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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 06:33:50 +0000 |
| commit | fe39ffb8b90ae4e002ed73fe98617cd590abb467 (patch) | |
| tree | b80e5956907d8aeaaffe4e4f0c068c0e6157ce8b /docs/manual/mod/mod_negotiation.html.en | |
| parent | Initial commit. (diff) | |
| download | apache2-upstream/2.4.56.tar.xz apache2-upstream/2.4.56.zip | |
Adding upstream version 2.4.56.upstream/2.4.56
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/manual/mod/mod_negotiation.html.en')
| -rw-r--r-- | docs/manual/mod/mod_negotiation.html.en | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/docs/manual/mod/mod_negotiation.html.en b/docs/manual/mod/mod_negotiation.html.en new file mode 100644 index 0000000..402b3fc --- /dev/null +++ b/docs/manual/mod/mod_negotiation.html.en @@ -0,0 +1,372 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head> +<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>mod_negotiation - Apache HTTP Server Version 2.4</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Apache Module mod_negotiation</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_negotiation.html" title="English"> en </a> | +<a href="../fr/mod/mod_negotiation.html" hreflang="fr" rel="alternate" title="Français"> fr </a> | +<a href="../ja/mod/mod_negotiation.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Provides for <a href="../content-negotiation.html">content negotiation</a></td></tr> +<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Base</td></tr> +<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>negotiation_module</td></tr> +<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_negotiation.c</td></tr></table> +<h3>Summary</h3> + + <p>Content negotiation, or more accurately content selection, is + the selection of the document that best matches the clients + capabilities, from one of several available documents. There + are two implementations of this.</p> + + <ul> + <li>A type map (a file with the handler + <code>type-map</code>) which explicitly lists the files + containing the variants.</li> + + <li>A Multiviews search (enabled by the <code>Multiviews</code> + <code class="directive"><a href="../mod/core.html#options">Options</a></code>), where the server does + an implicit filename pattern match, and choose from amongst the + results.</li> + </ul> +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3> +<ul id="topics"> +<li><img alt="" src="../images/down.gif" /> <a href="#typemaps">Type maps</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#multiviews">Multiviews</a></li> +</ul><h3 class="directives">Directives</h3> +<ul id="toc"> +<li><img alt="" src="../images/down.gif" /> <a href="#cachenegotiateddocs">CacheNegotiatedDocs</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#forcelanguagepriority">ForceLanguagePriority</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#languagepriority">LanguagePriority</a></li> +</ul> +<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_negotiation">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_negotiation">Report a bug</a></li></ul><h3>See also</h3> +<ul class="seealso"> +<li><code class="directive"><a href="../mod/core.html#options">Options</a></code></li> +<li><code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code></li> +<li><a href="../content-negotiation.html">Content +Negotiation</a></li> +<li><a href="../env.html">Environment Variables</a></li> +<li><a href="#comments_section">Comments</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="typemaps" id="typemaps">Type maps</a></h2> + <p>A type map has a format similar to RFC822 mail headers. It + contains document descriptions separated by blank lines, with + lines beginning with a hash character ('#') treated as + comments. A document description consists of several header + records; records may be continued on multiple lines if the + continuation lines start with spaces. The leading space will be + deleted and the lines concatenated. A header record consists of + a keyword name, which always ends in a colon, followed by a + value. Whitespace is allowed between the header name and value, + and between the tokens of value. The headers allowed are: </p> + + <dl> + <dt><code>Content-Encoding:</code></dt> + <dd>The encoding of the file. Apache only recognizes + encodings that are defined by an <code class="directive"><a href="../mod/mod_mime.html#addencoding">AddEncoding</a></code> directive. + This normally includes the encodings <code>x-compress</code> + for compress'd files, and <code>x-gzip</code> for gzip'd + files. The <code>x-</code> prefix is ignored for encoding + comparisons.</dd> + + <dt><code>Content-Language:</code></dt> + <dd>The language(s) of the variant, as an Internet standard + language tag (<a href="http://www.ietf.org/rfc/rfc1766.txt">RFC 1766</a>). An example is <code>en</code>, + meaning English. If the variant contains more than one + language, they are separated by a comma.</dd> + + <dt><code>Content-Length:</code></dt> + <dd>The length of the file, in bytes. If this header is not + present, then the actual length of the file is used.</dd> + + <dt><code>Content-Type:</code></dt> + + <dd> + The <a class="glossarylink" href="../glossary.html#mime-type" title="see glossary">MIME media type</a> of + the document, with optional parameters. Parameters are + separated from the media type and from one another by a + semi-colon, with a syntax of <code>name=value</code>. Common + parameters include: + + <dl> + <dt><code>level</code></dt> + <dd>an integer specifying the version of the media type. + For <code>text/html</code> this defaults to 2, otherwise + 0.</dd> + + <dt><code>qs</code></dt> + <dd>a floating-point number with a value in the range 0[.000] + to 1[.000], indicating the relative 'quality' of this variant + compared to the other available variants, independent of + the client's capabilities. For example, a jpeg file is + usually of higher source quality than an ascii file if it + is attempting to represent a photograph. However, if the + resource being represented is ascii art, then an ascii + file would have a higher source quality than a jpeg file. + All <code>qs</code> values are therefore specific to a given + resource.</dd> + </dl> + + <div class="example"><h3>Example</h3><p><code> + Content-Type: image/jpeg; qs=0.8 + </code></p></div> + </dd> + + <dt><code>URI:</code></dt> + <dd>uri of the file containing the variant (of the given + media type, encoded with the given content encoding). These + are interpreted as URLs relative to the map file; they must + be on the same server, and they must refer to files to + which the client would be granted access if they were to be + requested directly.</dd> + + <dt><code>Body:</code></dt> + <dd>The actual content of the resource may + be included in the type-map file using the Body header. This + header must contain a string that designates a delimiter for + the body content. Then all following lines in the type map + file will be considered part of the resource body until the + delimiter string is found. + + <div class="example"><h3>Example:</h3><p><code> + Body:----xyz----<br /> + <html><br /> + <body><br /> + <p>Content of the page.</p><br /> + </body><br /> + </html><br /> + ----xyz---- + </code></p></div> + </dd> + </dl> + + <p>Consider, for example, a resource called + <code>document.html</code> which is available in English, French, + and German. The files for each of these are called + <code>document.html.en</code>, <code>document.html.fr</code>, and + <code>document.html.de</code>, respectively. The type map file will + be called <code>document.html.var</code>, and will contain the + following:</p> + + <div class="example"><p><code> + URI: document.html<br /> + <br /> + Content-language: en<br /> + Content-type: text/html<br /> + URI: document.html.en<br /> + <br /> + Content-language: fr<br /> + Content-type: text/html<br /> + URI: document.html.fr<br /> + <br /> + Content-language: de<br /> + Content-type: text/html<br /> + URI: document.html.de<br /> + <br /> + + </code></p></div> + + <p>All four of these files should be placed in the same directory, + and the <code>.var</code> file should be associated with the + <code>type-map</code> handler with an <code class="directive"><a href="../mod/mod_mime.html#addhandler">AddHandler</a></code> directive:</p> + + <pre class="prettyprint lang-config">AddHandler type-map .var</pre> + + + <p>A request for <code>document.html.var</code> in this directory will + result in choosing the variant which most closely matches the language preference + specified in the user's <code>Accept-Language</code> request + header.</p> + + <p>If <code>Multiviews</code> is enabled, and <code class="directive"><a href="../mod/mod_mime.html#multiviewsmatch">MultiviewsMatch</a></code> is set to "handlers" or "any", a request to + <code>document.html</code> will discover <code>document.html.var</code> and + continue negotiating with the explicit type map.</p> + + <p>Other configuration directives, such as <code class="directive"><a href="../mod/mod_alias.html#alias">Alias</a></code> can be used to map <code>document.html</code> to + <code>document.html.var</code>.</p> + +</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="multiviews" id="multiviews">Multiviews</a></h2> + <p>A Multiviews search is enabled by the <code>Multiviews</code> + <code class="directive"><a href="../mod/core.html#options">Options</a></code>. If the server receives a + request for <code>/some/dir/foo</code> and + <code>/some/dir/foo</code> does <em>not</em> exist, then the + server reads the directory looking for all files named + <code>foo.*</code>, and effectively fakes up a type map which + names all those files, assigning them the same media types and + content-encodings it would have if the client had asked for one + of them by name. It then chooses the best match to the client's + requirements, and returns that document.</p> + + <p>The <code class="directive"><a href="../mod/mod_mime.html#multiviewsmatch">MultiviewsMatch</a></code> + directive configures whether Apache will consider files + that do not have content negotiation meta-information assigned + to them when choosing files.</p> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="CacheNegotiatedDocs" id="CacheNegotiatedDocs">CacheNegotiatedDocs</a> <a name="cachenegotiateddocs" id="cachenegotiateddocs">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Allows content-negotiated documents to be +cached by proxy servers</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheNegotiatedDocs On|Off</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheNegotiatedDocs Off</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_negotiation</td></tr> +</table> + <p>If set, this directive allows content-negotiated documents + to be cached by proxy servers. This could mean that clients + behind those proxys could retrieve versions of the documents + that are not the best match for their abilities, but it will + make caching more efficient.</p> + + <p>This directive only applies to requests which come from + HTTP/1.0 browsers. HTTP/1.1 provides much better control over + the caching of negotiated documents, and this directive has no + effect in responses to HTTP/1.1 requests.</p> + + +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="ForceLanguagePriority" id="ForceLanguagePriority">ForceLanguagePriority</a> <a name="forcelanguagepriority" id="forcelanguagepriority">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Action to take if a single acceptable document is not +found</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ForceLanguagePriority None|Prefer|Fallback [Prefer|Fallback]</code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ForceLanguagePriority Prefer</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr> +<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_negotiation</td></tr> +</table> + <p>The <code class="directive">ForceLanguagePriority</code> directive uses + the given <code class="directive"><a href="#languagepriority">LanguagePriority</a></code> to satisfy + negotiation where the server could otherwise not return a single + matching document.</p> + + <p><code>ForceLanguagePriority Prefer</code> uses + <code>LanguagePriority</code> to serve a one valid result, rather + than returning an HTTP result 300 (MULTIPLE CHOICES) when there + are several equally valid choices. If the directives below were + given, and the user's <code>Accept-Language</code> header assigned + <code>en</code> and <code>de</code> each as quality <code>.500</code> + (equally acceptable) then the first matching variant, <code>en</code>, + will be served.</p> + + <pre class="prettyprint lang-config">LanguagePriority en fr de +ForceLanguagePriority Prefer</pre> + + + <p><code>ForceLanguagePriority Fallback</code> uses + <code class="directive"><a href="#languagepriority">LanguagePriority</a></code> to + serve a valid result, rather than returning an HTTP result 406 + (NOT ACCEPTABLE). If the directives below were given, and the user's + <code>Accept-Language</code> only permitted an <code>es</code> + language response, but such a variant isn't found, then the first + variant from the <code class="directive"><a href="#languagepriority">LanguagePriority</a></code> list below will be served.</p> + + <pre class="prettyprint lang-config">LanguagePriority en fr de +ForceLanguagePriority Fallback</pre> + + + <p>Both options, <code>Prefer</code> and <code>Fallback</code>, may be + specified, so either the first matching variant from <code class="directive"><a href="#languagepriority">LanguagePriority</a></code> will be served if + more than one variant is acceptable, or first available document will + be served if none of the variants matched the client's acceptable list + of languages.</p> + +<h3>See also</h3> +<ul> +<li><code class="directive"><a href="../mod/mod_mime.html#addlanguage">AddLanguage</a></code></li> +</ul> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="LanguagePriority" id="LanguagePriority">LanguagePriority</a> <a name="languagepriority" id="languagepriority">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The precedence of language variants for cases where +the client does not express a preference</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LanguagePriority <var>MIME-lang</var> [<var>MIME-lang</var>] +...</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr> +<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>FileInfo</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_negotiation</td></tr> +</table> + <p>The <code class="directive">LanguagePriority</code> sets the precedence + of language variants for the case where the client does not + express a preference, when handling a Multiviews request. The list + of <var>MIME-lang</var> are in order of decreasing preference.</p> + + <pre class="prettyprint lang-config">LanguagePriority en fr de</pre> + + + <p>For a request for <code>foo.html</code>, where + <code>foo.html.fr</code> and <code>foo.html.de</code> both + existed, but the browser did not express a language preference, + then <code>foo.html.fr</code> would be returned.</p> + + <p>Note that this directive only has an effect if a 'best' + language cannot be determined by any other means or the <code class="directive"><a href="#forcelanguagepriority">ForceLanguagePriority</a></code> directive + is not <code>None</code>. In general, the client determines the + language preference, not the server.</p> + +<h3>See also</h3> +<ul> +<li><code class="directive"><a href="../mod/mod_mime.html#addlanguage">AddLanguage</a></code></li> +</ul> +</div> +</div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../en/mod/mod_negotiation.html" title="English"> en </a> | +<a href="../fr/mod/mod_negotiation.html" hreflang="fr" rel="alternate" title="Français"> fr </a> | +<a href="../ja/mod/mod_negotiation.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div> +<script type="text/javascript"><!--//--><![CDATA[//><!-- +var comments_shortname = 'httpd'; +var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/mod_negotiation.html'; +(function(w, d) { + if (w.location.hostname.toLowerCase() == "httpd.apache.org") { + d.write('<div id="comments_thread"><\/div>'); + var s = d.createElement('script'); + s.type = 'text/javascript'; + s.async = true; + s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; + (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); + } + else { + d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); + } +})(window, document); +//--><!]]></script></div><div id="footer"> +<p class="apache">Copyright 2023 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- +if (typeof(prettyPrint) !== 'undefined') { + prettyPrint(); +} +//--><!]]></script> +</body></html>
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