source: draft-ietf-httpbis/latest/p5-range.xml @ 1767

Last change on this file since 1767 was 1767, checked in by julian.reschke@…, 7 years ago

Explain that parsers need to be careful with the values in byte ranges (stealing text from definition of Content-Length) (see #369)

  • Property svn:eol-style set to native
  • Property svn:mime-type set to text/xml
File size: 68.2 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 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   A byte range operation &MAY; specify a single range of bytes, or a set
723   of ranges within a single representation.
724</t>
725<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"/>
726  <x:ref>byte-ranges-specifier</x:ref> = <x:ref>bytes-unit</x:ref> "=" <x:ref>byte-range-set</x:ref>
727  <x:ref>byte-range-set</x:ref>  = 1#( <x:ref>byte-range-spec</x:ref> / <x:ref>suffix-byte-range-spec</x:ref> )
728  <x:ref>byte-range-spec</x:ref> = <x:ref>first-byte-pos</x:ref> "-" [ <x:ref>last-byte-pos</x:ref> ]
729  <x:ref>first-byte-pos</x:ref>  = 1*<x:ref>DIGIT</x:ref>
730  <x:ref>last-byte-pos</x:ref>   = 1*<x:ref>DIGIT</x:ref>
731</artwork></figure>
732<t>
733   The first-byte-pos value in a byte-range-spec gives the byte-offset
734   of the first byte in a range. The last-byte-pos value gives the
735   byte-offset of the last byte in the range; that is, the byte
736   positions specified are inclusive. Byte offsets start at zero.
737</t>
738<t>
739   If the last-byte-pos value is present, it &MUST; be greater than or
740   equal to the first-byte-pos in that byte-range-spec, or the byte-range-spec
741   is syntactically invalid. The recipient of a byte-range-set
742   that includes one or more syntactically invalid byte-range-spec
743   values &MUST; ignore the header field that includes that byte-range-set.
744</t>
745<t>
746   If the last-byte-pos value is absent, or if the value is greater than
747   or equal to the current length of the representation body, last-byte-pos is
748   taken to be equal to one less than the current length of the representation
749   in bytes.
750</t>
751<t>
752   By its choice of last-byte-pos, a client can limit the number of
753   bytes retrieved without knowing the size of the representation.
754</t>
755<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="suffix-byte-range-spec"/><iref primary="true" item="Grammar" subitem="suffix-length"/>
756  <x:ref>suffix-byte-range-spec</x:ref> = "-" <x:ref>suffix-length</x:ref>
757  <x:ref>suffix-length</x:ref> = 1*<x:ref>DIGIT</x:ref>
758</artwork></figure>
759<t>
760   A suffix-byte-range-spec is used to specify the suffix of the
761   representation body, of a length given by the suffix-length value. (That is,
762   this form specifies the last N bytes of a representation.) If the
763   representation is shorter than the specified suffix-length, the entire
764   representation is used.
765</t>
766<t>
767   If a syntactically valid byte-range-set includes at least one byte-range-spec
768   whose first-byte-pos is less than the current length of
769   the representation, or at least one suffix-byte-range-spec with a non-zero
770   suffix-length, then the byte-range-set is satisfiable.
771   Otherwise, the byte-range-set is unsatisfiable. If the byte-range-set
772   is unsatisfiable, the server &SHOULD; return a response with a
773   <x:ref>416 (Requested Range Not Satisfiable)</x:ref> status code. Otherwise, the server
774   &SHOULD; return a response with a <x:ref>206 (Partial Content)</x:ref> status code
775   containing the satisfiable ranges of the representation.
776</t>
777<t>
778   In the byte range syntax, <x:ref>first-byte-pos</x:ref>,
779   <x:ref>last-byte-pos</x:ref>, and <x:ref>suffix-length</x:ref> are
780   expressed as decimal number of octets.  Since there is no predefined limit
781   to the length of an HTTP payload, recipients &SHOULD; anticipate
782   potentially large decimal numerals and prevent parsing errors due to integer
783   conversion overflows.
784</t>
785<t>
786   Examples of byte-ranges-specifier values (assuming a representation of
787   length 10000):
788  <list style="symbols">
789     <t>The first 500 bytes (byte offsets 0-499, inclusive):
790<figure><artwork type="example" x:indent-with="   ">
791  bytes=0-499
792</artwork></figure>
793    </t>
794     <t>The second 500 bytes (byte offsets 500-999, inclusive):
795<figure><artwork type="example" x:indent-with="   ">
796  bytes=500-999
797</artwork></figure>
798    </t>
799     <t>The final 500 bytes (byte offsets 9500-9999, inclusive):
800<figure><artwork type="example" x:indent-with="   ">
801  bytes=-500
802</artwork></figure>
803    Or:
804<figure><artwork type="example" x:indent-with="   ">
805  bytes=9500-
806</artwork></figure>
807    </t>
808     <t>The first and last bytes only (bytes 0 and 9999):
809<figure><artwork type="example" x:indent-with="   ">
810  bytes=0-0,-1
811</artwork></figure>
812     </t>
813     <t>Several legal but not canonical specifications of the second 500
814        bytes (byte offsets 500-999, inclusive):
815<figure><artwork type="example" x:indent-with="   ">
816  bytes=500-600,601-999
817  bytes=500-700,601-999
818</artwork></figure>
819     </t>
820  </list>
821</t>
822</section>
823
824<section title="Range Retrieval Requests" anchor="range.retrieval.requests">
825  <x:anchor-alias value="Range"/>
826  <x:anchor-alias value="other-ranges-specifier"/>
827  <x:anchor-alias value="other-range-set"/>
828<t>
829   The "Range" header field defines the GET method (conditional or
830   not) to request one or more sub-ranges of the response representation body, instead
831   of the entire representation body.
832</t>
833<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Range"/>
834  <x:ref>Range</x:ref> = <x:ref>byte-ranges-specifier</x:ref> / <x:ref>other-ranges-specifier</x:ref>
835  <x:ref>other-ranges-specifier</x:ref> = <x:ref>other-range-unit</x:ref> "=" <x:ref>other-range-set</x:ref>
836  <x:ref>other-range-set</x:ref> = 1*<x:ref>CHAR</x:ref>
837</artwork></figure>
838<t>
839   A server &MAY; ignore the Range header field. However, origin
840   servers and intermediate caches ought to support byte ranges when
841   possible, since Range supports efficient recovery from partially
842   failed transfers, and supports efficient partial retrieval of large
843   representations.
844</t>
845<t>
846   If the server supports the Range header field and the specified range or
847   ranges are appropriate for the representation:
848  <list style="symbols">
849     <t>The presence of a Range header field in an unconditional GET modifies
850        what is returned if the GET is otherwise successful. In other
851        words, the response carries a status code of <x:ref>206 (Partial Content)</x:ref>
852        instead of <x:ref>200 (OK)</x:ref>.</t>
853
854     <t>The presence of a Range header field in a conditional GET (a request
855        using one or both of <x:ref>If-Modified-Since</x:ref> and
856        <x:ref>If-None-Match</x:ref>, or one or both of
857        <x:ref>If-Unmodified-Since</x:ref> and <x:ref>If-Match</x:ref>) modifies
858        what is returned if the GET is otherwise successful and the
859        condition is true. It does not affect the <x:ref>304 (Not Modified)</x:ref>
860        response returned if the conditional is false.</t>
861  </list>
862</t>
863<t>
864   In some cases, it might be more appropriate to use the If-Range
865   header field (see <xref target="header.if-range"/>) in addition to the Range
866   header field.
867</t>
868<t>
869   If a proxy that supports ranges receives a Range request, forwards
870   the request to an inbound server, and receives an entire representation in
871   reply, it &MAY; only return the requested range to its client.
872</t>
873</section>
874</section>
875</section>
876
877<section title="IANA Considerations" anchor="IANA.considerations">
878
879<section title="Status Code Registration" anchor="status.code.registration">
880<t>
881   The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
882   shall be updated with the registrations below:
883</t>
884<?BEGININC p5-range.iana-status-codes ?>
885<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
886<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
887   <ttcol>Value</ttcol>
888   <ttcol>Description</ttcol>
889   <ttcol>Reference</ttcol>
890   <c>206</c>
891   <c>Partial Content</c>
892   <c>
893      <xref target="status.206"/>
894   </c>
895   <c>416</c>
896   <c>Requested Range Not Satisfiable</c>
897   <c>
898      <xref target="status.416"/>
899   </c>
900</texttable>
901<!--(END)-->
902<?ENDINC p5-range.iana-status-codes ?>
903</section>
904
905<section title="Header Field Registration" anchor="header.field.registration">
906<t>
907   The Message Header Field Registry located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> shall be updated
908   with the permanent registrations below (see <xref target="RFC3864"/>):
909</t>
910<?BEGININC p5-range.iana-headers ?>
911<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
912<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
913   <ttcol>Header Field Name</ttcol>
914   <ttcol>Protocol</ttcol>
915   <ttcol>Status</ttcol>
916   <ttcol>Reference</ttcol>
917
918   <c>Accept-Ranges</c>
919   <c>http</c>
920   <c>standard</c>
921   <c>
922      <xref target="header.accept-ranges"/>
923   </c>
924   <c>Content-Range</c>
925   <c>http</c>
926   <c>standard</c>
927   <c>
928      <xref target="header.content-range"/>
929   </c>
930   <c>If-Range</c>
931   <c>http</c>
932   <c>standard</c>
933   <c>
934      <xref target="header.if-range"/>
935   </c>
936   <c>Range</c>
937   <c>http</c>
938   <c>standard</c>
939   <c>
940      <xref target="header.range"/>
941   </c>
942</texttable>
943<!--(END)-->
944<?ENDINC p5-range.iana-headers ?>
945<t>
946   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
947</t>
948</section>
949
950<section title="Range Specifier Registration" anchor="range.specifier.registration">
951<t>
952  The registration procedure for HTTP Range Specifiers is defined by
953  <xref target="range.specifier.registry"/> of this document.
954</t>
955<t>
956   The HTTP Range Specifier Registry shall be created at <eref target="http://www.iana.org/assignments/http-range-specifiers"/>
957   and be populated with the registrations below:
958</t>
959<texttable align="left" suppress-title="true" anchor="iana.range.specifiers.table">
960   <ttcol>Range Specifier Name</ttcol>
961   <ttcol>Description</ttcol>
962   <ttcol>Reference</ttcol>
963
964   <c>bytes</c>
965   <c>a range of octets</c>
966   <c><xref target="range.units"/></c>
967
968   <c>none</c>
969   <c>reserved as keyword, indicating no ranges are supported</c>
970   <c><xref target="header.accept-ranges"/></c>
971</texttable>
972<t>
973   The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
974</t>
975</section>
976</section>
977
978<section title="Security Considerations" anchor="security.considerations">
979<t>
980   This section is meant to inform application developers, information
981   providers, and users of the security limitations in HTTP/1.1 as
982   described by this document. The discussion does not include
983   definitive solutions to the problems revealed, though it does make
984   some suggestions for reducing security risks.
985</t>
986<section title="Overlapping Ranges" anchor="overlapping.ranges">
987<t>
988   Range requests containing overlapping ranges can lead to the situation
989   where a server is sending far more data than the size of the complete
990   resource representation.
991</t>
992</section>
993</section>
994
995<section title="Acknowledgments" anchor="acks">
996<t>
997  See &acks;.
998</t>
999</section>
1000</middle>
1001<back>
1002
1003<references title="Normative References">
1004
1005<reference anchor="Part1">
1006  <front>
1007    <title>HTTP/1.1, part 1: URIs, Connections, and Message Parsing</title>
1008    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1009      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1010      <address><email>fielding@gbiv.com</email></address>
1011    </author>
1012    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1013      <organization abbrev="W3C">World Wide Web Consortium</organization>
1014      <address><email>ylafon@w3.org</email></address>
1015    </author>
1016    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1017      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1018      <address><email>julian.reschke@greenbytes.de</email></address>
1019    </author>
1020    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1021  </front>
1022  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-&ID-VERSION;"/>
1023  <x:source href="p1-messaging.xml" basename="p1-messaging">
1024    <x:defines>Content-Length</x:defines>
1025  </x:source>
1026</reference>
1027
1028<reference anchor="Part2">
1029  <front>
1030    <title>HTTP/1.1, part 2: Message Semantics, Payload and Content Negotiation</title>
1031    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1032      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1033      <address><email>fielding@gbiv.com</email></address>
1034    </author>
1035    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1036      <organization abbrev="W3C">World Wide Web Consortium</organization>
1037      <address><email>ylafon@w3.org</email></address>
1038    </author>
1039    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1040      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1041      <address><email>julian.reschke@greenbytes.de</email></address>
1042    </author>
1043    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1044  </front>
1045  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-&ID-VERSION;"/>
1046  <x:source href="p2-semantics.xml" basename="p2-semantics">
1047    <x:defines>200 (OK)</x:defines>
1048    <x:defines>410 (Gone)</x:defines>
1049    <x:defines>Content-Location</x:defines>
1050    <x:defines>Content-Type</x:defines>
1051    <x:defines>Location</x:defines>
1052  </x:source>
1053</reference>
1054
1055<reference anchor="Part4">
1056  <front>
1057    <title>HTTP/1.1, part 4: Conditional Requests</title>
1058    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1059      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1060      <address><email>fielding@gbiv.com</email></address>
1061    </author>
1062    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1063      <organization abbrev="W3C">World Wide Web Consortium</organization>
1064      <address><email>ylafon@w3.org</email></address>
1065    </author>
1066    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1067      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1068      <address><email>julian.reschke@greenbytes.de</email></address>
1069    </author>
1070    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1071  </front>
1072  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-&ID-VERSION;"/>
1073  <x:source href="p4-conditional.xml" basename="p4-conditional">
1074    <x:defines>304 (Not Modified)</x:defines>
1075    <x:defines>ETag</x:defines>
1076    <x:defines>If-Match</x:defines>
1077    <x:defines>If-Modified-Since</x:defines>
1078    <x:defines>If-None-Match</x:defines>
1079    <x:defines>If-Unmodified-Since</x:defines>
1080    <x:defines>Last-Modified</x:defines>
1081  </x:source>
1082</reference>
1083
1084<reference anchor="Part6">
1085  <front>
1086    <title>HTTP/1.1, part 6: Caching</title>
1087    <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
1088      <organization abbrev="Adobe">Adobe Systems Incorporated</organization>
1089      <address><email>fielding@gbiv.com</email></address>
1090    </author>
1091    <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
1092      <organization abbrev="W3C">World Wide Web Consortium</organization>
1093      <address><email>ylafon@w3.org</email></address>
1094    </author>
1095    <author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
1096      <organization>Rackspace</organization>
1097      <address><email>mnot@mnot.net</email></address>
1098    </author>
1099    <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
1100      <organization abbrev="greenbytes">greenbytes GmbH</organization>
1101      <address><email>julian.reschke@greenbytes.de</email></address>
1102    </author>
1103    <date month="&ID-MONTH;" year="&ID-YEAR;"/>
1104  </front>
1105  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
1106  <x:source href="p6-cache.xml" basename="p6-cache">
1107    <x:defines>Cache-Control</x:defines>
1108    <x:defines>Expires</x:defines>
1109    <x:defines>Vary</x:defines>
1110  </x:source>
1111</reference>
1112
1113<reference anchor="RFC2046">
1114  <front>
1115    <title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
1116    <author initials="N." surname="Freed" fullname="Ned Freed">
1117      <organization>Innosoft International, Inc.</organization>
1118      <address><email>ned@innosoft.com</email></address>
1119    </author>
1120    <author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
1121      <organization>First Virtual Holdings</organization>
1122      <address><email>nsb@nsb.fv.com</email></address>
1123    </author>
1124    <date month="November" year="1996"/>
1125  </front>
1126  <seriesInfo name="RFC" value="2046"/>
1127</reference>
1128
1129<reference anchor="RFC2119">
1130  <front>
1131    <title>Key words for use in RFCs to Indicate Requirement Levels</title>
1132    <author initials="S." surname="Bradner" fullname="Scott Bradner">
1133      <organization>Harvard University</organization>
1134      <address><email>sob@harvard.edu</email></address>
1135    </author>
1136    <date month="March" year="1997"/>
1137  </front>
1138  <seriesInfo name="BCP" value="14"/>
1139  <seriesInfo name="RFC" value="2119"/>
1140</reference>
1141
1142<reference anchor="RFC5234">
1143  <front>
1144    <title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
1145    <author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
1146      <organization>Brandenburg InternetWorking</organization>
1147      <address>
1148        <email>dcrocker@bbiw.net</email>
1149      </address> 
1150    </author>
1151    <author initials="P." surname="Overell" fullname="Paul Overell">
1152      <organization>THUS plc.</organization>
1153      <address>
1154        <email>paul.overell@thus.net</email>
1155      </address>
1156    </author>
1157    <date month="January" year="2008"/>
1158  </front>
1159  <seriesInfo name="STD" value="68"/>
1160  <seriesInfo name="RFC" value="5234"/>
1161</reference>
1162
1163</references>
1164
1165<references title="Informative References">
1166
1167<reference anchor="RFC2616">
1168  <front>
1169    <title>Hypertext Transfer Protocol -- HTTP/1.1</title>
1170    <author initials="R." surname="Fielding" fullname="R. Fielding">
1171      <organization>University of California, Irvine</organization>
1172      <address><email>fielding@ics.uci.edu</email></address>
1173    </author>
1174    <author initials="J." surname="Gettys" fullname="J. Gettys">
1175      <organization>W3C</organization>
1176      <address><email>jg@w3.org</email></address>
1177    </author>
1178    <author initials="J." surname="Mogul" fullname="J. Mogul">
1179      <organization>Compaq Computer Corporation</organization>
1180      <address><email>mogul@wrl.dec.com</email></address>
1181    </author>
1182    <author initials="H." surname="Frystyk" fullname="H. Frystyk">
1183      <organization>MIT Laboratory for Computer Science</organization>
1184      <address><email>frystyk@w3.org</email></address>
1185    </author>
1186    <author initials="L." surname="Masinter" fullname="L. Masinter">
1187      <organization>Xerox Corporation</organization>
1188      <address><email>masinter@parc.xerox.com</email></address>
1189    </author>
1190    <author initials="P." surname="Leach" fullname="P. Leach">
1191      <organization>Microsoft Corporation</organization>
1192      <address><email>paulle@microsoft.com</email></address>
1193    </author>
1194    <author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
1195      <organization>W3C</organization>
1196      <address><email>timbl@w3.org</email></address>
1197    </author>
1198    <date month="June" year="1999"/>
1199  </front>
1200  <seriesInfo name="RFC" value="2616"/>
1201</reference>
1202
1203<reference anchor='RFC3864'>
1204  <front>
1205    <title>Registration Procedures for Message Header Fields</title>
1206    <author initials='G.' surname='Klyne' fullname='G. Klyne'>
1207      <organization>Nine by Nine</organization>
1208      <address><email>GK-IETF@ninebynine.org</email></address>
1209    </author>
1210    <author initials='M.' surname='Nottingham' fullname='M. Nottingham'>
1211      <organization>BEA Systems</organization>
1212      <address><email>mnot@pobox.com</email></address>
1213    </author>
1214    <author initials='J.' surname='Mogul' fullname='J. Mogul'>
1215      <organization>HP Labs</organization>
1216      <address><email>JeffMogul@acm.org</email></address>
1217    </author>
1218    <date year='2004' month='September' />
1219  </front>
1220  <seriesInfo name='BCP' value='90' />
1221  <seriesInfo name='RFC' value='3864' />
1222</reference>
1223
1224<reference anchor="RFC4288">
1225  <front>
1226    <title>Media Type Specifications and Registration Procedures</title>
1227    <author initials="N." surname="Freed" fullname="N. Freed">
1228      <organization>Sun Microsystems</organization>
1229      <address>
1230        <email>ned.freed@mrochek.com</email>
1231      </address>
1232    </author>
1233    <author initials="J." surname="Klensin" fullname="J. Klensin">
1234      <address>
1235        <email>klensin+ietf@jck.com</email>
1236      </address>
1237    </author>
1238    <date year="2005" month="December"/>
1239  </front>
1240  <seriesInfo name="BCP" value="13"/>
1241  <seriesInfo name="RFC" value="4288"/>
1242</reference>
1243
1244<reference anchor='RFC5226'>
1245  <front>
1246    <title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
1247    <author initials='T.' surname='Narten' fullname='T. Narten'>
1248      <organization>IBM</organization>
1249      <address><email>narten@us.ibm.com</email></address>
1250    </author>
1251    <author initials='H.' surname='Alvestrand' fullname='H. Alvestrand'>
1252      <organization>Google</organization>
1253      <address><email>Harald@Alvestrand.no</email></address>
1254    </author>
1255    <date year='2008' month='May' />
1256  </front>
1257  <seriesInfo name='BCP' value='26' />
1258  <seriesInfo name='RFC' value='5226' />
1259</reference>
1260
1261</references>
1262
1263<section title="Internet Media Type multipart/byteranges" anchor="internet.media.type.multipart.byteranges">
1264<iref item="Media Type" subitem="multipart/byteranges" primary="true"/>
1265<iref item="multipart/byteranges Media Type" primary="true"/>
1266<t>
1267   When an HTTP <x:ref>206 (Partial Content)</x:ref> response message includes the
1268   content of multiple ranges (a response to a request for multiple
1269   non-overlapping ranges), these are transmitted as a multipart
1270   message body (<xref target="RFC2046" x:fmt="," x:sec="5.1"/>). The media type for this purpose is called
1271   "multipart/byteranges".  The following is to be registered with IANA <xref target="RFC4288"/>.
1272</t>
1273<t>
1274   The multipart/byteranges media type includes one or more parts, each
1275   with its own <x:ref>Content-Type</x:ref> and <x:ref>Content-Range</x:ref>
1276   fields. The required boundary parameter specifies the boundary string used
1277   to separate each body-part.
1278</t>
1279<t>
1280  <list style="hanging" x:indent="12em">
1281    <t hangText="Type name:">
1282      multipart
1283    </t>
1284    <t hangText="Subtype name:">
1285      byteranges
1286    </t>
1287    <t hangText="Required parameters:">
1288      boundary
1289    </t>
1290    <t hangText="Optional parameters:">
1291      none
1292    </t>
1293    <t hangText="Encoding considerations:">
1294      only "7bit", "8bit", or "binary" are permitted
1295    </t>
1296    <t hangText="Security considerations:">
1297      none
1298    </t>
1299    <t hangText="Interoperability considerations:">
1300      none
1301    </t>
1302    <t hangText="Published specification:">
1303      This specification (see <xref target="internet.media.type.multipart.byteranges"/>).
1304    </t>
1305    <t hangText="Applications that use this media type:">
1306      HTTP components supporting multiple ranges in a single request.
1307    </t>
1308    <t hangText="Additional information:">
1309      <list style="hanging">
1310        <t hangText="Magic number(s):">none</t>
1311        <t hangText="File extension(s):">none</t>
1312        <t hangText="Macintosh file type code(s):">none</t>
1313      </list>
1314    </t>
1315    <t hangText="Person and email address to contact for further information:">
1316      See Authors Section.
1317    </t>
1318    <t hangText="Intended usage:">
1319      COMMON
1320    </t>
1321    <t hangText="Restrictions on usage:">
1322      none
1323    </t>
1324    <t hangText="Author/Change controller:">
1325      IESG
1326    </t>
1327  </list>
1328</t>
1329<x:note>
1330  <t>
1331    &Note; Despite the name "multipart/byteranges" is not limited to the byte ranges only.
1332  </t>
1333</x:note>
1334<figure><preamble>
1335   For example:
1336</preamble><artwork type="example">
1337  HTTP/1.1 206 Partial Content
1338  Date: Wed, 15 Nov 1995 06:25:24 GMT
1339  Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
1340  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1341 
1342  --THIS_STRING_SEPARATES
1343  Content-type: application/pdf
1344  Content-range: bytes 500-999/8000
1345 
1346  ...the first range...
1347  --THIS_STRING_SEPARATES
1348  Content-type: application/pdf
1349  Content-range: bytes 7000-7999/8000
1350 
1351  ...the second range
1352  --THIS_STRING_SEPARATES--
1353</artwork></figure>
1354<figure><preamble>
1355   Another example, using the "exampleunit" range unit:
1356</preamble>
1357<artwork type="example">
1358  HTTP/1.1 206 Partial Content
1359  Date: Tue, 14 Nov 1995 06:25:24 GMT
1360  Last-Modified: Tue, 14 July 04:58:08 GMT
1361  Content-type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
1362 
1363  --THIS_STRING_SEPARATES
1364  Content-type: video/example
1365  Content-range: exampleunit 1.2-4.3/25
1366 
1367  ...the first range...
1368  --THIS_STRING_SEPARATES
1369  Content-type: video/example
1370  Content-range: exampleunit 11.2-14.3/25
1371 
1372  ...the second range
1373  --THIS_STRING_SEPARATES--
1374</artwork>
1375</figure>
1376<t>
1377  Notes:
1378  <list style="numbers">
1379      <t>Additional CRLFs &MAY; precede the first boundary string in the body.</t>
1380
1381      <t>Although <xref target="RFC2046"/> permits the boundary string to be
1382         quoted, some existing implementations handle a quoted boundary
1383         string incorrectly.</t>
1384
1385      <t>A number of clients and servers were coded to an early draft
1386         of the byteranges specification to use a media type of
1387         multipart/x-byteranges<iref item="multipart/x-byteranges Media Type"/><iref item="Media Type" subitem="multipart/x-byteranges"/>, which is almost, but not quite
1388         compatible with the version documented in HTTP/1.1.</t>
1389  </list>
1390</t>
1391</section>
1392
1393<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
1394<t>
1395  Introduce Range Specifier Registry.
1396  (<xref target="range.specifier.registry"/>)
1397</t>
1398<t>
1399  Clarify that it is not ok to use a weak validator in a <x:ref>206</x:ref> response.
1400  (<xref target="status.206"/>)
1401</t>
1402<t>
1403  Change ABNF productions for header fields to only define the field value.
1404  (<xref target="header.field.definitions"/>)
1405</t>
1406<t>
1407  Clarify that multipart/byteranges can consist of a single part.
1408  (<xref target="internet.media.type.multipart.byteranges"/>)
1409</t>
1410</section>
1411
1412<?BEGININC p5-range.abnf-appendix ?>
1413<section xmlns:x="http://purl.org/net/xml2rfc/ext" title="Collected ABNF" anchor="collected.abnf">
1414<figure>
1415<artwork type="abnf" name="p5-range.parsed-abnf">
1416<x:ref>Accept-Ranges</x:ref> = acceptable-ranges
1417
1418<x:ref>Content-Range</x:ref> = byte-content-range-spec / other-content-range-spec
1419
1420<x:ref>HTTP-date</x:ref> = &lt;HTTP-date, defined in [Part2], Section 5.1&gt;
1421
1422<x:ref>If-Range</x:ref> = entity-tag / HTTP-date
1423
1424<x:ref>OWS</x:ref> = &lt;OWS, defined in [Part1], Section 3.2.1&gt;
1425
1426<x:ref>Range</x:ref> = byte-ranges-specifier / other-ranges-specifier
1427
1428<x:ref>acceptable-ranges</x:ref> = ( *( "," OWS ) range-unit *( OWS "," [ OWS
1429 range-unit ] ) ) / "none"
1430
1431<x:ref>byte-content-range-spec</x:ref> = bytes-unit SP byte-range-resp-spec "/" (
1432 instance-length / "*" )
1433<x:ref>byte-range-resp-spec</x:ref> = ( first-byte-pos "-" last-byte-pos ) / "*"
1434<x:ref>byte-range-set</x:ref> = *( "," OWS ) ( byte-range-spec /
1435 suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
1436 suffix-byte-range-spec ) ] )
1437<x:ref>byte-range-spec</x:ref> = first-byte-pos "-" [ last-byte-pos ]
1438<x:ref>byte-ranges-specifier</x:ref> = bytes-unit "=" byte-range-set
1439<x:ref>bytes-unit</x:ref> = "bytes"
1440
1441<x:ref>entity-tag</x:ref> = &lt;entity-tag, defined in [Part4], Section 2.3&gt;
1442
1443<x:ref>first-byte-pos</x:ref> = 1*DIGIT
1444
1445<x:ref>instance-length</x:ref> = 1*DIGIT
1446
1447<x:ref>last-byte-pos</x:ref> = 1*DIGIT
1448
1449<x:ref>other-content-range-spec</x:ref> = other-range-unit SP other-range-resp-spec
1450<x:ref>other-range-resp-spec</x:ref> = *CHAR
1451<x:ref>other-range-set</x:ref> = 1*CHAR
1452<x:ref>other-range-unit</x:ref> = token
1453<x:ref>other-ranges-specifier</x:ref> = other-range-unit "=" other-range-set
1454
1455<x:ref>range-unit</x:ref> = bytes-unit / other-range-unit
1456
1457<x:ref>suffix-byte-range-spec</x:ref> = "-" suffix-length
1458<x:ref>suffix-length</x:ref> = 1*DIGIT
1459
1460<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.4&gt;
1461</artwork>
1462</figure>
1463<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
1464; Accept-Ranges defined but not used
1465; Content-Range defined but not used
1466; If-Range defined but not used
1467; Range defined but not used
1468</artwork></figure></section>
1469<?ENDINC p5-range.abnf-appendix ?>
1470
1471
1472<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
1473
1474<section title="Since RFC 2616">
1475<t>
1476  Extracted relevant partitions from <xref target="RFC2616"/>.
1477</t>
1478</section>
1479
1480<section title="Since draft-ietf-httpbis-p5-range-00">
1481<t>
1482  Closed issues:
1483  <list style="symbols"> 
1484    <t>
1485      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/18"/>:
1486      "Cache validators in 206 responses"
1487      (<eref target="http://purl.org/NET/http-errata#ifrange206"/>)
1488    </t>
1489    <t>
1490      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>:
1491      "Normative and Informative references"
1492    </t>
1493    <t>
1494      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>:
1495      "Normative up-to-date references"
1496    </t>
1497  </list>
1498</t>
1499</section>
1500
1501<section title="Since draft-ietf-httpbis-p5-range-01">
1502<t>
1503  Closed issues:
1504  <list style="symbols"> 
1505    <t>
1506      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>:
1507      "Updating to RFC4288"
1508    </t>
1509  </list>
1510</t>
1511<t>
1512  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1513  <list style="symbols"> 
1514    <t>
1515      Add explicit references to BNF syntax and rules imported from other parts of the specification.
1516    </t>
1517  </list>
1518</t>
1519</section>
1520
1521<section title="Since draft-ietf-httpbis-p5-range-02" anchor="changes.since.02">
1522<t>
1523  Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>):
1524  <list style="symbols"> 
1525    <t>
1526      Reference RFC 3984, and update header field registrations for headers defined
1527      in this document.
1528    </t>
1529  </list>
1530</t>
1531</section>
1532
1533<section title="Since draft-ietf-httpbis-p5-range-03" anchor="changes.since.03">
1534<t>
1535  None.
1536</t>
1537</section>
1538
1539<section title="Since draft-ietf-httpbis-p5-range-04" anchor="changes.since.04">
1540<t>
1541  Closed issues:
1542  <list style="symbols"> 
1543    <t>
1544      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/133"/>:
1545      "multipart/byteranges minimum number of parts"
1546    </t>
1547  </list>
1548</t>
1549<t>
1550  Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1551  <list style="symbols"> 
1552    <t>
1553      Use "/" instead of "|" for alternatives.
1554    </t>
1555    <t>
1556      Introduce new ABNF rules for "bad" whitespace ("BWS"), optional
1557      whitespace ("OWS") and required whitespace ("RWS").
1558    </t>
1559    <t>
1560      Rewrite ABNFs to spell out whitespace rules, factor out
1561      header field value format definitions.
1562    </t>
1563  </list>
1564</t>
1565</section>
1566
1567<section title="Since draft-ietf-httpbis-p5-range-05" anchor="changes.since.05">
1568<t>
1569  Closed issues:
1570  <list style="symbols"> 
1571    <t>
1572      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/142"/>:
1573      "State base for *-byte-pos and suffix-length"
1574    </t>
1575  </list>
1576</t>
1577<t>
1578  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1579  <list style="symbols"> 
1580    <t>
1581      Remove bias in favor of byte ranges; allow custom ranges in ABNF.
1582    </t>
1583  </list>
1584</t>
1585<t>
1586  Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>):
1587  <list style="symbols"> 
1588    <t>
1589      Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.
1590    </t>
1591  </list>
1592</t>
1593</section>
1594
1595<section title="Since draft-ietf-httpbis-p5-range-06" anchor="changes.since.06">
1596<t>
1597  Closed issues:
1598  <list style="symbols"> 
1599    <t>
1600      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/161"/>:
1601      "base for numeric protocol elements"
1602    </t>
1603  </list>
1604</t>
1605</section>
1606
1607<section title="Since draft-ietf-httpbis-p5-range-07" anchor="changes.since.07">
1608<t>
1609  Closed issues:
1610  <list style="symbols">
1611    <t>
1612      Fixed discrepancy in the If-Range definition about allowed validators.
1613    </t>
1614    <t>
1615      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/150" />: "multipart/byteranges for custom range units"
1616    </t>
1617    <t>
1618      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/151" />: "range unit missing from other-ranges-specifier in Range header"
1619    </t>
1620    <t>
1621      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/198"/>:
1622      "move IANA registrations for optional status codes"
1623    </t>
1624  </list>
1625</t>
1626</section>
1627
1628<section title="Since draft-ietf-httpbis-p5-range-08" anchor="changes.since.08">
1629<t>
1630  No significant changes.
1631</t>
1632</section>
1633
1634<section title="Since draft-ietf-httpbis-p5-range-09" anchor="changes.since.09">
1635<t>
1636 No significant changes.
1637</t>
1638</section>
1639
1640<section title="Since draft-ietf-httpbis-p5-range-10" anchor="changes.since.10">
1641<t>
1642  Closed issues:
1643  <list style="symbols"> 
1644    <t>
1645      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>:
1646      "Clarify 'Requested Variant'"
1647    </t>
1648    <t>
1649      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>:
1650      "Clarify entity / representation / variant terminology"
1651    </t>
1652    <t>
1653      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>:
1654      "consider removing the 'changes from 2068' sections"
1655    </t>
1656  </list>
1657</t>
1658<t>
1659  Ongoing work on Custom Ranges (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/85"/>):
1660  <list style="symbols"> 
1661    <t>
1662      Add IANA registry.
1663    </t>
1664  </list>
1665</t>
1666</section>
1667
1668<section title="Since draft-ietf-httpbis-p5-range-11" anchor="changes.since.11">
1669<t>
1670  Closed issues:
1671  <list style="symbols"> 
1672    <t>
1673      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/217"/>:
1674      "Caches can't be required to serve ranges"
1675    </t>
1676  </list>
1677</t>
1678</section>
1679
1680<section title="Since draft-ietf-httpbis-p5-range-12" anchor="changes.since.12">
1681<t>
1682  Closed issues:
1683  <list style="symbols"> 
1684    <t>
1685      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>:
1686      "Header Classification"
1687    </t>
1688  </list>
1689</t>
1690</section>
1691
1692<section title="Since draft-ietf-httpbis-p5-range-13" anchor="changes.since.13">
1693<t>
1694  Closed issues:
1695  <list style="symbols">
1696    <t>
1697      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>:
1698      "untangle ABNFs for header fields"
1699    </t>
1700  </list>
1701</t>
1702</section>
1703
1704<section title="Since draft-ietf-httpbis-p5-range-14" anchor="changes.since.14">
1705<t>
1706  None.
1707</t>
1708</section>
1709
1710<section title="Since draft-ietf-httpbis-p5-range-15" anchor="changes.since.15">
1711<t>
1712  Closed issues:
1713  <list style="symbols">
1714    <t>
1715      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/175"/>:
1716      "Security consideration: range flooding"
1717    </t>
1718  </list>
1719</t>
1720</section>
1721
1722<section title="Since draft-ietf-httpbis-p5-range-16" anchor="changes.since.16">
1723<t>
1724  Closed issues:
1725  <list style="symbols"> 
1726    <t>
1727      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/186"/>:
1728      "Document HTTP's error-handling philosophy"
1729    </t>
1730    <t>
1731      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/301"/>:
1732      "Content-Range on responses other than 206"
1733    </t>
1734    <t>
1735      <eref target="http://trac.tools.ietf.org/wg/httpbis/trac/ticket/319"/>:
1736      "case sensitivity of ranges in p5"
1737    </t>
1738  </list>
1739</t>
1740</section>
1741
1742<section title="Since draft-ietf-httpbis-p5-range-17" anchor="changes.since.17">
1743<t>
1744  None.
1745</t>
1746</section>
1747
1748<section title="Since draft-ietf-httpbis-p5-range-18" anchor="changes.since.18">
1749<t>
1750  Closed issues:
1751  <list style="symbols"> 
1752    <t>
1753      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/311"/>:
1754      "Add limitations to Range to reduce its use as a denial-of-service tool"
1755    </t>
1756  </list>
1757</t>
1758</section>
1759
1760<section title="Since draft-ietf-httpbis-p5-range-19" anchor="changes.since.19">
1761<t>
1762  Closed issues:
1763  <list style="symbols"> 
1764    <t>
1765      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/358"/>:
1766      "ABNF list expansion code problem"
1767    </t>
1768    <t>
1769      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/361"/>:
1770      "ABNF requirements for recipients"
1771    </t>
1772    <t>
1773      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/367"/>:
1774      "reserve 'none' as byte range unit"
1775    </t>
1776    <t>
1777      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/368"/>:
1778      "note introduction of new IANA registries as normative changes"
1779    </t>
1780    <t>
1781      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/369"/>:
1782      "range units vs leading zeroes vs size"
1783    </t>
1784  </list>
1785</t>
1786</section>
1787
1788</section>
1789
1790</back>
1791</rfc>
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