoding"
2720    </t>
2721  </list>
2722</t>
2723<t>
2724  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
2725  <list style="symbols"> 
2726    <t>
2727      Reference RFC 3984, and update header field registrations for headers defined
2728      in this document.
2729    </t>
2730  </list>
2731</t>
2732</section>
2733
2734<section title="Since draft-ietf-httpbis-p3-payload-03" anchor="changes.since.03">
2735<t>
2736  Closed issues:
2737  <list style="symbols"> 
2738    <t>
2739      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>:
2740      "Quoting Charsets"
2741    </t>
2742    <t>
2743      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/113"/>:
2744      "language tag matching (Accept-Language) vs RFC4647"
2745    </t>
2746    <t>
2747      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/121"/>:
2748      "RFC 1806 has been replaced by RFC2183"
2749    </t>
2750  </list>
2751</t>
2752<t>
2753  Other changes:
2754  <list style="symbols"> 
2755    <t>
2756      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>:
2757      "Encoding References Normative" &mdash; rephrase the annotation and reference
2758      BCP97.
2759    </t>
2760  </list>
2761</t>
2762 </section>
2763
2764<section title="Since draft-ietf-httpbis-p3-payload-04" anchor="changes.since.04">
2765<t>
2766  Closed issues:
2767  <list style="symbols"> 
2768    <t>
2769      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/132"/>:
2770      "RFC 2822 is updated by RFC 5322"
2771    </t>
2772  </list>
2773</t>
2774<t>
2775  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2776  <list style="symbols"> 
2777    <t>
2778      Use "/" instead of "|" for alternatives.
2779    </t>
2780    <t>
2781      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
2782      whitespace ("OWS") and required whitespace ("RWS").
2783    </t>
2784    <t>
2785      Rewrite ABNFs to spell out whitespace rules, factor out
2786      header field value format definitions.
2787    </t>
2788  </list>
2789</t>
2790</section>
2791
2792<section title="Since draft-ietf-httpbis-p3-payload-05" anchor="changes.since.05">
2793<t>
2794  Closed issues:
2795  <list style="symbols"> 
2796    <t>
2797      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/118"/>:
2798      "Join "Differences Between HTTP Entities and RFC 2045 Entities"?"
2799    </t>
2800  </list>
2801</t>
2802<t>
2803  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
2804  <list style="symbols"> 
2805    <t>
2806      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
2807    </t>
2808  </list>
2809</t>
2810<t>
2811  Other changes:
2812  <list style="symbols"> 
2813    <t>
2814      Move definition of quality values into Part 1.
2815    </t>
2816  </list>
2817</t>
2818</section>
2819
2820<section title="Since draft-ietf-httpbis-p3-payload-06" anchor="changes.since.06">
2821<t>
2822  Closed issues:
2823  <list style="symbols"> 
2824    <t>
2825      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>:
2826      "Content-Location isn't special"
2827    </t>
2828    <t>
2829      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2830      "Content Sniffing"
2831    </t>
2832  </list>
2833</t>
2834</section>
2835
2836<section title="Since draft-ietf-httpbis-p3-payload-07" anchor="changes.since.07">
2837<t>
2838  Closed issues:
2839  <list style="symbols"> 
2840    <t>
2841      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/13"/>:
2842      "Updated reference for language tags"
2843    </t>
2844    <t>
2845      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/110"/>:
2846      "Clarify rules for determining what entities a response carries"
2847    </t>
2848    <t>
2849      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/154"/>:
2850      "Content-Location base-setting problems"
2851    </t>
2852    <t>
2853      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2854      "Content Sniffing"
2855    </t>
2856    <t>
2857      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/188"/>:
2858      "pick IANA policy (RFC5226) for Transfer Coding / Content Coding"
2859    </t>
2860    <t>
2861      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/189"/>:
2862      "move definitions of gzip/deflate/compress to part 1"
2863    </t>
2864  </list>
2865</t>
2866<t>
2867  Partly resolved issues:
2868  <list style="symbols"> 
2869    <t>
2870      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/148"/>:
2871      "update IANA requirements wrt Transfer-Coding values" (add the
2872      IANA Considerations subsection)
2873    </t>
2874    <t>
2875      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/149"/>:
2876      "update IANA requirements wrt Content-Coding values" (add the
2877      IANA Considerations subsection)
2878    </t>
2879  </list>
2880</t>
2881</section>
2882
2883<section title="Since draft-ietf-httpbis-p3-payload-08" anchor="changes.since.08">
2884<t>
2885  Closed issues:
2886  <list style="symbols"> 
2887    <t>
2888      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/81"/>:
2889      "Content Negotiation for media types"
2890    </t>
2891    <t>
2892      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/181"/>:
2893      "Accept-Language: which RFC4647 filtering?"
2894    </t>
2895  </list>
2896</t>
2897</section>
2898
2899<section title="Since draft-ietf-httpbis-p3-payload-09" anchor="changes.since.09">
2900<t>
2901  Closed issues:
2902  <list style="symbols"> 
2903    <t>
2904      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/122"/>:
2905      "MIME-Version not listed in P1, general header fields"
2906    </t>
2907    <t>
2908      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/143"/>:
2909      "IANA registry for content/transfer encodings"
2910    </t>
2911    <t>
2912      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>:
2913      "Content Sniffing"
2914    </t>
2915    <t>
2916      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/200"/>:
2917      "use of term "word" when talking about header structure"
2918    </t>
2919  </list>
2920</t>
2921<t>
2922  Partly resolved issues:
2923  <list style="symbols"> 
2924    <t>
2925      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/196"/>:
2926      "Term for the requested resource's URI"
2927    </t>
2928  </list>
2929</t>
2930</section>
2931
2932<section title="Since draft-ietf-httpbis-p3-payload-10" anchor="changes.since.10">
2933<t>
2934  Closed issues:
2935  <list style="symbols"> 
2936    <t>
2937      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
2938      "Clarify 'Requested Variant'"
2939    </t>
2940    <t>
2941      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>:
2942      "Content-Location isn't special"
2943    </t>
2944    <t>
2945      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/90"/>:
2946      "Delimiting messages with multipart/byteranges"
2947    </t>
2948    <t>
2949      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
2950      "Clarify entity / representation / variant terminology"
2951    </t>
2952    <t>
2953      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/136"/>:
2954      "confusing req. language for Content-Location"
2955    </t>
2956    <t>
2957      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/167"/>:
2958      "Content-Location on 304 responses"
2959    </t>
2960    <t>
2961      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/183"/>:
2962      "'requested resource' in content-encoding definition"
2963    </t>
2964    <t>
2965      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
2966      "consider removing the 'changes from 2068' sections"
2967    </t>
2968  </list>
2969</t>
2970<t>
2971  Partly resolved issues:
2972  <list style="symbols"> 
2973    <t>
2974      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>:
2975      "Content-MD5 and partial responses"
2976    </t>
2977  </list>
2978</t>
2979</section>
2980
2981<section title="Since draft-ietf-httpbis-p3-payload-11" anchor="changes.since.11">
2982<t>
2983  Closed issues:
2984  <list style="symbols"> 
2985    <t>
2986      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/123"/>:
2987      "Factor out Content-Disposition"
2988    </t>
2989  </list>
2990</t>
2991</section>
2992
2993<section title="Since draft-ietf-httpbis-p3-payload-12" anchor="changes.since.12">
2994<t>
2995  Closed issues:
2996  <list style="symbols"> 
2997    <t>
2998      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
2999      "Header Classification"
3000    </t>
3001    <t>
3002      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
3003      "untangle ABNFs for header fields"
3004    </t>
3005    <t>
3006      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/277"/>:
3007      "potentially misleading MAY in media-type def"
3008    </t>
3009  </list>
3010</t>
3011</section>
3012
3013<section title="Since draft-ietf-httpbis-p3-payload-13" anchor="changes.since.13">
3014<t>
3015  Closed issues:
3016  <list style="symbols"> 
3017    <t>
3018      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/20"/>:
3019      "Default charsets for text media types"
3020    </t>
3021    <t>
3022      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>:
3023      "Content-MD5 and partial responses"
3024    </t>
3025    <t>
3026      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
3027      "untangle ABNFs for header fields"
3028    </t>
3029    <t>
3030      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/281"/>:
3031      "confusing undefined parameter in media range example"
3032    </t>
3033  </list>
3034</t>
3035</section>
3036
3037<section title="Since draft-ietf-httpbis-p3-payload-14" anchor="changes.since.14">
3038<t>
3039  None.
3040</t>
3041</section>
3042
3043<section title="Since draft-ietf-httpbis-p3-payload-15" anchor="changes.since.15">
3044<t>
3045  Closed issues:
3046  <list style="symbols"> 
3047    <t>
3048      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/285"/>:
3049      "Strength of requirements on Accept re: 406"
3050    </t>
3051  </list>
3052</t>
3053</section>
3054
3055<section title="Since draft-ietf-httpbis-p3-payload-16" anchor="changes.since.16">
3056<t>
3057  Closed issues:
3058  <list style="symbols"> 
3059    <t>
3060      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/186"/>:
3061      "Document HTTP's error-handling philosophy"
3062    </t>
3063  </list>
3064</t>
3065</section>
3066
3067<section title="Since draft-ietf-httpbis-p3-payload-17" anchor="changes.since.17">
3068<t>
3069  Closed issues:
3070  <list style="symbols"> 
3071    <t>
3072      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/323"/>:
3073      "intended maturity level vs normative references"
3074    </t>
3075  </list>
3076</t>
3077</section>
3078
3079</section>
3080
3081</back>
3082</rfc>
Note: See TracBrowser for help on using the repository browser.