rfc7233.txt   draft-ietf-httpbis-range-00.txt 
Internet Engineering Task Force (IETF) R. Fielding, Ed. HTTP Working Group R. Fielding, Ed.
Request for Comments: 7233 Adobe Internet-Draft Adobe
Obsoletes: 2616 Y. Lafon, Ed. Obsoletes: 7233 (if approved) M. Nottingham, Ed.
Category: Standards Track W3C Intended status: Standards Track Fastly
ISSN: 2070-1721 J. Reschke, Ed. Expires: October 5, 2018 J. Reschke, Ed.
greenbytes greenbytes
June 2014 April 3, 2018
Hypertext Transfer Protocol (HTTP/1.1): Range Requests Hypertext Transfer Protocol (HTTP): Range Requests
draft-ietf-httpbis-range-00
Abstract Abstract
The Hypertext Transfer Protocol (HTTP) is a stateless application- The Hypertext Transfer Protocol (HTTP) is a stateless application-
level protocol for distributed, collaborative, hypertext information level protocol for distributed, collaborative, hypertext information
systems. This document defines range requests and the rules for systems. This document defines range requests and the rules for
constructing and combining responses to those requests. constructing and combining responses to those requests.
This document obsoletes RFC 7233.
Editorial Note
This note is to be removed before publishing as an RFC.
Discussion of this draft takes place on the HTTP working group
mailing list (ietf-http-wg@w3.org), which is archived at
<http://lists.w3.org/Archives/Public/ietf-http-wg/>.
Working Group information can be found at <http://httpwg.github.io/>;
source code and issues list for this draft can be found at
<https://github.com/httpwg/http-core>.
The changes in this draft are summarized in Appendix E.1.
Status of This Memo Status of This Memo
This is an Internet Standards Track document. This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
This document is a product of the Internet Engineering Task Force Internet-Drafts are working documents of the Internet Engineering
(IETF). It represents the consensus of the IETF community. It has Task Force (IETF). Note that other groups may also distribute
received public review and has been approved for publication by the working documents as Internet-Drafts. The list of current Internet-
Internet Engineering Steering Group (IESG). Further information on Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata, Internet-Drafts are draft documents valid for a maximum of six months
and how to provide feedback on it may be obtained at and may be updated, replaced, or obsoleted by other documents at any
http://www.rfc-editor.org/info/rfc7233. time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 5, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
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carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
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described in the Simplified BSD License. described in the Simplified BSD License.
This document may contain material from IETF Documents or IETF This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this 10, 2008. The person(s) controlling the copyright in some of this
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modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Table of Contents Table of Contents
1. Introduction ....................................................4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conformance and Error Handling .............................4 1.1. Conformance and Error Handling . . . . . . . . . . . . . 4
1.2. Syntax Notation ............................................4 1.2. Syntax Notation . . . . . . . . . . . . . . . . . . . . . 4
2. Range Units .....................................................5 2. Range Units . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Byte Ranges ................................................5 2.1. Byte Ranges . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Other Range Units ..........................................7 2.2. Other Range Units . . . . . . . . . . . . . . . . . . . . 6
2.3. Accept-Ranges ..............................................7 2.3. Accept-Ranges . . . . . . . . . . . . . . . . . . . . . . 6
3. Range Requests ..................................................8 3. Range Requests . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Range ......................................................8 3.1. Range . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. If-Range ...................................................9 3.2. If-Range . . . . . . . . . . . . . . . . . . . . . . . . 8
4. Responses to a Range Request ...................................10 4. Responses to a Range Request . . . . . . . . . . . . . . . . 9
4.1. 206 Partial Content .......................................10 4.1. 206 Partial Content . . . . . . . . . . . . . . . . . . . 9
4.2. Content-Range .............................................12 4.2. Content-Range . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Combining Ranges ..........................................14 4.3. Combining Ranges . . . . . . . . . . . . . . . . . . . . 13
4.4. 416 Range Not Satisfiable .................................15 4.4. 416 Range Not Satisfiable . . . . . . . . . . . . . . . . 14
5. IANA Considerations ............................................16 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
5.1. Range Unit Registry .......................................16 5.1. Range Unit Registry . . . . . . . . . . . . . . . . . . . 15
5.1.1. Procedure ..........................................16 5.1.1. Procedure . . . . . . . . . . . . . . . . . . . . . . 15
5.1.2. Registrations ......................................16 5.1.2. Registrations . . . . . . . . . . . . . . . . . . . . 15
5.2. Status Code Registration ..................................17 5.2. Status Code Registration . . . . . . . . . . . . . . . . 16
5.3. Header Field Registration .................................17 5.3. Header Field Registration . . . . . . . . . . . . . . . . 16
5.4. Internet Media Type Registration ..........................17 5.4. Internet Media Type Registration . . . . . . . . . . . . 16
5.4.1. Internet Media Type multipart/byteranges ...........18 5.4.1. Internet Media Type multipart/byteranges . . . . . . 16
6. Security Considerations ........................................19 6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6.1. Denial-of-Service Attacks Using Range .....................19 6.1. Denial-of-Service Attacks Using Range . . . . . . . . . . 18
7. Acknowledgments ................................................19 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
8. References .....................................................20 7.1. Normative References . . . . . . . . . . . . . . . . . . 18
8.1. Normative References ......................................20 7.2. Informative References . . . . . . . . . . . . . . . . . 19
8.2. Informative References ....................................20 Appendix A. Internet Media Type multipart/byteranges . . . . . . 20
Appendix A. Internet Media Type multipart/byteranges ..............21 Appendix B. Changes from RFC 7233 . . . . . . . . . . . . . . . 21
Appendix B. Changes from RFC 2616 .................................22 Appendix C. Imported ABNF . . . . . . . . . . . . . . . . . . . 21
Appendix C. Imported ABNF .........................................22 Appendix D. Collected ABNF . . . . . . . . . . . . . . . . . . . 21
Appendix D. Collected ABNF ........................................23 Appendix E. Change Log . . . . . . . . . . . . . . . . . . . . . 23
Index .............................................................24 E.1. Since RFC 7233 . . . . . . . . . . . . . . . . . . . . . 23
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
Hypertext Transfer Protocol (HTTP) clients often encounter Hypertext Transfer Protocol (HTTP) clients often encounter
interrupted data transfers as a result of canceled requests or interrupted data transfers as a result of canceled requests or
dropped connections. When a client has stored a partial dropped connections. When a client has stored a partial
representation, it is desirable to request the remainder of that representation, it is desirable to request the remainder of that
representation in a subsequent request rather than transfer the representation in a subsequent request rather than transfer the
entire representation. Likewise, devices with limited local storage entire representation. Likewise, devices with limited local storage
might benefit from being able to request only a subset of a larger might benefit from being able to request only a subset of a larger
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feature (or not supporting it for the target resource) can respond as feature (or not supporting it for the target resource) can respond as
if it is a normal GET request without impacting interoperability. if it is a normal GET request without impacting interoperability.
Partial responses are indicated by a distinct status code to not be Partial responses are indicated by a distinct status code to not be
mistaken for full responses by caches that might not implement the mistaken for full responses by caches that might not implement the
feature. feature.
Although the range request mechanism is designed to allow for Although the range request mechanism is designed to allow for
extensible range types, this specification only defines requests for extensible range types, this specification only defines requests for
byte ranges. byte ranges.
This specification obsoletes RFC 7233, with the changes being
summarized in Appendix B.
1.1. Conformance and Error Handling 1.1. Conformance and Error Handling
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Conformance criteria and considerations regarding error handling are Conformance criteria and considerations regarding error handling are
defined in Section 2.5 of [RFC7230]. defined in Section 2.5 of [MESSGNG].
1.2. Syntax Notation 1.2. Syntax Notation
This specification uses the Augmented Backus-Naur Form (ABNF) This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234] with a list extension, defined in Section 7 of notation of [RFC5234] with a list extension, defined in Section 7 of
[RFC7230], that allows for compact definition of comma-separated [MESSGNG], that allows for compact definition of comma-separated
lists using a '#' operator (similar to how the '*' operator indicates lists using a '#' operator (similar to how the '*' operator indicates
repetition). Appendix C describes rules imported from other repetition). Appendix C describes rules imported from other
documents. Appendix D shows the collected grammar with all list documents. Appendix D shows the collected grammar with all list
operators expanded to standard ABNF notation. operators expanded to standard ABNF notation.
2. Range Units 2. Range Units
A representation can be partitioned into subranges according to A representation can be partitioned into subranges according to
various structural units, depending on the structure inherent in the various structural units, depending on the structure inherent in the
representation's media type. This "range unit" is used in the representation's media type. This "range unit" is used in the
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field to delineate the parts of a representation that are requested, field to delineate the parts of a representation that are requested,
and the Content-Range (Section 4.2) payload header field to describe and the Content-Range (Section 4.2) payload header field to describe
which part of a representation is being transferred. which part of a representation is being transferred.
range-unit = bytes-unit / other-range-unit range-unit = bytes-unit / other-range-unit
2.1. Byte Ranges 2.1. Byte Ranges
Since representation data is transferred in payloads as a sequence of Since representation data is transferred in payloads as a sequence of
octets, a byte range is a meaningful substructure for any octets, a byte range is a meaningful substructure for any
representation transferable over HTTP (Section 3 of [RFC7231]). The representation transferable over HTTP (Section 3 of [SEMNTCS]). The
"bytes" range unit is defined for expressing subranges of the data's "bytes" range unit is defined for expressing subranges of the data's
octet sequence. octet sequence.
bytes-unit = "bytes" bytes-unit = "bytes"
A byte-range request can specify a single range of bytes or a set of A byte-range request can specify a single range of bytes or a set of
ranges within a single representation. ranges within a single representation.
byte-ranges-specifier = bytes-unit "=" byte-range-set byte-ranges-specifier = bytes-unit "=" byte-range-set
byte-range-set = 1#( byte-range-spec / suffix-byte-range-spec ) byte-range-set = 1#( byte-range-spec / suffix-byte-range-spec )
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the remainder of the representation (i.e., the server replaces the the remainder of the representation (i.e., the server replaces the
value of last-byte-pos with a value that is one less than the current value of last-byte-pos with a value that is one less than the current
length of the selected representation). length of the selected representation).
A client can request the last N bytes of the selected representation A client can request the last N bytes of the selected representation
using a suffix-byte-range-spec. using a suffix-byte-range-spec.
suffix-byte-range-spec = "-" suffix-length suffix-byte-range-spec = "-" suffix-length
suffix-length = 1*DIGIT suffix-length = 1*DIGIT
If the selected representation is shorter than the specified If the selected representation is shorter than the specified suffix-
suffix-length, the entire representation is used. length, the entire representation is used.
Additional examples, assuming a representation of length 10000: Additional examples, assuming a representation of length 10000:
o The final 500 bytes (byte offsets 9500-9999, inclusive): o The final 500 bytes (byte offsets 9500-9999, inclusive):
bytes=-500 bytes=-500
Or: Or:
bytes=9500- bytes=9500-
o The first and last bytes only (bytes 0 and 9999): o The first and last bytes only (bytes 0 and 9999):
bytes=0-0,-1 bytes=0-0,-1
o Other valid (but not canonical) specifications of the second 500 o Other valid (but not canonical) specifications of the second 500
bytes (byte offsets 500-999, inclusive): bytes (byte offsets 500-999, inclusive):
bytes=500-600,601-999 bytes=500-600,601-999
bytes=500-700,601-999 bytes=500-700,601-999
If a valid byte-range-set includes at least one byte-range-spec with If a valid byte-range-set includes at least one byte-range-spec with
a first-byte-pos that is less than the current length of the a first-byte-pos that is less than the current length of the
representation, or at least one suffix-byte-range-spec with a representation, or at least one suffix-byte-range-spec with a non-
non-zero suffix-length, then the byte-range-set is satisfiable. zero suffix-length, then the byte-range-set is satisfiable.
Otherwise, the byte-range-set is unsatisfiable. Otherwise, the byte-range-set is unsatisfiable.
In the byte-range syntax, first-byte-pos, last-byte-pos, and In the byte-range syntax, first-byte-pos, last-byte-pos, and suffix-
suffix-length are expressed as decimal number of octets. Since there length are expressed as decimal number of octets. Since there is no
is no predefined limit to the length of a payload, recipients MUST predefined limit to the length of a payload, recipients MUST
anticipate potentially large decimal numerals and prevent parsing anticipate potentially large decimal numerals and prevent parsing
errors due to integer conversion overflows. errors due to integer conversion overflows.
2.2. Other Range Units 2.2. Other Range Units
Range units are intended to be extensible. New range units ought to Range units are intended to be extensible. New range units ought to
be registered with IANA, as defined in Section 5.1. be registered with IANA, as defined in Section 5.1.
other-range-unit = token other-range-unit = token
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A client that is requesting multiple ranges SHOULD list those ranges A client that is requesting multiple ranges SHOULD list those ranges
in ascending order (the order in which they would typically be in ascending order (the order in which they would typically be
received in a complete representation) unless there is a specific received in a complete representation) unless there is a specific
need to request a later part earlier. For example, a user agent need to request a later part earlier. For example, a user agent
processing a large representation with an internal catalog of parts processing a large representation with an internal catalog of parts
might need to request later parts first, particularly if the might need to request later parts first, particularly if the
representation consists of pages stored in reverse order and the user representation consists of pages stored in reverse order and the user
agent wishes to transfer one page at a time. agent wishes to transfer one page at a time.
The Range header field is evaluated after evaluating the precondition The Range header field is evaluated after evaluating the precondition
header fields defined in [RFC7232], and only if the result in absence header fields defined in [CONDTNL], and only if the result in absence
of the Range header field would be a 200 (OK) response. In other 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 words, Range is ignored when a conditional GET would result in a 304
(Not Modified) response. (Not Modified) response.
The If-Range header field (Section 3.2) can be used as a precondition The If-Range header field (Section 3.2) can be used as a precondition
to applying the Range header field. to applying the Range header field.
If all of the preconditions are true, the server supports the Range If all of the preconditions are true, the server supports the Range
header field for the target resource, and the specified range(s) are header field for the target resource, and the specified range(s) are
valid and satisfiable (as defined in Section 2.1), the server SHOULD valid and satisfiable (as defined in Section 2.1), the server SHOULD
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representation. representation.
The "If-Range" header field allows a client to "short-circuit" the The "If-Range" header field allows a client to "short-circuit" the
second request. Informally, its meaning is as follows: if the second request. Informally, its meaning is as follows: if the
representation is unchanged, send me the part(s) that I am requesting representation is unchanged, send me the part(s) that I am requesting
in Range; otherwise, send me the entire representation. in Range; otherwise, send me the entire representation.
If-Range = entity-tag / HTTP-date If-Range = entity-tag / HTTP-date
A client MUST NOT generate an If-Range header field in a request that A client MUST NOT generate an If-Range header field in a request that
does not contain a Range header field. A server MUST ignore an does not contain a Range header field. A server MUST ignore an If-
If-Range header field received in a request that does not contain a Range header field received in a request that does not contain a
Range header field. An origin server MUST ignore an If-Range header Range header field. An origin server MUST ignore an If-Range header
field received in a request for a target resource that does not field received in a request for a target resource that does not
support Range requests. support Range requests.
A client MUST NOT generate an If-Range header field containing an 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 entity-tag that is marked as weak. A client MUST NOT generate an If-
If-Range header field containing an HTTP-date unless the client has Range header field containing an HTTP-date unless the client has no
no entity-tag for the corresponding representation and the date is a entity-tag for the corresponding representation and the date is a
strong validator in the sense defined by Section 2.2.2 of [RFC7232]. strong validator in the sense defined by Section 2.2.2 of [CONDTNL].
A server that evaluates an If-Range precondition MUST use the strong A server that evaluates an If-Range precondition MUST use the strong
comparison function when comparing entity-tags (Section 2.3.2 of comparison function when comparing entity-tags (Section 2.3.2 of
[RFC7232]) and MUST evaluate the condition as false if an HTTP-date [CONDTNL]) and MUST evaluate the condition as false if an HTTP-date
validator is provided that is not a strong validator in the sense validator is provided that is not a strong validator in the sense
defined by Section 2.2.2 of [RFC7232]. A valid entity-tag can be defined by Section 2.2.2 of [CONDTNL]. A valid entity-tag can be
distinguished from a valid HTTP-date by examining the first two distinguished from a valid HTTP-date by examining the first two
characters for a DQUOTE. characters for a DQUOTE.
If the validator given in the If-Range header field matches the If the validator given in the If-Range header field matches the
current validator for the selected representation of the target current validator for the selected representation of the target
resource, then the server SHOULD process the Range header field as resource, then the server SHOULD process the Range header field as
requested. If the validator does not match, the server MUST ignore requested. If the validator does not match, the server MUST ignore
the Range header field. Note that this comparison by exact match, the Range header field. Note that this comparison by exact match,
including when the validator is an HTTP-date, differs from the including when the validator is an HTTP-date, differs from the
"earlier than or equal to" comparison used when evaluating an "earlier than or equal to" comparison used when evaluating an If-
If-Unmodified-Since conditional. Unmodified-Since conditional.
4. Responses to a Range Request 4. Responses to a Range Request
4.1. 206 Partial Content 4.1. 206 Partial Content
The 206 (Partial Content) status code indicates that the server is The 206 (Partial Content) status code indicates that the server is
successfully fulfilling a range request for the target resource by successfully fulfilling a range request for the target resource by
transferring one or more parts of the selected representation that transferring one or more parts of the selected representation that
correspond to the satisfiable ranges found in the request's Range correspond to the satisfiable ranges found in the request's Range
header field (Section 3.1). header field (Section 3.1).
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A server MUST NOT generate a multipart response to a request for a A server MUST NOT generate a multipart response to a request for a
single range, since a client that does not request multiple parts single range, since a client that does not request multiple parts
might not support multipart responses. However, a server MAY might not support multipart responses. However, a server MAY
generate a multipart/byteranges payload with only a single body part generate a multipart/byteranges payload with only a single body part
if multiple ranges were requested and only one range was found to be if multiple ranges were requested and only one range was found to be
satisfiable or only one range remained after coalescing. A client satisfiable or only one range remained after coalescing. A client
that cannot process a multipart/byteranges response MUST NOT generate that cannot process a multipart/byteranges response MUST NOT generate
a request that asks for multiple ranges. a request that asks for multiple ranges.
When a multipart response payload is generated, the server SHOULD When a multipart response payload is generated, the server SHOULD
send the parts in the same order that the corresponding send the parts in the same order that the corresponding byte-range-
byte-range-spec appeared in the received Range header field, spec appeared in the received Range header field, excluding those
excluding those ranges that were deemed unsatisfiable or that were ranges that were deemed unsatisfiable or that were coalesced into
coalesced into other ranges. A client that receives a multipart other ranges. A client that receives a multipart response MUST
response MUST inspect the Content-Range header field present in each inspect the Content-Range header field present in each body part in
body part in order to determine which range is contained in that body order to determine which range is contained in that body part; a
part; a client cannot rely on receiving the same ranges that it client cannot rely on receiving the same ranges that it requested,
requested, nor the same order that it requested. nor the same order that it requested.
When a 206 response is generated, the server MUST generate the When a 206 response is generated, the server MUST generate the
following header fields, in addition to those required above, if 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 field would have been sent in a 200 (OK) response to the same
request: Date, Cache-Control, ETag, Expires, Content-Location, and request: Date, Cache-Control, ETag, Expires, Content-Location, and
Vary. Vary.
If a 206 is generated in response to a request with an If-Range If a 206 is generated in response to a request with an If-Range
header field, the sender SHOULD NOT generate other representation header field, the sender SHOULD NOT generate other representation
header fields beyond those required above, because the client is header fields beyond those required above, because the client is
understood to already have a prior response containing those header understood to already have a prior response containing those header
fields. Otherwise, the sender MUST generate all of the fields. Otherwise, the sender MUST generate all of the
representation header fields that would have been sent in a 200 (OK) representation header fields that would have been sent in a 200 (OK)
response to the same request. response to the same request.
A 206 response is cacheable by default; i.e., unless otherwise A 206 response is cacheable by default; i.e., unless otherwise
indicated by explicit cache controls (see Section 4.2.2 of indicated by explicit cache controls (see Section 4.2.2 of
[RFC7234]). [CACHING]).
4.2. Content-Range 4.2. Content-Range
The "Content-Range" header field is sent in a single part 206 The "Content-Range" header field is sent in a single part 206
(Partial Content) response to indicate the partial range of the (Partial Content) response to indicate the partial range of the
selected representation enclosed as the message payload, sent in each selected representation enclosed as the message payload, sent in each
part of a multipart 206 response to indicate the range enclosed part of a multipart 206 response to indicate the range enclosed
within each body part, and sent in 416 (Range Not Satisfiable) within each body part, and sent in 416 (Range Not Satisfiable)
responses to provide information about the selected representation. responses to provide information about the selected representation.
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The following example illustrates when the complete length of the The following example illustrates when the complete length of the
selected representation is known by the sender to be 1234 bytes: selected representation is known by the sender to be 1234 bytes:
Content-Range: bytes 42-1233/1234 Content-Range: bytes 42-1233/1234
and this second example illustrates when the complete length is and this second example illustrates when the complete length is
unknown: unknown:
Content-Range: bytes 42-1233/* Content-Range: bytes 42-1233/*
A Content-Range field value is invalid if it contains a A Content-Range field value is invalid if it contains a byte-range-
byte-range-resp that has a last-byte-pos value less than its resp that has a last-byte-pos value less than its first-byte-pos
first-byte-pos value, or a complete-length value less than or equal value, or a complete-length value less than or equal to its last-
to its last-byte-pos value. The recipient of an invalid byte-pos value. The recipient of an invalid Content-Range MUST NOT
Content-Range MUST NOT attempt to recombine the received content with attempt to recombine the received content with a stored
a stored representation. representation.
A server generating a 416 (Range Not Satisfiable) response to a A server generating a 416 (Range Not Satisfiable) response to a byte-
byte-range request SHOULD send a Content-Range header field with an range request SHOULD send a Content-Range header field with an
unsatisfied-range value, as in the following example: unsatisfied-range value, as in the following example:
Content-Range: bytes */1234 Content-Range: bytes */1234
The complete-length in a 416 response indicates the current length of The complete-length in a 416 response indicates the current length of
the selected representation. the selected representation.
The Content-Range header field has no meaning for status codes that The Content-Range header field has no meaning for status codes that
do not explicitly describe its semantic. For this specification, do not explicitly describe its semantic. For this specification,
only the 206 (Partial Content) and 416 (Range Not Satisfiable) status only the 206 (Partial Content) and 416 (Range Not Satisfiable) status
skipping to change at page 14, line 31 skipping to change at page 13, line 41
Content-Range: bytes 734-1233/1234 Content-Range: bytes 734-1233/1234
4.3. Combining Ranges 4.3. Combining Ranges
A response might transfer only a subrange of a representation if the A response might transfer only a subrange of a representation if the
connection closed prematurely or if the request used one or more connection closed prematurely or if the request used one or more
Range specifications. After several such transfers, a client might Range specifications. After several such transfers, a client might
have received several ranges of the same representation. These have received several ranges of the same representation. These
ranges can only be safely combined if they all have in common the ranges can only be safely combined if they all have in common the
same strong validator (Section 2.1 of [RFC7232]). same strong validator (Section 2.1 of [CONDTNL]).
A client that has received multiple partial responses to GET requests A client that has received multiple partial responses to GET requests
on a target resource MAY combine those responses into a larger on a target resource MAY combine those responses into a larger
continuous range if they share the same strong validator. continuous range if they share the same strong validator.
If the most recent response is an incomplete 200 (OK) response, then If the most recent response is an incomplete 200 (OK) response, then
the header fields of that response are used for any combined response the header fields of that response are used for any combined response
and replace those of the matching stored responses. and replace those of the matching stored responses.
If the most recent response is a 206 (Partial Content) response and If the most recent response is a 206 (Partial Content) response and
skipping to change at page 16, line 31 skipping to change at page 15, line 35
o Pointer to specification text o Pointer to specification text
Values to be added to this namespace require IETF Review (see Values to be added to this namespace require IETF Review (see
[RFC5226], Section 4.1). [RFC5226], Section 4.1).
5.1.2. Registrations 5.1.2. Registrations
The initial range unit registry contains the registrations below: The initial range unit registry contains the registrations below:
+-------------+---------------------------------------+-------------+ +-------------+-----------------------------------------+-----------+
| Range Unit | Description | Reference | | Range Unit | Description | Reference |
| Name | | | | Name | | |
+-------------+---------------------------------------+-------------+ +-------------+-----------------------------------------+-----------+
| bytes | a range of octets | Section 2.1 | | bytes | a range of octets | Section 2 |
| none | reserved as keyword, indicating no | Section 2.3 | | | | .1 |
| | ranges are supported | | | none | reserved as keyword, indicating no | Section 2 |
+-------------+---------------------------------------+-------------+ | | ranges are supported | .3 |
+-------------+-----------------------------------------+-----------+
The change controller is: "IETF (iesg@ietf.org) - Internet The change controller is: "IETF (iesg@ietf.org) - Internet
Engineering Task Force". Engineering Task Force".
5.2. Status Code Registration 5.2. Status Code Registration
The "Hypertext Transfer Protocol (HTTP) Status Code Registry" located The "Hypertext Transfer Protocol (HTTP) Status Code Registry" located
at <http://www.iana.org/assignments/http-status-codes> has been at <http://www.iana.org/assignments/http-status-codes> has been
updated to include the registrations below: updated to include the registrations below:
+-------+-----------------------+-------------+ +-------+-----------------------+--------------+
| Value | Description | Reference | | Value | Description | Reference |
+-------+-----------------------+-------------+ +-------+-----------------------+--------------+
| 206 | Partial Content | Section 4.1 | | 206 | Partial Content | Section 4.1 |
| 416 | Range Not Satisfiable | Section 4.4 | | 416 | Range Not Satisfiable | Section 4.4 |
+-------+-----------------------+-------------+ +-------+-----------------------+--------------+
5.3. Header Field Registration 5.3. Header Field Registration
HTTP header fields are registered within the "Message Headers" HTTP header fields are registered within the "Message Headers"
registry maintained at registry maintained at <http://www.iana.org/assignments/message-
<http://www.iana.org/assignments/message-headers/>. headers/>.
This document defines the following HTTP header fields, so their This document defines the following HTTP header fields, so their
associated registry entries have been updated according to the associated registry entries have been updated according to the
permanent registrations below (see [BCP90]): permanent registrations below (see [BCP90]):
+-------------------+----------+----------+-------------+ +-------------------+----------+----------+--------------+
| Header Field Name | Protocol | Status | Reference | | Header Field Name | Protocol | Status | Reference |
+-------------------+----------+----------+-------------+ +-------------------+----------+----------+--------------+
| Accept-Ranges | http | standard | Section 2.3 | | Accept-Ranges | http | standard | Section 2.3 |
| Content-Range | http | standard | Section 4.2 | | Content-Range | http | standard | Section 4.2 |
| If-Range | http | standard | Section 3.2 | | If-Range | http | standard | Section 3.2 |
| Range | http | standard | Section 3.1 | | Range | http | standard | Section 3.1 |
+-------------------+----------+----------+-------------+ +-------------------+----------+----------+--------------+
The change controller is: "IETF (iesg@ietf.org) - Internet The change controller is: "IETF (iesg@ietf.org) - Internet
Engineering Task Force". Engineering Task Force".
5.4. Internet Media Type Registration 5.4. Internet Media Type Registration
IANA maintains the registry of Internet media types [BCP13] at IANA maintains the registry of Internet media types [BCP13] at
<http://www.iana.org/assignments/media-types>. <http://www.iana.org/assignments/media-types>.
This document serves as the specification for the Internet media type This document serves as the specification for the Internet media type
skipping to change at page 18, line 39 skipping to change at page 17, line 32
Additional information: Additional information:
Deprecated alias names for this type: N/A Deprecated alias names for this type: N/A
Magic number(s): N/A Magic number(s): N/A
File extension(s): N/A File extension(s): N/A
Macintosh file type code(s): N/A Macintosh file type code(s): N/A
Person and email address to contact for further information: See Person and email address to contact for further information: See Aut
Authors' Addresses section. hors' Addresses section.
Intended usage: COMMON Intended usage: COMMON
Restrictions on usage: N/A Restrictions on usage: N/A
Author: See Authors' Addresses section. Author: See Authors' Addresses section.
Change controller: IESG Change controller: IESG
6. Security Considerations 6. Security Considerations
This section is meant to inform developers, information providers, This section is meant to inform developers, information providers,
and users of known security concerns specific to the HTTP range and users of known security concerns specific to the HTTP range
request mechanisms. More general security considerations are request mechanisms. More general security considerations are
addressed in HTTP messaging [RFC7230] and semantics [RFC7231]. addressed in HTTP messaging [MESSGNG] and semantics [SEMNTCS].
6.1. Denial-of-Service Attacks Using Range 6.1. Denial-of-Service Attacks Using Range
Unconstrained multiple range requests are susceptible to denial-of- Unconstrained multiple range requests are susceptible to denial-of-
service attacks because the effort required to request many service attacks because the effort required to request many
overlapping ranges of the same data is tiny compared to the time, overlapping ranges of the same data is tiny compared to the time,
memory, and bandwidth consumed by attempting to serve the requested memory, and bandwidth consumed by attempting to serve the requested
data in many parts. Servers ought to ignore, coalesce, or reject data in many parts. Servers ought to ignore, coalesce, or reject
egregious range requests, such as requests for more than two egregious range requests, such as requests for more than two
overlapping ranges or for many small ranges in a single set, overlapping ranges or for many small ranges in a single set,
particularly when the ranges are requested out of order for no particularly when the ranges are requested out of order for no
apparent reason. Multipart range requests are not designed to apparent reason. Multipart range requests are not designed to
support random access. support random access.
7. Acknowledgments 7. References
See Section 10 of [RFC7230]. 7.1. Normative References
8. References [CACHING] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP): Caching", draft-
ietf-httpbis-cache-00 (work in progress), April 2018.
8.1. Normative References [CONDTNL] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP): Conditional
Requests", draft-ietf-httpbis-conditional-00 (work in
progress), April 2018.
[MESSGNG] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Message
Syntax and Routing", draft-ietf-httpbis-messaging-00 (work
in progress), April 2018.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046, Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996. DOI 10.17487/RFC2046, November 1996,
<https://www.rfc-editor.org/info/rfc2046>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008. Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer <https://www.rfc-editor.org/info/rfc5234>.
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, June 2014.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
June 2014.
[RFC7232] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Conditional Requests", RFC 7232,
June 2014.
[RFC7234] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, [SEMNTCS] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching", Ed., "Hypertext Transfer Protocol (HTTP): Semantics and
RFC 7234, June 2014. Content", draft-ietf-httpbis-semantics-00 (work in
progress), April 2018.
8.2. Informative References 7.2. Informative References
[BCP13] Freed, N., Klensin, J., and T. Hansen, "Media Type [BCP13] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13, Specifications and Registration Procedures", BCP 13,
RFC 6838, January 2013. RFC 6838, January 2013,
<https://www.rfc-editor.org/info/bcp13>.
[BCP90] Klyne, G., Nottingham, M., and J. Mogul, "Registration [BCP90] Klyne, G., Nottingham, M., and J. Mogul, "Registration
Procedures for Message Header Fields", BCP 90, RFC 3864, Procedures for Message Header Fields", BCP 90, RFC 3864,
September 2004. September 2004, <https://www.rfc-editor.org/info/bcp90>.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC7233] Fielding, R., Ed., Lafon, Y., Ed., and J. Reschke, Ed.,
"Hypertext Transfer Protocol (HTTP): Range Requests",
RFC 7233, DOI 10.17487/RFC7233, June 2014,
<https://www.rfc-editor.org/info/rfc7233>.
Appendix A. Internet Media Type multipart/byteranges Appendix A. Internet Media Type multipart/byteranges
When a 206 (Partial Content) response message includes the content of When a 206 (Partial Content) response message includes the content of
multiple ranges, they are transmitted as body parts in a multipart multiple ranges, they are transmitted as body parts in a multipart
message body ([RFC2046], Section 5.1) with the media type of message body ([RFC2046], Section 5.1) with the media type of
"multipart/byteranges". "multipart/byteranges".
The multipart/byteranges media type includes one or more body parts, The multipart/byteranges media type includes one or more body parts,
each with its own Content-Type and Content-Range fields. The each with its own Content-Type and Content-Range fields. The
skipping to change at page 22, line 5 skipping to change at page 21, line 5
Content-Range: exampleunit 1.2-4.3/25 Content-Range: exampleunit 1.2-4.3/25
...the first range... ...the first range...
--THIS_STRING_SEPARATES --THIS_STRING_SEPARATES
Content-Type: video/example Content-Type: video/example
Content-Range: exampleunit 11.2-14.3/25 Content-Range: exampleunit 11.2-14.3/25
...the second range ...the second range
--THIS_STRING_SEPARATES-- --THIS_STRING_SEPARATES--
Appendix B. Changes from RFC 2616 Appendix B. Changes from RFC 7233
Servers are given more leeway in how they respond to a range request,
in order to mitigate abuse by malicious (or just greedy) clients.
(Section 3.1)
A weak validator cannot be used in a 206 response. (Section 4.1)
The Content-Range header field only has meaning when the status code
explicitly defines its use. (Section 4.2)
This specification introduces a Range Unit Registry. (Section 5.1)
multipart/byteranges can consist of a single part. (Appendix A) None yet.
Appendix C. Imported ABNF Appendix C. Imported ABNF
The following core rules are included by reference, as defined in The following core rules are included by reference, as defined in
Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return), Appendix B.1 of [RFC5234]: ALPHA (letters), CR (carriage return),
CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double 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 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 8-bit sequence of data), SP (space), and VCHAR (any visible US-ASCII
character). character).
Note that all rules derived from token are to be compared Note that all rules derived from token are to be compared case-
case-insensitively, like range-unit and acceptable-ranges. insensitively, like range-unit and acceptable-ranges.
The rules below are defined in [RFC7230]: The rules below are defined in [MESSGNG]:
OWS = <OWS, see [RFC7230], Section 3.2.3> OWS = <OWS, see [MESSGNG], Section 3.2.3>
token = <token, see [RFC7230], Section 3.2.6> token = <token, see [MESSGNG], Section 3.2.6>
The rules below are defined in other parts: The rules below are defined in other parts:
HTTP-date = <HTTP-date, see [RFC7231], Section 7.1.1.1> HTTP-date = <HTTP-date, see [SEMNTCS], Section 7.1.1.1>
entity-tag = <entity-tag, see [RFC7232], Section 2.3> entity-tag = <entity-tag, see [CONDTNL], Section 2.3>
Appendix D. Collected ABNF Appendix D. Collected ABNF
In the collected ABNF below, list rules are expanded as per Section In the collected ABNF below, list rules are expanded as per
1.2 of [RFC7230]. Section 1.2 of [MESSGNG].
Accept-Ranges = acceptable-ranges Accept-Ranges = acceptable-ranges
Content-Range = byte-content-range / other-content-range Content-Range = byte-content-range / other-content-range
HTTP-date = <HTTP-date, see [RFC7231], Section 7.1.1.1> HTTP-date = <HTTP-date, see [SEMNTCS], Section 7.1.1.1>
If-Range = entity-tag / HTTP-date If-Range = entity-tag / HTTP-date
OWS = <OWS, see [RFC7230], Section 3.2.3> OWS = <OWS, see [MESSGNG], Section 3.2.3>
Range = byte-ranges-specifier / other-ranges-specifier Range = byte-ranges-specifier / other-ranges-specifier
acceptable-ranges = ( *( "," OWS ) range-unit *( OWS "," [ OWS acceptable-ranges = ( *( "," OWS ) range-unit *( OWS "," [ OWS
range-unit ] ) ) / "none" range-unit ] ) ) / "none"
byte-content-range = bytes-unit SP ( byte-range-resp / byte-content-range = bytes-unit SP ( byte-range-resp /
unsatisfied-range ) unsatisfied-range )
byte-range = first-byte-pos "-" last-byte-pos byte-range = first-byte-pos "-" last-byte-pos
byte-range-resp = byte-range "/" ( complete-length / "*" ) byte-range-resp = byte-range "/" ( complete-length / "*" )
byte-range-set = *( "," OWS ) ( byte-range-spec / byte-range-set = *( "," OWS ) ( byte-range-spec /
suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec / suffix-byte-range-spec ) *( OWS "," [ OWS ( byte-range-spec /
suffix-byte-range-spec ) ] ) suffix-byte-range-spec ) ] )
byte-range-spec = first-byte-pos "-" [ last-byte-pos ] byte-range-spec = first-byte-pos "-" [ last-byte-pos ]
byte-ranges-specifier = bytes-unit "=" byte-range-set byte-ranges-specifier = bytes-unit "=" byte-range-set
bytes-unit = "bytes" bytes-unit = "bytes"
complete-length = 1*DIGIT complete-length = 1*DIGIT
entity-tag = <entity-tag, see [RFC7232], Section 2.3> entity-tag = <entity-tag, see [CONDTNL], Section 2.3>
first-byte-pos = 1*DIGIT first-byte-pos = 1*DIGIT
last-byte-pos = 1*DIGIT last-byte-pos = 1*DIGIT
other-content-range = other-range-unit SP other-range-resp other-content-range = other-range-unit SP other-range-resp
other-range-resp = *CHAR other-range-resp = *CHAR
other-range-set = 1*VCHAR other-range-set = 1*VCHAR
other-range-unit = token other-range-unit = token
other-ranges-specifier = other-range-unit "=" other-range-set other-ranges-specifier = other-range-unit "=" other-range-set
range-unit = bytes-unit / other-range-unit range-unit = bytes-unit / other-range-unit
suffix-byte-range-spec = "-" suffix-length suffix-byte-range-spec = "-" suffix-length
suffix-length = 1*DIGIT suffix-length = 1*DIGIT
token = <token, see [RFC7230], Section 3.2.6> token = <token, see [MESSGNG], Section 3.2.6>
unsatisfied-range = "*/" complete-length unsatisfied-range = "*/" complete-length
Appendix E. Change Log
This section is to be removed before publishing as an RFC.
E.1. Since RFC 7233
The changes in this draft are purely editorial:
o Change boilerplate and abstract to indicate the "draft" status,
and update references to ancestor specifications.
o Remove version "1.1" from document title, indicating that this
specification applies to all HTTP versions.
o Adjust historical notes.
o Update links to sibling specifications.
o Replace sections listing changes from RFC 2616 by new empty
sections referring to RFC 723x.
o Remove acknowledgements specific to RFC 723x.
o Move "Acknowledgements" to the very end and make them unnumbered.
Index Index
2 2
206 Partial Content (status code) 10 206 Partial Content (status code) 9
4 4
416 Range Not Satisfiable (status code) 15 416 Range Not Satisfiable (status code) 14
A A
Accept-Ranges header field 7 Accept-Ranges header field 6
C C
Content-Range header field 12 Content-Range header field 11
G G
Grammar Grammar
Accept-Ranges 7 Accept-Ranges 6
acceptable-ranges 7 acceptable-ranges 6
byte-content-range 12 byte-content-range 12
byte-range 12 byte-range 12
byte-range-resp 12 byte-range-resp 12
byte-range-set 5 byte-range-set 5
byte-range-spec 5 byte-range-spec 5
byte-ranges-specifier 5 byte-ranges-specifier 5
bytes-unit 5 bytes-unit 4
complete-length 12 complete-length 12
Content-Range 12 Content-Range 12
first-byte-pos 5 first-byte-pos 5
If-Range 9 If-Range 8
last-byte-pos 5 last-byte-pos 5
other-content-range 12 other-content-range 12
other-range-resp 12 other-range-resp 12
other-range-unit 5, 7 other-range-unit 4, 6
Range 8 Range 7
range-unit 5 range-unit 4
ranges-specifier 5 ranges-specifier 5
suffix-byte-range-spec 6 suffix-byte-range-spec 5
suffix-length 6 suffix-length 5
unsatisfied-range 12 unsatisfied-range 12
I I
If-Range header field 9 If-Range header field 8
M M
Media Type Media Type
multipart/byteranges 18, 21 multipart/byteranges 16, 20
multipart/x-byteranges 19 multipart/x-byteranges 20
multipart/byteranges Media Type 18, 21 multipart/byteranges Media Type 16, 20
multipart/x-byteranges Media Type 21 multipart/x-byteranges Media Type 20
R R
Range header field 8 Range header field 7
Acknowledgments
See Appendix "Acknowledgments" of [MESSGNG].
Authors' Addresses Authors' Addresses
Roy T. Fielding (editor) Roy T. Fielding (editor)
Adobe Systems Incorporated Adobe
345 Park Ave 345 Park Ave
San Jose, CA 95110 San Jose, CA 95110
USA USA
EMail: fielding@gbiv.com EMail: fielding@gbiv.com
URI: http://roy.gbiv.com/ URI: http://roy.gbiv.com/
Mark Nottingham (editor)
Fastly
Yves Lafon (editor) EMail: mnot@mnot.net
World Wide Web Consortium URI: https://www.mnot.net/
W3C / ERCIM
2004, rte des Lucioles
Sophia-Antipolis, AM 06902
France
EMail: ylafon@w3.org
URI: http://www.raubacapeu.net/people/yves/
Julian F. Reschke (editor) Julian F. Reschke (editor)
greenbytes GmbH greenbytes GmbH
Hafenweg 16 Hafenweg 16
Muenster, NW 48155 Muenster, NW 48155
Germany Germany
EMail: julian.reschke@greenbytes.de EMail: julian.reschke@greenbytes.de
URI: http://greenbytes.de/tech/webdav/ URI: http://greenbytes.de/tech/webdav/
 End of changes. 74 change blocks. 
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