draft-ietf-httpbis-p5-range-22.txt   rfc7233.txt 
HTTPbis Working Group R. Fielding, Ed. Internet Engineering Task Force (IETF) R. Fielding, Ed.
Internet-Draft Adobe Request for Comments: 7233 Adobe
Obsoletes: 2616 (if approved) Y. Lafon, Ed. Obsoletes: 2616 Y. Lafon, Ed.
Intended status: Standards Track W3C Category: Standards Track W3C
Expires: August 27, 2013 J. Reschke, Ed. ISSN: 2070-1721 J. Reschke, Ed.
greenbytes greenbytes
February 23, 2013 June 2014
Hypertext Transfer Protocol (HTTP/1.1): Range Requests Hypertext Transfer Protocol (HTTP/1.1): Range Requests
draft-ietf-httpbis-p5-range-22
Abstract Abstract
The Hypertext Transfer Protocol (HTTP) is an application-level The Hypertext Transfer Protocol (HTTP) is a stateless application-
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.
Editorial Note (To be removed by RFC Editor)
Discussion of this draft takes place on the HTTPBIS working group
mailing list (ietf-http-wg@w3.org), which is archived at
<http://lists.w3.org/Archives/Public/ietf-http-wg/>.
The current issues list is at
<http://tools.ietf.org/wg/httpbis/trac/report/3> and related
documents (including fancy diffs) can be found at
<http://tools.ietf.org/wg/httpbis/>.
The changes in this draft are summarized in Appendix E.3.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on August 27, 2013. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7233.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 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
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
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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
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 3, line 7 skipping to change at page 3, line 7
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 ....................................................4
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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Range Units .....................................................5
2.1. Byte Ranges . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Byte Ranges ................................................5
2.2. Other Range Units . . . . . . . . . . . . . . . . . . . . 7 2.2. Other Range Units ..........................................7
2.3. Accept-Ranges . . . . . . . . . . . . . . . . . . . . . . 7 2.3. Accept-Ranges ..............................................7
3. Range Requests . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Range Requests ..................................................8
3.1. Range . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1. Range ......................................................8
3.2. If-Range . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2. If-Range ...................................................9
4. Responses to a Range Request . . . . . . . . . . . . . . . . . 9 4. Responses to a Range Request ...................................10
4.1. 206 Partial Content . . . . . . . . . . . . . . . . . . . 10 4.1. 206 Partial Content .......................................10
4.2. Content-Range . . . . . . . . . . . . . . . . . . . . . . 12 4.2. Content-Range .............................................12
4.3. Combining Ranges . . . . . . . . . . . . . . . . . . . . . 14 4.3. Combining Ranges ..........................................14
4.4. 416 Range Not Satisfiable . . . . . . . . . . . . . . . . 15 4.4. 416 Range Not Satisfiable .................................15
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 5. IANA Considerations ............................................16
5.1. Range Unit Registry . . . . . . . . . . . . . . . . . . . 15 5.1. Range Unit Registry .......................................16
5.1.1. Procedure . . . . . . . . . . . . . . . . . . . . . . 15 5.1.1. Procedure ..........................................16
5.1.2. Registrations . . . . . . . . . . . . . . . . . . . . 16 5.1.2. Registrations ......................................16
5.2. Status Code Registration . . . . . . . . . . . . . . . . . 16 5.2. Status Code Registration ..................................17
5.3. Header Field Registration . . . . . . . . . . . . . . . . 16 5.3. Header Field Registration .................................17
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17 5.4. Internet Media Type Registration ..........................17
6.1. Denial of Service Attacks using Range . . . . . . . . . . 17 5.4.1. Internet Media Type multipart/byteranges ...........18
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 6. Security Considerations ........................................19
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6.1. Denial-of-Service Attacks Using Range .....................19
8.1. Normative References . . . . . . . . . . . . . . . . . . . 17 7. Acknowledgments ................................................19
8.2. Informative References . . . . . . . . . . . . . . . . . . 18 8. References .....................................................20
Appendix A. Internet Media Type multipart/byteranges . . . . . . 18 8.1. Normative References ......................................20
Appendix B. Changes from RFC 2616 . . . . . . . . . . . . . . . . 20 8.2. Informative References ....................................20
Appendix C. Imported ABNF . . . . . . . . . . . . . . . . . . . . 21 Appendix A. Internet Media Type multipart/byteranges ..............21
Appendix D. Collected ABNF . . . . . . . . . . . . . . . . . . . 21 Appendix B. Changes from RFC 2616 .................................22
Appendix E. Change Log (to be removed by RFC Editor before Appendix C. Imported ABNF .........................................22
publication) . . . . . . . . . . . . . . . . . . . . 23 Appendix D. Collected ABNF ........................................23
E.1. Since draft-ietf-httpbis-p5-range-19 . . . . . . . . . . . 23 Index .............................................................24
E.2. Since draft-ietf-httpbis-p5-range-20 . . . . . . . . . . . 23
E.3. Since draft-ietf-httpbis-p5-range-21 . . . . . . . . . . . 23
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
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
representation, such as a single page of a very large document, or representation, such as a single page of a very large document, or
the dimensions of an embedded image. the dimensions of an embedded image.
This document defines HTTP/1.1 range requests, partial responses, and This document defines HTTP/1.1 range requests, partial responses, and
the multipart/byteranges media type, obsoleting those parts the multipart/byteranges media type. Range requests are an OPTIONAL
previously defined in [RFC2616]. Range requests are an OPTIONAL
feature of HTTP, designed so that recipients not implementing this feature of HTTP, designed so that recipients not implementing this
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.
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 [Part1]. defined in Section 2.5 of [RFC7230].
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 the list rule extension defined in Section notation of [RFC5234] with a list extension, defined in Section 7 of
1.2 of [Part1]. Appendix C describes rules imported from other [RFC7230], that allows for compact definition of comma-separated
documents. Appendix D shows the collected ABNF with the list rule lists using a '#' operator (similar to how the '*' operator indicates
expanded. repetition). Appendix C describes rules imported from other
documents. Appendix D shows the collected grammar with all list
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
Accept-Ranges (Section 2.3) response header field to advertise Accept-Ranges (Section 2.3) response header field to advertise
support for range requests, the Range (Section 3.1) request header support for range requests, the Range (Section 3.1) request header
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 [Part2]). We representation transferable over HTTP (Section 3 of [RFC7231]). The
define the "bytes" range unit 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 operation MAY specify a single range of bytes, or a set A byte-range request can specify a single range of bytes or a set of
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 )
byte-range-spec = first-byte-pos "-" [ last-byte-pos ] byte-range-spec = first-byte-pos "-" [ last-byte-pos ]
first-byte-pos = 1*DIGIT first-byte-pos = 1*DIGIT
last-byte-pos = 1*DIGIT last-byte-pos = 1*DIGIT
The first-byte-pos value in a byte-range-spec gives the byte-offset The first-byte-pos value in a byte-range-spec gives the byte-offset
of the first byte in a range. The last-byte-pos value gives the of the first byte in a range. The last-byte-pos value gives the
byte-offset of the last byte in the range; that is, the byte byte-offset of the last byte in the range; that is, the byte
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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 suffix- If the selected representation is shorter than the specified
length, the entire representation is used. For example (assuming a suffix-length, the entire representation is used.
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 non- representation, or at least one suffix-byte-range-spec with a
zero suffix-length, then the byte-range-set is satisfiable. non-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 suffix- In the byte-range syntax, first-byte-pos, last-byte-pos, and
length are expressed as decimal number of octets. Since there is no suffix-length are expressed as decimal number of octets. Since there
predefined limit to the length of a payload, recipients ought to is no 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
2.3. Accept-Ranges 2.3. Accept-Ranges
The "Accept-Ranges" header field allows a server to indicate that it The "Accept-Ranges" header field allows a server to indicate that it
supports range requests for the target resource. supports range requests for the target resource.
Accept-Ranges = acceptable-ranges Accept-Ranges = acceptable-ranges
acceptable-ranges = 1#range-unit / "none" acceptable-ranges = 1#range-unit / "none"
Origin servers that support byte-range requests MAY send An origin server that supports byte-range requests for a given target
resource MAY send
Accept-Ranges: bytes Accept-Ranges: bytes
but are not required to do so. Clients MAY generate range requests to indicate what range units are supported. A client MAY generate
without having received this header field for the resource involved. range requests without having received this header field for the
Range units are defined in Section 2. resource involved. Range units are defined in Section 2.
Servers that do not support any kind of range request for the target A server that does not support any kind of range request for the
resource resource MAY send target resource MAY send
Accept-Ranges: none Accept-Ranges: none
to advise the client not to attempt a range request. to advise the client not to attempt a range request.
3. Range Requests 3. Range Requests
3.1. Range 3.1. Range
The "Range" header field on a GET request modifies the method The "Range" header field on a GET request modifies the method
semantics to request transfer of only one or more subranges of the semantics to request transfer of only one or more subranges of the
selected representation data, rather than the entire selected selected representation data, rather than the entire selected
representation data. representation data.
Range = byte-ranges-specifier / other-ranges-specifier Range = byte-ranges-specifier / other-ranges-specifier
other-ranges-specifier = other-range-unit "=" other-range-set other-ranges-specifier = other-range-unit "=" other-range-set
other-range-set = 1*CHAR other-range-set = 1*VCHAR
A server MAY ignore the Range header field. However, origin servers A server MAY ignore the Range header field. However, origin servers
and intermediate caches ought to support byte ranges when possible, and intermediate caches ought to support byte ranges when possible,
since Range supports efficient recovery from partially failed since Range supports efficient recovery from partially failed
transfers and partial retrieval of large representations. A server transfers and partial retrieval of large representations. A server
MUST ignore a Range header field received with a request method other MUST ignore a Range header field received with a request method other
than GET. than GET.
An origin server MUST ignore a Range header field that contains a An origin server MUST ignore a Range header field that contains a
range unit it does not understand. A proxy MAY either discard a range unit it does not understand. A proxy MAY discard a Range
Range header field that contains a range unit it does not understand header field that contains a range unit it does not understand.
or pass it to the next inbound server when forwarding the request.
A server that supports range requests ought to ignore or reject a A server that supports range requests MAY ignore or reject a Range
Range header field that consists of more than two overlapping ranges, header field that consists of more than two overlapping ranges, or a
or a set of many small ranges that are not listed in ascending order, set of many small ranges that are not listed in ascending order,
since both are indications of either a broken client or a deliberate since both are indications of either a broken client or a deliberate
denial of service attack (Section 6.1). A client SHOULD NOT request denial-of-service attack (Section 6.1). A client SHOULD NOT request
multiple ranges that are inherently less efficient to process and multiple ranges that are inherently less efficient to process and
transfer than a single range that encompasses the same data. transfer than a single range that encompasses the same data.
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 The Range header field is evaluated after evaluating the precondition
preconditions of [Part4] and only if the result of their evaluation header fields defined in [RFC7232], and only if the result in absence
is leading toward a 200 (OK) response. In other words, Range is of the Range header field would be a 200 (OK) response. In other
ignored when a conditional GET would result in a 304 (Not Modified) words, Range is ignored when a conditional GET would result in a 304
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
send a 206 (Partial Content) response with a payload containing one send a 206 (Partial Content) response with a payload containing one
or more partial representations that correspond to the satisfiable or more partial representations that correspond to the satisfiable
ranges requested, as defined in Section 4. ranges requested, as defined in Section 4.
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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
invalid or unsatisfiable, the server SHOULD send a 416 (Range Not invalid or unsatisfiable, the server SHOULD send a 416 (Range Not
Satisfiable) response. Satisfiable) response.
3.2. If-Range 3.2. If-Range
If a client has a partial copy of a representation and wishes to have 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 an up-to-date copy of the entire representation, it could use the
Range header field with a conditional GET (using either or both of Range header field with a conditional GET (using either or both of
If-Unmodified-Since and If-Match.) However, if the condition fails If-Unmodified-Since and If-Match.) However, if the precondition
because the representation has been modified, the client would then fails because the representation has been modified, the client would
have to make a second request to obtain the entire current then have to make a second request to obtain the entire current
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: if the representation is second request. Informally, its meaning is as follows: if the
unchanged, send me the part(s) that I am requesting in Range; representation is unchanged, send me the part(s) that I am requesting
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
Clients MUST NOT use an entity-tag marked as weak in an If-Range
field value and MUST NOT use a Last-Modified date in an If-Range
field value unless it has no entity-tag for the representation and
the Last-Modified date it does have for the representation is strong
in the sense defined by Section 2.2.2 of [Part4].
A server that evaluates a conditional range request that is
applicable to one of its representations MUST evaluate the condition
as false if the entity-tag used as a validator is marked as weak or,
when an HTTP-date is used as the validator, if the date value is not
strong in the sense defined by Section 2.2.2 of [Part4]. (A server
can distinguish between a valid HTTP-date and any form of entity-tag
by examining the first two characters.)
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 If- does not contain a Range header field. A server MUST ignore an
Range header field received in a request that does not contain a If-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
entity-tag that is marked as weak. A client MUST NOT generate an
If-Range header field containing an HTTP-date 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 [RFC7232].
A server that evaluates an If-Range precondition MUST use the strong
comparison function when comparing entity-tags (Section 2.3.2 of
[RFC7232]) and MUST evaluate the condition as false if an HTTP-date
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
distinguished from a valid HTTP-date by examining the first two
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, then the server MUST requested. If the validator does not match, the server MUST ignore
ignore the Range header field. the Range header field. Note that this comparison by exact match,
including when the validator is an HTTP-date, differs from the
"earlier than or equal to" comparison used when evaluating an
If-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 requests's Range correspond to the satisfiable ranges found in the request's Range
header field (Section 3.1). header field (Section 3.1).
If a single part is being transferred, the server generating the 206 If a single part is being transferred, the server generating the 206
response MUST generate a Content-Range header field, describing what response MUST generate a Content-Range header field, describing what
range of the selected representation is enclosed, and a payload range of the selected representation is enclosed, and a payload
consisting of the range. For example: consisting of the range. For example:
HTTP/1.1 206 Partial Content HTTP/1.1 206 Partial Content
Date: Wed, 15 Nov 1995 06:25:24 GMT Date: Wed, 15 Nov 1995 06:25:24 GMT
Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT
Content-Range: bytes 21010-47021/47022 Content-Range: bytes 21010-47021/47022
Content-Length: 26012 Content-Length: 26012
Content-Type: image/gif Content-Type: image/gif
... 26012 bytes of partial image data ... ... 26012 bytes of partial image data ...
If multiple parts are being transferred, the server generating the If multiple parts are being transferred, the server generating the
206 response MUST generate a "multipart/byteranges" payload, as 206 response MUST generate a "multipart/byteranges" payload, as
defined in Appendix A, and a Content-Type header field containing the defined in Appendix A, and a Content-Type header field containing the
multipart/byteranges media type and its required boundary parameter. multipart/byteranges media type and its required boundary parameter.
To avoid confusion with single part responses, a server MUST NOT To avoid confusion with single-part responses, a server MUST NOT
generate a Content-Range header field in the HTTP header block of a generate a Content-Range header field in the HTTP header section of a
multiple part response (this field will be sent in each part multiple part response (this field will be sent in each part
instead). instead).
Within the header area of each body part in the multipart payload, Within the header area of each body part in the multipart payload,
the server MUST generate a Content-Range header field corresponding the server MUST generate a Content-Range header field corresponding
to the range being enclosed in that body part. If the selected to the range being enclosed in that body part. If the selected
representation would have had a Content-Type header field in a 200 representation would have had a Content-Type header field in a 200
(OK) response, the server SHOULD generate that same Content-Type (OK) response, the server SHOULD generate that same Content-Type
field in the header area of each body part. For example: field in the header area of each body part. For example:
skipping to change at page 11, line 24 skipping to change at page 11, line 31
...the first range... ...the first range...
--THIS_STRING_SEPARATES --THIS_STRING_SEPARATES
Content-Type: application/pdf Content-Type: application/pdf
Content-Range: bytes 7000-7999/8000 Content-Range: bytes 7000-7999/8000
...the second range ...the second range
--THIS_STRING_SEPARATES-- --THIS_STRING_SEPARATES--
When multiple ranges are requested, a server MAY coalesce any of the 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 ranges that overlap, or that are separated by a gap that is smaller
than the overhead of sending multiple parts, regardless of the order than the overhead of sending multiple parts, regardless of the order
in which the corresponding byte-range-spec appeared in the received in which the corresponding byte-range-spec appeared in the received
Range header field. Since the typical overhead between parts of a Range header field. Since the typical overhead between parts of a
multipart/byteranges payload is around 80 bytes, depending on the multipart/byteranges payload is around 80 bytes, depending on the
selected representation's media type and the chosen boundary selected representation's media type and the chosen boundary
parameter length, it can be less efficient to transfer many small parameter length, it can be less efficient to transfer many small
disjoint parts than it is to transfer the entire selected disjoint parts than it is to transfer the entire selected
representation. representation.
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 ask for that cannot process a multipart/byteranges response MUST NOT generate
multiple ranges in a single request. 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 byte-range- send the parts in the same order that the corresponding
spec appeared in the received Range header field, excluding those byte-range-spec appeared in the received Range header field,
ranges that were deemed unsatisfiable or that were coalesced into excluding those ranges that were deemed unsatisfiable or that were
other ranges. A client that receives a multipart response MUST coalesced into other ranges. A client that receives a multipart
inspect the Content-Range header field present in each body part in response MUST inspect the Content-Range header field present in each
order to determine which range is contained in that body part; a body part in order to determine which range is contained in that body
client cannot rely on receiving the same ranges that it requested, part; a client cannot rely on receiving the same ranges that it
nor the same order that it requested. 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 unless otherwise indicated by explicit A 206 response is cacheable by default; i.e., unless otherwise
cache controls (see Section 4.1.2 of [Part6]). indicated by explicit cache controls (see Section 4.2.2 of
[RFC7234]).
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.
skipping to change at page 13, line 20 skipping to change at page 13, line 28
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 byte-range- A Content-Range field value is invalid if it contains a
resp that has a last-byte-pos value less than its first-byte-pos byte-range-resp that has a last-byte-pos value less than its
value, or a complete-length value less than or equal to its last- first-byte-pos value, or a complete-length value less than or equal
byte-pos value. The recipient of an invalid Content-Range MUST NOT to its last-byte-pos value. The recipient of an invalid
attempt to recombine the received content with a stored Content-Range MUST NOT attempt to recombine the received content with
representation. a stored representation.
A server generating a 416 (Range Not Satisfiable) response to a byte A server generating a 416 (Range Not Satisfiable) response to a
range request SHOULD send a Content-Range header field with an byte-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
codes describe a meaning for Content-Range. codes describe a meaning for Content-Range.
The following are examples of Content-Range values in which the The following are examples of Content-Range values in which the
selected representation contains a total of 1234 bytes: selected representation contains a total of 1234 bytes:
o The first 500 bytes: o The first 500 bytes:
Content-Range: bytes 0-499/1234 Content-Range: bytes 0-499/1234
skipping to change at page 14, line 20 skipping to change at page 14, line 31
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, where "strong validator" is defined to be same strong validator (Section 2.1 of [RFC7232]).
either an entity-tag that is not marked as weak (Section 2.3 of
[Part4]) or, if no entity-tag is provided, a Last-Modified value that
is strong in the sense defined by Section 2.2.2 of [Part4].
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 14, line 47 skipping to change at page 15, line 8
are 206 responses, then the stored response with the most recent are 206 responses, then the stored response with the most recent
header fields is used as the source of header fields for the combined header fields is used as the source of header fields for the combined
response, except that the client MUST use other header fields response, except that the client MUST use other header fields
provided in the new response, aside from Content-Range, to replace provided in the new response, aside from Content-Range, to replace
all instances of the corresponding header fields in the stored all instances of the corresponding header fields in the stored
response. response.
The combined response message body consists of the union of partial The combined response message body consists of the union of partial
content ranges in the new response and each of the selected content ranges in the new response and each of the selected
responses. If the union consists of the entire range of the responses. If the union consists of the entire range of the
representation, then the client MUST record the combined response as representation, then the client MUST process the combined response as
if it were a complete 200 (OK) response, including a Content-Length if it were a complete 200 (OK) response, including a Content-Length
header field that reflects the complete length. Otherwise, the header field that reflects the complete length. Otherwise, the
client MUST record the set of continuous ranges as one of the client MUST process the set of continuous ranges as one of the
following: an incomplete 200 (OK) response if the combined response following: an incomplete 200 (OK) response if the combined response
is a prefix of the representation, a single 206 (Partial Content) is a prefix of the representation, a single 206 (Partial Content)
response containing a multipart/byteranges body, or multiple 206 response containing a multipart/byteranges body, or multiple 206
(Partial Content) responses, each with one continuous range that is (Partial Content) responses, each with one continuous range that is
indicated by a Content-Range header field. indicated by a Content-Range header field.
4.4. 416 Range Not Satisfiable 4.4. 416 Range Not Satisfiable
The 416 (Range Not Satisfiable) status code indicates that none of The 416 (Range Not Satisfiable) status code indicates that none of
the ranges in the request's Range header field (Section 3.1) overlap the ranges in the request's Range header field (Section 3.1) overlap
the current extent of the selected resource or that the set of ranges the current extent of the selected resource or that the set of ranges
requested has been rejected due to invalid ranges or an excessive requested has been rejected due to invalid ranges or an excessive
request of small or overlapping ranges. request of small or overlapping ranges.
For byte ranges, failing to overlap the current extent means that the For byte ranges, failing to overlap the current extent means that the
first-byte-pos of all of the byte-range-spec values were greater than first-byte-pos of all of the byte-range-spec values were greater than
the current length of the selected representation. When this status the current length of the selected representation. When this status
code is generated in response to a byte range request, the sender code is generated in response to a byte-range request, the sender
SHOULD generate a Content-Range header field specifying the current SHOULD generate a Content-Range header field specifying the current
length of the selected representation (Section 4.2). length of the selected representation (Section 4.2).
For example: For example:
HTTP/1.1 416 Range Not Satisfiable HTTP/1.1 416 Range Not Satisfiable
Date: Mon, 20 Jan 2012 15:41:54 GMT Date: Fri, 20 Jan 2012 15:41:54 GMT
Content-Range: bytes */47022 Content-Range: bytes */47022
Note: Because servers are free to ignore Range, many Note: Because servers are free to ignore Range, many
implementations will simply respond with 200 (OK) if the requested implementations will simply respond with the entire selected
ranges are invalid or not satisfiable. That is partly because representation in a 200 (OK) response. That is partly because
most clients are prepared to receive a 200 (OK) to complete the most clients are prepared to receive a 200 (OK) to complete the
task (albeit less efficiently) and partly because clients might task (albeit less efficiently) and partly because clients might
not stop making an invalid partial request until they have not stop making an invalid partial request until they have
received a complete representation. Thus, clients cannot depend received a complete representation. Thus, clients cannot depend
on receiving a 416 (Range Not Satisfiable) response even when it on receiving a 416 (Range Not Satisfiable) response even when it
is most appropriate. is most appropriate.
5. IANA Considerations 5. IANA Considerations
5.1. Range Unit Registry 5.1. Range Unit Registry
The HTTP Range Unit Registry defines the name space for the range The "HTTP Range Unit Registry" defines the namespace for the range
unit names and refers to their corresponding specifications. The unit names and refers to their corresponding specifications. The
registry is maintained at registry has been created and is now maintained at
<http://www.iana.org/assignments/http-parameters>. <http://www.iana.org/assignments/http-parameters>.
5.1.1. Procedure 5.1.1. Procedure
Registration of an HTTP Range Unit MUST include the following fields: Registration of an HTTP Range Unit MUST include the following fields:
o Name o Name
o Description o Description
o Pointer to specification text o Pointer to specification text
Values to be added to this name space 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 HTTP Range Unit Registry shall contain the registrations The initial range unit registry contains the registrations below:
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 2.1 |
| none | reserved as keyword, indicating no | Section 2.3 | | none | reserved as keyword, indicating no | Section 2.3 |
| | ranges are supported | | | | ranges are supported | |
+-------------+---------------------------------------+-------------+ +-------------+---------------------------------------+-------------+
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 HTTP Status Code Registry located at The "Hypertext Transfer Protocol (HTTP) Status Code Registry" located
<http://www.iana.org/assignments/http-status-codes> shall be updated at <http://www.iana.org/assignments/http-status-codes> has been
with 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
The Message Header Field Registry located at <http://www.iana.org/ HTTP header fields are registered within the "Message Headers"
assignments/message-headers/message-header-index.html> shall be registry maintained at
updated with the permanent registrations below (see [BCP90]): <http://www.iana.org/assignments/message-headers/>.
This document defines the following HTTP header fields, so their
associated registry entries have been updated according to the
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
IANA maintains the registry of Internet media types [BCP13] at
<http://www.iana.org/assignments/media-types>.
This document serves as the specification for the Internet media type
"multipart/byteranges". The following has been registered with IANA.
5.4.1. Internet Media Type multipart/byteranges
Type name: multipart
Subtype name: byteranges
Required parameters: boundary
Optional parameters: N/A
Encoding considerations: only "7bit", "8bit", or "binary" are
permitted
Security considerations: see Section 6
Interoperability considerations: N/A
Published specification: This specification (see Appendix A).
Applications that use this media type: HTTP components supporting
multiple ranges in a single request.
Fragment identifier considerations: N/A
Additional information:
Deprecated alias names for this type: N/A
Magic number(s): N/A
File extension(s): N/A
Macintosh file type code(s): N/A
Person and email address to contact for further information: See
Authors' Addresses section.
Intended usage: COMMON
Restrictions on usage: N/A
Author: See Authors' Addresses section.
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/1.1 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 [Part1] and semantics [Part2]. addressed in HTTP messaging [RFC7230] and semantics [RFC7231].
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. Acknowledgments
See Section 9 of [Part1]. See Section 10 of [RFC7230].
8. References 8. References
8.1. Normative References 8.1. Normative References
[Part1] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
draft-ietf-httpbis-p1-messaging-22 (work in progress),
February 2013.
[Part2] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content",
draft-ietf-httpbis-p2-semantics-22 (work in progress),
February 2013.
[Part4] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Conditional Requests",
draft-ietf-httpbis-p4-conditional-22 (work in progress),
February 2013.
[Part6] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
draft-ietf-httpbis-p6-cache-22 (work in progress),
February 2013.
[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. November 1996.
[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, March 1997.
[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, January 2008.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
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,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
RFC 7234, June 2014.
8.2. Informative References 8.2. 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.
[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.
skipping to change at page 18, line 49 skipping to change at page 21, line 10
[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. May 2008.
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". The following definition is to be registered "multipart/byteranges".
with IANA [BCP13].
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
required boundary parameter specifies the boundary string used to required boundary parameter specifies the boundary string used to
separate each body part. separate each body part.
Type name: multipart
Subtype name: byteranges
Required parameters: boundary
Optional parameters: none
Encoding considerations: only "7bit", "8bit", or "binary" are
permitted
Security considerations: none
Interoperability considerations: none
Published specification: This specification (see Appendix A).
Applications that use this media type: HTTP components supporting
multiple ranges in a single request.
Additional information:
Magic number(s): none
File extension(s): none
Macintosh file type code(s): none
Person and email address to contact for further information: See
Authors Section.
Intended usage: COMMON
Restrictions on usage: none
Author/Change controller: IESG
Implementation Notes: Implementation Notes:
1. Additional CRLFs might precede the first boundary string in the 1. Additional CRLFs might precede the first boundary string in the
body. body.
2. Although [RFC2046] permits the boundary string to be quoted, some 2. Although [RFC2046] permits the boundary string to be quoted, some
existing implementations handle a quoted boundary string existing implementations handle a quoted boundary string
incorrectly. incorrectly.
3. A number of clients and servers were coded to an early draft of 3. A number of clients and servers were coded to an early draft of
skipping to change at page 20, line 38 skipping to change at page 22, line 7
...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 2616
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) 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 The Content-Range header field only has meaning when the status code
explicitly defines its use. (Section 4.2) explicitly defines its use. (Section 4.2)
Servers are given more leeway in how they respond to a range request, This specification introduces a Range Unit Registry. (Section 5.1)
in order to mitigate abuse by malicious (or just greedy) clients.
multipart/byteranges can consist of a single part. (Appendix A) multipart/byteranges can consist of a single part. (Appendix A)
This specification introduces a Range Unit Registry. (Section 5.1)
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 case- Note that all rules derived from token are to be compared
insensitively, like range-unit and acceptable-ranges. case-insensitively, like range-unit and acceptable-ranges.
The rules below are defined in [Part1]: The rules below are defined in [RFC7230]:
OWS = <OWS, defined in [Part1], Section 3.2.3> OWS = <OWS, see [RFC7230], Section 3.2.3>
token = <token, defined in [Part1], Section 3.2.6> token = <token, see [RFC7230], Section 3.2.6>
The rules below are defined in other parts: The rules below are defined in other parts:
HTTP-date = <HTTP-date, defined in [Part2], Section 7.1.1.1> HTTP-date = <HTTP-date, see [RFC7231], Section 7.1.1.1>
entity-tag = <entity-tag, defined in [Part4], Section 2.3> entity-tag = <entity-tag, see [RFC7232], Section 2.3>
Appendix D. Collected ABNF Appendix D. Collected ABNF
In the collected ABNF below, list rules are expanded as per Section
1.2 of [RFC7230].
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, defined in [Part2], Section 7.1.1.1> HTTP-date = <HTTP-date, see [RFC7231], Section 7.1.1.1>
If-Range = entity-tag / HTTP-date If-Range = entity-tag / HTTP-date
OWS = <OWS, defined in [Part1], Section 3.2.3> OWS = <OWS, see [RFC7230], 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, defined in [Part4], Section 2.3> entity-tag = <entity-tag, see [RFC7232], 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*CHAR 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, defined in [Part1], Section 3.2.6> token = <token, see [RFC7230], Section 3.2.6>
unsatisfied-range = "*/" complete-length unsatisfied-range = "*/" complete-length
Appendix E. Change Log (to be removed by RFC Editor before publication)
Changes up to the first Working Group Last Call draft are summarized
in <http://tools.ietf.org/html/
draft-ietf-httpbis-p5-range-19#appendix-D>.
E.1. Since draft-ietf-httpbis-p5-range-19
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/358>: "ABNF list
expansion code problem"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/361>: "ABNF
requirements for recipients"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/367>: "reserve
'none' as byte range unit"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/368>: "note
introduction of new IANA registries as normative changes"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/369>: "range units
vs leading zeroes vs size"
E.2. Since draft-ietf-httpbis-p5-range-20
o Conformance criteria and considerations regarding error handling
are now defined in Part 1.
E.3. Since draft-ietf-httpbis-p5-range-21
Closed issues:
o <http://tools.ietf.org/wg/httpbis/trac/ticket/175>: "Security
consideration: range flooding"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/223>: "Allowing
heuristic caching for new status codes"
o <http://tools.ietf.org/wg/httpbis/trac/ticket/311>: "Add
limitations to Range to reduce its use as a denial-of-service
tool"
Index Index
2 2
206 Partial Content (status code) 10 206 Partial Content (status code) 10
4 4
416 Range Not Satisfiable (status code) 15 416 Range Not Satisfiable (status code) 15
A A
Accept-Ranges header field 7 Accept-Ranges header field 7
skipping to change at page 24, line 33 skipping to change at page 24, line 43
byte-ranges-specifier 5 byte-ranges-specifier 5
bytes-unit 5 bytes-unit 5
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 9
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 5, 7
Range 7 Range 8
range-unit 5 range-unit 5
ranges-specifier 5 ranges-specifier 5
suffix-byte-range-spec 6 suffix-byte-range-spec 6
suffix-length 6 suffix-length 6
unsatisfied-range 12 unsatisfied-range 12
I I
If-Range header field 9 If-Range header field 9
M M
Media Type Media Type
multipart/byteranges 18 multipart/byteranges 18, 21
multipart/x-byteranges 20 multipart/x-byteranges 19
multipart/byteranges Media Type 18 multipart/byteranges Media Type 18, 21
multipart/x-byteranges Media Type 20 multipart/x-byteranges Media Type 21
R R
Range header field 7 Range header field 8
Authors' Addresses Authors' Addresses
Roy T. Fielding (editor) Roy T. Fielding (editor)
Adobe Systems Incorporated Adobe Systems Incorporated
345 Park Ave 345 Park Ave
San Jose, CA 95110 San Jose, CA 95110
USA USA
EMail: fielding@gbiv.com EMail: fielding@gbiv.com
 End of changes. 82 change blocks. 
311 lines changed or deleted 270 lines changed or added

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