| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> |
| <head> |
| |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> |
| <title>Caching Driver : CodeIgniter User Guide</title> |
| |
| <style type='text/css' media='all'>@import url('../userguide.css');</style> |
| <link rel='stylesheet' type='text/css' media='all' href='../userguide.css' /> |
| |
| <script type="text/javascript" src="../nav/nav.js"></script> |
| <script type="text/javascript" src="../nav/prototype.lite.js"></script> |
| <script type="text/javascript" src="../nav/moo.fx.js"></script> |
| <script type="text/javascript" src="../nav/user_guide_menu.js"></script> |
| |
| <meta http-equiv='expires' content='-1' /> |
| <meta http-equiv= 'pragma' content='no-cache' /> |
| <meta name='robots' content='all' /> |
| <meta name='author' content='ExpressionEngine Dev Team' /> |
| <meta name='description' content='CodeIgniter User Guide' /> |
| |
| </head> |
| <body> |
| |
| <!-- START NAVIGATION --> |
| <div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div> |
| <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> |
| <div id="masthead"> |
| <table cellpadding="0" cellspacing="0" border="0" style="width:100%"> |
| <tr> |
| <td><h1>CodeIgniter User Guide Version 2.0.2</h1></td> |
| <td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td> |
| </tr> |
| </table> |
| </div> |
| <!-- END NAVIGATION --> |
| |
| |
| <!-- START BREADCRUMB --> |
| <table cellpadding="0" cellspacing="0" border="0" style="width:100%"> |
| <tr> |
| <td id="breadcrumb"> |
| <a href="http://codeigniter.com/">CodeIgniter Home</a> › |
| <a href="../index.html">User Guide Home</a> › |
| <a href="../general/drivers.html">Drivers</a> › |
| Caching Driver |
| </td> |
| <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> |
| </tr> |
| </table> |
| <!-- END BREADCRUMB --> |
| |
| <br clear="all" /> |
| |
| |
| <!-- START CONTENT --> |
| <div id="content"> |
| |
| <h1>Caching Driver</h1> |
| |
| <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> |
| |
| <h2>Table of Contents</h2> |
| <ul> |
| <li><a href="#example_usage" title="Example Usage">Example Usage</a></li> |
| <li><a href="#function_reference" title="Function Reference">Function Reference</a></li> |
| </ul> |
| |
| <h3>Available Drivers</h3> |
| <ul> |
| <li><a href="#apc" title="APC Cache">Alternative PHP Cache (APC) Caching</a></li> |
| <li><a href="#file" title="File Caching">File-based Caching</a></li> |
| <li><a href="#memcached" title="Memcached">Memcached Caching</a></li> |
| <li><a href="#dummy" title="Dummy Caching">Dummy Cache</a></li> |
| </ul> |
| |
| <h2 id="example_usage">Example Usage</h2> |
| |
| <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> |
| |
| <code> |
| $this->load->driver('cache', array('adapter' => 'apc', 'backup' => 'file'));<br /> |
| <br /> |
| if ( ! $foo = $this->cache->get('foo'))<br /> |
| {<br /> |
| echo 'Saving to the cache!<br />';<br /> |
| $foo = 'foobarbaz!';<br /> |
| <br /> |
| // Save into the cache for 5 minutes<br /> |
| $this->cache->save('foo', $foo, 300);<br /> |
| }<br /> |
| <br /> |
| echo $foo; |
| </code> |
| |
| <h1 id="function_reference">Function Reference</h1> |
| |
| <h2>is_supported(<var>driver</var>['string'])</h2> |
| |
| <p>This function is automatically called when accessing drivers via <samp>$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> |
| |
| <code> |
| if ($this->cache->apc->is_supported())<br /> |
| {<br /> |
| if ($data = $this->cache->apc->get('my_cache'))<br /> |
| {<br /> |
| // do things.<br /> |
| }<br /> |
| } |
| </code> |
| |
| <h2>get(<var>id</var>['string'])</h2> |
| |
| <p>This function will attempt to fetch an item from the cache store. If the item does not exist, the function will return <samp>FALSE</samp>.</p> |
| <code>$foo = $this->cache->get('my_cached_item');</code> |
| |
| <h2>save(<var>id</var>['string'], <var>data</var>['mixed'], <var>ttl</var>['int'])</h2> |
| |
| <p>This function will save an item to the cache store. If saving fails, the function will return <samp>FALSE</samp>.</p> |
| <p>The optional third parameter (Time To Live) defaults to 60 seconds.</p> |
| <code>$this->cache->save('cache_item_id', 'data_to_cache');</code> |
| |
| <h2>delete(<var>id</var>['string'])</h2> |
| |
| <p>This function will delete a specific item from the cache store. If item deletion fails, the function will return <samp>FALSE</samp>.</p> |
| <code>$this->cache->delete('cache_item_id');</code> |
| |
| <h2>clean()</h2> |
| |
| <p>This function will 'clean' the entire cache. If the deletion of the cache files fails, the function will return <samp>FALSE</samp>.</p> |
| |
| <code>$this->cache->clean();</code> |
| |
| <h2>cache_info()</h2> |
| |
| <p>This function will return information on the entire cache.</p> |
| |
| <code>var_dump($this->cache->cache_info());</code> |
| |
| <h2>get_metadata(<var>id</var>['string'])</h2> |
| |
| <p>This function will return detailed information on a specific item in the cache.</p> |
| |
| <code>var_dump($this->cache->get_metadata('my_cached_item'));</code> |
| |
| <h1>Drivers</h1> |
| |
| <h2 id="apc">Alternative PHP Cache (APC) Caching</h2> |
| |
| <p>All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:</p> |
| <code>$this->load->driver('cache');<br /> |
| $this->cache->apc->save('foo', 'bar', 10);</code> |
| <p>For more information on APC, please see <a href="http://php.net/apc">http://php.net/apc</a></p> |
| |
| <h2 id="file">File-based Caching</h2> |
| |
| <p>Unlike caching from the Output Class, the driver file-based caching allows for pieces of view files to be cached. Use this with care, and make sure to benchmark your application, as a point can come where disk I/O will negate positive gains by caching.</p> |
| |
| <p>All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:</p> |
| <code>$this->load->driver('cache');<br /> |
| $this->cache->file->save('foo', 'bar', 10);</code> |
| |
| <h2 id="memcached">Memcached Caching</h2> |
| |
| <p>Multiple Memcached servers can be specified in the memcached.php configuration file, located in the <samp>application/config/</samp> directory. |
| |
| <p>All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:</p> |
| <code>$this->load->driver('cache');<br /> |
| $this->cache->memcached->save('foo', 'bar', 10);</code> |
| |
| <p>For more information on Memcached, please see <a href="http://php.net/memcached">http://php.net/memcached</a></p> |
| |
| <h2 id="dummy">Dummy Cache</h2> |
| |
| <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> |
| |
| </div> |
| <!-- END CONTENT --> |
| |
| |
| <div id="footer"> |
| <p> |
| Previous Topic: <a href="errors.html">Error Handling</a> |
| · |
| <a href="#top">Top of Page</a> · |
| <a href="../index.html">User Guide Home</a> · |
| Next Topic: <a href="profiling.html">Profiling Your Application</a> |
| </p> |
| <p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006 - 2011 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p> |
| </div> |
| |
| </body> |
| </html> |