+ +
+

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.

+ +
+

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;
+
+
+

You can also prefix cache item names via the key_prefix setting, which is useful +to avoid collisions when you’re running multiple applications on the same environment.

+
$this->load->driver('cache',
+        array('adapter' => 'apc', 'backup' => 'file', 'key_prefix' => 'my_')
+);
+
+$this->cache->get('foo'); // Will get the cache entry named 'my_foo'
+
+
+
+
+

Class Reference

+
+
+class CI_Cache
+
+
+is_supported($driver)
+
+++ + + + + + + + +
Parameters:
    +
  • $driver (string) – the name of the caching driver
    • +
+
Returns:

TRUE if supported, FALSE if not

+
Return type:

bool

+
+

This method is automatically called when accessing drivers via +$this->cache->get(). However, if the individual drivers are used, +make sure to call this method 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)
+
+++ + + + + + + + +
Parameters:
    +
  • $id (string) – Cache item name
    • +
+
Returns:

Item value or FALSE if not found

+
Return type:

mixed

+
+

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

+
$foo = $this->cache->get('my_cached_item');
+
+
+
+ +
+
+save($id, $data[, $ttl = 60[, $raw = FALSE]])
+
+++ + + + + + + + +
Parameters:
    +
  • $id (string) – Cache item name
    • +
  • $data (mixed) – the data to save
    • +
  • $ttl (int) – Time To Live, in seconds (default 60)
    • +
  • $raw (bool) – Whether to store the raw value
    • +
+
Returns:

TRUE on success, FALSE on failure

+
Return type:

string

+
+

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

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

Note

+

The $raw parameter is only utilized by APC and Memcache, +in order to allow usage of increment() and decrement().

+
+
+ +
+
+delete($id)
+
+++ + + + + + + + +
Parameters:
    +
  • $id (string) – name of cached item
    • +
+
Returns:

TRUE on success, FALSE on failure

+
Return type:

bool

+
+

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

+
$this->cache->delete('cache_item_id');
+
+
+
+ +
+
+increment($id[, $offset = 1])
+
+++ + + + + + + + +
Parameters:
    +
  • $id (string) – Cache ID
    • +
  • $offset (int) – Step/value to add
    • +
+
Returns:

New value on success, FALSE on failure

+
Return type:

mixed

+
+

Performs atomic incrementation of a raw stored value.

+
// 'iterator' has a value of 2
+
+$this->cache->increment('iterator'); // 'iterator' is now 3
+
+$this->cache->increment('iterator', 3); // 'iterator' is now 6
+
+
+
+ +
+
+decrement($id[, $offset = 1])
+
+++ + + + + + + + +
Parameters:
    +
  • $id (string) – Cache ID
    • +
  • $offset (int) – Step/value to reduce by
    • +
+
Returns:

New value on success, FALSE on failure

+
Return type:

mixed

+
+

Performs atomic decrementation of a raw stored value.

+
// 'iterator' has a value of 6
+
+$this->cache->decrement('iterator'); // 'iterator' is now 5
+
+$this->cache->decrement('iterator', 2); // 'iterator' is now 3
+
+
+
+ +
+
+clean()
+
+++ + + + + + +
Returns:TRUE on success, FALSE on failure
Return type:bool
+

This method will ‘clean’ the entire cache. If the deletion of the +cache files fails, the method will return FALSE.

+
$this->cache->clean();
+
+
+
+ +
+
+cache_info()
+
+++ + + + + + +
Returns:Information on the entire cache database
Return type:mixed
+

This method will return information on the entire cache.

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

Note

+

The information returned and the structure of the data is dependent +on which adapter is being used.

+
+
+ +
+
+get_metadata($id)
+
+++ + + + + + + + +
Parameters:
    +
  • $id (string) – Cache item name
    • +
+
Returns:

Metadata for the cached item

+
Return type:

mixed

+
+

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

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

Note

+

The information returned and the structure of the data is dependent +on which adapter is being used.

+
+
+ +
+ +
+
+

Drivers

+
+

Alternative PHP Cache (APC) Caching

+

All of the methods 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 methods 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 methods 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.

+
+
+

WinCache Caching

+

Under Windows, you can also utilize the WinCache driver.

+

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

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

For more information on WinCache, please see +http://php.net/wincache.

+
+
+

Redis Caching

+

Redis is an in-memory key-value store which can operate in LRU cache mode. +To use it, you need Redis server and phpredis PHP extension.

+

Config options to connect to redis server must be stored in the application/config/redis.php file. +Available options are:

+
$config['socket_type'] = 'tcp'; //`tcp` or `unix`
+$config['socket'] = '/var/run/redis.sock'; // in case of `unix` socket type
+$config['host'] = '127.0.0.1';
+$config['password'] = NULL;
+$config['port'] = 6379;
+$config['timeout'] = 0;
+
+
+

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

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

For more information on Redis, please see +http://redis.io.

+
+
+

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.

+
+
+
+ + +