Changeset 1643
- Timestamp:
- 30/03/12 15:19:59 (10 years ago)
- Location:
- draft-ietf-httpbis/latest
- Files:
-
- 12 edited
Legend:
- Unmodified
- Added
- Removed
-
draft-ietf-httpbis/latest/Makefile
r1640 r1643 15 15 p7-auth.xml 16 16 17 TARGETS_ABNF= $(TARGETS_XML:.xml=.abnf) 18 TARGETS_ABNFAPPENDIX= $(TARGETS_XML:.xml=.abnf-appendix) 17 TARGETS_ABNF= p1-messaging.abnf \ 18 p2-semantics.abnf \ 19 p4-conditional.abnf \ 20 p5-range.abnf \ 21 p6-cache.abnf \ 22 p7-auth.abnf 23 24 TARGETS_ABNFAPPENDIX= $(TARGETS_abnf:.xml=.abnf-appendix) 19 25 TARGETS_HTML= $(TARGETS_XML:.xml=.html) 20 26 TARGETS_XHTML= $(TARGETS_XML:.xml=.xhtml) 21 TARGETS_PARSEDABNF= $(TARGETS_ XML:.xml=.parsed-abnf)27 TARGETS_PARSEDABNF= $(TARGETS_ABNF:.abnf=.parsed-abnf) 22 28 TARGETS_REDXML= $(TARGETS_XML:.xml=.redxml) 23 29 TARGETS_TXT= $(TARGETS_XML:.xml=.txt) -
draft-ietf-httpbis/latest/p1-messaging.html
r1635 r1643 460 460 } 461 461 @bottom-center { 462 content: "Expires September 30, 2012";462 content: "Expires October 1, 2012"; 463 463 } 464 464 @bottom-right { … … 502 502 <meta name="dct.creator" content="Reschke, J. F."> 503 503 <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p1-messaging-latest"> 504 <meta name="dct.issued" scheme="ISO8601" content="2012-03- 29">504 <meta name="dct.issued" scheme="ISO8601" content="2012-03-30"> 505 505 <meta name="dct.replaces" content="urn:ietf:rfc:2145"> 506 506 <meta name="dct.replaces" content="urn:ietf:rfc:2616"> … … 534 534 </tr> 535 535 <tr> 536 <td class="left">Expires: September 30, 2012</td>536 <td class="left">Expires: October 1, 2012</td> 537 537 <td class="right">greenbytes</td> 538 538 </tr> 539 539 <tr> 540 540 <td class="left"></td> 541 <td class="right">March 29, 2012</td>541 <td class="right">March 30, 2012</td> 542 542 </tr> 543 543 </tbody> … … 572 572 in progress”. 573 573 </p> 574 <p>This Internet-Draft will expire on September 30, 2012.</p>574 <p>This Internet-Draft will expire on October 1, 2012.</p> 575 575 <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1> 576 576 <p>Copyright © 2012 IETF Trust and the persons identified as the document authors. All rights reserved.</p> … … 757 757 <p id="rfc.section.1.p.1">The Hypertext Transfer Protocol (HTTP) is an application-level request/response protocol that uses extensible semantics and 758 758 MIME-like message payloads for flexible interaction with network-based hypertext information systems. HTTP relies upon the 759 Uniform Resource Identifier (URI) standard <a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a> to indicate the target resource (<a href="#target-resource" title="Identifying a Target Resource">Section 5.1</a>) and relationships between resources. Messages are passed in a format similar to that used by Internet mail <a href="#RFC5322" id="rfc.xref.RFC5322.1"><cite title="Internet Message Format">[RFC5322]</cite></a> and the Multipurpose Internet Mail Extensions (MIME) <a href="#RFC2045" id="rfc.xref.RFC2045.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a> (see <a href="p 3-payload.html#differences.between.http.and.mime" title="Differences between HTTP and MIME">Appendix A</a> of <a href="#Part3" id="rfc.xref.Part3.1"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a> for the differences between HTTP and MIME messages).759 Uniform Resource Identifier (URI) standard <a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a> to indicate the target resource (<a href="#target-resource" title="Identifying a Target Resource">Section 5.1</a>) and relationships between resources. Messages are passed in a format similar to that used by Internet mail <a href="#RFC5322" id="rfc.xref.RFC5322.1"><cite title="Internet Message Format">[RFC5322]</cite></a> and the Multipurpose Internet Mail Extensions (MIME) <a href="#RFC2045" id="rfc.xref.RFC2045.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a> (see <a href="p2-semantics.html#differences.between.http.and.mime" title="Differences between HTTP and MIME">Appendix D.8</a> of <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for the differences between HTTP and MIME messages). 760 760 </p> 761 761 <p id="rfc.section.1.p.2">HTTP is a generic interface protocol for information systems. It is designed to hide the details of how a service is implemented … … 910 910 or an intranet-to-Internet privacy filter. Such transformations are presumed to be desired by the client (or client organization) 911 911 that selected the proxy and are beyond the scope of this specification. However, when a proxy is not intended to transform 912 a given message, we use the term "<dfn>non-transforming proxy</dfn>" to target requirements that preserve HTTP message semantics. See <a href="p2-semantics.html#status.203" title="203 Non-Authoritative Information">Section 4.4.4</a> of <a href="#Part2" id="rfc.xref.Part2. 1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> and <a href="p6-cache.html#header.warning" title="Warning">Section 3.6</a> of <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a> for status and warning codes related to transformations.912 a given message, we use the term "<dfn>non-transforming proxy</dfn>" to target requirements that preserve HTTP message semantics. See <a href="p2-semantics.html#status.203" title="203 Non-Authoritative Information">Section 4.4.4</a> of <a href="#Part2" id="rfc.xref.Part2.2"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> and <a href="p6-cache.html#header.warning" title="Warning">Section 3.6</a> of <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a> for status and warning codes related to transformations. 913 913 </p> 914 914 <p id="rfc.section.2.3.p.7"><span id="rfc.iref.g.13"></span><span id="rfc.iref.r.4"></span> <span id="rfc.iref.a.1"></span> A "<dfn>gateway</dfn>" (a.k.a., "<dfn>reverse proxy</dfn>") is a receiving agent that acts as a layer above some other server(s) and translates the received requests to the underlying … … 1078 1078 </p> 1079 1079 <p id="rfc.section.2.7.1.p.6">When an "http" URI is used within a context that calls for access to the indicated resource, a client <em class="bcp14">MAY</em> attempt access by resolving the host to an IP address, establishing a TCP connection to that address on the indicated port, 1080 and sending an HTTP request message (<a href="#http.message" title="Message Format">Section 3</a>) containing the URI's identifying data (<a href="#message.routing" title="Message Routing">Section 5</a>) to the server. If the server responds to that request with a non-interim HTTP response message, as described in <a href="p2-semantics.html#status.codes" title="Status Codes">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2. 2"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, then that response is considered an authoritative answer to the client's request.1080 and sending an HTTP request message (<a href="#http.message" title="Message Format">Section 3</a>) containing the URI's identifying data (<a href="#message.routing" title="Message Routing">Section 5</a>) to the server. If the server responds to that request with a non-interim HTTP response message, as described in <a href="p2-semantics.html#status.codes" title="Status Codes">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, then that response is considered an authoritative answer to the client's request. 1081 1081 </p> 1082 1082 <p id="rfc.section.2.7.1.p.7">Although HTTP is independent of the transport protocol, the "http" scheme is specific to TCP-based services because the name … … 1174 1174 </div> 1175 1175 <div id="rfc.figure.u.14"></div><pre class="inline"><span id="rfc.iref.g.28"></span> <a href="#method" class="smpl">method</a> = <a href="#rule.token.separators" class="smpl">token</a> 1176 </pre><p id="rfc.section.3.1.1.p.5">The methods defined by this specification can be found in <a href="p2-semantics.html#methods" title="Methods">Section 2</a> of <a href="#Part2" id="rfc.xref.Part2. 3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, along with information regarding the HTTP method registry and considerations for defining new methods.1176 </pre><p id="rfc.section.3.1.1.p.5">The methods defined by this specification can be found in <a href="p2-semantics.html#methods" title="Methods">Section 2</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, along with information regarding the HTTP method registry and considerations for defining new methods. 1177 1177 </p> 1178 1178 <div id="rfc.iref.r.6"></div> … … 1189 1189 <p id="rfc.section.3.1.1.p.9">HTTP does not place a pre-defined limit on the length of a request-line. A server that receives a method longer than any that 1190 1190 it implements <em class="bcp14">SHOULD</em> respond with either a 405 (Not Allowed), if it is an origin server, or a 501 (Not Implemented) status code. A server <em class="bcp14">MUST</em> be prepared to receive URIs of unbounded length and respond with the 414 (URI Too Long) status code if the received request-target 1191 would be longer than the server wishes to handle (see <a href="p2-semantics.html#status.414" title="414 URI Too Long">Section 4.6.12</a> of <a href="#Part2" id="rfc.xref.Part2. 4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).1191 would be longer than the server wishes to handle (see <a href="p2-semantics.html#status.414" title="414 URI Too Long">Section 4.6.12</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). 1192 1192 </p> 1193 1193 <p id="rfc.section.3.1.1.p.10">Various ad-hoc limitations on request-line length are found in practice. It is <em class="bcp14">RECOMMENDED</em> that all HTTP senders and recipients support, at a minimum, request-line lengths of up to 8000 octets. … … 1199 1199 <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.29"></span> <a href="#status.line" class="smpl">status-line</a> = <a href="#http.version" class="smpl">HTTP-version</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status-code" class="smpl">status-code</a> <a href="#core.rules" class="smpl">SP</a> <a href="#reason-phrase" class="smpl">reason-phrase</a> <a href="#core.rules" class="smpl">CRLF</a> 1200 1200 </pre><div id="status-code"> 1201 <p id="rfc.section.3.1.2.p.3">The status-code element is a 3-digit integer result code of the attempt to understand and satisfy the request. See <a href="p2-semantics.html#status.codes" title="Status Codes">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2. 5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for further information, such as the list of status codes defined by this specification, the IANA registry, and considerations1201 <p id="rfc.section.3.1.2.p.3">The status-code element is a 3-digit integer result code of the attempt to understand and satisfy the request. See <a href="p2-semantics.html#status.codes" title="Status Codes">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.6"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for further information, such as the list of status codes defined by this specification, the IANA registry, and considerations 1202 1202 for new status codes. 1203 1203 </p> … … 1223 1223 ; see <a href="#field.parsing" title="Field Parsing">Section 3.2.2</a> 1224 1224 </pre><p id="rfc.section.3.2.p.3">The field-name token labels the corresponding field-value as having the semantics defined by that header field. For example, 1225 the Date header field is defined in <a href="p2-semantics.html#header.date" title="Date">Section 7.2</a> of <a href="#Part2" id="rfc.xref.Part2. 6"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> as containing the origination timestamp for the message in which it appears.1225 the Date header field is defined in <a href="p2-semantics.html#header.date" title="Date">Section 7.2</a> of <a href="#Part2" id="rfc.xref.Part2.7"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> as containing the origination timestamp for the message in which it appears. 1226 1226 </p> 1227 1227 <p id="rfc.section.3.2.p.4">HTTP header fields are fully extensible: there is no limit on the introduction of new field names, each presumably defining … … 1231 1231 them. 1232 1232 </p> 1233 <p id="rfc.section.3.2.p.5">New HTTP header fields <em class="bcp14">SHOULD</em> be registered with IANA according to the procedures in <a href="p2-semantics.html#considerations.for.creating.header.fields" title="Considerations for Creating Header Fields">Section 3.1</a> of <a href="#Part2" id="rfc.xref.Part2. 7"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>. Unrecognized header fields <em class="bcp14">MUST</em> be forwarded by a proxy unless the field-name is listed in the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.3" title="Connection">Section 6.1</a>) or the proxy is specifically configured to block or otherwise transform such fields. Unrecognized header fields <em class="bcp14">SHOULD</em> be ignored by other recipients.1233 <p id="rfc.section.3.2.p.5">New HTTP header fields <em class="bcp14">SHOULD</em> be registered with IANA according to the procedures in <a href="p2-semantics.html#considerations.for.creating.header.fields" title="Considerations for Creating Header Fields">Section 3.1</a> of <a href="#Part2" id="rfc.xref.Part2.8"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>. Unrecognized header fields <em class="bcp14">MUST</em> be forwarded by a proxy unless the field-name is listed in the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.3" title="Connection">Section 6.1</a>) or the proxy is specifically configured to block or otherwise transform such fields. Unrecognized header fields <em class="bcp14">SHOULD</em> be ignored by other recipients. 1234 1234 </p> 1235 1235 <p id="rfc.section.3.2.p.6">The order in which header fields with differing field names are received is not significant. However, it is "good practice" … … 1418 1418 <p id="rfc.section.3.3.1.p.6">If more than one Transfer-Encoding header field is present in a message, the multiple field-values <em class="bcp14">MUST</em> be combined into one field-value, according to the algorithm defined in <a href="#header.fields" title="Header Fields">Section 3.2</a>, before determining the message body length. 1419 1419 </p> 1420 <p id="rfc.section.3.3.1.p.7">Unlike Content-Encoding (<a href="p 3-payload.html#content.codings" title="Content Codings">Section 2.2</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>), Transfer-Encoding is a property of the message, not of the payload, and thus <em class="bcp14">MAY</em> be added or removed by any implementation along the request/response chain. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other header fields not defined by this specification.1420 <p id="rfc.section.3.3.1.p.7">Unlike Content-Encoding (<a href="p2-semantics.html#content.codings" title="Content Codings">Appendix D.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.9"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), Transfer-Encoding is a property of the message, not of the payload, and thus <em class="bcp14">MAY</em> be added or removed by any implementation along the request/response chain. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other header fields not defined by this specification. 1421 1421 </p> 1422 1422 <p id="rfc.section.3.3.1.p.8">Transfer-Encoding <em class="bcp14">MAY</em> be sent in a response to a HEAD request or in a 304 response to a GET request, neither of which includes a message body, to … … 1725 1725 </p> 1726 1726 <h3 id="rfc.section.4.3.1"><a href="#rfc.section.4.3.1">4.3.1</a> <a id="quality.values" href="#quality.values">Quality Values</a></h3> 1727 <p id="rfc.section.4.3.1.p.1">Both transfer codings (TE request header field, <a href="#header.te" id="rfc.xref.header.te.3" title="TE">Section 4.3</a>) and content negotiation (<a href="p 3-payload.html#content.negotiation" title="Content Negotiation">Section 5</a> of <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) use short "floating point" numbers to indicate the relative importance ("weight") of various negotiable parameters. A weight1727 <p id="rfc.section.4.3.1.p.1">Both transfer codings (TE request header field, <a href="#header.te" id="rfc.xref.header.te.3" title="TE">Section 4.3</a>) and content negotiation (<a href="p2-semantics.html#content.negotiation" title="Content Negotiation">Appendix D.4</a> of <a href="#Part2" id="rfc.xref.Part2.10"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) use short "floating point" numbers to indicate the relative importance ("weight") of various negotiable parameters. A weight 1728 1728 is normalized to a real number in the range 0 through 1, where 0 is the minimum and 1 the maximum value. If a parameter has 1729 1729 a quality value of 0, then content with this parameter is "not acceptable" for the client. HTTP/1.1 applications <em class="bcp14">MUST NOT</em> generate more than three digits after the decimal point. User configuration of these values <em class="bcp14">SHOULD</em> also be limited in this fashion. … … 1767 1767 </p> 1768 1768 <p id="rfc.section.5.1.p.2">HTTP communication is initiated by a user agent for some purpose. The purpose is a combination of request semantics, which 1769 are defined in <a href="#Part2" id="rfc.xref.Part2. 8"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, and a target resource upon which to apply those semantics. A URI reference (<a href="#uri" title="Uniform Resource Identifiers">Section 2.7</a>) is typically used as an identifier for the "target resource", which a user agent would resolve to its absolute form in order1769 are defined in <a href="#Part2" id="rfc.xref.Part2.11"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, and a target resource upon which to apply those semantics. A URI reference (<a href="#uri" title="Uniform Resource Identifiers">Section 2.7</a>) is typically used as an identifier for the "target resource", which a user agent would resolve to its absolute form in order 1770 1770 to obtain the "target URI". The target URI excludes the reference's fragment identifier component, if any, since fragment 1771 1771 identifiers are reserved for client-side processing (<a href="#RFC3986" id="rfc.xref.RFC3986.18"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-3.5">Section 3.5</a>). … … 1826 1826 </p> 1827 1827 <div id="authority-form"> 1828 <p id="rfc.section.5.3.p.13"><span id="rfc.iref.a.3"></span> The authority-form of request-target is only used for CONNECT requests (<a href="p2-semantics.html#CONNECT" title="CONNECT">Section 2.3.8</a> of <a href="#Part2" id="rfc.xref.Part2. 9"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). When making a CONNECT request to establish a tunnel through one or more proxies, a client <em class="bcp14">MUST</em> send only the target URI's authority component (excluding any userinfo) as the request-target. For example,1828 <p id="rfc.section.5.3.p.13"><span id="rfc.iref.a.3"></span> The authority-form of request-target is only used for CONNECT requests (<a href="p2-semantics.html#CONNECT" title="CONNECT">Section 2.3.8</a> of <a href="#Part2" id="rfc.xref.Part2.12"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). When making a CONNECT request to establish a tunnel through one or more proxies, a client <em class="bcp14">MUST</em> send only the target URI's authority component (excluding any userinfo) as the request-target. For example, 1829 1829 </p> 1830 1830 </div> 1831 1831 <div id="rfc.figure.u.49"></div><pre class="text2">CONNECT www.example.com:80 HTTP/1.1 1832 1832 </pre><div id="asterisk-form"> 1833 <p id="rfc.section.5.3.p.15"><span id="rfc.iref.a.4"></span> The asterisk-form of request-target is only used for a server-wide OPTIONS request (<a href="p2-semantics.html#OPTIONS" title="OPTIONS">Section 2.3.1</a> of <a href="#Part2" id="rfc.xref.Part2.1 0"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). When a client wishes to request OPTIONS for the server as a whole, as opposed to a specific named resource of that server,1833 <p id="rfc.section.5.3.p.15"><span id="rfc.iref.a.4"></span> The asterisk-form of request-target is only used for a server-wide OPTIONS request (<a href="p2-semantics.html#OPTIONS" title="OPTIONS">Section 2.3.1</a> of <a href="#Part2" id="rfc.xref.Part2.13"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). When a client wishes to request OPTIONS for the server as a whole, as opposed to a specific named resource of that server, 1834 1834 the client <em class="bcp14">MUST</em> send only "*" (%x2A) as the request-target. For example, 1835 1835 </p> … … 1986 1986 </p> 1987 1987 </div> 1988 <p id="rfc.section.5.6.2.p.8">A non-transforming proxy <em class="bcp14">MUST</em> preserve the message payload (<a href="#Part 3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>), though it <em class="bcp14">MAY</em> change the message body through application or removal of a transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section 4</a>).1988 <p id="rfc.section.5.6.2.p.8">A non-transforming proxy <em class="bcp14">MUST</em> preserve the message payload (<a href="#Part2" id="rfc.xref.Part2.14"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), though it <em class="bcp14">MAY</em> change the message body through application or removal of a transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section 4</a>). 1989 1989 </p> 1990 1990 <h2 id="rfc.section.5.7"><a href="#rfc.section.5.7">5.7</a> <a id="associating.response.to.request" href="#associating.response.to.request">Associating a Response to a Request</a></h2> … … 1992 1992 messages. Hence, it relies on the order of response arrival to correspond exactly to the order in which requests are made 1993 1993 on the same connection. More than one response message per request only occurs when one or more informational responses (1xx, 1994 see <a href="p2-semantics.html#status.1xx" title="Informational 1xx">Section 4.3</a> of <a href="#Part2" id="rfc.xref.Part2.1 1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) precede a final response to the same request.1994 see <a href="p2-semantics.html#status.1xx" title="Informational 1xx">Section 4.3</a> of <a href="#Part2" id="rfc.xref.Part2.15"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) precede a final response to the same request. 1995 1995 </p> 1996 1996 <p id="rfc.section.5.7.p.2">A client that uses persistent connections and sends more than one request per connection <em class="bcp14">MUST</em> maintain a list of outstanding requests in the order sent on that connection and <em class="bcp14">MUST</em> associate each received response message to the highest ordered request that has not yet received a final (non-1xx) response. … … 2137 2137 <p id="rfc.section.6.3.2.2.p.2">Clients which assume persistent connections and pipeline immediately after connection establishment <em class="bcp14">SHOULD</em> be prepared to retry their connection if the first pipelined attempt fails. If a client does such a retry, it <em class="bcp14">MUST NOT</em> pipeline before it knows the connection is persistent. Clients <em class="bcp14">MUST</em> also be prepared to resend their requests if the server closes the connection before sending all of the corresponding responses. 2138 2138 </p> 2139 <p id="rfc.section.6.3.2.2.p.3">Clients <em class="bcp14">SHOULD NOT</em> pipeline requests using non-idempotent request methods or non-idempotent sequences of request methods (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 2.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.1 2"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Otherwise, a premature termination of the transport connection could lead to indeterminate results. A client wishing to2139 <p id="rfc.section.6.3.2.2.p.3">Clients <em class="bcp14">SHOULD NOT</em> pipeline requests using non-idempotent request methods or non-idempotent sequences of request methods (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 2.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.16"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Otherwise, a premature termination of the transport connection could lead to indeterminate results. A client wishing to 2140 2140 send a non-idempotent request <em class="bcp14">SHOULD</em> wait to send that request until it has received the response status line for the previous request. 2141 2141 </p> … … 2167 2167 <h3 id="rfc.section.6.3.4"><a href="#rfc.section.6.3.4">6.3.4</a> <a id="persistent.retrying.requests" href="#persistent.retrying.requests">Retrying Requests</a></h3> 2168 2168 <p id="rfc.section.6.3.4.p.1">Senders can close the transport connection at any time. Therefore, clients, servers, and proxies <em class="bcp14">MUST</em> be able to recover from asynchronous close events. Client software <em class="bcp14">MAY</em> reopen the transport connection and retransmit the aborted sequence of requests without user interaction so long as the request 2169 sequence is idempotent (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 2.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.1 3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Non-idempotent request methods or sequences <em class="bcp14">MUST NOT</em> be automatically retried, although user agents <em class="bcp14">MAY</em> offer a human operator the choice of retrying the request(s). Confirmation by user-agent software with semantic understanding2169 sequence is idempotent (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 2.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.17"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Non-idempotent request methods or sequences <em class="bcp14">MUST NOT</em> be automatically retried, although user agents <em class="bcp14">MAY</em> offer a human operator the choice of retrying the request(s). Confirmation by user-agent software with semantic understanding 2170 2170 of the application <em class="bcp14">MAY</em> substitute for user confirmation. The automatic retry <em class="bcp14">SHOULD NOT</em> be repeated if the second sequence of requests fails. 2171 2171 </p> … … 2180 2180 </p> 2181 2181 <h3 id="rfc.section.6.4.3"><a href="#rfc.section.6.4.3">6.4.3</a> <a id="use.of.the.100.status" href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></h3> 2182 <p id="rfc.section.6.4.3.p.1">The purpose of the 100 (Continue) status code (see <a href="p2-semantics.html#status.100" title="100 Continue">Section 4.3.1</a> of <a href="#Part2" id="rfc.xref.Part2.1 4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) is to allow a client that is sending a request message with a request body to determine if the origin server is willing2182 <p id="rfc.section.6.4.3.p.1">The purpose of the 100 (Continue) status code (see <a href="p2-semantics.html#status.100" title="100 Continue">Section 4.3.1</a> of <a href="#Part2" id="rfc.xref.Part2.18"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) is to allow a client that is sending a request message with a request body to determine if the origin server is willing 2183 2183 to accept the request (based on the request header fields) before the client sends the request body. In some cases, it might 2184 2184 either be inappropriate or highly inefficient for the client to send the body if the server will reject the message without … … 2187 2187 <p id="rfc.section.6.4.3.p.2">Requirements for HTTP/1.1 clients: </p> 2188 2188 <ul> 2189 <li>If a client will wait for a 100 (Continue) response before sending the request body, it <em class="bcp14">MUST</em> send an Expect header field (<a href="p2-semantics.html#header.expect" title="Expect">Section 7.3</a> of <a href="#Part2" id="rfc.xref.Part2.1 5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) with the "100-continue" expectation.2190 </li> 2191 <li>A client <em class="bcp14">MUST NOT</em> send an Expect header field (<a href="p2-semantics.html#header.expect" title="Expect">Section 7.3</a> of <a href="#Part2" id="rfc.xref.Part2. 16"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) with the "100-continue" expectation if it does not intend to send a request body.2189 <li>If a client will wait for a 100 (Continue) response before sending the request body, it <em class="bcp14">MUST</em> send an Expect header field (<a href="p2-semantics.html#header.expect" title="Expect">Section 7.3</a> of <a href="#Part2" id="rfc.xref.Part2.19"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) with the "100-continue" expectation. 2190 </li> 2191 <li>A client <em class="bcp14">MUST NOT</em> send an Expect header field (<a href="p2-semantics.html#header.expect" title="Expect">Section 7.3</a> of <a href="#Part2" id="rfc.xref.Part2.20"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) with the "100-continue" expectation if it does not intend to send a request body. 2192 2192 </li> 2193 2193 </ul> … … 2233 2233 <li>A proxy <em class="bcp14">MUST NOT</em> forward a 100 (Continue) response if the request message was received from an HTTP/1.0 (or earlier) client and did not include 2234 2234 an Expect header field with the "100-continue" expectation. This requirement overrides the general rule for forwarding of 2235 1xx responses (see <a href="p2-semantics.html#status.1xx" title="Informational 1xx">Section 4.3</a> of <a href="#Part2" id="rfc.xref.Part2. 17"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).2235 1xx responses (see <a href="p2-semantics.html#status.1xx" title="Informational 1xx">Section 4.3</a> of <a href="#Part2" id="rfc.xref.Part2.21"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). 2236 2236 </li> 2237 2237 </ul> … … 2270 2270 </p> 2271 2271 <p id="rfc.section.6.5.p.8">The Upgrade header field cannot be used to indicate a switch to a protocol on a different connection. For that purpose, it 2272 is more appropriate to use a 3xx redirection response (<a href="p2-semantics.html#status.3xx" title="Redirection 3xx">Section 4.5</a> of <a href="#Part2" id="rfc.xref.Part2. 18"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).2272 is more appropriate to use a 3xx redirection response (<a href="p2-semantics.html#status.3xx" title="Redirection 3xx">Section 4.5</a> of <a href="#Part2" id="rfc.xref.Part2.22"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). 2273 2273 </p> 2274 2274 <p id="rfc.section.6.5.p.9">Servers <em class="bcp14">MUST</em> include the "Upgrade" header field in 101 (Switching Protocols) responses to indicate which protocol(s) are being switched … … 2534 2534 <li>Pointer to specification text</li> 2535 2535 </ul> 2536 <p id="rfc.section.7.4.p.3">Names of transfer codings <em class="bcp14">MUST NOT</em> overlap with names of content codings (<a href="p 3-payload.html#content.codings" title="Content Codings">Section 2.2</a> of <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) unless the encoding transformation is identical, as it is the case for the compression codings defined in <a href="#compression.codings" title="Compression Codings">Section 4.2</a>.2536 <p id="rfc.section.7.4.p.3">Names of transfer codings <em class="bcp14">MUST NOT</em> overlap with names of content codings (<a href="p2-semantics.html#content.codings" title="Content Codings">Appendix D.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.23"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) unless the encoding transformation is identical, as it is the case for the compression codings defined in <a href="#compression.codings" title="Compression Codings">Section 4.2</a>. 2537 2537 </p> 2538 2538 <p id="rfc.section.7.4.p.4">Values to be added to this name space require IETF Review (see <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a> of <a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>), and <em class="bcp14">MUST</em> conform to the purpose of transfer coding defined in this section. … … 2694 2694 that most implementations will choose substantially higher limits. 2695 2695 </p> 2696 <p id="rfc.section.8.6.p.3">This specification also provides a way for servers to reject messages that have request-targets that are too long (<a href="p2-semantics.html#status.414" title="414 URI Too Long">Section 4.6.12</a> of <a href="#Part2" id="rfc.xref.Part2. 19"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) or request entities that are too large (<a href="p2-semantics.html#status.4xx" title="Client Error 4xx">Section 4.6</a> of <a href="#Part2" id="rfc.xref.Part2.20"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).2696 <p id="rfc.section.8.6.p.3">This specification also provides a way for servers to reject messages that have request-targets that are too long (<a href="p2-semantics.html#status.414" title="414 URI Too Long">Section 4.6.12</a> of <a href="#Part2" id="rfc.xref.Part2.24"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) or request entities that are too large (<a href="p2-semantics.html#status.4xx" title="Client Error 4xx">Section 4.6</a> of <a href="#Part2" id="rfc.xref.Part2.25"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). 2697 2697 </p> 2698 2698 <p id="rfc.section.8.6.p.4">Other fields (including but not limited to request methods, response status phrases, header field-names, and body chunks) <em class="bcp14">SHOULD</em> be limited by implementations carefully, so as to not impede interoperability. … … 2738 2738 <h2 id="rfc.references.1"><a href="#rfc.section.10.1" id="rfc.section.10.1">10.1</a> Normative References 2739 2739 </h2> 2740 <table> 2740 <table> 2741 2741 <tr> 2742 2742 <td class="reference"><b id="ISO-8859-1">[ISO-8859-1]</b></td> … … 2746 2746 <td class="reference"><b id="Part2">[Part2]</b></td> 2747 2747 <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-latest">HTTP/1.1, part 2: Message Semantics</a>”, Internet-Draft draft-ietf-httpbis-p2-semantics-latest (work in progress), March 2012. 2748 </td>2749 </tr>2750 <tr>2751 <td class="reference"><b id="Part3">[Part3]</b></td>2752 <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p3-payload-latest">HTTP/1.1, part 3: Message Payload and Content Negotiation</a>”, Internet-Draft draft-ietf-httpbis-p3-payload-latest (work in progress), March 2012.2753 2748 </td> 2754 2749 </tr> … … 3750 3745 <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul> 3751 3746 <li><em>Pad1995</em> <a href="#rfc.xref.Pad1995.1">6.3.1</a>, <a href="#Pad1995"><b>10.2</b></a></li> 3752 <li><em>Part2</em> <a href="#rfc.xref.Part2.1">2.3</a>, <a href="#rfc.xref.Part2.2">2.7.1</a>, <a href="#rfc.xref.Part2.3">3.1.1</a>, <a href="#rfc.xref.Part2.4">3.1.1</a>, <a href="#rfc.xref.Part2.5">3.1.2</a>, <a href="#rfc.xref.Part2.6">3.2</a>, <a href="#rfc.xref.Part2.7">3.2</a>, <a href="#rfc.xref.Part2.8">5.1</a>, <a href="#rfc.xref.Part2.9">5.3</a>, <a href="#rfc.xref.Part2.10">5.3</a>, <a href="#rfc.xref.Part2.11">5.7</a>, <a href="#rfc.xref.Part2.12">6.3.2.2</a>, <a href="#rfc.xref.Part2.13">6.3.4</a>, <a href="#rfc.xref.Part2.14">6.4.3</a>, <a href="#rfc.xref.Part2.15">6.4.3</a>, <a href="#rfc.xref.Part2.16">6.4.3</a>, <a href="#rfc.xref.Part2.17">6.4.3</a>, <a href="#rfc.xref.Part2.18">6.5</a>, <a href="#rfc.xref.Part2.19">8.6</a>, <a href="#rfc.xref.Part2.20">8.6</a>, <a href="#Part2"><b>10.1</b></a><ul> 3753 <li><em>Section 2</em> <a href="#rfc.xref.Part2.3">3.1.1</a></li> 3754 <li><em>Section 2.1.2</em> <a href="#rfc.xref.Part2.12">6.3.2.2</a>, <a href="#rfc.xref.Part2.13">6.3.4</a></li> 3755 <li><em>Section 2.3.1</em> <a href="#rfc.xref.Part2.10">5.3</a></li> 3756 <li><em>Section 2.3.8</em> <a href="#rfc.xref.Part2.9">5.3</a></li> 3757 <li><em>Section 3.1</em> <a href="#rfc.xref.Part2.7">3.2</a></li> 3758 <li><em>Section 4</em> <a href="#rfc.xref.Part2.2">2.7.1</a>, <a href="#rfc.xref.Part2.5">3.1.2</a></li> 3759 <li><em>Section 4.3</em> <a href="#rfc.xref.Part2.11">5.7</a>, <a href="#rfc.xref.Part2.17">6.4.3</a></li> 3760 <li><em>Section 4.3.1</em> <a href="#rfc.xref.Part2.14">6.4.3</a></li> 3761 <li><em>Section 4.4.4</em> <a href="#rfc.xref.Part2.1">2.3</a></li> 3762 <li><em>Section 4.5</em> <a href="#rfc.xref.Part2.18">6.5</a></li> 3763 <li><em>Section 4.6</em> <a href="#rfc.xref.Part2.20">8.6</a></li> 3764 <li><em>Section 4.6.12</em> <a href="#rfc.xref.Part2.4">3.1.1</a>, <a href="#rfc.xref.Part2.19">8.6</a></li> 3765 <li><em>Section 7.2</em> <a href="#rfc.xref.Part2.6">3.2</a></li> 3766 <li><em>Section 7.3</em> <a href="#rfc.xref.Part2.15">6.4.3</a>, <a href="#rfc.xref.Part2.16">6.4.3</a></li> 3767 </ul> 3768 </li> 3769 <li><em>Part3</em> <a href="#rfc.xref.Part3.1">1</a>, <a href="#rfc.xref.Part3.2">3.3.1</a>, <a href="#rfc.xref.Part3.3">4.3.1</a>, <a href="#rfc.xref.Part3.4">5.6.2</a>, <a href="#rfc.xref.Part3.5">7.4</a>, <a href="#Part3"><b>10.1</b></a><ul> 3770 <li><em>Section 2.2</em> <a href="#rfc.xref.Part3.2">3.3.1</a>, <a href="#rfc.xref.Part3.5">7.4</a></li> 3771 <li><em>Section 5</em> <a href="#rfc.xref.Part3.3">4.3.1</a></li> 3772 <li><em>Appendix A</em> <a href="#rfc.xref.Part3.1">1</a></li> 3747 <li><em>Part2</em> <a href="#rfc.xref.Part2.1">1</a>, <a href="#rfc.xref.Part2.2">2.3</a>, <a href="#rfc.xref.Part2.3">2.7.1</a>, <a href="#rfc.xref.Part2.4">3.1.1</a>, <a href="#rfc.xref.Part2.5">3.1.1</a>, <a href="#rfc.xref.Part2.6">3.1.2</a>, <a href="#rfc.xref.Part2.7">3.2</a>, <a href="#rfc.xref.Part2.8">3.2</a>, <a href="#rfc.xref.Part2.9">3.3.1</a>, <a href="#rfc.xref.Part2.10">4.3.1</a>, <a href="#rfc.xref.Part2.11">5.1</a>, <a href="#rfc.xref.Part2.12">5.3</a>, <a href="#rfc.xref.Part2.13">5.3</a>, <a href="#rfc.xref.Part2.14">5.6.2</a>, <a href="#rfc.xref.Part2.15">5.7</a>, <a href="#rfc.xref.Part2.16">6.3.2.2</a>, <a href="#rfc.xref.Part2.17">6.3.4</a>, <a href="#rfc.xref.Part2.18">6.4.3</a>, <a href="#rfc.xref.Part2.19">6.4.3</a>, <a href="#rfc.xref.Part2.20">6.4.3</a>, <a href="#rfc.xref.Part2.21">6.4.3</a>, <a href="#rfc.xref.Part2.22">6.5</a>, <a href="#rfc.xref.Part2.23">7.4</a>, <a href="#rfc.xref.Part2.24">8.6</a>, <a href="#rfc.xref.Part2.25">8.6</a>, <a href="#Part2"><b>10.1</b></a><ul> 3748 <li><em>Section 2</em> <a href="#rfc.xref.Part2.4">3.1.1</a></li> 3749 <li><em>Section 2.1.2</em> <a href="#rfc.xref.Part2.16">6.3.2.2</a>, <a href="#rfc.xref.Part2.17">6.3.4</a></li> 3750 <li><em>Section 2.3.1</em> <a href="#rfc.xref.Part2.13">5.3</a></li> 3751 <li><em>Section 2.3.8</em> <a href="#rfc.xref.Part2.12">5.3</a></li> 3752 <li><em>Section 3.1</em> <a href="#rfc.xref.Part2.8">3.2</a></li> 3753 <li><em>Section 4</em> <a href="#rfc.xref.Part2.3">2.7.1</a>, <a href="#rfc.xref.Part2.6">3.1.2</a></li> 3754 <li><em>Section 4.3</em> <a href="#rfc.xref.Part2.15">5.7</a>, <a href="#rfc.xref.Part2.21">6.4.3</a></li> 3755 <li><em>Section 4.3.1</em> <a href="#rfc.xref.Part2.18">6.4.3</a></li> 3756 <li><em>Section 4.4.4</em> <a href="#rfc.xref.Part2.2">2.3</a></li> 3757 <li><em>Section 4.5</em> <a href="#rfc.xref.Part2.22">6.5</a></li> 3758 <li><em>Section 4.6</em> <a href="#rfc.xref.Part2.25">8.6</a></li> 3759 <li><em>Section 4.6.12</em> <a href="#rfc.xref.Part2.5">3.1.1</a>, <a href="#rfc.xref.Part2.24">8.6</a></li> 3760 <li><em>Section 7.2</em> <a href="#rfc.xref.Part2.7">3.2</a></li> 3761 <li><em>Section 7.3</em> <a href="#rfc.xref.Part2.19">6.4.3</a>, <a href="#rfc.xref.Part2.20">6.4.3</a></li> 3762 <li><em>Appendix D.1.2</em> <a href="#rfc.xref.Part2.9">3.3.1</a>, <a href="#rfc.xref.Part2.23">7.4</a></li> 3763 <li><em>Appendix D.4</em> <a href="#rfc.xref.Part2.10">4.3.1</a></li> 3764 <li><em>Appendix D.8</em> <a href="#rfc.xref.Part2.1">1</a></li> 3773 3765 </ul> 3774 3766 </li> -
draft-ietf-httpbis/latest/p1-messaging.xml
r1635 r1643 18 18 <!ENTITY caching-overview "<xref target='Part6' x:rel='#caching.overview' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 19 19 <!ENTITY cache-incomplete "<xref target='Part6' x:rel='#response.cacheability' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 20 <!ENTITY payload "<xref target='Part 3' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">21 <!ENTITY media-types "<xref target='Part 3' x:rel='#media.types' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">22 <!ENTITY content-codings "<xref target='Part 3' x:rel='#content.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">20 <!ENTITY payload "<xref target='Part2' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 21 <!ENTITY media-types "<xref target='Part2' x:rel='#media.types' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 22 <!ENTITY content-codings "<xref target='Part2' x:rel='#content.codings' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 23 23 <!ENTITY CONNECT "<xref target='Part2' x:rel='#CONNECT' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 24 <!ENTITY content.negotiation "<xref target='Part 3' x:rel='#content.negotiation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">25 <!ENTITY diff-mime "<xref target='Part 3' x:rel='#differences.between.http.and.mime' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">26 <!ENTITY representation "<xref target='Part 3' x:rel='#representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">24 <!ENTITY content.negotiation "<xref target='Part2' x:rel='#content.negotiation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 25 <!ENTITY diff-mime "<xref target='Part2' x:rel='#differences.between.http.and.mime' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 26 <!ENTITY representation "<xref target='Part2' x:rel='#representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 27 27 <!ENTITY header-cache-control "<xref target='Part6' x:rel='#header.cache-control' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 28 28 <!ENTITY header-date "<xref target='Part2' x:rel='#header.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 29 29 <!ENTITY header-expect "<xref target='Part2' x:rel='#header.expect' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 30 <!ENTITY header-mime-version "<xref target='Part 3' x:rel='#mime-version' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">30 <!ENTITY header-mime-version "<xref target='Part2' x:rel='#mime-version' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 31 31 <!ENTITY header-pragma "<xref target='Part6' x:rel='#header.pragma' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 32 32 <!ENTITY header-warning "<xref target='Part6' x:rel='#header.warning' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 4094 4094 </reference> 4095 4095 4096 <reference anchor="Part3">4097 <front>4098 <title abbrev="HTTP/1.1">HTTP/1.1, part 3: Message Payload and Content Negotiation</title>4099 <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">4100 <organization abbrev="Adobe">Adobe Systems Incorporated</organization>4101 <address><email>fielding@gbiv.com</email></address>4102 </author>4103 <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">4104 <organization abbrev="W3C">World Wide Web Consortium</organization>4105 <address><email>ylafon@w3.org</email></address>4106 </author>4107 <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">4108 <organization abbrev="greenbytes">greenbytes GmbH</organization>4109 <address><email>julian.reschke@greenbytes.de</email></address>4110 </author>4111 <date month="&ID-MONTH;" year="&ID-YEAR;"/>4112 </front>4113 <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p3-payload-&ID-VERSION;"/>4114 <x:source href="p3-payload.xml" basename="p3-payload"/>4115 </reference>4116 4117 4096 <reference anchor="Part6"> 4118 4097 <front> -
draft-ietf-httpbis/latest/p2-semantics.html
r1642 r1643 496 496 <link rel="Appendix" title="B Collected ABNF" href="#rfc.section.B"> 497 497 <link rel="Appendix" title="C Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.C"> 498 <link rel="Appendix" title="D THE TEXT FORMERLY KNOWN AS PART3" href="#rfc.section.D"> 498 499 <link href="p1-messaging.html" rel="prev"> 499 500 <link href="p3-payload.html" rel="next"> … … 754 755 </ul> 755 756 </li> 757 <li>D. <a href="#rfc.section.D">THE TEXT FORMERLY KNOWN AS PART3</a><ul> 758 <li>D.1 <a href="#protocol.parameters">Protocol Parameters</a><ul> 759 <li>D.1.1 <a href="#character.sets">Character Encodings (charset)</a></li> 760 <li>D.1.2 <a href="#content.codings">Content Codings</a><ul> 761 <li>D.1.2.1 <a href="#content.coding.registry">Content Coding Registry</a></li> 762 </ul> 763 </li> 764 <li>D.1.3 <a href="#media.types">Media Types</a><ul> 765 <li>D.1.3.1 <a href="#canonicalization.and.text.defaults">Canonicalization and Text Defaults</a></li> 766 <li>D.1.3.2 <a href="#multipart.types">Multipart Types</a></li> 767 </ul> 768 </li> 769 <li>D.1.4 <a href="#language.tags">Language Tags</a></li> 770 </ul> 771 </li> 772 <li>D.2 <a href="#payload">Payload</a><ul> 773 <li>D.2.1 <a href="#payload.header.fields">Payload Header Fields</a></li> 774 <li>D.2.2 <a href="#payload.body">Payload Body</a></li> 775 </ul> 776 </li> 777 <li>D.3 <a href="#representation3">Representation</a><ul> 778 <li>D.3.1 <a href="#representation.header.fields">Representation Header Fields</a></li> 779 <li>D.3.2 <a href="#representation.data">Representation Data</a></li> 780 </ul> 781 </li> 782 <li>D.4 <a href="#content.negotiation">Content Negotiation</a><ul> 783 <li>D.4.1 <a href="#server-driven.negotiation">Server-driven Negotiation</a></li> 784 <li>D.4.2 <a href="#agent-driven.negotiation">Agent-driven Negotiation</a></li> 785 </ul> 786 </li> 787 <li>D.5 <a href="#header.field.definitions3">Header Field Definitions</a><ul> 788 <li>D.5.1 <a href="#header.accept">Accept</a></li> 789 <li>D.5.2 <a href="#header.accept-charset">Accept-Charset</a></li> 790 <li>D.5.3 <a href="#header.accept-encoding">Accept-Encoding</a></li> 791 <li>D.5.4 <a href="#header.accept-language">Accept-Language</a></li> 792 <li>D.5.5 <a href="#header.content-encoding">Content-Encoding</a></li> 793 <li>D.5.6 <a href="#header.content-language">Content-Language</a></li> 794 <li>D.5.7 <a href="#header.content-location">Content-Location</a></li> 795 <li>D.5.8 <a href="#header.content-type">Content-Type</a></li> 796 </ul> 797 </li> 798 <li>D.6 <a href="#IANA.considerations3">IANA Considerations</a><ul> 799 <li>D.6.1 <a href="#content.coding.registration">Content Coding Registry</a></li> 800 </ul> 801 </li> 802 <li>D.7 <a href="#security.considerations3">Security Considerations</a><ul> 803 <li>D.7.1 <a href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></li> 804 </ul> 805 </li> 806 <li>D.8 <a href="#differences.between.http.and.mime">Differences between HTTP and MIME</a><ul> 807 <li>D.8.1 <a href="#mime-version">MIME-Version</a></li> 808 <li>D.8.2 <a href="#conversion.to.canonical.form">Conversion to Canonical Form</a></li> 809 <li>D.8.3 <a href="#conversion.of.date.formats">Conversion of Date Formats</a></li> 810 <li>D.8.4 <a href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></li> 811 <li>D.8.5 <a href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></li> 812 <li>D.8.6 <a href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></li> 813 <li>D.8.7 <a href="#mhtml.line.length">MHTML and Line Length Limitations</a></li> 814 </ul> 815 </li> 816 <li>D.9 <a href="#additional.features">Additional Features</a></li> 817 <li>D.10 <a href="#changes.from.rfc.2616-3">Changes from RFC 2616</a></li> 818 <li>D.11 <a href="#change.log3">Change Log (to be removed by RFC Editor before publication)</a><ul> 819 <li>D.11.1 <a href="#rfc.section.D.11.1">Since RFC 2616</a></li> 820 <li>D.11.2 <a href="#rfc.section.D.11.2">Since draft-ietf-httpbis-p3-payload-00</a></li> 821 <li>D.11.3 <a href="#rfc.section.D.11.3">Since draft-ietf-httpbis-p3-payload-01</a></li> 822 <li>D.11.4 <a href="#changes.3.since.02">Since draft-ietf-httpbis-p3-payload-02</a></li> 823 <li>D.11.5 <a href="#changes.3.since.03">Since draft-ietf-httpbis-p3-payload-03</a></li> 824 <li>D.11.6 <a href="#changes.3.since.04">Since draft-ietf-httpbis-p3-payload-04</a></li> 825 <li>D.11.7 <a href="#changes.3.since.05">Since draft-ietf-httpbis-p3-payload-05</a></li> 826 <li>D.11.8 <a href="#changes.3.since.06">Since draft-ietf-httpbis-p3-payload-06</a></li> 827 <li>D.11.9 <a href="#changes.3.since.07">Since draft-ietf-httpbis-p3-payload-07</a></li> 828 <li>D.11.10 <a href="#changes.3.since.08">Since draft-ietf-httpbis-p3-payload-08</a></li> 829 <li>D.11.11 <a href="#changes.3.since.09">Since draft-ietf-httpbis-p3-payload-09</a></li> 830 <li>D.11.12 <a href="#changes.3.since.10">Since draft-ietf-httpbis-p3-payload-10</a></li> 831 <li>D.11.13 <a href="#changes.3.since.11">Since draft-ietf-httpbis-p3-payload-11</a></li> 832 <li>D.11.14 <a href="#changes.3.since.12">Since draft-ietf-httpbis-p3-payload-12</a></li> 833 <li>D.11.15 <a href="#changes.3.since.13">Since draft-ietf-httpbis-p3-payload-13</a></li> 834 <li>D.11.16 <a href="#changes.3.since.14">Since draft-ietf-httpbis-p3-payload-14</a></li> 835 <li>D.11.17 <a href="#changes.3.since.15">Since draft-ietf-httpbis-p3-payload-15</a></li> 836 <li>D.11.18 <a href="#changes.3.since.16">Since draft-ietf-httpbis-p3-payload-16</a></li> 837 <li>D.11.19 <a href="#changes.3.since.17">Since draft-ietf-httpbis-p3-payload-17</a></li> 838 <li>D.11.20 <a href="#changes.3.since.18">Since draft-ietf-httpbis-p3-payload-18</a></li> 839 <li>D.11.21 <a href="#changes.3.since.19">Since draft-ietf-httpbis-p3-payload-19</a></li> 840 </ul> 841 </li> 842 </ul> 843 </li> 756 844 <li><a href="#rfc.index">Index</a></li> 757 845 </ul> … … 973 1061 a Location header field (see <a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section 7.5</a>). 974 1062 </p> 975 <p id="rfc.section.2.3.4.p.5">Responses to POST requests are only cacheable when they include explicit freshness information (see <a href="p6-cache.html#calculating.freshness.lifetime" title="Calculating Freshness Lifetime">Section 2.3.1</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). A cached POST response with a Content-Location header field (see <a href=" p3-payload.html#header.content-location" title="Content-Location">Section 6.7</a> of <a href="#Part3" id="rfc.xref.Part3.1"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.1063 <p id="rfc.section.2.3.4.p.5">Responses to POST requests are only cacheable when they include explicit freshness information (see <a href="p6-cache.html#calculating.freshness.lifetime" title="Calculating Freshness Lifetime">Section 2.3.1</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). A cached POST response with a Content-Location header field (see <a href="#header.content-location" id="rfc.xref.header.content-location.1" title="Content-Location">Appendix D.5.7</a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests. 976 1064 </p> 977 1065 <p id="rfc.section.2.3.4.p.6">Note that POST caching is not widely implemented. However, the 303 (See Other) response can be used to direct the user agent … … 1136 1224 double quotes will likely cause unnecessary confusion. 1137 1225 </p> 1138 <p id="rfc.section.3.1.p.8">Many header fields use a format including (case-insensitively) named parameters (for instance, Content-Type, defined in <a href=" p3-payload.html#header.content-type" title="Content-Type">Section 6.8</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing1226 <p id="rfc.section.3.1.p.8">Many header fields use a format including (case-insensitively) named parameters (for instance, Content-Type, defined in <a href="#header.content-type" id="rfc.xref.header.content-type.1" title="Content-Type">Appendix D.5.8</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing 1139 1227 parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for 1140 it (for an example, see the notes on parameter handling for media types in <a href=" p3-payload.html#media.types" title="Media Types">Section 2.3</a> of <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).1228 it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Appendix D.1.3</a>). 1141 1229 </p> 1142 1230 <p id="rfc.section.3.1.p.9">Authors of specifications defining new header fields are advised to consider documenting: </p> … … 1193 1281 <tr> 1194 1282 <td class="left">Accept</td> 1195 <td class="left"><a href=" p3-payload.html#header.accept" title="Accept">Section 6.1</a> of <a href="#Part3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>1283 <td class="left"><a href="#header.accept" id="rfc.xref.header.accept.1" title="Accept">Appendix D.5.1</a></td> 1196 1284 </tr> 1197 1285 <tr> 1198 1286 <td class="left">Accept-Charset</td> 1199 <td class="left"><a href=" p3-payload.html#header.accept-charset" title="Accept-Charset">Section 6.2</a> of <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>1287 <td class="left"><a href="#header.accept-charset" id="rfc.xref.header.accept-charset.1" title="Accept-Charset">Appendix D.5.2</a></td> 1200 1288 </tr> 1201 1289 <tr> 1202 1290 <td class="left">Accept-Encoding</td> 1203 <td class="left"><a href=" p3-payload.html#header.accept-encoding" title="Accept-Encoding">Section 6.3</a> of <a href="#Part3" id="rfc.xref.Part3.6"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>1291 <td class="left"><a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.1" title="Accept-Encoding">Appendix D.5.3</a></td> 1204 1292 </tr> 1205 1293 <tr> 1206 1294 <td class="left">Accept-Language</td> 1207 <td class="left"><a href=" p3-payload.html#header.accept-language" title="Accept-Language">Section 6.4</a> of <a href="#Part3" id="rfc.xref.Part3.7"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>1295 <td class="left"><a href="#header.accept-language" id="rfc.xref.header.accept-language.1" title="Accept-Language">Appendix D.5.4</a></td> 1208 1296 </tr> 1209 1297 <tr> … … 1349 1437 </ul> 1350 1438 <p id="rfc.section.4.p.4">For most status codes the response can carry a payload, in which case a Content-Type header field indicates the payload's 1351 media type (<a href=" p3-payload.html#header.content-type" title="Content-Type">Section 6.8</a> of <a href="#Part3" id="rfc.xref.Part3.8"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).1439 media type (<a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Appendix D.5.8</a>). 1352 1440 </p> 1353 1441 <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a> <a id="overview.of.status.codes" href="#overview.of.status.codes">Overview of Status Codes</a></h2> … … 1728 1816 </li> 1729 1817 <li> 1730 <p>Redirection offering a choice of matching resources for use by agent-driven content negotiation (<a href=" p3-payload.html#agent-driven.negotiation" title="Agent-driven Negotiation">Section 5.2</a> of <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>). This is status code 300 (Multiple Choices).1818 <p>Redirection offering a choice of matching resources for use by agent-driven content negotiation (<a href="#agent-driven.negotiation" title="Agent-driven Negotiation">Appendix D.4.2</a>). This is status code 300 (Multiple Choices). 1731 1819 </p> 1732 1820 </li> … … 1760 1848 <h3 id="rfc.section.4.5.1"><a href="#rfc.section.4.5.1">4.5.1</a> <a id="status.300" href="#status.300">300 Multiple Choices</a></h3> 1761 1849 <p id="rfc.section.4.5.1.p.1">The target resource has more than one representation, each with its own specific location, and agent-driven negotiation information 1762 (<a href=" p3-payload.html#content.negotiation" title="Content Negotiation">Section 5</a> of <a href="#Part3" id="rfc.xref.Part3.10"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) is being provided so that the user (or user agent) can select a preferred representation by redirecting its request to that1850 (<a href="#content.negotiation" title="Content Negotiation">Appendix D.4</a>) is being provided so that the user (or user agent) can select a preferred representation by redirecting its request to that 1763 1851 location. 1764 1852 </p> … … 1882 1970 <h3 id="rfc.section.4.6.6"><a href="#rfc.section.4.6.6">4.6.6</a> <a id="status.406" href="#status.406">406 Not Acceptable</a></h3> 1883 1971 <p id="rfc.section.4.6.6.p.1">The resource identified by the request is only capable of generating response representations which have content characteristics 1884 not acceptable according to the Accept and Accept-* header fields sent in the request (see <a href="p3-payload.html#header.field.definitions" title="Header Field Definitions">Section 6</a> of <a href="#Part3" id="rfc.xref.Part3.11"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>).1972 not acceptable according to the Accept and Accept-* header fields sent in the request. 1885 1973 </p> 1886 1974 <p id="rfc.section.4.6.6.p.2">Unless it was a HEAD request, the response <em class="bcp14">SHOULD</em> include a representation containing a list of available representation characteristics and location(s) from which the user … … 2033 2121 <p id="rfc.section.5.p.1">Request and Response messages <em class="bcp14">MAY</em> transfer a representation if not otherwise restricted by the request method or response status code. A representation consists 2034 2122 of metadata (representation header fields) and data (representation body). When a complete or partial representation is enclosed 2035 in an HTTP message, it is referred to as the payload of the message. HTTP representations are defined in <a href="#Part3" id="rfc.xref.Part3.12"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.2123 in an HTTP message, it is referred to as the payload of the message. 2036 2124 </p> 2037 2125 <p id="rfc.section.5.p.2">A representation body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.37"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. The representation body is obtained from the message body by decoding any Transfer-Encoding that might have been applied … … 2282 2370 </p> 2283 2371 <div class="note" id="rfc.section.7.5.p.9"> 2284 <p> <b>Note:</b> The Content-Location header field (<a href=" p3-payload.html#header.content-location" title="Content-Location">Section 6.7</a> of <a href="#Part3" id="rfc.xref.Part3.13"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.2372 <p> <b>Note:</b> The Content-Location header field (<a href="#header.content-location" id="rfc.xref.header.content-location.2" title="Content-Location">Appendix D.5.7</a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation. 2285 2373 It is therefore possible for a response to contain header fields for both Location and Content-Location. 2286 2374 </p> … … 2693 2781 <tbody> 2694 2782 <tr> 2783 <td class="left">Accept</td> 2784 <td class="left">http</td> 2785 <td class="left">standard</td> 2786 <td class="left"> <a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Appendix D.5.1</a> 2787 </td> 2788 </tr> 2789 <tr> 2790 <td class="left">Accept-Charset</td> 2791 <td class="left">http</td> 2792 <td class="left">standard</td> 2793 <td class="left"> <a href="#header.accept-charset" id="rfc.xref.header.accept-charset.2" title="Accept-Charset">Appendix D.5.2</a> 2794 </td> 2795 </tr> 2796 <tr> 2797 <td class="left">Accept-Encoding</td> 2798 <td class="left">http</td> 2799 <td class="left">standard</td> 2800 <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.2" title="Accept-Encoding">Appendix D.5.3</a> 2801 </td> 2802 </tr> 2803 <tr> 2804 <td class="left">Accept-Language</td> 2805 <td class="left">http</td> 2806 <td class="left">standard</td> 2807 <td class="left"> <a href="#header.accept-language" id="rfc.xref.header.accept-language.2" title="Accept-Language">Appendix D.5.4</a> 2808 </td> 2809 </tr> 2810 <tr> 2695 2811 <td class="left">Allow</td> 2696 2812 <td class="left">http</td> … … 2700 2816 </tr> 2701 2817 <tr> 2818 <td class="left">Content-Encoding</td> 2819 <td class="left">http</td> 2820 <td class="left">standard</td> 2821 <td class="left"> <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Appendix D.5.5</a> 2822 </td> 2823 </tr> 2824 <tr> 2825 <td class="left">Content-Language</td> 2826 <td class="left">http</td> 2827 <td class="left">standard</td> 2828 <td class="left"> <a href="#header.content-language" id="rfc.xref.header.content-language.1" title="Content-Language">Appendix D.5.6</a> 2829 </td> 2830 </tr> 2831 <tr> 2832 <td class="left">Content-Location</td> 2833 <td class="left">http</td> 2834 <td class="left">standard</td> 2835 <td class="left"> <a href="#header.content-location" id="rfc.xref.header.content-location.3" title="Content-Location">Appendix D.5.7</a> 2836 </td> 2837 </tr> 2838 <tr> 2839 <td class="left">Content-Type</td> 2840 <td class="left">http</td> 2841 <td class="left">standard</td> 2842 <td class="left"> <a href="#header.content-type" id="rfc.xref.header.content-type.3" title="Content-Type">Appendix D.5.8</a> 2843 </td> 2844 </tr> 2845 <tr> 2702 2846 <td class="left">Date</td> 2703 2847 <td class="left">http</td> … … 2725 2869 <td class="left">standard</td> 2726 2870 <td class="left"> <a href="#header.location" id="rfc.xref.header.location.4" title="Location">Section 7.5</a> 2871 </td> 2872 </tr> 2873 <tr> 2874 <td class="left">MIME-Version</td> 2875 <td class="left">http</td> 2876 <td class="left">standard</td> 2877 <td class="left"> <a href="#mime-version" id="rfc.xref.mime-version.1" title="MIME-Version">Appendix D.8.1</a> 2727 2878 </td> 2728 2879 </tr> … … 2836 2987 <h2 id="rfc.references.1"><a href="#rfc.section.11.1" id="rfc.section.11.1">11.1</a> Normative References 2837 2988 </h2> 2838 <table> 2989 <table> 2839 2990 <tr> 2840 2991 <td class="reference"><b id="Part1">[Part1]</b></td> 2841 2992 <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-latest">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</a>”, Internet-Draft draft-ietf-httpbis-p1-messaging-latest (work in progress), March 2012. 2842 </td>2843 </tr>2844 <tr>2845 <td class="reference"><b id="Part3">[Part3]</b></td>2846 <td class="top"><a href="mailto:fielding@gbiv.com" title="Adobe Systems Incorporated">Fielding, R., Ed.</a>, <a href="mailto:ylafon@w3.org" title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a href="mailto:julian.reschke@greenbytes.de" title="greenbytes GmbH">J. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p3-payload-latest">HTTP/1.1, part 3: Message Payload and Content Negotiation</a>”, Internet-Draft draft-ietf-httpbis-p3-payload-latest (work in progress), March 2012.2847 2993 </td> 2848 2994 </tr> … … 3082 3228 </p> 3083 3229 <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a> <a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1> 3084 <div id="rfc.figure.u.37"></div> <pre class="inline"><a href="#header.allow" class="smpl">Allow</a> = [ ( "," / method ) *( OWS "," [ OWS method ] ) ] 3230 <div id="rfc.figure.u.37"></div> <pre class="inline"><a href="#header.accept" class="smpl">Accept</a> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [ 3231 OWS media-range [ accept-params ] ] ) ] 3232 <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q=" 3233 qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q=" 3234 qvalue ] ] ) 3235 <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) ) 3236 *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ] 3237 <a href="#header.accept-language" class="smpl">Accept-Language</a> = *( "," OWS ) language-range [ OWS ";" OWS "q=" 3238 qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ] 3239 ] ) 3240 <a href="#header.allow" class="smpl">Allow</a> = [ ( "," / method ) *( OWS "," [ OWS method ] ) ] 3085 3241 3086 3242 <a href="#core.rules" class="smpl">BWS</a> = <BWS, defined in [Part1], Section 3.2.1> 3087 3243 3244 <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = *( "," OWS ) content-coding *( OWS "," [ OWS 3245 content-coding ] ) 3246 <a href="#header.content-language" class="smpl">Content-Language</a> = *( "," OWS ) language-tag *( OWS "," [ OWS 3247 language-tag ] ) 3248 <a href="#header.content-location" class="smpl">Content-Location</a> = absolute-URI / partial-URI 3249 <a href="#header.content-type" class="smpl">Content-Type</a> = media-type 3250 3088 3251 <a href="#header.date" class="smpl">Date</a> = HTTP-date 3089 3252 … … 3098 3261 <a href="#header.location" class="smpl">Location</a> = URI-reference 3099 3262 3263 <a href="#mime-version" class="smpl">MIME-Version</a> = 1*DIGIT "." 1*DIGIT 3264 3100 3265 <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*DIGIT 3101 3266 … … 3103 3268 3104 3269 <a href="#core.rules" class="smpl">RWS</a> = <RWS, defined in [Part1], Section 3.2.1> 3270 3105 3271 <a href="#header.referer" class="smpl">Referer</a> = absolute-URI / partial-URI 3106 3272 <a href="#header.retry-after" class="smpl">Retry-After</a> = HTTP-date / delta-seconds … … 3109 3275 3110 3276 <a href="#abnf.dependencies" class="smpl">URI-reference</a> = <URI-reference, defined in [Part1], Section 2.7> 3277 3111 3278 <a href="#header.user-agent" class="smpl">User-Agent</a> = product *( RWS ( product / comment ) ) 3112 3279 3113 3280 <a href="#abnf.dependencies" class="smpl">absolute-URI</a> = <absolute-URI, defined in [Part1], Section 2.7> 3281 3282 <a href="#header.accept" class="smpl">accept-ext</a> = OWS ";" OWS token [ "=" word ] 3283 <a href="#header.accept" class="smpl">accept-params</a> = OWS ";" OWS "q=" qvalue *accept-ext 3114 3284 <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = day-name SP date3 SP time-of-day SP year 3115 3285 <a href="#rule.parameter" class="smpl">attribute</a> = token 3286 3287 <a href="#rule.charset" class="smpl">charset</a> = token 3288 3289 <a href="#header.accept-encoding" class="smpl">codings</a> = content-coding / "identity" / "*" 3116 3290 <a href="#abnf.dependencies" class="smpl">comment</a> = <comment, defined in [Part1], Section 3.2.4> 3291 <a href="#content.codings" class="smpl">content-coding</a> = token 3117 3292 3118 3293 <a href="#obsolete.date.formats" class="smpl">date1</a> = day SP month SP year 3294 3119 3295 <a href="#obsolete.date.formats" class="smpl">date2</a> = day "-" month "-" 2DIGIT 3120 3296 <a href="#obsolete.date.formats" class="smpl">date3</a> = month SP ( 2DIGIT / ( SP DIGIT ) ) … … 3137 3313 3138 3314 <a href="#header.expect" class="smpl">expect-name</a> = token 3315 3139 3316 <a href="#header.expect" class="smpl">expect-param</a> = expect-name [ BWS "=" BWS expect-value ] 3140 3317 <a href="#header.expect" class="smpl">expect-value</a> = token / quoted-string … … 3144 3321 <a href="#preferred.date.format" class="smpl">hour</a> = 2DIGIT 3145 3322 3323 <a href="#header.accept-language" class="smpl">language-range</a> = <language-range, defined in [RFC4647], Section 2.1> 3324 3325 <a href="#language.tags" class="smpl">language-tag</a> = <Language-Tag, defined in [RFC5646], Section 2.1> 3326 3146 3327 <a href="#header.from" class="smpl">mailbox</a> = <mailbox, defined in [RFC5322], Section 3.4> 3328 3329 <a href="#header.accept" class="smpl">media-range</a> = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS 3330 ";" OWS parameter ) 3331 <a href="#media.types" class="smpl">media-type</a> = type "/" subtype *( OWS ";" OWS parameter ) 3147 3332 <a href="#methods" class="smpl">method</a> = token 3148 3333 <a href="#preferred.date.format" class="smpl">minute</a> = 2DIGIT … … 3161 3346 3162 3347 <a href="#obsolete.date.formats" class="smpl">obs-date</a> = rfc850-date / asctime-date 3348 3163 3349 <a href="#core.rules" class="smpl">obs-text</a> = <obs-text, defined in [Part1], Section 3.2.4> 3350 3351 <a href="#rule.parameter" class="smpl">parameter</a> = attribute "=" value 3164 3352 3165 3353 <a href="#abnf.dependencies" class="smpl">partial-URI</a> = <partial-URI, defined in [Part1], Section 2.7> … … 3170 3358 3171 3359 <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = day-name "," SP date1 SP time-of-day SP GMT 3360 3172 3361 <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> = day-name-l "," SP date2 SP time-of-day SP GMT 3173 3362 3174 3363 <a href="#preferred.date.format" class="smpl">second</a> = 2DIGIT 3175 3364 3365 <a href="#media.types" class="smpl">subtype</a> = token 3366 3176 3367 <a href="#preferred.date.format" class="smpl">time-of-day</a> = hour ":" minute ":" second 3368 3177 3369 <a href="#core.rules" class="smpl">token</a> = <token, defined in [Part1], Section 3.2.4> 3178 3179 word = <word, defined in [Part1], Section 3.2.4> 3370 <a href="#media.types" class="smpl">type</a> = token 3371 3372 <a href="#rule.parameter" class="smpl">value</a> = word 3373 3374 <a href="#core.rules" class="smpl">word</a> = <word, defined in [Part1], Section 3.2.4> 3180 3375 3181 3376 <a href="#preferred.date.format" class="smpl">year</a> = 4DIGIT 3182 3377 </pre> <div id="rfc.figure.u.38"></div> 3183 <p>ABNF diagnostics:</p><pre class="inline">; Allow defined but not used 3378 <p>ABNF diagnostics:</p><pre class="inline">; qvalue UNDEFINED 3379 ; Accept defined but not used 3380 ; Accept-Charset defined but not used 3381 ; Accept-Encoding defined but not used 3382 ; Accept-Language defined but not used 3383 ; Allow defined but not used 3384 ; Content-Encoding defined but not used 3385 ; Content-Language defined but not used 3386 ; Content-Location defined but not used 3387 ; Content-Type defined but not used 3184 3388 ; Date defined but not used 3185 3389 ; Expect defined but not used 3186 3390 ; From defined but not used 3187 3391 ; Location defined but not used 3392 ; MIME-Version defined but not used 3188 3393 ; Max-Forwards defined but not used 3189 3394 ; Referer defined but not used … … 3192 3397 ; User-Agent defined but not used 3193 3398 ; obs-text defined but not used 3194 ; word defined but not used3195 3399 </pre><h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a> <a id="change.log" href="#change.log">Change Log (to be removed by RFC Editor before publication)</a></h1> 3196 3400 <h2 id="rfc.section.C.1"><a href="#rfc.section.C.1">C.1</a> Since RFC 2616 … … 3516 3720 </li> 3517 3721 </ul> 3722 <h1 id="rfc.section.D"><a href="#rfc.section.D">D.</a> THE TEXT FORMERLY KNOWN AS PART3 3723 </h1> 3724 <h2 id="rfc.section.D.1"><a href="#rfc.section.D.1">D.1</a> <a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h2> 3725 <h3 id="rfc.section.D.1.1"><a href="#rfc.section.D.1.1">D.1.1</a> <a id="character.sets" href="#character.sets">Character Encodings (charset)</a></h3> 3726 <p id="rfc.section.D.1.1.p.1">HTTP uses charset names to indicate the character encoding of a textual representation.</p> 3727 <div id="rule.charset"> 3728 <p id="rfc.section.D.1.1.p.2"> A character encoding is identified by a case-insensitive token. The complete set of tokens is defined by the IANA Character 3729 Set registry (<<a href="http://www.iana.org/assignments/character-sets">http://www.iana.org/assignments/character-sets</a>>). 3730 </p> 3731 </div> 3732 <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.36"></span> <a href="#rule.charset" class="smpl">charset</a> = <a href="#core.rules" class="smpl">token</a> 3733 </pre><p id="rfc.section.D.1.1.p.4">Although HTTP allows an arbitrary token to be used as a charset value, any token that has a predefined value within the IANA 3734 Character Set registry <em class="bcp14">MUST</em> represent the character encoding defined by that registry. Applications <em class="bcp14">SHOULD</em> limit their use of character encodings to those defined within the IANA registry. 3735 </p> 3736 <p id="rfc.section.D.1.1.p.5">HTTP uses charset in two contexts: within an Accept-Charset request header field (in which the charset value is an unquoted 3737 token) and as the value of a parameter in a Content-Type header field (within a request or response), in which case the parameter 3738 value of the charset parameter can be quoted. 3739 </p> 3740 <p id="rfc.section.D.1.1.p.6">Implementors need to be aware of IETF character set requirements <a href="#RFC3629" id="rfc.xref.RFC3629.1"><cite title="UTF-8, a transformation format of ISO 10646">[RFC3629]</cite></a> <a href="#RFC2277" id="rfc.xref.RFC2277.1"><cite title="IETF Policy on Character Sets and Languages">[RFC2277]</cite></a>. 3741 </p> 3742 <h3 id="rfc.section.D.1.2"><a href="#rfc.section.D.1.2">D.1.2</a> <a id="content.codings" href="#content.codings">Content Codings</a></h3> 3743 <p id="rfc.section.D.1.2.p.1">Content coding values indicate an encoding transformation that has been or can be applied to a representation. Content codings 3744 are primarily used to allow a representation to be compressed or otherwise usefully transformed without losing the identity 3745 of its underlying media type and without loss of information. Frequently, the representation is stored in coded form, transmitted 3746 directly, and only decoded by the recipient. 3747 </p> 3748 <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.37"></span> <a href="#content.codings" class="smpl">content-coding</a> = <a href="#core.rules" class="smpl">token</a> 3749 </pre><p id="rfc.section.D.1.2.p.3">All content-coding values are case-insensitive. HTTP/1.1 uses content-coding values in the Accept-Encoding (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.3" title="Accept-Encoding">Appendix D.5.3</a>) and Content-Encoding (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.2" title="Content-Encoding">Appendix D.5.5</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding 3750 mechanism will be required to remove the encoding. 3751 </p> 3752 <p id="rfc.section.D.1.2.p.4">compress<span id="rfc.iref.c.3"></span><span id="rfc.iref.c.4"></span> 3753 </p> 3754 <ul class="empty"> 3755 <li>See <a href="p1-messaging.html#compress.coding" title="Compress Coding">Section 4.2.1</a> of <a href="#Part1" id="rfc.xref.Part1.45"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. 3756 </li> 3757 </ul> 3758 <p id="rfc.section.D.1.2.p.5">deflate<span id="rfc.iref.d.3"></span><span id="rfc.iref.c.5"></span> 3759 </p> 3760 <ul class="empty"> 3761 <li>See <a href="p1-messaging.html#deflate.coding" title="Deflate Coding">Section 4.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.46"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. 3762 </li> 3763 </ul> 3764 <p id="rfc.section.D.1.2.p.6">gzip<span id="rfc.iref.g.38"></span><span id="rfc.iref.c.6"></span> 3765 </p> 3766 <ul class="empty"> 3767 <li>See <a href="p1-messaging.html#gzip.coding" title="Gzip Coding">Section 4.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.47"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. 3768 </li> 3769 </ul> 3770 <h4 id="rfc.section.D.1.2.1"><a href="#rfc.section.D.1.2.1">D.1.2.1</a> <a id="content.coding.registry" href="#content.coding.registry">Content Coding Registry</a></h4> 3771 <p id="rfc.section.D.1.2.1.p.1">The HTTP Content Coding Registry defines the name space for the content coding names.</p> 3772 <p id="rfc.section.D.1.2.1.p.2">Registrations <em class="bcp14">MUST</em> include the following fields: 3773 </p> 3774 <ul> 3775 <li>Name</li> 3776 <li>Description</li> 3777 <li>Pointer to specification text</li> 3778 </ul> 3779 <p id="rfc.section.D.1.2.1.p.3">Names of content codings <em class="bcp14">MUST NOT</em> overlap with names of transfer codings (<a href="p1-messaging.html#transfer.codings" title="Transfer Codings">Section 4</a> of <a href="#Part1" id="rfc.xref.Part1.48"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>), unless the encoding transformation is identical (as is the case for the compression codings defined in <a href="p1-messaging.html#compression.codings" title="Compression Codings">Section 4.2</a> of <a href="#Part1" id="rfc.xref.Part1.49"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). 3780 </p> 3781 <p id="rfc.section.D.1.2.1.p.4">Values to be added to this name space require IETF Review (see <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a> of <a href="#RFC5226" id="rfc.xref.RFC5226.3"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>), and <em class="bcp14">MUST</em> conform to the purpose of content coding defined in this section. 3782 </p> 3783 <p id="rfc.section.D.1.2.1.p.5">The registry itself is maintained at <<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>>. 3784 </p> 3785 <h3 id="rfc.section.D.1.3"><a href="#rfc.section.D.1.3">D.1.3</a> <a id="media.types" href="#media.types">Media Types</a></h3> 3786 <p id="rfc.section.D.1.3.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> in the Content-Type (<a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Appendix D.5.8</a>) and Accept (<a href="#header.accept" id="rfc.xref.header.accept.3" title="Accept">Appendix D.5.1</a>) header fields in order to provide open and extensible data typing and type negotiation. 3787 </p> 3788 <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.39"></span><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span> <a href="#media.types" class="smpl">media-type</a> = <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> *( <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> ) 3789 <a href="#media.types" class="smpl">type</a> = <a href="#core.rules" class="smpl">token</a> 3790 <a href="#media.types" class="smpl">subtype</a> = <a href="#core.rules" class="smpl">token</a> 3791 </pre><div id="rule.parameter"> 3792 <p id="rfc.section.D.1.3.p.3"> The type/subtype <em class="bcp14">MAY</em> be followed by parameters in the form of attribute/value pairs. 3793 </p> 3794 </div> 3795 <div id="rfc.figure.u.42"></div><pre class="inline"><span id="rfc.iref.g.42"></span><span id="rfc.iref.g.43"></span><span id="rfc.iref.g.44"></span> <a href="#rule.parameter" class="smpl">parameter</a> = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a> 3796 <a href="#rule.parameter" class="smpl">attribute</a> = <a href="#core.rules" class="smpl">token</a> 3797 <a href="#rule.parameter" class="smpl">value</a> = <a href="#core.rules" class="smpl">word</a> 3798 </pre><p id="rfc.section.D.1.3.p.5">The type, subtype, and parameter attribute names are case-insensitive. Parameter values might or might not be case-sensitive, 3799 depending on the semantics of the parameter name. The presence or absence of a parameter might be significant to the processing 3800 of a media-type, depending on its definition within the media type registry. 3801 </p> 3802 <p id="rfc.section.D.1.3.p.6">A parameter value that matches the <a href="#core.rules" class="smpl">token</a> production can be transmitted as either a token or within a quoted-string. The quoted and unquoted values are equivalent. 3803 </p> 3804 <p id="rfc.section.D.1.3.p.7">Note that some older HTTP applications do not recognize media type parameters. When sending data to older HTTP applications, 3805 implementations <em class="bcp14">SHOULD</em> only use media type parameters when they are required by that type/subtype definition. 3806 </p> 3807 <p id="rfc.section.D.1.3.p.8">Media-type values are registered with the Internet Assigned Number Authority (IANA). The media type registration process is 3808 outlined in <a href="#RFC4288" id="rfc.xref.RFC4288.1"><cite title="Media Type Specifications and Registration Procedures">[RFC4288]</cite></a>. Use of non-registered media types is discouraged. 3809 </p> 3810 <h4 id="rfc.section.D.1.3.1"><a href="#rfc.section.D.1.3.1">D.1.3.1</a> <a id="canonicalization.and.text.defaults" href="#canonicalization.and.text.defaults">Canonicalization and Text Defaults</a></h4> 3811 <p id="rfc.section.D.1.3.1.p.1">Internet media types are registered with a canonical form. A representation transferred via HTTP messages <em class="bcp14">MUST</em> be in the appropriate canonical form prior to its transmission except for "text" types, as defined in the next paragraph. 3812 </p> 3813 <p id="rfc.section.D.1.3.1.p.2">When in canonical form, media subtypes of the "text" type use CRLF as the text line break. HTTP relaxes this requirement and 3814 allows the transport of text media with plain CR or LF alone representing a line break when it is done consistently for an 3815 entire representation. HTTP applications <em class="bcp14">MUST</em> accept CRLF, bare CR, and bare LF as indicating a line break in text media received via HTTP. In addition, if the text is 3816 in a character encoding that does not use octets 13 and 10 for CR and LF respectively, as is the case for some multi-byte 3817 character encodings, HTTP allows the use of whatever octet sequences are defined by that character encoding to represent the 3818 equivalent of CR and LF for line breaks. This flexibility regarding line breaks applies only to text media in the payload 3819 body; a bare CR or LF <em class="bcp14">MUST NOT</em> be substituted for CRLF within any of the HTTP control structures (such as header fields and multipart boundaries). 3820 </p> 3821 <p id="rfc.section.D.1.3.1.p.3">If a representation is encoded with a content-coding, the underlying data <em class="bcp14">MUST</em> be in a form defined above prior to being encoded. 3822 </p> 3823 <h4 id="rfc.section.D.1.3.2"><a href="#rfc.section.D.1.3.2">D.1.3.2</a> <a id="multipart.types" href="#multipart.types">Multipart Types</a></h4> 3824 <p id="rfc.section.D.1.3.2.p.1">MIME provides for a number of "multipart" types — encapsulations of one or more representations within a single message body. 3825 All multipart types share a common syntax, as defined in <a href="http://tools.ietf.org/html/rfc2046#section-5.1.1">Section 5.1.1</a> of <a href="#RFC2046" id="rfc.xref.RFC2046.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a>, and <em class="bcp14">MUST</em> include a boundary parameter as part of the media type value. The message body is itself a protocol element and <em class="bcp14">MUST</em> therefore use only CRLF to represent line breaks between body-parts. 3826 </p> 3827 <p id="rfc.section.D.1.3.2.p.2">In general, HTTP treats a multipart message body no differently than any other media type: strictly as payload. HTTP does 3828 not use the multipart boundary as an indicator of message body length. In all other respects, an HTTP user agent <em class="bcp14">SHOULD</em> follow the same or similar behavior as a MIME user agent would upon receipt of a multipart type. The MIME header fields within 3829 each body-part of a multipart message body do not have any significance to HTTP beyond that defined by their MIME semantics. 3830 </p> 3831 <p id="rfc.section.D.1.3.2.p.3">If an application receives an unrecognized multipart subtype, the application <em class="bcp14">MUST</em> treat it as being equivalent to "multipart/mixed". 3832 </p> 3833 <div class="note" id="rfc.section.D.1.3.2.p.4"> 3834 <p> <b>Note:</b> The "multipart/form-data" type has been specifically defined for carrying form data suitable for processing via the POST request 3835 method, as described in <a href="#RFC2388" id="rfc.xref.RFC2388.1"><cite title="Returning Values from Forms: multipart/form-data">[RFC2388]</cite></a>. 3836 </p> 3837 </div> 3838 <h3 id="rfc.section.D.1.4"><a href="#rfc.section.D.1.4">D.1.4</a> <a id="language.tags" href="#language.tags">Language Tags</a></h3> 3839 <p id="rfc.section.D.1.4.p.1">A language tag, as defined in <a href="#RFC5646" id="rfc.xref.RFC5646.1"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a>, identifies a natural language spoken, written, or otherwise conveyed by human beings for communication of information to 3840 other human beings. Computer languages are explicitly excluded. HTTP uses language tags within the Accept-Language and Content-Language 3841 fields. 3842 </p> 3843 <p id="rfc.section.D.1.4.p.2">In summary, a language tag is composed of one or more parts: A primary language subtag followed by a possibly empty series 3844 of subtags: 3845 </p> 3846 <div id="rfc.figure.u.43"></div><pre class="inline"><span id="rfc.iref.g.45"></span> <a href="#language.tags" class="smpl">language-tag</a> = <Language-Tag, defined in <a href="#RFC5646" id="rfc.xref.RFC5646.2"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a>, <a href="http://tools.ietf.org/html/rfc5646#section-2.1">Section 2.1</a>> 3847 </pre><p id="rfc.section.D.1.4.p.4">White space is not allowed within the tag and all tags are case-insensitive. The name space of language subtags is administered 3848 by the IANA (see <<a href="http://www.iana.org/assignments/language-subtag-registry">http://www.iana.org/assignments/language-subtag-registry</a>>). 3849 </p> 3850 <div id="rfc.figure.u.44"></div> 3851 <p>Example tags include:</p> <pre class="text"> en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN 3852 </pre> <p id="rfc.section.D.1.4.p.6">See <a href="#RFC5646" id="rfc.xref.RFC5646.3"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a> for further information. 3853 </p> 3854 <h2 id="rfc.section.D.2"><a href="#rfc.section.D.2">D.2</a> <a id="payload" href="#payload">Payload</a></h2> 3855 <p id="rfc.section.D.2.p.1">HTTP messages <em class="bcp14">MAY</em> transfer a payload if not otherwise restricted by the request method or response status code. The payload consists of metadata, 3856 in the form of header fields, and data, in the form of the sequence of octets in the message body after any transfer-coding 3857 has been decoded. 3858 </p> 3859 <div id="rfc.iref.p.3"></div> 3860 <p id="rfc.section.D.2.p.2">A "<dfn>payload</dfn>" in HTTP is always a partial or complete representation of some resource. We use separate terms for payload and representation 3861 because some messages contain only the associated representation's header fields (e.g., responses to HEAD) or only some part(s) 3862 of the representation (e.g., the 206 status code). 3863 </p> 3864 <h3 id="rfc.section.D.2.1"><a href="#rfc.section.D.2.1">D.2.1</a> <a id="payload.header.fields" href="#payload.header.fields">Payload Header Fields</a></h3> 3865 <p id="rfc.section.D.2.1.p.1">HTTP header fields that specifically define the payload, rather than the associated representation, are referred to as "payload 3866 header fields". The following payload header fields are defined by HTTP/1.1: 3867 </p> 3868 <div id="rfc.table.u.4"> 3869 <table class="tt full left" cellpadding="3" cellspacing="0"> 3870 <thead> 3871 <tr> 3872 <th>Header Field Name</th> 3873 <th>Defined in...</th> 3874 </tr> 3875 </thead> 3876 <tbody> 3877 <tr> 3878 <td class="left">Content-Length</td> 3879 <td class="left"><a href="p1-messaging.html#header.content-length" title="Content-Length">Section 3.3.2</a> of <a href="#Part1" id="rfc.xref.Part1.50"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a></td> 3880 </tr> 3881 <tr> 3882 <td class="left">Content-Range</td> 3883 <td class="left"><a href="p5-range.html#header.content-range" title="Content-Range">Section 5.2</a> of <a href="#Part5" id="rfc.xref.Part5.8"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td> 3884 </tr> 3885 </tbody> 3886 </table> 3887 </div> 3888 <h3 id="rfc.section.D.2.2"><a href="#rfc.section.D.2.2">D.2.2</a> <a id="payload.body" href="#payload.body">Payload Body</a></h3> 3889 <p id="rfc.section.D.2.2.p.1">A payload body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.51"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. The payload body is obtained from the message body by decoding any Transfer-Encoding that might have been applied to ensure 3890 safe and proper transfer of the message. 3891 </p> 3892 <div id="rfc.iref.r.3"></div> 3893 <h2 id="rfc.section.D.3"><a href="#rfc.section.D.3">D.3</a> <a id="representation3" href="#representation3">Representation</a></h2> 3894 <p id="rfc.section.D.3.p.1">A "<dfn>representation</dfn>" is information in a format that can be readily communicated from one party to another. A resource representation is information 3895 that reflects the state of that resource, as observed at some point in the past (e.g., in a response to GET) or to be desired 3896 at some point in the future (e.g., in a PUT request). 3897 </p> 3898 <p id="rfc.section.D.3.p.2">Most, but not all, representations transferred via HTTP are intended to be a representation of the target resource (the resource 3899 identified by the effective request URI). The precise semantics of a representation are determined by the type of message 3900 (request or response), the request method, the response status code, and the representation metadata. For example, the above 3901 semantic is true for the representation in any 200 (OK) response to GET and for the representation in any PUT request. A 200 3902 response to PUT, in contrast, contains either a representation that describes the successful action or a representation of 3903 the target resource, with the latter indicated by a Content-Location header field with the same value as the effective request 3904 URI. Likewise, response messages with an error status code usually contain a representation that describes the error and what 3905 next steps are suggested for resolving it. 3906 </p> 3907 <h3 id="rfc.section.D.3.1"><a href="#rfc.section.D.3.1">D.3.1</a> <a id="representation.header.fields" href="#representation.header.fields">Representation Header Fields</a></h3> 3908 <p id="rfc.section.D.3.1.p.1">Representation header fields define metadata about the representation data enclosed in the message body or, if no message 3909 body is present, about the representation that would have been transferred in a 200 response to a simultaneous GET request 3910 with the same effective request URI. 3911 </p> 3912 <p id="rfc.section.D.3.1.p.2">The following header fields are defined as representation metadata:</p> 3913 <div id="rfc.table.u.5"> 3914 <table class="tt full left" cellpadding="3" cellspacing="0"> 3915 <thead> 3916 <tr> 3917 <th>Header Field Name</th> 3918 <th>Defined in...</th> 3919 </tr> 3920 </thead> 3921 <tbody> 3922 <tr> 3923 <td class="left">Content-Encoding</td> 3924 <td class="left"><a href="#header.content-encoding" id="rfc.xref.header.content-encoding.3" title="Content-Encoding">Appendix D.5.5</a></td> 3925 </tr> 3926 <tr> 3927 <td class="left">Content-Language</td> 3928 <td class="left"><a href="#header.content-language" id="rfc.xref.header.content-language.2" title="Content-Language">Appendix D.5.6</a></td> 3929 </tr> 3930 <tr> 3931 <td class="left">Content-Location</td> 3932 <td class="left"><a href="#header.content-location" id="rfc.xref.header.content-location.4" title="Content-Location">Appendix D.5.7</a></td> 3933 </tr> 3934 <tr> 3935 <td class="left">Content-Type</td> 3936 <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.5" title="Content-Type">Appendix D.5.8</a></td> 3937 </tr> 3938 <tr> 3939 <td class="left">Expires</td> 3940 <td class="left"><a href="p6-cache.html#header.expires" title="Expires">Section 3.3</a> of <a href="#Part6" id="rfc.xref.Part6.18"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td> 3941 </tr> 3942 </tbody> 3943 </table> 3944 </div> 3945 <p id="rfc.section.D.3.1.p.3">Additional header fields define metadata about the selected representation, which might differ from the representation included 3946 in the message for responses to some state-changing methods. The following header fields are defined as selected representation 3947 metadata: 3948 </p> 3949 <div id="rfc.table.u.6"> 3950 <table class="tt full left" cellpadding="3" cellspacing="0"> 3951 <thead> 3952 <tr> 3953 <th>Header Field Name</th> 3954 <th>Defined in...</th> 3955 </tr> 3956 </thead> 3957 <tbody> 3958 <tr> 3959 <td class="left">ETag</td> 3960 <td class="left"><a href="p4-conditional.html#header.etag" title="ETag">Section 2.3</a> of <a href="#Part4" id="rfc.xref.Part4.12"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td> 3961 </tr> 3962 <tr> 3963 <td class="left">Last-Modified</td> 3964 <td class="left"><a href="p4-conditional.html#header.last-modified" title="Last-Modified">Section 2.2</a> of <a href="#Part4" id="rfc.xref.Part4.13"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td> 3965 </tr> 3966 </tbody> 3967 </table> 3968 </div> 3969 <h3 id="rfc.section.D.3.2"><a href="#rfc.section.D.3.2">D.3.2</a> <a id="representation.data" href="#representation.data">Representation Data</a></h3> 3970 <p id="rfc.section.D.3.2.p.1">The representation body associated with an HTTP message is either provided as the payload body of the message or referred 3971 to by the message semantics and the effective request URI. The representation data is in a format and encoding defined by 3972 the representation metadata header fields. 3973 </p> 3974 <p id="rfc.section.D.3.2.p.2">The data type of the representation data is determined via the header fields Content-Type and Content-Encoding. These define 3975 a two-layer, ordered encoding model: 3976 </p> 3977 <div id="rfc.figure.u.45"></div><pre class="text"> representation-data := Content-Encoding( Content-Type( bits ) ) 3978 </pre><p id="rfc.section.D.3.2.p.4">Content-Type specifies the media type of the underlying data, which defines both the data format and how that data <em class="bcp14">SHOULD</em> be processed by the recipient (within the scope of the request method semantics). Any HTTP/1.1 message containing a payload 3979 body <em class="bcp14">SHOULD</em> include a Content-Type header field defining the media type of the associated representation unless that metadata is unknown 3980 to the sender. If the Content-Type header field is not present, it indicates that the sender does not know the media type 3981 of the representation; recipients <em class="bcp14">MAY</em> either assume that the media type is "application/octet-stream" (<a href="#RFC2046" id="rfc.xref.RFC2046.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a>, <a href="http://tools.ietf.org/html/rfc2046#section-4.5.1">Section 4.5.1</a>) or examine the content to determine its type. 3982 </p> 3983 <p id="rfc.section.D.3.2.p.5">In practice, resource owners do not always properly configure their origin server to provide the correct Content-Type for 3984 a given representation, with the result that some clients will examine a response body's content and override the specified 3985 type. Clients that do so risk drawing incorrect conclusions, which might expose additional security risks (e.g., "privilege 3986 escalation"). Furthermore, it is impossible to determine the sender's intent by examining the data format: many data formats 3987 match multiple media types that differ only in processing semantics. Implementers are encouraged to provide a means of disabling 3988 such "content sniffing" when it is used. 3989 </p> 3990 <p id="rfc.section.D.3.2.p.6">Content-Encoding is used to indicate any additional content codings applied to the data, usually for the purpose of data compression, 3991 that are a property of the representation. If Content-Encoding is not present, then there is no additional encoding beyond 3992 that defined by the Content-Type. 3993 </p> 3994 <h2 id="rfc.section.D.4"><a href="#rfc.section.D.4">D.4</a> <a id="content.negotiation" href="#content.negotiation">Content Negotiation</a></h2> 3995 <p id="rfc.section.D.4.p.1">HTTP responses include a representation which contains information for interpretation, whether by a human user or for further 3996 processing. Often, the server has different ways of representing the same information; for example, in different formats, 3997 languages, or using different character encodings. 3998 </p> 3999 <p id="rfc.section.D.4.p.2">HTTP clients and their users might have different or variable capabilities, characteristics or preferences which would influence 4000 which representation, among those available from the server, would be best for the server to deliver. For this reason, HTTP 4001 provides mechanisms for "content negotiation" — a process of allowing selection of a representation of a given resource, when 4002 more than one is available. 4003 </p> 4004 <p id="rfc.section.D.4.p.3">This specification defines two patterns of content negotiation; "server-driven", where the server selects the representation 4005 based upon the client's stated preferences, and "agent-driven" negotiation, where the server provides a list of representations 4006 for the client to choose from, based upon their metadata. In addition, there are other patterns: some applications use an 4007 "active content" pattern, where the server returns active content which runs on the client and, based on client available 4008 parameters, selects additional resources to invoke. "Transparent Content Negotiation" (<a href="#RFC2295" id="rfc.xref.RFC2295.1"><cite title="Transparent Content Negotiation in HTTP">[RFC2295]</cite></a>) has also been proposed. 4009 </p> 4010 <p id="rfc.section.D.4.p.4">These patterns are all widely used, and have trade-offs in applicability and practicality. In particular, when the number 4011 of preferences or capabilities to be expressed by a client are large (such as when many different formats are supported by 4012 a user-agent), server-driven negotiation becomes unwieldy, and might not be appropriate. Conversely, when the number of representations 4013 to choose from is very large, agent-driven negotiation might not be appropriate. 4014 </p> 4015 <p id="rfc.section.D.4.p.5">Note that in all cases, the supplier of representations has the responsibility for determining which representations might 4016 be considered to be the "same information". 4017 </p> 4018 <h3 id="rfc.section.D.4.1"><a href="#rfc.section.D.4.1">D.4.1</a> <a id="server-driven.negotiation" href="#server-driven.negotiation">Server-driven Negotiation</a></h3> 4019 <p id="rfc.section.D.4.1.p.1">If the selection of the best representation for a response is made by an algorithm located at the server, it is called server-driven 4020 negotiation. Selection is based on the available representations of the response (the dimensions over which it can vary; e.g., 4021 language, content-coding, etc.) and the contents of particular header fields in the request message or on other information 4022 pertaining to the request (such as the network address of the client). 4023 </p> 4024 <p id="rfc.section.D.4.1.p.2">Server-driven negotiation is advantageous when the algorithm for selecting from among the available representations is difficult 4025 to describe to the user agent, or when the server desires to send its "best guess" to the client along with the first response 4026 (hoping to avoid the round-trip delay of a subsequent request if the "best guess" is good enough for the user). In order to 4027 improve the server's guess, the user agent <em class="bcp14">MAY</em> include request header fields (Accept, Accept-Language, Accept-Encoding, etc.) which describe its preferences for such a response. 4028 </p> 4029 <p id="rfc.section.D.4.1.p.3">Server-driven negotiation has disadvantages: </p> 4030 <ol> 4031 <li>It is impossible for the server to accurately determine what might be "best" for any given user, since that would require 4032 complete knowledge of both the capabilities of the user agent and the intended use for the response (e.g., does the user want 4033 to view it on screen or print it on paper?). 4034 </li> 4035 <li>Having the user agent describe its capabilities in every request can be both very inefficient (given that only a small percentage 4036 of responses have multiple representations) and a potential violation of the user's privacy. 4037 </li> 4038 <li>It complicates the implementation of an origin server and the algorithms for generating responses to a request.</li> 4039 <li>It might limit a public cache's ability to use the same response for multiple user's requests.</li> 4040 </ol> 4041 <p id="rfc.section.D.4.1.p.4">Server-driven negotiation allows the user agent to specify its preferences, but it cannot expect responses to always honor 4042 them. For example, the origin server might not implement server-driven negotiation, or it might decide that sending a response 4043 that doesn't conform to them is better than sending a 406 (Not Acceptable) response. 4044 </p> 4045 <p id="rfc.section.D.4.1.p.5">Many of the mechanisms for expressing preferences use quality values to declare relative preference. See <a href="p1-messaging.html#quality.values" title="Quality Values">Section 4.3.1</a> of <a href="#Part1" id="rfc.xref.Part1.52"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for more information. 4046 </p> 4047 <p id="rfc.section.D.4.1.p.6">HTTP/1.1 includes the following header fields for enabling server-driven negotiation through description of user agent capabilities 4048 and user preferences: Accept (<a href="#header.accept" id="rfc.xref.header.accept.4" title="Accept">Appendix D.5.1</a>), Accept-Charset (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Appendix D.5.2</a>), Accept-Encoding (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.4" title="Accept-Encoding">Appendix D.5.3</a>), Accept-Language (<a href="#header.accept-language" id="rfc.xref.header.accept-language.3" title="Accept-Language">Appendix D.5.4</a>), and User-Agent (<a href="#header.user-agent" id="rfc.xref.header.user-agent.4" title="User-Agent">Section 7.10</a>). However, an origin server is not limited to these dimensions and <em class="bcp14">MAY</em> vary the response based on any aspect of the request, including aspects of the connection (e.g., IP address) or information 4049 within extension header fields not defined by this specification. 4050 </p> 4051 <div class="note" id="rfc.section.D.4.1.p.7"> 4052 <p> <b>Note:</b> In practice, User-Agent based negotiation is fragile, because new clients might not be recognized. 4053 </p> 4054 </div> 4055 <p id="rfc.section.D.4.1.p.8">The Vary header field (<a href="p6-cache.html#header.vary" title="Vary">Section 3.5</a> of <a href="#Part6" id="rfc.xref.Part6.19"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) can be used to express the parameters the server uses to select a representation that is subject to server-driven negotiation. 4056 </p> 4057 <h3 id="rfc.section.D.4.2"><a href="#rfc.section.D.4.2">D.4.2</a> <a id="agent-driven.negotiation" href="#agent-driven.negotiation">Agent-driven Negotiation</a></h3> 4058 <p id="rfc.section.D.4.2.p.1">With agent-driven negotiation, selection of the best representation for a response is performed by the user agent after receiving 4059 an initial response from the origin server. Selection is based on a list of the available representations of the response 4060 included within the header fields or body of the initial response, with each representation identified by its own URI. Selection 4061 from among the representations can be performed automatically (if the user agent is capable of doing so) or manually by the 4062 user selecting from a generated (possibly hypertext) menu. 4063 </p> 4064 <p id="rfc.section.D.4.2.p.2">Agent-driven negotiation is advantageous when the response would vary over commonly-used dimensions (such as type, language, 4065 or encoding), when the origin server is unable to determine a user agent's capabilities from examining the request, and generally 4066 when public caches are used to distribute server load and reduce network usage. 4067 </p> 4068 <p id="rfc.section.D.4.2.p.3">Agent-driven negotiation suffers from the disadvantage of needing a second request to obtain the best alternate representation. 4069 This second request is only efficient when caching is used. In addition, this specification does not define any mechanism 4070 for supporting automatic selection, though it also does not prevent any such mechanism from being developed as an extension 4071 and used within HTTP/1.1. 4072 </p> 4073 <p id="rfc.section.D.4.2.p.4">This specification defines the 300 (Multiple Choices) and 406 (Not Acceptable) status codes for enabling agent-driven negotiation 4074 when the server is unwilling or unable to provide a varying response using server-driven negotiation. 4075 </p> 4076 <h2 id="rfc.section.D.5"><a href="#rfc.section.D.5">D.5</a> <a id="header.field.definitions3" href="#header.field.definitions3">Header Field Definitions</a></h2> 4077 <p id="rfc.section.D.5.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to the payload of messages.</p> 4078 <div id="rfc.iref.a.2"></div> 4079 <div id="rfc.iref.h.12"></div> 4080 <h3 id="rfc.section.D.5.1"><a href="#rfc.section.D.5.1">D.5.1</a> <a id="header.accept" href="#header.accept">Accept</a></h3> 4081 <p id="rfc.section.D.5.1.p.1">The "Accept" header field can be used by user agents to specify response media types that are acceptable. Accept header fields 4082 can be used to indicate that the request is specifically limited to a small set of desired types, as in the case of a request 4083 for an in-line image. 4084 </p> 4085 <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.46"></span><span id="rfc.iref.g.47"></span><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span> <a href="#header.accept" class="smpl">Accept</a> = #( <a href="#header.accept" class="smpl">media-range</a> [ <a href="#header.accept" class="smpl">accept-params</a> ] ) 4086 4087 <a href="#header.accept" class="smpl">media-range</a> = ( "*/*" 4088 / ( <a href="#media.types" class="smpl">type</a> "/" "*" ) 4089 / ( <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> ) 4090 ) *( <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> ) 4091 <a href="#header.accept" class="smpl">accept-params</a> = <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> "q=" <a href="#abnf.dependencies" class="smpl">qvalue</a> *( <a href="#header.accept" class="smpl">accept-ext</a> ) 4092 <a href="#header.accept" class="smpl">accept-ext</a> = <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> <a href="#core.rules" class="smpl">token</a> [ "=" <a href="#core.rules" class="smpl">word</a> ] 4093 </pre><p id="rfc.section.D.5.1.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating 4094 all subtypes of that type. The media-range <em class="bcp14">MAY</em> include media type parameters that are applicable to that range. 4095 </p> 4096 <p id="rfc.section.D.5.1.p.4">Each media-range <em class="bcp14">MAY</em> be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative quality factor. The first 4097 "q" parameter (if any) separates the media-range parameter(s) from the accept-params. Quality factors allow the user or user 4098 agent to indicate the relative degree of preference for that media-range, using the qvalue scale from 0 to 1 (<a href="p1-messaging.html#quality.values" title="Quality Values">Section 4.3.1</a> of <a href="#Part1" id="rfc.xref.Part1.53"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). The default value is q=1. 4099 </p> 4100 <div class="note" id="rfc.section.D.5.1.p.5"> 4101 <p> <b>Note:</b> Use of the "q" parameter name to separate media type parameters from Accept extension parameters is due to historical practice. 4102 Although this prevents any media type parameter named "q" from being used with a media range, such an event is believed to 4103 be unlikely given the lack of any "q" parameters in the IANA media type registry and the rare usage of any media type parameters 4104 in Accept. Future media types are discouraged from registering any parameter named "q". 4105 </p> 4106 </div> 4107 <p id="rfc.section.D.5.1.p.6">The example</p> 4108 <div id="rfc.figure.u.47"></div><pre class="text"> Accept: audio/*; q=0.2, audio/basic 4109 </pre><p id="rfc.section.D.5.1.p.8"> <em class="bcp14">SHOULD</em> be interpreted as "I prefer audio/basic, but send me any audio type if it is the best available after an 80% mark-down in 4110 quality". 4111 </p> 4112 <p id="rfc.section.D.5.1.p.9">A request without any Accept header field implies that the user agent will accept any media type in response. If an Accept 4113 header field is present in a request and none of the available representations for the response have a media type that is 4114 listed as acceptable, the origin server <em class="bcp14">MAY</em> either honor the Accept header field by sending a 406 (Not Acceptable) response or disregard the Accept header field by treating 4115 the response as if it is not subject to content negotiation. 4116 </p> 4117 <p id="rfc.section.D.5.1.p.10">A more elaborate example is</p> 4118 <div id="rfc.figure.u.48"></div><pre class="text"> Accept: text/plain; q=0.5, text/html, 4119 text/x-dvi; q=0.8, text/x-c 4120 </pre><p id="rfc.section.D.5.1.p.12">Verbally, this would be interpreted as "text/html and text/x-c are the preferred media types, but if they do not exist, then 4121 send the text/x-dvi representation, and if that does not exist, send the text/plain representation". 4122 </p> 4123 <p id="rfc.section.D.5.1.p.13">Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies 4124 to a given type, the most specific reference has precedence. For example, 4125 </p> 4126 <div id="rfc.figure.u.49"></div><pre class="text"> Accept: text/*, text/plain, text/plain;format=flowed, */* 4127 </pre><p id="rfc.section.D.5.1.p.15">have the following precedence: </p> 4128 <ol> 4129 <li>text/plain;format=flowed</li> 4130 <li>text/plain</li> 4131 <li>text/*</li> 4132 <li>*/*</li> 4133 </ol> 4134 <p id="rfc.section.D.5.1.p.16">The media type quality factor associated with a given type is determined by finding the media range with the highest precedence 4135 which matches that type. For example, 4136 </p> 4137 <div id="rfc.figure.u.50"></div><pre class="text"> Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1, 4138 text/html;level=2;q=0.4, */*;q=0.5 4139 </pre><p id="rfc.section.D.5.1.p.18">would cause the following values to be associated:</p> 4140 <div id="rfc.table.u.7"> 4141 <table class="tt full left" cellpadding="3" cellspacing="0"> 4142 <thead> 4143 <tr> 4144 <th>Media Type</th> 4145 <th>Quality Value</th> 4146 </tr> 4147 </thead> 4148 <tbody> 4149 <tr> 4150 <td class="left">text/html;level=1</td> 4151 <td class="left">1</td> 4152 </tr> 4153 <tr> 4154 <td class="left">text/html</td> 4155 <td class="left">0.7</td> 4156 </tr> 4157 <tr> 4158 <td class="left">text/plain</td> 4159 <td class="left">0.3</td> 4160 </tr> 4161 <tr> 4162 <td class="left">image/jpeg</td> 4163 <td class="left">0.5</td> 4164 </tr> 4165 <tr> 4166 <td class="left">text/html;level=2</td> 4167 <td class="left">0.4</td> 4168 </tr> 4169 <tr> 4170 <td class="left">text/html;level=3</td> 4171 <td class="left">0.7</td> 4172 </tr> 4173 </tbody> 4174 </table> 4175 </div> 4176 <p id="rfc.section.D.5.1.p.19"> <b>Note:</b> A user agent might be provided with a default set of quality values for certain media ranges. However, unless the user agent 4177 is a closed system which cannot interact with other rendering agents, this default set ought to be configurable by the user. 4178 </p> 4179 <div id="rfc.iref.a.3"></div> 4180 <div id="rfc.iref.h.13"></div> 4181 <h3 id="rfc.section.D.5.2"><a href="#rfc.section.D.5.2">D.5.2</a> <a id="header.accept-charset" href="#header.accept-charset">Accept-Charset</a></h3> 4182 <p id="rfc.section.D.5.2.p.1">The "Accept-Charset" header field can be used by user agents to indicate what character encodings are acceptable in a response 4183 payload. This field allows clients capable of understanding more comprehensive or special-purpose character encodings to signal 4184 that capability to a server which is capable of representing documents in those character encodings. 4185 </p> 4186 <div id="rfc.figure.u.51"></div><pre class="inline"><span id="rfc.iref.g.50"></span> <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = 1#( ( <a href="#rule.charset" class="smpl">charset</a> / "*" ) 4187 [ <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> "q=" <a href="#abnf.dependencies" class="smpl">qvalue</a> ] ) 4188 </pre><p id="rfc.section.D.5.2.p.3">Character encoding values (a.k.a., charsets) are described in <a href="#character.sets" title="Character Encodings (charset)">Appendix D.1.1</a>. Each charset <em class="bcp14">MAY</em> be given an associated quality value which represents the user's preference for that charset. The default value is q=1. An 4189 example is 4190 </p> 4191 <div id="rfc.figure.u.52"></div><pre class="text"> Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 4192 </pre><p id="rfc.section.D.5.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere 4193 in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then all character encodings not explicitly 4194 mentioned get a quality value of 0. 4195 </p> 4196 <p id="rfc.section.D.5.2.p.6">A request without any Accept-Charset header field implies that the user agent will accept any character encoding in response. 4197 If an Accept-Charset header field is present in a request and none of the available representations for the response have 4198 a character encoding that is listed as acceptable, the origin server <em class="bcp14">MAY</em> either honor the Accept-Charset header field by sending a 406 (Not Acceptable) response or disregard the Accept-Charset header 4199 field by treating the response as if it is not subject to content negotiation. 4200 </p> 4201 <div id="rfc.iref.a.4"></div> 4202 <div id="rfc.iref.h.14"></div> 4203 <h3 id="rfc.section.D.5.3"><a href="#rfc.section.D.5.3">D.5.3</a> <a id="header.accept-encoding" href="#header.accept-encoding">Accept-Encoding</a></h3> 4204 <p id="rfc.section.D.5.3.p.1">The "Accept-Encoding" header field can be used by user agents to indicate what response content-codings (<a href="#content.codings" title="Content Codings">Appendix D.1.2</a>) are acceptable in the response. An "identity" token is used as a synonym for "no encoding" in order to communicate when 4205 no encoding is preferred. 4206 </p> 4207 <div id="rfc.figure.u.53"></div><pre class="inline"><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span> <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> = #( <a href="#header.accept-encoding" class="smpl">codings</a> [ <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> "q=" <a href="#abnf.dependencies" class="smpl">qvalue</a> ] ) 4208 <a href="#header.accept-encoding" class="smpl">codings</a> = <a href="#content.codings" class="smpl">content-coding</a> / "identity" / "*" 4209 </pre><p id="rfc.section.D.5.3.p.3">Each codings value <em class="bcp14">MAY</em> be given an associated quality value which represents the preference for that encoding. The default value is q=1. 4210 </p> 4211 <p id="rfc.section.D.5.3.p.4">For example,</p> 4212 <div id="rfc.figure.u.54"></div><pre class="text"> Accept-Encoding: compress, gzip 4213 Accept-Encoding: 4214 Accept-Encoding: * 4215 Accept-Encoding: compress;q=0.5, gzip;q=1.0 4216 Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 4217 </pre><p id="rfc.section.D.5.3.p.6">A server tests whether a content-coding for a given representation is acceptable, according to an Accept-Encoding field, using 4218 these rules: 4219 </p> 4220 <ol> 4221 <li>The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed in the header 4222 field. 4223 </li> 4224 <li>If the representation has no content-coding, then it is acceptable by default unless specifically excluded by the Accept-Encoding 4225 field stating either "identity;q=0" or "*;q=0" without a more specific entry for "identity". 4226 </li> 4227 <li>If the representation's content-coding is one of the content-codings listed in the Accept-Encoding field, then it is acceptable 4228 unless it is accompanied by a qvalue of 0. (As defined in <a href="p1-messaging.html#quality.values" title="Quality Values">Section 4.3.1</a> of <a href="#Part1" id="rfc.xref.Part1.54"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, a qvalue of 0 means "not acceptable".) 4229 </li> 4230 <li>If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero qvalue is preferred.</li> 4231 </ol> 4232 <p id="rfc.section.D.5.3.p.7">An Accept-Encoding header field with a combined field-value that is empty implies that the user agent does not want any content-coding 4233 in response. If an Accept-Encoding header field is present in a request and none of the available representations for the 4234 response have a content-coding that is listed as acceptable, the origin server <em class="bcp14">SHOULD</em> send a response without any content-coding. 4235 </p> 4236 <p id="rfc.section.D.5.3.p.8">A request without an Accept-Encoding header field implies that the user agent will accept any content-coding in response, 4237 but a representation without content-coding is preferred for compatibility with the widest variety of user agents. 4238 </p> 4239 <div class="note" id="rfc.section.D.5.3.p.9"> 4240 <p> <b>Note:</b> Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. This means that qvalues will 4241 not work and are not permitted with x-gzip or x-compress. 4242 </p> 4243 </div> 4244 <div id="rfc.iref.a.5"></div> 4245 <div id="rfc.iref.h.15"></div> 4246 <h3 id="rfc.section.D.5.4"><a href="#rfc.section.D.5.4">D.5.4</a> <a id="header.accept-language" href="#header.accept-language">Accept-Language</a></h3> 4247 <p id="rfc.section.D.5.4.p.1">The "Accept-Language" header field can be used by user agents to indicate the set of natural languages that are preferred 4248 in the response. Language tags are defined in <a href="#language.tags" title="Language Tags">Appendix D.1.4</a>. 4249 </p> 4250 <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.53"></span><span id="rfc.iref.g.54"></span> <a href="#header.accept-language" class="smpl">Accept-Language</a> = 4251 1#( <a href="#header.accept-language" class="smpl">language-range</a> [ <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> "q=" <a href="#abnf.dependencies" class="smpl">qvalue</a> ] ) 4252 <a href="#header.accept-language" class="smpl">language-range</a> = 4253 <language-range, defined in <a href="#RFC4647" id="rfc.xref.RFC4647.1"><cite title="Matching of Language Tags">[RFC4647]</cite></a>, <a href="http://tools.ietf.org/html/rfc4647#section-2.1">Section 2.1</a>> 4254 </pre><p id="rfc.section.D.5.4.p.3">Each language-range can be given an associated quality value which represents an estimate of the user's preference for the 4255 languages specified by that range. The quality value defaults to "q=1". For example, 4256 </p> 4257 <div id="rfc.figure.u.56"></div><pre class="text"> Accept-Language: da, en-gb;q=0.8, en;q=0.7 4258 </pre><p id="rfc.section.D.5.4.p.5">would mean: "I prefer Danish, but will accept British English and other types of English". (see also <a href="http://tools.ietf.org/html/rfc4647#section-2.3">Section 2.3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.2"><cite title="Matching of Language Tags">[RFC4647]</cite></a>) 4259 </p> 4260 <p id="rfc.section.D.5.4.p.6">For matching, <a href="http://tools.ietf.org/html/rfc4647#section-3">Section 3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.3"><cite title="Matching of Language Tags">[RFC4647]</cite></a> defines several matching schemes. Implementations can offer the most appropriate matching scheme for their requirements. 4261 </p> 4262 <div class="note" id="rfc.section.D.5.4.p.7"> 4263 <p> <b>Note:</b> The "Basic Filtering" scheme (<a href="#RFC4647" id="rfc.xref.RFC4647.4"><cite title="Matching of Language Tags">[RFC4647]</cite></a>, <a href="http://tools.ietf.org/html/rfc4647#section-3.3.1">Section 3.3.1</a>) is identical to the matching scheme that was previously defined in <a href="http://tools.ietf.org/html/rfc2616#section-14.4">Section 14.4</a> of <a href="#RFC2616" id="rfc.xref.RFC2616.4"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>. 4264 </p> 4265 </div> 4266 <p id="rfc.section.D.5.4.p.8">It might be contrary to the privacy expectations of the user to send an Accept-Language header field with the complete linguistic 4267 preferences of the user in every request. For a discussion of this issue, see <a href="#privacy.issues.connected.to.accept.header.fields" title="Privacy Issues Connected to Accept Header Fields">Appendix D.7.1</a>. 4268 </p> 4269 <p id="rfc.section.D.5.4.p.9">As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice 4270 of linguistic preference available to the user. If the choice is not made available, then the Accept-Language header field <em class="bcp14">MUST NOT</em> be given in the request. 4271 </p> 4272 <div class="note" id="rfc.section.D.5.4.p.10"> 4273 <p> <b>Note:</b> When making the choice of linguistic preference available to the user, we remind implementors of the fact that users are not 4274 familiar with the details of language matching as described above, and ought to be provided appropriate guidance. As an example, 4275 users might assume that on selecting "en-gb", they will be served any kind of English document if British English is not available. 4276 A user agent might suggest in such a case to add "en" to get the best matching behavior. 4277 </p> 4278 </div> 4279 <div id="rfc.iref.c.7"></div> 4280 <div id="rfc.iref.h.16"></div> 4281 <h3 id="rfc.section.D.5.5"><a href="#rfc.section.D.5.5">D.5.5</a> <a id="header.content-encoding" href="#header.content-encoding">Content-Encoding</a></h3> 4282 <p id="rfc.section.D.5.5.p.1">The "Content-Encoding" header field indicates what content-codings have been applied to the representation beyond those inherent 4283 in the media type, and thus what decoding mechanisms have to be applied in order to obtain the media-type referenced by the 4284 Content-Type header field. Content-Encoding is primarily used to allow a representation to be compressed without losing the 4285 identity of its underlying media type. 4286 </p> 4287 <div id="rfc.figure.u.57"></div><pre class="inline"><span id="rfc.iref.g.55"></span> <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = 1#<a href="#content.codings" class="smpl">content-coding</a> 4288 </pre><p id="rfc.section.D.5.5.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Appendix D.1.2</a>. An example of its use is 4289 </p> 4290 <div id="rfc.figure.u.58"></div><pre class="text"> Content-Encoding: gzip 4291 </pre><p id="rfc.section.D.5.5.p.5">The content-coding is a characteristic of the representation. Typically, the representation body is stored with this encoding 4292 and is only decoded before rendering or analogous usage. However, a transforming proxy <em class="bcp14">MAY</em> modify the content-coding if the new coding is known to be acceptable to the recipient, unless the "no-transform" cache-control 4293 directive is present in the message. 4294 </p> 4295 <p id="rfc.section.D.5.5.p.6">If the media type includes an inherent encoding, such as a data format that is always compressed, then that encoding would 4296 not be restated as a Content-Encoding even if it happens to be the same algorithm as one of the content-codings. Such a content-coding 4297 would only be listed if, for some bizarre reason, it is applied a second time to form the representation. Likewise, an origin 4298 server might choose to publish the same payload data as multiple representations that differ only in whether the coding is 4299 defined as part of Content-Type or Content-Encoding, since some user agents will behave differently in their handling of each 4300 response (e.g., open a "Save as ..." dialog instead of automatic decompression and rendering of content). 4301 </p> 4302 <p id="rfc.section.D.5.5.p.7">A representation that has a content-coding applied to it <em class="bcp14">MUST</em> include a Content-Encoding header field (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.4" title="Content-Encoding">Appendix D.5.5</a>) that lists the content-coding(s) applied. 4303 </p> 4304 <p id="rfc.section.D.5.5.p.8">If multiple encodings have been applied to a representation, the content codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other header fields not defined by this specification. 4305 </p> 4306 <p id="rfc.section.D.5.5.p.9">If the content-coding of a representation in a request message is not acceptable to the origin server, the server <em class="bcp14">SHOULD</em> respond with a status code of 415 (Unsupported Media Type). 4307 </p> 4308 <div id="rfc.iref.c.8"></div> 4309 <div id="rfc.iref.h.17"></div> 4310 <h3 id="rfc.section.D.5.6"><a href="#rfc.section.D.5.6">D.5.6</a> <a id="header.content-language" href="#header.content-language">Content-Language</a></h3> 4311 <p id="rfc.section.D.5.6.p.1">The "Content-Language" header field describes the natural language(s) of the intended audience for the representation. Note 4312 that this might not be equivalent to all the languages used within the representation. 4313 </p> 4314 <div id="rfc.figure.u.59"></div><pre class="inline"><span id="rfc.iref.g.56"></span> <a href="#header.content-language" class="smpl">Content-Language</a> = 1#<a href="#language.tags" class="smpl">language-tag</a> 4315 </pre><p id="rfc.section.D.5.6.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Appendix D.1.4</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the 4316 user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate 4317 field is 4318 </p> 4319 <div id="rfc.figure.u.60"></div><pre class="text"> Content-Language: da 4320 </pre><p id="rfc.section.D.5.6.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean 4321 that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language 4322 it is intended. 4323 </p> 4324 <p id="rfc.section.D.5.6.p.6">Multiple languages <em class="bcp14">MAY</em> be listed for content that is intended for multiple audiences. For example, a rendition of the "Treaty of Waitangi", presented 4325 simultaneously in the original Maori and English versions, would call for 4326 </p> 4327 <div id="rfc.figure.u.61"></div><pre class="text"> Content-Language: mi, en 4328 </pre><p id="rfc.section.D.5.6.p.8">However, just because multiple languages are present within a representation does not mean that it is intended for multiple 4329 linguistic audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin", which is clearly 4330 intended to be used by an English-literate audience. In this case, the Content-Language would properly only include "en". 4331 </p> 4332 <p id="rfc.section.D.5.6.p.9">Content-Language <em class="bcp14">MAY</em> be applied to any media type — it is not limited to textual documents. 4333 </p> 4334 <div id="rfc.iref.c.9"></div> 4335 <div id="rfc.iref.h.18"></div> 4336 <h3 id="rfc.section.D.5.7"><a href="#rfc.section.D.5.7">D.5.7</a> <a id="header.content-location" href="#header.content-location">Content-Location</a></h3> 4337 <p id="rfc.section.D.5.7.p.1">The "Content-Location" header field supplies a URI that can be used as a specific identifier for the representation in this 4338 message. In other words, if one were to perform a GET on this URI at the time of this message's generation, then a 200 response 4339 would contain the same representation that is enclosed as payload in this message. 4340 </p> 4341 <div id="rfc.figure.u.62"></div><pre class="inline"><span id="rfc.iref.g.57"></span> <a href="#header.content-location" class="smpl">Content-Location</a> = <a href="#abnf.dependencies" class="smpl">absolute-URI</a> / <a href="#abnf.dependencies" class="smpl">partial-URI</a> 4342 </pre><p id="rfc.section.D.5.7.p.3">The Content-Location value is not a replacement for the effective Request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.55"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). It is representation metadata. It has the same syntax and semantics as the header field of the same name defined for MIME 4343 body parts in <a href="http://tools.ietf.org/html/rfc2557#section-4">Section 4</a> of <a href="#RFC2557" id="rfc.xref.RFC2557.1"><cite title="MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)">[RFC2557]</cite></a>. However, its appearance in an HTTP message has some special implications for HTTP recipients. 4344 </p> 4345 <p id="rfc.section.D.5.7.p.4">If Content-Location is included in a response message and its value is the same as the effective request URI, then the response 4346 payload <em class="bcp14">SHOULD</em> be considered a current representation of that resource. For a GET or HEAD request, this is the same as the default semantics 4347 when no Content-Location is provided by the server. For a state-changing request like PUT or POST, it implies that the server's 4348 response contains the new representation of that resource, thereby distinguishing it from representations that might only 4349 report about the action (e.g., "It worked!"). This allows authoring applications to update their local copies without the 4350 need for a subsequent GET request. 4351 </p> 4352 <p id="rfc.section.D.5.7.p.5">If Content-Location is included in a response message and its value differs from the effective request URI, then the origin 4353 server is informing recipients that this representation has its own, presumably more specific, identifier. For a GET or HEAD 4354 request, this is an indication that the effective request URI identifies a resource that is subject to content negotiation 4355 and the selected representation for this response can also be found at the identified URI. For other methods, such a Content-Location 4356 indicates that this representation contains a report on the action's status and the same report is available (for future access 4357 with GET) at the given URI. For example, a purchase transaction made via a POST request might include a receipt document as 4358 the payload of the 200 response; the Content-Location value provides an identifier for retrieving a copy of that same receipt 4359 in the future. 4360 </p> 4361 <p id="rfc.section.D.5.7.p.6">If Content-Location is included in a request message, then it <em class="bcp14">MAY</em> be interpreted by the origin server as an indication of where the user agent originally obtained the content of the enclosed 4362 representation (prior to any subsequent modification of the content by that user agent). In other words, the user agent is 4363 providing the same representation metadata that it received with the original representation. However, such interpretation <em class="bcp14">MUST NOT</em> be used to alter the semantics of the method requested by the client. For example, if a client makes a PUT request on a negotiated 4364 resource and the origin server accepts that PUT (without redirection), then the new set of values for that resource is expected 4365 to be consistent with the one representation supplied in that PUT; the Content-Location cannot be used as a form of reverse 4366 content selection that identifies only one of the negotiated representations to be updated. If the user agent had wanted the 4367 latter semantics, it would have applied the PUT directly to the Content-Location URI. 4368 </p> 4369 <p id="rfc.section.D.5.7.p.7">A Content-Location field received in a request message is transitory information that <em class="bcp14">SHOULD NOT</em> be saved with other representation metadata for use in later responses. The Content-Location's value might be saved for use 4370 in other contexts, such as within source links or other metadata. 4371 </p> 4372 <p id="rfc.section.D.5.7.p.8">A cache cannot assume that a representation with a Content-Location different from the URI used to retrieve it can be used 4373 to respond to later requests on that Content-Location URI. 4374 </p> 4375 <p id="rfc.section.D.5.7.p.9">If the Content-Location value is a partial URI, the partial URI is interpreted relative to the effective request URI.</p> 4376 <div id="rfc.iref.c.10"></div> 4377 <div id="rfc.iref.h.19"></div> 4378 <h3 id="rfc.section.D.5.8"><a href="#rfc.section.D.5.8">D.5.8</a> <a id="header.content-type" href="#header.content-type">Content-Type</a></h3> 4379 <p id="rfc.section.D.5.8.p.1">The "Content-Type" header field indicates the media type of the representation. In the case of responses to the HEAD method, 4380 the media type is that which would have been sent had the request been a GET. 4381 </p> 4382 <div id="rfc.figure.u.63"></div><pre class="inline"><span id="rfc.iref.g.58"></span> <a href="#header.content-type" class="smpl">Content-Type</a> = <a href="#media.types" class="smpl">media-type</a> 4383 </pre><p id="rfc.section.D.5.8.p.3">Media types are defined in <a href="#media.types" title="Media Types">Appendix D.1.3</a>. An example of the field is 4384 </p> 4385 <div id="rfc.figure.u.64"></div><pre class="text"> Content-Type: text/html; charset=ISO-8859-4 4386 </pre><p id="rfc.section.D.5.8.p.5">Further discussion of Content-Type is provided in <a href="#representation.data" title="Representation Data">Appendix D.3.2</a>. 4387 </p> 4388 <h2 id="rfc.section.D.6"><a href="#rfc.section.D.6">D.6</a> <a id="IANA.considerations3" href="#IANA.considerations3">IANA Considerations</a></h2> 4389 <h3 id="rfc.section.D.6.1"><a href="#rfc.section.D.6.1">D.6.1</a> <a id="content.coding.registration" href="#content.coding.registration">Content Coding Registry</a></h3> 4390 <p id="rfc.section.D.6.1.p.1">The registration procedure for HTTP Content Codings is now defined by <a href="#content.coding.registry" title="Content Coding Registry">Appendix D.1.2.1</a> of this document. 4391 </p> 4392 <p id="rfc.section.D.6.1.p.2">The HTTP Content Codings Registry located at <<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>> shall be updated with the registration below: 4393 </p> 4394 <div id="rfc.table.4"> 4395 <div id="iana.content.coding.registration.table"></div> 4396 <table class="tt full left" cellpadding="3" cellspacing="0"> 4397 <thead> 4398 <tr> 4399 <th>Name</th> 4400 <th>Description</th> 4401 <th>Reference</th> 4402 </tr> 4403 </thead> 4404 <tbody> 4405 <tr> 4406 <td class="left">compress</td> 4407 <td class="left">UNIX "compress" program method</td> 4408 <td class="left"> <a href="p1-messaging.html#compress.coding" title="Compress Coding">Section 4.2.1</a> of <a href="#Part1" id="rfc.xref.Part1.56"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> 4409 </td> 4410 </tr> 4411 <tr> 4412 <td class="left">deflate</td> 4413 <td class="left">"deflate" compression mechanism (<a href="#RFC1951" id="rfc.xref.RFC1951.1"><cite title="DEFLATE Compressed Data Format Specification version 1.3">[RFC1951]</cite></a>) used inside the "zlib" data format (<a href="#RFC1950" id="rfc.xref.RFC1950.1"><cite title="ZLIB Compressed Data Format Specification version 3.3">[RFC1950]</cite></a>) 4414 </td> 4415 <td class="left"> <a href="p1-messaging.html#deflate.coding" title="Deflate Coding">Section 4.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.57"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> 4416 </td> 4417 </tr> 4418 <tr> 4419 <td class="left">gzip</td> 4420 <td class="left">Same as GNU zip <a href="#RFC1952" id="rfc.xref.RFC1952.1"><cite title="GZIP file format specification version 4.3">[RFC1952]</cite></a></td> 4421 <td class="left"> <a href="p1-messaging.html#gzip.coding" title="Gzip Coding">Section 4.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.58"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> 4422 </td> 4423 </tr> 4424 <tr> 4425 <td class="left">identity</td> 4426 <td class="left">reserved (synonym for "no encoding" in Accept-Encoding header field)</td> 4427 <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.5" title="Accept-Encoding">Appendix D.5.3</a> 4428 </td> 4429 </tr> 4430 </tbody> 4431 </table> 4432 </div> 4433 <h2 id="rfc.section.D.7"><a href="#rfc.section.D.7">D.7</a> <a id="security.considerations3" href="#security.considerations3">Security Considerations</a></h2> 4434 <p id="rfc.section.D.7.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1 4435 as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does 4436 make some suggestions for reducing security risks. 4437 </p> 4438 <h3 id="rfc.section.D.7.1"><a href="#rfc.section.D.7.1">D.7.1</a> <a id="privacy.issues.connected.to.accept.header.fields" href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></h3> 4439 <p id="rfc.section.D.7.1.p.1">Accept header fields can reveal information about the user to all servers which are accessed. The Accept-Language header field 4440 in particular can reveal information the user would consider to be of a private nature, because the understanding of particular 4441 languages is often strongly correlated to the membership of a particular ethnic group. User agents which offer the option 4442 to configure the contents of an Accept-Language header field to be sent in every request are strongly encouraged to let the 4443 configuration process include a message which makes the user aware of the loss of privacy involved. 4444 </p> 4445 <p id="rfc.section.D.7.1.p.2">An approach that limits the loss of privacy would be for a user agent to omit the sending of Accept-Language header fields 4446 by default, and to ask the user whether or not to start sending Accept-Language header fields to a server if it detects, by 4447 looking for any Vary header fields generated by the server, that such sending could improve the quality of service. 4448 </p> 4449 <p id="rfc.section.D.7.1.p.3">Elaborate user-customized accept header fields sent in every request, in particular if these include quality values, can be 4450 used by servers as relatively reliable and long-lived user identifiers. Such user identifiers would allow content providers 4451 to do click-trail tracking, and would allow collaborating content providers to match cross-server click-trails or form submissions 4452 of individual users. Note that for many users not behind a proxy, the network address of the host running the user agent will 4453 also serve as a long-lived user identifier. In environments where proxies are used to enhance privacy, user agents ought to 4454 be conservative in offering accept header configuration options to end users. As an extreme privacy measure, proxies could 4455 filter the accept header fields in relayed requests. General purpose user agents which provide a high degree of header configurability <em class="bcp14">SHOULD</em> warn users about the loss of privacy which can be involved. 4456 </p> 4457 <h2 id="rfc.section.D.8"><a href="#rfc.section.D.8">D.8</a> <a id="differences.between.http.and.mime" href="#differences.between.http.and.mime">Differences between HTTP and MIME</a></h2> 4458 <p id="rfc.section.D.8.p.1">HTTP/1.1 uses many of the constructs defined for Internet Mail (<a href="#RFC5322" id="rfc.xref.RFC5322.5"><cite title="Internet Message Format">[RFC5322]</cite></a>) and the Multipurpose Internet Mail Extensions (MIME <a href="#RFC2045" id="rfc.xref.RFC2045.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>) to allow a message body to be transmitted in an open variety of representations and with extensible mechanisms. However, 4459 RFC 2045 discusses mail, and HTTP has a few features that are different from those described in MIME. These differences were 4460 carefully chosen to optimize performance over binary connections, to allow greater freedom in the use of new media types, 4461 to make date comparisons easier, and to acknowledge the practice of some early HTTP servers and clients. 4462 </p> 4463 <p id="rfc.section.D.8.p.2">This appendix describes specific areas where HTTP differs from MIME. Proxies and gateways to strict MIME environments <em class="bcp14">SHOULD</em> be aware of these differences and provide the appropriate conversions where necessary. Proxies and gateways from MIME environments 4464 to HTTP also need to be aware of the differences because some conversions might be required. 4465 </p> 4466 <div id="rfc.iref.m.10"></div> 4467 <div id="rfc.iref.h.20"></div> 4468 <h3 id="rfc.section.D.8.1"><a href="#rfc.section.D.8.1">D.8.1</a> <a id="mime-version" href="#mime-version">MIME-Version</a></h3> 4469 <p id="rfc.section.D.8.1.p.1">HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages <em class="bcp14">MAY</em> include a single MIME-Version header field to indicate what version of the MIME protocol was used to construct the message. 4470 Use of the MIME-Version header field indicates that the message is in full conformance with the MIME protocol (as defined 4471 in <a href="#RFC2045" id="rfc.xref.RFC2045.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>). Proxies/gateways are responsible for ensuring full conformance (where possible) when exporting HTTP messages to strict 4472 MIME environments. 4473 </p> 4474 <div id="rfc.figure.u.65"></div><pre class="inline"><span id="rfc.iref.g.59"></span> <a href="#mime-version" class="smpl">MIME-Version</a> = 1*<a href="#notation" class="smpl">DIGIT</a> "." 1*<a href="#notation" class="smpl">DIGIT</a> 4475 </pre><p id="rfc.section.D.8.1.p.3">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 4476 document and not the MIME specification. 4477 </p> 4478 <h3 id="rfc.section.D.8.2"><a href="#rfc.section.D.8.2">D.8.2</a> <a id="conversion.to.canonical.form" href="#conversion.to.canonical.form">Conversion to Canonical Form</a></h3> 4479 <p id="rfc.section.D.8.2.p.1">MIME requires that an Internet mail body-part be converted to canonical form prior to being transferred, as described in <a href="http://tools.ietf.org/html/rfc2049#section-4">Section 4</a> of <a href="#RFC2049" id="rfc.xref.RFC2049.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples">[RFC2049]</cite></a>. <a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Appendix D.1.3.1</a> of this document describes the forms allowed for subtypes of the "text" media type when transmitted over HTTP. <a href="#RFC2046" id="rfc.xref.RFC2046.4"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> requires that content with a type of "text" represent line breaks as CRLF and forbids the use of CR or LF outside of line 4480 break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a line break within text content when a message is transmitted 4481 over HTTP. 4482 </p> 4483 <p id="rfc.section.D.8.2.p.2">Where it is possible, a proxy or gateway from HTTP to a strict MIME environment <em class="bcp14">SHOULD</em> translate all line breaks within the text media types described in <a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Appendix D.1.3.1</a> of this document to the RFC 2049 canonical form of CRLF. Note, however, that this might be complicated by the presence of 4484 a Content-Encoding and by the fact that HTTP allows the use of some character encodings which do not use octets 13 and 10 4485 to represent CR and LF, respectively, as is the case for some multi-byte character encodings. 4486 </p> 4487 <p id="rfc.section.D.8.2.p.3">Conversion will break any cryptographic checksums applied to the original content unless the original content is already in 4488 canonical form. Therefore, the canonical form is recommended for any content that uses such checksums in HTTP. 4489 </p> 4490 <h3 id="rfc.section.D.8.3"><a href="#rfc.section.D.8.3">D.8.3</a> <a id="conversion.of.date.formats" href="#conversion.of.date.formats">Conversion of Date Formats</a></h3> 4491 <p id="rfc.section.D.8.3.p.1">HTTP/1.1 uses a restricted set of date formats (<a href="#http.date" title="Date/Time Formats">Section 6.1</a>) to simplify the process of date comparison. Proxies and gateways from other protocols <em class="bcp14">SHOULD</em> ensure that any Date header field present in a message conforms to one of the HTTP/1.1 formats and rewrite the date if necessary. 4492 </p> 4493 <h3 id="rfc.section.D.8.4"><a href="#rfc.section.D.8.4">D.8.4</a> <a id="introduction.of.content-encoding" href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></h3> 4494 <p id="rfc.section.D.8.4.p.1">MIME does not include any concept equivalent to HTTP/1.1's Content-Encoding header field. Since this acts as a modifier on 4495 the media type, proxies and gateways from HTTP to MIME-compliant protocols <em class="bcp14">MUST</em> either change the value of the Content-Type header field or decode the representation before forwarding the message. (Some 4496 experimental applications of Content-Type for Internet mail have used a media-type parameter of ";conversions=<content-coding>" 4497 to perform a function equivalent to Content-Encoding. However, this parameter is not part of the MIME standards). 4498 </p> 4499 <div id="rfc.iref.c.11"></div> 4500 <div id="rfc.iref.h.21"></div> 4501 <h3 id="rfc.section.D.8.5"><a href="#rfc.section.D.8.5">D.8.5</a> <a id="no.content-transfer-encoding" href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></h3> 4502 <p id="rfc.section.D.8.5.p.1">HTTP does not use the Content-Transfer-Encoding field of MIME. Proxies and gateways from MIME-compliant protocols to HTTP <em class="bcp14">MUST</em> remove any Content-Transfer-Encoding prior to delivering the response message to an HTTP client. 4503 </p> 4504 <p id="rfc.section.D.8.5.p.2">Proxies and gateways from HTTP to MIME-compliant protocols are responsible for ensuring that the message is in the correct 4505 format and encoding for safe transport on that protocol, where "safe transport" is defined by the limitations of the protocol 4506 being used. Such a proxy or gateway <em class="bcp14">SHOULD</em> label the data with an appropriate Content-Transfer-Encoding if doing so will improve the likelihood of safe transport over 4507 the destination protocol. 4508 </p> 4509 <h3 id="rfc.section.D.8.6"><a href="#rfc.section.D.8.6">D.8.6</a> <a id="introduction.of.transfer-encoding" href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></h3> 4510 <p id="rfc.section.D.8.6.p.1">HTTP/1.1 introduces the Transfer-Encoding header field (<a href="p1-messaging.html#header.transfer-encoding" title="Transfer-Encoding">Section 3.3.1</a> of <a href="#Part1" id="rfc.xref.Part1.59"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). Proxies/gateways <em class="bcp14">MUST</em> remove any transfer-coding prior to forwarding a message via a MIME-compliant protocol. 4511 </p> 4512 <h3 id="rfc.section.D.8.7"><a href="#rfc.section.D.8.7">D.8.7</a> <a id="mhtml.line.length" href="#mhtml.line.length">MHTML and Line Length Limitations</a></h3> 4513 <p id="rfc.section.D.8.7.p.1">HTTP implementations which share code with MHTML <a href="#RFC2557" id="rfc.xref.RFC2557.2"><cite title="MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)">[RFC2557]</cite></a> implementations need to be aware of MIME line length limitations. Since HTTP does not have this limitation, HTTP does not 4514 fold long lines. MHTML messages being transported by HTTP follow all conventions of MHTML, including line length limitations 4515 and folding, canonicalization, etc., since HTTP transports all message-bodies as payload (see <a href="#multipart.types" title="Multipart Types">Appendix D.1.3.2</a>) and does not interpret the content or any MIME header lines that might be contained therein. 4516 </p> 4517 <h2 id="rfc.section.D.9"><a href="#rfc.section.D.9">D.9</a> <a id="additional.features" href="#additional.features">Additional Features</a></h2> 4518 <p id="rfc.section.D.9.p.1"> <a href="#RFC1945" id="rfc.xref.RFC1945.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.0">[RFC1945]</cite></a> and <a href="#RFC2068" id="rfc.xref.RFC2068.3"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> document protocol elements used by some existing HTTP implementations, but not consistently and correctly across most HTTP/1.1 4519 applications. Implementors are advised to be aware of these features, but cannot rely upon their presence in, or interoperability 4520 with, other HTTP/1.1 applications. Some of these describe proposed experimental features, and some describe features that 4521 experimental deployment found lacking that are now addressed in the base HTTP/1.1 specification. 4522 </p> 4523 <p id="rfc.section.D.9.p.2">A number of other header fields, such as Content-Disposition and Title, from SMTP and MIME are also often implemented (see <a href="#RFC6266" id="rfc.xref.RFC6266.1"><cite title="Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP)">[RFC6266]</cite></a> and <a href="#RFC2076" id="rfc.xref.RFC2076.1"><cite title="Common Internet Message Headers">[RFC2076]</cite></a>). 4524 </p> 4525 <h2 id="rfc.section.D.10"><a href="#rfc.section.D.10">D.10</a> <a id="changes.from.rfc.2616-3" href="#changes.from.rfc.2616-3">Changes from RFC 2616</a></h2> 4526 <p id="rfc.section.D.10.p.1">Clarify contexts that charset is used in. (<a href="#character.sets" title="Character Encodings (charset)">Appendix D.1.1</a>) 4527 </p> 4528 <p id="rfc.section.D.10.p.2">Registration of Content Codings now requires IETF Review (<a href="#content.coding.registry" title="Content Coding Registry">Appendix D.1.2.1</a>) 4529 </p> 4530 <p id="rfc.section.D.10.p.3">Remove the default character encoding for text media types; the default now is whatever the media type definition says. (<a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Appendix D.1.3.1</a>) 4531 </p> 4532 <p id="rfc.section.D.10.p.4">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section 7</a>) 4533 </p> 4534 <p id="rfc.section.D.10.p.5">Remove definition of Content-MD5 header field because it was inconsistently implemented with respect to partial responses, 4535 and also because of known deficiencies in the hash algorithm itself (see <a href="#RFC6151" id="rfc.xref.RFC6151.1"><cite title="Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithms">[RFC6151]</cite></a> for details). (<a href="#header.field.definitions" title="Header Field Definitions">Section 7</a>) 4536 </p> 4537 <p id="rfc.section.D.10.p.6">Remove ISO-8859-1 special-casing in Accept-Charset. (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.4" title="Accept-Charset">Appendix D.5.2</a>) 4538 </p> 4539 <p id="rfc.section.D.10.p.7">Remove base URI setting semantics for Content-Location due to poor implementation support, which was caused by too many broken 4540 servers emitting bogus Content-Location header fields, and also the potentially undesirable effect of potentially breaking 4541 relative links in content-negotiated resources. (<a href="#header.content-location" id="rfc.xref.header.content-location.5" title="Content-Location">Appendix D.5.7</a>) 4542 </p> 4543 <p id="rfc.section.D.10.p.8">Remove reference to non-existant identity transfer-coding value tokens. (<a href="#no.content-transfer-encoding" id="rfc.xref.no.content-transfer-encoding.1" title="No Content-Transfer-Encoding">Appendix D.8.5</a>) 4544 </p> 4545 <p id="rfc.section.D.10.p.9">Remove discussion of Content-Disposition header field, it is now defined by <a href="#RFC6266" id="rfc.xref.RFC6266.2"><cite title="Use of the Content-Disposition Header Field in the Hypertext Transfer Protocol (HTTP)">[RFC6266]</cite></a>. (<a href="#additional.features" title="Additional Features">Appendix D.9</a>) 4546 </p> 4547 <h2 id="rfc.section.D.11"><a href="#rfc.section.D.11">D.11</a> <a id="change.log3" href="#change.log3">Change Log (to be removed by RFC Editor before publication)</a></h2> 4548 <h3 id="rfc.section.D.11.1"><a href="#rfc.section.D.11.1">D.11.1</a> Since RFC 2616 4549 </h3> 4550 <p id="rfc.section.D.11.1.p.1">Extracted relevant partitions from <a href="#RFC2616" id="rfc.xref.RFC2616.5"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>. 4551 </p> 4552 <h3 id="rfc.section.D.11.2"><a href="#rfc.section.D.11.2">D.11.2</a> Since draft-ietf-httpbis-p3-payload-00 4553 </h3> 4554 <p id="rfc.section.D.11.2.p.1">Closed issues: </p> 4555 <ul> 4556 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/8">http://tools.ietf.org/wg/httpbis/trac/ticket/8</a>>: "Media Type Registrations" (<<a href="http://purl.org/NET/http-errata#media-reg">http://purl.org/NET/http-errata#media-reg</a>>) 4557 </li> 4558 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/14">http://tools.ietf.org/wg/httpbis/trac/ticket/14</a>>: "Clarification regarding quoting of charset values" (<<a href="http://purl.org/NET/http-errata#charactersets">http://purl.org/NET/http-errata#charactersets</a>>) 4559 </li> 4560 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/16">http://tools.ietf.org/wg/httpbis/trac/ticket/16</a>>: "Remove 'identity' token references" (<<a href="http://purl.org/NET/http-errata#identity">http://purl.org/NET/http-errata#identity</a>>) 4561 </li> 4562 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/25">http://tools.ietf.org/wg/httpbis/trac/ticket/25</a>>: "Accept-Encoding BNF" 4563 </li> 4564 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/35">http://tools.ietf.org/wg/httpbis/trac/ticket/35</a>>: "Normative and Informative references" 4565 </li> 4566 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/46">http://tools.ietf.org/wg/httpbis/trac/ticket/46</a>>: "RFC1700 references" 4567 </li> 4568 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/55">http://tools.ietf.org/wg/httpbis/trac/ticket/55</a>>: "Updating to RFC4288" 4569 </li> 4570 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/65">http://tools.ietf.org/wg/httpbis/trac/ticket/65</a>>: "Informative references" 4571 </li> 4572 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/66">http://tools.ietf.org/wg/httpbis/trac/ticket/66</a>>: "ISO-8859-1 Reference" 4573 </li> 4574 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/68">http://tools.ietf.org/wg/httpbis/trac/ticket/68</a>>: "Encoding References Normative" 4575 </li> 4576 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/86">http://tools.ietf.org/wg/httpbis/trac/ticket/86</a>>: "Normative up-to-date references" 4577 </li> 4578 </ul> 4579 <h3 id="rfc.section.D.11.3"><a href="#rfc.section.D.11.3">D.11.3</a> Since draft-ietf-httpbis-p3-payload-01 4580 </h3> 4581 <p id="rfc.section.D.11.3.p.1">Ongoing work on ABNF conversion (<<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>>): 4582 </p> 4583 <ul> 4584 <li>Add explicit references to BNF syntax and rules imported from other parts of the specification.</li> 4585 </ul> 4586 <h3 id="rfc.section.D.11.4"><a href="#rfc.section.D.11.4">D.11.4</a> <a id="changes.3.since.02" href="#changes.3.since.02">Since draft-ietf-httpbis-p3-payload-02</a></h3> 4587 <p id="rfc.section.D.11.4.p.1">Closed issues: </p> 4588 <ul> 4589 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/67">http://tools.ietf.org/wg/httpbis/trac/ticket/67</a>>: "Quoting Charsets" 4590 </li> 4591 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/105">http://tools.ietf.org/wg/httpbis/trac/ticket/105</a>>: "Classification for Allow header" 4592 </li> 4593 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/115">http://tools.ietf.org/wg/httpbis/trac/ticket/115</a>>: "missing default for qvalue in description of Accept-Encoding" 4594 </li> 4595 </ul> 4596 <p id="rfc.section.D.11.4.p.2">Ongoing work on IANA Message Header Field Registration (<<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/40">http://tools.ietf.org/wg/httpbis/trac/ticket/40</a>>): 4597 </p> 4598 <ul> 4599 <li>Reference RFC 3984, and update header field registrations for headers defined in this document.</li> 4600 </ul> 4601 <h3 id="rfc.section.D.11.5"><a href="#rfc.section.D.11.5">D.11.5</a> <a id="changes.3.since.03" href="#changes.3.since.03">Since draft-ietf-httpbis-p3-payload-03</a></h3> 4602 <p id="rfc.section.D.11.5.p.1">Closed issues: </p> 4603 <ul> 4604 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/67">http://tools.ietf.org/wg/httpbis/trac/ticket/67</a>>: "Quoting Charsets" 4605 </li> 4606 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/113">http://tools.ietf.org/wg/httpbis/trac/ticket/113</a>>: "language tag matching (Accept-Language) vs RFC4647" 4607 </li> 4608 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/121">http://tools.ietf.org/wg/httpbis/trac/ticket/121</a>>: "RFC 1806 has been replaced by RFC2183" 4609 </li> 4610 </ul> 4611 <p id="rfc.section.D.11.5.p.2">Other changes: </p> 4612 <ul> 4613 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/68">http://tools.ietf.org/wg/httpbis/trac/ticket/68</a>>: "Encoding References Normative" — rephrase the annotation and reference BCP97. 4614 </li> 4615 </ul> 4616 <h3 id="rfc.section.D.11.6"><a href="#rfc.section.D.11.6">D.11.6</a> <a id="changes.3.since.04" href="#changes.3.since.04">Since draft-ietf-httpbis-p3-payload-04</a></h3> 4617 <p id="rfc.section.D.11.6.p.1">Closed issues: </p> 4618 <ul> 4619 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/132">http://tools.ietf.org/wg/httpbis/trac/ticket/132</a>>: "RFC 2822 is updated by RFC 5322" 4620 </li> 4621 </ul> 4622 <p id="rfc.section.D.11.6.p.2">Ongoing work on ABNF conversion (<<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>>): 4623 </p> 4624 <ul> 4625 <li>Use "/" instead of "|" for alternatives.</li> 4626 <li>Introduce new ABNF rules for "bad" whitespace ("BWS"), optional whitespace ("OWS") and required whitespace ("RWS").</li> 4627 <li>Rewrite ABNFs to spell out whitespace rules, factor out header field value format definitions.</li> 4628 </ul> 4629 <h3 id="rfc.section.D.11.7"><a href="#rfc.section.D.11.7">D.11.7</a> <a id="changes.3.since.05" href="#changes.3.since.05">Since draft-ietf-httpbis-p3-payload-05</a></h3> 4630 <p id="rfc.section.D.11.7.p.1">Closed issues: </p> 4631 <ul> 4632 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/118">http://tools.ietf.org/wg/httpbis/trac/ticket/118</a>>: "Join "Differences Between HTTP Entities and RFC 2045 Entities"?" 4633 </li> 4634 </ul> 4635 <p id="rfc.section.D.11.7.p.2">Final work on ABNF conversion (<<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>>): 4636 </p> 4637 <ul> 4638 <li>Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.</li> 4639 </ul> 4640 <p id="rfc.section.D.11.7.p.3">Other changes: </p> 4641 <ul> 4642 <li>Move definition of quality values into Part 1.</li> 4643 </ul> 4644 <h3 id="rfc.section.D.11.8"><a href="#rfc.section.D.11.8">D.11.8</a> <a id="changes.3.since.06" href="#changes.3.since.06">Since draft-ietf-httpbis-p3-payload-06</a></h3> 4645 <p id="rfc.section.D.11.8.p.1">Closed issues: </p> 4646 <ul> 4647 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/80">http://tools.ietf.org/wg/httpbis/trac/ticket/80</a>>: "Content-Location isn't special" 4648 </li> 4649 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/155">http://tools.ietf.org/wg/httpbis/trac/ticket/155</a>>: "Content Sniffing" 4650 </li> 4651 </ul> 4652 <h3 id="rfc.section.D.11.9"><a href="#rfc.section.D.11.9">D.11.9</a> <a id="changes.3.since.07" href="#changes.3.since.07">Since draft-ietf-httpbis-p3-payload-07</a></h3> 4653 <p id="rfc.section.D.11.9.p.1">Closed issues: </p> 4654 <ul> 4655 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/13">http://tools.ietf.org/wg/httpbis/trac/ticket/13</a>>: "Updated reference for language tags" 4656 </li> 4657 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/110">http://tools.ietf.org/wg/httpbis/trac/ticket/110</a>>: "Clarify rules for determining what entities a response carries" 4658 </li> 4659 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/154">http://tools.ietf.org/wg/httpbis/trac/ticket/154</a>>: "Content-Location base-setting problems" 4660 </li> 4661 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/155">http://tools.ietf.org/wg/httpbis/trac/ticket/155</a>>: "Content Sniffing" 4662 </li> 4663 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/188">http://tools.ietf.org/wg/httpbis/trac/ticket/188</a>>: "pick IANA policy (RFC5226) for Transfer Coding / Content Coding" 4664 </li> 4665 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/189">http://tools.ietf.org/wg/httpbis/trac/ticket/189</a>>: "move definitions of gzip/deflate/compress to part 1" 4666 </li> 4667 </ul> 4668 <p id="rfc.section.D.11.9.p.2">Partly resolved issues: </p> 4669 <ul> 4670 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/148">http://tools.ietf.org/wg/httpbis/trac/ticket/148</a>>: "update IANA requirements wrt Transfer-Coding values" (add the IANA Considerations subsection) 4671 </li> 4672 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/149">http://tools.ietf.org/wg/httpbis/trac/ticket/149</a>>: "update IANA requirements wrt Content-Coding values" (add the IANA Considerations subsection) 4673 </li> 4674 </ul> 4675 <h3 id="rfc.section.D.11.10"><a href="#rfc.section.D.11.10">D.11.10</a> <a id="changes.3.since.08" href="#changes.3.since.08">Since draft-ietf-httpbis-p3-payload-08</a></h3> 4676 <p id="rfc.section.D.11.10.p.1">Closed issues: </p> 4677 <ul> 4678 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/81">http://tools.ietf.org/wg/httpbis/trac/ticket/81</a>>: "Content Negotiation for media types" 4679 </li> 4680 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/181">http://tools.ietf.org/wg/httpbis/trac/ticket/181</a>>: "Accept-Language: which RFC4647 filtering?" 4681 </li> 4682 </ul> 4683 <h3 id="rfc.section.D.11.11"><a href="#rfc.section.D.11.11">D.11.11</a> <a id="changes.3.since.09" href="#changes.3.since.09">Since draft-ietf-httpbis-p3-payload-09</a></h3> 4684 <p id="rfc.section.D.11.11.p.1">Closed issues: </p> 4685 <ul> 4686 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/122">http://tools.ietf.org/wg/httpbis/trac/ticket/122</a>>: "MIME-Version not listed in P1, general header fields" 4687 </li> 4688 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/143">http://tools.ietf.org/wg/httpbis/trac/ticket/143</a>>: "IANA registry for content/transfer encodings" 4689 </li> 4690 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/155">http://tools.ietf.org/wg/httpbis/trac/ticket/155</a>>: "Content Sniffing" 4691 </li> 4692 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/200">http://tools.ietf.org/wg/httpbis/trac/ticket/200</a>>: "use of term "word" when talking about header structure" 4693 </li> 4694 </ul> 4695 <p id="rfc.section.D.11.11.p.2">Partly resolved issues: </p> 4696 <ul> 4697 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/196">http://tools.ietf.org/wg/httpbis/trac/ticket/196</a>>: "Term for the requested resource's URI" 4698 </li> 4699 </ul> 4700 <h3 id="rfc.section.D.11.12"><a href="#rfc.section.D.11.12">D.11.12</a> <a id="changes.3.since.10" href="#changes.3.since.10">Since draft-ietf-httpbis-p3-payload-10</a></h3> 4701 <p id="rfc.section.D.11.12.p.1">Closed issues: </p> 4702 <ul> 4703 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/69">http://tools.ietf.org/wg/httpbis/trac/ticket/69</a>>: "Clarify 'Requested Variant'" 4704 </li> 4705 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/80">http://tools.ietf.org/wg/httpbis/trac/ticket/80</a>>: "Content-Location isn't special" 4706 </li> 4707 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/90">http://tools.ietf.org/wg/httpbis/trac/ticket/90</a>>: "Delimiting messages with multipart/byteranges" 4708 </li> 4709 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/109">http://tools.ietf.org/wg/httpbis/trac/ticket/109</a>>: "Clarify entity / representation / variant terminology" 4710 </li> 4711 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/136">http://tools.ietf.org/wg/httpbis/trac/ticket/136</a>>: "confusing req. language for Content-Location" 4712 </li> 4713 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/167">http://tools.ietf.org/wg/httpbis/trac/ticket/167</a>>: "Content-Location on 304 responses" 4714 </li> 4715 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/183">http://tools.ietf.org/wg/httpbis/trac/ticket/183</a>>: "'requested resource' in content-encoding definition" 4716 </li> 4717 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/220">http://tools.ietf.org/wg/httpbis/trac/ticket/220</a>>: "consider removing the 'changes from 2068' sections" 4718 </li> 4719 </ul> 4720 <p id="rfc.section.D.11.12.p.2">Partly resolved issues: </p> 4721 <ul> 4722 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/178">http://tools.ietf.org/wg/httpbis/trac/ticket/178</a>>: "Content-MD5 and partial responses" 4723 </li> 4724 </ul> 4725 <h3 id="rfc.section.D.11.13"><a href="#rfc.section.D.11.13">D.11.13</a> <a id="changes.3.since.11" href="#changes.3.since.11">Since draft-ietf-httpbis-p3-payload-11</a></h3> 4726 <p id="rfc.section.D.11.13.p.1">Closed issues: </p> 4727 <ul> 4728 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/123">http://tools.ietf.org/wg/httpbis/trac/ticket/123</a>>: "Factor out Content-Disposition" 4729 </li> 4730 </ul> 4731 <h3 id="rfc.section.D.11.14"><a href="#rfc.section.D.11.14">D.11.14</a> <a id="changes.3.since.12" href="#changes.3.since.12">Since draft-ietf-httpbis-p3-payload-12</a></h3> 4732 <p id="rfc.section.D.11.14.p.1">Closed issues: </p> 4733 <ul> 4734 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/224">http://tools.ietf.org/wg/httpbis/trac/ticket/224</a>>: "Header Classification" 4735 </li> 4736 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/276">http://tools.ietf.org/wg/httpbis/trac/ticket/276</a>>: "untangle ABNFs for header fields" 4737 </li> 4738 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/277">http://tools.ietf.org/wg/httpbis/trac/ticket/277</a>>: "potentially misleading MAY in media-type def" 4739 </li> 4740 </ul> 4741 <h3 id="rfc.section.D.11.15"><a href="#rfc.section.D.11.15">D.11.15</a> <a id="changes.3.since.13" href="#changes.3.since.13">Since draft-ietf-httpbis-p3-payload-13</a></h3> 4742 <p id="rfc.section.D.11.15.p.1">Closed issues: </p> 4743 <ul> 4744 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/20">http://tools.ietf.org/wg/httpbis/trac/ticket/20</a>>: "Default charsets for text media types" 4745 </li> 4746 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/178">http://tools.ietf.org/wg/httpbis/trac/ticket/178</a>>: "Content-MD5 and partial responses" 4747 </li> 4748 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/276">http://tools.ietf.org/wg/httpbis/trac/ticket/276</a>>: "untangle ABNFs for header fields" 4749 </li> 4750 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/281">http://tools.ietf.org/wg/httpbis/trac/ticket/281</a>>: "confusing undefined parameter in media range example" 4751 </li> 4752 </ul> 4753 <h3 id="rfc.section.D.11.16"><a href="#rfc.section.D.11.16">D.11.16</a> <a id="changes.3.since.14" href="#changes.3.since.14">Since draft-ietf-httpbis-p3-payload-14</a></h3> 4754 <p id="rfc.section.D.11.16.p.1">None.</p> 4755 <h3 id="rfc.section.D.11.17"><a href="#rfc.section.D.11.17">D.11.17</a> <a id="changes.3.since.15" href="#changes.3.since.15">Since draft-ietf-httpbis-p3-payload-15</a></h3> 4756 <p id="rfc.section.D.11.17.p.1">Closed issues: </p> 4757 <ul> 4758 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/285">http://tools.ietf.org/wg/httpbis/trac/ticket/285</a>>: "Strength of requirements on Accept re: 406" 4759 </li> 4760 </ul> 4761 <h3 id="rfc.section.D.11.18"><a href="#rfc.section.D.11.18">D.11.18</a> <a id="changes.3.since.16" href="#changes.3.since.16">Since draft-ietf-httpbis-p3-payload-16</a></h3> 4762 <p id="rfc.section.D.11.18.p.1">Closed issues: </p> 4763 <ul> 4764 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/186">http://tools.ietf.org/wg/httpbis/trac/ticket/186</a>>: "Document HTTP's error-handling philosophy" 4765 </li> 4766 </ul> 4767 <h3 id="rfc.section.D.11.19"><a href="#rfc.section.D.11.19">D.11.19</a> <a id="changes.3.since.17" href="#changes.3.since.17">Since draft-ietf-httpbis-p3-payload-17</a></h3> 4768 <p id="rfc.section.D.11.19.p.1">Closed issues: </p> 4769 <ul> 4770 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/323">http://tools.ietf.org/wg/httpbis/trac/ticket/323</a>>: "intended maturity level vs normative references" 4771 </li> 4772 </ul> 4773 <h3 id="rfc.section.D.11.20"><a href="#rfc.section.D.11.20">D.11.20</a> <a id="changes.3.since.18" href="#changes.3.since.18">Since draft-ietf-httpbis-p3-payload-18</a></h3> 4774 <p id="rfc.section.D.11.20.p.1">Closed issues: </p> 4775 <ul> 4776 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/330">http://tools.ietf.org/wg/httpbis/trac/ticket/330</a>>: "is ETag a representation header field?" 4777 </li> 4778 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/338">http://tools.ietf.org/wg/httpbis/trac/ticket/338</a>>: "Content-Location doesn't constrain the cardinality of representations" 4779 </li> 4780 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/346">http://tools.ietf.org/wg/httpbis/trac/ticket/346</a>>: "make IANA policy definitions consistent" 4781 </li> 4782 </ul> 4783 <h3 id="rfc.section.D.11.21"><a href="#rfc.section.D.11.21">D.11.21</a> <a id="changes.3.since.19" href="#changes.3.since.19">Since draft-ietf-httpbis-p3-payload-19</a></h3> 4784 <p id="rfc.section.D.11.21.p.1">None yet.</p> 3518 4785 <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1> 3519 4786 <p class="noprint"><a href="#rfc.index.1">1</a> <a href="#rfc.index.2">2</a> <a href="#rfc.index.3">3</a> <a href="#rfc.index.4">4</a> <a href="#rfc.index.5">5</a> <a href="#rfc.index.A">A</a> <a href="#rfc.index.C">C</a> <a href="#rfc.index.D">D</a> <a href="#rfc.index.E">E</a> <a href="#rfc.index.F">F</a> <a href="#rfc.index.G">G</a> <a href="#rfc.index.H">H</a> <a href="#rfc.index.I">I</a> <a href="#rfc.index.L">L</a> <a href="#rfc.index.M">M</a> <a href="#rfc.index.O">O</a> <a href="#rfc.index.P">P</a> <a href="#rfc.index.R">R</a> <a href="#rfc.index.S">S</a> <a href="#rfc.index.T">T</a> <a href="#rfc.index.U">U</a> … … 3574 4841 </li> 3575 4842 <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul> 4843 <li>Accept header field <a href="#rfc.xref.header.accept.1">3.2</a>, <a href="#rfc.xref.header.accept.2">8.3</a>, <a href="#rfc.xref.header.accept.3">D.1.3</a>, <a href="#rfc.xref.header.accept.4">D.4.1</a>, <a href="#rfc.iref.a.2"><b>D.5.1</b></a></li> 4844 <li>Accept-Charset header field <a href="#rfc.xref.header.accept-charset.1">3.2</a>, <a href="#rfc.xref.header.accept-charset.2">8.3</a>, <a href="#rfc.xref.header.accept-charset.3">D.4.1</a>, <a href="#rfc.iref.a.3"><b>D.5.2</b></a>, <a href="#rfc.xref.header.accept-charset.4">D.10</a></li> 4845 <li>Accept-Encoding header field <a href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a href="#rfc.xref.header.accept-encoding.2">8.3</a>, <a href="#rfc.xref.header.accept-encoding.3">D.1.2</a>, <a href="#rfc.xref.header.accept-encoding.4">D.4.1</a>, <a href="#rfc.iref.a.4"><b>D.5.3</b></a>, <a href="#rfc.xref.header.accept-encoding.5">D.6.1</a></li> 4846 <li>Accept-Language header field <a href="#rfc.xref.header.accept-language.1">3.2</a>, <a href="#rfc.xref.header.accept-language.2">8.3</a>, <a href="#rfc.xref.header.accept-language.3">D.4.1</a>, <a href="#rfc.iref.a.5"><b>D.5.4</b></a></li> 3576 4847 <li>Allow header field <a href="#rfc.xref.header.allow.1">2</a>, <a href="#rfc.xref.header.allow.2">3.3</a>, <a href="#rfc.iref.a.1"><b>7.1</b></a>, <a href="#rfc.xref.header.allow.3">8.3</a>, <a href="#rfc.xref.header.allow.4">A</a></li> 3577 4848 </ul> 3578 4849 </li> 3579 4850 <li><a id="rfc.index.C" href="#rfc.index.C"><b>C</b></a><ul> 4851 <li>Coding Format 4852 <ul> 4853 <li>compress <a href="#rfc.iref.c.4">D.1.2</a></li> 4854 <li>deflate <a href="#rfc.iref.c.5">D.1.2</a></li> 4855 <li>gzip <a href="#rfc.iref.c.6">D.1.2</a></li> 4856 </ul> 4857 </li> 4858 <li>compress (Coding Format) <a href="#rfc.iref.c.3">D.1.2</a></li> 3580 4859 <li>CONNECT method <a href="#rfc.iref.c.2"><b>2.3.8</b></a>, <a href="#rfc.xref.CONNECT.1">8.1</a>, <a href="#rfc.xref.CONNECT.2">A</a></li> 3581 4860 <li>content negotiation <a href="#rfc.iref.c.1">1.1</a></li> 4861 <li>Content-Encoding header field <a href="#rfc.xref.header.content-encoding.1">8.3</a>, <a href="#rfc.xref.header.content-encoding.2">D.1.2</a>, <a href="#rfc.xref.header.content-encoding.3">D.3.1</a>, <a href="#rfc.iref.c.7"><b>D.5.5</b></a>, <a href="#rfc.xref.header.content-encoding.4">D.5.5</a></li> 4862 <li>Content-Language header field <a href="#rfc.xref.header.content-language.1">8.3</a>, <a href="#rfc.xref.header.content-language.2">D.3.1</a>, <a href="#rfc.iref.c.8"><b>D.5.6</b></a></li> 4863 <li>Content-Location header field <a href="#rfc.xref.header.content-location.1">2.3.4</a>, <a href="#rfc.xref.header.content-location.2">7.5</a>, <a href="#rfc.xref.header.content-location.3">8.3</a>, <a href="#rfc.xref.header.content-location.4">D.3.1</a>, <a href="#rfc.iref.c.9"><b>D.5.7</b></a>, <a href="#rfc.xref.header.content-location.5">D.10</a></li> 4864 <li>Content-Transfer-Encoding header field <a href="#rfc.iref.c.11">D.8.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">D.10</a></li> 4865 <li>Content-Type header field <a href="#rfc.xref.header.content-type.1">3.1</a>, <a href="#rfc.xref.header.content-type.2">4</a>, <a href="#rfc.xref.header.content-type.3">8.3</a>, <a href="#rfc.xref.header.content-type.4">D.1.3</a>, <a href="#rfc.xref.header.content-type.5">D.3.1</a>, <a href="#rfc.iref.c.10"><b>D.5.8</b></a></li> 3582 4866 </ul> 3583 4867 </li> 3584 4868 <li><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul> 3585 4869 <li>Date header field <a href="#rfc.xref.header.date.1">3.3</a>, <a href="#rfc.iref.d.2"><b>7.2</b></a>, <a href="#rfc.xref.header.date.2">8.3</a></li> 4870 <li>deflate (Coding Format) <a href="#rfc.iref.d.3">D.1.2</a></li> 3586 4871 <li>DELETE method <a href="#rfc.iref.d.1"><b>2.3.6</b></a>, <a href="#rfc.xref.DELETE.1">8.1</a></li> 3587 4872 <li><em>draft-reschke-http-status-308</em> <a href="#rfc.xref.draft-reschke-http-status-308.1">4.5.7</a>, <a href="#draft-reschke-http-status-308"><b>11.2</b></a></li> … … 3605 4890 <li><tt>Grammar</tt> 3606 4891 <ul> 4892 <li><tt>Accept</tt> <a href="#rfc.iref.g.46"><b>D.5.1</b></a></li> 4893 <li><tt>Accept-Charset</tt> <a href="#rfc.iref.g.50"><b>D.5.2</b></a></li> 4894 <li><tt>Accept-Encoding</tt> <a href="#rfc.iref.g.51"><b>D.5.3</b></a></li> 4895 <li><tt>accept-ext</tt> <a href="#rfc.iref.g.49"><b>D.5.1</b></a></li> 4896 <li><tt>Accept-Language</tt> <a href="#rfc.iref.g.53"><b>D.5.4</b></a></li> 4897 <li><tt>accept-params</tt> <a href="#rfc.iref.g.48"><b>D.5.1</b></a></li> 3607 4898 <li><tt>Allow</tt> <a href="#rfc.iref.g.21"><b>7.1</b></a></li> 3608 4899 <li><tt>asctime-date</tt> <a href="#rfc.iref.g.18"><b>6.1</b></a></li> 4900 <li><tt>attribute</tt> <a href="#rfc.iref.g.43"><b>D.1.3</b></a></li> 4901 <li><tt>charset</tt> <a href="#rfc.iref.g.36"><b>D.1.1</b></a></li> 4902 <li><tt>codings</tt> <a href="#rfc.iref.g.52"><b>D.5.3</b></a></li> 4903 <li><tt>content-coding</tt> <a href="#rfc.iref.g.37"><b>D.1.2</b></a></li> 4904 <li><tt>Content-Encoding</tt> <a href="#rfc.iref.g.55"><b>D.5.5</b></a></li> 4905 <li><tt>Content-Language</tt> <a href="#rfc.iref.g.56"><b>D.5.6</b></a></li> 4906 <li><tt>Content-Location</tt> <a href="#rfc.iref.g.57"><b>D.5.7</b></a></li> 4907 <li><tt>Content-Type</tt> <a href="#rfc.iref.g.58"><b>D.5.8</b></a></li> 3609 4908 <li><tt>Date</tt> <a href="#rfc.iref.g.22"><b>7.2</b></a></li> 3610 4909 <li><tt>date1</tt> <a href="#rfc.iref.g.5"><b>6.1</b></a></li> … … 3622 4921 <li><tt>hour</tt> <a href="#rfc.iref.g.7"><b>6.1</b></a></li> 3623 4922 <li><tt>HTTP-date</tt> <a href="#rfc.iref.g.3"><b>6.1</b></a></li> 4923 <li><tt>language-range</tt> <a href="#rfc.iref.g.54"><b>D.5.4</b></a></li> 4924 <li><tt>language-tag</tt> <a href="#rfc.iref.g.45"><b>D.1.4</b></a></li> 3624 4925 <li><tt>Location</tt> <a href="#rfc.iref.g.29"><b>7.5</b></a></li> 3625 4926 <li><tt>Max-Forwards</tt> <a href="#rfc.iref.g.30"><b>7.6</b></a></li> 4927 <li><tt>media-range</tt> <a href="#rfc.iref.g.47"><b>D.5.1</b></a></li> 4928 <li><tt>media-type</tt> <a href="#rfc.iref.g.39"><b>D.1.3</b></a></li> 3626 4929 <li><tt>method</tt> <a href="#rfc.iref.g.1"><b>2</b></a></li> 4930 <li><tt>MIME-Version</tt> <a href="#rfc.iref.g.59"><b>D.8.1</b></a></li> 3627 4931 <li><tt>minute</tt> <a href="#rfc.iref.g.8"><b>6.1</b></a></li> 3628 4932 <li><tt>month</tt> <a href="#rfc.iref.g.13"><b>6.1</b></a></li> 3629 4933 <li><tt>obs-date</tt> <a href="#rfc.iref.g.16"><b>6.1</b></a></li> 4934 <li><tt>parameter</tt> <a href="#rfc.iref.g.42"><b>D.1.3</b></a></li> 3630 4935 <li><tt>product</tt> <a href="#rfc.iref.g.19"><b>6.2</b></a></li> 3631 4936 <li><tt>product-version</tt> <a href="#rfc.iref.g.20"><b>6.2</b></a></li> … … 3636 4941 <li><tt>second</tt> <a href="#rfc.iref.g.9"><b>6.1</b></a></li> 3637 4942 <li><tt>Server</tt> <a href="#rfc.iref.g.34"><b>7.9</b></a></li> 4943 <li><tt>subtype</tt> <a href="#rfc.iref.g.41"><b>D.1.3</b></a></li> 3638 4944 <li><tt>time-of-day</tt> <a href="#rfc.iref.g.6"><b>6.1</b></a></li> 4945 <li><tt>type</tt> <a href="#rfc.iref.g.40"><b>D.1.3</b></a></li> 3639 4946 <li><tt>User-Agent</tt> <a href="#rfc.iref.g.35"><b>7.10</b></a></li> 4947 <li><tt>value</tt> <a href="#rfc.iref.g.44"><b>D.1.3</b></a></li> 3640 4948 <li><tt>year</tt> <a href="#rfc.iref.g.14"><b>6.1</b></a></li> 3641 4949 </ul> 3642 4950 </li> 4951 <li>gzip (Coding Format) <a href="#rfc.iref.g.38">D.1.2</a></li> 3643 4952 </ul> 3644 4953 </li> … … 3647 4956 <li>Header Fields 3648 4957 <ul> 4958 <li>Accept <a href="#rfc.xref.header.accept.1">3.2</a>, <a href="#rfc.xref.header.accept.2">8.3</a>, <a href="#rfc.xref.header.accept.3">D.1.3</a>, <a href="#rfc.xref.header.accept.4">D.4.1</a>, <a href="#rfc.iref.h.12"><b>D.5.1</b></a></li> 4959 <li>Accept-Charset <a href="#rfc.xref.header.accept-charset.1">3.2</a>, <a href="#rfc.xref.header.accept-charset.2">8.3</a>, <a href="#rfc.xref.header.accept-charset.3">D.4.1</a>, <a href="#rfc.iref.h.13"><b>D.5.2</b></a>, <a href="#rfc.xref.header.accept-charset.4">D.10</a></li> 4960 <li>Accept-Encoding <a href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a href="#rfc.xref.header.accept-encoding.2">8.3</a>, <a href="#rfc.xref.header.accept-encoding.3">D.1.2</a>, <a href="#rfc.xref.header.accept-encoding.4">D.4.1</a>, <a href="#rfc.iref.h.14"><b>D.5.3</b></a>, <a href="#rfc.xref.header.accept-encoding.5">D.6.1</a></li> 4961 <li>Accept-Language <a href="#rfc.xref.header.accept-language.1">3.2</a>, <a href="#rfc.xref.header.accept-language.2">8.3</a>, <a href="#rfc.xref.header.accept-language.3">D.4.1</a>, <a href="#rfc.iref.h.15"><b>D.5.4</b></a></li> 3649 4962 <li>Allow <a href="#rfc.xref.header.allow.1">2</a>, <a href="#rfc.xref.header.allow.2">3.3</a>, <a href="#rfc.iref.h.2"><b>7.1</b></a>, <a href="#rfc.xref.header.allow.3">8.3</a>, <a href="#rfc.xref.header.allow.4">A</a></li> 4963 <li>Content-Encoding <a href="#rfc.xref.header.content-encoding.1">8.3</a>, <a href="#rfc.xref.header.content-encoding.2">D.1.2</a>, <a href="#rfc.xref.header.content-encoding.3">D.3.1</a>, <a href="#rfc.iref.h.16"><b>D.5.5</b></a>, <a href="#rfc.xref.header.content-encoding.4">D.5.5</a></li> 4964 <li>Content-Language <a href="#rfc.xref.header.content-language.1">8.3</a>, <a href="#rfc.xref.header.content-language.2">D.3.1</a>, <a href="#rfc.iref.h.17"><b>D.5.6</b></a></li> 4965 <li>Content-Location <a href="#rfc.xref.header.content-location.1">2.3.4</a>, <a href="#rfc.xref.header.content-location.2">7.5</a>, <a href="#rfc.xref.header.content-location.3">8.3</a>, <a href="#rfc.xref.header.content-location.4">D.3.1</a>, <a href="#rfc.iref.h.18"><b>D.5.7</b></a>, <a href="#rfc.xref.header.content-location.5">D.10</a></li> 4966 <li>Content-Transfer-Encoding <a href="#rfc.iref.h.21">D.8.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">D.10</a></li> 4967 <li>Content-Type <a href="#rfc.xref.header.content-type.1">3.1</a>, <a href="#rfc.xref.header.content-type.2">4</a>, <a href="#rfc.xref.header.content-type.3">8.3</a>, <a href="#rfc.xref.header.content-type.4">D.1.3</a>, <a href="#rfc.xref.header.content-type.5">D.3.1</a>, <a href="#rfc.iref.h.19"><b>D.5.8</b></a></li> 3650 4968 <li>Date <a href="#rfc.xref.header.date.1">3.3</a>, <a href="#rfc.iref.h.3"><b>7.2</b></a>, <a href="#rfc.xref.header.date.2">8.3</a></li> 3651 4969 <li>Expect <a href="#rfc.xref.header.expect.1">3.2</a>, <a href="#rfc.xref.header.expect.2">4.6.14</a>, <a href="#rfc.iref.h.4"><b>7.3</b></a>, <a href="#rfc.xref.header.expect.3">8.3</a>, <a href="#rfc.xref.header.expect.4">A</a></li> … … 3653 4971 <li>Location <a href="#rfc.xref.header.location.1">2.3.4</a>, <a href="#rfc.xref.header.location.2">3.3</a>, <a href="#rfc.xref.header.location.3">4.5</a>, <a href="#rfc.iref.h.6"><b>7.5</b></a>, <a href="#rfc.xref.header.location.4">8.3</a>, <a href="#rfc.xref.header.location.5">A</a></li> 3654 4972 <li>Max-Forwards <a href="#rfc.xref.header.max-forwards.1">2.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">2.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">3.2</a>, <a href="#rfc.iref.h.7"><b>7.6</b></a>, <a href="#rfc.xref.header.max-forwards.4">8.3</a>, <a href="#rfc.xref.header.max-forwards.5">A</a></li> 4973 <li>MIME-Version <a href="#rfc.xref.mime-version.1">8.3</a>, <a href="#rfc.iref.h.20"><b>D.8.1</b></a></li> 3655 4974 <li>Referer <a href="#rfc.xref.header.referer.1">3.2</a>, <a href="#rfc.iref.h.8"><b>7.7</b></a>, <a href="#rfc.xref.header.referer.2">8.3</a>, <a href="#rfc.xref.header.referer.3">A</a></li> 3656 4975 <li>Retry-After <a href="#rfc.xref.header.retry-after.1">3.3</a>, <a href="#rfc.xref.header.retry-after.2">4.7.4</a>, <a href="#rfc.iref.h.9"><b>7.8</b></a>, <a href="#rfc.xref.header.retry-after.3">8.3</a></li> 3657 4976 <li>Server <a href="#rfc.xref.header.server.1">3.3</a>, <a href="#rfc.iref.h.10"><b>7.9</b></a>, <a href="#rfc.xref.header.server.2">8.3</a>, <a href="#rfc.xref.header.server.3">9.1</a>, <a href="#rfc.xref.header.server.4">A</a></li> 3658 <li>User-Agent <a href="#rfc.xref.header.user-agent.1">3.2</a>, <a href="#rfc.iref.h.11"><b>7.10</b></a>, <a href="#rfc.xref.header.user-agent.2">8.3</a>, <a href="#rfc.xref.header.user-agent.3">9.1</a> </li>4977 <li>User-Agent <a href="#rfc.xref.header.user-agent.1">3.2</a>, <a href="#rfc.iref.h.11"><b>7.10</b></a>, <a href="#rfc.xref.header.user-agent.2">8.3</a>, <a href="#rfc.xref.header.user-agent.3">9.1</a>, <a href="#rfc.xref.header.user-agent.4">D.4.1</a></li> 3659 4978 </ul> 3660 4979 </li> … … 3683 5002 </ul> 3684 5003 </li> 5004 <li>MIME-Version header field <a href="#rfc.xref.mime-version.1">8.3</a>, <a href="#rfc.iref.m.10"><b>D.8.1</b></a></li> 3685 5005 </ul> 3686 5006 </li> … … 3690 5010 </li> 3691 5011 <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul> 3692 <li><em>Part1</em> <a href="#rfc.xref.Part1.1">1</a>, <a href="#rfc.xref.Part1.2">1.2</a>, <a href="#rfc.xref.Part1.3">1.3</a>, <a href="#rfc.xref.Part1.4">1.3.1</a>, <a href="#rfc.xref.Part1.5">1.3.1</a>, <a href="#rfc.xref.Part1.6">1.3.1</a>, <a href="#rfc.xref.Part1.7">1.3.1</a>, <a href="#rfc.xref.Part1.8">1.3.1</a>, <a href="#rfc.xref.Part1.9">1.3.1</a>, <a href="#rfc.xref.Part1.10">1.3.1</a>, <a href="#rfc.xref.Part1.11">1.3.1</a>, <a href="#rfc.xref.Part1.12">1.3.2</a>, <a href="#rfc.xref.Part1.13">1.3.2</a>, <a href="#rfc.xref.Part1.14">1.3.2</a>, <a href="#rfc.xref.Part1.15">1.3.2</a>, <a href="#rfc.xref.Part1.16">2</a>, <a href="#rfc.xref.Part1.17">2.2.1</a>, <a href="#rfc.xref.Part1.18">2.3.1</a>, <a href="#rfc.xref.Part1.19">2.3.7</a>, <a href="#rfc.xref.Part1.20">2.3.7</a>, <a href="#rfc.xref.Part1.21">2.3.8</a>, <a href="#rfc.xref.Part1.22">3</a>, <a href="#rfc.xref.Part1.23">3.1</a>, <a href="#rfc.xref.Part1.24">3.1</a>, <a href="#rfc.xref.Part1.25">3.1</a>, <a href="#rfc.xref.Part1.26">3.1</a>, <a href="#rfc.xref.Part1.27">3.1</a>, <a href="#rfc.xref.Part1.28">3.2</a>, <a href="#rfc.xref.Part1.29">3.2</a>, <a href="#rfc.xref.Part1.30">3.3</a>, <a href="#rfc.xref.Part1.31">4.3.1</a>, <a href="#rfc.xref.Part1.32">4.3.2</a>, <a href="#rfc.xref.Part1.33">4.4.4</a>, <a href="#rfc.xref.Part1.34">4.4.6</a>, <a href="#rfc.xref.Part1.35">4.6.15</a>, <a href="#rfc.xref.Part1.36">4.7.6</a>, <a href="#rfc.xref.Part1.37">5</a>, <a href="#rfc.xref.Part1.38">5.1</a>, <a href="#rfc.xref.Part1.39">7.3</a>, <a href="#rfc.xref.Part1.40">7.9</a>, <a href="#rfc.xref.Part1.41">7.9</a>, <a href="#rfc.xref.Part1.42">7.10</a>, <a href="#rfc.xref.Part1.43">10</a>, <a href="#Part1"><b>11.1</b></a>, <a href="#rfc.xref.Part1.44">A</a> <ul>5012 <li><em>Part1</em> <a href="#rfc.xref.Part1.1">1</a>, <a href="#rfc.xref.Part1.2">1.2</a>, <a href="#rfc.xref.Part1.3">1.3</a>, <a href="#rfc.xref.Part1.4">1.3.1</a>, <a href="#rfc.xref.Part1.5">1.3.1</a>, <a href="#rfc.xref.Part1.6">1.3.1</a>, <a href="#rfc.xref.Part1.7">1.3.1</a>, <a href="#rfc.xref.Part1.8">1.3.1</a>, <a href="#rfc.xref.Part1.9">1.3.1</a>, <a href="#rfc.xref.Part1.10">1.3.1</a>, <a href="#rfc.xref.Part1.11">1.3.1</a>, <a href="#rfc.xref.Part1.12">1.3.2</a>, <a href="#rfc.xref.Part1.13">1.3.2</a>, <a href="#rfc.xref.Part1.14">1.3.2</a>, <a href="#rfc.xref.Part1.15">1.3.2</a>, <a href="#rfc.xref.Part1.16">2</a>, <a href="#rfc.xref.Part1.17">2.2.1</a>, <a href="#rfc.xref.Part1.18">2.3.1</a>, <a href="#rfc.xref.Part1.19">2.3.7</a>, <a href="#rfc.xref.Part1.20">2.3.7</a>, <a href="#rfc.xref.Part1.21">2.3.8</a>, <a href="#rfc.xref.Part1.22">3</a>, <a href="#rfc.xref.Part1.23">3.1</a>, <a href="#rfc.xref.Part1.24">3.1</a>, <a href="#rfc.xref.Part1.25">3.1</a>, <a href="#rfc.xref.Part1.26">3.1</a>, <a href="#rfc.xref.Part1.27">3.1</a>, <a href="#rfc.xref.Part1.28">3.2</a>, <a href="#rfc.xref.Part1.29">3.2</a>, <a href="#rfc.xref.Part1.30">3.3</a>, <a href="#rfc.xref.Part1.31">4.3.1</a>, <a href="#rfc.xref.Part1.32">4.3.2</a>, <a href="#rfc.xref.Part1.33">4.4.4</a>, <a href="#rfc.xref.Part1.34">4.4.6</a>, <a href="#rfc.xref.Part1.35">4.6.15</a>, <a href="#rfc.xref.Part1.36">4.7.6</a>, <a href="#rfc.xref.Part1.37">5</a>, <a href="#rfc.xref.Part1.38">5.1</a>, <a href="#rfc.xref.Part1.39">7.3</a>, <a href="#rfc.xref.Part1.40">7.9</a>, <a href="#rfc.xref.Part1.41">7.9</a>, <a href="#rfc.xref.Part1.42">7.10</a>, <a href="#rfc.xref.Part1.43">10</a>, <a href="#Part1"><b>11.1</b></a>, <a href="#rfc.xref.Part1.44">A</a>, <a href="#rfc.xref.Part1.45">D.1.2</a>, <a href="#rfc.xref.Part1.46">D.1.2</a>, <a href="#rfc.xref.Part1.47">D.1.2</a>, <a href="#rfc.xref.Part1.48">D.1.2.1</a>, <a href="#rfc.xref.Part1.49">D.1.2.1</a>, <a href="#rfc.xref.Part1.50">D.2.1</a>, <a href="#rfc.xref.Part1.51">D.2.2</a>, <a href="#rfc.xref.Part1.52">D.4.1</a>, <a href="#rfc.xref.Part1.53">D.5.1</a>, <a href="#rfc.xref.Part1.54">D.5.3</a>, <a href="#rfc.xref.Part1.55">D.5.7</a>, <a href="#rfc.xref.Part1.56">D.6.1</a>, <a href="#rfc.xref.Part1.57">D.6.1</a>, <a href="#rfc.xref.Part1.58">D.6.1</a>, <a href="#rfc.xref.Part1.59">D.8.6</a><ul> 3693 5013 <li><em>Section 1.2</em> <a href="#rfc.xref.Part1.3">1.3</a></li> 3694 5014 <li><em>Section 2</em> <a href="#rfc.xref.Part1.2">1.2</a></li> … … 3700 5020 <li><em>Section 3.2.4</em> <a href="#rfc.xref.Part1.8">1.3.1</a>, <a href="#rfc.xref.Part1.9">1.3.1</a>, <a href="#rfc.xref.Part1.10">1.3.1</a>, <a href="#rfc.xref.Part1.11">1.3.1</a>, <a href="#rfc.xref.Part1.13">1.3.2</a>, <a href="#rfc.xref.Part1.24">3.1</a></li> 3701 5021 <li><em>Section 3.2.5</em> <a href="#rfc.xref.Part1.23">3.1</a></li> 3702 <li><em>Section 3.3</em> <a href="#rfc.xref.Part1.17">2.2.1</a>, <a href="#rfc.xref.Part1.34">4.4.6</a>, <a href="#rfc.xref.Part1.37">5</a></li> 5022 <li><em>Section 3.3</em> <a href="#rfc.xref.Part1.17">2.2.1</a>, <a href="#rfc.xref.Part1.34">4.4.6</a>, <a href="#rfc.xref.Part1.37">5</a>, <a href="#rfc.xref.Part1.51">D.2.2</a></li> 5023 <li><em>Section 3.3.1</em> <a href="#rfc.xref.Part1.59">D.8.6</a></li> 5024 <li><em>Section 3.3.2</em> <a href="#rfc.xref.Part1.50">D.2.1</a></li> 5025 <li><em>Section 4</em> <a href="#rfc.xref.Part1.48">D.1.2.1</a></li> 3703 5026 <li><em>Section 4.1</em> <a href="#rfc.xref.Part1.27">3.1</a></li> 5027 <li><em>Section 4.2.1</em> <a href="#rfc.xref.Part1.45">D.1.2</a>, <a href="#rfc.xref.Part1.56">D.6.1</a></li> 5028 <li><em>Section 4.2</em> <a href="#rfc.xref.Part1.49">D.1.2.1</a></li> 5029 <li><em>Section 4.2.2</em> <a href="#rfc.xref.Part1.46">D.1.2</a>, <a href="#rfc.xref.Part1.57">D.6.1</a></li> 5030 <li><em>Section 4.2.3</em> <a href="#rfc.xref.Part1.47">D.1.2</a>, <a href="#rfc.xref.Part1.58">D.6.1</a></li> 3704 5031 <li><em>Section 4.3</em> <a href="#rfc.xref.Part1.29">3.2</a></li> 5032 <li><em>Section 4.3.1</em> <a href="#rfc.xref.Part1.52">D.4.1</a>, <a href="#rfc.xref.Part1.53">D.5.1</a>, <a href="#rfc.xref.Part1.54">D.5.3</a></li> 3705 5033 <li><em>Section 5.3</em> <a href="#rfc.xref.Part1.18">2.3.1</a>, <a href="#rfc.xref.Part1.21">2.3.8</a></li> 3706 5034 <li><em>Section 5.4</em> <a href="#rfc.xref.Part1.28">3.2</a></li> 3707 <li><em>Section 5.5</em> <a href="#rfc.xref.Part1.16">2</a>, <a href="#rfc.xref.Part1.30">3.3</a>, <a href="#rfc.xref.Part1.38">5.1</a> </li>5035 <li><em>Section 5.5</em> <a href="#rfc.xref.Part1.16">2</a>, <a href="#rfc.xref.Part1.30">3.3</a>, <a href="#rfc.xref.Part1.38">5.1</a>, <a href="#rfc.xref.Part1.55">D.5.7</a></li> 3708 5036 <li><em>Section 6.1</em> <a href="#rfc.xref.Part1.26">3.1</a></li> 3709 5037 <li><em>Section 6.2</em> <a href="#rfc.xref.Part1.19">2.3.7</a>, <a href="#rfc.xref.Part1.41">7.9</a>, <a href="#rfc.xref.Part1.44">A</a></li> … … 3714 5042 </ul> 3715 5043 </li> 3716 <li><em>Part3</em> <a href="#rfc.xref.Part3.1">2.3.4</a>, <a href="#rfc.xref.Part3.2">3.1</a>, <a href="#rfc.xref.Part3.3">3.1</a>, <a href="#rfc.xref.Part3.4">3.2</a>, <a href="#rfc.xref.Part3.5">3.2</a>, <a href="#rfc.xref.Part3.6">3.2</a>, <a href="#rfc.xref.Part3.7">3.2</a>, <a href="#rfc.xref.Part3.8">4</a>, <a href="#rfc.xref.Part3.9">4.5</a>, <a href="#rfc.xref.Part3.10">4.5.1</a>, <a href="#rfc.xref.Part3.11">4.6.6</a>, <a href="#rfc.xref.Part3.12">5</a>, <a href="#rfc.xref.Part3.13">7.5</a>, <a href="#Part3"><b>11.1</b></a><ul> 3717 <li><em>Section 2.3</em> <a href="#rfc.xref.Part3.3">3.1</a></li> 3718 <li><em>Section 5</em> <a href="#rfc.xref.Part3.10">4.5.1</a></li> 3719 <li><em>Section 5.2</em> <a href="#rfc.xref.Part3.9">4.5</a></li> 3720 <li><em>Section 6.1</em> <a href="#rfc.xref.Part3.4">3.2</a></li> 3721 <li><em>Section 6</em> <a href="#rfc.xref.Part3.11">4.6.6</a></li> 3722 <li><em>Section 6.2</em> <a href="#rfc.xref.Part3.5">3.2</a></li> 3723 <li><em>Section 6.3</em> <a href="#rfc.xref.Part3.6">3.2</a></li> 3724 <li><em>Section 6.4</em> <a href="#rfc.xref.Part3.7">3.2</a></li> 3725 <li><em>Section 6.7</em> <a href="#rfc.xref.Part3.1">2.3.4</a>, <a href="#rfc.xref.Part3.13">7.5</a></li> 3726 <li><em>Section 6.8</em> <a href="#rfc.xref.Part3.2">3.1</a>, <a href="#rfc.xref.Part3.8">4</a></li> 3727 </ul> 3728 </li> 3729 <li><em>Part4</em> <a href="#rfc.xref.Part4.1">3.2</a>, <a href="#rfc.xref.Part4.2">3.2</a>, <a href="#rfc.xref.Part4.3">3.2</a>, <a href="#rfc.xref.Part4.4">3.2</a>, <a href="#rfc.xref.Part4.5">3.3</a>, <a href="#rfc.xref.Part4.6">4.1</a>, <a href="#rfc.xref.Part4.7">4.1</a>, <a href="#rfc.xref.Part4.8">4.1</a>, <a href="#rfc.xref.Part4.9">4.4.2</a>, <a href="#rfc.xref.Part4.10">4.5</a>, <a href="#Part4"><b>11.1</b></a>, <a href="#rfc.xref.Part4.11">C.2</a><ul> 3730 <li><em>Section 2.3</em> <a href="#rfc.xref.Part4.5">3.3</a>, <a href="#rfc.xref.Part4.9">4.4.2</a></li> 5044 <li><em>Part4</em> <a href="#rfc.xref.Part4.1">3.2</a>, <a href="#rfc.xref.Part4.2">3.2</a>, <a href="#rfc.xref.Part4.3">3.2</a>, <a href="#rfc.xref.Part4.4">3.2</a>, <a href="#rfc.xref.Part4.5">3.3</a>, <a href="#rfc.xref.Part4.6">4.1</a>, <a href="#rfc.xref.Part4.7">4.1</a>, <a href="#rfc.xref.Part4.8">4.1</a>, <a href="#rfc.xref.Part4.9">4.4.2</a>, <a href="#rfc.xref.Part4.10">4.5</a>, <a href="#Part4"><b>11.1</b></a>, <a href="#rfc.xref.Part4.11">C.2</a>, <a href="#rfc.xref.Part4.12">D.3.1</a>, <a href="#rfc.xref.Part4.13">D.3.1</a><ul> 5045 <li><em>Section 2.2</em> <a href="#rfc.xref.Part4.13">D.3.1</a></li> 5046 <li><em>Section 2.3</em> <a href="#rfc.xref.Part4.5">3.3</a>, <a href="#rfc.xref.Part4.9">4.4.2</a>, <a href="#rfc.xref.Part4.12">D.3.1</a></li> 3731 5047 <li><em>Section 3.1</em> <a href="#rfc.xref.Part4.1">3.2</a></li> 3732 5048 <li><em>Section 3.2</em> <a href="#rfc.xref.Part4.3">3.2</a></li> … … 3738 5054 </ul> 3739 5055 </li> 3740 <li><em>Part5</em> <a href="#rfc.xref.Part5.1">2.3.2</a>, <a href="#rfc.xref.Part5.2">3.2</a>, <a href="#rfc.xref.Part5.3">3.2</a>, <a href="#rfc.xref.Part5.4">3.3</a>, <a href="#rfc.xref.Part5.5">4.1</a>, <a href="#rfc.xref.Part5.6">4.1</a>, <a href="#rfc.xref.Part5.7">4.1</a>, <a href="#Part5"><b>11.1</b></a> <ul>5056 <li><em>Part5</em> <a href="#rfc.xref.Part5.1">2.3.2</a>, <a href="#rfc.xref.Part5.2">3.2</a>, <a href="#rfc.xref.Part5.3">3.2</a>, <a href="#rfc.xref.Part5.4">3.3</a>, <a href="#rfc.xref.Part5.5">4.1</a>, <a href="#rfc.xref.Part5.6">4.1</a>, <a href="#rfc.xref.Part5.7">4.1</a>, <a href="#Part5"><b>11.1</b></a>, <a href="#rfc.xref.Part5.8">D.2.1</a><ul> 3741 5057 <li><em>Section 3</em> <a href="#rfc.xref.Part5.5">4.1</a></li> 3742 5058 <li><em>Section 3.1</em> <a href="#rfc.xref.Part5.6">4.1</a></li> 3743 5059 <li><em>Section 3.2</em> <a href="#rfc.xref.Part5.7">4.1</a></li> 3744 5060 <li><em>Section 5.1</em> <a href="#rfc.xref.Part5.4">3.3</a></li> 5061 <li><em>Section 5.2</em> <a href="#rfc.xref.Part5.8">D.2.1</a></li> 3745 5062 <li><em>Section 5.3</em> <a href="#rfc.xref.Part5.2">3.2</a></li> 3746 5063 <li><em>Section 5.4</em> <a href="#rfc.xref.Part5.1">2.3.2</a>, <a href="#rfc.xref.Part5.3">3.2</a></li> 3747 5064 </ul> 3748 5065 </li> 3749 <li><em>Part6</em> <a href="#rfc.xref.Part6.1">2.2.1</a>, <a href="#rfc.xref.Part6.2">2.3.2</a>, <a href="#rfc.xref.Part6.3">2.3.3</a>, <a href="#rfc.xref.Part6.4">2.3.4</a>, <a href="#rfc.xref.Part6.5">2.3.5</a>, <a href="#rfc.xref.Part6.6">2.3.6</a>, <a href="#rfc.xref.Part6.7">3.1</a>, <a href="#rfc.xref.Part6.8">3.3</a>, <a href="#rfc.xref.Part6.9">3.3</a>, <a href="#rfc.xref.Part6.10">4.2.1</a>, <a href="#rfc.xref.Part6.11">4.4.1</a>, <a href="#rfc.xref.Part6.12">4.4.4</a>, <a href="#rfc.xref.Part6.13">4.4.4</a>, <a href="#rfc.xref.Part6.14">4.4.4</a>, <a href="#rfc.xref.Part6.15">4.5.1</a>, <a href="#rfc.xref.Part6.16">4.5.2</a>, <a href="#rfc.xref.Part6.17">4.6.9</a>, <a href="#Part6"><b>11.1</b></a> <ul>5066 <li><em>Part6</em> <a href="#rfc.xref.Part6.1">2.2.1</a>, <a href="#rfc.xref.Part6.2">2.3.2</a>, <a href="#rfc.xref.Part6.3">2.3.3</a>, <a href="#rfc.xref.Part6.4">2.3.4</a>, <a href="#rfc.xref.Part6.5">2.3.5</a>, <a href="#rfc.xref.Part6.6">2.3.6</a>, <a href="#rfc.xref.Part6.7">3.1</a>, <a href="#rfc.xref.Part6.8">3.3</a>, <a href="#rfc.xref.Part6.9">3.3</a>, <a href="#rfc.xref.Part6.10">4.2.1</a>, <a href="#rfc.xref.Part6.11">4.4.1</a>, <a href="#rfc.xref.Part6.12">4.4.4</a>, <a href="#rfc.xref.Part6.13">4.4.4</a>, <a href="#rfc.xref.Part6.14">4.4.4</a>, <a href="#rfc.xref.Part6.15">4.5.1</a>, <a href="#rfc.xref.Part6.16">4.5.2</a>, <a href="#rfc.xref.Part6.17">4.6.9</a>, <a href="#Part6"><b>11.1</b></a>, <a href="#rfc.xref.Part6.18">D.3.1</a>, <a href="#rfc.xref.Part6.19">D.4.1</a><ul> 3750 5067 <li><em>Section 2.3.1</em> <a href="#rfc.xref.Part6.4">2.3.4</a></li> 3751 5068 <li><em>Section 2.3.1.1</em> <a href="#rfc.xref.Part6.11">4.4.1</a>, <a href="#rfc.xref.Part6.14">4.4.4</a>, <a href="#rfc.xref.Part6.15">4.5.1</a>, <a href="#rfc.xref.Part6.16">4.5.2</a>, <a href="#rfc.xref.Part6.17">4.6.9</a></li> … … 3754 5071 <li><em>Section 3.1</em> <a href="#rfc.xref.Part6.8">3.3</a></li> 3755 5072 <li><em>Section 3.2</em> <a href="#rfc.xref.Part6.12">4.4.4</a></li> 3756 <li><em>Section 3.5</em> <a href="#rfc.xref.Part6.9">3.3</a></li> 5073 <li><em>Section 3.3</em> <a href="#rfc.xref.Part6.18">D.3.1</a></li> 5074 <li><em>Section 3.5</em> <a href="#rfc.xref.Part6.9">3.3</a>, <a href="#rfc.xref.Part6.19">D.4.1</a></li> 3757 5075 <li><em>Section 3.6</em> <a href="#rfc.xref.Part6.13">4.4.4</a></li> 3758 5076 </ul> … … 3768 5086 </ul> 3769 5087 </li> 5088 <li>payload <a href="#rfc.iref.p.3">D.2</a></li> 3770 5089 <li>POST method <a href="#rfc.iref.p.1"><b>2.3.4</b></a>, <a href="#rfc.xref.POST.1">8.1</a>, <a href="#rfc.xref.POST.2">A</a></li> 3771 5090 <li>PUT method <a href="#rfc.iref.p.2"><b>2.3.5</b></a>, <a href="#rfc.xref.PUT.1">8.1</a>, <a href="#rfc.xref.PUT.2">A</a></li> … … 3774 5093 <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul> 3775 5094 <li>Referer header field <a href="#rfc.xref.header.referer.1">3.2</a>, <a href="#rfc.iref.r.1"><b>7.7</b></a>, <a href="#rfc.xref.header.referer.2">8.3</a>, <a href="#rfc.xref.header.referer.3">A</a></li> 5095 <li>representation <a href="#rfc.iref.r.3">D.3</a></li> 3776 5096 <li>Retry-After header field <a href="#rfc.xref.header.retry-after.1">3.3</a>, <a href="#rfc.xref.header.retry-after.2">4.7.4</a>, <a href="#rfc.iref.r.2"><b>7.8</b></a>, <a href="#rfc.xref.header.retry-after.3">8.3</a></li> 3777 5097 <li><em>RFC1123</em> <a href="#rfc.xref.RFC1123.1">6.1</a>, <a href="#rfc.xref.RFC1123.2">6.1</a>, <a href="#RFC1123"><b>11.2</b></a><ul> … … 3779 5099 </ul> 3780 5100 </li> 3781 <li><em>RFC1945</em> <a href="#rfc.xref.RFC1945.1">4.5</a>, <a href="#RFC1945"><b>11.2</b></a> <ul>5101 <li><em>RFC1945</em> <a href="#rfc.xref.RFC1945.1">4.5</a>, <a href="#RFC1945"><b>11.2</b></a>, <a href="#rfc.xref.RFC1945.2">D.9</a><ul> 3782 5102 <li><em>Section 9.3</em> <a href="#rfc.xref.RFC1945.1">4.5</a></li> 3783 5103 </ul> 3784 5104 </li> 3785 <li><em>RFC1950</em> <a href="#RFC1950"><b>11.1</b></a></li> 3786 <li><em>RFC1951</em> <a href="#RFC1951"><b>11.1</b></a></li> 3787 <li><em>RFC1952</em> <a href="#RFC1952"><b>11.1</b></a></li> 3788 <li><em>RFC2045</em> <a href="#RFC2045"><b>11.1</b></a></li> 3789 <li><em>RFC2046</em> <a href="#RFC2046"><b>11.1</b></a></li> 3790 <li><em>RFC2049</em> <a href="#RFC2049"><b>11.2</b></a></li> 3791 <li><em>RFC2068</em> <a href="#rfc.xref.RFC2068.1">4.5</a>, <a href="#rfc.xref.RFC2068.2">4.5</a>, <a href="#RFC2068"><b>11.2</b></a><ul> 5105 <li><em>RFC1950</em> <a href="#RFC1950"><b>11.1</b></a>, <a href="#rfc.xref.RFC1950.1">D.6.1</a></li> 5106 <li><em>RFC1951</em> <a href="#RFC1951"><b>11.1</b></a>, <a href="#rfc.xref.RFC1951.1">D.6.1</a></li> 5107 <li><em>RFC1952</em> <a href="#RFC1952"><b>11.1</b></a>, <a href="#rfc.xref.RFC1952.1">D.6.1</a></li> 5108 <li><em>RFC2045</em> <a href="#RFC2045"><b>11.1</b></a>, <a href="#rfc.xref.RFC2045.1">D.8</a>, <a href="#rfc.xref.RFC2045.2">D.8.1</a></li> 5109 <li><em>RFC2046</em> <a href="#RFC2046"><b>11.1</b></a>, <a href="#rfc.xref.RFC2046.1">D.1.3</a>, <a href="#rfc.xref.RFC2046.2">D.1.3.2</a>, <a href="#rfc.xref.RFC2046.3">D.3.2</a>, <a href="#rfc.xref.RFC2046.4">D.8.2</a><ul> 5110 <li><em>Section 4.5.1</em> <a href="#rfc.xref.RFC2046.3">D.3.2</a></li> 5111 <li><em>Section 5.1.1</em> <a href="#rfc.xref.RFC2046.2">D.1.3.2</a></li> 5112 </ul> 5113 </li> 5114 <li><em>RFC2049</em> <a href="#RFC2049"><b>11.2</b></a>, <a href="#rfc.xref.RFC2049.1">D.8.2</a><ul> 5115 <li><em>Section 4</em> <a href="#rfc.xref.RFC2049.1">D.8.2</a></li> 5116 </ul> 5117 </li> 5118 <li><em>RFC2068</em> <a href="#rfc.xref.RFC2068.1">4.5</a>, <a href="#rfc.xref.RFC2068.2">4.5</a>, <a href="#RFC2068"><b>11.2</b></a>, <a href="#rfc.xref.RFC2068.3">D.9</a><ul> 3792 5119 <li><em>Section 10.3</em> <a href="#rfc.xref.RFC2068.2">4.5</a></li> 3793 5120 <li><em>Section 10.3.4</em> <a href="#rfc.xref.RFC2068.1">4.5</a></li> 3794 5121 </ul> 3795 5122 </li> 3796 <li><em>RFC2076</em> <a href="#RFC2076"><b>11.2</b></a> </li>5123 <li><em>RFC2076</em> <a href="#RFC2076"><b>11.2</b></a>, <a href="#rfc.xref.RFC2076.1">D.9</a></li> 3797 5124 <li><em>RFC2119</em> <a href="#rfc.xref.RFC2119.1">1.2</a>, <a href="#RFC2119"><b>11.1</b></a></li> 3798 <li><em>RFC2277</em> <a href="#RFC2277"><b>11.2</b></a></li> 3799 <li><em>RFC2295</em> <a href="#RFC2295"><b>11.2</b></a></li> 3800 <li><em>RFC2388</em> <a href="#RFC2388"><b>11.2</b></a></li> 3801 <li><em>RFC2557</em> <a href="#RFC2557"><b>11.2</b></a></li> 3802 <li><em>RFC2616</em> <a href="#rfc.xref.RFC2616.1">1</a>, <a href="#rfc.xref.RFC2616.2">4.5</a>, <a href="#RFC2616"><b>11.2</b></a>, <a href="#rfc.xref.RFC2616.3">C.1</a><ul> 5125 <li><em>RFC2277</em> <a href="#RFC2277"><b>11.2</b></a>, <a href="#rfc.xref.RFC2277.1">D.1.1</a></li> 5126 <li><em>RFC2295</em> <a href="#RFC2295"><b>11.2</b></a>, <a href="#rfc.xref.RFC2295.1">D.4</a></li> 5127 <li><em>RFC2388</em> <a href="#RFC2388"><b>11.2</b></a>, <a href="#rfc.xref.RFC2388.1">D.1.3.2</a></li> 5128 <li><em>RFC2557</em> <a href="#RFC2557"><b>11.2</b></a>, <a href="#rfc.xref.RFC2557.1">D.5.7</a>, <a href="#rfc.xref.RFC2557.2">D.8.7</a><ul> 5129 <li><em>Section 4</em> <a href="#rfc.xref.RFC2557.1">D.5.7</a></li> 5130 </ul> 5131 </li> 5132 <li><em>RFC2616</em> <a href="#rfc.xref.RFC2616.1">1</a>, <a href="#rfc.xref.RFC2616.2">4.5</a>, <a href="#RFC2616"><b>11.2</b></a>, <a href="#rfc.xref.RFC2616.3">C.1</a>, <a href="#rfc.xref.RFC2616.4">D.5.4</a>, <a href="#rfc.xref.RFC2616.5">D.11.1</a><ul> 3803 5133 <li><em>Section 10.3.8</em> <a href="#rfc.xref.RFC2616.2">4.5</a></li> 5134 <li><em>Section 14.4</em> <a href="#rfc.xref.RFC2616.4">D.5.4</a></li> 3804 5135 </ul> 3805 5136 </li> … … 3808 5139 </ul> 3809 5140 </li> 3810 <li><em>RFC3629</em> <a href="#RFC3629"><b>11.2</b></a> </li>5141 <li><em>RFC3629</em> <a href="#RFC3629"><b>11.2</b></a>, <a href="#rfc.xref.RFC3629.1">D.1.1</a></li> 3811 5142 <li><em>RFC3864</em> <a href="#rfc.xref.RFC3864.1">3.1</a>, <a href="#rfc.xref.RFC3864.2">3.1</a>, <a href="#rfc.xref.RFC3864.3">8.3</a>, <a href="#RFC3864"><b>11.2</b></a><ul> 3812 5143 <li><em>Section 4.1</em> <a href="#rfc.xref.RFC3864.2">3.1</a></li> … … 3818 5149 </ul> 3819 5150 </li> 3820 <li><em>RFC4288</em> <a href="#RFC4288"><b>11.2</b></a></li> 3821 <li><em>RFC4647</em> <a href="#RFC4647"><b>11.1</b></a></li> 3822 <li><em>RFC5226</em> <a href="#rfc.xref.RFC5226.1">2.2</a>, <a href="#rfc.xref.RFC5226.2">4.2</a>, <a href="#RFC5226"><b>11.2</b></a><ul> 3823 <li><em>Section 4.1</em> <a href="#rfc.xref.RFC5226.1">2.2</a>, <a href="#rfc.xref.RFC5226.2">4.2</a></li> 5151 <li><em>RFC4288</em> <a href="#RFC4288"><b>11.2</b></a>, <a href="#rfc.xref.RFC4288.1">D.1.3</a></li> 5152 <li><em>RFC4647</em> <a href="#RFC4647"><b>11.1</b></a>, <a href="#rfc.xref.RFC4647.1">D.5.4</a>, <a href="#rfc.xref.RFC4647.2">D.5.4</a>, <a href="#rfc.xref.RFC4647.3">D.5.4</a>, <a href="#rfc.xref.RFC4647.4">D.5.4</a><ul> 5153 <li><em>Section 2.1</em> <a href="#rfc.xref.RFC4647.1">D.5.4</a></li> 5154 <li><em>Section 2.3</em> <a href="#rfc.xref.RFC4647.2">D.5.4</a></li> 5155 <li><em>Section 3</em> <a href="#rfc.xref.RFC4647.3">D.5.4</a></li> 5156 <li><em>Section 3.3.1</em> <a href="#rfc.xref.RFC4647.4">D.5.4</a></li> 5157 </ul> 5158 </li> 5159 <li><em>RFC5226</em> <a href="#rfc.xref.RFC5226.1">2.2</a>, <a href="#rfc.xref.RFC5226.2">4.2</a>, <a href="#RFC5226"><b>11.2</b></a>, <a href="#rfc.xref.RFC5226.3">D.1.2.1</a><ul> 5160 <li><em>Section 4.1</em> <a href="#rfc.xref.RFC5226.1">2.2</a>, <a href="#rfc.xref.RFC5226.2">4.2</a>, <a href="#rfc.xref.RFC5226.3">D.1.2.1</a></li> 3824 5161 </ul> 3825 5162 </li> … … 3828 5165 </ul> 3829 5166 </li> 3830 <li><em>RFC5322</em> <a href="#rfc.xref.RFC5322.1">6.1</a>, <a href="#rfc.xref.RFC5322.2">7.2</a>, <a href="#rfc.xref.RFC5322.3">7.4</a>, <a href="#rfc.xref.RFC5322.4">7.4</a>, <a href="#RFC5322"><b>11.2</b></a> <ul>5167 <li><em>RFC5322</em> <a href="#rfc.xref.RFC5322.1">6.1</a>, <a href="#rfc.xref.RFC5322.2">7.2</a>, <a href="#rfc.xref.RFC5322.3">7.4</a>, <a href="#rfc.xref.RFC5322.4">7.4</a>, <a href="#RFC5322"><b>11.2</b></a>, <a href="#rfc.xref.RFC5322.5">D.8</a><ul> 3831 5168 <li><em>Section 3.3</em> <a href="#rfc.xref.RFC5322.1">6.1</a></li> 3832 5169 <li><em>Section 3.4</em> <a href="#rfc.xref.RFC5322.3">7.4</a>, <a href="#rfc.xref.RFC5322.4">7.4</a></li> … … 3834 5171 </ul> 3835 5172 </li> 3836 <li><em>RFC5646</em> <a href="#RFC5646"><b>11.1</b></a></li> 5173 <li><em>RFC5646</em> <a href="#RFC5646"><b>11.1</b></a>, <a href="#rfc.xref.RFC5646.1">D.1.4</a>, <a href="#rfc.xref.RFC5646.2">D.1.4</a>, <a href="#rfc.xref.RFC5646.3">D.1.4</a><ul> 5174 <li><em>Section 2.1</em> <a href="#rfc.xref.RFC5646.2">D.1.4</a></li> 5175 </ul> 5176 </li> 3837 5177 <li><em>RFC5789</em> <a href="#rfc.xref.RFC5789.1">2.3.5</a>, <a href="#RFC5789"><b>11.2</b></a></li> 3838 5178 <li><em>RFC5987</em> <a href="#rfc.xref.RFC5987.1">3.1</a>, <a href="#RFC5987"><b>11.2</b></a></li> 3839 <li><em>RFC6151</em> <a href="#RFC6151"><b>11.2</b></a> </li>3840 <li><em>RFC6266</em> <a href="#RFC6266"><b>11.2</b></a> </li>5179 <li><em>RFC6151</em> <a href="#RFC6151"><b>11.2</b></a>, <a href="#rfc.xref.RFC6151.1">D.10</a></li> 5180 <li><em>RFC6266</em> <a href="#RFC6266"><b>11.2</b></a>, <a href="#rfc.xref.RFC6266.1">D.9</a>, <a href="#rfc.xref.RFC6266.2">D.10</a></li> 3841 5181 </ul> 3842 5182 </li> … … 3892 5232 </li> 3893 5233 <li><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul> 3894 <li>User-Agent header field <a href="#rfc.xref.header.user-agent.1">3.2</a>, <a href="#rfc.iref.u.1"><b>7.10</b></a>, <a href="#rfc.xref.header.user-agent.2">8.3</a>, <a href="#rfc.xref.header.user-agent.3">9.1</a> </li>5234 <li>User-Agent header field <a href="#rfc.xref.header.user-agent.1">3.2</a>, <a href="#rfc.iref.u.1"><b>7.10</b></a>, <a href="#rfc.xref.header.user-agent.2">8.3</a>, <a href="#rfc.xref.header.user-agent.3">9.1</a>, <a href="#rfc.xref.header.user-agent.4">D.4.1</a></li> 3895 5235 </ul> 3896 5236 </li> -
draft-ietf-httpbis/latest/p2-semantics.xml
r1642 r1643 20 20 <!ENTITY acks "<xref target='Part1' x:rel='#acks' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 21 21 <!ENTITY messaging "<xref target='Part1' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 22 <!ENTITY payload "<xref target='Part3' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">23 22 <!ENTITY conditional "<xref target='Part4' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 24 23 <!ENTITY range "<xref target='Part5' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 25 24 <!ENTITY caching "<xref target='Part6' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 26 25 <!ENTITY auth "<xref target='Part7' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 27 <!ENTITY content-negotiation "<xref target=' Part3' x:rel='#content.negotiation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">28 <!ENTITY agent-driven-negotiation "<xref target=' Part3' x:rel='#agent-driven.negotiation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">26 <!ENTITY content-negotiation "<xref target='content.negotiation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 27 <!ENTITY agent-driven-negotiation "<xref target='agent-driven.negotiation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 29 28 <!ENTITY abnf-extension "<xref target='Part1' x:rel='#abnf.extension' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 30 29 <!ENTITY whitespace "<xref target='Part1' x:rel='#whitespace' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 37 36 <!ENTITY http-version "<xref target='Part1' x:rel='#http.version' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 38 37 <!ENTITY use100 "<xref target='Part1' x:rel='#use.of.the.100.status' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 39 <!ENTITY qvalue "<xref target='Part3' x:rel='#quality.values' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">40 38 <!ENTITY request-target "<xref target='Part1' x:rel='#request-target' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 41 <!ENTITY header-accept "<xref target=' Part3' x:rel='#header.accept' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">42 <!ENTITY header-accept-charset "<xref target=' Part3' x:rel='#header.accept-charset' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">43 <!ENTITY header-accept-encoding "<xref target=' Part3' x:rel='#header.accept-encoding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">44 <!ENTITY header-accept-language "<xref target=' Part3' x:rel='#header.accept-language' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">39 <!ENTITY header-accept "<xref target='header.accept' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 40 <!ENTITY header-accept-charset "<xref target='header.accept-charset' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 41 <!ENTITY header-accept-encoding "<xref target='header.accept-encoding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 42 <!ENTITY header-accept-language "<xref target='header.accept-language' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 45 43 <!ENTITY header-accept-ranges "<xref target='Part5' x:rel='#header.accept-ranges' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 46 44 <!ENTITY header-age "<xref target='Part6' x:rel='#header.age' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 48 46 <!ENTITY header-cache-control "<xref target='Part6' x:rel='#header.cache-control' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 49 47 <!ENTITY header-connection "<xref target='Part1' x:rel='#header.connection' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 50 <!ENTITY header-content-location "<xref target=' Part3' x:rel='#header.content-location' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">48 <!ENTITY header-content-location "<xref target='header.content-location' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 51 49 <!ENTITY header-content-range "<xref target='Part5' x:rel='#header.content-range' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 52 <!ENTITY header-content-type "<xref target=' Part3' x:rel='#header.content-type' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">50 <!ENTITY header-content-type "<xref target='header.content-type' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 53 51 <!ENTITY header-etag "<xref target='Part4' x:rel='#header.etag' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 54 52 <!ENTITY header-expires "<xref target='Part6' x:rel='#header.expires' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 70 68 <!ENTITY header-warning "<xref target='Part6' x:rel='#header.warning' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 71 69 <!ENTITY header-www-authenticate "<xref target='Part7' x:rel='#header.www-authenticate' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 72 <!ENTITY media-types "<xref target=' Part3' x:rel='#media.types' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">70 <!ENTITY media-types "<xref target='media.types' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 73 71 <!ENTITY message-body "<xref target='Part1' x:rel='#message.body' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 74 72 <!ENTITY media-type-message-http "<xref target='Part1' x:rel='#internet.media.type.message.http' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 79 77 <!ENTITY status-412 "<xref target='Part4' x:rel='#status.412' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 80 78 <!ENTITY status-416 "<xref target='Part5' x:rel='#status.416' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 81 <!ENTITY p3-header-fields "<xref target='Part3' x:rel='#header.field.definitions' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">82 79 <!ENTITY p4-status-codes "<xref target='Part4' x:rel='#status.code.definitions' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 83 80 <!ENTITY p5-status-codes "<xref target='Part5' x:rel='#status.code.definitions' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 100 97 <!ENTITY header-expires "<xref target='Part6' x:rel='#header.expires' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 101 98 <!ENTITY header-last-modified "<xref target='Part4' x:rel='#header.last-modified' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 102 <!ENTITY header-user-agent "<xref target=' Part2' x:rel='#header.user-agent' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">99 <!ENTITY header-user-agent "<xref target='header.user-agent' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 103 100 <!ENTITY header-vary "<xref target='Part6' x:rel='#header.vary' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 104 101 <!ENTITY message-body "<xref target='Part1' x:rel='#message.body' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 105 102 <!ENTITY multipart-byteranges "<xref target='Part5' x:rel='#internet.media.type.multipart.byteranges' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 106 <!ENTITY http-date "<xref target=' Part2' x:rel='#http.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">103 <!ENTITY http-date "<xref target='http.date' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 107 104 <!ENTITY qvalue "<xref target='Part1' x:rel='#quality.values' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 108 105 <!ENTITY uri "<xref target='Part1' x:rel='#uri' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> … … 113 110 <!ENTITY deflate-coding "<xref target='Part1' x:rel='#deflate.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 114 111 <!ENTITY gzip-coding "<xref target='Part1' x:rel='#gzip.coding' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 115 <!ENTITY response-representation "<xref target=' Part2' x:rel='#identifying.response.associated.with.representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">112 <!ENTITY response-representation "<xref target='identifying.response.associated.with.representation' xmlns:x='http://purl.org/net/xml2rfc/ext'/>"> 116 113 ]> 117 114 <?rfc toc="yes" ?> … … 1830 1827 The resource identified by the request is only capable of generating 1831 1828 response representations which have content characteristics not acceptable 1832 according to the Accept and Accept-* header fields sent in the request 1833 (see &p3-header-fields;). 1829 according to the Accept and Accept-* header fields sent in the request. 1834 1830 </t> 1835 1831 <t> … … 2117 2113 consists of metadata (representation header fields) and data (representation 2118 2114 body). When a complete or partial representation is enclosed in an HTTP message, 2119 it is referred to as the payload of the message. HTTP representations 2120 are defined in &payload;. 2115 it is referred to as the payload of the message. 2121 2116 </t> 2122 2117 <t> … … 3086 3081 <ttcol>Reference</ttcol> 3087 3082 3083 <c>Accept</c> 3084 <c>http</c> 3085 <c>standard</c> 3086 <c> 3087 <xref target="header.accept"/> 3088 </c> 3089 <c>Accept-Charset</c> 3090 <c>http</c> 3091 <c>standard</c> 3092 <c> 3093 <xref target="header.accept-charset"/> 3094 </c> 3095 <c>Accept-Encoding</c> 3096 <c>http</c> 3097 <c>standard</c> 3098 <c> 3099 <xref target="header.accept-encoding"/> 3100 </c> 3101 <c>Accept-Language</c> 3102 <c>http</c> 3103 <c>standard</c> 3104 <c> 3105 <xref target="header.accept-language"/> 3106 </c> 3088 3107 <c>Allow</c> 3089 3108 <c>http</c> … … 3091 3110 <c> 3092 3111 <xref target="header.allow"/> 3112 </c> 3113 <c>Content-Encoding</c> 3114 <c>http</c> 3115 <c>standard</c> 3116 <c> 3117 <xref target="header.content-encoding"/> 3118 </c> 3119 <c>Content-Language</c> 3120 <c>http</c> 3121 <c>standard</c> 3122 <c> 3123 <xref target="header.content-language"/> 3124 </c> 3125 <c>Content-Location</c> 3126 <c>http</c> 3127 <c>standard</c> 3128 <c> 3129 <xref target="header.content-location"/> 3130 </c> 3131 <c>Content-Type</c> 3132 <c>http</c> 3133 <c>standard</c> 3134 <c> 3135 <xref target="header.content-type"/> 3093 3136 </c> 3094 3137 <c>Date</c> … … 3115 3158 <c> 3116 3159 <xref target="header.location"/> 3160 </c> 3161 <c>MIME-Version</c> 3162 <c>http</c> 3163 <c>standard</c> 3164 <c> 3165 <xref target="mime-version"/> 3117 3166 </c> 3118 3167 <c>Max-Forwards</c> … … 3313 3362 </reference> 3314 3363 3315 <reference anchor="Part3">3316 <front>3317 <title abbrev="HTTP/1.1">HTTP/1.1, part 3: Message Payload and Content Negotiation</title>3318 <author initials="R." surname="Fielding" fullname="Roy T. Fielding" role="editor">3319 <organization abbrev="Adobe">Adobe Systems Incorporated</organization>3320 <address><email>fielding@gbiv.com</email></address>3321 </author>3322 <author initials="Y." surname="Lafon" fullname="Yves Lafon" role="editor">3323 <organization abbrev="W3C">World Wide Web Consortium</organization>3324 <address><email>ylafon@w3.org</email></address>3325 </author>3326 <author initials="J. F." surname="Reschke" fullname="Julian F. Reschke" role="editor">3327 <organization abbrev="greenbytes">greenbytes GmbH</organization>3328 <address><email>julian.reschke@greenbytes.de</email></address>3329 </author>3330 <date month="&ID-MONTH;" year="&ID-YEAR;"/>3331 </front>3332 <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p3-payload-&ID-VERSION;"/>3333 <x:source href="p3-payload.xml" basename="p3-payload"/>3334 </reference>3335 3336 3364 <reference anchor="Part4"> 3337 3365 <front> … … 4086 4114 <figure> 4087 4115 <artwork type="abnf" name="p2-semantics.parsed-abnf"> 4116 <x:ref>Accept</x:ref> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [ 4117 OWS media-range [ accept-params ] ] ) ] 4118 <x:ref>Accept-Charset</x:ref> = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q=" 4119 qvalue ] *( OWS "," [ OWS ( charset / "*" ) [ OWS ";" OWS "q=" 4120 qvalue ] ] ) 4121 <x:ref>Accept-Encoding</x:ref> = [ ( "," / ( codings [ OWS ";" OWS "q=" qvalue ] ) ) 4122 *( OWS "," [ OWS codings [ OWS ";" OWS "q=" qvalue ] ] ) ] 4123 <x:ref>Accept-Language</x:ref> = *( "," OWS ) language-range [ OWS ";" OWS "q=" 4124 qvalue ] *( OWS "," [ OWS language-range [ OWS ";" OWS "q=" qvalue ] 4125 ] ) 4088 4126 <x:ref>Allow</x:ref> = [ ( "," / method ) *( OWS "," [ OWS method ] ) ] 4089 4127 4090 4128 <x:ref>BWS</x:ref> = <BWS, defined in [Part1], Section 3.2.1> 4091 4129 4130 <x:ref>Content-Encoding</x:ref> = *( "," OWS ) content-coding *( OWS "," [ OWS 4131 content-coding ] ) 4132 <x:ref>Content-Language</x:ref> = *( "," OWS ) language-tag *( OWS "," [ OWS 4133 language-tag ] ) 4134 <x:ref>Content-Location</x:ref> = absolute-URI / partial-URI 4135 <x:ref>Content-Type</x:ref> = media-type 4136 4092 4137 <x:ref>Date</x:ref> = HTTP-date 4093 4138 … … 4102 4147 <x:ref>Location</x:ref> = URI-reference 4103 4148 4149 <x:ref>MIME-Version</x:ref> = 1*DIGIT "." 1*DIGIT 4150 4104 4151 <x:ref>Max-Forwards</x:ref> = 1*DIGIT 4105 4152 … … 4107 4154 4108 4155 <x:ref>RWS</x:ref> = <RWS, defined in [Part1], Section 3.2.1> 4156 4109 4157 <x:ref>Referer</x:ref> = absolute-URI / partial-URI 4110 4158 <x:ref>Retry-After</x:ref> = HTTP-date / delta-seconds … … 4113 4161 4114 4162 <x:ref>URI-reference</x:ref> = <URI-reference, defined in [Part1], Section 2.7> 4163 4115 4164 <x:ref>User-Agent</x:ref> = product *( RWS ( product / comment ) ) 4116 4165 4117 4166 <x:ref>absolute-URI</x:ref> = <absolute-URI, defined in [Part1], Section 2.7> 4167 4168 <x:ref>accept-ext</x:ref> = OWS ";" OWS token [ "=" word ] 4169 <x:ref>accept-params</x:ref> = OWS ";" OWS "q=" qvalue *accept-ext 4118 4170 <x:ref>asctime-date</x:ref> = day-name SP date3 SP time-of-day SP year 4119 4171 <x:ref>attribute</x:ref> = token 4172 4173 <x:ref>charset</x:ref> = token 4174 4175 <x:ref>codings</x:ref> = content-coding / "identity" / "*" 4120 4176 <x:ref>comment</x:ref> = <comment, defined in [Part1], Section 3.2.4> 4177 <x:ref>content-coding</x:ref> = token 4121 4178 4122 4179 <x:ref>date1</x:ref> = day SP month SP year 4180 4123 4181 <x:ref>date2</x:ref> = day "-" month "-" 2DIGIT 4124 4182 <x:ref>date3</x:ref> = month SP ( 2DIGIT / ( SP DIGIT ) ) … … 4141 4199 4142 4200 <x:ref>expect-name</x:ref> = token 4201 4143 4202 <x:ref>expect-param</x:ref> = expect-name [ BWS "=" BWS expect-value ] 4144 4203 <x:ref>expect-value</x:ref> = token / quoted-string … … 4148 4207 <x:ref>hour</x:ref> = 2DIGIT 4149 4208 4209 <x:ref>language-range</x:ref> = <language-range, defined in [RFC4647], Section 2.1> 4210 4211 <x:ref>language-tag</x:ref> = <Language-Tag, defined in [RFC5646], Section 2.1> 4212 4150 4213 <x:ref>mailbox</x:ref> = <mailbox, defined in [RFC5322], Section 3.4> 4214 4215 <x:ref>media-range</x:ref> = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS 4216 ";" OWS parameter ) 4217 <x:ref>media-type</x:ref> = type "/" subtype *( OWS ";" OWS parameter ) 4151 4218 <x:ref>method</x:ref> = token 4152 4219 <x:ref>minute</x:ref> = 2DIGIT … … 4165 4232 4166 4233 <x:ref>obs-date</x:ref> = rfc850-date / asctime-date 4234 4167 4235 <x:ref>obs-text</x:ref> = <obs-text, defined in [Part1], Section 3.2.4> 4236 4237 <x:ref>parameter</x:ref> = attribute "=" value 4168 4238 4169 4239 <x:ref>partial-URI</x:ref> = <partial-URI, defined in [Part1], Section 2.7> … … 4174 4244 4175 4245 <x:ref>rfc1123-date</x:ref> = day-name "," SP date1 SP time-of-day SP GMT 4246 4176 4247 <x:ref>rfc850-date</x:ref> = day-name-l "," SP date2 SP time-of-day SP GMT 4177 4248 4178 4249 <x:ref>second</x:ref> = 2DIGIT 4179 4250 4251 <x:ref>subtype</x:ref> = token 4252 4180 4253 <x:ref>time-of-day</x:ref> = hour ":" minute ":" second 4254 4181 4255 <x:ref>token</x:ref> = <token, defined in [Part1], Section 3.2.4> 4182 4183 word = <word, defined in [Part1], Section 3.2.4> 4256 <x:ref>type</x:ref> = token 4257 4258 <x:ref>value</x:ref> = word 4259 4260 <x:ref>word</x:ref> = <word, defined in [Part1], Section 3.2.4> 4184 4261 4185 4262 <x:ref>year</x:ref> = 4DIGIT … … 4187 4264 </figure> 4188 4265 <figure><preamble>ABNF diagnostics:</preamble><artwork type="inline"> 4266 ; qvalue UNDEFINED 4267 ; Accept defined but not used 4268 ; Accept-Charset defined but not used 4269 ; Accept-Encoding defined but not used 4270 ; Accept-Language defined but not used 4189 4271 ; Allow defined but not used 4272 ; Content-Encoding defined but not used 4273 ; Content-Language defined but not used 4274 ; Content-Location defined but not used 4275 ; Content-Type defined but not used 4190 4276 ; Date defined but not used 4191 4277 ; Expect defined but not used 4192 4278 ; From defined but not used 4193 4279 ; Location defined but not used 4280 ; MIME-Version defined but not used 4194 4281 ; Max-Forwards defined but not used 4195 4282 ; Referer defined but not used … … 4198 4285 ; User-Agent defined but not used 4199 4286 ; obs-text defined but not used 4200 ; word defined but not used4201 4287 </artwork></figure></section> 4202 4288 <?ENDINC p2-semantics.abnf-appendix ?> … … 4844 4930 </section> 4845 4931 4932 <section title="THE TEXT FORMERLY KNOWN AS PART3"> 4933 <section title="Protocol Parameters" anchor="protocol.parameters"> 4934 4935 <section title="Character Encodings (charset)" anchor="character.sets"> 4936 <t> 4937 HTTP uses charset names to indicate the character encoding of a 4938 textual representation. 4939 </t> 4940 <t anchor="rule.charset"> 4941 <x:anchor-alias value="charset"/> 4942 A character encoding is identified by a case-insensitive token. The 4943 complete set of tokens is defined by the IANA Character Set registry 4944 (<eref target="http://www.iana.org/assignments/character-sets"/>). 4945 </t> 4946 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="charset"/> 4947 <x:ref>charset</x:ref> = <x:ref>token</x:ref> 4948 </artwork></figure> 4949 <t> 4950 Although HTTP allows an arbitrary token to be used as a charset 4951 value, any token that has a predefined value within the IANA 4952 Character Set registry &MUST; represent the character encoding defined 4953 by that registry. Applications &SHOULD; limit their use of character 4954 encodings to those defined within the IANA registry. 4955 </t> 4956 <t> 4957 HTTP uses charset in two contexts: within an Accept-Charset request 4958 header field (in which the charset value is an unquoted token) and as the 4959 value of a parameter in a Content-Type header field (within a request or 4960 response), in which case the parameter value of the charset parameter 4961 can be quoted. 4962 </t> 4963 <t> 4964 Implementors need to be aware of IETF character set requirements <xref target="RFC3629"/> 4965 <xref target="RFC2277"/>. 4966 </t> 4967 </section> 4968 4969 <section title="Content Codings" anchor="content.codings"> 4970 <x:anchor-alias value="content-coding"/> 4971 <t> 4972 Content coding values indicate an encoding transformation that has 4973 been or can be applied to a representation. Content codings are primarily 4974 used to allow a representation to be compressed or otherwise usefully 4975 transformed without losing the identity of its underlying media type 4976 and without loss of information. Frequently, the representation is stored in 4977 coded form, transmitted directly, and only decoded by the recipient. 4978 </t> 4979 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="content-coding"/> 4980 <x:ref>content-coding</x:ref> = <x:ref>token</x:ref> 4981 </artwork></figure> 4982 <t> 4983 All content-coding values are case-insensitive. HTTP/1.1 uses 4984 content-coding values in the Accept-Encoding (<xref target="header.accept-encoding"/>) and 4985 Content-Encoding (<xref target="header.content-encoding"/>) header fields. Although the value 4986 describes the content-coding, what is more important is that it 4987 indicates what decoding mechanism will be required to remove the 4988 encoding. 4989 </t> 4990 <t> 4991 compress<iref item="compress (Coding Format)"/><iref item="Coding Format" subitem="compress"/> 4992 <list> 4993 <t> 4994 See &compress-coding;. 4995 </t> 4996 </list> 4997 </t> 4998 <t> 4999 deflate<iref item="deflate (Coding Format)"/><iref item="Coding Format" subitem="deflate"/> 5000 <list> 5001 <t> 5002 See &deflate-coding;. 5003 </t> 5004 </list> 5005 </t> 5006 <t> 5007 gzip<iref item="gzip (Coding Format)"/><iref item="Coding Format" subitem="gzip"/> 5008 <list> 5009 <t> 5010 See &gzip-coding;. 5011 </t> 5012 </list> 5013 </t> 5014 5015 <section title="Content Coding Registry" anchor="content.coding.registry"> 5016 <t> 5017 The HTTP Content Coding Registry defines the name space for the content 5018 coding names. 5019 </t> 5020 <t> 5021 Registrations &MUST; include the following fields: 5022 <list style="symbols"> 5023 <t>Name</t> 5024 <t>Description</t> 5025 <t>Pointer to specification text</t> 5026 </list> 5027 </t> 5028 <t> 5029 Names of content codings &MUST-NOT; overlap with names of transfer codings 5030 (&transfer-codings;), unless the encoding transformation is identical (as 5031 is the case for the compression codings defined in 5032 &compression-codings;). 5033 </t> 5034 <t> 5035 Values to be added to this name space require IETF Review 5036 (see <xref target="RFC5226" x:fmt="of" x:sec="4.1"/>), and &MUST; 5037 conform to the purpose of content coding defined in this section. 5038 </t> 5039 <t> 5040 The registry itself is maintained at 5041 <eref target="http://www.iana.org/assignments/http-parameters"/>. 5042 </t> 5043 </section> 5044 5045 </section> 5046 5047 <section title="Media Types" anchor="media.types"> 5048 <x:anchor-alias value="media-type"/> 5049 <x:anchor-alias value="type"/> 5050 <x:anchor-alias value="subtype"/> 5051 <t> 5052 HTTP uses Internet Media Types <xref target="RFC2046"/> in the Content-Type (<xref target="header.content-type"/>) 5053 and Accept (<xref target="header.accept"/>) header fields in order to provide 5054 open and extensible data typing and type negotiation. 5055 </t> 5056 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="media-type"/><iref primary="true" item="Grammar" subitem="type"/><iref primary="true" item="Grammar" subitem="subtype"/> 5057 <x:ref>media-type</x:ref> = <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> ) 5058 <x:ref>type</x:ref> = <x:ref>token</x:ref> 5059 <x:ref>subtype</x:ref> = <x:ref>token</x:ref> 5060 </artwork></figure> 5061 <t anchor="rule.parameter"> 5062 <x:anchor-alias value="attribute"/> 5063 <x:anchor-alias value="parameter"/> 5064 <x:anchor-alias value="value"/> 5065 The type/subtype &MAY; be followed by parameters in the form of 5066 attribute/value pairs. 5067 </t> 5068 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="parameter"/><iref primary="true" item="Grammar" subitem="attribute"/><iref primary="true" item="Grammar" subitem="value"/> 5069 <x:ref>parameter</x:ref> = <x:ref>attribute</x:ref> "=" <x:ref>value</x:ref> 5070 <x:ref>attribute</x:ref> = <x:ref>token</x:ref> 5071 <x:ref>value</x:ref> = <x:ref>word</x:ref> 5072 </artwork></figure> 5073 <t> 5074 The type, subtype, and parameter attribute names are case-insensitive. 5075 Parameter values might or might not be case-sensitive, depending on the 5076 semantics of the parameter name. The presence or absence of a parameter might 5077 be significant to the processing of a media-type, depending on its 5078 definition within the media type registry. 5079 </t> 5080 <t> 5081 A parameter value that matches the <x:ref>token</x:ref> production can be 5082 transmitted as either a token or within a quoted-string. The quoted and 5083 unquoted values are equivalent. 5084 </t> 5085 <t> 5086 Note that some older HTTP applications do not recognize media type 5087 parameters. When sending data to older HTTP applications, 5088 implementations &SHOULD; only use media type parameters when they are 5089 required by that type/subtype definition. 5090 </t> 5091 <t> 5092 Media-type values are registered with the Internet Assigned Number 5093 Authority (IANA). The media type registration process is 5094 outlined in <xref target="RFC4288"/>. Use of non-registered media types is 5095 discouraged. 5096 </t> 5097 5098 <section title="Canonicalization and Text Defaults" anchor="canonicalization.and.text.defaults"> 5099 <t> 5100 Internet media types are registered with a canonical form. A 5101 representation transferred via HTTP messages &MUST; be in the 5102 appropriate canonical form prior to its transmission except for 5103 "text" types, as defined in the next paragraph. 5104 </t> 5105 <t> 5106 When in canonical form, media subtypes of the "text" type use CRLF as 5107 the text line break. HTTP relaxes this requirement and allows the 5108 transport of text media with plain CR or LF alone representing a line 5109 break when it is done consistently for an entire representation. HTTP 5110 applications &MUST; accept CRLF, bare CR, and bare LF as indicating 5111 a line break in text media received via HTTP. In 5112 addition, if the text is in a character encoding that does not 5113 use octets 13 and 10 for CR and LF respectively, as is the case for 5114 some multi-byte character encodings, HTTP allows the use of whatever octet 5115 sequences are defined by that character encoding to represent the 5116 equivalent of CR and LF for line breaks. This flexibility regarding 5117 line breaks applies only to text media in the payload body; a bare CR 5118 or LF &MUST-NOT; be substituted for CRLF within any of the HTTP control 5119 structures (such as header fields and multipart boundaries). 5120 </t> 5121 <t> 5122 If a representation is encoded with a content-coding, the underlying 5123 data &MUST; be in a form defined above prior to being encoded. 5124 </t> 5125 </section> 5126 5127 <section title="Multipart Types" anchor="multipart.types"> 5128 <t> 5129 MIME provides for a number of "multipart" types — encapsulations of 5130 one or more representations within a single message body. All multipart 5131 types share a common syntax, as defined in <xref target="RFC2046" x:sec="5.1.1" x:fmt="of"/>, 5132 and &MUST; include a boundary parameter as part of the media type 5133 value. The message body is itself a protocol element and &MUST; 5134 therefore use only CRLF to represent line breaks between body-parts. 5135 </t> 5136 <t> 5137 In general, HTTP treats a multipart message body no differently than 5138 any other media type: strictly as payload. HTTP does not use the 5139 multipart boundary as an indicator of message body length. 5140 <!-- jre: re-insert removed text pointing to caching? --> 5141 In all other respects, an HTTP user agent &SHOULD; follow the same or similar 5142 behavior as a MIME user agent would upon receipt of a multipart type. 5143 The MIME header fields within each body-part of a multipart message body 5144 do not have any significance to HTTP beyond that defined by 5145 their MIME semantics. 5146 </t> 5147 <t> 5148 If an application receives an unrecognized multipart subtype, the 5149 application &MUST; treat it as being equivalent to "multipart/mixed". 5150 </t> 5151 <x:note> 5152 <t> 5153 <x:h>Note:</x:h> The "multipart/form-data" type has been specifically defined 5154 for carrying form data suitable for processing via the POST 5155 request method, as described in <xref target="RFC2388"/>. 5156 </t> 5157 </x:note> 5158 </section> 5159 </section> 5160 5161 <section title="Language Tags" anchor="language.tags"> 5162 <x:anchor-alias value="language-tag"/> 5163 <t> 5164 A language tag, as defined in <xref target="RFC5646"/>, identifies a 5165 natural language spoken, written, or otherwise conveyed by human beings for 5166 communication of information to other human beings. Computer languages are 5167 explicitly excluded. HTTP uses language tags within the Accept-Language and 5168 Content-Language fields. 5169 </t> 5170 <t> 5171 In summary, a language tag is composed of one or more parts: A primary 5172 language subtag followed by a possibly empty series of subtags: 5173 </t> 5174 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="language-tag"/> 5175 <x:ref>language-tag</x:ref> = <Language-Tag, defined in <xref target="RFC5646" x:sec="2.1"/>> 5176 </artwork></figure> 5177 <t> 5178 White space is not allowed within the tag and all tags are case-insensitive. 5179 The name space of language subtags is administered by the IANA (see 5180 <eref target="http://www.iana.org/assignments/language-subtag-registry"/>). 5181 </t> 5182 <figure> 5183 <preamble>Example tags include:</preamble> 5184 <artwork type="example"> 5185 en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN 5186 </artwork> 5187 </figure> 5188 <t> 5189 See <xref target="RFC5646"/> for further information. 5190 </t> 5191 </section> 5192 </section> 5193 5194 <section title="Payload" anchor="payload"> 5195 <t> 5196 HTTP messages &MAY; transfer a payload if not otherwise restricted by 5197 the request method or response status code. The payload consists of 5198 metadata, in the form of header fields, and data, in the form of the 5199 sequence of octets in the message body after any transfer-coding has 5200 been decoded. 5201 </t> 5202 <iref item="payload"/> 5203 <t> 5204 A "<x:dfn>payload</x:dfn>" in HTTP is always a partial or complete 5205 representation of some resource. We use separate terms for payload 5206 and representation because some messages contain only the associated 5207 representation's header fields (e.g., responses to HEAD) or only some 5208 part(s) of the representation (e.g., the 206 status code). 5209 </t> 5210 <section title="Payload Header Fields" anchor="payload.header.fields"> 5211 <x:anchor-alias value="payload-header"/> 5212 <t> 5213 HTTP header fields that specifically define the payload, rather than the 5214 associated representation, are referred to as "payload header fields". 5215 The following payload header fields are defined by HTTP/1.1: 5216 </t> 5217 <texttable align="left"> 5218 <ttcol>Header Field Name</ttcol> 5219 <ttcol>Defined in...</ttcol> 5220 5221 <c>Content-Length</c> <c>&header-content-length;</c> 5222 <c>Content-Range</c> <c>&header-content-range;</c> 5223 </texttable> 5224 </section> 5225 5226 <section title="Payload Body" anchor="payload.body"> 5227 <x:anchor-alias value="payload-body"/> 5228 <t> 5229 A payload body is only present in a message when a message body is 5230 present, as described in &message-body;. The payload body is obtained 5231 from the message body by decoding any Transfer-Encoding that might 5232 have been applied to ensure safe and proper transfer of the message. 5233 </t> 5234 </section> 5235 </section> 5236 5237 <section title="Representation" anchor="representation3"> 5238 <iref item="representation"/> 5239 <t> 5240 A "<x:dfn>representation</x:dfn>" is information in a format that can be readily 5241 communicated from one party to another. A resource representation 5242 is information that reflects the state of that resource, as observed 5243 at some point in the past (e.g., in a response to GET) or to be 5244 desired at some point in the future (e.g., in a PUT request). 5245 </t> 5246 <t> 5247 Most, but not all, representations transferred via HTTP are intended 5248 to be a representation of the target resource (the resource identified 5249 by the effective request URI). The precise semantics of a representation 5250 are determined by the type of message (request or response), the request 5251 method, the response status code, and the representation metadata. 5252 For example, the above semantic is true for the representation in any 5253 200 (OK) response to GET and for the representation in any PUT request. 5254 A 200 response to PUT, in contrast, contains either a representation 5255 that describes the successful action or a representation of the target 5256 resource, with the latter indicated by a Content-Location header field 5257 with the same value as the effective request URI. Likewise, response 5258 messages with an error status code usually contain a representation that 5259 describes the error and what next steps are suggested for resolving it. 5260 </t> 5261 5262 <section title="Representation Header Fields" anchor="representation.header.fields"> 5263 <x:anchor-alias value="representation-header"/> 5264 <t> 5265 Representation header fields define metadata about the representation data 5266 enclosed in the message body or, if no message body is present, about 5267 the representation that would have been transferred in a 200 response 5268 to a simultaneous GET request with the same effective request URI. 5269 </t> 5270 <t> 5271 The following header fields are defined as representation metadata: 5272 </t> 5273 <texttable align="left"> 5274 <ttcol>Header Field Name</ttcol> 5275 <ttcol>Defined in...</ttcol> 5276 5277 <c>Content-Encoding</c> <c><xref target="header.content-encoding"/></c> 5278 <c>Content-Language</c> <c><xref target="header.content-language"/></c> 5279 <c>Content-Location</c> <c><xref target="header.content-location"/></c> 5280 <c>Content-Type</c> <c><xref target="header.content-type"/></c> 5281 <c>Expires</c> <c>&header-expires;</c> 5282 </texttable> 5283 <t> 5284 Additional header fields define metadata about the selected 5285 representation, which might differ from the representation included 5286 in the message for responses to some state-changing methods. 5287 The following header fields are defined as selected representation 5288 metadata: 5289 </t> 5290 <texttable align="left"> 5291 <ttcol>Header Field Name</ttcol> 5292 <ttcol>Defined in...</ttcol> 5293 5294 <c>ETag</c> <c>&header-etag;</c> 5295 <c>Last-Modified</c> <c>&header-last-modified;</c> 5296 </texttable> 5297 </section> 5298 5299 <section title="Representation Data" anchor="representation.data"> 5300 <x:anchor-alias value="representation-data"/> 5301 <t> 5302 The representation body associated with an HTTP message is 5303 either provided as the payload body of the message or 5304 referred to by the message semantics and the effective request 5305 URI. The representation data is in a format and encoding defined by 5306 the representation metadata header fields. 5307 </t> 5308 <t> 5309 The data type of the representation data 5310 is determined via the header fields Content-Type and Content-Encoding. 5311 These define a two-layer, ordered encoding model: 5312 </t> 5313 <figure><artwork type="example"> 5314 representation-data := Content-Encoding( Content-Type( bits ) ) 5315 </artwork></figure> 5316 <t> 5317 Content-Type specifies the media type of the underlying data, which 5318 defines both the data format and how that data &SHOULD; be processed 5319 by the recipient (within the scope of the request method semantics). 5320 Any HTTP/1.1 message containing a payload body &SHOULD; include a 5321 Content-Type header field defining the media type of the associated 5322 representation unless that metadata is unknown to the sender. 5323 If the Content-Type header field is not present, it indicates that 5324 the sender does not know the media type of the representation; 5325 recipients &MAY; either assume that the media type is 5326 "application/octet-stream" (<xref target="RFC2046" x:fmt="," x:sec="4.5.1"/>) 5327 or examine the content to determine its type. 5328 </t> 5329 <t> 5330 In practice, resource owners do not always properly configure their origin 5331 server to provide the correct Content-Type for a given representation, 5332 with the result that some clients will examine a response body's content 5333 and override the specified type. 5334 Clients that do so risk drawing incorrect conclusions, which might expose 5335 additional security risks (e.g., "privilege escalation"). Furthermore, 5336 it is impossible to determine the sender's intent by examining the data 5337 format: many data formats match multiple media types that differ only in 5338 processing semantics. Implementers are encouraged to provide a means of 5339 disabling such "content sniffing" when it is used. 5340 </t> 5341 <t> 5342 Content-Encoding is used to indicate any additional content 5343 codings applied to the data, usually for the purpose of data 5344 compression, that are a property of the representation. If 5345 Content-Encoding is not present, then there is no additional 5346 encoding beyond that defined by the Content-Type. 5347 </t> 5348 </section> 5349 </section> 5350 5351 <section title="Content Negotiation" anchor="content.negotiation"> 5352 <t> 5353 HTTP responses include a representation which contains information for 5354 interpretation, whether by a human user or for further processing. 5355 Often, the server has different ways of representing the 5356 same information; for example, in different formats, languages, 5357 or using different character encodings. 5358 </t> 5359 <t> 5360 HTTP clients and their users might have different or variable 5361 capabilities, characteristics or preferences which would influence 5362 which representation, among those available from the server, 5363 would be best for the server to deliver. For this reason, HTTP 5364 provides mechanisms for "content negotiation" — a process of 5365 allowing selection of a representation of a given resource, 5366 when more than one is available. 5367 </t> 5368 <t> 5369 This specification defines two patterns of content negotiation; 5370 "server-driven", where the server selects the representation based 5371 upon the client's stated preferences, and "agent-driven" negotiation, 5372 where the server provides a list of representations for the client to 5373 choose from, based upon their metadata. In addition, there are 5374 other patterns: some applications use an "active content" pattern, 5375 where the server returns active content which runs on the client 5376 and, based on client available parameters, selects additional 5377 resources to invoke. "Transparent Content Negotiation" (<xref target="RFC2295"/>) 5378 has also been proposed. 5379 </t> 5380 <t> 5381 These patterns are all widely used, and have trade-offs in applicability 5382 and practicality. In particular, when the number of preferences or 5383 capabilities to be expressed by a client are large (such as when many 5384 different formats are supported by a user-agent), server-driven 5385 negotiation becomes unwieldy, and might not be appropriate. Conversely, 5386 when the number of representations to choose from is very large, 5387 agent-driven negotiation might not be appropriate. 5388 </t> 5389 <t> 5390 Note that in all cases, the supplier of representations has the 5391 responsibility for determining which representations might be 5392 considered to be the "same information". 5393 </t> 5394 5395 <section title="Server-driven Negotiation" anchor="server-driven.negotiation"> 5396 <t> 5397 If the selection of the best representation for a response is made by 5398 an algorithm located at the server, it is called server-driven 5399 negotiation. Selection is based on the available representations of 5400 the response (the dimensions over which it can vary; e.g., language, 5401 content-coding, etc.) and the contents of particular header fields in 5402 the request message or on other information pertaining to the request 5403 (such as the network address of the client). 5404 </t> 5405 <t> 5406 Server-driven negotiation is advantageous when the algorithm for 5407 selecting from among the available representations is difficult to 5408 describe to the user agent, or when the server desires to send its 5409 "best guess" to the client along with the first response (hoping to 5410 avoid the round-trip delay of a subsequent request if the "best 5411 guess" is good enough for the user). In order to improve the server's 5412 guess, the user agent &MAY; include request header fields (Accept, 5413 Accept-Language, Accept-Encoding, etc.) which describe its 5414 preferences for such a response. 5415 </t> 5416 <t> 5417 Server-driven negotiation has disadvantages: 5418 <list style="numbers"> 5419 <t> 5420 It is impossible for the server to accurately determine what 5421 might be "best" for any given user, since that would require 5422 complete knowledge of both the capabilities of the user agent 5423 and the intended use for the response (e.g., does the user want 5424 to view it on screen or print it on paper?). 5425 </t> 5426 <t> 5427 Having the user agent describe its capabilities in every 5428 request can be both very inefficient (given that only a small 5429 percentage of responses have multiple representations) and a 5430 potential violation of the user's privacy. 5431 </t> 5432 <t> 5433 It complicates the implementation of an origin server and the 5434 algorithms for generating responses to a request. 5435 </t> 5436 <t> 5437 It might limit a public cache's ability to use the same response 5438 for multiple user's requests. 5439 </t> 5440 </list> 5441 </t> 5442 <t> 5443 Server-driven negotiation allows the user agent to specify its preferences, 5444 but it cannot expect responses to always honor them. For example, the origin 5445 server might not implement server-driven negotiation, or it might decide that 5446 sending a response that doesn't conform to them is better than sending a 406 5447 (Not Acceptable) response. 5448 </t> 5449 <t> 5450 Many of the mechanisms for expressing preferences use quality values to 5451 declare relative preference. See &qvalue; for more information. 5452 </t> 5453 <t> 5454 HTTP/1.1 includes the following header fields for enabling 5455 server-driven negotiation through description of user agent 5456 capabilities and user preferences: Accept (<xref target="header.accept"/>), Accept-Charset 5457 (<xref target="header.accept-charset"/>), Accept-Encoding (<xref target="header.accept-encoding"/>), Accept-Language 5458 (<xref target="header.accept-language"/>), and User-Agent (&header-user-agent;). 5459 However, an origin server is not limited to these dimensions and &MAY; vary 5460 the response based on any aspect of the request, including aspects 5461 of the connection (e.g., IP address) or information within extension 5462 header fields not defined by this specification. 5463 </t> 5464 <x:note> 5465 <t> 5466 <x:h>Note:</x:h> In practice, User-Agent based negotiation is fragile, 5467 because new clients might not be recognized. 5468 </t> 5469 </x:note> 5470 <t> 5471 The Vary header field (&header-vary;) can be used to express the parameters the 5472 server uses to select a representation that is subject to server-driven 5473 negotiation. 5474 </t> 5475 </section> 5476 5477 <section title="Agent-driven Negotiation" anchor="agent-driven.negotiation"> 5478 <t> 5479 With agent-driven negotiation, selection of the best representation 5480 for a response is performed by the user agent after receiving an 5481 initial response from the origin server. Selection is based on a list 5482 of the available representations of the response included within the 5483 header fields or body of the initial response, with each 5484 representation identified by its own URI. Selection from among the 5485 representations can be performed automatically (if the user agent is 5486 capable of doing so) or manually by the user selecting from a 5487 generated (possibly hypertext) menu. 5488 </t> 5489 <t> 5490 Agent-driven negotiation is advantageous when the response would vary 5491 over commonly-used dimensions (such as type, language, or encoding), 5492 when the origin server is unable to determine a user agent's 5493 capabilities from examining the request, and generally when public 5494 caches are used to distribute server load and reduce network usage. 5495 </t> 5496 <t> 5497 Agent-driven negotiation suffers from the disadvantage of needing a 5498 second request to obtain the best alternate representation. This 5499 second request is only efficient when caching is used. In addition, 5500 this specification does not define any mechanism for supporting 5501 automatic selection, though it also does not prevent any such 5502 mechanism from being developed as an extension and used within 5503 HTTP/1.1. 5504 </t> 5505 <t> 5506 This specification defines the 300 (Multiple Choices) and 406 (Not Acceptable) 5507 status codes for enabling agent-driven negotiation when the server is 5508 unwilling or unable to provide a varying response using server-driven 5509 negotiation. 5510 </t> 5511 </section> 5512 </section> 5513 5514 <section title="Header Field Definitions" anchor="header.field.definitions3"> 5515 <t> 5516 This section defines the syntax and semantics of HTTP/1.1 header fields 5517 related to the payload of messages. 5518 </t> 5519 5520 <section title="Accept" anchor="header.accept"> 5521 <iref primary="true" item="Accept header field" x:for-anchor=""/> 5522 <iref primary="true" item="Header Fields" subitem="Accept" x:for-anchor=""/> 5523 <x:anchor-alias value="Accept"/> 5524 <x:anchor-alias value="accept-ext"/> 5525 <x:anchor-alias value="accept-params"/> 5526 <x:anchor-alias value="media-range"/> 5527 <t> 5528 The "Accept" header field can be used by user agents to specify 5529 response media types that are acceptable. Accept header fields can be used to 5530 indicate that the request is specifically limited to a small set of desired 5531 types, as in the case of a request for an in-line image. 5532 </t> 5533 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept"/><iref primary="true" item="Grammar" subitem="media-range"/><iref primary="true" item="Grammar" subitem="accept-params"/><iref primary="true" item="Grammar" subitem="accept-ext"/> 5534 <x:ref>Accept</x:ref> = #( <x:ref>media-range</x:ref> [ <x:ref>accept-params</x:ref> ] ) 5535 5536 <x:ref>media-range</x:ref> = ( "*/*" 5537 / ( <x:ref>type</x:ref> "/" "*" ) 5538 / ( <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> ) 5539 ) *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> ) 5540 <x:ref>accept-params</x:ref> = <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> *( <x:ref>accept-ext</x:ref> ) 5541 <x:ref>accept-ext</x:ref> = <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>token</x:ref> [ "=" <x:ref>word</x:ref> ] 5542 </artwork></figure> 5543 <t> 5544 The asterisk "*" character is used to group media types into ranges, 5545 with "*/*" indicating all media types and "type/*" indicating all 5546 subtypes of that type. The media-range &MAY; include media type 5547 parameters that are applicable to that range. 5548 </t> 5549 <t> 5550 Each media-range &MAY; be followed by one or more accept-params, 5551 beginning with the "q" parameter for indicating a relative quality 5552 factor. The first "q" parameter (if any) separates the media-range 5553 parameter(s) from the accept-params. Quality factors allow the user 5554 or user agent to indicate the relative degree of preference for that 5555 media-range, using the qvalue scale from 0 to 1 (&qvalue;). The 5556 default value is q=1. 5557 </t> 5558 <x:note> 5559 <t> 5560 <x:h>Note:</x:h> Use of the "q" parameter name to separate media type 5561 parameters from Accept extension parameters is due to historical 5562 practice. Although this prevents any media type parameter named 5563 "q" from being used with a media range, such an event is believed 5564 to be unlikely given the lack of any "q" parameters in the IANA 5565 media type registry and the rare usage of any media type 5566 parameters in Accept. Future media types are discouraged from 5567 registering any parameter named "q". 5568 </t> 5569 </x:note> 5570 <t> 5571 The example 5572 </t> 5573 <figure><artwork type="example"> 5574 Accept: audio/*; q=0.2, audio/basic 5575 </artwork></figure> 5576 <t> 5577 &SHOULD; be interpreted as "I prefer audio/basic, but send me any audio 5578 type if it is the best available after an 80% mark-down in quality". 5579 </t> 5580 <t> 5581 A request without any Accept header field implies that the user agent 5582 will accept any media type in response. 5583 If an Accept header field is present in a request and none of the 5584 available representations for the response have a media type that is 5585 listed as acceptable, the origin server &MAY; either 5586 honor the Accept header field by sending a 406 (Not Acceptable) response 5587 or disregard the Accept header field by treating the response as if 5588 it is not subject to content negotiation. 5589 </t> 5590 <t> 5591 A more elaborate example is 5592 </t> 5593 <figure><artwork type="example"> 5594 Accept: text/plain; q=0.5, text/html, 5595 text/x-dvi; q=0.8, text/x-c 5596 </artwork></figure> 5597 <t> 5598 Verbally, this would be interpreted as "text/html and text/x-c are 5599 the preferred media types, but if they do not exist, then send the 5600 text/x-dvi representation, and if that does not exist, send the text/plain 5601 representation". 5602 </t> 5603 <t> 5604 Media ranges can be overridden by more specific media ranges or 5605 specific media types. If more than one media range applies to a given 5606 type, the most specific reference has precedence. For example, 5607 </t> 5608 <figure><artwork type="example"> 5609 Accept: text/*, text/plain, text/plain;format=flowed, */* 5610 </artwork></figure> 5611 <t> 5612 have the following precedence: 5613 <list style="numbers"> 5614 <t>text/plain;format=flowed</t> 5615 <t>text/plain</t> 5616 <t>text/*</t> 5617 <t>*/*</t> 5618 </list> 5619 </t> 5620 <t> 5621 The media type quality factor associated with a given type is 5622 determined by finding the media range with the highest precedence 5623 which matches that type. For example, 5624 </t> 5625 <figure><artwork type="example"> 5626 Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1, 5627 text/html;level=2;q=0.4, */*;q=0.5 5628 </artwork></figure> 5629 <t> 5630 would cause the following values to be associated: 5631 </t> 5632 <texttable align="left"> 5633 <ttcol>Media Type</ttcol><ttcol>Quality Value</ttcol> 5634 <c>text/html;level=1</c> <c>1</c> 5635 <c>text/html</c> <c>0.7</c> 5636 <c>text/plain</c> <c>0.3</c> 5637 <c>image/jpeg</c> <c>0.5</c> 5638 <c>text/html;level=2</c> <c>0.4</c> 5639 <c>text/html;level=3</c> <c>0.7</c> 5640 </texttable> 5641 <t> 5642 <x:h>Note:</x:h> A user agent might be provided with a default set of quality 5643 values for certain media ranges. However, unless the user agent is 5644 a closed system which cannot interact with other rendering agents, 5645 this default set ought to be configurable by the user. 5646 </t> 5647 </section> 5648 5649 <section title="Accept-Charset" anchor="header.accept-charset"> 5650 <iref primary="true" item="Accept-Charset header field" x:for-anchor=""/> 5651 <iref primary="true" item="Header Fields" subitem="Accept-Charset" x:for-anchor=""/> 5652 <x:anchor-alias value="Accept-Charset"/> 5653 <t> 5654 The "Accept-Charset" header field can be used by user agents to 5655 indicate what character encodings are acceptable in a response 5656 payload. This field allows 5657 clients capable of understanding more comprehensive or special-purpose 5658 character encodings to signal that capability to a server which is capable of 5659 representing documents in those character encodings. 5660 </t> 5661 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Charset"/> 5662 <x:ref>Accept-Charset</x:ref> = 1#( ( <x:ref>charset</x:ref> / "*" ) 5663 [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] ) 5664 </artwork></figure> 5665 <t> 5666 Character encoding values (a.k.a., charsets) are described in 5667 <xref target="character.sets"/>. Each charset &MAY; be given an 5668 associated quality value which represents the user's preference 5669 for that charset. The default value is q=1. An example is 5670 </t> 5671 <figure><artwork type="example"> 5672 Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 5673 </artwork></figure> 5674 <t> 5675 The special value "*", if present in the Accept-Charset field, 5676 matches every character encoding which is not mentioned elsewhere in the 5677 Accept-Charset field. If no "*" is present in an Accept-Charset field, then 5678 all character encodings not explicitly mentioned get a quality value of 0. 5679 </t> 5680 <t> 5681 A request without any Accept-Charset header field implies that the user 5682 agent will accept any character encoding in response. 5683 If an Accept-Charset header field is present in a request and none of the 5684 available representations for the response have a character encoding that 5685 is listed as acceptable, the origin server &MAY; either honor the 5686 Accept-Charset header field by sending a 406 (Not Acceptable) response or 5687 disregard the Accept-Charset header field by treating the response as if 5688 it is not subject to content negotiation. 5689 </t> 5690 </section> 5691 5692 <section title="Accept-Encoding" anchor="header.accept-encoding"> 5693 <iref primary="true" item="Accept-Encoding header field" x:for-anchor=""/> 5694 <iref primary="true" item="Header Fields" subitem="Accept-Encoding" x:for-anchor=""/> 5695 <x:anchor-alias value="Accept-Encoding"/> 5696 <x:anchor-alias value="codings"/> 5697 <t> 5698 The "Accept-Encoding" header field can be used by user agents to 5699 indicate what response content-codings (<xref target="content.codings"/>) 5700 are acceptable in the response. An "identity" token is used as a synonym 5701 for "no encoding" in order to communicate when no encoding is preferred. 5702 </t> 5703 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Encoding"/><iref primary="true" item="Grammar" subitem="codings"/> 5704 <x:ref>Accept-Encoding</x:ref> = #( <x:ref>codings</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] ) 5705 <x:ref>codings</x:ref> = <x:ref>content-coding</x:ref> / "identity" / "*" 5706 </artwork></figure> 5707 <t> 5708 Each codings value &MAY; be given an associated quality value which 5709 represents the preference for that encoding. The default value is q=1. 5710 </t> 5711 <t> 5712 For example, 5713 </t> 5714 <figure><artwork type="example"> 5715 Accept-Encoding: compress, gzip 5716 Accept-Encoding: 5717 Accept-Encoding: * 5718 Accept-Encoding: compress;q=0.5, gzip;q=1.0 5719 Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 5720 </artwork></figure> 5721 <t> 5722 A server tests whether a content-coding for a given representation is 5723 acceptable, according to an Accept-Encoding field, using these rules: 5724 <list style="numbers"> 5725 <t>The special "*" symbol in an Accept-Encoding field matches any 5726 available content-coding not explicitly listed in the header 5727 field.</t> 5728 5729 <t>If the representation has no content-coding, then it is acceptable 5730 by default unless specifically excluded by the Accept-Encoding field 5731 stating either "identity;q=0" or "*;q=0" without a more specific 5732 entry for "identity".</t> 5733 5734 <t>If the representation's content-coding is one of the content-codings 5735 listed in the Accept-Encoding field, then it is acceptable unless 5736 it is accompanied by a qvalue of 0. (As defined in &qvalue;, a 5737 qvalue of 0 means "not acceptable".)</t> 5738 5739 <t>If multiple content-codings are acceptable, then the acceptable 5740 content-coding with the highest non-zero qvalue is preferred.</t> 5741 </list> 5742 </t> 5743 <t> 5744 An Accept-Encoding header field with a combined field-value that is empty 5745 implies that the user agent does not want any content-coding in response. 5746 If an Accept-Encoding header field is present in a request and none of the 5747 available representations for the response have a content-coding that 5748 is listed as acceptable, the origin server &SHOULD; send a response 5749 without any content-coding. 5750 </t> 5751 <t> 5752 A request without an Accept-Encoding header field implies that the user 5753 agent will accept any content-coding in response, but a representation 5754 without content-coding is preferred for compatibility with the widest 5755 variety of user agents. 5756 </t> 5757 <x:note> 5758 <t> 5759 <x:h>Note:</x:h> Most HTTP/1.0 applications do not recognize or obey qvalues 5760 associated with content-codings. This means that qvalues will not 5761 work and are not permitted with x-gzip or x-compress. 5762 </t> 5763 </x:note> 5764 </section> 5765 5766 <section title="Accept-Language" anchor="header.accept-language"> 5767 <iref primary="true" item="Accept-Language header field" x:for-anchor=""/> 5768 <iref primary="true" item="Header Fields" subitem="Accept-Language" x:for-anchor=""/> 5769 <x:anchor-alias value="Accept-Language"/> 5770 <x:anchor-alias value="language-range"/> 5771 <t> 5772 The "Accept-Language" header field can be used by user agents to 5773 indicate the set of natural languages that are preferred in the response. 5774 Language tags are defined in <xref target="language.tags"/>. 5775 </t> 5776 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Language"/><iref primary="true" item="Grammar" subitem="language-range"/> 5777 <x:ref>Accept-Language</x:ref> = 5778 1#( <x:ref>language-range</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] ) 5779 <x:ref>language-range</x:ref> = 5780 <language-range, defined in <xref target="RFC4647" x:fmt="," x:sec="2.1"/>> 5781 </artwork></figure> 5782 <t> 5783 Each language-range can be given an associated quality value which 5784 represents an estimate of the user's preference for the languages 5785 specified by that range. The quality value defaults to "q=1". For 5786 example, 5787 </t> 5788 <figure><artwork type="example"> 5789 Accept-Language: da, en-gb;q=0.8, en;q=0.7 5790 </artwork></figure> 5791 <t> 5792 would mean: "I prefer Danish, but will accept British English and 5793 other types of English". 5794 (see also <xref target="RFC4647" x:sec="2.3" x:fmt="of"/>) 5795 </t> 5796 <t> 5797 For matching, <xref target="RFC4647" x:sec="3" x:fmt="of"/> defines 5798 several matching schemes. Implementations can offer the most appropriate 5799 matching scheme for their requirements. 5800 </t> 5801 <x:note> 5802 <t> 5803 <x:h>Note:</x:h> The "Basic Filtering" scheme (<xref target="RFC4647" 5804 x:fmt="," x:sec="3.3.1"/>) is identical to the matching scheme that was 5805 previously defined in <xref target="RFC2616" x:fmt="of" x:sec="14.4"/>. 5806 </t> 5807 </x:note> 5808 <t> 5809 It might be contrary to the privacy expectations of the user to send 5810 an Accept-Language header field with the complete linguistic preferences of 5811 the user in every request. For a discussion of this issue, see 5812 <xref target="privacy.issues.connected.to.accept.header.fields"/>. 5813 </t> 5814 <t> 5815 As intelligibility is highly dependent on the individual user, it is 5816 recommended that client applications make the choice of linguistic 5817 preference available to the user. If the choice is not made 5818 available, then the Accept-Language header field &MUST-NOT; be given in 5819 the request. 5820 </t> 5821 <x:note> 5822 <t> 5823 <x:h>Note:</x:h> When making the choice of linguistic preference available to 5824 the user, we remind implementors of the fact that users are not 5825 familiar with the details of language matching as described above, 5826 and ought to be provided appropriate guidance. As an example, users 5827 might assume that on selecting "en-gb", they will be served any 5828 kind of English document if British English is not available. A 5829 user agent might suggest in such a case to add "en" to get the 5830 best matching behavior. 5831 </t> 5832 </x:note> 5833 </section> 5834 5835 <section title="Content-Encoding" anchor="header.content-encoding"> 5836 <iref primary="true" item="Content-Encoding header field" x:for-anchor=""/> 5837 <iref primary="true" item="Header Fields" subitem="Content-Encoding" x:for-anchor=""/> 5838 <x:anchor-alias value="Content-Encoding"/> 5839 <t> 5840 The "Content-Encoding" header field indicates what content-codings 5841 have been applied to the representation beyond those inherent in the media 5842 type, and thus what decoding mechanisms have to be applied in order to obtain 5843 the media-type referenced by the Content-Type header field. 5844 Content-Encoding is primarily used to allow a representation to be 5845 compressed without losing the identity of its underlying media type. 5846 </t> 5847 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Encoding"/> 5848 <x:ref>Content-Encoding</x:ref> = 1#<x:ref>content-coding</x:ref> 5849 </artwork></figure> 5850 <t> 5851 Content codings are defined in <xref target="content.codings"/>. An example of its use is 5852 </t> 5853 <figure><artwork type="example"> 5854 Content-Encoding: gzip 5855 </artwork></figure> 5856 <t> 5857 The content-coding is a characteristic of the representation. 5858 Typically, the representation body is stored with this 5859 encoding and is only decoded before rendering or analogous usage. 5860 However, a transforming proxy &MAY; modify the content-coding if the 5861 new coding is known to be acceptable to the recipient, unless the 5862 "no-transform" cache-control directive is present in the message. 5863 </t> 5864 <t> 5865 If the media type includes an inherent encoding, such as a data format 5866 that is always compressed, then that encoding would not be restated as 5867 a Content-Encoding even if it happens to be the same algorithm as one 5868 of the content-codings. Such a content-coding would only be listed if, 5869 for some bizarre reason, it is applied a second time to form the 5870 representation. Likewise, an origin server might choose to publish the 5871 same payload data as multiple representations that differ only in whether 5872 the coding is defined as part of Content-Type or Content-Encoding, since 5873 some user agents will behave differently in their handling of each 5874 response (e.g., open a "Save as ..." dialog instead of automatic 5875 decompression and rendering of content). 5876 </t> 5877 <t> 5878 A representation that has a content-coding applied to it &MUST; include 5879 a Content-Encoding header field (<xref target="header.content-encoding"/>) 5880 that lists the content-coding(s) applied. 5881 </t> 5882 <t> 5883 If multiple encodings have been applied to a representation, the content 5884 codings &MUST; be listed in the order in which they were applied. 5885 Additional information about the encoding parameters &MAY; be provided 5886 by other header fields not defined by this specification. 5887 </t> 5888 <t> 5889 If the content-coding of a representation in a request message is not 5890 acceptable to the origin server, the server &SHOULD; respond with a 5891 status code of 415 (Unsupported Media Type). 5892 </t> 5893 </section> 5894 5895 <section title="Content-Language" anchor="header.content-language"> 5896 <iref primary="true" item="Content-Language header field" x:for-anchor=""/> 5897 <iref primary="true" item="Header Fields" subitem="Content-Language" x:for-anchor=""/> 5898 <x:anchor-alias value="Content-Language"/> 5899 <t> 5900 The "Content-Language" header field describes the natural 5901 language(s) of the intended audience for the representation. Note that this might 5902 not be equivalent to all the languages used within the representation. 5903 </t> 5904 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Language"/> 5905 <x:ref>Content-Language</x:ref> = 1#<x:ref>language-tag</x:ref> 5906 </artwork></figure> 5907 <t> 5908 Language tags are defined in <xref target="language.tags"/>. The primary purpose of 5909 Content-Language is to allow a user to identify and differentiate 5910 representations according to the user's own preferred language. Thus, if the 5911 body content is intended only for a Danish-literate audience, the 5912 appropriate field is 5913 </t> 5914 <figure><artwork type="example"> 5915 Content-Language: da 5916 </artwork></figure> 5917 <t> 5918 If no Content-Language is specified, the default is that the content 5919 is intended for all language audiences. This might mean that the 5920 sender does not consider it to be specific to any natural language, 5921 or that the sender does not know for which language it is intended. 5922 </t> 5923 <t> 5924 Multiple languages &MAY; be listed for content that is intended for 5925 multiple audiences. For example, a rendition of the "Treaty of 5926 Waitangi", presented simultaneously in the original Maori and English 5927 versions, would call for 5928 </t> 5929 <figure><artwork type="example"> 5930 Content-Language: mi, en 5931 </artwork></figure> 5932 <t> 5933 However, just because multiple languages are present within a representation 5934 does not mean that it is intended for multiple linguistic audiences. 5935 An example would be a beginner's language primer, such as "A First 5936 Lesson in Latin", which is clearly intended to be used by an 5937 English-literate audience. In this case, the Content-Language would 5938 properly only include "en". 5939 </t> 5940 <t> 5941 Content-Language &MAY; be applied to any media type — it is not 5942 limited to textual documents. 5943 </t> 5944 </section> 5945 5946 <section title="Content-Location" anchor="header.content-location"> 5947 <iref primary="true" item="Content-Location header field" x:for-anchor=""/> 5948 <iref primary="true" item="Header Fields" subitem="Content-Location" x:for-anchor=""/> 5949 <x:anchor-alias value="Content-Location"/> 5950 <t> 5951 The "Content-Location" header field supplies a URI that can be used 5952 as a specific identifier for the representation in this message. 5953 In other words, if one were to perform a GET on this URI at the time 5954 of this message's generation, then a 200 response would contain the 5955 same representation that is enclosed as payload in this message. 5956 </t> 5957 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Location"/> 5958 <x:ref>Content-Location</x:ref> = <x:ref>absolute-URI</x:ref> / <x:ref>partial-URI</x:ref> 5959 </artwork></figure> 5960 <t> 5961 The Content-Location value is not a replacement for the effective 5962 Request URI (&effective-request-uri;). It is representation metadata. 5963 It has the same syntax and semantics as the header field of the same name 5964 defined for MIME body parts in <xref target="RFC2557" x:fmt="of" x:sec="4"/>. 5965 However, its appearance in an HTTP message has some special implications 5966 for HTTP recipients. 5967 </t> 5968 <t> 5969 If Content-Location is included in a response message and its value 5970 is the same as the effective request URI, then the response payload 5971 &SHOULD; be considered a current representation of that resource. 5972 For a GET or HEAD request, this is the same as the default semantics 5973 when no Content-Location is provided by the server. For a state-changing 5974 request like PUT or POST, it implies that the server's response contains 5975 the new representation of that resource, thereby distinguishing it from 5976 representations that might only report about the action (e.g., "It worked!"). 5977 This allows authoring applications to update their local copies without 5978 the need for a subsequent GET request. 5979 </t> 5980 <t> 5981 If Content-Location is included in a response message and its value 5982 differs from the effective request URI, then the origin server is 5983 informing recipients that this representation has its own, presumably 5984 more specific, identifier. For a GET or HEAD request, this is an 5985 indication that the effective request URI identifies a resource that 5986 is subject to content negotiation and the selected representation for 5987 this response can also be found at the identified URI. For other 5988 methods, such a Content-Location indicates that this representation 5989 contains a report on the action's status and the same report is 5990 available (for future access with GET) at the given URI. For 5991 example, a purchase transaction made via a POST request might 5992 include a receipt document as the payload of the 200 response; 5993 the Content-Location value provides an identifier for retrieving 5994 a copy of that same receipt in the future. 5995 </t> 5996 <t> 5997 If Content-Location is included in a request message, then it &MAY; 5998 be interpreted by the origin server as an indication of where the 5999 user agent originally obtained the content of the enclosed 6000 representation (prior to any subsequent modification of the content 6001 by that user agent). In other words, the user agent is providing 6002 the same representation metadata that it received with the original 6003 representation. However, such interpretation &MUST-NOT; be used to 6004 alter the semantics of the method requested by the client. For 6005 example, if a client makes a PUT request on a negotiated resource 6006 and the origin server accepts that PUT (without redirection), then the 6007 new set of values for that resource is expected to be consistent with 6008 the one representation supplied in that PUT; the Content-Location 6009 cannot be used as a form of reverse content selection that 6010 identifies only one of the negotiated representations to be updated. 6011 If the user agent had wanted the latter semantics, it would have applied 6012 the PUT directly to the Content-Location URI. 6013 </t> 6014 <t> 6015 A Content-Location field received in a request message is transitory 6016 information that &SHOULD-NOT; be saved with other representation 6017 metadata for use in later responses. The Content-Location's value 6018 might be saved for use in other contexts, such as within source links 6019 or other metadata. 6020 </t> 6021 <t> 6022 A cache cannot assume that a representation with a Content-Location 6023 different from the URI used to retrieve it can be used to respond to 6024 later requests on that Content-Location URI. 6025 </t> 6026 <t> 6027 If the Content-Location value is a partial URI, the partial URI is 6028 interpreted relative to the effective request URI. 6029 </t> 6030 </section> 6031 6032 <section title="Content-Type" anchor="header.content-type"> 6033 <iref primary="true" item="Content-Type header field" x:for-anchor=""/> 6034 <iref primary="true" item="Header Fields" subitem="Content-Type" x:for-anchor=""/> 6035 <x:anchor-alias value="Content-Type"/> 6036 <t> 6037 The "Content-Type" header field indicates the media type of the 6038 representation. In the case of responses to the HEAD method, the media type is 6039 that which would have been sent had the request been a GET. 6040 </t> 6041 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Type"/> 6042 <x:ref>Content-Type</x:ref> = <x:ref>media-type</x:ref> 6043 </artwork></figure> 6044 <t> 6045 Media types are defined in <xref target="media.types"/>. An example of the field is 6046 </t> 6047 <figure><artwork type="example"> 6048 Content-Type: text/html; charset=ISO-8859-4 6049 </artwork></figure> 6050 <t> 6051 Further discussion of Content-Type is provided in <xref target="representation.data"/>. 6052 </t> 6053 </section> 6054 6055 </section> 6056 6057 <section title="IANA Considerations" anchor="IANA.considerations3"> 6058 6059 <section title="Content Coding Registry" anchor="content.coding.registration"> 6060 <t> 6061 The registration procedure for HTTP Content Codings is now defined 6062 by <xref target="content.coding.registry"/> of this document. 6063 </t> 6064 <t> 6065 The HTTP Content Codings Registry located at <eref target="http://www.iana.org/assignments/http-parameters"/> 6066 shall be updated with the registration below: 6067 </t> 6068 <texttable align="left" suppress-title="true" anchor="iana.content.coding.registration.table"> 6069 <ttcol>Name</ttcol> 6070 <ttcol>Description</ttcol> 6071 <ttcol>Reference</ttcol> 6072 <c>compress</c> 6073 <c>UNIX "compress" program method</c> 6074 <c> 6075 &compress-coding; 6076 </c> 6077 <c>deflate</c> 6078 <c>"deflate" compression mechanism (<xref target="RFC1951"/>) used inside 6079 the "zlib" data format (<xref target="RFC1950"/>) 6080 </c> 6081 <c> 6082 &deflate-coding; 6083 </c> 6084 <c>gzip</c> 6085 <c>Same as GNU zip <xref target="RFC1952"/></c> 6086 <c> 6087 &gzip-coding; 6088 </c> 6089 <c>identity</c> 6090 <c>reserved (synonym for "no encoding" in Accept-Encoding header field)</c> 6091 <c> 6092 <xref target="header.accept-encoding"/> 6093 </c> 6094 </texttable> 6095 </section> 6096 6097 </section> 6098 6099 <section title="Security Considerations" anchor="security.considerations3"> 6100 <t> 6101 This section is meant to inform application developers, information 6102 providers, and users of the security limitations in HTTP/1.1 as 6103 described by this document. The discussion does not include 6104 definitive solutions to the problems revealed, though it does make 6105 some suggestions for reducing security risks. 6106 </t> 6107 6108 <section title="Privacy Issues Connected to Accept Header Fields" anchor="privacy.issues.connected.to.accept.header.fields"> 6109 <t> 6110 Accept header fields can reveal information about the user to all 6111 servers which are accessed. The Accept-Language header field in particular 6112 can reveal information the user would consider to be of a private 6113 nature, because the understanding of particular languages is often 6114 strongly correlated to the membership of a particular ethnic group. 6115 User agents which offer the option to configure the contents of an 6116 Accept-Language header field to be sent in every request are strongly 6117 encouraged to let the configuration process include a message which 6118 makes the user aware of the loss of privacy involved. 6119 </t> 6120 <t> 6121 An approach that limits the loss of privacy would be for a user agent 6122 to omit the sending of Accept-Language header fields by default, and to ask 6123 the user whether or not to start sending Accept-Language header fields to a 6124 server if it detects, by looking for any Vary header fields 6125 generated by the server, that such sending could improve the quality 6126 of service. 6127 </t> 6128 <t> 6129 Elaborate user-customized accept header fields sent in every request, 6130 in particular if these include quality values, can be used by servers 6131 as relatively reliable and long-lived user identifiers. Such user 6132 identifiers would allow content providers to do click-trail tracking, 6133 and would allow collaborating content providers to match cross-server 6134 click-trails or form submissions of individual users. Note that for 6135 many users not behind a proxy, the network address of the host 6136 running the user agent will also serve as a long-lived user 6137 identifier. In environments where proxies are used to enhance 6138 privacy, user agents ought to be conservative in offering accept 6139 header configuration options to end users. As an extreme privacy 6140 measure, proxies could filter the accept header fields in relayed requests. 6141 General purpose user agents which provide a high degree of header 6142 configurability &SHOULD; warn users about the loss of privacy which can 6143 be involved. 6144 </t> 6145 </section> 6146 6147 </section> 6148 6149 6150 <section title="Differences between HTTP and MIME" anchor="differences.between.http.and.mime"> 6151 <t> 6152 HTTP/1.1 uses many of the constructs defined for Internet Mail (<xref target="RFC5322"/>) and the Multipurpose Internet Mail Extensions (MIME <xref target="RFC2045"/>) to 6153 allow a message body to be transmitted in an open variety of 6154 representations and with extensible mechanisms. However, RFC 2045 6155 discusses mail, and HTTP has a few features that are different from 6156 those described in MIME. These differences were carefully chosen 6157 to optimize performance over binary connections, to allow greater 6158 freedom in the use of new media types, to make date comparisons 6159 easier, and to acknowledge the practice of some early HTTP servers 6160 and clients. 6161 </t> 6162 <t> 6163 This appendix describes specific areas where HTTP differs from MIME. 6164 Proxies and gateways to strict MIME environments &SHOULD; be 6165 aware of these differences and provide the appropriate conversions 6166 where necessary. Proxies and gateways from MIME environments to HTTP 6167 also need to be aware of the differences because some conversions 6168 might be required. 6169 </t> 6170 6171 <section title="MIME-Version" anchor="mime-version"> 6172 <iref primary="true" item="MIME-Version header field" x:for-anchor=""/> 6173 <iref primary="true" item="Header Fields" subitem="MIME-Version" x:for-anchor=""/> 6174 <x:anchor-alias value="MIME-Version"/> 6175 <t> 6176 HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages &MAY; 6177 include a single MIME-Version header field to indicate what 6178 version of the MIME protocol was used to construct the message. Use 6179 of the MIME-Version header field indicates that the message is in 6180 full conformance with the MIME protocol (as defined in <xref target="RFC2045"/>). 6181 Proxies/gateways are responsible for ensuring full conformance (where 6182 possible) when exporting HTTP messages to strict MIME environments. 6183 </t> 6184 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="MIME-Version"/> 6185 <x:ref>MIME-Version</x:ref> = 1*<x:ref>DIGIT</x:ref> "." 1*<x:ref>DIGIT</x:ref> 6186 </artwork></figure> 6187 <t> 6188 MIME version "1.0" is the default for use in HTTP/1.1. However, 6189 HTTP/1.1 message parsing and semantics are defined by this document 6190 and not the MIME specification. 6191 </t> 6192 </section> 6193 6194 <section title="Conversion to Canonical Form" anchor="conversion.to.canonical.form"> 6195 <t> 6196 MIME requires that an Internet mail body-part be converted to 6197 canonical form prior to being transferred, as described in <xref target="RFC2049" x:fmt="of" x:sec="4"/>. 6198 <xref target="canonicalization.and.text.defaults"/> of this document describes the forms 6199 allowed for subtypes of the "text" media type when transmitted over 6200 HTTP. <xref target="RFC2046"/> requires that content with a type of "text" represent 6201 line breaks as CRLF and forbids the use of CR or LF outside of line 6202 break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a 6203 line break within text content when a message is transmitted over 6204 HTTP. 6205 </t> 6206 <t> 6207 Where it is possible, a proxy or gateway from HTTP to a strict MIME 6208 environment &SHOULD; translate all line breaks within the text media 6209 types described in <xref target="canonicalization.and.text.defaults"/> 6210 of this document to the RFC 2049 6211 canonical form of CRLF. Note, however, that this might be complicated 6212 by the presence of a Content-Encoding and by the fact that HTTP 6213 allows the use of some character encodings which do not use octets 13 and 6214 10 to represent CR and LF, respectively, as is the case for some multi-byte 6215 character encodings. 6216 </t> 6217 <t> 6218 Conversion will break any cryptographic 6219 checksums applied to the original content unless the original content 6220 is already in canonical form. Therefore, the canonical form is 6221 recommended for any content that uses such checksums in HTTP. 6222 </t> 6223 </section> 6224 6225 6226 <section title="Conversion of Date Formats" anchor="conversion.of.date.formats"> 6227 <t> 6228 HTTP/1.1 uses a restricted set of date formats (&http-date;) to 6229 simplify the process of date comparison. Proxies and gateways from 6230 other protocols &SHOULD; ensure that any Date header field present in a 6231 message conforms to one of the HTTP/1.1 formats and rewrite the date 6232 if necessary. 6233 </t> 6234 </section> 6235 6236 <section title="Introduction of Content-Encoding" anchor="introduction.of.content-encoding"> 6237 <t> 6238 MIME does not include any concept equivalent to HTTP/1.1's 6239 Content-Encoding header field. Since this acts as a modifier on the 6240 media type, proxies and gateways from HTTP to MIME-compliant 6241 protocols &MUST; either change the value of the Content-Type header 6242 field or decode the representation before forwarding the message. (Some 6243 experimental applications of Content-Type for Internet mail have used 6244 a media-type parameter of ";conversions=<content-coding>" to perform 6245 a function equivalent to Content-Encoding. However, this parameter is 6246 not part of the MIME standards). 6247 </t> 6248 </section> 6249 6250 <section title="No Content-Transfer-Encoding" anchor="no.content-transfer-encoding"> 6251 <iref item="Content-Transfer-Encoding header field" x:for-anchor=""/> 6252 <iref item="Header Fields" subitem="Content-Transfer-Encoding" x:for-anchor=""/> 6253 <t> 6254 HTTP does not use the Content-Transfer-Encoding field of MIME. 6255 Proxies and gateways from MIME-compliant protocols to HTTP &MUST; 6256 remove any Content-Transfer-Encoding 6257 prior to delivering the response message to an HTTP client. 6258 </t> 6259 <t> 6260 Proxies and gateways from HTTP to MIME-compliant protocols are 6261 responsible for ensuring that the message is in the correct format 6262 and encoding for safe transport on that protocol, where "safe 6263 transport" is defined by the limitations of the protocol being used. 6264 Such a proxy or gateway &SHOULD; label the data with an appropriate 6265 Content-Transfer-Encoding if doing so will improve the likelihood of 6266 safe transport over the destination protocol. 6267 </t> 6268 </section> 6269 6270 <section title="Introduction of Transfer-Encoding" anchor="introduction.of.transfer-encoding"> 6271 <t> 6272 HTTP/1.1 introduces the Transfer-Encoding header field (&header-transfer-encoding;). 6273 Proxies/gateways &MUST; remove any transfer-coding prior to 6274 forwarding a message via a MIME-compliant protocol. 6275 </t> 6276 </section> 6277 6278 <section title="MHTML and Line Length Limitations" anchor="mhtml.line.length"> 6279 <t> 6280 HTTP implementations which share code with MHTML <xref target="RFC2557"/> implementations 6281 need to be aware of MIME line length limitations. Since HTTP does not 6282 have this limitation, HTTP does not fold long lines. MHTML messages 6283 being transported by HTTP follow all conventions of MHTML, including 6284 line length limitations and folding, canonicalization, etc., since 6285 HTTP transports all message-bodies as payload (see <xref target="multipart.types"/>) and 6286 does not interpret the content or any MIME header lines that might be 6287 contained therein. 6288 </t> 6289 </section> 6290 </section> 6291 6292 <section title="Additional Features" anchor="additional.features"> 6293 <t> 6294 <xref target="RFC1945"/> and <xref target="RFC2068"/> document protocol elements used by some 6295 existing HTTP implementations, but not consistently and correctly 6296 across most HTTP/1.1 applications. Implementors are advised to be 6297 aware of these features, but cannot rely upon their presence in, or 6298 interoperability with, other HTTP/1.1 applications. Some of these 6299 describe proposed experimental features, and some describe features 6300 that experimental deployment found lacking that are now addressed in 6301 the base HTTP/1.1 specification. 6302 </t> 6303 <t> 6304 A number of other header fields, such as Content-Disposition and Title, 6305 from SMTP and MIME are also often implemented (see <xref target="RFC6266"/> 6306 and <xref target="RFC2076"/>). 6307 </t> 6308 </section> 6309 6310 <section title="Changes from RFC 2616" anchor="changes.from.rfc.2616-3"> 6311 <t> 6312 Clarify contexts that charset is used in. 6313 (<xref target="character.sets"/>) 6314 </t> 6315 <t> 6316 Registration of Content Codings now requires IETF Review 6317 (<xref target="content.coding.registry"/>) 6318 </t> 6319 <t> 6320 Remove the default character encoding for text media types; the default 6321 now is whatever the media type definition says. 6322 (<xref target="canonicalization.and.text.defaults"/>) 6323 </t> 6324 <t> 6325 Change ABNF productions for header fields to only define the field value. 6326 (<xref target="header.field.definitions"/>) 6327 </t> 6328 <t> 6329 Remove definition of Content-MD5 header field because it was inconsistently 6330 implemented with respect to partial responses, and also because of known 6331 deficiencies in the hash algorithm itself (see <xref target="RFC6151"/> for details). 6332 (<xref target="header.field.definitions"/>) 6333 </t> 6334 <t> 6335 Remove ISO-8859-1 special-casing in Accept-Charset. 6336 (<xref target="header.accept-charset"/>) 6337 </t> 6338 <t> 6339 Remove base URI setting semantics for Content-Location due to poor 6340 implementation support, which was caused by too many broken servers emitting 6341 bogus Content-Location header fields, and also the potentially undesirable effect 6342 of potentially breaking relative links in content-negotiated resources. 6343 (<xref target="header.content-location"/>) 6344 </t> 6345 <t> 6346 Remove reference to non-existant identity transfer-coding value tokens. 6347 (<xref target="no.content-transfer-encoding"/>) 6348 </t> 6349 <t> 6350 Remove discussion of Content-Disposition header field, it is now defined 6351 by <xref target="RFC6266"/>. 6352 (<xref target="additional.features"/>) 6353 </t> 6354 </section> 6355 6356 <section title="Change Log (to be removed by RFC Editor before publication)" anchor="change.log3"> 6357 6358 <section title="Since RFC 2616"> 6359 <t> 6360 Extracted relevant partitions from <xref target="RFC2616"/>. 6361 </t> 6362 </section> 6363 6364 <section title="Since draft-ietf-httpbis-p3-payload-00"> 6365 <t> 6366 Closed issues: 6367 <list style="symbols"> 6368 <t> 6369 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/8"/>: 6370 "Media Type Registrations" 6371 (<eref target="http://purl.org/NET/http-errata#media-reg"/>) 6372 </t> 6373 <t> 6374 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/14"/>: 6375 "Clarification regarding quoting of charset values" 6376 (<eref target="http://purl.org/NET/http-errata#charactersets"/>) 6377 </t> 6378 <t> 6379 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/16"/>: 6380 "Remove 'identity' token references" 6381 (<eref target="http://purl.org/NET/http-errata#identity"/>) 6382 </t> 6383 <t> 6384 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/25"/>: 6385 "Accept-Encoding BNF" 6386 </t> 6387 <t> 6388 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/35"/>: 6389 "Normative and Informative references" 6390 </t> 6391 <t> 6392 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/46"/>: 6393 "RFC1700 references" 6394 </t> 6395 <t> 6396 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/55"/>: 6397 "Updating to RFC4288" 6398 </t> 6399 <t> 6400 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/65"/>: 6401 "Informative references" 6402 </t> 6403 <t> 6404 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/66"/>: 6405 "ISO-8859-1 Reference" 6406 </t> 6407 <t> 6408 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>: 6409 "Encoding References Normative" 6410 </t> 6411 <t> 6412 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/86"/>: 6413 "Normative up-to-date references" 6414 </t> 6415 </list> 6416 </t> 6417 </section> 6418 6419 <section title="Since draft-ietf-httpbis-p3-payload-01"> 6420 <t> 6421 Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>): 6422 <list style="symbols"> 6423 <t> 6424 Add explicit references to BNF syntax and rules imported from other parts of the specification. 6425 </t> 6426 </list> 6427 </t> 6428 </section> 6429 6430 <section title="Since draft-ietf-httpbis-p3-payload-02" anchor="changes.3.since.02"> 6431 <t> 6432 Closed issues: 6433 <list style="symbols"> 6434 <t> 6435 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>: 6436 "Quoting Charsets" 6437 </t> 6438 <t> 6439 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/105"/>: 6440 "Classification for Allow header" 6441 </t> 6442 <t> 6443 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/115"/>: 6444 "missing default for qvalue in description of Accept-Encoding" 6445 </t> 6446 </list> 6447 </t> 6448 <t> 6449 Ongoing work on IANA Message Header Field Registration (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/40"/>): 6450 <list style="symbols"> 6451 <t> 6452 Reference RFC 3984, and update header field registrations for headers defined 6453 in this document. 6454 </t> 6455 </list> 6456 </t> 6457 </section> 6458 6459 <section title="Since draft-ietf-httpbis-p3-payload-03" anchor="changes.3.since.03"> 6460 <t> 6461 Closed issues: 6462 <list style="symbols"> 6463 <t> 6464 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/67"/>: 6465 "Quoting Charsets" 6466 </t> 6467 <t> 6468 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/113"/>: 6469 "language tag matching (Accept-Language) vs RFC4647" 6470 </t> 6471 <t> 6472 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/121"/>: 6473 "RFC 1806 has been replaced by RFC2183" 6474 </t> 6475 </list> 6476 </t> 6477 <t> 6478 Other changes: 6479 <list style="symbols"> 6480 <t> 6481 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/68"/>: 6482 "Encoding References Normative" — rephrase the annotation and reference 6483 BCP97. 6484 </t> 6485 </list> 6486 </t> 6487 </section> 6488 6489 <section title="Since draft-ietf-httpbis-p3-payload-04" anchor="changes.3.since.04"> 6490 <t> 6491 Closed issues: 6492 <list style="symbols"> 6493 <t> 6494 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/132"/>: 6495 "RFC 2822 is updated by RFC 5322" 6496 </t> 6497 </list> 6498 </t> 6499 <t> 6500 Ongoing work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>): 6501 <list style="symbols"> 6502 <t> 6503 Use "/" instead of "|" for alternatives. 6504 </t> 6505 <t> 6506 Introduce new ABNF rules for "bad" whitespace ("BWS"), optional 6507 whitespace ("OWS") and required whitespace ("RWS"). 6508 </t> 6509 <t> 6510 Rewrite ABNFs to spell out whitespace rules, factor out 6511 header field value format definitions. 6512 </t> 6513 </list> 6514 </t> 6515 </section> 6516 6517 <section title="Since draft-ietf-httpbis-p3-payload-05" anchor="changes.3.since.05"> 6518 <t> 6519 Closed issues: 6520 <list style="symbols"> 6521 <t> 6522 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/118"/>: 6523 "Join "Differences Between HTTP Entities and RFC 2045 Entities"?" 6524 </t> 6525 </list> 6526 </t> 6527 <t> 6528 Final work on ABNF conversion (<eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/36"/>): 6529 <list style="symbols"> 6530 <t> 6531 Add appendix containing collected and expanded ABNF, reorganize ABNF introduction. 6532 </t> 6533 </list> 6534 </t> 6535 <t> 6536 Other changes: 6537 <list style="symbols"> 6538 <t> 6539 Move definition of quality values into Part 1. 6540 </t> 6541 </list> 6542 </t> 6543 </section> 6544 6545 <section title="Since draft-ietf-httpbis-p3-payload-06" anchor="changes.3.since.06"> 6546 <t> 6547 Closed issues: 6548 <list style="symbols"> 6549 <t> 6550 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>: 6551 "Content-Location isn't special" 6552 </t> 6553 <t> 6554 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>: 6555 "Content Sniffing" 6556 </t> 6557 </list> 6558 </t> 6559 </section> 6560 6561 <section title="Since draft-ietf-httpbis-p3-payload-07" anchor="changes.3.since.07"> 6562 <t> 6563 Closed issues: 6564 <list style="symbols"> 6565 <t> 6566 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/13"/>: 6567 "Updated reference for language tags" 6568 </t> 6569 <t> 6570 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/110"/>: 6571 "Clarify rules for determining what entities a response carries" 6572 </t> 6573 <t> 6574 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/154"/>: 6575 "Content-Location base-setting problems" 6576 </t> 6577 <t> 6578 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>: 6579 "Content Sniffing" 6580 </t> 6581 <t> 6582 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/188"/>: 6583 "pick IANA policy (RFC5226) for Transfer Coding / Content Coding" 6584 </t> 6585 <t> 6586 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/189"/>: 6587 "move definitions of gzip/deflate/compress to part 1" 6588 </t> 6589 </list> 6590 </t> 6591 <t> 6592 Partly resolved issues: 6593 <list style="symbols"> 6594 <t> 6595 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/148"/>: 6596 "update IANA requirements wrt Transfer-Coding values" (add the 6597 IANA Considerations subsection) 6598 </t> 6599 <t> 6600 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/149"/>: 6601 "update IANA requirements wrt Content-Coding values" (add the 6602 IANA Considerations subsection) 6603 </t> 6604 </list> 6605 </t> 6606 </section> 6607 6608 <section title="Since draft-ietf-httpbis-p3-payload-08" anchor="changes.3.since.08"> 6609 <t> 6610 Closed issues: 6611 <list style="symbols"> 6612 <t> 6613 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/81"/>: 6614 "Content Negotiation for media types" 6615 </t> 6616 <t> 6617 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/181"/>: 6618 "Accept-Language: which RFC4647 filtering?" 6619 </t> 6620 </list> 6621 </t> 6622 </section> 6623 6624 <section title="Since draft-ietf-httpbis-p3-payload-09" anchor="changes.3.since.09"> 6625 <t> 6626 Closed issues: 6627 <list style="symbols"> 6628 <t> 6629 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/122"/>: 6630 "MIME-Version not listed in P1, general header fields" 6631 </t> 6632 <t> 6633 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/143"/>: 6634 "IANA registry for content/transfer encodings" 6635 </t> 6636 <t> 6637 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/155"/>: 6638 "Content Sniffing" 6639 </t> 6640 <t> 6641 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/200"/>: 6642 "use of term "word" when talking about header structure" 6643 </t> 6644 </list> 6645 </t> 6646 <t> 6647 Partly resolved issues: 6648 <list style="symbols"> 6649 <t> 6650 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/196"/>: 6651 "Term for the requested resource's URI" 6652 </t> 6653 </list> 6654 </t> 6655 </section> 6656 6657 <section title="Since draft-ietf-httpbis-p3-payload-10" anchor="changes.3.since.10"> 6658 <t> 6659 Closed issues: 6660 <list style="symbols"> 6661 <t> 6662 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/69"/>: 6663 "Clarify 'Requested Variant'" 6664 </t> 6665 <t> 6666 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/80"/>: 6667 "Content-Location isn't special" 6668 </t> 6669 <t> 6670 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/90"/>: 6671 "Delimiting messages with multipart/byteranges" 6672 </t> 6673 <t> 6674 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/109"/>: 6675 "Clarify entity / representation / variant terminology" 6676 </t> 6677 <t> 6678 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/136"/>: 6679 "confusing req. language for Content-Location" 6680 </t> 6681 <t> 6682 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/167"/>: 6683 "Content-Location on 304 responses" 6684 </t> 6685 <t> 6686 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/183"/>: 6687 "'requested resource' in content-encoding definition" 6688 </t> 6689 <t> 6690 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/220"/>: 6691 "consider removing the 'changes from 2068' sections" 6692 </t> 6693 </list> 6694 </t> 6695 <t> 6696 Partly resolved issues: 6697 <list style="symbols"> 6698 <t> 6699 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>: 6700 "Content-MD5 and partial responses" 6701 </t> 6702 </list> 6703 </t> 6704 </section> 6705 6706 <section title="Since draft-ietf-httpbis-p3-payload-11" anchor="changes.3.since.11"> 6707 <t> 6708 Closed issues: 6709 <list style="symbols"> 6710 <t> 6711 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/123"/>: 6712 "Factor out Content-Disposition" 6713 </t> 6714 </list> 6715 </t> 6716 </section> 6717 6718 <section title="Since draft-ietf-httpbis-p3-payload-12" anchor="changes.3.since.12"> 6719 <t> 6720 Closed issues: 6721 <list style="symbols"> 6722 <t> 6723 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/224"/>: 6724 "Header Classification" 6725 </t> 6726 <t> 6727 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>: 6728 "untangle ABNFs for header fields" 6729 </t> 6730 <t> 6731 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/277"/>: 6732 "potentially misleading MAY in media-type def" 6733 </t> 6734 </list> 6735 </t> 6736 </section> 6737 6738 <section title="Since draft-ietf-httpbis-p3-payload-13" anchor="changes.3.since.13"> 6739 <t> 6740 Closed issues: 6741 <list style="symbols"> 6742 <t> 6743 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/20"/>: 6744 "Default charsets for text media types" 6745 </t> 6746 <t> 6747 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/178"/>: 6748 "Content-MD5 and partial responses" 6749 </t> 6750 <t> 6751 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/276"/>: 6752 "untangle ABNFs for header fields" 6753 </t> 6754 <t> 6755 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/281"/>: 6756 "confusing undefined parameter in media range example" 6757 </t> 6758 </list> 6759 </t> 6760 </section> 6761 6762 <section title="Since draft-ietf-httpbis-p3-payload-14" anchor="changes.3.since.14"> 6763 <t> 6764 None. 6765 </t> 6766 </section> 6767 6768 <section title="Since draft-ietf-httpbis-p3-payload-15" anchor="changes.3.since.15"> 6769 <t> 6770 Closed issues: 6771 <list style="symbols"> 6772 <t> 6773 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/285"/>: 6774 "Strength of requirements on Accept re: 406" 6775 </t> 6776 </list> 6777 </t> 6778 </section> 6779 6780 <section title="Since draft-ietf-httpbis-p3-payload-16" anchor="changes.3.since.16"> 6781 <t> 6782 Closed issues: 6783 <list style="symbols"> 6784 <t> 6785 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/186"/>: 6786 "Document HTTP's error-handling philosophy" 6787 </t> 6788 </list> 6789 </t> 6790 </section> 6791 6792 <section title="Since draft-ietf-httpbis-p3-payload-17" anchor="changes.3.since.17"> 6793 <t> 6794 Closed issues: 6795 <list style="symbols"> 6796 <t> 6797 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/323"/>: 6798 "intended maturity level vs normative references" 6799 </t> 6800 </list> 6801 </t> 6802 </section> 6803 6804 <section title="Since draft-ietf-httpbis-p3-payload-18" anchor="changes.3.since.18"> 6805 <t> 6806 Closed issues: 6807 <list style="symbols"> 6808 <t> 6809 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/330"/>: 6810 "is ETag a representation header field?" 6811 </t> 6812 <t> 6813 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/338"/>: 6814 "Content-Location doesn't constrain the cardinality of representations" 6815 </t> 6816 <t> 6817 <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/346"/>: 6818 "make IANA policy definitions consistent" 6819 </t> 6820 </list> 6821 </t> 6822 </section> 6823 6824 <section title="Since draft-ietf-httpbis-p3-payload-19" anchor="changes.3.since.19"> 6825 <t> 6826 None yet. 6827 </t> 6828 </section> 6829 6830 </section> 6831 </section> 6832 4846 6833 </back> 4847 6834 </rfc> -
draft-ietf-httpbis/latest/p3-payload.html
r1642 r1643 112 112 font-style: normal; 113 113 } 114 div.note {115 margin-left: 2em;116 }117 114 dd { 118 115 margin-right: 2em; … … 211 208 margin-left: 2em; 212 209 } 213 table.tt {214 vertical-align: top;215 }216 table.full {217 border-style: outset;218 border-width: 1px;219 }220 table.headers {221 border-style: outset;222 border-width: 1px;223 }224 table.tt td {225 vertical-align: top;226 }227 table.full td {228 border-style: inset;229 border-width: 1px;230 }231 table.tt th {232 vertical-align: top;233 }234 table.full th {235 border-style: inset;236 border-width: 1px;237 }238 table.headers th {239 border-style: none none inset none;240 border-width: 1px;241 }242 table.left {243 margin-right: auto;244 }245 table.right {246 margin-left: auto;247 }248 table.center {249 margin-left: auto;250 margin-right: auto;251 }252 caption {253 caption-side: bottom;254 font-weight: bold;255 font-size: 9pt;256 margin-top: .5em;257 }258 259 210 table.header { 260 211 border-spacing: 1px; … … 273 224 background-color: gray; 274 225 width: 50%; 275 }276 table.header a {277 color: white;278 226 } 279 227 td.reference { … … 311 259 margin-left: 0em; 312 260 } 313 ul.ind, ul.ind ul { 314 list-style: none; 315 margin-left: 1.5em; 316 margin-right: 0em; 317 padding-left: 0em; 318 page-break-before: avoid; 319 } 320 ul.ind li { 321 font-weight: bold; 322 line-height: 200%; 323 margin-left: 0em; 324 margin-right: 0em; 325 } 326 ul.ind li li { 327 font-weight: normal; 328 line-height: 150%; 329 margin-left: 0em; 330 margin-right: 0em; 331 } 332 .avoidbreak { 333 page-break-inside: avoid; 334 } 335 .bcp14 { 336 font-style: normal; 337 text-transform: lowercase; 338 font-variant: small-caps; 339 } 261 340 262 .comment { 341 263 background-color: yellow; … … 481 403 <link rel="Author" href="#rfc.authors"> 482 404 <link rel="Copyright" href="#rfc.copyrightnotice"> 483 <link rel="Index" href="#rfc.index">484 405 <link rel="Chapter" title="1 Introduction" href="#rfc.section.1"> 485 <link rel="Chapter" title="2 Protocol Parameters" href="#rfc.section.2">486 <link rel="Chapter" title="3 Payload" href="#rfc.section.3">487 <link rel="Chapter" title="4 Representation" href="#rfc.section.4">488 <link rel="Chapter" title="5 Content Negotiation" href="#rfc.section.5">489 <link rel="Chapter" title="6 Header Field Definitions" href="#rfc.section.6">490 <link rel="Chapter" title="7 IANA Considerations" href="#rfc.section.7">491 <link rel="Chapter" title="8 Security Considerations" href="#rfc.section.8">492 <link rel="Chapter" href="#rfc.section.9" title="9 References">493 <link rel="Appendix" title="A Differences between HTTP and MIME" href="#rfc.section.A">494 <link rel="Appendix" title="B Additional Features" href="#rfc.section.B">495 <link rel="Appendix" title="C Changes from RFC 2616" href="#rfc.section.C">496 <link rel="Appendix" title="D Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.D">497 <link href="p2-semantics.html" rel="prev">498 <link href="p4-conditional.html" rel="next">499 406 <meta name="generator" content="http://greenbytes.de/tech/webdav/rfc2629.xslt, Revision 1.570, 2012-02-13 19:17:35, XSLT vendor: SAXON 8.9 from Saxonica http://www.saxonica.com/"> 500 407 <link rel="schema.dct" href="http://purl.org/dc/terms/"> … … 504 411 <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p3-payload-latest"> 505 412 <meta name="dct.issued" scheme="ISO8601" content="2012-03-30"> 506 <meta name="dct.replaces" content="urn:ietf:rfc:2616">507 413 <meta name="dct.abstract" content="This part is now obsolete. Please see HTTPbis, Part 2."> 508 414 <meta name="description" content="This part is now obsolete. Please see HTTPbis, Part 2."> … … 520 426 </tr> 521 427 <tr> 522 <td class="left">Obsoletes: <a href="http://tools.ietf.org/html/rfc2616">2616</a> (if approved) 523 </td> 428 <td class="left">Intended status: Standards Track</td> 524 429 <td class="right">Y. Lafon, Editor</td> 525 430 </tr> 526 431 <tr> 527 <td class="left"> Intended status: Standards Track</td>432 <td class="left">Expires: October 1, 2012</td> 528 433 <td class="right">W3C</td> 529 434 </tr> 530 435 <tr> 531 <td class="left"> Expires: October 1, 2012</td>436 <td class="left"></td> 532 437 <td class="right">J. Reschke, Editor</td> 533 438 </tr> … … 572 477 <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1> 573 478 <ul class="toc"> 574 <li>1. <a href="#introduction">Introduction</a><ul> 575 <li>1.1 <a href="#notation">Syntax Notation</a><ul> 576 <li>1.1.1 <a href="#core.rules">Core Rules</a></li> 577 <li>1.1.2 <a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li> 578 </ul> 579 </li> 580 </ul> 581 </li> 582 <li>2. <a href="#protocol.parameters">Protocol Parameters</a><ul> 583 <li>2.1 <a href="#character.sets">Character Encodings (charset)</a></li> 584 <li>2.2 <a href="#content.codings">Content Codings</a><ul> 585 <li>2.2.1 <a href="#content.coding.registry">Content Coding Registry</a></li> 586 </ul> 587 </li> 588 <li>2.3 <a href="#media.types">Media Types</a><ul> 589 <li>2.3.1 <a href="#canonicalization.and.text.defaults">Canonicalization and Text Defaults</a></li> 590 <li>2.3.2 <a href="#multipart.types">Multipart Types</a></li> 591 </ul> 592 </li> 593 <li>2.4 <a href="#language.tags">Language Tags</a></li> 594 </ul> 595 </li> 596 <li>3. <a href="#payload">Payload</a><ul> 597 <li>3.1 <a href="#payload.header.fields">Payload Header Fields</a></li> 598 <li>3.2 <a href="#payload.body">Payload Body</a></li> 599 </ul> 600 </li> 601 <li>4. <a href="#representation">Representation</a><ul> 602 <li>4.1 <a href="#representation.header.fields">Representation Header Fields</a></li> 603 <li>4.2 <a href="#representation.data">Representation Data</a></li> 604 </ul> 605 </li> 606 <li>5. <a href="#content.negotiation">Content Negotiation</a><ul> 607 <li>5.1 <a href="#server-driven.negotiation">Server-driven Negotiation</a></li> 608 <li>5.2 <a href="#agent-driven.negotiation">Agent-driven Negotiation</a></li> 609 </ul> 610 </li> 611 <li>6. <a href="#header.field.definitions">Header Field Definitions</a><ul> 612 <li>6.1 <a href="#header.accept">Accept</a></li> 613 <li>6.2 <a href="#header.accept-charset">Accept-Charset</a></li> 614 <li>6.3 <a href="#header.accept-encoding">Accept-Encoding</a></li> 615 <li>6.4 <a href="#header.accept-language">Accept-Language</a></li> 616 <li>6.5 <a href="#header.content-encoding">Content-Encoding</a></li> 617 <li>6.6 <a href="#header.content-language">Content-Language</a></li> 618 <li>6.7 <a href="#header.content-location">Content-Location</a></li> 619 <li>6.8 <a href="#header.content-type">Content-Type</a></li> 620 </ul> 621 </li> 622 <li>7. <a href="#IANA.considerations">IANA Considerations</a><ul> 623 <li>7.1 <a href="#content.coding.registration">Content Coding Registry</a></li> 624 </ul> 625 </li> 626 <li>8. <a href="#security.considerations">Security Considerations</a><ul> 627 <li>8.1 <a href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></li> 628 </ul> 629 </li> 630 <li>9. <a href="#rfc.references">References</a><ul> 631 <li>9.1 <a href="#rfc.references.1">Normative References</a></li> 632 <li>9.2 <a href="#rfc.references.2">Informative References</a></li> 633 </ul> 634 </li> 479 <li>1. <a href="#introduction">Introduction</a></li> 635 480 <li><a href="#rfc.authors">Authors' Addresses</a></li> 636 <li>A. <a href="#differences.between.http.and.mime">Differences between HTTP and MIME</a><ul>637 <li>A.1 <a href="#mime-version">MIME-Version</a></li>638 <li>A.2 <a href="#conversion.to.canonical.form">Conversion to Canonical Form</a></li>639 <li>A.3 <a href="#conversion.of.date.formats">Conversion of Date Formats</a></li>640 <li>A.4 <a href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></li>641 <li>A.5 <a href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></li>642 <li>A.6 <a href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></li>643 <li>A.7 <a href="#mhtml.line.length">MHTML and Line Length Limitations</a></li>644 </ul>645 </li>646 <li>B. <a href="#additional.features">Additional Features</a></li>647 <li>C. <a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li>648 <li>D. <a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>649 <li>D.1 <a href="#rfc.section.D.1">Since RFC 2616</a></li>650 <li>D.2 <a href="#rfc.section.D.2">Since draft-ietf-httpbis-p3-payload-00</a></li>651 <li>D.3 <a href="#rfc.section.D.3">Since draft-ietf-httpbis-p3-payload-01</a></li>652