source: draft-ietf-httpbis/latest/p5-range.xml @ 1773

Last change on this file since 1773 was 1773, checked in by julian.reschke@…, 7 years ago

Remove ABNF diagnostics for known to be non-referenced productions (header field names)

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  • Property svn:mime-type set to text/xml
File size: 68.5 KB
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1<?xml version="1.0" encoding="utf-8"?>
2<?xml-stylesheet type='text/xsl' href='../myxml2rfc.xslt'?>
3<!DOCTYPE rfc [
4  <!ENTITY MAY "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MAY</bcp14>">
5  <!ENTITY MUST "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST</bcp14>">
6  <!ENTITY MUST-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>MUST NOT</bcp14>">
7  <!ENTITY OPTIONAL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>OPTIONAL</bcp14>">
8  <!ENTITY RECOMMENDED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>RECOMMENDED</bcp14>">
9  <!ENTITY REQUIRED "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>REQUIRED</bcp14>">
10  <!ENTITY SHALL "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL</bcp14>">
11  <!ENTITY SHALL-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHALL NOT</bcp14>">
12  <!ENTITY SHOULD "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD</bcp14>">
13  <!ENTITY SHOULD-NOT "<bcp14 xmlns='http://purl.org/net/xml2rfc/ext'>SHOULD NOT</bcp14>">
14  <!ENTITY ID-VERSION "latest">
15  <!ENTITY ID-MONTH "July">
16  <!ENTITY ID-YEAR "2012">
17  <!ENTITY Note "<x:h xmlns:x='http://purl.org/net/xml2rfc/ext'>Note:</x:h>">
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 abnf-extension             "<xref target='Part1' x:rel='#abnf.extension' 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 whitespace                 "<xref target='Part1' x:rel='#whitespace' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
23  <!ENTITY field-components           "<xref target='Part1' x:rel='#field.components' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
24  <!ENTITY http-date                  "<xref target='Part2' x:rel='#http.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
25  <!ENTITY messaging                  "<xref target='Part1' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
26  <!ENTITY entity-tags                "<xref target='Part4' x:rel='#header.etag' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
27  <!ENTITY weak-and-strong-validators "<xref target='Part4' x:rel='#weak.and.strong.validators' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
28  <!ENTITY lastmod-comparison         "<xref target='Part4' x:rel='#lastmod.comparison' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
29  <!ENTITY p6-heuristic               "<xref target='Part6' x:rel='#heuristic.freshness' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
30]>
31<?rfc toc="yes" ?>
32<?rfc symrefs="yes" ?>
33<?rfc sortrefs="yes" ?>
34<?rfc compact="yes"?>
35<?rfc subcompact="no" ?>
36<?rfc linkmailto="no" ?>
37<?rfc editing="no" ?>
38<?rfc comments="yes"?>
39<?rfc inline="yes"?>
40<?rfc rfcedstyle="yes"?>
41<?rfc-ext allow-markup-in-artwork="yes" ?>
42<?rfc-ext include-references-in-index="yes" ?>
43<rfc obsoletes="2616" category="std" x:maturity-level="proposed"
44     ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p5-range-&ID-VERSION;"
45     xmlns:x='http://purl.org/net/xml2rfc/ext'>
46<x:link rel="prev" basename="p4-conditional"/>
47<x:link rel="next" basename="p6-cache"/>
48<x:feedback template="mailto:ietf-http-wg@w3.org?subject={docname},%20%22{section}%22&amp;body=&lt;{ref}&gt;:"/>
49<front>
50
51  <title abbrev="HTTP/1.1, Part 5">HTTP/1.1, part 5: Range Requests and Partial Responses</title>
52
53  <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
54    <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
55    <address>
56      <postal>
57        <street>345 Park Ave</street>
58        <city>San Jose</city>
59        <region>CA</region>
60        <code>95110</code>
61        <country>USA</country>
62      </postal>
63      <email>fielding@gbiv.com</email>
64      <uri>http://roy.gbiv.com/</uri>
65    </address>
66  </author>
67
68  <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
69    <organization abbrev="W3C">World Wide Web Consortium</organization>
70    <address>
71      <postal>
72        <street>W3C / ERCIM</street>
73        <street>2004, rte des Lucioles</street>
74        <city>Sophia-Antipolis</city>
75        <region>AM</region>
76        <code>06902</code>
77        <country>France</country>
78      </postal>
79      <email>ylafon@w3.org</email>
80      <uri>http://www.raubacapeu.net/people/yves/</uri>
81    </address>
82  </author>
83
84  <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
85    <organization abbrev="greenbytes">greenbytes GmbH</organization>
86    <address>
87      <postal>
88        <street>Hafenweg 16</street>
89        <city>Muenster</city><region>NW</region><code>48155</code>
90        <country>Germany</country>
91      </postal>
92      <email>julian.reschke@greenbytes.de</email>
93      <uri>http://greenbytes.de/tech/webdav/</uri>
94    </address>
95  </author>
96
97  <date month="&ID-MONTH;" year="&ID-YEAR;"/>
98  <workgroup>HTTPbis Working Group</workgroup>
99
100<abstract>
101<t>
102   The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
103   distributed, collaborative, hypertext information systems. HTTP has been in
104   use by the World Wide Web global information initiative since 1990. This
105   document is Part 5 of the seven-part specification that defines the protocol
106   referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616.
107</t>
108<t>
109   Part 5 defines range requests and the rules for constructing and
110   combining responses to those requests.
111</t>
112</abstract>
113
114<note title="Editorial Note (To be removed by RFC Editor)">
115  <t>
116    Discussion of this draft takes place on the HTTPBIS working group
117    mailing list (ietf-http-wg@w3.org), which is archived at
118    <eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
119  </t>
120  <t>
121    The current issues list is at
122    <eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
123    documents (including fancy diffs) can be found at
124    <eref target="http://tools.ietf.org/wg/httpbis/"/>.
125  </t>
126  <t>
127    The changes in this draft are summarized in <xref target="changes.since.19"/>.
128  </t>
129</note>
130</front>
131<middle>
132<section title="Introduction" anchor="introduction">
133<t>
134   HTTP clients often encounter interrupted data transfers as a result
135   of cancelled requests or dropped connections.  When a client has stored
136   a partial representation, it is desirable to request the remainder
137   of that representation in a subsequent request rather than transfer
138   the entire representation.
139   There are also a number of Web applications that benefit from being
140   able to request only a subset of a larger representation, such as a
141   single page of a very large document or only part of an image to be
142   rendered by a device with limited local storage.
143</t>
144<t>
145   This document defines HTTP/1.1 range requests,
146   partial responses, and the multipart/byteranges media type.
147   The protocol for range requests is an &OPTIONAL; feature of HTTP,
148   designed so resources or recipients that do not implement this feature
149   can respond as if it is a normal GET request without impacting
150   interoperability.  Partial responses are indicated by a distinct status
151   code to not be mistaken for full responses by intermediate caches
152   that might not implement the feature.
153</t>
154<t>
155   Although the HTTP range request mechanism is designed to allow for
156   extensible range types, this specification only defines requests for
157   byte ranges.
158</t>
159
160<section title="Conformance and Error Handling" anchor="intro.conformance.and.error.handling">
161<t>
162   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
163   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
164   document are to be interpreted as described in <xref target="RFC2119"/>.
165</t>
166<t>
167   This specification targets conformance criteria according to the role of
168   a participant in HTTP communication.  Hence, HTTP requirements are placed
169   on senders, recipients, clients, servers, user agents, intermediaries,
170   origin servers, proxies, gateways, or caches, depending on what behavior
171   is being constrained by the requirement. See &architecture; for definitions
172   of these terms.
173</t>
174<t>
175   The verb "generate" is used instead of "send" where a requirement
176   differentiates between creating a protocol element and merely forwarding a
177   received element downstream.
178</t>
179<t>
180   An implementation is considered conformant if it complies with all of the
181   requirements associated with the roles it partakes in HTTP. Note that
182   SHOULD-level requirements are relevant here, unless one of the documented
183   exceptions is applicable.
184</t>
185<t>
186   This document also uses ABNF to define valid protocol elements
187   (<xref target="notation"/>).
188   In addition to the prose requirements placed upon them, senders &MUST-NOT;
189   generate protocol elements that do not match the grammar defined by the
190   ABNF rules for those protocol elements that are applicable to the sender's
191   role. If a received protocol element is processed, the recipient &MUST; be
192   able to parse any value that would match the ABNF rules for that protocol
193   element, excluding only those rules not applicable to the recipient's role.
194</t>
195<t>
196   Unless noted otherwise, a recipient &MAY; attempt to recover a usable
197   protocol element from an invalid construct.  HTTP does not define
198   specific error handling mechanisms except when they have a direct impact
199   on security, since different applications of the protocol require
200   different error handling strategies.  For example, a Web browser might
201   wish to transparently recover from a response where the
202   <x:ref>Location</x:ref> header field doesn't parse according to the ABNF,
203   whereas a systems control client might consider any form of error recovery
204   to be dangerous.
205</t>
206</section>
207
208<section title="Syntax Notation" anchor="notation">
209  <x:anchor-alias value="ALPHA"/>
210  <x:anchor-alias value="CHAR"/>
211  <x:anchor-alias value="CR"/>
212  <x:anchor-alias value="DIGIT"/>
213  <x:anchor-alias value="LF"/>
214  <x:anchor-alias value="OCTET"/>
215  <x:anchor-alias value="SP"/>
216  <x:anchor-alias value="VCHAR"/>
217<t>
218   This specification uses the Augmented Backus-Naur Form (ABNF) notation
219   of <xref target="RFC5234"/> with the list rule extension defined in
220   &notation;<xref target="collected.abnf"/> shows the collected ABNF
221   with the list rule expanded.
222</t>
223<t>
224  The following core rules are included by
225  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
226  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
227  DIGIT (decimal 0-9), DQUOTE (double quote),
228  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
229  OCTET (any 8-bit sequence of data), SP (space), and
230  VCHAR (any visible US-ASCII character).
231</t>
232
233<t>
234  Note that all rules derived from <x:ref>token</x:ref> are to
235  be compared case-insensitively, like <x:ref>range-unit</x:ref> and
236  <x:ref>acceptable-ranges</x:ref>.
237</t>
238
239<section title="Core Rules" anchor="core.rules">
240  <x:anchor-alias value="token"/>
241  <x:anchor-alias value="OWS"/>
242  <x:anchor-alias value="HTTP-date"/>
243<t>
244  The core rules below are defined in <xref target="Part1"/> and
245  <xref target="Part2"/>:
246</t>
247<figure><artwork type="abnf2616">
248  <x:ref>OWS</x:ref>        = &lt;OWS, defined in &whitespace;&gt;
249  <x:ref>token</x:ref>      = &lt;token, defined in &field-components;&gt;
250  <x:ref>HTTP-date</x:ref>  = &lt;HTTP-date, defined in &http-date;&gt;
251</artwork></figure>
252</section>
253
254<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
255  <x:anchor-alias value="entity-tag"/>
256<t>
257  The ABNF rules below are defined in other parts:
258</t>
259<figure><!--Part4--><artwork type="abnf2616">
260  <x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in &entity-tags;&gt;
261</artwork></figure>
262</section>
263
264</section>
265
266</section>
267
268
269<section title="Range Units" anchor="range.units">
270  <x:anchor-alias value="bytes-unit"/>
271  <x:anchor-alias value="other-range-unit"/>
272  <x:anchor-alias value="range-unit"/>
273<t>
274   HTTP/1.1 allows a client to request that only part (a range) of the
275   representation be included within the response. HTTP/1.1 uses range
276   units in the <x:ref>Range</x:ref> (<xref target="header.range"/>) and
277   <x:ref>Content-Range</x:ref> (<xref target="header.content-range"/>)
278   header fields. A representation can be broken down into subranges according
279   to various structural units.
280</t>
281<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="range-unit"/><iref primary="true" item="Grammar" subitem="bytes-unit"/><iref primary="true" item="Grammar" subitem="other-range-unit"/>
282  <x:ref>range-unit</x:ref>       = <x:ref>bytes-unit</x:ref> / <x:ref>other-range-unit</x:ref>
283  <x:ref>bytes-unit</x:ref>       = "bytes"
284  <x:ref>other-range-unit</x:ref> = <x:ref>token</x:ref>
285</artwork></figure>
286<t>
287  HTTP/1.1 has been designed to allow implementations of applications
288  that do not depend on knowledge of ranges. The only range unit defined
289  by HTTP/1.1 is "bytes". Additional specifiers can be defined as described
290  in <xref target="range.specifier.registry"/>.
291</t>
292<t>
293  If a range unit is not understood in a request, a server &MUST; ignore
294  the whole <x:ref>Range</x:ref> header field (<xref target="header.range"/>).
295  If a range unit is not understood in a response, an intermediary
296  &SHOULD; pass the response to the client; a client &MUST; fail.
297</t>
298
299<section title="Range Specifier Registry" anchor="range.specifier.registry">
300<t>
301   The HTTP Range Specifier Registry defines the name space for the range
302   specifier names.
303</t>
304<t>
305   Registrations &MUST; include the following fields:
306   <list style="symbols">
307     <t>Name</t>
308     <t>Description</t>
309     <t>Pointer to specification text</t>
310   </list>
311</t>
312<t>
313  Values to be added to this name space require IETF Review
314  (see <xref target="RFC5226" x:fmt="," x:sec="4.1"/>).
315</t>
316<t>
317   The registry itself is maintained at
318   <eref target="http://www.iana.org/assignments/http-range-specifiers"/>.
319</t>
320</section>
321
322</section>
323
324<section title="Status Code Definitions" anchor="status.code.definitions">
325<section title="206 Partial Content" anchor="status.206">
326  <iref primary="true" item="206 Partial Content (status code)" x:for-anchor=""/>
327  <iref primary="true" item="Status Codes" subitem="206 Partial Content" x:for-anchor=""/>
328  <x:anchor-alias value="206"/>
329  <x:anchor-alias value="206 (Partial Content)"/>
330<t>
331   The server has fulfilled the partial GET request for the resource.
332   The request &MUST; have included a <x:ref>Range</x:ref> header field
333   (<xref target="header.range"/>) indicating the desired range, and &MAY; have
334   included an <x:ref>If-Range</x:ref> header field
335   (<xref target="header.if-range"/>) to make the request conditional.
336</t>
337<t>
338   The response &MUST; include the following header fields:
339  <list style="symbols">
340    <t>
341        Either a <x:ref>Content-Range</x:ref> header field
342        (<xref target="header.content-range"/>) indicating
343        the range included with this response, or a multipart/byteranges
344        <x:ref>Content-Type</x:ref> including Content-Range fields for each
345        part. If a <x:ref>Content-Length</x:ref> header field is present in the
346        response, its value &MUST; match the actual number of octets
347        transmitted in the message body.
348    </t>
349    <t>
350        Date
351    </t>
352    <t>
353        <x:ref>Cache-Control</x:ref>, <x:ref>ETag</x:ref>,
354        <x:ref>Expires</x:ref>, <x:ref>Content-Location</x:ref> and/or
355        <x:ref>Vary</x:ref>, if the header field would have been sent in a
356        <x:ref>200 (OK)</x:ref> response to the same request
357    </t>
358  </list>
359</t>
360<t>
361   If a 206 is sent in response to a request with an <x:ref>If-Range</x:ref>
362   header field, it &SHOULD-NOT; include other representation header fields.
363   Otherwise, the response &MUST; include all of the representation header
364   fields that would have been returned with a <x:ref>200 (OK)</x:ref> response
365   to the same request.
366</t>
367<t>
368   Caches &MAY; use a heuristic (see &p6-heuristic;) to determine
369   freshness for 206 responses.
370</t>
371</section>
372
373<section title="416 Requested Range Not Satisfiable" anchor="status.416">
374  <iref primary="true" item="416 Requested Range Not Satisfiable (status code)" x:for-anchor=""/>
375  <iref primary="true" item="Status Codes" subitem="416 Requested Range Not Satisfiable" x:for-anchor=""/>
376  <x:anchor-alias value="416 (Requested Range Not Satisfiable)"/>
377<t>
378   A server &SHOULD; return a response with this status code if a request
379   included a <x:ref>Range</x:ref> header field (<xref target="header.range"/>),
380   and none of the ranges-specifier values in this field overlap the current
381   extent of the selected resource, and the request did not include an
382   <x:ref>If-Range</x:ref> header field (<xref target="header.if-range"/>).
383   (For byte-ranges, this means that the first-byte-pos of all of the
384   byte-range-spec values were greater than the current length of the selected
385   resource.)
386</t>
387<t>
388   When this status code is returned for a byte-range request, the
389   response &SHOULD; include a <x:ref>Content-Range</x:ref> header field
390   specifying the current length of the representation (see <xref target="header.content-range"/>).
391   This response &MUST-NOT; use the multipart/byteranges content-type. For example,
392</t>
393<figure><artwork type="message/http; msgtype=&#34;response&#34;" x:indent-with="  ">
394HTTP/1.1 416 Requested Range Not Satisfiable
395Date: Mon, 20 Jan 2012 15:41:54 GMT
396Content-Range: bytes */47022
397Content-Type: image/gif
398</artwork></figure>
399<x:note>
400  <t>
401    &Note; Clients cannot depend on servers to send a <x:ref>416 (Requested
402    Range Not Satisfiable)</x:ref> response instead of a <x:ref>200 (OK)</x:ref>
403    response for an unsatisfiable <x:ref>Range</x:ref> header field, since not
404    all servers implement this header field.
405  </t>
406</x:note>
407</section>
408</section>
409
410<section title="Responses to a Range Request">
411<section title="Response to a Single and Multiple Ranges Request">
412<t>
413   When an HTTP message includes the content of a single range (for
414   example, a response to a request for a single range, or to a request
415   for a set of ranges that overlap without any holes), this content is
416   transmitted with a <x:ref>Content-Range</x:ref> header field, and a
417   <x:ref>Content-Length</x:ref> header field showing the number of bytes
418   actually transferred. For example,
419</t>
420<figure><artwork type="message/http; msgtype=&#34;response&#34;" x:indent-with="  ">
421HTTP/1.1 206 Partial Content
422Date: Wed, 15 Nov 1995 06:25:24 GMT
423Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
424Content-Range: bytes 21010-47021/47022
425Content-Length: 26012
426Content-Type: image/gif
427</artwork></figure>
428<t>
429   When an HTTP message includes the content of multiple ranges (for
430   example, a response to a request for multiple non-overlapping
431   ranges), these are transmitted as a multipart message. The multipart
432   media type used for this purpose is "multipart/byteranges" as defined
433   in <xref target="internet.media.type.multipart.byteranges"/>.
434</t>
435<t>
436   A server &MAY; combine requested ranges when those ranges are overlapping
437   (see <xref target="overlapping.ranges"/>).
438</t>
439<t>
440   A response to a request for a single range &MUST-NOT; be sent using the
441   multipart/byteranges media type.  A response to a request for
442   multiple ranges, whose result is a single range, &MAY; be sent as a
443   multipart/byteranges media type with one part. A client that cannot
444   decode a multipart/byteranges message &MUST-NOT; ask for multiple
445   ranges in a single request.
446</t>
447<t>
448   When a client asks for multiple ranges in one request, the
449   server &SHOULD; return them in the order that they appeared in the
450   request.
451</t>
452</section>
453
454<section title="Combining Ranges" anchor="combining.byte.ranges">
455<t>
456   A response might transfer only a subrange of a representation if the
457   connection closed prematurely or if the request used one or more Range
458   specifications.  After several such transfers, a client might have
459   received several ranges of the same representation.  These ranges can only
460   be safely combined if they all have in common the same strong validator,
461   where "strong validator" is defined to be either an entity-tag that is
462   not marked as weak (&entity-tags;) or, if no entity-tag is provided, a
463   <x:ref>Last-Modified</x:ref> value that is strong in the sense defined by
464   &lastmod-comparison;.
465</t>
466<t>
467   When a client receives an incomplete <x:ref>200 (OK)</x:ref> or <x:ref>206 (Partial Content)</x:ref>
468   response and already has one or more stored responses for the same method
469   and effective request URI, all of the stored responses with the same
470   strong validator &MAY; be combined with the partial content in this new
471   response.  If none of the stored responses contain the same strong
472   validator, then this new response corresponds to a new representation
473   and &MUST-NOT; be combined with the existing stored responses.
474</t>
475<t>
476   If the new response is an incomplete <x:ref>200 (OK)</x:ref> response, then the header
477   fields of that new response are used for any combined response and replace
478   those of the matching stored responses.
479</t>
480<t>
481   If the new response is a <x:ref>206 (Partial Content)</x:ref> response and at least one
482   of the matching stored responses is a <x:ref>200 (OK)</x:ref>, then the combined response
483   header fields consist of the most recent 200 response's header fields.
484   If all of the matching stored responses are 206 responses, then the
485   stored response with the most header fields is used as the source of
486   header fields for the combined response, except that the client &MUST;
487   use other header fields provided in the new response, aside from
488   <x:ref>Content-Range</x:ref>, to replace all instances of the corresponding
489   header fields in the stored response.
490</t>
491<t>
492   The combined response message body consists of the union of partial
493   content ranges in the new response and each of the selected responses.
494   If the union consists of the entire range of the representation, then the
495   combined response &MUST; be recorded as a complete <x:ref>200 (OK)</x:ref>
496   response with a <x:ref>Content-Length</x:ref> header field that reflects the
497   complete length. Otherwise, the combined response(s) &MUST; include a
498   <x:ref>Content-Range</x:ref> header field describing the included range(s)
499   and be recorded as incomplete.  If the union consists of a discontinuous
500   range of the representation, then the client &MAY; store it as either a
501   multipart range response or as multiple <x:ref>206</x:ref> responses with
502   one continuous range each.
503</t>
504</section>
505</section>
506
507<section title="Header Field Definitions" anchor="header.field.definitions">
508<t>
509   This section defines the syntax and semantics of HTTP/1.1 header fields
510   related to range requests and partial responses.
511</t>
512
513<section title="Accept-Ranges" anchor="header.accept-ranges">
514  <iref primary="true" item="Accept-Ranges header field" x:for-anchor=""/>
515  <iref primary="true" item="Header Fields" subitem="Accept-Ranges" x:for-anchor=""/>
516  <x:anchor-alias value="Accept-Ranges"/>
517  <x:anchor-alias value="acceptable-ranges"/>
518<t>
519   The "Accept-Ranges" header field allows a resource to indicate
520   its acceptance of range requests.
521</t>
522<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Ranges"/><iref primary="true" item="Grammar" subitem="acceptable-ranges"/>
523  <x:ref>Accept-Ranges</x:ref>     = <x:ref>acceptable-ranges</x:ref>
524  <x:ref>acceptable-ranges</x:ref> = 1#<x:ref>range-unit</x:ref> / "none"
525</artwork></figure>
526<t>
527   Origin servers that accept byte-range requests &MAY; send
528</t>
529<figure><artwork type="example">
530  Accept-Ranges: bytes
531</artwork></figure>
532<t>
533   but are not required to do so. Clients &MAY; generate range
534   requests without having received this header field for the resource
535   involved. Range units are defined in <xref target="range.units"/>.
536</t>
537<t>
538   Servers that do not accept any kind of range request for a
539   resource &MAY; send
540</t>
541<figure><artwork type="example">
542  Accept-Ranges: none
543</artwork></figure>
544<t>
545   to advise the client not to attempt a range request.
546</t>
547</section>
548
549<section title="Content-Range" anchor="header.content-range">
550  <iref primary="true" item="Content-Range header field" x:for-anchor=""/>
551  <iref primary="true" item="Header Fields" subitem="Content-Range" x:for-anchor=""/>
552  <x:anchor-alias value="byte-content-range-spec"/>
553  <x:anchor-alias value="byte-range-resp-spec"/>
554  <x:anchor-alias value="Content-Range"/>
555  <x:anchor-alias value="instance-length"/>
556  <x:anchor-alias value="other-content-range-spec"/>
557  <x:anchor-alias value="other-range-resp-spec"/>
558<t>
559   The "Content-Range" header field is sent with a partial representation to
560   specify where in the full representation the payload body is intended to be
561   applied.
562</t>
563<t>   
564   Range units are defined in <xref target="range.units"/>.
565</t>
566<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Range"/><iref primary="true" item="Grammar" subitem="byte-content-range-spec"/><iref primary="true" item="Grammar" subitem="byte-range-resp-spec"/><iref primary="true" item="Grammar" subitem="instance-length"/>
567  <x:ref>Content-Range</x:ref>           = <x:ref>byte-content-range-spec</x:ref>
568                          / <x:ref>other-content-range-spec</x:ref>
569                         
570  <x:ref>byte-content-range-spec</x:ref> = <x:ref>bytes-unit</x:ref> <x:ref>SP</x:ref>
571                            <x:ref>byte-range-resp-spec</x:ref> "/"
572                            ( <x:ref>instance-length</x:ref> / "*" )
573 
574  <x:ref>byte-range-resp-spec</x:ref>    = (<x:ref>first-byte-pos</x:ref> "-" <x:ref>last-byte-pos</x:ref>)
575                          / "*"
576                         
577  <x:ref>instance-length</x:ref>         = 1*<x:ref>DIGIT</x:ref>
578 
579  <x:ref>other-content-range-spec</x:ref> = <x:ref>other-range-unit</x:ref> <x:ref>SP</x:ref>
580                             <x:ref>other-range-resp-spec</x:ref>
581  <x:ref>other-range-resp-spec</x:ref>    = *<x:ref>CHAR</x:ref>
582</artwork></figure>
583<t>
584   The header field &SHOULD; indicate the total length of the full representation,
585   unless this length is unknown or difficult to determine. The asterisk
586   "*" character means that the instance-length is unknown at the time
587   when the response was generated.
588</t>
589<t>
590   Unlike byte-ranges-specifier values (see <xref target="byte.ranges"/>), a byte-range-resp-spec
591   &MUST; only specify one range, and &MUST; contain
592   absolute byte positions for both the first and last byte of the
593   range.
594</t>
595<t>
596   A byte-content-range-spec with a byte-range-resp-spec whose last-byte-pos
597   value is less than its first-byte-pos value, or whose
598   instance-length value is less than or equal to its last-byte-pos
599   value, is invalid. The recipient of an invalid byte-content-range-spec
600   &MUST; ignore it and any content transferred along with it.
601</t>
602<t>
603   In the case of a byte range request:
604   A server sending a response with status code <x:ref>416 (Requested Range Not
605   Satisfiable)</x:ref> &SHOULD; include a Content-Range field with a byte-range-resp-spec
606   of "*". The instance-length specifies the current length of
607   the selected resource. A response with status code <x:ref>206 (Partial Content)</x:ref>
608   &MUST-NOT; include a Content-Range field with a byte-range-resp-spec of "*".
609</t>
610<t>
611  The "Content-Range" header field has no meaning for status codes that do not
612  explicitly describe its semantic. Currently, only status codes
613  <x:ref>206 (Partial Content)</x:ref> and <x:ref>416 (Requested Range Not Satisfiable)</x:ref> describe
614  the meaning of this header field.
615</t>
616<t>
617   Examples of byte-content-range-spec values, assuming that the representation
618   contains a total of 1234 bytes:
619   <list style="symbols">
620      <t>
621        The first 500 bytes:
622<figure><artwork type="example" x:indent-with="   ">
623  bytes 0-499/1234
624</artwork></figure>
625      </t>   
626      <t>
627        The second 500 bytes:
628<figure><artwork type="example" x:indent-with="   ">
629  bytes 500-999/1234
630</artwork></figure>
631      </t>   
632      <t>
633        All except for the first 500 bytes:
634<figure><artwork type="example" x:indent-with="   ">
635  bytes 500-1233/1234
636</artwork></figure>
637      </t>   
638      <t>
639        The last 500 bytes:
640<figure><artwork type="example" x:indent-with="   ">
641  bytes 734-1233/1234
642</artwork></figure>
643      </t>   
644   </list>
645</t>
646<t>
647   If the server ignores a byte-range-spec (for example if it is
648   syntactically invalid, or if it might be seen as a denial-of-service
649   attack), the server &SHOULD; treat the request as if the invalid <x:ref>Range</x:ref>
650   header field did not exist. (Normally, this means return a <x:ref>200 (OK)</x:ref>
651   response containing the full representation).
652</t>
653</section>
654
655<section title="If-Range" anchor="header.if-range">
656  <iref primary="true" item="If-Range header field" x:for-anchor=""/>
657  <iref primary="true" item="Header Fields" subitem="If-Range" x:for-anchor=""/>
658  <x:anchor-alias value="If-Range"/>
659<t>
660   If a client has a partial copy of a representation and wishes
661   to have an up-to-date copy of the entire representation, it could use the
662   <x:ref>Range</x:ref> header field with a conditional GET (using
663   either or both of <x:ref>If-Unmodified-Since</x:ref> and
664   <x:ref>If-Match</x:ref>.) However, if the condition fails because the
665   representation has been modified, the client would then have to make a
666   second request to obtain the entire current representation.
667</t>
668<t>
669   The "If-Range" header field allows a client to "short-circuit" the second
670   request. Informally, its meaning is "if the representation is unchanged, send
671   me the part(s) that I am missing; otherwise, send me the entire new
672   representation".
673</t>
674<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="If-Range"/>
675  <x:ref>If-Range</x:ref> = <x:ref>entity-tag</x:ref> / <x:ref>HTTP-date</x:ref>
676</artwork></figure>
677<t>
678   Clients &MUST-NOT; use an entity-tag marked as weak in an If-Range
679   field value and &MUST-NOT; use a <x:ref>Last-Modified</x:ref> date in an
680   If-Range field value unless it has no entity-tag for the representation and
681   the Last-Modified date it does have for the representation is strong
682   in the sense defined by &lastmod-comparison;.
683</t>
684<t>
685   A server that evaluates a conditional range request that is applicable
686   to one of its representations &MUST; evaluate the condition as false if
687   the entity-tag used as a validator is marked as weak or, when an HTTP-date
688   is used as the validator, if the date value is not strong in the sense
689   defined by &lastmod-comparison;. (A server can distinguish between a
690   valid HTTP-date and any form of entity-tag by examining the first
691   two characters.)
692</t>
693<t>
694   The If-Range header field &SHOULD; only be sent by clients together with
695   a Range header field.  The If-Range header field &MUST; be ignored if it
696   is received in a request that does not include a Range header field.
697   The If-Range header field &MUST; be ignored by a server that does not
698   support the sub-range operation.
699</t>
700<t>
701   If the validator given in the If-Range header field matches the current
702   validator for the selected representation of the target resource, then
703   the server &SHOULD; send the specified sub-range of the representation
704   using a <x:ref>206 (Partial Content)</x:ref> response. If the validator does not match,
705   then the server &SHOULD; send the entire representation using a <x:ref>200 (OK)</x:ref>
706   response.
707</t>
708</section>
709
710<section title="Range" anchor="header.range">
711  <iref primary="true" item="Range header field" x:for-anchor=""/>
712  <iref primary="true" item="Header Fields" subitem="Range" x:for-anchor=""/>
713
714<section title="Byte Ranges" anchor="byte.ranges">
715<t>
716   Since all HTTP representations are transferred as sequences
717   of bytes, the concept of a byte range is meaningful for any HTTP
718   representation. (However, not all clients and servers need to support byte-range
719   operations.)
720</t>
721<t>
722   Byte range specifications in HTTP apply to the sequence of bytes in
723   the representation body (not necessarily the same as the message body).
724</t>
725<t anchor="rule.ranges-specifier">
726  <x:anchor-alias value="byte-range-set"/>
727  <x:anchor-alias value="byte-range-spec"/>
728  <x:anchor-alias value="byte-ranges-specifier"/>
729  <x:anchor-alias value="first-byte-pos"/>
730  <x:anchor-alias value="last-byte-pos"/>
731  <x:anchor-alias value="ranges-specifier"/>
732  <x:anchor-alias value="suffix-byte-range-spec"/>
733  <x:anchor-alias value="suffix-length"/>
734   A byte range operation &MAY; specify a single range of bytes, or a set
735   of ranges within a single representation.
736</t>
737<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="ranges-specifier"/><iref primary="true" item="Grammar" subitem="byte-ranges-specifier"/><iref primary="true" item="Grammar" subitem="byte-range-set"/><iref primary="true" item="Grammar" subitem="byte-range-spec"/><iref primary="true" item="Grammar" subitem="first-byte-pos"/><iref primary="true" item="Grammar" subitem="last-byte-pos"/>
738  <x:ref>byte-ranges-specifier</x:ref> = <x:ref>bytes-unit</x:ref> "=" <x:ref>byte-range-set</x:ref>
739  <x:ref>byte-range-set</x:ref>  = 1#( <x:ref>byte-range-spec</x:ref> / <x:ref>suffix-byte-range-spec</x:ref> )
740  <x:ref>byte-range-spec</x:ref> = <x:ref>first-byte-pos</x:ref> "-" [ <x:ref>last-byte-pos</x:ref> ]
741  <x:ref>first-byte-pos</x:ref>  = 1*<x:ref>DIGIT</x:ref>
742  <x:ref>last-byte-pos</x:ref>   = 1*<x:ref>DIGIT</x:ref>
743</artwork></figure>
744<t>
745   The first-byte-pos value in a byte-range-spec gives the byte-offset
746   of the first byte in a range. The last-byte-pos value gives the
747   byte-offset of the last byte in the range; that is, the byte
748   positions specified are inclusive. Byte offsets start at zero.
749</t>
750<t>
751   If the last-byte-pos value is present, it &MUST; be greater than or
752   equal to the first-byte-pos in that byte-range-spec, or the byte-range-spec
753   is syntactically invalid. The recipient of a byte-range-set
754   that includes one or more syntactically invalid byte-range-spec
755   values &MUST; ignore the header field that includes that byte-range-set.
756</t>
757<t>
758   If the last-byte-pos value is absent, or if the value is greater than
759   or equal to the current length of the representation body, last-byte-pos is
760   taken to be equal to one less than the current length of the representation
761   in bytes.
762</t>
763<t>
764   By its choice of last-byte-pos, a client can limit the number of
765   bytes retrieved without knowing the size of the representation.
766</t>
767<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="suffix-byte-range-spec"/><iref primary="true" item="Grammar" subitem="suffix-length"/>
768  <x:ref>suffix-byte-range-spec</x:ref> = "-" <x:ref>suffix-length</x:ref>
769  <x:ref>suffix-length</x:ref> = 1*<x:ref>DIGIT</x:ref>
770</artwork></figure>
771<t>
772   A suffix-byte-range-spec is used to specify the suffix of the
773   representation body, of a length given by the suffix-length value. (That is,
774   this form specifies the last N bytes of a representation.) If the
775   representation is shorter than the specified suffix-length, the entire
776   representation is used.
777</t>
778<t>
779   If a syntactically valid byte-range-set includes at least one byte-range-spec
780   whose first-byte-pos is less than the current length of
781   the representation, or at least one suffix-byte-range-spec with a non-zero
782   suffix-length, then the byte-range-set is satisfiable.
783   Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set
784   is unsatisfiable, the server &SHOULD; return a response with a
785   <x:ref>416 (Requested Range Not Satisfiable)</x:ref> status code. Otherwise, the server
786   &SHOULD; return a response with a <x:ref>206 (Partial Content)</x:ref> status code
787   containing the satisfiable ranges of the representation.
788</t>
789<t>
790   In the byte range syntax, <x:ref>first-byte-pos</x:ref>,
791   <x:ref>last-byte-pos</x:ref>, and <x:ref>suffix-length</x:ref> are
792   expressed as decimal number of octets.  Since there is no predefined limit
793   to the length of an HTTP payload, recipients &SHOULD; anticipate
794   potentially large decimal numerals and prevent parsing errors due to integer
795   conversion overflows.
796</t>
797<t>
798   Examples of byte-ranges-specifier values (assuming a representation of
799   length 10000):
800  <list style="symbols">
801     <t>The first 500 bytes (byte offsets 0-499, inclusive):
802<figure><artwork type="example" x:indent-with="   ">
803  bytes=0-499
804</artwork></figure>
805    </t>
806     <t>The second 500 bytes (byte offsets 500-999, inclusive):
807<figure><artwork type="example" x:indent-with="   ">
808  bytes=500-999
809</artwork></figure>
810    </t>
811     <t>The final 500 bytes (byte offsets 9500-9999, inclusive):
812<figure><artwork type="example" x:indent-with="   ">
813  bytes=-500
814</artwork></figure>
815    Or:
816<figure><artwork type="example" x:indent-with="   ">
817  bytes=9500-
818</artwork></figure>
819    </t>
820     <t>The first and last bytes only (bytes 0 and 9999):
821<figure><artwork type="example" x:indent-with="   ">
822  bytes=0-0,-1
823</artwork></figure>
824     </t>
825     <t>Several legal but not canonical specifications of the second 500
826        bytes (byte offsets 500-999, inclusive):
827<figure><artwork type="example" x:indent-with="   ">
828  bytes=500-600,601-999
829  bytes=500-700,601-999
830</artwork></figure>
831     </t>
832  </list>
833</t>
834</section>
835
836<section title="Range Retrieval Requests" anchor="range.retrieval.requests">
837  <x:anchor-alias value="Range"/>
838  <x:anchor-alias value="other-ranges-specifier"/>
839  <x:anchor-alias value="other-range-set"/>
840<t>
841   The "Range" header field defines the GET method (conditional or
842   not) to request one or more sub-ranges of the response representation body, instead
843   of the entire representation body.
844</t>
845<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Range"/>
846  <x:ref>Range</x:ref> = <x:ref>byte-ranges-specifier</x:ref> / <x:ref>other-ranges-specifier</x:ref>
847  <x:ref>other-ranges-specifier</x:ref> = <x:ref>other-range-unit</x:ref> "=" <x:ref>other-range-set</x:ref>
848  <x:ref>other-range-set</x:ref> = 1*<x:ref>CHAR</x:ref>
849</artwork></figure>
850<t>
851   A server &MAY; ignore the Range header field. However, origin
852   servers and intermediate caches ought to support byte ranges when
853   possible, since Range supports efficient recovery from partially
854   failed transfers, and supports efficient partial retrieval of large
855   representations.
856</t>
857<t>
858   If the server supports the Range header field and the specified range or
859   ranges are appropriate for the representation:
860  <list style="symbols">
861     <t>The presence of a Range header field in an unconditional GET modifies
862        what is returned if the GET is otherwise successful. In other
863        words, the response carries a status code of <x:ref>206 (Partial Content)</x:ref>
864        instead of <x:ref>200 (OK)</x:ref>.</t>
865
866     <t>The presence of a Range header field in a conditional GET (a request
867        using one or both of <x:ref>If-Modified-Since</x:ref> and
868        <x:ref>If-None-Match</x:ref>, or one or both of
869        <x:ref>If-Unmodified-Since</x:ref> and <x:ref>If-Match</x:ref>) modifies
870        what is returned if the GET is otherwise successful and the
871        condition is true. It does not affect the <x:ref>304 (Not Modified)</x:ref>
872        response returned if the conditional is false.</t>
873  </list>
874</t>
875<t>
876   In some cases, it might be more appropriate to use the If-Range
877   header field (see <xref target="header.if-range"/>) in addition to the Range
878   header field.
879</t>
880<t>
881   If a proxy that supports ranges receives a Range request, forwards
882   the request to an inbound server, and receives an entire representation in
883   reply, it &MAY; only return the requested range to its client.
884</t>
885</section>
886</section>
887</section>
888
889<section title="IANA Considerations" anchor="IANA.considerations">
890
891<section title="Status Code Registration" anchor="status.code.registration">
892<t>
893   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
894   shall be updated with the registrations below:
895</t>
896<?BEGININC p5-range.iana-status-codes ?>
897<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
898<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
899   <ttcol>Value</ttcol>
900   <ttcol>Description</ttcol>
901   <ttcol>Reference</ttcol>
902   <c>206</c>
903   <c>Partial Content</c>
904   <c>
905      <xref target="status.206"/>
906   </c>
907   <c>416</c>
908   <c>Requested Range Not Satisfiable</c>
909   <c>
910      <xref target="status.416"/>
911   </c>
912</texttable>
913<!--(END)-->
914<?ENDINC p5-range.iana-status-codes ?>
915</section>
916
917<section title="Header Field Registration" anchor="header.field.registration">
918<t>
919   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
920   with the permanent registrations below (see <xref target="RFC3864"/>):
921</t>
922<?BEGININC p5-range.iana-headers ?>
923<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
924<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
925   <ttcol>Header Field Name</ttcol>
926   <ttcol>Protocol</ttcol>
927   <ttcol>Status</ttcol>
928   <ttcol>Reference</ttcol>
929
930   <c>Accept-Ranges</c>
931   <c>http</c>
932   <c>standard</c>
933   <c>
934      <xref target="header.accept-ranges"/>
935   </c>
936   <c>Content-Range</c>
937   <c>http</c>
938   <c>standard</c>
939   <c>
940      <xref target="header.content-range"/>
941   </c>
942   <c>If-Range</c>
943   <c>http</c>
944   <c>standard</c>
945   <c>
946      <xref target="header.if-range"/>
947   </c>
948   <c>Range</c>
949   <c>http</c>
950   <c>standard</c>
951   <c>
952      <xref target="header.range"/>
953   </c>
954</texttable>
955<!--(END)-->
956<?ENDINC p5-range.iana-headers ?>
957<t>
958   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
959</t>
960</section>
961
962<section title="Range Specifier Registration" anchor="range.specifier.registration">
963<t>
964  The registration procedure for HTTP Range Specifiers is defined by
965  <xref target="range.specifier.registry"/> of this document.
966</t>
967<t>
968   The HTTP Range Specifier Registry shall be created at <eref target="http://www.iana.org/assignments/http-range-specifiers"/>
969   and be populated with the registrations below:
970</t>
971<texttable align="left" suppress-title="true" anchor="iana.range.specifiers.table">
972   <ttcol>Range Specifier Name</ttcol>
973   <ttcol>Description</ttcol>
974   <ttcol>Reference</ttcol>
975
976   <c>bytes</c>
977   <c>a range of octets</c>
978   <c><xref target="range.units"/></c>
979
980   <c>none</c>
981   <c>reserved as keyword, indicating no ranges are supported</c>
982   <c><xref target="header.accept-ranges"/></c>
983</texttable>
984<t>
985   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
986</t>
987</section>
988</section>
989
990<section title="Security Considerations" anchor="security.considerations">
991<t>
992   This section is meant to inform application developers, information
993   providers, and users of the security limitations in HTTP/1.1 as
994   described by this document. The discussion does not include
995   definitive solutions to the problems revealed, though it does make
996   some suggestions for reducing security risks.
997</t>
998<section title="Overlapping Ranges" anchor="overlapping.ranges">
999<t>
1000   Range requests containing overlapping ranges can lead to the situation
1001   where a server is sending far more data than the size of the complete
1002   resource representation.
1003</t>
1004</section>
1005</section>
1006
1007<section title="Acknowledgments" anchor="acks">
1008<t>
1009  See &acks;.
1010</t>
1011</section>
1012</middle>
1013<back>
1014
1015<references title="Normative References">
1016
1017<reference anchor="Part1">
1018  <front>
1019    <title>HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1020    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1021      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1022      <address><email>fielding@gbiv.com</email></address>
1023    </author>
1024    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1025      <organization abbrev="W3C">World Wide Web Consortium</organization>
1026      <address><email>ylafon@w3.org</email></address>
1027    </author>
1028    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1029      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1030      <address><email>julian.reschke@greenbytes.de</email></address>
1031    </author>
1032    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1033  </front>
1034  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1035  <x:source href="p1-messaging.xml" basename="p1-messaging">
1036    <x:defines>Content-Length</x:defines>
1037  </x:source>
1038</reference>
1039
1040<reference anchor="Part2">
1041  <front>
1042    <title>HTTP/1.1, part 2: Message Semantics, Payload and Content Negotiation</title>
1043    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1044      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1045      <address><email>fielding@gbiv.com</email></address>
1046    </author>
1047    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1048      <organization abbrev="W3C">World Wide Web Consortium</organization>
1049      <address><email>ylafon@w3.org</email></address>
1050    </author>
1051    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1052      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1053      <address><email>julian.reschke@greenbytes.de</email></address>
1054    </author>
1055    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1056  </front>
1057  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1058  <x:source href="p2-semantics.xml" basename="p2-semantics">
1059    <x:defines>200 (OK)</x:defines>
1060    <x:defines>410 (Gone)</x:defines>
1061    <x:defines>Content-Location</x:defines>
1062    <x:defines>Content-Type</x:defines>
1063    <x:defines>Location</x:defines>
1064  </x:source>
1065</reference>
1066
1067<reference anchor="Part4">
1068  <front>
1069    <title>HTTP/1.1, part 4: Conditional Requests</title>
1070    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1071      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1072      <address><email>fielding@gbiv.com</email></address>
1073    </author>
1074    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1075      <organization abbrev="W3C">World Wide Web Consortium</organization>
1076      <address><email>ylafon@w3.org</email></address>
1077    </author>
1078    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1079      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1080      <address><email>julian.reschke@greenbytes.de</email></address>
1081    </author>
1082    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1083  </front>
1084  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1085  <x:source href="p4-conditional.xml" basename="p4-conditional">
1086    <x:defines>304 (Not Modified)</x:defines>
1087    <x:defines>ETag</x:defines>
1088    <x:defines>If-Match</x:defines>
1089    <x:defines>If-Modified-Since</x:defines>
1090    <x:defines>If-None-Match</x:defines>
1091    <x:defines>If-Unmodified-Since</x:defines>
1092    <x:defines>Last-Modified</x:defines>
1093  </x:source>
1094</reference>
1095
1096<reference anchor="Part6">
1097  <front>
1098    <title>HTTP/1.1, part 6: Caching</title>
1099    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1100      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1101      <address><email>fielding@gbiv.com</email></address>
1102    </author>
1103    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1104      <organization abbrev="W3C">World Wide Web Consortium</organization>
1105      <address><email>ylafon@w3.org</email></address>
1106    </author>
1107    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1108      <organization>Rackspace</organization>
1109      <address><email>mnot@mnot.net</email></address>
1110    </author>
1111    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1112      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1113      <address><email>julian.reschke@greenbytes.de</email></address>
1114    </author>
1115    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1116  </front>
1117  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1118  <x:source href="p6-cache.xml" basename="p6-cache">
1119    <x:defines>Cache-Control</x:defines>
1120    <x:defines>Expires</x:defines>
1121    <x:defines>Vary</x:defines>
1122  </x:source>
1123</reference>
1124
1125<reference anchor="RFC2046">
1126  <front>
1127    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1128    <author initials="N." surname="Freed" fullname="Ned Freed">
1129      <organization>Innosoft International, Inc.</organization>
1130      <address><email>ned@innosoft.com</email></address>
1131    </author>
1132    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1133      <organization>First Virtual Holdings</organization>
1134      <address><email>nsb@nsb.fv.com</email></address>
1135    </author>
1136    <date month="November" year="1996"/>
1137  </front>
1138  <seriesInfo name="RFC" value="2046"/>
1139</reference>
1140
1141<reference anchor="RFC2119">
1142  <front>
1143    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1144    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1145      <organization>Harvard University</organization>
1146      <address><email>sob@harvard.edu</email></address>
1147    </author>
1148    <date month="March" year="1997"/>
1149  </front>
1150  <seriesInfo name="BCP" value="14"/>
1151  <seriesInfo name="RFC" value="2119"/>
1152</reference>
1153
1154<reference anchor="RFC5234">
1155  <front>
1156    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1157    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1158      <organization>Brandenburg InternetWorking</organization>
1159      <address>
1160        <email>dcrocker@bbiw.net</email>
1161      </address> 
1162    </author>
1163    <author initials="P." surname="Overell" fullname="Paul Overell">
1164      <organization>THUS plc.</organization>
1165      <address>
1166        <email>paul.overell@thus.net</email>
1167      </address>
1168    </author>
1169    <date month="January" year="2008"/>
1170  </front>
1171  <seriesInfo name="STD" value="68"/>
1172  <seriesInfo name="RFC" value="5234"/>
1173</reference>
1174
1175</references>
1176
1177<references title="Informative References">
1178
1179<reference anchor="RFC2616">
1180  <front>
1181    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
1182    <author initials="R." surname="Fielding" fullname="R. Fielding">
1183      <organization>University of California, Irvine</organization>
1184      <address><email>fielding@ics.uci.edu</email></address>
1185    </author>
1186    <author initials="J." surname="Gettys" fullname="J. Gettys">
1187      <organization>W3C</organization>
1188      <address><email>jg@w3.org</email></address>
1189    </author>
1190    <author initials="J." surname="Mogul" fullname="J. Mogul">
1191      <organization>Compaq Computer Corporation</organization>
1192      <address><email>mogul@wrl.dec.com</email></address>
1193    </author>
1194    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
1195      <organization>MIT Laboratory for Computer Science</organization>
1196      <address><email>frystyk@w3.org</email></address>
1197    </author>
1198    <author initials="L." surname="Masinter" fullname="L. Masinter">
1199      <organization>Xerox Corporation</organization>
1200      <address><email>masinter@parc.xerox.com</email></address>
1201    </author>
1202    <author initials="P." surname="Leach" fullname="P. Leach">
1203      <organization>Microsoft Corporation</organization>
1204      <address><email>paulle@microsoft.com</email></address>
1205    </author>
1206    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
1207      <organization>W3C</organization>
1208      <address><email>timbl@w3.org</email></address>
1209    </author>
1210    <date month="June" year="1999"/>
1211  </front>
1212  <seriesInfo name="RFC" value="2616"/>
1213</reference>
1214
1215<reference anchor='RFC3864'>
1216  <front>
1217    <title>Registration Procedures for Message Header Fields</title>
1218    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
1219      <organization>Nine by Nine</organization>
1220      <address><email>GK-IETF@ninebynine.org</email></address>
1221    </author>
1222    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
1223      <organization>BEA Systems</organization>
1224      <address><email>mnot@pobox.com</email></address>
1225    </author>
1226    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
1227      <organization>HP Labs</organization>
1228      <address><email>JeffMogul@acm.org</email></address>
1229    </author>
1230    <date year='2004' month='September' />
1231  </front>
1232  <seriesInfo name='BCP' value='90' />
1233  <seriesInfo name='RFC' value='3864' />
1234</reference>
1235
1236<reference anchor="RFC4288">
1237  <front>
1238    <title>Media Type Specifications and Registration Procedures</title>
1239    <author initials="N." surname="Freed" fullname="N. Freed">
1240      <organization>Sun Microsystems</organization>
1241      <address>
1242        <email>ned.freed@mrochek.com</email>
1243      </address>
1244    </author>
1245    <author initials="J." surname="Klensin" fullname="J. Klensin">
1246      <address>
1247        <email>klensin+ietf@jck.com</email>
1248      </address>
1249    </author>
1250    <date year="2005" month="December"/>
1251  </front>
1252  <seriesInfo name="BCP" value="13"/>
1253  <seriesInfo name="RFC" value="4288"/>
1254</reference>
1255
1256<reference anchor='RFC5226'>
1257  <front>
1258    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1259    <author initials='T.' surname='Narten' fullname='T. Narten'>
1260      <organization>IBM</organization>
1261      <address><email>narten@us.ibm.com</email></address>
1262    </author>
1263    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1264      <organization>Google</organization>
1265      <address><email>Harald@Alvestrand.no</email></address>
1266    </author>
1267    <date year='2008' month='May' />
1268  </front>
1269  <seriesInfo name='BCP' value='26' />
1270  <seriesInfo name='RFC' value='5226' />
1271</reference>
1272
1273</references>
1274
1275<section title="Internet Media Type multipart/byteranges" anchor="internet.media.type.multipart.byteranges">
1276<iref item="Media Type" subitem="multipart/byteranges" primary="true"/>
1277<iref item="multipart/byteranges Media Type" primary="true"/>
1278<t>
1279   When an HTTP <x:ref>206 (Partial Content)</x:ref> response message includes the
1280   content of multiple ranges (a response to a request for multiple
1281   non-overlapping ranges), these are transmitted as a multipart
1282   message body (<xref target="RFC2046" x:fmt="," x:sec="5.1"/>). The media type for this purpose is called
1283   "multipart/byteranges".  The following is to be registered with IANA <xref target="RFC4288"/>.
1284</t>
1285<t>
1286   The multipart/byteranges media type includes one or more parts, each
1287   with its own <x:ref>Content-Type</x:ref> and <x:ref>Content-Range</x:ref>
1288   fields. The required boundary parameter specifies the boundary string used
1289   to separate each body-part.
1290</t>
1291<t>
1292  <list style="hanging" x:indent="12em">
1293    <t hangText="Type name:">
1294      multipart
1295    </t>
1296    <t hangText="Subtype name:">
1297      byteranges
1298    </t>
1299    <t hangText="Required parameters:">
1300      boundary
1301    </t>
1302    <t hangText="Optional parameters:">
1303      none
1304    </t>
1305    <t hangText="Encoding considerations:">
1306      only "7bit", "8bit", or "binary" are permitted
1307    </t>
1308    <t hangText="Security considerations:">
1309      none
1310    </t>
1311    <t hangText="Interoperability considerations:">
1312      none
1313    </t>
1314    <t hangText="Published specification:">
1315      This specification (see <xref target="internet.media.type.multipart.byteranges"/>).
1316    </t>
1317    <t hangText="Applications that use this media type:">
1318      HTTP components supporting multiple ranges in a single request.
1319    </t>
1320    <t hangText="Additional information:">
1321      <list style="hanging">
1322        <t hangText="Magic number(s):">none</t>
1323        <t hangText="File extension(s):">none</t>
1324        <t hangText="Macintosh file type code(s):">none</t>
1325      </list>
1326    </t>
1327    <t hangText="Person and email address to contact for further information:">
1328      See Authors Section.
1329    </t>
1330    <t hangText="Intended usage:">
1331      COMMON
1332    </t>
1333    <t hangText="Restrictions on usage:">
1334      none
1335    </t>
1336    <t hangText="Author/Change controller:">
1337      IESG
1338    </t>
1339  </list>
1340</t>
1341<x:note>
1342  <t>
1343    &Note; Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1344  </t>
1345</x:note>
1346<figure><preamble>
1347   For example:
1348</preamble><artwork type="example">
1349  HTTP/1.1 206 Partial Content
1350  Date: Wed, 15 Nov 1995 06:25:24 GMT
1351  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1352  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1353 
1354  --THIS_STRING_SEPARATES
1355  Content-type: application/pdf
1356  Content-range: bytes 500-999/8000
1357 
1358  ...the first range...
1359  --THIS_STRING_SEPARATES
1360  Content-type: application/pdf
1361  Content-range: bytes 7000-7999/8000
1362 
1363  ...the second range
1364  --THIS_STRING_SEPARATES--
1365</artwork></figure>
1366<figure><preamble>
1367   Another example, using the "exampleunit" range unit:
1368</preamble>
1369<artwork type="example">
1370  HTTP/1.1 206 Partial Content
1371  Date: Tue, 14 Nov 1995 06:25:24 GMT
1372  Last-Modified: Tue, 14 July 04:58:08 GMT
1373  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1374 
1375  --THIS_STRING_SEPARATES
1376  Content-type: video/example
1377  Content-range: exampleunit 1.2-4.3/25
1378 
1379  ...the first range...
1380  --THIS_STRING_SEPARATES
1381  Content-type: video/example
1382  Content-range: exampleunit 11.2-14.3/25
1383 
1384  ...the second range
1385  --THIS_STRING_SEPARATES--
1386</artwork>
1387</figure>
1388<t>
1389  Notes:
1390  <list style="numbers">
1391      <t>Additional CRLFs &MAY; precede the first boundary string in the body.</t>
1392
1393      <t>Although <xref target="RFC2046"/> permits the boundary string to be
1394         quoted, some existing implementations handle a quoted boundary
1395         string incorrectly.</t>
1396
1397      <t>A number of clients and servers were coded to an early draft
1398         of the byteranges specification to use a media type of
1399         multipart/x-byteranges<iref item="multipart/x-byteranges Media Type"/><iref item="Media Type" subitem="multipart/x-byteranges"/>, which is almost, but not quite
1400         compatible with the version documented in HTTP/1.1.</t>
1401  </list>
1402</t>
1403</section>
1404
1405<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
1406<t>
1407  Introduce Range Specifier Registry.
1408  (<xref target="range.specifier.registry"/>)
1409</t>
1410<t>
1411  Clarify that it is not ok to use a weak validator in a <x:ref>206</x:ref> response.
1412  (<xref target="status.206"/>)
1413</t>
1414<t>
1415  Change ABNF productions for header fields to only define the field value.
1416  (<xref target="header.field.definitions"/>)
1417</t>
1418<t>
1419  Clarify that multipart/byteranges can consist of a single part.
1420  (<xref target="internet.media.type.multipart.byteranges"/>)
1421</t>
1422</section>
1423
1424<?BEGININC p5-range.abnf-appendix ?>
1425<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1426<figure>
1427<artwork type="abnf" name="p5-range.parsed-abnf">
1428<x:ref>Accept-Ranges</x:ref> = acceptable-ranges
1429
1430<x:ref>Content-Range</x:ref> = byte-content-range-spec / other-content-range-spec
1431
1432<x:ref>HTTP-date</x:ref> = &lt;HTTP-date, defined in [Part2], Section 5.1&gt;
1433
1434<x:ref>If-Range</x:ref> = entity-tag / HTTP-date
1435
1436<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 3.2.1&gt;
1437
1438<x:ref>Range</x:ref> = byte-ranges-specifier / other-ranges-specifier
1439
1440<x:ref>acceptable-ranges</x:ref> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1441 range-unit ] ) ) / "none"
1442
1443<x:ref>byte-content-range-spec</x:ref> = bytes-unit SP byte-range-resp-spec "/" (
1444 instance-length / "*" )
1445<x:ref>byte-range-resp-spec</x:ref> = ( first-byte-pos "-" last-byte-pos ) / "*"
1446<x:ref>byte-range-set</x:ref> = *( "," OWS ) ( byte-range-spec /
1447 suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
1448 suffix-byte-range-spec ) ] )
1449<x:ref>byte-range-spec</x:ref> = first-byte-pos "-" [ last-byte-pos ]
1450<x:ref>byte-ranges-specifier</x:ref> = bytes-unit "=" byte-range-set
1451<x:ref>bytes-unit</x:ref> = "bytes"
1452
1453<x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in [Part4], Section 2.3&gt;
1454
1455<x:ref>first-byte-pos</x:ref> = 1*DIGIT
1456
1457<x:ref>instance-length</x:ref> = 1*DIGIT
1458
1459<x:ref>last-byte-pos</x:ref> = 1*DIGIT
1460
1461<x:ref>other-content-range-spec</x:ref> = other-range-unit SP other-range-resp-spec
1462<x:ref>other-range-resp-spec</x:ref> = *CHAR
1463<x:ref>other-range-set</x:ref> = 1*CHAR
1464<x:ref>other-range-unit</x:ref> = token
1465<x:ref>other-ranges-specifier</x:ref> = other-range-unit "=" other-range-set
1466
1467<x:ref>range-unit</x:ref> = bytes-unit / other-range-unit
1468
1469<x:ref>suffix-byte-range-spec</x:ref> = "-" suffix-length
1470<x:ref>suffix-length</x:ref> = 1*DIGIT
1471
1472<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.4&gt;
1473</artwork>
1474</figure>
1475</section>
1476<?ENDINC p5-range.abnf-appendix ?>
1477
1478
1479<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
1480
1481<section title="Since RFC 2616">
1482<t>
1483  Extracted relevant partitions from <xref target="RFC2616"/>.
1484</t>
1485</section>
1486
1487<section title="Since draft-ietf-httpbis-p5-range-00">
1488<t>
1489  Closed issues:
1490  <list style="symbols"> 
1491    <t>
1492      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/18"/>:
1493      "Cache validators in 206 responses"
1494      (<eref target="http://purl.org/NET/http-errata#ifrange206"/>)
1495    </t>
1496    <t>
1497      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
1498      "Normative and Informative references"
1499    </t>
1500    <t>
1501      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
1502      "Normative up-to-date references"
1503    </t>
1504  </list>
1505</t>
1506</section>
1507
1508<section title="Since draft-ietf-httpbis-p5-range-01">
1509<t>
1510  Closed issues:
1511  <list style="symbols"> 
1512    <t>
1513      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
1514      "Updating to RFC4288"
1515    </t>
1516  </list>
1517</t>
1518<t>
1519  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1520  <list style="symbols"> 
1521    <t>
1522      Add explicit references to BNF syntax and rules imported from other parts of the specification.
1523    </t>
1524  </list>
1525</t>
1526</section>
1527
1528<section title="Since draft-ietf-httpbis-p5-range-02" anchor="changes.since.02">
1529<t>
1530  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
1531  <list style="symbols"> 
1532    <t>
1533      Reference RFC 3984, and update header field registrations for headers defined
1534      in this document.
1535    </t>
1536  </list>
1537</t>
1538</section>
1539
1540<section title="Since draft-ietf-httpbis-p5-range-03" anchor="changes.since.03">
1541<t>
1542  None.
1543</t>
1544</section>
1545
1546<section title="Since draft-ietf-httpbis-p5-range-04" anchor="changes.since.04">
1547<t>
1548  Closed issues:
1549  <list style="symbols"> 
1550    <t>
1551      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/133"/>:
1552      "multipart/byteranges minimum number of parts"
1553    </t>
1554  </list>
1555</t>
1556<t>
1557  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1558  <list style="symbols"> 
1559    <t>
1560      Use "/" instead of "|" for alternatives.
1561    </t>
1562    <t>
1563      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
1564      whitespace ("OWS") and required whitespace ("RWS").
1565    </t>
1566    <t>
1567      Rewrite ABNFs to spell out whitespace rules, factor out
1568      header field value format definitions.
1569    </t>
1570  </list>
1571</t>
1572</section>
1573
1574<section title="Since draft-ietf-httpbis-p5-range-05" anchor="changes.since.05">
1575<t>
1576  Closed issues:
1577  <list style="symbols"> 
1578    <t>
1579      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/142"/>:
1580      "State base for *-byte-pos and suffix-length"
1581    </t>
1582  </list>
1583</t>
1584<t>
1585  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1586  <list style="symbols"> 
1587    <t>
1588      Remove bias in favor of byte ranges; allow custom ranges in ABNF.
1589    </t>
1590  </list>
1591</t>
1592<t>
1593  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1594  <list style="symbols"> 
1595    <t>
1596      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
1597    </t>
1598  </list>
1599</t>
1600</section>
1601
1602<section title="Since draft-ietf-httpbis-p5-range-06" anchor="changes.since.06">
1603<t>
1604  Closed issues:
1605  <list style="symbols"> 
1606    <t>
1607      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/161"/>:
1608      "base for numeric protocol elements"
1609    </t>
1610  </list>
1611</t>
1612</section>
1613
1614<section title="Since draft-ietf-httpbis-p5-range-07" anchor="changes.since.07">
1615<t>
1616  Closed issues:
1617  <list style="symbols">
1618    <t>
1619      Fixed discrepancy in the If-Range definition about allowed validators.
1620    </t>
1621    <t>
1622      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/150" />: "multipart/byteranges for custom range units"
1623    </t>
1624    <t>
1625      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/151" />: "range unit missing from other-ranges-specifier in Range header"
1626    </t>
1627    <t>
1628      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/198"/>:
1629      "move IANA registrations for optional status codes"
1630    </t>
1631  </list>
1632</t>
1633</section>
1634
1635<section title="Since draft-ietf-httpbis-p5-range-08" anchor="changes.since.08">
1636<t>
1637  No significant changes.
1638</t>
1639</section>
1640
1641<section title="Since draft-ietf-httpbis-p5-range-09" anchor="changes.since.09">
1642<t>
1643 No significant changes.
1644</t>
1645</section>
1646
1647<section title="Since draft-ietf-httpbis-p5-range-10" anchor="changes.since.10">
1648<t>
1649  Closed issues:
1650  <list style="symbols"> 
1651    <t>
1652      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
1653      "Clarify 'Requested Variant'"
1654    </t>
1655    <t>
1656      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
1657      "Clarify entity / representation / variant terminology"
1658    </t>
1659    <t>
1660      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
1661      "consider removing the 'changes from 2068' sections"
1662    </t>
1663  </list>
1664</t>
1665<t>
1666  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1667  <list style="symbols"> 
1668    <t>
1669      Add IANA registry.
1670    </t>
1671  </list>
1672</t>
1673</section>
1674
1675<section title="Since draft-ietf-httpbis-p5-range-11" anchor="changes.since.11">
1676<t>
1677  Closed issues:
1678  <list style="symbols"> 
1679    <t>
1680      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/217"/>:
1681      "Caches can't be required to serve ranges"
1682    </t>
1683  </list>
1684</t>
1685</section>
1686
1687<section title="Since draft-ietf-httpbis-p5-range-12" anchor="changes.since.12">
1688<t>
1689  Closed issues:
1690  <list style="symbols"> 
1691    <t>
1692      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
1693      "Header Classification"
1694    </t>
1695  </list>
1696</t>
1697</section>
1698
1699<section title="Since draft-ietf-httpbis-p5-range-13" anchor="changes.since.13">
1700<t>
1701  Closed issues:
1702  <list style="symbols">
1703    <t>
1704      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
1705      "untangle ABNFs for header fields"
1706    </t>
1707  </list>
1708</t>
1709</section>
1710
1711<section title="Since draft-ietf-httpbis-p5-range-14" anchor="changes.since.14">
1712<t>
1713  None.
1714</t>
1715</section>
1716
1717<section title="Since draft-ietf-httpbis-p5-range-15" anchor="changes.since.15">
1718<t>
1719  Closed issues:
1720  <list style="symbols">
1721    <t>
1722      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/175"/>:
1723      "Security consideration: range flooding"
1724    </t>
1725  </list>
1726</t>
1727</section>
1728
1729<section title="Since draft-ietf-httpbis-p5-range-16" anchor="changes.since.16">
1730<t>
1731  Closed issues:
1732  <list style="symbols"> 
1733    <t>
1734      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/186"/>:
1735      "Document HTTP's error-handling philosophy"
1736    </t>
1737    <t>
1738      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/301"/>:
1739      "Content-Range on responses other than 206"
1740    </t>
1741    <t>
1742      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/319"/>:
1743      "case sensitivity of ranges in p5"
1744    </t>
1745  </list>
1746</t>
1747</section>
1748
1749<section title="Since draft-ietf-httpbis-p5-range-17" anchor="changes.since.17">
1750<t>
1751  None.
1752</t>
1753</section>
1754
1755<section title="Since draft-ietf-httpbis-p5-range-18" anchor="changes.since.18">
1756<t>
1757  Closed issues:
1758  <list style="symbols"> 
1759    <t>
1760      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/311"/>:
1761      "Add limitations to Range to reduce its use as a denial-of-service tool"
1762    </t>
1763  </list>
1764</t>
1765</section>
1766
1767<section title="Since draft-ietf-httpbis-p5-range-19" anchor="changes.since.19">
1768<t>
1769  Closed issues:
1770  <list style="symbols"> 
1771    <t>
1772      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/358"/>:
1773      "ABNF list expansion code problem"
1774    </t>
1775    <t>
1776      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/361"/>:
1777      "ABNF requirements for recipients"
1778    </t>
1779    <t>
1780      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/367"/>:
1781      "reserve 'none' as byte range unit"
1782    </t>
1783    <t>
1784      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/368"/>:
1785      "note introduction of new IANA registries as normative changes"
1786    </t>
1787    <t>
1788      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/369"/>:
1789      "range units vs leading zeroes vs size"
1790    </t>
1791  </list>
1792</t>
1793</section>
1794
1795</section>
1796
1797</back>
1798</rfc>
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