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@@ -482,6 +482,219 @@ $cache = Zend_Cache::factory('Core', 'Zend_Cache_Backend_ZendServer_Disk',
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There is no option for this backend.
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</para>
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</sect2>
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+
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+ <sect2 id="zend.cache.backends.static">
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+ <title>Zend_Cache_Backend_Static</title>
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+ <para>
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+ This backend works in concert with <classname>
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+ Zend_Cache_Frontend_Capture</classname> (the two must be used
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+ together) to save the output from requests as static files. This
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+ means the static files are served directly on subsequent requests
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+ without any involvement of PHP or the Zend Framework at all.
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+ </para>
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+ <para>
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+ The benefits of this cache include a large throughput increase since
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+ all subsequent requests return the static file and don't need any
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+ dynamic processing. Of course this also has some disadvantages. The
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+ only way to retry the dynamic request is to purge the cached file
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+ from elsewhere in the application (or via a cronjob if timed). It
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+ is also restricted to single-server applications where only one
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+ filesystem is used. Nevertheless, it can be a powerful means of
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+ getting more performance without incurring the cost of a proxy on
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+ single machines.
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+ </para>
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+ <para>
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+ Before describing its options, you should note this needs some
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+ changes to the default .htaccess file in order for requests to be
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+ directed to the static files if they exist. Here's an example of
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+ a simple application caching some content, including two specific
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+ feeds which need additional treatment to serve a correct
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+ Content-Type header:
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+ </para>
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+ <programlisting language="text"><![CDATA[
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+AddType application/rss+xml .xml
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+AddType application/atom+xml .xml
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+
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+RewriteEngine On
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+
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+RewriteCond %{REQUEST_URI} feed/rss$
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+RewriteCond %{DOCUMENT_ROOT}/cached/%{REQUEST_URI}.xml -f
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+RewriteRule .* cached/%{REQUEST_URI}.xml [L,T=application/rss+xml]
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+
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+RewriteCond %{REQUEST_URI} feed/atom$
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+RewriteCond %{DOCUMENT_ROOT}/cached/%{REQUEST_URI}.xml -f
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+RewriteRule .* cached/%{REQUEST_URI}.xml [L,T=application/atom+xml]
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+
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+RewriteCond %{DOCUMENT_ROOT}/cached/%{REQUEST_URI}.(html|xml|json|opml|svg) -f
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+RewriteRule .* cached/%{REQUEST_URI}.%1 [L]
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+
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+RewriteCond %{REQUEST_FILENAME} -s [OR]
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+RewriteCond %{REQUEST_FILENAME} -l [OR]
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+RewriteCond %{REQUEST_FILENAME} -d
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+RewriteRule ^.*$ - [NC,L]
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+
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+RewriteRule ^.*$ index.php [NC,L]
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+]]></programlisting>
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+ <para>
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+ The above assumes static files are cached to the directory ./public/cached.
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+ We'll cover the option setting this location, "public_dir", below.
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+ </para>
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+ <para>
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+ Due to the nature of static file caching, the backend class offers two
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+ additional methods: <methodname>remove()</methodname> and <methodname>
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+ removeRecursively()</methodname>. Both accept a request URI, which when
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+ mapped to the "public_dir" where static files are cached, and has a
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+ pre-stored extension appended, provides the name of either a static
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+ file to delete, or a directory path to delete recursively. Due to the
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+ restraints of <classname>Zend_Cache_Backend_Interface</classname>, all
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+ other methods such as <classname>save()</classname> accept an ID which
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+ is calculated by applying bin2hex() to a request URI.
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+ </para>
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+ <para>
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+ Given the level at which static caching operates, static file caching
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+ is addressed for simpler use with the <classname>
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+ Zend_Controller_Action_Helper_Cache</classname> action helper. This helper
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+ assists in setting which actions of a controller to cache, with what tags,
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+ and with which extension. It also offers methods for purging the cache by
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+ request URI or tag. Static file caching is also assisted by <classname>
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+ Zend_Cache_Manager</classname> which includes pre-configured configuration
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+ templates for a static cache (as Zend_Cache_Manager::PAGECACHE or "page").
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+ The defaults therein can be configured as needed to set up a "public_dir"
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+ location for caching, etc.
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+ </para>
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+ <note>
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+ <para>
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+ It should be noted that the static cache actually uses a secondary
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+ cache to store tags (obviously we can't store them elsewhere since
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+ a static cache does not invoke PHP if working correctly). This is
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+ just a standard Core cache, and should use a persistent backend such
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+ as File or TwoLevels (to take advantage of memory storage without
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+ sacrificing permanent persistance). The backend includes the option
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+ "tag_cache" to set this up (it is obligatory), or the <methodname>
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+ setInnerCache()</methodname> method.
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+ </para>
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+ </note>
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+ <table id="zend.cache.backends.static.table">
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+ <title>Static Backend Options</title>
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+ <tgroup cols="4">
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+ <thead>
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+ <row>
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+ <entry>Option</entry>
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+ <entry>Data Type</entry>
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+ <entry>Default Value</entry>
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+ <entry>Description</entry>
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+ </row>
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+ </thead>
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+ <tbody>
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+ <row>
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+ <entry><emphasis>public_dir</emphasis></entry>
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+ <entry><type>String</type></entry>
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+ <entry>NULL</entry>
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+ <entry>
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+ Directory where to store static files. This must exist
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+ in your public directory.
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>file_locking</emphasis></entry>
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+ <entry><type>Boolean</type></entry>
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+ <entry><constant>TRUE</constant></entry>
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+ <entry>
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+ Enable or disable file_locking : Can avoid cache corruption under
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+ bad circumstances but it doesn't help on multithread webservers
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+ or on <acronym>NFS</acronym> filesystems...
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>read_control</emphasis></entry>
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+ <entry><type>Boolean</type></entry>
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+ <entry><constant>TRUE</constant></entry>
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+ <entry>
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+ Enable / disable read control : if enabled, a control key is
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+ embedded in the cache file and this key is compared with the
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+ one calculated after the reading.
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>read_control_type</emphasis></entry>
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+ <entry><type>String</type></entry>
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+ <entry>'crc32'</entry>
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+ <entry>
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+ Type of read control (only if read control is enabled). Available values
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+ are : 'md5' (best but slowest), 'crc32' (lightly less safe but faster,
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+ better choice), 'adler32' (new choice, faster than crc32),
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+ 'strlen' for a length only test (fastest).
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>cache_file_umask</emphasis></entry>
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+ <entry><type>Integer</type></entry>
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+ <entry>0700</entry>
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+ <entry>
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+ umask for cached files.
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>cache_directory_umask</emphasis></entry>
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+ <entry><type>Integer</type></entry>
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+ <entry>0700</entry>
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+ <entry>
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+ Umask for directories created within public_dir.
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+ </entry>
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+ </row>
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+
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+ <row>
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+ <entry><emphasis>file_extension</emphasis></entry>
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+ <entry><type>String</type></entry>
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+ <entry>'.html'</entry>
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+ <entry>
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+ Default file extension for static files created. This
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+ can be configured on the fly, see <methodname>
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+ Zend_Cache_Backend_Static::save()</methodname> though
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+ generally it's recommended to rely on <classname>
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+ Zend_Controller_Action_Helper_Cache</classname> when
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+ doing so since it's simpler that way than messing with
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+ arrays/serialization manually.
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>index_filename</emphasis></entry>
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+ <entry><type>String</type></entry>
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+ <entry>'index'</entry>
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+ <entry>
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+ If a request URI does not contain sufficient information
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+ to construct a static file (usually this means an index
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+ call, e.g. URI of '/'), the index_filename is used instead.
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+ So '' or '/' would map to 'index.html' (assuming the default
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+ file_extension is '.html').
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>tag_cache</emphasis></entry>
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+ <entry><type>Object</type></entry>
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+ <entry>NULL</entry>
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+ <entry>
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+ Used to set an 'inner' cache utilised to store tags
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+ and file extensions associated with static files. This
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+ MUST be set or the static cache cannot be tracked and
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+ managed.
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+ </entry>
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+ </row>
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+ <row>
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+ <entry><emphasis>disable_caching</emphasis></entry>
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+ <entry><type>Boolean</type></entry>
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+ <entry>FALSE</entry>
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+ <entry>
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+ If set to TRUE, static files will not be cached. This
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+ will force all requests to be dynamic even if marked
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+ to be cached in Controllers. Useful for debugging.
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+ </entry>
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+ </row>
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+ </tbody>
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+ </tgroup>
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+ </table>
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+ </sect2>
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+
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</sect1>
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<!--
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vim:se ts=4 sw=4 et:
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padraic