Cache Pools and Supported Adapters ¶

Looking for Cache Items ¶

Cache Pools define three methods to look for cache items. The most common method is getItem($key), which returns the cache item identified by the given key:

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use Symfony\Component\Cache\Adapter\FilesystemAdapter;

$cache = new FilesystemAdapter('app.cache');
$latestNews = $cache->getItem('latest_news');

If no item is defined for the given key, the method doesn't return a null value but an empty object which implements the CacheItem class.

If you need to fetch several cache items simultaneously, use instead the getItems([$key1, $key2, ...]) method:

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// ...
$stocks = $cache->getItems(['AAPL', 'FB', 'GOOGL', 'MSFT']);

Again, if any of the keys doesn't represent a valid cache item, you won't get a null value but an empty CacheItem object.

The last method related to fetching cache items is hasItem($key), which returns true if there is a cache item identified by the given key:

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// ...
$hasBadges = $cache->hasItem('user_'.$userId.'_badges');

Saving Cache Items ¶

The most common method to save cache items is Psr\Cache\CacheItemPoolInterface::save, which stores the item in the cache immediately (it returns true if the item was saved or false if some error occurred):

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// ...
$userFriends = $cache->getItem('user_'.$userId.'_friends');
$userFriends->set($user->getFriends());
$isSaved = $cache->save($userFriends);

Sometimes you may prefer to not save the objects immediately in order to increase the application performance. In those cases, use the Psr\Cache\CacheItemPoolInterface::saveDeferred method to mark cache items as "ready to be persisted" and then call to Psr\Cache\CacheItemPoolInterface::commit method when you are ready to persist them all:

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// ...
$isQueued = $cache->saveDeferred($userFriends);
// ...
$isQueued = $cache->saveDeferred($userPreferences);
// ...
$isQueued = $cache->saveDeferred($userRecentProducts);
// ...
$isSaved = $cache->commit();

The saveDeferred() method returns true when the cache item has been successfully added to the "persist queue" and false otherwise. The commit() method returns true when all the pending items are successfully saved or false otherwise.

Removing Cache Items ¶

Cache Pools include methods to delete a cache item, some of them or all of them. The most common is Psr\Cache\CacheItemPoolInterface::deleteItem, which deletes the cache item identified by the given key (it returns true when the item is successfully deleted or doesn't exist and false otherwise):

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// ...
$isDeleted = $cache->deleteItem('user_'.$userId);

Use the Psr\Cache\CacheItemPoolInterface::deleteItems method to delete several cache items simultaneously (it returns true only if all the items have been deleted, even when any or some of them don't exist):

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// ...
$areDeleted = $cache->deleteItems(['category1', 'category2']);

Finally, to remove all the cache items stored in the pool, use the Psr\Cache\CacheItemPoolInterface::clear method (which returns true when all items are successfully deleted):

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// ...
$cacheIsEmpty = $cache->clear();

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$ php bin/console cache:pool:delete <cache-pool-name> <cache-key-name>

# deletes the "cache_key" item from the "cache.app" pool
$ php bin/console cache:pool:delete cache.app cache_key

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$ php bin/console cache:pool:clear <cache-pool-name>

# clears the "cache.app" pool
$ php bin/console cache:pool:clear cache.app

# clears the "cache.validation" and "cache.app" pool
$ php bin/console cache:pool:clear cache.validation cache.app