Changeset 1645 for draft-ietf-httpbis


Ignore:
Timestamp:
30/03/12 15:39:09 (9 years ago)
Author:
julian.reschke@…
Message:

Step 7 of p2/p3-merge (see #351)

Location:
draft-ietf-httpbis/latest
Files:
5 edited

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Unmodified
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Removed

  • draft-ietf-httpbis/latest/p1-messaging.html

    r1643 r1645  
    757757      <p id="rfc.section.1.p.1">The Hypertext Transfer Protocol (HTTP) is an application-level request/response protocol that uses extensible semantics and
    758758         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&nbsp;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).
     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&nbsp;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.6</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).
    760760      </p>
    761761      <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
    … …  
    12231223                 ; see <a href="#field.parsing" title="Field Parsing">Section&nbsp;3.2.2</a>
    12241224</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.Part2.7"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> as containing the origination timestamp for the message in which it appears.
     1225         the Date header field is defined in <a href="p2-semantics.html#header.date" title="Date">Section 7.10</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.
    12261226      </p>
    12271227      <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
    … …  
    14181418      <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&nbsp;3.2</a>, before determining the message body length.
    14191419      </p>
    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.
     1420      <p id="rfc.section.3.3.1.p.7">Unlike Content-Encoding (<a href="p2-semantics.html#content.codings" title="Content Codings">Section 6.4</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.
    14211421      </p>
    14221422      <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
    … …  
    17251725      </p>
    17261726      <h3 id="rfc.section.4.3.1"><a href="#rfc.section.4.3.1">4.3.1</a>&nbsp;<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&nbsp;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
     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&nbsp;4.3</a>) and content negotiation (<a href="p2-semantics.html#content.negotiation" title="Content Negotiation">Appendix D.3</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
    17281728         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
    17291729         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.
    … …  
    21872187      <p id="rfc.section.6.4.3.p.2">Requirements for HTTP/1.1 clients: </p>
    21882188      <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.Part2.19"><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.
     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 7.11</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 7.11</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.
    21922192         </li>
    21932193      </ul>
    … …  
    25342534         <li>Pointer to specification text</li>
    25352535      </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="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&nbsp;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">Section 6.4</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&nbsp;4.2</a>.
    25372537      </p>
    25382538      <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.
    … …  
    37583758                        <li><em>Section 4.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.25">8.6</a></li>
    37593759                        <li><em>Section 4.6.12</em>&nbsp;&nbsp;<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>&nbsp;&nbsp;<a href="#rfc.xref.Part2.7">3.2</a></li>
    3761                         <li><em>Section 7.3</em>&nbsp;&nbsp;<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>&nbsp;&nbsp;<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>&nbsp;&nbsp;<a href="#rfc.xref.Part2.10">4.3.1</a></li>
    3764                         <li><em>Appendix D.8</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.1">1</a></li>
     3760                        <li><em>Section 6.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.9">3.3.1</a>, <a href="#rfc.xref.Part2.23">7.4</a></li>
     3761                        <li><em>Section 7.10</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.7">3.2</a></li>
     3762                        <li><em>Section 7.11</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.19">6.4.3</a>, <a href="#rfc.xref.Part2.20">6.4.3</a></li>
     3763                        <li><em>Appendix D.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.10">4.3.1</a></li>
     3764                        <li><em>Appendix D.6</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.1">1</a></li>
    37653765                     </ul>
    37663766                  </li>

  • draft-ietf-httpbis/latest/p2-semantics.html

    r1644 r1645  
    708708         </li>
    709709         <li>7.&nbsp;&nbsp;&nbsp;<a href="#header.field.definitions">Header Field Definitions</a><ul>
    710                <li>7.1&nbsp;&nbsp;&nbsp;<a href="#header.allow">Allow</a></li>
    711                <li>7.2&nbsp;&nbsp;&nbsp;<a href="#header.date">Date</a></li>
    712                <li>7.3&nbsp;&nbsp;&nbsp;<a href="#header.expect">Expect</a></li>
    713                <li>7.4&nbsp;&nbsp;&nbsp;<a href="#header.from">From</a></li>
    714                <li>7.5&nbsp;&nbsp;&nbsp;<a href="#header.location">Location</a></li>
    715                <li>7.6&nbsp;&nbsp;&nbsp;<a href="#header.max-forwards">Max-Forwards</a></li>
    716                <li>7.7&nbsp;&nbsp;&nbsp;<a href="#header.referer">Referer</a></li>
    717                <li>7.8&nbsp;&nbsp;&nbsp;<a href="#header.retry-after">Retry-After</a></li>
    718                <li>7.9&nbsp;&nbsp;&nbsp;<a href="#header.server">Server</a></li>
    719                <li>7.10&nbsp;&nbsp;&nbsp;<a href="#header.user-agent">User-Agent</a></li>
     710               <li>7.1&nbsp;&nbsp;&nbsp;<a href="#header.accept">Accept</a></li>
     711               <li>7.2&nbsp;&nbsp;&nbsp;<a href="#header.accept-charset">Accept-Charset</a></li>
     712               <li>7.3&nbsp;&nbsp;&nbsp;<a href="#header.accept-encoding">Accept-Encoding</a></li>
     713               <li>7.4&nbsp;&nbsp;&nbsp;<a href="#header.accept-language">Accept-Language</a></li>
     714               <li>7.5&nbsp;&nbsp;&nbsp;<a href="#header.allow">Allow</a></li>
     715               <li>7.6&nbsp;&nbsp;&nbsp;<a href="#header.content-encoding">Content-Encoding</a></li>
     716               <li>7.7&nbsp;&nbsp;&nbsp;<a href="#header.content-language">Content-Language</a></li>
     717               <li>7.8&nbsp;&nbsp;&nbsp;<a href="#header.content-location">Content-Location</a></li>
     718               <li>7.9&nbsp;&nbsp;&nbsp;<a href="#header.content-type">Content-Type</a></li>
     719               <li>7.10&nbsp;&nbsp;&nbsp;<a href="#header.date">Date</a></li>
     720               <li>7.11&nbsp;&nbsp;&nbsp;<a href="#header.expect">Expect</a></li>
     721               <li>7.12&nbsp;&nbsp;&nbsp;<a href="#header.from">From</a></li>
     722               <li>7.13&nbsp;&nbsp;&nbsp;<a href="#header.location">Location</a></li>
     723               <li>7.14&nbsp;&nbsp;&nbsp;<a href="#header.max-forwards">Max-Forwards</a></li>
     724               <li>7.15&nbsp;&nbsp;&nbsp;<a href="#header.referer">Referer</a></li>
     725               <li>7.16&nbsp;&nbsp;&nbsp;<a href="#header.retry-after">Retry-After</a></li>
     726               <li>7.17&nbsp;&nbsp;&nbsp;<a href="#header.server">Server</a></li>
     727               <li>7.18&nbsp;&nbsp;&nbsp;<a href="#header.user-agent">User-Agent</a></li>
    720728            </ul>
    721729         </li>
    … …  
    782790                  </ul>
    783791               </li>
    784                <li>D.4&nbsp;&nbsp;&nbsp;<a href="#header.field.definitions3">Header Field Definitions</a><ul>
    785                      <li>D.4.1&nbsp;&nbsp;&nbsp;<a href="#header.accept">Accept</a></li>
    786                      <li>D.4.2&nbsp;&nbsp;&nbsp;<a href="#header.accept-charset">Accept-Charset</a></li>
    787                      <li>D.4.3&nbsp;&nbsp;&nbsp;<a href="#header.accept-encoding">Accept-Encoding</a></li>
    788                      <li>D.4.4&nbsp;&nbsp;&nbsp;<a href="#header.accept-language">Accept-Language</a></li>
    789                      <li>D.4.5&nbsp;&nbsp;&nbsp;<a href="#header.content-encoding">Content-Encoding</a></li>
    790                      <li>D.4.6&nbsp;&nbsp;&nbsp;<a href="#header.content-language">Content-Language</a></li>
    791                      <li>D.4.7&nbsp;&nbsp;&nbsp;<a href="#header.content-location">Content-Location</a></li>
    792                      <li>D.4.8&nbsp;&nbsp;&nbsp;<a href="#header.content-type">Content-Type</a></li>
     792               <li>D.4&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations3">IANA Considerations</a><ul>
     793                     <li>D.4.1&nbsp;&nbsp;&nbsp;<a href="#content.coding.registration">Content Coding Registry</a></li>
    793794                  </ul>
    794795               </li>
    795                <li>D.5&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations3">IANA Considerations</a><ul>
    796                      <li>D.5.1&nbsp;&nbsp;&nbsp;<a href="#content.coding.registration">Content Coding Registry</a></li>
     796               <li>D.5&nbsp;&nbsp;&nbsp;<a href="#security.considerations3">Security Considerations</a><ul>
     797                     <li>D.5.1&nbsp;&nbsp;&nbsp;<a href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></li>
    797798                  </ul>
    798799               </li>
    799                <li>D.6&nbsp;&nbsp;&nbsp;<a href="#security.considerations3">Security Considerations</a><ul>
    800                      <li>D.6.1&nbsp;&nbsp;&nbsp;<a href="#privacy.issues.connected.to.accept.header.fields">Privacy Issues Connected to Accept Header Fields</a></li>
     800               <li>D.6&nbsp;&nbsp;&nbsp;<a href="#differences.between.http.and.mime">Differences between HTTP and MIME</a><ul>
     801                     <li>D.6.1&nbsp;&nbsp;&nbsp;<a href="#mime-version">MIME-Version</a></li>
     802                     <li>D.6.2&nbsp;&nbsp;&nbsp;<a href="#conversion.to.canonical.form">Conversion to Canonical Form</a></li>
     803                     <li>D.6.3&nbsp;&nbsp;&nbsp;<a href="#conversion.of.date.formats">Conversion of Date Formats</a></li>
     804                     <li>D.6.4&nbsp;&nbsp;&nbsp;<a href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></li>
     805                     <li>D.6.5&nbsp;&nbsp;&nbsp;<a href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></li>
     806                     <li>D.6.6&nbsp;&nbsp;&nbsp;<a href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></li>
     807                     <li>D.6.7&nbsp;&nbsp;&nbsp;<a href="#mhtml.line.length">MHTML and Line Length Limitations</a></li>
    801808                  </ul>
    802809               </li>
    803                <li>D.7&nbsp;&nbsp;&nbsp;<a href="#differences.between.http.and.mime">Differences between HTTP and MIME</a><ul>
    804                      <li>D.7.1&nbsp;&nbsp;&nbsp;<a href="#mime-version">MIME-Version</a></li>
    805                      <li>D.7.2&nbsp;&nbsp;&nbsp;<a href="#conversion.to.canonical.form">Conversion to Canonical Form</a></li>
    806                      <li>D.7.3&nbsp;&nbsp;&nbsp;<a href="#conversion.of.date.formats">Conversion of Date Formats</a></li>
    807                      <li>D.7.4&nbsp;&nbsp;&nbsp;<a href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></li>
    808                      <li>D.7.5&nbsp;&nbsp;&nbsp;<a href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></li>
    809                      <li>D.7.6&nbsp;&nbsp;&nbsp;<a href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></li>
    810                      <li>D.7.7&nbsp;&nbsp;&nbsp;<a href="#mhtml.line.length">MHTML and Line Length Limitations</a></li>
    811                   </ul>
    812                </li>
    813                <li>D.8&nbsp;&nbsp;&nbsp;<a href="#additional.features">Additional Features</a></li>
    814                <li>D.9&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616-3">Changes from RFC 2616</a></li>
    815                <li>D.10&nbsp;&nbsp;&nbsp;<a href="#change.log3">Change Log (to be removed by RFC Editor before publication)</a><ul>
    816                      <li>D.10.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.10.1">Since RFC 2616</a></li>
    817                      <li>D.10.2&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.10.2">Since draft-ietf-httpbis-p3-payload-00</a></li>
    818                      <li>D.10.3&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.10.3">Since draft-ietf-httpbis-p3-payload-01</a></li>
    819                      <li>D.10.4&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.02">Since draft-ietf-httpbis-p3-payload-02</a></li>
    820                      <li>D.10.5&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.03">Since draft-ietf-httpbis-p3-payload-03</a></li>
    821                      <li>D.10.6&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.04">Since draft-ietf-httpbis-p3-payload-04</a></li>
    822                      <li>D.10.7&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.05">Since draft-ietf-httpbis-p3-payload-05</a></li>
    823                      <li>D.10.8&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.06">Since draft-ietf-httpbis-p3-payload-06</a></li>
    824                      <li>D.10.9&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.07">Since draft-ietf-httpbis-p3-payload-07</a></li>
    825                      <li>D.10.10&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.08">Since draft-ietf-httpbis-p3-payload-08</a></li>
    826                      <li>D.10.11&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.09">Since draft-ietf-httpbis-p3-payload-09</a></li>
    827                      <li>D.10.12&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.10">Since draft-ietf-httpbis-p3-payload-10</a></li>
    828                      <li>D.10.13&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.11">Since draft-ietf-httpbis-p3-payload-11</a></li>
    829                      <li>D.10.14&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.12">Since draft-ietf-httpbis-p3-payload-12</a></li>
    830                      <li>D.10.15&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.13">Since draft-ietf-httpbis-p3-payload-13</a></li>
    831                      <li>D.10.16&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.14">Since draft-ietf-httpbis-p3-payload-14</a></li>
    832                      <li>D.10.17&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.15">Since draft-ietf-httpbis-p3-payload-15</a></li>
    833                      <li>D.10.18&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.16">Since draft-ietf-httpbis-p3-payload-16</a></li>
    834                      <li>D.10.19&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.17">Since draft-ietf-httpbis-p3-payload-17</a></li>
    835                      <li>D.10.20&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.18">Since draft-ietf-httpbis-p3-payload-18</a></li>
    836                      <li>D.10.21&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.19">Since draft-ietf-httpbis-p3-payload-19</a></li>
     810               <li>D.7&nbsp;&nbsp;&nbsp;<a href="#additional.features">Additional Features</a></li>
     811               <li>D.8&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616-3">Changes from RFC 2616</a></li>
     812               <li>D.9&nbsp;&nbsp;&nbsp;<a href="#change.log3">Change Log (to be removed by RFC Editor before publication)</a><ul>
     813                     <li>D.9.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.9.1">Since RFC 2616</a></li>
     814                     <li>D.9.2&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.9.2">Since draft-ietf-httpbis-p3-payload-00</a></li>
     815                     <li>D.9.3&nbsp;&nbsp;&nbsp;<a href="#rfc.section.D.9.3">Since draft-ietf-httpbis-p3-payload-01</a></li>
     816                     <li>D.9.4&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.02">Since draft-ietf-httpbis-p3-payload-02</a></li>
     817                     <li>D.9.5&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.03">Since draft-ietf-httpbis-p3-payload-03</a></li>
     818                     <li>D.9.6&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.04">Since draft-ietf-httpbis-p3-payload-04</a></li>
     819                     <li>D.9.7&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.05">Since draft-ietf-httpbis-p3-payload-05</a></li>
     820                     <li>D.9.8&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.06">Since draft-ietf-httpbis-p3-payload-06</a></li>
     821                     <li>D.9.9&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.07">Since draft-ietf-httpbis-p3-payload-07</a></li>
     822                     <li>D.9.10&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.08">Since draft-ietf-httpbis-p3-payload-08</a></li>
     823                     <li>D.9.11&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.09">Since draft-ietf-httpbis-p3-payload-09</a></li>
     824                     <li>D.9.12&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.10">Since draft-ietf-httpbis-p3-payload-10</a></li>
     825                     <li>D.9.13&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.11">Since draft-ietf-httpbis-p3-payload-11</a></li>
     826                     <li>D.9.14&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.12">Since draft-ietf-httpbis-p3-payload-12</a></li>
     827                     <li>D.9.15&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.13">Since draft-ietf-httpbis-p3-payload-13</a></li>
     828                     <li>D.9.16&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.14">Since draft-ietf-httpbis-p3-payload-14</a></li>
     829                     <li>D.9.17&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.15">Since draft-ietf-httpbis-p3-payload-15</a></li>
     830                     <li>D.9.18&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.16">Since draft-ietf-httpbis-p3-payload-16</a></li>
     831                     <li>D.9.19&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.17">Since draft-ietf-httpbis-p3-payload-17</a></li>
     832                     <li>D.9.20&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.18">Since draft-ietf-httpbis-p3-payload-18</a></li>
     833                     <li>D.9.21&nbsp;&nbsp;&nbsp;<a href="#changes.3.since.19">Since draft-ietf-httpbis-p3-payload-19</a></li>
    837834                  </ul>
    838835               </li>
    … …  
    918915      </p>
    919916      <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.g.1"></span>  <a href="#methods" class="smpl">method</a>         = <a href="#core.rules" class="smpl">token</a>
    920 </pre><p id="rfc.section.2.p.3">The list of methods allowed by a resource can be specified in an Allow header field (<a href="#header.allow" id="rfc.xref.header.allow.1" title="Allow">Section&nbsp;7.1</a>). The status code of the response always notifies the client whether a method is currently allowed on a resource, since the
     917</pre><p id="rfc.section.2.p.3">The list of methods allowed by a resource can be specified in an Allow header field (<a href="#header.allow" id="rfc.xref.header.allow.1" title="Allow">Section&nbsp;7.5</a>). The status code of the response always notifies the client whether a method is currently allowed on a resource, since the
    921918         set of allowed methods can change dynamically. An origin server <em class="bcp14">SHOULD</em> respond with the status code 405 (Method Not Allowed) if the method is known by the origin server but not allowed for the
    922919         resource, and 501 (Not Implemented) if the method is unrecognized or not implemented by the origin server. The methods GET
    … …  
    998995         but might be defined by future extensions to HTTP. Content negotiation <em class="bcp14">MAY</em> be used to select the appropriate response format. If no response body is included, the response <em class="bcp14">MUST</em> include a Content-Length field with a field-value of "0".
    999996      </p>
    1000       <p id="rfc.section.2.3.1.p.7">The Max-Forwards header field <em class="bcp14">MAY</em> be used to target a specific proxy in the request chain (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.1" title="Max-Forwards">Section&nbsp;7.6</a>). If no Max-Forwards field is present in the request, then the forwarded request <em class="bcp14">MUST NOT</em> include a Max-Forwards field.
     997      <p id="rfc.section.2.3.1.p.7">The Max-Forwards header field <em class="bcp14">MAY</em> be used to target a specific proxy in the request chain (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.1" title="Max-Forwards">Section&nbsp;7.14</a>). If no Max-Forwards field is present in the request, then the forwarded request <em class="bcp14">MUST NOT</em> include a Max-Forwards field.
    1001998      </p>
    1002999      <h3 id="rfc.section.2.3.2"><a href="#rfc.section.2.3.2">2.3.2</a>&nbsp;<a id="GET" href="#GET">GET</a></h3>
    … …  
    10561053      </p>
    10571054      <p id="rfc.section.2.3.4.p.4">If a resource has been created on the origin server, the response <em class="bcp14">SHOULD</em> be 201 (Created) and contain a representation which describes the status of the request and refers to the new resource, and
    1058          a Location header field (see <a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section&nbsp;7.5</a>).
    1059       </p>
    1060       <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&nbsp;D.4.7</a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.
     1055         a Location header field (see <a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section&nbsp;7.13</a>).
     1056      </p>
     1057      <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">Section&nbsp;7.8</a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.
    10611058      </p>
    10621059      <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
    … …  
    11461143      <div id="rfc.iref.m.7"></div>
    11471144      <p id="rfc.section.2.3.7.p.1">The TRACE method requests a remote, application-layer loop-back of the request message. The final recipient of the request <em class="bcp14">SHOULD</em> reflect the message received back to the client as the message body of a 200 (OK) response. The final recipient is either
    1148          the origin server or the first proxy to receive a Max-Forwards value of zero (0) in the request (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.2" title="Max-Forwards">Section&nbsp;7.6</a>). A TRACE request <em class="bcp14">MUST NOT</em> include a message body.
     1145         the origin server or the first proxy to receive a Max-Forwards value of zero (0) in the request (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.2" title="Max-Forwards">Section&nbsp;7.14</a>). A TRACE request <em class="bcp14">MUST NOT</em> include a message body.
    11491146      </p>
    11501147      <p id="rfc.section.2.3.7.p.2">TRACE allows the client to see what is being received at the other end of the request chain and use that data for testing
    … …  
    12211218         double quotes will likely cause unnecessary confusion.
    12221219      </p>
    1223       <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&nbsp;D.4.8</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing
     1220      <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">Section&nbsp;7.9</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing
    12241221         parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for
    12251222         it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Section&nbsp;6.5</a>).
    … …  
    12781275               <tr>
    12791276                  <td class="left">Accept</td>
    1280                   <td class="left"><a href="#header.accept" id="rfc.xref.header.accept.1" title="Accept">Appendix&nbsp;D.4.1</a></td>
     1277                  <td class="left"><a href="#header.accept" id="rfc.xref.header.accept.1" title="Accept">Section&nbsp;7.1</a></td>
    12811278               </tr>
    12821279               <tr>
    12831280                  <td class="left">Accept-Charset</td>
    1284                   <td class="left"><a href="#header.accept-charset" id="rfc.xref.header.accept-charset.1" title="Accept-Charset">Appendix&nbsp;D.4.2</a></td>
     1281                  <td class="left"><a href="#header.accept-charset" id="rfc.xref.header.accept-charset.1" title="Accept-Charset">Section&nbsp;7.2</a></td>
    12851282               </tr>
    12861283               <tr>
    12871284                  <td class="left">Accept-Encoding</td>
    1288                   <td class="left"><a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.1" title="Accept-Encoding">Appendix&nbsp;D.4.3</a></td>
     1285                  <td class="left"><a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.1" title="Accept-Encoding">Section&nbsp;7.3</a></td>
    12891286               </tr>
    12901287               <tr>
    12911288                  <td class="left">Accept-Language</td>
    1292                   <td class="left"><a href="#header.accept-language" id="rfc.xref.header.accept-language.1" title="Accept-Language">Appendix&nbsp;D.4.4</a></td>
     1289                  <td class="left"><a href="#header.accept-language" id="rfc.xref.header.accept-language.1" title="Accept-Language">Section&nbsp;7.4</a></td>
    12931290               </tr>
    12941291               <tr>
    … …  
    12981295               <tr>
    12991296                  <td class="left">Expect</td>
    1300                   <td class="left"><a href="#header.expect" id="rfc.xref.header.expect.1" title="Expect">Section&nbsp;7.3</a></td>
     1297                  <td class="left"><a href="#header.expect" id="rfc.xref.header.expect.1" title="Expect">Section&nbsp;7.11</a></td>
    13011298               </tr>
    13021299               <tr>
    13031300                  <td class="left">From</td>
    1304                   <td class="left"><a href="#header.from" id="rfc.xref.header.from.1" title="From">Section&nbsp;7.4</a></td>
     1301                  <td class="left"><a href="#header.from" id="rfc.xref.header.from.1" title="From">Section&nbsp;7.12</a></td>
    13051302               </tr>
    13061303               <tr>
    … …  
    13301327               <tr>
    13311328                  <td class="left">Max-Forwards</td>
    1332                   <td class="left"><a href="#header.max-forwards" id="rfc.xref.header.max-forwards.3" title="Max-Forwards">Section&nbsp;7.6</a></td>
     1329                  <td class="left"><a href="#header.max-forwards" id="rfc.xref.header.max-forwards.3" title="Max-Forwards">Section&nbsp;7.14</a></td>
    13331330               </tr>
    13341331               <tr>
    … …  
    13421339               <tr>
    13431340                  <td class="left">Referer</td>
    1344                   <td class="left"><a href="#header.referer" id="rfc.xref.header.referer.1" title="Referer">Section&nbsp;7.7</a></td>
     1341                  <td class="left"><a href="#header.referer" id="rfc.xref.header.referer.1" title="Referer">Section&nbsp;7.15</a></td>
    13451342               </tr>
    13461343               <tr>
    … …  
    13501347               <tr>
    13511348                  <td class="left">User-Agent</td>
    1352                   <td class="left"><a href="#header.user-agent" id="rfc.xref.header.user-agent.1" title="User-Agent">Section&nbsp;7.10</a></td>
     1349                  <td class="left"><a href="#header.user-agent" id="rfc.xref.header.user-agent.1" title="User-Agent">Section&nbsp;7.18</a></td>
    13531350               </tr>
    13541351            </tbody>
    … …  
    13781375               <tr>
    13791376                  <td class="left">Allow</td>
    1380                   <td class="left"><a href="#header.allow" id="rfc.xref.header.allow.2" title="Allow">Section&nbsp;7.1</a></td>
     1377                  <td class="left"><a href="#header.allow" id="rfc.xref.header.allow.2" title="Allow">Section&nbsp;7.5</a></td>
    13811378               </tr>
    13821379               <tr>
    13831380                  <td class="left">Date</td>
    1384                   <td class="left"><a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;7.2</a></td>
     1381                  <td class="left"><a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;7.10</a></td>
    13851382               </tr>
    13861383               <tr>
    … …  
    13901387               <tr>
    13911388                  <td class="left">Location</td>
    1392                   <td class="left"><a href="#header.location" id="rfc.xref.header.location.2" title="Location">Section&nbsp;7.5</a></td>
     1389                  <td class="left"><a href="#header.location" id="rfc.xref.header.location.2" title="Location">Section&nbsp;7.13</a></td>
    13931390               </tr>
    13941391               <tr>
    … …  
    13981395               <tr>
    13991396                  <td class="left">Retry-After</td>
    1400                   <td class="left"><a href="#header.retry-after" id="rfc.xref.header.retry-after.1" title="Retry-After">Section&nbsp;7.8</a></td>
     1397                  <td class="left"><a href="#header.retry-after" id="rfc.xref.header.retry-after.1" title="Retry-After">Section&nbsp;7.16</a></td>
    14011398               </tr>
    14021399               <tr>
    14031400                  <td class="left">Server</td>
    1404                   <td class="left"><a href="#header.server" id="rfc.xref.header.server.1" title="Server">Section&nbsp;7.9</a></td>
     1401                  <td class="left"><a href="#header.server" id="rfc.xref.header.server.1" title="Server">Section&nbsp;7.17</a></td>
    14051402               </tr>
    14061403               <tr>
    … …  
    14341431      </ul>
    14351432      <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
    1436          media type (<a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Appendix&nbsp;D.4.8</a>).
     1433         media type (<a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Section&nbsp;7.9</a>).
    14371434      </p>
    14381435      <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="overview.of.status.codes" href="#overview.of.status.codes">Overview of Status Codes</a></h2>
    … …  
    18301827         </p>
    18311828      </div>
    1832       <p id="rfc.section.4.5.p.4">A Location header field on a 3xx response indicates that a client <em class="bcp14">MAY</em> automatically redirect to the URI provided; see <a href="#header.location" id="rfc.xref.header.location.3" title="Location">Section&nbsp;7.5</a>.
     1829      <p id="rfc.section.4.5.p.4">A Location header field on a 3xx response indicates that a client <em class="bcp14">MAY</em> automatically redirect to the URI provided; see <a href="#header.location" id="rfc.xref.header.location.3" title="Location">Section&nbsp;7.13</a>.
    18331830      </p>
    18341831      <p id="rfc.section.4.5.p.5">Note that for methods not known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;2.1.1</a>, automatic redirection needs to done with care, since the redirect might change the conditions under which the request was
    … …  
    20462043      <div id="rfc.iref.s.31"></div>
    20472044      <h3 id="rfc.section.4.6.14"><a href="#rfc.section.4.6.14">4.6.14</a>&nbsp;<a id="status.417" href="#status.417">417 Expectation Failed</a></h3>
    2048       <p id="rfc.section.4.6.14.p.1">The expectation given in an Expect header field (see <a href="#header.expect" id="rfc.xref.header.expect.2" title="Expect">Section&nbsp;7.3</a>) could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could
     2045      <p id="rfc.section.4.6.14.p.1">The expectation given in an Expect header field (see <a href="#header.expect" id="rfc.xref.header.expect.2" title="Expect">Section&nbsp;7.11</a>) could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could
    20492046         not be met by the next-hop server.
    20502047      </p>
    … …  
    20912088      <p id="rfc.section.4.7.4.p.1">The server is currently unable to handle the request due to a temporary overloading or maintenance of the server.</p>
    20922089      <p id="rfc.section.4.7.4.p.2">The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the
    2093          delay <em class="bcp14">MAY</em> be indicated in a Retry-After header field (<a href="#header.retry-after" id="rfc.xref.header.retry-after.2" title="Retry-After">Section&nbsp;7.8</a>). If no Retry-After is given, the client <em class="bcp14">SHOULD</em> handle the response as it would for a 500 response.
     2090         delay <em class="bcp14">MAY</em> be indicated in a Retry-After header field (<a href="#header.retry-after" id="rfc.xref.header.retry-after.2" title="Retry-After">Section&nbsp;7.16</a>). If no Retry-After is given, the client <em class="bcp14">SHOULD</em> handle the response as it would for a 500 response.
    20942091      </p>
    20952092      <div class="note" id="rfc.section.4.7.4.p.3">
    … …  
    22712268      </p>
    22722269      <div id="rfc.figure.u.18"></div><pre class="inline"><span id="rfc.iref.g.22"></span>  <a href="#content.codings" class="smpl">content-coding</a>   = <a href="#core.rules" class="smpl">token</a>
    2273 </pre><p id="rfc.section.6.4.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.2" title="Accept-Encoding">Appendix&nbsp;D.4.3</a>) and Content-Encoding (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Appendix&nbsp;D.4.5</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding
     2270</pre><p id="rfc.section.6.4.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.2" title="Accept-Encoding">Section&nbsp;7.3</a>) and Content-Encoding (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Section&nbsp;7.6</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding
    22742271         mechanism will be required to remove the encoding.
    22752272      </p>
    … …  
    23082305      </p>
    23092306      <h2 id="rfc.section.6.5"><a href="#rfc.section.6.5">6.5</a>&nbsp;<a id="media.types" href="#media.types">Media Types</a></h2>
    2310       <p id="rfc.section.6.5.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.3" title="Content-Type">Appendix&nbsp;D.4.8</a>) and Accept (<a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Appendix&nbsp;D.4.1</a>) header fields in order to provide open and extensible data typing and type negotiation.
     2307      <p id="rfc.section.6.5.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.3" title="Content-Type">Section&nbsp;7.9</a>) and Accept (<a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Section&nbsp;7.1</a>) header fields in order to provide open and extensible data typing and type negotiation.
    23112308      </p>
    23122309      <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.24"></span><span id="rfc.iref.g.25"></span><span id="rfc.iref.g.26"></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> )
    … …  
    23772374      </p>
    23782375      <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1>
    2379       <p id="rfc.section.7.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to request and response semantics.</p>
     2376      <p id="rfc.section.7.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to request and response semantics and to the
     2377         payload of messages.
     2378      </p>
    23802379      <div id="rfc.iref.a.1"></div>
    23812380      <div id="rfc.iref.h.2"></div>
    2382       <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a id="header.allow" href="#header.allow">Allow</a></h2>
    2383       <p id="rfc.section.7.1.p.1">The "Allow" header field lists the set of methods advertised as supported by the target resource. The purpose of this field
     2381      <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a id="header.accept" href="#header.accept">Accept</a></h2>
     2382      <p id="rfc.section.7.1.p.1">The "Accept" header field can be used by user agents to specify response media types that are acceptable. Accept header fields
     2383         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
     2384         for an in-line image.
     2385      </p>
     2386      <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.31"></span><span id="rfc.iref.g.32"></span><span id="rfc.iref.g.33"></span><span id="rfc.iref.g.34"></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> ] )
     2387 
     2388  <a href="#header.accept" class="smpl">media-range</a>    = ( "*/*"
     2389                   / ( <a href="#media.types" class="smpl">type</a> "/" "*" )
     2390                   / ( <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> )
     2391                   ) *( <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> )
     2392  <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> )
     2393  <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> ]
     2394</pre><p id="rfc.section.7.1.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating
     2395         all subtypes of that type. The media-range <em class="bcp14">MAY</em> include media type parameters that are applicable to that range.
     2396      </p>
     2397      <p id="rfc.section.7.1.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
     2398         "q" parameter (if any) separates the media-range parameter(s) from the accept-params. Quality factors allow the user or user
     2399         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.Part1.44"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). The default value is q=1.
     2400      </p>
     2401      <div class="note" id="rfc.section.7.1.p.5">
     2402         <p> <b>Note:</b> Use of the "q" parameter name to separate media type parameters from Accept extension parameters is due to historical practice.
     2403            Although this prevents any media type parameter named "q" from being used with a media range, such an event is believed to
     2404            be unlikely given the lack of any "q" parameters in the IANA media type registry and the rare usage of any media type parameters
     2405            in Accept. Future media types are discouraged from registering any parameter named "q".
     2406         </p>
     2407      </div>
     2408      <p id="rfc.section.7.1.p.6">The example</p>
     2409      <div id="rfc.figure.u.24"></div><pre class="text">  Accept: audio/*; q=0.2, audio/basic
     2410</pre><p id="rfc.section.7.1.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
     2411         quality".
     2412      </p>
     2413      <p id="rfc.section.7.1.p.9">A request without any Accept header field implies that the user agent will accept any media type in response. If an Accept
     2414         header field is present in a request and none of the available representations for the response have a media type that is
     2415         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
     2416         the response as if it is not subject to content negotiation.
     2417      </p>
     2418      <p id="rfc.section.7.1.p.10">A more elaborate example is</p>
     2419      <div id="rfc.figure.u.25"></div><pre class="text">  Accept: text/plain; q=0.5, text/html,
     2420          text/x-dvi; q=0.8, text/x-c
     2421</pre><p id="rfc.section.7.1.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
     2422         send the text/x-dvi representation, and if that does not exist, send the text/plain representation".
     2423      </p>
     2424      <p id="rfc.section.7.1.p.13">Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies
     2425         to a given type, the most specific reference has precedence. For example,
     2426      </p>
     2427      <div id="rfc.figure.u.26"></div><pre class="text">  Accept: text/*, text/plain, text/plain;format=flowed, */*
     2428</pre><p id="rfc.section.7.1.p.15">have the following precedence: </p>
     2429      <ol>
     2430         <li>text/plain;format=flowed</li>
     2431         <li>text/plain</li>
     2432         <li>text/*</li>
     2433         <li>*/*</li>
     2434      </ol>
     2435      <p id="rfc.section.7.1.p.16">The media type quality factor associated with a given type is determined by finding the media range with the highest precedence
     2436         which matches that type. For example,
     2437      </p>
     2438      <div id="rfc.figure.u.27"></div><pre class="text">  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
     2439          text/html;level=2;q=0.4, */*;q=0.5
     2440</pre><p id="rfc.section.7.1.p.18">would cause the following values to be associated:</p>
     2441      <div id="rfc.table.u.4">
     2442         <table class="tt full left" cellpadding="3" cellspacing="0">
     2443            <thead>
     2444               <tr>
     2445                  <th>Media Type</th>
     2446                  <th>Quality Value</th>
     2447               </tr>
     2448            </thead>
     2449            <tbody>
     2450               <tr>
     2451                  <td class="left">text/html;level=1</td>
     2452                  <td class="left">1</td>
     2453               </tr>
     2454               <tr>
     2455                  <td class="left">text/html</td>
     2456                  <td class="left">0.7</td>
     2457               </tr>
     2458               <tr>
     2459                  <td class="left">text/plain</td>
     2460                  <td class="left">0.3</td>
     2461               </tr>
     2462               <tr>
     2463                  <td class="left">image/jpeg</td>
     2464                  <td class="left">0.5</td>
     2465               </tr>
     2466               <tr>
     2467                  <td class="left">text/html;level=2</td>
     2468                  <td class="left">0.4</td>
     2469               </tr>
     2470               <tr>
     2471                  <td class="left">text/html;level=3</td>
     2472                  <td class="left">0.7</td>
     2473               </tr>
     2474            </tbody>
     2475         </table>
     2476      </div>
     2477      <p id="rfc.section.7.1.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
     2478         is a closed system which cannot interact with other rendering agents, this default set ought to be configurable by the user.
     2479      </p>
     2480      <div id="rfc.iref.a.2"></div>
     2481      <div id="rfc.iref.h.3"></div>
     2482      <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a id="header.accept-charset" href="#header.accept-charset">Accept-Charset</a></h2>
     2483      <p id="rfc.section.7.2.p.1">The "Accept-Charset" header field can be used by user agents to indicate what character encodings are acceptable in a response
     2484         payload. This field allows clients capable of understanding more comprehensive or special-purpose character encodings to signal
     2485         that capability to a server which is capable of representing documents in those character encodings.
     2486      </p>
     2487      <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.35"></span>  <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = 1#( ( <a href="#rule.charset" class="smpl">charset</a> / "*" )
     2488                         [ <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> ] )
     2489</pre><p id="rfc.section.7.2.p.3">Character encoding values (a.k.a., charsets) are described in <a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;6.3</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
     2490         example is
     2491      </p>
     2492      <div id="rfc.figure.u.29"></div><pre class="text">  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
     2493</pre><p id="rfc.section.7.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere
     2494         in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then all character encodings not explicitly
     2495         mentioned get a quality value of 0.
     2496      </p>
     2497      <p id="rfc.section.7.2.p.6">A request without any Accept-Charset header field implies that the user agent will accept any character encoding in response.
     2498         If an Accept-Charset header field is present in a request and none of the available representations for the response have
     2499         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
     2500         field by treating the response as if it is not subject to content negotiation.
     2501      </p>
     2502      <div id="rfc.iref.a.3"></div>
     2503      <div id="rfc.iref.h.4"></div>
     2504      <h2 id="rfc.section.7.3"><a href="#rfc.section.7.3">7.3</a>&nbsp;<a id="header.accept-encoding" href="#header.accept-encoding">Accept-Encoding</a></h2>
     2505      <p id="rfc.section.7.3.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">Section&nbsp;6.4</a>) are acceptable in the response. An "identity" token is used as a synonym for "no encoding" in order to communicate when
     2506         no encoding is preferred.
     2507      </p>
     2508      <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.36"></span><span id="rfc.iref.g.37"></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> ] )
     2509  <a href="#header.accept-encoding" class="smpl">codings</a>          = <a href="#content.codings" class="smpl">content-coding</a> / "identity" / "*"
     2510</pre><p id="rfc.section.7.3.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.
     2511      </p>
     2512      <p id="rfc.section.7.3.p.4">For example,</p>
     2513      <div id="rfc.figure.u.31"></div><pre class="text">  Accept-Encoding: compress, gzip
     2514  Accept-Encoding:
     2515  Accept-Encoding: *
     2516  Accept-Encoding: compress;q=0.5, gzip;q=1.0
     2517  Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
     2518</pre><p id="rfc.section.7.3.p.6">A server tests whether a content-coding for a given representation is acceptable, according to an Accept-Encoding field, using
     2519         these rules:
     2520      </p>
     2521      <ol>
     2522         <li>The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed in the header
     2523            field.
     2524         </li>
     2525         <li>If the representation has no content-coding, then it is acceptable by default unless specifically excluded by the Accept-Encoding
     2526            field stating either "identity;q=0" or "*;q=0" without a more specific entry for "identity".
     2527         </li>
     2528         <li>If the representation's content-coding is one of the content-codings listed in the Accept-Encoding field, then it is acceptable
     2529            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.Part1.45"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, a qvalue of 0 means "not acceptable".)
     2530         </li>
     2531         <li>If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero qvalue is preferred.</li>
     2532      </ol>
     2533      <p id="rfc.section.7.3.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
     2534         in response. If an Accept-Encoding header field is present in a request and none of the available representations for the
     2535         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.
     2536      </p>
     2537      <p id="rfc.section.7.3.p.8">A request without an Accept-Encoding header field implies that the user agent will accept any content-coding in response,
     2538         but a representation without content-coding is preferred for compatibility with the widest variety of user agents.
     2539      </p>
     2540      <div class="note" id="rfc.section.7.3.p.9">
     2541         <p> <b>Note:</b> Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. This means that qvalues will
     2542            not work and are not permitted with x-gzip or x-compress.
     2543         </p>
     2544      </div>
     2545      <div id="rfc.iref.a.4"></div>
     2546      <div id="rfc.iref.h.5"></div>
     2547      <h2 id="rfc.section.7.4"><a href="#rfc.section.7.4">7.4</a>&nbsp;<a id="header.accept-language" href="#header.accept-language">Accept-Language</a></h2>
     2548      <p id="rfc.section.7.4.p.1">The "Accept-Language" header field can be used by user agents to indicate the set of natural languages that are preferred
     2549         in the response. Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;6.6</a>.
     2550      </p>
     2551      <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span>  <a href="#header.accept-language" class="smpl">Accept-Language</a> =
     2552                    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> ] )
     2553  <a href="#header.accept-language" class="smpl">language-range</a>  =
     2554            &lt;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>&gt;
     2555</pre><p id="rfc.section.7.4.p.3">Each language-range can be given an associated quality value which represents an estimate of the user's preference for the
     2556         languages specified by that range. The quality value defaults to "q=1". For example,
     2557      </p>
     2558      <div id="rfc.figure.u.33"></div><pre class="text">  Accept-Language: da, en-gb;q=0.8, en;q=0.7
     2559</pre><p id="rfc.section.7.4.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>)
     2560      </p>
     2561      <p id="rfc.section.7.4.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.
     2562      </p>
     2563      <div class="note" id="rfc.section.7.4.p.7">
     2564         <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.RFC2616.3"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
     2565         </p>
     2566      </div>
     2567      <p id="rfc.section.7.4.p.8">It might be contrary to the privacy expectations of the user to send an Accept-Language header field with the complete linguistic
     2568         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&nbsp;D.5.1</a>.
     2569      </p>
     2570      <p id="rfc.section.7.4.p.9">As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice
     2571         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.
     2572      </p>
     2573      <div class="note" id="rfc.section.7.4.p.10">
     2574         <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
     2575            familiar with the details of language matching as described above, and ought to be provided appropriate guidance. As an example,
     2576            users might assume that on selecting "en-gb", they will be served any kind of English document if British English is not available.
     2577            A user agent might suggest in such a case to add "en" to get the best matching behavior.
     2578         </p>
     2579      </div>
     2580      <div id="rfc.iref.a.5"></div>
     2581      <div id="rfc.iref.h.6"></div>
     2582      <h2 id="rfc.section.7.5"><a href="#rfc.section.7.5">7.5</a>&nbsp;<a id="header.allow" href="#header.allow">Allow</a></h2>
     2583      <p id="rfc.section.7.5.p.1">The "Allow" header field lists the set of methods advertised as supported by the target resource. The purpose of this field
    23842584         is strictly to inform the recipient of valid request methods associated with the resource.
    23852585      </p>
    2386       <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.31"></span>  <a href="#header.allow" class="smpl">Allow</a> = #<a href="#methods" class="smpl">method</a>
    2387 </pre><p id="rfc.section.7.1.p.3">Example of use:</p>
    2388       <div id="rfc.figure.u.24"></div><pre class="text">  Allow: GET, HEAD, PUT
    2389 </pre><p id="rfc.section.7.1.p.5">The actual set of allowed methods is defined by the origin server at the time of each request.</p>
    2390       <p id="rfc.section.7.1.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according
     2586      <div id="rfc.figure.u.34"></div><pre class="inline"><span id="rfc.iref.g.40"></span>  <a href="#header.allow" class="smpl">Allow</a> = #<a href="#methods" class="smpl">method</a>
     2587</pre><p id="rfc.section.7.5.p.3">Example of use:</p>
     2588      <div id="rfc.figure.u.35"></div><pre class="text">  Allow: GET, HEAD, PUT
     2589</pre><p id="rfc.section.7.5.p.5">The actual set of allowed methods is defined by the origin server at the time of each request.</p>
     2590      <p id="rfc.section.7.5.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according
    23912591         to the generic message handling rules.
    23922592      </p>
     2593      <div id="rfc.iref.c.7"></div>
     2594      <div id="rfc.iref.h.7"></div>
     2595      <h2 id="rfc.section.7.6"><a href="#rfc.section.7.6">7.6</a>&nbsp;<a id="header.content-encoding" href="#header.content-encoding">Content-Encoding</a></h2>
     2596      <p id="rfc.section.7.6.p.1">The "Content-Encoding" header field indicates what content-codings have been applied to the representation beyond those inherent
     2597         in the media type, and thus what decoding mechanisms have to be applied in order to obtain the media-type referenced by the
     2598         Content-Type header field. Content-Encoding is primarily used to allow a representation to be compressed without losing the
     2599         identity of its underlying media type.
     2600      </p>
     2601      <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.41"></span>  <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = 1#<a href="#content.codings" class="smpl">content-coding</a>
     2602</pre><p id="rfc.section.7.6.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section&nbsp;6.4</a>. An example of its use is
     2603      </p>
     2604      <div id="rfc.figure.u.37"></div><pre class="text">  Content-Encoding: gzip
     2605</pre><p id="rfc.section.7.6.p.5">The content-coding is a characteristic of the representation. Typically, the representation body is stored with this encoding
     2606         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
     2607         directive is present in the message.
     2608      </p>
     2609      <p id="rfc.section.7.6.p.6">If the media type includes an inherent encoding, such as a data format that is always compressed, then that encoding would
     2610         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
     2611         would only be listed if, for some bizarre reason, it is applied a second time to form the representation. Likewise, an origin
     2612         server might choose to publish the same payload data as multiple representations that differ only in whether the coding is
     2613         defined as part of Content-Type or Content-Encoding, since some user agents will behave differently in their handling of each
     2614         response (e.g., open a "Save as ..." dialog instead of automatic decompression and rendering of content).
     2615      </p>
     2616      <p id="rfc.section.7.6.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.2" title="Content-Encoding">Section&nbsp;7.6</a>) that lists the content-coding(s) applied.
     2617      </p>
     2618      <p id="rfc.section.7.6.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.
     2619      </p>
     2620      <p id="rfc.section.7.6.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).
     2621      </p>
     2622      <div id="rfc.iref.c.8"></div>
     2623      <div id="rfc.iref.h.8"></div>
     2624      <h2 id="rfc.section.7.7"><a href="#rfc.section.7.7">7.7</a>&nbsp;<a id="header.content-language" href="#header.content-language">Content-Language</a></h2>
     2625      <p id="rfc.section.7.7.p.1">The "Content-Language" header field describes the natural language(s) of the intended audience for the representation. Note
     2626         that this might not be equivalent to all the languages used within the representation.
     2627      </p>
     2628      <div id="rfc.figure.u.38"></div><pre class="inline"><span id="rfc.iref.g.42"></span>  <a href="#header.content-language" class="smpl">Content-Language</a> = 1#<a href="#language.tags" class="smpl">language-tag</a>
     2629</pre><p id="rfc.section.7.7.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;6.6</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the
     2630         user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate
     2631         field is
     2632      </p>
     2633      <div id="rfc.figure.u.39"></div><pre class="text">  Content-Language: da
     2634</pre><p id="rfc.section.7.7.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean
     2635         that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language
     2636         it is intended.
     2637      </p>
     2638      <p id="rfc.section.7.7.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
     2639         simultaneously in the original Maori and English versions, would call for
     2640      </p>
     2641      <div id="rfc.figure.u.40"></div><pre class="text">  Content-Language: mi, en
     2642</pre><p id="rfc.section.7.7.p.8">However, just because multiple languages are present within a representation does not mean that it is intended for multiple
     2643         linguistic audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin", which is clearly
     2644         intended to be used by an English-literate audience. In this case, the Content-Language would properly only include "en".
     2645      </p>
     2646      <p id="rfc.section.7.7.p.9">Content-Language <em class="bcp14">MAY</em> be applied to any media type — it is not limited to textual documents.
     2647      </p>
     2648      <div id="rfc.iref.c.9"></div>
     2649      <div id="rfc.iref.h.9"></div>
     2650      <h2 id="rfc.section.7.8"><a href="#rfc.section.7.8">7.8</a>&nbsp;<a id="header.content-location" href="#header.content-location">Content-Location</a></h2>
     2651      <p id="rfc.section.7.8.p.1">The "Content-Location" header field supplies a URI that can be used as a specific identifier for the representation in this
     2652         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
     2653         would contain the same representation that is enclosed as payload in this message.
     2654      </p>
     2655      <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.43"></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>
     2656</pre><p id="rfc.section.7.8.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.Part1.46"><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
     2657         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.
     2658      </p>
     2659      <p id="rfc.section.7.8.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
     2660         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
     2661         when no Content-Location is provided by the server. For a state-changing request like PUT or POST, it implies that the server's
     2662         response contains the new representation of that resource, thereby distinguishing it from representations that might only
     2663         report about the action (e.g., "It worked!"). This allows authoring applications to update their local copies without the
     2664         need for a subsequent GET request.
     2665      </p>
     2666      <p id="rfc.section.7.8.p.5">If Content-Location is included in a response message and its value differs from the effective request URI, then the origin
     2667         server is informing recipients that this representation has its own, presumably more specific, identifier. For a GET or HEAD
     2668         request, this is an indication that the effective request URI identifies a resource that is subject to content negotiation
     2669         and the selected representation for this response can also be found at the identified URI. For other methods, such a Content-Location
     2670         indicates that this representation contains a report on the action's status and the same report is available (for future access
     2671         with GET) at the given URI. For example, a purchase transaction made via a POST request might include a receipt document as
     2672         the payload of the 200 response; the Content-Location value provides an identifier for retrieving a copy of that same receipt
     2673         in the future.
     2674      </p>
     2675      <p id="rfc.section.7.8.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
     2676         representation (prior to any subsequent modification of the content by that user agent). In other words, the user agent is
     2677         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
     2678         resource and the origin server accepts that PUT (without redirection), then the new set of values for that resource is expected
     2679         to be consistent with the one representation supplied in that PUT; the Content-Location cannot be used as a form of reverse
     2680         content selection that identifies only one of the negotiated representations to be updated. If the user agent had wanted the
     2681         latter semantics, it would have applied the PUT directly to the Content-Location URI.
     2682      </p>
     2683      <p id="rfc.section.7.8.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
     2684         in other contexts, such as within source links or other metadata.
     2685      </p>
     2686      <p id="rfc.section.7.8.p.8">A cache cannot assume that a representation with a Content-Location different from the URI used to retrieve it can be used
     2687         to respond to later requests on that Content-Location URI.
     2688      </p>
     2689      <p id="rfc.section.7.8.p.9">If the Content-Location value is a partial URI, the partial URI is interpreted relative to the effective request URI.</p>
     2690      <div id="rfc.iref.c.10"></div>
     2691      <div id="rfc.iref.h.10"></div>
     2692      <h2 id="rfc.section.7.9"><a href="#rfc.section.7.9">7.9</a>&nbsp;<a id="header.content-type" href="#header.content-type">Content-Type</a></h2>
     2693      <p id="rfc.section.7.9.p.1">The "Content-Type" header field indicates the media type of the representation. In the case of responses to the HEAD method,
     2694         the media type is that which would have been sent had the request been a GET.
     2695      </p>
     2696      <div id="rfc.figure.u.42"></div><pre class="inline"><span id="rfc.iref.g.44"></span>  <a href="#header.content-type" class="smpl">Content-Type</a> = <a href="#media.types" class="smpl">media-type</a>
     2697</pre><p id="rfc.section.7.9.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section&nbsp;6.5</a>. An example of the field is
     2698      </p>
     2699      <div id="rfc.figure.u.43"></div><pre class="text">  Content-Type: text/html; charset=ISO-8859-4
     2700</pre><p id="rfc.section.7.9.p.5">Further discussion of Content-Type is provided in <a href="#representation.data" title="Representation Data">Appendix&nbsp;D.2.2</a>.
     2701      </p>
    23932702      <div id="rfc.iref.d.3"></div>
    2394       <div id="rfc.iref.h.3"></div>
    2395       <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a id="header.date" href="#header.date">Date</a></h2>
    2396       <p id="rfc.section.7.2.p.1">The "Date" header field represents the date and time at which the message was originated, having the same semantics as the
     2703      <div id="rfc.iref.h.11"></div>
     2704      <h2 id="rfc.section.7.10"><a href="#rfc.section.7.10">7.10</a>&nbsp;<a id="header.date" href="#header.date">Date</a></h2>
     2705      <p id="rfc.section.7.10.p.1">The "Date" header field represents the date and time at which the message was originated, having the same semantics as the
    23972706         Origination Date Field (orig-date) defined in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.1">Section 3.6.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as defined in <a href="#http.date" title="Date/Time Formats">Section&nbsp;6.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
    23982707      </p>
    2399       <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.32"></span>  <a href="#header.date" class="smpl">Date</a> = <a href="#http.date" class="smpl">HTTP-date</a>
    2400 </pre><p id="rfc.section.7.2.p.3">An example is</p>
    2401       <div id="rfc.figure.u.26"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
    2402 </pre><p id="rfc.section.7.2.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
     2708      <div id="rfc.figure.u.44"></div><pre class="inline"><span id="rfc.iref.g.45"></span>  <a href="#header.date" class="smpl">Date</a> = <a href="#http.date" class="smpl">HTTP-date</a>
     2709</pre><p id="rfc.section.7.10.p.3">An example is</p>
     2710      <div id="rfc.figure.u.45"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
     2711</pre><p id="rfc.section.7.10.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
    24032712      </p>
    24042713      <ol>
    … …  
    24112720         </li>
    24122721      </ol>
    2413       <p id="rfc.section.7.2.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient.
    2414       </p>
    2415       <p id="rfc.section.7.2.p.7">Clients can use the Date header field as well; in order to keep request messages small, they are advised not to include it
     2722      <p id="rfc.section.7.10.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient.
     2723      </p>
     2724      <p id="rfc.section.7.10.p.7">Clients can use the Date header field as well; in order to keep request messages small, they are advised not to include it
    24162725         when it doesn't convey any useful information (as is usually the case for requests that do not contain a payload).
    24172726      </p>
    2418       <p id="rfc.section.7.2.p.8">The HTTP-date sent in a Date header field <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means
     2727      <p id="rfc.section.7.10.p.8">The HTTP-date sent in a Date header field <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means
    24192728         of generating a reasonably accurate date and time. In theory, the date ought to represent the moment just before the payload
    24202729         is generated. In practice, the date can be generated at any time during the message origination without affecting its semantic
    … …  
    24222731      </p>
    24232732      <div id="rfc.iref.e.1"></div>
    2424       <div id="rfc.iref.h.4"></div>
    2425       <h2 id="rfc.section.7.3"><a href="#rfc.section.7.3">7.3</a>&nbsp;<a id="header.expect" href="#header.expect">Expect</a></h2>
    2426       <p id="rfc.section.7.3.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p>
    2427       <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.33"></span><span id="rfc.iref.g.34"></span><span id="rfc.iref.g.35"></span><span id="rfc.iref.g.36"></span><span id="rfc.iref.g.37"></span>  <a href="#header.expect" class="smpl">Expect</a>       = 1#<a href="#header.expect" class="smpl">expectation</a>
     2733      <div id="rfc.iref.h.12"></div>
     2734      <h2 id="rfc.section.7.11"><a href="#rfc.section.7.11">7.11</a>&nbsp;<a id="header.expect" href="#header.expect">Expect</a></h2>
     2735      <p id="rfc.section.7.11.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p>
     2736      <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><span id="rfc.iref.g.50"></span>  <a href="#header.expect" class="smpl">Expect</a>       = 1#<a href="#header.expect" class="smpl">expectation</a>
    24282737 
    24292738  <a href="#header.expect" class="smpl">expectation</a>  = <a href="#header.expect" class="smpl">expect-name</a> [ <a href="#core.rules" class="smpl">BWS</a> "=" <a href="#core.rules" class="smpl">BWS</a> <a href="#header.expect" class="smpl">expect-value</a> ]
    … …  
    24332742  <a href="#header.expect" class="smpl">expect-name</a>  = <a href="#core.rules" class="smpl">token</a>
    24342743  <a href="#header.expect" class="smpl">expect-value</a> = <a href="#core.rules" class="smpl">token</a> / <a href="#core.rules" class="smpl">quoted-string</a>
    2435 </pre><p id="rfc.section.7.3.p.3">If all received Expect header field(s) are syntactically valid but contain an expectation that the recipient does not understand
     2744</pre><p id="rfc.section.7.11.p.3">If all received Expect header field(s) are syntactically valid but contain an expectation that the recipient does not understand
    24362745         or cannot comply with, the recipient <em class="bcp14">MUST</em> respond with a 417 (Expectation Failed) status code. A recipient of a syntactically invalid Expectation header field <em class="bcp14">MUST</em> respond with a 4xx status code other than 417.
    24372746      </p>
    2438       <p id="rfc.section.7.3.p.4">The only expectation defined by this specification is:</p>
    2439       <p id="rfc.section.7.3.p.5"><span id="rfc.iref.103"></span><span id="rfc.iref.e.2"></span> 100-continue
     2747      <p id="rfc.section.7.11.p.4">The only expectation defined by this specification is:</p>
     2748      <p id="rfc.section.7.11.p.5"><span id="rfc.iref.132"></span><span id="rfc.iref.e.2"></span> 100-continue
    24402749      </p>
    24412750      <ul class="empty">
    2442          <li>The "100-continue" expectation is defined <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.4.3</a> of <a href="#Part1" id="rfc.xref.Part1.44"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. It does not support any expect-params.
    2443          </li>
    2444       </ul>
    2445       <p id="rfc.section.7.3.p.6">Comparison is case-insensitive for names (expect-name), and case-sensitive for values (expect-value).</p>
    2446       <p id="rfc.section.7.3.p.7">The Expect mechanism is hop-by-hop: the above requirements apply to any server, including proxies. However, the Expect header
     2751         <li>The "100-continue" expectation is defined <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.4.3</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>. It does not support any expect-params.
     2752         </li>
     2753      </ul>
     2754      <p id="rfc.section.7.11.p.6">Comparison is case-insensitive for names (expect-name), and case-sensitive for values (expect-value).</p>
     2755      <p id="rfc.section.7.11.p.7">The Expect mechanism is hop-by-hop: the above requirements apply to any server, including proxies. However, the Expect header
    24472756         field itself is end-to-end; it <em class="bcp14">MUST</em> be forwarded if the request is forwarded.
    24482757      </p>
    2449       <p id="rfc.section.7.3.p.8">Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header field.</p>
     2758      <p id="rfc.section.7.11.p.8">Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header field.</p>
    24502759      <div id="rfc.iref.f.1"></div>
    2451       <div id="rfc.iref.h.5"></div>
    2452       <h2 id="rfc.section.7.4"><a href="#rfc.section.7.4">7.4</a>&nbsp;<a id="header.from" href="#header.from">From</a></h2>
    2453       <p id="rfc.section.7.4.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>:
    2454       </p>
    2455       <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.38"></span>  <a href="#header.from" class="smpl">From</a>    = <a href="#header.from" class="smpl">mailbox</a>
     2760      <div id="rfc.iref.h.13"></div>
     2761      <h2 id="rfc.section.7.12"><a href="#rfc.section.7.12">7.12</a>&nbsp;<a id="header.from" href="#header.from">From</a></h2>
     2762      <p id="rfc.section.7.12.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>:
     2763      </p>
     2764      <div id="rfc.figure.u.47"></div><pre class="inline"><span id="rfc.iref.g.51"></span>  <a href="#header.from" class="smpl">From</a>    = <a href="#header.from" class="smpl">mailbox</a>
    24562765 
    24572766  <a href="#header.from" class="smpl">mailbox</a> = &lt;mailbox, defined in <a href="#RFC5322" id="rfc.xref.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a>&gt;
    2458 </pre><p id="rfc.section.7.4.p.3">An example is:</p>
    2459       <div id="rfc.figure.u.29"></div><pre class="text">  From: webmaster@example.org
    2460 </pre><p id="rfc.section.7.4.p.5">This header field <em class="bcp14">MAY</em> be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It <em class="bcp14">SHOULD NOT</em> be used as an insecure form of access protection. The interpretation of this field is that the request is being performed
     2767</pre><p id="rfc.section.7.12.p.3">An example is:</p>
     2768      <div id="rfc.figure.u.48"></div><pre class="text">  From: webmaster@example.org
     2769</pre><p id="rfc.section.7.12.p.5">This header field <em class="bcp14">MAY</em> be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It <em class="bcp14">SHOULD NOT</em> be used as an insecure form of access protection. The interpretation of this field is that the request is being performed
    24612770         on behalf of the person given, who accepts responsibility for the method performed. In particular, robot agents <em class="bcp14">SHOULD</em> include this header field so that the person responsible for running the robot can be contacted if problems occur on the receiving
    24622771         end.
    24632772      </p>
    2464       <p id="rfc.section.7.4.p.6">The Internet e-mail address in this field <em class="bcp14">MAY</em> be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original
     2773      <p id="rfc.section.7.12.p.6">The Internet e-mail address in this field <em class="bcp14">MAY</em> be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original
    24652774         issuer's address <em class="bcp14">SHOULD</em> be used.
    24662775      </p>
    2467       <p id="rfc.section.7.4.p.7">The client <em class="bcp14">SHOULD NOT</em> send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's
     2776      <p id="rfc.section.7.12.p.7">The client <em class="bcp14">SHOULD NOT</em> send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's
    24682777         security policy. It is strongly recommended that the user be able to disable, enable, and modify the value of this field at
    24692778         any time prior to a request.
    24702779      </p>
    24712780      <div id="rfc.iref.l.1"></div>
    2472       <div id="rfc.iref.h.6"></div>
    2473       <h2 id="rfc.section.7.5"><a href="#rfc.section.7.5">7.5</a>&nbsp;<a id="header.location" href="#header.location">Location</a></h2>
    2474       <p id="rfc.section.7.5.p.1">The "Location" header field <em class="bcp14">MAY</em> be sent in responses to refer to a specific resource in accordance with the semantics of the status code.
    2475       </p>
    2476       <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.39"></span>  <a href="#header.location" class="smpl">Location</a> = <a href="#abnf.dependencies" class="smpl">URI-reference</a>
    2477 </pre><p id="rfc.section.7.5.p.3">For 201 (Created) responses, the Location is the URI of the new resource which was created by the request. For 3xx responses,
     2781      <div id="rfc.iref.h.14"></div>
     2782      <h2 id="rfc.section.7.13"><a href="#rfc.section.7.13">7.13</a>&nbsp;<a id="header.location" href="#header.location">Location</a></h2>
     2783      <p id="rfc.section.7.13.p.1">The "Location" header field <em class="bcp14">MAY</em> be sent in responses to refer to a specific resource in accordance with the semantics of the status code.
     2784      </p>
     2785      <div id="rfc.figure.u.49"></div><pre class="inline"><span id="rfc.iref.g.52"></span>  <a href="#header.location" class="smpl">Location</a> = <a href="#abnf.dependencies" class="smpl">URI-reference</a>
     2786</pre><p id="rfc.section.7.13.p.3">For 201 (Created) responses, the Location is the URI of the new resource which was created by the request. For 3xx responses,
    24782787         the location <em class="bcp14">SHOULD</em> indicate the server's preferred URI for automatic redirection to the resource.
    24792788      </p>
    2480       <p id="rfc.section.7.5.p.4">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>). If the original URI, as navigated to by the user agent, did contain a fragment identifier, and the final value does not,
     2789      <p id="rfc.section.7.13.p.4">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>). If the original URI, as navigated to by the user agent, did contain a fragment identifier, and the final value does not,
    24812790         then the original URI's fragment identifier is added to the final value.
    24822791      </p>
    2483       <div id="rfc.figure.u.31"></div>
     2792      <div id="rfc.figure.u.50"></div>
    24842793      <p>For example, the original URI "http://www.example.org/~tim", combined with a field value given as:</p>  <pre class="text">  Location: /pub/WWW/People.html#tim
    24852794</pre>  <p>would result in a final value of "http://www.example.org/pub/WWW/People.html#tim"</p>
    2486       <div id="rfc.figure.u.32"></div>
     2795      <div id="rfc.figure.u.51"></div>
    24872796      <p>An original URI "http://www.example.org/index.html#larry", combined with a field value given as:</p>  <pre class="text">  Location: http://www.example.net/index.html
    24882797</pre>  <p>would result in a final value of "http://www.example.net/index.html#larry", preserving the original fragment identifier.</p>
    2489       <div class="note" id="rfc.section.7.5.p.7">
     2798      <div class="note" id="rfc.section.7.13.p.7">
    24902799         <p> <b>Note:</b> Some recipients attempt to recover from Location fields that are not valid URI references. This specification does not mandate
    24912800            or define such processing, but does allow it (see <a href="#intro.conformance.and.error.handling" title="Conformance and Error Handling">Section&nbsp;1.2</a>).
    24922801         </p>
    24932802      </div>
    2494       <p id="rfc.section.7.5.p.8">There are circumstances in which a fragment identifier in a Location URI would not be appropriate. For instance, when it appears
     2803      <p id="rfc.section.7.13.p.8">There are circumstances in which a fragment identifier in a Location URI would not be appropriate. For instance, when it appears
    24952804         in a 201 Created response, where the Location header field specifies the URI for the entire created resource.
    24962805      </p>
    2497       <div class="note" id="rfc.section.7.5.p.9">
    2498          <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&nbsp;D.4.7</a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.
     2806      <div class="note" id="rfc.section.7.13.p.9">
     2807         <p> <b>Note:</b> The Content-Location header field (<a href="#header.content-location" id="rfc.xref.header.content-location.2" title="Content-Location">Section&nbsp;7.8</a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.
    24992808            It is therefore possible for a response to contain header fields for both Location and Content-Location.
    25002809         </p>
    25012810      </div>
    25022811      <div id="rfc.iref.m.9"></div>
    2503       <div id="rfc.iref.h.7"></div>
    2504       <h2 id="rfc.section.7.6"><a href="#rfc.section.7.6">7.6</a>&nbsp;<a id="header.max-forwards" href="#header.max-forwards">Max-Forwards</a></h2>
    2505       <p id="rfc.section.7.6.p.1">The "Max-Forwards" header field provides a mechanism with the TRACE (<a href="#TRACE" id="rfc.xref.TRACE.1" title="TRACE">Section&nbsp;2.3.7</a>) and OPTIONS (<a href="#OPTIONS" id="rfc.xref.OPTIONS.1" title="OPTIONS">Section&nbsp;2.3.1</a>) methods to limit the number of times that the request is forwarded by proxies. This can be useful when the client is attempting
     2812      <div id="rfc.iref.h.15"></div>
     2813      <h2 id="rfc.section.7.14"><a href="#rfc.section.7.14">7.14</a>&nbsp;<a id="header.max-forwards" href="#header.max-forwards">Max-Forwards</a></h2>
     2814      <p id="rfc.section.7.14.p.1">The "Max-Forwards" header field provides a mechanism with the TRACE (<a href="#TRACE" id="rfc.xref.TRACE.1" title="TRACE">Section&nbsp;2.3.7</a>) and OPTIONS (<a href="#OPTIONS" id="rfc.xref.OPTIONS.1" title="OPTIONS">Section&nbsp;2.3.1</a>) methods to limit the number of times that the request is forwarded by proxies. This can be useful when the client is attempting
    25062815         to trace a request which appears to be failing or looping mid-chain.
    25072816      </p>
    2508       <div id="rfc.figure.u.33"></div><pre class="inline"><span id="rfc.iref.g.40"></span>  <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
    2509 </pre><p id="rfc.section.7.6.p.3">The Max-Forwards value is a decimal integer indicating the remaining number of times this request message can be forwarded.</p>
    2510       <p id="rfc.section.7.6.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1).
    2511       </p>
    2512       <p id="rfc.section.7.6.p.5">The Max-Forwards header field <em class="bcp14">MAY</em> be ignored for all other request methods.
     2817      <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.53"></span>  <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
     2818</pre><p id="rfc.section.7.14.p.3">The Max-Forwards value is a decimal integer indicating the remaining number of times this request message can be forwarded.</p>
     2819      <p id="rfc.section.7.14.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1).
     2820      </p>
     2821      <p id="rfc.section.7.14.p.5">The Max-Forwards header field <em class="bcp14">MAY</em> be ignored for all other request methods.
    25132822      </p>
    25142823      <div id="rfc.iref.r.1"></div>
    2515       <div id="rfc.iref.h.8"></div>
    2516       <h2 id="rfc.section.7.7"><a href="#rfc.section.7.7">7.7</a>&nbsp;<a id="header.referer" href="#header.referer">Referer</a></h2>
    2517       <p id="rfc.section.7.7.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the target URI was obtained
     2824      <div id="rfc.iref.h.16"></div>
     2825      <h2 id="rfc.section.7.15"><a href="#rfc.section.7.15">7.15</a>&nbsp;<a id="header.referer" href="#header.referer">Referer</a></h2>
     2826      <p id="rfc.section.7.15.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the target URI was obtained
    25182827         (the "referrer", although the header field is misspelled.).
    25192828      </p>
    2520       <p id="rfc.section.7.7.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching,
     2829      <p id="rfc.section.7.15.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching,
    25212830         etc. It also allows obsolete or mistyped links to be traced for maintenance. Some servers use Referer as a means of controlling
    25222831         where they allow links from (so-called "deep linking"), but legitimate requests do not always contain a Referer header field.
    25232832      </p>
    2524       <p id="rfc.section.7.7.p.3">If the target URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard), the Referer
     2833      <p id="rfc.section.7.15.p.3">If the target URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard), the Referer
    25252834         field <em class="bcp14">MUST</em> either be sent with the value "about:blank", or not be sent at all. Note that this requirement does not apply to sources with
    25262835         non-HTTP URIs (e.g., FTP).
    25272836      </p>
    2528       <div id="rfc.figure.u.34"></div><pre class="inline"><span id="rfc.iref.g.41"></span>  <a href="#header.referer" class="smpl">Referer</a> = <a href="#abnf.dependencies" class="smpl">absolute-URI</a> / <a href="#abnf.dependencies" class="smpl">partial-URI</a>
    2529 </pre><p id="rfc.section.7.7.p.5">Example:</p>
    2530       <div id="rfc.figure.u.35"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
    2531 </pre><p id="rfc.section.7.7.p.7">If the field value is a relative URI, it <em class="bcp14">SHOULD</em> be interpreted relative to the effective request URI. The URI <em class="bcp14">MUST NOT</em> include a fragment. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;9.2</a> for security considerations.
     2837      <div id="rfc.figure.u.53"></div><pre class="inline"><span id="rfc.iref.g.54"></span>  <a href="#header.referer" class="smpl">Referer</a> = <a href="#abnf.dependencies" class="smpl">absolute-URI</a> / <a href="#abnf.dependencies" class="smpl">partial-URI</a>
     2838</pre><p id="rfc.section.7.15.p.5">Example:</p>
     2839      <div id="rfc.figure.u.54"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
     2840</pre><p id="rfc.section.7.15.p.7">If the field value is a relative URI, it <em class="bcp14">SHOULD</em> be interpreted relative to the effective request URI. The URI <em class="bcp14">MUST NOT</em> include a fragment. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;9.2</a> for security considerations.
    25322841      </p>
    25332842      <div id="rfc.iref.r.2"></div>
    2534       <div id="rfc.iref.h.9"></div>
    2535       <h2 id="rfc.section.7.8"><a href="#rfc.section.7.8">7.8</a>&nbsp;<a id="header.retry-after" href="#header.retry-after">Retry-After</a></h2>
    2536       <p id="rfc.section.7.8.p.1">The header "Retry-After" field can be used with a 503 (Service Unavailable) response to indicate how long the service is expected
     2843      <div id="rfc.iref.h.17"></div>
     2844      <h2 id="rfc.section.7.16"><a href="#rfc.section.7.16">7.16</a>&nbsp;<a id="header.retry-after" href="#header.retry-after">Retry-After</a></h2>
     2845      <p id="rfc.section.7.16.p.1">The header "Retry-After" field can be used with a 503 (Service Unavailable) response to indicate how long the service is expected
    25372846         to be unavailable to the requesting client. This field <em class="bcp14">MAY</em> also be used with any 3xx (Redirection) response to indicate the minimum time the user-agent is asked to wait before issuing
    25382847         the redirected request.
    25392848      </p>
    2540       <p id="rfc.section.7.8.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p>
    2541       <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.42"></span>  <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#http.date" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>
     2849      <p id="rfc.section.7.16.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p>
     2850      <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.55"></span>  <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#http.date" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>
    25422851</pre><div id="rule.delta-seconds">
    2543          <p id="rfc.section.7.8.p.4">  Time spans are non-negative decimal integers, representing time in seconds.</p>
     2852         <p id="rfc.section.7.16.p.4">  Time spans are non-negative decimal integers, representing time in seconds.</p>
    25442853      </div>
    2545       <div id="rfc.figure.u.37"></div><pre class="inline"><span id="rfc.iref.g.43"></span>  <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
    2546 </pre><p id="rfc.section.7.8.p.6">Two examples of its use are</p>
    2547       <div id="rfc.figure.u.38"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
     2854      <div id="rfc.figure.u.56"></div><pre class="inline"><span id="rfc.iref.g.56"></span>  <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
     2855</pre><p id="rfc.section.7.16.p.6">Two examples of its use are</p>
     2856      <div id="rfc.figure.u.57"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
    25482857  Retry-After: 120
    2549 </pre><p id="rfc.section.7.8.p.8">In the latter example, the delay is 2 minutes.</p>
     2858</pre><p id="rfc.section.7.16.p.8">In the latter example, the delay is 2 minutes.</p>
    25502859      <div id="rfc.iref.s.39"></div>
    2551       <div id="rfc.iref.h.10"></div>
    2552       <h2 id="rfc.section.7.9"><a href="#rfc.section.7.9">7.9</a>&nbsp;<a id="header.server" href="#header.server">Server</a></h2>
    2553       <p id="rfc.section.7.9.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p>
    2554       <p id="rfc.section.7.9.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</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>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for
     2860      <div id="rfc.iref.h.18"></div>
     2861      <h2 id="rfc.section.7.17"><a href="#rfc.section.7.17">7.17</a>&nbsp;<a id="header.server" href="#header.server">Server</a></h2>
     2862      <p id="rfc.section.7.17.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p>
     2863      <p id="rfc.section.7.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</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>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for
    25552864         identifying the application.
    25562865      </p>
    2557       <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.44"></span>  <a href="#header.server" class="smpl">Server</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
    2558 </pre><p id="rfc.section.7.9.p.4">Example:</p>
    2559       <div id="rfc.figure.u.40"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
    2560 </pre><p id="rfc.section.7.9.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the Server header field. Instead, it <em class="bcp14">MUST</em> include a Via field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 6.2</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>).
    2561       </p>
    2562       <div class="note" id="rfc.section.7.9.p.7">
     2866      <div id="rfc.figure.u.58"></div><pre class="inline"><span id="rfc.iref.g.57"></span>  <a href="#header.server" class="smpl">Server</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
     2867</pre><p id="rfc.section.7.17.p.4">Example:</p>
     2868      <div id="rfc.figure.u.59"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
     2869</pre><p id="rfc.section.7.17.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the Server header field. Instead, it <em class="bcp14">MUST</em> include a Via field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 6.2</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>).
     2870      </p>
     2871      <div class="note" id="rfc.section.7.17.p.7">
    25632872         <p> <b>Note:</b> Revealing the specific software version of the server might allow the server machine to become more vulnerable to attacks
    25642873            against software that is known to contain security holes. Server implementors are encouraged to make this field a configurable
    … …  
    25672876      </div>
    25682877      <div id="rfc.iref.u.1"></div>
    2569       <div id="rfc.iref.h.11"></div>
    2570       <h2 id="rfc.section.7.10"><a href="#rfc.section.7.10">7.10</a>&nbsp;<a id="header.user-agent" href="#header.user-agent">User-Agent</a></h2>
    2571       <p id="rfc.section.7.10.p.1">The "User-Agent" header field contains information about the user agent originating the request. User agents <em class="bcp14">SHOULD</em> include this field with requests.
    2572       </p>
    2573       <p id="rfc.section.7.10.p.2">Typically, it is used for statistical purposes, the tracing of protocol violations, and tailoring responses to avoid particular
     2878      <div id="rfc.iref.h.19"></div>
     2879      <h2 id="rfc.section.7.18"><a href="#rfc.section.7.18">7.18</a>&nbsp;<a id="header.user-agent" href="#header.user-agent">User-Agent</a></h2>
     2880      <p id="rfc.section.7.18.p.1">The "User-Agent" header field contains information about the user agent originating the request. User agents <em class="bcp14">SHOULD</em> include this field with requests.
     2881      </p>
     2882      <p id="rfc.section.7.18.p.2">Typically, it is used for statistical purposes, the tracing of protocol violations, and tailoring responses to avoid particular
    25742883         user agent limitations.
    25752884      </p>
    2576       <p id="rfc.section.7.10.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</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>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance
     2885      <p id="rfc.section.7.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section&nbsp;6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 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>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance
    25772886         for identifying the application.
    25782887      </p>
    2579       <p id="rfc.section.7.10.p.4">Because this field is usually sent on every request a user agent makes, implementations are encouraged not to include needlessly
     2888      <p id="rfc.section.7.18.p.4">Because this field is usually sent on every request a user agent makes, implementations are encouraged not to include needlessly
    25802889         fine-grained detail, and to limit (or even prohibit) the addition of subproducts by third parties. Overly long and detailed
    25812890         User-Agent field values make requests larger and can also be used to identify ("fingerprint") the user against their wishes.
    25822891      </p>
    2583       <p id="rfc.section.7.10.p.5">Likewise, implementations are encouraged not to use the product tokens of other implementations in order to declare compatibility
     2892      <p id="rfc.section.7.18.p.5">Likewise, implementations are encouraged not to use the product tokens of other implementations in order to declare compatibility
    25842893         with them, as this circumvents the purpose of the field. Finally, they are encouraged not to use comments to identify products;
    25852894         doing so makes the field value more difficult to parse.
    25862895      </p>
    2587       <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.45"></span>  <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
    2588 </pre><p id="rfc.section.7.10.p.7">Example:</p>
    2589       <div id="rfc.figure.u.42"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     2896      <div id="rfc.figure.u.60"></div><pre class="inline"><span id="rfc.iref.g.58"></span>  <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
     2897</pre><p id="rfc.section.7.18.p.7">Example:</p>
     2898      <div id="rfc.figure.u.61"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    25902899</pre><h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
    25912900      <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a>&nbsp;<a id="method.registration" href="#method.registration">Method Registry</a></h2>
    … …  
    29103219                  <td class="left">http</td>
    29113220                  <td class="left">standard</td>
    2912                   <td class="left"> <a href="#header.accept" id="rfc.xref.header.accept.3" title="Accept">Appendix&nbsp;D.4.1</a>
     3221                  <td class="left"> <a href="#header.accept" id="rfc.xref.header.accept.3" title="Accept">Section&nbsp;7.1</a>
    29133222                  </td>
    29143223               </tr>
    … …  
    29173226                  <td class="left">http</td>
    29183227                  <td class="left">standard</td>
    2919                   <td class="left"> <a href="#header.accept-charset" id="rfc.xref.header.accept-charset.2" title="Accept-Charset">Appendix&nbsp;D.4.2</a>
     3228                  <td class="left"> <a href="#header.accept-charset" id="rfc.xref.header.accept-charset.2" title="Accept-Charset">Section&nbsp;7.2</a>
    29203229                  </td>
    29213230               </tr>
    … …  
    29243233                  <td class="left">http</td>
    29253234                  <td class="left">standard</td>
    2926                   <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.3" title="Accept-Encoding">Appendix&nbsp;D.4.3</a>
     3235                  <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.3" title="Accept-Encoding">Section&nbsp;7.3</a>
    29273236                  </td>
    29283237               </tr>
    … …  
    29313240                  <td class="left">http</td>
    29323241                  <td class="left">standard</td>
    2933                   <td class="left"> <a href="#header.accept-language" id="rfc.xref.header.accept-language.2" title="Accept-Language">Appendix&nbsp;D.4.4</a>
     3242                  <td class="left"> <a href="#header.accept-language" id="rfc.xref.header.accept-language.2" title="Accept-Language">Section&nbsp;7.4</a>
    29343243                  </td>
    29353244               </tr>
    … …  
    29383247                  <td class="left">http</td>
    29393248                  <td class="left">standard</td>
    2940                   <td class="left"> <a href="#header.allow" id="rfc.xref.header.allow.3" title="Allow">Section&nbsp;7.1</a>
     3249                  <td class="left"> <a href="#header.allow" id="rfc.xref.header.allow.3" title="Allow">Section&nbsp;7.5</a>
    29413250                  </td>
    29423251               </tr>
    … …  
    29453254                  <td class="left">http</td>
    29463255                  <td class="left">standard</td>
    2947                   <td class="left"> <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.2" title="Content-Encoding">Appendix&nbsp;D.4.5</a>
     3256                  <td class="left"> <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.3" title="Content-Encoding">Section&nbsp;7.6</a>
    29483257                  </td>
    29493258               </tr>
    … …  
    29523261                  <td class="left">http</td>
    29533262                  <td class="left">standard</td>
    2954                   <td class="left"> <a href="#header.content-language" id="rfc.xref.header.content-language.1" title="Content-Language">Appendix&nbsp;D.4.6</a>
     3263                  <td class="left"> <a href="#header.content-language" id="rfc.xref.header.content-language.1" title="Content-Language">Section&nbsp;7.7</a>
    29553264                  </td>
    29563265               </tr>
    … …  
    29593268                  <td class="left">http</td>
    29603269                  <td class="left">standard</td>
    2961                   <td class="left"> <a href="#header.content-location" id="rfc.xref.header.content-location.3" title="Content-Location">Appendix&nbsp;D.4.7</a>
     3270                  <td class="left"> <a href="#header.content-location" id="rfc.xref.header.content-location.3" title="Content-Location">Section&nbsp;7.8</a>
    29623271                  </td>
    29633272               </tr>
    … …  
    29663275                  <td class="left">http</td>
    29673276                  <td class="left">standard</td>
    2968                   <td class="left"> <a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Appendix&nbsp;D.4.8</a>
     3277                  <td class="left"> <a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Section&nbsp;7.9</a>
    29693278                  </td>
    29703279               </tr>
    … …  
    29733282                  <td class="left">http</td>
    29743283                  <td class="left">standard</td>
    2975                   <td class="left"> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;7.2</a>
     3284                  <td class="left"> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;7.10</a>
    29763285                  </td>
    29773286               </tr>
    … …  
    29803289                  <td class="left">http</td>
    29813290                  <td class="left">standard</td>
    2982                   <td class="left"> <a href="#header.expect" id="rfc.xref.header.expect.3" title="Expect">Section&nbsp;7.3</a>
     3291                  <td class="left"> <a href="#header.expect" id="rfc.xref.header.expect.3" title="Expect">Section&nbsp;7.11</a>
    29833292                  </td>
    29843293               </tr>
    … …  
    29873296                  <td class="left">http</td>
    29883297                  <td class="left">standard</td>
    2989                   <td class="left"> <a href="#header.from" id="rfc.xref.header.from.2" title="From">Section&nbsp;7.4</a>
     3298                  <td class="left"> <a href="#header.from" id="rfc.xref.header.from.2" title="From">Section&nbsp;7.12</a>
    29903299                  </td>
    29913300               </tr>
    … …  
    29943303                  <td class="left">http</td>
    29953304                  <td class="left">standard</td>
    2996                   <td class="left"> <a href="#header.location" id="rfc.xref.header.location.4" title="Location">Section&nbsp;7.5</a>
     3305                  <td class="left"> <a href="#header.location" id="rfc.xref.header.location.4" title="Location">Section&nbsp;7.13</a>
    29973306                  </td>
    29983307               </tr>
    … …  
    30013310                  <td class="left">http</td>
    30023311                  <td class="left">standard</td>
    3003                   <td class="left"> <a href="#mime-version" id="rfc.xref.mime-version.1" title="MIME-Version">Appendix&nbsp;D.7.1</a>
     3312                  <td class="left"> <a href="#mime-version" id="rfc.xref.mime-version.1" title="MIME-Version">Appendix&nbsp;D.6.1</a>
    30043313                  </td>
    30053314               </tr>
    … …  
    30083317                  <td class="left">http</td>
    30093318                  <td class="left">standard</td>
    3010                   <td class="left"> <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.4" title="Max-Forwards">Section&nbsp;7.6</a>
     3319                  <td class="left"> <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.4" title="Max-Forwards">Section&nbsp;7.14</a>
    30113320                  </td>
    30123321               </tr>
    … …  
    30153324                  <td class="left">http</td>
    30163325                  <td class="left">standard</td>
    3017                   <td class="left"> <a href="#header.referer" id="rfc.xref.header.referer.2" title="Referer">Section&nbsp;7.7</a>
     3326                  <td class="left"> <a href="#header.referer" id="rfc.xref.header.referer.2" title="Referer">Section&nbsp;7.15</a>
    30183327                  </td>
    30193328               </tr>
    … …  
    30223331                  <td class="left">http</td>
    30233332                  <td class="left">standard</td>
    3024                   <td class="left"> <a href="#header.retry-after" id="rfc.xref.header.retry-after.3" title="Retry-After">Section&nbsp;7.8</a>
     3333                  <td class="left"> <a href="#header.retry-after" id="rfc.xref.header.retry-after.3" title="Retry-After">Section&nbsp;7.16</a>
    30253334                  </td>
    30263335               </tr>
    … …  
    30293338                  <td class="left">http</td>
    30303339                  <td class="left">standard</td>
    3031                   <td class="left"> <a href="#header.server" id="rfc.xref.header.server.2" title="Server">Section&nbsp;7.9</a>
     3340                  <td class="left"> <a href="#header.server" id="rfc.xref.header.server.2" title="Server">Section&nbsp;7.17</a>
    30323341                  </td>
    30333342               </tr>
    … …  
    30363345                  <td class="left">http</td>
    30373346                  <td class="left">standard</td>
    3038                   <td class="left"> <a href="#header.user-agent" id="rfc.xref.header.user-agent.2" title="User-Agent">Section&nbsp;7.10</a>
     3347                  <td class="left"> <a href="#header.user-agent" id="rfc.xref.header.user-agent.2" title="User-Agent">Section&nbsp;7.18</a>
    30393348                  </td>
    30403349               </tr>
    … …  
    30713380         of From and Referer information.
    30723381      </p>
    3073       <p id="rfc.section.9.1.p.7">The User-Agent (<a href="#header.user-agent" id="rfc.xref.header.user-agent.3" title="User-Agent">Section&nbsp;7.10</a>) or Server (<a href="#header.server" id="rfc.xref.header.server.3" title="Server">Section&nbsp;7.9</a>) header fields can sometimes be used to determine that a specific client or server has a particular security hole which might
     3382      <p id="rfc.section.9.1.p.7">The User-Agent (<a href="#header.user-agent" id="rfc.xref.header.user-agent.3" title="User-Agent">Section&nbsp;7.18</a>) or Server (<a href="#header.server" id="rfc.xref.header.server.3" title="Server">Section&nbsp;7.17</a>) header fields can sometimes be used to determine that a specific client or server has a particular security hole which might
    30743383         be exploited. Unfortunately, this same information is often used for other valuable purposes for which HTTP currently has
    30753384         no better mechanism.
    … …  
    31073416      </p>
    31083417      <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a id="acks" href="#acks">Acknowledgments</a></h1>
    3109       <p id="rfc.section.10.p.1">See <a href="p1-messaging.html#acks" title="Acknowledgments">Section 9</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>.
     3418      <p id="rfc.section.10.p.1">See <a href="p1-messaging.html#acks" title="Acknowledgments">Section 9</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>.
    31103419      </p>
    31113420      <h1 id="rfc.references"><a id="rfc.section.11" href="#rfc.section.11">11.</a> References
    … …  
    33373646      </p>
    33383647      <p id="rfc.section.A.p.11">Reclassify "Allow" as response header field, removing the option to specify it in a PUT request. Relax the server requirement
    3339          on the contents of the Allow header field and remove requirement on clients to always trust the header field value. (<a href="#header.allow" id="rfc.xref.header.allow.4" title="Allow">Section&nbsp;7.1</a>)
     3648         on the contents of the Allow header field and remove requirement on clients to always trust the header field value. (<a href="#header.allow" id="rfc.xref.header.allow.4" title="Allow">Section&nbsp;7.5</a>)
    33403649      </p>
    33413650      <p id="rfc.section.A.p.12">The ABNF for the Expect header field has been both fixed (allowing parameters for value-less expectations as well) and simplified
    3342          (allowing trailing semicolons after "100-continue" when they were invalid before). (<a href="#header.expect" id="rfc.xref.header.expect.4" title="Expect">Section&nbsp;7.3</a>)
     3651         (allowing trailing semicolons after "100-continue" when they were invalid before). (<a href="#header.expect" id="rfc.xref.header.expect.4" title="Expect">Section&nbsp;7.11</a>)
    33433652      </p>
    33443653      <p id="rfc.section.A.p.13">Correct syntax of Location header field to allow URI references (including relative references and fragments), as referred
    33453654         symbol "absoluteURI" wasn't what was expected, and add some clarifications as to when use of fragments would not be appropriate.
    3346          (<a href="#header.location" id="rfc.xref.header.location.5" title="Location">Section&nbsp;7.5</a>)
    3347       </p>
    3348       <p id="rfc.section.A.p.14">Restrict Max-Forwards header field to OPTIONS and TRACE (previously, extension methods could have used it as well). (<a href="#header.max-forwards" id="rfc.xref.header.max-forwards.5" title="Max-Forwards">Section&nbsp;7.6</a>)
    3349       </p>
    3350       <p id="rfc.section.A.p.15">Allow Referer field value of "about:blank" as alternative to not specifying it. (<a href="#header.referer" id="rfc.xref.header.referer.3" title="Referer">Section&nbsp;7.7</a>)
     3655         (<a href="#header.location" id="rfc.xref.header.location.5" title="Location">Section&nbsp;7.13</a>)
     3656      </p>
     3657      <p id="rfc.section.A.p.14">Restrict Max-Forwards header field to OPTIONS and TRACE (previously, extension methods could have used it as well). (<a href="#header.max-forwards" id="rfc.xref.header.max-forwards.5" title="Max-Forwards">Section&nbsp;7.14</a>)
     3658      </p>
     3659      <p id="rfc.section.A.p.15">Allow Referer field value of "about:blank" as alternative to not specifying it. (<a href="#header.referer" id="rfc.xref.header.referer.3" title="Referer">Section&nbsp;7.15</a>)
    33513660      </p>
    33523661      <p id="rfc.section.A.p.16">In the description of the Server header field, the Via field was described as a SHOULD. The requirement was and is stated
    3353          correctly in the description of the Via header field in <a href="p1-messaging.html#header.via" title="Via">Section 6.2</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>. (<a href="#header.server" id="rfc.xref.header.server.4" title="Server">Section&nbsp;7.9</a>)
     3662         correctly in the description of the Via header field in <a href="p1-messaging.html#header.via" title="Via">Section 6.2</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>. (<a href="#header.server" id="rfc.xref.header.server.4" title="Server">Section&nbsp;7.17</a>)
    33543663      </p>
    33553664      <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a>&nbsp;<a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1>
    3356       <div id="rfc.figure.u.43"></div> <pre class="inline"><a href="#header.accept" class="smpl">Accept</a> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [
     3665      <div id="rfc.figure.u.62"></div> <pre class="inline"><a href="#header.accept" class="smpl">Accept</a> = [ ( "," / ( media-range [ accept-params ] ) ) *( OWS "," [
    33573666 OWS media-range [ accept-params ] ] ) ]
    33583667<a href="#header.accept-charset" class="smpl">Accept-Charset</a> = *( "," OWS ) ( charset / "*" ) [ OWS ";" OWS "q="
    … …  
    35013810
    35023811<a href="#preferred.date.format" class="smpl">year</a> = 4DIGIT
    3503 </pre> <div id="rfc.figure.u.44"></div>
     3812</pre> <div id="rfc.figure.u.63"></div>
    35043813      <p>ABNF diagnostics:</p><pre class="inline">; qvalue UNDEFINED
    35053814; Accept defined but not used
    … …  
    35263835      <h2 id="rfc.section.C.1"><a href="#rfc.section.C.1">C.1</a>&nbsp;Since RFC 2616
    35273836      </h2>
    3528       <p id="rfc.section.C.1.p.1">Extracted relevant partitions from <a href="#RFC2616" id="rfc.xref.RFC2616.3"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
     3837      <p id="rfc.section.C.1.p.1">Extracted relevant partitions from <a href="#RFC2616" id="rfc.xref.RFC2616.4"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
    35293838      </p>
    35303839      <h2 id="rfc.section.C.2"><a href="#rfc.section.C.2">C.2</a>&nbsp;Since draft-ietf-httpbis-p2-semantics-00
    … …  
    38624171         header fields". The following payload header fields are defined by HTTP/1.1:
    38634172      </p>
    3864       <div id="rfc.table.u.4">
     4173      <div id="rfc.table.u.5">
    38654174         <table class="tt full left" cellpadding="3" cellspacing="0">
    38664175            <thead>
    … …  
    38734182               <tr>
    38744183                  <td class="left">Content-Length</td>
    3875                   <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>
     4184                  <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.Part1.53"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a></td>
    38764185               </tr>
    38774186               <tr>
    … …  
    38834192      </div>
    38844193      <h3 id="rfc.section.D.1.2"><a href="#rfc.section.D.1.2">D.1.2</a>&nbsp;<a id="payload.body" href="#payload.body">Payload Body</a></h3>
    3885       <p id="rfc.section.D.1.2.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
     4194      <p id="rfc.section.D.1.2.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.Part1.54"><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
    38864195         safe and proper transfer of the message.
    38874196      </p>
    … …  
    39074216      </p>
    39084217      <p id="rfc.section.D.2.1.p.2">The following header fields are defined as representation metadata:</p>
    3909       <div id="rfc.table.u.5">
     4218      <div id="rfc.table.u.6">
    39104219         <table class="tt full left" cellpadding="3" cellspacing="0">
    39114220            <thead>
    … …  
    39184227               <tr>
    39194228                  <td class="left">Content-Encoding</td>
    3920                   <td class="left"><a href="#header.content-encoding" id="rfc.xref.header.content-encoding.3" title="Content-Encoding">Appendix&nbsp;D.4.5</a></td>
     4229                  <td class="left"><a href="#header.content-encoding" id="rfc.xref.header.content-encoding.4" title="Content-Encoding">Section&nbsp;7.6</a></td>
    39214230               </tr>
    39224231               <tr>
    39234232                  <td class="left">Content-Language</td>
    3924                   <td class="left"><a href="#header.content-language" id="rfc.xref.header.content-language.2" title="Content-Language">Appendix&nbsp;D.4.6</a></td>
     4233                  <td class="left"><a href="#header.content-language" id="rfc.xref.header.content-language.2" title="Content-Language">Section&nbsp;7.7</a></td>
    39254234               </tr>
    39264235               <tr>
    39274236                  <td class="left">Content-Location</td>
    3928                   <td class="left"><a href="#header.content-location" id="rfc.xref.header.content-location.4" title="Content-Location">Appendix&nbsp;D.4.7</a></td>
     4237                  <td class="left"><a href="#header.content-location" id="rfc.xref.header.content-location.4" title="Content-Location">Section&nbsp;7.8</a></td>
    39294238               </tr>
    39304239               <tr>
    39314240                  <td class="left">Content-Type</td>
    3932                   <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.5" title="Content-Type">Appendix&nbsp;D.4.8</a></td>
     4241                  <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.5" title="Content-Type">Section&nbsp;7.9</a></td>
    39334242               </tr>
    39344243               <tr>
    … …  
    39434252         metadata:
    39444253      </p>
    3945       <div id="rfc.table.u.6">
     4254      <div id="rfc.table.u.7">
    39464255         <table class="tt full left" cellpadding="3" cellspacing="0">
    39474256            <thead>
    … …  
    39714280         a two-layer, ordered encoding model:
    39724281      </p>
    3973       <div id="rfc.figure.u.45"></div><pre class="text">  representation-data := Content-Encoding( Content-Type( bits ) )
     4282      <div id="rfc.figure.u.64"></div><pre class="text">  representation-data := Content-Encoding( Content-Type( bits ) )
    39744283</pre><p id="rfc.section.D.2.2.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
    39754284         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
    … …  
    40394348         that doesn't conform to them is better than sending a 406 (Not Acceptable) response.
    40404349      </p>
    4041       <p id="rfc.section.D.3.1.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.
     4350      <p id="rfc.section.D.3.1.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.Part1.55"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for more information.
    40424351      </p>
    40434352      <p id="rfc.section.D.3.1.p.6">HTTP/1.1 includes the following header fields for enabling server-driven negotiation through description of user agent capabilities
    4044          and user preferences: Accept (<a href="#header.accept" id="rfc.xref.header.accept.4" title="Accept">Appendix&nbsp;D.4.1</a>), Accept-Charset (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Appendix&nbsp;D.4.2</a>), Accept-Encoding (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.4" title="Accept-Encoding">Appendix&nbsp;D.4.3</a>), Accept-Language (<a href="#header.accept-language" id="rfc.xref.header.accept-language.3" title="Accept-Language">Appendix&nbsp;D.4.4</a>), and User-Agent (<a href="#header.user-agent" id="rfc.xref.header.user-agent.4" title="User-Agent">Section&nbsp;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
     4353         and user preferences: Accept (<a href="#header.accept" id="rfc.xref.header.accept.4" title="Accept">Section&nbsp;7.1</a>), Accept-Charset (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Section&nbsp;7.2</a>), Accept-Encoding (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.4" title="Accept-Encoding">Section&nbsp;7.3</a>), Accept-Language (<a href="#header.accept-language" id="rfc.xref.header.accept-language.3" title="Accept-Language">Section&nbsp;7.4</a>), and User-Agent (<a href="#header.user-agent" id="rfc.xref.header.user-agent.4" title="User-Agent">Section&nbsp;7.18</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
    40454354         within extension header fields not defined by this specification.
    40464355      </p>
    … …  
    40704379         when the server is unwilling or unable to provide a varying response using server-driven negotiation.
    40714380      </p>
    4072       <h2 id="rfc.section.D.4"><a href="#rfc.section.D.4">D.4</a>&nbsp;<a id="header.field.definitions3" href="#header.field.definitions3">Header Field Definitions</a></h2>
    4073       <p id="rfc.section.D.4.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to the payload of messages.</p>
    4074       <div id="rfc.iref.a.2"></div>
    4075       <div id="rfc.iref.h.12"></div>
    4076       <h3 id="rfc.section.D.4.1"><a href="#rfc.section.D.4.1">D.4.1</a>&nbsp;<a id="header.accept" href="#header.accept">Accept</a></h3>
    4077       <p id="rfc.section.D.4.1.p.1">The "Accept" header field can be used by user agents to specify response media types that are acceptable. Accept header fields
    4078          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
    4079          for an in-line image.
    4080       </p>
    4081       <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> ] )
    4082  
    4083   <a href="#header.accept" class="smpl">media-range</a>    = ( "*/*"
    4084                    / ( <a href="#media.types" class="smpl">type</a> "/" "*" )
    4085                    / ( <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> )
    4086                    ) *( <a href="#core.rules" class="smpl">OWS</a> ";" <a href="#core.rules" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> )
    4087   <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> )
    4088   <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> ]
    4089 </pre><p id="rfc.section.D.4.1.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating
    4090          all subtypes of that type. The media-range <em class="bcp14">MAY</em> include media type parameters that are applicable to that range.
    4091       </p>
    4092       <p id="rfc.section.D.4.1.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
    4093          "q" parameter (if any) separates the media-range parameter(s) from the accept-params. Quality factors allow the user or user
    4094          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.
    4095       </p>
    4096       <div class="note" id="rfc.section.D.4.1.p.5">
    4097          <p> <b>Note:</b> Use of the "q" parameter name to separate media type parameters from Accept extension parameters is due to historical practice.
    4098             Although this prevents any media type parameter named "q" from being used with a media range, such an event is believed to
    4099             be unlikely given the lack of any "q" parameters in the IANA media type registry and the rare usage of any media type parameters
    4100             in Accept. Future media types are discouraged from registering any parameter named "q".
    4101          </p>
    4102       </div>
    4103       <p id="rfc.section.D.4.1.p.6">The example</p>
    4104       <div id="rfc.figure.u.47"></div><pre class="text">  Accept: audio/*; q=0.2, audio/basic
    4105 </pre><p id="rfc.section.D.4.1.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
    4106          quality".
    4107       </p>
    4108       <p id="rfc.section.D.4.1.p.9">A request without any Accept header field implies that the user agent will accept any media type in response. If an Accept
    4109          header field is present in a request and none of the available representations for the response have a media type that is
    4110          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
    4111          the response as if it is not subject to content negotiation.
    4112       </p>
    4113       <p id="rfc.section.D.4.1.p.10">A more elaborate example is</p>
    4114       <div id="rfc.figure.u.48"></div><pre class="text">  Accept: text/plain; q=0.5, text/html,
    4115           text/x-dvi; q=0.8, text/x-c
    4116 </pre><p id="rfc.section.D.4.1.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
    4117          send the text/x-dvi representation, and if that does not exist, send the text/plain representation".
    4118       </p>
    4119       <p id="rfc.section.D.4.1.p.13">Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies
    4120          to a given type, the most specific reference has precedence. For example,
    4121       </p>
    4122       <div id="rfc.figure.u.49"></div><pre class="text">  Accept: text/*, text/plain, text/plain;format=flowed, */*
    4123 </pre><p id="rfc.section.D.4.1.p.15">have the following precedence: </p>
    4124       <ol>
    4125          <li>text/plain;format=flowed</li>
    4126          <li>text/plain</li>
    4127          <li>text/*</li>
    4128          <li>*/*</li>
    4129       </ol>
    4130       <p id="rfc.section.D.4.1.p.16">The media type quality factor associated with a given type is determined by finding the media range with the highest precedence
    4131          which matches that type. For example,
    4132       </p>
    4133       <div id="rfc.figure.u.50"></div><pre class="text">  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
    4134           text/html;level=2;q=0.4, */*;q=0.5
    4135 </pre><p id="rfc.section.D.4.1.p.18">would cause the following values to be associated:</p>
    4136       <div id="rfc.table.u.7">
    4137          <table class="tt full left" cellpadding="3" cellspacing="0">
    4138             <thead>
    4139                <tr>
    4140                   <th>Media Type</th>
    4141                   <th>Quality Value</th>
    4142                </tr>
    4143             </thead>
    4144             <tbody>
    4145                <tr>
    4146                   <td class="left">text/html;level=1</td>
    4147                   <td class="left">1</td>
    4148                </tr>
    4149                <tr>
    4150                   <td class="left">text/html</td>
    4151                   <td class="left">0.7</td>
    4152                </tr>
    4153                <tr>
    4154                   <td class="left">text/plain</td>
    4155                   <td class="left">0.3</td>
    4156                </tr>
    4157                <tr>
    4158                   <td class="left">image/jpeg</td>
    4159                   <td class="left">0.5</td>
    4160                </tr>
    4161                <tr>
    4162                   <td class="left">text/html;level=2</td>
    4163                   <td class="left">0.4</td>
    4164                </tr>
    4165                <tr>
    4166                   <td class="left">text/html;level=3</td>
    4167                   <td class="left">0.7</td>
    4168                </tr>
    4169             </tbody>
    4170          </table>
    4171       </div>
    4172       <p id="rfc.section.D.4.1.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
    4173          is a closed system which cannot interact with other rendering agents, this default set ought to be configurable by the user.
    4174       </p>
    4175       <div id="rfc.iref.a.3"></div>
    4176       <div id="rfc.iref.h.13"></div>
    4177       <h3 id="rfc.section.D.4.2"><a href="#rfc.section.D.4.2">D.4.2</a>&nbsp;<a id="header.accept-charset" href="#header.accept-charset">Accept-Charset</a></h3>
    4178       <p id="rfc.section.D.4.2.p.1">The "Accept-Charset" header field can be used by user agents to indicate what character encodings are acceptable in a response
    4179          payload. This field allows clients capable of understanding more comprehensive or special-purpose character encodings to signal
    4180          that capability to a server which is capable of representing documents in those character encodings.
    4181       </p>
    4182       <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> / "*" )
    4183                          [ <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> ] )
    4184 </pre><p id="rfc.section.D.4.2.p.3">Character encoding values (a.k.a., charsets) are described in <a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;6.3</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
    4185          example is
    4186       </p>
    4187       <div id="rfc.figure.u.52"></div><pre class="text">  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
    4188 </pre><p id="rfc.section.D.4.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere
    4189          in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then all character encodings not explicitly
    4190          mentioned get a quality value of 0.
    4191       </p>
    4192       <p id="rfc.section.D.4.2.p.6">A request without any Accept-Charset header field implies that the user agent will accept any character encoding in response.
    4193          If an Accept-Charset header field is present in a request and none of the available representations for the response have
    4194          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
    4195          field by treating the response as if it is not subject to content negotiation.
    4196       </p>
    4197       <div id="rfc.iref.a.4"></div>
    4198       <div id="rfc.iref.h.14"></div>
    4199       <h3 id="rfc.section.D.4.3"><a href="#rfc.section.D.4.3">D.4.3</a>&nbsp;<a id="header.accept-encoding" href="#header.accept-encoding">Accept-Encoding</a></h3>
    4200       <p id="rfc.section.D.4.3.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">Section&nbsp;6.4</a>) are acceptable in the response. An "identity" token is used as a synonym for "no encoding" in order to communicate when
    4201          no encoding is preferred.
    4202       </p>
    4203       <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> ] )
    4204   <a href="#header.accept-encoding" class="smpl">codings</a>          = <a href="#content.codings" class="smpl">content-coding</a> / "identity" / "*"
    4205 </pre><p id="rfc.section.D.4.3.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.
    4206       </p>
    4207       <p id="rfc.section.D.4.3.p.4">For example,</p>
    4208       <div id="rfc.figure.u.54"></div><pre class="text">  Accept-Encoding: compress, gzip
    4209   Accept-Encoding:
    4210   Accept-Encoding: *
    4211   Accept-Encoding: compress;q=0.5, gzip;q=1.0
    4212   Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
    4213 </pre><p id="rfc.section.D.4.3.p.6">A server tests whether a content-coding for a given representation is acceptable, according to an Accept-Encoding field, using
    4214          these rules:
    4215       </p>
    4216       <ol>
    4217          <li>The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed in the header
    4218             field.
    4219          </li>
    4220          <li>If the representation has no content-coding, then it is acceptable by default unless specifically excluded by the Accept-Encoding
    4221             field stating either "identity;q=0" or "*;q=0" without a more specific entry for "identity".
    4222          </li>
    4223          <li>If the representation's content-coding is one of the content-codings listed in the Accept-Encoding field, then it is acceptable
    4224             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".)
    4225          </li>
    4226          <li>If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero qvalue is preferred.</li>
    4227       </ol>
    4228       <p id="rfc.section.D.4.3.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
    4229          in response. If an Accept-Encoding header field is present in a request and none of the available representations for the
    4230          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.
    4231       </p>
    4232       <p id="rfc.section.D.4.3.p.8">A request without an Accept-Encoding header field implies that the user agent will accept any content-coding in response,
    4233          but a representation without content-coding is preferred for compatibility with the widest variety of user agents.
    4234       </p>
    4235       <div class="note" id="rfc.section.D.4.3.p.9">
    4236          <p> <b>Note:</b> Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. This means that qvalues will
    4237             not work and are not permitted with x-gzip or x-compress.
    4238          </p>
    4239       </div>
    4240       <div id="rfc.iref.a.5"></div>
    4241       <div id="rfc.iref.h.15"></div>
    4242       <h3 id="rfc.section.D.4.4"><a href="#rfc.section.D.4.4">D.4.4</a>&nbsp;<a id="header.accept-language" href="#header.accept-language">Accept-Language</a></h3>
    4243       <p id="rfc.section.D.4.4.p.1">The "Accept-Language" header field can be used by user agents to indicate the set of natural languages that are preferred
    4244          in the response. Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;6.6</a>.
    4245       </p>
    4246       <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> =
    4247                     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> ] )
    4248   <a href="#header.accept-language" class="smpl">language-range</a>  =
    4249             &lt;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>&gt;
    4250 </pre><p id="rfc.section.D.4.4.p.3">Each language-range can be given an associated quality value which represents an estimate of the user's preference for the
    4251          languages specified by that range. The quality value defaults to "q=1". For example,
    4252       </p>
    4253       <div id="rfc.figure.u.56"></div><pre class="text">  Accept-Language: da, en-gb;q=0.8, en;q=0.7
    4254 </pre><p id="rfc.section.D.4.4.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>)
    4255       </p>
    4256       <p id="rfc.section.D.4.4.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.
    4257       </p>
    4258       <div class="note" id="rfc.section.D.4.4.p.7">
    4259          <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>.
    4260          </p>
    4261       </div>
    4262       <p id="rfc.section.D.4.4.p.8">It might be contrary to the privacy expectations of the user to send an Accept-Language header field with the complete linguistic
    4263          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&nbsp;D.6.1</a>.
    4264       </p>
    4265       <p id="rfc.section.D.4.4.p.9">As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice
    4266          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.
    4267       </p>
    4268       <div class="note" id="rfc.section.D.4.4.p.10">
    4269          <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
    4270             familiar with the details of language matching as described above, and ought to be provided appropriate guidance. As an example,
    4271             users might assume that on selecting "en-gb", they will be served any kind of English document if British English is not available.
    4272             A user agent might suggest in such a case to add "en" to get the best matching behavior.
    4273          </p>
    4274       </div>
    4275       <div id="rfc.iref.c.7"></div>
    4276       <div id="rfc.iref.h.16"></div>
    4277       <h3 id="rfc.section.D.4.5"><a href="#rfc.section.D.4.5">D.4.5</a>&nbsp;<a id="header.content-encoding" href="#header.content-encoding">Content-Encoding</a></h3>
    4278       <p id="rfc.section.D.4.5.p.1">The "Content-Encoding" header field indicates what content-codings have been applied to the representation beyond those inherent
    4279          in the media type, and thus what decoding mechanisms have to be applied in order to obtain the media-type referenced by the
    4280          Content-Type header field. Content-Encoding is primarily used to allow a representation to be compressed without losing the
    4281          identity of its underlying media type.
    4282       </p>
    4283       <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>
    4284 </pre><p id="rfc.section.D.4.5.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section&nbsp;6.4</a>. An example of its use is
    4285       </p>
    4286       <div id="rfc.figure.u.58"></div><pre class="text">  Content-Encoding: gzip
    4287 </pre><p id="rfc.section.D.4.5.p.5">The content-coding is a characteristic of the representation. Typically, the representation body is stored with this encoding
    4288          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
    4289          directive is present in the message.
    4290       </p>
    4291       <p id="rfc.section.D.4.5.p.6">If the media type includes an inherent encoding, such as a data format that is always compressed, then that encoding would
    4292          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
    4293          would only be listed if, for some bizarre reason, it is applied a second time to form the representation. Likewise, an origin
    4294          server might choose to publish the same payload data as multiple representations that differ only in whether the coding is
    4295          defined as part of Content-Type or Content-Encoding, since some user agents will behave differently in their handling of each
    4296          response (e.g., open a "Save as ..." dialog instead of automatic decompression and rendering of content).
    4297       </p>
    4298       <p id="rfc.section.D.4.5.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&nbsp;D.4.5</a>) that lists the content-coding(s) applied.
    4299       </p>
    4300       <p id="rfc.section.D.4.5.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.
    4301       </p>
    4302       <p id="rfc.section.D.4.5.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).
    4303       </p>
    4304       <div id="rfc.iref.c.8"></div>
    4305       <div id="rfc.iref.h.17"></div>
    4306       <h3 id="rfc.section.D.4.6"><a href="#rfc.section.D.4.6">D.4.6</a>&nbsp;<a id="header.content-language" href="#header.content-language">Content-Language</a></h3>
    4307       <p id="rfc.section.D.4.6.p.1">The "Content-Language" header field describes the natural language(s) of the intended audience for the representation. Note
    4308          that this might not be equivalent to all the languages used within the representation.
    4309       </p>
    4310       <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>
    4311 </pre><p id="rfc.section.D.4.6.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section&nbsp;6.6</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the
    4312          user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate
    4313          field is
    4314       </p>
    4315       <div id="rfc.figure.u.60"></div><pre class="text">  Content-Language: da
    4316 </pre><p id="rfc.section.D.4.6.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean
    4317          that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language
    4318          it is intended.
    4319       </p>
    4320       <p id="rfc.section.D.4.6.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
    4321          simultaneously in the original Maori and English versions, would call for
    4322       </p>
    4323       <div id="rfc.figure.u.61"></div><pre class="text">  Content-Language: mi, en
    4324 </pre><p id="rfc.section.D.4.6.p.8">However, just because multiple languages are present within a representation does not mean that it is intended for multiple
    4325          linguistic audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin", which is clearly
    4326          intended to be used by an English-literate audience. In this case, the Content-Language would properly only include "en".
    4327       </p>
    4328       <p id="rfc.section.D.4.6.p.9">Content-Language <em class="bcp14">MAY</em> be applied to any media type — it is not limited to textual documents.
    4329       </p>
    4330       <div id="rfc.iref.c.9"></div>
    4331       <div id="rfc.iref.h.18"></div>
    4332       <h3 id="rfc.section.D.4.7"><a href="#rfc.section.D.4.7">D.4.7</a>&nbsp;<a id="header.content-location" href="#header.content-location">Content-Location</a></h3>
    4333       <p id="rfc.section.D.4.7.p.1">The "Content-Location" header field supplies a URI that can be used as a specific identifier for the representation in this
    4334          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
    4335          would contain the same representation that is enclosed as payload in this message.
    4336       </p>
    4337       <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>
    4338 </pre><p id="rfc.section.D.4.7.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
    4339          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.
    4340       </p>
    4341       <p id="rfc.section.D.4.7.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
    4342          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
    4343          when no Content-Location is provided by the server. For a state-changing request like PUT or POST, it implies that the server's
    4344          response contains the new representation of that resource, thereby distinguishing it from representations that might only
    4345          report about the action (e.g., "It worked!"). This allows authoring applications to update their local copies without the
    4346          need for a subsequent GET request.
    4347       </p>
    4348       <p id="rfc.section.D.4.7.p.5">If Content-Location is included in a response message and its value differs from the effective request URI, then the origin
    4349          server is informing recipients that this representation has its own, presumably more specific, identifier. For a GET or HEAD
    4350          request, this is an indication that the effective request URI identifies a resource that is subject to content negotiation
    4351          and the selected representation for this response can also be found at the identified URI. For other methods, such a Content-Location
    4352          indicates that this representation contains a report on the action's status and the same report is available (for future access
    4353          with GET) at the given URI. For example, a purchase transaction made via a POST request might include a receipt document as
    4354          the payload of the 200 response; the Content-Location value provides an identifier for retrieving a copy of that same receipt
    4355          in the future.
    4356       </p>
    4357       <p id="rfc.section.D.4.7.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
    4358          representation (prior to any subsequent modification of the content by that user agent). In other words, the user agent is
    4359          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
    4360          resource and the origin server accepts that PUT (without redirection), then the new set of values for that resource is expected
    4361          to be consistent with the one representation supplied in that PUT; the Content-Location cannot be used as a form of reverse
    4362          content selection that identifies only one of the negotiated representations to be updated. If the user agent had wanted the
    4363          latter semantics, it would have applied the PUT directly to the Content-Location URI.
    4364       </p>
    4365       <p id="rfc.section.D.4.7.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
    4366          in other contexts, such as within source links or other metadata.
    4367       </p>
    4368       <p id="rfc.section.D.4.7.p.8">A cache cannot assume that a representation with a Content-Location different from the URI used to retrieve it can be used
    4369          to respond to later requests on that Content-Location URI.
    4370       </p>
    4371       <p id="rfc.section.D.4.7.p.9">If the Content-Location value is a partial URI, the partial URI is interpreted relative to the effective request URI.</p>
    4372       <div id="rfc.iref.c.10"></div>
    4373       <div id="rfc.iref.h.19"></div>
    4374       <h3 id="rfc.section.D.4.8"><a href="#rfc.section.D.4.8">D.4.8</a>&nbsp;<a id="header.content-type" href="#header.content-type">Content-Type</a></h3>
    4375       <p id="rfc.section.D.4.8.p.1">The "Content-Type" header field indicates the media type of the representation. In the case of responses to the HEAD method,
    4376          the media type is that which would have been sent had the request been a GET.
    4377       </p>
    4378       <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>
    4379 </pre><p id="rfc.section.D.4.8.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section&nbsp;6.5</a>. An example of the field is
    4380       </p>
    4381       <div id="rfc.figure.u.64"></div><pre class="text">  Content-Type: text/html; charset=ISO-8859-4
    4382 </pre><p id="rfc.section.D.4.8.p.5">Further discussion of Content-Type is provided in <a href="#representation.data" title="Representation Data">Appendix&nbsp;D.2.2</a>.
    4383       </p>
    4384       <h2 id="rfc.section.D.5"><a href="#rfc.section.D.5">D.5</a>&nbsp;<a id="IANA.considerations3" href="#IANA.considerations3">IANA Considerations</a></h2>
    4385       <h3 id="rfc.section.D.5.1"><a href="#rfc.section.D.5.1">D.5.1</a>&nbsp;<a id="content.coding.registration" href="#content.coding.registration">Content Coding Registry</a></h3>
    4386       <p id="rfc.section.D.5.1.p.1">The registration procedure for HTTP Content Codings is now defined by <a href="#content.coding.registry" title="Content Coding Registry">Section&nbsp;6.4.1</a> of this document.
    4387       </p>
    4388       <p id="rfc.section.D.5.1.p.2">The HTTP Content Codings Registry located at &lt;<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>&gt; shall be updated with the registration below:
     4381      <h2 id="rfc.section.D.4"><a href="#rfc.section.D.4">D.4</a>&nbsp;<a id="IANA.considerations3" href="#IANA.considerations3">IANA Considerations</a></h2>
     4382      <h3 id="rfc.section.D.4.1"><a href="#rfc.section.D.4.1">D.4.1</a>&nbsp;<a id="content.coding.registration" href="#content.coding.registration">Content Coding Registry</a></h3>
     4383      <p id="rfc.section.D.4.1.p.1">The registration procedure for HTTP Content Codings is now defined by <a href="#content.coding.registry" title="Content Coding Registry">Section&nbsp;6.4.1</a> of this document.
     4384      </p>
     4385      <p id="rfc.section.D.4.1.p.2">The HTTP Content Codings Registry located at &lt;<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>&gt; shall be updated with the registration below:
    43894386      </p>
    43904387      <div id="rfc.table.4">
    … …  
    44214418                  <td class="left">identity</td>
    44224419                  <td class="left">reserved (synonym for "no encoding" in Accept-Encoding header field)</td>
    4423                   <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.5" title="Accept-Encoding">Appendix&nbsp;D.4.3</a>
     4420                  <td class="left"> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.5" title="Accept-Encoding">Section&nbsp;7.3</a>
    44244421                  </td>
    44254422               </tr>
    … …  
    44274424         </table>
    44284425      </div>
    4429       <h2 id="rfc.section.D.6"><a href="#rfc.section.D.6">D.6</a>&nbsp;<a id="security.considerations3" href="#security.considerations3">Security Considerations</a></h2>
    4430       <p id="rfc.section.D.6.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
     4426      <h2 id="rfc.section.D.5"><a href="#rfc.section.D.5">D.5</a>&nbsp;<a id="security.considerations3" href="#security.considerations3">Security Considerations</a></h2>
     4427      <p id="rfc.section.D.5.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1
    44314428         as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does
    44324429         make some suggestions for reducing security risks.
    44334430      </p>
    4434       <h3 id="rfc.section.D.6.1"><a href="#rfc.section.D.6.1">D.6.1</a>&nbsp;<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>
    4435       <p id="rfc.section.D.6.1.p.1">Accept header fields can reveal information about the user to all servers which are accessed. The Accept-Language header field
     4431      <h3 id="rfc.section.D.5.1"><a href="#rfc.section.D.5.1">D.5.1</a>&nbsp;<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>
     4432      <p id="rfc.section.D.5.1.p.1">Accept header fields can reveal information about the user to all servers which are accessed. The Accept-Language header field
    44364433         in particular can reveal information the user would consider to be of a private nature, because the understanding of particular
    44374434         languages is often strongly correlated to the membership of a particular ethnic group. User agents which offer the option
    … …  
    44394436         configuration process include a message which makes the user aware of the loss of privacy involved.
    44404437      </p>
    4441       <p id="rfc.section.D.6.1.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
     4438      <p id="rfc.section.D.5.1.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
    44424439         by default, and to ask the user whether or not to start sending Accept-Language header fields to a server if it detects, by
    44434440         looking for any Vary header fields generated by the server, that such sending could improve the quality of service.
    44444441      </p>
    4445       <p id="rfc.section.D.6.1.p.3">Elaborate user-customized accept header fields sent in every request, in particular if these include quality values, can be
     4442      <p id="rfc.section.D.5.1.p.3">Elaborate user-customized accept header fields sent in every request, in particular if these include quality values, can be
    44464443         used by servers as relatively reliable and long-lived user identifiers. Such user identifiers would allow content providers
    44474444         to do click-trail tracking, and would allow collaborating content providers to match cross-server click-trails or form submissions
    … …  
    44514448         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.
    44524449      </p>
    4453       <h2 id="rfc.section.D.7"><a href="#rfc.section.D.7">D.7</a>&nbsp;<a id="differences.between.http.and.mime" href="#differences.between.http.and.mime">Differences between HTTP and MIME</a></h2>
    4454       <p id="rfc.section.D.7.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,
     4450      <h2 id="rfc.section.D.6"><a href="#rfc.section.D.6">D.6</a>&nbsp;<a id="differences.between.http.and.mime" href="#differences.between.http.and.mime">Differences between HTTP and MIME</a></h2>
     4451      <p id="rfc.section.D.6.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,
    44554452         RFC 2045 discusses mail, and HTTP has a few features that are different from those described in MIME. These differences were
    44564453         carefully chosen to optimize performance over binary connections, to allow greater freedom in the use of new media types,
    44574454         to make date comparisons easier, and to acknowledge the practice of some early HTTP servers and clients.
    44584455      </p>
    4459       <p id="rfc.section.D.7.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
     4456      <p id="rfc.section.D.6.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
    44604457         to HTTP also need to be aware of the differences because some conversions might be required.
    44614458      </p>
    44624459      <div id="rfc.iref.m.10"></div>
    44634460      <div id="rfc.iref.h.20"></div>
    4464       <h3 id="rfc.section.D.7.1"><a href="#rfc.section.D.7.1">D.7.1</a>&nbsp;<a id="mime-version" href="#mime-version">MIME-Version</a></h3>
    4465       <p id="rfc.section.D.7.1.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.
     4461      <h3 id="rfc.section.D.6.1"><a href="#rfc.section.D.6.1">D.6.1</a>&nbsp;<a id="mime-version" href="#mime-version">MIME-Version</a></h3>
     4462      <p id="rfc.section.D.6.1.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.
    44664463         Use of the MIME-Version header field indicates that the message is in full conformance with the MIME protocol (as defined
    44674464         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
    … …  
    44694466      </p>
    44704467      <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>
    4471 </pre><p id="rfc.section.D.7.1.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
     4468</pre><p id="rfc.section.D.6.1.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
    44724469         document and not the MIME specification.
    44734470      </p>
    4474       <h3 id="rfc.section.D.7.2"><a href="#rfc.section.D.7.2">D.7.2</a>&nbsp;<a id="conversion.to.canonical.form" href="#conversion.to.canonical.form">Conversion to Canonical Form</a></h3>
    4475       <p id="rfc.section.D.7.2.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">Section&nbsp;6.5.1</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
     4471      <h3 id="rfc.section.D.6.2"><a href="#rfc.section.D.6.2">D.6.2</a>&nbsp;<a id="conversion.to.canonical.form" href="#conversion.to.canonical.form">Conversion to Canonical Form</a></h3>
     4472      <p id="rfc.section.D.6.2.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">Section&nbsp;6.5.1</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
    44764473         break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a line break within text content when a message is transmitted
    44774474         over HTTP.
    44784475      </p>
    4479       <p id="rfc.section.D.7.2.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">Section&nbsp;6.5.1</a> of this document to the RFC 2049 canonical form of CRLF. Note, however, that this might be complicated by the presence of
     4476      <p id="rfc.section.D.6.2.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">Section&nbsp;6.5.1</a> of this document to the RFC 2049 canonical form of CRLF. Note, however, that this might be complicated by the presence of
    44804477         a Content-Encoding and by the fact that HTTP allows the use of some character encodings which do not use octets 13 and 10
    44814478         to represent CR and LF, respectively, as is the case for some multi-byte character encodings.
    44824479      </p>
    4483       <p id="rfc.section.D.7.2.p.3">Conversion will break any cryptographic checksums applied to the original content unless the original content is already in
     4480      <p id="rfc.section.D.6.2.p.3">Conversion will break any cryptographic checksums applied to the original content unless the original content is already in
    44844481         canonical form. Therefore, the canonical form is recommended for any content that uses such checksums in HTTP.
    44854482      </p>
    4486       <h3 id="rfc.section.D.7.3"><a href="#rfc.section.D.7.3">D.7.3</a>&nbsp;<a id="conversion.of.date.formats" href="#conversion.of.date.formats">Conversion of Date Formats</a></h3>
    4487       <p id="rfc.section.D.7.3.p.1">HTTP/1.1 uses a restricted set of date formats (<a href="#http.date" title="Date/Time Formats">Section&nbsp;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.
    4488       </p>
    4489       <h3 id="rfc.section.D.7.4"><a href="#rfc.section.D.7.4">D.7.4</a>&nbsp;<a id="introduction.of.content-encoding" href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></h3>
    4490       <p id="rfc.section.D.7.4.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
     4483      <h3 id="rfc.section.D.6.3"><a href="#rfc.section.D.6.3">D.6.3</a>&nbsp;<a id="conversion.of.date.formats" href="#conversion.of.date.formats">Conversion of Date Formats</a></h3>
     4484      <p id="rfc.section.D.6.3.p.1">HTTP/1.1 uses a restricted set of date formats (<a href="#http.date" title="Date/Time Formats">Section&nbsp;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.
     4485      </p>
     4486      <h3 id="rfc.section.D.6.4"><a href="#rfc.section.D.6.4">D.6.4</a>&nbsp;<a id="introduction.of.content-encoding" href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></h3>
     4487      <p id="rfc.section.D.6.4.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
    44914488         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
    44924489         experimental applications of Content-Type for Internet mail have used a media-type parameter of ";conversions=&lt;content-coding&gt;"
    … …  
    44954492      <div id="rfc.iref.c.11"></div>
    44964493      <div id="rfc.iref.h.21"></div>
    4497       <h3 id="rfc.section.D.7.5"><a href="#rfc.section.D.7.5">D.7.5</a>&nbsp;<a id="no.content-transfer-encoding" href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></h3>
    4498       <p id="rfc.section.D.7.5.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.
    4499       </p>
    4500       <p id="rfc.section.D.7.5.p.2">Proxies and gateways from HTTP to MIME-compliant protocols are responsible for ensuring that the message is in the correct
     4494      <h3 id="rfc.section.D.6.5"><a href="#rfc.section.D.6.5">D.6.5</a>&nbsp;<a id="no.content-transfer-encoding" href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></h3>
     4495      <p id="rfc.section.D.6.5.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.
     4496      </p>
     4497      <p id="rfc.section.D.6.5.p.2">Proxies and gateways from HTTP to MIME-compliant protocols are responsible for ensuring that the message is in the correct
    45014498         format and encoding for safe transport on that protocol, where "safe transport" is defined by the limitations of the protocol
    45024499         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
    45034500         the destination protocol.
    45044501      </p>
    4505       <h3 id="rfc.section.D.7.6"><a href="#rfc.section.D.7.6">D.7.6</a>&nbsp;<a id="introduction.of.transfer-encoding" href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></h3>
    4506       <p id="rfc.section.D.7.6.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.
    4507       </p>
    4508       <h3 id="rfc.section.D.7.7"><a href="#rfc.section.D.7.7">D.7.7</a>&nbsp;<a id="mhtml.line.length" href="#mhtml.line.length">MHTML and Line Length Limitations</a></h3>
    4509       <p id="rfc.section.D.7.7.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
     4502      <h3 id="rfc.section.D.6.6"><a href="#rfc.section.D.6.6">D.6.6</a>&nbsp;<a id="introduction.of.transfer-encoding" href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></h3>
     4503      <p id="rfc.section.D.6.6.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.
     4504      </p>
     4505      <h3 id="rfc.section.D.6.7"><a href="#rfc.section.D.6.7">D.6.7</a>&nbsp;<a id="mhtml.line.length" href="#mhtml.line.length">MHTML and Line Length Limitations</a></h3>
     4506      <p id="rfc.section.D.6.7.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
    45104507         fold long lines. MHTML messages being transported by HTTP follow all conventions of MHTML, including line length limitations
    45114508         and folding, canonicalization, etc., since HTTP transports all message-bodies as payload (see <a href="#multipart.types" title="Multipart Types">Section&nbsp;6.5.2</a>) and does not interpret the content or any MIME header lines that might be contained therein.
    45124509      </p>
    4513       <h2 id="rfc.section.D.8"><a href="#rfc.section.D.8">D.8</a>&nbsp;<a id="additional.features" href="#additional.features">Additional Features</a></h2>
    4514       <p id="rfc.section.D.8.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
     4510      <h2 id="rfc.section.D.7"><a href="#rfc.section.D.7">D.7</a>&nbsp;<a id="additional.features" href="#additional.features">Additional Features</a></h2>
     4511      <p id="rfc.section.D.7.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
    45154512         applications. Implementors are advised to be aware of these features, but cannot rely upon their presence in, or interoperability
    45164513         with, other HTTP/1.1 applications. Some of these describe proposed experimental features, and some describe features that
    45174514         experimental deployment found lacking that are now addressed in the base HTTP/1.1 specification.
    45184515      </p>
    4519       <p id="rfc.section.D.8.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>).
    4520       </p>
    4521       <h2 id="rfc.section.D.9"><a href="#rfc.section.D.9">D.9</a>&nbsp;<a id="changes.from.rfc.2616-3" href="#changes.from.rfc.2616-3">Changes from RFC 2616</a></h2>
    4522       <p id="rfc.section.D.9.p.1">Clarify contexts that charset is used in. (<a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;6.3</a>)
    4523       </p>
    4524       <p id="rfc.section.D.9.p.2">Registration of Content Codings now requires IETF Review (<a href="#content.coding.registry" title="Content Coding Registry">Section&nbsp;6.4.1</a>)
    4525       </p>
    4526       <p id="rfc.section.D.9.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">Section&nbsp;6.5.1</a>)
    4527       </p>
    4528       <p id="rfc.section.D.9.p.4">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;7</a>)
    4529       </p>
    4530       <p id="rfc.section.D.9.p.5">Remove definition of Content-MD5 header field because it was inconsistently implemented with respect to partial responses,
     4516      <p id="rfc.section.D.7.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>).
     4517      </p>
     4518      <h2 id="rfc.section.D.8"><a href="#rfc.section.D.8">D.8</a>&nbsp;<a id="changes.from.rfc.2616-3" href="#changes.from.rfc.2616-3">Changes from RFC 2616</a></h2>
     4519      <p id="rfc.section.D.8.p.1">Clarify contexts that charset is used in. (<a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;6.3</a>)
     4520      </p>
     4521      <p id="rfc.section.D.8.p.2">Registration of Content Codings now requires IETF Review (<a href="#content.coding.registry" title="Content Coding Registry">Section&nbsp;6.4.1</a>)
     4522      </p>
     4523      <p id="rfc.section.D.8.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">Section&nbsp;6.5.1</a>)
     4524      </p>
     4525      <p id="rfc.section.D.8.p.4">Change ABNF productions for header fields to only define the field value. (<a href="#header.field.definitions" title="Header Field Definitions">Section&nbsp;7</a>)
     4526      </p>
     4527      <p id="rfc.section.D.8.p.5">Remove definition of Content-MD5 header field because it was inconsistently implemented with respect to partial responses,
    45314528         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&nbsp;7</a>)
    45324529      </p>
    4533       <p id="rfc.section.D.9.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&nbsp;D.4.2</a>)
    4534       </p>
    4535       <p id="rfc.section.D.9.p.7">Remove base URI setting semantics for Content-Location due to poor implementation support, which was caused by too many broken
     4530      <p id="rfc.section.D.8.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">Section&nbsp;7.2</a>)
     4531      </p>
     4532      <p id="rfc.section.D.8.p.7">Remove base URI setting semantics for Content-Location due to poor implementation support, which was caused by too many broken
    45364533         servers emitting bogus Content-Location header fields, and also the potentially undesirable effect of potentially breaking
    4537          relative links in content-negotiated resources. (<a href="#header.content-location" id="rfc.xref.header.content-location.5" title="Content-Location">Appendix&nbsp;D.4.7</a>)
    4538       </p>
    4539       <p id="rfc.section.D.9.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&nbsp;D.7.5</a>)
    4540       </p>
    4541       <p id="rfc.section.D.9.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&nbsp;D.8</a>)
    4542       </p>
    4543       <h2 id="rfc.section.D.10"><a href="#rfc.section.D.10">D.10</a>&nbsp;<a id="change.log3" href="#change.log3">Change Log (to be removed by RFC Editor before publication)</a></h2>
    4544       <h3 id="rfc.section.D.10.1"><a href="#rfc.section.D.10.1">D.10.1</a>&nbsp;Since RFC 2616
     4534         relative links in content-negotiated resources. (<a href="#header.content-location" id="rfc.xref.header.content-location.5" title="Content-Location">Section&nbsp;7.8</a>)
     4535      </p>
     4536      <p id="rfc.section.D.8.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&nbsp;D.6.5</a>)
     4537      </p>
     4538      <p id="rfc.section.D.8.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&nbsp;D.7</a>)
     4539      </p>
     4540      <h2 id="rfc.section.D.9"><a href="#rfc.section.D.9">D.9</a>&nbsp;<a id="change.log3" href="#change.log3">Change Log (to be removed by RFC Editor before publication)</a></h2>
     4541      <h3 id="rfc.section.D.9.1"><a href="#rfc.section.D.9.1">D.9.1</a>&nbsp;Since RFC 2616
    45454542      </h3>
    4546       <p id="rfc.section.D.10.1.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>.
    4547       </p>
    4548       <h3 id="rfc.section.D.10.2"><a href="#rfc.section.D.10.2">D.10.2</a>&nbsp;Since draft-ietf-httpbis-p3-payload-00
     4543      <p id="rfc.section.D.9.1.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>.
     4544      </p>
     4545      <h3 id="rfc.section.D.9.2"><a href="#rfc.section.D.9.2">D.9.2</a>&nbsp;Since draft-ietf-httpbis-p3-payload-00
    45494546      </h3>
    4550       <p id="rfc.section.D.10.2.p.1">Closed issues: </p>
     4547      <p id="rfc.section.D.9.2.p.1">Closed issues: </p>
    45514548      <ul>
    45524549         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/8">http://tools.ietf.org/wg/httpbis/trac/ticket/8</a>&gt;: "Media Type Registrations" (&lt;<a href="http://purl.org/NET/http-errata#media-reg">http://purl.org/NET/http-errata#media-reg</a>&gt;)
    … …  
    45734570         </li>
    45744571      </ul>
    4575       <h3 id="rfc.section.D.10.3"><a href="#rfc.section.D.10.3">D.10.3</a>&nbsp;Since draft-ietf-httpbis-p3-payload-01
     4572      <h3 id="rfc.section.D.9.3"><a href="#rfc.section.D.9.3">D.9.3</a>&nbsp;Since draft-ietf-httpbis-p3-payload-01
    45764573      </h3>
    4577       <p id="rfc.section.D.10.3.p.1">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
     4574      <p id="rfc.section.D.9.3.p.1">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
    45784575      </p>
    45794576      <ul>
    45804577         <li>Add explicit references to BNF syntax and rules imported from other parts of the specification.</li>
    45814578      </ul>
    4582       <h3 id="rfc.section.D.10.4"><a href="#rfc.section.D.10.4">D.10.4</a>&nbsp;<a id="changes.3.since.02" href="#changes.3.since.02">Since draft-ietf-httpbis-p3-payload-02</a></h3>
    4583       <p id="rfc.section.D.10.4.p.1">Closed issues: </p>
     4579      <h3 id="rfc.section.D.9.4"><a href="#rfc.section.D.9.4">D.9.4</a>&nbsp;<a id="changes.3.since.02" href="#changes.3.since.02">Since draft-ietf-httpbis-p3-payload-02</a></h3>
     4580      <p id="rfc.section.D.9.4.p.1">Closed issues: </p>
    45844581      <ul>
    45854582         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/67">http://tools.ietf.org/wg/httpbis/trac/ticket/67</a>&gt;: "Quoting Charsets"
    … …  
    45904587         </li>
    45914588      </ul>
    4592       <p id="rfc.section.D.10.4.p.2">Ongoing work on IANA Message Header Field Registration (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/40">http://tools.ietf.org/wg/httpbis/trac/ticket/40</a>&gt;):
     4589      <p id="rfc.section.D.9.4.p.2">Ongoing work on IANA Message Header Field Registration (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/40">http://tools.ietf.org/wg/httpbis/trac/ticket/40</a>&gt;):
    45934590      </p>
    45944591      <ul>
    45954592         <li>Reference RFC 3984, and update header field registrations for headers defined in this document.</li>
    45964593      </ul>
    4597       <h3 id="rfc.section.D.10.5"><a href="#rfc.section.D.10.5">D.10.5</a>&nbsp;<a id="changes.3.since.03" href="#changes.3.since.03">Since draft-ietf-httpbis-p3-payload-03</a></h3>
    4598       <p id="rfc.section.D.10.5.p.1">Closed issues: </p>
     4594      <h3 id="rfc.section.D.9.5"><a href="#rfc.section.D.9.5">D.9.5</a>&nbsp;<a id="changes.3.since.03" href="#changes.3.since.03">Since draft-ietf-httpbis-p3-payload-03</a></h3>
     4595      <p id="rfc.section.D.9.5.p.1">Closed issues: </p>
    45994596      <ul>
    46004597         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/67">http://tools.ietf.org/wg/httpbis/trac/ticket/67</a>&gt;: "Quoting Charsets"
    … …  
    46054602         </li>
    46064603      </ul>
    4607       <p id="rfc.section.D.10.5.p.2">Other changes: </p>
     4604      <p id="rfc.section.D.9.5.p.2">Other changes: </p>
    46084605      <ul>
    46094606         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/68">http://tools.ietf.org/wg/httpbis/trac/ticket/68</a>&gt;: "Encoding References Normative" — rephrase the annotation and reference BCP97.
    46104607         </li>
    46114608      </ul>
    4612       <h3 id="rfc.section.D.10.6"><a href="#rfc.section.D.10.6">D.10.6</a>&nbsp;<a id="changes.3.since.04" href="#changes.3.since.04">Since draft-ietf-httpbis-p3-payload-04</a></h3>
    4613       <p id="rfc.section.D.10.6.p.1">Closed issues: </p>
     4609      <h3 id="rfc.section.D.9.6"><a href="#rfc.section.D.9.6">D.9.6</a>&nbsp;<a id="changes.3.since.04" href="#changes.3.since.04">Since draft-ietf-httpbis-p3-payload-04</a></h3>
     4610      <p id="rfc.section.D.9.6.p.1">Closed issues: </p>
    46144611      <ul>
    46154612         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/132">http://tools.ietf.org/wg/httpbis/trac/ticket/132</a>&gt;: "RFC 2822 is updated by RFC 5322"
    46164613         </li>
    46174614      </ul>
    4618       <p id="rfc.section.D.10.6.p.2">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
     4615      <p id="rfc.section.D.9.6.p.2">Ongoing work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
    46194616      </p>
    46204617      <ul>
    … …  
    46234620         <li>Rewrite ABNFs to spell out whitespace rules, factor out header field value format definitions.</li>
    46244621      </ul>
    4625       <h3 id="rfc.section.D.10.7"><a href="#rfc.section.D.10.7">D.10.7</a>&nbsp;<a id="changes.3.since.05" href="#changes.3.since.05">Since draft-ietf-httpbis-p3-payload-05</a></h3>
    4626       <p id="rfc.section.D.10.7.p.1">Closed issues: </p>
     4622      <h3 id="rfc.section.D.9.7"><a href="#rfc.section.D.9.7">D.9.7</a>&nbsp;<a id="changes.3.since.05" href="#changes.3.since.05">Since draft-ietf-httpbis-p3-payload-05</a></h3>
     4623      <p id="rfc.section.D.9.7.p.1">Closed issues: </p>
    46274624      <ul>
    46284625         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/118">http://tools.ietf.org/wg/httpbis/trac/ticket/118</a>&gt;: "Join "Differences Between HTTP Entities and RFC 2045 Entities"?"
    46294626         </li>
    46304627      </ul>
    4631       <p id="rfc.section.D.10.7.p.2">Final work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
     4628      <p id="rfc.section.D.9.7.p.2">Final work on ABNF conversion (&lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>&gt;):
    46324629      </p>
    46334630      <ul>
    46344631         <li>Add appendix containing collected and expanded ABNF, reorganize ABNF introduction.</li>
    46354632      </ul>
    4636       <p id="rfc.section.D.10.7.p.3">Other changes: </p>
     4633      <p id="rfc.section.D.9.7.p.3">Other changes: </p>
    46374634      <ul>
    46384635         <li>Move definition of quality values into Part 1.</li>
    46394636      </ul>
    4640       <h3 id="rfc.section.D.10.8"><a href="#rfc.section.D.10.8">D.10.8</a>&nbsp;<a id="changes.3.since.06" href="#changes.3.since.06">Since draft-ietf-httpbis-p3-payload-06</a></h3>
    4641       <p id="rfc.section.D.10.8.p.1">Closed issues: </p>
     4637      <h3 id="rfc.section.D.9.8"><a href="#rfc.section.D.9.8">D.9.8</a>&nbsp;<a id="changes.3.since.06" href="#changes.3.since.06">Since draft-ietf-httpbis-p3-payload-06</a></h3>
     4638      <p id="rfc.section.D.9.8.p.1">Closed issues: </p>
    46424639      <ul>
    46434640         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/80">http://tools.ietf.org/wg/httpbis/trac/ticket/80</a>&gt;: "Content-Location isn't special"
    … …  
    46464643         </li>
    46474644      </ul>
    4648       <h3 id="rfc.section.D.10.9"><a href="#rfc.section.D.10.9">D.10.9</a>&nbsp;<a id="changes.3.since.07" href="#changes.3.since.07">Since draft-ietf-httpbis-p3-payload-07</a></h3>
    4649       <p id="rfc.section.D.10.9.p.1">Closed issues: </p>
     4645      <h3 id="rfc.section.D.9.9"><a href="#rfc.section.D.9.9">D.9.9</a>&nbsp;<a id="changes.3.since.07" href="#changes.3.since.07">Since draft-ietf-httpbis-p3-payload-07</a></h3>
     4646      <p id="rfc.section.D.9.9.p.1">Closed issues: </p>
    46504647      <ul>
    46514648         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/13">http://tools.ietf.org/wg/httpbis/trac/ticket/13</a>&gt;: "Updated reference for language tags"
    … …  
    46624659         </li>
    46634660      </ul>
    4664       <p id="rfc.section.D.10.9.p.2">Partly resolved issues: </p>
     4661      <p id="rfc.section.D.9.9.p.2">Partly resolved issues: </p>
    46654662      <ul>
    46664663         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/148">http://tools.ietf.org/wg/httpbis/trac/ticket/148</a>&gt;: "update IANA requirements wrt Transfer-Coding values" (add the IANA Considerations subsection)
    … …  
    46694666         </li>
    46704667      </ul>
    4671       <h3 id="rfc.section.D.10.10"><a href="#rfc.section.D.10.10">D.10.10</a>&nbsp;<a id="changes.3.since.08" href="#changes.3.since.08">Since draft-ietf-httpbis-p3-payload-08</a></h3>
    4672       <p id="rfc.section.D.10.10.p.1">Closed issues: </p>
     4668      <h3 id="rfc.section.D.9.10"><a href="#rfc.section.D.9.10">D.9.10</a>&nbsp;<a id="changes.3.since.08" href="#changes.3.since.08">Since draft-ietf-httpbis-p3-payload-08</a></h3>
     4669      <p id="rfc.section.D.9.10.p.1">Closed issues: </p>
    46734670      <ul>
    46744671         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/81">http://tools.ietf.org/wg/httpbis/trac/ticket/81</a>&gt;: "Content Negotiation for media types"
    … …  
    46774674         </li>
    46784675      </ul>
    4679       <h3 id="rfc.section.D.10.11"><a href="#rfc.section.D.10.11">D.10.11</a>&nbsp;<a id="changes.3.since.09" href="#changes.3.since.09">Since draft-ietf-httpbis-p3-payload-09</a></h3>
    4680       <p id="rfc.section.D.10.11.p.1">Closed issues: </p>
     4676      <h3 id="rfc.section.D.9.11"><a href="#rfc.section.D.9.11">D.9.11</a>&nbsp;<a id="changes.3.since.09" href="#changes.3.since.09">Since draft-ietf-httpbis-p3-payload-09</a></h3>
     4677      <p id="rfc.section.D.9.11.p.1">Closed issues: </p>
    46814678      <ul>
    46824679         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/122">http://tools.ietf.org/wg/httpbis/trac/ticket/122</a>&gt;: "MIME-Version not listed in P1, general header fields"
    … …  
    46894686         </li>
    46904687      </ul>
    4691       <p id="rfc.section.D.10.11.p.2">Partly resolved issues: </p>
     4688      <p id="rfc.section.D.9.11.p.2">Partly resolved issues: </p>
    46924689      <ul>
    46934690         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/196">http://tools.ietf.org/wg/httpbis/trac/ticket/196</a>&gt;: "Term for the requested resource's URI"
    46944691         </li>
    46954692      </ul>
    4696       <h3 id="rfc.section.D.10.12"><a href="#rfc.section.D.10.12">D.10.12</a>&nbsp;<a id="changes.3.since.10" href="#changes.3.since.10">Since draft-ietf-httpbis-p3-payload-10</a></h3>
    4697       <p id="rfc.section.D.10.12.p.1">Closed issues: </p>
     4693      <h3 id="rfc.section.D.9.12"><a href="#rfc.section.D.9.12">D.9.12</a>&nbsp;<a id="changes.3.since.10" href="#changes.3.since.10">Since draft-ietf-httpbis-p3-payload-10</a></h3>
     4694      <p id="rfc.section.D.9.12.p.1">Closed issues: </p>
    46984695      <ul>
    46994696         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/69">http://tools.ietf.org/wg/httpbis/trac/ticket/69</a>&gt;: "Clarify 'Requested Variant'"
    … …  
    47144711         </li>
    47154712      </ul>
    4716       <p id="rfc.section.D.10.12.p.2">Partly resolved issues: </p>
     4713      <p id="rfc.section.D.9.12.p.2">Partly resolved issues: </p>
    47174714      <ul>
    47184715         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/178">http://tools.ietf.org/wg/httpbis/trac/ticket/178</a>&gt;: "Content-MD5 and partial responses"
    47194716         </li>
    47204717      </ul>
    4721       <h3 id="rfc.section.D.10.13"><a href="#rfc.section.D.10.13">D.10.13</a>&nbsp;<a id="changes.3.since.11" href="#changes.3.since.11">Since draft-ietf-httpbis-p3-payload-11</a></h3>
    4722       <p id="rfc.section.D.10.13.p.1">Closed issues: </p>
     4718      <h3 id="rfc.section.D.9.13"><a href="#rfc.section.D.9.13">D.9.13</a>&nbsp;<a id="changes.3.since.11" href="#changes.3.since.11">Since draft-ietf-httpbis-p3-payload-11</a></h3>
     4719      <p id="rfc.section.D.9.13.p.1">Closed issues: </p>
    47234720      <ul>
    47244721         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/123">http://tools.ietf.org/wg/httpbis/trac/ticket/123</a>&gt;: "Factor out Content-Disposition"
    47254722         </li>
    47264723      </ul>
    4727       <h3 id="rfc.section.D.10.14"><a href="#rfc.section.D.10.14">D.10.14</a>&nbsp;<a id="changes.3.since.12" href="#changes.3.since.12">Since draft-ietf-httpbis-p3-payload-12</a></h3>
    4728       <p id="rfc.section.D.10.14.p.1">Closed issues: </p>
     4724      <h3 id="rfc.section.D.9.14"><a href="#rfc.section.D.9.14">D.9.14</a>&nbsp;<a id="changes.3.since.12" href="#changes.3.since.12">Since draft-ietf-httpbis-p3-payload-12</a></h3>
     4725      <p id="rfc.section.D.9.14.p.1">Closed issues: </p>
    47294726      <ul>
    47304727         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/224">http://tools.ietf.org/wg/httpbis/trac/ticket/224</a>&gt;: "Header Classification"
    … …  
    47354732         </li>
    47364733      </ul>
    4737       <h3 id="rfc.section.D.10.15"><a href="#rfc.section.D.10.15">D.10.15</a>&nbsp;<a id="changes.3.since.13" href="#changes.3.since.13">Since draft-ietf-httpbis-p3-payload-13</a></h3>
    4738       <p id="rfc.section.D.10.15.p.1">Closed issues: </p>
     4734      <h3 id="rfc.section.D.9.15"><a href="#rfc.section.D.9.15">D.9.15</a>&nbsp;<a id="changes.3.since.13" href="#changes.3.since.13">Since draft-ietf-httpbis-p3-payload-13</a></h3>
     4735      <p id="rfc.section.D.9.15.p.1">Closed issues: </p>
    47394736      <ul>
    47404737         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/20">http://tools.ietf.org/wg/httpbis/trac/ticket/20</a>&gt;: "Default charsets for text media types"
    … …  
    47474744         </li>
    47484745      </ul>
    4749       <h3 id="rfc.section.D.10.16"><a href="#rfc.section.D.10.16">D.10.16</a>&nbsp;<a id="changes.3.since.14" href="#changes.3.since.14">Since draft-ietf-httpbis-p3-payload-14</a></h3>
    4750       <p id="rfc.section.D.10.16.p.1">None.</p>
    4751       <h3 id="rfc.section.D.10.17"><a href="#rfc.section.D.10.17">D.10.17</a>&nbsp;<a id="changes.3.since.15" href="#changes.3.since.15">Since draft-ietf-httpbis-p3-payload-15</a></h3>
    4752       <p id="rfc.section.D.10.17.p.1">Closed issues: </p>
     4746      <h3 id="rfc.section.D.9.16"><a href="#rfc.section.D.9.16">D.9.16</a>&nbsp;<a id="changes.3.since.14" href="#changes.3.since.14">Since draft-ietf-httpbis-p3-payload-14</a></h3>
     4747      <p id="rfc.section.D.9.16.p.1">None.</p>
     4748      <h3 id="rfc.section.D.9.17"><a href="#rfc.section.D.9.17">D.9.17</a>&nbsp;<a id="changes.3.since.15" href="#changes.3.since.15">Since draft-ietf-httpbis-p3-payload-15</a></h3>
     4749      <p id="rfc.section.D.9.17.p.1">Closed issues: </p>
    47534750      <ul>
    47544751         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/285">http://tools.ietf.org/wg/httpbis/trac/ticket/285</a>&gt;: "Strength of requirements on Accept re: 406"
    47554752         </li>
    47564753      </ul>
    4757       <h3 id="rfc.section.D.10.18"><a href="#rfc.section.D.10.18">D.10.18</a>&nbsp;<a id="changes.3.since.16" href="#changes.3.since.16">Since draft-ietf-httpbis-p3-payload-16</a></h3>
    4758       <p id="rfc.section.D.10.18.p.1">Closed issues: </p>
     4754      <h3 id="rfc.section.D.9.18"><a href="#rfc.section.D.9.18">D.9.18</a>&nbsp;<a id="changes.3.since.16" href="#changes.3.since.16">Since draft-ietf-httpbis-p3-payload-16</a></h3>
     4755      <p id="rfc.section.D.9.18.p.1">Closed issues: </p>
    47594756      <ul>
    47604757         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/186">http://tools.ietf.org/wg/httpbis/trac/ticket/186</a>&gt;: "Document HTTP's error-handling philosophy"
    47614758         </li>
    47624759      </ul>
    4763       <h3 id="rfc.section.D.10.19"><a href="#rfc.section.D.10.19">D.10.19</a>&nbsp;<a id="changes.3.since.17" href="#changes.3.since.17">Since draft-ietf-httpbis-p3-payload-17</a></h3>
    4764       <p id="rfc.section.D.10.19.p.1">Closed issues: </p>
     4760      <h3 id="rfc.section.D.9.19"><a href="#rfc.section.D.9.19">D.9.19</a>&nbsp;<a id="changes.3.since.17" href="#changes.3.since.17">Since draft-ietf-httpbis-p3-payload-17</a></h3>
     4761      <p id="rfc.section.D.9.19.p.1">Closed issues: </p>
    47654762      <ul>
    47664763         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/323">http://tools.ietf.org/wg/httpbis/trac/ticket/323</a>&gt;: "intended maturity level vs normative references"
    47674764         </li>
    47684765      </ul>
    4769       <h3 id="rfc.section.D.10.20"><a href="#rfc.section.D.10.20">D.10.20</a>&nbsp;<a id="changes.3.since.18" href="#changes.3.since.18">Since draft-ietf-httpbis-p3-payload-18</a></h3>
    4770       <p id="rfc.section.D.10.20.p.1">Closed issues: </p>
     4766      <h3 id="rfc.section.D.9.20"><a href="#rfc.section.D.9.20">D.9.20</a>&nbsp;<a id="changes.3.since.18" href="#changes.3.since.18">Since draft-ietf-httpbis-p3-payload-18</a></h3>
     4767      <p id="rfc.section.D.9.20.p.1">Closed issues: </p>
    47714768      <ul>
    47724769         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/330">http://tools.ietf.org/wg/httpbis/trac/ticket/330</a>&gt;: "is ETag a representation header field?"
    … …  
    47774774         </li>
    47784775      </ul>
    4779       <h3 id="rfc.section.D.10.21"><a href="#rfc.section.D.10.21">D.10.21</a>&nbsp;<a id="changes.3.since.19" href="#changes.3.since.19">Since draft-ietf-httpbis-p3-payload-19</a></h3>
    4780       <p id="rfc.section.D.10.21.p.1">None yet.</p>
     4776      <h3 id="rfc.section.D.9.21"><a href="#rfc.section.D.9.21">D.9.21</a>&nbsp;<a id="changes.3.since.19" href="#changes.3.since.19">Since draft-ietf-httpbis-p3-payload-19</a></h3>
     4777      <p id="rfc.section.D.9.21.p.1">None yet.</p>
    47814778      <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1>
    47824779      <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>
    … …  
    47864783            <li><a id="rfc.index.1" href="#rfc.index.1"><b>1</b></a><ul>
    47874784                  <li>100 Continue (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.100.1">4.1</a>, <a href="#rfc.iref.21"><b>4.3.1</b></a>, <a href="#rfc.xref.status.100.2">8.2</a></li>
    4788                   <li>100-continue (expect value)&nbsp;&nbsp;<a href="#rfc.iref.103"><b>7.3</b></a></li>
     4785                  <li>100-continue (expect value)&nbsp;&nbsp;<a href="#rfc.iref.132"><b>7.11</b></a></li>
    47894786                  <li>101 Switching Protocols (status code)&nbsp;&nbsp;<a href="#rfc.xref.status.101.1">4.1</a>, <a href="#rfc.iref.22"><b>4.3.2</b></a>, <a href="#rfc.xref.status.101.2">8.2</a></li>
    47904787               </ul>
    … …  
    48374834            </li>
    48384835            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
    4839                   <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">3.2</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">8.3</a>, <a href="#rfc.xref.header.accept.4">D.3.1</a>, <a href="#rfc.iref.a.2"><b>D.4.1</b></a></li>
    4840                   <li>Accept-Charset header field&nbsp;&nbsp;<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.3.1</a>, <a href="#rfc.iref.a.3"><b>D.4.2</b></a>, <a href="#rfc.xref.header.accept-charset.4">D.9</a></li>
    4841                   <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">8.3</a>, <a href="#rfc.xref.header.accept-encoding.4">D.3.1</a>, <a href="#rfc.iref.a.4"><b>D.4.3</b></a>, <a href="#rfc.xref.header.accept-encoding.5">D.5.1</a></li>
    4842                   <li>Accept-Language header field&nbsp;&nbsp;<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.3.1</a>, <a href="#rfc.iref.a.5"><b>D.4.4</b></a></li>
    4843                   <li>Allow header field&nbsp;&nbsp;<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>
     4836                  <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">3.2</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.iref.a.1"><b>7.1</b></a>, <a href="#rfc.xref.header.accept.3">8.3</a>, <a href="#rfc.xref.header.accept.4">D.3.1</a></li>
     4837                  <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">3.2</a>, <a href="#rfc.iref.a.2"><b>7.2</b></a>, <a href="#rfc.xref.header.accept-charset.2">8.3</a>, <a href="#rfc.xref.header.accept-charset.3">D.3.1</a>, <a href="#rfc.xref.header.accept-charset.4">D.8</a></li>
     4838                  <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.iref.a.3"><b>7.3</b></a>, <a href="#rfc.xref.header.accept-encoding.3">8.3</a>, <a href="#rfc.xref.header.accept-encoding.4">D.3.1</a>, <a href="#rfc.xref.header.accept-encoding.5">D.4.1</a></li>
     4839                  <li>Accept-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">3.2</a>, <a href="#rfc.iref.a.4"><b>7.4</b></a>, <a href="#rfc.xref.header.accept-language.2">8.3</a>, <a href="#rfc.xref.header.accept-language.3">D.3.1</a></li>
     4840                  <li>Allow header field&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">2</a>, <a href="#rfc.xref.header.allow.2">3.3</a>, <a href="#rfc.iref.a.5"><b>7.5</b></a>, <a href="#rfc.xref.header.allow.3">8.3</a>, <a href="#rfc.xref.header.allow.4">A</a></li>
    48444841               </ul>
    48454842            </li>
    … …  
    48554852                  <li>CONNECT method&nbsp;&nbsp;<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>
    48564853                  <li>content negotiation&nbsp;&nbsp;<a href="#rfc.iref.c.1">1.1</a></li>
    4857                   <li>Content-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.3</a>, <a href="#rfc.xref.header.content-encoding.3">D.2.1</a>, <a href="#rfc.iref.c.7"><b>D.4.5</b></a>, <a href="#rfc.xref.header.content-encoding.4">D.4.5</a></li>
    4858                   <li>Content-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">8.3</a>, <a href="#rfc.xref.header.content-language.2">D.2.1</a>, <a href="#rfc.iref.c.8"><b>D.4.6</b></a></li>
    4859                   <li>Content-Location header field&nbsp;&nbsp;<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.2.1</a>, <a href="#rfc.iref.c.9"><b>D.4.7</b></a>, <a href="#rfc.xref.header.content-location.5">D.9</a></li>
    4860                   <li>Content-Transfer-Encoding header field&nbsp;&nbsp;<a href="#rfc.iref.c.11">D.7.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">D.9</a></li>
    4861                   <li>Content-Type header field&nbsp;&nbsp;<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">6.5</a>, <a href="#rfc.xref.header.content-type.4">8.3</a>, <a href="#rfc.xref.header.content-type.5">D.2.1</a>, <a href="#rfc.iref.c.10"><b>D.4.8</b></a></li>
     4854                  <li>Content-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.iref.c.7"><b>7.6</b></a>, <a href="#rfc.xref.header.content-encoding.2">7.6</a>, <a href="#rfc.xref.header.content-encoding.3">8.3</a>, <a href="#rfc.xref.header.content-encoding.4">D.2.1</a></li>
     4855                  <li>Content-Language header field&nbsp;&nbsp;<a href="#rfc.iref.c.8"><b>7.7</b></a>, <a href="#rfc.xref.header.content-language.1">8.3</a>, <a href="#rfc.xref.header.content-language.2">D.2.1</a></li>
     4856                  <li>Content-Location header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">2.3.4</a>, <a href="#rfc.iref.c.9"><b>7.8</b></a>, <a href="#rfc.xref.header.content-location.2">7.13</a>, <a href="#rfc.xref.header.content-location.3">8.3</a>, <a href="#rfc.xref.header.content-location.4">D.2.1</a>, <a href="#rfc.xref.header.content-location.5">D.8</a></li>
     4857                  <li>Content-Transfer-Encoding header field&nbsp;&nbsp;<a href="#rfc.iref.c.11">D.6.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">D.8</a></li>
     4858                  <li>Content-Type header field&nbsp;&nbsp;<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">6.5</a>, <a href="#rfc.iref.c.10"><b>7.9</b></a>, <a href="#rfc.xref.header.content-type.4">8.3</a>, <a href="#rfc.xref.header.content-type.5">D.2.1</a></li>
    48624859               </ul>
    48634860            </li>
    48644861            <li><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul>
    4865                   <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.3</a>, <a href="#rfc.iref.d.3"><b>7.2</b></a>, <a href="#rfc.xref.header.date.2">8.3</a></li>
     4862                  <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.3</a>, <a href="#rfc.iref.d.3"><b>7.10</b></a>, <a href="#rfc.xref.header.date.2">8.3</a></li>
    48664863                  <li>deflate (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.d.2">6.4</a></li>
    48674864                  <li>DELETE method&nbsp;&nbsp;<a href="#rfc.iref.d.1"><b>2.3.6</b></a>, <a href="#rfc.xref.DELETE.1">8.1</a></li>
    … …  
    48704867            </li>
    48714868            <li><a id="rfc.index.E" href="#rfc.index.E"><b>E</b></a><ul>
    4872                   <li>Expect header field&nbsp;&nbsp;<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.e.1"><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>
     4869                  <li>Expect header field&nbsp;&nbsp;<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.e.1"><b>7.11</b></a>, <a href="#rfc.xref.header.expect.3">8.3</a>, <a href="#rfc.xref.header.expect.4">A</a></li>
    48734870                  <li>Expect Values&nbsp;&nbsp;
    48744871                     <ul>
    4875                         <li>100-continue&nbsp;&nbsp;<a href="#rfc.iref.e.2"><b>7.3</b></a></li>
     4872                        <li>100-continue&nbsp;&nbsp;<a href="#rfc.iref.e.2"><b>7.11</b></a></li>
    48764873                     </ul>
    48774874                  </li>
    … …  
    48794876            </li>
    48804877            <li><a id="rfc.index.F" href="#rfc.index.F"><b>F</b></a><ul>
    4881                   <li>From header field&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">3.2</a>, <a href="#rfc.iref.f.1"><b>7.4</b></a>, <a href="#rfc.xref.header.from.2">8.3</a></li>
     4878                  <li>From header field&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">3.2</a>, <a href="#rfc.iref.f.1"><b>7.12</b></a>, <a href="#rfc.xref.header.from.2">8.3</a></li>
    48824879               </ul>
    48834880            </li>
    … …  
    48864883                  <li><tt>Grammar</tt>&nbsp;&nbsp;
    48874884                     <ul>
    4888                         <li><tt>Accept</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.46"><b>D.4.1</b></a></li>
    4889                         <li><tt>Accept-Charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.50"><b>D.4.2</b></a></li>
    4890                         <li><tt>Accept-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.51"><b>D.4.3</b></a></li>
    4891                         <li><tt>accept-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.49"><b>D.4.1</b></a></li>
    4892                         <li><tt>Accept-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.53"><b>D.4.4</b></a></li>
    4893                         <li><tt>accept-params</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.48"><b>D.4.1</b></a></li>
    4894                         <li><tt>Allow</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.31"><b>7.1</b></a></li>
     4885                        <li><tt>Accept</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.31"><b>7.1</b></a></li>
     4886                        <li><tt>Accept-Charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.35"><b>7.2</b></a></li>
     4887                        <li><tt>Accept-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.36"><b>7.3</b></a></li>
     4888                        <li><tt>accept-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.34"><b>7.1</b></a></li>
     4889                        <li><tt>Accept-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.38"><b>7.4</b></a></li>
     4890                        <li><tt>accept-params</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.33"><b>7.1</b></a></li>
     4891                        <li><tt>Allow</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.40"><b>7.5</b></a></li>
    48954892                        <li><tt>asctime-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>6.1</b></a></li>
    48964893                        <li><tt>attribute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.28"><b>6.5</b></a></li>
    48974894                        <li><tt>charset</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.21"><b>6.3</b></a></li>
    4898                         <li><tt>codings</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.52"><b>D.4.3</b></a></li>
     4895                        <li><tt>codings</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.37"><b>7.3</b></a></li>
    48994896                        <li><tt>content-coding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.22"><b>6.4</b></a></li>
    4900                         <li><tt>Content-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.55"><b>D.4.5</b></a></li>
    4901                         <li><tt>Content-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.56"><b>D.4.6</b></a></li>
    4902                         <li><tt>Content-Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.57"><b>D.4.7</b></a></li>
    4903                         <li><tt>Content-Type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.58"><b>D.4.8</b></a></li>
    4904                         <li><tt>Date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.32"><b>7.2</b></a></li>
     4897                        <li><tt>Content-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.41"><b>7.6</b></a></li>
     4898                        <li><tt>Content-Language</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.42"><b>7.7</b></a></li>
     4899                        <li><tt>Content-Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.43"><b>7.8</b></a></li>
     4900                        <li><tt>Content-Type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.44"><b>7.9</b></a></li>
     4901                        <li><tt>Date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.45"><b>7.10</b></a></li>
    49054902                        <li><tt>date1</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>6.1</b></a></li>
    49064903                        <li><tt>day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>6.1</b></a></li>
    49074904                        <li><tt>day-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>6.1</b></a></li>
    49084905                        <li><tt>day-name-l</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>6.1</b></a></li>
    4909                         <li><tt>delta-seconds</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.43"><b>7.8</b></a></li>
    4910                         <li><tt>Expect</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.33"><b>7.3</b></a></li>
    4911                         <li><tt>expect-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.37"><b>7.3</b></a></li>
    4912                         <li><tt>expect-param</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.35"><b>7.3</b></a></li>
    4913                         <li><tt>expect-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.36"><b>7.3</b></a></li>
    4914                         <li><tt>expectation</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.34"><b>7.3</b></a></li>
    4915                         <li><tt>From</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.38"><b>7.4</b></a></li>
     4906                        <li><tt>delta-seconds</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.56"><b>7.16</b></a></li>
     4907                        <li><tt>Expect</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.46"><b>7.11</b></a></li>
     4908                        <li><tt>expect-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.50"><b>7.11</b></a></li>
     4909                        <li><tt>expect-param</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.48"><b>7.11</b></a></li>
     4910                        <li><tt>expect-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.49"><b>7.11</b></a></li>
     4911                        <li><tt>expectation</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.47"><b>7.11</b></a></li>
     4912                        <li><tt>From</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.51"><b>7.12</b></a></li>
    49164913                        <li><tt>GMT</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>6.1</b></a></li>
    49174914                        <li><tt>hour</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>6.1</b></a></li>
    49184915                        <li><tt>HTTP-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>6.1</b></a></li>
    4919                         <li><tt>language-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.54"><b>D.4.4</b></a></li>
     4916                        <li><tt>language-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.39"><b>7.4</b></a></li>
    49204917                        <li><tt>language-tag</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.30"><b>6.6</b></a></li>
    4921                         <li><tt>Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.39"><b>7.5</b></a></li>
    4922                         <li><tt>Max-Forwards</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.40"><b>7.6</b></a></li>
    4923                         <li><tt>media-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.47"><b>D.4.1</b></a></li>
     4918                        <li><tt>Location</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.52"><b>7.13</b></a></li>
     4919                        <li><tt>Max-Forwards</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.53"><b>7.14</b></a></li>
     4920                        <li><tt>media-range</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.32"><b>7.1</b></a></li>
    49244921                        <li><tt>media-type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.24"><b>6.5</b></a></li>
    49254922                        <li><tt>method</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>2</b></a></li>
    4926                         <li><tt>MIME-Version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.59"><b>D.7.1</b></a></li>
     4923                        <li><tt>MIME-Version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.59"><b>D.6.1</b></a></li>
    49274924                        <li><tt>minute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>6.1</b></a></li>
    49284925                        <li><tt>month</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>6.1</b></a></li>
    … …  
    49314928                        <li><tt>product</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>6.2</b></a></li>
    49324929                        <li><tt>product-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.20"><b>6.2</b></a></li>
    4933                         <li><tt>Referer</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.41"><b>7.7</b></a></li>
    4934                         <li><tt>Retry-After</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.42"><b>7.8</b></a></li>
     4930                        <li><tt>Referer</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.54"><b>7.15</b></a></li>
     4931                        <li><tt>Retry-After</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.55"><b>7.16</b></a></li>
    49354932                        <li><tt>rfc1123-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>6.1</b></a></li>
    49364933                        <li><tt>rfc850-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>6.1</b></a></li>
    49374934                        <li><tt>second</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>6.1</b></a></li>
    4938                         <li><tt>Server</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.44"><b>7.9</b></a></li>
     4935                        <li><tt>Server</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.57"><b>7.17</b></a></li>
    49394936                        <li><tt>subtype</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.26"><b>6.5</b></a></li>
    49404937                        <li><tt>time-of-day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>6.1</b></a></li>
    49414938                        <li><tt>type</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.25"><b>6.5</b></a></li>
    4942                         <li><tt>User-Agent</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.45"><b>7.10</b></a></li>
     4939                        <li><tt>User-Agent</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.58"><b>7.18</b></a></li>
    49434940                        <li><tt>value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.29"><b>6.5</b></a></li>
    49444941                        <li><tt>year</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>6.1</b></a></li>
    … …  
    49524949                  <li>Header Fields&nbsp;&nbsp;
    49534950                     <ul>
    4954                         <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">3.2</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">8.3</a>, <a href="#rfc.xref.header.accept.4">D.3.1</a>, <a href="#rfc.iref.h.12"><b>D.4.1</b></a></li>
    4955                         <li>Accept-Charset&nbsp;&nbsp;<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.3.1</a>, <a href="#rfc.iref.h.13"><b>D.4.2</b></a>, <a href="#rfc.xref.header.accept-charset.4">D.9</a></li>
    4956                         <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">8.3</a>, <a href="#rfc.xref.header.accept-encoding.4">D.3.1</a>, <a href="#rfc.iref.h.14"><b>D.4.3</b></a>, <a href="#rfc.xref.header.accept-encoding.5">D.5.1</a></li>
    4957                         <li>Accept-Language&nbsp;&nbsp;<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.3.1</a>, <a href="#rfc.iref.h.15"><b>D.4.4</b></a></li>
    4958                         <li>Allow&nbsp;&nbsp;<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>
    4959                         <li>Content-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.3</a>, <a href="#rfc.xref.header.content-encoding.3">D.2.1</a>, <a href="#rfc.iref.h.16"><b>D.4.5</b></a>, <a href="#rfc.xref.header.content-encoding.4">D.4.5</a></li>
    4960                         <li>Content-Language&nbsp;&nbsp;<a href="#rfc.xref.header.content-language.1">8.3</a>, <a href="#rfc.xref.header.content-language.2">D.2.1</a>, <a href="#rfc.iref.h.17"><b>D.4.6</b></a></li>
    4961                         <li>Content-Location&nbsp;&nbsp;<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.2.1</a>, <a href="#rfc.iref.h.18"><b>D.4.7</b></a>, <a href="#rfc.xref.header.content-location.5">D.9</a></li>
    4962                         <li>Content-Transfer-Encoding&nbsp;&nbsp;<a href="#rfc.iref.h.21">D.7.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">D.9</a></li>
    4963                         <li>Content-Type&nbsp;&nbsp;<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">6.5</a>, <a href="#rfc.xref.header.content-type.4">8.3</a>, <a href="#rfc.xref.header.content-type.5">D.2.1</a>, <a href="#rfc.iref.h.19"><b>D.4.8</b></a></li>
    4964                         <li>Date&nbsp;&nbsp;<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>
    4965                         <li>Expect&nbsp;&nbsp;<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>
    4966                         <li>From&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">3.2</a>, <a href="#rfc.iref.h.5"><b>7.4</b></a>, <a href="#rfc.xref.header.from.2">8.3</a></li>
    4967                         <li>Location&nbsp;&nbsp;<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>
    4968                         <li>Max-Forwards&nbsp;&nbsp;<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>
    4969                         <li>MIME-Version&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">8.3</a>, <a href="#rfc.iref.h.20"><b>D.7.1</b></a></li>
    4970                         <li>Referer&nbsp;&nbsp;<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>
    4971                         <li>Retry-After&nbsp;&nbsp;<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>
    4972                         <li>Server&nbsp;&nbsp;<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>
    4973                         <li>User-Agent&nbsp;&nbsp;<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.3.1</a></li>
     4951                        <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">3.2</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.iref.h.2"><b>7.1</b></a>, <a href="#rfc.xref.header.accept.3">8.3</a>, <a href="#rfc.xref.header.accept.4">D.3.1</a></li>
     4952                        <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">3.2</a>, <a href="#rfc.iref.h.3"><b>7.2</b></a>, <a href="#rfc.xref.header.accept-charset.2">8.3</a>, <a href="#rfc.xref.header.accept-charset.3">D.3.1</a>, <a href="#rfc.xref.header.accept-charset.4">D.8</a></li>
     4953                        <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.iref.h.4"><b>7.3</b></a>, <a href="#rfc.xref.header.accept-encoding.3">8.3</a>, <a href="#rfc.xref.header.accept-encoding.4">D.3.1</a>, <a href="#rfc.xref.header.accept-encoding.5">D.4.1</a></li>
     4954                        <li>Accept-Language&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">3.2</a>, <a href="#rfc.iref.h.5"><b>7.4</b></a>, <a href="#rfc.xref.header.accept-language.2">8.3</a>, <a href="#rfc.xref.header.accept-language.3">D.3.1</a></li>
     4955                        <li>Allow&nbsp;&nbsp;<a href="#rfc.xref.header.allow.1">2</a>, <a href="#rfc.xref.header.allow.2">3.3</a>, <a href="#rfc.iref.h.6"><b>7.5</b></a>, <a href="#rfc.xref.header.allow.3">8.3</a>, <a href="#rfc.xref.header.allow.4">A</a></li>
     4956                        <li>Content-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.iref.h.7"><b>7.6</b></a>, <a href="#rfc.xref.header.content-encoding.2">7.6</a>, <a href="#rfc.xref.header.content-encoding.3">8.3</a>, <a href="#rfc.xref.header.content-encoding.4">D.2.1</a></li>
     4957                        <li>Content-Language&nbsp;&nbsp;<a href="#rfc.iref.h.8"><b>7.7</b></a>, <a href="#rfc.xref.header.content-language.1">8.3</a>, <a href="#rfc.xref.header.content-language.2">D.2.1</a></li>
     4958                        <li>Content-Location&nbsp;&nbsp;<a href="#rfc.xref.header.content-location.1">2.3.4</a>, <a href="#rfc.iref.h.9"><b>7.8</b></a>, <a href="#rfc.xref.header.content-location.2">7.13</a>, <a href="#rfc.xref.header.content-location.3">8.3</a>, <a href="#rfc.xref.header.content-location.4">D.2.1</a>, <a href="#rfc.xref.header.content-location.5">D.8</a></li>
     4959                        <li>Content-Transfer-Encoding&nbsp;&nbsp;<a href="#rfc.iref.h.21">D.6.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">D.8</a></li>
     4960                        <li>Content-Type&nbsp;&nbsp;<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">6.5</a>, <a href="#rfc.iref.h.10"><b>7.9</b></a>, <a href="#rfc.xref.header.content-type.4">8.3</a>, <a href="#rfc.xref.header.content-type.5">D.2.1</a></li>
     4961                        <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.3</a>, <a href="#rfc.iref.h.11"><b>7.10</b></a>, <a href="#rfc.xref.header.date.2">8.3</a></li>
     4962                        <li>Expect&nbsp;&nbsp;<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.12"><b>7.11</b></a>, <a href="#rfc.xref.header.expect.3">8.3</a>, <a href="#rfc.xref.header.expect.4">A</a></li>
     4963                        <li>From&nbsp;&nbsp;<a href="#rfc.xref.header.from.1">3.2</a>, <a href="#rfc.iref.h.13"><b>7.12</b></a>, <a href="#rfc.xref.header.from.2">8.3</a></li>
     4964                        <li>Location&nbsp;&nbsp;<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.14"><b>7.13</b></a>, <a href="#rfc.xref.header.location.4">8.3</a>, <a href="#rfc.xref.header.location.5">A</a></li>
     4965                        <li>Max-Forwards&nbsp;&nbsp;<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.15"><b>7.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">8.3</a>, <a href="#rfc.xref.header.max-forwards.5">A</a></li>
     4966                        <li>MIME-Version&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">8.3</a>, <a href="#rfc.iref.h.20"><b>D.6.1</b></a></li>
     4967                        <li>Referer&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">3.2</a>, <a href="#rfc.iref.h.16"><b>7.15</b></a>, <a href="#rfc.xref.header.referer.2">8.3</a>, <a href="#rfc.xref.header.referer.3">A</a></li>
     4968                        <li>Retry-After&nbsp;&nbsp;<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.17"><b>7.16</b></a>, <a href="#rfc.xref.header.retry-after.3">8.3</a></li>
     4969                        <li>Server&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">3.3</a>, <a href="#rfc.iref.h.18"><b>7.17</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>
     4970                        <li>User-Agent&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">3.2</a>, <a href="#rfc.iref.h.19"><b>7.18</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.3.1</a></li>
    49744971                     </ul>
    49754972                  </li>
    … …  
    49814978            </li>
    49824979            <li><a id="rfc.index.L" href="#rfc.index.L"><b>L</b></a><ul>
    4983                   <li>Location header field&nbsp;&nbsp;<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.l.1"><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>
     4980                  <li>Location header field&nbsp;&nbsp;<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.l.1"><b>7.13</b></a>, <a href="#rfc.xref.header.location.4">8.3</a>, <a href="#rfc.xref.header.location.5">A</a></li>
    49844981               </ul>
    49854982            </li>
    49864983            <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul>
    4987                   <li>Max-Forwards header field&nbsp;&nbsp;<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.m.9"><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>
     4984                  <li>Max-Forwards header field&nbsp;&nbsp;<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.m.9"><b>7.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">8.3</a>, <a href="#rfc.xref.header.max-forwards.5">A</a></li>
    49884985                  <li>Methods&nbsp;&nbsp;
    49894986                     <ul>
    … …  
    49924989                        <li>GET&nbsp;&nbsp;<a href="#rfc.iref.m.2"><b>2.3.2</b></a>, <a href="#rfc.xref.GET.1">8.1</a></li>
    49934990                        <li>HEAD&nbsp;&nbsp;<a href="#rfc.iref.m.3"><b>2.3.3</b></a>, <a href="#rfc.xref.HEAD.1">8.1</a></li>
    4994                         <li>OPTIONS&nbsp;&nbsp;<a href="#rfc.iref.m.1"><b>2.3.1</b></a>, <a href="#rfc.xref.OPTIONS.1">7.6</a>, <a href="#rfc.xref.OPTIONS.2">8.1</a></li>
     4991                        <li>OPTIONS&nbsp;&nbsp;<a href="#rfc.iref.m.1"><b>2.3.1</b></a>, <a href="#rfc.xref.OPTIONS.1">7.14</a>, <a href="#rfc.xref.OPTIONS.2">8.1</a></li>
    49954992                        <li>POST&nbsp;&nbsp;<a href="#rfc.iref.m.4"><b>2.3.4</b></a>, <a href="#rfc.xref.POST.1">8.1</a>, <a href="#rfc.xref.POST.2">A</a></li>
    49964993                        <li>PUT&nbsp;&nbsp;<a href="#rfc.iref.m.5"><b>2.3.5</b></a>, <a href="#rfc.xref.PUT.1">8.1</a>, <a href="#rfc.xref.PUT.2">A</a></li>
    4997                         <li>TRACE&nbsp;&nbsp;<a href="#rfc.iref.m.7"><b>2.3.7</b></a>, <a href="#rfc.xref.TRACE.1">7.6</a>, <a href="#rfc.xref.TRACE.2">8.1</a>, <a href="#rfc.xref.TRACE.3">9.1</a></li>
     4994                        <li>TRACE&nbsp;&nbsp;<a href="#rfc.iref.m.7"><b>2.3.7</b></a>, <a href="#rfc.xref.TRACE.1">7.14</a>, <a href="#rfc.xref.TRACE.2">8.1</a>, <a href="#rfc.xref.TRACE.3">9.1</a></li>
    49984995                     </ul>
    49994996                  </li>
    5000                   <li>MIME-Version header field&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">8.3</a>, <a href="#rfc.iref.m.10"><b>D.7.1</b></a></li>
     4997                  <li>MIME-Version header field&nbsp;&nbsp;<a href="#rfc.xref.mime-version.1">8.3</a>, <a href="#rfc.iref.m.10"><b>D.6.1</b></a></li>
    50014998               </ul>
    50024999            </li>
    50035000            <li><a id="rfc.index.O" href="#rfc.index.O"><b>O</b></a><ul>
    5004                   <li>OPTIONS method&nbsp;&nbsp;<a href="#rfc.iref.o.1"><b>2.3.1</b></a>, <a href="#rfc.xref.OPTIONS.1">7.6</a>, <a href="#rfc.xref.OPTIONS.2">8.1</a></li>
     5001                  <li>OPTIONS method&nbsp;&nbsp;<a href="#rfc.iref.o.1"><b>2.3.1</b></a>, <a href="#rfc.xref.OPTIONS.1">7.14</a>, <a href="#rfc.xref.OPTIONS.2">8.1</a></li>
    50055002               </ul>
    50065003            </li>
    50075004            <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul>
    5008                   <li><em>Part1</em>&nbsp;&nbsp;<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">6.4</a>, <a href="#rfc.xref.Part1.40">6.4</a>, <a href="#rfc.xref.Part1.41">6.4</a>, <a href="#rfc.xref.Part1.42">6.4.1</a>, <a href="#rfc.xref.Part1.43">6.4.1</a>, <a href="#rfc.xref.Part1.44">7.3</a>, <a href="#rfc.xref.Part1.45">7.9</a>, <a href="#rfc.xref.Part1.46">7.9</a>, <a href="#rfc.xref.Part1.47">7.10</a>, <a href="#rfc.xref.Part1.48">10</a>, <a href="#Part1"><b>11.1</b></a>, <a href="#rfc.xref.Part1.49">A</a>, <a href="#rfc.xref.Part1.50">D.1.1</a>, <a href="#rfc.xref.Part1.51">D.1.2</a>, <a href="#rfc.xref.Part1.52">D.3.1</a>, <a href="#rfc.xref.Part1.53">D.4.1</a>, <a href="#rfc.xref.Part1.54">D.4.3</a>, <a href="#rfc.xref.Part1.55">D.4.7</a>, <a href="#rfc.xref.Part1.56">D.5.1</a>, <a href="#rfc.xref.Part1.57">D.5.1</a>, <a href="#rfc.xref.Part1.58">D.5.1</a>, <a href="#rfc.xref.Part1.59">D.7.6</a><ul>
     5005                  <li><em>Part1</em>&nbsp;&nbsp;<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">6.4</a>, <a href="#rfc.xref.Part1.40">6.4</a>, <a href="#rfc.xref.Part1.41">6.4</a>, <a href="#rfc.xref.Part1.42">6.4.1</a>, <a href="#rfc.xref.Part1.43">6.4.1</a>, <a href="#rfc.xref.Part1.44">7.1</a>, <a href="#rfc.xref.Part1.45">7.3</a>, <a href="#rfc.xref.Part1.46">7.8</a>, <a href="#rfc.xref.Part1.47">7.11</a>, <a href="#rfc.xref.Part1.48">7.17</a>, <a href="#rfc.xref.Part1.49">7.17</a>, <a href="#rfc.xref.Part1.50">7.18</a>, <a href="#rfc.xref.Part1.51">10</a>, <a href="#Part1"><b>11.1</b></a>, <a href="#rfc.xref.Part1.52">A</a>, <a href="#rfc.xref.Part1.53">D.1.1</a>, <a href="#rfc.xref.Part1.54">D.1.2</a>, <a href="#rfc.xref.Part1.55">D.3.1</a>, <a href="#rfc.xref.Part1.56">D.4.1</a>, <a href="#rfc.xref.Part1.57">D.4.1</a>, <a href="#rfc.xref.Part1.58">D.4.1</a>, <a href="#rfc.xref.Part1.59">D.6.6</a><ul>
    50095006                        <li><em>Section 1.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.3">1.3</a></li>
    50105007                        <li><em>Section 2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.2">1.2</a></li>
    … …  
    50135010                        <li><em>Section 2.7</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.12">1.3.2</a>, <a href="#rfc.xref.Part1.14">1.3.2</a>, <a href="#rfc.xref.Part1.15">1.3.2</a></li>
    50145011                        <li><em>Section 3.2.1</em>&nbsp;&nbsp;<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></li>
    5015                         <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.22">3</a>, <a href="#rfc.xref.Part1.25">3.1</a>, <a href="#rfc.xref.Part1.45">7.9</a>, <a href="#rfc.xref.Part1.47">7.10</a></li>
     5012                        <li><em>Section 3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.22">3</a>, <a href="#rfc.xref.Part1.25">3.1</a>, <a href="#rfc.xref.Part1.48">7.17</a>, <a href="#rfc.xref.Part1.50">7.18</a></li>
    50165013                        <li><em>Section 3.2.4</em>&nbsp;&nbsp;<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>
    50175014                        <li><em>Section 3.2.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.23">3.1</a></li>
    5018                         <li><em>Section 3.3</em>&nbsp;&nbsp;<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.1.2</a></li>
    5019                         <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.59">D.7.6</a></li>
    5020                         <li><em>Section 3.3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.50">D.1.1</a></li>
     5015                        <li><em>Section 3.3</em>&nbsp;&nbsp;<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.Part1.54">D.1.2</a></li>
     5016                        <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.59">D.6.6</a></li>
     5017                        <li><em>Section 3.3.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.53">D.1.1</a></li>
    50215018                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.42">6.4.1</a></li>
    50225019                        <li><em>Section 4.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.27">3.1</a></li>
    5023                         <li><em>Section 4.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.39">6.4</a>, <a href="#rfc.xref.Part1.56">D.5.1</a></li>
     5020                        <li><em>Section 4.2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.39">6.4</a>, <a href="#rfc.xref.Part1.56">D.4.1</a></li>
    50245021                        <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.43">6.4.1</a></li>
    5025                         <li><em>Section 4.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.40">6.4</a>, <a href="#rfc.xref.Part1.57">D.5.1</a></li>
    5026                         <li><em>Section 4.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.41">6.4</a>, <a href="#rfc.xref.Part1.58">D.5.1</a></li>
     5022                        <li><em>Section 4.2.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.40">6.4</a>, <a href="#rfc.xref.Part1.57">D.4.1</a></li>
     5023                        <li><em>Section 4.2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.41">6.4</a>, <a href="#rfc.xref.Part1.58">D.4.1</a></li>
    50275024                        <li><em>Section 4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.29">3.2</a></li>
    5028                         <li><em>Section 4.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.52">D.3.1</a>, <a href="#rfc.xref.Part1.53">D.4.1</a>, <a href="#rfc.xref.Part1.54">D.4.3</a></li>
     5025                        <li><em>Section 4.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.44">7.1</a>, <a href="#rfc.xref.Part1.45">7.3</a>, <a href="#rfc.xref.Part1.55">D.3.1</a></li>
    50295026                        <li><em>Section 5.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.18">2.3.1</a>, <a href="#rfc.xref.Part1.21">2.3.8</a></li>
    50305027                        <li><em>Section 5.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.28">3.2</a></li>
    5031                         <li><em>Section 5.5</em>&nbsp;&nbsp;<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.4.7</a></li>
     5028                        <li><em>Section 5.5</em>&nbsp;&nbsp;<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.Part1.46">7.8</a></li>
    50325029                        <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.26">3.1</a></li>
    5033                         <li><em>Section 6.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.19">2.3.7</a>, <a href="#rfc.xref.Part1.46">7.9</a>, <a href="#rfc.xref.Part1.49">A</a></li>
    5034                         <li><em>Section 6.4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.31">4.3.1</a>, <a href="#rfc.xref.Part1.44">7.3</a></li>
     5030                        <li><em>Section 6.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.19">2.3.7</a>, <a href="#rfc.xref.Part1.49">7.17</a>, <a href="#rfc.xref.Part1.52">A</a></li>
     5031                        <li><em>Section 6.4.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.31">4.3.1</a>, <a href="#rfc.xref.Part1.47">7.11</a></li>
    50355032                        <li><em>Section 6.5</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.32">4.3.2</a>, <a href="#rfc.xref.Part1.35">4.6.15</a></li>
    50365033                        <li><em>Section 7.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.20">2.3.7</a></li>
    5037                         <li><em>Section 9</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.48">10</a></li>
     5034                        <li><em>Section 9</em>&nbsp;&nbsp;<a href="#rfc.xref.Part1.51">10</a></li>
    50385035                     </ul>
    50395036                  </li>
    … …  
    50885085            </li>
    50895086            <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul>
    5090                   <li>Referer header field&nbsp;&nbsp;<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>
     5087                  <li>Referer header field&nbsp;&nbsp;<a href="#rfc.xref.header.referer.1">3.2</a>, <a href="#rfc.iref.r.1"><b>7.15</b></a>, <a href="#rfc.xref.header.referer.2">8.3</a>, <a href="#rfc.xref.header.referer.3">A</a></li>
    50915088                  <li>representation&nbsp;&nbsp;<a href="#rfc.iref.r.3">D.2</a></li>
    5092                   <li>Retry-After header field&nbsp;&nbsp;<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>
     5089                  <li>Retry-After header field&nbsp;&nbsp;<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>7.16</b></a>, <a href="#rfc.xref.header.retry-after.3">8.3</a></li>
    50935090                  <li><em>RFC1123</em>&nbsp;&nbsp;<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>
    50945091                        <li><em>Section 5.2.14</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1123.2">6.1</a></li>
    50955092                     </ul>
    50965093                  </li>
    5097                   <li><em>RFC1945</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1945.1">4.5</a>, <a href="#RFC1945"><b>11.2</b></a>, <a href="#rfc.xref.RFC1945.2">D.8</a><ul>
     5094                  <li><em>RFC1945</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1945.1">4.5</a>, <a href="#RFC1945"><b>11.2</b></a>, <a href="#rfc.xref.RFC1945.2">D.7</a><ul>
    50985095                        <li><em>Section 9.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC1945.1">4.5</a></li>
    50995096                     </ul>
    51005097                  </li>
    5101                   <li><em>RFC1950</em>&nbsp;&nbsp;<a href="#RFC1950"><b>11.1</b></a>, <a href="#rfc.xref.RFC1950.1">D.5.1</a></li>
    5102                   <li><em>RFC1951</em>&nbsp;&nbsp;<a href="#RFC1951"><b>11.1</b></a>, <a href="#rfc.xref.RFC1951.1">D.5.1</a></li>
    5103                   <li><em>RFC1952</em>&nbsp;&nbsp;<a href="#RFC1952"><b>11.1</b></a>, <a href="#rfc.xref.RFC1952.1">D.5.1</a></li>
    5104                   <li><em>RFC2045</em>&nbsp;&nbsp;<a href="#RFC2045"><b>11.1</b></a>, <a href="#rfc.xref.RFC2045.1">D.7</a>, <a href="#rfc.xref.RFC2045.2">D.7.1</a></li>
    5105                   <li><em>RFC2046</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">6.5</a>, <a href="#rfc.xref.RFC2046.2">6.5.2</a>, <a href="#RFC2046"><b>11.1</b></a>, <a href="#rfc.xref.RFC2046.3">D.2.2</a>, <a href="#rfc.xref.RFC2046.4">D.7.2</a><ul>
     5098                  <li><em>RFC1950</em>&nbsp;&nbsp;<a href="#RFC1950"><b>11.1</b></a>, <a href="#rfc.xref.RFC1950.1">D.4.1</a></li>
     5099                  <li><em>RFC1951</em>&nbsp;&nbsp;<a href="#RFC1951"><b>11.1</b></a>, <a href="#rfc.xref.RFC1951.1">D.4.1</a></li>
     5100                  <li><em>RFC1952</em>&nbsp;&nbsp;<a href="#RFC1952"><b>11.1</b></a>, <a href="#rfc.xref.RFC1952.1">D.4.1</a></li>
     5101                  <li><em>RFC2045</em>&nbsp;&nbsp;<a href="#RFC2045"><b>11.1</b></a>, <a href="#rfc.xref.RFC2045.1">D.6</a>, <a href="#rfc.xref.RFC2045.2">D.6.1</a></li>
     5102                  <li><em>RFC2046</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.1">6.5</a>, <a href="#rfc.xref.RFC2046.2">6.5.2</a>, <a href="#RFC2046"><b>11.1</b></a>, <a href="#rfc.xref.RFC2046.3">D.2.2</a>, <a href="#rfc.xref.RFC2046.4">D.6.2</a><ul>
    51065103                        <li><em>Section 4.5.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.3">D.2.2</a></li>
    51075104                        <li><em>Section 5.1.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2046.2">6.5.2</a></li>
    51085105                     </ul>
    51095106                  </li>
    5110                   <li><em>RFC2049</em>&nbsp;&nbsp;<a href="#RFC2049"><b>11.2</b></a>, <a href="#rfc.xref.RFC2049.1">D.7.2</a><ul>
    5111                         <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2049.1">D.7.2</a></li>
     5107                  <li><em>RFC2049</em>&nbsp;&nbsp;<a href="#RFC2049"><b>11.2</b></a>, <a href="#rfc.xref.RFC2049.1">D.6.2</a><ul>
     5108                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2049.1">D.6.2</a></li>
    51125109                     </ul>
    51135110                  </li>
    5114                   <li><em>RFC2068</em>&nbsp;&nbsp;<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.8</a><ul>
     5111                  <li><em>RFC2068</em>&nbsp;&nbsp;<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.7</a><ul>
    51155112                        <li><em>Section 10.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2068.2">4.5</a></li>
    51165113                        <li><em>Section 10.3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2068.1">4.5</a></li>
    51175114                     </ul>
    51185115                  </li>
    5119                   <li><em>RFC2076</em>&nbsp;&nbsp;<a href="#RFC2076"><b>11.2</b></a>, <a href="#rfc.xref.RFC2076.1">D.8</a></li>
     5116                  <li><em>RFC2076</em>&nbsp;&nbsp;<a href="#RFC2076"><b>11.2</b></a>, <a href="#rfc.xref.RFC2076.1">D.7</a></li>
    51205117                  <li><em>RFC2119</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2119.1">1.2</a>, <a href="#RFC2119"><b>11.1</b></a></li>
    51215118                  <li><em>RFC2277</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2277.1">6.3</a>, <a href="#RFC2277"><b>11.2</b></a></li>
    51225119                  <li><em>RFC2295</em>&nbsp;&nbsp;<a href="#RFC2295"><b>11.2</b></a>, <a href="#rfc.xref.RFC2295.1">D.3</a></li>
    51235120                  <li><em>RFC2388</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2388.1">6.5.2</a>, <a href="#RFC2388"><b>11.2</b></a></li>
    5124                   <li><em>RFC2557</em>&nbsp;&nbsp;<a href="#RFC2557"><b>11.2</b></a>, <a href="#rfc.xref.RFC2557.1">D.4.7</a>, <a href="#rfc.xref.RFC2557.2">D.7.7</a><ul>
    5125                         <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">D.4.7</a></li>
     5121                  <li><em>RFC2557</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">7.8</a>, <a href="#RFC2557"><b>11.2</b></a>, <a href="#rfc.xref.RFC2557.2">D.6.7</a><ul>
     5122                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2557.1">7.8</a></li>
    51265123                     </ul>
    51275124                  </li>
    5128                   <li><em>RFC2616</em>&nbsp;&nbsp;<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.4.4</a>, <a href="#rfc.xref.RFC2616.5">D.10.1</a><ul>
     5125                  <li><em>RFC2616</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.1">1</a>, <a href="#rfc.xref.RFC2616.2">4.5</a>, <a href="#rfc.xref.RFC2616.3">7.4</a>, <a href="#RFC2616"><b>11.2</b></a>, <a href="#rfc.xref.RFC2616.4">C.1</a>, <a href="#rfc.xref.RFC2616.5">D.9.1</a><ul>
    51295126                        <li><em>Section 10.3.8</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.2">4.5</a></li>
    5130                         <li><em>Section 14.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.4">D.4.4</a></li>
     5127                        <li><em>Section 14.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC2616.3">7.4</a></li>
    51315128                     </ul>
    51325129                  </li>
    … …  
    51405137                     </ul>
    51415138                  </li>
    5142                   <li><em>RFC3986</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">7.5</a>, <a href="#rfc.xref.RFC3986.2">7.5</a>, <a href="#RFC3986"><b>11.1</b></a><ul>
    5143                         <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">7.5</a></li>
    5144                         <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.2">7.5</a></li>
     5139                  <li><em>RFC3986</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">7.13</a>, <a href="#rfc.xref.RFC3986.2">7.13</a>, <a href="#RFC3986"><b>11.1</b></a><ul>
     5140                        <li><em>Section 4.2</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.1">7.13</a></li>
     5141                        <li><em>Section 5</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC3986.2">7.13</a></li>
    51455142                     </ul>
    51465143                  </li>
    51475144                  <li><em>RFC4288</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4288.1">6.5</a>, <a href="#RFC4288"><b>11.2</b></a></li>
    5148                   <li><em>RFC4647</em>&nbsp;&nbsp;<a href="#RFC4647"><b>11.1</b></a>, <a href="#rfc.xref.RFC4647.1">D.4.4</a>, <a href="#rfc.xref.RFC4647.2">D.4.4</a>, <a href="#rfc.xref.RFC4647.3">D.4.4</a>, <a href="#rfc.xref.RFC4647.4">D.4.4</a><ul>
    5149                         <li><em>Section 2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">D.4.4</a></li>
    5150                         <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.2">D.4.4</a></li>
    5151                         <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.3">D.4.4</a></li>
    5152                         <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.4">D.4.4</a></li>
     5145                  <li><em>RFC4647</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">7.4</a>, <a href="#rfc.xref.RFC4647.2">7.4</a>, <a href="#rfc.xref.RFC4647.3">7.4</a>, <a href="#rfc.xref.RFC4647.4">7.4</a>, <a href="#RFC4647"><b>11.1</b></a><ul>
     5146                        <li><em>Section 2.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.1">7.4</a></li>
     5147                        <li><em>Section 2.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.2">7.4</a></li>
     5148                        <li><em>Section 3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.3">7.4</a></li>
     5149                        <li><em>Section 3.3.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC4647.4">7.4</a></li>
    51535150                     </ul>
    51545151                  </li>
    … …  
    51615158                     </ul>
    51625159                  </li>
    5163                   <li><em>RFC5322</em>&nbsp;&nbsp;<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.7</a><ul>
     5160                  <li><em>RFC5322</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.1">6.1</a>, <a href="#rfc.xref.RFC5322.2">7.10</a>, <a href="#rfc.xref.RFC5322.3">7.12</a>, <a href="#rfc.xref.RFC5322.4">7.12</a>, <a href="#RFC5322"><b>11.2</b></a>, <a href="#rfc.xref.RFC5322.5">D.6</a><ul>
    51645161                        <li><em>Section 3.3</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.1">6.1</a></li>
    5165                         <li><em>Section 3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.3">7.4</a>, <a href="#rfc.xref.RFC5322.4">7.4</a></li>
    5166                         <li><em>Section 3.6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.2">7.2</a></li>
     5162                        <li><em>Section 3.4</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.3">7.12</a>, <a href="#rfc.xref.RFC5322.4">7.12</a></li>
     5163                        <li><em>Section 3.6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5322.2">7.10</a></li>
    51675164                     </ul>
    51685165                  </li>
    … …  
    51735170                  <li><em>RFC5789</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5789.1">2.3.5</a>, <a href="#RFC5789"><b>11.2</b></a></li>
    51745171                  <li><em>RFC5987</em>&nbsp;&nbsp;<a href="#rfc.xref.RFC5987.1">3.1</a>, <a href="#RFC5987"><b>11.2</b></a></li>
    5175                   <li><em>RFC6151</em>&nbsp;&nbsp;<a href="#RFC6151"><b>11.2</b></a>, <a href="#rfc.xref.RFC6151.1">D.9</a></li>
    5176                   <li><em>RFC6266</em>&nbsp;&nbsp;<a href="#RFC6266"><b>11.2</b></a>, <a href="#rfc.xref.RFC6266.1">D.8</a>, <a href="#rfc.xref.RFC6266.2">D.9</a></li>
     5172                  <li><em>RFC6151</em>&nbsp;&nbsp;<a href="#RFC6151"><b>11.2</b></a>, <a href="#rfc.xref.RFC6151.1">D.8</a></li>
     5173                  <li><em>RFC6266</em>&nbsp;&nbsp;<a href="#RFC6266"><b>11.2</b></a>, <a href="#rfc.xref.RFC6266.1">D.7</a>, <a href="#rfc.xref.RFC6266.2">D.8</a></li>
    51775174               </ul>
    51785175            </li>
    … …  
    51805177                  <li>Safe Methods&nbsp;&nbsp;<a href="#rfc.iref.s.2"><b>2.1.1</b></a></li>
    51815178                  <li>selected representation&nbsp;&nbsp;<a href="#rfc.iref.s.1"><b>1.1</b></a></li>
    5182                   <li>Server header field&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">3.3</a>, <a href="#rfc.iref.s.39"><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>
     5179                  <li>Server header field&nbsp;&nbsp;<a href="#rfc.xref.header.server.1">3.3</a>, <a href="#rfc.iref.s.39"><b>7.17</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>
    51835180                  <li>Status Codes&nbsp;&nbsp;
    51845181                     <ul>
    … …  
    52245221            </li>
    52255222            <li><a id="rfc.index.T" href="#rfc.index.T"><b>T</b></a><ul>
    5226                   <li>TRACE method&nbsp;&nbsp;<a href="#rfc.iref.t.1"><b>2.3.7</b></a>, <a href="#rfc.xref.TRACE.1">7.6</a>, <a href="#rfc.xref.TRACE.2">8.1</a>, <a href="#rfc.xref.TRACE.3">9.1</a></li>
     5223                  <li>TRACE method&nbsp;&nbsp;<a href="#rfc.iref.t.1"><b>2.3.7</b></a>, <a href="#rfc.xref.TRACE.1">7.14</a>, <a href="#rfc.xref.TRACE.2">8.1</a>, <a href="#rfc.xref.TRACE.3">9.1</a></li>
    52275224               </ul>
    52285225            </li>
    52295226            <li><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul>
    5230                   <li>User-Agent header field&nbsp;&nbsp;<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.3.1</a></li>
     5227                  <li>User-Agent header field&nbsp;&nbsp;<a href="#rfc.xref.header.user-agent.1">3.2</a>, <a href="#rfc.iref.u.1"><b>7.18</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.3.1</a></li>
    52315228               </ul>
    52325229            </li>

  • draft-ietf-httpbis/latest/p2-semantics.xml

    r1644 r1645  
    26052605<t>
    26062606   This section defines the syntax and semantics of HTTP/1.1 header fields
    2607    related to request and response semantics.
    2608 </t>
     2607   related to request and response semantics and to the payload of messages.
     2608</t>
     2609
     2610
     2611<section title="Accept" anchor="header.accept">
     2612  <iref primary="true" item="Accept header field" x:for-anchor=""/>
     2613  <iref primary="true" item="Header Fields" subitem="Accept" x:for-anchor=""/>
     2614  <x:anchor-alias value="Accept"/>
     2615  <x:anchor-alias value="accept-ext"/>
     2616  <x:anchor-alias value="accept-params"/>
     2617  <x:anchor-alias value="media-range"/>
     2618<t>
     2619   The "Accept" header field can be used by user agents to specify
     2620   response media types that are acceptable. Accept header fields can be used to
     2621   indicate that the request is specifically limited to a small set of desired
     2622   types, as in the case of a request for an in-line image.
     2623</t>
     2624<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"/>
     2625  <x:ref>Accept</x:ref> = #( <x:ref>media-range</x:ref> [ <x:ref>accept-params</x:ref> ] )
     2626 
     2627  <x:ref>media-range</x:ref>    = ( "*/*"
     2628                   / ( <x:ref>type</x:ref> "/" "*" )
     2629                   / ( <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> )
     2630                   ) *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> )
     2631  <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> )
     2632  <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> ]
     2633</artwork></figure>
     2634<t>
     2635   The asterisk "*" character is used to group media types into ranges,
     2636   with "*/*" indicating all media types and "type/*" indicating all
     2637   subtypes of that type. The media-range &MAY; include media type
     2638   parameters that are applicable to that range.
     2639</t>
     2640<t>
     2641   Each media-range &MAY; be followed by one or more accept-params,
     2642   beginning with the "q" parameter for indicating a relative quality
     2643   factor. The first "q" parameter (if any) separates the media-range
     2644   parameter(s) from the accept-params. Quality factors allow the user
     2645   or user agent to indicate the relative degree of preference for that
     2646   media-range, using the qvalue scale from 0 to 1 (&qvalue;). The
     2647   default value is q=1.
     2648</t>
     2649<x:note>
     2650  <t>
     2651    <x:h>Note:</x:h> Use of the "q" parameter name to separate media type
     2652    parameters from Accept extension parameters is due to historical
     2653    practice. Although this prevents any media type parameter named
     2654    "q" from being used with a media range, such an event is believed
     2655    to be unlikely given the lack of any "q" parameters in the IANA
     2656    media type registry and the rare usage of any media type
     2657    parameters in Accept. Future media types are discouraged from
     2658    registering any parameter named "q".
     2659  </t>
     2660</x:note>
     2661<t>
     2662   The example
     2663</t>
     2664<figure><artwork type="example">
     2665  Accept: audio/*; q=0.2, audio/basic
     2666</artwork></figure>
     2667<t>
     2668   &SHOULD; be interpreted as "I prefer audio/basic, but send me any audio
     2669   type if it is the best available after an 80% mark-down in quality".
     2670</t>
     2671<t>
     2672   A request without any Accept header field implies that the user agent
     2673   will accept any media type in response.
     2674   If an Accept header field is present in a request and none of the
     2675   available representations for the response have a media type that is
     2676   listed as acceptable, the origin server &MAY; either
     2677   honor the Accept header field by sending a 406 (Not Acceptable) response
     2678   or disregard the Accept header field by treating the response as if
     2679   it is not subject to content negotiation.
     2680</t>
     2681<t>
     2682   A more elaborate example is
     2683</t>
     2684<figure><artwork type="example">
     2685  Accept: text/plain; q=0.5, text/html,
     2686          text/x-dvi; q=0.8, text/x-c
     2687</artwork></figure>
     2688<t>
     2689   Verbally, this would be interpreted as "text/html and text/x-c are
     2690   the preferred media types, but if they do not exist, then send the
     2691   text/x-dvi representation, and if that does not exist, send the text/plain
     2692   representation".
     2693</t>
     2694<t>
     2695   Media ranges can be overridden by more specific media ranges or
     2696   specific media types. If more than one media range applies to a given
     2697   type, the most specific reference has precedence. For example,
     2698</t>
     2699<figure><artwork type="example">
     2700  Accept: text/*, text/plain, text/plain;format=flowed, */*
     2701</artwork></figure>
     2702<t>
     2703   have the following precedence:
     2704   <list style="numbers">
     2705    <t>text/plain;format=flowed</t>
     2706    <t>text/plain</t>
     2707    <t>text/*</t>
     2708    <t>*/*</t>
     2709   </list>
     2710</t>
     2711<t>
     2712   The media type quality factor associated with a given type is
     2713   determined by finding the media range with the highest precedence
     2714   which matches that type. For example,
     2715</t>
     2716<figure><artwork type="example">
     2717  Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
     2718          text/html;level=2;q=0.4, */*;q=0.5
     2719</artwork></figure>
     2720<t>
     2721   would cause the following values to be associated:
     2722</t>
     2723<texttable align="left">
     2724  <ttcol>Media Type</ttcol><ttcol>Quality Value</ttcol>
     2725  <c>text/html;level=1</c>    <c>1</c>
     2726  <c>text/html</c>            <c>0.7</c>
     2727  <c>text/plain</c>           <c>0.3</c>
     2728  <c>image/jpeg</c>           <c>0.5</c>
     2729  <c>text/html;level=2</c>    <c>0.4</c>
     2730  <c>text/html;level=3</c>    <c>0.7</c>
     2731</texttable>
     2732<t>
     2733      <x:h>Note:</x:h> A user agent might be provided with a default set of quality
     2734      values for certain media ranges. However, unless the user agent is
     2735      a closed system which cannot interact with other rendering agents,
     2736      this default set ought to be configurable by the user.
     2737</t>
     2738</section>
     2739
     2740<section title="Accept-Charset" anchor="header.accept-charset">
     2741  <iref primary="true" item="Accept-Charset header field" x:for-anchor=""/>
     2742  <iref primary="true" item="Header Fields" subitem="Accept-Charset" x:for-anchor=""/>
     2743  <x:anchor-alias value="Accept-Charset"/>
     2744<t>
     2745   The "Accept-Charset" header field can be used by user agents to
     2746   indicate what character encodings are acceptable in a response
     2747   payload. This field allows
     2748   clients capable of understanding more comprehensive or special-purpose
     2749   character encodings to signal that capability to a server which is capable of
     2750   representing documents in those character encodings.
     2751</t>
     2752<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Charset"/>
     2753  <x:ref>Accept-Charset</x:ref> = 1#( ( <x:ref>charset</x:ref> / "*" )
     2754                         [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
     2755</artwork></figure>
     2756<t>
     2757   Character encoding values (a.k.a., charsets) are described in
     2758   <xref target="character.sets"/>. Each charset &MAY; be given an
     2759   associated quality value which represents the user's preference
     2760   for that charset. The default value is q=1. An example is
     2761</t>
     2762<figure><artwork type="example">
     2763  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
     2764</artwork></figure>
     2765<t>
     2766   The special value "*", if present in the Accept-Charset field,
     2767   matches every character encoding which is not mentioned elsewhere in the
     2768   Accept-Charset field. If no "*" is present in an Accept-Charset field, then
     2769   all character encodings not explicitly mentioned get a quality value of 0.
     2770</t>
     2771<t>
     2772   A request without any Accept-Charset header field implies that the user
     2773   agent will accept any character encoding in response.
     2774   If an Accept-Charset header field is present in a request and none of the
     2775   available representations for the response have a character encoding that
     2776   is listed as acceptable, the origin server &MAY; either honor the
     2777   Accept-Charset header field by sending a 406 (Not Acceptable) response or
     2778   disregard the Accept-Charset header field by treating the response as if
     2779   it is not subject to content negotiation.
     2780</t>
     2781</section>
     2782
     2783<section title="Accept-Encoding" anchor="header.accept-encoding">
     2784  <iref primary="true" item="Accept-Encoding header field" x:for-anchor=""/>
     2785  <iref primary="true" item="Header Fields" subitem="Accept-Encoding" x:for-anchor=""/>
     2786  <x:anchor-alias value="Accept-Encoding"/>
     2787  <x:anchor-alias value="codings"/>
     2788<t>
     2789   The "Accept-Encoding" header field can be used by user agents to
     2790   indicate what response content-codings (<xref target="content.codings"/>)
     2791   are acceptable in the response.  An "identity" token is used as a synonym
     2792   for "no encoding" in order to communicate when no encoding is preferred.
     2793</t>
     2794<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Encoding"/><iref primary="true" item="Grammar" subitem="codings"/>
     2795  <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> ] )
     2796  <x:ref>codings</x:ref>          = <x:ref>content-coding</x:ref> / "identity" / "*"
     2797</artwork></figure>
     2798<t>
     2799   Each codings value &MAY; be given an associated quality value which
     2800   represents the preference for that encoding. The default value is q=1.
     2801</t>
     2802<t>
     2803   For example,
     2804</t>
     2805<figure><artwork type="example">
     2806  Accept-Encoding: compress, gzip
     2807  Accept-Encoding:
     2808  Accept-Encoding: *
     2809  Accept-Encoding: compress;q=0.5, gzip;q=1.0
     2810  Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
     2811</artwork></figure>
     2812<t>
     2813   A server tests whether a content-coding for a given representation is
     2814   acceptable, according to an Accept-Encoding field, using these rules:
     2815  <list style="numbers">
     2816      <t>The special "*" symbol in an Accept-Encoding field matches any
     2817         available content-coding not explicitly listed in the header
     2818         field.</t>
     2819
     2820      <t>If the representation has no content-coding, then it is acceptable
     2821         by default unless specifically excluded by the Accept-Encoding field
     2822         stating either "identity;q=0" or "*;q=0" without a more specific
     2823         entry for "identity".</t>
     2824
     2825      <t>If the representation's content-coding is one of the content-codings
     2826         listed in the Accept-Encoding field, then it is acceptable unless
     2827         it is accompanied by a qvalue of 0. (As defined in &qvalue;, a
     2828         qvalue of 0 means "not acceptable".)</t>
     2829
     2830      <t>If multiple content-codings are acceptable, then the acceptable
     2831         content-coding with the highest non-zero qvalue is preferred.</t>
     2832  </list>
     2833</t>
     2834<t>
     2835   An Accept-Encoding header field with a combined field-value that is empty
     2836   implies that the user agent does not want any content-coding in response.
     2837   If an Accept-Encoding header field is present in a request and none of the
     2838   available representations for the response have a content-coding that
     2839   is listed as acceptable, the origin server &SHOULD; send a response
     2840   without any content-coding.
     2841</t>
     2842<t>
     2843   A request without an Accept-Encoding header field implies that the user
     2844   agent will accept any content-coding in response, but a representation
     2845   without content-coding is preferred for compatibility with the widest
     2846   variety of user agents.
     2847</t>
     2848<x:note>
     2849  <t>
     2850    <x:h>Note:</x:h> Most HTTP/1.0 applications do not recognize or obey qvalues
     2851    associated with content-codings. This means that qvalues will not
     2852    work and are not permitted with x-gzip or x-compress.
     2853  </t>
     2854</x:note>
     2855</section>
     2856
     2857<section title="Accept-Language" anchor="header.accept-language">
     2858  <iref primary="true" item="Accept-Language header field" x:for-anchor=""/>
     2859  <iref primary="true" item="Header Fields" subitem="Accept-Language" x:for-anchor=""/>
     2860  <x:anchor-alias value="Accept-Language"/>
     2861  <x:anchor-alias value="language-range"/>
     2862<t>
     2863   The "Accept-Language" header field can be used by user agents to
     2864   indicate the set of natural languages that are preferred in the response.
     2865   Language tags are defined in <xref target="language.tags"/>.
     2866</t>
     2867<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Language"/><iref primary="true" item="Grammar" subitem="language-range"/>
     2868  <x:ref>Accept-Language</x:ref> =
     2869                    1#( <x:ref>language-range</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
     2870  <x:ref>language-range</x:ref>  =
     2871            &lt;language-range, defined in <xref target="RFC4647" x:fmt="," x:sec="2.1"/>&gt;
     2872</artwork></figure>
     2873<t>
     2874   Each language-range can be given an associated quality value which
     2875   represents an estimate of the user's preference for the languages
     2876   specified by that range. The quality value defaults to "q=1". For
     2877   example,
     2878</t>
     2879<figure><artwork type="example">
     2880  Accept-Language: da, en-gb;q=0.8, en;q=0.7
     2881</artwork></figure>
     2882<t>
     2883   would mean: "I prefer Danish, but will accept British English and
     2884   other types of English".
     2885   (see also <xref target="RFC4647" x:sec="2.3" x:fmt="of"/>)
     2886</t>
     2887<t>
     2888   For matching, <xref target="RFC4647" x:sec="3" x:fmt="of"/> defines
     2889   several matching schemes. Implementations can offer the most appropriate
     2890   matching scheme for their requirements.
     2891</t>
     2892<x:note>
     2893  <t>
     2894    <x:h>Note:</x:h> The "Basic Filtering" scheme (<xref target="RFC4647"
     2895    x:fmt="," x:sec="3.3.1"/>) is identical to the matching scheme that was
     2896    previously defined in <xref target="RFC2616" x:fmt="of" x:sec="14.4"/>.
     2897  </t>
     2898</x:note>
     2899<t>
     2900   It might be contrary to the privacy expectations of the user to send
     2901   an Accept-Language header field with the complete linguistic preferences of
     2902   the user in every request. For a discussion of this issue, see
     2903   <xref target="privacy.issues.connected.to.accept.header.fields"/>.
     2904</t>
     2905<t>
     2906   As intelligibility is highly dependent on the individual user, it is
     2907   recommended that client applications make the choice of linguistic
     2908   preference available to the user. If the choice is not made
     2909   available, then the Accept-Language header field &MUST-NOT; be given in
     2910   the request.
     2911</t>
     2912<x:note>
     2913  <t>
     2914    <x:h>Note:</x:h> When making the choice of linguistic preference available to
     2915    the user, we remind implementors of  the fact that users are not
     2916    familiar with the details of language matching as described above,
     2917    and ought to be provided appropriate guidance. As an example, users
     2918    might assume that on selecting "en-gb", they will be served any
     2919    kind of English document if British English is not available. A
     2920    user agent might suggest in such a case to add "en" to get the
     2921    best matching behavior.
     2922  </t>
     2923</x:note>
     2924</section>
    26092925
    26102926<section title="Allow" anchor="header.allow">
    … …  
    26342950   understand all the methods specified in order to handle them according to
    26352951   the generic message handling rules.
     2952</t>
     2953</section>
     2954
     2955
     2956<section title="Content-Encoding" anchor="header.content-encoding">
     2957  <iref primary="true" item="Content-Encoding header field" x:for-anchor=""/>
     2958  <iref primary="true" item="Header Fields" subitem="Content-Encoding" x:for-anchor=""/>
     2959  <x:anchor-alias value="Content-Encoding"/>
     2960<t>
     2961   The "Content-Encoding" header field indicates what content-codings
     2962   have been applied to the representation beyond those inherent in the media
     2963   type, and thus what decoding mechanisms have to be applied in order to obtain
     2964   the media-type referenced by the Content-Type header field.
     2965   Content-Encoding is primarily used to allow a representation to be
     2966   compressed without losing the identity of its underlying media type.
     2967</t>
     2968<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Encoding"/>
     2969  <x:ref>Content-Encoding</x:ref> = 1#<x:ref>content-coding</x:ref>
     2970</artwork></figure>
     2971<t>
     2972   Content codings are defined in <xref target="content.codings"/>. An example of its use is
     2973</t>
     2974<figure><artwork type="example">
     2975  Content-Encoding: gzip
     2976</artwork></figure>
     2977<t>
     2978   The content-coding is a characteristic of the representation.
     2979   Typically, the representation body is stored with this
     2980   encoding and is only decoded before rendering or analogous usage.
     2981   However, a transforming proxy &MAY; modify the content-coding if the
     2982   new coding is known to be acceptable to the recipient, unless the
     2983   "no-transform" cache-control directive is present in the message.
     2984</t>
     2985<t>
     2986   If the media type includes an inherent encoding, such as a data format
     2987   that is always compressed, then that encoding would not be restated as
     2988   a Content-Encoding even if it happens to be the same algorithm as one
     2989   of the content-codings.  Such a content-coding would only be listed if,
     2990   for some bizarre reason, it is applied a second time to form the
     2991   representation.  Likewise, an origin server might choose to publish the
     2992   same payload data as multiple representations that differ only in whether
     2993   the coding is defined as part of Content-Type or Content-Encoding, since
     2994   some user agents will behave differently in their handling of each
     2995   response (e.g., open a "Save as ..." dialog instead of automatic
     2996   decompression and rendering of content).
     2997</t>
     2998<t>
     2999   A representation that has a content-coding applied to it &MUST; include
     3000   a Content-Encoding header field (<xref target="header.content-encoding"/>)
     3001   that lists the content-coding(s) applied.
     3002</t>
     3003<t>
     3004   If multiple encodings have been applied to a representation, the content
     3005   codings &MUST; be listed in the order in which they were applied.
     3006   Additional information about the encoding parameters &MAY; be provided
     3007   by other header fields not defined by this specification.
     3008</t>
     3009<t>
     3010   If the content-coding of a representation in a request message is not
     3011   acceptable to the origin server, the server &SHOULD; respond with a
     3012   status code of 415 (Unsupported Media Type).
     3013</t>
     3014</section>
     3015
     3016<section title="Content-Language" anchor="header.content-language">
     3017  <iref primary="true" item="Content-Language header field" x:for-anchor=""/>
     3018  <iref primary="true" item="Header Fields" subitem="Content-Language" x:for-anchor=""/>
     3019  <x:anchor-alias value="Content-Language"/>
     3020<t>
     3021   The "Content-Language" header field describes the natural
     3022   language(s) of the intended audience for the representation. Note that this might
     3023   not be equivalent to all the languages used within the representation.
     3024</t>
     3025<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Language"/>
     3026  <x:ref>Content-Language</x:ref> = 1#<x:ref>language-tag</x:ref>
     3027</artwork></figure>
     3028<t>
     3029   Language tags are defined in <xref target="language.tags"/>. The primary purpose of
     3030   Content-Language is to allow a user to identify and differentiate
     3031   representations according to the user's own preferred language. Thus, if the
     3032   body content is intended only for a Danish-literate audience, the
     3033   appropriate field is
     3034</t>
     3035<figure><artwork type="example">
     3036  Content-Language: da
     3037</artwork></figure>
     3038<t>
     3039   If no Content-Language is specified, the default is that the content
     3040   is intended for all language audiences. This might mean that the
     3041   sender does not consider it to be specific to any natural language,
     3042   or that the sender does not know for which language it is intended.
     3043</t>
     3044<t>
     3045   Multiple languages &MAY; be listed for content that is intended for
     3046   multiple audiences. For example, a rendition of the "Treaty of
     3047   Waitangi", presented simultaneously in the original Maori and English
     3048   versions, would call for
     3049</t>
     3050<figure><artwork type="example">
     3051  Content-Language: mi, en
     3052</artwork></figure>
     3053<t>
     3054   However, just because multiple languages are present within a representation
     3055   does not mean that it is intended for multiple linguistic audiences.
     3056   An example would be a beginner's language primer, such as "A First
     3057   Lesson in Latin", which is clearly intended to be used by an
     3058   English-literate audience. In this case, the Content-Language would
     3059   properly only include "en".
     3060</t>
     3061<t>
     3062   Content-Language &MAY; be applied to any media type &mdash; it is not
     3063   limited to textual documents.
     3064</t>
     3065</section>
     3066
     3067<section title="Content-Location" anchor="header.content-location">
     3068  <iref primary="true" item="Content-Location header field" x:for-anchor=""/>
     3069  <iref primary="true" item="Header Fields" subitem="Content-Location" x:for-anchor=""/>
     3070  <x:anchor-alias value="Content-Location"/>
     3071<t>
     3072   The "Content-Location" header field supplies a URI that can be used
     3073   as a specific identifier for the representation in this message.
     3074   In other words, if one were to perform a GET on this URI at the time
     3075   of this message's generation, then a 200 response would contain the
     3076   same representation that is enclosed as payload in this message.
     3077</t>
     3078<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Location"/>
     3079  <x:ref>Content-Location</x:ref> = <x:ref>absolute-URI</x:ref> / <x:ref>partial-URI</x:ref>
     3080</artwork></figure>
     3081<t>
     3082   The Content-Location value is not a replacement for the effective
     3083   Request URI (&effective-request-uri;).  It is representation metadata.
     3084   It has the same syntax and semantics as the header field of the same name
     3085   defined for MIME body parts in <xref target="RFC2557" x:fmt="of" x:sec="4"/>.
     3086   However, its appearance in an HTTP message has some special implications
     3087   for HTTP recipients.
     3088</t>
     3089<t>
     3090   If Content-Location is included in a response message and its value
     3091   is the same as the effective request URI, then the response payload
     3092   &SHOULD; be considered a current representation of that resource.
     3093   For a GET or HEAD request, this is the same as the default semantics
     3094   when no Content-Location is provided by the server.  For a state-changing
     3095   request like PUT or POST, it implies that the server's response contains
     3096   the new representation of that resource, thereby distinguishing it from
     3097   representations that might only report about the action (e.g., "It worked!").
     3098   This allows authoring applications to update their local copies without
     3099   the need for a subsequent GET request.
     3100</t>
     3101<t>
     3102   If Content-Location is included in a response message and its value
     3103   differs from the effective request URI, then the origin server is
     3104   informing recipients that this representation has its own, presumably
     3105   more specific, identifier.  For a GET or HEAD request, this is an
     3106   indication that the effective request URI identifies a resource that
     3107   is subject to content negotiation and the selected representation for
     3108   this response can also be found at the identified URI.  For other
     3109   methods, such a Content-Location indicates that this representation
     3110   contains a report on the action's status and the same report is
     3111   available (for future access with GET) at the given URI.  For
     3112   example, a purchase transaction made via a POST request might
     3113   include a receipt document as the payload of the 200 response;
     3114   the Content-Location value provides an identifier for retrieving
     3115   a copy of that same receipt in the future.
     3116</t>
     3117<t>
     3118   If Content-Location is included in a request message, then it &MAY;
     3119   be interpreted by the origin server as an indication of where the
     3120   user agent originally obtained the content of the enclosed
     3121   representation (prior to any subsequent modification of the content
     3122   by that user agent).  In other words, the user agent is providing
     3123   the same representation metadata that it received with the original
     3124   representation.  However, such interpretation &MUST-NOT; be used to
     3125   alter the semantics of the method requested by the client.  For
     3126   example, if a client makes a PUT request on a negotiated resource
     3127   and the origin server accepts that PUT (without redirection), then the
     3128   new set of values for that resource is expected to be consistent with
     3129   the one representation supplied in that PUT; the Content-Location
     3130   cannot be used as a form of reverse content selection that
     3131   identifies only one of the negotiated representations to be updated.
     3132   If the user agent had wanted the latter semantics, it would have applied
     3133   the PUT directly to the Content-Location URI.
     3134</t>
     3135<t>
     3136   A Content-Location field received in a request message is transitory
     3137   information that &SHOULD-NOT; be saved with other representation
     3138   metadata for use in later responses.  The Content-Location's value
     3139   might be saved for use in other contexts, such as within source links
     3140   or other metadata.
     3141</t>
     3142<t>
     3143   A cache cannot assume that a representation with a Content-Location
     3144   different from the URI used to retrieve it can be used to respond to
     3145   later requests on that Content-Location URI.
     3146</t>
     3147<t>
     3148   If the Content-Location value is a partial URI, the partial URI is
     3149   interpreted relative to the effective request URI.
     3150</t>
     3151</section>
     3152
     3153<section title="Content-Type" anchor="header.content-type">
     3154  <iref primary="true" item="Content-Type header field" x:for-anchor=""/>
     3155  <iref primary="true" item="Header Fields" subitem="Content-Type" x:for-anchor=""/>
     3156  <x:anchor-alias value="Content-Type"/>
     3157<t>
     3158   The "Content-Type" header field indicates the media type of the
     3159   representation. In the case of responses to the HEAD method, the media type is
     3160   that which would have been sent had the request been a GET.
     3161</t>
     3162<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Type"/>
     3163  <x:ref>Content-Type</x:ref> = <x:ref>media-type</x:ref>
     3164</artwork></figure>
     3165<t>
     3166   Media types are defined in <xref target="media.types"/>. An example of the field is
     3167</t>
     3168<figure><artwork type="example">
     3169  Content-Type: text/html; charset=ISO-8859-4
     3170</artwork></figure>
     3171<t>
     3172   Further discussion of Content-Type is provided in <xref target="representation.data"/>.
    26363173</t>
    26373174</section>
    … …  
    30613598</artwork></figure>
    30623599</section>
    3063 
    30643600</section>
    30653601
    … …  
    55106046</section>
    55116047
    5512 <section title="Header Field Definitions" anchor="header.field.definitions3">
    5513 <t>
    5514    This section defines the syntax and semantics of HTTP/1.1 header fields
    5515    related to the payload of messages.
    5516 </t>
    5517 
    5518 <section title="Accept" anchor="header.accept">
    5519   <iref primary="true" item="Accept header field" x:for-anchor=""/>
    5520   <iref primary="true" item="Header Fields" subitem="Accept" x:for-anchor=""/>
    5521   <x:anchor-alias value="Accept"/>
    5522   <x:anchor-alias value="accept-ext"/>
    5523   <x:anchor-alias value="accept-params"/>
    5524   <x:anchor-alias value="media-range"/>
    5525 <t>
    5526    The "Accept" header field can be used by user agents to specify
    5527    response media types that are acceptable. Accept header fields can be used to
    5528    indicate that the request is specifically limited to a small set of desired
    5529    types, as in the case of a request for an in-line image.
    5530 </t>
    5531 <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"/>
    5532   <x:ref>Accept</x:ref> = #( <x:ref>media-range</x:ref> [ <x:ref>accept-params</x:ref> ] )
    5533  
    5534   <x:ref>media-range</x:ref>    = ( "*/*"
    5535                    / ( <x:ref>type</x:ref> "/" "*" )
    5536                    / ( <x:ref>type</x:ref> "/" <x:ref>subtype</x:ref> )
    5537                    ) *( <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> <x:ref>parameter</x:ref> )
    5538   <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> )
    5539   <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> ]
    5540 </artwork></figure>
    5541 <t>
    5542    The asterisk "*" character is used to group media types into ranges,
    5543    with "*/*" indicating all media types and "type/*" indicating all
    5544    subtypes of that type. The media-range &MAY; include media type
    5545    parameters that are applicable to that range.
    5546 </t>
    5547 <t>
    5548    Each media-range &MAY; be followed by one or more accept-params,
    5549    beginning with the "q" parameter for indicating a relative quality
    5550    factor. The first "q" parameter (if any) separates the media-range
    5551    parameter(s) from the accept-params. Quality factors allow the user
    5552    or user agent to indicate the relative degree of preference for that
    5553    media-range, using the qvalue scale from 0 to 1 (&qvalue;). The
    5554    default value is q=1.
    5555 </t>
    5556 <x:note>
    5557   <t>
    5558     <x:h>Note:</x:h> Use of the "q" parameter name to separate media type
    5559     parameters from Accept extension parameters is due to historical
    5560     practice. Although this prevents any media type parameter named
    5561     "q" from being used with a media range, such an event is believed
    5562     to be unlikely given the lack of any "q" parameters in the IANA
    5563     media type registry and the rare usage of any media type
    5564     parameters in Accept. Future media types are discouraged from
    5565     registering any parameter named "q".
    5566   </t>
    5567 </x:note>
    5568 <t>
    5569    The example
    5570 </t>
    5571 <figure><artwork type="example">
    5572   Accept: audio/*; q=0.2, audio/basic
    5573 </artwork></figure>
    5574 <t>
    5575    &SHOULD; be interpreted as "I prefer audio/basic, but send me any audio
    5576    type if it is the best available after an 80% mark-down in quality".
    5577 </t>
    5578 <t>
    5579    A request without any Accept header field implies that the user agent
    5580    will accept any media type in response.
    5581    If an Accept header field is present in a request and none of the
    5582    available representations for the response have a media type that is
    5583    listed as acceptable, the origin server &MAY; either
    5584    honor the Accept header field by sending a 406 (Not Acceptable) response
    5585    or disregard the Accept header field by treating the response as if
    5586    it is not subject to content negotiation.
    5587 </t>
    5588 <t>
    5589    A more elaborate example is
    5590 </t>
    5591 <figure><artwork type="example">
    5592   Accept: text/plain; q=0.5, text/html,
    5593           text/x-dvi; q=0.8, text/x-c
    5594 </artwork></figure>
    5595 <t>
    5596    Verbally, this would be interpreted as "text/html and text/x-c are
    5597    the preferred media types, but if they do not exist, then send the
    5598    text/x-dvi representation, and if that does not exist, send the text/plain
    5599    representation".
    5600 </t>
    5601 <t>
    5602    Media ranges can be overridden by more specific media ranges or
    5603    specific media types. If more than one media range applies to a given
    5604    type, the most specific reference has precedence. For example,
    5605 </t>
    5606 <figure><artwork type="example">
    5607   Accept: text/*, text/plain, text/plain;format=flowed, */*
    5608 </artwork></figure>
    5609 <t>
    5610    have the following precedence:
    5611    <list style="numbers">
    5612     <t>text/plain;format=flowed</t>
    5613     <t>text/plain</t>
    5614     <t>text/*</t>
    5615     <t>*/*</t>
    5616    </list>
    5617 </t>
    5618 <t>
    5619    The media type quality factor associated with a given type is
    5620    determined by finding the media range with the highest precedence
    5621    which matches that type. For example,
    5622 </t>
    5623 <figure><artwork type="example">
    5624   Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,
    5625           text/html;level=2;q=0.4, */*;q=0.5
    5626 </artwork></figure>
    5627 <t>
    5628    would cause the following values to be associated:
    5629 </t>
    5630 <texttable align="left">
    5631   <ttcol>Media Type</ttcol><ttcol>Quality Value</ttcol>
    5632   <c>text/html;level=1</c>    <c>1</c>
    5633   <c>text/html</c>            <c>0.7</c>
    5634   <c>text/plain</c>           <c>0.3</c>
    5635   <c>image/jpeg</c>           <c>0.5</c>
    5636   <c>text/html;level=2</c>    <c>0.4</c>
    5637   <c>text/html;level=3</c>    <c>0.7</c>
    5638 </texttable>
    5639 <t>
    5640       <x:h>Note:</x:h> A user agent might be provided with a default set of quality
    5641       values for certain media ranges. However, unless the user agent is
    5642       a closed system which cannot interact with other rendering agents,
    5643       this default set ought to be configurable by the user.
    5644 </t>
    5645 </section>
    5646 
    5647 <section title="Accept-Charset" anchor="header.accept-charset">
    5648   <iref primary="true" item="Accept-Charset header field" x:for-anchor=""/>
    5649   <iref primary="true" item="Header Fields" subitem="Accept-Charset" x:for-anchor=""/>
    5650   <x:anchor-alias value="Accept-Charset"/>
    5651 <t>
    5652    The "Accept-Charset" header field can be used by user agents to
    5653    indicate what character encodings are acceptable in a response
    5654    payload. This field allows
    5655    clients capable of understanding more comprehensive or special-purpose
    5656    character encodings to signal that capability to a server which is capable of
    5657    representing documents in those character encodings.
    5658 </t>
    5659 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Charset"/>
    5660   <x:ref>Accept-Charset</x:ref> = 1#( ( <x:ref>charset</x:ref> / "*" )
    5661                          [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
    5662 </artwork></figure>
    5663 <t>
    5664    Character encoding values (a.k.a., charsets) are described in
    5665    <xref target="character.sets"/>. Each charset &MAY; be given an
    5666    associated quality value which represents the user's preference
    5667    for that charset. The default value is q=1. An example is
    5668 </t>
    5669 <figure><artwork type="example">
    5670   Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
    5671 </artwork></figure>
    5672 <t>
    5673    The special value "*", if present in the Accept-Charset field,
    5674    matches every character encoding which is not mentioned elsewhere in the
    5675    Accept-Charset field. If no "*" is present in an Accept-Charset field, then
    5676    all character encodings not explicitly mentioned get a quality value of 0.
    5677 </t>
    5678 <t>
    5679    A request without any Accept-Charset header field implies that the user
    5680    agent will accept any character encoding in response.
    5681    If an Accept-Charset header field is present in a request and none of the
    5682    available representations for the response have a character encoding that
    5683    is listed as acceptable, the origin server &MAY; either honor the
    5684    Accept-Charset header field by sending a 406 (Not Acceptable) response or
    5685    disregard the Accept-Charset header field by treating the response as if
    5686    it is not subject to content negotiation.
    5687 </t>
    5688 </section>
    5689 
    5690 <section title="Accept-Encoding" anchor="header.accept-encoding">
    5691   <iref primary="true" item="Accept-Encoding header field" x:for-anchor=""/>
    5692   <iref primary="true" item="Header Fields" subitem="Accept-Encoding" x:for-anchor=""/>
    5693   <x:anchor-alias value="Accept-Encoding"/>
    5694   <x:anchor-alias value="codings"/>
    5695 <t>
    5696    The "Accept-Encoding" header field can be used by user agents to
    5697    indicate what response content-codings (<xref target="content.codings"/>)
    5698    are acceptable in the response.  An "identity" token is used as a synonym
    5699    for "no encoding" in order to communicate when no encoding is preferred.
    5700 </t>
    5701 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Encoding"/><iref primary="true" item="Grammar" subitem="codings"/>
    5702   <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> ] )
    5703   <x:ref>codings</x:ref>          = <x:ref>content-coding</x:ref> / "identity" / "*"
    5704 </artwork></figure>
    5705 <t>
    5706    Each codings value &MAY; be given an associated quality value which
    5707    represents the preference for that encoding. The default value is q=1.
    5708 </t>
    5709 <t>
    5710    For example,
    5711 </t>
    5712 <figure><artwork type="example">
    5713   Accept-Encoding: compress, gzip
    5714   Accept-Encoding:
    5715   Accept-Encoding: *
    5716   Accept-Encoding: compress;q=0.5, gzip;q=1.0
    5717   Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0
    5718 </artwork></figure>
    5719 <t>
    5720    A server tests whether a content-coding for a given representation is
    5721    acceptable, according to an Accept-Encoding field, using these rules:
    5722   <list style="numbers">
    5723       <t>The special "*" symbol in an Accept-Encoding field matches any
    5724          available content-coding not explicitly listed in the header
    5725          field.</t>
    5726 
    5727       <t>If the representation has no content-coding, then it is acceptable
    5728          by default unless specifically excluded by the Accept-Encoding field
    5729          stating either "identity;q=0" or "*;q=0" without a more specific
    5730          entry for "identity".</t>
    5731 
    5732       <t>If the representation's content-coding is one of the content-codings
    5733          listed in the Accept-Encoding field, then it is acceptable unless
    5734          it is accompanied by a qvalue of 0. (As defined in &qvalue;, a
    5735          qvalue of 0 means "not acceptable".)</t>
    5736 
    5737       <t>If multiple content-codings are acceptable, then the acceptable
    5738          content-coding with the highest non-zero qvalue is preferred.</t>
    5739   </list>
    5740 </t>
    5741 <t>
    5742    An Accept-Encoding header field with a combined field-value that is empty
    5743    implies that the user agent does not want any content-coding in response.
    5744    If an Accept-Encoding header field is present in a request and none of the
    5745    available representations for the response have a content-coding that
    5746    is listed as acceptable, the origin server &SHOULD; send a response
    5747    without any content-coding.
    5748 </t>
    5749 <t>
    5750    A request without an Accept-Encoding header field implies that the user
    5751    agent will accept any content-coding in response, but a representation
    5752    without content-coding is preferred for compatibility with the widest
    5753    variety of user agents.
    5754 </t>
    5755 <x:note>
    5756   <t>
    5757     <x:h>Note:</x:h> Most HTTP/1.0 applications do not recognize or obey qvalues
    5758     associated with content-codings. This means that qvalues will not
    5759     work and are not permitted with x-gzip or x-compress.
    5760   </t>
    5761 </x:note>
    5762 </section>
    5763 
    5764 <section title="Accept-Language" anchor="header.accept-language">
    5765   <iref primary="true" item="Accept-Language header field" x:for-anchor=""/>
    5766   <iref primary="true" item="Header Fields" subitem="Accept-Language" x:for-anchor=""/>
    5767   <x:anchor-alias value="Accept-Language"/>
    5768   <x:anchor-alias value="language-range"/>
    5769 <t>
    5770    The "Accept-Language" header field can be used by user agents to
    5771    indicate the set of natural languages that are preferred in the response.
    5772    Language tags are defined in <xref target="language.tags"/>.
    5773 </t>
    5774 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Accept-Language"/><iref primary="true" item="Grammar" subitem="language-range"/>
    5775   <x:ref>Accept-Language</x:ref> =
    5776                     1#( <x:ref>language-range</x:ref> [ <x:ref>OWS</x:ref> ";" <x:ref>OWS</x:ref> "q=" <x:ref>qvalue</x:ref> ] )
    5777   <x:ref>language-range</x:ref>  =
    5778             &lt;language-range, defined in <xref target="RFC4647" x:fmt="," x:sec="2.1"/>&gt;
    5779 </artwork></figure>
    5780 <t>
    5781    Each language-range can be given an associated quality value which
    5782    represents an estimate of the user's preference for the languages
    5783    specified by that range. The quality value defaults to "q=1". For
    5784    example,
    5785 </t>
    5786 <figure><artwork type="example">
    5787   Accept-Language: da, en-gb;q=0.8, en;q=0.7
    5788 </artwork></figure>
    5789 <t>
    5790    would mean: "I prefer Danish, but will accept British English and
    5791    other types of English".
    5792    (see also <xref target="RFC4647" x:sec="2.3" x:fmt="of"/>)
    5793 </t>
    5794 <t>
    5795    For matching, <xref target="RFC4647" x:sec="3" x:fmt="of"/> defines
    5796    several matching schemes. Implementations can offer the most appropriate
    5797    matching scheme for their requirements.
    5798 </t>
    5799 <x:note>
    5800   <t>
    5801     <x:h>Note:</x:h> The "Basic Filtering" scheme (<xref target="RFC4647"
    5802     x:fmt="," x:sec="3.3.1"/>) is identical to the matching scheme that was
    5803     previously defined in <xref target="RFC2616" x:fmt="of" x:sec="14.4"/>.
    5804   </t>
    5805 </x:note>
    5806 <t>
    5807    It might be contrary to the privacy expectations of the user to send
    5808    an Accept-Language header field with the complete linguistic preferences of
    5809    the user in every request. For a discussion of this issue, see
    5810    <xref target="privacy.issues.connected.to.accept.header.fields"/>.
    5811 </t>
    5812 <t>
    5813    As intelligibility is highly dependent on the individual user, it is
    5814    recommended that client applications make the choice of linguistic
    5815    preference available to the user. If the choice is not made
    5816    available, then the Accept-Language header field &MUST-NOT; be given in
    5817    the request.
    5818 </t>
    5819 <x:note>
    5820   <t>
    5821     <x:h>Note:</x:h> When making the choice of linguistic preference available to
    5822     the user, we remind implementors of  the fact that users are not
    5823     familiar with the details of language matching as described above,
    5824     and ought to be provided appropriate guidance. As an example, users
    5825     might assume that on selecting "en-gb", they will be served any
    5826     kind of English document if British English is not available. A
    5827     user agent might suggest in such a case to add "en" to get the
    5828     best matching behavior.
    5829   </t>
    5830 </x:note>
    5831 </section>
    5832 
    5833 <section title="Content-Encoding" anchor="header.content-encoding">
    5834   <iref primary="true" item="Content-Encoding header field" x:for-anchor=""/>
    5835   <iref primary="true" item="Header Fields" subitem="Content-Encoding" x:for-anchor=""/>
    5836   <x:anchor-alias value="Content-Encoding"/>
    5837 <t>
    5838    The "Content-Encoding" header field indicates what content-codings
    5839    have been applied to the representation beyond those inherent in the media
    5840    type, and thus what decoding mechanisms have to be applied in order to obtain
    5841    the media-type referenced by the Content-Type header field.
    5842    Content-Encoding is primarily used to allow a representation to be
    5843    compressed without losing the identity of its underlying media type.
    5844 </t>
    5845 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Encoding"/>
    5846   <x:ref>Content-Encoding</x:ref> = 1#<x:ref>content-coding</x:ref>
    5847 </artwork></figure>
    5848 <t>
    5849    Content codings are defined in <xref target="content.codings"/>. An example of its use is
    5850 </t>
    5851 <figure><artwork type="example">
    5852   Content-Encoding: gzip
    5853 </artwork></figure>
    5854 <t>
    5855    The content-coding is a characteristic of the representation.
    5856    Typically, the representation body is stored with this
    5857    encoding and is only decoded before rendering or analogous usage.
    5858    However, a transforming proxy &MAY; modify the content-coding if the
    5859    new coding is known to be acceptable to the recipient, unless the
    5860    "no-transform" cache-control directive is present in the message.
    5861 </t>
    5862 <t>
    5863    If the media type includes an inherent encoding, such as a data format
    5864    that is always compressed, then that encoding would not be restated as
    5865    a Content-Encoding even if it happens to be the same algorithm as one
    5866    of the content-codings.  Such a content-coding would only be listed if,
    5867    for some bizarre reason, it is applied a second time to form the
    5868    representation.  Likewise, an origin server might choose to publish the
    5869    same payload data as multiple representations that differ only in whether
    5870    the coding is defined as part of Content-Type or Content-Encoding, since
    5871    some user agents will behave differently in their handling of each
    5872    response (e.g., open a "Save as ..." dialog instead of automatic
    5873    decompression and rendering of content).
    5874 </t>
    5875 <t>
    5876    A representation that has a content-coding applied to it &MUST; include
    5877    a Content-Encoding header field (<xref target="header.content-encoding"/>)
    5878    that lists the content-coding(s) applied.
    5879 </t>
    5880 <t>
    5881    If multiple encodings have been applied to a representation, the content
    5882    codings &MUST; be listed in the order in which they were applied.
    5883    Additional information about the encoding parameters &MAY; be provided
    5884    by other header fields not defined by this specification.
    5885 </t>
    5886 <t>
    5887    If the content-coding of a representation in a request message is not
    5888    acceptable to the origin server, the server &SHOULD; respond with a
    5889    status code of 415 (Unsupported Media Type).
    5890 </t>
    5891 </section>
    5892 
    5893 <section title="Content-Language" anchor="header.content-language">
    5894   <iref primary="true" item="Content-Language header field" x:for-anchor=""/>
    5895   <iref primary="true" item="Header Fields" subitem="Content-Language" x:for-anchor=""/>
    5896   <x:anchor-alias value="Content-Language"/>
    5897 <t>
    5898    The "Content-Language" header field describes the natural
    5899    language(s) of the intended audience for the representation. Note that this might
    5900    not be equivalent to all the languages used within the representation.
    5901 </t>
    5902 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Language"/>
    5903   <x:ref>Content-Language</x:ref> = 1#<x:ref>language-tag</x:ref>
    5904 </artwork></figure>
    5905 <t>
    5906    Language tags are defined in <xref target="language.tags"/>. The primary purpose of
    5907    Content-Language is to allow a user to identify and differentiate
    5908    representations according to the user's own preferred language. Thus, if the
    5909    body content is intended only for a Danish-literate audience, the
    5910    appropriate field is
    5911 </t>
    5912 <figure><artwork type="example">
    5913   Content-Language: da
    5914 </artwork></figure>
    5915 <t>
    5916    If no Content-Language is specified, the default is that the content
    5917    is intended for all language audiences. This might mean that the
    5918    sender does not consider it to be specific to any natural language,
    5919    or that the sender does not know for which language it is intended.
    5920 </t>
    5921 <t>
    5922    Multiple languages &MAY; be listed for content that is intended for
    5923    multiple audiences. For example, a rendition of the "Treaty of
    5924    Waitangi", presented simultaneously in the original Maori and English
    5925    versions, would call for
    5926 </t>
    5927 <figure><artwork type="example">
    5928   Content-Language: mi, en
    5929 </artwork></figure>
    5930 <t>
    5931    However, just because multiple languages are present within a representation
    5932    does not mean that it is intended for multiple linguistic audiences.
    5933    An example would be a beginner's language primer, such as "A First
    5934    Lesson in Latin", which is clearly intended to be used by an
    5935    English-literate audience. In this case, the Content-Language would
    5936    properly only include "en".
    5937 </t>
    5938 <t>
    5939    Content-Language &MAY; be applied to any media type &mdash; it is not
    5940    limited to textual documents.
    5941 </t>
    5942 </section>
    5943 
    5944 <section title="Content-Location" anchor="header.content-location">
    5945   <iref primary="true" item="Content-Location header field" x:for-anchor=""/>
    5946   <iref primary="true" item="Header Fields" subitem="Content-Location" x:for-anchor=""/>
    5947   <x:anchor-alias value="Content-Location"/>
    5948 <t>
    5949    The "Content-Location" header field supplies a URI that can be used
    5950    as a specific identifier for the representation in this message.
    5951    In other words, if one were to perform a GET on this URI at the time
    5952    of this message's generation, then a 200 response would contain the
    5953    same representation that is enclosed as payload in this message.
    5954 </t>
    5955 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Location"/>
    5956   <x:ref>Content-Location</x:ref> = <x:ref>absolute-URI</x:ref> / <x:ref>partial-URI</x:ref>
    5957 </artwork></figure>
    5958 <t>
    5959    The Content-Location value is not a replacement for the effective
    5960    Request URI (&effective-request-uri;).  It is representation metadata.
    5961    It has the same syntax and semantics as the header field of the same name
    5962    defined for MIME body parts in <xref target="RFC2557" x:fmt="of" x:sec="4"/>.
    5963    However, its appearance in an HTTP message has some special implications
    5964    for HTTP recipients.
    5965 </t>
    5966 <t>
    5967    If Content-Location is included in a response message and its value
    5968    is the same as the effective request URI, then the response payload
    5969    &SHOULD; be considered a current representation of that resource.
    5970    For a GET or HEAD request, this is the same as the default semantics
    5971    when no Content-Location is provided by the server.  For a state-changing
    5972    request like PUT or POST, it implies that the server's response contains
    5973    the new representation of that resource, thereby distinguishing it from
    5974    representations that might only report about the action (e.g., "It worked!").
    5975    This allows authoring applications to update their local copies without
    5976    the need for a subsequent GET request.
    5977 </t>
    5978 <t>
    5979    If Content-Location is included in a response message and its value
    5980    differs from the effective request URI, then the origin server is
    5981    informing recipients that this representation has its own, presumably
    5982    more specific, identifier.  For a GET or HEAD request, this is an
    5983    indication that the effective request URI identifies a resource that
    5984    is subject to content negotiation and the selected representation for
    5985    this response can also be found at the identified URI.  For other
    5986    methods, such a Content-Location indicates that this representation
    5987    contains a report on the action's status and the same report is
    5988    available (for future access with GET) at the given URI.  For
    5989    example, a purchase transaction made via a POST request might
    5990    include a receipt document as the payload of the 200 response;
    5991    the Content-Location value provides an identifier for retrieving
    5992    a copy of that same receipt in the future.
    5993 </t>
    5994 <t>
    5995    If Content-Location is included in a request message, then it &MAY;
    5996    be interpreted by the origin server as an indication of where the
    5997    user agent originally obtained the content of the enclosed
    5998    representation (prior to any subsequent modification of the content
    5999    by that user agent).  In other words, the user agent is providing
    6000    the same representation metadata that it received with the original
    6001    representation.  However, such interpretation &MUST-NOT; be used to
    6002    alter the semantics of the method requested by the client.  For
    6003    example, if a client makes a PUT request on a negotiated resource
    6004    and the origin server accepts that PUT (without redirection), then the
    6005    new set of values for that resource is expected to be consistent with
    6006    the one representation supplied in that PUT; the Content-Location
    6007    cannot be used as a form of reverse content selection that
    6008    identifies only one of the negotiated representations to be updated.
    6009    If the user agent had wanted the latter semantics, it would have applied
    6010    the PUT directly to the Content-Location URI.
    6011 </t>
    6012 <t>
    6013    A Content-Location field received in a request message is transitory
    6014    information that &SHOULD-NOT; be saved with other representation
    6015    metadata for use in later responses.  The Content-Location's value
    6016    might be saved for use in other contexts, such as within source links
    6017    or other metadata.
    6018 </t>
    6019 <t>
    6020    A cache cannot assume that a representation with a Content-Location
    6021    different from the URI used to retrieve it can be used to respond to
    6022    later requests on that Content-Location URI.
    6023 </t>
    6024 <t>
    6025    If the Content-Location value is a partial URI, the partial URI is
    6026    interpreted relative to the effective request URI.
    6027 </t>
    6028 </section>
    6029 
    6030 <section title="Content-Type" anchor="header.content-type">
    6031   <iref primary="true" item="Content-Type header field" x:for-anchor=""/>
    6032   <iref primary="true" item="Header Fields" subitem="Content-Type" x:for-anchor=""/>
    6033   <x:anchor-alias value="Content-Type"/>
    6034 <t>
    6035    The "Content-Type" header field indicates the media type of the
    6036    representation. In the case of responses to the HEAD method, the media type is
    6037    that which would have been sent had the request been a GET.
    6038 </t>
    6039 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Content-Type"/>
    6040   <x:ref>Content-Type</x:ref> = <x:ref>media-type</x:ref>
    6041 </artwork></figure>
    6042 <t>
    6043    Media types are defined in <xref target="media.types"/>. An example of the field is
    6044 </t>
    6045 <figure><artwork type="example">
    6046   Content-Type: text/html; charset=ISO-8859-4
    6047 </artwork></figure>
    6048 <t>
    6049    Further discussion of Content-Type is provided in <xref target="representation.data"/>.
    6050 </t>
    6051 </section>
    6052 
    6053 </section>
    60546048
    60556049<section title="IANA Considerations" anchor="IANA.considerations3">

  • draft-ietf-httpbis/latest/p4-conditional.html

    r1643 r1645  
    896896      </div>
    897897      <h3 id="rfc.section.2.3.3"><a href="#rfc.section.2.3.3">2.3.3</a>&nbsp;<a id="example.entity.tag.vs.conneg" href="#example.entity.tag.vs.conneg">Example: Entity-tags varying on Content-Negotiated Resources</a></h3>
    898       <p id="rfc.section.2.3.3.p.1">Consider a resource that is subject to content negotiation (<a href="p2-semantics.html#content.negotiation" title="Content Negotiation">Appendix D.4</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), and where the representations returned upon a GET request vary based on the Accept-Encoding request header field (<a href="p2-semantics.html#header.accept-encoding" title="Accept-Encoding">Appendix D.5.3</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>):
     898      <p id="rfc.section.2.3.3.p.1">Consider a resource that is subject to content negotiation (<a href="p2-semantics.html#content.negotiation" title="Content Negotiation">Appendix D.3</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>), and where the representations returned upon a GET request vary based on the Accept-Encoding request header field (<a href="p2-semantics.html#header.accept-encoding" title="Accept-Encoding">Section 7.3</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>):
    899899      </p>
    900900      <div id="rfc.figure.u.6"></div>
    … …  
    11231123         as if it were the payload of a 200 response. The 304 response <em class="bcp14">MUST NOT</em> contain a message-body, and thus is always terminated by the first empty line after the header fields.
    11241124      </p>
    1125       <p id="rfc.section.4.1.p.2">A 304 response <em class="bcp14">MUST</em> include a Date header field (<a href="p2-semantics.html#header.date" title="Date">Section 7.2</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) unless the origin server does not have a clock that can provide a reasonable approximation of the current time. If a 200
     1125      <p id="rfc.section.4.1.p.2">A 304 response <em class="bcp14">MUST</em> include a Date header field (<a href="p2-semantics.html#header.date" title="Date">Section 7.10</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) unless the origin server does not have a clock that can provide a reasonable approximation of the current time. If a 200
    11261126         response to the same request would have included any of the header fields Cache-Control, Content-Location, ETag, Expires,
    11271127         or Vary, then those same header fields <em class="bcp14">MUST</em> be sent in a 304 response.
    … …  
    14251425                  <li><em>Part2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.1">1.2</a>, <a href="#rfc.xref.Part2.2">1.2</a>, <a href="#rfc.xref.Part2.3">2.3.3</a>, <a href="#rfc.xref.Part2.4">2.3.3</a>, <a href="#rfc.xref.Part2.5">4.1</a>, <a href="#Part2"><b>8.1</b></a><ul>
    14261426                        <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.2">1.2</a></li>
    1427                         <li><em>Section 7.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.5">4.1</a></li>
    1428                         <li><em>Appendix D.4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.3">2.3.3</a></li>
    1429                         <li><em>Appendix D.5.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.4">2.3.3</a></li>
     1427                        <li><em>Section 7.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.4">2.3.3</a></li>
     1428                        <li><em>Section 7.10</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.5">4.1</a></li>
     1429                        <li><em>Appendix D.3</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.3">2.3.3</a></li>
    14301430                     </ul>
    14311431                  </li>

  • draft-ietf-httpbis/latest/p6-cache.html

    r1643 r1645  
    987987         <li>HTTP/1.1 requires origin servers to send a Date header field, if possible, with every response, giving the time at which the
    988988            response was generated. The term "date_value" denotes the value of the Date header field, in a form appropriate for arithmetic
    989             operations. See <a href="p2-semantics.html#header.date" title="Date">Section 7.2</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for the definition of the Date header field, and for requirements regarding responses without it.
     989            operations. See <a href="p2-semantics.html#header.date" title="Date">Section 7.10</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for the definition of the Date header field, and for requirements regarding responses without it.
    990990         </li>
    991991      </ul>
    … …  
    21852185                        <li><em>Section 4</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.4">2.3.1.1</a></li>
    21862186                        <li><em>Section 6.1</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.1">1.4.2</a>, <a href="#rfc.xref.Part2.7">3.3</a></li>
    2187                         <li><em>Section 7.2</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.5">2.3.2</a></li>
     2187                        <li><em>Section 7.10</em>&nbsp;&nbsp;<a href="#rfc.xref.Part2.5">2.3.2</a></li>
    21882188                     </ul>
    21892189                  </li>
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