draft-ietf-httpbis-p3-payload-01.txt		draft-ietf-httpbis-p3-payload-02.txt
	Network Working Group R. Fielding, Ed.		Network Working Group R. Fielding, Ed.
	Internet-Draft Day Software		Internet-Draft Day Software
	Obsoletes: 2616 (if approved) J. Gettys		Obsoletes: 2616 (if approved) J. Gettys
	Intended status: Standards Track One Laptop per Child		Intended status: Standards Track One Laptop per Child
	Expires: July 15, 2008 J. Mogul		Expires: August 27, 2008 J. Mogul
	HP		HP
	H. Frystyk		H. Frystyk
	Microsoft		Microsoft
	L. Masinter		L. Masinter
	Adobe Systems		Adobe Systems
	P. Leach		P. Leach
	Microsoft		Microsoft
	T. Berners-Lee		T. Berners-Lee
	W3C/MIT		W3C/MIT
	Y. Lafon, Ed.		Y. Lafon, Ed.
	W3C		W3C
	J. Reschke, Ed.		J. Reschke, Ed.
	greenbytes		greenbytes
	January 12, 2008		February 24, 2008
	HTTP/1.1, part 3: Message Payload and Content Negotiation		HTTP/1.1, part 3: Message Payload and Content Negotiation
	draft-ietf-httpbis-p3-payload-01		draft-ietf-httpbis-p3-payload-02
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 49		skipping to change at page 1, line 49
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	This Internet-Draft will expire on July 15, 2008.		This Internet-Draft will expire on August 27, 2008.
	Copyright Notice		Copyright Notice
	Copyright (C) The IETF Trust (2008).		Copyright (C) The IETF Trust (2008).
	Abstract		Abstract
	The Hypertext Transfer Protocol (HTTP) is an application-level		The Hypertext Transfer Protocol (HTTP) is an application-level
	protocol for distributed, collaborative, hypermedia information		protocol for distributed, collaborative, hypermedia information
	systems. HTTP has been in use by the World Wide Web global		systems. HTTP has been in use by the World Wide Web global
	skipping to change at page 3, line 9		skipping to change at page 3, line 9
	This draft incorporates those issue resolutions that were either		This draft incorporates those issue resolutions that were either
	collected in the original RFC2616 errata list		collected in the original RFC2616 errata list
	(<http://purl.org/NET/http-errata>), or which were agreed upon on the		(<http://purl.org/NET/http-errata>), or which were agreed upon on the
	mailing list between October 2006 and November 2007 (as published in		mailing list between October 2006 and November 2007 (as published in
	"draft-lafon-rfc2616bis-03").		"draft-lafon-rfc2616bis-03").
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
	1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 5		1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 5
	2. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 5		2. Notational Conventions and Generic Grammar . . . . . . . . . . 5
	2.1. Character Sets . . . . . . . . . . . . . . . . . . . . . . 5		3. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 6
	2.1.1. Missing Charset . . . . . . . . . . . . . . . . . . . 6		3.1. Character Sets . . . . . . . . . . . . . . . . . . . . . . 6
	2.2. Content Codings . . . . . . . . . . . . . . . . . . . . . 7		3.1.1. Missing Charset . . . . . . . . . . . . . . . . . . . 7
	2.3. Media Types . . . . . . . . . . . . . . . . . . . . . . . 8		3.2. Content Codings . . . . . . . . . . . . . . . . . . . . . 7
	2.3.1. Canonicalization and Text Defaults . . . . . . . . . . 9		3.3. Media Types . . . . . . . . . . . . . . . . . . . . . . . 9
	2.3.2. Multipart Types . . . . . . . . . . . . . . . . . . . 9		3.3.1. Canonicalization and Text Defaults . . . . . . . . . . 9
	2.4. Quality Values . . . . . . . . . . . . . . . . . . . . . . 10		3.3.2. Multipart Types . . . . . . . . . . . . . . . . . . . 10
	2.5. Language Tags . . . . . . . . . . . . . . . . . . . . . . 10		3.4. Quality Values . . . . . . . . . . . . . . . . . . . . . . 11
	3. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11		3.5. Language Tags . . . . . . . . . . . . . . . . . . . . . . 11
	3.1. Entity Header Fields . . . . . . . . . . . . . . . . . . . 11		4. Entity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	3.2. Entity Body . . . . . . . . . . . . . . . . . . . . . . . 12		4.1. Entity Header Fields . . . . . . . . . . . . . . . . . . . 12
	3.2.1. Type . . . . . . . . . . . . . . . . . . . . . . . . . 12		4.2. Entity Body . . . . . . . . . . . . . . . . . . . . . . . 12
	3.2.2. Entity Length . . . . . . . . . . . . . . . . . . . . 12		4.2.1. Type . . . . . . . . . . . . . . . . . . . . . . . . . 13
	4. Content Negotiation . . . . . . . . . . . . . . . . . . . . . 13		4.2.2. Entity Length . . . . . . . . . . . . . . . . . . . . 13
	4.1. Server-driven Negotiation . . . . . . . . . . . . . . . . 13		5. Content Negotiation . . . . . . . . . . . . . . . . . . . . . 13
	4.2. Agent-driven Negotiation . . . . . . . . . . . . . . . . . 14		5.1. Server-driven Negotiation . . . . . . . . . . . . . . . . 14
	4.3. Transparent Negotiation . . . . . . . . . . . . . . . . . 15		5.2. Agent-driven Negotiation . . . . . . . . . . . . . . . . . 15
	5. Header Field Definitions . . . . . . . . . . . . . . . . . . . 15		5.3. Transparent Negotiation . . . . . . . . . . . . . . . . . 16
	5.1. Accept . . . . . . . . . . . . . . . . . . . . . . . . . . 16		6. Header Field Definitions . . . . . . . . . . . . . . . . . . . 16
	5.2. Accept-Charset . . . . . . . . . . . . . . . . . . . . . . 18		6.1. Accept . . . . . . . . . . . . . . . . . . . . . . . . . . 16
	5.3. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 18		6.2. Accept-Charset . . . . . . . . . . . . . . . . . . . . . . 18
	5.4. Accept-Language . . . . . . . . . . . . . . . . . . . . . 20		6.3. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 19
	5.5. Content-Encoding . . . . . . . . . . . . . . . . . . . . . 21		6.4. Accept-Language . . . . . . . . . . . . . . . . . . . . . 20
	5.6. Content-Language . . . . . . . . . . . . . . . . . . . . . 22		6.5. Content-Encoding . . . . . . . . . . . . . . . . . . . . . 22
	5.7. Content-Location . . . . . . . . . . . . . . . . . . . . . 22		6.6. Content-Language . . . . . . . . . . . . . . . . . . . . . 22
	5.8. Content-MD5 . . . . . . . . . . . . . . . . . . . . . . . 23		6.7. Content-Location . . . . . . . . . . . . . . . . . . . . . 23
	5.9. Content-Type . . . . . . . . . . . . . . . . . . . . . . . 24		6.8. Content-MD5 . . . . . . . . . . . . . . . . . . . . . . . 24
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25		6.9. Content-Type . . . . . . . . . . . . . . . . . . . . . . . 25
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 25		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
	7.1. Privacy Issues Connected to Accept Headers . . . . . . . . 25		8. Security Considerations . . . . . . . . . . . . . . . . . . . 26
	7.2. Content-Disposition Issues . . . . . . . . . . . . . . . . 26		8.1. Privacy Issues Connected to Accept Headers . . . . . . . . 26
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26		8.2. Content-Disposition Issues . . . . . . . . . . . . . . . . 27
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26		9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
	9.1. Normative References . . . . . . . . . . . . . . . . . . . 26		10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
	9.2. Informative References . . . . . . . . . . . . . . . . . . 28		10.1. Normative References . . . . . . . . . . . . . . . . . . . 27
			10.2. Informative References . . . . . . . . . . . . . . . . . . 29
	Appendix A. Differences Between HTTP Entities and RFC 2045		Appendix A. Differences Between HTTP Entities and RFC 2045
	Entities . . . . . . . . . . . . . . . . . . . . . . 29		Entities . . . . . . . . . . . . . . . . . . . . . . 30
	A.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . . 29		A.1. MIME-Version . . . . . . . . . . . . . . . . . . . . . . . 30
	A.2. Conversion to Canonical Form . . . . . . . . . . . . . . . 30		A.2. Conversion to Canonical Form . . . . . . . . . . . . . . . 30
	A.3. Introduction of Content-Encoding . . . . . . . . . . . . . 30		A.3. Introduction of Content-Encoding . . . . . . . . . . . . . 31
	A.4. No Content-Transfer-Encoding . . . . . . . . . . . . . . . 30		A.4. No Content-Transfer-Encoding . . . . . . . . . . . . . . . 31
	A.5. Introduction of Transfer-Encoding . . . . . . . . . . . . 31		A.5. Introduction of Transfer-Encoding . . . . . . . . . . . . 31
	A.6. MHTML and Line Length Limitations . . . . . . . . . . . . 31		A.6. MHTML and Line Length Limitations . . . . . . . . . . . . 32
	Appendix B. Additional Features . . . . . . . . . . . . . . . . . 31		Appendix B. Additional Features . . . . . . . . . . . . . . . . . 32
	B.1. Content-Disposition . . . . . . . . . . . . . . . . . . . 31		B.1. Content-Disposition . . . . . . . . . . . . . . . . . . . 32
	Appendix C. Compatibility with Previous Versions . . . . . . . . 32		Appendix C. Compatibility with Previous Versions . . . . . . . . 33
	C.1. Changes from RFC 2068 . . . . . . . . . . . . . . . . . . 32		C.1. Changes from RFC 2068 . . . . . . . . . . . . . . . . . . 33
	C.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 33		C.2. Changes from RFC 2616 . . . . . . . . . . . . . . . . . . 33
	Appendix D. Change Log (to be removed by RFC Editor before		Appendix D. Change Log (to be removed by RFC Editor before
	publication) . . . . . . . . . . . . . . . . . . . . 33		publication) . . . . . . . . . . . . . . . . . . . . 34
	D.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . . 33		D.1. Since RFC2616 . . . . . . . . . . . . . . . . . . . . . . 34
	D.2. Since draft-ietf-httpbis-p3-payload-00 . . . . . . . . . . 33		D.2. Since draft-ietf-httpbis-p3-payload-00 . . . . . . . . . . 34
	Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34		D.3. Since draft-ietf-httpbis-p3-payload-01 . . . . . . . . . . 35
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36		Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
	Intellectual Property and Copyright Statements . . . . . . . . . . 39		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37
			Intellectual Property and Copyright Statements . . . . . . . . . . 40
	1. Introduction		1. Introduction
	This document defines HTTP/1.1 message payloads (a.k.a., content),		This document defines HTTP/1.1 message payloads (a.k.a., content),
	the associated metadata header fields that define how the payload is		the associated metadata header fields that define how the payload is
	intended to be interpreted by a recipient, the request header fields		intended to be interpreted by a recipient, the request header fields
	that may influence content selection, and the various selection		that may influence content selection, and the various selection
	algorithms that are collectively referred to as HTTP content		algorithms that are collectively referred to as HTTP content
	negotiation.		negotiation.
	skipping to change at page 5, line 39		skipping to change at page 5, line 39
	An implementation is not compliant if it fails to satisfy one or more		An implementation is not compliant if it fails to satisfy one or more
	of the MUST or REQUIRED level requirements for the protocols it		of the MUST or REQUIRED level requirements for the protocols it
	implements. An implementation that satisfies all the MUST or		implements. An implementation that satisfies all the MUST or
	REQUIRED level and all the SHOULD level requirements for its		REQUIRED level and all the SHOULD level requirements for its
	protocols is said to be "unconditionally compliant"; one that		protocols is said to be "unconditionally compliant"; one that
	satisfies all the MUST level requirements but not all the SHOULD		satisfies all the MUST level requirements but not all the SHOULD
	level requirements for its protocols is said to be "conditionally		level requirements for its protocols is said to be "conditionally
	compliant."		compliant."
	2. Protocol Parameters		2. Notational Conventions and Generic Grammar
	2.1. Character Sets		This specification uses the ABNF syntax defined in Section 2.1 of
			[Part1] and the core rules defined in Section 2.2 of [Part1]:
			[[abnf.dep: ABNF syntax and basic rules will be adopted from RFC
			5234, see <http://tools.ietf.org/wg/httpbis/trac/ticket/36>.]]
			ALPHA = <ALPHA, defined in [Part1], Section 2.2>
			DIGIT = <DIGIT, defined in [Part1], Section 2.2>
			OCTET = <OCTET, defined in [Part1], Section 2.2>
			quoted-string = <quoted-string, defined in [Part1], Section 2.2>
			token = <token, defined in [Part1], Section 2.2>
			The ABNF rules below are defined in other parts:
			absoluteURI = <absoluteURI, defined in [Part1], Section 3.2.1>
			Content-Length = <Content-Length, defined in [Part1], Section 8.2>
			relativeURI = <relativeURI, defined in [Part1], Section 3.2.1>
			message-header = <message-header, defined in [Part1], Section 4.2>
			Allow = <Allow, defined in [Part2], Section 10.1>
			Last-Modified = <Last-Modified, defined in [Part4], Section 7.6>
			Content-Range = <Content-Range, defined in [Part5], Section 6.2>
			Expires = <Expires, defined in [Part6], Section 16.3>
			3. Protocol Parameters
			3.1. Character Sets
	HTTP uses the same definition of the term "character set" as that		HTTP uses the same definition of the term "character set" as that
	described for MIME:		described for MIME:
	The term "character set" is used in this document to refer to a		The term "character set" is used in this document to refer to a
	method used with one or more tables to convert a sequence of octets		method used with one or more tables to convert a sequence of octets
	into a sequence of characters. Note that unconditional conversion in		into a sequence of characters. Note that unconditional conversion in
	the other direction is not required, in that not all characters may		the other direction is not required, in that not all characters may
	be available in a given character set and a character set may provide		be available in a given character set and a character set may provide
	more than one sequence of octets to represent a particular character.		more than one sequence of octets to represent a particular character.
	skipping to change at page 6, line 39		skipping to change at page 7, line 26
	HTTP uses charset in two contexts: within an Accept-Charset request		HTTP uses charset in two contexts: within an Accept-Charset request
	header (in which the charset value is an unquoted token) and as the		header (in which the charset value is an unquoted token) and as the
	value of a parameter in a Content-Type header (within a request or		value of a parameter in a Content-Type header (within a request or
	response), in which case the parameter value of the charset parameter		response), in which case the parameter value of the charset parameter
	may be quoted.		may be quoted.
	Implementors should be aware of IETF character set requirements		Implementors should be aware of IETF character set requirements
	[RFC3629] [RFC2277].		[RFC3629] [RFC2277].
	2.1.1. Missing Charset		3.1.1. Missing Charset
	Some HTTP/1.0 software has interpreted a Content-Type header without		Some HTTP/1.0 software has interpreted a Content-Type header without
	charset parameter incorrectly to mean "recipient should guess."		charset parameter incorrectly to mean "recipient should guess."
	Senders wishing to defeat this behavior MAY include a charset		Senders wishing to defeat this behavior MAY include a charset
	parameter even when the charset is ISO-8859-1 ([ISO-8859-1]) and		parameter even when the charset is ISO-8859-1 ([ISO-8859-1]) and
	SHOULD do so when it is known that it will not confuse the recipient.		SHOULD do so when it is known that it will not confuse the recipient.
	Unfortunately, some older HTTP/1.0 clients did not deal properly with		Unfortunately, some older HTTP/1.0 clients did not deal properly with
	an explicit charset parameter. HTTP/1.1 recipients MUST respect the		an explicit charset parameter. HTTP/1.1 recipients MUST respect the
	charset label provided by the sender; and those user agents that have		charset label provided by the sender; and those user agents that have
	a provision to "guess" a charset MUST use the charset from the		a provision to "guess" a charset MUST use the charset from the
	content-type field if they support that charset, rather than the		content-type field if they support that charset, rather than the
	recipient's preference, when initially displaying a document. See		recipient's preference, when initially displaying a document. See
	Section 2.3.1.		Section 3.3.1.
	2.2. Content Codings		3.2. Content Codings
	Content coding values indicate an encoding transformation that has		Content coding values indicate an encoding transformation that has
	been or can be applied to an entity. Content codings are primarily		been or can be applied to an entity. Content codings are primarily
	used to allow a document to be compressed or otherwise usefully		used to allow a document to be compressed or otherwise usefully
	transformed without losing the identity of its underlying media type		transformed without losing the identity of its underlying media type
	and without loss of information. Frequently, the entity is stored in		and without loss of information. Frequently, the entity is stored in
	coded form, transmitted directly, and only decoded by the recipient.		coded form, transmitted directly, and only decoded by the recipient.
	content-coding = token		content-coding = token
	All content-coding values are case-insensitive. HTTP/1.1 uses		All content-coding values are case-insensitive. HTTP/1.1 uses
	content-coding values in the Accept-Encoding (Section 5.3) and		content-coding values in the Accept-Encoding (Section 6.3) and
	Content-Encoding (Section 5.5) header fields. Although the value		Content-Encoding (Section 6.5) header fields. Although the value
	describes the content-coding, what is more important is that it		describes the content-coding, what is more important is that it
	indicates what decoding mechanism will be required to remove the		indicates what decoding mechanism will be required to remove the
	encoding.		encoding.
	The Internet Assigned Numbers Authority (IANA) acts as a registry for		The Internet Assigned Numbers Authority (IANA) acts as a registry for
	content-coding value tokens. Initially, the registry contains the		content-coding value tokens. Initially, the registry contains the
	following tokens:		following tokens:
	gzip		gzip
	skipping to change at page 8, line 18		skipping to change at page 9, line 5
	whatsoever. This content-coding is used only in the Accept-		whatsoever. This content-coding is used only in the Accept-
	Encoding header, and SHOULD NOT be used in the Content-Encoding		Encoding header, and SHOULD NOT be used in the Content-Encoding
	header.		header.
	New content-coding value tokens SHOULD be registered; to allow		New content-coding value tokens SHOULD be registered; to allow
	interoperability between clients and servers, specifications of the		interoperability between clients and servers, specifications of the
	content coding algorithms needed to implement a new value SHOULD be		content coding algorithms needed to implement a new value SHOULD be
	publicly available and adequate for independent implementation, and		publicly available and adequate for independent implementation, and
	conform to the purpose of content coding defined in this section.		conform to the purpose of content coding defined in this section.
	2.3. Media Types		3.3. Media Types
	HTTP uses Internet Media Types [RFC2046] in the Content-Type		HTTP uses Internet Media Types [RFC2046] in the Content-Type
	(Section 5.9) and Accept (Section 5.1) header fields in order to		(Section 6.9) and Accept (Section 6.1) header fields in order to
	provide open and extensible data typing and type negotiation.		provide open and extensible data typing and type negotiation.
	media-type = type "/" subtype *( ";" parameter )		media-type = type "/" subtype *( ";" parameter )
	type = token		type = token
	subtype = token		subtype = token
	Parameters MAY follow the type/subtype in the form of attribute/value		Parameters MAY follow the type/subtype in the form of attribute/value
	pairs.		pairs.
	parameter = attribute "=" value		parameter = attribute "=" value
	skipping to change at page 9, line 5		skipping to change at page 9, line 39
	Note that some older HTTP applications do not recognize media type		Note that some older HTTP applications do not recognize media type
	parameters. When sending data to older HTTP applications,		parameters. When sending data to older HTTP applications,
	implementations SHOULD only use media type parameters when they are		implementations SHOULD only use media type parameters when they are
	required by that type/subtype definition.		required by that type/subtype definition.
	Media-type values are registered with the Internet Assigned Number		Media-type values are registered with the Internet Assigned Number
	Authority (IANA). The media type registration process is outlined in		Authority (IANA). The media type registration process is outlined in
	[RFC4288]. Use of non-registered media types is discouraged.		[RFC4288]. Use of non-registered media types is discouraged.
	2.3.1. Canonicalization and Text Defaults		3.3.1. Canonicalization and Text Defaults
	Internet media types are registered with a canonical form. An		Internet media types are registered with a canonical form. An
	entity-body transferred via HTTP messages MUST be represented in the		entity-body transferred via HTTP messages MUST be represented in the
	appropriate canonical form prior to its transmission except for		appropriate canonical form prior to its transmission except for
	"text" types, as defined in the next paragraph.		"text" types, as defined in the next paragraph.
	When in canonical form, media subtypes of the "text" type use CRLF as		When in canonical form, media subtypes of the "text" type use CRLF as
	the text line break. HTTP relaxes this requirement and allows the		the text line break. HTTP relaxes this requirement and allows the
	transport of text media with plain CR or LF alone representing a line		transport of text media with plain CR or LF alone representing a line
	break when it is done consistently for an entire entity-body. HTTP		break when it is done consistently for an entire entity-body. HTTP
	skipping to change at page 9, line 31		skipping to change at page 10, line 16
	sequences are defined by that character set to represent the		sequences are defined by that character set to represent the
	equivalent of CR and LF for line breaks. This flexibility regarding		equivalent of CR and LF for line breaks. This flexibility regarding
	line breaks applies only to text media in the entity-body; a bare CR		line breaks applies only to text media in the entity-body; a bare CR
	or LF MUST NOT be substituted for CRLF within any of the HTTP control		or LF MUST NOT be substituted for CRLF within any of the HTTP control
	structures (such as header fields and multipart boundaries).		structures (such as header fields and multipart boundaries).
	If an entity-body is encoded with a content-coding, the underlying		If an entity-body is encoded with a content-coding, the underlying
	data MUST be in a form defined above prior to being encoded.		data MUST be in a form defined above prior to being encoded.
	The "charset" parameter is used with some media types to define the		The "charset" parameter is used with some media types to define the
	character set (Section 2.1) of the data. When no explicit charset		character set (Section 3.1) of the data. When no explicit charset
	parameter is provided by the sender, media subtypes of the "text"		parameter is provided by the sender, media subtypes of the "text"
	type are defined to have a default charset value of "ISO-8859-1" when		type are defined to have a default charset value of "ISO-8859-1" when
	received via HTTP. Data in character sets other than "ISO-8859-1" or		received via HTTP. Data in character sets other than "ISO-8859-1" or
	its subsets MUST be labeled with an appropriate charset value. See		its subsets MUST be labeled with an appropriate charset value. See
	Section 2.1.1 for compatibility problems.		Section 3.1.1 for compatibility problems.
	2.3.2. Multipart Types		3.3.2. Multipart Types
	MIME provides for a number of "multipart" types -- encapsulations of		MIME provides for a number of "multipart" types -- encapsulations of
	one or more entities within a single message-body. All multipart		one or more entities within a single message-body. All multipart
	types share a common syntax, as defined in Section 5.1.1 of		types share a common syntax, as defined in Section 5.1.1 of
	[RFC2046], and MUST include a boundary parameter as part of the media		[RFC2046], and MUST include a boundary parameter as part of the media
	type value. The message body is itself a protocol element and MUST		type value. The message body is itself a protocol element and MUST
	therefore use only CRLF to represent line breaks between body-parts.		therefore use only CRLF to represent line breaks between body-parts.
	Unlike in RFC 2046, the epilogue of any multipart message MUST be		Unlike in RFC 2046, the epilogue of any multipart message MUST be
	empty; HTTP applications MUST NOT transmit the epilogue (even if the		empty; HTTP applications MUST NOT transmit the epilogue (even if the
	original multipart contains an epilogue). These restrictions exist		original multipart contains an epilogue). These restrictions exist
	skipping to change at page 10, line 23		skipping to change at page 11, line 9
	In general, an HTTP user agent SHOULD follow the same or similar		In general, an HTTP user agent SHOULD follow the same or similar
	behavior as a MIME user agent would upon receipt of a multipart type.		behavior as a MIME user agent would upon receipt of a multipart type.
	If an application receives an unrecognized multipart subtype, the		If an application receives an unrecognized multipart subtype, the
	application MUST treat it as being equivalent to "multipart/mixed".		application MUST treat it as being equivalent to "multipart/mixed".
	Note: The "multipart/form-data" type has been specifically defined		Note: The "multipart/form-data" type has been specifically defined
	for carrying form data suitable for processing via the POST		for carrying form data suitable for processing via the POST
	request method, as described in [RFC2388].		request method, as described in [RFC2388].
	2.4. Quality Values		3.4. Quality Values
	HTTP content negotiation (Section 4) uses short "floating point"		HTTP content negotiation (Section 5) uses short "floating point"
	numbers to indicate the relative importance ("weight") of various		numbers to indicate the relative importance ("weight") of various
	negotiable parameters. A weight is normalized to a real number in		negotiable parameters. A weight is normalized to a real number in
	the range 0 through 1, where 0 is the minimum and 1 the maximum		the range 0 through 1, where 0 is the minimum and 1 the maximum
	value. If a parameter has a quality value of 0, then content with		value. If a parameter has a quality value of 0, then content with
	this parameter is `not acceptable' for the client. HTTP/1.1		this parameter is `not acceptable' for the client. HTTP/1.1
	applications MUST NOT generate more than three digits after the		applications MUST NOT generate more than three digits after the
	decimal point. User configuration of these values SHOULD also be		decimal point. User configuration of these values SHOULD also be
	limited in this fashion.		limited in this fashion.
	qvalue = ( "0" [ "." 0*3DIGIT ] )		qvalue = ( "0" [ "." 0*3DIGIT ] )
	| ( "1" [ "." 0*3("0") ] )		| ( "1" [ "." 0*3("0") ] )
	"Quality values" is a misnomer, since these values merely represent		"Quality values" is a misnomer, since these values merely represent
	relative degradation in desired quality.		relative degradation in desired quality.
	2.5. Language Tags		3.5. Language Tags
	A language tag identifies a natural language spoken, written, or		A language tag identifies a natural language spoken, written, or
	otherwise conveyed by human beings for communication of information		otherwise conveyed by human beings for communication of information
	to other human beings. Computer languages are explicitly excluded.		to other human beings. Computer languages are explicitly excluded.
	HTTP uses language tags within the Accept-Language and Content-		HTTP uses language tags within the Accept-Language and Content-
	Language fields.		Language fields.
	The syntax and registry of HTTP language tags is the same as that		The syntax and registry of HTTP language tags is the same as that
	defined by [RFC1766]. In summary, a language tag is composed of 1 or		defined by [RFC1766]. In summary, a language tag is composed of 1 or
	more parts: A primary language tag and a possibly empty series of		more parts: A primary language tag and a possibly empty series of
	skipping to change at page 11, line 20		skipping to change at page 12, line 6
	insensitive. The name space of language tags is administered by the		insensitive. The name space of language tags is administered by the
	IANA. Example tags include:		IANA. Example tags include:
	en, en-US, en-cockney, i-cherokee, x-pig-latin		en, en-US, en-cockney, i-cherokee, x-pig-latin
	where any two-letter primary-tag is an ISO-639 language abbreviation		where any two-letter primary-tag is an ISO-639 language abbreviation
	and any two-letter initial subtag is an ISO-3166 country code. (The		and any two-letter initial subtag is an ISO-3166 country code. (The
	last three tags above are not registered tags; all but the last are		last three tags above are not registered tags; all but the last are
	examples of tags which could be registered in future.)		examples of tags which could be registered in future.)
	3. Entity		4. Entity
	Request and Response messages MAY transfer an entity if not otherwise		Request and Response messages MAY transfer an entity if not otherwise
	restricted by the request method or response status code. An entity		restricted by the request method or response status code. An entity
	consists of entity-header fields and an entity-body, although some		consists of entity-header fields and an entity-body, although some
	responses will only include the entity-headers.		responses will only include the entity-headers.
	In this section, both sender and recipient refer to either the client		In this section, both sender and recipient refer to either the client
	or the server, depending on who sends and who receives the entity.		or the server, depending on who sends and who receives the entity.
	3.1. Entity Header Fields		4.1. Entity Header Fields
	Entity-header fields define metainformation about the entity-body or,		Entity-header fields define metainformation about the entity-body or,
	if no body is present, about the resource identified by the request.		if no body is present, about the resource identified by the request.
	entity-header = Allow ; [Part2], Section 10.1		entity-header = Allow ; [Part2], Section 10.1
	| Content-Encoding ; Section 5.5		| Content-Encoding ; Section 6.5
	| Content-Language ; Section 5.6		| Content-Language ; Section 6.6
	| Content-Length ; [Part1], Section 8.2		| Content-Length ; [Part1], Section 8.2
	| Content-Location ; Section 5.7		| Content-Location ; Section 6.7
	| Content-MD5 ; Section 5.8		| Content-MD5 ; Section 6.8
	| Content-Range ; [Part5], Section 5.2		| Content-Range ; [Part5], Section 6.2
	| Content-Type ; Section 5.9		| Content-Type ; Section 6.9
	| Expires ; [Part6], Section 15.3		| Expires ; [Part6], Section 16.3
	| Last-Modified ; [Part4], Section 6.6		| Last-Modified ; [Part4], Section 7.6
	| extension-header		| extension-header
	extension-header = message-header		extension-header = message-header
	The extension-header mechanism allows additional entity-header fields		The extension-header mechanism allows additional entity-header fields
	to be defined without changing the protocol, but these fields cannot		to be defined without changing the protocol, but these fields cannot
	be assumed to be recognizable by the recipient. Unrecognized header		be assumed to be recognizable by the recipient. Unrecognized header
	fields SHOULD be ignored by the recipient and MUST be forwarded by		fields SHOULD be ignored by the recipient and MUST be forwarded by
	transparent proxies.		transparent proxies.
	3.2. Entity Body		4.2. Entity Body
	The entity-body (if any) sent with an HTTP request or response is in		The entity-body (if any) sent with an HTTP request or response is in
	a format and encoding defined by the entity-header fields.		a format and encoding defined by the entity-header fields.
	entity-body = *OCTET		entity-body = *OCTET
	An entity-body is only present in a message when a message-body is		An entity-body is only present in a message when a message-body is
	present, as described in Section 4.3 of [Part1]. The entity-body is		present, as described in Section 4.3 of [Part1]. The entity-body is
	obtained from the message-body by decoding any Transfer-Encoding that		obtained from the message-body by decoding any Transfer-Encoding that
	might have been applied to ensure safe and proper transfer of the		might have been applied to ensure safe and proper transfer of the
	message.		message.
	3.2.1. Type		4.2.1. Type
	When an entity-body is included with a message, the data type of that		When an entity-body is included with a message, the data type of that
	body is determined via the header fields Content-Type and Content-		body is determined via the header fields Content-Type and Content-
	Encoding. These define a two-layer, ordered encoding model:		Encoding. These define a two-layer, ordered encoding model:
	entity-body := Content-Encoding( Content-Type( data ) )		entity-body := Content-Encoding( Content-Type( data ) )
	Content-Type specifies the media type of the underlying data.		Content-Type specifies the media type of the underlying data.
	Content-Encoding may be used to indicate any additional content		Content-Encoding may be used to indicate any additional content
	codings applied to the data, usually for the purpose of data		codings applied to the data, usually for the purpose of data
	skipping to change at page 12, line 42		skipping to change at page 13, line 29
	no default encoding.		no default encoding.
	Any HTTP/1.1 message containing an entity-body SHOULD include a		Any HTTP/1.1 message containing an entity-body SHOULD include a
	Content-Type header field defining the media type of that body. If		Content-Type header field defining the media type of that body. If
	and only if the media type is not given by a Content-Type field, the		and only if the media type is not given by a Content-Type field, the
	recipient MAY attempt to guess the media type via inspection of its		recipient MAY attempt to guess the media type via inspection of its
	content and/or the name extension(s) of the URI used to identify the		content and/or the name extension(s) of the URI used to identify the
	resource. If the media type remains unknown, the recipient SHOULD		resource. If the media type remains unknown, the recipient SHOULD
	treat it as type "application/octet-stream".		treat it as type "application/octet-stream".
	3.2.2. Entity Length		4.2.2. Entity Length
	The entity-length of a message is the length of the message-body		The entity-length of a message is the length of the message-body
	before any transfer-codings have been applied. Section 4.4 of		before any transfer-codings have been applied. Section 4.4 of
	[Part1] defines how the transfer-length of a message-body is		[Part1] defines how the transfer-length of a message-body is
	determined.		determined.
	4. Content Negotiation		5. Content Negotiation
	Most HTTP responses include an entity which contains information for		Most HTTP responses include an entity which contains information for
	interpretation by a human user. Naturally, it is desirable to supply		interpretation by a human user. Naturally, it is desirable to supply
	the user with the "best available" entity corresponding to the		the user with the "best available" entity corresponding to the
	request. Unfortunately for servers and caches, not all users have		request. Unfortunately for servers and caches, not all users have
	the same preferences for what is "best," and not all user agents are		the same preferences for what is "best," and not all user agents are
	equally capable of rendering all entity types. For that reason, HTTP		equally capable of rendering all entity types. For that reason, HTTP
	has provisions for several mechanisms for "content negotiation" --		has provisions for several mechanisms for "content negotiation" --
	the process of selecting the best representation for a given response		the process of selecting the best representation for a given response
	when there are multiple representations available.		when there are multiple representations available.
	skipping to change at page 13, line 33		skipping to change at page 14, line 17
	including error responses.		including error responses.
	There are two kinds of content negotiation which are possible in		There are two kinds of content negotiation which are possible in
	HTTP: server-driven and agent-driven negotiation. These two kinds of		HTTP: server-driven and agent-driven negotiation. These two kinds of
	negotiation are orthogonal and thus may be used separately or in		negotiation are orthogonal and thus may be used separately or in
	combination. One method of combination, referred to as transparent		combination. One method of combination, referred to as transparent
	negotiation, occurs when a cache uses the agent-driven negotiation		negotiation, occurs when a cache uses the agent-driven negotiation
	information provided by the origin server in order to provide server-		information provided by the origin server in order to provide server-
	driven negotiation for subsequent requests.		driven negotiation for subsequent requests.
	4.1. Server-driven Negotiation		5.1. Server-driven Negotiation
	If the selection of the best representation for a response is made by		If the selection of the best representation for a response is made by
	an algorithm located at the server, it is called server-driven		an algorithm located at the server, it is called server-driven
	negotiation. Selection is based on the available representations of		negotiation. Selection is based on the available representations of
	the response (the dimensions over which it can vary; e.g. language,		the response (the dimensions over which it can vary; e.g. language,
	content-coding, etc.) and the contents of particular header fields in		content-coding, etc.) and the contents of particular header fields in
	the request message or on other information pertaining to the request		the request message or on other information pertaining to the request
	(such as the network address of the client).		(such as the network address of the client).
	Server-driven negotiation is advantageous when the algorithm for		Server-driven negotiation is advantageous when the algorithm for
	skipping to change at page 14, line 26		skipping to change at page 15, line 10
	violation of the user's privacy.		violation of the user's privacy.
	3. It complicates the implementation of an origin server and the		3. It complicates the implementation of an origin server and the
	algorithms for generating responses to a request.		algorithms for generating responses to a request.
	4. It may limit a public cache's ability to use the same response		4. It may limit a public cache's ability to use the same response
	for multiple user's requests.		for multiple user's requests.
	HTTP/1.1 includes the following request-header fields for enabling		HTTP/1.1 includes the following request-header fields for enabling
	server-driven negotiation through description of user agent		server-driven negotiation through description of user agent
	capabilities and user preferences: Accept (Section 5.1), Accept-		capabilities and user preferences: Accept (Section 6.1), Accept-
	Charset (Section 5.2), Accept-Encoding (Section 5.3), Accept-Language		Charset (Section 6.2), Accept-Encoding (Section 6.3), Accept-Language
	(Section 5.4), and User-Agent (Section 10.9 of [Part2]). However, an		(Section 6.4), and User-Agent (Section 10.9 of [Part2]). However, an
	origin server is not limited to these dimensions and MAY vary the		origin server is not limited to these dimensions and MAY vary the
	response based on any aspect of the request, including information		response based on any aspect of the request, including information
	outside the request-header fields or within extension header fields		outside the request-header fields or within extension header fields
	not defined by this specification.		not defined by this specification.
	The Vary header field (Section 15.5 of [Part6]) can be used to		The Vary header field (Section 16.5 of [Part6]) can be used to
	express the parameters the server uses to select a representation		express the parameters the server uses to select a representation
	that is subject to server-driven negotiation.		that is subject to server-driven negotiation.
	4.2. Agent-driven Negotiation		5.2. Agent-driven Negotiation
	With agent-driven negotiation, selection of the best representation		With agent-driven negotiation, selection of the best representation
	for a response is performed by the user agent after receiving an		for a response is performed by the user agent after receiving an
	initial response from the origin server. Selection is based on a		initial response from the origin server. Selection is based on a
	list of the available representations of the response included within		list of the available representations of the response included within
	the header fields or entity-body of the initial response, with each		the header fields or entity-body of the initial response, with each
	representation identified by its own URI. Selection from among the		representation identified by its own URI. Selection from among the
	representations may be performed automatically (if the user agent is		representations may be performed automatically (if the user agent is
	capable of doing so) or manually by the user selecting from a		capable of doing so) or manually by the user selecting from a
	generated (possibly hypertext) menu.		generated (possibly hypertext) menu.
	skipping to change at page 15, line 20		skipping to change at page 16, line 5
	this specification does not define any mechanism for supporting		this specification does not define any mechanism for supporting
	automatic selection, though it also does not prevent any such		automatic selection, though it also does not prevent any such
	mechanism from being developed as an extension and used within		mechanism from being developed as an extension and used within
	HTTP/1.1.		HTTP/1.1.
	HTTP/1.1 defines the 300 (Multiple Choices) and 406 (Not Acceptable)		HTTP/1.1 defines the 300 (Multiple Choices) and 406 (Not Acceptable)
	status codes for enabling agent-driven negotiation when the server is		status codes for enabling agent-driven negotiation when the server is
	unwilling or unable to provide a varying response using server-driven		unwilling or unable to provide a varying response using server-driven
	negotiation.		negotiation.
	4.3. Transparent Negotiation		5.3. Transparent Negotiation
	Transparent negotiation is a combination of both server-driven and		Transparent negotiation is a combination of both server-driven and
	agent-driven negotiation. When a cache is supplied with a form of		agent-driven negotiation. When a cache is supplied with a form of
	the list of available representations of the response (as in agent-		the list of available representations of the response (as in agent-
	driven negotiation) and the dimensions of variance are completely		driven negotiation) and the dimensions of variance are completely
	understood by the cache, then the cache becomes capable of performing		understood by the cache, then the cache becomes capable of performing
	server-driven negotiation on behalf of the origin server for		server-driven negotiation on behalf of the origin server for
	subsequent requests on that resource.		subsequent requests on that resource.
	Transparent negotiation has the advantage of distributing the		Transparent negotiation has the advantage of distributing the
	negotiation work that would otherwise be required of the origin		negotiation work that would otherwise be required of the origin
	server and also removing the second request delay of agent-driven		server and also removing the second request delay of agent-driven
	negotiation when the cache is able to correctly guess the right		negotiation when the cache is able to correctly guess the right
	response.		response.
	This specification does not define any mechanism for transparent		This specification does not define any mechanism for transparent
	negotiation, though it also does not prevent any such mechanism from		negotiation, though it also does not prevent any such mechanism from
	being developed as an extension that could be used within HTTP/1.1.		being developed as an extension that could be used within HTTP/1.1.
	5. Header Field Definitions		6. Header Field Definitions
	This section defines the syntax and semantics of HTTP/1.1 header		This section defines the syntax and semantics of HTTP/1.1 header
	fields related to the payload of messages.		fields related to the payload of messages.
	For entity-header fields, both sender and recipient refer to either		For entity-header fields, both sender and recipient refer to either
	the client or the server, depending on who sends and who receives the		the client or the server, depending on who sends and who receives the
	entity.		entity.
	5.1. Accept		6.1. Accept
	The Accept request-header field can be used to specify certain media		The Accept request-header field can be used to specify certain media
	types which are acceptable for the response. Accept headers can be		types which are acceptable for the response. Accept headers can be
	used to indicate that the request is specifically limited to a small		used to indicate that the request is specifically limited to a small
	set of desired types, as in the case of a request for an in-line		set of desired types, as in the case of a request for an in-line
	image.		image.
	Accept = "Accept" ":"		Accept = "Accept" ":"
	#( media-range [ accept-params ] )		#( media-range [ accept-params ] )
	skipping to change at page 16, line 33		skipping to change at page 17, line 14
	The asterisk "*" character is used to group media types into ranges,		The asterisk "*" character is used to group media types into ranges,
	with "*/*" indicating all media types and "type/*" indicating all		with "*/*" indicating all media types and "type/*" indicating all
	subtypes of that type. The media-range MAY include media type		subtypes of that type. The media-range MAY include media type
	parameters that are applicable to that range.		parameters that are applicable to that range.
	Each media-range MAY be followed by one or more accept-params,		Each media-range MAY be followed by one or more accept-params,
	beginning with the "q" parameter for indicating a relative quality		beginning with the "q" parameter for indicating a relative quality
	factor. The first "q" parameter (if any) separates the media-range		factor. The first "q" parameter (if any) separates the media-range
	parameter(s) from the accept-params. Quality factors allow the user		parameter(s) from the accept-params. Quality factors allow the user
	or user agent to indicate the relative degree of preference for that		or user agent to indicate the relative degree of preference for that
	media-range, using the qvalue scale from 0 to 1 (Section 2.4). The		media-range, using the qvalue scale from 0 to 1 (Section 3.4). The
	default value is q=1.		default value is q=1.
	Note: Use of the "q" parameter name to separate media type		Note: Use of the "q" parameter name to separate media type
	parameters from Accept extension parameters is due to historical		parameters from Accept extension parameters is due to historical
	practice. Although this prevents any media type parameter named		practice. Although this prevents any media type parameter named
	"q" from being used with a media range, such an event is believed		"q" from being used with a media range, such an event is believed
	to be unlikely given the lack of any "q" parameters in the IANA		to be unlikely given the lack of any "q" parameters in the IANA
	media type registry and the rare usage of any media type		media type registry and the rare usage of any media type
	parameters in Accept. Future media types are discouraged from		parameters in Accept. Future media types are discouraged from
	registering any parameter named "q".		registering any parameter named "q".
	skipping to change at page 18, line 5		skipping to change at page 18, line 34
	text/plain = 0.3		text/plain = 0.3
	image/jpeg = 0.5		image/jpeg = 0.5
	text/html;level=2 = 0.4		text/html;level=2 = 0.4
	text/html;level=3 = 0.7		text/html;level=3 = 0.7
	Note: A user agent might be provided with a default set of quality		Note: A user agent might be provided with a default set of quality
	values for certain media ranges. However, unless the user agent is a		values for certain media ranges. However, unless the user agent is a
	closed system which cannot interact with other rendering agents, this		closed system which cannot interact with other rendering agents, this
	default set ought to be configurable by the user.		default set ought to be configurable by the user.
	5.2. Accept-Charset		6.2. Accept-Charset
	The Accept-Charset request-header field can be used to indicate what		The Accept-Charset request-header field can be used to indicate what
	character sets are acceptable for the response. This field allows		character sets are acceptable for the response. This field allows
	clients capable of understanding more comprehensive or special-		clients capable of understanding more comprehensive or special-
	purpose character sets to signal that capability to a server which is		purpose character sets to signal that capability to a server which is
	capable of representing documents in those character sets.		capable of representing documents in those character sets.
	Accept-Charset = "Accept-Charset" ":"		Accept-Charset = "Accept-Charset" ":"
	1#( ( charset | "*" ) [ ";" "q" "=" qvalue ] )		1#( ( charset | "*" ) [ ";" "q" "=" qvalue ] )
	Character set values are described in Section 2.1. Each charset MAY		Character set values are described in Section 3.1. Each charset MAY
	be given an associated quality value which represents the user's		be given an associated quality value which represents the user's
	preference for that charset. The default value is q=1. An example		preference for that charset. The default value is q=1. An example
	is		is
	Accept-Charset: iso-8859-5, unicode-1-1;q=0.8		Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
	The special value "*", if present in the Accept-Charset field,		The special value "*", if present in the Accept-Charset field,
	matches every character set (including ISO-8859-1) which is not		matches every character set (including ISO-8859-1) which is not
	mentioned elsewhere in the Accept-Charset field. If no "*" is		mentioned elsewhere in the Accept-Charset field. If no "*" is
	present in an Accept-Charset field, then all character sets not		present in an Accept-Charset field, then all character sets not
	explicitly mentioned get a quality value of 0, except for ISO-8859-1,		explicitly mentioned get a quality value of 0, except for ISO-8859-1,
	which gets a quality value of 1 if not explicitly mentioned.		which gets a quality value of 1 if not explicitly mentioned.
	If no Accept-Charset header is present, the default is that any		If no Accept-Charset header is present, the default is that any
	character set is acceptable. If an Accept-Charset header is present,		character set is acceptable. If an Accept-Charset header is present,
	and if the server cannot send a response which is acceptable		and if the server cannot send a response which is acceptable
	skipping to change at page 18, line 37		skipping to change at page 19, line 18
	explicitly mentioned get a quality value of 0, except for ISO-8859-1,		explicitly mentioned get a quality value of 0, except for ISO-8859-1,
	which gets a quality value of 1 if not explicitly mentioned.		which gets a quality value of 1 if not explicitly mentioned.
	If no Accept-Charset header is present, the default is that any		If no Accept-Charset header is present, the default is that any
	character set is acceptable. If an Accept-Charset header is present,		character set is acceptable. If an Accept-Charset header is present,
	and if the server cannot send a response which is acceptable		and if the server cannot send a response which is acceptable
	according to the Accept-Charset header, then the server SHOULD send		according to the Accept-Charset header, then the server SHOULD send
	an error response with the 406 (Not Acceptable) status code, though		an error response with the 406 (Not Acceptable) status code, though
	the sending of an unacceptable response is also allowed.		the sending of an unacceptable response is also allowed.
	5.3. Accept-Encoding		6.3. Accept-Encoding
	The Accept-Encoding request-header field is similar to Accept, but		The Accept-Encoding request-header field is similar to Accept, but
	restricts the content-codings (Section 2.2) that are acceptable in		restricts the content-codings (Section 3.2) that are acceptable in
	the response.		the response.
	Accept-Encoding = "Accept-Encoding" ":"		Accept-Encoding = "Accept-Encoding" ":"
	#( codings [ ";" "q" "=" qvalue ] )		#( codings [ ";" "q" "=" qvalue ] )
	codings = ( content-coding | "*" )		codings = ( content-coding | "*" )
	Examples of its use are:		Examples of its use are:
	Accept-Encoding: compress, gzip		Accept-Encoding: compress, gzip
	Accept-Encoding:		Accept-Encoding:
	Accept-Encoding: *		Accept-Encoding: *
	Accept-Encoding: compress;q=0.5, gzip;q=1.0		Accept-Encoding: compress;q=0.5, gzip;q=1.0
	Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0		Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
	A server tests whether a content-coding is acceptable, according to		A server tests whether a content-coding is acceptable, according to
	an Accept-Encoding field, using these rules:		an Accept-Encoding field, using these rules:
	1. If the content-coding is one of the content-codings listed in the		1. If the content-coding is one of the content-codings listed in the
	Accept-Encoding field, then it is acceptable, unless it is		Accept-Encoding field, then it is acceptable, unless it is
	accompanied by a qvalue of 0. (As defined in Section 2.4, a		accompanied by a qvalue of 0. (As defined in Section 3.4, a
	qvalue of 0 means "not acceptable.")		qvalue of 0 means "not acceptable.")
	2. The special "*" symbol in an Accept-Encoding field matches any		2. The special "*" symbol in an Accept-Encoding field matches any
	available content-coding not explicitly listed in the header		available content-coding not explicitly listed in the header
	field.		field.
	3. If multiple content-codings are acceptable, then the acceptable		3. If multiple content-codings are acceptable, then the acceptable
	content-coding with the highest non-zero qvalue is preferred.		content-coding with the highest non-zero qvalue is preferred.
	4. The "identity" content-coding is always acceptable, unless		4. The "identity" content-coding is always acceptable, unless
	skipping to change at page 20, line 5		skipping to change at page 20, line 36
	codings commonly understood by HTTP/1.0 clients (i.e., "gzip" and		codings commonly understood by HTTP/1.0 clients (i.e., "gzip" and
	"compress") are preferred; some older clients improperly display		"compress") are preferred; some older clients improperly display
	messages sent with other content-codings. The server might also		messages sent with other content-codings. The server might also
	make this decision based on information about the particular user-		make this decision based on information about the particular user-
	agent or client.		agent or client.
	Note: Most HTTP/1.0 applications do not recognize or obey qvalues		Note: Most HTTP/1.0 applications do not recognize or obey qvalues
	associated with content-codings. This means that qvalues will not		associated with content-codings. This means that qvalues will not
	work and are not permitted with x-gzip or x-compress.		work and are not permitted with x-gzip or x-compress.
	5.4. Accept-Language		6.4. Accept-Language
	The Accept-Language request-header field is similar to Accept, but		The Accept-Language request-header field is similar to Accept, but
	restricts the set of natural languages that are preferred as a		restricts the set of natural languages that are preferred as a
	response to the request. Language tags are defined in Section 2.5.		response to the request. Language tags are defined in Section 3.5.
	Accept-Language = "Accept-Language" ":"		Accept-Language = "Accept-Language" ":"
	1#( language-range [ ";" "q" "=" qvalue ] )		1#( language-range [ ";" "q" "=" qvalue ] )
	language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" )		language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" )
	Each language-range MAY be given an associated quality value which		Each language-range MAY be given an associated quality value which
	represents an estimate of the user's preference for the languages		represents an estimate of the user's preference for the languages
	specified by that range. The quality value defaults to "q=1". For		specified by that range. The quality value defaults to "q=1". For
	example,		example,
	skipping to change at page 20, line 49		skipping to change at page 21, line 31
	the field that matches the language-tag. If no language-range in the		the field that matches the language-tag. If no language-range in the
	field matches the tag, the language quality factor assigned is 0. If		field matches the tag, the language quality factor assigned is 0. If
	no Accept-Language header is present in the request, the server		no Accept-Language header is present in the request, the server
	SHOULD assume that all languages are equally acceptable. If an		SHOULD assume that all languages are equally acceptable. If an
	Accept-Language header is present, then all languages which are		Accept-Language header is present, then all languages which are
	assigned a quality factor greater than 0 are acceptable.		assigned a quality factor greater than 0 are acceptable.
	It might be contrary to the privacy expectations of the user to send		It might be contrary to the privacy expectations of the user to send
	an Accept-Language header with the complete linguistic preferences of		an Accept-Language header with the complete linguistic preferences of
	the user in every request. For a discussion of this issue, see		the user in every request. For a discussion of this issue, see
	Section 7.1.		Section 8.1.
	As intelligibility is highly dependent on the individual user, it is		As intelligibility is highly dependent on the individual user, it is
	recommended that client applications make the choice of linguistic		recommended that client applications make the choice of linguistic
	preference available to the user. If the choice is not made		preference available to the user. If the choice is not made
	available, then the Accept-Language header field MUST NOT be given in		available, then the Accept-Language header field MUST NOT be given in
	the request.		the request.
	Note: When making the choice of linguistic preference available to		Note: When making the choice of linguistic preference available to
	the user, we remind implementors of the fact that users are not		the user, we remind implementors of the fact that users are not
	familiar with the details of language matching as described above,		familiar with the details of language matching as described above,
	and should provide appropriate guidance. As an example, users		and should provide appropriate guidance. As an example, users
	might assume that on selecting "en-gb", they will be served any		might assume that on selecting "en-gb", they will be served any
	kind of English document if British English is not available. A		kind of English document if British English is not available. A
	user agent might suggest in such a case to add "en" to get the		user agent might suggest in such a case to add "en" to get the
	best matching behavior.		best matching behavior.
	5.5. Content-Encoding		6.5. Content-Encoding
	The Content-Encoding entity-header field is used as a modifier to the		The Content-Encoding entity-header field is used as a modifier to the
	media-type. When present, its value indicates what additional		media-type. When present, its value indicates what additional
	content codings have been applied to the entity-body, and thus what		content codings have been applied to the entity-body, and thus what
	decoding mechanisms must be applied in order to obtain the media-type		decoding mechanisms must be applied in order to obtain the media-type
	referenced by the Content-Type header field. Content-Encoding is		referenced by the Content-Type header field. Content-Encoding is
	primarily used to allow a document to be compressed without losing		primarily used to allow a document to be compressed without losing
	the identity of its underlying media type.		the identity of its underlying media type.
	Content-Encoding = "Content-Encoding" ":" 1#content-coding		Content-Encoding = "Content-Encoding" ":" 1#content-coding
	Content codings are defined in Section 2.2. An example of its use is		Content codings are defined in Section 3.2. An example of its use is
	Content-Encoding: gzip		Content-Encoding: gzip
	The content-coding is a characteristic of the entity identified by		The content-coding is a characteristic of the entity identified by
	the Request-URI. Typically, the entity-body is stored with this		the Request-URI. Typically, the entity-body is stored with this
	encoding and is only decoded before rendering or analogous usage.		encoding and is only decoded before rendering or analogous usage.
	However, a non-transparent proxy MAY modify the content-coding if the		However, a non-transparent proxy MAY modify the content-coding if the
	new coding is known to be acceptable to the recipient, unless the		new coding is known to be acceptable to the recipient, unless the
	"no-transform" cache-control directive is present in the message.		"no-transform" cache-control directive is present in the message.
	If the content-coding of an entity is not "identity", then the		If the content-coding of an entity is not "identity", then the
	response MUST include a Content-Encoding entity-header (Section 5.5)		response MUST include a Content-Encoding entity-header (Section 6.5)
	that lists the non-identity content-coding(s) used.		that lists the non-identity content-coding(s) used.
	If the content-coding of an entity in a request message is not		If the content-coding of an entity in a request message is not
	acceptable to the origin server, the server SHOULD respond with a		acceptable to the origin server, the server SHOULD respond with a
	status code of 415 (Unsupported Media Type).		status code of 415 (Unsupported Media Type).
	If multiple encodings have been applied to an entity, the content		If multiple encodings have been applied to an entity, the content
	codings MUST be listed in the order in which they were applied.		codings MUST be listed in the order in which they were applied.
	Additional information about the encoding parameters MAY be provided		Additional information about the encoding parameters MAY be provided
	by other entity-header fields not defined by this specification.		by other entity-header fields not defined by this specification.
	5.6. Content-Language		6.6. Content-Language
	The Content-Language entity-header field describes the natural		The Content-Language entity-header field describes the natural
	language(s) of the intended audience for the enclosed entity. Note		language(s) of the intended audience for the enclosed entity. Note
	that this might not be equivalent to all the languages used within		that this might not be equivalent to all the languages used within
	the entity-body.		the entity-body.
	Content-Language = "Content-Language" ":" 1#language-tag		Content-Language = "Content-Language" ":" 1#language-tag
	Language tags are defined in Section 2.5. The primary purpose of		Language tags are defined in Section 3.5. The primary purpose of
	Content-Language is to allow a user to identify and differentiate		Content-Language is to allow a user to identify and differentiate
	entities according to the user's own preferred language. Thus, if		entities according to the user's own preferred language. Thus, if
	the body content is intended only for a Danish-literate audience, the		the body content is intended only for a Danish-literate audience, the
	appropriate field is		appropriate field is
	Content-Language: da		Content-Language: da
	If no Content-Language is specified, the default is that the content		If no Content-Language is specified, the default is that the content
	is intended for all language audiences. This might mean that the		is intended for all language audiences. This might mean that the
	sender does not consider it to be specific to any natural language,		sender does not consider it to be specific to any natural language,
	skipping to change at page 22, line 44		skipping to change at page 23, line 31
	However, just because multiple languages are present within an entity		However, just because multiple languages are present within an entity
	does not mean that it is intended for multiple linguistic audiences.		does not mean that it is intended for multiple linguistic audiences.
	An example would be a beginner's language primer, such as "A First		An example would be a beginner's language primer, such as "A First
	Lesson in Latin," which is clearly intended to be used by an English-		Lesson in Latin," which is clearly intended to be used by an English-
	literate audience. In this case, the Content-Language would properly		literate audience. In this case, the Content-Language would properly
	only include "en".		only include "en".
	Content-Language MAY be applied to any media type -- it is not		Content-Language MAY be applied to any media type -- it is not
	limited to textual documents.		limited to textual documents.
	5.7. Content-Location		6.7. Content-Location
	The Content-Location entity-header field MAY be used to supply the		The Content-Location entity-header field MAY be used to supply the
	resource location for the entity enclosed in the message when that		resource location for the entity enclosed in the message when that
	entity is accessible from a location separate from the requested		entity is accessible from a location separate from the requested
	resource's URI. A server SHOULD provide a Content-Location for the		resource's URI. A server SHOULD provide a Content-Location for the
	variant corresponding to the response entity; especially in the case		variant corresponding to the response entity; especially in the case
	where a resource has multiple entities associated with it, and those		where a resource has multiple entities associated with it, and those
	entities actually have separate locations by which they might be		entities actually have separate locations by which they might be
	individually accessed, the server SHOULD provide a Content-Location		individually accessed, the server SHOULD provide a Content-Location
	for the particular variant which is returned.		for the particular variant which is returned.
	skipping to change at page 23, line 16		skipping to change at page 24, line 4
	Content-Location = "Content-Location" ":"		Content-Location = "Content-Location" ":"
	( absoluteURI | relativeURI )		( absoluteURI | relativeURI )
	The value of Content-Location also defines the base URI for the		The value of Content-Location also defines the base URI for the
	entity.		entity.
	The Content-Location value is not a replacement for the original		The Content-Location value is not a replacement for the original
	requested URI; it is only a statement of the location of the resource		requested URI; it is only a statement of the location of the resource
	corresponding to this particular entity at the time of the request.		corresponding to this particular entity at the time of the request.
	Future requests MAY specify the Content-Location URI as the request-		Future requests MAY specify the Content-Location URI as the request-
	URI if the desire is to identify the source of that particular		URI if the desire is to identify the source of that particular
	entity.		entity.
	A cache cannot assume that an entity with a Content-Location		A cache cannot assume that an entity with a Content-Location
	different from the URI used to retrieve it can be used to respond to		different from the URI used to retrieve it can be used to respond to
	later requests on that Content-Location URI. However, the Content-		later requests on that Content-Location URI. However, the Content-
	Location can be used to differentiate between multiple entities		Location can be used to differentiate between multiple entities
	retrieved from a single requested resource, as described in Section 7		retrieved from a single requested resource, as described in Section 8
	of [Part6].		of [Part6].
	If the Content-Location is a relative URI, the relative URI is		If the Content-Location is a relative URI, the relative URI is
	interpreted relative to the Request-URI.		interpreted relative to the Request-URI.
	The meaning of the Content-Location header in PUT or POST requests is		The meaning of the Content-Location header in PUT or POST requests is
	undefined; servers are free to ignore it in those cases.		undefined; servers are free to ignore it in those cases.
	5.8. Content-MD5		6.8. Content-MD5
	The Content-MD5 entity-header field, as defined in [RFC1864], is an		The Content-MD5 entity-header field, as defined in [RFC1864], is an
	MD5 digest of the entity-body for the purpose of providing an end-to-		MD5 digest of the entity-body for the purpose of providing an end-to-
	end message integrity check (MIC) of the entity-body. (Note: a MIC		end message integrity check (MIC) of the entity-body. (Note: a MIC
	is good for detecting accidental modification of the entity-body in		is good for detecting accidental modification of the entity-body in
	transit, but is not proof against malicious attacks.)		transit, but is not proof against malicious attacks.)
	Content-MD5 = "Content-MD5" ":" md5-digest		Content-MD5 = "Content-MD5" ":" md5-digest
	md5-digest = <base64 of 128 bit MD5 digest as per [RFC1864]>		md5-digest = <base64 of 128 bit MD5 digest as per [RFC1864]>
	skipping to change at page 24, line 47		skipping to change at page 25, line 34
	in which the application of Content-MD5 to HTTP entity-bodies		in which the application of Content-MD5 to HTTP entity-bodies
	differs from its application to MIME entity-bodies. One is that		differs from its application to MIME entity-bodies. One is that
	HTTP, unlike MIME, does not use Content-Transfer-Encoding, and		HTTP, unlike MIME, does not use Content-Transfer-Encoding, and
	does use Transfer-Encoding and Content-Encoding. Another is that		does use Transfer-Encoding and Content-Encoding. Another is that
	HTTP more frequently uses binary content types than MIME, so it is		HTTP more frequently uses binary content types than MIME, so it is
	worth noting that, in such cases, the byte order used to compute		worth noting that, in such cases, the byte order used to compute
	the digest is the transmission byte order defined for the type.		the digest is the transmission byte order defined for the type.
	Lastly, HTTP allows transmission of text types with any of several		Lastly, HTTP allows transmission of text types with any of several
	line break conventions and not just the canonical form using CRLF.		line break conventions and not just the canonical form using CRLF.
	5.9. Content-Type		6.9. Content-Type
	The Content-Type entity-header field indicates the media type of the		The Content-Type entity-header field indicates the media type of the
	entity-body sent to the recipient or, in the case of the HEAD method,		entity-body sent to the recipient or, in the case of the HEAD method,
	the media type that would have been sent had the request been a GET.		the media type that would have been sent had the request been a GET.
	Content-Type = "Content-Type" ":" media-type		Content-Type = "Content-Type" ":" media-type
	Media types are defined in Section 2.3. An example of the field is		Media types are defined in Section 3.3. An example of the field is
	Content-Type: text/html; charset=ISO-8859-4		Content-Type: text/html; charset=ISO-8859-4
	Further discussion of methods for identifying the media type of an		Further discussion of methods for identifying the media type of an
	entity is provided in Section 3.2.1.		entity is provided in Section 4.2.1.
	6. IANA Considerations		7. IANA Considerations
	TBD.		[[anchor1: TBD.]]
	7. Security Considerations		8. Security Considerations
	This section is meant to inform application developers, information		This section is meant to inform application developers, information
	providers, and users of the security limitations in HTTP/1.1 as		providers, and users of the security limitations in HTTP/1.1 as
	described by this document. The discussion does not include		described by this document. The discussion does not include
	definitive solutions to the problems revealed, though it does make		definitive solutions to the problems revealed, though it does make
	some suggestions for reducing security risks.		some suggestions for reducing security risks.
	7.1. Privacy Issues Connected to Accept Headers		8.1. Privacy Issues Connected to Accept Headers
	Accept request-headers can reveal information about the user to all		Accept request-headers can reveal information about the user to all
	servers which are accessed. The Accept-Language header in particular		servers which are accessed. The Accept-Language header in particular
	can reveal information the user would consider to be of a private		can reveal information the user would consider to be of a private
	nature, because the understanding of particular languages is often		nature, because the understanding of particular languages is often
	strongly correlated to the membership of a particular ethnic group.		strongly correlated to the membership of a particular ethnic group.
	User agents which offer the option to configure the contents of an		User agents which offer the option to configure the contents of an
	Accept-Language header to be sent in every request are strongly		Accept-Language header to be sent in every request are strongly
	encouraged to let the configuration process include a message which		encouraged to let the configuration process include a message which
	makes the user aware of the loss of privacy involved.		makes the user aware of the loss of privacy involved.
	skipping to change at page 26, line 14		skipping to change at page 27, line 5
	many users not behind a proxy, the network address of the host		many users not behind a proxy, the network address of the host
	running the user agent will also serve as a long-lived user		running the user agent will also serve as a long-lived user
	identifier. In environments where proxies are used to enhance		identifier. In environments where proxies are used to enhance
	privacy, user agents ought to be conservative in offering accept		privacy, user agents ought to be conservative in offering accept
	header configuration options to end users. As an extreme privacy		header configuration options to end users. As an extreme privacy
	measure, proxies could filter the accept headers in relayed requests.		measure, proxies could filter the accept headers in relayed requests.
	General purpose user agents which provide a high degree of header		General purpose user agents which provide a high degree of header
	configurability SHOULD warn users about the loss of privacy which can		configurability SHOULD warn users about the loss of privacy which can
	be involved.		be involved.
	7.2. Content-Disposition Issues		8.2. Content-Disposition Issues
	[RFC1806], from which the often implemented Content-Disposition (see		[RFC1806], from which the often implemented Content-Disposition (see
	Appendix B.1) header in HTTP is derived, has a number of very serious		Appendix B.1) header in HTTP is derived, has a number of very serious
	security considerations. Content-Disposition is not part of the HTTP		security considerations. Content-Disposition is not part of the HTTP
	standard, but since it is widely implemented, we are documenting its		standard, but since it is widely implemented, we are documenting its
	use and risks for implementors. See [RFC2183] (which updates		use and risks for implementors. See [RFC2183] (which updates
	[RFC1806]) for details.		[RFC1806]) for details.
	8. Acknowledgments		9. Acknowledgments
	9. References		10. References
	9.1. Normative References		10.1. Normative References
	[ISO-8859-1]		[ISO-8859-1]
	International Organization for Standardization,		International Organization for Standardization,
	"Information technology -- 8-bit single-byte coded graphic		"Information technology -- 8-bit single-byte coded graphic
	character sets -- Part 1: Latin alphabet No. 1", ISO/		character sets -- Part 1: Latin alphabet No. 1", ISO/
	IEC 8859-1:1998, 1998.		IEC 8859-1:1998, 1998.
	[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part1] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections,		and J. Reschke, Ed., "HTTP/1.1, part 1: URIs, Connections,
	and Message Parsing", draft-ietf-httpbis-p1-messaging-01		and Message Parsing", draft-ietf-httpbis-p1-messaging-02
	(work in progress), January 2008.		(work in progress), February 2008.
	[Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part2] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 2: Message		and J. Reschke, Ed., "HTTP/1.1, part 2: Message
	Semantics", draft-ietf-httpbis-p2-semantics-01 (work in		Semantics", draft-ietf-httpbis-p2-semantics-02 (work in
	progress), January 2008.		progress), February 2008.
	[Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part4] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional		and J. Reschke, Ed., "HTTP/1.1, part 4: Conditional
	Requests", draft-ietf-httpbis-p4-conditional-01 (work in		Requests", draft-ietf-httpbis-p4-conditional-02 (work in
	progress), January 2008.		progress), February 2008.
	[Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part5] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and		and J. Reschke, Ed., "HTTP/1.1, part 5: Range Requests and
	Partial Responses", draft-ietf-httpbis-p5-range-01 (work		Partial Responses", draft-ietf-httpbis-p5-range-02 (work
	in progress), January 2008.		in progress), February 2008.
	[Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,		[Part6] Fielding, R., Ed., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,		Masinter, L., Leach, P., Berners-Lee, T., Lafon, Y., Ed.,
	and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",		and J. Reschke, Ed., "HTTP/1.1, part 6: Caching",
	draft-ietf-httpbis-p6-cache-01 (work in progress),		draft-ietf-httpbis-p6-cache-02 (work in progress),
	January 2008.		February 2008.
	[RFC1766] Alvestrand, H., "Tags for the Identification of		[RFC1766] Alvestrand, H., "Tags for the Identification of
	Languages", RFC 1766, March 1995.		Languages", RFC 1766, March 1995.
	[RFC1864] Myers, J. and M. Rose, "The Content-MD5 Header Field",		[RFC1864] Myers, J. and M. Rose, "The Content-MD5 Header Field",
	RFC 1864, October 1995.		RFC 1864, October 1995.
	[RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format		[RFC1950] Deutsch, L. and J-L. Gailly, "ZLIB Compressed Data Format
	Specification version 3.3", RFC 1950, May 1996.		Specification version 3.3", RFC 1950, May 1996.
	skipping to change at page 28, line 16		skipping to change at page 29, line 6
	Extensions (MIME) Part One: Format of Internet Message		Extensions (MIME) Part One: Format of Internet Message
	Bodies", RFC 2045, November 1996.		Bodies", RFC 2045, November 1996.
	[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.
	[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and		10.2. Informative References
	Registration Procedures", BCP 13, RFC 4288, December 2005.
	9.2. Informative References
	[RFC1806] Troost, R. and S. Dorner, "Communicating Presentation		[RFC1806] Troost, R. and S. Dorner, "Communicating Presentation
	Information in Internet Messages: The Content-Disposition		Information in Internet Messages: The Content-Disposition
	Header", RFC 1806, June 1995.		Header", RFC 1806, June 1995.
	[RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext		[RFC1945] Berners-Lee, T., Fielding, R., and H. Nielsen, "Hypertext
	Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996.		Transfer Protocol -- HTTP/1.0", RFC 1945, May 1996.
	[RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail		[RFC2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
	Extensions (MIME) Part Five: Conformance Criteria and		Extensions (MIME) Part Five: Conformance Criteria and
	skipping to change at page 29, line 15		skipping to change at page 29, line 50
	[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,		[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
	Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext		Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
	Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.		Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
	[RFC2822] Resnick, P., "Internet Message Format", RFC 2822,		[RFC2822] Resnick, P., "Internet Message Format", RFC 2822,
	April 2001.		April 2001.
	[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO		[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
	10646", RFC 3629, STD 63, November 2003.		10646", RFC 3629, STD 63, November 2003.
			[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and
			Registration Procedures", BCP 13, RFC 4288, December 2005.
	Appendix A. Differences Between HTTP Entities and RFC 2045 Entities		Appendix A. Differences Between HTTP Entities and RFC 2045 Entities
	HTTP/1.1 uses many of the constructs defined for Internet Mail		HTTP/1.1 uses many of the constructs defined for Internet Mail
	([RFC2822]) and the Multipurpose Internet Mail Extensions (MIME		([RFC2822]) and the Multipurpose Internet Mail Extensions (MIME
	[RFC2045]) to allow entities to be transmitted in an open variety of		[RFC2045]) to allow entities to be transmitted in an open variety of
	representations and with extensible mechanisms. However, RFC 2045		representations and with extensible mechanisms. However, RFC 2045
	discusses mail, and HTTP has a few features that are different from		discusses mail, and HTTP has a few features that are different from
	those described in RFC 2045. These differences were carefully chosen		those described in RFC 2045. These differences were carefully chosen
	to optimize performance over binary connections, to allow greater		to optimize performance over binary connections, to allow greater
	freedom in the use of new media types, to make date comparisons		freedom in the use of new media types, to make date comparisons
	skipping to change at page 30, line 9		skipping to change at page 30, line 45
	MIME-Version = "MIME-Version" ":" 1*DIGIT "." 1*DIGIT		MIME-Version = "MIME-Version" ":" 1*DIGIT "." 1*DIGIT
	MIME version "1.0" is the default for use in HTTP/1.1. However,		MIME version "1.0" is the default for use in HTTP/1.1. However,
	HTTP/1.1 message parsing and semantics are defined by this document		HTTP/1.1 message parsing and semantics are defined by this document
	and not the MIME specification.		and not the MIME specification.
	A.2. Conversion to Canonical Form		A.2. Conversion to Canonical Form
	[RFC2045] requires that an Internet mail entity be converted to		[RFC2045] requires that an Internet mail entity be converted to
	canonical form prior to being transferred, as described in Section 4		canonical form prior to being transferred, as described in Section 4
	of [RFC2049]. Section 2.3.1 of this document describes the forms		of [RFC2049]. Section 3.3.1 of this document describes the forms
	allowed for subtypes of the "text" media type when transmitted over		allowed for subtypes of the "text" media type when transmitted over
	HTTP. [RFC2046] requires that content with a type of "text"		HTTP. [RFC2046] requires that content with a type of "text"
	represent line breaks as CRLF and forbids the use of CR or LF outside		represent line breaks as CRLF and forbids the use of CR or LF outside
	of line break sequences. HTTP allows CRLF, bare CR, and bare LF to		of line break sequences. HTTP allows CRLF, bare CR, and bare LF to
	indicate a line break within text content when a message is		indicate a line break within text content when a message is
	transmitted over HTTP.		transmitted over HTTP.
	Where it is possible, a proxy or gateway from HTTP to a strict MIME		Where it is possible, a proxy or gateway from HTTP to a strict MIME
	environment SHOULD translate all line breaks within the text media		environment SHOULD translate all line breaks within the text media
	types described in Section 2.3.1 of this document to the RFC 2049		types described in Section 3.3.1 of this document to the RFC 2049
	canonical form of CRLF. Note, however, that this might be		canonical form of CRLF. Note, however, that this might be
	complicated by the presence of a Content-Encoding and by the fact		complicated by the presence of a Content-Encoding and by the fact
	that HTTP allows the use of some character sets which do not use		that HTTP allows the use of some character sets which do not use
	octets 13 and 10 to represent CR and LF, as is the case for some		octets 13 and 10 to represent CR and LF, as is the case for some
	multi-byte character sets.		multi-byte character sets.
	Implementors should note that conversion will break any cryptographic		Implementors should note that conversion will break any cryptographic
	checksums applied to the original content unless the original content		checksums applied to the original content unless the original content
	is already in canonical form. Therefore, the canonical form is		is already in canonical form. Therefore, the canonical form is
	recommended for any content that uses such checksums in HTTP.		recommended for any content that uses such checksums in HTTP.
	skipping to change at page 31, line 23		skipping to change at page 32, line 13
	to forwarding a message via a MIME-compliant protocol.		to forwarding a message via a MIME-compliant protocol.
	A.6. MHTML and Line Length Limitations		A.6. MHTML and Line Length Limitations
	HTTP implementations which share code with MHTML [RFC2557]		HTTP implementations which share code with MHTML [RFC2557]
	implementations need to be aware of MIME line length limitations.		implementations need to be aware of MIME line length limitations.
	Since HTTP does not have this limitation, HTTP does not fold long		Since HTTP does not have this limitation, HTTP does not fold long
	lines. MHTML messages being transported by HTTP follow all		lines. MHTML messages being transported by HTTP follow all
	conventions of MHTML, including line length limitations and folding,		conventions of MHTML, including line length limitations and folding,
	canonicalization, etc., since HTTP transports all message-bodies as		canonicalization, etc., since HTTP transports all message-bodies as
	payload (see Section 2.3.2) and does not interpret the content or any		payload (see Section 3.3.2) and does not interpret the content or any
	MIME header lines that might be contained therein.		MIME header lines that might be contained therein.
	Appendix B. Additional Features		Appendix B. Additional Features
	[RFC1945] and [RFC2068] document protocol elements used by some		[RFC1945] and [RFC2068] document protocol elements used by some
	existing HTTP implementations, but not consistently and correctly		existing HTTP implementations, but not consistently and correctly
	across most HTTP/1.1 applications. Implementors are advised to be		across most HTTP/1.1 applications. Implementors are advised to be
	aware of these features, but cannot rely upon their presence in, or		aware of these features, but cannot rely upon their presence in, or
	interoperability with, other HTTP/1.1 applications. Some of these		interoperability with, other HTTP/1.1 applications. Some of these
	describe proposed experimental features, and some describe features		describe proposed experimental features, and some describe features
	skipping to change at page 32, line 20		skipping to change at page 33, line 4
	disp-extension-token = token		disp-extension-token = token
	disp-extension-parm = token "=" ( token | quoted-string )		disp-extension-parm = token "=" ( token | quoted-string )
	An example is		An example is
	Content-Disposition: attachment; filename="fname.ext"		Content-Disposition: attachment; filename="fname.ext"
	The receiving user agent SHOULD NOT respect any directory path		The receiving user agent SHOULD NOT respect any directory path
	information present in the filename-parm parameter, which is the only		information present in the filename-parm parameter, which is the only
	parameter believed to apply to HTTP implementations at this time.		parameter believed to apply to HTTP implementations at this time.
	The filename SHOULD be treated as a terminal component only.		The filename SHOULD be treated as a terminal component only.
	If this header is used in a response with the application/		If this header is used in a response with the application/
	octet-stream content-type, the implied suggestion is that the user		octet-stream content-type, the implied suggestion is that the user
	agent should not display the response, but directly enter a `save		agent should not display the response, but directly enter a `save
	response as...' dialog.		response as...' dialog.
	See Section 7.2 for Content-Disposition security issues.		See Section 8.2 for Content-Disposition security issues.
	Appendix C. Compatibility with Previous Versions		Appendix C. Compatibility with Previous Versions
	C.1. Changes from RFC 2068		C.1. Changes from RFC 2068
	Transfer-coding and message lengths all interact in ways that		Transfer-coding and message lengths all interact in ways that
	required fixing exactly when chunked encoding is used (to allow for		required fixing exactly when chunked encoding is used (to allow for
	transfer encoding that may not be self delimiting); it was important		transfer encoding that may not be self delimiting); it was important
	to straighten out exactly how message lengths are computed.		to straighten out exactly how message lengths are computed.
	(Section 3.2.2, see also [Part1], [Part5] and [Part6]).		(Section 4.2.2, see also [Part1], [Part5] and [Part6]).
	Charset wildcarding is introduced to avoid explosion of character set		Charset wildcarding is introduced to avoid explosion of character set
	names in accept headers. (Section 5.2)		names in accept headers. (Section 6.2)
	Content-Base was deleted from the specification: it was not		Content-Base was deleted from the specification: it was not
	implemented widely, and there is no simple, safe way to introduce it		implemented widely, and there is no simple, safe way to introduce it
	without a robust extension mechanism. In addition, it is used in a		without a robust extension mechanism. In addition, it is used in a
	similar, but not identical fashion in MHTML [RFC2557].		similar, but not identical fashion in MHTML [RFC2557].
	A content-coding of "identity" was introduced, to solve problems		A content-coding of "identity" was introduced, to solve problems
	discovered in caching. (Section 2.2)		discovered in caching. (Section 3.2)
	Quality Values of zero should indicate that "I don't want something"		Quality Values of zero should indicate that "I don't want something"
	to allow clients to refuse a representation. (Section 2.4)		to allow clients to refuse a representation. (Section 3.4)
	The Alternates, Content-Version, Derived-From, Link, URI, Public and		The Alternates, Content-Version, Derived-From, Link, URI, Public and
	Content-Base header fields were defined in previous versions of this		Content-Base header fields were defined in previous versions of this
	specification, but not commonly implemented. See [RFC2068].		specification, but not commonly implemented. See [RFC2068].
	C.2. Changes from RFC 2616		C.2. Changes from RFC 2616
	Clarify contexts that charset is used in. (Section 2.1)		Clarify contexts that charset is used in. (Section 3.1)
	Remove reference to non-existant identity transfer-coding value		Remove reference to non-existant identity transfer-coding value
	tokens. (Appendix A.4)		tokens. (Appendix A.4)
	Appendix D. Change Log (to be removed by RFC Editor before publication)		Appendix D. Change Log (to be removed by RFC Editor before publication)
	D.1. Since RFC2616		D.1. Since RFC2616
	Extracted relevant partitions from [RFC2616].		Extracted relevant partitions from [RFC2616].
	skipping to change at page 33, line 45		skipping to change at page 34, line 35
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/25>: "Accept-		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/25>: "Accept-
	Encoding BNF"		Encoding BNF"
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35>: "Normative		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35>: "Normative
	and Informative references"		and Informative references"
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/46>: "RFC1700		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/46>: "RFC1700
	references"		references"
			o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/55>: "Updating
			to RFC4288"
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/65>:		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/65>:
	"Informative references"		"Informative references"
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/66>:		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/66>:
	"ISO-8859-1 Reference"		"ISO-8859-1 Reference"
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/68>: "Encoding		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/68>: "Encoding
	References Normative"		References Normative"
	o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86>: "Normative		o <http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86>: "Normative
	up-to-date references"		up-to-date references"
			D.3. Since draft-ietf-httpbis-p3-payload-01
			Ongoing work on ABNF conversion
			(<http://www3.tools.ietf.org/wg/httpbis/trac/ticket/36>):
			o Add explicit references to BNF syntax and rules imported from
			other parts of the specification.
	Index		Index
	A		A
	Accept header 16		Accept header 16
	Accept-Charset header 18		Accept-Charset header 18
	Accept-Encoding header 18		Accept-Encoding header 19
	Accept-Language header 20		Accept-Language header 20
	Alternates header 33		Alternates header 33
	C		C
	compress 7		compress 8
	Content-Base header 33		Content-Base header 33
	Content-Disposition header 31		Content-Disposition header 32
	Content-Encoding header 21		Content-Encoding header 22
	Content-Language header 22		Content-Language header 22
	Content-Location header 22		Content-Location header 23
	Content-MD5 header 23		Content-MD5 header 24
	Content-Type header 24		Content-Type header 25
	Content-Version header 33		Content-Version header 33
	D		D
	deflate 7		deflate 8
	Derived-From header 33		Derived-From header 33
	G		G
	Grammar		Grammar
	Accept 16		Accept 16
	Accept-Charset 18		Accept-Charset 18
	Accept-Encoding 18		Accept-Encoding 19
	accept-extension 16		accept-extension 16
	Accept-Language 20		Accept-Language 20
	accept-params 16		accept-params 16
	attribute 8		attribute 9
	charset 6		charset 7
	codings 18		codings 19
	content-coding 7		content-coding 7
	content-disposition 32		content-disposition 32
	Content-Encoding 21		Content-Encoding 22
	Content-Language 22		Content-Language 22
	Content-Location 23		Content-Location 23
	Content-MD5 23		Content-MD5 24
	Content-Type 24		Content-Type 25
	disp-extension-parm 32		disp-extension-parm 32
	disp-extension-token 32		disp-extension-token 32
	disposition-parm 32		disposition-parm 32
	disposition-type 32		disposition-type 32
	entity-body 12		entity-body 12
	entity-header 11		entity-header 12
	extension-header 11		extension-header 12
	filename-parm 32		filename-parm 32
	language-range 20		language-range 20
	language-tag 11		language-tag 11
	md5-digest 23		md5-digest 24
	media-range 16		media-range 16
	media-type 8		media-type 9
	MIME-Version 29		MIME-Version 30
	parameter 8		parameter 9
	primary-tag 11		primary-tag 11
	qvalue 10		qvalue 11
	subtag 11		subtag 11
	subtype 8		subtype 9
	type 8		type 9
	value 8		value 9
	gzip 7		gzip 8
	H		H
	Headers		Headers
	Accept 16		Accept 16
	Accept-Charset 18		Accept-Charset 18
	Accept-Encoding 18		Accept-Encoding 19
	Accept-Language 20		Accept-Language 20
	Alternate 33		Alternate 33
	Content-Base 33		Content-Base 33
	Content-Disposition 31		Content-Disposition 32
	Content-Encoding 21		Content-Encoding 22
	Content-Language 22		Content-Language 22
	Content-Location 22		Content-Location 23
	Content-MD5 23		Content-MD5 24
	Content-Type 24		Content-Type 25
	Content-Version 33		Content-Version 33
	Derived-From 33		Derived-From 33
	Link 33		Link 33
	Public 33		Public 33
	URI 33		URI 33
	I		I
	identity 8		identity 8
	L		L
	Link header 33		Link header 33
	P		P
	Public header 33		Public header 33
	U		U
	URI header 33		URI header 33
	Authors' Addresses		Authors' Addresses
End of changes. 108 change blocks.
	180 lines changed or deleted		223 lines changed or added
This html diff was produced by rfcdiff 1.34. The latest version is available from http://tools.ietf.org/tools/rfcdiff/