Patryk Jar

Agenda

� Definition � Methodologies � Solutions �  Tips � What else can I do on my page?

Definition

Cache – a collection of data duplicating or ig ina l va lues s tored e lsewhere on a computer

wikipedia.org

Methodologies

� Whole page (use proxy) � Partial page � Database queries (example) � Re-usable objects (example)

Caching static pages

Caching database queries 1. function cachedSingleRowQuery(!2. $query, array $bind, $expiry, PDO $db, Memcached $cache!3. ) {!4. $key = 'query' . md5($query . implode(',', $bind));!5. $obj = $cache->get($key);!6. if ( ! $obj ) {!7. $result = $db->prepare($query)->execute($bind);!8. $obj = $result->fetchObject();!9. $cache->set($key, $obj, $expiry);!10. }!11. !12. return $obj;!13. }!

Cache Invalidation Strategy

�  Time expiration � Update invalidation (DVSA Project ;) ) � Pre-generation (e.g. Facebook)

Application – no cache

…

…

HTTP requests

Application – cached data

… …

cache (e.g. session)

DataStore Interface

REST API (HTTP)

Tester Application - example 1. function get($uuid)!2. {!3. $application = getApplicationFromSession();!4.!5. if (null === $application) {!6. $data = api->getTesterApplication($uuid);!7. $application = new TesterApplication($data);!8. storeInSession($application);!9. }!10. !11. return $application ;!12. }!

Solutions

� APC �  http://uk1.php.net/apc/

� Memcached �  http://memcached.org/

� HTML5 API (in web browser): �  localStorage �  sessionStorage

Tips

What else can I do on my page?

� Externalize re-usable JS and CSS � Merge and compress CSS files � Merge and compress JavaScript files � Use CSS Sprites � Use Content Delivery Network

�  https://developers.google.com/speed/libraries/

Thank you

� Qs?