mirror of
https://github.com/apache/httpd.git
synced 2025-11-03 17:53:20 +03:00
dc1f51bb92
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1357941 13f79535-47bb-0310-9956-ffa450edef68
278 lines
16 KiB
XML
278 lines
16 KiB
XML
<?xml version="1.0" encoding="ISO-8859-1"?>
|
||
<!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><!--
|
||
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
|
||
This file is generated from xml source: DO NOT EDIT
|
||
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
|
||
-->
|
||
<title>mod_expires - Apache HTTP Server</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.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 2.5</p>
|
||
<img alt="" src="../images/feather.gif" /></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 2.5</a> > <a href="./">Modules</a></div>
|
||
<div id="page-content">
|
||
<div id="preamble"><h1>Apache Module mod_expires</h1>
|
||
<div class="toplang">
|
||
<p><span>Available Languages: </span><a href="../en/mod/mod_expires.html" title="English"> en </a> |
|
||
<a href="../fr/mod/mod_expires.html" hreflang="fr" rel="alternate" title="Fran<61>ais"> fr </a> |
|
||
<a href="../ja/mod/mod_expires.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
|
||
<a href="../ko/mod/mod_expires.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
|
||
</div>
|
||
<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Generation of <code>Expires</code> and
|
||
<code>Cache-Control</code> HTTP headers according to user-specified
|
||
criteria</td></tr>
|
||
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
|
||
<tr><th><a href="module-dict.html#ModuleIdentifier">Module<EFBFBD>Identifier:</a></th><td>expires_module</td></tr>
|
||
<tr><th><a href="module-dict.html#SourceFile">Source<EFBFBD>File:</a></th><td>mod_expires.c</td></tr></table>
|
||
<h3>Summary</h3>
|
||
|
||
<p>This module controls the setting of the <code>Expires</code>
|
||
HTTP header and the <code>max-age</code> directive of the
|
||
<code>Cache-Control</code> HTTP header in server responses. The
|
||
expiration date can set to be relative to either the time the
|
||
source file was last modified, or to the time of the client
|
||
access.</p>
|
||
|
||
<p>These HTTP headers are an instruction to the client about the
|
||
document's validity and persistence. If cached, the document may
|
||
be fetched from the cache rather than from the source until this
|
||
time has passed. After that, the cache copy is considered
|
||
"expired" and invalid, and a new copy must be obtained from the
|
||
source.</p>
|
||
|
||
<p>To modify <code>Cache-Control</code> directives other than
|
||
<code>max-age</code> (see <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9">RFC
|
||
2616 section 14.9</a>), you can use the <code class="directive"><a href="../mod/mod_headers.html#header">Header</a></code> directive.</p>
|
||
|
||
<p> When the <code>Expires</code> header is already part of the response
|
||
generated by the server, for example when generated by a CGI script or
|
||
proxied from an origin server, this module does not change or add
|
||
an <code>Expires</code> or <code>Cache-Control</code> header.</p>
|
||
</div>
|
||
<div id="quickview"><h3 class="directives">Directives</h3>
|
||
<ul id="toc">
|
||
<li><img alt="" src="../images/down.gif" /> <a href="#expiresactive">ExpiresActive</a></li>
|
||
<li><img alt="" src="../images/down.gif" /> <a href="#expiresbytype">ExpiresByType</a></li>
|
||
<li><img alt="" src="../images/down.gif" /> <a href="#expiresdefault">ExpiresDefault</a></li>
|
||
</ul>
|
||
<h3>Topics</h3>
|
||
<ul id="topics">
|
||
<li><img alt="" src="../images/down.gif" /> <a href="#AltSyn">Alternate Interval Syntax</a></li>
|
||
</ul><ul class="seealso"><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="AltSyn" id="AltSyn">Alternate Interval Syntax</a></h2>
|
||
<p>The <code class="directive"><a href="#expiresdefault">ExpiresDefault</a></code> and
|
||
<code class="directive"><a href="#expiresbytype">ExpiresByType</a></code> directives
|
||
can also be defined in a more readable syntax of the form:</p>
|
||
|
||
<pre class="prettyprint lang-config">
|
||
ExpiresDefault "<var>base</var> [plus <var>num</var> <var>type</var>] [<var>num</var> <var>type</var>] ..."
|
||
ExpiresByType type/encoding "<var>base</var> [plus <var>num</var> <var>type</var>] [<var>num</var> <var>type</var>] ..."
|
||
</pre>
|
||
|
||
|
||
<p>where <var>base</var> is one of:</p>
|
||
|
||
<ul>
|
||
<li><code>access</code></li>
|
||
|
||
<li><code>now</code> (equivalent to
|
||
'<code>access</code>')</li>
|
||
|
||
<li><code>modification</code></li>
|
||
</ul>
|
||
|
||
<p>The <code>plus</code> keyword is optional. <var>num</var>
|
||
should be an integer value [acceptable to <code>atoi()</code>],
|
||
and <var>type</var> is one of:</p>
|
||
|
||
<ul>
|
||
<li><code>years</code></li>
|
||
<li><code>months</code></li>
|
||
<li><code>weeks</code></li>
|
||
<li><code>days</code></li>
|
||
<li><code>hours</code></li>
|
||
<li><code>minutes</code></li>
|
||
<li><code>seconds</code></li>
|
||
</ul>
|
||
|
||
<p>For example, any of the following directives can be used to
|
||
make documents expire 1 month after being accessed, by
|
||
default:</p>
|
||
|
||
<pre class="prettyprint lang-config">
|
||
ExpiresDefault "access plus 1 month"
|
||
ExpiresDefault "access plus 4 weeks"
|
||
ExpiresDefault "access plus 30 days"
|
||
</pre>
|
||
|
||
|
||
<p>The expiry time can be fine-tuned by adding several
|
||
'<var>num</var> <var>type</var>' clauses:</p>
|
||
|
||
<pre class="prettyprint lang-config">
|
||
ExpiresByType text/html "access plus 1 month 15 days 2 hours"
|
||
ExpiresByType image/gif "modification plus 5 hours 3 minutes"
|
||
</pre>
|
||
|
||
|
||
<p>Note that if you use a modification date based setting, the
|
||
Expires header will <strong>not</strong> be added to content
|
||
that does not come from a file on disk. This is due to the fact
|
||
that there is no modification time for such content.</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="ExpiresActive" id="ExpiresActive">ExpiresActive</a> <a name="expiresactive" id="expiresactive">Directive</a></h2>
|
||
<table class="directive">
|
||
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables generation of <code>Expires</code>
|
||
headers</td></tr>
|
||
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExpiresActive On|Off</code></td></tr>
|
||
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ExpiresActive Off</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>Indexes</td></tr>
|
||
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
|
||
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_expires</td></tr>
|
||
</table>
|
||
<p>This directive enables or disables the generation of the
|
||
<code>Expires</code> and <code>Cache-Control</code> headers for
|
||
the document realm in question. (That is, if found in an
|
||
<code>.htaccess</code> file, for instance, it applies only to
|
||
documents generated from that directory.) If set to
|
||
<code>Off</code>, the headers will not be generated for any
|
||
document in the realm (unless overridden at a lower level, such as
|
||
an <code>.htaccess</code> file overriding a server config
|
||
file). If set to <code>On</code>, the headers will be added to
|
||
served documents according to the criteria defined by the
|
||
<code class="directive"><a href="#expiresbytype">ExpiresByType</a></code> and
|
||
<code class="directive"><a href="#expiresdefault">ExpiresDefault</a></code>
|
||
directives (<em>q.v.</em>).</p>
|
||
|
||
<p>Note that this directive does not guarantee that an
|
||
<code>Expires</code> or <code>Cache-Control</code> header will be
|
||
generated. If the criteria aren't met, no header will be sent, and
|
||
the effect will be as though this directive wasn't even
|
||
specified.</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="ExpiresByType" id="ExpiresByType">ExpiresByType</a> <a name="expiresbytype" id="expiresbytype">Directive</a></h2>
|
||
<table class="directive">
|
||
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Value of the <code>Expires</code> header configured
|
||
by MIME type</td></tr>
|
||
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExpiresByType <var>MIME-type</var>
|
||
<var><code>seconds</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>Indexes</td></tr>
|
||
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
|
||
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_expires</td></tr>
|
||
</table>
|
||
<p>This directive defines the value of the <code>Expires</code>
|
||
header and the <code>max-age</code> directive of the
|
||
<code>Cache-Control</code> header generated for documents of the
|
||
specified type (<em>e.g.</em>, <code>text/html</code>). The second
|
||
argument sets the number of seconds that will be added to a base
|
||
time to construct the expiration date. The <code>Cache-Control:
|
||
max-age</code> is calculated by subtracting the request time from
|
||
the expiration date and expressing the result in seconds.</p>
|
||
|
||
<p>The base time is either the last modification time of the
|
||
file, or the time of the client's access to the document. Which
|
||
should be used is specified by the
|
||
<code><var><code></var></code> field; <code>M</code>
|
||
means that the file's last modification time should be used as
|
||
the base time, and <code>A</code> means the client's access
|
||
time should be used.</p>
|
||
|
||
<p>The difference in effect is subtle. If <code>M</code> is used,
|
||
all current copies of the document in all caches will expire at
|
||
the same time, which can be good for something like a weekly
|
||
notice that's always found at the same URL. If <code>A</code> is
|
||
used, the date of expiration is different for each client; this
|
||
can be good for image files that don't change very often,
|
||
particularly for a set of related documents that all refer to
|
||
the same images (<em>i.e.</em>, the images will be accessed
|
||
repeatedly within a relatively short timespan).</p>
|
||
|
||
<div class="example"><h3>Example:</h3><pre class="prettyprint lang-config">
|
||
# enable expirations
|
||
ExpiresActive On
|
||
# expire GIF images after a month in the client's cache
|
||
ExpiresByType image/gif A2592000
|
||
# HTML documents are good for a week from the
|
||
# time they were changed
|
||
ExpiresByType text/html M604800
|
||
</pre>
|
||
</div>
|
||
|
||
<p>Note that this directive only has effect if
|
||
<code>ExpiresActive On</code> has been specified. It overrides,
|
||
for the specified MIME type <em>only</em>, any expiration date
|
||
set by the <code class="directive"><a href="#expiresdefault">ExpiresDefault</a></code>
|
||
directive.</p>
|
||
|
||
<p>You can also specify the expiration time calculation using
|
||
an <a href="#AltSyn">alternate syntax</a>, described earlier in
|
||
this document.</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="ExpiresDefault" id="ExpiresDefault">ExpiresDefault</a> <a name="expiresdefault" id="expiresdefault">Directive</a></h2>
|
||
<table class="directive">
|
||
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Default algorithm for calculating expiration time</td></tr>
|
||
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ExpiresDefault <var><code>seconds</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>Indexes</td></tr>
|
||
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
|
||
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_expires</td></tr>
|
||
</table>
|
||
<p>This directive sets the default algorithm for calculating the
|
||
expiration time for all documents in the affected realm. It can be
|
||
overridden on a type-by-type basis by the <code class="directive"><a href="#expiresbytype">ExpiresByType</a></code> directive. See the
|
||
description of that directive for details about the syntax of the
|
||
argument, and the <a href="#AltSyn">alternate syntax</a>
|
||
description as well.</p>
|
||
|
||
</div>
|
||
</div>
|
||
<div class="bottomlang">
|
||
<p><span>Available Languages: </span><a href="../en/mod/mod_expires.html" title="English"> en </a> |
|
||
<a href="../fr/mod/mod_expires.html" hreflang="fr" rel="alternate" title="Fran<61>ais"> fr </a> |
|
||
<a href="../ja/mod/mod_expires.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
|
||
<a href="../ko/mod/mod_expires.html" hreflang="ko" rel="alternate" title="Korean"> ko </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 again 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 Freenode, or sent to our <a href="http://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/trunk/mod/mod_expires.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 2012 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> |