<summary>
<note type="warning">
- This module is experimental. Documentation is still under development...
+ 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
+
+ <p><module>mod_cache</module> 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.
+ <module>mod_cache</module> requires the services of one or more storage
management modules. Two storage management modules are included in
the base Apache distribution:</p>
<dl>
<dt><module>mod_disk_cache</module></dt>
- <dd>implements a disk based storage manager for use with <module>mod_proxy</module></dd>
+ <dd>implements a disk based storage manager for use with
+ <module>mod_proxy</module></dd>
+
<dt><module>mod_mem_cache</module></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>
+ <dd>implements an in-memory based storage manager.
+ <module>mod_mem_cache</module> can be configured to operate in two
+ modes: caching open file descriptors or caching objects in heap storage.
+ <module>mod_mem_cache</module> is most useful when used to cache
+ locally generated content or to cache backend server content for
+ <module>mod_proxy</module> configured for <directive module="mod_proxy"
+ >ProxyPass</directive> (aka <dfn>reverse proxy</dfn>)</dd>
</dl>
+
<p>Content stored and retrived keyed to the URL. Content with
access protections is not cached.</p>
</summary>
</related>
</section>
-<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 />
-<IfModule mod_cache.c> <br />
-<br />
-#LoadModule disk_cache_module modules/mod_disk_cache.so <br />
- <IfModule mod_disk_cache.c> <br />
- CacheRoot c:/cacheroot <br />
- CacheSize 256 <br />
- CacheEnable disk / <br />
- CacheDirLevels 5 <br />
- CacheDirLength 3 <br />
- </IfModule> <br />
-<br />
- LoadModule mem_cache_module modules/mod_mem_cache.so <br />
- <IfModule mod_mem_cache.c> <br />
- MCacheEnable mem / <br />
- MCacheSize 4096 <br />
- MCacheMaxObjectCount 100 <br />
- MCacheMinObjectSize 1 <br />
- MCacheMaxObjectSize 2048 <br />
- </IfModule> <br />
-<br />
-</IfModule> <br />
-</example>
+<section id="sampleconf"><title>Sample Configuration</title>
+ <example><title>Sample httpd.conf</title>
+ #<br />
+ # Sample Cache Configuration<br />
+ #<br />
+ LoadModule cache_module modules/mod_cache.so<br />
+ <br />
+ <IfModule mod_cache.c><br />
+ <indent>
+ #LoadModule disk_cache_module modules/mod_disk_cache.so<br />
+ <IfModule mod_disk_cache.c><br />
+ <indent>
+ CacheRoot c:/cacheroot<br />
+ CacheSize 256<br />
+ CacheEnable disk /<br />
+ CacheDirLevels 5<br />
+ CacheDirLength 3<br />
+ </indent>
+ </IfModule> <br />
+ <br />
+ LoadModule mem_cache_module modules/mod_mem_cache.so<br />
+ <IfModule mod_mem_cache.c><br />
+ <indent>
+ MCacheEnable mem /<br />
+ MCacheSize 4096<br />
+ MCacheMaxObjectCount 100<br />
+ MCacheMinObjectSize 1<br />
+ MCacheMaxObjectSize 2048<br />
+ </indent>
+ </IfModule><br />
+ </indent>
+ </IfModule>
+ </example>
</section>
<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>
+<description>Enable caching specified URLs in a specified storage
+manager</description>
+<syntax>CacheEnable <var>cache_type</var> <var>url-string</var></syntax>
+<contextlist><context>server config</context><context>virtual host</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>
+ <module>mod_cache</module> to cache urls at or below
+ <var>url-string</var>. The cache store is specified with the
+ <var>cache_type</var> argument. <var>cache_type</var> <code>mem</code>
+ instructs <module>mod_cache</module> to use the in-memory cache storage
+ manager implemented by <module>mod_mem_cache</module>.
+ <var>cache_type</var> <code>disk</code> instructs
+ <module>mod_cache</module> to use the cache storage manager implemented
+ by <module>mod_disk_cache</module>.</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>
+<description>Disable caching of specified URLs by specified storage
+manager</description>
+<syntax>CacheDisable <var>cache_type</var> <var>url-string</var></syntax>
+<contextlist><context>server config</context><context>virtual host</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>
+ <module>mod_cache</module> to <em>not</em> cache urls at or below
+ <var>url-string</var>.</p>
-<example><title>Example</title>
- CacheDisable disk /local_files
-</example>
+ <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>
+<syntax>CacheMaxExpire <var>seconds</var></syntax>
<default>CacheMaxExpire 86400 (one day)</default>
-<contextlist><context>server config</context></contextlist>
+<contextlist><context>server config</context><context>virtual host</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>
+ <p>The maximum time in seconds to cache a document. The
+ <directive>CacheMaxExpire</directive> takes precedence over the
+ <code>Expires</code> field from the header.</p>
+
<example>
- CacheMaxExpire 604800
+ CacheMaxExpire 604800
</example>
</usage>
</directivesynopsis>
+
<directivesynopsis>
<name>CacheDefaultExpire</name>
-<syntax>CacheDefaultExpire <em>seconds</em></syntax>
+<description>The default time in seconds to cache a document</description>
+<syntax>CacheDefaultExpire <var>seconds</var></syntax>
<default>CacheDefaultExpire 3600 (one hour)</default>
-<contextlist><context>server config</context></contextlist>
+<contextlist><context>server config</context><context>virtual host</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>
+ an expiry date in the <code>Expires</code> field.</p>
+
<example>
- CacheDefaultExpire 86400
+ 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>
+<description>Ignore responses where there is no Last Modified
+Header</description>
+<syntax>CacheIgnoreNoLastMod On|Off</syntax>
+<default>CacheIgnoreNoLastMod Off</default>
+<contextlist><context>server config</context><context>virtual host</context>
+</contextlist>
<usage>
- <p>Ignore responses where there is no Last Modified Header</p>
+ <p>Ignore responses where there is no Last Modified Header.</p>
<example>
- CacheIgnoreNoLastMod
+ CacheIgnoreNoLastMod On
</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>
+<description>Ignore requests from the client for uncached
+content</description>
+<syntax>CacheIgnoreCacheControl On|Off</syntax>
+<default>CacheIgnoreCacheControl Off</default>
+<contextlist><context>server config</context><context>virtual host</context>
+</contextlist>
<usage>
<p>Ignore requests from the client for uncached content</p>
<example>
- CacheIgnoreNoLastMod
+ CacheIgnoreCacheControl On
</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>
+<description>The factor used to estimate the Expires date from the
+LastModified date</description>
+<syntax>CacheLastModifiedFactor <var>float</var></syntax>
<default>CacheLastModifiedFactor 0.1</default>
-<contextlist><context>server config</context></contextlist>
+<contextlist><context>server config</context><context>virtual host</context>
+</contextlist>
<usage>
<p>The factor used to estimate the Expires date from the LastModified date.</p>
<example>
- CacheLastModifiedFactor 0.5
+ CacheLastModifiedFactor 0.5
</example>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>CacheForceCompletion</name>
-<description>Percentage of download to arrive for the cache to force complete transfer</description>
-<syntax>CacheForceCompletion <em>Percentage</em></syntax>
+<description>Percentage of download to arrive for the cache to force
+complete transfer</description>
+<syntax>CacheForceCompletion <var>Percentage</var></syntax>
<default>CacheForceCompletion 60</default>
-<contextlist><context>server config</context></contextlist>
+<contextlist><context>server config</context><context>virtual host</context>
+</contextlist>
<usage>
- <p>Percentage of download to arrive for the cache to force complete transfert.</p>
+ <p>Percentage of download to arrive for the cache to force complete transfer.</p>
<example>
- CacheForceCompletion 80
+ CacheForceCompletion 80
</example>
-<note type="warning">
-This feature is currently <em>not</em> implemented.
-</note>
+
+ <note type="warning">
+ This feature is currently <em>not</em> implemented.
+ </note>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>CacheMaxStreamingBuffer</name>
-<description>Maximum amount of a streamed response to buffer in memory before declaring the response uncacheable</description>
-<syntax>CacheMaxStreamingBuffer <em>size_in_bytes</em></syntax>
+<description>Maximum amount of a streamed response to buffer in memory
+before declaring the response uncacheable</description>
+<syntax>CacheMaxStreamingBuffer <var>size_in_bytes</var></syntax>
<default>CacheMaxStreamingBuffer 0</default>
-<contextlist><context>server config</context></contextlist>
+<contextlist><context>server config</context><context>virtual host</context>
+</contextlist>
<usage>
-<p>Maximum number of bytes of a streamed response (i.e., a response where
-the entire content is not available all at once, such as a proxy or CGI
-response) to buffer before deciding if the response is cacheable. By
-default, a streamed response will <em>not</em> be cached unless it has a
-Content-Length header. The reason for this is to avoid using a large amount
-of memory to buffer a partial response that might end up being too large
-to fit in the cache anyway. To enable caching of streamed responses, use
-CacheMaxStreamingBuffer to specify the maximum amount of buffer space to use
-per request.</p>
-
-<p>Note: Using a nonzero value for CacheMaxStreamingBuffer will not delay the
-transmission of the response to the client. As soon as mod_cache copies a
-block of streamed content into a buffer, it sends the block on to the next
-output filter for delivery to the client.</p>
-
-<example>
-# Enable caching of streamed responses up to 64KB:<br />
-CacheMaxStreamingBuffer 65536
-</example>
+ <p>Maximum number of bytes of a streamed response (<em>i.e.</em>, a
+ response where the entire content is not available all at once, such
+ as a proxy or CGI response) to buffer before deciding if the response
+ is cacheable. By default, a streamed response will <em>not</em> be
+ cached unless it has a <code>Content-Length</code> header. The reason
+ for this is to avoid using a large amount of memory to buffer a partial
+ response that might end up being too large to fit in the cache anyway.
+ To enable caching of streamed responses, use <directive
+ >CacheMaxStreamingBuffer</directive> to specify the maximum amount of
+ buffer space to use per request.</p>
+
+ <note><title>Note:</title>
+ <p>Using a nonzero value for <directive
+ >CacheMaxStreamingBuffer</directive> will not delay the transmission
+ of the response to the client. As soon as <module>mod_cache</module>
+ copies a block of streamed content into a buffer, it sends the block
+ on to the next output filter for delivery to the client.</p>
+ </note>
+
+ <example>
+ # Enable caching of streamed responses up to 64KB:<br />
+ CacheMaxStreamingBuffer 65536
+ </example>
</usage>
</directivesynopsis>
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