Cache

Overview:

Cache provides a multi-strategy cache facade. It selects a backend driver with a first-come, first-served strategy and exposes a consistent API for get/set/exists/increment operations.

Use Cache to memoize expensive queries or computed payloads and share cached values across requests with a driver strategy that can degrade gracefully.

Key behavior:

• Cache can be globally enabled or disabled with Cache::enabled().
• Keys are hashed with Cache::hash() and can be grouped.
• Default value can be a callable and will be computed and stored if missing.

Public API:

• Cache::using($driver) registers the first valid driver from a string, list, or map of driver => options.
• Cache::get($key, $default = '', $expire = 0) returns cached value or resolves and stores default.
• Cache::set($key, $value, $expire = 0) writes a value.
• Cache::delete($key) removes a key.
• Cache::exists($key) checks existence, respecting enabled.
• Cache::flush() clears the underlying store.
• Cache::inc($key, $value = 1) increments a key.
• Cache::dec($key, $value = 1) decrements a key.
• Cache::hash($key, $group = null) returns a stable hash, with optional group prefix.

Events:

• Uses the Events trait, but Cache does not emit explicit events itself.

Example:

Cache::using(['redis', 'files', 'memory']);
$user = Cache::get('user:42', function () {
    return User::load(42);
}, 300);

The Cache module allow you to handle an object persistence between requests and store heavy-computing persistent data.

Retrieve a value

---

The simplest way to retrieve a value from cache is via the get method.

$shares = Cache::get('shares');

You can optionally pass a default value and an expire time. The dafault value can be either a mixed or a callable. If you pass the latter it will invoked and the returned value will be used as the default value.

$help = Cache::get('help',true);

$shares = Cache::get('shares',function(){
   return calc_user_shares();
});

Important: When the default value is used (from a cache miss), the cache value will be setted.

$value_generator = function(){
	return time();
};

echo Cache::get('memento',$value_generator); // (Cache MISS) returned : 1389122001 ($value_generator called)
echo Cache::get('memento',$value_generator); // (Cache HIT) returned : 1389122001
echo Cache::get('memento',$value_generator); // (Cache HIT) returned : 1389122001

Setting a value

---

You can set a value for a key with the set method.

Cache::set('friend_or_foe','friend');

You can pass an optional expiration parameter in seconds.

Cache::set('friend_or_foe','friend',15); // Expire in 15 sec

echo Cache::get('friend_or_foe'); // friend
sleep(20);
echo Cache::get('friend_or_foe'); // (no value)

Delete a cached key

---

You can delete a cached key with the delete method.

Cache::delete('friend_or_foe');

Flush all cached keys

---

You can delete all cached keys with the flush method.

Cache::flush();

Check if a key is cached

---

You can delete a cached key with the exists method.

if ( Cache::exists('user_info') ) { ... }

Increment/Decrement a value

---

You can increment/decrement a cached key value with the inc and dec methods.

Example

Event::on('user.login',function(){
	Cache::inc('user.logged');
});

Event::on('user.logout',function(){
	Cache::dec('user.logged');
});

Default inc/dec value is 1, you can however change it by passing the increment/decrement value as the second parameter of the inc/dec methods.

Event::on('boss.killed',function(){
	Cache::inc('user.score',1000);
});

Changing caching strategy/driver

---

You can choose the Cache driver via the using method. The optional second parameter is dictionary of init paramenters to pass to the selected driver.

The default driver is Memory, a request-only persistent storage.

Example

// Use File-based caching
Cache::using('File',[
	'cache_dir' => __DIR__ . '/cache'
]);

Enable/Disable cache

---

You can bybass all cache by passing false to the Cache::enable method.

Cache::enabled(false);

A common use for this is for disabling cache in debug mode.

Cache::enabled(!Options::get('debug',false));