CodeIgniter User Guide Version 2.2.6

Table of Contents Page

Caching Driver

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.

Table of Contents

• Example Usage
• Function Reference

Available Drivers

• Alternative PHP Cache (APC) Caching
• File-based Caching
• Memcached Caching
• Dummy Cache

Example Usage

The following example will load the cache driver, specify APC as the driver to use, and fall back to file-based caching if APC is not available in the hosting environment.

$this->load->driver('cache', array('adapter' => 'apc', 'backup' => 'file'));

if ( ! $foo = $this->cache->get('foo'))
{
     echo 'Saving to the cache!<br />';
     $foo = 'foobarbaz!';

     // Save into the cache for 5 minutes
     $this->cache->save('foo', $foo, 300);
}

echo $foo;

Function Reference

is_supported(driver['string'])

This function is automatically called when accessing drivers via $this->cache->get(). However, if the individual drivers are used, make sure to call this function to ensure the driver is supported in the hosting environment.

if ($this->cache->apc->is_supported())
{
     if ($data = $this->cache->apc->get('my_cache'))
     {
          // do things.
     }
}

get(id['string'])

This function will attempt to fetch an item from the cache store. If the item does not exist, the function will return FALSE.

$foo = $this->cache->get('my_cached_item');

save(id['string'], data['mixed'], ttl['int'])

This function will save an item to the cache store. If saving fails, the function will return FALSE.

The optional third parameter (Time To Live) defaults to 60 seconds.

$this->cache->save('cache_item_id', 'data_to_cache');

delete(id['string'])

This function will delete a specific item from the cache store. If item deletion fails, the function will return FALSE.

$this->cache->delete('cache_item_id');

clean()

This function will 'clean' the entire cache. If the deletion of the cache files fails, the function will return FALSE.

$this->cache->clean();

cache_info()

This function will return information on the entire cache.

var_dump($this->cache->cache_info());

get_metadata(id['string'])

This function will return detailed information on a specific item in the cache.

var_dump($this->cache->get_metadata('my_cached_item'));

Drivers

Alternative PHP Cache (APC) Caching

All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:

$this->load->driver('cache');
$this->cache->apc->save('foo', 'bar', 10);

For more information on APC, please see http://php.net/apc

File-based Caching

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.

All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:

$this->load->driver('cache');
$this->cache->file->save('foo', 'bar', 10);

Memcached Caching

Multiple Memcached servers can be specified in the memcached.php configuration file, located in the application/config/ directory.

All of the functions listed above can be accessed without passing a specific adapter to the driver loader as follows:

$this->load->driver('cache');
$this->cache->memcached->save('foo', 'bar', 10);

For more information on Memcached, please see http://php.net/memcached

Dummy Cache

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.

Previous Topic:  Zip Encoding Class    ·   Top of Page   ·   User Guide Home   ·   Next Topic:  Database Class

CodeIgniter  ·  Copyright © 2006 - 2014  ·  EllisLab, Inc.  ·  Copyright © 2014 - 2015  ·  British Columbia Institute of Technology