Cache
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Using cache is a great way of making your application run quicker. The Symfony cache component is shipped with many adapters to different storages. Every adapter is developed for high performance.
The following example shows a typical usage of the cache:
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if (!$cache->has('my_cache_key')) {
// ... do some HTTP request or heavy computations
$cache->set('my_cache_key', 'foobar', 3600);
}
echo $cache->get('my_cache_key'); // 'foobar'
// ... and to remove the cache key
$cache->delete('my_cache_key');
Symfony supports PSR-6 and PSR-16 cache interfaces. You can read more about these at the component documentation.
Configuring Cache with FrameworkBundle
When configuring the cache component there are a few concepts you should know of:
- Pool
- This is a service that you will interact with. Each pool will always have its own namespace and cache items. There is never a conflict between pools.
- Adapter
- An adapter is a template that you use to create Pools.
- Provider
- A provider is a service that some adapters are using to connect to the storage. Redis and Memcached are example of such adapters. If a DSN is used as the provider then a service is automatically created.
There are two pools that are always enabled by default. They are cache.app
and
cache.system
. The system cache is used for things like annotations, serializer,
and validation. The cache.app
can be used in your code. You can configure which
adapter (template) they use by using the app
and system
key like:
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# app/config/config.yml
framework:
cache:
app: cache.adapter.filesystem
system: cache.adapter.system
The Cache component comes with a series of adapters already created:
- cache.adapter.apcu
- cache.adapter.doctrine
- cache.adapter.filesystem
- cache.adapter.memcached
- cache.adapter.pdo
- cache.adapter.redis
- PHPFileAdapter
- PHPArrayAdapter
- ChainAdapter
- ProxyAdapter
cache.adapter.psr6
cache.adapter.system
NullAdapter
Some of these adapters could be configured via shortcuts. Using these shortcuts
will create pool with service id of cache.[type]
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# app/config/config.yml
framework:
cache:
directory: '%kernel.cache_dir%/pools' # Only used with cache.adapter.filesystem
# service: cache.doctrine
default_doctrine_provider: 'app.doctrine_cache'
# service: cache.psr6
default_psr6_provider: 'app.my_psr6_service'
# service: cache.redis
default_redis_provider: 'redis://localhost'
# service: cache.memcached
default_memcached_provider: 'memcached://localhost'
# service: cache.pdo
default_pdo_provider: 'doctrine.dbal.default_connection'
Creating Custom Pools
You can also create more customized pools. All you need is an adapter:
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# app/config/config.yml
framework:
cache:
default_memcached_provider: 'memcached://localhost'
pools:
my_cache_pool:
provider: cache.adapter.filesystem
cache.acme:
adapter: cache.adapter.memcached
cache.foobar:
adapter: cache.adapter.memcached
provider: 'memcached://user:password@example.com'
The configuration above will create 3 services: my_cache_pool
, cache.acme
and cache.foobar
. The my_cache_pool
pool is using the filesystem adapter
and the other two are using the MemcachedAdapter.
The cache.acme
pool is using the Memcached server on localhost and cache.foobar
is using the Memcached server at example.com.
For advanced configurations it could sometimes be useful to use a pool as an adapter.
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# app/config/config.yml
framework:
cache:
app: my_configured_app_cache
pools:
my_cache_pool:
adapter: cache.adapter.memcached
provider: 'memcached://user:password@example.com'
cache.short_cache:
adapter: my_cache_pool
default_lifetime: 60
cache.long_cache:
adapter: my_cache_pool
default_lifetime: 604800
my_configured_app_cache:
# "cache.adapter.filesystem" is the default for "cache.app"
adapter: cache.adapter.filesystem
default_lifetime: 3600
Custom Provider Options
Some providers have specific options that can be configured. The
RedisAdapter allows you to
create providers with option timeout
, retry_interval
. etc. To use these
options with non-default values you need to create your own \Redis
provider
and use that when configuring the pool.
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# app/config/config.yml
framework:
cache:
pools:
cache.my_redis:
adapter: cache.adapter.redis
provider: app.my_custom_redis_provider
services:
app.my_custom_redis_provider:
class: \Redis
factory: ['Symfony\Component\Cache\Adapter\RedisAdapter', 'createConnection']
arguments:
- 'redis://localhost'
- { retry_interval: 2, timeout: 10 }
Creating a Cache Chain
Different cache adapters have different strengths and weaknesses. Some might be really quick but optimized to store small items and some may be able to contain a lot of data but are quite slow. To get the best of both worlds you may use a chain of adapters.
A cache chain combines several cache pools into a single one. When storing an item in a cache chain, Symfony stores it in all pools sequentially. When retrieving an item, Symfony tries to get it from the first pool. If it's not found, it tries the next pools until the item is found or an exception is thrown. Because of this behavior, it's recommended to define the adapters in the chain in order from the fastest to the slowest.
If an error happens when storing an item in a pool, Symfony stores it in the other pools and no exception is thrown. Later, when the item is retrieved, Symfony stores the item automatically in all the missing pools.
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# app/config/config.yml
framework:
cache:
pools:
my_cache_pool:
adapter: cache.adapter.psr6
provider: app.my_cache_chain_adapter
cache.my_redis:
adapter: cache.adapter.redis
provider: 'redis://user:password@example.com'
cache.apcu:
adapter: cache.adapter.apcu
cache.array:
adapter: cache.adapter.filesystem
services:
app.my_cache_chain_adapter:
class: Symfony\Component\Cache\Adapter\ChainAdapter
arguments:
- ['@cache.array', '@cache.apcu', '@cache.my_redis']
- 31536000 # One year
Note
In this configuration the my_cache_pool
pool is using the cache.adapter.psr6
adapter and the app.my_cache_chain_adapter
service as a provider. That is
because ChainAdapter
does not support the cache.pool
tag. So it is decorated
with the ProxyAdapter
.
Clearing the Cache
To clear the cache you can use the bin/console cache:pool:clear [pool]
command.
That will remove all the entries from your storage and you will have to recalculate
all values. You can also group your pools into "cache clearers". There are 3 cache
clearers by default:
cache.global_clearer
cache.system_clearer
cache.app_clearer
The global clearer clears all the cache in every pool. The system cache clearer
is used in the bin/console cache:clear
command. The app clearer is the default
clearer.
Clear one pool:
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$ php bin/console cache:pool:clear my_cache_pool
Clear all custom pools:
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$ php bin/console cache:pool:clear cache.app_clearer
Clear all caches everywhere:
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$ php bin/console cache:pool:clear cache.global_clearer