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| <title>mod_cache - Apache HTTP Server</title> |
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| <p class="apache">Apache HTTP Server Version 2.3</p> |
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| <div id="page-content"> |
| <div id="preamble"><h1>Apache Module mod_cache</h1> |
| <div class="toplang"> |
| <p><span>Available Languages: </span><a href="../en/mod/mod_cache.html" title="English"> en </a> | |
| <a href="../ja/mod/mod_cache.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | |
| <a href="../ko/mod/mod_cache.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>Content cache keyed to URIs.</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 Identifier:</a></th><td>cache_module</td></tr> |
| <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_cache.c</td></tr></table> |
| <h3>Summary</h3> |
| |
| <div class="warning">This module should be used with care and |
| can be used to circumvent <code class="directive"><a href="../mod/mod_authz_host.html#allow">Allow</a></code> and <code class="directive"><a href="../mod/mod_authz_host.html#deny">Deny</a></code> directives. You |
| should not enable caching for any content to which you wish |
| to limit access by client host name, address or environment |
| variable.</div> |
| |
| <p><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> implements an <a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616</a> compliant HTTP |
| content cache that can be used to cache either local or proxied content. |
| <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> requires the services of one or more storage |
| management modules. Two storage management modules are included in |
| the base Apache distribution:</p> |
| <dl> |
| <dt><code class="module"><a href="../mod/mod_disk_cache.html">mod_disk_cache</a></code></dt> |
| <dd>implements a disk based storage manager.</dd> |
| |
| <dt><code class="module"><a href="../mod/mod_mem_cache.html">mod_mem_cache</a></code></dt> |
| <dd>implements a memory based storage manager. |
| <code class="module"><a href="../mod/mod_mem_cache.html">mod_mem_cache</a></code> can be configured to operate in two |
| modes: caching open file descriptors or caching objects in heap storage. |
| <code class="module"><a href="../mod/mod_mem_cache.html">mod_mem_cache</a></code> can be used to cache locally generated content |
| or to cache backend server content for <code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code> when |
| configured using <code class="directive"><a href="../mod/mod_proxy.html#proxypass">ProxyPass</a></code> |
| (aka <dfn>reverse proxy</dfn>)</dd> |
| </dl> |
| |
| <p>Content is stored in and retrieved from the cache using URI based keys. Content with |
| access protection is not cached.</p> |
| <p>Further details, discussion, and examples, are provided in the |
| <a href="../caching.html">Caching Guide</a>.</p> |
| </div> |
| <div id="quickview"><h3 class="directives">Directives</h3> |
| <ul id="toc"> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cachedefaultexpire">CacheDefaultExpire</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cachedisable">CacheDisable</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cacheenable">CacheEnable</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cacheignorecachecontrol">CacheIgnoreCacheControl</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cacheignoreheaders">CacheIgnoreHeaders</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cacheignorenolastmod">CacheIgnoreNoLastMod</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cacheignorequerystring">CacheIgnoreQueryString</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cachelastmodifiedfactor">CacheLastModifiedFactor</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cachemaxexpire">CacheMaxExpire</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cacheminexpire">CacheMinExpire</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cachestorenostore">CacheStoreNoStore</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#cachestoreprivate">CacheStorePrivate</a></li> |
| </ul> |
| <h3>Topics</h3> |
| <ul id="topics"> |
| <li><img alt="" src="../images/down.gif" /> <a href="#related">Related Modules and Directives</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#sampleconf">Sample Configuration</a></li> |
| </ul><h3>See also</h3> |
| <ul class="seealso"> |
| <li><a href="../caching.html">Caching Guide</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="related" id="related">Related Modules and Directives</a></h2> |
| <table class="related"><tr><th>Related Modules</th><th>Related Directives</th></tr><tr><td><ul><li><code class="module"><a href="../mod/mod_disk_cache.html">mod_disk_cache</a></code></li><li><code class="module"><a href="../mod/mod_mem_cache.html">mod_mem_cache</a></code></li></ul></td><td><ul><li><code class="directive"><a href="../mod/mod_disk_cache.html#cacheroot">CacheRoot</a></code></li><li><code class="directive"><a href="../mod/mod_disk_cache.html#cachedirlevels">CacheDirLevels</a></code></li><li><code class="directive"><a href="../mod/mod_disk_cache.html#cachedirlength">CacheDirLength</a></code></li><li><code class="directive"><a href="../mod/mod_disk_cache.html#cacheminfilesize">CacheMinFileSize</a></code></li><li><code class="directive"><a href="../mod/mod_disk_cache.html#cachemaxfilesize">CacheMaxFileSize</a></code></li><li><code class="directive"><a href="../mod/mod_mem_cache.html#mcachesize">MCacheSize</a></code></li><li><code class="directive"><a href="../mod/mod_mem_cache.html#mcachemaxobjectcount">MCacheMaxObjectCount</a></code></li><li><code class="directive"><a href="../mod/mod_mem_cache.html#mcacheminobjectsize">MCacheMinObjectSize</a></code></li><li><code class="directive"><a href="../mod/mod_mem_cache.html#mcachemaxobjectsize">MCacheMaxObjectSize</a></code></li><li><code class="directive"><a href="../mod/mod_mem_cache.html#mcacheremovalalgorithm">MCacheRemovalAlgorithm</a></code></li><li><code class="directive"><a href="../mod/mod_mem_cache.html#mcachemaxstreamingbuffer">MCacheMaxStreamingBuffer</a></code></li></ul></td></tr></table> |
| </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="section"> |
| <h2><a name="sampleconf" id="sampleconf">Sample Configuration</a></h2> |
| <div class="example"><h3>Sample httpd.conf</h3><p><code> |
| #<br /> |
| # Sample Cache Configuration<br /> |
| #<br /> |
| LoadModule cache_module modules/mod_cache.so<br /> |
| <br /> |
| <IfModule mod_cache.c><br /> |
| <span class="indent"> |
| #LoadModule disk_cache_module modules/mod_disk_cache.so<br /> |
| # If you want to use mod_disk_cache instead of mod_mem_cache,<br /> |
| # uncomment the line above and comment out the LoadModule line below.<br /> |
| <IfModule mod_disk_cache.c><br /> |
| <span class="indent"> |
| CacheRoot c:/cacheroot<br /> |
| CacheEnable disk /<br /> |
| CacheDirLevels 5<br /> |
| CacheDirLength 3<br /> |
| </span> |
| </IfModule> <br /> |
| <br /> |
| LoadModule mem_cache_module modules/mod_mem_cache.so<br /> |
| <IfModule mod_mem_cache.c><br /> |
| <span class="indent"> |
| CacheEnable mem /<br /> |
| MCacheSize 4096<br /> |
| MCacheMaxObjectCount 100<br /> |
| MCacheMinObjectSize 1<br /> |
| MCacheMaxObjectSize 2048<br /> |
| </span> |
| </IfModule><br /> |
| <br /> |
| # When acting as a proxy, don't cache the list of security updates<br /> |
| CacheDisable http://security.update.server/update-list/<br /> |
| </span> |
| </IfModule> |
| </code></p></div> |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheDefaultExpire" id="CacheDefaultExpire">CacheDefaultExpire</a> <a name="cachedefaultexpire" id="cachedefaultexpire">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The default duration to cache a document when no expiry date is specified.</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheDefaultExpire <var>seconds</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheDefaultExpire 3600 (one hour)</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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>The <code class="directive">CacheDefaultExpire</code> directive specifies a default time, |
| in seconds, to cache a document if neither an expiry date nor last-modified date are provided |
| with the document. The value specified with the <code class="directive">CacheMaxExpire</code> |
| directive does <em>not</em> override this setting.</p> |
| |
| <div class="example"><p><code> |
| CacheDefaultExpire 86400 |
| </code></p></div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheDisable" id="CacheDisable">CacheDisable</a> <a name="cachedisable" id="cachedisable">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Disable caching of specified URLs</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheDisable <var> url-string</var></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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>The <code class="directive">CacheDisable</code> directive instructs |
| <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> to <em>not</em> cache urls at or below |
| <var>url-string</var>.</p> |
| |
| <div class="example"><h3>Example</h3><p><code> |
| CacheDisable /local_files |
| </code></p></div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheEnable" id="CacheEnable">CacheEnable</a> <a name="cacheenable" id="cacheenable">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable caching of specified URLs using a specified storage |
| manager</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheEnable <var>cache_type</var> <var>url-string</var></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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>The <code class="directive">CacheEnable</code> directive instructs |
| <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> to cache urls at or below |
| <var>url-string</var>. The cache storage manager is specified with the |
| <var>cache_type</var> argument. <var>cache_type</var> <code> mem</code> |
| instructs <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> to use the memory based storage |
| manager implemented by <code class="module"><a href="../mod/mod_mem_cache.html">mod_mem_cache</a></code>. |
| <var>cache_type</var> <code>disk</code> instructs |
| <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> to use the disk based storage manager |
| implemented by <code class="module"><a href="../mod/mod_disk_cache.html">mod_disk_cache</a></code>. |
| <var>cache_type</var> <code>fd</code> instructs |
| <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> to use the file descriptor cache implemented |
| by <code class="module"><a href="../mod/mod_mem_cache.html">mod_mem_cache</a></code>.</p> |
| <p>In the event that the URL space overlaps between different |
| <code class="directive">CacheEnable</code> directives (as in the example below), |
| each possible storage manager will be run until the first one that |
| actually processes the request. The order in which the storage managers are |
| run is determined by the order of the <code class="directive">CacheEnable</code> |
| directives in the configuration file.</p> |
| |
| <div class="example"><p><code> |
| CacheEnable mem /manual<br /> |
| CacheEnable fd /images<br /> |
| CacheEnable disk /<br /> |
| </code></p></div> |
| |
| <p>When acting as a forward proxy server, <var>url-string</var> can |
| also be used to specify remote sites and proxy protocols which |
| caching should be enabled for.</p> |
| |
| <div class="example"><p><code> |
| # Cache proxied url's<br /> |
| CacheEnable disk /<br /><br /> |
| # Cache FTP-proxied url's<br /> |
| CacheEnable disk ftp://<br /><br /> |
| # Cache content from www.apache.org<br /> |
| CacheEnable disk http://www.apache.org/<br /> |
| </code></p></div> |
| |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheIgnoreCacheControl" id="CacheIgnoreCacheControl">CacheIgnoreCacheControl</a> <a name="cacheignorecachecontrol" id="cacheignorecachecontrol">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Ignore request to not serve cached content to client</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheIgnoreCacheControl On|Off</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheIgnoreCacheControl 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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>Ordinarily, requests containing a Cache-Control: no-cache or |
| Pragma: no-cache header value will not be served from the cache. The |
| <code class="directive">CacheIgnoreCacheControl</code> directive allows this |
| behavior to be overridden. <code class="directive">CacheIgnoreCacheControl</code> |
| On tells the server to attempt to serve the resource from the cache even |
| if the request contains no-cache header values. Resources requiring |
| authorization will <em>never</em> be cached.</p> |
| |
| <div class="example"><p><code> |
| CacheIgnoreCacheControl On |
| </code></p></div> |
| |
| <div class="warning"><h3>Warning:</h3> |
| This directive will allow serving from the cache even if the client has |
| requested that the document not be served from the cache. This might |
| result in stale content being served. |
| </div> |
| |
| <h3>See also</h3> |
| <ul> |
| <li><code class="directive"><a href="#cachestoreprivate">CacheStorePrivate</a></code></li> |
| <li><code class="directive"><a href="#cachestorenostore">CacheStoreNoStore</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="CacheIgnoreHeaders" id="CacheIgnoreHeaders">CacheIgnoreHeaders</a> <a name="cacheignoreheaders" id="cacheignoreheaders">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Do not store the given HTTP header(s) in the cache. |
| </td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheIgnoreHeaders <var>header-string</var> [<var>header-string</var>] ...</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheIgnoreHeaders None</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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>According to RFC 2616, hop-by-hop HTTP headers are not stored in |
| the cache. The following HTTP headers are hop-by-hop headers and thus |
| do not get stored in the cache in <em>any</em> case regardless of the |
| setting of <code class="directive">CacheIgnoreHeaders</code>:</p> |
| |
| <ul> |
| <li><code>Connection</code></li> |
| <li><code>Keep-Alive</code></li> |
| <li><code>Proxy-Authenticate</code></li> |
| <li><code>Proxy-Authorization</code></li> |
| <li><code>TE</code></li> |
| <li><code>Trailers</code></li> |
| <li><code>Transfer-Encoding</code></li> |
| <li><code>Upgrade</code></li> |
| </ul> |
| |
| <p><code class="directive">CacheIgnoreHeaders</code> specifies additional HTTP |
| headers that should not to be stored in the cache. For example, it makes |
| sense in some cases to prevent cookies from being stored in the cache.</p> |
| |
| <p><code class="directive">CacheIgnoreHeaders</code> takes a space separated list |
| of HTTP headers that should not be stored in the cache. If only hop-by-hop |
| headers not should be stored in the cache (the RFC 2616 compliant |
| behaviour), <code class="directive">CacheIgnoreHeaders</code> can be set to |
| <code>None</code>.</p> |
| |
| <div class="example"><h3>Example 1</h3><p><code> |
| CacheIgnoreHeaders Set-Cookie |
| </code></p></div> |
| |
| <div class="example"><h3>Example 2</h3><p><code> |
| CacheIgnoreHeaders None |
| </code></p></div> |
| |
| <div class="warning"><h3>Warning:</h3> |
| If headers like <code>Expires</code> which are needed for proper cache |
| management are not stored due to a |
| <code class="directive">CacheIgnoreHeaders</code> setting, the behaviour of |
| mod_cache is undefined. |
| </div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheIgnoreNoLastMod" id="CacheIgnoreNoLastMod">CacheIgnoreNoLastMod</a> <a name="cacheignorenolastmod" id="cacheignorenolastmod">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Ignore the fact that a response has no Last Modified |
| header.</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheIgnoreNoLastMod On|Off</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheIgnoreNoLastMod 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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>Ordinarily, documents without a last-modified date are not cached. |
| Under some circumstances the last-modified date is removed (during |
| <code class="module"><a href="../mod/mod_include.html">mod_include</a></code> processing for example) or not provided |
| at all. The <code class="directive">CacheIgnoreNoLastMod</code> directive |
| provides a way to specify that documents without last-modified dates |
| should be considered for caching, even without a last-modified date. |
| If neither a last-modified date nor an expiry date are provided with |
| the document then the value specified by the |
| <code class="directive">CacheDefaultExpire</code> directive will be used to |
| generate an expiration date.</p> |
| |
| <div class="example"><p><code> |
| CacheIgnoreNoLastMod On |
| </code></p></div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheIgnoreQueryString" id="CacheIgnoreQueryString">CacheIgnoreQueryString</a> <a name="cacheignorequerystring" id="cacheignorequerystring">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Ignore query string when caching</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheIgnoreQueryString On|Off</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheIgnoreQueryString 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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>Ordinarily, requests with query string parameters are cached separately |
| for each unique query string. This is according to RFC 2616/13.9 done only |
| if an expiration time is specified. The |
| <code class="directive">CacheIgnoreQueryString</code> directive tells the cache to |
| cache requests even if no expiration time is specified, and to reply with |
| a cached reply even if the query string differs. From a caching point of |
| view the request is treated as if having no query string when this |
| directive is enabled.</p> |
| |
| <div class="example"><p><code> |
| CacheIgnoreQueryString On |
| </code></p></div> |
| |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheLastModifiedFactor" id="CacheLastModifiedFactor">CacheLastModifiedFactor</a> <a name="cachelastmodifiedfactor" id="cachelastmodifiedfactor">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The factor used to compute an expiry date based on the |
| LastModified date.</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheLastModifiedFactor <var>float</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheLastModifiedFactor 0.1</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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>In the event that a document does not provide an expiry date but does |
| provide a last-modified date, an expiry date can be calculated based on |
| the time since the document was last modified. The |
| <code class="directive">CacheLastModifiedFactor</code> directive specifies a |
| <var>factor</var> to be used in the generation of this expiry date |
| according to the following formula: |
| |
| <code>expiry-period = time-since-last-modified-date * <var>factor</var> |
| expiry-date = current-date + expiry-period</code> |
| |
| For example, if the document was last modified 10 hours ago, and |
| <var>factor</var> is 0.1 then the expiry-period will be set to |
| 10*0.1 = 1 hour. If the current time was 3:00pm then the computed |
| expiry-date would be 3:00pm + 1hour = 4:00pm. |
| |
| If the expiry-period would be longer than that set by |
| <code class="directive">CacheMaxExpire</code>, then the latter takes |
| precedence.</p> |
| |
| <div class="example"><p><code> |
| CacheLastModifiedFactor 0.5 |
| </code></p></div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheMaxExpire" id="CacheMaxExpire">CacheMaxExpire</a> <a name="cachemaxexpire" id="cachemaxexpire">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The maximum time in seconds to cache a document</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheMaxExpire <var>seconds</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheMaxExpire 86400 (one day)</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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>The <code class="directive">CacheMaxExpire</code> directive specifies the maximum number of |
| seconds for which cachable HTTP documents will be retained without checking the origin |
| server. Thus, documents will be out of date at most this number of seconds. This maximum |
| value is enforced even if an expiry date was supplied with the document.</p> |
| |
| <div class="example"><p><code> |
| CacheMaxExpire 604800 |
| </code></p></div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheMinExpire" id="CacheMinExpire">CacheMinExpire</a> <a name="cacheminexpire" id="cacheminexpire">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The minimum time in seconds to cache a document</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheMinExpire <var>seconds</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheMinExpire 0</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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>The <code class="directive">CacheMinExpire</code> directive specifies the minimum number of |
| seconds for which cachable HTTP documents will be retained without checking the origin |
| server. This is only used if no valid expire time was supplied with the document.</p> |
| |
| |
| <div class="example"><p><code> |
| CacheMinExpire 3600 |
| </code></p></div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="CacheStoreNoStore" id="CacheStoreNoStore">CacheStoreNoStore</a> <a name="cachestorenostore" id="cachestorenostore">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Attempt to cache requests or responses that have been marked as no-store.</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheStoreNoStore On|Off</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheStoreNoStore 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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>Ordinarily, requests or responses with Cache-Control: no-store header |
| values will not be stored in the cache. The |
| <code class="directive">CacheStoreNoCache</code> directive allows this |
| behavior to be overridden. <code class="directive">CacheStoreNoCache</code> On |
| tells the server to attempt to cache the resource even if it contains |
| no-store header values. Resources requiring authorization will |
| <em>never</em> be cached.</p> |
| |
| <div class="example"><p><code> |
| CacheStoreNoStore On |
| </code></p></div> |
| |
| <div class="warning"><h3>Warning:</h3> |
| As described in RFC 2616, the no-store directive is intended to |
| "prevent the inadvertent release or retention of sensitive information |
| (for example, on backup tapes)." Enabling this option could store |
| sensitive information in the cache. You are hereby warned. |
| </div> |
| |
| <h3>See also</h3> |
| <ul> |
| <li><code class="directive"><a href="#cacheignorecachecontrol">CacheIgnoreCacheControl</a></code></li> |
| <li><code class="directive"><a href="#cachestoreprivate">CacheStorePrivate</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="CacheStorePrivate" id="CacheStorePrivate">CacheStorePrivate</a> <a name="cachestoreprivate" id="cachestoreprivate">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Attempt to cache responses that the server has marked as private</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CacheStorePrivate On|Off</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>CacheStorePrivate 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>Extension</td></tr> |
| <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_cache</td></tr> |
| </table> |
| <p>Ordinarily, responses with Cache-Control: private header values will not |
| be stored in the cache. The <code class="directive">CacheStorePrivate</code> |
| directive allows this behavior to be overridden. |
| <code class="directive">CacheStorePrivate</code> On |
| tells the server to attempt to cache the resource even if it contains |
| private header values. Resources requiring authorization will |
| <em>never</em> be cached.</p> |
| |
| <div class="example"><p><code> |
| CacheStorePrivate On |
| </code></p></div> |
| |
| <div class="warning"><h3>Warning:</h3> |
| This directive will allow caching even if the upstream server has |
| requested that the resource not be cached. This directive is only |
| ideal for a 'private' cache. |
| </div> |
| |
| <h3>See also</h3> |
| <ul> |
| <li><code class="directive"><a href="#cacheignorecachecontrol">CacheIgnoreCacheControl</a></code></li> |
| <li><code class="directive"><a href="#cachestorenostore">CacheStoreNoStore</a></code></li> |
| </ul> |
| </div> |
| </div> |
| <div class="bottomlang"> |
| <p><span>Available Languages: </span><a href="../en/mod/mod_cache.html" title="English"> en </a> | |
| <a href="../ja/mod/mod_cache.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | |
| <a href="../ko/mod/mod_cache.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p> |
| </div><div id="footer"> |
| <p class="apache">Copyright 2006 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="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div> |
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