The document discusses the Symfony Cache Component and how it can be used to speed up applications with a new caching layer. It introduces key concepts like PSR-6 and PSR-16 caching interfaces, the Symfony Cache Component which implements these interfaces, and Symfony Simple Cache which provides a simpler interface. Real use cases are presented where caching can improve performance for applications with high traffic by caching queries, API responses, and computationally intensive tasks.

1. Symfony Cache Component
speed-up your application with
a new layer of cache

2. simone d’amico
software engineer @
@dymissy
sd@ideato.it

3. Symfony Cache Component

6. Agenda
How did we cache before
Symfony 3.1?
Symfony Cache Component
Symfony Simple Cache
Real Use Case

7. In the beginning there was…
Cache before Symfony 3.1
➔ Apc
➔ Memcache / Memcached
➔ Redis
➔ …

8. Doctrine Cache
doctrine_cache:
class:
DoctrineCommonCacheFilesystemCac
he
arguments:
- '/tmp/doctrine_cache/'
public: true
$cache = $this->get('doctrine_cache');
$feed = $cache->fetch('feed');
if (!$feed) {
$feed = $feedReader->load();
$cache->save('feed', $feed, 60);
}
return $feed;

9. …then Symfony 3.1 was released

10. Symfony Cache Component
Symfony Cache Component
➔ Strict implementation of PSR-6: Caching Interface
➔ Provides adapters for the most common caching
backends
➔ Compatible with every Doctrine Cache adapter

11. Symfony Cache Component
Symfony Cache Component
Some of adapters provided:
➔ Apcu Cache adapter
➔ Array Cache adapter
➔ Chain Cache adapter
➔ Doctrine Cache adapter
➔ Filesystem Cache adapter
➔ Memcached Cache adapter
➔ PDO & Doctrine Cache DBAL adapter
➔ Php Array Cache adapter
➔ Proxy Cache adapter
➔ Redis Cache adapter

12. PSR-6: Caching Interface
PSR6: Caching Interface
➔ Goal
Allow developers to create cache-aware libraries that can be
integrated into existing frameworks and systems without the need
for custom development.
➔ Data
Implementing libraries MUST support all serializable PHP data types,
including: strings, integers, floats, boolean, null, arrays, object

13. PSR-6: Key Concepts
PSR6: Caching Interface
➔ Pool
Collection of items in a caching system. The pool is a
logical Repository of all items it contains
➔ Item
Single key/value pair within a Pool

14. PSR-6: CacheItemPoolInterface
public function getItem($key);
public function getItems(array $keys = []);
public function hasItem($key);
public function clear();
public function deleteItem($key);
public function deleteItems(array $keys);
public function save(CacheItemInterface
$item);
public function
saveDeferred(CacheItemInterface $item);
public function commit();

15. PSR-6: CacheItemInterface
public function getKey();
public function get();
public function isHit();
public function set($value);
public function expiresAt($expiration);
public function expiresAfter($time);

16. Symfony Cache Component: Key Concepts
Symfony Cache Component
➔ Pool
➔ Item
➔ Adapter
SymfonyComponentCacheAdapterAdapterInterface
SymfonyComponentCacheCacheItem
SymfonyComponentCacheAdapter*Adapter

17. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;

18. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/symfony_cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
1

19. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/symfony_cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
2

20. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/symfony_cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
3

21. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/symfony_cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
4

22. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/symfony_cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
5

23. Symfony Cache Component
symfony_cache:
class:
SymfonyComponentCacheAdapter
FilesystemAdapter
arguments:
- ''
- 0
- '/tmp/symfony_cache/'
public: true
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
6

24. OK. Cool. But…

25. …can we do it in a simpler way?

26. PSR-16: Common Interface for Caching Libraries
PSR16: Caching Interface
➔ Goal
Simplify PSR-6 Interface for easier use cases
➔ Data
Implementing libraries MUST support all serializable PHP
data types, including: strings, integers, floats, boolean,
null, arrays, object

27. PSR-16: CacheInterface
public function get($key, $default = null);
public function set($key, $value, $ttl = null);
public function delete($key);
public function clear();
public function getMultiple($keys, $default = null);
public function setMultiple($values, $ttl = null);
public function deleteMultiple($keys);
public function has($key);

28. Symfony Simple Cache
Symfony Simple Cache
➔ Available from Symfony 3.3
➔ Implementation of PSR-16

29. Symfony Simple Cache
simple_cache:
class:
SymfonyComponentCacheSimpleF
ilesystemCache
arguments:
- ''
- 0
- '/tmp/cache/'
public: true
$cache = $this->get('simple_cache');
if ($cache->has('feed')) {
return $cache->get('feed');
}
$feed = $feedReader->load();
$cache->set('feed', $feed, 60);
return $feed;

30. Symfony Simple Cache
simple_cache:
class:
SymfonyComponentCacheSimpleF
ilesystemCache
arguments:
- ''
- 0
- '/tmp/cache/'
public: true
$cache = $this->get('simple_cache');
if ($cache->has('feed')) {
return $cache->get('feed');
}
$feed = $feedReader->load();
$cache->set('feed', $feed, 60);
return $feed;
1

31. Symfony Simple Cache
simple_cache:
class:
SymfonyComponentCacheSimpleF
ilesystemCache
arguments:
- ''
- 0
- '/tmp/cache/'
public: true
$cache = $this->get('simple_cache');
if ($cache->has('feed')) {
return $cache->get('feed');
}
$feed = $feedReader->load();
$cache->set('feed', $feed, 60);
return $feed;
2

32. Symfony Simple Cache
simple_cache:
class:
SymfonyComponentCacheSimpleF
ilesystemCache
arguments:
- ''
- 0
- '/tmp/cache/'
public: true
$cache = $this->get('simple_cache');
if ($cache->has('feed')) {
return $cache->get('feed');
}
$feed = $feedReader->load();
$cache->set('feed', $feed, 60);
return $feed;
3

33. Symfony Simple Cache
$cache = $this->get('simple_cache');
if ($cache->has('feed')) {
return $cache->get('feed');
}
$feed = $feedReader->load();
$cache->set('feed', $feed, 60);
return $feed;
$cache = $this->get('symfony_cache');
$cacheItem = $cache->getItem('feed');
if($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $feedReader->load();
$cacheItem->set($feed);
$cacheItem->expiresAfter(60);
$cache->save($cacheItem);
return $feed;
Cache Component Simple Cache

34. Simple Cache looks simpler than Cache Component.
Why should we use the component?

35. Symfony Cache Component
Symfony Cache Component
➔ Tags
➔ ChainCache Adapter
➔ ProxyCache Adapter
➔ Symfony FrameworkBundle Integration

36. Symfony Cache Component
Symfony Cache Component
➔ Tags
➔ ChainCache Adapter
➔ ProxyCache Adapter
➔ Symfony FrameworkBundle Integration

37. Real use case scenario

38. Domain
Real Use Case Scenario
➔ Thousands of unique visitors per day
➔ Millions of page requested per day
➔ Distributed system architecture
➔ Different layers of caching
➔ Performance matters

39. Domain
Real Use Case Scenario
➔ Different caching strategies:
- Slow queries with low refresh rate
- Loading data from external APIs with
low rate limit
- CPU intensive tasks
- …

40. Real use case scenario
cache:
default_redis_provider: "%app_cache_redis_provider%"
default_memcached_provider: "%app_cache_memcached_provider%"
pools:
app.cache.rating:
adapter: cache.adapter.redis
default_lifetime: 21600
app.cache.api:
adapter: cache.adapter.memcached
default_lifetime: 3600
app.cache.customer:
adapter: cache.app #defaults to cache.adapter.filesystem
default_lifetime: 86400
public: true
config.yml

41. Real use case scenario
$cache = $this->get('app.cache.customer');
$cacheItem = $cache->getItem('customer14');
if ($cacheItem->isHit()) {
return $cacheItem->get();
}
//...
Use the service in a Controller, UseCase, whatever…

42. Invalidate cache by tags
$cacheItem = $cache->getItem('customer15');
$product = $this->repository->find('customer15');
$cacheItem->set($product);
$cacheItem->tag(['reviews', 'customers', 'customer15']);
$cacheItem->expiresAt(new DateTimeImmutable('tomorrow'));
$cache->save($cacheItem);
//...
$cache->invalidateTags(['customer15']);
$cache->invalidateTags(['customers']);
Tag the cached content in order to invalidate easily

43. Clear cache pools
$ ./bin/console cache:pool:clear <cache pool or clearer 1> [...<cache
pool or clearer N>]
$ ./bin/console cache:pool:clear app.cache.customer
$ ./bin/console cache:pool:clear app.cache.custom_service
Symfony FrameworkBundle provides specific command for clear cache pools.

44. Questa è una diapositiva per l’inserimento di 1 immagine orizzontale con didascalia
Profiler

45. Profiler

46. Bonus

47. Domain
Real Use Case Scenario
➔ Different caching strategies:
- Slow queries with low refresh rate
- Loading data from external APIs with
low rate limit
- CPU intensive tasks
- …

48. Questa è una diapositiva per l’inserimento di 1 immagine orizzontale con didascalia

49. InstragramFeed
Real Use Case Scenario
(https://github.com/ideatosrl/instagram-feed)
➔ Load recent media from user
➔ PSR-6 cache decorator
➔ Easily integration with Symfony

50. InstragramFeed

51. InstragramFeed

52. Questa è una diapositiva per l’inserimento di 1 immagine orizzontale con didascalia

53. InstagramCachedFeed
public function getMedia(int $count = self::MEDIA_COUNT, $maxId = null, $minId = null): array
{
$key = sprintf('instagram_feed_%s_%s_%s', $count, $maxId, $minId);
$cacheItem = $this->cache->getItem($key);
if ($cacheItem->isHit()) {
return $cacheItem->get();
}
$feed = $this->instagramFeed->getMedia($count, $maxId, $minId);
$cacheItem->set($feed);
$cacheItem->expiresAfter($this->ttl);
$this->cache->save($cacheItem);
return $feed;
}

54. Thanks!
http://joind.in/talk/2c738
Simone D’Amico
sd@ideato.it
@dymissy
github.com/dymissy

55. ?

56. We are hiring!
Catch me around here or drop us a line at recruitment@ideato.it

57. Bonus 2

58. Questa è una diapositiva per l’inserimento di 1 immagine orizzontale con didascalia

59. References
https://www.slideshare.net/andreromcke/symfony-meetup-psr6-symfony-31-cache-component
http://www.php-fig.org/psr/psr-6/
http://www.php-fig.org/psr/psr-16/
https://symfony.com/doc/current/components/cache.html
https://github.com/ideatosrl/instagram-feed

60. Image Credits
http://cybersport.gg/45530/refreshed-cache-in-new-csgo-patch/
https://www.brainvire.com/symfony2-framework-development-services