One document matched: draft-ietf-httpbis-p5-range-24.xml
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<rfc obsoletes="2616" category="std" ipr="pre5378Trust200902" docName="draft-ietf-httpbis-p5-range-24">
<front>
<title abbrev="HTTP/1.1 Range Requests">Hypertext Transfer Protocol (HTTP/1.1): Range Requests</title>
<author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
<organization abbrev="Adobe">Adobe Systems Incorporated</organization>
<address>
<postal>
<street>345 Park Ave</street>
<city>San Jose</city>
<region>CA</region>
<code>95110</code>
<country>USA</country>
</postal>
<email>fielding@gbiv.com</email>
<uri>http://roy.gbiv.com/</uri>
</address>
</author>
<author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">
<organization abbrev="W3C">World Wide Web Consortium</organization>
<address>
<postal>
<street>W3C / ERCIM</street>
<street>2004, rte des Lucioles</street>
<city>Sophia-Antipolis</city>
<region>AM</region>
<code>06902</code>
<country>France</country>
</postal>
<email>ylafon@w3.org</email>
<uri>http://www.raubacapeu.net/people/yves/</uri>
</address>
</author>
<author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
<organization abbrev="greenbytes">greenbytes GmbH</organization>
<address>
<postal>
<street>Hafenweg 16</street>
<city>Muenster</city><region>NW</region><code>48155</code>
<country>Germany</country>
</postal>
<email>julian.reschke@greenbytes.de</email>
<uri>http://greenbytes.de/tech/webdav/</uri>
</address>
</author>
<date month="September" year="2013" day="25"/>
<workgroup>HTTPbis Working Group</workgroup>
<abstract>
<t>
The Hypertext Transfer Protocol (HTTP) is an application-level protocol for
distributed, collaborative, hypertext information systems. This document
defines range requests and the rules for constructing and combining
responses to those requests.
</t>
</abstract>
<note title="Editorial Note (To be removed by RFC Editor)">
<t>
Discussion of this draft takes place on the HTTPBIS working group
mailing list (ietf-http-wg@w3.org), which is archived at
<eref target="http://lists.w3.org/Archives/Public/ietf-http-wg/"/>.
</t>
<t>
The current issues list is at
<eref target="http://tools.ietf.org/wg/httpbis/trac/report/3"/> and related
documents (including fancy diffs) can be found at
<eref target="http://tools.ietf.org/wg/httpbis/"/>.
</t>
<t>
The changes in this draft are summarized in <xref target="changes.since.23"/>.
</t>
</note>
</front>
<middle>
<section title="Introduction" anchor="introduction">
<t>
Hypertext Transfer Protocol (HTTP) clients often encounter interrupted data
transfers as a result of canceled requests or dropped connections. When a
client has stored a partial representation, it is desirable to request the
remainder of that representation in a subsequent request rather than
transfer the entire representation. Likewise, devices with limited local
storage might benefit from being able to request only a subset of a larger
representation, such as a single page of a very large document, or the
dimensions of an embedded image.
</t>
<t>
This document defines HTTP/1.1 range requests, partial responses, and the
multipart/byteranges media type. Range requests are an OPTIONAL feature
of HTTP, designed so that recipients not implementing this feature (or not
supporting it for the target resource) can respond as if it is a normal
GET request without impacting interoperability. Partial responses are
indicated by a distinct status code to not be mistaken for full responses
by caches that might not implement the feature.
</t>
<t>
Although the range request mechanism is designed to allow for
extensible range types, this specification only defines requests for
byte ranges.
</t>
<section title="Conformance and Error Handling" anchor="conformance">
<t>
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref target="RFC2119"/>.
</t>
<t>
Conformance criteria and considerations regarding error handling
are defined in Section 2.5 of <xref target="Part1"/>.
</t>
</section>
<section title="Syntax Notation" anchor="notation">
<t>
This specification uses the Augmented Backus-Naur Form (ABNF) notation
of <xref target="RFC5234"/> with the list rule extension defined in
Section 7 of <xref target="Part1"/>. <xref target="imported.abnf"/> describes rules imported from
other documents. <xref target="collected.abnf"/> shows the collected ABNF
with the list rule expanded.
</t>
</section>
</section>
<section title="Range Units" anchor="range.units">
<t>
A representation can be partitioned into subranges according to various
structural units, depending on the structure inherent in the
representation's media type. This "range unit" is used
in the <xref target="header.accept-ranges" format="none">Accept-Ranges</xref> (<xref target="header.accept-ranges"/>)
response header field to advertise support for range requests, the
<xref target="header.range" format="none">Range</xref> (<xref target="header.range"/>) request header field
to delineate the parts of a representation that are requested, and the
<xref target="header.content-range" format="none">Content-Range</xref> (<xref target="header.content-range"/>)
payload header field to describe which part of a representation is being
transferred.
</t>
<figure><iref primary="true" item="Grammar" subitem="range-unit"/><iref item="Grammar" subitem="bytes-unit"/><iref item="Grammar" subitem="other-range-unit"/><artwork type="abnf2616"><![CDATA[
range-unit = bytes-unit / other-range-unit
]]></artwork></figure>
<section title="Byte Ranges" anchor="byte.ranges">
<t>
Since representation data is transferred in payloads as a sequence of
octets, a byte range is a meaningful substructure for any representation
transferable over HTTP (Section 3 of <xref target="Part2"/>). We define the "bytes" range
unit for expressing subranges of the data's octet sequence.
</t>
<figure><iref primary="true" item="Grammar" subitem="bytes-unit"/><artwork type="abnf2616"><![CDATA[
bytes-unit = "bytes"
]]></artwork></figure>
<t anchor="rule.ranges-specifier">
A byte range request can specify a single range of bytes, or a set
of ranges within a single representation.
</t>
<figure><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"/><artwork type="abnf2616"><![CDATA[
byte-ranges-specifier = bytes-unit "=" byte-range-set
byte-range-set = 1#( byte-range-spec / suffix-byte-range-spec )
byte-range-spec = first-byte-pos "-" [ last-byte-pos ]
first-byte-pos = 1*DIGIT
last-byte-pos = 1*DIGIT
]]></artwork></figure>
<t>
The <xref target="rule.ranges-specifier" format="none">first-byte-pos</xref> value in a <xref target="rule.ranges-specifier" format="none">byte-range-spec</xref>
gives the byte-offset of the first byte in a range.
The <xref target="rule.ranges-specifier" format="none">last-byte-pos</xref> value gives the byte-offset of the last
byte in the range; that is, the byte positions specified are inclusive.
Byte offsets start at zero.
</t>
<t>
Examples of <xref target="rule.ranges-specifier" format="none">byte-ranges-specifier</xref> values:
<list style="symbols">
<t>The first 500 bytes (byte offsets 0-499, inclusive):
<figure><artwork type="example"><![CDATA[
bytes=0-499
]]></artwork></figure>
</t>
<t>The second 500 bytes (byte offsets 500-999, inclusive):
<figure><artwork type="example"><![CDATA[
bytes=500-999
]]></artwork></figure>
</t>
</list>
</t>
<t>
A <xref target="rule.ranges-specifier" format="none">byte-range-spec</xref> is invalid if the
<xref target="rule.ranges-specifier" format="none">last-byte-pos</xref> value is present and less than the
<xref target="rule.ranges-specifier" format="none">first-byte-pos</xref>.
</t>
<t>
A client can limit the number of bytes requested without knowing the size
of the selected representation.
If the <xref target="rule.ranges-specifier" format="none">last-byte-pos</xref> value is absent, or if the value is
greater than or equal to the current length of the representation data, the
byte range is interpreted as the remainder of the representation (i.e., the
server replaces the value of <xref target="rule.ranges-specifier" format="none">last-byte-pos</xref> with a value that
is one less than the current length of the selected representation).
</t>
<t>
A client can request the last N bytes of the selected representation using
a <xref target="rule.ranges-specifier" format="none">suffix-byte-range-spec</xref>.
</t>
<figure><iref primary="true" item="Grammar" subitem="suffix-byte-range-spec"/><iref primary="true" item="Grammar" subitem="suffix-length"/><artwork type="abnf2616"><![CDATA[
suffix-byte-range-spec = "-" suffix-length
suffix-length = 1*DIGIT
]]></artwork></figure>
<t>
If the selected representation is shorter than the specified
<xref target="rule.ranges-specifier" format="none">suffix-length</xref>, the entire representation is used.
</t>
<t>
Additional examples, assuming a representation of length 10000:
<list style="symbols">
<t>The final 500 bytes (byte offsets 9500-9999, inclusive):
<figure><artwork type="example"><![CDATA[
bytes=-500
]]></artwork></figure>
Or:
<figure><artwork type="example"><![CDATA[
bytes=9500-
]]></artwork></figure>
</t>
<t>The first and last bytes only (bytes 0 and 9999):
<figure><artwork type="example"><![CDATA[
bytes=0-0,-1
]]></artwork></figure>
</t>
<t>Other valid (but not canonical) specifications of the second 500
bytes (byte offsets 500-999, inclusive):
<figure><artwork type="example"><![CDATA[
bytes=500-600,601-999
bytes=500-700,601-999
]]></artwork></figure>
</t>
</list>
</t>
<t>
If a valid <xref target="rule.ranges-specifier" format="none">byte-range-set</xref> includes at least one
<xref target="rule.ranges-specifier" format="none">byte-range-spec</xref> with a <xref target="rule.ranges-specifier" format="none">first-byte-pos</xref> that is
less than the current length of the representation, or at least one
<xref target="rule.ranges-specifier" format="none">suffix-byte-range-spec</xref> with a non-zero
<xref target="rule.ranges-specifier" format="none">suffix-length</xref>, then the <xref target="rule.ranges-specifier" format="none">byte-range-set</xref> is
satisfiable. Otherwise, the <xref target="rule.ranges-specifier" format="none">byte-range-set</xref> is unsatisfiable.
</t>
<t>
In the byte range syntax, <xref target="rule.ranges-specifier" format="none">first-byte-pos</xref>,
<xref target="rule.ranges-specifier" format="none">last-byte-pos</xref>, and <xref target="rule.ranges-specifier" format="none">suffix-length</xref> are
expressed as decimal number of octets. Since there is no predefined limit
to the length of a payload, recipients ought to anticipate potentially
large decimal numerals and prevent parsing errors due to integer conversion
overflows.
</t>
</section>
<section title="Other Range Units" anchor="range.units.other">
<t>
Range units are intended to be extensible. New range units ought to be
registered with IANA, as defined in <xref target="range.unit.registry"/>.
</t>
<figure><iref primary="true" item="Grammar" subitem="other-range-unit"/><artwork type="abnf2616"><![CDATA[
other-range-unit = token
]]></artwork></figure>
</section>
<section title="Accept-Ranges" anchor="header.accept-ranges">
<iref primary="true" item="Accept-Ranges header field"/>
<t>
The "Accept-Ranges" header field allows a server to indicate that it
supports range requests for the target resource.
</t>
<figure><iref primary="true" item="Grammar" subitem="Accept-Ranges"/><iref primary="true" item="Grammar" subitem="acceptable-ranges"/><artwork type="abnf2616"><![CDATA[
Accept-Ranges = acceptable-ranges
acceptable-ranges = 1#range-unit / "none"
]]></artwork></figure>
<t>
An origin server that supports byte-range requests for a given target
resource MAY send
</t>
<figure><artwork type="example"><![CDATA[
Accept-Ranges: bytes
]]></artwork></figure>
<t>
to indicate what range units are supported. A client MAY generate range
requests without having received this header field for the resource
involved. Range units are defined in <xref target="range.units"/>.
</t>
<t>
A server that does not support any kind of range request for the target
resource resource MAY send
</t>
<figure><artwork type="example"><![CDATA[
Accept-Ranges: none
]]></artwork></figure>
<t>
to advise the client not to attempt a range request.
</t>
</section>
</section>
<section title="Range Requests" anchor="range.requests">
<section title="Range" anchor="header.range">
<iref primary="true" item="Range header field"/>
<t>
The "Range" header field on a GET request modifies the method semantics to
request transfer of only one or more subranges of the selected
representation data, rather than the entire selected representation data.
</t>
<figure><iref primary="true" item="Grammar" subitem="Range"/><artwork type="abnf2616"><![CDATA[
Range = byte-ranges-specifier / other-ranges-specifier
other-ranges-specifier = other-range-unit "=" other-range-set
other-range-set = 1*CHAR
]]></artwork></figure>
<t>
A server MAY ignore the Range header field. However, origin servers and
intermediate caches ought to support byte ranges when possible, since Range
supports efficient recovery from partially failed transfers and partial
retrieval of large representations. A server MUST ignore a Range header
field received with a request method other than GET.
</t>
<t>
An origin server MUST ignore a Range header field that contains a range
unit it does not understand. A proxy MAY discard a Range header
field that contains a range unit it does not understand.
</t>
<t>
A server that supports range requests MAY ignore or reject a
<xref target="header.range" format="none">Range</xref> header field that consists of more than two
overlapping ranges, or a set of many small ranges that are not listed
in ascending order, since both are indications of either a broken client or
a deliberate denial of service attack (<xref target="overlapping.ranges"/>).
A client SHOULD NOT request multiple ranges that are inherently less
efficient to process and transfer than a single range that encompasses the
same data.
</t>
<t>
A client that is requesting multiple ranges SHOULD list those ranges in
ascending order (the order in which they would typically be received in a
complete representation) unless there is a specific need to request a later
part earlier. For example, a user agent processing a large representation
with an internal catalog of parts might need to request later parts first,
particularly if the representation consists of pages stored in reverse
order and the user agent wishes to transfer one page at a time.
</t>
<t>
The Range header field is evaluated after evaluating the precondition header
fields defined in <xref target="Part4"/>, and only if the result in absence
of the Range header field would be a 200 (OK) response. In
other words, Range is ignored when a conditional GET would result in a
304 (Not Modified) response.
</t>
<t>
The If-Range header field (<xref target="header.if-range"/>) can be used as
a precondition to applying the Range header field.
</t>
<t>
If all of the preconditions are true, the server supports the Range header
field for the target resource, and the specified range(s) are valid and
satisfiable (as defined in <xref target="byte.ranges"/>), the
server SHOULD send a <xref target="status.206" format="none">206 (Partial Content)</xref> response with a
payload containing one or more partial representations that correspond to
the satisfiable ranges requested, as defined in
<xref target="range.response"/>.
</t>
<t>
If all of the preconditions are true, the server supports the Range header
field for the target resource, and the specified range(s) are invalid or
unsatisfiable, the server SHOULD send a
<xref target="status.416" format="none">416 (Range Not Satisfiable)</xref> response.
</t>
</section>
<section title="If-Range" anchor="header.if-range">
<iref primary="true" item="If-Range header field"/>
<t>
If a client has a partial copy of a representation and wishes
to have an up-to-date copy of the entire representation, it could use the
<xref target="header.range" format="none">Range</xref> header field with a conditional GET (using
either or both of If-Unmodified-Since and
If-Match.) However, if the precondition fails because the
representation has been modified, the client would then have to make a
second request to obtain the entire current representation.
</t>
<t>
The "If-Range" header field allows a client to "short-circuit" the second
request. Informally, its meaning is: if the representation is unchanged,
send me the part(s) that I am requesting in Range; otherwise, send me the
entire representation.
</t>
<figure><iref primary="true" item="Grammar" subitem="If-Range"/><artwork type="abnf2616"><![CDATA[
If-Range = entity-tag / HTTP-date
]]></artwork></figure>
<t>
A client MUST NOT generate an If-Range header field in a request that
does not contain a <xref target="header.range" format="none">Range</xref> header field.
A server MUST ignore an If-Range header field received in a request that
does not contain a <xref target="header.range" format="none">Range</xref> header field.
An origin server MUST ignore an If-Range header field received in a
request for a target resource that does not support Range requests.
</t>
<t>
A client MUST NOT generate an If-Range header field containing an
entity-tag that is marked as weak.
A client MUST NOT generate an If-Range header field containing an
<xref target="imported.abnf" format="none">HTTP-date</xref> unless the client has no entity-tag for
the corresponding representation and the date is a strong validator
in the sense defined by Section 2.2.2 of <xref target="Part4"/>.
</t>
<t>
A server that evaluates an If-Range precondition MUST use the strong
comparison function when comparing entity-tags (Section 2.3.2 of <xref target="Part4"/>)
and MUST evaluate the condition as false if an <xref target="imported.abnf" format="none">HTTP-date</xref>
validator is provided that is not a strong validator in the sense defined
by Section 2.2.2 of <xref target="Part4"/>.
(A server can distinguish between a valid <xref target="imported.abnf" format="none">HTTP-date</xref> and any
form of entity-tag by examining the first two characters.)
</t>
<t>
If the validator given in the If-Range header field matches the current
validator for the selected representation of the target resource, then
the server SHOULD process the <xref target="header.range" format="none">Range</xref> header field as
requested. If the validator does not match, the server MUST ignore the
<xref target="header.range" format="none">Range</xref> header field.
</t>
</section>
</section>
<section title="Responses to a Range Request" anchor="range.response">
<section title="206 Partial Content" anchor="status.206">
<iref primary="true" item="206 Partial Content (status code)"/>
<t>
The 206 (Partial Content) status code indicates that the
server is successfully fulfilling a range request for the target resource
by transferring one or more parts of the selected representation that
correspond to the satisfiable ranges found in the request's
<xref target="header.range" format="none">Range</xref> header field (<xref target="header.range"/>).
</t>
<t>
If a single part is being transferred, the server generating the 206
response MUST generate a <xref target="header.content-range" format="none">Content-Range</xref> header field,
describing what range of the selected representation is enclosed, and a
payload consisting of the range. For example:
</t>
<figure><artwork type="message/http; msgtype="response""><![CDATA[
HTTP/1.1 206 Partial Content
Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-Range: bytes 21010-47021/47022
Content-Length: 26012
Content-Type: image/gif
... 26012 bytes of partial image data ...
]]></artwork></figure>
<t>
If multiple parts are being transferred, the server generating the 206
response MUST generate a "multipart/byteranges" payload, as defined
in <xref target="internet.media.type.multipart.byteranges"/>, and a
Content-Type header field containing the
multipart/byteranges media type and its required boundary parameter.
To avoid confusion with single part responses, a server MUST NOT generate
a <xref target="header.content-range" format="none">Content-Range</xref> header field in the HTTP header section of a
multiple part response (this field will be sent in each part instead).
</t>
<t>
Within the header area of each body part in the multipart payload, the
server MUST generate a <xref target="header.content-range" format="none">Content-Range</xref> header field
corresponding to the range being enclosed in that body part.
If the selected representation would have had a Content-Type
header field in a 200 (OK) response, the server SHOULD
generate that same Content-Type field in the header area of
each body part. For example:
</t>
<figure><artwork type="message/http; msgtype="response""><![CDATA[
HTTP/1.1 206 Partial Content
Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-Length: 1741
Content-Type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
--THIS_STRING_SEPARATES
Content-Type: application/pdf
Content-Range: bytes 500-999/8000
...the first range...
--THIS_STRING_SEPARATES
Content-Type: application/pdf
Content-Range: bytes 7000-7999/8000
...the second range
--THIS_STRING_SEPARATES--
]]></artwork></figure>
<t>
When multiple ranges are requested, a server MAY coalesce any of the
ranges that overlap or that are separated by a gap that is smaller than the
overhead of sending multiple parts, regardless of the order in which the
corresponding byte-range-spec appeared in the received <xref target="header.range" format="none">Range</xref>
header field. Since the typical overhead between parts of a
multipart/byteranges payload is around 80 bytes, depending on the selected
representation's media type and the chosen boundary parameter length, it
can be less efficient to transfer many small disjoint parts than it is to
transfer the entire selected representation.
</t>
<t>
A server MUST NOT generate a multipart response to a request for a single
range, since a client that does not request multiple parts might not
support multipart responses. However, a server MAY generate a
multipart/byteranges payload with only a single body part if multiple
ranges were requested and only one range was found to be satisfiable or
only one range remained after coalescing.
A client that cannot process a multipart/byteranges response MUST NOT
generate a request that asks for multiple ranges.
</t>
<t>
When a multipart response payload is generated, the server SHOULD send
the parts in the same order that the corresponding byte-range-spec appeared
in the received <xref target="header.range" format="none">Range</xref> header field, excluding those ranges
that were deemed unsatisfiable or that were coalesced into other ranges.
A client that receives a multipart response MUST inspect the
<xref target="header.content-range" format="none">Content-Range</xref> header field present in each body part in
order to determine which range is contained in that body part; a client
cannot rely on receiving the same ranges that it requested, nor the same
order that it requested.
</t>
<t>
When a 206 response is generated, the server MUST generate the following
header fields, in addition to those required above, if the field would
have been sent in a 200 (OK) response to the same request:
Date, Cache-Control, ETag,
Expires, Content-Location, and
Vary.
</t>
<t>
If a 206 is generated in response to a request with an <xref target="header.if-range" format="none">If-Range</xref>
header field, the sender SHOULD NOT generate other representation header
fields beyond those required above, because the client is understood to
already have a prior response containing those header fields.
Otherwise, the sender MUST generate all of the representation header
fields that would have been sent in a 200 (OK) response
to the same request.
</t>
<t>
A 206 response is cacheable unless otherwise indicated by
explicit cache controls (see Section 4.2.2 of <xref target="Part6"/>).
</t>
</section>
<section title="Content-Range" anchor="header.content-range">
<iref primary="true" item="Content-Range header field"/>
<t>
The "Content-Range" header field is sent in a single part
<xref target="status.206" format="none">206 (Partial Content)</xref> response to indicate the partial range
of the selected representation enclosed as the message payload, sent in
each part of a multipart 206 response to indicate the range enclosed within
each body part, and sent in <xref target="status.416" format="none">416 (Range Not Satisfiable)</xref>
responses to provide information about the selected representation.
</t>
<figure><iref primary="true" item="Grammar" subitem="Content-Range"/><iref primary="true" item="Grammar" subitem="byte-content-range"/><iref primary="true" item="Grammar" subitem="byte-range-resp"/><iref primary="true" item="Grammar" subitem="byte-range"/><iref primary="true" item="Grammar" subitem="unsatisfied-range"/><iref primary="true" item="Grammar" subitem="other-content-range"/><iref primary="true" item="Grammar" subitem="other-range-resp"/><iref primary="true" item="Grammar" subitem="complete-length"/><artwork type="abnf2616"><![CDATA[
Content-Range = byte-content-range
/ other-content-range
byte-content-range = bytes-unit SP
( byte-range-resp / unsatisfied-range )
byte-range-resp = byte-range "/" ( complete-length / "*" )
byte-range = first-byte-pos "-" last-byte-pos
unsatisfied-range = "*/" complete-length
complete-length = 1*DIGIT
other-content-range = other-range-unit SP other-range-resp
other-range-resp = *CHAR
]]></artwork></figure>
<t>
If a <xref target="status.206" format="none">206 (Partial Content)</xref> response contains a
<xref target="header.content-range" format="none">Content-Range</xref> header field with a <xref target="range.units" format="none">range unit</xref>
(<xref target="range.units"/>) that the recipient does not understand, the
recipient MUST NOT attempt to recombine it with a stored representation.
A proxy that receives such a message SHOULD forward it downstream.
</t>
<t>
For byte ranges, a sender SHOULD indicate the complete length of the
representation from which the range has been extracted, unless the complete
length is unknown or difficult to determine. An asterisk character ("*") in
place of the complete-length indicates that the representation length was
unknown when the header field was generated.
</t>
<t>
The following example illustrates when the complete length of the selected
representation is known by the sender to be 1234 bytes:
</t>
<figure><artwork type="example"><![CDATA[
Content-Range: bytes 42-1233/1234
]]></artwork></figure>
<t>
and this second example illustrates when the complete length is unknown:
</t>
<figure><artwork type="example"><![CDATA[
Content-Range: bytes 42-1233/*
]]></artwork></figure>
<t>
A Content-Range field value is invalid if it contains a
<xref target="header.content-range" format="none">byte-range-resp</xref> that has a <xref target="rule.ranges-specifier" format="none">last-byte-pos</xref>
value less than its <xref target="rule.ranges-specifier" format="none">first-byte-pos</xref> value, or a
<xref target="header.content-range" format="none">complete-length</xref> value less than or equal to its
<xref target="rule.ranges-specifier" format="none">last-byte-pos</xref> value. The recipient of an invalid
<xref target="header.content-range" format="none">Content-Range</xref> MUST NOT attempt to recombine the received
content with a stored representation.
</t>
<t>
A server generating a <xref target="status.416" format="none">416 (Range Not Satisfiable)</xref> response
to a byte range request SHOULD send a Content-Range header field with an
<xref target="header.content-range" format="none">unsatisfied-range</xref> value, as in the following example:
</t>
<figure><artwork type="example"><![CDATA[
Content-Range: bytes */1234
]]></artwork></figure>
<t>
The complete-length in a 416 response indicates the current length of the
selected representation.
</t>
<t>
The "Content-Range" header field has no meaning for status codes that do
not explicitly describe its semantic. For this specification, only the
<xref target="status.206" format="none">206 (Partial Content)</xref> and
<xref target="status.416" format="none">416 (Range Not Satisfiable)</xref> status codes describe a meaning
for Content-Range.
</t>
<t>
The following are examples of Content-Range values in which the
selected representation contains a total of 1234 bytes:
<list style="symbols">
<t>
The first 500 bytes:
<figure><artwork type="example"><![CDATA[
Content-Range: bytes 0-499/1234
]]></artwork></figure>
</t>
<t>
The second 500 bytes:
<figure><artwork type="example"><![CDATA[
Content-Range: bytes 500-999/1234
]]></artwork></figure>
</t>
<t>
All except for the first 500 bytes:
<figure><artwork type="example"><![CDATA[
Content-Range: bytes 500-1233/1234
]]></artwork></figure>
</t>
<t>
The last 500 bytes:
<figure><artwork type="example"><![CDATA[
Content-Range: bytes 734-1233/1234
]]></artwork></figure>
</t>
</list>
</t>
</section>
<section title="Combining Ranges" anchor="combining.byte.ranges">
<t>
A response might transfer only a subrange of a representation if the
connection closed prematurely or if the request used one or more Range
specifications. After several such transfers, a client might have
received several ranges of the same representation. These ranges can only
be safely combined if they all have in common the same strong validator
(Section 2.1 of <xref target="Part4"/>).
</t>
<t>
A client that has received multiple partial responses to GET requests on a
target resource MAY combine those responses into a larger continuous
range if they share the same strong validator.
</t>
<t>
If the most recent response is an incomplete 200 (OK)
response, then the header fields of that response are used for any
combined response and replace those of the matching stored responses.
</t>
<t>
If the most recent response is a <xref target="status.206" format="none">206 (Partial Content)</xref>
response and at least one of the matching stored responses is a
200 (OK), then the combined response header fields consist
of the most recent 200 response's header fields. If all of the matching
stored responses are 206 responses, then the stored response with the most
recent header fields is used as the source of header fields for the
combined response, except that the client MUST use other header fields
provided in the new response, aside from <xref target="header.content-range" format="none">Content-Range</xref>, to
replace all instances of the corresponding header fields in the stored
response.
</t>
<t>
The combined response message body consists of the union of partial
content ranges in the new response and each of the selected responses.
If the union consists of the entire range of the representation, then the
client MUST process the combined response as if it were a complete
200 (OK) response, including a Content-Length
header field that reflects the complete length.
Otherwise, the client MUST process the set of continuous ranges as one of
the following:
an incomplete 200 (OK) response if the combined response is
a prefix of the representation,
a single <xref target="status.206" format="none">206 (Partial Content)</xref> response containing a
multipart/byteranges body, or
multiple <xref target="status.206" format="none">206 (Partial Content)</xref> responses, each with one
continuous range that is indicated by a <xref target="header.content-range" format="none">Content-Range</xref> header
field.
</t>
</section>
<section title="416 Range Not Satisfiable" anchor="status.416">
<iref primary="true" item="416 Range Not Satisfiable (status code)"/>
<t>
The 416 (Range Not Satisfiable) status code indicates that
none of the ranges in the request's <xref target="header.range" format="none">Range</xref> header field
(<xref target="header.range"/>) overlap the current extent of the selected
resource or that the set of ranges requested has been rejected due to
invalid ranges or an excessive request of small or overlapping ranges.
</t>
<t>
For byte ranges, failing to overlap the current extent means that the
<xref target="rule.ranges-specifier" format="none">first-byte-pos</xref> of all of the <xref target="rule.ranges-specifier" format="none">byte-range-spec</xref>
values were greater than the current length of the selected representation.
When this status code is generated in response to a byte range request, the
sender SHOULD generate a <xref target="header.content-range" format="none">Content-Range</xref> header field
specifying the current length of the selected representation
(<xref target="header.content-range"/>).
</t>
<figure>
<preamble>For example:</preamble>
<artwork type="message/http; msgtype="response""><![CDATA[
HTTP/1.1 416 Range Not Satisfiable
Date: Fri, 20 Jan 2012 15:41:54 GMT
Content-Range: bytes */47022
]]></artwork></figure>
<t><list>
<t>
Note: Because servers are free to ignore <xref target="header.range" format="none">Range</xref>, many
implementations will simply respond with the entire selected representation
in a 200 (OK) response. That is partly because
most clients are prepared to receive a 200 (OK) to
complete the task (albeit less efficiently) and partly because clients
might not stop making an invalid partial request until they have received
a complete representation. Thus, clients cannot depend on receiving a
<xref target="status.416" format="none">416 (Range Not Satisfiable)</xref> response even when it is most
appropriate.
</t>
</list></t>
</section>
</section>
<section title="IANA Considerations" anchor="IANA.considerations">
<section title="Range Unit Registry" anchor="range.unit.registry">
<t>
The HTTP Range Unit Registry defines the name space for the range
unit names and refers to their corresponding specifications.
The registry will be created and maintained at
<eref target="http://www.iana.org/assignments/http-parameters"/>.
</t>
<section title="Procedure" anchor="range.unit.registry.procedure">
<t>
Registration of an HTTP Range Unit MUST include the following fields:
<list style="symbols">
<t>Name</t>
<t>Description</t>
<t>Pointer to specification text</t>
</list>
</t>
<t>
Values to be added to this name space require IETF Review
(see <xref target="RFC5226"/>, Section 4.1).
</t>
</section>
<section title="Registrations" anchor="range.unit.registration">
<t>
The initial HTTP Range Unit Registry shall contain the registrations
below:
</t>
<texttable align="left" suppress-title="true" anchor="iana.range.units.table">
<ttcol>Range Unit Name</ttcol>
<ttcol>Description</ttcol>
<ttcol>Reference</ttcol>
<c>bytes</c>
<c>a range of octets</c>
<c><xref target="byte.ranges"/></c>
<c>none</c>
<c>reserved as keyword, indicating no ranges are supported</c>
<c><xref target="header.accept-ranges"/></c>
</texttable>
<t>
The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
</t>
</section>
</section>
<section title="Status Code Registration" anchor="status.code.registration">
<t>
The HTTP Status Code Registry located at <eref target="http://www.iana.org/assignments/http-status-codes"/>
shall be updated with the registrations below:
</t>
<!--AUTOGENERATED FROM extract-status-code-defs.xslt, do not edit manually-->
<texttable align="left" suppress-title="true" anchor="iana.status.code.registration.table">
<ttcol>Value</ttcol>
<ttcol>Description</ttcol>
<ttcol>Reference</ttcol>
<c>206</c>
<c>Partial Content</c>
<c>
<xref target="status.206"/>
</c>
<c>416</c>
<c>Range Not Satisfiable</c>
<c>
<xref target="status.416"/>
</c>
</texttable>
<!--(END)-->
</section>
<section title="Header Field Registration" anchor="header.field.registration">
<t>
HTTP header fields are registered within the Message Header Field Registry
maintained at
<eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/>.
</t>
<t>
This document defines the following HTTP header fields, so their
associated registry entries shall be updated according to the permanent
registrations below (see <xref target="BCP90"/>):
</t>
<!--AUTOGENERATED FROM extract-header-defs.xslt, do not edit manually-->
<texttable align="left" suppress-title="true" anchor="iana.header.registration.table">
<ttcol>Header Field Name</ttcol>
<ttcol>Protocol</ttcol>
<ttcol>Status</ttcol>
<ttcol>Reference</ttcol>
<c>Accept-Ranges</c>
<c>http</c>
<c>standard</c>
<c>
<xref target="header.accept-ranges"/>
</c>
<c>Content-Range</c>
<c>http</c>
<c>standard</c>
<c>
<xref target="header.content-range"/>
</c>
<c>If-Range</c>
<c>http</c>
<c>standard</c>
<c>
<xref target="header.if-range"/>
</c>
<c>Range</c>
<c>http</c>
<c>standard</c>
<c>
<xref target="header.range"/>
</c>
</texttable>
<!--(END)-->
<t>
The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".
</t>
</section>
</section>
<section title="Security Considerations" anchor="security.considerations">
<t>
This section is meant to inform developers, information providers, and
users of known security concerns specific to the HTTP/1.1 range
request mechanisms. More general security considerations are addressed
in HTTP messaging <xref target="Part1"/> and semantics <xref target="Part2"/>.
</t>
<section title="Denial of Service Attacks using Range" anchor="overlapping.ranges">
<t>
Unconstrained multiple range requests are susceptible to denial of service
attacks because the effort required to request many overlapping ranges of
the same data is tiny compared to the time, memory, and bandwidth consumed
by attempting to serve the requested data in many parts.
Servers ought to ignore, coalesce, or reject egregious range requests, such
as requests for more than two overlapping ranges or for many small ranges
in a single set, particularly when the ranges are requested out of order
for no apparent reason. Multipart range requests are not designed to
support random access.
</t>
</section>
</section>
<section title="Acknowledgments" anchor="acks">
<t>
See Section 10 of <xref target="Part1"/>.
</t>
</section>
</middle>
<back>
<references title="Normative References">
<reference anchor="Part1">
<front>
<title>Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing</title>
<author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
<organization abbrev="Adobe">Adobe Systems Incorporated</organization>
<address><email>fielding@gbiv.com</email></address>
</author>
<author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
<organization abbrev="greenbytes">greenbytes GmbH</organization>
<address><email>julian.reschke@greenbytes.de</email></address>
</author>
<date month="September" year="2013"/>
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p1-messaging-24"/>
</reference>
<reference anchor="Part2">
<front>
<title>Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content</title>
<author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
<organization abbrev="Adobe">Adobe Systems Incorporated</organization>
<address><email>fielding@gbiv.com</email></address>
</author>
<author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
<organization abbrev="greenbytes">greenbytes GmbH</organization>
<address><email>julian.reschke@greenbytes.de</email></address>
</author>
<date month="September" year="2013"/>
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p2-semantics-24"/>
</reference>
<reference anchor="Part4">
<front>
<title>Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests</title>
<author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
<organization abbrev="Adobe">Adobe Systems Incorporated</organization>
<address><email>fielding@gbiv.com</email></address>
</author>
<author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
<organization abbrev="greenbytes">greenbytes GmbH</organization>
<address><email>julian.reschke@greenbytes.de</email></address>
</author>
<date month="September" year="2013"/>
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p4-conditional-24"/>
</reference>
<reference anchor="Part6">
<front>
<title>Hypertext Transfer Protocol (HTTP/1.1): Caching</title>
<author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">
<organization abbrev="Adobe">Adobe Systems Incorporated</organization>
<address><email>fielding@gbiv.com</email></address>
</author>
<author initials="M." surname="Nottingham" fullname="Mark Nottingham" role="editor">
<organization>Akamai</organization>
<address><email>mnot@mnot.net</email></address>
</author>
<author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">
<organization abbrev="greenbytes">greenbytes GmbH</organization>
<address><email>julian.reschke@greenbytes.de</email></address>
</author>
<date month="September" year="2013"/>
</front>
<seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-24"/>
</reference>
<reference anchor="RFC2046">
<front>
<title abbrev="Media Types">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</title>
<author initials="N." surname="Freed" fullname="Ned Freed">
<organization>Innosoft International, Inc.</organization>
<address><email>ned@innosoft.com</email></address>
</author>
<author initials="N." surname="Borenstein" fullname="Nathaniel S. Borenstein">
<organization>First Virtual Holdings</organization>
<address><email>nsb@nsb.fv.com</email></address>
</author>
<date month="November" year="1996"/>
</front>
<seriesInfo name="RFC" value="2046"/>
</reference>
<reference anchor="RFC2119">
<front>
<title>Key words for use in RFCs to Indicate Requirement Levels</title>
<author initials="S." surname="Bradner" fullname="Scott Bradner">
<organization>Harvard University</organization>
<address><email>sob@harvard.edu</email></address>
</author>
<date month="March" year="1997"/>
</front>
<seriesInfo name="BCP" value="14"/>
<seriesInfo name="RFC" value="2119"/>
</reference>
<reference anchor="RFC5234">
<front>
<title abbrev="ABNF for Syntax Specifications">Augmented BNF for Syntax Specifications: ABNF</title>
<author initials="D." surname="Crocker" fullname="Dave Crocker" role="editor">
<organization>Brandenburg InternetWorking</organization>
<address>
<email>dcrocker@bbiw.net</email>
</address>
</author>
<author initials="P." surname="Overell" fullname="Paul Overell">
<organization>THUS plc.</organization>
<address>
<email>paul.overell@thus.net</email>
</address>
</author>
<date month="January" year="2008"/>
</front>
<seriesInfo name="STD" value="68"/>
<seriesInfo name="RFC" value="5234"/>
</reference>
</references>
<references title="Informative References">
<reference anchor="RFC2616">
<front>
<title>Hypertext Transfer Protocol -- HTTP/1.1</title>
<author initials="R." surname="Fielding" fullname="R. Fielding">
<organization>University of California, Irvine</organization>
<address><email>fielding@ics.uci.edu</email></address>
</author>
<author initials="J." surname="Gettys" fullname="J. Gettys">
<organization>W3C</organization>
<address><email>jg@w3.org</email></address>
</author>
<author initials="J." surname="Mogul" fullname="J. Mogul">
<organization>Compaq Computer Corporation</organization>
<address><email>mogul@wrl.dec.com</email></address>
</author>
<author initials="H." surname="Frystyk" fullname="H. Frystyk">
<organization>MIT Laboratory for Computer Science</organization>
<address><email>frystyk@w3.org</email></address>
</author>
<author initials="L." surname="Masinter" fullname="L. Masinter">
<organization>Xerox Corporation</organization>
<address><email>masinter@parc.xerox.com</email></address>
</author>
<author initials="P." surname="Leach" fullname="P. Leach">
<organization>Microsoft Corporation</organization>
<address><email>paulle@microsoft.com</email></address>
</author>
<author initials="T." surname="Berners-Lee" fullname="T. Berners-Lee">
<organization>W3C</organization>
<address><email>timbl@w3.org</email></address>
</author>
<date month="June" year="1999"/>
</front>
<seriesInfo name="RFC" value="2616"/>
</reference>
<reference anchor="BCP90">
<front>
<title>Registration Procedures for Message Header Fields</title>
<author initials="G." surname="Klyne" fullname="G. Klyne">
<organization>Nine by Nine</organization>
<address><email>GK-IETF@ninebynine.org</email></address>
</author>
<author initials="M." surname="Nottingham" fullname="M. Nottingham">
<organization>BEA Systems</organization>
<address><email>mnot@pobox.com</email></address>
</author>
<author initials="J." surname="Mogul" fullname="J. Mogul">
<organization>HP Labs</organization>
<address><email>JeffMogul@acm.org</email></address>
</author>
<date year="2004" month="September"/>
</front>
<seriesInfo name="BCP" value="90"/>
<seriesInfo name="RFC" value="3864"/>
</reference>
<reference anchor="BCP13">
<front>
<title>Media Type Specifications and Registration Procedures</title>
<author initials="N." surname="Freed" fullname="Ned Freed">
<organization>Oracle</organization>
<address>
<email>ned+ietf@mrochek.com</email>
</address>
</author>
<author initials="J." surname="Klensin" fullname="John C. Klensin">
<address>
<email>john+ietf@jck.com</email>
</address>
</author>
<author initials="T." surname="Hansen" fullname="Tony Hansen">
<organization>AT&T Laboratories</organization>
<address>
<email>tony+mtsuffix@maillennium.att.com</email>
</address>
</author>
<date year="2013" month="January"/>
</front>
<seriesInfo name="BCP" value="13"/>
<seriesInfo name="RFC" value="6838"/>
</reference>
<reference anchor="RFC5226">
<front>
<title>Guidelines for Writing an IANA Considerations Section in RFCs</title>
<author initials="T." surname="Narten" fullname="T. Narten">
<organization>IBM</organization>
<address><email>narten@us.ibm.com</email></address>
</author>
<author initials="H." surname="Alvestrand" fullname="H. Alvestrand">
<organization>Google</organization>
<address><email>Harald@Alvestrand.no</email></address>
</author>
<date year="2008" month="May"/>
</front>
<seriesInfo name="BCP" value="26"/>
<seriesInfo name="RFC" value="5226"/>
</reference>
</references>
<section title="Internet Media Type multipart/byteranges" anchor="internet.media.type.multipart.byteranges">
<iref item="Media Type" subitem="multipart/byteranges" primary="true"/>
<iref item="multipart/byteranges Media Type" primary="true"/>
<t>
When a <xref target="status.206" format="none">206 (Partial Content)</xref> response message includes the
content of multiple ranges, they are transmitted as body parts in a
multipart message body (<xref target="RFC2046"/>, Section 5.1)
with the media type of "multipart/byteranges". The following definition is
to be registered with IANA <xref target="BCP13"/>.
</t>
<t>
The multipart/byteranges media type includes one or more body parts, each
with its own Content-Type and <xref target="header.content-range" format="none">Content-Range</xref>
fields. The required boundary parameter specifies the boundary string used
to separate each body part.
</t>
<t>
<list style="hanging">
<t hangText="Type name:">
multipart
</t>
<t hangText="Subtype name:">
byteranges
</t>
<t hangText="Required parameters:">
boundary
</t>
<t hangText="Optional parameters:">
none
</t>
<t hangText="Encoding considerations:">
only "7bit", "8bit", or "binary" are permitted
</t>
<t hangText="Security considerations:">
none
</t>
<t hangText="Interoperability considerations:">
none
</t>
<t hangText="Published specification:">
This specification (see <xref target="internet.media.type.multipart.byteranges"/>).
</t>
<t hangText="Applications that use this media type:">
HTTP components supporting multiple ranges in a single request.
</t>
<t hangText="Additional information:">
<list style="hanging">
<t hangText="Magic number(s):">none</t>
<t hangText="File extension(s):">none</t>
<t hangText="Macintosh file type code(s):">none</t>
</list>
</t>
<t hangText="Person and email address to contact for further information:">
See Authors Section.
</t>
<t hangText="Intended usage:">
COMMON
</t>
<t hangText="Restrictions on usage:">
none
</t>
<t hangText="Author:">
See Authors Section.
</t>
<t hangText="Change controller:">
IESG
</t>
</list>
</t>
<t>
Implementation Notes:
<list style="numbers">
<t>Additional CRLFs might precede the first boundary string in the body.</t>
<t>Although <xref target="RFC2046"/> permits the boundary string to be
quoted, some existing implementations handle a quoted boundary
string incorrectly.</t>
<t>A number of clients and servers were coded to an early draft
of the byteranges specification that used a media type of
multipart/x-byteranges<iref item="multipart/x-byteranges Media Type"/><iref item="Media Type" subitem="multipart/x-byteranges"/>,
which is almost (but not quite) compatible with this type.</t>
</list>
</t>
<t>
Despite the name, the "multipart/byteranges" media type is not limited to
byte ranges. The following example uses an "exampleunit" range unit:
</t>
<figure><artwork type="message/http; msgtype="response""><![CDATA[
HTTP/1.1 206 Partial Content
Date: Tue, 14 Nov 1995 06:25:24 GMT
Last-Modified: Tue, 14 July 04:58:08 GMT
Content-Length: 2331785
Content-Type: multipart/byteranges; boundary=THIS_STRING_SEPARATES
--THIS_STRING_SEPARATES
Content-Type: video/example
Content-Range: exampleunit 1.2-4.3/25
...the first range...
--THIS_STRING_SEPARATES
Content-Type: video/example
Content-Range: exampleunit 11.2-14.3/25
...the second range
--THIS_STRING_SEPARATES--
]]></artwork>
</figure>
</section>
<section title="Changes from RFC 2616" anchor="changes.from.rfc.2616">
<t>
Servers are given more leeway in how they respond to a range request,
in order to mitigate abuse by malicious (or just greedy) clients.
(<xref target="header.range"/>)
</t>
<t>
A weak validator cannot be used in a <xref target="status.206" format="none">206</xref> response.
(<xref target="status.206"/>)
</t>
<t>
The Content-Range header field only has meaning when the status code
explicitly defines its use.
(<xref target="header.content-range"/>)
</t>
<t>
This specification introduces a Range Unit Registry.
(<xref target="range.unit.registry"/>)
</t>
<t>
multipart/byteranges can consist of a single part.
(<xref target="internet.media.type.multipart.byteranges"/>)
</t>
</section>
<section title="Imported ABNF" anchor="imported.abnf">
<t>
The following core rules are included by
reference, as defined in Appendix B.1 of <xref target="RFC5234"/>:
ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls),
DIGIT (decimal 0-9), DQUOTE (double quote),
HEXDIG (hexadecimal 0-9/A-F/a-f), LF (line feed),
OCTET (any 8-bit sequence of data), SP (space), and
VCHAR (any visible US-ASCII character).
</t>
<t>
Note that all rules derived from <xref target="imported.abnf" format="none">token</xref> are to
be compared case-insensitively, like <xref target="range.units" format="none">range-unit</xref> and
<xref target="header.accept-ranges" format="none">acceptable-ranges</xref>.
</t>
<t>
The rules below are defined in <xref target="Part1"/>:
</t>
<figure><artwork type="abnf2616"><![CDATA[
OWS = <OWS, defined in [Part1], Section 3.2.3>
token = <token, defined in [Part1], Section 3.2.6>
]]></artwork></figure>
<t>
The rules below are defined in other parts:
</t>
<figure><artwork type="abnf2616"><![CDATA[
HTTP-date = <HTTP-date, defined in [Part2], Section 7.1.1.1>
entity-tag = <entity-tag, defined in [Part4], Section 2.3>
]]></artwork></figure>
</section>
<section title="Collected ABNF" anchor="collected.abnf">
<t>
In the collected ABNF below, list rules are expanded as per Section 1.2 of <xref target="Part1"/>.
</t><figure>
<artwork type="abnf" name="p5-range.parsed-abnf"><![CDATA[
Accept-Ranges = acceptable-ranges
Content-Range = byte-content-range / other-content-range
HTTP-date = <HTTP-date, defined in [Part2], Section 7.1.1.1>
If-Range = entity-tag / HTTP-date
OWS = <OWS, defined in [Part1], Section 3.2.3>
Range = byte-ranges-specifier / other-ranges-specifier
acceptable-ranges = ( *( "," OWS ) range-unit *( OWS "," [ OWS
range-unit ] ) ) / "none"
byte-content-range = bytes-unit SP ( byte-range-resp /
unsatisfied-range )
byte-range = first-byte-pos "-" last-byte-pos
byte-range-resp = byte-range "/" ( complete-length / "*" )
byte-range-set = *( "," OWS ) ( byte-range-spec /
suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
suffix-byte-range-spec ) ] )
byte-range-spec = first-byte-pos "-" [ last-byte-pos ]
byte-ranges-specifier = bytes-unit "=" byte-range-set
bytes-unit = "bytes"
complete-length = 1*DIGIT
entity-tag = <entity-tag, defined in [Part4], Section 2.3>
first-byte-pos = 1*DIGIT
last-byte-pos = 1*DIGIT
other-content-range = other-range-unit SP other-range-resp
other-range-resp = *CHAR
other-range-set = 1*CHAR
other-range-unit = token
other-ranges-specifier = other-range-unit "=" other-range-set
range-unit = bytes-unit / other-range-unit
suffix-byte-range-spec = "-" suffix-length
suffix-length = 1*DIGIT
token = <token, defined in [Part1], Section 3.2.6>
unsatisfied-range = "*/" complete-length
]]></artwork>
</figure>
</section>
<section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log">
<t>
Changes up to the first Working Group Last Call draft are summarized
in <eref target="http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-19#appendix-D"/>.
</t>
<section title="Since draft-ietf-httpbis-p5-range-19" anchor="changes.since.19">
<t>
Closed issues:
<list style="symbols">
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/358"/>:
"ABNF list expansion code problem"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/361"/>:
"ABNF requirements for recipients"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/367"/>:
"reserve 'none' as byte range unit"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/368"/>:
"note introduction of new IANA registries as normative changes"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/369"/>:
"range units vs leading zeroes vs size"
</t>
</list>
</t>
</section>
<section title="Since draft-ietf-httpbis-p5-range-20" anchor="changes.since.20">
<t>
<list style="symbols">
<t>
Conformance criteria and considerations regarding error handling are
now defined in Part 1.
</t>
</list>
</t>
</section>
<section title="Since draft-ietf-httpbis-p5-range-21" anchor="changes.since.21">
<t>
Closed issues:
<list style="symbols">
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/175"/>:
"Security consideration: range flooding"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/223"/>:
"Allowing heuristic caching for new status codes"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/311"/>:
"Add limitations to Range to reduce its use as a denial-of-service tool"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/407"/>:
"416 and multipart/byteranges"
</t>
</list>
</t>
</section>
<section title="Since draft-ietf-httpbis-p5-range-22" anchor="changes.since.22">
<t>
Closed issues:
<list style="symbols">
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/436"/>:
"explain list expansion in ABNF appendices"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/437"/>:
"incorrect example dates"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/438"/>:
"media type registration template issues"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/462"/>:
"Editorial suggestions"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/485"/>:
"MUSTs and other feedback"
</t>
</list>
</t>
</section>
<section title="Since draft-ietf-httpbis-p5-range-23" anchor="changes.since.23">
<t>
Closed issues:
<list style="symbols">
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/489"/>:
"is P5's definition of strong validator consistent with P4?"
</t>
<t>
<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/490"/>:
"p5 editorial comments"
</t>
</list>
</t>
</section>
</section>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 18:34:58 |