193 lines
8.1 KiB
HTML
193 lines
8.1 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>Caching Driver : CodeIgniter User Guide</title>
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<style type='text/css' media='all'>@import url('../userguide.css');</style>
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<link rel='stylesheet' type='text/css' media='all' href='../userguide.css' />
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<script type="text/javascript" src="../nav/nav.js"></script>
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<script type="text/javascript" src="../nav/prototype.lite.js"></script>
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<script type="text/javascript" src="../nav/moo.fx.js"></script>
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<script type="text/javascript" src="../nav/user_guide_menu.js"></script>
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<meta http-equiv='expires' content='-1' />
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<meta http-equiv= 'pragma' content='no-cache' />
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<meta name='robots' content='all' />
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<meta name='author' content='ExpressionEngine Dev Team' />
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<meta name='description' content='CodeIgniter User Guide' />
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</head>
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<body>
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<!-- START NAVIGATION -->
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<div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div>
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<div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div>
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<div id="masthead">
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<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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<tr>
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<td><h1>CodeIgniter User Guide Version 2.1.3</h1></td>
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<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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</tr>
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</table>
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</div>
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<!-- END NAVIGATION -->
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<!-- START BREADCRUMB -->
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<table cellpadding="0" cellspacing="0" border="0" style="width:100%">
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<tr>
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<td id="breadcrumb">
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<a href="http://codeigniter.com/">CodeIgniter Home</a> ›
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<a href="../index.html">User Guide Home</a> ›
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<a href="../general/drivers.html">Drivers</a> ›
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Caching Driver
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</td>
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<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td>
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</tr>
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</table>
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<!-- END BREADCRUMB -->
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<br clear="all" />
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<!-- START CONTENT -->
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<div id="content">
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<h1>Caching Driver</h1>
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<p>CodeIgniter features wrappers around some of the most popular forms of fast and dynamic caching. All but file-based caching require specific server requirements, and a Fatal Exception will be thrown if server requirements are not met.</p>
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<h2>Table of Contents</h2>
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<ul>
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<li><a href="#example_usage" title="Example Usage">Example Usage</a></li>
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<li><a href="#function_reference" title="Function Reference">Function Reference</a></li>
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</ul>
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<h3>Available Drivers</h3>
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<ul>
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<li><a href="#apc" title="APC Cache">Alternative PHP Cache (APC) Caching</a></li>
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<li><a href="#file" title="File Caching">File-based Caching</a></li>
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<li><a href="#memcached" title="Memcached">Memcached Caching</a></li>
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<li><a href="#dummy" title="Dummy Caching">Dummy Cache</a></li>
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</ul>
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<h2 id="example_usage">Example Usage</h2>
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<p>The following example will load the cache driver, specify <a href="#apc" title="APC">APC</a> as the driver to use, and fall back to file-based caching if APC is not available in the hosting environment.</p>
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<code>
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$this->load->driver('cache', array('adapter' => 'apc', 'backup' => 'file'));<br />
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<br />
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if ( ! $foo = $this->cache->get('foo'))<br />
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{<br />
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echo 'Saving to the cache!<br />';<br />
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$foo = 'foobarbaz!';<br />
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<br />
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// Save into the cache for 5 minutes<br />
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$this->cache->save('foo', $foo, 300);<br />
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}<br />
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<br />
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echo $foo;
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</code>
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<h1 id="function_reference">Function Reference</h1>
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<h2>is_supported(<var>driver</var>['string'])</h2>
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<p>This function is automatically called when accessing drivers via <samp>$this->cache->get()</samp>. However, if the individual drivers are used, make sure to call this function to ensure the driver is supported in the hosting environment.</p>
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<code>
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if ($this->cache->apc->is_supported())<br />
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{<br />
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if ($data = $this->cache->apc->get('my_cache'))<br />
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{<br />
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// do things.<br />
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}<br />
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}
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</code>
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<h2>get(<var>id</var>['string'])</h2>
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<p>This function will attempt to fetch an item from the cache store. If the item does not exist, the function will return <samp>FALSE</samp>.</p>
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<code>$foo = $this->cache->get('my_cached_item');</code>
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<h2>save(<var>id</var>['string'], <var>data</var>['mixed'], <var>ttl</var>['int'])</h2>
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<p>This function will save an item to the cache store. If saving fails, the function will return <samp>FALSE</samp>.</p>
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<p>The optional third parameter (Time To Live) defaults to 60 seconds.</p>
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<code>$this->cache->save('cache_item_id', 'data_to_cache');</code>
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<h2>delete(<var>id</var>['string'])</h2>
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<p>This function will delete a specific item from the cache store. If item deletion fails, the function will return <samp>FALSE</samp>.</p>
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<code>$this->cache->delete('cache_item_id');</code>
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<h2>clean()</h2>
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<p>This function will 'clean' the entire cache. If the deletion of the cache files fails, the function will return <samp>FALSE</samp>.</p>
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<code>$this->cache->clean();</code>
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<h2>cache_info()</h2>
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<p>This function will return information on the entire cache.</p>
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<code>var_dump($this->cache->cache_info());</code>
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<h2>get_metadata(<var>id</var>['string'])</h2>
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<p>This function will return detailed information on a specific item in the cache.</p>
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<code>var_dump($this->cache->get_metadata('my_cached_item'));</code>
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<h1>Drivers</h1>
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<h2 id="apc">Alternative PHP Cache (APC) Caching</h2>
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<p>All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:</p>
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<code>$this->load->driver('cache');<br />
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$this->cache->apc->save('foo', 'bar', 10);</code>
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<p>For more information on APC, please see <a href="http://php.net/apc">http://php.net/apc</a></p>
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<h2 id="file">File-based Caching</h2>
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<p>Unlike caching from the Output Class, the driver file-based caching allows for pieces of view files to be cached. Use this with care, and make sure to benchmark your application, as a point can come where disk I/O will negate positive gains by caching.</p>
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<p>All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:</p>
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<code>$this->load->driver('cache');<br />
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$this->cache->file->save('foo', 'bar', 10);</code>
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<h2 id="memcached">Memcached Caching</h2>
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<p>Multiple Memcached servers can be specified in the memcached.php configuration file, located in the <samp>application/config/</samp> directory.
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<p>All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:</p>
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<code>$this->load->driver('cache');<br />
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$this->cache->memcached->save('foo', 'bar', 10);</code>
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<p>For more information on Memcached, please see <a href="http://php.net/memcached">http://php.net/memcached</a></p>
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<h2 id="dummy">Dummy Cache</h2>
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<p>This is a caching backend that will always 'miss.' It stores no data, but lets you keep your caching code in place in environments that don't support your chosen cache.</p>
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</div>
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<!-- END CONTENT -->
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<div id="footer">
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<p>
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Previous Topic: <a href="zip.html">Zip Encoding Class</a>
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·
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<a href="#top">Top of Page</a> ·
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<a href="../index.html">User Guide Home</a> ·
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Next Topic: <a href="../database/index.html">Database Class</a>
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</p>
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<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2012 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p>
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</div>
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</body>
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</html>
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