source: draft-ietf-httpbis/latest/p5-range.xml @ 1748

Last change on this file since 1748 was 1748, checked in by julian.reschke@…, 7 years ago

reserve range unit name "none" (see #367)

  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/xml
File size: 67.3 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 ought to take 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 document defines conformance criteria for several roles in HTTP
168   communication, including Senders, Recipients, Clients, Servers, User-Agents,
169   Origin Servers, Intermediaries, Proxies and Gateways. See &architecture;
170   for definitions of these terms.
171</t>
172<t>
173   An implementation is considered conformant if it complies with all of the
174   requirements associated with its role(s). Note that SHOULD-level requirements
175   are relevant here, unless one of the documented exceptions is applicable.
176</t>
177<t>
178   This document also uses ABNF to define valid protocol elements
179   (<xref target="notation"/>). In addition to the prose requirements placed
180   upon them, Senders &MUST-NOT; generate protocol elements that are invalid.
181</t>
182<t>
183   Unless noted otherwise, Recipients &MUST; be able to parse all protocol
184   elements matching the ABNF rules defined for them and &MAY; take steps to
185   recover a usable protocol element from an invalid construct. However, HTTP does not define
186   specific error handling mechanisms, except in cases where it has direct
187   impact on security. This is because different uses of the protocol require
188   different error handling strategies; for example, a Web browser might wish to
189   transparently recover from a response where the <x:ref>Location</x:ref>
190   header field doesn't parse according to the ABNF, whereby in a systems
191   control protocol using HTTP, this type of error recovery could lead to
192   dangerous consequences.
193</t>
194</section>
195
196<section title="Syntax Notation" anchor="notation">
197  <x:anchor-alias value="ALPHA"/>
198  <x:anchor-alias value="CHAR"/>
199  <x:anchor-alias value="CR"/>
200  <x:anchor-alias value="DIGIT"/>
201  <x:anchor-alias value="LF"/>
202  <x:anchor-alias value="OCTET"/>
203  <x:anchor-alias value="SP"/>
204  <x:anchor-alias value="VCHAR"/>
205<t>
206   This specification uses the Augmented Backus-Naur Form (ABNF) notation
207   of <xref target="RFC5234"/> with the list rule extension defined in
208   &notation;<xref target="collected.abnf"/> shows the collected ABNF
209   with the list rule expanded.
210</t>
211<t>
212  The following core rules are included by
213  reference, as defined in <xref target="RFC5234" x:fmt="," x:sec="B.1"/>:
214  ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
215  DIGIT (decimal 0-9), DQUOTE (double quote),
216  HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
217  OCTET (any 8-bit sequence of data), SP (space), and
218  VCHAR (any visible US-ASCII character).
219</t>
220
221<t>
222  Note that all rules derived from <x:ref>token</x:ref> are to
223  be compared case-insensitively, like <x:ref>range-unit</x:ref> and
224  <x:ref>acceptable-ranges</x:ref>.
225</t>
226
227<section title="Core Rules" anchor="core.rules">
228  <x:anchor-alias value="token"/>
229  <x:anchor-alias value="OWS"/>
230  <x:anchor-alias value="HTTP-date"/>
231<t>
232  The core rules below are defined in <xref target="Part1"/> and
233  <xref target="Part2"/>:
234</t>
235<figure><artwork type="abnf2616">
236  <x:ref>OWS</x:ref>        = &lt;OWS, defined in &whitespace;&gt;
237  <x:ref>token</x:ref>      = &lt;token, defined in &field-components;&gt;
238  <x:ref>HTTP-date</x:ref>  = &lt;HTTP-date, defined in &http-date;&gt;
239</artwork></figure>
240</section>
241
242<section title="ABNF Rules defined in other Parts of the Specification" anchor="abnf.dependencies">
243  <x:anchor-alias value="entity-tag"/>
244<t>
245  The ABNF rules below are defined in other parts:
246</t>
247<figure><!--Part4--><artwork type="abnf2616">
248  <x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in &entity-tags;&gt;
249</artwork></figure>
250</section>
251
252</section>
253
254</section>
255
256
257<section title="Range Units" anchor="range.units">
258  <x:anchor-alias value="bytes-unit"/>
259  <x:anchor-alias value="other-range-unit"/>
260  <x:anchor-alias value="range-unit"/>
261<t>
262   HTTP/1.1 allows a client to request that only part (a range) of the
263   representation be included within the response. HTTP/1.1 uses range
264   units in the <x:ref>Range</x:ref> (<xref target="header.range"/>) and
265   <x:ref>Content-Range</x:ref> (<xref target="header.content-range"/>)
266   header fields. A representation can be broken down into subranges according
267   to various structural units.
268</t>
269<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"/>
270  <x:ref>range-unit</x:ref>       = <x:ref>bytes-unit</x:ref> / <x:ref>other-range-unit</x:ref>
271  <x:ref>bytes-unit</x:ref>       = "bytes"
272  <x:ref>other-range-unit</x:ref> = <x:ref>token</x:ref>
273</artwork></figure>
274<t>
275  HTTP/1.1 has been designed to allow implementations of applications
276  that do not depend on knowledge of ranges. The only range unit defined
277  by HTTP/1.1 is "bytes". Additional specifiers can be defined as described
278  in <xref target="range.specifier.registry"/>.
279</t>
280<t>
281  If a range unit is not understood in a request, a server &MUST; ignore
282  the whole <x:ref>Range</x:ref> header field (<xref target="header.range"/>).
283  If a range unit is not understood in a response, an intermediary
284  &SHOULD; pass the response to the client; a client &MUST; fail.
285</t>
286
287<section title="Range Specifier Registry" anchor="range.specifier.registry">
288<t>
289   The HTTP Range Specifier Registry defines the name space for the range
290   specifier names.
291</t>
292<t>
293   Registrations &MUST; include the following fields:
294   <list style="symbols">
295     <t>Name</t>
296     <t>Description</t>
297     <t>Pointer to specification text</t>
298   </list>
299</t>
300<t>
301  Values to be added to this name space require IETF Review
302  (see <xref target="RFC5226" x:fmt="," x:sec="4.1"/>).
303</t>
304<t>
305   The registry itself is maintained at
306   <eref target="http://www.iana.org/assignments/http-range-specifiers"/>.
307</t>
308</section>
309
310</section>
311
312<section title="Status Code Definitions" anchor="status.code.definitions">
313<section title="206 Partial Content" anchor="status.206">
314  <iref primary="true" item="206 Partial Content (status code)" x:for-anchor=""/>
315  <iref primary="true" item="Status Codes" subitem="206 Partial Content" x:for-anchor=""/>
316  <x:anchor-alias value="206"/>
317  <x:anchor-alias value="206 (Partial Content)"/>
318<t>
319   The server has fulfilled the partial GET request for the resource.
320   The request &MUST; have included a <x:ref>Range</x:ref> header field
321   (<xref target="header.range"/>) indicating the desired range, and &MAY; have
322   included an <x:ref>If-Range</x:ref> header field
323   (<xref target="header.if-range"/>) to make the request conditional.
324</t>
325<t>
326   The response &MUST; include the following header fields:
327  <list style="symbols">
328    <t>
329        Either a <x:ref>Content-Range</x:ref> header field
330        (<xref target="header.content-range"/>) indicating
331        the range included with this response, or a multipart/byteranges
332        <x:ref>Content-Type</x:ref> including Content-Range fields for each
333        part. If a <x:ref>Content-Length</x:ref> header field is present in the
334        response, its value &MUST; match the actual number of octets
335        transmitted in the message body.
336    </t>
337    <t>
338        Date
339    </t>
340    <t>
341        <x:ref>Cache-Control</x:ref>, <x:ref>ETag</x:ref>,
342        <x:ref>Expires</x:ref>, <x:ref>Content-Location</x:ref> and/or
343        <x:ref>Vary</x:ref>, if the header field would have been sent in a
344        <x:ref>200 (OK)</x:ref> response to the same request
345    </t>
346  </list>
347</t>
348<t>
349   If a 206 is sent in response to a request with an <x:ref>If-Range</x:ref>
350   header field, it &SHOULD-NOT; include other representation header fields.
351   Otherwise, the response &MUST; include all of the representation header
352   fields that would have been returned with a <x:ref>200 (OK)</x:ref> response
353   to the same request.
354</t>
355<t>
356   Caches &MAY; use a heuristic (see &p6-heuristic;) to determine
357   freshness for 206 responses.
358</t>
359</section>
360
361<section title="416 Requested Range Not Satisfiable" anchor="status.416">
362  <iref primary="true" item="416 Requested Range Not Satisfiable (status code)" x:for-anchor=""/>
363  <iref primary="true" item="Status Codes" subitem="416 Requested Range Not Satisfiable" x:for-anchor=""/>
364  <x:anchor-alias value="416 (Requested Range Not Satisfiable)"/>
365<t>
366   A server &SHOULD; return a response with this status code if a request
367   included a <x:ref>Range</x:ref> header field (<xref target="header.range"/>),
368   and none of the ranges-specifier values in this field overlap the current
369   extent of the selected resource, and the request did not include an
370   <x:ref>If-Range</x:ref> header field (<xref target="header.if-range"/>).
371   (For byte-ranges, this means that the first-byte-pos of all of the
372   byte-range-spec values were greater than the current length of the selected
373   resource.)
374</t>
375<t>
376   When this status code is returned for a byte-range request, the
377   response &SHOULD; include a <x:ref>Content-Range</x:ref> header field
378   specifying the current length of the representation (see <xref target="header.content-range"/>).
379   This response &MUST-NOT; use the multipart/byteranges content-type. For example,
380</t>
381<figure><artwork type="message/http; msgtype=&#34;response&#34;" x:indent-with="  ">
382HTTP/1.1 416 Requested Range Not Satisfiable
383Date: Mon, 20 Jan 2012 15:41:54 GMT
384Content-Range: bytes */47022
385Content-Type: image/gif
386</artwork></figure>
387<x:note>
388  <t>
389    &Note; Clients cannot depend on servers to send a <x:ref>416 (Requested
390    Range Not Satisfiable)</x:ref> response instead of a <x:ref>200 (OK)</x:ref>
391    response for an unsatisfiable <x:ref>Range</x:ref> header field, since not
392    all servers implement this header field.
393  </t>
394</x:note>
395</section>
396</section>
397
398<section title="Responses to a Range Request">
399<section title="Response to a Single and Multiple Ranges Request">
400<t>
401   When an HTTP message includes the content of a single range (for
402   example, a response to a request for a single range, or to a request
403   for a set of ranges that overlap without any holes), this content is
404   transmitted with a <x:ref>Content-Range</x:ref> header field, and a
405   <x:ref>Content-Length</x:ref> header field showing the number of bytes
406   actually transferred. For example,
407</t>
408<figure><artwork type="message/http; msgtype=&#34;response&#34;" x:indent-with="  ">
409HTTP/1.1 206 Partial Content
410Date: Wed, 15 Nov 1995 06:25:24 GMT
411Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
412Content-Range: bytes 21010-47021/47022
413Content-Length: 26012
414Content-Type: image/gif
415</artwork></figure>
416<t>
417   When an HTTP message includes the content of multiple ranges (for
418   example, a response to a request for multiple non-overlapping
419   ranges), these are transmitted as a multipart message. The multipart
420   media type used for this purpose is "multipart/byteranges" as defined
421   in <xref target="internet.media.type.multipart.byteranges"/>.
422</t>
423<t>
424   A server &MAY; combine requested ranges when those ranges are overlapping
425   (see <xref target="overlapping.ranges"/>).
426</t>
427<t>
428   A response to a request for a single range &MUST-NOT; be sent using the
429   multipart/byteranges media type.  A response to a request for
430   multiple ranges, whose result is a single range, &MAY; be sent as a
431   multipart/byteranges media type with one part. A client that cannot
432   decode a multipart/byteranges message &MUST-NOT; ask for multiple
433   ranges in a single request.
434</t>
435<t>
436   When a client asks for multiple ranges in one request, the
437   server &SHOULD; return them in the order that they appeared in the
438   request.
439</t>
440</section>
441
442<section title="Combining Ranges" anchor="combining.byte.ranges">
443<t>
444   A response might transfer only a subrange of a representation if the
445   connection closed prematurely or if the request used one or more Range
446   specifications.  After several such transfers, a client might have
447   received several ranges of the same representation.  These ranges can only
448   be safely combined if they all have in common the same strong validator,
449   where "strong validator" is defined to be either an entity-tag that is
450   not marked as weak (&entity-tags;) or, if no entity-tag is provided, a
451   <x:ref>Last-Modified</x:ref> value that is strong in the sense defined by
452   &lastmod-comparison;.
453</t>
454<t>
455   When a client receives an incomplete <x:ref>200 (OK)</x:ref> or <x:ref>206 (Partial Content)</x:ref>
456   response and already has one or more stored responses for the same method
457   and effective request URI, all of the stored responses with the same
458   strong validator &MAY; be combined with the partial content in this new
459   response.  If none of the stored responses contain the same strong
460   validator, then this new response corresponds to a new representation
461   and &MUST-NOT; be combined with the existing stored responses.
462</t>
463<t>
464   If the new response is an incomplete <x:ref>200 (OK)</x:ref> response, then the header
465   fields of that new response are used for any combined response and replace
466   those of the matching stored responses.
467</t>
468<t>
469   If the new response is a <x:ref>206 (Partial Content)</x:ref> response and at least one
470   of the matching stored responses is a <x:ref>200 (OK)</x:ref>, then the combined response
471   header fields consist of the most recent 200 response's header fields.
472   If all of the matching stored responses are 206 responses, then the
473   stored response with the most header fields is used as the source of
474   header fields for the combined response, except that the client &MUST;
475   use other header fields provided in the new response, aside from
476   <x:ref>Content-Range</x:ref>, to replace all instances of the corresponding
477   header fields in the stored response.
478</t>
479<t>
480   The combined response message body consists of the union of partial
481   content ranges in the new response and each of the selected responses.
482   If the union consists of the entire range of the representation, then the
483   combined response &MUST; be recorded as a complete <x:ref>200 (OK)</x:ref>
484   response with a <x:ref>Content-Length</x:ref> header field that reflects the
485   complete length. Otherwise, the combined response(s) &MUST; include a
486   <x:ref>Content-Range</x:ref> header field describing the included range(s)
487   and be recorded as incomplete.  If the union consists of a discontinuous
488   range of the representation, then the client &MAY; store it as either a
489   multipart range response or as multiple <x:ref>206</x:ref> responses with
490   one continuous range each.
491</t>
492</section>
493</section>
494
495<section title="Header Field Definitions" anchor="header.field.definitions">
496<t>
497   This section defines the syntax and semantics of HTTP/1.1 header fields
498   related to range requests and partial responses.
499</t>
500
501<section title="Accept-Ranges" anchor="header.accept-ranges">
502  <iref primary="true" item="Accept-Ranges header field" x:for-anchor=""/>
503  <iref primary="true" item="Header Fields" subitem="Accept-Ranges" x:for-anchor=""/>
504  <x:anchor-alias value="Accept-Ranges"/>
505  <x:anchor-alias value="acceptable-ranges"/>
506<t>
507   The "Accept-Ranges" header field allows a resource to indicate
508   its acceptance of range requests.
509</t>
510<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Ranges"/><iref primary="true" item="Grammar" subitem="acceptable-ranges"/>
511  <x:ref>Accept-Ranges</x:ref>     = <x:ref>acceptable-ranges</x:ref>
512  <x:ref>acceptable-ranges</x:ref> = 1#<x:ref>range-unit</x:ref> / "none"
513</artwork></figure>
514<t>
515      Origin servers that accept byte-range requests &MAY; send
516</t>
517<figure><artwork type="example">
518  Accept-Ranges: bytes
519</artwork></figure>
520<t>
521      but are not required to do so. Clients &MAY; generate range
522      requests without having received this header field for the resource
523      involved. Range units are defined in <xref target="range.units"/>.
524</t>
525<t>
526      Servers that do not accept any kind of range request for a
527      resource &MAY; send
528</t>
529<figure><artwork type="example">
530  Accept-Ranges: none
531</artwork></figure>
532<t>
533      to advise the client not to attempt a range request.
534</t>
535</section>
536
537<section title="Content-Range" anchor="header.content-range">
538  <iref primary="true" item="Content-Range header field" x:for-anchor=""/>
539  <iref primary="true" item="Header Fields" subitem="Content-Range" x:for-anchor=""/>
540  <x:anchor-alias value="byte-content-range-spec"/>
541  <x:anchor-alias value="byte-range-resp-spec"/>
542  <x:anchor-alias value="Content-Range"/>
543  <x:anchor-alias value="instance-length"/>
544  <x:anchor-alias value="other-content-range-spec"/>
545  <x:anchor-alias value="other-range-resp-spec"/>
546<t>
547   The "Content-Range" header field is sent with a partial representation to
548   specify where in the full representation the payload body is intended to be
549   applied.
550</t>
551<t>   
552   Range units are defined in <xref target="range.units"/>.
553</t>
554<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"/>
555  <x:ref>Content-Range</x:ref>           = <x:ref>byte-content-range-spec</x:ref>
556                          / <x:ref>other-content-range-spec</x:ref>
557                         
558  <x:ref>byte-content-range-spec</x:ref> = <x:ref>bytes-unit</x:ref> <x:ref>SP</x:ref>
559                            <x:ref>byte-range-resp-spec</x:ref> "/"
560                            ( <x:ref>instance-length</x:ref> / "*" )
561 
562  <x:ref>byte-range-resp-spec</x:ref>    = (<x:ref>first-byte-pos</x:ref> "-" <x:ref>last-byte-pos</x:ref>)
563                          / "*"
564                         
565  <x:ref>instance-length</x:ref>         = 1*<x:ref>DIGIT</x:ref>
566 
567  <x:ref>other-content-range-spec</x:ref> = <x:ref>other-range-unit</x:ref> <x:ref>SP</x:ref>
568                             <x:ref>other-range-resp-spec</x:ref>
569  <x:ref>other-range-resp-spec</x:ref>    = *<x:ref>CHAR</x:ref>
570</artwork></figure>
571<t>
572   The header field &SHOULD; indicate the total length of the full representation,
573   unless this length is unknown or difficult to determine. The asterisk
574   "*" character means that the instance-length is unknown at the time
575   when the response was generated.
576</t>
577<t>
578   Unlike byte-ranges-specifier values (see <xref target="byte.ranges"/>), a byte-range-resp-spec
579   &MUST; only specify one range, and &MUST; contain
580   absolute byte positions for both the first and last byte of the
581   range.
582</t>
583<t>
584   A byte-content-range-spec with a byte-range-resp-spec whose last-byte-pos
585   value is less than its first-byte-pos value, or whose
586   instance-length value is less than or equal to its last-byte-pos
587   value, is invalid. The recipient of an invalid byte-content-range-spec
588   &MUST; ignore it and any content transferred along with it.
589</t>
590<t>
591   In the case of a byte range request:
592   A server sending a response with status code <x:ref>416 (Requested Range Not
593   Satisfiable)</x:ref> &SHOULD; include a Content-Range field with a byte-range-resp-spec
594   of "*". The instance-length specifies the current length of
595   the selected resource. A response with status code <x:ref>206 (Partial Content)</x:ref>
596   &MUST-NOT; include a Content-Range field with a byte-range-resp-spec of "*".
597</t>
598<t>
599  The "Content-Range" header field has no meaning for status codes that do not
600  explicitly describe its semantic. Currently, only status codes
601  <x:ref>206 (Partial Content)</x:ref> and <x:ref>416 (Requested Range Not Satisfiable)</x:ref> describe
602  the meaning of this header field.
603</t>
604<t>
605   Examples of byte-content-range-spec values, assuming that the representation
606   contains a total of 1234 bytes:
607   <list style="symbols">
608      <t>
609        The first 500 bytes:
610<figure><artwork type="example" x:indent-with="   ">
611  bytes 0-499/1234
612</artwork></figure>
613      </t>   
614      <t>
615        The second 500 bytes:
616<figure><artwork type="example" x:indent-with="   ">
617  bytes 500-999/1234
618</artwork></figure>
619      </t>   
620      <t>
621        All except for the first 500 bytes:
622<figure><artwork type="example" x:indent-with="   ">
623  bytes 500-1233/1234
624</artwork></figure>
625      </t>   
626      <t>
627        The last 500 bytes:
628<figure><artwork type="example" x:indent-with="   ">
629  bytes 734-1233/1234
630</artwork></figure>
631      </t>   
632   </list>
633</t>
634<t>
635   If the server ignores a byte-range-spec (for example if it is
636   syntactically invalid, or if it might be seen as a denial-of-service
637   attack), the server &SHOULD; treat the request as if the invalid <x:ref>Range</x:ref>
638   header field did not exist. (Normally, this means return a <x:ref>200 (OK)</x:ref>
639   response containing the full representation).
640</t>
641</section>
642
643<section title="If-Range" anchor="header.if-range">
644  <iref primary="true" item="If-Range header field" x:for-anchor=""/>
645  <iref primary="true" item="Header Fields" subitem="If-Range" x:for-anchor=""/>
646  <x:anchor-alias value="If-Range"/>
647<t>
648   If a client has a partial copy of a representation and wishes
649   to have an up-to-date copy of the entire representation, it could use the
650   <x:ref>Range</x:ref> header field with a conditional GET (using
651   either or both of <x:ref>If-Unmodified-Since</x:ref> and
652   <x:ref>If-Match</x:ref>.) However, if the condition fails because the
653   representation has been modified, the client would then have to make a
654   second request to obtain the entire current representation.
655</t>
656<t>
657   The "If-Range" header field allows a client to "short-circuit" the second
658   request. Informally, its meaning is "if the representation is unchanged, send
659   me the part(s) that I am missing; otherwise, send me the entire new
660   representation".
661</t>
662<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="If-Range"/>
663  <x:ref>If-Range</x:ref> = <x:ref>entity-tag</x:ref> / <x:ref>HTTP-date</x:ref>
664</artwork></figure>
665<t>
666   Clients &MUST-NOT; use an entity-tag marked as weak in an If-Range
667   field value and &MUST-NOT; use a <x:ref>Last-Modified</x:ref> date in an
668   If-Range field value unless it has no entity-tag for the representation and
669   the Last-Modified date it does have for the representation is strong
670   in the sense defined by &lastmod-comparison;.
671</t>
672<t>
673   A server that evaluates a conditional range request that is applicable
674   to one of its representations &MUST; evaluate the condition as false if
675   the entity-tag used as a validator is marked as weak or, when an HTTP-date
676   is used as the validator, if the date value is not strong in the sense
677   defined by &lastmod-comparison;. (A server can distinguish between a
678   valid HTTP-date and any form of entity-tag by examining the first
679   two characters.)
680</t>
681<t>
682   The If-Range header field &SHOULD; only be sent by clients together with
683   a Range header field.  The If-Range header field &MUST; be ignored if it
684   is received in a request that does not include a Range header field.
685   The If-Range header field &MUST; be ignored by a server that does not
686   support the sub-range operation.
687</t>
688<t>
689   If the validator given in the If-Range header field matches the current
690   validator for the selected representation of the target resource, then
691   the server &SHOULD; send the specified sub-range of the representation
692   using a <x:ref>206 (Partial Content)</x:ref> response. If the validator does not match,
693   then the server &SHOULD; send the entire representation using a <x:ref>200 (OK)</x:ref>
694   response.
695</t>
696</section>
697
698<section title="Range" anchor="header.range">
699  <iref primary="true" item="Range header field" x:for-anchor=""/>
700  <iref primary="true" item="Header Fields" subitem="Range" x:for-anchor=""/>
701
702<section title="Byte Ranges" anchor="byte.ranges">
703<t>
704   Since all HTTP representations are transferred as sequences
705   of bytes, the concept of a byte range is meaningful for any HTTP
706   representation. (However, not all clients and servers need to support byte-range
707   operations.)
708</t>
709<t>
710   Byte range specifications in HTTP apply to the sequence of bytes in
711   the representation body (not necessarily the same as the message body).
712</t>
713<t anchor="rule.ranges-specifier">
714  <x:anchor-alias value="byte-range-set"/>
715  <x:anchor-alias value="byte-range-spec"/>
716  <x:anchor-alias value="byte-ranges-specifier"/>
717  <x:anchor-alias value="first-byte-pos"/>
718  <x:anchor-alias value="last-byte-pos"/>
719  <x:anchor-alias value="ranges-specifier"/>
720  <x:anchor-alias value="suffix-byte-range-spec"/>
721  <x:anchor-alias value="suffix-length"/>
722
723   A byte range operation &MAY; specify a single range of bytes, or a set
724   of ranges within a single representation.
725</t>
726<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"/>
727  <x:ref>byte-ranges-specifier</x:ref> = <x:ref>bytes-unit</x:ref> "=" <x:ref>byte-range-set</x:ref>
728  <x:ref>byte-range-set</x:ref>  = 1#( <x:ref>byte-range-spec</x:ref> / <x:ref>suffix-byte-range-spec</x:ref> )
729  <x:ref>byte-range-spec</x:ref> = <x:ref>first-byte-pos</x:ref> "-" [ <x:ref>last-byte-pos</x:ref> ]
730  <x:ref>first-byte-pos</x:ref>  = 1*<x:ref>DIGIT</x:ref>
731  <x:ref>last-byte-pos</x:ref>   = 1*<x:ref>DIGIT</x:ref>
732</artwork></figure>
733<t>
734   The first-byte-pos value in a byte-range-spec gives the byte-offset
735   of the first byte in a range. The last-byte-pos value gives the
736   byte-offset of the last byte in the range; that is, the byte
737   positions specified are inclusive. Byte offsets start at zero.
738</t>
739<t>
740   If the last-byte-pos value is present, it &MUST; be greater than or
741   equal to the first-byte-pos in that byte-range-spec, or the byte-range-spec
742   is syntactically invalid. The recipient of a byte-range-set
743   that includes one or more syntactically invalid byte-range-spec
744   values &MUST; ignore the header field that includes that byte-range-set.
745</t>
746<t>
747   If the last-byte-pos value is absent, or if the value is greater than
748   or equal to the current length of the representation body, last-byte-pos is
749   taken to be equal to one less than the current length of the representation
750   in bytes.
751</t>
752<t>
753   By its choice of last-byte-pos, a client can limit the number of
754   bytes retrieved without knowing the size of the representation.
755</t>
756<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="suffix-byte-range-spec"/><iref primary="true" item="Grammar" subitem="suffix-length"/>
757  <x:ref>suffix-byte-range-spec</x:ref> = "-" <x:ref>suffix-length</x:ref>
758  <x:ref>suffix-length</x:ref> = 1*<x:ref>DIGIT</x:ref>
759</artwork></figure>
760<t>
761   A suffix-byte-range-spec is used to specify the suffix of the
762   representation body, of a length given by the suffix-length value. (That is,
763   this form specifies the last N bytes of a representation.) If the
764   representation is shorter than the specified suffix-length, the entire
765   representation is used.
766</t>
767<t>
768   If a syntactically valid byte-range-set includes at least one byte-range-spec
769   whose first-byte-pos is less than the current length of
770   the representation, or at least one suffix-byte-range-spec with a non-zero
771   suffix-length, then the byte-range-set is satisfiable.
772   Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set
773   is unsatisfiable, the server &SHOULD; return a response with a
774   <x:ref>416 (Requested Range Not Satisfiable)</x:ref> status code. Otherwise, the server
775   &SHOULD; return a response with a <x:ref>206 (Partial Content)</x:ref> status code
776   containing the satisfiable ranges of the representation.
777</t>
778<t>
779   Examples of byte-ranges-specifier values (assuming a representation of
780   length 10000):
781  <list style="symbols">
782     <t>The first 500 bytes (byte offsets 0-499, inclusive):
783<figure><artwork type="example" x:indent-with="   ">
784  bytes=0-499
785</artwork></figure>
786    </t>
787     <t>The second 500 bytes (byte offsets 500-999, inclusive):
788<figure><artwork type="example" x:indent-with="   ">
789  bytes=500-999
790</artwork></figure>
791    </t>
792     <t>The final 500 bytes (byte offsets 9500-9999, inclusive):
793<figure><artwork type="example" x:indent-with="   ">
794  bytes=-500
795</artwork></figure>
796    Or:
797<figure><artwork type="example" x:indent-with="   ">
798  bytes=9500-
799</artwork></figure>
800    </t>
801     <t>The first and last bytes only (bytes 0 and 9999):
802<figure><artwork type="example" x:indent-with="   ">
803  bytes=0-0,-1
804</artwork></figure>
805     </t>
806     <t>Several legal but not canonical specifications of the second 500
807        bytes (byte offsets 500-999, inclusive):
808<figure><artwork type="example" x:indent-with="   ">
809  bytes=500-600,601-999
810  bytes=500-700,601-999
811</artwork></figure>
812     </t>
813  </list>
814</t>
815</section>
816
817<section title="Range Retrieval Requests" anchor="range.retrieval.requests">
818  <x:anchor-alias value="Range"/>
819  <x:anchor-alias value="other-ranges-specifier"/>
820  <x:anchor-alias value="other-range-set"/>
821<t>
822   The "Range" header field defines the GET method (conditional or
823   not) to request one or more sub-ranges of the response representation body, instead
824   of the entire representation body.
825</t>
826<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Range"/>
827  <x:ref>Range</x:ref> = <x:ref>byte-ranges-specifier</x:ref> / <x:ref>other-ranges-specifier</x:ref>
828  <x:ref>other-ranges-specifier</x:ref> = <x:ref>other-range-unit</x:ref> "=" <x:ref>other-range-set</x:ref>
829  <x:ref>other-range-set</x:ref> = 1*<x:ref>CHAR</x:ref>
830</artwork></figure>
831<t>
832   A server &MAY; ignore the Range header field. However, origin
833   servers and intermediate caches ought to support byte ranges when
834   possible, since Range supports efficient recovery from partially
835   failed transfers, and supports efficient partial retrieval of large
836   representations.
837</t>
838<t>
839   If the server supports the Range header field and the specified range or
840   ranges are appropriate for the representation:
841  <list style="symbols">
842     <t>The presence of a Range header field in an unconditional GET modifies
843        what is returned if the GET is otherwise successful. In other
844        words, the response carries a status code of <x:ref>206 (Partial Content)</x:ref>
845        instead of <x:ref>200 (OK)</x:ref>.</t>
846
847     <t>The presence of a Range header field in a conditional GET (a request
848        using one or both of <x:ref>If-Modified-Since</x:ref> and
849        <x:ref>If-None-Match</x:ref>, or one or both of
850        <x:ref>If-Unmodified-Since</x:ref> and <x:ref>If-Match</x:ref>) modifies
851        what is returned if the GET is otherwise successful and the
852        condition is true. It does not affect the <x:ref>304 (Not Modified)</x:ref>
853        response returned if the conditional is false.</t>
854  </list>
855</t>
856<t>
857   In some cases, it might be more appropriate to use the If-Range
858   header field (see <xref target="header.if-range"/>) in addition to the Range
859   header field.
860</t>
861<t>
862   If a proxy that supports ranges receives a Range request, forwards
863   the request to an inbound server, and receives an entire representation in
864   reply, it &MAY; only return the requested range to its client.
865</t>
866</section>
867</section>
868</section>
869
870<section title="IANA Considerations" anchor="IANA.considerations">
871
872<section title="Status Code Registration" anchor="status.code.registration">
873<t>
874   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
875   shall be updated with the registrations below:
876</t>
877<?BEGININC p5-range.iana-status-codes ?>
878<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
879<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
880   <ttcol>Value</ttcol>
881   <ttcol>Description</ttcol>
882   <ttcol>Reference</ttcol>
883   <c>206</c>
884   <c>Partial Content</c>
885   <c>
886      <xref target="status.206"/>
887   </c>
888   <c>416</c>
889   <c>Requested Range Not Satisfiable</c>
890   <c>
891      <xref target="status.416"/>
892   </c>
893</texttable>
894<!--(END)-->
895<?ENDINC p5-range.iana-status-codes ?>
896</section>
897
898<section title="Header Field Registration" anchor="header.field.registration">
899<t>
900   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
901   with the permanent registrations below (see <xref target="RFC3864"/>):
902</t>
903<?BEGININC p5-range.iana-headers ?>
904<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
905<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
906   <ttcol>Header Field Name</ttcol>
907   <ttcol>Protocol</ttcol>
908   <ttcol>Status</ttcol>
909   <ttcol>Reference</ttcol>
910
911   <c>Accept-Ranges</c>
912   <c>http</c>
913   <c>standard</c>
914   <c>
915      <xref target="header.accept-ranges"/>
916   </c>
917   <c>Content-Range</c>
918   <c>http</c>
919   <c>standard</c>
920   <c>
921      <xref target="header.content-range"/>
922   </c>
923   <c>If-Range</c>
924   <c>http</c>
925   <c>standard</c>
926   <c>
927      <xref target="header.if-range"/>
928   </c>
929   <c>Range</c>
930   <c>http</c>
931   <c>standard</c>
932   <c>
933      <xref target="header.range"/>
934   </c>
935</texttable>
936<!--(END)-->
937<?ENDINC p5-range.iana-headers ?>
938<t>
939   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
940</t>
941</section>
942
943<section title="Range Specifier Registration" anchor="range.specifier.registration">
944<t>
945  The registration procedure for HTTP Range Specifiers is defined by
946  <xref target="range.specifier.registry"/> of this document.
947</t>
948<t>
949   The HTTP Range Specifier Registry shall be created at <eref target="http://www.iana.org/assignments/http-range-specifiers"/>
950   and be populated with the registrations below:
951</t>
952<texttable align="left" suppress-title="true" anchor="iana.range.specifiers.table">
953   <ttcol>Range Specifier Name</ttcol>
954   <ttcol>Description</ttcol>
955   <ttcol>Reference</ttcol>
956
957   <c>bytes</c>
958   <c>a range of octets</c>
959   <c><xref target="range.units"/></c>
960
961   <c>none</c>
962   <c>reserved as keyword, indicating no ranges are supported</c>
963   <c><xref target="header.accept-ranges"/></c>
964</texttable>
965<t>
966   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
967</t>
968</section>
969</section>
970
971<section title="Security Considerations" anchor="security.considerations">
972<t>
973   This section is meant to inform application developers, information
974   providers, and users of the security limitations in HTTP/1.1 as
975   described by this document. The discussion does not include
976   definitive solutions to the problems revealed, though it does make
977   some suggestions for reducing security risks.
978</t>
979<section title="Overlapping Ranges" anchor="overlapping.ranges">
980<t>
981   Range requests containing overlapping ranges can lead to the situation
982   where a server is sending far more data than the size of the complete
983   resource representation.
984</t>
985</section>
986</section>
987
988<section title="Acknowledgments" anchor="acks">
989<t>
990  See &acks;.
991</t>
992</section>
993</middle>
994<back>
995
996<references title="Normative References">
997
998<reference anchor="Part1">
999  <front>
1000    <title>HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1001    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1002      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1003      <address><email>fielding@gbiv.com</email></address>
1004    </author>
1005    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1006      <organization abbrev="W3C">World Wide Web Consortium</organization>
1007      <address><email>ylafon@w3.org</email></address>
1008    </author>
1009    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1010      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1011      <address><email>julian.reschke@greenbytes.de</email></address>
1012    </author>
1013    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1014  </front>
1015  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1016  <x:source href="p1-messaging.xml" basename="p1-messaging">
1017    <x:defines>Content-Length</x:defines>
1018  </x:source>
1019</reference>
1020
1021<reference anchor="Part2">
1022  <front>
1023    <title>HTTP/1.1, part 2: Message Semantics, Payload and Content Negotiation</title>
1024    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1025      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1026      <address><email>fielding@gbiv.com</email></address>
1027    </author>
1028    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1029      <organization abbrev="W3C">World Wide Web Consortium</organization>
1030      <address><email>ylafon@w3.org</email></address>
1031    </author>
1032    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1033      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1034      <address><email>julian.reschke@greenbytes.de</email></address>
1035    </author>
1036    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1037  </front>
1038  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1039  <x:source href="p2-semantics.xml" basename="p2-semantics">
1040    <x:defines>200 (OK)</x:defines>
1041    <x:defines>410 (Gone)</x:defines>
1042    <x:defines>Content-Location</x:defines>
1043    <x:defines>Content-Type</x:defines>
1044    <x:defines>Location</x:defines>
1045  </x:source>
1046</reference>
1047
1048<reference anchor="Part4">
1049  <front>
1050    <title>HTTP/1.1, part 4: Conditional Requests</title>
1051    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1052      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1053      <address><email>fielding@gbiv.com</email></address>
1054    </author>
1055    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1056      <organization abbrev="W3C">World Wide Web Consortium</organization>
1057      <address><email>ylafon@w3.org</email></address>
1058    </author>
1059    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1060      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1061      <address><email>julian.reschke@greenbytes.de</email></address>
1062    </author>
1063    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1064  </front>
1065  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1066  <x:source href="p4-conditional.xml" basename="p4-conditional">
1067    <x:defines>304 (Not Modified)</x:defines>
1068    <x:defines>ETag</x:defines>
1069    <x:defines>If-Match</x:defines>
1070    <x:defines>If-Modified-Since</x:defines>
1071    <x:defines>If-None-Match</x:defines>
1072    <x:defines>If-Unmodified-Since</x:defines>
1073    <x:defines>Last-Modified</x:defines>
1074  </x:source>
1075</reference>
1076
1077<reference anchor="Part6">
1078  <front>
1079    <title>HTTP/1.1, part 6: Caching</title>
1080    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1081      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1082      <address><email>fielding@gbiv.com</email></address>
1083    </author>
1084    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1085      <organization abbrev="W3C">World Wide Web Consortium</organization>
1086      <address><email>ylafon@w3.org</email></address>
1087    </author>
1088    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1089      <organization>Rackspace</organization>
1090      <address><email>mnot@mnot.net</email></address>
1091    </author>
1092    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1093      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1094      <address><email>julian.reschke@greenbytes.de</email></address>
1095    </author>
1096    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1097  </front>
1098  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1099  <x:source href="p6-cache.xml" basename="p6-cache">
1100    <x:defines>Cache-Control</x:defines>
1101    <x:defines>Expires</x:defines>
1102    <x:defines>Vary</x:defines>
1103  </x:source>
1104</reference>
1105
1106<reference anchor="RFC2046">
1107  <front>
1108    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1109    <author initials="N." surname="Freed" fullname="Ned Freed">
1110      <organization>Innosoft International, Inc.</organization>
1111      <address><email>ned@innosoft.com</email></address>
1112    </author>
1113    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1114      <organization>First Virtual Holdings</organization>
1115      <address><email>nsb@nsb.fv.com</email></address>
1116    </author>
1117    <date month="November" year="1996"/>
1118  </front>
1119  <seriesInfo name="RFC" value="2046"/>
1120</reference>
1121
1122<reference anchor="RFC2119">
1123  <front>
1124    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1125    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1126      <organization>Harvard University</organization>
1127      <address><email>sob@harvard.edu</email></address>
1128    </author>
1129    <date month="March" year="1997"/>
1130  </front>
1131  <seriesInfo name="BCP" value="14"/>
1132  <seriesInfo name="RFC" value="2119"/>
1133</reference>
1134
1135<reference anchor="RFC5234">
1136  <front>
1137    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1138    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1139      <organization>Brandenburg InternetWorking</organization>
1140      <address>
1141        <email>dcrocker@bbiw.net</email>
1142      </address> 
1143    </author>
1144    <author initials="P." surname="Overell" fullname="Paul Overell">
1145      <organization>THUS plc.</organization>
1146      <address>
1147        <email>paul.overell@thus.net</email>
1148      </address>
1149    </author>
1150    <date month="January" year="2008"/>
1151  </front>
1152  <seriesInfo name="STD" value="68"/>
1153  <seriesInfo name="RFC" value="5234"/>
1154</reference>
1155
1156</references>
1157
1158<references title="Informative References">
1159
1160<reference anchor="RFC2616">
1161  <front>
1162    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
1163    <author initials="R." surname="Fielding" fullname="R. Fielding">
1164      <organization>University of California, Irvine</organization>
1165      <address><email>fielding@ics.uci.edu</email></address>
1166    </author>
1167    <author initials="J." surname="Gettys" fullname="J. Gettys">
1168      <organization>W3C</organization>
1169      <address><email>jg@w3.org</email></address>
1170    </author>
1171    <author initials="J." surname="Mogul" fullname="J. Mogul">
1172      <organization>Compaq Computer Corporation</organization>
1173      <address><email>mogul@wrl.dec.com</email></address>
1174    </author>
1175    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
1176      <organization>MIT Laboratory for Computer Science</organization>
1177      <address><email>frystyk@w3.org</email></address>
1178    </author>
1179    <author initials="L." surname="Masinter" fullname="L. Masinter">
1180      <organization>Xerox Corporation</organization>
1181      <address><email>masinter@parc.xerox.com</email></address>
1182    </author>
1183    <author initials="P." surname="Leach" fullname="P. Leach">
1184      <organization>Microsoft Corporation</organization>
1185      <address><email>paulle@microsoft.com</email></address>
1186    </author>
1187    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
1188      <organization>W3C</organization>
1189      <address><email>timbl@w3.org</email></address>
1190    </author>
1191    <date month="June" year="1999"/>
1192  </front>
1193  <seriesInfo name="RFC" value="2616"/>
1194</reference>
1195
1196<reference anchor='RFC3864'>
1197  <front>
1198    <title>Registration Procedures for Message Header Fields</title>
1199    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
1200      <organization>Nine by Nine</organization>
1201      <address><email>GK-IETF@ninebynine.org</email></address>
1202    </author>
1203    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
1204      <organization>BEA Systems</organization>
1205      <address><email>mnot@pobox.com</email></address>
1206    </author>
1207    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
1208      <organization>HP Labs</organization>
1209      <address><email>JeffMogul@acm.org</email></address>
1210    </author>
1211    <date year='2004' month='September' />
1212  </front>
1213  <seriesInfo name='BCP' value='90' />
1214  <seriesInfo name='RFC' value='3864' />
1215</reference>
1216
1217<reference anchor="RFC4288">
1218  <front>
1219    <title>Media Type Specifications and Registration Procedures</title>
1220    <author initials="N." surname="Freed" fullname="N. Freed">
1221      <organization>Sun Microsystems</organization>
1222      <address>
1223        <email>ned.freed@mrochek.com</email>
1224      </address>
1225    </author>
1226    <author initials="J." surname="Klensin" fullname="J. Klensin">
1227      <address>
1228        <email>klensin+ietf@jck.com</email>
1229      </address>
1230    </author>
1231    <date year="2005" month="December"/>
1232  </front>
1233  <seriesInfo name="BCP" value="13"/>
1234  <seriesInfo name="RFC" value="4288"/>
1235</reference>
1236
1237<reference anchor='RFC5226'>
1238  <front>
1239    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1240    <author initials='T.' surname='Narten' fullname='T. Narten'>
1241      <organization>IBM</organization>
1242      <address><email>narten@us.ibm.com</email></address>
1243    </author>
1244    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1245      <organization>Google</organization>
1246      <address><email>Harald@Alvestrand.no</email></address>
1247    </author>
1248    <date year='2008' month='May' />
1249  </front>
1250  <seriesInfo name='BCP' value='26' />
1251  <seriesInfo name='RFC' value='5226' />
1252</reference>
1253
1254</references>
1255
1256<section title="Internet Media Type multipart/byteranges" anchor="internet.media.type.multipart.byteranges">
1257<iref item="Media Type" subitem="multipart/byteranges" primary="true"/>
1258<iref item="multipart/byteranges Media Type" primary="true"/>
1259<t>
1260   When an HTTP <x:ref>206 (Partial Content)</x:ref> response message includes the
1261   content of multiple ranges (a response to a request for multiple
1262   non-overlapping ranges), these are transmitted as a multipart
1263   message body (<xref target="RFC2046" x:fmt="," x:sec="5.1"/>). The media type for this purpose is called
1264   "multipart/byteranges".  The following is to be registered with IANA <xref target="RFC4288"/>.
1265</t>
1266<x:note>
1267  <t>
1268    &Note; Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1269  </t>
1270</x:note>
1271<t>
1272   The multipart/byteranges media type includes one or more parts, each
1273   with its own <x:ref>Content-Type</x:ref> and <x:ref>Content-Range</x:ref>
1274   fields. The required boundary parameter specifies the boundary string used
1275   to separate each body-part.
1276</t>
1277<t>
1278  <list style="hanging" x:indent="12em">
1279    <t hangText="Type name:">
1280      multipart
1281    </t>
1282    <t hangText="Subtype name:">
1283      byteranges
1284    </t>
1285    <t hangText="Required parameters:">
1286      boundary
1287    </t>
1288    <t hangText="Optional parameters:">
1289      none
1290    </t>
1291    <t hangText="Encoding considerations:">
1292      only "7bit", "8bit", or "binary" are permitted
1293    </t>
1294    <t hangText="Security considerations:">
1295      none
1296    </t>
1297    <t hangText="Interoperability considerations:">
1298      none
1299    </t>
1300    <t hangText="Published specification:">
1301      This specification (see <xref target="internet.media.type.multipart.byteranges"/>).
1302    </t>
1303    <t hangText="Applications that use this media type:">
1304    </t>
1305    <t hangText="Additional information:">
1306      <list style="hanging">
1307        <t hangText="Magic number(s):">none</t>
1308        <t hangText="File extension(s):">none</t>
1309        <t hangText="Macintosh file type code(s):">none</t>
1310      </list>
1311    </t>
1312    <t hangText="Person and email address to contact for further information:">
1313      See Authors Section.
1314    </t>
1315    <t hangText="Intended usage:">
1316      COMMON
1317    </t>
1318    <t hangText="Restrictions on usage:">
1319      none
1320    </t>
1321    <t hangText="Author/Change controller:">
1322      IESG
1323    </t>
1324  </list>
1325</t>
1326<figure><preamble>
1327   For example:
1328</preamble><artwork type="example">
1329  HTTP/1.1 206 Partial Content
1330  Date: Wed, 15 Nov 1995 06:25:24 GMT
1331  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1332  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1333 
1334  --THIS_STRING_SEPARATES
1335  Content-type: application/pdf
1336  Content-range: bytes 500-999/8000
1337 
1338  ...the first range...
1339  --THIS_STRING_SEPARATES
1340  Content-type: application/pdf
1341  Content-range: bytes 7000-7999/8000
1342 
1343  ...the second range
1344  --THIS_STRING_SEPARATES--
1345</artwork></figure>
1346<figure><preamble>
1347   Other example:
1348</preamble>
1349<artwork type="example">
1350  HTTP/1.1 206 Partial Content
1351  Date: Tue, 14 Nov 1995 06:25:24 GMT
1352  Last-Modified: Tue, 14 July 04:58:08 GMT
1353  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1354 
1355  --THIS_STRING_SEPARATES
1356  Content-type: video/example
1357  Content-range: exampleunit 1.2-4.3/25
1358 
1359  ...the first range...
1360  --THIS_STRING_SEPARATES
1361  Content-type: video/example
1362  Content-range: exampleunit 11.2-14.3/25
1363 
1364  ...the second range
1365  --THIS_STRING_SEPARATES--
1366</artwork>
1367</figure>
1368<t>
1369      Notes:
1370  <list style="numbers">
1371      <t>Additional CRLFs &MAY; precede the first boundary string in the body.</t>
1372
1373      <t>Although <xref target="RFC2046"/> permits the boundary string to be
1374         quoted, some existing implementations handle a quoted boundary
1375         string incorrectly.</t>
1376
1377      <t>A number of clients and servers were coded to an early draft
1378         of the byteranges specification to use a media type of
1379         multipart/x-byteranges<iref item="multipart/x-byteranges Media Type"/><iref item="Media Type" subitem="multipart/x-byteranges"/>, which is almost, but not quite
1380         compatible with the version documented in HTTP/1.1.</t>
1381  </list>
1382</t>
1383</section>
1384
1385<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
1386<t>
1387  Clarify that it is not ok to use a weak validator in a <x:ref>206</x:ref> response.
1388  (<xref target="status.206"/>)
1389</t>
1390<t>
1391  Change ABNF productions for header fields to only define the field value.
1392  (<xref target="header.field.definitions"/>)
1393</t>
1394<t>
1395  Clarify that multipart/byteranges can consist of a single part.
1396  (<xref target="internet.media.type.multipart.byteranges"/>)
1397</t>
1398</section>
1399
1400<?BEGININC p5-range.abnf-appendix ?>
1401<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1402<figure>
1403<artwork type="abnf" name="p5-range.parsed-abnf">
1404<x:ref>Accept-Ranges</x:ref> = acceptable-ranges
1405
1406<x:ref>Content-Range</x:ref> = byte-content-range-spec / other-content-range-spec
1407
1408<x:ref>HTTP-date</x:ref> = &lt;HTTP-date, defined in [Part2], Section 5.1&gt;
1409
1410<x:ref>If-Range</x:ref> = entity-tag / HTTP-date
1411
1412<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 3.2.1&gt;
1413
1414<x:ref>Range</x:ref> = byte-ranges-specifier / other-ranges-specifier
1415
1416<x:ref>acceptable-ranges</x:ref> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1417 range-unit ] ) ) / "none"
1418
1419<x:ref>byte-content-range-spec</x:ref> = bytes-unit SP byte-range-resp-spec "/" (
1420 instance-length / "*" )
1421<x:ref>byte-range-resp-spec</x:ref> = ( first-byte-pos "-" last-byte-pos ) / "*"
1422<x:ref>byte-range-set</x:ref> = *( "," OWS ) ( byte-range-spec /
1423 suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
1424 suffix-byte-range-spec ) ] )
1425<x:ref>byte-range-spec</x:ref> = first-byte-pos "-" [ last-byte-pos ]
1426<x:ref>byte-ranges-specifier</x:ref> = bytes-unit "=" byte-range-set
1427<x:ref>bytes-unit</x:ref> = "bytes"
1428
1429<x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in [Part4], Section 2.3&gt;
1430
1431<x:ref>first-byte-pos</x:ref> = 1*DIGIT
1432
1433<x:ref>instance-length</x:ref> = 1*DIGIT
1434
1435<x:ref>last-byte-pos</x:ref> = 1*DIGIT
1436
1437<x:ref>other-content-range-spec</x:ref> = other-range-unit SP other-range-resp-spec
1438<x:ref>other-range-resp-spec</x:ref> = *CHAR
1439<x:ref>other-range-set</x:ref> = 1*CHAR
1440<x:ref>other-range-unit</x:ref> = token
1441<x:ref>other-ranges-specifier</x:ref> = other-range-unit "=" other-range-set
1442
1443<x:ref>range-unit</x:ref> = bytes-unit / other-range-unit
1444
1445<x:ref>suffix-byte-range-spec</x:ref> = "-" suffix-length
1446<x:ref>suffix-length</x:ref> = 1*DIGIT
1447
1448<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.4&gt;
1449</artwork>
1450</figure>
1451<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
1452; Accept-Ranges defined but not used
1453; Content-Range defined but not used
1454; If-Range defined but not used
1455; Range defined but not used
1456</artwork></figure></section>
1457<?ENDINC p5-range.abnf-appendix ?>
1458
1459
1460<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
1461
1462<section title="Since RFC 2616">
1463<t>
1464  Extracted relevant partitions from <xref target="RFC2616"/>.
1465</t>
1466</section>
1467
1468<section title="Since draft-ietf-httpbis-p5-range-00">
1469<t>
1470  Closed issues:
1471  <list style="symbols"> 
1472    <t>
1473      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/18"/>:
1474      "Cache validators in 206 responses"
1475      (<eref target="http://purl.org/NET/http-errata#ifrange206"/>)
1476    </t>
1477    <t>
1478      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
1479      "Normative and Informative references"
1480    </t>
1481    <t>
1482      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
1483      "Normative up-to-date references"
1484    </t>
1485  </list>
1486</t>
1487</section>
1488
1489<section title="Since draft-ietf-httpbis-p5-range-01">
1490<t>
1491  Closed issues:
1492  <list style="symbols"> 
1493    <t>
1494      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
1495      "Updating to RFC4288"
1496    </t>
1497  </list>
1498</t>
1499<t>
1500  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1501  <list style="symbols"> 
1502    <t>
1503      Add explicit references to BNF syntax and rules imported from other parts of the specification.
1504    </t>
1505  </list>
1506</t>
1507</section>
1508
1509<section title="Since draft-ietf-httpbis-p5-range-02" anchor="changes.since.02">
1510<t>
1511  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
1512  <list style="symbols"> 
1513    <t>
1514      Reference RFC 3984, and update header field registrations for headers defined
1515      in this document.
1516    </t>
1517  </list>
1518</t>
1519</section>
1520
1521<section title="Since draft-ietf-httpbis-p5-range-03" anchor="changes.since.03">
1522<t>
1523  None.
1524</t>
1525</section>
1526
1527<section title="Since draft-ietf-httpbis-p5-range-04" anchor="changes.since.04">
1528<t>
1529  Closed issues:
1530  <list style="symbols"> 
1531    <t>
1532      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/133"/>:
1533      "multipart/byteranges minimum number of parts"
1534    </t>
1535  </list>
1536</t>
1537<t>
1538  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1539  <list style="symbols"> 
1540    <t>
1541      Use "/" instead of "|" for alternatives.
1542    </t>
1543    <t>
1544      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
1545      whitespace ("OWS") and required whitespace ("RWS").
1546    </t>
1547    <t>
1548      Rewrite ABNFs to spell out whitespace rules, factor out
1549      header field value format definitions.
1550    </t>
1551  </list>
1552</t>
1553</section>
1554
1555<section title="Since draft-ietf-httpbis-p5-range-05" anchor="changes.since.05">
1556<t>
1557  Closed issues:
1558  <list style="symbols"> 
1559    <t>
1560      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/142"/>:
1561      "State base for *-byte-pos and suffix-length"
1562    </t>
1563  </list>
1564</t>
1565<t>
1566  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1567  <list style="symbols"> 
1568    <t>
1569      Remove bias in favor of byte ranges; allow custom ranges in ABNF.
1570    </t>
1571  </list>
1572</t>
1573<t>
1574  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1575  <list style="symbols"> 
1576    <t>
1577      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
1578    </t>
1579  </list>
1580</t>
1581</section>
1582
1583<section title="Since draft-ietf-httpbis-p5-range-06" anchor="changes.since.06">
1584<t>
1585  Closed issues:
1586  <list style="symbols"> 
1587    <t>
1588      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/161"/>:
1589      "base for numeric protocol elements"
1590    </t>
1591  </list>
1592</t>
1593</section>
1594
1595<section title="Since draft-ietf-httpbis-p5-range-07" anchor="changes.since.07">
1596<t>
1597  Closed issues:
1598  <list style="symbols">
1599    <t>
1600      Fixed discrepancy in the If-Range definition about allowed validators.
1601    </t>
1602    <t>
1603      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/150" />: "multipart/byteranges for custom range units"
1604    </t>
1605    <t>
1606      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/151" />: "range unit missing from other-ranges-specifier in Range header"
1607    </t>
1608    <t>
1609      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/198"/>:
1610      "move IANA registrations for optional status codes"
1611    </t>
1612  </list>
1613</t>
1614</section>
1615
1616<section title="Since draft-ietf-httpbis-p5-range-08" anchor="changes.since.08">
1617<t>
1618  No significant changes.
1619</t>
1620</section>
1621
1622<section title="Since draft-ietf-httpbis-p5-range-09" anchor="changes.since.09">
1623<t>
1624 No significant changes.
1625</t>
1626</section>
1627
1628<section title="Since draft-ietf-httpbis-p5-range-10" anchor="changes.since.10">
1629<t>
1630  Closed issues:
1631  <list style="symbols"> 
1632    <t>
1633      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
1634      "Clarify 'Requested Variant'"
1635    </t>
1636    <t>
1637      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
1638      "Clarify entity / representation / variant terminology"
1639    </t>
1640    <t>
1641      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
1642      "consider removing the 'changes from 2068' sections"
1643    </t>
1644  </list>
1645</t>
1646<t>
1647  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1648  <list style="symbols"> 
1649    <t>
1650      Add IANA registry.
1651    </t>
1652  </list>
1653</t>
1654</section>
1655
1656<section title="Since draft-ietf-httpbis-p5-range-11" anchor="changes.since.11">
1657<t>
1658  Closed issues:
1659  <list style="symbols"> 
1660    <t>
1661      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/217"/>:
1662      "Caches can't be required to serve ranges"
1663    </t>
1664  </list>
1665</t>
1666</section>
1667
1668<section title="Since draft-ietf-httpbis-p5-range-12" anchor="changes.since.12">
1669<t>
1670  Closed issues:
1671  <list style="symbols"> 
1672    <t>
1673      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
1674      "Header Classification"
1675    </t>
1676  </list>
1677</t>
1678</section>
1679
1680<section title="Since draft-ietf-httpbis-p5-range-13" anchor="changes.since.13">
1681<t>
1682  Closed issues:
1683  <list style="symbols">
1684    <t>
1685      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
1686      "untangle ABNFs for header fields"
1687    </t>
1688  </list>
1689</t>
1690</section>
1691
1692<section title="Since draft-ietf-httpbis-p5-range-14" anchor="changes.since.14">
1693<t>
1694  None.
1695</t>
1696</section>
1697
1698<section title="Since draft-ietf-httpbis-p5-range-15" anchor="changes.since.15">
1699<t>
1700  Closed issues:
1701  <list style="symbols">
1702    <t>
1703      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/175"/>:
1704      "Security consideration: range flooding"
1705    </t>
1706  </list>
1707</t>
1708</section>
1709
1710<section title="Since draft-ietf-httpbis-p5-range-16" anchor="changes.since.16">
1711<t>
1712  Closed issues:
1713  <list style="symbols"> 
1714    <t>
1715      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/186"/>:
1716      "Document HTTP's error-handling philosophy"
1717    </t>
1718    <t>
1719      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/301"/>:
1720      "Content-Range on responses other than 206"
1721    </t>
1722    <t>
1723      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/319"/>:
1724      "case sensitivity of ranges in p5"
1725    </t>
1726  </list>
1727</t>
1728</section>
1729
1730<section title="Since draft-ietf-httpbis-p5-range-17" anchor="changes.since.17">
1731<t>
1732  None.
1733</t>
1734</section>
1735
1736<section title="Since draft-ietf-httpbis-p5-range-18" anchor="changes.since.18">
1737<t>
1738  Closed issues:
1739  <list style="symbols"> 
1740    <t>
1741      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/311"/>:
1742      "Add limitations to Range to reduce its use as a denial-of-service tool"
1743    </t>
1744  </list>
1745</t>
1746</section>
1747
1748<section title="Since draft-ietf-httpbis-p5-range-19" anchor="changes.since.19">
1749<t>
1750  Closed issues:
1751  <list style="symbols"> 
1752    <t>
1753      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/358"/>:
1754      "ABNF list expansion code problem"
1755    </t>
1756    <t>
1757      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/361"/>:
1758      "ABNF requirements for recipients"
1759    </t>
1760    <t>
1761      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/367"/>:
1762      "reserve 'none' as byte range unit"
1763    </t>
1764  </list>
1765</t>
1766</section>
1767
1768</section>
1769
1770</back>
1771</rfc>
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