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<modulesynopsis metafile="mod_cache_socache.xml.meta">

<name>mod_cache_socache</name>

<description>Shared object cache (socache) based storage module for the

HTTP caching filter.</description>

<status>Extension</status>

<sourcefile>mod_cache_socache.c</sourcefile>

<identifier>cache_socache_module</identifier>

<summary>

<p><module>mod_cache_socache</module> implements a shared object cache

(socache) based storage manager for <module>mod_cache</module>.</p>

<p>The headers and bodies of cached responses are combined, and stored

underneath a single key in the shared object cache. A

<a href="/socache.html">number of implementations</a> of shared object

caches are available to choose from.</p>

<p>Multiple content negotiated responses can be stored concurrently,

however the caching of partial content is not yet supported by this

module.</p>

<highlight language="config">

# Turn on caching

CacheSocache shmcb

CacheSocacheMaxSize 102400

&lt;Location "/foo"&gt;

CacheEnable socache

&lt;/Location&gt;

# Fall back to the disk cache

CacheSocache shmcb

CacheSocacheMaxSize 102400

&lt;Location "/foo"&gt;

CacheEnable socache

CacheEnable disk

&lt;/Location&gt;

</highlight>

<note><title>Note:</title>

<p><module>mod_cache_socache</module> requires the services of

<module>mod_cache</module>, which must be loaded before

mod_cache_socache.</p>

</note>

</summary>

<seealso><module>mod_cache</module></seealso>

<seealso><module>mod_cache_disk</module></seealso>

<seealso><a href="/caching.html">Caching Guide</a></seealso>

<directivesynopsis>

<name>CacheSocache</name>

<description>The shared object cache implementation to use</description>

<syntax>CacheSocache <var>type[:args]</var></syntax>

<contextlist><context>server config</context><context>virtual host</context>

</contextlist>

<compatibility>Available in Apache 2.4.5 and later</compatibility>

<usage>

<p>The <directive>CacheSocache</directive> directive defines the name of

the shared object cache implementation to use, followed by optional

arguments for that implementation. A <a href="/socache.html">number of

implementations</a> of shared object caches are available to choose

from.</p>

<highlight language="config">

CacheSocache shmcb

</highlight>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheSocacheMaxTime</name>

<description>The maximum time (in seconds) for a document to be placed in the

cache</description>

<syntax>CacheSocacheMaxTime <var>seconds</var></syntax>

<default>CacheSocacheMaxTime 86400</default>

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

<context>virtual host</context>

<context>directory</context>

<context>.htaccess</context>

</contextlist>

<compatibility>Available in Apache 2.4.5 and later</compatibility>

<usage>

<p>The <directive>CacheSocacheMaxTime</directive> directive sets the

maximum freshness lifetime, in seconds, for a document to be stored in

the cache. This value overrides the freshness lifetime defined for the

document by the HTTP protocol.</p>

<highlight language="config">

CacheSocacheMaxTime 86400

</highlight>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheSocacheMinTime</name>

<description>The minimum time (in seconds) for a document to be placed in the

cache</description>

<syntax>CacheSocacheMinTime <var>seconds</var></syntax>

<default>CacheSocacheMinTime 600</default>

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

<context>virtual host</context>

<context>directory</context>

<context>.htaccess</context>

</contextlist>

<compatibility>Available in Apache 2.4.5 and later</compatibility>

<usage>

<p>The <directive>CacheSocacheMinTime</directive> directive sets the

amount of seconds beyond the freshness lifetime of the response that the

response should be cached for in the shared object cache. If a response is

only stored for its freshness lifetime, there will be no opportunity to

revalidate the response to make it fresh again.</p>

<highlight language="config">

CacheSocacheMinTime 600

</highlight>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheSocacheMaxSize</name>

<description>The maximum size (in bytes) of an entry to be placed in the

cache</description>

<syntax>CacheSocacheMaxSize <var>bytes</var></syntax>

<default>CacheSocacheMaxSize 102400</default>

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

<context>virtual host</context>

<context>directory</context>

<context>.htaccess</context>

</contextlist>

<compatibility>Available in Apache 2.4.5 and later</compatibility>

<usage>

<p>The <directive>CacheSocacheMaxSize</directive> directive sets the

maximum size, in bytes, for the combined headers and body of a document

to be considered for storage in the cache. The larger the headers that

are stored alongside the body, the smaller the body may be.</p>

<p>The <module>mod_cache_socache</module> module will only attempt to

cache responses that have an explicit content length, or that are small

enough to be written in one pass. This is done to allow the

<module>mod_cache_disk</module> module to have an opportunity to cache

responses larger than those cacheable within

<module>mod_cache_socache</module>.</p>

<highlight language="config">

CacheSocacheMaxSize 102400

</highlight>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheSocacheReadSize</name>

<description>The minimum size (in bytes) of the document to read and be cached

before sending the data downstream</description>

<syntax>CacheSocacheReadSize <var>bytes</var></syntax>

<default>CacheSocacheReadSize 0</default>

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

<context>virtual host</context>

<context>directory</context>

<context>.htaccess</context>

</contextlist>

<compatibility>Available in Apache 2.4.5 and later</compatibility>

<usage>

<p>The <directive>CacheSocacheReadSize</directive> directive sets the

minimum amount of data, in bytes, to be read from the backend before the

data is sent to the client. The default of zero causes all data read of

any size to be passed downstream to the client immediately as it arrives.

Setting this to a higher value causes the disk cache to buffer at least

this amount before sending the result to the client. This can improve

performance when caching content from a slow reverse proxy.</p>

<p>This directive only takes effect when the data is being saved to the

cache, as opposed to data being served from the cache.</p>

<highlight language="config">

CacheReadSize 102400

</highlight>

</usage>

</directivesynopsis>

<directivesynopsis>

<name>CacheSocacheReadTime</name>

<description>The minimum time (in milliseconds) that should elapse while reading

before data is sent downstream</description>

<syntax>CacheSocacheReadTime <var>milliseconds</var></syntax>

<default>CacheSocacheReadTime 0</default>

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

<context>virtual host</context>

<context>directory</context>

<context>.htaccess</context>

</contextlist>

<compatibility>Available in Apache 2.4.5 and later</compatibility>

<usage>

<p>The <directive>CacheSocacheReadTime</directive> directive sets the minimum amount

of elapsed time that should pass before making an attempt to send data

downstream to the client. During the time period, data will be buffered

before sending the result to the client. This can improve performance when

caching content from a reverse proxy.</p>

<p>The default of zero disables this option.</p>

<p>This directive only takes effect when the data is being saved to the

cache, as opposed to data being served from the cache. It is recommended

that this option be used alongside the

<directive module="mod_cache_socache">CacheSocacheReadSize</directive> directive

to ensure that the server does not buffer excessively should data arrive faster

than expected.</p>

<highlight language="config">

CacheSocacheReadTime 1000

</highlight>

</usage>

</directivesynopsis>

</modulesynopsis>