Changeset 1431


Ignore:
Timestamp:
Sep 1, 2011, 5:24:29 PM (8 years ago)
Author:
fielding@…
Message:

(editorial) rearrange some sections for better readability and
adjust some of the headings.

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

Legend:

Unmodified
Added
Removed

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

    r1427 r1431  
    382382      <link rel="Index" href="#rfc.index">
    383383      <link rel="Chapter" title="1 Introduction" href="#rfc.section.1">
    384       <link rel="Chapter" title="2 HTTP-related architecture" href="#rfc.section.2">
     384      <link rel="Chapter" title="2 Architecture" href="#rfc.section.2">
    385385      <link rel="Chapter" title="3 Message Format" href="#rfc.section.3">
    386386      <link rel="Chapter" title="4 Request" href="#rfc.section.4">
    … …  
    554554            </ul>
    555555         </li>
    556          <li>2.&nbsp;&nbsp;&nbsp;<a href="#architecture">HTTP-related architecture</a><ul>
     556         <li>2.&nbsp;&nbsp;&nbsp;<a href="#architecture">Architecture</a><ul>
    557557               <li>2.1&nbsp;&nbsp;&nbsp;<a href="#operation">Client/Server Messaging</a></li>
    558558               <li>2.2&nbsp;&nbsp;&nbsp;<a href="#message-orientation-and-buffering">Message Orientation and Buffering</a></li>
    … …  
    570570         </li>
    571571         <li>3.&nbsp;&nbsp;&nbsp;<a href="#http.message">Message Format</a><ul>
    572                <li>3.1&nbsp;&nbsp;&nbsp;<a href="#message.robustness">Message Parsing and Robustness</a></li>
     572               <li>3.1&nbsp;&nbsp;&nbsp;<a href="#start.line">Start Line</a></li>
    573573               <li>3.2&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Fields</a><ul>
    574574                     <li>3.2.1&nbsp;&nbsp;&nbsp;<a href="#field.parsing">Field Parsing</a></li>
    … …  
    578578               </li>
    579579               <li>3.3&nbsp;&nbsp;&nbsp;<a href="#message.body">Message Body</a></li>
    580                <li>3.4&nbsp;&nbsp;&nbsp;<a href="#incomplete.messages">Incomplete Messages</a></li>
    581                <li>3.5&nbsp;&nbsp;&nbsp;<a href="#general.header.fields">General Header Fields</a></li>
     580               <li>3.4&nbsp;&nbsp;&nbsp;<a href="#incomplete.messages">Handling Incomplete Messages</a></li>
     581               <li>3.5&nbsp;&nbsp;&nbsp;<a href="#message.robustness">Message Parsing Robustness</a></li>
    582582            </ul>
    583583         </li>
    … …  
    853853                 ; obsolete line folding
    854854                 ; see <a href="#field.parsing" title="Field Parsing">Section&nbsp;3.2.1</a>
    855 </pre><h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="architecture" href="#architecture">HTTP-related architecture</a></h1>
     855</pre><h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="architecture" href="#architecture">Architecture</a></h1>
    856856      <p id="rfc.section.2.p.1">HTTP was created for the World Wide Web architecture and has evolved over time to support the scalability needs of a worldwide
    857857         hypertext system. Much of that architecture is reflected in the terminology and syntax productions used to define HTTP.
    … …  
    11721172         the end of the header section, and an optional message-body.
    11731173      </p>
    1174       <p id="rfc.section.3.p.2">An HTTP message can either be a request from client to server or a response from server to client. Syntactically, the two
     1174      <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.28"></span>  <a href="#http.message" class="smpl">HTTP-message</a>    = <a href="#http.message" class="smpl">start-line</a>
     1175                    *( <a href="#header.fields" class="smpl">header-field</a> <a href="#core.rules" class="smpl">CRLF</a> )
     1176                    <a href="#core.rules" class="smpl">CRLF</a>
     1177                    [ <a href="#message.body" class="smpl">message-body</a> ]
     1178</pre><p id="rfc.section.3.p.3">The normal procedure for parsing an HTTP message is to read the start-line into a structure, read each header field into a
     1179         hash table by field name until the empty line, and then use the parsed data to determine if a message-body is expected. If
     1180         a message-body has been indicated, then it is read as a stream until an amount of octets equal to the message-body length
     1181         is read or the connection is closed.
     1182      </p>
     1183      <p id="rfc.section.3.p.4">Recipients <em class="bcp14">MUST</em> parse an HTTP message as a sequence of octets in an encoding that is a superset of US-ASCII <a href="#USASCII" id="rfc.xref.USASCII.2"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a>. Parsing an HTTP message as a stream of Unicode characters, without regard for the specific encoding, creates security vulnerabilities
     1184         due to the varying ways that string processing libraries handle invalid multibyte character sequences that contain the octet
     1185         LF (%x0A). String-based parsers can only be safely used within protocol elements after the element has been extracted from
     1186         the message, such as within a header field-value after message parsing has delineated the individual fields.
     1187      </p>
     1188      <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="start.line" href="#start.line">Start Line</a></h2>
     1189      <p id="rfc.section.3.1.p.1">An HTTP message can either be a request from client to server or a response from server to client. Syntactically, the two
    11751190         types of message differ only in the start-line, which is either a Request-Line (for requests) or a Status-Line (for responses),
    11761191         and in the algorithm for determining the length of the message-body (<a href="#message.body" title="Message Body">Section&nbsp;3.3</a>). In theory, a client could receive requests and a server could receive responses, distinguishing them by their different
    … …  
    11781193         or invalid request method) and clients are implemented to only expect a response.
    11791194      </p>
    1180       <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.28"></span>  <a href="#http.message" class="smpl">HTTP-message</a>    = <a href="#http.message" class="smpl">start-line</a>
    1181                     *( <a href="#header.fields" class="smpl">header-field</a> <a href="#core.rules" class="smpl">CRLF</a> )
    1182                     <a href="#core.rules" class="smpl">CRLF</a>
    1183                     [ <a href="#message.body" class="smpl">message-body</a> ]
    1184   <a href="#http.message" class="smpl">start-line</a>      = <a href="#request-line" class="smpl">Request-Line</a> / <a href="#status-line" class="smpl">Status-Line</a>
    1185 </pre><p id="rfc.section.3.p.4">Implementations <em class="bcp14">MUST NOT</em> send whitespace between the start-line and the first header field. The presence of such whitespace in a request might be an
     1195      <div id="rfc.figure.u.20"></div><pre class="inline"><span id="rfc.iref.g.29"></span>  <a href="#http.message" class="smpl">start-line</a>      = <a href="#request-line" class="smpl">Request-Line</a> / <a href="#status-line" class="smpl">Status-Line</a>
     1196</pre><p id="rfc.section.3.1.p.4">Implementations <em class="bcp14">MUST NOT</em> send whitespace between the start-line and the first header field. The presence of such whitespace in a request might be an
    11861197         attempt to trick a server into ignoring that field or processing the line after it as a new request, either of which might
    11871198         result in a security vulnerability if other implementations within the request chain interpret the same message differently.
    11881199         Likewise, the presence of such whitespace in a response might be ignored by some clients or cause others to cease parsing.
    11891200      </p>
    1190       <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="message.robustness" href="#message.robustness">Message Parsing and Robustness</a></h2>
    1191       <p id="rfc.section.3.1.p.1">The normal procedure for parsing an HTTP message is to read the start-line into a structure, read each header field into a
    1192          hash table by field name until the empty line, and then use the parsed data to determine if a message-body is expected. If
    1193          a message-body has been indicated, then it is read as a stream until an amount of octets equal to the message-body length
    1194          is read or the connection is closed.
    1195       </p>
    1196       <p id="rfc.section.3.1.p.2">Recipients <em class="bcp14">MUST</em> parse an HTTP message as a sequence of octets in an encoding that is a superset of US-ASCII <a href="#USASCII" id="rfc.xref.USASCII.2"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a>. Parsing an HTTP message as a stream of Unicode characters, without regard for the specific encoding, creates security vulnerabilities
    1197          due to the varying ways that string processing libraries handle invalid multibyte character sequences that contain the octet
    1198          LF (%x0A). String-based parsers can only be safely used within protocol elements after the element has been extracted from
    1199          the message, such as within a header field-value after message parsing has delineated the individual fields.
    1200       </p>
    1201       <p id="rfc.section.3.1.p.3">Older HTTP/1.0 client implementations might send an extra CRLF after a POST request as a lame workaround for some early server
    1202          applications that failed to read message-body content that was not terminated by a line-ending. An HTTP/1.1 client <em class="bcp14">MUST NOT</em> preface or follow a request with an extra CRLF. If terminating the request message-body with a line-ending is desired, then
    1203          the client <em class="bcp14">MUST</em> include the terminating CRLF octets as part of the message-body length.
    1204       </p>
    1205       <p id="rfc.section.3.1.p.4">In the interest of robustness, servers <em class="bcp14">SHOULD</em> ignore at least one empty line received where a Request-Line is expected. In other words, if the server is reading the protocol
    1206          stream at the beginning of a message and receives a CRLF first, it <em class="bcp14">SHOULD</em> ignore the CRLF. Likewise, although the line terminator for the start-line and header fields is the sequence CRLF, we recommend
    1207          that recipients recognize a single LF as a line terminator and ignore any CR.
    1208       </p>
    1209       <p id="rfc.section.3.1.p.5">When a server listening only for HTTP request messages, or processing what appears from the start-line to be an HTTP request
    1210          message, receives a sequence of octets that does not match the HTTP-message grammar aside from the robustness exceptions listed
    1211          above, the server <em class="bcp14">MUST</em> respond with an HTTP/1.1 400 (Bad Request) response.
    1212       </p>
    12131201      <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a>&nbsp;<a id="header.fields" href="#header.fields">Header Fields</a></h2>
    12141202      <p id="rfc.section.3.2.p.1">Each HTTP header field consists of a case-insensitive field name followed by a colon (":"), optional whitespace, and the field
    12151203         value.
    12161204      </p>
    1217       <div id="rfc.figure.u.20"></div><pre class="inline"><span id="rfc.iref.g.29"></span><span id="rfc.iref.g.30"></span><span id="rfc.iref.g.31"></span><span id="rfc.iref.g.32"></span>  <a href="#header.fields" class="smpl">header-field</a>   = <a href="#header.fields" class="smpl">field-name</a> ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.fields" class="smpl">field-value</a> <a href="#rule.whitespace" class="smpl">BWS</a>
     1205      <div id="rfc.figure.u.21"></div><pre class="inline"><span id="rfc.iref.g.30"></span><span id="rfc.iref.g.31"></span><span id="rfc.iref.g.32"></span><span id="rfc.iref.g.33"></span>  <a href="#header.fields" class="smpl">header-field</a>   = <a href="#header.fields" class="smpl">field-name</a> ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.fields" class="smpl">field-value</a> <a href="#rule.whitespace" class="smpl">BWS</a>
    12181206  <a href="#header.fields" class="smpl">field-name</a>     = <a href="#rule.token.separators" class="smpl">token</a>
    12191207  <a href="#header.fields" class="smpl">field-value</a>    = *( <a href="#header.fields" class="smpl">field-content</a> / <a href="#rule.whitespace" class="smpl">obs-fold</a> )
    … …  
    12761264         </p>
    12771265      </div>
    1278       <div id="rfc.figure.u.21"></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>  <a href="#rule.token.separators" class="smpl">word</a>           = <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a>
     1266      <div id="rfc.figure.u.22"></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>  <a href="#rule.token.separators" class="smpl">word</a>           = <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a>
    12791267
    12801268  <a href="#rule.token.separators" class="smpl">token</a>          = 1*<a href="#rule.token.separators" class="smpl">tchar</a>
    … …  
    12911279         <p id="rfc.section.3.2.3.p.3">      A string of text is parsed as a single word if it is quoted using double-quote marks.</p>
    12921280      </div>
    1293       <div id="rfc.figure.u.22"></div><pre class="inline"><span id="rfc.iref.g.37"></span><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></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>
     1281      <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span><span id="rfc.iref.g.40"></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>
    12941282  <a href="#rule.quoted-string" class="smpl">qdtext</a>         = <a href="#rule.whitespace" class="smpl">OWS</a> / %x21 / %x23-5B / %x5D-7E / <a href="#rule.quoted-string" class="smpl">obs-text</a>
    12951283  <a href="#rule.quoted-string" class="smpl">obs-text</a>       = %x80-FF
    … …  
    12971285         <p id="rfc.section.3.2.3.p.5">  The backslash octet ("\") can be used as a single-octet quoting mechanism within quoted-string constructs:</p>
    12981286      </div>
    1299       <div id="rfc.figure.u.23"></div><pre class="inline"><span id="rfc.iref.g.40"></span>  <a href="#rule.quoted-pair" class="smpl">quoted-pair</a>    = "\" ( <a href="#core.rules" class="smpl">HTAB</a> /<a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> )
     1287      <div id="rfc.figure.u.24"></div><pre class="inline"><span id="rfc.iref.g.41"></span>  <a href="#rule.quoted-pair" class="smpl">quoted-pair</a>    = "\" ( <a href="#core.rules" class="smpl">HTAB</a> /<a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> )
    13001288</pre><p id="rfc.section.3.2.3.p.7">Recipients that process the value of the quoted-string <em class="bcp14">MUST</em> handle a quoted-pair as if it were replaced by the octet following the backslash.
    13011289      </p>
    … …  
    13071295         </p>
    13081296      </div>
    1309       <div id="rfc.figure.u.24"></div><pre class="inline"><span id="rfc.iref.g.41"></span><span id="rfc.iref.g.42"></span>  <a href="#rule.comment" class="smpl">comment</a>        = "(" *( <a href="#rule.comment" class="smpl">ctext</a> / <a href="#rule.quoted-cpair" class="smpl">quoted-cpair</a> / <a href="#rule.comment" class="smpl">comment</a> ) ")"
     1297      <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.42"></span><span id="rfc.iref.g.43"></span>  <a href="#rule.comment" class="smpl">comment</a>        = "(" *( <a href="#rule.comment" class="smpl">ctext</a> / <a href="#rule.quoted-cpair" class="smpl">quoted-cpair</a> / <a href="#rule.comment" class="smpl">comment</a> ) ")"
    13101298  <a href="#rule.comment" class="smpl">ctext</a>          = <a href="#rule.whitespace" class="smpl">OWS</a> / %x21-27 / %x2A-5B / %x5D-7E / <a href="#rule.quoted-string" class="smpl">obs-text</a>
    13111299</pre><div id="rule.quoted-cpair">
    13121300         <p id="rfc.section.3.2.3.p.11">  The backslash octet ("\") can be used as a single-octet quoting mechanism within comment constructs:</p>
    13131301      </div>
    1314       <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.43"></span>  <a href="#rule.quoted-cpair" class="smpl">quoted-cpair</a>    = "\" ( <a href="#core.rules" class="smpl">HTAB</a> /<a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> )
     1302      <div id="rfc.figure.u.26"></div><pre class="inline"><span id="rfc.iref.g.44"></span>  <a href="#rule.quoted-cpair" class="smpl">quoted-cpair</a>    = "\" ( <a href="#core.rules" class="smpl">HTAB</a> /<a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> )
    13151303</pre><p id="rfc.section.3.2.3.p.13">Senders <em class="bcp14">SHOULD NOT</em> escape octets in comments that do not require escaping (i.e., other than the backslash octet "\" and the parentheses "(" and
    13161304         ")").
    … …  
    13181306      <h2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a>&nbsp;<a id="message.body" href="#message.body">Message Body</a></h2>
    13191307      <p id="rfc.section.3.3.p.1">The message-body (if any) of an HTTP message is used to carry the payload body associated with the request or response.</p>
    1320       <div id="rfc.figure.u.26"></div><pre class="inline"><span id="rfc.iref.g.44"></span>  <a href="#message.body" class="smpl">message-body</a> = *OCTET
     1308      <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.45"></span>  <a href="#message.body" class="smpl">message-body</a> = *OCTET
    13211309</pre><p id="rfc.section.3.3.p.3">The message-body differs from the payload body only when a transfer-coding has been applied, as indicated by the Transfer-Encoding
    13221310         header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.1" title="Transfer-Encoding">Section&nbsp;9.7</a>). 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.
    … …  
    14001388         knowledge can be in the form of specific user configuration or by remembering the version of a prior received response.
    14011389      </p>
    1402       <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a>&nbsp;<a id="incomplete.messages" href="#incomplete.messages">Incomplete Messages</a></h2>
     1390      <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a>&nbsp;<a id="incomplete.messages" href="#incomplete.messages">Handling Incomplete Messages</a></h2>
    14031391      <p id="rfc.section.3.4.p.1">Request messages that are prematurely terminated, possibly due to a cancelled connection or a server-imposed time-out exception, <em class="bcp14">MUST</em> result in closure of the connection; sending an HTTP/1.1 error response prior to closing the connection is <em class="bcp14">OPTIONAL</em>.
    14041392      </p>
    … …  
    14201408         requests on a connection is described in <a href="#pipelining" title="Pipelining">Section&nbsp;7.1.2.2</a>.
    14211409      </p>
    1422       <h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a>&nbsp;<a id="general.header.fields" href="#general.header.fields">General Header Fields</a></h2>
    1423       <p id="rfc.section.3.5.p.1">There are a few header fields which have general applicability for both request and response messages, but which do not apply
    1424          to the payload being transferred. These header fields apply only to the message being transmitted.
    1425       </p>
    1426       <div id="rfc.table.u.1">
    1427          <table class="tt full left" cellpadding="3" cellspacing="0">
    1428             <thead>
    1429                <tr>
    1430                   <th>Header Field Name</th>
    1431                   <th>Defined in...</th>
    1432                </tr>
    1433             </thead>
    1434             <tbody>
    1435                <tr>
    1436                   <td class="left">Connection</td>
    1437                   <td class="left"><a href="#header.connection" id="rfc.xref.header.connection.4" title="Connection">Section&nbsp;9.1</a></td>
    1438                </tr>
    1439                <tr>
    1440                   <td class="left">Date</td>
    1441                   <td class="left"><a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;9.3</a></td>
    1442                </tr>
    1443                <tr>
    1444                   <td class="left">Trailer</td>
    1445                   <td class="left"><a href="#header.trailer" id="rfc.xref.header.trailer.1" title="Trailer">Section&nbsp;9.6</a></td>
    1446                </tr>
    1447                <tr>
    1448                   <td class="left">Transfer-Encoding</td>
    1449                   <td class="left"><a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section&nbsp;9.7</a></td>
    1450                </tr>
    1451                <tr>
    1452                   <td class="left">Upgrade</td>
    1453                   <td class="left"><a href="#header.upgrade" id="rfc.xref.header.upgrade.1" title="Upgrade">Section&nbsp;9.8</a></td>
    1454                </tr>
    1455                <tr>
    1456                   <td class="left">Via</td>
    1457                   <td class="left"><a href="#header.via" id="rfc.xref.header.via.2" title="Via">Section&nbsp;9.9</a></td>
    1458                </tr>
    1459             </tbody>
    1460          </table>
    1461       </div>
     1410      <h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a>&nbsp;<a id="message.robustness" href="#message.robustness">Message Parsing Robustness</a></h2>
     1411      <p id="rfc.section.3.5.p.1">Older HTTP/1.0 client implementations might send an extra CRLF after a POST request as a lame workaround for some early server
     1412         applications that failed to read message-body content that was not terminated by a line-ending. An HTTP/1.1 client <em class="bcp14">MUST NOT</em> preface or follow a request with an extra CRLF. If terminating the request message-body with a line-ending is desired, then
     1413         the client <em class="bcp14">MUST</em> include the terminating CRLF octets as part of the message-body length.
     1414      </p>
     1415      <p id="rfc.section.3.5.p.2">In the interest of robustness, servers <em class="bcp14">SHOULD</em> ignore at least one empty line received where a Request-Line is expected. In other words, if the server is reading the protocol
     1416         stream at the beginning of a message and receives a CRLF first, it <em class="bcp14">SHOULD</em> ignore the CRLF. Likewise, although the line terminator for the start-line and header fields is the sequence CRLF, we recommend
     1417         that recipients recognize a single LF as a line terminator and ignore any CR.
     1418      </p>
     1419      <p id="rfc.section.3.5.p.3">When a server listening only for HTTP request messages, or processing what appears from the start-line to be an HTTP request
     1420         message, receives a sequence of octets that does not match the HTTP-message grammar aside from the robustness exceptions listed
     1421         above, the server <em class="bcp14">MUST</em> respond with an HTTP/1.1 400 (Bad Request) response.
     1422      </p>
    14621423      <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="request" href="#request">Request</a></h1>
    14631424      <p id="rfc.section.4.p.1">A request message from a client to a server begins with a Request-Line, followed by zero or more header fields, an empty line
    14641425         signifying the end of the header block, and an optional message body.
    14651426      </p>
    1466       <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.45"></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;4.1</a>
     1427      <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.46"></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;4.1</a>
    14671428                  *( <a href="#header.fields" class="smpl">header-field</a> <a href="#core.rules" class="smpl">CRLF</a> )    ; <a href="#header.fields" title="Header Fields">Section&nbsp;3.2</a>
    14681429                  <a href="#core.rules" class="smpl">CRLF</a>
    … …  
    14721433         the protocol version, and ending with CRLF.
    14731434      </p>
    1474       <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.46"></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-target" class="smpl">request-target</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>
     1435      <div id="rfc.figure.u.29"></div><pre class="inline"><span id="rfc.iref.g.47"></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-target" class="smpl">request-target</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>
    14751436</pre><h3 id="rfc.section.4.1.1"><a href="#rfc.section.4.1.1">4.1.1</a>&nbsp;<a id="method" href="#method">Method</a></h3>
    14761437      <p id="rfc.section.4.1.1.p.1">The Method token indicates the request method to be performed on the target resource. The request method is case-sensitive.</p>
    1477       <div id="rfc.figure.u.29"></div><pre class="inline"><span id="rfc.iref.g.47"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#rule.token.separators" class="smpl">token</a>
     1438      <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.48"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#rule.token.separators" class="smpl">token</a>
    14781439</pre><p id="rfc.section.4.1.1.p.3">See <a href="p2-semantics.html#method" title="Method">Section 2</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for further information, such as the list of methods defined by this specification, the IANA registry, and considerations
    14791440         for new methods.
    … …  
    14841445         is initiated, all or part of that URI is used to construct the HTTP request-target.
    14851446      </p>
    1486       <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.48"></span>  <a href="#request-target" class="smpl">request-target</a> = "*"
     1447      <div id="rfc.figure.u.31"></div><pre class="inline"><span id="rfc.iref.g.49"></span>  <a href="#request-target" class="smpl">request-target</a> = "*"
    14871448                 / <a href="#uri" class="smpl">absolute-URI</a>
    14881449                 / ( <a href="#uri" class="smpl">path-absolute</a> [ "?" <a href="#uri" class="smpl">query</a> ] )
    … …  
    14921453         process) rather than to a specific named resource at that server. For example,
    14931454      </p>
    1494       <div id="rfc.figure.u.31"></div><pre class="text2">OPTIONS * HTTP/1.1
     1455      <div id="rfc.figure.u.32"></div><pre class="text2">OPTIONS * HTTP/1.1
    14951456</pre><p id="rfc.section.4.1.2.p.6"><span id="rfc.iref.a.3"></span> The "absolute-URI" form is <em class="bcp14">REQUIRED</em> when the request is being made to a proxy. The proxy is requested to either forward the request or service it from a valid
    14961457         cache, and then 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
    … …  
    14981459         address. An example Request-Line would be:
    14991460      </p>
    1500       <div id="rfc.figure.u.32"></div><pre class="text2">GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
     1461      <div id="rfc.figure.u.33"></div><pre class="text2">GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1
    15011462</pre><p id="rfc.section.4.1.2.p.8">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.
    15021463      </p>
    … …  
    15101471         send the lines:
    15111472      </p>
    1512       <div id="rfc.figure.u.33"></div><pre class="text2">GET /pub/WWW/TheProject.html HTTP/1.1
     1473      <div id="rfc.figure.u.34"></div><pre class="text2">GET /pub/WWW/TheProject.html HTTP/1.1
    15131474Host: www.example.org
    15141475</pre><p id="rfc.section.4.1.2.p.13">followed by the remainder of the Request. Note that the origin form of request-target always starts with an absolute path;
    … …  
    15181479         no query component, then the last proxy on the request chain <em class="bcp14">MUST</em> use a request-target of "*" when it forwards the request to the indicated origin server.
    15191480      </p>
    1520       <div id="rfc.figure.u.34"></div>
     1481      <div id="rfc.figure.u.35"></div>
    15211482      <p>For example, the request</p><pre class="text2">OPTIONS http://www.example.org:8001 HTTP/1.1
    1522 </pre><div id="rfc.figure.u.35"></div>
     1483</pre><div id="rfc.figure.u.36"></div>
    15231484      <p>would be forwarded by the final proxy as</p><pre class="text2">OPTIONS * HTTP/1.1
    15241485Host: www.example.org:8001
    … …  
    15901551      </p>
    15911552      <p id="rfc.section.4.3.p.6">Otherwise, when request-target uses the authority form, the effective request URI is undefined.</p>
    1592       <div id="rfc.figure.u.36"></div>
     1553      <div id="rfc.figure.u.37"></div>
    15931554      <p>Example 1: the effective request URI for the message</p>  <pre class="text">GET /pub/WWW/TheProject.html HTTP/1.1
    15941555Host: www.example.org:8080
    … …  
    15961557         the request-target "/pub/WWW/TheProject.html", thus "http://www.example.org:8080/pub/WWW/TheProject.html".
    15971558      </p>
    1598       <div id="rfc.figure.u.37"></div>
     1559      <div id="rfc.figure.u.38"></div>
    15991560      <p>Example 2: the effective request URI for the message</p>  <pre class="text">OPTIONS * HTTP/1.1
    16001561Host: www.example.org
    … …  
    16061567      <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="response" href="#response">Response</a></h1>
    16071568      <p id="rfc.section.5.p.1">After receiving and interpreting a request message, a server responds with an HTTP response message.</p>
    1608       <div id="rfc.figure.u.38"></div><pre class="inline"><span id="rfc.iref.g.49"></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;5.1</a>
     1569      <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.50"></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;5.1</a>
    16091570                  *( <a href="#header.fields" class="smpl">header-field</a> <a href="#core.rules" class="smpl">CRLF</a> )    ; <a href="#header.fields" title="Header Fields">Section&nbsp;3.2</a>
    16101571                  <a href="#core.rules" class="smpl">CRLF</a>
    … …  
    16141575         another space, a possibly-empty textual phrase describing the status code, and ending with CRLF.
    16151576      </p>
    1616       <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.50"></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>
     1577      <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.51"></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>
    16171578</pre><h3 id="rfc.section.5.1.1"><a href="#rfc.section.5.1.1">5.1.1</a>&nbsp;<a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h3>
    16181579      <p id="rfc.section.5.1.1.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request. See <a href="p2-semantics.html#status.code.and.reason.phrase" title="Status Code and Reason Phrase">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.6"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a> for further information, such as the list of status codes defined by this specification, the IANA registry, and considerations
    … …  
    16331594         <li>5xx: Server Error - The server failed to fulfill an apparently valid request</li>
    16341595      </ul>
    1635       <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#core.rules" class="smpl">DIGIT</a>
     1596      <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.52"></span><span id="rfc.iref.g.53"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#core.rules" class="smpl">DIGIT</a>
    16361597  <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a>  = *( <a href="#core.rules" class="smpl">HTAB</a> / <a href="#core.rules" class="smpl">SP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> )
    16371598</pre><h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1>
    … …  
    16401601         a fixed-length subset of that defined by <a href="#RFC1123" id="rfc.xref.RFC1123.1"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>:
    16411602      </p>
    1642       <div id="rfc.figure.u.41"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
     1603      <div id="rfc.figure.u.42"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
    16431604</pre><p id="rfc.section.6.1.p.3">The other formats are described here only for compatibility with obsolete implementations.</p>
    1644       <div id="rfc.figure.u.42"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
     1605      <div id="rfc.figure.u.43"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
    16451606Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
    16461607</pre><p id="rfc.section.6.1.p.5">HTTP/1.1 clients and servers that parse a date value <em class="bcp14">MUST</em> accept all three formats (for compatibility with HTTP/1.0), though they <em class="bcp14">MUST</em> only generate the RFC 1123 format for representing HTTP-date values in header fields.
    … …  
    16501611         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 whitespace beyond that specifically included as SP in the grammar.
    16511612      </p>
    1652       <div id="rfc.figure.u.43"></div><pre class="inline"><span id="rfc.iref.g.53"></span>  <a href="#date.time.formats.full.date" class="smpl">HTTP-date</a>    = <a href="#preferred.date.format" class="smpl">rfc1123-date</a> / <a href="#obsolete.date.formats" class="smpl">obs-date</a>
     1613      <div id="rfc.figure.u.44"></div><pre class="inline"><span id="rfc.iref.g.54"></span>  <a href="#date.time.formats.full.date" class="smpl">HTTP-date</a>    = <a href="#preferred.date.format" class="smpl">rfc1123-date</a> / <a href="#obsolete.date.formats" class="smpl">obs-date</a>
    16531614</pre><div id="preferred.date.format">
    16541615         <p id="rfc.section.6.1.p.8">                    Preferred format:</p>
    16551616      </div>
    1656       <div id="rfc.figure.u.44"></div><pre class="inline"><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><span id="rfc.iref.g.60"></span><span id="rfc.iref.g.61"></span><span id="rfc.iref.g.62"></span><span id="rfc.iref.g.63"></span><span id="rfc.iref.g.64"></span><span id="rfc.iref.g.65"></span>  <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#core.rules" class="smpl">SP</a> date1 <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
     1617      <div id="rfc.figure.u.45"></div><pre class="inline"><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><span id="rfc.iref.g.60"></span><span id="rfc.iref.g.61"></span><span id="rfc.iref.g.62"></span><span id="rfc.iref.g.63"></span><span id="rfc.iref.g.64"></span><span id="rfc.iref.g.65"></span><span id="rfc.iref.g.66"></span>  <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#core.rules" class="smpl">SP</a> date1 <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
    16571618  ; fixed length subset of the format defined in
    16581619  ; <a href="http://tools.ietf.org/html/rfc1123#section-5.2.14">Section 5.2.14</a> of <a href="#RFC1123" id="rfc.xref.RFC1123.2"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>
    … …  
    16971658         <p id="rfc.section.6.1.p.11">                Obsolete formats:</p>
    16981659      </div>
    1699       <div id="rfc.figure.u.45"></div><pre class="inline"><span id="rfc.iref.g.66"></span>  <a href="#obsolete.date.formats" class="smpl">obs-date</a>     = <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> / <a href="#obsolete.date.formats" class="smpl">asctime-date</a>
    1700 </pre><div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.67"></span>  <a href="#obsolete.date.formats" class="smpl">rfc850-date</a>  = <a href="#obsolete.date.formats" class="smpl">day-name-l</a> "," <a href="#core.rules" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date2</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
     1660      <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.67"></span>  <a href="#obsolete.date.formats" class="smpl">obs-date</a>     = <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> / <a href="#obsolete.date.formats" class="smpl">asctime-date</a>
     1661</pre><div id="rfc.figure.u.47"></div><pre class="inline"><span id="rfc.iref.g.68"></span>  <a href="#obsolete.date.formats" class="smpl">rfc850-date</a>  = <a href="#obsolete.date.formats" class="smpl">day-name-l</a> "," <a href="#core.rules" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date2</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
    17011662  <a href="#obsolete.date.formats" class="smpl">date2</a>        = <a href="#preferred.date.format" class="smpl">day</a> "-" <a href="#preferred.date.format" class="smpl">month</a> "-" 2<a href="#core.rules" class="smpl">DIGIT</a>
    17021663                 ; day-month-year (e.g., 02-Jun-82)
    … …  
    17091670         / %x53.61.74.75.72.64.61.79 ; "Saturday", case-sensitive
    17101671         / %x53.75.6E.64.61.79 ; "Sunday", case-sensitive
    1711 </pre><div id="rfc.figure.u.47"></div><pre class="inline"><span id="rfc.iref.g.68"></span>  <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> <a href="#core.rules" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date3</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">year</a>
     1672</pre><div id="rfc.figure.u.48"></div><pre class="inline"><span id="rfc.iref.g.69"></span>  <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> <a href="#core.rules" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date3</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">year</a>
    17121673  <a href="#obsolete.date.formats" class="smpl">date3</a>        = <a href="#preferred.date.format" class="smpl">month</a> <a href="#core.rules" class="smpl">SP</a> ( 2<a href="#core.rules" class="smpl">DIGIT</a> / ( <a href="#core.rules" class="smpl">SP</a> 1<a href="#core.rules" class="smpl">DIGIT</a> ))
    17131674                 ; month day (e.g., Jun  2)
    … …  
    17271688         transfer-coding is a property of the message rather than a property of the representation that is being transferred.
    17281689      </p>
    1729       <div id="rfc.figure.u.48"></div><pre class="inline"><span id="rfc.iref.g.69"></span><span id="rfc.iref.g.70"></span>  <a href="#transfer.codings" class="smpl">transfer-coding</a>         = "chunked" ; <a href="#chunked.encoding" title="Chunked Transfer Coding">Section&nbsp;6.2.1</a>
     1690      <div id="rfc.figure.u.49"></div><pre class="inline"><span id="rfc.iref.g.70"></span><span id="rfc.iref.g.71"></span>  <a href="#transfer.codings" class="smpl">transfer-coding</a>         = "chunked" ; <a href="#chunked.encoding" title="Chunked Transfer Coding">Section&nbsp;6.2.1</a>
    17301691                          / "compress" ; <a href="#compress.coding" title="Compress Coding">Section&nbsp;6.2.2.1</a>
    17311692                          / "deflate" ; <a href="#deflate.coding" title="Deflate Coding">Section&nbsp;6.2.2.2</a>
    … …  
    17361697         <p id="rfc.section.6.2.p.3">      Parameters are in the form of attribute/value pairs.</p>
    17371698      </div>
    1738       <div id="rfc.figure.u.49"></div><pre class="inline"><span id="rfc.iref.g.71"></span><span id="rfc.iref.g.72"></span><span id="rfc.iref.g.73"></span><span id="rfc.iref.g.74"></span><span id="rfc.iref.g.75"></span>  <a href="#rule.parameter" class="smpl">transfer-parameter</a>      = <a href="#rule.parameter" class="smpl">attribute</a> <a href="#rule.whitespace" class="smpl">BWS</a> "=" <a href="#rule.whitespace" class="smpl">BWS</a> <a href="#rule.parameter" class="smpl">value</a>
     1699      <div id="rfc.figure.u.50"></div><pre class="inline"><span id="rfc.iref.g.72"></span><span id="rfc.iref.g.73"></span><span id="rfc.iref.g.74"></span><span id="rfc.iref.g.75"></span><span id="rfc.iref.g.76"></span>  <a href="#rule.parameter" class="smpl">transfer-parameter</a>      = <a href="#rule.parameter" class="smpl">attribute</a> <a href="#rule.whitespace" class="smpl">BWS</a> "=" <a href="#rule.whitespace" class="smpl">BWS</a> <a href="#rule.parameter" class="smpl">value</a>
    17391700  <a href="#rule.parameter" class="smpl">attribute</a>               = <a href="#rule.token.separators" class="smpl">token</a>
    17401701  <a href="#rule.parameter" class="smpl">value</a>                   = <a href="#rule.token.separators" class="smpl">word</a>
    1741 </pre><p id="rfc.section.6.2.p.5">All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in the TE header field (<a href="#header.te" id="rfc.xref.header.te.1" title="TE">Section&nbsp;9.5</a>) and in the Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.3" title="Transfer-Encoding">Section&nbsp;9.7</a>).
     1702</pre><p id="rfc.section.6.2.p.5">All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in the TE header field (<a href="#header.te" id="rfc.xref.header.te.1" title="TE">Section&nbsp;9.5</a>) and in the Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section&nbsp;9.7</a>).
    17421703      </p>
    17431704      <p id="rfc.section.6.2.p.6">Transfer-codings are analogous to the Content-Transfer-Encoding values of MIME, which were designed to enable safe transport
    … …  
    17541715         for the recipient to verify that it has received the full message.
    17551716      </p>
    1756       <div id="rfc.figure.u.50"></div><pre class="inline"><span id="rfc.iref.g.76"></span><span id="rfc.iref.g.77"></span><span id="rfc.iref.g.78"></span><span id="rfc.iref.g.79"></span><span id="rfc.iref.g.80"></span><span id="rfc.iref.g.81"></span><span id="rfc.iref.g.82"></span><span id="rfc.iref.g.83"></span><span id="rfc.iref.g.84"></span><span id="rfc.iref.g.85"></span><span id="rfc.iref.g.86"></span>  <a href="#chunked.encoding" class="smpl">Chunked-Body</a>   = *<a href="#chunked.encoding" class="smpl">chunk</a>
     1717      <div id="rfc.figure.u.51"></div><pre class="inline"><span id="rfc.iref.g.77"></span><span id="rfc.iref.g.78"></span><span id="rfc.iref.g.79"></span><span id="rfc.iref.g.80"></span><span id="rfc.iref.g.81"></span><span id="rfc.iref.g.82"></span><span id="rfc.iref.g.83"></span><span id="rfc.iref.g.84"></span><span id="rfc.iref.g.85"></span><span id="rfc.iref.g.86"></span><span id="rfc.iref.g.87"></span>  <a href="#chunked.encoding" class="smpl">Chunked-Body</a>   = *<a href="#chunked.encoding" class="smpl">chunk</a>
    17571718                   <a href="#chunked.encoding" class="smpl">last-chunk</a>
    17581719                   <a href="#chunked.encoding" class="smpl">trailer-part</a>
    … …  
    17781739      </p>
    17791740      <p id="rfc.section.6.2.1.p.4">The trailer allows the sender to include additional HTTP header fields at the end of the message. The Trailer header field
    1780          can be used to indicate which header fields are included in a trailer (see <a href="#header.trailer" id="rfc.xref.header.trailer.2" title="Trailer">Section&nbsp;9.6</a>).
     1741         can be used to indicate which header fields are included in a trailer (see <a href="#header.trailer" id="rfc.xref.header.trailer.1" title="Trailer">Section&nbsp;9.6</a>).
    17811742      </p>
    17821743      <p id="rfc.section.6.2.1.p.5">A server using chunked transfer-coding in a response <em class="bcp14">MUST NOT</em> use the trailer for any header fields unless at least one of the following is true:
    … …  
    17971758      </p>
    17981759      <p id="rfc.section.6.2.1.p.7">A process for decoding the "chunked" transfer-coding can be represented in pseudo-code as:</p>
    1799       <div id="rfc.figure.u.51"></div><pre class="text">  length := 0
     1760      <div id="rfc.figure.u.52"></div><pre class="text">  length := 0
    18001761  read chunk-size, chunk-ext (if any) and CRLF
    18011762  while (chunk-size &gt; 0) {
    … …  
    18441805         </p>
    18451806      </div>
    1846       <div id="rfc.iref.g.87"></div>
     1807      <div id="rfc.iref.g.88"></div>
    18471808      <div id="rfc.iref.c.11"></div>
    18481809      <h4 id="rfc.section.6.2.2.3"><a href="#rfc.section.6.2.2.3">6.2.2.3</a>&nbsp;<a id="gzip.coding" href="#gzip.coding">Gzip Coding</a></h4>
    … …  
    18691830         By convention, the products are listed in order of their significance for identifying the application.
    18701831      </p>
    1871       <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.88"></span><span id="rfc.iref.g.89"></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>]
     1832      <div id="rfc.figure.u.53"></div><pre class="inline"><span id="rfc.iref.g.89"></span><span id="rfc.iref.g.90"></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>]
    18721833  <a href="#product.tokens" class="smpl">product-version</a> = <a href="#rule.token.separators" class="smpl">token</a>
    18731834</pre><p id="rfc.section.6.3.p.3">Examples:</p>
    1874       <div id="rfc.figure.u.53"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     1835      <div id="rfc.figure.u.54"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    18751836  Server: Apache/0.8.4
    18761837</pre><p id="rfc.section.6.3.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 octet <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).
    … …  
    18811842         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.
    18821843      </p>
    1883       <div id="rfc.figure.u.54"></div><pre class="inline"><span id="rfc.iref.g.90"></span>  <a href="#quality.values" class="smpl">qvalue</a>         = ( "0" [ "." 0*3<a href="#core.rules" class="smpl">DIGIT</a> ] )
     1844      <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.91"></span>  <a href="#quality.values" class="smpl">qvalue</a>         = ( "0" [ "." 0*3<a href="#core.rules" class="smpl">DIGIT</a> ] )
    18841845                 / ( "1" [ "." 0*3("0") ] )
    18851846</pre><div class="note" id="rfc.section.6.4.p.3">
    … …  
    19191880      </p>
    19201881      <p id="rfc.section.7.1.2.p.2">Persistent connections provide a mechanism by which a client and a server can signal the close of a TCP connection. This signaling
    1921          takes place using the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.5" title="Connection">Section&nbsp;9.1</a>). Once a close has been signaled, the client <em class="bcp14">MUST NOT</em> send any more requests on that connection.
     1882         takes place using the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.4" title="Connection">Section&nbsp;9.1</a>). Once a close has been signaled, the client <em class="bcp14">MUST NOT</em> send any more requests on that connection.
    19221883      </p>
    19231884      <h4 id="rfc.section.7.1.2.1"><a href="#rfc.section.7.1.2.1">7.1.2.1</a>&nbsp;<a id="persistent.negotiation" href="#persistent.negotiation">Negotiation</a></h4>
    … …  
    19451906      </p>
    19461907      <h3 id="rfc.section.7.1.3"><a href="#rfc.section.7.1.3">7.1.3</a>&nbsp;<a id="persistent.proxy" href="#persistent.proxy">Proxy Servers</a></h3>
    1947       <p id="rfc.section.7.1.3.p.1">It is especially important that proxies correctly implement the properties of the Connection header field as specified in <a href="#header.connection" id="rfc.xref.header.connection.6" title="Connection">Section&nbsp;9.1</a>.
     1908      <p id="rfc.section.7.1.3.p.1">It is especially important that proxies correctly implement the properties of the Connection header field as specified in <a href="#header.connection" id="rfc.xref.header.connection.5" title="Connection">Section&nbsp;9.1</a>.
    19481909      </p>
    19491910      <p id="rfc.section.7.1.3.p.2">The proxy server <em class="bcp14">MUST</em> signal persistent connections separately with its clients and the origin servers (or other proxy servers) that it connects
    … …  
    19741935      </ul>
    19751936      <p id="rfc.section.7.1.3.1.p.3">All other header fields defined by HTTP/1.1 are end-to-end header fields.</p>
    1976       <p id="rfc.section.7.1.3.1.p.4">Other hop-by-hop header fields <em class="bcp14">MUST</em> be listed in a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.7" title="Connection">Section&nbsp;9.1</a>).
     1937      <p id="rfc.section.7.1.3.1.p.4">Other hop-by-hop header fields <em class="bcp14">MUST</em> be listed in a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.6" title="Connection">Section&nbsp;9.1</a>).
    19771938      </p>
    19781939      <h4 id="rfc.section.7.1.3.2"><a href="#rfc.section.7.1.3.2">7.1.3.2</a>&nbsp;<a id="non-modifiable.header-fields" href="#non-modifiable.header-fields">Non-modifiable Header Fields</a></h4>
    … …  
    21522113      </p>
    21532114      <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a>&nbsp;<a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1>
    2154       <p id="rfc.section.9.p.1">This section defines the syntax and semantics of HTTP header fields related to message framing and transport protocols.</p>
     2115      <p id="rfc.section.9.p.1">This section defines the syntax and semantics of HTTP header fields related to message origination, framing, and routing.</p>
     2116      <div id="rfc.table.u.1">
     2117         <table class="tt full left" cellpadding="3" cellspacing="0">
     2118            <thead>
     2119               <tr>
     2120                  <th>Header Field Name</th>
     2121                  <th>Defined in...</th>
     2122               </tr>
     2123            </thead>
     2124            <tbody>
     2125               <tr>
     2126                  <td class="left">Connection</td>
     2127                  <td class="left"><a href="#header.connection" id="rfc.xref.header.connection.7" title="Connection">Section&nbsp;9.1</a></td>
     2128               </tr>
     2129               <tr>
     2130                  <td class="left">Content-Length</td>
     2131                  <td class="left"><a href="#header.content-length" id="rfc.xref.header.content-length.2" title="Content-Length">Section&nbsp;9.2</a></td>
     2132               </tr>
     2133               <tr>
     2134                  <td class="left">Date</td>
     2135                  <td class="left"><a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section&nbsp;9.3</a></td>
     2136               </tr>
     2137               <tr>
     2138                  <td class="left">Host</td>
     2139                  <td class="left"><a href="#header.host" id="rfc.xref.header.host.2" title="Host">Section&nbsp;9.4</a></td>
     2140               </tr>
     2141               <tr>
     2142                  <td class="left">TE</td>
     2143                  <td class="left"><a href="#header.te" id="rfc.xref.header.te.4" title="TE">Section&nbsp;9.5</a></td>
     2144               </tr>
     2145               <tr>
     2146                  <td class="left">Trailer</td>
     2147                  <td class="left"><a href="#header.trailer" id="rfc.xref.header.trailer.2" title="Trailer">Section&nbsp;9.6</a></td>
     2148               </tr>
     2149               <tr>
     2150                  <td class="left">Transfer-Encoding</td>
     2151                  <td class="left"><a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.3" title="Transfer-Encoding">Section&nbsp;9.7</a></td>
     2152               </tr>
     2153               <tr>
     2154                  <td class="left">Upgrade</td>
     2155                  <td class="left"><a href="#header.upgrade" id="rfc.xref.header.upgrade.1" title="Upgrade">Section&nbsp;9.8</a></td>
     2156               </tr>
     2157               <tr>
     2158                  <td class="left">Via</td>
     2159                  <td class="left"><a href="#header.via" id="rfc.xref.header.via.2" title="Via">Section&nbsp;9.9</a></td>
     2160               </tr>
     2161            </tbody>
     2162         </table>
     2163      </div>
    21552164      <div id="rfc.iref.c.12"></div>
    21562165      <div id="rfc.iref.h.6"></div>
    … …  
    21642173      </p>
    21652174      <p id="rfc.section.9.1.p.2">The Connection header field's value has the following grammar:</p>
    2166       <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.91"></span><span id="rfc.iref.g.92"></span>  <a href="#header.connection" class="smpl">Connection</a>       = 1#<a href="#header.connection" class="smpl">connection-token</a>
     2175      <div id="rfc.figure.u.56"></div><pre class="inline"><span id="rfc.iref.g.92"></span><span id="rfc.iref.g.93"></span>  <a href="#header.connection" class="smpl">Connection</a>       = 1#<a href="#header.connection" class="smpl">connection-token</a>
    21672176  <a href="#header.connection" class="smpl">connection-token</a> = <a href="#rule.token.separators" class="smpl">token</a>
    21682177</pre><p id="rfc.section.9.1.p.4">A proxy or gateway <em class="bcp14">MUST</em> parse a received Connection header field before a message is forwarded and, for each connection-token in this field, remove
    … …  
    21872196         of the response. For example,
    21882197      </p>
    2189       <div id="rfc.figure.u.56"></div><pre class="text">  Connection: close
     2198      <div id="rfc.figure.u.57"></div><pre class="text">  Connection: close
    21902199</pre><p id="rfc.section.9.1.p.10">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.
    21912200      </p>
    … …  
    22032212         body (not including any potential transfer-coding) that would have been sent in a 200 (OK) response.
    22042213      </p>
    2205       <div id="rfc.figure.u.57"></div><pre class="inline"><span id="rfc.iref.g.93"></span>  <a href="#header.content-length" class="smpl">Content-Length</a> = 1*<a href="#core.rules" class="smpl">DIGIT</a>
     2214      <div id="rfc.figure.u.58"></div><pre class="inline"><span id="rfc.iref.g.94"></span>  <a href="#header.content-length" class="smpl">Content-Length</a> = 1*<a href="#core.rules" class="smpl">DIGIT</a>
    22062215</pre><p id="rfc.section.9.2.p.3">An example is</p>
    2207       <div id="rfc.figure.u.58"></div><pre class="text">  Content-Length: 3495
     2216      <div id="rfc.figure.u.59"></div><pre class="text">  Content-Length: 3495
    22082217</pre><p id="rfc.section.9.2.p.5">Implementations <em class="bcp14">SHOULD</em> use this field to indicate the message-body length when no transfer-coding is being applied and the payload's body length
    22092218         can be determined prior to being transferred. <a href="#message.body" title="Message Body">Section&nbsp;3.3</a> describes how recipients determine the length of a message-body.
    … …  
    22192228         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.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as described in <a href="#date.time.formats.full.date" title="Date/Time Formats: Full Date">Section&nbsp;6.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.
    22202229      </p>
    2221       <div id="rfc.figure.u.59"></div><pre class="inline"><span id="rfc.iref.g.94"></span>  <a href="#header.date" class="smpl">Date</a> = <a href="#date.time.formats.full.date" class="smpl">HTTP-date</a>
     2230      <div id="rfc.figure.u.60"></div><pre class="inline"><span id="rfc.iref.g.95"></span>  <a href="#header.date" class="smpl">Date</a> = <a href="#date.time.formats.full.date" class="smpl">HTTP-date</a>
    22222231</pre><p id="rfc.section.9.3.p.3">An example is</p>
    2223       <div id="rfc.figure.u.60"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
     2232      <div id="rfc.figure.u.61"></div><pre class="text">  Date: Tue, 15 Nov 1994 08:12:31 GMT
    22242233</pre><p id="rfc.section.9.3.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:
    22252234      </p>
    … …  
    22552264         Host field-value is critical information for handling a request, it <em class="bcp14">SHOULD</em> be sent as the first header field following the Request-Line.
    22562265      </p>
    2257       <div id="rfc.figure.u.61"></div><pre class="inline"><span id="rfc.iref.g.95"></span>  <a href="#header.host" class="smpl">Host</a> = <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;2.7.1</a>
     2266      <div id="rfc.figure.u.62"></div><pre class="inline"><span id="rfc.iref.g.96"></span>  <a href="#header.host" class="smpl">Host</a> = <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;2.7.1</a>
    22582267</pre><p id="rfc.section.9.4.p.3">A client <em class="bcp14">MUST</em> send a Host header field in all HTTP/1.1 request messages. If the target resource's URI includes an authority component, then
    22592268         the Host field-value <em class="bcp14">MUST</em> be identical to that authority component after excluding any userinfo (<a href="#http.uri" title="http URI scheme">Section&nbsp;2.7.1</a>). If the authority component is missing or undefined for the target resource's URI, then the Host header field <em class="bcp14">MUST</em> be sent with an empty field-value.
    22602269      </p>
    22612270      <p id="rfc.section.9.4.p.4">For example, a GET request to the origin server for &lt;http://www.example.org/pub/WWW/&gt; would begin with:</p>
    2262       <div id="rfc.figure.u.62"></div><pre class="text2">GET /pub/WWW/ HTTP/1.1
     2271      <div id="rfc.figure.u.63"></div><pre class="text2">GET /pub/WWW/ HTTP/1.1
    22632272Host: www.example.org
    22642273</pre><p id="rfc.section.9.4.p.6">The Host header field <em class="bcp14">MUST</em> be sent in an HTTP/1.1 request even if the request-target is in the form of an absolute-URI, since this allows the Host information
    … …  
    22872296         accept parameters (as described in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;6.2</a>).
    22882297      </p>
    2289       <div id="rfc.figure.u.63"></div><pre class="inline"><span id="rfc.iref.g.96"></span><span id="rfc.iref.g.97"></span><span id="rfc.iref.g.98"></span><span id="rfc.iref.g.99"></span>  <a href="#header.te" class="smpl">TE</a>        = #<a href="#header.te" class="smpl">t-codings</a>
     2298      <div id="rfc.figure.u.64"></div><pre class="inline"><span id="rfc.iref.g.97"></span><span id="rfc.iref.g.98"></span><span id="rfc.iref.g.99"></span><span id="rfc.iref.g.100"></span>  <a href="#header.te" class="smpl">TE</a>        = #<a href="#header.te" class="smpl">t-codings</a>
    22902299  <a href="#header.te" class="smpl">t-codings</a> = "trailers" / ( <a href="#transfer.codings" class="smpl">transfer-extension</a> [ <a href="#header.te" class="smpl">te-params</a> ] )
    22912300  <a href="#header.te" class="smpl">te-params</a> = <a href="#rule.whitespace" class="smpl">OWS</a> ";" <a href="#rule.whitespace" class="smpl">OWS</a> "q=" <a href="#quality.values" class="smpl">qvalue</a> *( <a href="#header.te" class="smpl">te-ext</a> )
    … …  
    22952304      </p>
    22962305      <p id="rfc.section.9.5.p.5">Examples of its use are:</p>
    2297       <div id="rfc.figure.u.64"></div><pre class="text">  TE: deflate
     2306      <div id="rfc.figure.u.65"></div><pre class="text">  TE: deflate
    22982307  TE:
    22992308  TE: trailers, deflate;q=0.5
    … …  
    23322341         chunked transfer-coding.
    23332342      </p>
    2334       <div id="rfc.figure.u.65"></div><pre class="inline"><span id="rfc.iref.g.100"></span>  <a href="#header.trailer" class="smpl">Trailer</a> = 1#<a href="#header.fields" class="smpl">field-name</a>
     2343      <div id="rfc.figure.u.66"></div><pre class="inline"><span id="rfc.iref.g.101"></span>  <a href="#header.trailer" class="smpl">Trailer</a> = 1#<a href="#header.fields" class="smpl">field-name</a>
    23352344</pre><p id="rfc.section.9.6.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
    23362345         to know which header fields to expect in the trailer.
    … …  
    23522361         are not.
    23532362      </p>
    2354       <div id="rfc.figure.u.66"></div><pre class="inline"><span id="rfc.iref.g.101"></span>  <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a> = 1#<a href="#transfer.codings" class="smpl">transfer-coding</a>
     2363      <div id="rfc.figure.u.67"></div><pre class="inline"><span id="rfc.iref.g.102"></span>  <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a> = 1#<a href="#transfer.codings" class="smpl">transfer-coding</a>
    23552364</pre><p id="rfc.section.9.7.p.3">Transfer-codings are defined in <a href="#transfer.codings" title="Transfer Codings">Section&nbsp;6.2</a>. An example is:
    23562365      </p>
    2357       <div id="rfc.figure.u.67"></div><pre class="text">  Transfer-Encoding: chunked
     2366      <div id="rfc.figure.u.68"></div><pre class="text">  Transfer-Encoding: chunked
    23582367</pre><p id="rfc.section.9.7.p.5">If multiple encodings have been applied to a representation, 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 header fields not defined by this specification.
    23592368      </p>
    … …  
    23652374         server chooses to switch protocols. Servers can use it to indicate what protocols they are willing to switch to.
    23662375      </p>
    2367       <div id="rfc.figure.u.68"></div><pre class="inline"><span id="rfc.iref.g.102"></span>  <a href="#header.upgrade" class="smpl">Upgrade</a> = 1#<a href="#product.tokens" class="smpl">product</a>
     2376      <div id="rfc.figure.u.69"></div><pre class="inline"><span id="rfc.iref.g.103"></span>  <a href="#header.upgrade" class="smpl">Upgrade</a> = 1#<a href="#product.tokens" class="smpl">product</a>
    23682377</pre><p id="rfc.section.9.8.p.3">For example,</p>
    2369       <div id="rfc.figure.u.69"></div><pre class="text">  Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
     2378      <div id="rfc.figure.u.70"></div><pre class="text">  Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11
    23702379</pre><p id="rfc.section.9.8.p.5">The Upgrade header field is intended to provide a simple mechanism for transition from HTTP/1.1 to some other, incompatible
    23712380         protocol. It does so by allowing the client to advertise its desire to use another protocol, such as a later version of HTTP
    … …  
    24222431         of all senders along the request/response chain.
    24232432      </p>
    2424       <div id="rfc.figure.u.70"></div><pre class="inline"><span id="rfc.iref.g.103"></span><span id="rfc.iref.g.104"></span><span id="rfc.iref.g.105"></span><span id="rfc.iref.g.106"></span><span id="rfc.iref.g.107"></span><span id="rfc.iref.g.108"></span>  <a href="#header.via" class="smpl">Via</a>               = 1#( <a href="#header.via" class="smpl">received-protocol</a> <a href="#rule.whitespace" class="smpl">RWS</a> <a href="#header.via" class="smpl">received-by</a>
     2433      <div id="rfc.figure.u.71"></div><pre class="inline"><span id="rfc.iref.g.104"></span><span id="rfc.iref.g.105"></span><span id="rfc.iref.g.106"></span><span id="rfc.iref.g.107"></span><span id="rfc.iref.g.108"></span><span id="rfc.iref.g.109"></span>  <a href="#header.via" class="smpl">Via</a>               = 1#( <a href="#header.via" class="smpl">received-protocol</a> <a href="#rule.whitespace" class="smpl">RWS</a> <a href="#header.via" class="smpl">received-by</a>
    24252434                          [ <a href="#rule.whitespace" class="smpl">RWS</a> <a href="#rule.comment" class="smpl">comment</a> ] )
    24262435  <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>
    … …  
    24462455         server at www.example.com. The request received by www.example.com would then have the following Via header field:
    24472456      </p>
    2448       <div id="rfc.figure.u.71"></div><pre class="text">  Via: 1.0 fred, 1.1 p.example.net (Apache/1.1)
     2457      <div id="rfc.figure.u.72"></div><pre class="text">  Via: 1.0 fred, 1.1 p.example.net (Apache/1.1)
    24492458</pre><p id="rfc.section.9.9.p.9">A proxy or gateway used as a portal through a network firewall <em class="bcp14">SHOULD NOT</em> forward the names and ports of hosts within the firewall region unless it is explicitly enabled to do so. If not enabled,
    24502459         the received-by host of any host behind the firewall <em class="bcp14">SHOULD</em> be replaced by an appropriate pseudonym for that host.
    … …  
    24532462         For example,
    24542463      </p>
    2455       <div id="rfc.figure.u.72"></div><pre class="text">  Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy
     2464      <div id="rfc.figure.u.73"></div><pre class="text">  Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy
    24562465</pre><p id="rfc.section.9.9.p.12">could be collapsed to</p>
    2457       <div id="rfc.figure.u.73"></div><pre class="text">  Via: 1.0 ricky, 1.1 mertz, 1.0 lucy
     2466      <div id="rfc.figure.u.74"></div><pre class="text">  Via: 1.0 ricky, 1.1 mertz, 1.0 lucy
    24582467</pre><p id="rfc.section.9.9.p.14">Senders <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
    24592468         by pseudonyms. Senders <em class="bcp14">MUST NOT</em> combine entries which have different received-protocol values.
    … …  
    24862495                  <td class="left">http</td>
    24872496                  <td class="left">standard</td>
    2488                   <td class="left"> <a href="#header.content-length" id="rfc.xref.header.content-length.2" title="Content-Length">Section&nbsp;9.2</a>
     2497                  <td class="left"> <a href="#header.content-length" id="rfc.xref.header.content-length.3" title="Content-Length">Section&nbsp;9.2</a>
    24892498                  </td>
    24902499               </tr>
    … …  
    25002509                  <td class="left">http</td>
    25012510                  <td class="left">standard</td>
    2502                   <td class="left"> <a href="#header.host" id="rfc.xref.header.host.2" title="Host">Section&nbsp;9.4</a>
     2511                  <td class="left"> <a href="#header.host" id="rfc.xref.header.host.3" title="Host">Section&nbsp;9.4</a>
    25032512                  </td>
    25042513               </tr>
    … …  
    25072516                  <td class="left">http</td>
    25082517                  <td class="left">standard</td>
    2509                   <td class="left"> <a href="#header.te" id="rfc.xref.header.te.4" title="TE">Section&nbsp;9.5</a>
     2518                  <td class="left"> <a href="#header.te" id="rfc.xref.header.te.5" title="TE">Section&nbsp;9.5</a>
    25102519                  </td>
    25112520               </tr>
    … …  
    30653074      <p id="rfc.section.A.1.p.1">This section summarizes major differences between versions HTTP/1.0 and HTTP/1.1.</p>
    30663075      <h3 id="rfc.section.A.1.1"><a href="#rfc.section.A.1.1">A.1.1</a>&nbsp;<a id="changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses">Multi-homed Web Servers</a></h3>
    3067       <p id="rfc.section.A.1.1.p.1">The requirements that clients and servers support the Host header field (<a href="#header.host" id="rfc.xref.header.host.3" title="Host">Section&nbsp;9.4</a>), report an error if it is missing from an HTTP/1.1 request, and accept absolute URIs (<a href="#request-target" title="request-target">Section&nbsp;4.1.2</a>) are among the most important changes defined by HTTP/1.1.
     3076      <p id="rfc.section.A.1.1.p.1">The requirements that clients and servers support the Host header field (<a href="#header.host" id="rfc.xref.header.host.4" title="Host">Section&nbsp;9.4</a>), report an error if it is missing from an HTTP/1.1 request, and accept absolute URIs (<a href="#request-target" title="request-target">Section&nbsp;4.1.2</a>) are among the most important changes defined by HTTP/1.1.
    30683077      </p>
    30693078      <p id="rfc.section.A.1.1.p.2">Older HTTP/1.0 clients assumed a one-to-one relationship of IP addresses and servers; there was no other established mechanism
    … …  
    31253134      </p>
    31263135      <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a>&nbsp;<a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1>
    3127       <div id="rfc.figure.u.74"></div> <pre class="inline"><a href="#rule.whitespace" class="smpl">BWS</a> = OWS
     3136      <div id="rfc.figure.u.75"></div> <pre class="inline"><a href="#rule.whitespace" class="smpl">BWS</a> = OWS
    31283137
    31293138<a href="#chunked.encoding" class="smpl">Chunked-Body</a> = *chunk last-chunk trailer-part CRLF
    … …  
    32913300
    32923301<a href="#preferred.date.format" class="smpl">year</a> = 4DIGIT
    3293 </pre> <div id="rfc.figure.u.75"></div>
     3302</pre> <div id="rfc.figure.u.76"></div>
    32943303      <p>ABNF diagnostics:</p><pre class="inline">; Chunked-Body defined but not used
    32953304; Connection defined but not used
    … …  
    36963705                  <li>compress (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.c.8">6.2.2.1</a></li>
    36973706                  <li>connection&nbsp;&nbsp;<a href="#rfc.iref.c.2"><b>2.1</b></a></li>
    3698                   <li>Connection header field&nbsp;&nbsp;<a href="#rfc.xref.header.connection.1">2.4</a>, <a href="#rfc.xref.header.connection.2">2.6</a>, <a href="#rfc.xref.header.connection.3">3.2</a>, <a href="#rfc.xref.header.connection.4">3.5</a>, <a href="#rfc.xref.header.connection.5">7.1.2</a>, <a href="#rfc.xref.header.connection.6">7.1.3</a>, <a href="#rfc.xref.header.connection.7">7.1.3.1</a>, <a href="#rfc.iref.c.12"><b>9.1</b></a>, <a href="#rfc.xref.header.connection.8">9.5</a>, <a href="#rfc.xref.header.connection.9">9.8</a>, <a href="#rfc.xref.header.connection.10">10.1</a>, <a href="#rfc.xref.header.connection.11">10.1</a>, <a href="#rfc.xref.header.connection.12">A.1.2</a>, <a href="#rfc.xref.header.connection.13">A.2</a></li>
    3699                   <li>Content-Length header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-length.1">3.3</a>, <a href="#rfc.iref.c.13"><b>9.2</b></a>, <a href="#rfc.xref.header.content-length.2">10.1</a></li>
     3707                  <li>Connection header field&nbsp;&nbsp;<a href="#rfc.xref.header.connection.1">2.4</a>, <a href="#rfc.xref.header.connection.2">2.6</a>, <a href="#rfc.xref.header.connection.3">3.2</a>, <a href="#rfc.xref.header.connection.4">7.1.2</a>, <a href="#rfc.xref.header.connection.5">7.1.3</a>, <a href="#rfc.xref.header.connection.6">7.1.3.1</a>, <a href="#rfc.xref.header.connection.7">9</a>, <a href="#rfc.iref.c.12"><b>9.1</b></a>, <a href="#rfc.xref.header.connection.8">9.5</a>, <a href="#rfc.xref.header.connection.9">9.8</a>, <a href="#rfc.xref.header.connection.10">10.1</a>, <a href="#rfc.xref.header.connection.11">10.1</a>, <a href="#rfc.xref.header.connection.12">A.1.2</a>, <a href="#rfc.xref.header.connection.13">A.2</a></li>
     3708                  <li>Content-Length header field&nbsp;&nbsp;<a href="#rfc.xref.header.content-length.1">3.3</a>, <a href="#rfc.xref.header.content-length.2">9</a>, <a href="#rfc.iref.c.13"><b>9.2</b></a>, <a href="#rfc.xref.header.content-length.3">10.1</a></li>
    37003709               </ul>
    37013710            </li>
    37023711            <li><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul>
    3703                   <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.2</a>, <a href="#rfc.xref.header.date.2">3.5</a>, <a href="#rfc.iref.d.3"><b>9.3</b></a>, <a href="#rfc.xref.header.date.3">10.1</a></li>
     3712                  <li>Date header field&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.2</a>, <a href="#rfc.xref.header.date.2">9</a>, <a href="#rfc.iref.d.3"><b>9.3</b></a>, <a href="#rfc.xref.header.date.3">10.1</a></li>
    37043713                  <li>deflate (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.d.2">6.2.2.2</a></li>
    37053714                  <li>downstream&nbsp;&nbsp;<a href="#rfc.iref.d.1"><b>2.4</b></a></li>
    … …  
    37163725                        <li><tt>absolute-URI</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.20"><b>2.7</b></a></li>
    37173726                        <li>ALPHA&nbsp;&nbsp;<a href="#rfc.iref.g.1"><b>1.2</b></a></li>
    3718                         <li><tt>asctime-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.68"><b>6.1</b></a></li>
    3719                         <li><tt>attribute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.72"><b>6.2</b></a></li>
     3727                        <li><tt>asctime-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.69"><b>6.1</b></a></li>
     3728                        <li><tt>attribute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.73"><b>6.2</b></a></li>
    37203729                        <li><tt>authority</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.21"><b>2.7</b></a></li>
    37213730                        <li><tt>BWS</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.15"><b>1.2.2</b></a></li>
    3722                         <li><tt>chunk</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.77"><b>6.2.1</b></a></li>
    3723                         <li><tt>chunk-data</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.83"><b>6.2.1</b></a></li>
    3724                         <li><tt>chunk-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.80"><b>6.2.1</b></a></li>
    3725                         <li><tt>chunk-ext-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.81"><b>6.2.1</b></a></li>
    3726                         <li><tt>chunk-ext-val</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.82"><b>6.2.1</b></a></li>
    3727                         <li><tt>chunk-size</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.78"><b>6.2.1</b></a></li>
    3728                         <li><tt>Chunked-Body</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.76"><b>6.2.1</b></a></li>
    3729                         <li><tt>comment</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.41"><b>3.2.3</b></a></li>
    3730                         <li><tt>Connection</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.91"><b>9.1</b></a></li>
    3731                         <li><tt>connection-token</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.92"><b>9.1</b></a></li>
    3732                         <li><tt>Content-Length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.93"><b>9.2</b></a></li>
     3731                        <li><tt>chunk</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.78"><b>6.2.1</b></a></li>
     3732                        <li><tt>chunk-data</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.84"><b>6.2.1</b></a></li>
     3733                        <li><tt>chunk-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.81"><b>6.2.1</b></a></li>
     3734                        <li><tt>chunk-ext-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.82"><b>6.2.1</b></a></li>
     3735                        <li><tt>chunk-ext-val</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.83"><b>6.2.1</b></a></li>
     3736                        <li><tt>chunk-size</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.79"><b>6.2.1</b></a></li>
     3737                        <li><tt>Chunked-Body</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.77"><b>6.2.1</b></a></li>
     3738                        <li><tt>comment</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.42"><b>3.2.3</b></a></li>
     3739                        <li><tt>Connection</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.92"><b>9.1</b></a></li>
     3740                        <li><tt>connection-token</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.93"><b>9.1</b></a></li>
     3741                        <li><tt>Content-Length</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.94"><b>9.2</b></a></li>
    37333742                        <li>CR&nbsp;&nbsp;<a href="#rfc.iref.g.2"><b>1.2</b></a></li>
    37343743                        <li>CRLF&nbsp;&nbsp;<a href="#rfc.iref.g.3"><b>1.2</b></a></li>
    3735                         <li><tt>ctext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.42"><b>3.2.3</b></a></li>
     3744                        <li><tt>ctext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.43"><b>3.2.3</b></a></li>
    37363745                        <li>CTL&nbsp;&nbsp;<a href="#rfc.iref.g.4"><b>1.2</b></a></li>
    3737                         <li><tt>Date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.94"><b>9.3</b></a></li>
    3738                         <li><tt>date1</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.55"><b>6.1</b></a></li>
    3739                         <li><tt>date2</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.74"><b>6.2</b></a></li>
    3740                         <li><tt>date3</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.75"><b>6.2</b></a></li>
    3741                         <li><tt>day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.62"><b>6.1</b></a></li>
    3742                         <li><tt>day-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.60"><b>6.1</b></a></li>
    3743                         <li><tt>day-name-l</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.61"><b>6.1</b></a></li>
     3746                        <li><tt>Date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.95"><b>9.3</b></a></li>
     3747                        <li><tt>date1</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.56"><b>6.1</b></a></li>
     3748                        <li><tt>date2</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.75"><b>6.2</b></a></li>
     3749                        <li><tt>date3</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.76"><b>6.2</b></a></li>
     3750                        <li><tt>day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.63"><b>6.1</b></a></li>
     3751                        <li><tt>day-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.61"><b>6.1</b></a></li>
     3752                        <li><tt>day-name-l</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.62"><b>6.1</b></a></li>
    37443753                        <li>DIGIT&nbsp;&nbsp;<a href="#rfc.iref.g.5"><b>1.2</b></a></li>
    37453754                        <li>DQUOTE&nbsp;&nbsp;<a href="#rfc.iref.g.6"><b>1.2</b></a></li>
    3746                         <li><tt>field-content</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.32"><b>3.2</b></a></li>
    3747                         <li><tt>field-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.30"><b>3.2</b></a></li>
    3748                         <li><tt>field-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.31"><b>3.2</b></a></li>
    3749                         <li><tt>GMT</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.65"><b>6.1</b></a></li>
    3750                         <li><tt>header-field</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.29"><b>3.2</b></a></li>
     3755                        <li><tt>field-content</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.33"><b>3.2</b></a></li>
     3756                        <li><tt>field-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.31"><b>3.2</b></a></li>
     3757                        <li><tt>field-value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.32"><b>3.2</b></a></li>
     3758                        <li><tt>GMT</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.66"><b>6.1</b></a></li>
     3759                        <li><tt>header-field</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.30"><b>3.2</b></a></li>
    37513760                        <li>HEXDIG&nbsp;&nbsp;<a href="#rfc.iref.g.7"><b>1.2</b></a></li>
    3752                         <li><tt>Host</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.95"><b>9.4</b></a></li>
    3753                         <li><tt>hour</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.57"><b>6.1</b></a></li>
     3761                        <li><tt>Host</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.96"><b>9.4</b></a></li>
     3762                        <li><tt>hour</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.58"><b>6.1</b></a></li>
    37543763                        <li>HTAB&nbsp;&nbsp;<a href="#rfc.iref.g.8"><b>1.2</b></a></li>
    3755                         <li><tt>HTTP-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.53"><b>6.1</b></a></li>
     3764                        <li><tt>HTTP-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.54"><b>6.1</b></a></li>
    37563765                        <li><tt>HTTP-message</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.28"><b>3</b></a></li>
    37573766                        <li><tt>HTTP-Prot-Name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.18"><b>2.6</b></a></li>
    … …  
    37593768                        <li><tt>HTTP-Version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.17"><b>2.6</b></a></li>
    37603769                        <li><tt>https-URI</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.27"><b>2.7.2</b></a></li>
    3761                         <li><tt>last-chunk</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.79"><b>6.2.1</b></a></li>
     3770                        <li><tt>last-chunk</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.80"><b>6.2.1</b></a></li>
    37623771                        <li>LF&nbsp;&nbsp;<a href="#rfc.iref.g.9"><b>1.2</b></a></li>
    3763                         <li><tt>message-body</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.44"><b>3.3</b></a></li>
    3764                         <li><tt>Method</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.47"><b>4.1.1</b></a></li>
    3765                         <li><tt>minute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.58"><b>6.1</b></a></li>
    3766                         <li><tt>month</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.63"><b>6.1</b></a></li>
    3767                         <li><tt>obs-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.66"><b>6.1</b></a></li>
    3768                         <li><tt>obs-text</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.39"><b>3.2.3</b></a></li>
     3772                        <li><tt>message-body</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.45"><b>3.3</b></a></li>
     3773                        <li><tt>Method</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.48"><b>4.1.1</b></a></li>
     3774                        <li><tt>minute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.59"><b>6.1</b></a></li>
     3775                        <li><tt>month</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.64"><b>6.1</b></a></li>
     3776                        <li><tt>obs-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.67"><b>6.1</b></a></li>
     3777                        <li><tt>obs-text</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.40"><b>3.2.3</b></a></li>
    37693778                        <li>OCTET&nbsp;&nbsp;<a href="#rfc.iref.g.10"><b>1.2</b></a></li>
    37703779                        <li><tt>OWS</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.13"><b>1.2.2</b></a></li>
    37713780                        <li><tt>path-absolute</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.22"><b>2.7</b></a></li>
    37723781                        <li><tt>port</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.23"><b>2.7</b></a></li>
    3773                         <li><tt>product</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.88"><b>6.3</b></a></li>
    3774                         <li><tt>product-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.89"><b>6.3</b></a></li>
    3775                         <li><tt>protocol-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.105"><b>9.9</b></a></li>
    3776                         <li><tt>protocol-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.106"><b>9.9</b></a></li>
    3777                         <li><tt>pseudonym</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.108"><b>9.9</b></a></li>
    3778                         <li><tt>qdtext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.38"><b>3.2.3</b></a></li>
    3779                         <li><tt>qdtext-nf</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.86"><b>6.2.1</b></a></li>
     3782                        <li><tt>product</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.89"><b>6.3</b></a></li>
     3783                        <li><tt>product-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.90"><b>6.3</b></a></li>
     3784                        <li><tt>protocol-name</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.106"><b>9.9</b></a></li>
     3785                        <li><tt>protocol-version</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.107"><b>9.9</b></a></li>
     3786                        <li><tt>pseudonym</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.109"><b>9.9</b></a></li>
     3787                        <li><tt>qdtext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.39"><b>3.2.3</b></a></li>
     3788                        <li><tt>qdtext-nf</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.87"><b>6.2.1</b></a></li>
    37803789                        <li><tt>query</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.24"><b>2.7</b></a></li>
    3781                         <li><tt>quoted-cpair</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.43"><b>3.2.3</b></a></li>
    3782                         <li><tt>quoted-pair</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.40"><b>3.2.3</b></a></li>
    3783                         <li><tt>quoted-str-nf</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.85"><b>6.2.1</b></a></li>
    3784                         <li><tt>quoted-string</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.37"><b>3.2.3</b></a></li>
    3785                         <li><tt>qvalue</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.90"><b>6.4</b></a></li>
    3786                         <li><tt>Reason-Phrase</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.52"><b>5.1.1</b></a></li>
    3787                         <li><tt>received-by</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.107"><b>9.9</b></a></li>
    3788                         <li><tt>received-protocol</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.104"><b>9.9</b></a></li>
    3789                         <li><tt>Request</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.45"><b>4</b></a></li>
    3790                         <li><tt>Request-Line</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.46"><b>4.1</b></a></li>
    3791                         <li><tt>request-target</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.48"><b>4.1.2</b></a></li>
    3792                         <li><tt>Response</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.49"><b>5</b></a></li>
    3793                         <li><tt>rfc1123-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.54"><b>6.1</b></a></li>
    3794                         <li><tt>rfc850-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.67"><b>6.1</b></a></li>
     3790                        <li><tt>quoted-cpair</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.44"><b>3.2.3</b></a></li>
     3791                        <li><tt>quoted-pair</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.41"><b>3.2.3</b></a></li>
     3792                        <li><tt>quoted-str-nf</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.86"><b>6.2.1</b></a></li>
     3793                        <li><tt>quoted-string</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.38"><b>3.2.3</b></a></li>
     3794                        <li><tt>qvalue</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.91"><b>6.4</b></a></li>
     3795                        <li><tt>Reason-Phrase</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.53"><b>5.1.1</b></a></li>
     3796                        <li><tt>received-by</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.108"><b>9.9</b></a></li>
     3797                        <li><tt>received-protocol</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.105"><b>9.9</b></a></li>
     3798                        <li><tt>Request</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.46"><b>4</b></a></li>
     3799                        <li><tt>Request-Line</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.47"><b>4.1</b></a></li>
     3800                        <li><tt>request-target</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.49"><b>4.1.2</b></a></li>
     3801                        <li><tt>Response</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.50"><b>5</b></a></li>
     3802                        <li><tt>rfc1123-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.55"><b>6.1</b></a></li>
     3803                        <li><tt>rfc850-date</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.68"><b>6.1</b></a></li>
    37953804                        <li><tt>RWS</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.14"><b>1.2.2</b></a></li>
    3796                         <li><tt>second</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.59"><b>6.1</b></a></li>
     3805                        <li><tt>second</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.60"><b>6.1</b></a></li>
    37973806                        <li>SP&nbsp;&nbsp;<a href="#rfc.iref.g.11"><b>1.2</b></a></li>
    3798                         <li><tt>special</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.36"><b>3.2.3</b></a></li>
    3799                         <li><tt>Status-Code</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.51"><b>5.1.1</b></a></li>
    3800                         <li><tt>Status-Line</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.50"><b>5.1</b></a></li>
    3801                         <li><tt>t-codings</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.97"><b>9.5</b></a></li>
    3802                         <li><tt>tchar</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.35"><b>3.2.3</b></a></li>
    3803                         <li><tt>TE</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.96"><b>9.5</b></a></li>
    3804                         <li><tt>te-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.99"><b>9.5</b></a></li>
    3805                         <li><tt>te-params</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.98"><b>9.5</b></a></li>
    3806                         <li><tt>time-of-day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.56"><b>6.1</b></a></li>
    3807                         <li><tt>token</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.34"><b>3.2.3</b></a></li>
    3808                         <li><tt>Trailer</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.100"><b>9.6</b></a></li>
    3809                         <li><tt>trailer-part</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.84"><b>6.2.1</b></a></li>
    3810                         <li><tt>transfer-coding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.69"><b>6.2</b></a></li>
    3811                         <li><tt>Transfer-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.101"><b>9.7</b></a></li>
    3812                         <li><tt>transfer-extension</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.70"><b>6.2</b></a></li>
    3813                         <li><tt>transfer-parameter</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.71"><b>6.2</b></a></li>
    3814                         <li><tt>Upgrade</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.102"><b>9.8</b></a></li>
     3807                        <li><tt>special</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.37"><b>3.2.3</b></a></li>
     3808                        <li><tt>start-line</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.29"><b>3.1</b></a></li>
     3809                        <li><tt>Status-Code</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.52"><b>5.1.1</b></a></li>
     3810                        <li><tt>Status-Line</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.51"><b>5.1</b></a></li>
     3811                        <li><tt>t-codings</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.98"><b>9.5</b></a></li>
     3812                        <li><tt>tchar</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.36"><b>3.2.3</b></a></li>
     3813                        <li><tt>TE</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.97"><b>9.5</b></a></li>
     3814                        <li><tt>te-ext</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.100"><b>9.5</b></a></li>
     3815                        <li><tt>te-params</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.99"><b>9.5</b></a></li>
     3816                        <li><tt>time-of-day</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.57"><b>6.1</b></a></li>
     3817                        <li><tt>token</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.35"><b>3.2.3</b></a></li>
     3818                        <li><tt>Trailer</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.101"><b>9.6</b></a></li>
     3819                        <li><tt>trailer-part</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.85"><b>6.2.1</b></a></li>
     3820                        <li><tt>transfer-coding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.70"><b>6.2</b></a></li>
     3821                        <li><tt>Transfer-Encoding</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.102"><b>9.7</b></a></li>
     3822                        <li><tt>transfer-extension</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.71"><b>6.2</b></a></li>
     3823                        <li><tt>transfer-parameter</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.72"><b>6.2</b></a></li>
     3824                        <li><tt>Upgrade</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.103"><b>9.8</b></a></li>
    38153825                        <li><tt>uri-host</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.25"><b>2.7</b></a></li>
    38163826                        <li><tt>URI-reference</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.19"><b>2.7</b></a></li>
    3817                         <li><tt>value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.73"><b>6.2</b></a></li>
     3827                        <li><tt>value</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.74"><b>6.2</b></a></li>
    38183828                        <li>VCHAR&nbsp;&nbsp;<a href="#rfc.iref.g.12"><b>1.2</b></a></li>
    3819                         <li><tt>Via</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.103"><b>9.9</b></a></li>
    3820                         <li><tt>word</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.33"><b>3.2.3</b></a></li>
    3821                         <li><tt>year</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.64"><b>6.1</b></a></li>
     3829                        <li><tt>Via</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.104"><b>9.9</b></a></li>
     3830                        <li><tt>word</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.34"><b>3.2.3</b></a></li>
     3831                        <li><tt>year</tt>&nbsp;&nbsp;<a href="#rfc.iref.g.65"><b>6.1</b></a></li>
    38223832                     </ul>
    38233833                  </li>
    3824                   <li>gzip (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.g.87">6.2.2.3</a></li>
     3834                  <li>gzip (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.g.88">6.2.2.3</a></li>
    38253835               </ul>
    38263836            </li>
    … …  
    38293839                  <li>Header Fields&nbsp;&nbsp;
    38303840                     <ul>
    3831                         <li>Connection&nbsp;&nbsp;<a href="#rfc.xref.header.connection.1">2.4</a>, <a href="#rfc.xref.header.connection.2">2.6</a>, <a href="#rfc.xref.header.connection.3">3.2</a>, <a href="#rfc.xref.header.connection.4">3.5</a>, <a href="#rfc.xref.header.connection.5">7.1.2</a>, <a href="#rfc.xref.header.connection.6">7.1.3</a>, <a href="#rfc.xref.header.connection.7">7.1.3.1</a>, <a href="#rfc.iref.h.6"><b>9.1</b></a>, <a href="#rfc.xref.header.connection.8">9.5</a>, <a href="#rfc.xref.header.connection.9">9.8</a>, <a href="#rfc.xref.header.connection.10">10.1</a>, <a href="#rfc.xref.header.connection.11">10.1</a>, <a href="#rfc.xref.header.connection.12">A.1.2</a>, <a href="#rfc.xref.header.connection.13">A.2</a></li>
    3832                         <li>Content-Length&nbsp;&nbsp;<a href="#rfc.xref.header.content-length.1">3.3</a>, <a href="#rfc.iref.h.7"><b>9.2</b></a>, <a href="#rfc.xref.header.content-length.2">10.1</a></li>
    3833                         <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.2</a>, <a href="#rfc.xref.header.date.2">3.5</a>, <a href="#rfc.iref.h.8"><b>9.3</b></a>, <a href="#rfc.xref.header.date.3">10.1</a></li>
    3834                         <li>Host&nbsp;&nbsp;<a href="#rfc.xref.header.host.1">4.3</a>, <a href="#rfc.iref.h.10"><b>9.4</b></a>, <a href="#rfc.xref.header.host.2">10.1</a>, <a href="#rfc.xref.header.host.3">A.1.1</a></li>
    3835                         <li>TE&nbsp;&nbsp;<a href="#rfc.xref.header.te.1">6.2</a>, <a href="#rfc.xref.header.te.2">6.2.1</a>, <a href="#rfc.xref.header.te.3">6.4</a>, <a href="#rfc.iref.h.11"><b>9.5</b></a>, <a href="#rfc.xref.header.te.4">10.1</a></li>
    3836                         <li>Trailer&nbsp;&nbsp;<a href="#rfc.xref.header.trailer.1">3.5</a>, <a href="#rfc.xref.header.trailer.2">6.2.1</a>, <a href="#rfc.iref.h.12"><b>9.6</b></a>, <a href="#rfc.xref.header.trailer.3">10.1</a></li>
    3837                         <li>Transfer-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.transfer-encoding.1">3.3</a>, <a href="#rfc.xref.header.transfer-encoding.2">3.5</a>, <a href="#rfc.xref.header.transfer-encoding.3">6.2</a>, <a href="#rfc.iref.h.13"><b>9.7</b></a>, <a href="#rfc.xref.header.transfer-encoding.4">10.1</a></li>
    3838                         <li>Upgrade&nbsp;&nbsp;<a href="#rfc.xref.header.upgrade.1">3.5</a>, <a href="#rfc.iref.h.14"><b>9.8</b></a>, <a href="#rfc.xref.header.upgrade.2">10.1</a>, <a href="#rfc.xref.header.upgrade.3">A.2</a></li>
    3839                         <li>Via&nbsp;&nbsp;<a href="#rfc.xref.header.via.1">2.4</a>, <a href="#rfc.xref.header.via.2">3.5</a>, <a href="#rfc.iref.h.15"><b>9.9</b></a>, <a href="#rfc.xref.header.via.3">10.1</a></li>
     3841                        <li>Connection&nbsp;&nbsp;<a href="#rfc.xref.header.connection.1">2.4</a>, <a href="#rfc.xref.header.connection.2">2.6</a>, <a href="#rfc.xref.header.connection.3">3.2</a>, <a href="#rfc.xref.header.connection.4">7.1.2</a>, <a href="#rfc.xref.header.connection.5">7.1.3</a>, <a href="#rfc.xref.header.connection.6">7.1.3.1</a>, <a href="#rfc.xref.header.connection.7">9</a>, <a href="#rfc.iref.h.6"><b>9.1</b></a>, <a href="#rfc.xref.header.connection.8">9.5</a>, <a href="#rfc.xref.header.connection.9">9.8</a>, <a href="#rfc.xref.header.connection.10">10.1</a>, <a href="#rfc.xref.header.connection.11">10.1</a>, <a href="#rfc.xref.header.connection.12">A.1.2</a>, <a href="#rfc.xref.header.connection.13">A.2</a></li>
     3842                        <li>Content-Length&nbsp;&nbsp;<a href="#rfc.xref.header.content-length.1">3.3</a>, <a href="#rfc.xref.header.content-length.2">9</a>, <a href="#rfc.iref.h.7"><b>9.2</b></a>, <a href="#rfc.xref.header.content-length.3">10.1</a></li>
     3843                        <li>Date&nbsp;&nbsp;<a href="#rfc.xref.header.date.1">3.2</a>, <a href="#rfc.xref.header.date.2">9</a>, <a href="#rfc.iref.h.8"><b>9.3</b></a>, <a href="#rfc.xref.header.date.3">10.1</a></li>
     3844                        <li>Host&nbsp;&nbsp;<a href="#rfc.xref.header.host.1">4.3</a>, <a href="#rfc.xref.header.host.2">9</a>, <a href="#rfc.iref.h.10"><b>9.4</b></a>, <a href="#rfc.xref.header.host.3">10.1</a>, <a href="#rfc.xref.header.host.4">A.1.1</a></li>
     3845                        <li>TE&nbsp;&nbsp;<a href="#rfc.xref.header.te.1">6.2</a>, <a href="#rfc.xref.header.te.2">6.2.1</a>, <a href="#rfc.xref.header.te.3">6.4</a>, <a href="#rfc.xref.header.te.4">9</a>, <a href="#rfc.iref.h.11"><b>9.5</b></a>, <a href="#rfc.xref.header.te.5">10.1</a></li>
     3846                        <li>Trailer&nbsp;&nbsp;<a href="#rfc.xref.header.trailer.1">6.2.1</a>, <a href="#rfc.xref.header.trailer.2">9</a>, <a href="#rfc.iref.h.12"><b>9.6</b></a>, <a href="#rfc.xref.header.trailer.3">10.1</a></li>
     3847                        <li>Transfer-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.transfer-encoding.1">3.3</a>, <a href="#rfc.xref.header.transfer-encoding.2">6.2</a>, <a href="#rfc.xref.header.transfer-encoding.3">9</a>, <a href="#rfc.iref.h.13"><b>9.7</b></a>, <a href="#rfc.xref.header.transfer-encoding.4">10.1</a></li>
     3848                        <li>Upgrade&nbsp;&nbsp;<a href="#rfc.xref.header.upgrade.1">9</a>, <a href="#rfc.iref.h.14"><b>9.8</b></a>, <a href="#rfc.xref.header.upgrade.2">10.1</a>, <a href="#rfc.xref.header.upgrade.3">A.2</a></li>
     3849                        <li>Via&nbsp;&nbsp;<a href="#rfc.xref.header.via.1">2.4</a>, <a href="#rfc.xref.header.via.2">9</a>, <a href="#rfc.iref.h.15"><b>9.9</b></a>, <a href="#rfc.xref.header.via.3">10.1</a></li>
    38403850                     </ul>
    38413851                  </li>
    38423852                  <li>header section&nbsp;&nbsp;<a href="#rfc.iref.h.3">3</a></li>
    38433853                  <li>headers&nbsp;&nbsp;<a href="#rfc.iref.h.4">3</a></li>
    3844                   <li>Host header field&nbsp;&nbsp;<a href="#rfc.xref.header.host.1">4.3</a>, <a href="#rfc.iref.h.9"><b>9.4</b></a>, <a href="#rfc.xref.header.host.2">10.1</a>, <a href="#rfc.xref.header.host.3">A.1.1</a></li>
     3854                  <li>Host header field&nbsp;&nbsp;<a href="#rfc.xref.header.host.1">4.3</a>, <a href="#rfc.xref.header.host.2">9</a>, <a href="#rfc.iref.h.9"><b>9.4</b></a>, <a href="#rfc.xref.header.host.3">10.1</a>, <a href="#rfc.xref.header.host.4">A.1.1</a></li>
    38453855                  <li>http URI scheme&nbsp;&nbsp;<a href="#rfc.iref.h.1"><b>2.7.1</b></a></li>
    38463856                  <li>https URI scheme&nbsp;&nbsp;<a href="#rfc.iref.h.2">2.7.2</a></li>
    … …  
    39964006            <li><a id="rfc.index.T" href="#rfc.index.T"><b>T</b></a><ul>
    39974007                  <li>target resource&nbsp;&nbsp;<a href="#rfc.iref.t.4"><b>4.3</b></a></li>
    3998                   <li>TE header field&nbsp;&nbsp;<a href="#rfc.xref.header.te.1">6.2</a>, <a href="#rfc.xref.header.te.2">6.2.1</a>, <a href="#rfc.xref.header.te.3">6.4</a>, <a href="#rfc.iref.t.5"><b>9.5</b></a>, <a href="#rfc.xref.header.te.4">10.1</a></li>
     4008                  <li>TE header field&nbsp;&nbsp;<a href="#rfc.xref.header.te.1">6.2</a>, <a href="#rfc.xref.header.te.2">6.2.1</a>, <a href="#rfc.xref.header.te.3">6.4</a>, <a href="#rfc.xref.header.te.4">9</a>, <a href="#rfc.iref.t.5"><b>9.5</b></a>, <a href="#rfc.xref.header.te.5">10.1</a></li>
    39994009                  <li><em>Tou1998</em>&nbsp;&nbsp;<a href="#rfc.xref.Tou1998.1">7.1.1</a>, <a href="#Tou1998"><b>13.2</b></a></li>
    4000                   <li>Trailer header field&nbsp;&nbsp;<a href="#rfc.xref.header.trailer.1">3.5</a>, <a href="#rfc.xref.header.trailer.2">6.2.1</a>, <a href="#rfc.iref.t.6"><b>9.6</b></a>, <a href="#rfc.xref.header.trailer.3">10.1</a></li>
    4001                   <li>Transfer-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.transfer-encoding.1">3.3</a>, <a href="#rfc.xref.header.transfer-encoding.2">3.5</a>, <a href="#rfc.xref.header.transfer-encoding.3">6.2</a>, <a href="#rfc.iref.t.7"><b>9.7</b></a>, <a href="#rfc.xref.header.transfer-encoding.4">10.1</a></li>
     4010                  <li>Trailer header field&nbsp;&nbsp;<a href="#rfc.xref.header.trailer.1">6.2.1</a>, <a href="#rfc.xref.header.trailer.2">9</a>, <a href="#rfc.iref.t.6"><b>9.6</b></a>, <a href="#rfc.xref.header.trailer.3">10.1</a></li>
     4011                  <li>Transfer-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.transfer-encoding.1">3.3</a>, <a href="#rfc.xref.header.transfer-encoding.2">6.2</a>, <a href="#rfc.xref.header.transfer-encoding.3">9</a>, <a href="#rfc.iref.t.7"><b>9.7</b></a>, <a href="#rfc.xref.header.transfer-encoding.4">10.1</a></li>
    40024012                  <li>transforming proxy&nbsp;&nbsp;<a href="#rfc.iref.t.1"><b>2.4</b></a></li>
    40034013                  <li>transparent proxy&nbsp;&nbsp;<a href="#rfc.iref.t.3"><b>2.4</b></a></li>
    … …  
    40064016            </li>
    40074017            <li><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul>
    4008                   <li>Upgrade header field&nbsp;&nbsp;<a href="#rfc.xref.header.upgrade.1">3.5</a>, <a href="#rfc.iref.u.5"><b>9.8</b></a>, <a href="#rfc.xref.header.upgrade.2">10.1</a>, <a href="#rfc.xref.header.upgrade.3">A.2</a></li>
     4018                  <li>Upgrade header field&nbsp;&nbsp;<a href="#rfc.xref.header.upgrade.1">9</a>, <a href="#rfc.iref.u.5"><b>9.8</b></a>, <a href="#rfc.xref.header.upgrade.2">10.1</a>, <a href="#rfc.xref.header.upgrade.3">A.2</a></li>
    40094019                  <li>upstream&nbsp;&nbsp;<a href="#rfc.iref.u.2"><b>2.4</b></a></li>
    40104020                  <li>URI scheme&nbsp;&nbsp;
    … …  
    40144024                     </ul>
    40154025                  </li>
    4016                   <li><em>USASCII</em>&nbsp;&nbsp;<a href="#rfc.xref.USASCII.1">1.2</a>, <a href="#rfc.xref.USASCII.2">3.1</a>, <a href="#rfc.xref.USASCII.3">3.2.1</a>, <a href="#USASCII"><b>13.1</b></a></li>
     4026                  <li><em>USASCII</em>&nbsp;&nbsp;<a href="#rfc.xref.USASCII.1">1.2</a>, <a href="#rfc.xref.USASCII.2">3</a>, <a href="#rfc.xref.USASCII.3">3.2.1</a>, <a href="#USASCII"><b>13.1</b></a></li>
    40174027                  <li>user agent&nbsp;&nbsp;<a href="#rfc.iref.u.1"><b>2.1</b></a></li>
    40184028               </ul>
    40194029            </li>
    40204030            <li><a id="rfc.index.V" href="#rfc.index.V"><b>V</b></a><ul>
    4021                   <li>Via header field&nbsp;&nbsp;<a href="#rfc.xref.header.via.1">2.4</a>, <a href="#rfc.xref.header.via.2">3.5</a>, <a href="#rfc.iref.v.1"><b>9.9</b></a>, <a href="#rfc.xref.header.via.3">10.1</a></li>
     4031                  <li>Via header field&nbsp;&nbsp;<a href="#rfc.xref.header.via.1">2.4</a>, <a href="#rfc.xref.header.via.2">9</a>, <a href="#rfc.iref.v.1"><b>9.9</b></a>, <a href="#rfc.xref.header.via.3">10.1</a></li>
    40224032               </ul>
    40234033            </li>

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

    r1427 r1431  
    478478</section>
    479479
    480 <section title="HTTP-related architecture" anchor="architecture">
     480<section title="Architecture" anchor="architecture">
    481481<t>
    482482   HTTP was created for the World Wide Web architecture
    … …  
    11351135   indicating the end of the header section, and an optional message-body.
    11361136</t>
     1137<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="HTTP-message"/>
     1138  <x:ref>HTTP-message</x:ref>    = <x:ref>start-line</x:ref>
     1139                    *( <x:ref>header-field</x:ref> <x:ref>CRLF</x:ref> )
     1140                    <x:ref>CRLF</x:ref>
     1141                    [ <x:ref>message-body</x:ref> ]
     1142</artwork></figure>
     1143<t>
     1144   The normal procedure for parsing an HTTP message is to read the
     1145   start-line into a structure, read each header field into a hash
     1146   table by field name until the empty line, and then use the parsed
     1147   data to determine if a message-body is expected.  If a message-body
     1148   has been indicated, then it is read as a stream until an amount
     1149   of octets equal to the message-body length is read or the connection
     1150   is closed.
     1151</t>
     1152<t>
     1153   Recipients &MUST; parse an HTTP message as a sequence of octets in an
     1154   encoding that is a superset of US-ASCII <xref target="USASCII"/>.
     1155   Parsing an HTTP message as a stream of Unicode characters, without regard
     1156   for the specific encoding, creates security vulnerabilities due to the
     1157   varying ways that string processing libraries handle invalid multibyte
     1158   character sequences that contain the octet LF (%x0A).  String-based
     1159   parsers can only be safely used within protocol elements after the element
     1160   has been extracted from the message, such as within a header field-value
     1161   after message parsing has delineated the individual fields.
     1162</t>
     1163
     1164<section anchor="start.line" title="Start Line">
    11371165<t>
    11381166   An HTTP message can either be a request from client to server or a
    … …  
    11471175   and clients are implemented to only expect a response.
    11481176</t>
    1149 <figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="HTTP-message"/>
    1150   <x:ref>HTTP-message</x:ref>    = <x:ref>start-line</x:ref>
    1151                     *( <x:ref>header-field</x:ref> <x:ref>CRLF</x:ref> )
    1152                     <x:ref>CRLF</x:ref>
    1153                     [ <x:ref>message-body</x:ref> ]
     1177<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="start-line"/>
    11541178  <x:ref>start-line</x:ref>      = <x:ref>Request-Line</x:ref> / <x:ref>Status-Line</x:ref>
    11551179</artwork></figure>
     1180<t>
     1181</t>
    11561182<t>
    11571183   Implementations &MUST-NOT; send whitespace between the start-line and
    … …  
    11631189   Likewise, the presence of such whitespace in a response might be
    11641190   ignored by some clients or cause others to cease parsing.
    1165 </t>
    1166 
    1167 <section title="Message Parsing and Robustness" anchor="message.robustness">
    1168 <t>
    1169    The normal procedure for parsing an HTTP message is to read the
    1170    start-line into a structure, read each header field into a hash
    1171    table by field name until the empty line, and then use the parsed
    1172    data to determine if a message-body is expected.  If a message-body
    1173    has been indicated, then it is read as a stream until an amount
    1174    of octets equal to the message-body length is read or the connection
    1175    is closed.
    1176 </t>
    1177 <t>
    1178    Recipients &MUST; parse an HTTP message as a sequence of octets in an
    1179    encoding that is a superset of US-ASCII <xref target="USASCII"/>.
    1180    Parsing an HTTP message as a stream of Unicode characters, without regard
    1181    for the specific encoding, creates security vulnerabilities due to the
    1182    varying ways that string processing libraries handle invalid multibyte
    1183    character sequences that contain the octet LF (%x0A).  String-based
    1184    parsers can only be safely used within protocol elements after the element
    1185    has been extracted from the message, such as within a header field-value
    1186    after message parsing has delineated the individual fields.
    1187 </t>
    1188 <t>
    1189    Older HTTP/1.0 client implementations might send an extra CRLF
    1190    after a POST request as a lame workaround for some early server
    1191    applications that failed to read message-body content that was
    1192    not terminated by a line-ending. An HTTP/1.1 client &MUST-NOT;
    1193    preface or follow a request with an extra CRLF.  If terminating
    1194    the request message-body with a line-ending is desired, then the
    1195    client &MUST; include the terminating CRLF octets as part of the
    1196    message-body length.
    1197 </t>
    1198 <t>
    1199    In the interest of robustness, servers &SHOULD; ignore at least one
    1200    empty line received where a Request-Line is expected. In other words, if
    1201    the server is reading the protocol stream at the beginning of a
    1202    message and receives a CRLF first, it &SHOULD; ignore the CRLF.
    1203    Likewise, although the line terminator for the start-line and header
    1204    fields is the sequence CRLF, we recommend that recipients recognize a
    1205    single LF as a line terminator and ignore any CR.
    1206 </t>
    1207 <t>
    1208    When a server listening only for HTTP request messages, or processing
    1209    what appears from the start-line to be an HTTP request message,
    1210    receives a sequence of octets that does not match the HTTP-message
    1211    grammar aside from the robustness exceptions listed above, the
    1212    server &MUST; respond with an HTTP/1.1 400 (Bad Request) response. 
    12131191</t>
    12141192</section>
    … …  
    16041582</section>
    16051583
    1606 <section anchor="incomplete.messages" title="Incomplete Messages">
     1584<section anchor="incomplete.messages" title="Handling Incomplete Messages">
    16071585<t>
    16081586   Request messages that are prematurely terminated, possibly due to a
    … …  
    16471625</section>
    16481626
    1649 <section title="General Header Fields" anchor="general.header.fields">
    1650   <x:anchor-alias value="general-header"/>
    1651 <t>
    1652    There are a few header fields which have general applicability for
    1653    both request and response messages, but which do not apply to the
    1654    payload being transferred. These header fields apply only to the
    1655    message being transmitted.
    1656 </t>
    1657 <texttable align="left">
    1658   <ttcol>Header Field Name</ttcol>
    1659   <ttcol>Defined in...</ttcol>
    1660  
    1661   <c>Connection</c> <c><xref target="header.connection"/></c>
    1662   <c>Date</c> <c><xref target="header.date"/></c>
    1663   <c>Trailer</c> <c><xref target="header.trailer"/></c>
    1664   <c>Transfer-Encoding</c> <c><xref target="header.transfer-encoding"/></c>
    1665   <c>Upgrade</c> <c><xref target="header.upgrade"/></c>
    1666   <c>Via</c> <c><xref target="header.via"/></c>
    1667 </texttable>
     1627<section title="Message Parsing Robustness" anchor="message.robustness">
     1628<t>
     1629   Older HTTP/1.0 client implementations might send an extra CRLF
     1630   after a POST request as a lame workaround for some early server
     1631   applications that failed to read message-body content that was
     1632   not terminated by a line-ending. An HTTP/1.1 client &MUST-NOT;
     1633   preface or follow a request with an extra CRLF.  If terminating
     1634   the request message-body with a line-ending is desired, then the
     1635   client &MUST; include the terminating CRLF octets as part of the
     1636   message-body length.
     1637</t>
     1638<t>
     1639   In the interest of robustness, servers &SHOULD; ignore at least one
     1640   empty line received where a Request-Line is expected. In other words, if
     1641   the server is reading the protocol stream at the beginning of a
     1642   message and receives a CRLF first, it &SHOULD; ignore the CRLF.
     1643   Likewise, although the line terminator for the start-line and header
     1644   fields is the sequence CRLF, we recommend that recipients recognize a
     1645   single LF as a line terminator and ignore any CR.
     1646</t>
     1647<t>
     1648   When a server listening only for HTTP request messages, or processing
     1649   what appears from the start-line to be an HTTP request message,
     1650   receives a sequence of octets that does not match the HTTP-message
     1651   grammar aside from the robustness exceptions listed above, the
     1652   server &MUST; respond with an HTTP/1.1 400 (Bad Request) response. 
     1653</t>
    16681654</section>
    16691655</section>
    … …  
    30813067<t>
    30823068   This section defines the syntax and semantics of HTTP header fields
    3083    related to message framing and transport protocols.
    3084 </t>
     3069   related to message origination, framing, and routing.
     3070</t>
     3071<texttable align="left">
     3072  <ttcol>Header Field Name</ttcol>
     3073  <ttcol>Defined in...</ttcol>
     3074 
     3075  <c>Connection</c> <c><xref target="header.connection"/></c>
     3076  <c>Content-Length</c> <c><xref target="header.content-length"/></c>
     3077  <c>Date</c> <c><xref target="header.date"/></c>
     3078  <c>Host</c> <c><xref target="header.host"/></c>
     3079  <c>TE</c> <c><xref target="header.te"/></c>
     3080  <c>Trailer</c> <c><xref target="header.trailer"/></c>
     3081  <c>Transfer-Encoding</c> <c><xref target="header.transfer-encoding"/></c>
     3082  <c>Upgrade</c> <c><xref target="header.upgrade"/></c>
     3083  <c>Via</c> <c><xref target="header.via"/></c>
     3084</texttable>
    30853085
    30863086<section title="Connection" anchor="header.connection">
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