Changeset 344 for draft-ietf-httpbis


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11/11/08 02:47:01 (14 years ago)
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  • draft-ietf-httpbis/latest-roy/p1-messaging.html

    r342 r344  
    518518               <li class="tocline1">1.1&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
    519519               <li class="tocline1">1.2&nbsp;&nbsp;&nbsp;<a href="#notation">Syntax Notation</a><ul class="toc">
    520                      <li class="tocline1">1.2.1&nbsp;&nbsp;&nbsp;<a href="#notation.abnf">Augmented BNF</a><ul class="toc">
     520                     <li class="tocline1">1.2.1&nbsp;&nbsp;&nbsp;<a href="#notation.abnf">ABNF Extensions</a><ul class="toc">
    521521                           <li class="tocline1">1.2.1.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.1.2.1.1">#rule</a></li>
    522522                           <li class="tocline1">1.2.1.2&nbsp;&nbsp;&nbsp;<a href="#implied.LWS">implied *LWS</a></li>
    … …  
    683683      <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level requirements for the protocols it implements. An implementation that satisfies all the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level and all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "unconditionally compliant"; one that satisfies all the <em class="bcp14">MUST</em> level requirements but not all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "conditionally compliant."
    684684      </p>
     685      <div id="rfc.iref.g.1"></div>
     686      <div id="rfc.iref.g.2"></div>
     687      <div id="rfc.iref.g.3"></div>
     688      <div id="rfc.iref.g.4"></div>
     689      <div id="rfc.iref.g.5"></div>
     690      <div id="rfc.iref.g.6"></div>
     691      <div id="rfc.iref.g.7"></div>
     692      <div id="rfc.iref.g.8"></div>
     693      <div id="rfc.iref.g.9"></div>
     694      <div id="rfc.iref.g.10"></div>
     695      <div id="rfc.iref.g.11"></div>
     696      <div id="rfc.iref.g.12"></div>
    685697      <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a id="notation" href="#notation">Syntax Notation</a></h2>
    686       <p id="rfc.section.1.2.p.1">This specification uses the Augmented Backus-Naur Form (ABNF) notation of <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, including its core ABNF syntax rules: ALPHA (letters), CR (carriage return), DIGIT (decimal digits), DQUOTE (double quote),
    687          HEXDIG (hexadecimal digits), LF (line feed), and SP (space).
    688       </p>
    689698      <div id="core.rules">
    690          <p id="rfc.section.1.2.p.2">                    The following rules are used throughout this specification to describe basic parsing constructs. The US-ASCII coded character
    691             set is defined by ANSI X3.4-1986 <a href="#USASCII" id="rfc.xref.USASCII.1"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a>.
     699         <p id="rfc.section.1.2.p.1">                        This specification uses the Augmented Backus-Naur Form (ABNF) notation of <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="http://tools.ietf.org/html/rfc5234#section-B.1">Appendix B.1</a>: ALPHA (letters), CHAR (any <a href="#USASCII" id="rfc.xref.USASCII.1"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a> character, excluding NUL), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote),
     700            HEXDIG (hexadecimal 0-9/A-F/a-f), HTAB (horizontal tab), LF (line feed), OCTET (any 8-bit sequence of data), and SP (space).
    692701         </p>
    693702      </div>
    694       <div id="rfc.figure.u.1"></div><pre class="inline"><span id="rfc.iref.g.1"></span><span id="rfc.iref.g.2"></span><span id="rfc.iref.g.3"></span><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span>  <a href="#core.rules" class="smpl">OCTET</a>          = %x00-FF
    695                    ; any 8-bit sequence of data
    696   <a href="#core.rules" class="smpl">CHAR</a>           = %x01-7F
    697                    ; any US-ASCII character, excluding NUL
    698   <a href="#core.rules" class="smpl">ALPHA</a>          = %x41-5A / %x61-7A
    699                    ; A-Z / a-z
    700   <a href="#core.rules" class="smpl">DIGIT</a>          = %x30-39
    701                    ; any US-ASCII digit "0".."9"
    702   <a href="#core.rules" class="smpl">CTL</a>            = %x00-1F / %x7F
    703                    ; (octets 0 - 31) and DEL (127)
    704   <a href="#core.rules" class="smpl">CR</a>             = %x0D
    705                    ; US-ASCII CR, carriage return (13)
    706   <a href="#core.rules" class="smpl">LF</a>             = %x0A
    707                    ; US-ASCII LF, linefeed (10)
    708   <a href="#core.rules" class="smpl">SP</a>             = %x20
    709                    ; US-ASCII SP, space (32)
    710   <a href="#core.rules" class="smpl">HTAB</a>           = %x09
    711                    ; US-ASCII HT, horizontal-tab (9)
    712   <a href="#core.rules" class="smpl">DQUOTE</a>         = %x22
    713                    ; US-ASCII double-quote mark (34)
    714 </pre><h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a id="notation.abnf" href="#notation.abnf">Augmented BNF</a></h3>
    715       <p id="rfc.section.1.2.1.p.1">All of the mechanisms specified in this document are described in both prose and an augmented Backus-Naur Form (ABNF) based
    716          on that defined in <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Implementors will need to be familiar with the notation in order to understand this specification. The extensions to ABNF
    717          used in this specification are described below.
     703      <h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a id="notation.abnf" href="#notation.abnf">ABNF Extensions</a></h3>
     704      <p id="rfc.section.1.2.1.p.1">Two extensions to the ABNF rules of <a href="#RFC5234" id="rfc.xref.RFC5234.3"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> are used to improve readability. [The current plan is to remove these extensions prior to the last call draft.]
    718705      </p>
    719706      <h4 id="rfc.section.1.2.1.1"><a href="#rfc.section.1.2.1.1">1.2.1.1</a>&nbsp;#rule
    … …  
    722709         least &lt;n&gt; and at most &lt;m&gt; elements, each separated by one or more commas (",") and <em class="bcp14">OPTIONAL</em> linear white space (LWS). This makes the usual form of lists very easy; a rule such as
    723710      </p>
    724       <div id="rfc.figure.u.2"></div><pre class="text"> ( *<a href="#rule.LWS" class="smpl">LWS</a> element *( *<a href="#rule.LWS" class="smpl">LWS</a> "," *<a href="#rule.LWS" class="smpl">LWS</a> element ))</pre><p id="rfc.section.1.2.1.1.p.2">can be shown as </p>
    725       <div id="rfc.figure.u.3"></div><pre class="text"> 1#element</pre><p id="rfc.section.1.2.1.1.p.3">Wherever this construct is used, null elements are allowed, but do not contribute to the count of elements present. That is,
     711      <div id="rfc.figure.u.1"></div><pre class="text"> ( *<a href="#rule.LWS" class="smpl">LWS</a> element *( *<a href="#rule.LWS" class="smpl">LWS</a> "," *<a href="#rule.LWS" class="smpl">LWS</a> element ))</pre><p id="rfc.section.1.2.1.1.p.2">can be shown as </p>
     712      <div id="rfc.figure.u.2"></div><pre class="text"> 1#element</pre><p id="rfc.section.1.2.1.1.p.3">Wherever this construct is used, null elements are allowed, but do not contribute to the count of elements present. That is,
    726713         "(element), , (element) " is permitted, but counts as only two elements. Therefore, where at least one element is required,
    727714         at least one non-null element <em class="bcp14">MUST</em> be present. Default values are 0 and infinity so that "#element" allows any number, including zero; "1#element" requires at
    … …  
    737724      <h3 id="rfc.section.1.2.2"><a href="#rfc.section.1.2.2">1.2.2</a>&nbsp;<a id="basic.rules" href="#basic.rules">Basic Rules</a></h3>
    738725      <div id="rule.CRLF">
    739          <p id="rfc.section.1.2.2.p.1">  HTTP/1.1 defines the sequence CR LF as the end-of-line marker for all protocol elements except the entity-body (see <a href="#tolerant.applications" title="Tolerant Applications">Appendix&nbsp;A</a> for tolerant applications). The end-of-line marker within an entity-body is defined by its associated media type, as described
     726         <p id="rfc.section.1.2.2.p.1">HTTP/1.1 defines the sequence CRLF as the end-of-line marker for all protocol elements except the entity-body (see <a href="#tolerant.applications" title="Tolerant Applications">Appendix&nbsp;A</a> for tolerant applications). The end-of-line marker within an entity-body is defined by its associated media type, as described
    740727            in <a href="p3-payload.html#media.types" title="Media Types">Section 3.3</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
    741728         </p>
    742729      </div>
    743       <div id="rfc.figure.u.4"></div><pre class="inline"><span id="rfc.iref.g.11"></span>  <a href="#rule.CRLF" class="smpl">CRLF</a>           = <a href="#core.rules" class="smpl">CR</a> LF
    744 </pre><div id="rule.LWS">
    745          <p id="rfc.section.1.2.2.p.3">  HTTP/1.1 header field values can be folded onto multiple lines if the continuation line begins with a space or horizontal
     730      <div id="rule.LWS">
     731         <p id="rfc.section.1.2.2.p.2">  HTTP/1.1 header field values can be folded onto multiple lines if the continuation line begins with a space or horizontal
    746732            tab. All linear white space, including folding, has the same semantics as SP. A recipient <em class="bcp14">MAY</em> replace any linear white space with a single SP before interpreting the field value or forwarding the message downstream.
    747733         </p>
    748734      </div>
    749       <div id="rfc.figure.u.5"></div><pre class="inline"><span id="rfc.iref.g.12"></span>  <a href="#rule.LWS" class="smpl">LWS</a>            = [<a href="#rule.CRLF" class="smpl">CRLF</a>] 1*( <a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">HTAB</a> )
     735      <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.g.13"></span>  <a href="#rule.LWS" class="smpl">LWS</a>            = [<a href="#core.rules" class="smpl">CRLF</a>] 1*( <a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">HTAB</a> )
    750736</pre><div id="rule.TEXT">
    751          <p id="rfc.section.1.2.2.p.5">  The TEXT rule is only used for descriptive field contents and values that are not intended to be interpreted by the message
     737         <p id="rfc.section.1.2.2.p.4">  The TEXT rule is only used for descriptive field contents and values that are not intended to be interpreted by the message
    752738            parser. Words of *TEXT <em class="bcp14">MAY</em> contain characters from character sets other than ISO-8859-1 <a href="#ISO-8859-1" id="rfc.xref.ISO-8859-1.1"><cite title="Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1">[ISO-8859-1]</cite></a> only when encoded according to the rules of <a href="#RFC2047" id="rfc.xref.RFC2047.1"><cite title="MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text">[RFC2047]</cite></a>.
    753739         </p>
    754740      </div>
    755       <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.13"></span>  <a href="#rule.TEXT" class="smpl">TEXT</a>           = %x20-7E / %x80-FF / <a href="#rule.LWS" class="smpl">LWS</a>
     741      <div id="rfc.figure.u.4"></div><pre class="inline"><span id="rfc.iref.g.14"></span>  <a href="#rule.TEXT" class="smpl">TEXT</a>           = %x20-7E / %x80-FF / <a href="#rule.LWS" class="smpl">LWS</a>
    756742                 ; any <a href="#core.rules" class="smpl">OCTET</a> except <a href="#core.rules" class="smpl">CTL</a>s, but including <a href="#rule.LWS" class="smpl">LWS</a>
    757 </pre><p id="rfc.section.1.2.2.p.7">A CRLF is allowed in the definition of TEXT only as part of a header field continuation. It is expected that the folding LWS
     743</pre><p id="rfc.section.1.2.2.p.6">A CRLF is allowed in the definition of TEXT only as part of a header field continuation. It is expected that the folding LWS
    758744         will be replaced with a single SP before interpretation of the TEXT value.
    759745      </p>
    760       <div id="rule.HEXDIG">
    761          <p id="rfc.section.1.2.2.p.8">  Hexadecimal numeric characters are used in several protocol elements.</p>
    762       </div>
    763       <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.14"></span>  <a href="#rule.HEXDIG" class="smpl">HEXDIG</a>         = "A" / "B" / "C" / "D" / "E" / "F"
    764                  / "a" / "b" / "c" / "d" / "e" / "f" / <a href="#core.rules" class="smpl">DIGIT</a>
    765 </pre><div id="rule.token.separators">
    766          <p id="rfc.section.1.2.2.p.10">      Many HTTP/1.1 header field values consist of words separated by LWS or special characters. These special characters <em class="bcp14">MUST</em> be in a quoted string to be used within a parameter value (as defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.3</a>).
     746      <div id="rule.token.separators">
     747         <p id="rfc.section.1.2.2.p.7">      Many HTTP/1.1 header field values consist of words separated by LWS or special characters. These special characters <em class="bcp14">MUST</em> be in a quoted string to be used within a parameter value (as defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.3</a>).
    767748         </p>
    768749      </div>
    769       <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.15"></span><span id="rfc.iref.g.16"></span><span id="rfc.iref.g.17"></span>  <a href="#rule.token.separators" class="smpl">separators</a>     = "(" / ")" / "&lt;" / "&gt;" / "@"
     750      <div id="rfc.figure.u.5"></div><pre class="inline"><span id="rfc.iref.g.15"></span><span id="rfc.iref.g.16"></span><span id="rfc.iref.g.17"></span>  <a href="#rule.token.separators" class="smpl">separators</a>     = "(" / ")" / "&lt;" / "&gt;" / "@"
    770751                 / "," / ";" / ":" / "\" / <a href="#core.rules" class="smpl">DQUOTE</a>
    771752                 / "/" / "[" / "]" / "?" / "="
    … …  
    779760  <a href="#rule.token.separators" class="smpl">token</a>          = 1*<a href="#rule.token.separators" class="smpl">tchar</a>
    780761</pre><div id="rule.comment">
    781          <p id="rfc.section.1.2.2.p.12">    Comments can be included in some HTTP header fields by surrounding the comment text with parentheses. Comments are only allowed
     762         <p id="rfc.section.1.2.2.p.9">    Comments can be included in some HTTP header fields by surrounding the comment text with parentheses. Comments are only allowed
    782763            in fields containing "comment" as part of their field value definition. In all other fields, parentheses are considered part
    783764            of the field value.
    784765         </p>
    785766      </div>
    786       <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.18"></span><span id="rfc.iref.g.19"></span>  <a href="#rule.comment" class="smpl">comment</a>        = "(" *( <a href="#rule.comment" class="smpl">ctext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> / <a href="#rule.comment" class="smpl">comment</a> ) ")"
     767      <div id="rfc.figure.u.6"></div><pre class="inline"><span id="rfc.iref.g.18"></span><span id="rfc.iref.g.19"></span>  <a href="#rule.comment" class="smpl">comment</a>        = "(" *( <a href="#rule.comment" class="smpl">ctext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> / <a href="#rule.comment" class="smpl">comment</a> ) ")"
    787768  <a href="#rule.comment" class="smpl">ctext</a>          = &lt;any <a href="#rule.TEXT" class="smpl">TEXT</a> excluding "(" and ")"&gt;
    788769</pre><div id="rule.quoted-string">
    789          <p id="rfc.section.1.2.2.p.14">    A string of text is parsed as a single word if it is quoted using double-quote marks.</p>
     770         <p id="rfc.section.1.2.2.p.11">    A string of text is parsed as a single word if it is quoted using double-quote marks.</p>
    790771      </div>
    791       <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.20"></span><span id="rfc.iref.g.21"></span>  <a href="#rule.quoted-string" class="smpl">quoted-string</a>  = ( <a href="#core.rules" class="smpl">DQUOTE</a> *(<a href="#rule.quoted-string" class="smpl">qdtext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> ) <a href="#core.rules" class="smpl">DQUOTE</a> )
     772      <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.20"></span><span id="rfc.iref.g.21"></span>  <a href="#rule.quoted-string" class="smpl">quoted-string</a>  = ( <a href="#core.rules" class="smpl">DQUOTE</a> *(<a href="#rule.quoted-string" class="smpl">qdtext</a> / <a href="#rule.quoted-pair" class="smpl">quoted-pair</a> ) <a href="#core.rules" class="smpl">DQUOTE</a> )
    792773  <a href="#rule.quoted-string" class="smpl">qdtext</a>         = &lt;any <a href="#rule.TEXT" class="smpl">TEXT</a> excluding <a href="#core.rules" class="smpl">DQUOTE</a> and "\"&gt;
    793774</pre><div id="rule.quoted-pair">
    794          <p id="rfc.section.1.2.2.p.16">    The backslash character ("\") <em class="bcp14">MAY</em> be used as a single-character quoting mechanism only within quoted-string and comment constructs.
     775         <p id="rfc.section.1.2.2.p.13">    The backslash character ("\") <em class="bcp14">MAY</em> be used as a single-character quoting mechanism only within quoted-string and comment constructs.
    795776         </p>
    796777      </div>
    797       <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.22"></span><span id="rfc.iref.g.23"></span>  <a href="#rule.quoted-pair" class="smpl">quoted-text</a>    = %x01-09 /
     778      <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.22"></span><span id="rfc.iref.g.23"></span>  <a href="#rule.quoted-pair" class="smpl">quoted-text</a>    = %x01-09 /
    798779                   %x0B-0C /
    799780                   %x0E-FF ; Characters excluding NUL, <a href="#core.rules" class="smpl">CR</a> and <a href="#core.rules" class="smpl">LF</a>
    … …  
    801782</pre><h3 id="rfc.section.1.2.3"><a href="#rfc.section.1.2.3">1.2.3</a>&nbsp;<a id="abnf.dependencies" href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></h3>
    802783      <p id="rfc.section.1.2.3.p.1">The ABNF rules below are defined in other parts:</p>
    803       <div id="rfc.figure.u.12"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">request-header</a>  = &lt;request-header, defined in <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a>&gt;
     784      <div id="rfc.figure.u.9"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">request-header</a>  = &lt;request-header, defined in <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a>&gt;
    804785  <a href="#abnf.dependencies" class="smpl">response-header</a> = &lt;response-header, defined in <a href="#Part2" id="rfc.xref.Part2.2"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 6</a>&gt;
    805 </pre><div id="rfc.figure.u.13"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">accept-params</a>   = &lt;accept-params, defined in <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#header.accept" title="Accept">Section 6.1</a>&gt;
     786</pre><div id="rfc.figure.u.10"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">accept-params</a>   = &lt;accept-params, defined in <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#header.accept" title="Accept">Section 6.1</a>&gt;
    806787  <a href="#abnf.dependencies" class="smpl">entity-body</a>     = &lt;entity-body, defined in <a href="#Part3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.body" title="Entity Body">Section 4.2</a>&gt;
    807788  <a href="#abnf.dependencies" class="smpl">entity-header</a>   = &lt;entity-header, defined in <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>&gt;
    808 </pre><div id="rfc.figure.u.14"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">Cache-Control</a>   = &lt;Cache-Control, defined in <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
     789</pre><div id="rfc.figure.u.11"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">Cache-Control</a>   = &lt;Cache-Control, defined in <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
    809790  <a href="#abnf.dependencies" class="smpl">Pragma</a>          = &lt;Pragma, defined in <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 16.4</a>&gt;
    810791  <a href="#abnf.dependencies" class="smpl">Warning</a>         = &lt;Warning, defined in <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.warning" title="Warning">Section 16.6</a>&gt;
    … …  
    819800         "path-absolute", "query", and "authority" from <a href="#RFC3986" id="rfc.xref.RFC3986.3"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>:
    820801      </p>
    821       <div id="rfc.figure.u.15"></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><span id="rfc.iref.g.27"></span><span id="rfc.iref.g.28"></span><span id="rfc.iref.g.29"></span><span id="rfc.iref.g.30"></span>  <a href="#uri" class="smpl">absolute-URI</a>   = &lt;absolute-URI, defined in <a href="#RFC3986" id="rfc.xref.RFC3986.4"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.3">Section 4.3</a>&gt;
     802      <div id="rfc.figure.u.12"></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><span id="rfc.iref.g.27"></span><span id="rfc.iref.g.28"></span><span id="rfc.iref.g.29"></span><span id="rfc.iref.g.30"></span>  <a href="#uri" class="smpl">absolute-URI</a>   = &lt;absolute-URI, defined in <a href="#RFC3986" id="rfc.xref.RFC3986.4"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.3">Section 4.3</a>&gt;
    822803  <a href="#uri" class="smpl">authority</a>     = &lt;authority, defined in <a href="#RFC3986" id="rfc.xref.RFC3986.5"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-3.2">Section 3.2</a>&gt;
    823804  <a href="#uri" class="smpl">fragment</a>      = &lt;fragment, defined in <a href="#RFC3986" id="rfc.xref.RFC3986.6"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-3.5">Section 3.5</a>&gt;
    … …  
    841822         for identifiers using the http or https URI schemes.
    842823      </p>
    843       <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.31"></span>  <a href="#http.uri" class="smpl">http-URI</a> = "http:" "//" <a href="#uri" class="smpl">authority</a> <a href="#uri" class="smpl">path-abempty</a> [ "?" <a href="#uri" class="smpl">query</a> ]
     824      <div id="rfc.figure.u.13"></div><pre class="inline"><span id="rfc.iref.g.31"></span>  <a href="#http.uri" class="smpl">http-URI</a> = "http:" "//" <a href="#uri" class="smpl">authority</a> <a href="#uri" class="smpl">path-abempty</a> [ "?" <a href="#uri" class="smpl">query</a> ]
    844825</pre><p id="rfc.section.2.1.1.p.3">If the port is empty or not given, port 80 is assumed. The semantics are that the identified resource is located at the server
    845826         listening for TCP connections on that port of that host, and the Request-URI for the resource is path-absolute (<a href="#request-uri" title="Request-URI">Section&nbsp;5.1.2</a>). The use of IP addresses in URLs <em class="bcp14">SHOULD</em> be avoided whenever possible (see <a href="#RFC1900" id="rfc.xref.RFC1900.1"><cite title="Renumbering Needs Work">[RFC1900]</cite></a>). If the path-absolute is not present in the URL, it <em class="bcp14">MUST</em> be given as "/" when used as a Request-URI for a resource (<a href="#request-uri" title="Request-URI">Section&nbsp;5.1.2</a>). If a proxy receives a host name which is not a fully qualified domain name, it <em class="bcp14">MAY</em> add its domain to the host name it received. If a proxy receives a fully qualified domain name, the proxy <em class="bcp14">MUST NOT</em> change the host name.
    … …  
    860841         <li>An empty path-absolute is equivalent to an path-absolute of "/".</li>
    861842      </ul>
    862       <p id="rfc.section.2.1.2.p.2">Characters other than those in the "reserved" set (see <a href="#RFC3986" id="rfc.xref.RFC3986.12"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.2">Section 2.2</a>) are equivalent to their ""%" <a href="#rule.HEXDIG" class="smpl">HEXDIG</a>  <a href="#rule.HEXDIG" class="smpl">HEXDIG</a>" encoding.
     843      <p id="rfc.section.2.1.2.p.2">Characters other than those in the "reserved" set (see <a href="#RFC3986" id="rfc.xref.RFC3986.12"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.2">Section 2.2</a>) are equivalent to their ""%" <a href="#core.rules" class="smpl">HEXDIG</a>  <a href="#core.rules" class="smpl">HEXDIG</a>" encoding.
    863844      </p>
    864845      <p id="rfc.section.2.1.2.p.3">For example, the following three URIs are equivalent:</p>
    865       <div id="rfc.figure.u.17"></div><pre class="text">   http://example.com:80/~smith/home.html
     846      <div id="rfc.figure.u.14"></div><pre class="text">   http://example.com:80/~smith/home.html
    866847   http://EXAMPLE.com/%7Esmith/home.html
    867848   http://EXAMPLE.com:/%7esmith/home.html
    … …  
    877858         server (O).
    878859      </p>
    879       <div id="rfc.figure.u.18"></div><pre class="drawing">       request chain ------------------------&gt;
     860      <div id="rfc.figure.u.15"></div><pre class="drawing">       request chain ------------------------&gt;
    880861    UA -------------------v------------------- O
    881862       &lt;----------------------- response chain
    … …  
    888869         cannot understand the contents of the messages.
    889870      </p>
    890       <div id="rfc.figure.u.19"></div><pre class="drawing">       request chain --------------------------------------&gt;
     871      <div id="rfc.figure.u.16"></div><pre class="drawing">       request chain --------------------------------------&gt;
    891872    UA -----v----- A -----v----- B -----v----- C -----v----- O
    892873       &lt;------------------------------------- response chain
    … …  
    903884         O (via C) for a request which has not been cached by UA or A.
    904885      </p>
    905       <div id="rfc.figure.u.20"></div><pre class="drawing">          request chain ----------&gt;
     886      <div id="rfc.figure.u.17"></div><pre class="drawing">          request chain ----------&gt;
    906887       UA -----v----- A -----v----- B - - - - - - C - - - - - - O
    907888          &lt;--------- response chain
    … …  
    936917      </p>
    937918      <p id="rfc.section.3.1.p.2">The version of an HTTP message is indicated by an HTTP-Version field in the first line of the message. HTTP-Version is case-sensitive.</p>
    938       <div id="rfc.figure.u.21"></div><pre class="inline"><span id="rfc.iref.g.32"></span><span id="rfc.iref.g.33"></span>  <a href="#http.version" class="smpl">HTTP-Version</a>   = <a href="#http.version" class="smpl">HTTP-Prot-Name</a> "/" 1*<a href="#core.rules" class="smpl">DIGIT</a> "." 1*<a href="#core.rules" class="smpl">DIGIT</a>
     919      <div id="rfc.figure.u.18"></div><pre class="inline"><span id="rfc.iref.g.32"></span><span id="rfc.iref.g.33"></span>  <a href="#http.version" class="smpl">HTTP-Version</a>   = <a href="#http.version" class="smpl">HTTP-Prot-Name</a> "/" 1*<a href="#core.rules" class="smpl">DIGIT</a> "." 1*<a href="#core.rules" class="smpl">DIGIT</a>
    939920  <a href="#http.version" class="smpl">HTTP-Prot-Name</a> = %x48.54.54.50 ; "HTTP", case-sensitive
    940921</pre><p id="rfc.section.3.1.p.4">Note that the major and minor numbers <em class="bcp14">MUST</em> be treated as separate integers and that each <em class="bcp14">MAY</em> be incremented higher than a single digit. Thus, HTTP/2.4 is a lower version than HTTP/2.13, which in turn is lower than HTTP/12.3.
    … …  
    960941      <h3 id="rfc.section.3.2.1"><a href="#rfc.section.3.2.1">3.2.1</a>&nbsp;<a id="full.date" href="#full.date">Full Date</a></h3>
    961942      <p id="rfc.section.3.2.1.p.1">HTTP applications have historically allowed three different formats for the representation of date/time stamps:</p>
    962       <div id="rfc.figure.u.22"></div><pre class="text">   Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
     943      <div id="rfc.figure.u.19"></div><pre class="text">   Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123
    963944   Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
    964945   Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
    … …  
    975956         time zone, and <em class="bcp14">MUST</em> be assumed when reading the asctime format. HTTP-date is case sensitive and <em class="bcp14">MUST NOT</em> include additional LWS beyond that specifically included as SP in the grammar.
    976957      </p>
    977       <div id="rfc.figure.u.23"></div><pre class="inline"><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><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span><span id="rfc.iref.g.42"></span><span id="rfc.iref.g.43"></span><span id="rfc.iref.g.44"></span><span id="rfc.iref.g.45"></span>  <a href="#full.date" class="smpl">HTTP-date</a>    = <a href="#full.date" class="smpl">rfc1123-date</a> / <a href="#full.date" class="smpl">obsolete-date</a>
     958      <div id="rfc.figure.u.20"></div><pre class="inline"><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><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span><span id="rfc.iref.g.42"></span><span id="rfc.iref.g.43"></span><span id="rfc.iref.g.44"></span><span id="rfc.iref.g.45"></span>  <a href="#full.date" class="smpl">HTTP-date</a>    = <a href="#full.date" class="smpl">rfc1123-date</a> / <a href="#full.date" class="smpl">obsolete-date</a>
    978959  <a href="#full.date" class="smpl">obsolete-date</a> = <a href="#full.date" class="smpl">rfc850-date</a> / <a href="#full.date" class="smpl">asctime-date</a>
    979960  <a href="#full.date" class="smpl">rfc1123-date</a> = <a href="#full.date" class="smpl">wkday</a> "," <a href="#core.rules" class="smpl">SP</a> date1 <a href="#core.rules" class="smpl">SP</a> time <a href="#core.rules" class="smpl">SP</a> GMT
    … …  
    10341015         is a property of the message, not of the original entity.
    10351016      </p>
    1036       <div id="rfc.figure.u.24"></div><pre class="inline"><span id="rfc.iref.g.46"></span><span id="rfc.iref.g.47"></span>  <a href="#transfer.codings" class="smpl">transfer-coding</a>         = "chunked" / <a href="#transfer.codings" class="smpl">transfer-extension</a>
     1017      <div id="rfc.figure.u.21"></div><pre class="inline"><span id="rfc.iref.g.46"></span><span id="rfc.iref.g.47"></span>  <a href="#transfer.codings" class="smpl">transfer-coding</a>         = "chunked" / <a href="#transfer.codings" class="smpl">transfer-extension</a>
    10371018  <a href="#transfer.codings" class="smpl">transfer-extension</a>      = <a href="#rule.token.separators" class="smpl">token</a> *( ";" <a href="#transfer.codings" class="smpl">parameter</a> )
    10381019</pre><div id="rule.parameter">
    10391020         <p id="rfc.section.3.3.p.3">      Parameters are in the form of attribute/value pairs.</p>
    10401021      </div>
    1041       <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span><span id="rfc.iref.g.50"></span>  <a href="#transfer.codings" class="smpl">parameter</a>               = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a>
     1022      <div id="rfc.figure.u.22"></div><pre class="inline"><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span><span id="rfc.iref.g.50"></span>  <a href="#transfer.codings" class="smpl">parameter</a>               = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a>
    10421023  <a href="#rule.parameter" class="smpl">attribute</a>               = <a href="#rule.token.separators" class="smpl">token</a>
    10431024  <a href="#rule.parameter" class="smpl">value</a>                   = <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a>
    … …  
    10641045         necessary for the recipient to verify that it has received the full message.
    10651046      </p>
    1066       <div id="rfc.figure.u.26"></div><pre class="inline"><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span><span id="rfc.iref.g.53"></span><span id="rfc.iref.g.54"></span><span id="rfc.iref.g.55"></span><span id="rfc.iref.g.56"></span><span id="rfc.iref.g.57"></span><span id="rfc.iref.g.58"></span><span id="rfc.iref.g.59"></span>  <a href="#chunked.transfer.encoding" class="smpl">Chunked-Body</a>   = *<a href="#chunked.transfer.encoding" class="smpl">chunk</a>
     1047      <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span><span id="rfc.iref.g.53"></span><span id="rfc.iref.g.54"></span><span id="rfc.iref.g.55"></span><span id="rfc.iref.g.56"></span><span id="rfc.iref.g.57"></span><span id="rfc.iref.g.58"></span><span id="rfc.iref.g.59"></span>  <a href="#chunked.transfer.encoding" class="smpl">Chunked-Body</a>   = *<a href="#chunked.transfer.encoding" class="smpl">chunk</a>
    10671048                   <a href="#chunked.transfer.encoding" class="smpl">last-chunk</a>
    10681049                   <a href="#chunked.transfer.encoding" class="smpl">trailer-part</a>
    1069                    <a href="#rule.CRLF" class="smpl">CRLF</a>
     1050                   <a href="#core.rules" class="smpl">CRLF</a>
    10701051 
    1071   <a href="#chunked.transfer.encoding" class="smpl">chunk</a>          = <a href="#chunked.transfer.encoding" class="smpl">chunk-size</a> [ <a href="#chunked.transfer.encoding" class="smpl">chunk-extension</a> ] <a href="#rule.CRLF" class="smpl">CRLF</a>
    1072                    <a href="#chunked.transfer.encoding" class="smpl">chunk-data</a> <a href="#rule.CRLF" class="smpl">CRLF</a>
    1073   <a href="#chunked.transfer.encoding" class="smpl">chunk-size</a>     = 1*<a href="#rule.HEXDIG" class="smpl">HEXDIG</a>
    1074   <a href="#chunked.transfer.encoding" class="smpl">last-chunk</a>     = 1*("0") [ <a href="#chunked.transfer.encoding" class="smpl">chunk-extension</a> ] <a href="#rule.CRLF" class="smpl">CRLF</a>
     1052  <a href="#chunked.transfer.encoding" class="smpl">chunk</a>          = <a href="#chunked.transfer.encoding" class="smpl">chunk-size</a> [ <a href="#chunked.transfer.encoding" class="smpl">chunk-extension</a> ] <a href="#core.rules" class="smpl">CRLF</a>
     1053                   <a href="#chunked.transfer.encoding" class="smpl">chunk-data</a> <a href="#core.rules" class="smpl">CRLF</a>
     1054  <a href="#chunked.transfer.encoding" class="smpl">chunk-size</a>     = 1*<a href="#core.rules" class="smpl">HEXDIG</a>
     1055  <a href="#chunked.transfer.encoding" class="smpl">last-chunk</a>     = 1*("0") [ <a href="#chunked.transfer.encoding" class="smpl">chunk-extension</a> ] <a href="#core.rules" class="smpl">CRLF</a>
    10751056 
    10761057  <a href="#chunked.transfer.encoding" class="smpl">chunk-extension</a>= *( ";" <a href="#chunked.transfer.encoding" class="smpl">chunk-ext-name</a> [ "=" <a href="#chunked.transfer.encoding" class="smpl">chunk-ext-val</a> ] )
    … …  
    10781059  <a href="#chunked.transfer.encoding" class="smpl">chunk-ext-val</a>  = <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a>
    10791060  <a href="#chunked.transfer.encoding" class="smpl">chunk-data</a>     = 1*<a href="#core.rules" class="smpl">OCTET</a> ; a sequence of chunk-size octets
    1080   <a href="#chunked.transfer.encoding" class="smpl">trailer-part</a>   = *(<a href="#abnf.dependencies" class="smpl">entity-header</a> <a href="#rule.CRLF" class="smpl">CRLF</a>)
     1061  <a href="#chunked.transfer.encoding" class="smpl">trailer-part</a>   = *(<a href="#abnf.dependencies" class="smpl">entity-header</a> <a href="#core.rules" class="smpl">CRLF</a>)
    10811062</pre><p id="rfc.section.3.3.1.p.3">The chunk-size field is a string of hex digits indicating the size of the chunk-data in octets. The chunked encoding is ended
    10821063         by any chunk whose size is zero, followed by the trailer, which is terminated by an empty line.
    … …  
    11011082      </p>
    11021083      <p id="rfc.section.3.3.1.p.7">A process for decoding the "chunked" transfer-coding can be represented in pseudo-code as:</p>
    1103       <div id="rfc.figure.u.27"></div><pre class="text">    length := 0
     1084      <div id="rfc.figure.u.24"></div><pre class="text">    length := 0
    11041085    read chunk-size, chunk-extension (if any) and CRLF
    11051086    while (chunk-size &gt; 0) {
    … …  
    11231104         space. By convention, the products are listed in order of their significance for identifying the application.
    11241105      </p>
    1125       <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.60"></span><span id="rfc.iref.g.61"></span>  <a href="#product.tokens" class="smpl">product</a>         = <a href="#rule.token.separators" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>]
     1106      <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.60"></span><span id="rfc.iref.g.61"></span>  <a href="#product.tokens" class="smpl">product</a>         = <a href="#rule.token.separators" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>]
    11261107  <a href="#product.tokens" class="smpl">product-version</a> = <a href="#rule.token.separators" class="smpl">token</a>
    11271108</pre><p id="rfc.section.3.4.p.3">Examples:</p>
    1128       <div id="rfc.figure.u.29"></div><pre class="text">    User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     1109      <div id="rfc.figure.u.26"></div><pre class="text">    User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    11291110    Server: Apache/0.8.4
    11301111</pre><p id="rfc.section.3.4.p.5">Product tokens <em class="bcp14">SHOULD</em> be short and to the point. They <em class="bcp14">MUST NOT</em> be used for advertising or other non-essential information. Although any token character <em class="bcp14">MAY</em> appear in a product-version, this token <em class="bcp14">SHOULD</em> only be used for a version identifier (i.e., successive versions of the same product <em class="bcp14">SHOULD</em> only differ in the product-version portion of the product value).
    … …  
    11331114      <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="message.types" href="#message.types">Message Types</a></h2>
    11341115      <p id="rfc.section.4.1.p.1">HTTP messages consist of requests from client to server and responses from server to client.</p>
    1135       <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.62"></span>  <a href="#message.types" class="smpl">HTTP-message</a>   = <a href="#request" class="smpl">Request</a> / <a href="#response" class="smpl">Response</a>     ; HTTP/1.1 messages
     1116      <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.62"></span>  <a href="#message.types" class="smpl">HTTP-message</a>   = <a href="#request" class="smpl">Request</a> / <a href="#response" class="smpl">Response</a>     ; HTTP/1.1 messages
    11361117</pre><p id="rfc.section.4.1.p.3">Request (<a href="#request" title="Request">Section&nbsp;5</a>) and Response (<a href="#response" title="Response">Section&nbsp;6</a>) messages use the generic message format of <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a> for transferring entities (the payload of the message). Both types of message consist of a start-line, zero or more header
    11371118         fields (also known as "headers"), an empty line (i.e., a line with nothing preceding the CRLF) indicating the end of the header
    11381119         fields, and possibly a message-body.
    11391120      </p>
    1140       <div id="rfc.figure.u.31"></div><pre class="inline"><span id="rfc.iref.g.63"></span><span id="rfc.iref.g.64"></span>  <a href="#message.types" class="smpl">generic-message</a> = <a href="#message.types" class="smpl">start-line</a>
    1141                     *(<a href="#message.headers" class="smpl">message-header</a> <a href="#rule.CRLF" class="smpl">CRLF</a>)
    1142                     <a href="#rule.CRLF" class="smpl">CRLF</a>
     1121      <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.63"></span><span id="rfc.iref.g.64"></span>  <a href="#message.types" class="smpl">generic-message</a> = <a href="#message.types" class="smpl">start-line</a>
     1122                    *(<a href="#message.headers" class="smpl">message-header</a> <a href="#core.rules" class="smpl">CRLF</a>)
     1123                    <a href="#core.rules" class="smpl">CRLF</a>
    11431124                    [ <a href="#message.body" class="smpl">message-body</a> ]
    11441125  <a href="#message.types" class="smpl">start-line</a>      = <a href="#request-line" class="smpl">Request-Line</a> / <a href="#status-line" class="smpl">Status-Line</a>
    … …  
    11561137         forms.
    11571138      </p>
    1158       <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.65"></span><span id="rfc.iref.g.66"></span><span id="rfc.iref.g.67"></span><span id="rfc.iref.g.68"></span>  <a href="#message.headers" class="smpl">message-header</a> = <a href="#message.headers" class="smpl">field-name</a> ":" [ <a href="#message.headers" class="smpl">field-value</a> ]
     1139      <div id="rfc.figure.u.29"></div><pre class="inline"><span id="rfc.iref.g.65"></span><span id="rfc.iref.g.66"></span><span id="rfc.iref.g.67"></span><span id="rfc.iref.g.68"></span>  <a href="#message.headers" class="smpl">message-header</a> = <a href="#message.headers" class="smpl">field-name</a> ":" [ <a href="#message.headers" class="smpl">field-value</a> ]
    11591140  <a href="#message.headers" class="smpl">field-name</a>     = <a href="#rule.token.separators" class="smpl">token</a>
    11601141  <a href="#message.headers" class="smpl">field-value</a>    = *( <a href="#message.headers" class="smpl">field-content</a> / <a href="#rule.LWS" class="smpl">LWS</a> )
    … …  
    11871168         header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section&nbsp;8.7</a>).
    11881169      </p>
    1189       <div id="rfc.figure.u.33"></div><pre class="inline"><span id="rfc.iref.g.69"></span>  <a href="#message.body" class="smpl">message-body</a> = <a href="#abnf.dependencies" class="smpl">entity-body</a>
     1170      <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.69"></span>  <a href="#message.body" class="smpl">message-body</a> = <a href="#abnf.dependencies" class="smpl">entity-body</a>
    11901171               / &lt;entity-body encoded as per <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>&gt;
    11911172</pre><p id="rfc.section.4.3.p.3">Transfer-Encoding <em class="bcp14">MUST</em> be used to indicate any transfer-codings applied by an application to ensure safe and proper transfer of the message. Transfer-Encoding
    … …  
    12551236         to the entity being transferred. These header fields apply only to the message being transmitted.
    12561237      </p>
    1257       <div id="rfc.figure.u.34"></div><pre class="inline"><span id="rfc.iref.g.70"></span>  <a href="#general.header.fields" class="smpl">general-header</a> = <a href="#abnf.dependencies" class="smpl">Cache-Control</a>            ; <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 16.2</a>
     1238      <div id="rfc.figure.u.31"></div><pre class="inline"><span id="rfc.iref.g.70"></span>  <a href="#general.header.fields" class="smpl">general-header</a> = <a href="#abnf.dependencies" class="smpl">Cache-Control</a>            ; <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 16.2</a>
    12581239                 / <a href="#header.connection" class="smpl">Connection</a>               ; <a href="#header.connection" id="rfc.xref.header.connection.1" title="Connection">Section&nbsp;8.1</a>
    12591240                 / <a href="#header.date" class="smpl">Date</a>                     ; <a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section&nbsp;8.3</a>
    … …  
    12721253         resource, the identifier of the resource, and the protocol version in use.
    12731254      </p>
    1274       <div id="rfc.figure.u.35"></div><pre class="inline"><span id="rfc.iref.g.71"></span>  <a href="#request" class="smpl">Request</a>       = <a href="#request-line" class="smpl">Request-Line</a>              ; <a href="#request-line" title="Request-Line">Section&nbsp;5.1</a>
     1255      <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.71"></span>  <a href="#request" class="smpl">Request</a>       = <a href="#request-line" class="smpl">Request-Line</a>              ; <a href="#request-line" title="Request-Line">Section&nbsp;5.1</a>
    12751256                  *(( <a href="#general.header.fields" class="smpl">general-header</a>        ; <a href="#general.header.fields" title="General Header Fields">Section&nbsp;4.5</a>
    12761257                   / <a href="#abnf.dependencies" class="smpl">request-header</a>         ; <a href="#Part2" id="rfc.xref.Part2.7"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 4</a>
    1277                    / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#rule.CRLF" class="smpl">CRLF</a>)  ; <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>
    1278                   <a href="#rule.CRLF" class="smpl">CRLF</a>
     1258                   / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#core.rules" class="smpl">CRLF</a>)  ; <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>
     1259                  <a href="#core.rules" class="smpl">CRLF</a>
    12791260                  [ <a href="#message.body" class="smpl">message-body</a> ]          ; <a href="#message.body" title="Message Body">Section&nbsp;4.3</a>
    12801261</pre><h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a>&nbsp;<a id="request-line" href="#request-line">Request-Line</a></h2>
    … …  
    12821263         elements are separated by SP characters. No CR or LF is allowed except in the final CRLF sequence.
    12831264      </p>
    1284       <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.72"></span>  <a href="#request-line" class="smpl">Request-Line</a>   = <a href="#method" class="smpl">Method</a> <a href="#core.rules" class="smpl">SP</a> <a href="#request-uri" class="smpl">Request-URI</a> <a href="#core.rules" class="smpl">SP</a> <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#rule.CRLF" class="smpl">CRLF</a>
     1265      <div id="rfc.figure.u.33"></div><pre class="inline"><span id="rfc.iref.g.72"></span>  <a href="#request-line" class="smpl">Request-Line</a>   = <a href="#method" class="smpl">Method</a> <a href="#core.rules" class="smpl">SP</a> <a href="#request-uri" class="smpl">Request-URI</a> <a href="#core.rules" class="smpl">SP</a> <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">CRLF</a>
    12851266</pre><h3 id="rfc.section.5.1.1"><a href="#rfc.section.5.1.1">5.1.1</a>&nbsp;<a id="method" href="#method">Method</a></h3>
    12861267      <p id="rfc.section.5.1.1.p.1">The Method token indicates the method to be performed on the resource identified by the Request-URI. The method is case-sensitive.</p>
    1287       <div id="rfc.figure.u.37"></div><pre class="inline"><span id="rfc.iref.g.73"></span><span id="rfc.iref.g.74"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#rule.token.separators" class="smpl">token</a>
     1268      <div id="rfc.figure.u.34"></div><pre class="inline"><span id="rfc.iref.g.73"></span><span id="rfc.iref.g.74"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#rule.token.separators" class="smpl">token</a>
    12881269</pre><h3 id="rfc.section.5.1.2"><a href="#rfc.section.5.1.2">5.1.2</a>&nbsp;<a id="request-uri" href="#request-uri">Request-URI</a></h3>
    12891270      <p id="rfc.section.5.1.2.p.1">The Request-URI is a Uniform Resource Identifier (<a href="#uri" title="Uniform Resource Identifiers">Section&nbsp;2.1</a>) and identifies the resource upon which to apply the request.
    12901271      </p>
    1291       <div id="rfc.figure.u.38"></div><pre class="inline"><span id="rfc.iref.g.75"></span>  <a href="#request-uri" class="smpl">Request-URI</a>    = "*"
     1272      <div id="rfc.figure.u.35"></div><pre class="inline"><span id="rfc.iref.g.75"></span>  <a href="#request-uri" class="smpl">Request-URI</a>    = "*"
    12921273                 / <a href="#uri" class="smpl">absolute-URI</a>
    12931274                 / ( <a href="#uri" class="smpl">path-absolute</a> [ "?" <a href="#uri" class="smpl">query</a> ] )
    … …  
    12971278         apply to a resource. One example would be
    12981279      </p>
    1299       <div id="rfc.figure.u.39"></div><pre class="text">    OPTIONS * HTTP/1.1
     1280      <div id="rfc.figure.u.36"></div><pre class="text">    OPTIONS * HTTP/1.1
    13001281</pre><p id="rfc.section.5.1.2.p.5">The absolute-URI form is <em class="bcp14">REQUIRED</em> when the request is being made to a proxy. The proxy is requested to forward the request or service it from a valid cache,
    13011282         and return the response. Note that the proxy <em class="bcp14">MAY</em> forward the request on to another proxy or directly to the server specified by the absolute-URI. In order to avoid request
    … …  
    13031284         Request-Line would be:
    13041285      </p>
    1305       <div id="rfc.figure.u.40"></div><pre class="text">    GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
     1286      <div id="rfc.figure.u.37"></div><pre class="text">    GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
    13061287</pre><p id="rfc.section.5.1.2.p.7">To allow for transition to absolute-URIs in all requests in future versions of HTTP, all HTTP/1.1 servers <em class="bcp14">MUST</em> accept the absolute-URI form in requests, even though HTTP/1.1 clients will only generate them in requests to proxies.
    13071288      </p>
    … …  
    13121293         server would create a TCP connection to port 80 of the host "www.example.org" and send the lines:
    13131294      </p>
    1314       <div id="rfc.figure.u.41"></div><pre class="text">    GET /pub/WWW/TheProject.html HTTP/1.1
     1295      <div id="rfc.figure.u.38"></div><pre class="text">    GET /pub/WWW/TheProject.html HTTP/1.1
    13151296    Host: www.example.org
    13161297</pre><p id="rfc.section.5.1.2.p.11">followed by the remainder of the Request. Note that the absolute path cannot be empty; if none is present in the original
    13171298         URI, it <em class="bcp14">MUST</em> be given as "/" (the server root).
    13181299      </p>
    1319       <p id="rfc.section.5.1.2.p.12">The Request-URI is transmitted in the format specified in <a href="#http.uri" title="http URI scheme">Section&nbsp;2.1.1</a>. If the Request-URI is encoded using the "% <a href="#rule.HEXDIG" class="smpl">HEXDIG</a>  <a href="#rule.HEXDIG" class="smpl">HEXDIG</a>" encoding (<a href="#RFC3986" id="rfc.xref.RFC3986.13"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.4">Section 2.4</a>), the origin server <em class="bcp14">MUST</em> decode the Request-URI in order to properly interpret the request. Servers <em class="bcp14">SHOULD</em> respond to invalid Request-URIs with an appropriate status code.
     1300      <p id="rfc.section.5.1.2.p.12">The Request-URI is transmitted in the format specified in <a href="#http.uri" title="http URI scheme">Section&nbsp;2.1.1</a>. If the Request-URI is encoded using the "% <a href="#core.rules" class="smpl">HEXDIG</a>  <a href="#core.rules" class="smpl">HEXDIG</a>" encoding (<a href="#RFC3986" id="rfc.xref.RFC3986.13"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.4">Section 2.4</a>), the origin server <em class="bcp14">MUST</em> decode the Request-URI in order to properly interpret the request. Servers <em class="bcp14">SHOULD</em> respond to invalid Request-URIs with an appropriate status code.
    13201301      </p>
    13211302      <p id="rfc.section.5.1.2.p.13">A transparent proxy <em class="bcp14">MUST NOT</em> rewrite the "path-absolute" part of the received Request-URI when forwarding it to the next inbound server, except as noted
    … …  
    13501331      <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="response" href="#response">Response</a></h1>
    13511332      <p id="rfc.section.6.p.1">After receiving and interpreting a request message, a server responds with an HTTP response message.</p>
    1352       <div id="rfc.figure.u.42"></div><pre class="inline"><span id="rfc.iref.g.76"></span>  <a href="#response" class="smpl">Response</a>      = <a href="#status-line" class="smpl">Status-Line</a>               ; <a href="#status-line" title="Status-Line">Section&nbsp;6.1</a>
     1333      <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.76"></span>  <a href="#response" class="smpl">Response</a>      = <a href="#status-line" class="smpl">Status-Line</a>               ; <a href="#status-line" title="Status-Line">Section&nbsp;6.1</a>
    13531334                  *(( <a href="#general.header.fields" class="smpl">general-header</a>        ; <a href="#general.header.fields" title="General Header Fields">Section&nbsp;4.5</a>
    13541335                   / <a href="#abnf.dependencies" class="smpl">response-header</a>        ; <a href="#Part2" id="rfc.xref.Part2.9"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 6</a>
    1355                    / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#rule.CRLF" class="smpl">CRLF</a>)  ; <a href="#Part3" id="rfc.xref.Part3.10"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>
    1356                   <a href="#rule.CRLF" class="smpl">CRLF</a>
     1336                   / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#core.rules" class="smpl">CRLF</a>)  ; <a href="#Part3" id="rfc.xref.Part3.10"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 4.1</a>
     1337                  <a href="#core.rules" class="smpl">CRLF</a>
    13571338                  [ <a href="#message.body" class="smpl">message-body</a> ]          ; <a href="#message.body" title="Message Body">Section&nbsp;4.3</a>
    13581339</pre><h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="status-line" href="#status-line">Status-Line</a></h2>
    … …  
    13611342         CRLF sequence.
    13621343      </p>
    1363       <div id="rfc.figure.u.43"></div><pre class="inline"><span id="rfc.iref.g.77"></span>  <a href="#status-line" class="smpl">Status-Line</a> = <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a> <a href="#rule.CRLF" class="smpl">CRLF</a>
     1344      <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.77"></span>  <a href="#status-line" class="smpl">Status-Line</a> = <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a> <a href="#core.rules" class="smpl">CRLF</a>
    13641345</pre><h3 id="rfc.section.6.1.1"><a href="#rfc.section.6.1.1">6.1.1</a>&nbsp;<a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h3>
    13651346      <p id="rfc.section.6.1.1.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request. These codes
    … …  
    13781359         <li>5xx: Server Error - The server failed to fulfill an apparently valid request</li>
    13791360      </ul>
    1380       <div id="rfc.figure.u.44"></div><pre class="inline"><span id="rfc.iref.g.78"></span><span id="rfc.iref.g.79"></span><span id="rfc.iref.g.80"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#core.rules" class="smpl">DIGIT</a>
     1361      <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.78"></span><span id="rfc.iref.g.79"></span><span id="rfc.iref.g.80"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#core.rules" class="smpl">DIGIT</a>
    13811362  <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a>  = *&lt;<a href="#rule.TEXT" class="smpl">TEXT</a>, excluding <a href="#core.rules" class="smpl">CR</a>, <a href="#core.rules" class="smpl">LF</a>&gt;
    13821363</pre><h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="connections" href="#connections">Connections</a></h1>
    … …  
    15691550      </p>
    15701551      <p id="rfc.section.8.1.p.2">The Connection header has the following grammar:</p>
    1571       <div id="rfc.figure.u.45"></div><pre class="inline"><span id="rfc.iref.g.81"></span><span id="rfc.iref.g.82"></span>  <a href="#header.connection" class="smpl">Connection</a> = "Connection" ":" 1#(<a href="#header.connection" class="smpl">connection-token</a>)
     1552      <div id="rfc.figure.u.42"></div><pre class="inline"><span id="rfc.iref.g.81"></span><span id="rfc.iref.g.82"></span>  <a href="#header.connection" class="smpl">Connection</a> = "Connection" ":" 1#(<a href="#header.connection" class="smpl">connection-token</a>)
    15721553  <a href="#header.connection" class="smpl">connection-token</a>  = <a href="#rule.token.separators" class="smpl">token</a>
    15731554</pre><p id="rfc.section.8.1.p.4">HTTP/1.1 proxies <em class="bcp14">MUST</em> parse the Connection header field before a message is forwarded and, for each connection-token in this field, remove any header
    … …  
    15811562         of the response. For example,
    15821563      </p>
    1583       <div id="rfc.figure.u.46"></div><pre class="text">    Connection: close
     1564      <div id="rfc.figure.u.43"></div><pre class="text">    Connection: close
    15841565</pre><p id="rfc.section.8.1.p.8">in either the request or the response header fields indicates that the connection <em class="bcp14">SHOULD NOT</em> be considered `persistent' (<a href="#persistent.connections" title="Persistent Connections">Section&nbsp;7.1</a>) after the current request/response is complete.
    15851566      </p>
    … …  
    15971578         or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET.
    15981579      </p>
    1599       <div id="rfc.figure.u.47"></div><pre class="inline"><span id="rfc.iref.g.83"></span>  <a href="#header.content-length" class="smpl">Content-Length</a>    = "Content-Length" ":" 1*<a href="#core.rules" class="smpl">DIGIT</a>
     1580      <div id="rfc.figure.u.44"></div><pre class="inline"><span id="rfc.iref.g.83"></span>  <a href="#header.content-length" class="smpl">Content-Length</a>    = "Content-Length" ":" 1*<a href="#core.rules" class="smpl">DIGIT</a>
    16001581</pre><p id="rfc.section.8.2.p.3">An example is</p>
    1601       <div id="rfc.figure.u.48"></div><pre class="text">    Content-Length: 3495
     1582      <div id="rfc.figure.u.45"></div><pre class="text">    Content-Length: 3495
    16021583</pre><p id="rfc.section.8.2.p.5">Applications <em class="bcp14">SHOULD</em> use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in <a href="#message.length" title="Message Length">Section&nbsp;4.4</a>.
    16031584      </p>
    … …  
    16141595         as orig-date 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.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as described in <a href="#full.date" title="Full Date">Section&nbsp;3.2.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
    16151596      </p>
    1616       <div id="rfc.figure.u.49"></div><pre class="inline"><span id="rfc.iref.g.84"></span>  <a href="#header.date" class="smpl">Date</a>  = "Date" ":" <a href="#full.date" class="smpl">HTTP-date</a>
     1597      <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.84"></span>  <a href="#header.date" class="smpl">Date</a>  = "Date" ":" <a href="#full.date" class="smpl">HTTP-date</a>
    16171598</pre><p id="rfc.section.8.3.p.3">An example is</p>
    1618       <div id="rfc.figure.u.50"></div><pre class="text">    Date: Tue, 15 Nov 1994 08:12:31 GMT
     1599      <div id="rfc.figure.u.47"></div><pre class="text">    Date: Tue, 15 Nov 1994 08:12:31 GMT
    16191600</pre><p id="rfc.section.8.3.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
    16201601      </p>
    … …  
    16521633         a single IP address.
    16531634      </p>
    1654       <div id="rfc.figure.u.51"></div><pre class="inline"><span id="rfc.iref.g.85"></span>  <a href="#header.host" class="smpl">Host</a> = "Host" ":" <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ; <a href="#http.uri" title="http URI scheme">Section&nbsp;2.1.1</a>
     1635      <div id="rfc.figure.u.48"></div><pre class="inline"><span id="rfc.iref.g.85"></span>  <a href="#header.host" class="smpl">Host</a> = "Host" ":" <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ; <a href="#http.uri" title="http URI scheme">Section&nbsp;2.1.1</a>
    16551636</pre><p id="rfc.section.8.4.p.3">A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP
    16561637         URL). For example, a request on the origin server for &lt;http://www.example.org/pub/WWW/&gt; would properly include:
    16571638      </p>
    1658       <div id="rfc.figure.u.52"></div><pre class="text">    GET /pub/WWW/ HTTP/1.1
     1639      <div id="rfc.figure.u.49"></div><pre class="text">    GET /pub/WWW/ HTTP/1.1
    16591640    Host: www.example.org
    16601641</pre><p id="rfc.section.8.4.p.5">A client <em class="bcp14">MUST</em> include a Host header field in all HTTP/1.1 request messages. If the requested URI does not include an Internet host name
    … …  
    16711652         and/or a comma-separated list of extension transfer-coding names with optional accept parameters (as described in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.3</a>).
    16721653      </p>
    1673       <div id="rfc.figure.u.53"></div><pre class="inline"><span id="rfc.iref.g.86"></span><span id="rfc.iref.g.87"></span>  <a href="#header.te" class="smpl">TE</a>        = "TE" ":" #( <a href="#header.te" class="smpl">t-codings</a> )
     1654      <div id="rfc.figure.u.50"></div><pre class="inline"><span id="rfc.iref.g.86"></span><span id="rfc.iref.g.87"></span>  <a href="#header.te" class="smpl">TE</a>        = "TE" ":" #( <a href="#header.te" class="smpl">t-codings</a> )
    16741655  <a href="#header.te" class="smpl">t-codings</a> = "trailers" / ( <a href="#transfer.codings" class="smpl">transfer-extension</a> [ <a href="#abnf.dependencies" class="smpl">accept-params</a> ] )
    16751656</pre><p id="rfc.section.8.5.p.3">The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked transfer-coding,
    … …  
    16771658      </p>
    16781659      <p id="rfc.section.8.5.p.4">Examples of its use are:</p>
    1679       <div id="rfc.figure.u.54"></div><pre class="text">    TE: deflate
     1660      <div id="rfc.figure.u.51"></div><pre class="text">    TE: deflate
    16801661    TE:
    16811662    TE: trailers, deflate;q=0.5
    … …  
    17141695         with chunked transfer-coding.
    17151696      </p>
    1716       <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.88"></span>  <a href="#header.trailer" class="smpl">Trailer</a>  = "Trailer" ":" 1#<a href="#message.headers" class="smpl">field-name</a>
     1697      <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.88"></span>  <a href="#header.trailer" class="smpl">Trailer</a>  = "Trailer" ":" 1#<a href="#message.headers" class="smpl">field-name</a>
    17171698</pre><p id="rfc.section.8.6.p.3">An HTTP/1.1 message <em class="bcp14">SHOULD</em> include a Trailer header field in a message using chunked transfer-coding with a non-empty trailer. Doing so allows the recipient
    17181699         to know which header fields to expect in the trailer.
    … …  
    17341715         transfer-coding is a property of the message, not of the entity.
    17351716      </p>
    1736       <div id="rfc.figure.u.56"></div><pre class="inline"><span id="rfc.iref.g.89"></span>  <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>       = "Transfer-Encoding" ":" 1#<a href="#transfer.codings" class="smpl">transfer-coding</a>
     1717      <div id="rfc.figure.u.53"></div><pre class="inline"><span id="rfc.iref.g.89"></span>  <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>       = "Transfer-Encoding" ":" 1#<a href="#transfer.codings" class="smpl">transfer-coding</a>
    17371718</pre><p id="rfc.section.8.7.p.3">Transfer-codings are defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;3.3</a>. An example is:
    17381719      </p>
    1739       <div id="rfc.figure.u.57"></div><pre class="text">  Transfer-Encoding: chunked
     1720      <div id="rfc.figure.u.54"></div><pre class="text">  Transfer-Encoding: chunked
    17401721</pre><p id="rfc.section.8.7.p.5">If multiple encodings have been applied to an entity, the transfer-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 entity-header fields not defined by this specification.
    17411722      </p>
    … …  
    17471728         to use if the server finds it appropriate to switch protocols. The server <em class="bcp14">MUST</em> use the Upgrade header field within a 101 (Switching Protocols) response to indicate which protocol(s) are being switched.
    17481729      </p>
    1749       <div id="rfc.figure.u.58"></div><pre class="inline"><span id="rfc.iref.g.90"></span>  <a href="#header.upgrade" class="smpl">Upgrade</a>        = "Upgrade" ":" 1#<a href="#product.tokens" class="smpl">product</a>
     1730      <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.90"></span>  <a href="#header.upgrade" class="smpl">Upgrade</a>        = "Upgrade" ":" 1#<a href="#product.tokens" class="smpl">product</a>
    17501731</pre><p id="rfc.section.8.8.p.3">For example,</p>
    1751       <div id="rfc.figure.u.59"></div><pre class="text">    Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
     1732      <div id="rfc.figure.u.56"></div><pre class="text">    Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
    17521733</pre><p id="rfc.section.8.8.p.5">The Upgrade header field is intended to provide a simple mechanism for transition from HTTP/1.1 to some other, incompatible
    17531734         protocol. It does so by allowing the client to advertise its desire to use another protocol, such as a later version of HTTP
    … …  
    17781759         of all senders along the request/response chain.
    17791760      </p>
    1780       <div id="rfc.figure.u.60"></div><pre class="inline"><span id="rfc.iref.g.91"></span><span id="rfc.iref.g.92"></span><span id="rfc.iref.g.93"></span><span id="rfc.iref.g.94"></span><span id="rfc.iref.g.95"></span><span id="rfc.iref.g.96"></span>  <a href="#header.via" class="smpl">Via</a> =  "Via" ":" 1#( <a href="#header.via" class="smpl">received-protocol</a> <a href="#header.via" class="smpl">received-by</a> [ <a href="#rule.comment" class="smpl">comment</a> ] )
     1761      <div id="rfc.figure.u.57"></div><pre class="inline"><span id="rfc.iref.g.91"></span><span id="rfc.iref.g.92"></span><span id="rfc.iref.g.93"></span><span id="rfc.iref.g.94"></span><span id="rfc.iref.g.95"></span><span id="rfc.iref.g.96"></span>  <a href="#header.via" class="smpl">Via</a> =  "Via" ":" 1#( <a href="#header.via" class="smpl">received-protocol</a> <a href="#header.via" class="smpl">received-by</a> [ <a href="#rule.comment" class="smpl">comment</a> ] )
    17811762  <a href="#header.via" class="smpl">received-protocol</a> = [ <a href="#header.via" class="smpl">protocol-name</a> "/" ] <a href="#header.via" class="smpl">protocol-version</a>
    17821763  <a href="#header.via" class="smpl">protocol-name</a>     = <a href="#rule.token.separators" class="smpl">token</a>
    … …  
    18011782         server at www.example.com. The request received by www.example.com would then have the following Via header field:
    18021783      </p>
    1803       <div id="rfc.figure.u.61"></div><pre class="text">    Via: 1.0 fred, 1.1 p.example.net (Apache/1.1)
     1784      <div id="rfc.figure.u.58"></div><pre class="text">    Via: 1.0 fred, 1.1 p.example.net (Apache/1.1)
    18041785</pre><p id="rfc.section.8.9.p.9">Proxies and gateways used as a portal through a network firewall <em class="bcp14">SHOULD NOT</em>, by default, forward the names and ports of hosts within the firewall region. This information <em class="bcp14">SHOULD</em> only be propagated if explicitly enabled. If not enabled, the received-by host of any host behind the firewall <em class="bcp14">SHOULD</em> be replaced by an appropriate pseudonym for that host.
    18051786      </p>
    … …  
    18071788         For example,
    18081789      </p>
    1809       <div id="rfc.figure.u.62"></div><pre class="text">    Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy
     1790      <div id="rfc.figure.u.59"></div><pre class="text">    Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy
    18101791</pre><p id="rfc.section.8.9.p.12">could be collapsed to</p>
    1811       <div id="rfc.figure.u.63"></div><pre class="text">    Via: 1.0 ricky, 1.1 mertz, 1.0 lucy
     1792      <div id="rfc.figure.u.60"></div><pre class="text">    Via: 1.0 ricky, 1.1 mertz, 1.0 lucy
    18121793</pre><p id="rfc.section.8.9.p.14">Applications <em class="bcp14">SHOULD NOT</em> combine multiple entries unless they are all under the same organizational control and the hosts have already been replaced
    18131794         by pseudonyms. Applications <em class="bcp14">MUST NOT</em> combine entries which have different received-protocol values.
    … …  
    21062087         them for the discovery of many of the problems that this document attempts to rectify.
    21072088      </p>
    2108       <p id="rfc.section.11.p.7">This specification makes heavy use of the augmented BNF and generic constructs defined by David H. Crocker for <a href="#RFC5234" id="rfc.xref.RFC5234.3"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Similarly, it reuses many of the definitions provided by Nathaniel Borenstein and Ned Freed for MIME <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>. We hope that their inclusion in this specification will help reduce past confusion over the relationship between HTTP and
     2089      <p id="rfc.section.11.p.7">This specification makes heavy use of the augmented BNF and generic constructs defined by David H. Crocker for <a href="#RFC5234" id="rfc.xref.RFC5234.4"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Similarly, it reuses many of the definitions provided by Nathaniel Borenstein and Ned Freed for MIME <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>. We hope that their inclusion in this specification will help reduce past confusion over the relationship between HTTP and
    21092090         Internet mail message formats.
    21102091      </p>
    … …  
    27712752                     <ul class="ind">
    27722753                        <li class="indline1"><tt>absolute-URI</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.25"><b>2.1</b></a></li>
    2773                         <li class="indline1"><tt>ALPHA</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.3"><b>1.2</b></a></li>
     2754                        <li class="indline1">ALPHA&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.1"><b>1.2</b></a></li>
    27742755                        <li class="indline1"><tt>asctime-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.38"><b>3.2.1</b></a></li>
    27752756                        <li class="indline1"><tt>attribute</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.49"><b>3.3</b></a></li>
    27762757                        <li class="indline1"><tt>authority</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.26"><b>2.1</b></a></li>
    2777                         <li class="indline1"><tt>CHAR</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.2"><b>1.2</b></a></li>
     2758                        <li class="indline1">CHAR&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.2"><b>1.2</b></a></li>
    27782759                        <li class="indline1"><tt>chunk</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.52"><b>3.3.1</b></a></li>
    27792760                        <li class="indline1"><tt>chunk-data</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.58"><b>3.3.1</b></a></li>
    … …  
    27872768                        <li class="indline1"><tt>connection-token</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.82"><b>8.1</b></a></li>
    27882769                        <li class="indline1"><tt>Content-Length</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.83"><b>8.2</b></a></li>
    2789                         <li class="indline1"><tt>CR</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.6"><b>1.2</b></a></li>
    2790                         <li class="indline1"><tt>CRLF</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.11"><b>1.2.2</b></a></li>
     2770                        <li class="indline1">CR&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.3"><b>1.2</b></a></li>
     2771                        <li class="indline1">CRLF&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.4"><b>1.2</b></a></li>
    27912772                        <li class="indline1"><tt>ctext</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.19"><b>1.2.2</b></a></li>
    2792                         <li class="indline1"><tt>CTL</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.5"><b>1.2</b></a></li>
     2773                        <li class="indline1">CTL&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.5"><b>1.2</b></a></li>
    27932774                        <li class="indline1"><tt>Date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.84"><b>8.3</b></a></li>
    27942775                        <li class="indline1"><tt>date1</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.39"><b>3.2.1</b></a></li>
    27952776                        <li class="indline1"><tt>date2</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.40"><b>3.2.1</b></a></li>
    27962777                        <li class="indline1"><tt>date3</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.41"><b>3.2.1</b></a></li>
    2797                         <li class="indline1"><tt>DIGIT</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.4"><b>1.2</b></a></li>
    2798                         <li class="indline1"><tt>DQUOTE</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.10"><b>1.2</b></a></li>
     2778                        <li class="indline1">DIGIT&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.6"><b>1.2</b></a></li>
     2779                        <li class="indline1">DQUOTE&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.7"><b>1.2</b></a></li>
    27992780                        <li class="indline1"><tt>extension-code</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.79"><b>6.1.1</b></a></li>
    28002781                        <li class="indline1"><tt>extension-method</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.74"><b>5.1.1</b></a></li>
    … …  
    28042785                        <li class="indline1"><tt>general-header</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.70"><b>4.5</b></a></li>
    28052786                        <li class="indline1"><tt>generic-message</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.63"><b>4.1</b></a></li>
    2806                         <li class="indline1"><tt>HEXDIG</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.14"><b>1.2.2</b></a></li>
     2787                        <li class="indline1">HEXDIG&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.8"><b>1.2</b></a></li>
    28072788                        <li class="indline1"><tt>Host</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.85"><b>8.4</b></a></li>
    2808                         <li class="indline1"><tt>HTAB</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.9"><b>1.2</b></a></li>
     2789                        <li class="indline1">HTAB&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.9"><b>1.2</b></a></li>
    28092790                        <li class="indline1"><tt>HTTP-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.34"><b>3.2.1</b></a></li>
    28102791                        <li class="indline1"><tt>HTTP-message</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.62"><b>4.1</b></a></li>
    … …  
    28132794                        <li class="indline1"><tt>HTTP-Version</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.32"><b>3.1</b></a></li>
    28142795                        <li class="indline1"><tt>last-chunk</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.54"><b>3.3.1</b></a></li>
    2815                         <li class="indline1"><tt>LF</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.7"><b>1.2</b></a></li>
    2816                         <li class="indline1"><tt>LWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.12"><b>1.2.2</b></a></li>
     2796                        <li class="indline1">LF&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.10"><b>1.2</b></a></li>
     2797                        <li class="indline1"><tt>LWS</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.13"><b>1.2.2</b></a></li>
    28172798                        <li class="indline1"><tt>message-body</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.69"><b>4.3</b></a></li>
    28182799                        <li class="indline1"><tt>message-header</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.65"><b>4.2</b></a></li>
    … …  
    28202801                        <li class="indline1"><tt>month</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.45"><b>3.2.1</b></a></li>
    28212802                        <li class="indline1"><tt>obsolete-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.36"><b>3.2.1</b></a></li>
    2822                         <li class="indline1"><tt>OCTET</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.1"><b>1.2</b></a></li>
     2803                        <li class="indline1">OCTET&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.11"><b>1.2</b></a></li>
    28232804                        <li class="indline1"><tt>parameter</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.48"><b>3.3</b></a></li>
    28242805                        <li class="indline1"><tt>path-absolute</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.27"><b>2.1</b></a></li>
    … …  
    28442825                        <li class="indline1"><tt>rfc850-date</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.37"><b>3.2.1</b></a></li>
    28452826                        <li class="indline1"><tt>separators</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.17"><b>1.2.2</b></a></li>
    2846                         <li class="indline1"><tt>SP</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.8"><b>1.2</b></a></li>
     2827                        <li class="indline1">SP&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.12"><b>1.2</b></a></li>
    28472828                        <li class="indline1"><tt>start-line</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.64"><b>4.1</b></a></li>
    28482829                        <li class="indline1"><tt>Status-Code</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.78"><b>6.1.1</b></a></li>
    … …  
    28512832                        <li class="indline1"><tt>tchar</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.16"><b>1.2.2</b></a></li>
    28522833                        <li class="indline1"><tt>TE</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.86"><b>8.5</b></a></li>
    2853                         <li class="indline1"><tt>TEXT</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.13"><b>1.2.2</b></a></li>
     2834                        <li class="indline1"><tt>TEXT</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.14"><b>1.2.2</b></a></li>
    28542835                        <li class="indline1"><tt>time</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.42"><b>3.2.1</b></a></li>
    28552836                        <li class="indline1"><tt>token</tt>&nbsp;&nbsp;<a class="iref" href="#rfc.iref.g.15"><b>1.2.2</b></a></li>
    … …  
    29952976                  <li class="indline1"><em>RFC4288</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC4288.1">9.3</a>, <a class="iref" href="#RFC4288"><b>12.2</b></a></li>
    29962977                  <li class="indline1"><em>RFC4395</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC4395.1">9.2</a>, <a class="iref" href="#RFC4395"><b>12.2</b></a></li>
    2997                   <li class="indline1"><em>RFC5234</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.1">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.2">1.2.1</a>, <a class="iref" href="#rfc.xref.RFC5234.3">11</a>, <a class="iref" href="#RFC5234"><b>12.1</b></a></li>
     2978                  <li class="indline1"><em>RFC5234</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.1">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.2">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.3">1.2.1</a>, <a class="iref" href="#rfc.xref.RFC5234.4">11</a>, <a class="iref" href="#RFC5234"><b>12.1</b></a><ul class="ind">
     2979                        <li class="indline1"><em>Appendix B.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5234.2">1.2</a></li>
     2980                     </ul>
     2981                  </li>
    29982982                  <li class="indline1"><em>RFC5322</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.1">1</a>, <a class="iref" href="#rfc.xref.RFC5322.2">4.1</a>, <a class="iref" href="#rfc.xref.RFC5322.3">4.2</a>, <a class="iref" href="#rfc.xref.RFC5322.4">8.3</a>, <a class="iref" href="#rfc.xref.RFC5322.5">8.9</a>, <a class="iref" href="#RFC5322"><b>12.2</b></a><ul class="ind">
    29992983                        <li class="indline1"><em>Section 2.1</em>&nbsp;&nbsp;<a class="iref" href="#rfc.xref.RFC5322.3">4.2</a></li>
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