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<modulesynopsis>

<name>mod_cache</name>

<description>Content cache keyed to URIs.</description>

<status>Experimental</status>

<sourcefile>mod_cache.c</sourcefile>

<identifier>cache_module</identifier>

<summary>

<note type="warning">

This module is experimental. Documentation is still under development...

</note>

<p>mod_cache implements an RFC 2616 compliant HTTP content

cache that can be used to cache either local or proxied content.

mod_cache requires the services of one or more storage

management modules. Two storage management modules are included in

the base Apache distribution:</p>

<dl>

<dt><em><module>mod_disk_cache</module></em></dt>

<dd>implements a disk based storage manager for use with <module>mod_proxy</module></dd>

<dt><em><module>mod_mem_cache</module></em></dt>

<dd>implements an in-memory based storage manager. mod_mem_cache

can be configured to operate in two modes: caching open file

descriptors or caching objects in heap storage. <em><module>mod_mem_cache</module></em>

is most useful when used to cache locally generated content or to cache

backend server content for mod_proxy configured for ProxyPass (aka <em>reverse proxy</em>)</dd>

</dl>

<p>Content stored and retrived keyed to the URL. Content with

access protections is not cached.</p>

<related>

<modulelist>

<module>mod_disk_cache</module>

<module>mod_mem_cache</module>

</modulelist>

<directivelist>

<directive module="mod_disk_cache">CacheRoot</directive>

<directive module="mod_disk_cache">CacheSize</directive>

<directive module="mod_disk_cache">CacheGcInterval</directive>

<directive module="mod_disk_cache">CacheDirLevels</directive>

<directive module="mod_disk_cache">CacheDirLength</directive>

<directive module="mod_disk_cache">CacheExpiryCheck</directive>

<directive module="mod_disk_cache">CacheMinFileSize</directive>

<directive module="mod_disk_cache">CacheMaxFileSize</directive>

<directive module="mod_disk_cache">CacheTimeMargin</directive>

<directive module="mod_disk_cache">CacheGcDaily</directive>

<directive module="mod_disk_cache">CacheGcUnused</directive>

<directive module="mod_disk_cache">CacheGcClean</directive>

<directive module="mod_disk_cache">CacheGcMemUsage</directive>

<directive module="mod_mem_cache">MCacheSize</directive>

<directive module="mod_mem_cache">MCacheMaxObjectCount</directive>

<directive module="mod_mem_cache">MCacheMinObjectSize</directive>

<directive module="mod_mem_cache">MCacheMaxObjectSize</directive>

<directive module="mod_mem_cache">MCacheRemovalAlgorithm</directive>

</directivelist>

</related>

</summary>

<section><title>Sample Configuration</title>

<example><title>Sample httpd.conf</title>

# <br />

# Sample Cache Configuration <br />

# <br />

LoadModule cache_module modules/mod_cache.so <br />

&lt;IfModule mod_cache.c&gt;<br />

CacheOn On<br />

<p />

#LoadModule disk_cache_module modules/mod_disk_cache.so <br />

&lt;IfModule mod_disk_cache.c&gt; <br />

CacheRoot c:/cacheroot <br />

CacheSize 256 <br />

CacheEnable disk / <br />

CacheDirLevels 5 <br />

CacheDirLength 3 <br />

&lt;/IfModule&gt; <br />

<p />

LoadModule mem_cache_module modules/mod_mem_cache.so <br />

&lt;IfModule mod_mem_cache.c&gt; <br />

MCacheEnable mem / <br />

MCacheSize 4096 <br />

MCacheMaxObjectCount 100 <br />

MCacheMinObjectSize 1 <br />

MCacheMaxObjectSize 2048 <br />

&lt;/IfModule&gt; <br />

<p />

&lt;/IfModule&gt; <br />

</example>

</section>

<directivesynopsis>

<name>CacheOn</name>

<description></description>

<syntax>CacheOn</syntax>

<contextlist><context>server config</context></contextlist>

<usage>

<p>

</p>

<example>

CacheOn

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheEnable</name>

<description>Enable caching specified URLs in a specified storage manager</description>

<syntax>CacheEnable <em>cache_type </em><em> url-string</em></syntax>

<contextlist><context>server config</context></contextlist>

<usage>

<p>The <directive>CacheEnable</directive> directive instructs

mod_cache to cache urls at or below <em>url-string</em>.

The cache store is specified with the <em>cache_type</em> argument.

<em>cache_type </em> <em> mem</em> instructs mod_cache to use the

in-memory cache storage manager implemented by <em>mod_mem_cache</em>.

<em>cache_type </em> <em> disk</em> instructs mod_cache to use the

cache storage manager implemented by <em>mod_disk_cache </em>. </p>

<example>

CacheEnable disk / <br />

CacheEnable mem /manual <br />

CacheEnable fd /images <br />

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheDisable</name>

<description>Disable caching of specified URLs by specified storage manager</description>

<syntax>CacheDisable <em>cache_type </em> <em> url-string</em></syntax>

<contextlist><context>server config</context></contextlist>

<usage>

<p>The <directive>CacheDisable</directive> directive instructs

mod_cache to <em>not</em> cache urls at or above <em>url-string</em>.</p>

<example><title>Example</title>

CacheDisable disk /local_files

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheMaxExpire</name>

<description>The maximum time in seconds to cache a document</description>

<syntax>CacheMaxExpire <em>seconds</em></syntax>

<default>CacheMaxExpire 86400 <em>(one day)</em></default>

<contextlist><context>server config</context></contextlist>

<usage>

<p>The maximum time in seconds to cache a document. The <directive>CacheMaxExpire</directive>

takes precedence over the <em>Expire</em> field from the header.</p>

<example>

CacheMaxExpire 604800

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheDefaultExpire</name>

<syntax>CacheDefaultExpire <em>seconds</em></syntax>

<default>CacheDefaultExpire 3600 <em>(one hour)</em></default>

<contextlist><context>server config</context></contextlist>

<usage>

<p>The default time in seconds to cache a document if the page does not have

an expiry date in the <em>Expires</em> field.</p>

<example>

CacheDefaultExpire 86400

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheIgnoreNoLastMod</name>

<description>Ignore responses where there is no Last Modified Header</description>

<syntax>CacheIgnoreNoLastMod</syntax>

<contextlist><context>server config</context></contextlist>

<usage>

<p>Ignore responses where there is no Last Modified Header</p>

<example>

CacheIgnoreNoLastMod

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheIgnoreCacheControl</name>

<description>Ignore requests from the client for uncached content</description>

<syntax>CacheIgnoreCacheControl</syntax>

<contextlist><context>server config</context></contextlist>

<usage>

<p>Ignore requests from the client for uncached content</p>

<example>

CacheIgnoreNoLastMod

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheLastModifiedFactor</name>

<description>The factor used to estimate the Expires date from the LastModified date</description>

<syntax>CacheLastModifiedFactor <em>float</em></syntax>

<default>CacheLastModifiedFactor 0.1</default>

<contextlist><context>server config</context></contextlist>

<usage>

<p>The factor used to estimate the Expires date from the LastModified date.</p>

<example>

CacheLastModifiedFactor

</example>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheForceCompletion</name>

<description>Percentage of download to arrive for the cache to force complete transfert</description>

<syntax>CacheLastModifiedFactor <em>Percentage</em></syntax>

<default>CacheLastModifiedFactor 60</default>

<contextlist><context>server config</context></contextlist>

<usage>

<p>Percentage of download to arrive for the cache to force complete transfert.</p>

<example>

CacheForceCompletion

</example>

<note type="warning">

This feature is currently <em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheForceCompletion</name>

<description>Percentage of download to arrive for the cache to force complete transfert</description>

<syntax>CacheLastModifiedFactor <em>Percentage</em></syntax>

<default>CacheLastModifiedFactor 60</default>

<contextlist><context>server config</context></contextlist>

<usage>

<p>Percentage of download to arrive for the cache to force complete transfert.</p>

<example>

CacheForceCompletion

</example>

<note type="warning">

This feature is currently <em>not</em> implemented.

</note>

</usage>

</directivesynopsis>

</modulesynopsis>