Changeset 1847
- Timestamp:
- 02/09/12 05:22:28 (10 years ago)
- Location:
- draft-ietf-httpbis/latest
- Files:
-
- 2 edited
Legend:
- Unmodified
- Added
- Removed
-
draft-ietf-httpbis/latest/p2-semantics.html
r1846 r1847 612 612 <li><a href="#rfc.section.4.3">4.3</a> <a href="#resource.fields">Resource Metadata Fields</a></li> 613 613 <li><a href="#rfc.section.4.4">4.4</a> <a href="#payload.fields">Payload Metadata Fields</a></li> 614 <li><a href="#rfc.section.4.5">4.5</a> <a href="#considerations.for.creating.header.fields">Considerations for Creating Header Fields</a></li> 615 <li><a href="#rfc.section.4.6">4.6</a> <a href="#request.header.fields">Request Header Fields</a></li> 616 <li><a href="#rfc.section.4.7">4.7</a> <a href="#response.header.fields">Response Header Fields</a></li> 614 <li><a href="#rfc.section.4.5">4.5</a> <a href="#request.header.fields">Request Header Fields</a></li> 615 <li><a href="#rfc.section.4.6">4.6</a> <a href="#response.header.fields">Response Header Fields</a></li> 617 616 </ul> 618 617 </li> … … 736 735 </ul> 737 736 </li> 738 <li><a href="#rfc.section.11.3">11.3</a> <a href="#header.field.registration">Header Field Registration</a></li> 737 <li><a href="#rfc.section.11.3">11.3</a> <a href="#header.field.registry">Header Field Registry</a><ul> 738 <li><a href="#rfc.section.11.3.1">11.3.1</a> <a href="#considerations.for.new.header.fields">Considerations for New Header Fields</a></li> 739 <li><a href="#rfc.section.11.3.2">11.3.2</a> <a href="#header.field.registration">Registrations</a></li> 740 </ul> 741 </li> 739 742 <li><a href="#rfc.section.11.4">11.4</a> <a href="#content.coding.registry">Content Coding Registry</a><ul> 740 743 <li><a href="#rfc.section.11.4.1">11.4.1</a> <a href="#content.coding.procedure">Procedure</a></li> … … 1204 1207 <h2 id="rfc.section.4.3"><a href="#rfc.section.4.3">4.3</a> <a id="resource.fields" href="#resource.fields">Resource Metadata Fields</a></h2> 1205 1208 <h2 id="rfc.section.4.4"><a href="#rfc.section.4.4">4.4</a> <a id="payload.fields" href="#payload.fields">Payload Metadata Fields</a></h2> 1206 <h2 id="rfc.section.4.5"><a href="#rfc.section.4.5">4.5</a> <a id="considerations.for.creating.header.fields" href="#considerations.for.creating.header.fields">Considerations for Creating Header Fields</a></h2> 1207 <p id="rfc.section.4.5.p.1">New header fields are registered using the procedures described in <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>. 1208 </p> 1209 <p id="rfc.section.4.5.p.2">The requirements for header field names are defined in <a href="http://tools.ietf.org/html/rfc3864#section-4.1">Section 4.1</a> of <a href="#RFC3864" id="rfc.xref.RFC3864.2"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>. Authors of specifications defining new fields are advised to keep the name as short as practical, and not to prefix them 1210 with "X-" if they are to be registered (either immediately or in the future). 1211 </p> 1212 <p id="rfc.section.4.5.p.3">New header field values typically have their syntax defined using ABNF (<a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>), using the extension defined in <a href="p1-messaging.html#abnf.extension" title="ABNF list extension: #rule">Appendix B</a> of <a href="#Part1" id="rfc.xref.Part1.12"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a> as necessary, and are usually constrained to the range of ASCII characters. Header fields needing a greater range of characters 1213 can use an encoding such as the one defined in <a href="#RFC5987" id="rfc.xref.RFC5987.1"><cite title="Character Set and Language Encoding for Hypertext Transfer Protocol (HTTP) Header Field Parameters">[RFC5987]</cite></a>. 1214 </p> 1215 <p id="rfc.section.4.5.p.4">Because commas (",") are used as a generic delimiter between field-values, they need to be treated with care if they are allowed 1216 in the field-value's payload. Typically, components that might contain a comma are protected with double-quotes using the 1217 quoted-string ABNF production (<a href="p1-messaging.html#field.components" title="Field value components">Section 3.2.4</a> of <a href="#Part1" id="rfc.xref.Part1.13"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 1218 </p> 1219 <p id="rfc.section.4.5.p.5">For example, a textual date and a URI (either of which might contain a comma) could be safely carried in field-values like 1220 these: 1221 </p> 1222 <div id="rfc.figure.u.4"></div><pre class="text"> Example-URI-Field: "http://example.com/a.html,foo", 1223 "http://without-a-comma.example.com/" 1224 Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005" 1225 </pre><p id="rfc.section.4.5.p.7">Note that double quote delimiters almost always are used with the quoted-string production; using a different syntax inside 1226 double quotes will likely cause unnecessary confusion. 1227 </p> 1228 <p id="rfc.section.4.5.p.8">Many header fields use a format including (case-insensitively) named parameters (for instance, <a href="#header.content-type" class="smpl">Content-Type</a>, defined in <a href="#header.content-type" id="rfc.xref.header.content-type.1" title="Content-Type">Section 10.9</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing 1229 parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for 1230 it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Section 6.5</a>). 1231 </p> 1232 <p id="rfc.section.4.5.p.9">Authors of specifications defining new header fields are advised to consider documenting: </p> 1233 <ul> 1234 <li> 1235 <p>Whether the field is a single value, or whether it can be a list (delimited by commas; see <a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.14"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 1236 </p> 1237 <p>If it does not use the list syntax, document how to treat messages where the header field occurs multiple times (a sensible 1238 default would be to ignore the header field, but this might not always be the right choice). 1239 </p> 1240 <p>Note that intermediaries and software libraries might combine multiple header field instances into a single one, despite the 1241 header field not allowing this. A robust format enables recipients to discover these situations (good example: "Content-Type", 1242 as the comma can only appear inside quoted strings; bad example: "Location", as a comma can occur inside a URI). 1243 </p> 1244 </li> 1245 <li> 1246 <p>Under what conditions the header field can be used; e.g., only in responses or requests, in all messages, only on responses 1247 to a particular request method. 1248 </p> 1249 </li> 1250 <li> 1251 <p>Whether it is appropriate to list the field-name in the <a href="p1-messaging.html#header.connection" class="smpl">Connection</a> header field (i.e., if the header field is to be hop-by-hop, see <a href="p1-messaging.html#header.connection" title="Connection">Section 6.1</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 1252 </p> 1253 </li> 1254 <li> 1255 <p>Under what conditions intermediaries are allowed to modify the header field's value, insert or delete it.</p> 1256 </li> 1257 <li> 1258 <p>How the header field might interact with caching (see <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). 1259 </p> 1260 </li> 1261 <li> 1262 <p>Whether the header field is useful or allowable in trailers (see <a href="p1-messaging.html#chunked.encoding" title="Chunked Transfer Coding">Section 4.1</a> of <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 1263 </p> 1264 </li> 1265 <li> 1266 <p>Whether the header field ought to be preserved across redirects.</p> 1267 </li> 1268 </ul> 1269 <h2 id="rfc.section.4.6"><a href="#rfc.section.4.6">4.6</a> <a id="request.header.fields" href="#request.header.fields">Request Header Fields</a></h2> 1270 <p id="rfc.section.4.6.p.1">The request header fields allow the client to pass additional information about the request, and about the client itself, 1209 <h2 id="rfc.section.4.5"><a href="#rfc.section.4.5">4.5</a> <a id="request.header.fields" href="#request.header.fields">Request Header Fields</a></h2> 1210 <p id="rfc.section.4.5.p.1">The request header fields allow the client to pass additional information about the request, and about the client itself, 1271 1211 to the server. These fields act as request modifiers, with semantics equivalent to the parameters on a programming language 1272 1212 method invocation. … … 1311 1251 <tr> 1312 1252 <td class="left">Host</td> 1313 <td class="left"><a href="p1-messaging.html#header.host" title="Host">Section 5.4</a> of <a href="#Part1" id="rfc.xref.Part1.1 7"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a></td>1253 <td class="left"><a href="p1-messaging.html#header.host" title="Host">Section 5.4</a> of <a href="#Part1" id="rfc.xref.Part1.12"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a></td> 1314 1254 </tr> 1315 1255 <tr> … … 1351 1291 <tr> 1352 1292 <td class="left">TE</td> 1353 <td class="left"><a href="p1-messaging.html#header.te" title="TE">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.1 8"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a></td>1293 <td class="left"><a href="p1-messaging.html#header.te" title="TE">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.13"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a></td> 1354 1294 </tr> 1355 1295 <tr> … … 1360 1300 </table> 1361 1301 </div> 1362 <h2 id="rfc.section.4. 7"><a href="#rfc.section.4.7">4.7</a> <a id="response.header.fields" href="#response.header.fields">Response Header Fields</a></h2>1363 <p id="rfc.section.4. 7.p.1">The response header fields allow the server to pass additional information about the response which cannot be placed in the1364 status-line. These header fields give information about the server and about further access to the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.1 9"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>).1302 <h2 id="rfc.section.4.6"><a href="#rfc.section.4.6">4.6</a> <a id="response.header.fields" href="#response.header.fields">Response Header Fields</a></h2> 1303 <p id="rfc.section.4.6.p.1">The response header fields allow the server to pass additional information about the response which cannot be placed in the 1304 status-line. These header fields give information about the server and about further access to the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.14"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 1365 1305 </p> 1366 1306 <div id="rfc.table.u.2"> … … 1379 1319 <tr> 1380 1320 <td class="left">Age</td> 1381 <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 7.1</a> of <a href="#Part6" id="rfc.xref.Part6. 8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>1321 <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 7.1</a> of <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td> 1382 1322 </tr> 1383 1323 <tr> … … 1411 1351 <tr> 1412 1352 <td class="left">Vary</td> 1413 <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6. 9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>1353 <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td> 1414 1354 </tr> 1415 1355 <tr> … … 1443 1383 </li> 1444 1384 </ul> 1445 <p id="rfc.section.5.p.4">For most status codes the response can carry a payload, in which case a <a href="#header.content-type" class="smpl">Content-Type</a> header field indicates the payload's media type (<a href="#header.content-type" id="rfc.xref.header.content-type. 2" title="Content-Type">Section 10.9</a>).1385 <p id="rfc.section.5.p.4">For most status codes the response can carry a payload, in which case a <a href="#header.content-type" class="smpl">Content-Type</a> header field indicates the payload's media type (<a href="#header.content-type" id="rfc.xref.header.content-type.1" title="Content-Type">Section 10.9</a>). 1446 1386 </p> 1447 1387 <h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a> <a id="overview.of.status.codes" href="#overview.of.status.codes">Overview of Status Codes</a></h2> … … 1687 1627 <p id="rfc.section.5.2.1.p.1">The client <em class="bcp14">SHOULD</em> continue with its request. This interim response is used to inform the client that the initial part of the request has been 1688 1628 received and has not yet been rejected by the server. The client <em class="bcp14">SHOULD</em> continue by sending the remainder of the request or, if the request has already been completed, ignore this response. The 1689 server <em class="bcp14">MUST</em> send a final response after the request has been completed. See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1. 20"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a> for detailed discussion of the use and handling of this status code.1629 server <em class="bcp14">MUST</em> send a final response after the request has been completed. See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a> for detailed discussion of the use and handling of this status code. 1690 1630 </p> 1691 1631 <div id="rfc.iref.23"></div> 1692 1632 <div id="rfc.iref.s.4"></div> 1693 1633 <h3 id="rfc.section.5.2.2"><a href="#rfc.section.5.2.2">5.2.2</a> <a id="status.101" href="#status.101">101 Switching Protocols</a></h3> 1694 <p id="rfc.section.5.2.2.p.1">The server understands and is willing to comply with the client's request, via the <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> message header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1. 21"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>), for a change in the application protocol being used on this connection. The server will switch protocols to those defined1634 <p id="rfc.section.5.2.2.p.1">The server understands and is willing to comply with the client's request, via the <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> message header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>), for a change in the application protocol being used on this connection. The server will switch protocols to those defined 1695 1635 by the response's Upgrade header field immediately after the empty line which terminates the 101 response. 1696 1636 </p> … … 1717 1657 <dd>a representation containing the request message as received by the end server.</dd> 1718 1658 </dl> 1719 <p id="rfc.section.5.3.1.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6. 10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses.1659 <p id="rfc.section.5.3.1.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses. 1720 1660 </p> 1721 1661 <div id="rfc.iref.26"></div> … … 1747 1687 <div id="rfc.iref.s.9"></div> 1748 1688 <h3 id="rfc.section.5.3.4"><a href="#rfc.section.5.3.4">5.3.4</a> <a id="status.203" href="#status.203">203 Non-Authoritative Information</a></h3> 1749 <p id="rfc.section.5.3.4.p.1">The representation in the response has been transformed or otherwise modified by a transforming proxy (<a href="p1-messaging.html#intermediaries" title="Intermediaries">Section 2.3</a> of <a href="#Part1" id="rfc.xref.Part1. 22"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). Note that the behavior of transforming intermediaries is controlled by the no-transform Cache-Control directive (<a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 7.2</a> of <a href="#Part6" id="rfc.xref.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).1689 <p id="rfc.section.5.3.4.p.1">The representation in the response has been transformed or otherwise modified by a transforming proxy (<a href="p1-messaging.html#intermediaries" title="Intermediaries">Section 2.3</a> of <a href="#Part1" id="rfc.xref.Part1.17"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). Note that the behavior of transforming intermediaries is controlled by the no-transform Cache-Control directive (<a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 7.2</a> of <a href="#Part6" id="rfc.xref.Part6.10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). 1750 1690 </p> 1751 1691 <p id="rfc.section.5.3.4.p.2">This status code is only appropriate when the response status code would have been <a href="#status.200" class="smpl">200 (OK)</a> otherwise. When the status code before transformation would have been different, the 214 Transformation Applied warn-code 1752 (<a href="p6-cache.html#header.warning" title="Warning">Section 7.6</a> of <a href="#Part6" id="rfc.xref.Part6.1 2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate.1753 </p> 1754 <p id="rfc.section.5.3.4.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.1 3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses.1692 (<a href="p6-cache.html#header.warning" title="Warning">Section 7.6</a> of <a href="#Part6" id="rfc.xref.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate. 1693 </p> 1694 <p id="rfc.section.5.3.4.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.12"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses. 1755 1695 </p> 1756 1696 <div id="rfc.iref.29"></div> … … 1782 1722 another input action. 1783 1723 </p> 1784 <p id="rfc.section.5.3.6.p.2">The message body included with the response <em class="bcp14">MUST</em> be empty. Note that receivers still need to parse the response according to the algorithm defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1. 23"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>.1724 <p id="rfc.section.5.3.6.p.2">The message body included with the response <em class="bcp14">MUST</em> be empty. Note that receivers still need to parse the response according to the algorithm defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.18"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. 1785 1725 </p> 1786 1726 <h2 id="rfc.section.5.4"><a href="#rfc.section.5.4">5.4</a> <a id="status.3xx" href="#status.3xx">Redirection 3xx</a></h2> … … 1844 1784 <p id="rfc.section.5.4.1.p.3">If the server has a preferred choice of representation, it <em class="bcp14">SHOULD</em> include the specific URI for that representation in the <a href="#header.location" class="smpl">Location</a> field; user agents <em class="bcp14">MAY</em> use the Location field value for automatic redirection. 1845 1785 </p> 1846 <p id="rfc.section.5.4.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.1 4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses.1786 <p id="rfc.section.5.4.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.13"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses. 1847 1787 </p> 1848 1788 <div id="rfc.iref.33"></div> … … 1852 1792 request URI to one or more of the new references returned by the server, where possible. 1853 1793 </p> 1854 <p id="rfc.section.5.4.2.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.1 5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses.1794 <p id="rfc.section.5.4.2.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.14"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses. 1855 1795 </p> 1856 1796 <p id="rfc.section.5.4.2.p.3">The new permanent URI <em class="bcp14">SHOULD</em> be given by the <a href="#header.location" class="smpl">Location</a> field in the response. A response payload can contain a short hypertext note with a hyperlink to the new URI(s). … … 2001 1941 — that is left to the discretion of the server owner. 2002 1942 </p> 2003 <p id="rfc.section.5.5.9.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.1 6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses.1943 <p id="rfc.section.5.5.9.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 4.1.2</a> of <a href="#Part6" id="rfc.xref.Part6.15"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses. 2004 1944 </p> 2005 1945 <div id="rfc.iref.49"></div> … … 2041 1981 <div id="rfc.iref.s.35"></div> 2042 1982 <h3 id="rfc.section.5.5.15"><a href="#rfc.section.5.5.15">5.5.15</a> <a id="status.426" href="#status.426">426 Upgrade Required</a></h3> 2043 <p id="rfc.section.5.5.15.p.1">The request can not be completed without a prior protocol upgrade. This response <em class="bcp14">MUST</em> include an <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1. 24"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) specifying the required protocols.2044 </p> 2045 <div id="rfc.figure.u. 5"></div>1983 <p id="rfc.section.5.5.15.p.1">The request can not be completed without a prior protocol upgrade. This response <em class="bcp14">MUST</em> include an <a href="p1-messaging.html#header.upgrade" class="smpl">Upgrade</a> header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 6.4</a> of <a href="#Part1" id="rfc.xref.Part1.19"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) specifying the required protocols. 1984 </p> 1985 <div id="rfc.figure.u.4"></div> 2046 1986 <p>Example:</p> <pre class="text">HTTP/1.1 426 Upgrade Required 2047 1987 Upgrade: HTTP/3.0 … … 2106 2046 <p id="rfc.section.5.6.6.p.1">The server does not support, or refuses to support, the protocol version that was used in the request message. The server 2107 2047 is indicating that it is unable or unwilling to complete the request using the same major version as the client, as described 2108 in <a href="p1-messaging.html#http.version" title="Protocol Versioning">Section 2.6</a> of <a href="#Part1" id="rfc.xref.Part1.2 5"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>, other than with this error message. The response <em class="bcp14">SHOULD</em> contain a representation describing why that version is not supported and what other protocols are supported by that server.2048 in <a href="p1-messaging.html#http.version" title="Protocol Versioning">Section 2.6</a> of <a href="#Part1" id="rfc.xref.Part1.20"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>, other than with this error message. The response <em class="bcp14">SHOULD</em> contain a representation describing why that version is not supported and what other protocols are supported by that server. 2109 2049 </p> 2110 2050 <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a> <a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1> … … 2113 2053 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>: 2114 2054 </p> 2115 <div id="rfc.figure.u. 6"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT ; RFC 11232055 <div id="rfc.figure.u.5"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT ; RFC 1123 2116 2056 </pre><p id="rfc.section.6.1.p.3">The other formats are described here only for compatibility with obsolete implementations.</p> 2117 <div id="rfc.figure.u. 7"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format2057 <div id="rfc.figure.u.6"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format 2118 2058 Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format 2119 2059 </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. … … 2123 2063 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. 2124 2064 </p> 2125 <div id="rfc.figure.u. 8"></div><pre class="inline"><span id="rfc.iref.g.3"></span> <a href="#http.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>2065 <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.3"></span> <a href="#http.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> 2126 2066 </pre><div id="preferred.date.format"> 2127 2067 <p id="rfc.section.6.1.p.8"> Preferred format:</p> 2128 2068 </div> 2129 <div id="rfc.figure.u. 9"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span> <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#imported.abnf" class="smpl">SP</a> date1 <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>2069 <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span> <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#imported.abnf" class="smpl">SP</a> date1 <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a> 2130 2070 ; fixed length subset of the format defined in 2131 2071 ; <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> … … 2170 2110 <p id="rfc.section.6.1.p.11"> Obsolete formats:</p> 2171 2111 </div> 2172 <div id="rfc.figure.u. 10"></div><pre class="inline"><span id="rfc.iref.g.16"></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>2173 </pre><div id="rfc.figure.u.1 1"></div><pre class="inline"><span id="rfc.iref.g.17"></span> <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> = <a href="#obsolete.date.formats" class="smpl">day-name-l</a> "," <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date2</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>2112 <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.16"></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> 2113 </pre><div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.17"></span> <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> = <a href="#obsolete.date.formats" class="smpl">day-name-l</a> "," <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date2</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a> 2174 2114 <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="#imported.abnf" class="smpl">DIGIT</a> 2175 2115 ; day-month-year (e.g., 02-Jun-82) … … 2182 2122 / %x53.61.74.75.72.64.61.79 ; "Saturday", case-sensitive 2183 2123 / %x53.75.6E.64.61.79 ; "Sunday", case-sensitive 2184 </pre><div id="rfc.figure.u.1 2"></div><pre class="inline"><span id="rfc.iref.g.18"></span> <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date3</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">year</a>2124 </pre><div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.18"></span> <a href="#obsolete.date.formats" class="smpl">asctime-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#obsolete.date.formats" class="smpl">date3</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">year</a> 2185 2125 <a href="#obsolete.date.formats" class="smpl">date3</a> = <a href="#preferred.date.format" class="smpl">month</a> <a href="#imported.abnf" class="smpl">SP</a> ( 2<a href="#imported.abnf" class="smpl">DIGIT</a> / ( <a href="#imported.abnf" class="smpl">SP</a> 1<a href="#imported.abnf" class="smpl">DIGIT</a> )) 2186 2126 ; month day (e.g., Jun 2) … … 2200 2140 By convention, the products are listed in order of their significance for identifying the application. 2201 2141 </p> 2202 <div id="rfc.figure.u.1 3"></div><pre class="inline"><span id="rfc.iref.g.19"></span><span id="rfc.iref.g.20"></span> <a href="#product.tokens" class="smpl">product</a> = <a href="#imported.abnf" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>]2142 <div id="rfc.figure.u.12"></div><pre class="inline"><span id="rfc.iref.g.19"></span><span id="rfc.iref.g.20"></span> <a href="#product.tokens" class="smpl">product</a> = <a href="#imported.abnf" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>] 2203 2143 <a href="#product.tokens" class="smpl">product-version</a> = <a href="#imported.abnf" class="smpl">token</a> 2204 2144 </pre><p id="rfc.section.6.2.p.3">Examples:</p> 2205 <div id="rfc.figure.u.1 4"></div><pre class="text"> User-Agent: CERN-LineMode/2.15 libwww/2.17b32145 <div id="rfc.figure.u.13"></div><pre class="text"> User-Agent: CERN-LineMode/2.15 libwww/2.17b3 2206 2146 Server: Apache/0.8.4 2207 2147 </pre><p id="rfc.section.6.2.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). … … 2214 2154 </p> 2215 2155 </div> 2216 <div id="rfc.figure.u.1 5"></div><pre class="inline"><span id="rfc.iref.g.21"></span> <a href="#rule.charset" class="smpl">charset</a> = <a href="#imported.abnf" class="smpl">token</a>2156 <div id="rfc.figure.u.14"></div><pre class="inline"><span id="rfc.iref.g.21"></span> <a href="#rule.charset" class="smpl">charset</a> = <a href="#imported.abnf" class="smpl">token</a> 2217 2157 </pre><p id="rfc.section.6.3.p.4">Although HTTP allows an arbitrary token to be used as a charset value, any token that has a predefined value within the IANA 2218 2158 Character Set registry <em class="bcp14">MUST</em> represent the character encoding defined by that registry. Applications <em class="bcp14">SHOULD</em> limit their use of character encodings to those defined within the IANA registry. … … 2228 2168 directly, and only decoded by the recipient. 2229 2169 </p> 2230 <div id="rfc.figure.u.1 6"></div><pre class="inline"><span id="rfc.iref.g.22"></span> <a href="#content.codings" class="smpl">content-coding</a> = <a href="#imported.abnf" class="smpl">token</a>2170 <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.22"></span> <a href="#content.codings" class="smpl">content-coding</a> = <a href="#imported.abnf" class="smpl">token</a> 2231 2171 </pre><p id="rfc.section.6.4.p.3">All content-coding values are case-insensitive. HTTP/1.1 uses content-coding values in the <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.2" title="Accept-Encoding">Section 10.3</a>) and <a href="#header.content-encoding" class="smpl">Content-Encoding</a> (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Section 10.6</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding 2232 2172 mechanism will be required to remove the encoding. … … 2235 2175 </p> 2236 2176 <ul class="empty"> 2237 <li>See <a href="p1-messaging.html#compress.coding" title="Compress Coding">Section 4.2.1</a> of <a href="#Part1" id="rfc.xref.Part1.2 6"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>.2177 <li>See <a href="p1-messaging.html#compress.coding" title="Compress Coding">Section 4.2.1</a> of <a href="#Part1" id="rfc.xref.Part1.21"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. 2238 2178 </li> 2239 2179 </ul> … … 2241 2181 </p> 2242 2182 <ul class="empty"> 2243 <li>See <a href="p1-messaging.html#deflate.coding" title="Deflate Coding">Section 4.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.2 7"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>.2183 <li>See <a href="p1-messaging.html#deflate.coding" title="Deflate Coding">Section 4.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.22"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. 2244 2184 </li> 2245 2185 </ul> … … 2247 2187 </p> 2248 2188 <ul class="empty"> 2249 <li>See <a href="p1-messaging.html#gzip.coding" title="Gzip Coding">Section 4.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.2 8"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>.2189 <li>See <a href="p1-messaging.html#gzip.coding" title="Gzip Coding">Section 4.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.23"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. 2250 2190 </li> 2251 2191 </ul> 2252 2192 <h2 id="rfc.section.6.5"><a href="#rfc.section.6.5">6.5</a> <a id="media.types" href="#media.types">Media Types</a></h2> 2253 <p id="rfc.section.6.5.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> in the <a href="#header.content-type" class="smpl">Content-Type</a> (<a href="#header.content-type" id="rfc.xref.header.content-type. 3" title="Content-Type">Section 10.9</a>) and <a href="#header.accept" class="smpl">Accept</a> (<a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Section 10.1</a>) header fields in order to provide open and extensible data typing and type negotiation.2254 </p> 2255 <div id="rfc.figure.u.1 7"></div><pre class="inline"><span id="rfc.iref.g.24"></span><span id="rfc.iref.g.25"></span><span id="rfc.iref.g.26"></span> <a href="#media.types" class="smpl">media-type</a> = <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> *( <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> )2193 <p id="rfc.section.6.5.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> in the <a href="#header.content-type" class="smpl">Content-Type</a> (<a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Section 10.9</a>) and <a href="#header.accept" class="smpl">Accept</a> (<a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Section 10.1</a>) header fields in order to provide open and extensible data typing and type negotiation. 2194 </p> 2195 <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.24"></span><span id="rfc.iref.g.25"></span><span id="rfc.iref.g.26"></span> <a href="#media.types" class="smpl">media-type</a> = <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> *( <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">parameter</a> ) 2256 2196 <a href="#media.types" class="smpl">type</a> = <a href="#imported.abnf" class="smpl">token</a> 2257 2197 <a href="#media.types" class="smpl">subtype</a> = <a href="#imported.abnf" class="smpl">token</a> … … 2260 2200 </p> 2261 2201 </div> 2262 <div id="rfc.figure.u.1 8"></div><pre class="inline"><span id="rfc.iref.g.27"></span><span id="rfc.iref.g.28"></span><span id="rfc.iref.g.29"></span> <a href="#rule.parameter" class="smpl">parameter</a> = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a>2202 <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.27"></span><span id="rfc.iref.g.28"></span><span id="rfc.iref.g.29"></span> <a href="#rule.parameter" class="smpl">parameter</a> = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a> 2263 2203 <a href="#rule.parameter" class="smpl">attribute</a> = <a href="#imported.abnf" class="smpl">token</a> 2264 2204 <a href="#rule.parameter" class="smpl">value</a> = <a href="#imported.abnf" class="smpl">word</a> … … 2310 2250 of subtags: 2311 2251 </p> 2312 <div id="rfc.figure.u.1 9"></div><pre class="inline"><span id="rfc.iref.g.30"></span> <a href="#language.tags" class="smpl">language-tag</a> = <Language-Tag, defined in <a href="#RFC5646" id="rfc.xref.RFC5646.2"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a>, <a href="http://tools.ietf.org/html/rfc5646#section-2.1">Section 2.1</a>>2252 <div id="rfc.figure.u.18"></div><pre class="inline"><span id="rfc.iref.g.30"></span> <a href="#language.tags" class="smpl">language-tag</a> = <Language-Tag, defined in <a href="#RFC5646" id="rfc.xref.RFC5646.2"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a>, <a href="http://tools.ietf.org/html/rfc5646#section-2.1">Section 2.1</a>> 2313 2253 </pre><p id="rfc.section.6.6.p.4">White space is not allowed within the tag and all tags are case-insensitive. The name space of language subtags is administered 2314 2254 by the IANA (see <<a href="http://www.iana.org/assignments/language-subtag-registry">http://www.iana.org/assignments/language-subtag-registry</a>>). 2315 2255 </p> 2316 <div id="rfc.figure.u. 20"></div>2256 <div id="rfc.figure.u.19"></div> 2317 2257 <p>Example tags include:</p> <pre class="text"> en, en-US, es-419, az-Arab, x-pig-latin, man-Nkoo-GN 2318 2258 </pre> <p id="rfc.section.6.6.p.6">See <a href="#RFC5646" id="rfc.xref.RFC5646.3"><cite title="Tags for Identifying Languages">[RFC5646]</cite></a> for further information. … … 2343 2283 <tr> 2344 2284 <td class="left">Content-Length</td> 2345 <td class="left"><a href="p1-messaging.html#header.content-length" title="Content-Length">Section 3.3.2</a> of <a href="#Part1" id="rfc.xref.Part1.2 9"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a></td>2285 <td class="left"><a href="p1-messaging.html#header.content-length" title="Content-Length">Section 3.3.2</a> of <a href="#Part1" id="rfc.xref.Part1.24"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a></td> 2346 2286 </tr> 2347 2287 <tr> … … 2353 2293 </div> 2354 2294 <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a> <a id="payload.body" href="#payload.body">Payload Body</a></h2> 2355 <p id="rfc.section.7.2.p.1">A payload body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1. 30"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. The payload body is obtained from the message body by decoding any <a href="p1-messaging.html#header.transfer-encoding" class="smpl">Transfer-Encoding</a> that might have been applied to ensure safe and proper transfer of the message.2295 <p id="rfc.section.7.2.p.1">A payload body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.25"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. The payload body is obtained from the message body by decoding any <a href="p1-messaging.html#header.transfer-encoding" class="smpl">Transfer-Encoding</a> that might have been applied to ensure safe and proper transfer of the message. 2356 2296 </p> 2357 2297 <div id="rfc.iref.r.1"></div> … … 2372 2312 in an HTTP message, it is referred to as the payload of the message. 2373 2313 </p> 2374 <p id="rfc.section.8.p.4">A representation body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1. 31"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. The representation body is obtained from the message body by decoding any <a href="p1-messaging.html#header.transfer-encoding" class="smpl">Transfer-Encoding</a> that might have been applied to ensure safe and proper transfer of the message.2314 <p id="rfc.section.8.p.4">A representation body is only present in a message when a message body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.26"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. The representation body is obtained from the message body by decoding any <a href="p1-messaging.html#header.transfer-encoding" class="smpl">Transfer-Encoding</a> that might have been applied to ensure safe and proper transfer of the message. 2375 2315 </p> 2376 2316 <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a> <a id="identifying.response.associated.with.representation" href="#identifying.response.associated.with.representation">Identifying the Resource Associated with a Representation</a></h2> 2377 2317 <p id="rfc.section.8.1.p.1">It is sometimes necessary to determine an identifier for the resource associated with a representation.</p> 2378 2318 <p id="rfc.section.8.1.p.2">An HTTP request representation, when present, is always associated with an anonymous (i.e., unidentified) resource.</p> 2379 <p id="rfc.section.8.1.p.3">In the common case, an HTTP response is a representation of the target resource (see <a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1. 32"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). However, this is not always the case. To determine the URI of the resource a response is associated with, the following2319 <p id="rfc.section.8.1.p.3">In the common case, an HTTP response is a representation of the target resource (see <a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.27"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). However, this is not always the case. To determine the URI of the resource a response is associated with, the following 2380 2320 rules are used (with the first applicable one being selected): 2381 2321 </p> … … 2426 2366 <tr> 2427 2367 <td class="left">Content-Type</td> 2428 <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type. 4" title="Content-Type">Section 10.9</a></td>2368 <td class="left"><a href="#header.content-type" id="rfc.xref.header.content-type.3" title="Content-Type">Section 10.9</a></td> 2429 2369 </tr> 2430 2370 <tr> 2431 2371 <td class="left">Expires</td> 2432 <td class="left"><a href="p6-cache.html#header.expires" title="Expires">Section 7.3</a> of <a href="#Part6" id="rfc.xref.Part6.1 7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>2372 <td class="left"><a href="p6-cache.html#header.expires" title="Expires">Section 7.3</a> of <a href="#Part6" id="rfc.xref.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td> 2433 2373 </tr> 2434 2374 </tbody> … … 2469 2409 <p id="rfc.section.8.3.p.2">The data type of the representation data is determined via the header fields <a href="#header.content-type" class="smpl">Content-Type</a> and <a href="#header.content-encoding" class="smpl">Content-Encoding</a>. These define a two-layer, ordered encoding model: 2470 2410 </p> 2471 <div id="rfc.figure.u.2 1"></div><pre class="text"> representation-data := Content-Encoding( Content-Type( bits ) )2411 <div id="rfc.figure.u.20"></div><pre class="text"> representation-data := Content-Encoding( Content-Type( bits ) ) 2472 2412 </pre><p id="rfc.section.8.3.p.4"> <a href="#header.content-type" class="smpl">Content-Type</a> specifies the media type of the underlying data, which defines both the data format and how that data <em class="bcp14">SHOULD</em> be processed by the recipient (within the scope of the request method semantics). Any HTTP/1.1 message containing a payload 2473 2413 body <em class="bcp14">SHOULD</em> include a Content-Type header field defining the media type of the associated representation unless that metadata is unknown … … 2546 2486 </p> 2547 2487 </div> 2548 <p id="rfc.section.9.1.p.7">The <a href="p6-cache.html#header.vary" class="smpl">Vary</a> header field (<a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.1 8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) can be used to express the parameters the server uses to select a representation that is subject to server-driven negotiation.2488 <p id="rfc.section.9.1.p.7">The <a href="p6-cache.html#header.vary" class="smpl">Vary</a> header field (<a href="p6-cache.html#header.vary" title="Vary">Section 7.5</a> of <a href="#Part6" id="rfc.xref.Part6.17"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) can be used to express the parameters the server uses to select a representation that is subject to server-driven negotiation. 2549 2489 </p> 2550 2490 <h2 id="rfc.section.9.2"><a href="#rfc.section.9.2">9.2</a> <a id="agent-driven.negotiation" href="#agent-driven.negotiation">Agent-driven Negotiation</a></h2> … … 2576 2516 a value of 0 means "not acceptable". If no "q" parameter is present, the default weight is 1. 2577 2517 </p> 2578 <div id="rfc.figure.u.2 2"></div><pre class="inline"><span id="rfc.iref.g.31"></span><span id="rfc.iref.g.32"></span> <a href="#quality.values" class="smpl">weight</a> = <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> "q=" <a href="#quality.values" class="smpl">qvalue</a>2518 <div id="rfc.figure.u.21"></div><pre class="inline"><span id="rfc.iref.g.31"></span><span id="rfc.iref.g.32"></span> <a href="#quality.values" class="smpl">weight</a> = <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> "q=" <a href="#quality.values" class="smpl">qvalue</a> 2579 2519 <a href="#quality.values" class="smpl">qvalue</a> = ( "0" [ "." 0*3<a href="#imported.abnf" class="smpl">DIGIT</a> ] ) 2580 2520 / ( "1" [ "." 0*3("0") ] ) … … 2593 2533 for an in-line image. 2594 2534 </p> 2595 <div id="rfc.figure.u.2 3"></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="#header.accept" class="smpl">Accept</a> = #( <a href="#header.accept" class="smpl">media-range</a> [ <a href="#header.accept" class="smpl">accept-params</a> ] )2535 <div id="rfc.figure.u.22"></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="#header.accept" class="smpl">Accept</a> = #( <a href="#header.accept" class="smpl">media-range</a> [ <a href="#header.accept" class="smpl">accept-params</a> ] ) 2596 2536 2597 2537 <a href="#header.accept" class="smpl">media-range</a> = ( "*/*" … … 2614 2554 </div> 2615 2555 <p id="rfc.section.10.1.p.6">The example</p> 2616 <div id="rfc.figure.u.2 4"></div><pre class="text"> Accept: audio/*; q=0.2, audio/basic2556 <div id="rfc.figure.u.23"></div><pre class="text"> Accept: audio/*; q=0.2, audio/basic 2617 2557 </pre><p id="rfc.section.10.1.p.8"> <em class="bcp14">SHOULD</em> be interpreted as "I prefer audio/basic, but send me any audio type if it is the best available after an 80% mark-down in 2618 2558 quality". … … 2623 2563 </p> 2624 2564 <p id="rfc.section.10.1.p.10">A more elaborate example is</p> 2625 <div id="rfc.figure.u.2 5"></div><pre class="text"> Accept: text/plain; q=0.5, text/html,2565 <div id="rfc.figure.u.24"></div><pre class="text"> Accept: text/plain; q=0.5, text/html, 2626 2566 text/x-dvi; q=0.8, text/x-c 2627 2567 </pre><p id="rfc.section.10.1.p.12">Verbally, this would be interpreted as "text/html and text/x-c are the preferred media types, but if they do not exist, then … … 2631 2571 to a given type, the most specific reference has precedence. For example, 2632 2572 </p> 2633 <div id="rfc.figure.u.2 6"></div><pre class="text"> Accept: text/*, text/plain, text/plain;format=flowed, */*2573 <div id="rfc.figure.u.25"></div><pre class="text"> Accept: text/*, text/plain, text/plain;format=flowed, */* 2634 2574 </pre><p id="rfc.section.10.1.p.15">have the following precedence: </p> 2635 2575 <ol> … … 2642 2582 which matches that type. For example, 2643 2583 </p> 2644 <div id="rfc.figure.u.2 7"></div><pre class="text"> Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1,2584 <div id="rfc.figure.u.26"></div><pre class="text"> Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1, 2645 2585 text/html;level=2;q=0.4, */*;q=0.5 2646 2586 </pre><p id="rfc.section.10.1.p.18">would cause the following values to be associated:</p> … … 2691 2631 that capability to a server which is capable of representing documents in those character encodings. 2692 2632 </p> 2693 <div id="rfc.figure.u.2 8"></div><pre class="inline"><span id="rfc.iref.g.37"></span> <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = 1#( ( <a href="#rule.charset" class="smpl">charset</a> / "*" ) [ <a href="#quality.values" class="smpl">weight</a> ] )2633 <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.37"></span> <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = 1#( ( <a href="#rule.charset" class="smpl">charset</a> / "*" ) [ <a href="#quality.values" class="smpl">weight</a> ] ) 2694 2634 </pre><p id="rfc.section.10.2.p.3">Character encoding values (a.k.a., charsets) are described in <a href="#character.sets" title="Character Encodings (charset)">Section 6.3</a>. Each charset <em class="bcp14">MAY</em> be given an associated quality value which represents the user's preference for that charset, as defined in <a href="#quality.values" title="Quality Values">Section 9.3</a>. An example is 2695 2635 </p> 2696 <div id="rfc.figure.u.2 9"></div><pre class="text"> Accept-Charset: iso-8859-5, unicode-1-1;q=0.82636 <div id="rfc.figure.u.28"></div><pre class="text"> Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 2697 2637 </pre><p id="rfc.section.10.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere 2698 2638 in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then any character encodings not explicitly … … 2709 2649 no encoding is preferred. 2710 2650 </p> 2711 <div id="rfc.figure.u. 30"></div><pre class="inline"><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span> <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> = #( <a href="#header.accept-encoding" class="smpl">codings</a> [ <a href="#quality.values" class="smpl">weight</a> ] )2651 <div id="rfc.figure.u.29"></div><pre class="inline"><span id="rfc.iref.g.38"></span><span id="rfc.iref.g.39"></span> <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> = #( <a href="#header.accept-encoding" class="smpl">codings</a> [ <a href="#quality.values" class="smpl">weight</a> ] ) 2712 2652 <a href="#header.accept-encoding" class="smpl">codings</a> = <a href="#content.codings" class="smpl">content-coding</a> / "identity" / "*" 2713 2653 </pre><p id="rfc.section.10.3.p.3">Each codings value <em class="bcp14">MAY</em> be given an associated quality value which represents the preference for that encoding, as defined in <a href="#quality.values" title="Quality Values">Section 9.3</a>. 2714 2654 </p> 2715 2655 <p id="rfc.section.10.3.p.4">For example,</p> 2716 <div id="rfc.figure.u.3 1"></div><pre class="text"> Accept-Encoding: compress, gzip2656 <div id="rfc.figure.u.30"></div><pre class="text"> Accept-Encoding: compress, gzip 2717 2657 Accept-Encoding: 2718 2658 Accept-Encoding: * … … 2750 2690 in the response. Language tags are defined in <a href="#language.tags" title="Language Tags">Section 6.6</a>. 2751 2691 </p> 2752 <div id="rfc.figure.u.3 2"></div><pre class="inline"><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span> <a href="#header.accept-language" class="smpl">Accept-Language</a> = 1#( <a href="#header.accept-language" class="smpl">language-range</a> [ <a href="#quality.values" class="smpl">weight</a> ] )2692 <div id="rfc.figure.u.31"></div><pre class="inline"><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span> <a href="#header.accept-language" class="smpl">Accept-Language</a> = 1#( <a href="#header.accept-language" class="smpl">language-range</a> [ <a href="#quality.values" class="smpl">weight</a> ] ) 2753 2693 <a href="#header.accept-language" class="smpl">language-range</a> = 2754 2694 <language-range, defined in <a href="#RFC4647" id="rfc.xref.RFC4647.1"><cite title="Matching of Language Tags">[RFC4647]</cite></a>, <a href="http://tools.ietf.org/html/rfc4647#section-2.1">Section 2.1</a>> … … 2756 2696 languages specified by that range, as defined in <a href="#quality.values" title="Quality Values">Section 9.3</a>. For example, 2757 2697 </p> 2758 <div id="rfc.figure.u.3 3"></div><pre class="text"> Accept-Language: da, en-gb;q=0.8, en;q=0.72698 <div id="rfc.figure.u.32"></div><pre class="text"> Accept-Language: da, en-gb;q=0.8, en;q=0.7 2759 2699 </pre><p id="rfc.section.10.4.p.5">would mean: "I prefer Danish, but will accept British English and other types of English". (see also <a href="http://tools.ietf.org/html/rfc4647#section-2.3">Section 2.3</a> of <a href="#RFC4647" id="rfc.xref.RFC4647.2"><cite title="Matching of Language Tags">[RFC4647]</cite></a>) 2760 2700 </p> … … 2784 2724 is strictly to inform the recipient of valid request methods associated with the resource. 2785 2725 </p> 2786 <div id="rfc.figure.u.3 4"></div><pre class="inline"><span id="rfc.iref.g.42"></span> <a href="#header.allow" class="smpl">Allow</a> = #<a href="#method.overview" class="smpl">method</a>2726 <div id="rfc.figure.u.33"></div><pre class="inline"><span id="rfc.iref.g.42"></span> <a href="#header.allow" class="smpl">Allow</a> = #<a href="#method.overview" class="smpl">method</a> 2787 2727 </pre><p id="rfc.section.10.5.p.3">Example of use:</p> 2788 <div id="rfc.figure.u.3 5"></div><pre class="text"> Allow: GET, HEAD, PUT2728 <div id="rfc.figure.u.34"></div><pre class="text"> Allow: GET, HEAD, PUT 2789 2729 </pre><p id="rfc.section.10.5.p.5">The actual set of allowed methods is defined by the origin server at the time of each request.</p> 2790 2730 <p id="rfc.section.10.5.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according … … 2798 2738 its underlying media type. 2799 2739 </p> 2800 <div id="rfc.figure.u.3 6"></div><pre class="inline"><span id="rfc.iref.g.43"></span> <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = 1#<a href="#content.codings" class="smpl">content-coding</a>2740 <div id="rfc.figure.u.35"></div><pre class="inline"><span id="rfc.iref.g.43"></span> <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = 1#<a href="#content.codings" class="smpl">content-coding</a> 2801 2741 </pre><p id="rfc.section.10.6.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section 6.4</a>. An example of its use is 2802 2742 </p> 2803 <div id="rfc.figure.u.3 7"></div><pre class="text"> Content-Encoding: gzip2743 <div id="rfc.figure.u.36"></div><pre class="text"> Content-Encoding: gzip 2804 2744 </pre><p id="rfc.section.10.6.p.5">The content-coding is a characteristic of the representation. Typically, the representation body is stored with this encoding 2805 2745 and is only decoded before rendering or analogous usage. However, a transforming proxy <em class="bcp14">MAY</em> modify the content-coding if the new coding is known to be acceptable to the recipient, unless the "no-transform" cache-control … … 2825 2765 that this might not be equivalent to all the languages used within the representation. 2826 2766 </p> 2827 <div id="rfc.figure.u.3 8"></div><pre class="inline"><span id="rfc.iref.g.44"></span> <a href="#header.content-language" class="smpl">Content-Language</a> = 1#<a href="#language.tags" class="smpl">language-tag</a>2767 <div id="rfc.figure.u.37"></div><pre class="inline"><span id="rfc.iref.g.44"></span> <a href="#header.content-language" class="smpl">Content-Language</a> = 1#<a href="#language.tags" class="smpl">language-tag</a> 2828 2768 </pre><p id="rfc.section.10.7.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section 6.6</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate representations according to the 2829 2769 user's own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate 2830 2770 field is 2831 2771 </p> 2832 <div id="rfc.figure.u.3 9"></div><pre class="text"> Content-Language: da2772 <div id="rfc.figure.u.38"></div><pre class="text"> Content-Language: da 2833 2773 </pre><p id="rfc.section.10.7.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean 2834 2774 that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language … … 2838 2778 simultaneously in the original Maori and English versions, would call for 2839 2779 </p> 2840 <div id="rfc.figure.u. 40"></div><pre class="text"> Content-Language: mi, en2780 <div id="rfc.figure.u.39"></div><pre class="text"> Content-Language: mi, en 2841 2781 </pre><p id="rfc.section.10.7.p.8">However, just because multiple languages are present within a representation does not mean that it is intended for multiple 2842 2782 linguistic audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin", which is clearly … … 2851 2791 message. In other words, if one were to perform a GET on this URI at the time of this message's generation, then a <a href="#status.200" class="smpl">200 (OK)</a> response would contain the same representation that is enclosed as payload in this message. 2852 2792 </p> 2853 <div id="rfc.figure.u.4 1"></div><pre class="inline"><span id="rfc.iref.g.45"></span> <a href="#header.content-location" class="smpl">Content-Location</a> = <a href="#imported.abnf" class="smpl">absolute-URI</a> / <a href="#imported.abnf" class="smpl">partial-URI</a>2854 </pre><p id="rfc.section.10.8.p.3">The Content-Location value is not a replacement for the effective Request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1. 33"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). It is representation metadata. It has the same syntax and semantics as the header field of the same name defined for MIME2793 <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.45"></span> <a href="#header.content-location" class="smpl">Content-Location</a> = <a href="#imported.abnf" class="smpl">absolute-URI</a> / <a href="#imported.abnf" class="smpl">partial-URI</a> 2794 </pre><p id="rfc.section.10.8.p.3">The Content-Location value is not a replacement for the effective Request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.28"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). It is representation metadata. It has the same syntax and semantics as the header field of the same name defined for MIME 2855 2795 body parts in <a href="http://tools.ietf.org/html/rfc2557#section-4">Section 4</a> of <a href="#RFC2557" id="rfc.xref.RFC2557.1"><cite title="MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)">[RFC2557]</cite></a>. However, its appearance in an HTTP message has some special implications for HTTP recipients. 2856 2796 </p> … … 2891 2831 the media type is that which would have been sent had the request been a GET. 2892 2832 </p> 2893 <div id="rfc.figure.u.4 2"></div><pre class="inline"><span id="rfc.iref.g.46"></span> <a href="#header.content-type" class="smpl">Content-Type</a> = <a href="#media.types" class="smpl">media-type</a>2833 <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.46"></span> <a href="#header.content-type" class="smpl">Content-Type</a> = <a href="#media.types" class="smpl">media-type</a> 2894 2834 </pre><p id="rfc.section.10.9.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section 6.5</a>. An example of the field is 2895 2835 </p> 2896 <div id="rfc.figure.u.4 3"></div><pre class="text"> Content-Type: text/html; charset=ISO-8859-42836 <div id="rfc.figure.u.42"></div><pre class="text"> Content-Type: text/html; charset=ISO-8859-4 2897 2837 </pre><p id="rfc.section.10.9.p.5">Further discussion of Content-Type is provided in <a href="#representation.data" title="Representation Data">Section 8.3</a>. 2898 2838 </p> … … 2903 2843 Origination Date Field (orig-date) defined in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.1">Section 3.6.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as defined in <a href="#http.date" title="Date/Time Formats">Section 6.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format. 2904 2844 </p> 2905 <div id="rfc.figure.u.4 4"></div><pre class="inline"><span id="rfc.iref.g.47"></span> <a href="#header.date" class="smpl">Date</a> = <a href="#http.date" class="smpl">HTTP-date</a>2845 <div id="rfc.figure.u.43"></div><pre class="inline"><span id="rfc.iref.g.47"></span> <a href="#header.date" class="smpl">Date</a> = <a href="#http.date" class="smpl">HTTP-date</a> 2906 2846 </pre><p id="rfc.section.10.10.p.3">An example is</p> 2907 <div id="rfc.figure.u.4 5"></div><pre class="text"> Date: Tue, 15 Nov 1994 08:12:31 GMT2847 <div id="rfc.figure.u.44"></div><pre class="text"> Date: Tue, 15 Nov 1994 08:12:31 GMT 2908 2848 </pre><p id="rfc.section.10.10.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases: 2909 2849 </p> … … 2931 2871 <h2 id="rfc.section.10.11"><a href="#rfc.section.10.11">10.11</a> <a id="header.expect" href="#header.expect">Expect</a></h2> 2932 2872 <p id="rfc.section.10.11.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p> 2933 <div id="rfc.figure.u.4 6"></div><pre class="inline"><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span><span id="rfc.iref.g.50"></span><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span> <a href="#header.expect" class="smpl">Expect</a> = 1#<a href="#header.expect" class="smpl">expectation</a>2873 <div id="rfc.figure.u.45"></div><pre class="inline"><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span><span id="rfc.iref.g.50"></span><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span> <a href="#header.expect" class="smpl">Expect</a> = 1#<a href="#header.expect" class="smpl">expectation</a> 2934 2874 2935 2875 <a href="#header.expect" class="smpl">expectation</a> = <a href="#header.expect" class="smpl">expect-name</a> [ <a href="#imported.abnf" class="smpl">BWS</a> "=" <a href="#imported.abnf" class="smpl">BWS</a> <a href="#header.expect" class="smpl">expect-value</a> ] … … 2946 2886 </p> 2947 2887 <ul class="empty"> 2948 <li>The "100-continue" expectation is defined <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1. 34"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. It does not support any expect-params.2888 <li>The "100-continue" expectation is defined <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.29"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>. It does not support any expect-params. 2949 2889 </li> 2950 2890 </ul> … … 2959 2899 <p id="rfc.section.10.12.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>: 2960 2900 </p> 2961 <div id="rfc.figure.u.4 7"></div><pre class="inline"><span id="rfc.iref.g.53"></span> <a href="#header.from" class="smpl">From</a> = <a href="#header.from" class="smpl">mailbox</a>2901 <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.53"></span> <a href="#header.from" class="smpl">From</a> = <a href="#header.from" class="smpl">mailbox</a> 2962 2902 2963 2903 <a href="#header.from" class="smpl">mailbox</a> = <mailbox, defined in <a href="#RFC5322" id="rfc.xref.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a>> 2964 2904 </pre><p id="rfc.section.10.12.p.3">An example is:</p> 2965 <div id="rfc.figure.u.4 8"></div><pre class="text"> From: webmaster@example.org2905 <div id="rfc.figure.u.47"></div><pre class="text"> From: webmaster@example.org 2966 2906 </pre><p id="rfc.section.10.12.p.5">This header field <em class="bcp14">MAY</em> be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It <em class="bcp14">SHOULD NOT</em> be used as an insecure form of access protection. The interpretation of this field is that the request is being performed 2967 2907 on behalf of the person given, who accepts responsibility for the method performed. In particular, robot agents <em class="bcp14">SHOULD</em> include this header field so that the person responsible for running the robot can be contacted if problems occur on the receiving … … 2980 2920 <p id="rfc.section.10.13.p.1">The "Location" header field <em class="bcp14">MAY</em> be sent in responses to refer to a specific resource in accordance with the semantics of the status code. 2981 2921 </p> 2982 <div id="rfc.figure.u.4 9"></div><pre class="inline"><span id="rfc.iref.g.54"></span> <a href="#header.location" class="smpl">Location</a> = <a href="#imported.abnf" class="smpl">URI-reference</a>2922 <div id="rfc.figure.u.48"></div><pre class="inline"><span id="rfc.iref.g.54"></span> <a href="#header.location" class="smpl">Location</a> = <a href="#imported.abnf" class="smpl">URI-reference</a> 2983 2923 </pre><p id="rfc.section.10.13.p.3">For <a href="#status.201" class="smpl">201 (Created)</a> responses, the Location is the URI of the new resource which was created by the request. For <a href="#status.3xx" class="smpl">3xx (Redirection)</a> responses, the location <em class="bcp14">SHOULD</em> indicate the server's preferred URI for automatic redirection to the resource. 2984 2924 </p> … … 2986 2926 then the original URI's fragment identifier is added to the final value. 2987 2927 </p> 2988 <div id="rfc.figure.u. 50"></div>2928 <div id="rfc.figure.u.49"></div> 2989 2929 <p>For example, the original URI "http://www.example.org/~tim", combined with a field value given as:</p> <pre class="text"> Location: /pub/WWW/People.html#tim 2990 2930 </pre> <p>would result in a final value of "http://www.example.org/pub/WWW/People.html#tim"</p> 2991 <div id="rfc.figure.u.5 1"></div>2931 <div id="rfc.figure.u.50"></div> 2992 2932 <p>An original URI "http://www.example.org/index.html#larry", combined with a field value given as:</p> <pre class="text"> Location: http://www.example.net/index.html 2993 2933 </pre> <p>would result in a final value of "http://www.example.net/index.html#larry", preserving the original fragment identifier.</p> … … 3012 2952 to trace a request which appears to be failing or looping mid-chain. 3013 2953 </p> 3014 <div id="rfc.figure.u.5 2"></div><pre class="inline"><span id="rfc.iref.g.55"></span> <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#imported.abnf" class="smpl">DIGIT</a>2954 <div id="rfc.figure.u.51"></div><pre class="inline"><span id="rfc.iref.g.55"></span> <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#imported.abnf" class="smpl">DIGIT</a> 3015 2955 </pre><p id="rfc.section.10.14.p.3">The Max-Forwards value is a decimal integer indicating the remaining number of times this request message can be forwarded.</p> 3016 2956 <p id="rfc.section.10.14.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1). … … 3032 2972 non-HTTP URIs (e.g., FTP). 3033 2973 </p> 3034 <div id="rfc.figure.u.5 3"></div><pre class="inline"><span id="rfc.iref.g.56"></span> <a href="#header.referer" class="smpl">Referer</a> = <a href="#imported.abnf" class="smpl">absolute-URI</a> / <a href="#imported.abnf" class="smpl">partial-URI</a>2974 <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.56"></span> <a href="#header.referer" class="smpl">Referer</a> = <a href="#imported.abnf" class="smpl">absolute-URI</a> / <a href="#imported.abnf" class="smpl">partial-URI</a> 3035 2975 </pre><p id="rfc.section.10.15.p.5">Example:</p> 3036 <div id="rfc.figure.u.5 4"></div><pre class="text"> Referer: http://www.example.org/hypertext/Overview.html2976 <div id="rfc.figure.u.53"></div><pre class="text"> Referer: http://www.example.org/hypertext/Overview.html 3037 2977 </pre><p id="rfc.section.10.15.p.7">If the field value is a relative URI, it <em class="bcp14">SHOULD</em> be interpreted relative to the effective request URI. The URI <em class="bcp14">MUST NOT</em> include a fragment. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section 12.2</a> for security considerations. 3038 2978 </p> … … 3044 2984 </p> 3045 2985 <p id="rfc.section.10.16.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p> 3046 <div id="rfc.figure.u.5 5"></div><pre class="inline"><span id="rfc.iref.g.57"></span> <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#http.date" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>2986 <div id="rfc.figure.u.54"></div><pre class="inline"><span id="rfc.iref.g.57"></span> <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#http.date" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a> 3047 2987 </pre><div id="rule.delta-seconds"> 3048 2988 <p id="rfc.section.10.16.p.4"> Time spans are non-negative decimal integers, representing time in seconds.</p> 3049 2989 </div> 3050 <div id="rfc.figure.u.5 6"></div><pre class="inline"><span id="rfc.iref.g.58"></span> <a href="#rule.delta-seconds" class="smpl">delta-seconds</a> = 1*<a href="#imported.abnf" class="smpl">DIGIT</a>2990 <div id="rfc.figure.u.55"></div><pre class="inline"><span id="rfc.iref.g.58"></span> <a href="#rule.delta-seconds" class="smpl">delta-seconds</a> = 1*<a href="#imported.abnf" class="smpl">DIGIT</a> 3051 2991 </pre><p id="rfc.section.10.16.p.6">Two examples of its use are</p> 3052 <div id="rfc.figure.u.5 7"></div><pre class="text"> Retry-After: Fri, 31 Dec 1999 23:59:59 GMT2992 <div id="rfc.figure.u.56"></div><pre class="text"> Retry-After: Fri, 31 Dec 1999 23:59:59 GMT 3053 2993 Retry-After: 120 3054 2994 </pre><p id="rfc.section.10.16.p.8">In the latter example, the delay is 2 minutes.</p> … … 3057 2997 <h2 id="rfc.section.10.17"><a href="#rfc.section.10.17">10.17</a> <a id="header.server" href="#header.server">Server</a></h2> 3058 2998 <p id="rfc.section.10.17.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p> 3059 <p id="rfc.section.10.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section 6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.3 5"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for2999 <p id="rfc.section.10.17.p.2">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section 6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.30"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for 3060 3000 identifying the application. 3061 3001 </p> 3062 <div id="rfc.figure.u.5 8"></div><pre class="inline"><span id="rfc.iref.g.59"></span> <a href="#header.server" class="smpl">Server</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#imported.abnf" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#imported.abnf" class="smpl">comment</a> ) )3002 <div id="rfc.figure.u.57"></div><pre class="inline"><span id="rfc.iref.g.59"></span> <a href="#header.server" class="smpl">Server</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#imported.abnf" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#imported.abnf" class="smpl">comment</a> ) ) 3063 3003 </pre><p id="rfc.section.10.17.p.4">Example:</p> 3064 <div id="rfc.figure.u.5 9"></div><pre class="text"> Server: CERN/3.0 libwww/2.173065 </pre><p id="rfc.section.10.17.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the <a href="#header.server" class="smpl">Server</a> header field. Instead, it <em class="bcp14">MUST</em> include a <a href="p1-messaging.html#header.via" class="smpl">Via</a> field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 5.7</a> of <a href="#Part1" id="rfc.xref.Part1.3 6"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>).3004 <div id="rfc.figure.u.58"></div><pre class="text"> Server: CERN/3.0 libwww/2.17 3005 </pre><p id="rfc.section.10.17.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the <a href="#header.server" class="smpl">Server</a> header field. Instead, it <em class="bcp14">MUST</em> include a <a href="p1-messaging.html#header.via" class="smpl">Via</a> field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 5.7</a> of <a href="#Part1" id="rfc.xref.Part1.31"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 3066 3006 </p> 3067 3007 <div class="note" id="rfc.section.10.17.p.7"> … … 3079 3019 user agent limitations. 3080 3020 </p> 3081 <p id="rfc.section.10.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section 6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.3 7"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance3021 <p id="rfc.section.10.18.p.3">The field can contain multiple product tokens (<a href="#product.tokens" title="Product Tokens">Section 6.2</a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.32"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance 3082 3022 for identifying the application. 3083 3023 </p> … … 3090 3030 doing so makes the field value more difficult to parse. 3091 3031 </p> 3092 <div id="rfc.figure.u. 60"></div><pre class="inline"><span id="rfc.iref.g.60"></span> <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#imported.abnf" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#imported.abnf" class="smpl">comment</a> ) )3032 <div id="rfc.figure.u.59"></div><pre class="inline"><span id="rfc.iref.g.60"></span> <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#product.tokens" class="smpl">product</a> *( <a href="#imported.abnf" class="smpl">RWS</a> ( <a href="#product.tokens" class="smpl">product</a> / <a href="#imported.abnf" class="smpl">comment</a> ) ) 3093 3033 </pre><p id="rfc.section.10.18.p.7">Example:</p> 3094 <div id="rfc.figure.u.6 1"></div><pre class="text"> User-Agent: CERN-LineMode/2.15 libwww/2.17b33034 <div id="rfc.figure.u.60"></div><pre class="text"> User-Agent: CERN-LineMode/2.15 libwww/2.17b3 3095 3035 </pre><h1 id="rfc.section.11"><a href="#rfc.section.11">11.</a> <a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1> 3096 3036 <h2 id="rfc.section.11.1"><a href="#rfc.section.11.1">11.1</a> <a id="method.registry" href="#method.registry">Method Registry</a></h2> … … 3116 3056 specific to a single application or data format, since orthogonal technologies deserve orthogonal specification. 3117 3057 </p> 3118 <p id="rfc.section.11.1.2.p.2">Since HTTP message parsing (<a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.3 8"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) is independent of method semantics (aside from responses to HEAD), definitions of new HTTP methods cannot change the parsing3058 <p id="rfc.section.11.1.2.p.2">Since HTTP message parsing (<a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.33"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>) is independent of method semantics (aside from responses to HEAD), definitions of new HTTP methods cannot change the parsing 3119 3059 algorithm or prohibit the presence of a message body on either the request or the response message. Definitions of new methods 3120 3060 can specify that only zero-length bodies are allowed, which would imply that each such messages would be required to contain … … 3221 3161 a zero-length response body. They can require the presence of one or more particular HTTP response header field(s). 3222 3162 </p> 3223 <p id="rfc.section.11.2.2.p.5">Likewise, their definitions can specify that caches are allowed to use heuristics to determine their freshness (see <a href="#Part6" id="rfc.xref.Part6.1 9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>; by default, it is not allowed), and can define how to determine the resource which they carry a representation for (see <a href="#identifying.response.associated.with.representation" title="Identifying the Resource Associated with a Representation">Section 8.1</a>; by default, it is anonymous).3163 <p id="rfc.section.11.2.2.p.5">Likewise, their definitions can specify that caches are allowed to use heuristics to determine their freshness (see <a href="#Part6" id="rfc.xref.Part6.18"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>; by default, it is not allowed), and can define how to determine the resource which they carry a representation for (see <a href="#identifying.response.associated.with.representation" title="Identifying the Resource Associated with a Representation">Section 8.1</a>; by default, it is anonymous). 3224 3164 </p> 3225 3165 <h3 id="rfc.section.11.2.3"><a href="#rfc.section.11.2.3">11.2.3</a> <a id="status.code.registration" href="#status.code.registration">Registrations</a></h3> … … 3455 3395 </table> 3456 3396 </div> 3457 <h2 id="rfc.section.11.3"><a href="#rfc.section.11.3">11.3</a> <a id="header.field.registration" href="#header.field.registration">Header Field Registration</a></h2> 3458 <p id="rfc.section.11.3.p.1">HTTP header fields are registered within the Message Header Field Registry located at <<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>> (see <a href="#RFC3864" id="rfc.xref.RFC3864.3"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>). The Message Header Field Registry shall be updated with the permanent registrations below: 3459 </p> 3397 <h2 id="rfc.section.11.3"><a href="#rfc.section.11.3">11.3</a> <a id="header.field.registry" href="#header.field.registry">Header Field Registry</a></h2> 3398 <p id="rfc.section.11.3.p.1">HTTP header fields are registered within the Message Header Field Registry located at <<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>>, as defined by <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>. 3399 </p> 3400 <h3 id="rfc.section.11.3.1"><a href="#rfc.section.11.3.1">11.3.1</a> <a id="considerations.for.new.header.fields" href="#considerations.for.new.header.fields">Considerations for New Header Fields</a></h3> 3401 <p id="rfc.section.11.3.1.p.1">The requirements for header field names are defined in <a href="http://tools.ietf.org/html/rfc3864#section-4.1">Section 4.1</a> of <a href="#RFC3864" id="rfc.xref.RFC3864.2"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>. Authors of specifications defining new fields are advised to keep the name as short as practical, and not to prefix them 3402 with "X-" if they are to be registered (either immediately or in the future). 3403 </p> 3404 <p id="rfc.section.11.3.1.p.2">New header field values typically have their syntax defined using ABNF (<a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>), using the extension defined in <a href="p1-messaging.html#abnf.extension" title="ABNF list extension: #rule">Appendix B</a> of <a href="#Part1" id="rfc.xref.Part1.34"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a> as necessary, and are usually constrained to the range of ASCII characters. Header fields needing a greater range of characters 3405 can use an encoding such as the one defined in <a href="#RFC5987" id="rfc.xref.RFC5987.1"><cite title="Character Set and Language Encoding for Hypertext Transfer Protocol (HTTP) Header Field Parameters">[RFC5987]</cite></a>. 3406 </p> 3407 <p id="rfc.section.11.3.1.p.3">Because commas (",") are used as a generic delimiter between field-values, they need to be treated with care if they are allowed 3408 in the field-value's payload. Typically, components that might contain a comma are protected with double-quotes using the 3409 quoted-string ABNF production (<a href="p1-messaging.html#field.components" title="Field value components">Section 3.2.4</a> of <a href="#Part1" id="rfc.xref.Part1.35"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 3410 </p> 3411 <p id="rfc.section.11.3.1.p.4">For example, a textual date and a URI (either of which might contain a comma) could be safely carried in field-values like 3412 these: 3413 </p> 3414 <div id="rfc.figure.u.61"></div><pre class="text"> Example-URI-Field: "http://example.com/a.html,foo", 3415 "http://without-a-comma.example.com/" 3416 Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005" 3417 </pre><p id="rfc.section.11.3.1.p.6">Note that double-quote delimiters almost always are used with the quoted-string production; using a different syntax inside 3418 double-quotes will likely cause unnecessary confusion. 3419 </p> 3420 <p id="rfc.section.11.3.1.p.7">Many header fields use a format including (case-insensitively) named parameters (for instance, <a href="#header.content-type" class="smpl">Content-Type</a>, defined in <a href="#header.content-type" id="rfc.xref.header.content-type.4" title="Content-Type">Section 10.9</a>). Allowing both unquoted (token) and quoted (quoted-string) syntax for the parameter value enables recipients to use existing 3421 parser components. When allowing both forms, the meaning of a parameter value ought to be independent of the syntax used for 3422 it (for an example, see the notes on parameter handling for media types in <a href="#media.types" title="Media Types">Section 6.5</a>). 3423 </p> 3424 <p id="rfc.section.11.3.1.p.8">Authors of specifications defining new header fields are advised to consider documenting: </p> 3425 <ul> 3426 <li> 3427 <p>Whether the field is a single value, or whether it can be a list (delimited by commas; see <a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.36"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 3428 </p> 3429 <p>If it does not use the list syntax, document how to treat messages where the header field occurs multiple times (a sensible 3430 default would be to ignore the header field, but this might not always be the right choice). 3431 </p> 3432 <p>Note that intermediaries and software libraries might combine multiple header field instances into a single one, despite the 3433 header field not allowing this. A robust format enables recipients to discover these situations (good example: "Content-Type", 3434 as the comma can only appear inside quoted strings; bad example: "Location", as a comma can occur inside a URI). 3435 </p> 3436 </li> 3437 <li> 3438 <p>Under what conditions the header field can be used; e.g., only in responses or requests, in all messages, only on responses 3439 to a particular request method. 3440 </p> 3441 </li> 3442 <li> 3443 <p>Whether it is appropriate to list the field-name in the <a href="p1-messaging.html#header.connection" class="smpl">Connection</a> header field (i.e., if the header field is to be hop-by-hop, see <a href="p1-messaging.html#header.connection" title="Connection">Section 6.1</a> of <a href="#Part1" id="rfc.xref.Part1.37"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 3444 </p> 3445 </li> 3446 <li> 3447 <p>Under what conditions intermediaries are allowed to modify the header field's value, insert or delete it.</p> 3448 </li> 3449 <li> 3450 <p>How the header field might interact with caching (see <a href="#Part6" id="rfc.xref.Part6.19"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). 3451 </p> 3452 </li> 3453 <li> 3454 <p>Whether the header field is useful or allowable in trailers (see <a href="p1-messaging.html#chunked.encoding" title="Chunked Transfer Coding">Section 4.1</a> of <a href="#Part1" id="rfc.xref.Part1.38"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). 3455 </p> 3456 </li> 3457 <li> 3458 <p>Whether the header field ought to be preserved across redirects.</p> 3459 </li> 3460 </ul> 3461 <h3 id="rfc.section.11.3.2"><a href="#rfc.section.11.3.2">11.3.2</a> <a id="header.field.registration" href="#header.field.registration">Registrations</a></h3> 3462 <p id="rfc.section.11.3.2.p.1">The Message Header Field Registry shall be updated with the following permanent registrations:</p> 3460 3463 <div id="rfc.table.4"> 3461 3464 <div id="iana.header.registration.table"></div> … … 3606 3609 </table> 3607 3610 </div> 3608 <p id="rfc.section.11.3. p.2">The change controller for the above registrations is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>3611 <p id="rfc.section.11.3.2.p.2">The change controller for the above registrations is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p> 3609 3612 <h2 id="rfc.section.11.4"><a href="#rfc.section.11.4">11.4</a> <a id="content.coding.registry" href="#content.coding.registry">Content Coding Registry</a></h2> 3610 3613 <p id="rfc.section.11.4.p.1">The HTTP Content Coding Registry defines the name space for content coding names (<a href="p1-messaging.html#compression.codings" title="Compression Codings">Section 4.2</a> of <a href="#Part1" id="rfc.xref.Part1.39"><cite title="HTTP/1.1, part 1: Message Routing and Syntax"">[Part1]</cite></a>). The content coding registry is maintained at <<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>>. … … 4859 4862 </li> 4860 4863 <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul> 4861 <li>Accept header field <a href="#rfc.xref.header.accept.1">4. 6</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.a.1"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3</a></li>4862 <li>Accept-Charset header field <a href="#rfc.xref.header.accept-charset.1">4. 6</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</a>, <a href="#rfc.iref.a.2"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>4863 <li>Accept-Encoding header field <a href="#rfc.xref.header.accept-encoding.1">4. 6</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</a>, <a href="#rfc.iref.a.3"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li>4864 <li>Accept-Language header field <a href="#rfc.xref.header.accept-language.1">4. 6</a>, <a href="#rfc.xref.header.accept-language.2">9.1</a>, <a href="#rfc.iref.a.4"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3</a></li>4865 <li>Allow header field <a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4. 7</a>, <a href="#rfc.iref.a.5"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3</a>, <a href="#rfc.xref.header.allow.4">C</a></li>4864 <li>Accept header field <a href="#rfc.xref.header.accept.1">4.5</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.a.1"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3.2</a></li> 4865 <li>Accept-Charset header field <a href="#rfc.xref.header.accept-charset.1">4.5</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</a>, <a href="#rfc.iref.a.2"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3.2</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li> 4866 <li>Accept-Encoding header field <a href="#rfc.xref.header.accept-encoding.1">4.5</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</a>, <a href="#rfc.iref.a.3"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3.2</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li> 4867 <li>Accept-Language header field <a href="#rfc.xref.header.accept-language.1">4.5</a>, <a href="#rfc.xref.header.accept-language.2">9.1</a>, <a href="#rfc.iref.a.4"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3.2</a></li> 4868 <li>Allow header field <a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4.6</a>, <a href="#rfc.iref.a.5"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3.2</a>, <a href="#rfc.xref.header.allow.4">C</a></li> 4866 4869 </ul> 4867 4870 </li> … … 4878 4881 <li>CONNECT method <a href="#rfc.xref.CONNECT.1">3.1</a>, <a href="#rfc.iref.c.3"><b>3.3.8</b></a>, <a href="#rfc.xref.CONNECT.2">11.1.3</a>, <a href="#rfc.xref.CONNECT.3">C</a></li> 4879 4882 <li>content negotiation <a href="#rfc.iref.c.1">1</a></li> 4880 <li>Content-Encoding header field <a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</a>, <a href="#rfc.iref.c.8"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3 </a></li>4881 <li>Content-Language header field <a href="#rfc.xref.header.content-language.1">8.2</a>, <a href="#rfc.iref.c.9"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3 </a></li>4882 <li>Content-Location header field <a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</a>, <a href="#rfc.iref.c.10"><b>10.8</b></a>, <a href="#rfc.xref.header.content-location.3">10.13</a>, <a href="#rfc.xref.header.content-location.4">11.3 </a>, <a href="#rfc.xref.header.content-location.5">C</a></li>4883 <li>Content-Encoding header field <a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</a>, <a href="#rfc.iref.c.8"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3.2</a></li> 4884 <li>Content-Language header field <a href="#rfc.xref.header.content-language.1">8.2</a>, <a href="#rfc.iref.c.9"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3.2</a></li> 4885 <li>Content-Location header field <a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</a>, <a href="#rfc.iref.c.10"><b>10.8</b></a>, <a href="#rfc.xref.header.content-location.3">10.13</a>, <a href="#rfc.xref.header.content-location.4">11.3.2</a>, <a href="#rfc.xref.header.content-location.5">C</a></li> 4883 4886 <li>Content-Transfer-Encoding header field <a href="#rfc.iref.c.12">A.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">C</a></li> 4884 <li>Content-Type header field <a href="#rfc.xref.header.content-type.1"> 4.5</a>, <a href="#rfc.xref.header.content-type.2">5</a>, <a href="#rfc.xref.header.content-type.3">6.5</a>, <a href="#rfc.xref.header.content-type.4">8.2</a>, <a href="#rfc.iref.c.11"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.5">11.3</a></li>4887 <li>Content-Type header field <a href="#rfc.xref.header.content-type.1">5</a>, <a href="#rfc.xref.header.content-type.2">6.5</a>, <a href="#rfc.xref.header.content-type.3">8.2</a>, <a href="#rfc.iref.c.11"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.4">11.3.1</a>, <a href="#rfc.xref.header.content-type.5">11.3.2</a></li> 4885 4888 </ul> 4886 4889 </li> 4887 4890 <li><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul> 4888 <li>Date header field <a href="#rfc.xref.header.date.1">4. 7</a>, <a href="#rfc.iref.d.3"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3</a></li>4891 <li>Date header field <a href="#rfc.xref.header.date.1">4.6</a>, <a href="#rfc.iref.d.3"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3.2</a></li> 4889 4892 <li>deflate (Coding Format) <a href="#rfc.iref.d.2">6.4</a></li> 4890 4893 <li>DELETE method <a href="#rfc.xref.DELETE.1">3.1</a>, <a href="#rfc.iref.d.1"><b>3.3.6</b></a>, <a href="#rfc.xref.DELETE.2">11.1.3</a></li> … … 4892 4895 </li> 4893 4896 <li><a id="rfc.index.E" href="#rfc.index.E"><b>E</b></a><ul> 4894 <li>Expect header field <a href="#rfc.xref.header.expect.1">4. 6</a>, <a href="#rfc.xref.header.expect.2">5.5.14</a>, <a href="#rfc.iref.e.1"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3</a>, <a href="#rfc.xref.header.expect.4">C</a></li>4897 <li>Expect header field <a href="#rfc.xref.header.expect.1">4.5</a>, <a href="#rfc.xref.header.expect.2">5.5.14</a>, <a href="#rfc.iref.e.1"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3.2</a>, <a href="#rfc.xref.header.expect.4">C</a></li> 4895 4898 <li>Expect Values 4896 4899 <ul> … … 4901 4904 </li> 4902 4905 <li><a id="rfc.index.F" href="#rfc.index.F"><b>F</b></a><ul> 4903 <li>From header field <a href="#rfc.xref.header.from.1">4. 6</a>, <a href="#rfc.iref.f.1"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3</a></li>4906 <li>From header field <a href="#rfc.xref.header.from.1">4.5</a>, <a href="#rfc.iref.f.1"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3.2</a></li> 4904 4907 </ul> 4905 4908 </li> … … 4976 4979 <li>Header Fields 4977 4980 <ul> 4978 <li>Accept <a href="#rfc.xref.header.accept.1">4. 6</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.h.2"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3</a></li>4979 <li>Accept-Charset <a href="#rfc.xref.header.accept-charset.1">4. 6</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</a>, <a href="#rfc.iref.h.3"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li>4980 <li>Accept-Encoding <a href="#rfc.xref.header.accept-encoding.1">4. 6</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</a>, <a href="#rfc.iref.h.4"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li>4981 <li>Accept-Language <a href="#rfc.xref.header.accept-language.1">4. 6</a>, <a href="#rfc.xref.header.accept-language.2">9.1</a>, <a href="#rfc.iref.h.5"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3</a></li>4982 <li>Allow <a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4. 7</a>, <a href="#rfc.iref.h.6"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3</a>, <a href="#rfc.xref.header.allow.4">C</a></li>4983 <li>Content-Encoding <a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</a>, <a href="#rfc.iref.h.7"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3 </a></li>4984 <li>Content-Language <a href="#rfc.xref.header.content-language.1">8.2</a>, <a href="#rfc.iref.h.8"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3 </a></li>4985 <li>Content-Location <a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</a>, <a href="#rfc.iref.h.9"><b>10.8</b></a>, <a href="#rfc.xref.header.content-location.3">10.13</a>, <a href="#rfc.xref.header.content-location.4">11.3 </a>, <a href="#rfc.xref.header.content-location.5">C</a></li>4981 <li>Accept <a href="#rfc.xref.header.accept.1">4.5</a>, <a href="#rfc.xref.header.accept.2">6.5</a>, <a href="#rfc.xref.header.accept.3">9.1</a>, <a href="#rfc.iref.h.2"><b>10.1</b></a>, <a href="#rfc.xref.header.accept.4">11.3.2</a></li> 4982 <li>Accept-Charset <a href="#rfc.xref.header.accept-charset.1">4.5</a>, <a href="#rfc.xref.header.accept-charset.2">9.1</a>, <a href="#rfc.iref.h.3"><b>10.2</b></a>, <a href="#rfc.xref.header.accept-charset.3">11.3.2</a>, <a href="#rfc.xref.header.accept-charset.4">C</a></li> 4983 <li>Accept-Encoding <a href="#rfc.xref.header.accept-encoding.1">4.5</a>, <a href="#rfc.xref.header.accept-encoding.2">6.4</a>, <a href="#rfc.xref.header.accept-encoding.3">9.1</a>, <a href="#rfc.iref.h.4"><b>10.3</b></a>, <a href="#rfc.xref.header.accept-encoding.4">11.3.2</a>, <a href="#rfc.xref.header.accept-encoding.5">11.4.2</a></li> 4984 <li>Accept-Language <a href="#rfc.xref.header.accept-language.1">4.5</a>, <a href="#rfc.xref.header.accept-language.2">9.1</a>, <a href="#rfc.iref.h.5"><b>10.4</b></a>, <a href="#rfc.xref.header.accept-language.3">11.3.2</a></li> 4985 <li>Allow <a href="#rfc.xref.header.allow.1">3.1</a>, <a href="#rfc.xref.header.allow.2">4.6</a>, <a href="#rfc.iref.h.6"><b>10.5</b></a>, <a href="#rfc.xref.header.allow.3">11.3.2</a>, <a href="#rfc.xref.header.allow.4">C</a></li> 4986 <li>Content-Encoding <a href="#rfc.xref.header.content-encoding.1">6.4</a>, <a href="#rfc.xref.header.content-encoding.2">8.2</a>, <a href="#rfc.iref.h.7"><b>10.6</b></a>, <a href="#rfc.xref.header.content-encoding.3">11.3.2</a></li> 4987 <li>Content-Language <a href="#rfc.xref.header.content-language.1">8.2</a>, <a href="#rfc.iref.h.8"><b>10.7</b></a>, <a href="#rfc.xref.header.content-language.2">11.3.2</a></li> 4988 <li>Content-Location <a href="#rfc.xref.header.content-location.1">3.3.4</a>, <a href="#rfc.xref.header.content-location.2">8.2</a>, <a href="#rfc.iref.h.9"><b>10.8</b></a>, <a href="#rfc.xref.header.content-location.3">10.13</a>, <a href="#rfc.xref.header.content-location.4">11.3.2</a>, <a href="#rfc.xref.header.content-location.5">C</a></li> 4986 4989 <li>Content-Transfer-Encoding <a href="#rfc.iref.h.21">A.5</a>, <a href="#rfc.xref.no.content-transfer-encoding.1">C</a></li> 4987 <li>Content-Type <a href="#rfc.xref.header.content-type.1"> 4.5</a>, <a href="#rfc.xref.header.content-type.2">5</a>, <a href="#rfc.xref.header.content-type.3">6.5</a>, <a href="#rfc.xref.header.content-type.4">8.2</a>, <a href="#rfc.iref.h.10"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.5">11.3</a></li>4988 <li>Date <a href="#rfc.xref.header.date.1">4. 7</a>, <a href="#rfc.iref.h.11"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3</a></li>4989 <li>Expect <a href="#rfc.xref.header.expect.1">4. 6</a>, <a href="#rfc.xref.header.expect.2">5.5.14</a>, <a href="#rfc.iref.h.12"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3</a>, <a href="#rfc.xref.header.expect.4">C</a></li>4990 <li>From <a href="#rfc.xref.header.from.1">4. 6</a>, <a href="#rfc.iref.h.13"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3</a></li>4991 <li>Location <a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4. 7</a>, <a href="#rfc.xref.header.location.3">5.4</a>, <a href="#rfc.iref.h.14"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3</a>, <a href="#rfc.xref.header.location.5">C</a></li>4992 <li>Max-Forwards <a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4. 6</a>, <a href="#rfc.iref.h.15"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>4993 <li>MIME-Version <a href="#rfc.xref.mime-version.1">11.3 </a>, <a href="#rfc.iref.h.20"><b>A.1</b></a></li>4994 <li>Referer <a href="#rfc.xref.header.referer.1">4. 6</a>, <a href="#rfc.iref.h.16"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3</a>, <a href="#rfc.xref.header.referer.3">C</a></li>4995 <li>Retry-After <a href="#rfc.xref.header.retry-after.1">4. 7</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</a>, <a href="#rfc.iref.h.17"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3</a></li>4996 <li>Server <a href="#rfc.xref.header.server.1">4. 7</a>, <a href="#rfc.iref.h.18"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>4997 <li>User-Agent <a href="#rfc.xref.header.user-agent.1">4. 6</a>, <a href="#rfc.xref.header.user-agent.2">9.1</a>, <a href="#rfc.iref.h.19"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li>4990 <li>Content-Type <a href="#rfc.xref.header.content-type.1">5</a>, <a href="#rfc.xref.header.content-type.2">6.5</a>, <a href="#rfc.xref.header.content-type.3">8.2</a>, <a href="#rfc.iref.h.10"><b>10.9</b></a>, <a href="#rfc.xref.header.content-type.4">11.3.1</a>, <a href="#rfc.xref.header.content-type.5">11.3.2</a></li> 4991 <li>Date <a href="#rfc.xref.header.date.1">4.6</a>, <a href="#rfc.iref.h.11"><b>10.10</b></a>, <a href="#rfc.xref.header.date.2">11.3.2</a></li> 4992 <li>Expect <a href="#rfc.xref.header.expect.1">4.5</a>, <a href="#rfc.xref.header.expect.2">5.5.14</a>, <a href="#rfc.iref.h.12"><b>10.11</b></a>, <a href="#rfc.xref.header.expect.3">11.3.2</a>, <a href="#rfc.xref.header.expect.4">C</a></li> 4993 <li>From <a href="#rfc.xref.header.from.1">4.5</a>, <a href="#rfc.iref.h.13"><b>10.12</b></a>, <a href="#rfc.xref.header.from.2">11.3.2</a></li> 4994 <li>Location <a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4.6</a>, <a href="#rfc.xref.header.location.3">5.4</a>, <a href="#rfc.iref.h.14"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3.2</a>, <a href="#rfc.xref.header.location.5">C</a></li> 4995 <li>Max-Forwards <a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4.5</a>, <a href="#rfc.iref.h.15"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3.2</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li> 4996 <li>MIME-Version <a href="#rfc.xref.mime-version.1">11.3.2</a>, <a href="#rfc.iref.h.20"><b>A.1</b></a></li> 4997 <li>Referer <a href="#rfc.xref.header.referer.1">4.5</a>, <a href="#rfc.iref.h.16"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3.2</a>, <a href="#rfc.xref.header.referer.3">C</a></li> 4998 <li>Retry-After <a href="#rfc.xref.header.retry-after.1">4.6</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</a>, <a href="#rfc.iref.h.17"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3.2</a></li> 4999 <li>Server <a href="#rfc.xref.header.server.1">4.6</a>, <a href="#rfc.iref.h.18"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3.2</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li> 5000 <li>User-Agent <a href="#rfc.xref.header.user-agent.1">4.5</a>, <a href="#rfc.xref.header.user-agent.2">9.1</a>, <a href="#rfc.iref.h.19"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3.2</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li> 4998 5001 </ul> 4999 5002 </li> … … 5005 5008 </li> 5006 5009 <li><a id="rfc.index.L" href="#rfc.index.L"><b>L</b></a><ul> 5007 <li>Location header field <a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4. 7</a>, <a href="#rfc.xref.header.location.3">5.4</a>, <a href="#rfc.iref.l.1"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3</a>, <a href="#rfc.xref.header.location.5">C</a></li>5010 <li>Location header field <a href="#rfc.xref.header.location.1">3.3.4</a>, <a href="#rfc.xref.header.location.2">4.6</a>, <a href="#rfc.xref.header.location.3">5.4</a>, <a href="#rfc.iref.l.1"><b>10.13</b></a>, <a href="#rfc.xref.header.location.4">11.3.2</a>, <a href="#rfc.xref.header.location.5">C</a></li> 5008 5011 </ul> 5009 5012 </li> 5010 5013 <li><a id="rfc.index.M" href="#rfc.index.M"><b>M</b></a><ul> 5011 <li>Max-Forwards header field <a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4. 6</a>, <a href="#rfc.iref.m.9"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li>5014 <li>Max-Forwards header field <a href="#rfc.xref.header.max-forwards.1">3.3.1</a>, <a href="#rfc.xref.header.max-forwards.2">3.3.7</a>, <a href="#rfc.xref.header.max-forwards.3">4.5</a>, <a href="#rfc.iref.m.9"><b>10.14</b></a>, <a href="#rfc.xref.header.max-forwards.4">11.3.2</a>, <a href="#rfc.xref.header.max-forwards.5">C</a></li> 5012 5015 <li>Methods 5013 5016 <ul> … … 5022 5025 </ul> 5023 5026 </li> 5024 <li>MIME-Version header field <a href="#rfc.xref.mime-version.1">11.3 </a>, <a href="#rfc.iref.m.10"><b>A.1</b></a></li>5027 <li>MIME-Version header field <a href="#rfc.xref.mime-version.1">11.3.2</a>, <a href="#rfc.iref.m.10"><b>A.1</b></a></li> 5025 5028 </ul> 5026 5029 </li> … … 5030 5033 </li> 5031 5034 <li><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul> 5032 <li><em>Part1</em> <a href="#rfc.xref.Part1.1">1</a>, <a href="#rfc.xref.Part1.2">1.1</a>, <a href="#rfc.xref.Part1.3">1.2</a>, <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.7">3.3.1</a>, <a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.9">3.3.7</a>, <a href="#rfc.xref.Part1.10">3.3.8</a>, <a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.12">4.5</a>, <a href="#rfc.xref.Part1.13">4.5</a>, <a href="#rfc.xref.Part1.14">4. 5</a>, <a href="#rfc.xref.Part1.15">4.5</a>, <a href="#rfc.xref.Part1.16">4.5</a>, <a href="#rfc.xref.Part1.17">4.6</a>, <a href="#rfc.xref.Part1.18">4.6</a>, <a href="#rfc.xref.Part1.19">4.7</a>, <a href="#rfc.xref.Part1.20">5.2.1</a>, <a href="#rfc.xref.Part1.21">5.2.2</a>, <a href="#rfc.xref.Part1.22">5.3.4</a>, <a href="#rfc.xref.Part1.23">5.3.6</a>, <a href="#rfc.xref.Part1.24">5.5.15</a>, <a href="#rfc.xref.Part1.25">5.6.6</a>, <a href="#rfc.xref.Part1.26">6.4</a>, <a href="#rfc.xref.Part1.27">6.4</a>, <a href="#rfc.xref.Part1.28">6.4</a>, <a href="#rfc.xref.Part1.29">7.1</a>, <a href="#rfc.xref.Part1.30">7.2</a>, <a href="#rfc.xref.Part1.31">8</a>, <a href="#rfc.xref.Part1.32">8.1</a>, <a href="#rfc.xref.Part1.33">10.8</a>, <a href="#rfc.xref.Part1.34">10.11</a>, <a href="#rfc.xref.Part1.35">10.17</a>, <a href="#rfc.xref.Part1.36">10.17</a>, <a href="#rfc.xref.Part1.37">10.18</a>, <a href="#rfc.xref.Part1.38">11.1.2</a>, <a href="#rfc.xref.Part1.39">11.4</a>, <a href="#rfc.xref.Part1.40">11.4.1</a>, <a href="#rfc.xref.Part1.41">11.4.1</a>, <a href="#rfc.xref.Part1.42">11.4.2</a>, <a href="#rfc.xref.Part1.43">11.4.2</a>, <a href="#rfc.xref.Part1.44">11.4.2</a>, <a href="#rfc.xref.Part1.45">13</a>, <a href="#Part1"><b>14.1</b></a>, <a href="#rfc.xref.Part1.46">C</a>, <a href="#rfc.xref.Part1.47">D</a>, <a href="#rfc.xref.Part1.48">D</a>, <a href="#rfc.xref.Part1.49">D</a>, <a href="#rfc.xref.Part1.50">D</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.54">D</a>, <a href="#rfc.xref.Part1.55">D</a>, <a href="#rfc.xref.Part1.56">D</a>, <a href="#rfc.xref.Part1.57">D</a><ul>5035 <li><em>Part1</em> <a href="#rfc.xref.Part1.1">1</a>, <a href="#rfc.xref.Part1.2">1.1</a>, <a href="#rfc.xref.Part1.3">1.2</a>, <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.7">3.3.1</a>, <a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.9">3.3.7</a>, <a href="#rfc.xref.Part1.10">3.3.8</a>, <a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.12">4.5</a>, <a href="#rfc.xref.Part1.13">4.5</a>, <a href="#rfc.xref.Part1.14">4.6</a>, <a href="#rfc.xref.Part1.15">5.2.1</a>, <a href="#rfc.xref.Part1.16">5.2.2</a>, <a href="#rfc.xref.Part1.17">5.3.4</a>, <a href="#rfc.xref.Part1.18">5.3.6</a>, <a href="#rfc.xref.Part1.19">5.5.15</a>, <a href="#rfc.xref.Part1.20">5.6.6</a>, <a href="#rfc.xref.Part1.21">6.4</a>, <a href="#rfc.xref.Part1.22">6.4</a>, <a href="#rfc.xref.Part1.23">6.4</a>, <a href="#rfc.xref.Part1.24">7.1</a>, <a href="#rfc.xref.Part1.25">7.2</a>, <a href="#rfc.xref.Part1.26">8</a>, <a href="#rfc.xref.Part1.27">8.1</a>, <a href="#rfc.xref.Part1.28">10.8</a>, <a href="#rfc.xref.Part1.29">10.11</a>, <a href="#rfc.xref.Part1.30">10.17</a>, <a href="#rfc.xref.Part1.31">10.17</a>, <a href="#rfc.xref.Part1.32">10.18</a>, <a href="#rfc.xref.Part1.33">11.1.2</a>, <a href="#rfc.xref.Part1.34">11.3.1</a>, <a href="#rfc.xref.Part1.35">11.3.1</a>, <a href="#rfc.xref.Part1.36">11.3.1</a>, <a href="#rfc.xref.Part1.37">11.3.1</a>, <a href="#rfc.xref.Part1.38">11.3.1</a>, <a href="#rfc.xref.Part1.39">11.4</a>, <a href="#rfc.xref.Part1.40">11.4.1</a>, <a href="#rfc.xref.Part1.41">11.4.1</a>, <a href="#rfc.xref.Part1.42">11.4.2</a>, <a href="#rfc.xref.Part1.43">11.4.2</a>, <a href="#rfc.xref.Part1.44">11.4.2</a>, <a href="#rfc.xref.Part1.45">13</a>, <a href="#Part1"><b>14.1</b></a>, <a href="#rfc.xref.Part1.46">C</a>, <a href="#rfc.xref.Part1.47">D</a>, <a href="#rfc.xref.Part1.48">D</a>, <a href="#rfc.xref.Part1.49">D</a>, <a href="#rfc.xref.Part1.50">D</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.54">D</a>, <a href="#rfc.xref.Part1.55">D</a>, <a href="#rfc.xref.Part1.56">D</a>, <a href="#rfc.xref.Part1.57">D</a><ul> 5033 5036 <li><em>Section 1.2</em> <a href="#rfc.xref.Part1.3">1.2</a></li> 5034 <li><em>Section 2.3</em> <a href="#rfc.xref.Part1. 22">5.3.4</a></li>5037 <li><em>Section 2.3</em> <a href="#rfc.xref.Part1.17">5.3.4</a></li> 5035 5038 <li><em>Section 2.5</em> <a href="#rfc.xref.Part1.2">1.1</a></li> 5036 <li><em>Section 2.6</em> <a href="#rfc.xref.Part1.2 5">5.6.6</a></li>5039 <li><em>Section 2.6</em> <a href="#rfc.xref.Part1.20">5.6.6</a></li> 5037 5040 <li><em>Section 2.7</em> <a href="#rfc.xref.Part1.4">2</a>, <a href="#rfc.xref.Part1.54">D</a>, <a href="#rfc.xref.Part1.56">D</a>, <a href="#rfc.xref.Part1.57">D</a></li> 5038 <li><em>Section 3.2</em> <a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1. 14">4.5</a>, <a href="#rfc.xref.Part1.35">10.17</a>, <a href="#rfc.xref.Part1.37">10.18</a></li>5041 <li><em>Section 3.2</em> <a href="#rfc.xref.Part1.11">4</a>, <a href="#rfc.xref.Part1.30">10.17</a>, <a href="#rfc.xref.Part1.32">10.18</a>, <a href="#rfc.xref.Part1.36">11.3.1</a></li> 5039 5042 <li><em>Section 3.2.1</em> <a href="#rfc.xref.Part1.48">D</a>, <a href="#rfc.xref.Part1.49">D</a>, <a href="#rfc.xref.Part1.50">D</a></li> 5040 <li><em>Section 3.2.4</em> <a href="#rfc.xref.Part1. 13">4.5</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.55">D</a></li>5041 <li><em>Section 3.3</em> <a href="#rfc.xref.Part1. 23">5.3.6</a>, <a href="#rfc.xref.Part1.30">7.2</a>, <a href="#rfc.xref.Part1.31">8</a>, <a href="#rfc.xref.Part1.38">11.1.2</a></li>5042 <li><em>Section 3.3.2</em> <a href="#rfc.xref.Part1.2 9">7.1</a></li>5043 <li><em>Section 3.2.4</em> <a href="#rfc.xref.Part1.35">11.3.1</a>, <a href="#rfc.xref.Part1.51">D</a>, <a href="#rfc.xref.Part1.52">D</a>, <a href="#rfc.xref.Part1.53">D</a>, <a href="#rfc.xref.Part1.55">D</a></li> 5044 <li><em>Section 3.3</em> <a href="#rfc.xref.Part1.18">5.3.6</a>, <a href="#rfc.xref.Part1.25">7.2</a>, <a href="#rfc.xref.Part1.26">8</a>, <a href="#rfc.xref.Part1.33">11.1.2</a></li> 5045 <li><em>Section 3.3.2</em> <a href="#rfc.xref.Part1.24">7.1</a></li> 5043 5046 <li><em>Section 4</em> <a href="#rfc.xref.Part1.40">11.4.1</a></li> 5044 <li><em>Section 4.1</em> <a href="#rfc.xref.Part1. 16">4.5</a></li>5045 <li><em>Section 4.2.1</em> <a href="#rfc.xref.Part1.2 6">6.4</a>, <a href="#rfc.xref.Part1.42">11.4.2</a></li>5047 <li><em>Section 4.1</em> <a href="#rfc.xref.Part1.38">11.3.1</a></li> 5048 <li><em>Section 4.2.1</em> <a href="#rfc.xref.Part1.21">6.4</a>, <a href="#rfc.xref.Part1.42">11.4.2</a></li> 5046 5049 <li><em>Section 4.2</em> <a href="#rfc.xref.Part1.39">11.4</a>, <a href="#rfc.xref.Part1.41">11.4.1</a></li> 5047 <li><em>Section 4.2.2</em> <a href="#rfc.xref.Part1.2 7">6.4</a>, <a href="#rfc.xref.Part1.43">11.4.2</a></li>5048 <li><em>Section 4.2.3</em> <a href="#rfc.xref.Part1.2 8">6.4</a>, <a href="#rfc.xref.Part1.44">11.4.2</a></li>5049 <li><em>Section 4.3</em> <a href="#rfc.xref.Part1.1 8">4.6</a></li>5050 <li><em>Section 4.2.2</em> <a href="#rfc.xref.Part1.22">6.4</a>, <a href="#rfc.xref.Part1.43">11.4.2</a></li> 5051 <li><em>Section 4.2.3</em> <a href="#rfc.xref.Part1.23">6.4</a>, <a href="#rfc.xref.Part1.44">11.4.2</a></li> 5052 <li><em>Section 4.3</em> <a href="#rfc.xref.Part1.13">4.5</a></li> 5050 5053 <li><em>Section 5.3</em> <a href="#rfc.xref.Part1.5">2</a>, <a href="#rfc.xref.Part1.7">3.3.1</a>, <a href="#rfc.xref.Part1.10">3.3.8</a></li> 5051 <li><em>Section 5.4</em> <a href="#rfc.xref.Part1.1 7">4.6</a></li>5052 <li><em>Section 5.5</em> <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.1 9">4.7</a>, <a href="#rfc.xref.Part1.32">8.1</a>, <a href="#rfc.xref.Part1.33">10.8</a></li>5053 <li><em>Section 5.7</em> <a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.3 6">10.17</a>, <a href="#rfc.xref.Part1.46">C</a></li>5054 <li><em>Section 6.1</em> <a href="#rfc.xref.Part1. 15">4.5</a></li>5055 <li><em>Section 6.3</em> <a href="#rfc.xref.Part1. 20">5.2.1</a>, <a href="#rfc.xref.Part1.34">10.11</a></li>5056 <li><em>Section 6.4</em> <a href="#rfc.xref.Part1. 21">5.2.2</a>, <a href="#rfc.xref.Part1.24">5.5.15</a></li>5054 <li><em>Section 5.4</em> <a href="#rfc.xref.Part1.12">4.5</a></li> 5055 <li><em>Section 5.5</em> <a href="#rfc.xref.Part1.6">2</a>, <a href="#rfc.xref.Part1.14">4.6</a>, <a href="#rfc.xref.Part1.27">8.1</a>, <a href="#rfc.xref.Part1.28">10.8</a></li> 5056 <li><em>Section 5.7</em> <a href="#rfc.xref.Part1.8">3.3.7</a>, <a href="#rfc.xref.Part1.31">10.17</a>, <a href="#rfc.xref.Part1.46">C</a></li> 5057 <li><em>Section 6.1</em> <a href="#rfc.xref.Part1.37">11.3.1</a></li> 5058 <li><em>Section 6.3</em> <a href="#rfc.xref.Part1.15">5.2.1</a>, <a href="#rfc.xref.Part1.29">10.11</a></li> 5059 <li><em>Section 6.4</em> <a href="#rfc.xref.Part1.16">5.2.2</a>, <a href="#rfc.xref.Part1.19">5.5.15</a></li> 5057 5060 <li><em>Section 7.3.1</em> <a href="#rfc.xref.Part1.9">3.3.7</a></li> 5058 5061 <li><em>Section 9</em> <a href="#rfc.xref.Part1.45">13</a></li> 5059 <li><em>Appendix B</em> <a href="#rfc.xref.Part1. 12">4.5</a></li>5062 <li><em>Appendix B</em> <a href="#rfc.xref.Part1.34">11.3.1</a></li> 5060 5063 </ul> 5061 5064 </li> 5062 <li><em>Part4</em> <a href="#rfc.xref.Part4.1">3.3.2</a>, <a href="#rfc.xref.Part4.2">4. 6</a>, <a href="#rfc.xref.Part4.3">4.6</a>, <a href="#rfc.xref.Part4.4">4.6</a>, <a href="#rfc.xref.Part4.5">4.6</a>, <a href="#rfc.xref.Part4.6">4.7</a>, <a href="#rfc.xref.Part4.7">5.1</a>, <a href="#rfc.xref.Part4.8">5.1</a>, <a href="#rfc.xref.Part4.9">5.1</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.11">5.4</a>, <a href="#rfc.xref.Part4.12">8.2</a>, <a href="#rfc.xref.Part4.13">8.2</a>, <a href="#Part4"><b>14.1</b></a>, <a href="#rfc.xref.Part4.14">F.2</a><ul>5065 <li><em>Part4</em> <a href="#rfc.xref.Part4.1">3.3.2</a>, <a href="#rfc.xref.Part4.2">4.5</a>, <a href="#rfc.xref.Part4.3">4.5</a>, <a href="#rfc.xref.Part4.4">4.5</a>, <a href="#rfc.xref.Part4.5">4.5</a>, <a href="#rfc.xref.Part4.6">4.6</a>, <a href="#rfc.xref.Part4.7">5.1</a>, <a href="#rfc.xref.Part4.8">5.1</a>, <a href="#rfc.xref.Part4.9">5.1</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.11">5.4</a>, <a href="#rfc.xref.Part4.12">8.2</a>, <a href="#rfc.xref.Part4.13">8.2</a>, <a href="#Part4"><b>14.1</b></a>, <a href="#rfc.xref.Part4.14">F.2</a><ul> 5063 5066 <li><em>Section 2.2</em> <a href="#rfc.xref.Part4.13">8.2</a></li> 5064 <li><em>Section 2.3</em> <a href="#rfc.xref.Part4.6">4. 7</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.12">8.2</a></li>5065 <li><em>Section 3.1</em> <a href="#rfc.xref.Part4.2">4. 6</a></li>5066 <li><em>Section 3.2</em> <a href="#rfc.xref.Part4.4">4. 6</a></li>5067 <li><em>Section 3.3</em> <a href="#rfc.xref.Part4.3">4. 6</a></li>5068 <li><em>Section 3.4</em> <a href="#rfc.xref.Part4.5">4. 6</a></li>5067 <li><em>Section 2.3</em> <a href="#rfc.xref.Part4.6">4.6</a>, <a href="#rfc.xref.Part4.10">5.3.2</a>, <a href="#rfc.xref.Part4.12">8.2</a></li> 5068 <li><em>Section 3.1</em> <a href="#rfc.xref.Part4.2">4.5</a></li> 5069 <li><em>Section 3.2</em> <a href="#rfc.xref.Part4.4">4.5</a></li> 5070 <li><em>Section 3.3</em> <a href="#rfc.xref.Part4.3">4.5</a></li> 5071 <li><em>Section 3.4</em> <a href="#rfc.xref.Part4.5">4.5</a></li> 5069 5072 <li><em>Section 4</em> <a href="#rfc.xref.Part4.7">5.1</a></li> 5070 5073 <li><em>Section 4.1</em> <a href="#rfc.xref.Part4.8">5.1</a>, <a href="#rfc.xref.Part4.11">5.4</a></li> … … 5072 5075 </ul> 5073 5076 </li> 5074 <li><em>Part5</em> <a href="#rfc.xref.Part5.1">3.3.2</a>, <a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.3">3.3.5</a>, <a href="#rfc.xref.Part5.4">4. 6</a>, <a href="#rfc.xref.Part5.5">4.6</a>, <a href="#rfc.xref.Part5.6">4.7</a>, <a href="#rfc.xref.Part5.7">5.1</a>, <a href="#rfc.xref.Part5.8">5.1</a>, <a href="#rfc.xref.Part5.9">5.1</a>, <a href="#rfc.xref.Part5.10">7.1</a>, <a href="#Part5"><b>14.1</b></a><ul>5077 <li><em>Part5</em> <a href="#rfc.xref.Part5.1">3.3.2</a>, <a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.3">3.3.5</a>, <a href="#rfc.xref.Part5.4">4.5</a>, <a href="#rfc.xref.Part5.5">4.5</a>, <a href="#rfc.xref.Part5.6">4.6</a>, <a href="#rfc.xref.Part5.7">5.1</a>, <a href="#rfc.xref.Part5.8">5.1</a>, <a href="#rfc.xref.Part5.9">5.1</a>, <a href="#rfc.xref.Part5.10">7.1</a>, <a href="#Part5"><b>14.1</b></a><ul> 5075 5078 <li><em>Section 3</em> <a href="#rfc.xref.Part5.7">5.1</a></li> 5076 5079 <li><em>Section 3.1</em> <a href="#rfc.xref.Part5.8">5.1</a></li> 5077 5080 <li><em>Section 3.2</em> <a href="#rfc.xref.Part5.9">5.1</a></li> 5078 <li><em>Section 5.1</em> <a href="#rfc.xref.Part5.6">4. 7</a></li>5081 <li><em>Section 5.1</em> <a href="#rfc.xref.Part5.6">4.6</a></li> 5079 5082 <li><em>Section 5.2</em> <a href="#rfc.xref.Part5.3">3.3.5</a>, <a href="#rfc.xref.Part5.10">7.1</a></li> 5080 <li><em>Section 5.3</em> <a href="#rfc.xref.Part5.4">4. 6</a></li>5081 <li><em>Section 5.4</em> <a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.5">4. 6</a></li>5083 <li><em>Section 5.3</em> <a href="#rfc.xref.Part5.4">4.5</a></li> 5084 <li><em>Section 5.4</em> <a href="#rfc.xref.Part5.2">3.3.2</a>, <a href="#rfc.xref.Part5.5">4.5</a></li> 5082 5085 </ul> 5083 5086 </li> 5084 <li><em>Part6</em> <a href="#rfc.xref.Part6.1">3.2.3</a>, <a href="#rfc.xref.Part6.2">3.3.2</a>, <a href="#rfc.xref.Part6.3">3.3.3</a>, <a href="#rfc.xref.Part6.4">3.3.4</a>, <a href="#rfc.xref.Part6.5">3.3.5</a>, <a href="#rfc.xref.Part6.6">3.3.6</a>, <a href="#rfc.xref.Part6.7">4. 5</a>, <a href="#rfc.xref.Part6.8">4.7</a>, <a href="#rfc.xref.Part6.9">4.7</a>, <a href="#rfc.xref.Part6.10">5.3.1</a>, <a href="#rfc.xref.Part6.11">5.3.4</a>, <a href="#rfc.xref.Part6.12">5.3.4</a>, <a href="#rfc.xref.Part6.13">5.3.4</a>, <a href="#rfc.xref.Part6.14">5.4.1</a>, <a href="#rfc.xref.Part6.15">5.4.2</a>, <a href="#rfc.xref.Part6.16">5.5.9</a>, <a href="#rfc.xref.Part6.17">8.2</a>, <a href="#rfc.xref.Part6.18">9.1</a>, <a href="#rfc.xref.Part6.19">11.2.2</a>, <a href="#Part6"><b>14.1</b></a><ul>5087 <li><em>Part6</em> <a href="#rfc.xref.Part6.1">3.2.3</a>, <a href="#rfc.xref.Part6.2">3.3.2</a>, <a href="#rfc.xref.Part6.3">3.3.3</a>, <a href="#rfc.xref.Part6.4">3.3.4</a>, <a href="#rfc.xref.Part6.5">3.3.5</a>, <a href="#rfc.xref.Part6.6">3.3.6</a>, <a href="#rfc.xref.Part6.7">4.6</a>, <a href="#rfc.xref.Part6.8">4.6</a>, <a href="#rfc.xref.Part6.9">5.3.1</a>, <a href="#rfc.xref.Part6.10">5.3.4</a>, <a href="#rfc.xref.Part6.11">5.3.4</a>, <a href="#rfc.xref.Part6.12">5.3.4</a>, <a href="#rfc.xref.Part6.13">5.4.1</a>, <a href="#rfc.xref.Part6.14">5.4.2</a>, <a href="#rfc.xref.Part6.15">5.5.9</a>, <a href="#rfc.xref.Part6.16">8.2</a>, <a href="#rfc.xref.Part6.17">9.1</a>, <a href="#rfc.xref.Part6.18">11.2.2</a>, <a href="#rfc.xref.Part6.19">11.3.1</a>, <a href="#Part6"><b>14.1</b></a><ul> 5085 5088 <li><em>Section 4.1.1</em> <a href="#rfc.xref.Part6.4">3.3.4</a></li> 5086 <li><em>Section 4.1.2</em> <a href="#rfc.xref.Part6. 10">5.3.1</a>, <a href="#rfc.xref.Part6.13">5.3.4</a>, <a href="#rfc.xref.Part6.14">5.4.1</a>, <a href="#rfc.xref.Part6.15">5.4.2</a>, <a href="#rfc.xref.Part6.16">5.5.9</a></li>5089 <li><em>Section 4.1.2</em> <a href="#rfc.xref.Part6.9">5.3.1</a>, <a href="#rfc.xref.Part6.12">5.3.4</a>, <a href="#rfc.xref.Part6.13">5.4.1</a>, <a href="#rfc.xref.Part6.14">5.4.2</a>, <a href="#rfc.xref.Part6.15">5.5.9</a></li> 5087 5090 <li><em>Section 5</em> <a href="#rfc.xref.Part6.3">3.3.3</a></li> 5088 5091 <li><em>Section 6</em> <a href="#rfc.xref.Part6.5">3.3.5</a>, <a href="#rfc.xref.Part6.6">3.3.6</a></li> 5089 <li><em>Section 7.1</em> <a href="#rfc.xref.Part6. 8">4.7</a></li>5090 <li><em>Section 7.2</em> <a href="#rfc.xref.Part6.1 1">5.3.4</a></li>5091 <li><em>Section 7.3</em> <a href="#rfc.xref.Part6.1 7">8.2</a></li>5092 <li><em>Section 7.5</em> <a href="#rfc.xref.Part6. 9">4.7</a>, <a href="#rfc.xref.Part6.18">9.1</a></li>5093 <li><em>Section 7.6</em> <a href="#rfc.xref.Part6.1 2">5.3.4</a></li>5092 <li><em>Section 7.1</em> <a href="#rfc.xref.Part6.7">4.6</a></li> 5093 <li><em>Section 7.2</em> <a href="#rfc.xref.Part6.10">5.3.4</a></li> 5094 <li><em>Section 7.3</em> <a href="#rfc.xref.Part6.16">8.2</a></li> 5095 <li><em>Section 7.5</em> <a href="#rfc.xref.Part6.8">4.6</a>, <a href="#rfc.xref.Part6.17">9.1</a></li> 5096 <li><em>Section 7.6</em> <a href="#rfc.xref.Part6.11">5.3.4</a></li> 5094 5097 </ul> 5095 5098 </li> 5096 <li><em>Part7</em> <a href="#rfc.xref.Part7.1">4. 6</a>, <a href="#rfc.xref.Part7.2">4.6</a>, <a href="#rfc.xref.Part7.3">4.7</a>, <a href="#rfc.xref.Part7.4">4.7</a>, <a href="#rfc.xref.Part7.5">5.1</a>, <a href="#rfc.xref.Part7.6">5.1</a>, <a href="#rfc.xref.Part7.7">5.1</a>, <a href="#Part7"><b>14.1</b></a><ul>5099 <li><em>Part7</em> <a href="#rfc.xref.Part7.1">4.5</a>, <a href="#rfc.xref.Part7.2">4.5</a>, <a href="#rfc.xref.Part7.3">4.6</a>, <a href="#rfc.xref.Part7.4">4.6</a>, <a href="#rfc.xref.Part7.5">5.1</a>, <a href="#rfc.xref.Part7.6">5.1</a>, <a href="#rfc.xref.Part7.7">5.1</a>, <a href="#Part7"><b>14.1</b></a><ul> 5097 5100 <li><em>Section 3</em> <a href="#rfc.xref.Part7.5">5.1</a></li> 5098 5101 <li><em>Section 3.1</em> <a href="#rfc.xref.Part7.6">5.1</a></li> 5099 5102 <li><em>Section 3.2</em> <a href="#rfc.xref.Part7.7">5.1</a></li> 5100 <li><em>Section 4.1</em> <a href="#rfc.xref.Part7.1">4. 6</a></li>5101 <li><em>Section 4.2</em> <a href="#rfc.xref.Part7.3">4. 7</a></li>5102 <li><em>Section 4.3</em> <a href="#rfc.xref.Part7.2">4. 6</a></li>5103 <li><em>Section 4.4</em> <a href="#rfc.xref.Part7.4">4. 7</a></li>5103 <li><em>Section 4.1</em> <a href="#rfc.xref.Part7.1">4.5</a></li> 5104 <li><em>Section 4.2</em> <a href="#rfc.xref.Part7.3">4.6</a></li> 5105 <li><em>Section 4.3</em> <a href="#rfc.xref.Part7.2">4.5</a></li> 5106 <li><em>Section 4.4</em> <a href="#rfc.xref.Part7.4">4.6</a></li> 5104 5107 </ul> 5105 5108 </li> … … 5110 5113 </li> 5111 5114 <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul> 5112 <li>Referer header field <a href="#rfc.xref.header.referer.1">4. 6</a>, <a href="#rfc.iref.r.2"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3</a>, <a href="#rfc.xref.header.referer.3">C</a></li>5115 <li>Referer header field <a href="#rfc.xref.header.referer.1">4.5</a>, <a href="#rfc.iref.r.2"><b>10.15</b></a>, <a href="#rfc.xref.header.referer.2">11.3.2</a>, <a href="#rfc.xref.header.referer.3">C</a></li> 5113 5116 <li>representation <a href="#rfc.iref.r.1">8</a></li> 5114 5117 <li><em>REST</em> <a href="#rfc.xref.REST.1">3.1</a>, <a href="#REST"><b>14.2</b></a></li> 5115 <li>Retry-After header field <a href="#rfc.xref.header.retry-after.1">4. 7</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</a>, <a href="#rfc.iref.r.3"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3</a></li>5118 <li>Retry-After header field <a href="#rfc.xref.header.retry-after.1">4.6</a>, <a href="#rfc.xref.header.retry-after.2">5.6.4</a>, <a href="#rfc.iref.r.3"><b>10.16</b></a>, <a href="#rfc.xref.header.retry-after.3">11.3.2</a></li> 5116 5119 <li><em>RFC1123</em> <a href="#rfc.xref.RFC1123.1">6.1</a>, <a href="#rfc.xref.RFC1123.2">6.1</a>, <a href="#RFC1123"><b>14.2</b></a><ul> 5117 5120 <li><em>Section 5.2.14</em> <a href="#rfc.xref.RFC1123.2">6.1</a></li> … … 5159 5162 </li> 5160 5163 <li><em>RFC3629</em> <a href="#rfc.xref.RFC3629.1">6.3</a>, <a href="#RFC3629"><b>14.2</b></a></li> 5161 <li><em>RFC3864</em> <a href="#rfc.xref.RFC3864.1"> 4.5</a>, <a href="#rfc.xref.RFC3864.2">4.5</a>, <a href="#rfc.xref.RFC3864.3">11.3</a>, <a href="#RFC3864"><b>14.2</b></a><ul>5162 <li><em>Section 4.1</em> <a href="#rfc.xref.RFC3864.2"> 4.5</a></li>5164 <li><em>RFC3864</em> <a href="#rfc.xref.RFC3864.1">11.3</a>, <a href="#rfc.xref.RFC3864.2">11.3.1</a>, <a href="#RFC3864"><b>14.2</b></a><ul> 5165 <li><em>Section 4.1</em> <a href="#rfc.xref.RFC3864.2">11.3.1</a></li> 5163 5166 </ul> 5164 5167 </li> … … 5180 5183 </ul> 5181 5184 </li> 5182 <li><em>RFC5234</em> <a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2"> 4.5</a>, <a href="#RFC5234"><b>14.1</b></a>, <a href="#rfc.xref.RFC5234.3">D</a><ul>5185 <li><em>RFC5234</em> <a href="#rfc.xref.RFC5234.1">1.2</a>, <a href="#rfc.xref.RFC5234.2">11.3.1</a>, <a href="#RFC5234"><b>14.1</b></a>, <a href="#rfc.xref.RFC5234.3">D</a><ul> 5183 5186 <li><em>Appendix B.1</em> <a href="#rfc.xref.RFC5234.3">D</a></li> 5184 5187 </ul> … … 5195 5198 </li> 5196 5199 <li><em>RFC5789</em> <a href="#rfc.xref.RFC5789.1">3.3.5</a>, <a href="#RFC5789"><b>14.2</b></a></li> 5197 <li><em>RFC5987</em> <a href="#rfc.xref.RFC5987.1"> 4.5</a>, <a href="#RFC5987"><b>14.2</b></a></li>5200 <li><em>RFC5987</em> <a href="#rfc.xref.RFC5987.1">11.3.1</a>, <a href="#RFC5987"><b>14.2</b></a></li> 5198 5201 <li><em>RFC6151</em> <a href="#RFC6151"><b>14.2</b></a>, <a href="#rfc.xref.RFC6151.1">C</a></li> 5199 5202 <li><em>RFC6266</em> <a href="#RFC6266"><b>14.2</b></a>, <a href="#rfc.xref.RFC6266.1">B</a>, <a href="#rfc.xref.RFC6266.2">C</a></li> … … 5203 5206 <li>safe <a href="#rfc.iref.s.1"><b>3.2.1</b></a></li> 5204 5207 <li>selected representation <a href="#rfc.iref.s.43"><b>8.2</b></a></li> 5205 <li>Server header field <a href="#rfc.xref.header.server.1">4. 7</a>, <a href="#rfc.iref.s.44"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li>5208 <li>Server header field <a href="#rfc.xref.header.server.1">4.6</a>, <a href="#rfc.iref.s.44"><b>10.17</b></a>, <a href="#rfc.xref.header.server.2">11.3.2</a>, <a href="#rfc.xref.header.server.3">12.1</a>, <a href="#rfc.xref.header.server.4">C</a></li> 5206 5209 <li>Status Codes 5207 5210 <ul> … … 5261 5264 </li> 5262 5265 <li><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul> 5263 <li>User-Agent header field <a href="#rfc.xref.header.user-agent.1">4. 6</a>, <a href="#rfc.xref.header.user-agent.2">9.1</a>, <a href="#rfc.iref.u.1"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li>5266 <li>User-Agent header field <a href="#rfc.xref.header.user-agent.1">4.5</a>, <a href="#rfc.xref.header.user-agent.2">9.1</a>, <a href="#rfc.iref.u.1"><b>10.18</b></a>, <a href="#rfc.xref.header.user-agent.3">11.3.2</a>, <a href="#rfc.xref.header.user-agent.4">12.1</a></li> 5264 5267 </ul> 5265 5268 </li> -
draft-ietf-httpbis/latest/p2-semantics.xml
r1846 r1847 976 976 977 977 <section title="Payload Metadata Fields" anchor="payload.fields"> 978 </section>979 980 <section title="Considerations for Creating Header Fields" anchor="considerations.for.creating.header.fields">981 <t>982 New header fields are registered using the procedures described in983 <xref target="RFC3864"/>.984 </t>985 <t>986 The requirements for header field names are defined in987 <xref target="RFC3864" x:fmt="of" x:sec="4.1"/>. Authors of specifications988 defining new fields are advised to keep the name as short as practical, and989 not to prefix them with "X-" if they are to be registered (either990 immediately or in the future).991 </t>992 <t>993 New header field values typically have their syntax defined using ABNF994 (<xref target="RFC5234"/>), using the extension defined in &abnf-extension;995 as necessary, and are usually constrained to the range of ASCII characters.996 Header fields needing a greater range of characters can use an encoding997 such as the one defined in <xref target="RFC5987"/>.998 </t>999 <t>1000 Because commas (",") are used as a generic delimiter between field-values,1001 they need to be treated with care if they are allowed in the field-value's1002 payload. Typically, components that might contain a comma are protected with1003 double-quotes using the quoted-string ABNF production (&field-components;).1004 </t>1005 <t>1006 For example, a textual date and a URI (either of which might contain a comma)1007 could be safely carried in field-values like these:1008 </t>1009 <figure><artwork type="example">1010 Example-URI-Field: "http://example.com/a.html,foo",1011 "http://without-a-comma.example.com/"1012 Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005"1013 </artwork></figure>1014 <t>1015 Note that double quote delimiters almost always are used with the1016 quoted-string production; using a different syntax inside double quotes1017 will likely cause unnecessary confusion.1018 </t>1019 <t>1020 Many header fields use a format including (case-insensitively) named1021 parameters (for instance, <x:ref>Content-Type</x:ref>, defined in1022 &header-content-type;). Allowing both unquoted (token) and quoted1023 (quoted-string) syntax for the parameter value enables recipients to use1024 existing parser components. When allowing both forms, the meaning of a1025 parameter value ought to be independent of the syntax used for it (for an1026 example, see the notes on parameter handling for media types in1027 &media-types;).1028 </t>1029 <t>1030 Authors of specifications defining new header fields are advised to consider1031 documenting:1032 <list style="symbols">1033 <x:lt>1034 <t>Whether the field is a single value, or whether it can be a list1035 (delimited by commas; see &header-fields;).</t>1036 <t>If it does not use the list syntax, document how to treat messages1037 where the header field occurs multiple times (a sensible default would1038 be to ignore the header field, but this might not always be the right1039 choice).</t>1040 <t>Note that intermediaries and software libraries might combine1041 multiple header field instances into a single one, despite the header1042 field not allowing this. A robust format enables recipients to discover1043 these situations (good example: "Content-Type", as the comma can only1044 appear inside quoted strings; bad example: "Location", as a comma can1045 occur inside a URI).</t>1046 </x:lt>1047 <x:lt><t>Under what conditions the header field can be used; e.g., only in1048 responses or requests, in all messages, only on responses to a particular1049 request method.</t></x:lt>1050 <x:lt><t>Whether it is appropriate to list the field-name in the1051 <x:ref>Connection</x:ref> header field (i.e., if the header field is to1052 be hop-by-hop, see &header-connection;).</t></x:lt>1053 <x:lt><t>Under what conditions intermediaries are allowed to modify the header1054 field's value, insert or delete it.</t></x:lt>1055 <x:lt><t>How the header field might interact with caching (see1056 <xref target="Part6"/>).</t></x:lt>1057 <x:lt><t>Whether the header field is useful or allowable in trailers (see1058 &chunked-encoding;).</t></x:lt>1059 <x:lt><t>Whether the header field ought to be preserved across redirects.</t></x:lt>1060 </list>1061 </t>1062 978 </section> 1063 979 … … 4311 4227 </section> 4312 4228 4313 <section title="Header Field Registr ation" anchor="header.field.registration">4229 <section title="Header Field Registry" anchor="header.field.registry"> 4314 4230 <t> 4315 4231 HTTP header fields are registered within the Message Header Field Registry 4316 located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/> 4317 (see <xref target="RFC3864"/>). The Message Header Field Registry 4318 shall be updated with the permanent registrations below: 4232 located at <eref target="http://www.iana.org/assignments/message-headers/message-header-index.html"/>, 4233 as defined by <xref target="RFC3864"/>. 4234 </t> 4235 4236 <section title="Considerations for New Header Fields" anchor="considerations.for.new.header.fields"> 4237 <t> 4238 The requirements for header field names are defined in 4239 <xref target="RFC3864" x:fmt="of" x:sec="4.1"/>. Authors of specifications 4240 defining new fields are advised to keep the name as short as practical, and 4241 not to prefix them with "X-" if they are to be registered (either 4242 immediately or in the future). 4243 </t> 4244 <t> 4245 New header field values typically have their syntax defined using ABNF 4246 (<xref target="RFC5234"/>), using the extension defined in &abnf-extension; 4247 as necessary, and are usually constrained to the range of ASCII characters. 4248 Header fields needing a greater range of characters can use an encoding 4249 such as the one defined in <xref target="RFC5987"/>. 4250 </t> 4251 <t> 4252 Because commas (",") are used as a generic delimiter between field-values, 4253 they need to be treated with care if they are allowed in the field-value's 4254 payload. Typically, components that might contain a comma are protected with 4255 double-quotes using the quoted-string ABNF production (&field-components;). 4256 </t> 4257 <t> 4258 For example, a textual date and a URI (either of which might contain a comma) 4259 could be safely carried in field-values like these: 4260 </t> 4261 <figure><artwork type="example"> 4262 Example-URI-Field: "http://example.com/a.html,foo", 4263 "http://without-a-comma.example.com/" 4264 Example-Date-Field: "Sat, 04 May 1996", "Wed, 14 Sep 2005" 4265 </artwork></figure> 4266 <t> 4267 Note that double-quote delimiters almost always are used with the 4268 quoted-string production; using a different syntax inside double-quotes 4269 will likely cause unnecessary confusion. 4270 </t> 4271 <t> 4272 Many header fields use a format including (case-insensitively) named 4273 parameters (for instance, <x:ref>Content-Type</x:ref>, defined in 4274 &header-content-type;). Allowing both unquoted (token) and quoted 4275 (quoted-string) syntax for the parameter value enables recipients to use 4276 existing parser components. When allowing both forms, the meaning of a 4277 parameter value ought to be independent of the syntax used for it (for an 4278 example, see the notes on parameter handling for media types in 4279 &media-types;). 4280 </t> 4281 <t> 4282 Authors of specifications defining new header fields are advised to consider 4283 documenting: 4284 <list style="symbols"> 4285 <x:lt> 4286 <t>Whether the field is a single value, or whether it can be a list 4287 (delimited by commas; see &header-fields;).</t> 4288 <t>If it does not use the list syntax, document how to treat messages 4289 where the header field occurs multiple times (a sensible default would 4290 be to ignore the header field, but this might not always be the right 4291 choice).</t> 4292 <t>Note that intermediaries and software libraries might combine 4293 multiple header field instances into a single one, despite the header 4294 field not allowing this. A robust format enables recipients to discover 4295 these situations (good example: "Content-Type", as the comma can only 4296 appear inside quoted strings; bad example: "Location", as a comma can 4297 occur inside a URI).</t> 4298 </x:lt> 4299 <x:lt><t>Under what conditions the header field can be used; e.g., only in 4300 responses or requests, in all messages, only on responses to a particular 4301 request method.</t></x:lt> 4302 <x:lt><t>Whether it is appropriate to list the field-name in the 4303 <x:ref>Connection</x:ref> header field (i.e., if the header field is to 4304 be hop-by-hop, see &header-connection;).</t></x:lt> 4305 <x:lt><t>Under what conditions intermediaries are allowed to modify the header 4306 field's value, insert or delete it.</t></x:lt> 4307 <x:lt><t>How the header field might interact with caching (see 4308 <xref target="Part6"/>).</t></x:lt> 4309 <x:lt><t>Whether the header field is useful or allowable in trailers (see 4310 &chunked-encoding;).</t></x:lt> 4311 <x:lt><t>Whether the header field ought to be preserved across redirects.</t></x:lt> 4312 </list> 4313 </t> 4314 </section> 4315 4316 <section title="Registrations" anchor="header.field.registration"> 4317 <t> 4318 The Message Header Field Registry shall be updated with the 4319 following permanent registrations: 4319 4320 </t> 4320 4321 <?BEGININC p2-semantics.iana-headers ?> … … 4448 4449 </t> 4449 4450 </section> 4451 </section> 4450 4452 4451 4453 <section title="Content Coding Registry" anchor="content.coding.registry">
Note: See TracChangeset
for help on using the changeset viewer.