Changeset 2072 for draft-ietf-httpbis/latest/p2-semantics.html
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- 31/12/12 10:51:33 (9 years ago)
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draft-ietf-httpbis/latest/p2-semantics.html
r2071 r2072 449 449 } 450 450 @bottom-center { 451 content: "Expires July 3, 2013";451 content: "Expires July 4, 2013"; 452 452 } 453 453 @bottom-right { … … 495 495 <meta name="dct.creator" content="Reschke, J. F."> 496 496 <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p2-semantics-latest"> 497 <meta name="dct.issued" scheme="ISO8601" content="2012-12-3 0">497 <meta name="dct.issued" scheme="ISO8601" content="2012-12-31"> 498 498 <meta name="dct.replaces" content="urn:ietf:rfc:2616"> 499 499 <meta name="dct.abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypertext information systems. This document defines the semantics of HTTP/1.1 messages, as expressed by request methods, request header fields, response status codes, and response header fields, along with the payload of messages (metadata and body content) and mechanisms for content negotiation."> … … 523 523 <tr> 524 524 <td class="left">Intended status: Standards Track</td> 525 <td class="right">December 3 0, 2012</td>525 <td class="right">December 31, 2012</td> 526 526 </tr> 527 527 <tr> 528 <td class="left">Expires: July 3, 2013</td>528 <td class="left">Expires: July 4, 2013</td> 529 529 <td class="right"></td> 530 530 </tr> … … 554 554 in progress”. 555 555 </p> 556 <p>This Internet-Draft will expire on July 3, 2013.</p>556 <p>This Internet-Draft will expire on July 4, 2013.</p> 557 557 <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1> 558 558 <p>Copyright © 2012 IETF Trust and the persons identified as the document authors. All rights reserved.</p> … … 835 835 in <a href="p1-messaging.html#uri" title="Uniform Resource Identifiers">Section 2.7</a> of <a href="#Part1" id="rfc.xref.Part1.4"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing">[Part1]</cite></a>. 836 836 </p> 837 <p id="rfc.section.2.p.2">When a client constructs an HTTP/1.1 request message, it sends the "target URI" in one of various forms, as defined in (<a href="p1-messaging.html#request-target" title="Request Target">Section 5.3</a> of <a href="#Part1" id="rfc.xref.Part1.5"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing">[Part1]</cite></a>). When a request is received, the server reconstructs an "effective request URI"for 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.Part1.6"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing">[Part1]</cite></a>).837 <p id="rfc.section.2.p.2">When a client constructs an HTTP/1.1 request message, it sends the <a href="p1-messaging.html#target-resource" class="smpl">target URI</a> in one of various forms, as defined in (<a href="p1-messaging.html#request-target" title="Request Target">Section 5.3</a> of <a href="#Part1" id="rfc.xref.Part1.5"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing">[Part1]</cite></a>). When a request is received, the server reconstructs an <a href="p1-messaging.html#effective.request.uri" class="smpl">effective request URI</a> for 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.Part1.6"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing">[Part1]</cite></a>). 838 838 </p> 839 839 <p id="rfc.section.2.p.3">One design goal of HTTP is to separate resource identification from request semantics, which is made possible by vesting the … … 1822 1822 <a href="#header.accept" class="smpl">accept-ext</a> = <a href="#imported.abnf" class="smpl">OWS</a> ";" <a href="#imported.abnf" class="smpl">OWS</a> <a href="#imported.abnf" class="smpl">token</a> [ "=" <a href="#imported.abnf" class="smpl">word</a> ] 1823 1823 </pre><p id="rfc.section.5.3.2.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating 1824 all subtypes of that type. The media-range <em class="bcp14">MAY</em> include media type parameters that are applicable to that range. 1825 </p> 1826 <p id="rfc.section.5.3.2.p.4">Each media-range <em class="bcp14">MAY</em> be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative weight, as defined in <a href="#quality.values" title="Quality Values">Section 5.3.1</a>. The first "q" parameter (if any) separates the media-range parameter(s) from the accept-params. 1824 all subtypes of that type. The media-range can include media type parameters that are applicable to that range. 1825 </p> 1826 <p id="rfc.section.5.3.2.p.4">Each media-range might be followed by zero or more applicable media type parameters (e.g., <a href="#charset" class="smpl">charset</a>), an optional "q" parameter for indicating a relative weight (<a href="#quality.values" title="Quality Values">Section 5.3.1</a>), and then zero or more extension parameters. The "q" parameter is necessary if any accept-ext are present, since it acts 1827 as a separator between the two parameter sets. 1827 1828 </p> 1828 1829 <div class="note" id="rfc.section.5.3.2.p.5"> … … 2069 2070 <div id="rfc.iref.r.2"></div> 2070 2071 <h3 id="rfc.section.5.5.2"><a href="#rfc.section.5.5.2">5.5.2</a> <a id="header.referer" href="#header.referer">Referer</a></h3> 2071 <p id="rfc.section.5.5.2.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the target URI was obtained 2072 (the "referrer", although the header field is misspelled.). 2073 </p> 2074 <p id="rfc.section.5.5.2.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching, 2075 etc. It also allows obsolete or mistyped links to be traced for maintenance. Some servers use Referer as a means of controlling 2076 where they allow links from (so-called "deep linking"), but legitimate requests do not always contain a Referer header field. 2077 </p> 2078 <p id="rfc.section.5.5.2.p.3">If the target URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard), the Referer 2079 field <em class="bcp14">MUST</em> either be sent with the value "about:blank", or not be sent at all. Note that this requirement does not apply to sources with 2080 non-HTTP URIs (e.g., FTP). 2072 <p id="rfc.section.5.5.2.p.1">The "Referer" [sic] header field allows the user agent to specify a URI reference for the resource from which the <a href="p1-messaging.html#target-resource" class="smpl">target URI</a> was obtained (i.e., the "referrer", though the field name is misspelled). A user agent <em class="bcp14">MUST</em> exclude any fragment or userinfo components <a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a> when generating the Referer field value. 2081 2073 </p> 2082 2074 <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.35"></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> 2083 </pre><p id="rfc.section.5.5.2.p.5">Example:</p> 2075 </pre><p id="rfc.section.5.5.2.p.3">Referer allows servers to generate back-links to other resources for simple analytics, logging, optimized caching, etc. It 2076 also allows obsolete or mistyped links to be found for maintenance. Some servers use Referer as a means of denying links from 2077 other sites (so-called "deep linking") or restricting cross-site request forgery (CSRF), but not all requests contain a Referer 2078 header field. 2079 </p> 2080 <p id="rfc.section.5.5.2.p.4">Example:</p> 2084 2081 <div id="rfc.figure.u.37"></div><pre class="text"> Referer: http://www.example.org/hypertext/Overview.html 2085 </pre><p id="rfc.section.5.5.2.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 9.4</a> for security considerations. 2082 </pre><p id="rfc.section.5.5.2.p.6">If the target URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard, or an entry 2083 within the user's bookmarks/favorites), the user agent <em class="bcp14">MUST</em> either exclude Referer or send it with a value of "about:blank". 2084 </p> 2085 <p id="rfc.section.5.5.2.p.7">The Referer field has the potential to reveal information about the request context or browsing history of the user, which 2086 is a privacy concern if the referring resource's identifier reveals personal information (such as an account name) or a resource 2087 that is supposed to be confidential (such as behind a firewall or internal to a secured service). Most general-purpose user 2088 agents do not send the Referer header field when the referring resource is a local "file" or "data" URI. A user agent <em class="bcp14">SHOULD NOT</em> send a <a href="#header.referer" class="smpl">Referer</a> header field in a (non-secure) HTTP request if the referring page was received with a secure protocol. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section 9.4</a> for additional security considerations. 2089 </p> 2090 <p id="rfc.section.5.5.2.p.8">Some intermediaries have been known to indiscriminately remove Referer header fields from outgoing requests. This has the 2091 unfortunate side-effect of interfering with protection against CSRF attacks, which can be far more harmful to their users. 2092 Intermediaries and user agent extensions that wish to limit information disclosure in Referer ought to restrict their changes 2093 to specific edits, such as replacing internal domain names with pseudonyms or truncating the query and/or path components. 2094 Intermediaries <em class="bcp14">SHOULD NOT</em> modify or delete the Referer field when the field value shares the same scheme and host as the request target. 2086 2095 </p> 2087 2096 <div id="rfc.iref.u.1"></div> … … 2908 2917 </p> 2909 2918 <div id="rfc.figure.u.51"></div><pre class="inline"><span id="rfc.iref.g.56"></span> <a href="#header.location" class="smpl">Location</a> = <a href="#imported.abnf" class="smpl">URI-reference</a> 2910 </pre><p id="rfc.section.7.1.2.p.3">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986. 1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>). If the original URI, as navigated to by the user agent, contains a fragment identifier, and the Location value does not,2919 </pre><p id="rfc.section.7.1.2.p.3">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.3"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>). If the original URI, as navigated to by the user agent, contains a fragment identifier, and the Location value does not, 2911 2920 then the original URI's fragment identifier is appended to the Location value. 2912 2921 </p> … … 3800 3809 </p> 3801 3810 <h2 id="rfc.section.9.4"><a href="#rfc.section.9.4">9.4</a> <a id="encoding.sensitive.information.in.uris" href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></h2> 3802 <p id="rfc.section.9.4.p.1">Because the source of a link might be private information or might reveal an otherwise private information source, it is strongly 3803 recommended that the user be able to select whether or not the <a href="#header.referer" class="smpl">Referer</a> field is sent. For example, a browser client could have a toggle switch for browsing openly/anonymously, which would respectively 3804 enable/disable the sending of Referer and From information. 3805 </p> 3806 <p id="rfc.section.9.4.p.2">Clients <em class="bcp14">SHOULD NOT</em> include a <a href="#header.referer" class="smpl">Referer</a> header field in a (non-secure) HTTP request if the referring page was transferred with a secure protocol. 3811 <p id="rfc.section.9.4.p.1">URIs are intended to be shared, not secured, even when they identify secure resources. URIs are often shown on displays, added 3812 to templates when a page is printed, and stored in a variety of unprotected bookmark lists. It is therefore unwise to include 3813 information within a URI that is sensitive, personally identifiable, or a risk to disclose. 3814 </p> 3815 <p id="rfc.section.9.4.p.2">Since the Referer header field tells a target site about the context that resulted in a request, it has the potential to reveal 3816 information about the user's immediate browsing history and any personal information that might be found in the referring 3817 resource's URI. Further discussion of Referer considerations can be found in <a href="#header.referer" id="rfc.xref.header.referer.3" title="Referer">Section 5.5.2</a>. 3807 3818 </p> 3808 3819 <p id="rfc.section.9.4.p.3">Authors of services <em class="bcp14">SHOULD NOT</em> use GET-based forms for the submission of sensitive data because that data will be placed in the request-target. Many existing 3809 3820 servers, proxies, and user agents log or display the request-target in places where it might be visible to third parties. 3810 Such services canuse POST-based form submission instead.3821 Such services ought to use POST-based form submission instead. 3811 3822 </p> 3812 3823 <h2 id="rfc.section.9.5"><a href="#rfc.section.9.5">9.5</a> <a id="location.spoofing-leakage" href="#location.spoofing-leakage">Location Header Fields: Spoofing and Information Leakage</a></h2> … … 4153 4164 <p id="rfc.section.C.p.16">Requirements for sending the Date header field have been clarified. (<a href="#header.date" id="rfc.xref.header.date.4" title="Date">Section 7.1.1.2</a>) 4154 4165 </p> 4155 <p id="rfc.section.C.p.17">The <a href="#header.referer" class="smpl">Referer</a> header field can now have a value of "about:blank" as an alternative to not sending a Referer header field. (<a href="#header.referer" id="rfc.xref.header.referer. 3" title="Referer">Section 5.5.2</a>)4166 <p id="rfc.section.C.p.17">The <a href="#header.referer" class="smpl">Referer</a> header field can now have a value of "about:blank" as an alternative to not sending a Referer header field. (<a href="#header.referer" id="rfc.xref.header.referer.4" title="Referer">Section 5.5.2</a>) 4156 4167 </p> 4157 4168 <p id="rfc.section.C.p.18">The <a href="#status.201" class="smpl">201 (Created)</a> status code can indicate that more than one resource has been created (as well as just one). … … 4653 4664 </li> 4654 4665 <li><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul> 4655 <li>Referer header field <a href="#rfc.xref.header.referer.1">5.5</a>, <a href="#rfc.iref.r.2"><b>5.5.2</b></a>, <a href="#rfc.xref.header.referer.2">8.3.2</a>, <a href="#rfc.xref.header.referer.3"> C</a></li>4666 <li>Referer header field <a href="#rfc.xref.header.referer.1">5.5</a>, <a href="#rfc.iref.r.2"><b>5.5.2</b></a>, <a href="#rfc.xref.header.referer.2">8.3.2</a>, <a href="#rfc.xref.header.referer.3">9.4</a>, <a href="#rfc.xref.header.referer.4">C</a></li> 4656 4667 <li>representation <a href="#rfc.iref.r.1">3</a></li> 4657 4668 <li><em>REST</em> <a href="#rfc.xref.REST.1">3</a>, <a href="#rfc.xref.REST.2">4.1</a>, <a href="#REST"><b>11.2</b></a></li> … … 4701 4712 </li> 4702 4713 <li><em>RFC2978</em> <a href="#rfc.xref.RFC2978.1">3.1.1.2</a>, <a href="#RFC2978"><b>11.2</b></a></li> 4703 <li><em>RFC3986</em> <a href="#rfc.xref.RFC3986.1"> 7.1.2</a>, <a href="#rfc.xref.RFC3986.2">7.1.2</a>, <a href="#RFC3986"><b>11.1</b></a><ul>4704 <li><em>Section 4.2</em> <a href="#rfc.xref.RFC3986. 1">7.1.2</a></li>4705 <li><em>Section 5</em> <a href="#rfc.xref.RFC3986. 2">7.1.2</a></li>4714 <li><em>RFC3986</em> <a href="#rfc.xref.RFC3986.1">5.5.2</a>, <a href="#rfc.xref.RFC3986.2">7.1.2</a>, <a href="#rfc.xref.RFC3986.3">7.1.2</a>, <a href="#RFC3986"><b>11.1</b></a><ul> 4715 <li><em>Section 4.2</em> <a href="#rfc.xref.RFC3986.2">7.1.2</a></li> 4716 <li><em>Section 5</em> <a href="#rfc.xref.RFC3986.3">7.1.2</a></li> 4706 4717 </ul> 4707 4718 </li> … … 4756 4767 </li> 4757 4768 <li><a id="rfc.index.T" href="#rfc.index.T"><b>T</b></a><ul> 4758 <li>TRACE method <a href="#rfc.xref.TRACE.1">4.1</a>, <a href="#rfc.iref.t.1"><b>4.3.8</b></a>, <a href="#rfc.xref.TRACE.2">5.1.1</a>, <a href="#rfc.xref.TRACE.3">8.1.3</a>, <a href="#rfc.xref.TRACE.4">9.3</a>, <a href="#rfc.extref.t. 48">C</a>, <a href="#rfc.xref.TRACE.5">C</a></li>4769 <li>TRACE method <a href="#rfc.xref.TRACE.1">4.1</a>, <a href="#rfc.iref.t.1"><b>4.3.8</b></a>, <a href="#rfc.xref.TRACE.2">5.1.1</a>, <a href="#rfc.xref.TRACE.3">8.1.3</a>, <a href="#rfc.xref.TRACE.4">9.3</a>, <a href="#rfc.extref.t.50">C</a>, <a href="#rfc.xref.TRACE.5">C</a></li> 4759 4770 </ul> 4760 4771 </li>
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