Reverse Proxy Caching with Symfony 

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Agenda Revisit traditional caching strategies See how Symfony is different 

There are several caching strategies 

Output cache 

$cache = Zend_Cache::factory(
 'Output',
 'Apc', [
 'lifetime' => 7200,
 'automatic_serialization' => true
 ]
 ); 

if (!($cache->start('mypage'))) { // output everything as usual echo 'Hello world! '; echo 'This is cached (' .time() . ') '; $cache->end(); // output buffering ends } echo 'This is never cached (' .time() . ').'; 

Function cache 

$cache = Zend_Cache::factory(
 'Function',
 'Apc', [
 'lifetime' => 7200,
 'automatic_serialization' => true, 'cached_functions' => [ 'similar_text' ]
 ]
 ); 

$cache->call(
 'similar_text',
 [
 'a really long string ...',
 'another really long string ...'
 ]
 ); 

Class cache 

$cache = Zend_Cache::factory(
 'Class',
 'Apc', [
 'lifetime' => 7200,
 'automatic_serialization' => true, 'cached_entity' => $anInstance
 ]
 ); 

$cache->anExpensiveMethodCall(); 

Full page cache 

$cache = Zend_Cache::factory(
 'Page',
 'Apc', [
 'lifetime' => 7200,
 'automatic_serialization' => true, 'default_options' => [ 'cache_with_get_variables' => true, 'make_id_with_get_variables' => true ], 'regexps' => [ '^/index/' => ['cache' => true], '^/article/' => ['cache' => false], ] ] ); 

$cache->start(); 

But Symfony has a total different approach 

Symfony relies on the simplicity and power of the HTTP cache as defined in the HTTP Specification 

Combines the Expiration and Validation models 

// web/app.php require_once __DIR__.'/../app/bootstrap.php.cache'; require_once __DIR__.'/../app/AppKernel.php'; require_once __DIR__.'/../app/AppCache.php'; use Symfony\Component\HttpFoundation\Request; $kernel = new AppKernel('prod', false); $kernel->loadClassCache();
 // wrap the default AppKernel with the AppCache one $kernel = new AppCache($kernel); $request = Request::createFromGlobals(); $response = $kernel->handle($request); $response->send(); $kernel->terminate($request, $response); 

// app/AppCache.php use Symfony\Bundle\FrameworkBundle\HttpCache\HttpCache; class AppCache extends HttpCache { protected function getOptions() { return [ 'debug' => false, 'default_ttl' => 0, 'private_headers' => ['Authorization', 'Cookie'], 'allow_reload' => false, 'allow_revalidate' => false, 'stale_while_revalidate' => 2, 'stale_if_error' => 60, ]; } } 

Symfony provides useful abstractions to make the life easier 

Symfony\Component\HttpFoundation\Response 

$response = Response::create('response content'); 

$response->setPublic();
 $response->setPrivate(); 

$date = new DateTime(); $date->modify('+600 seconds'); $response->setExpires($date); 

$response->setMaxAge(600); $response->setSharedMaxAge(600); 

$response->setLastModified($date);
 $response->setETag(computeETag());
 // Set response as public. Otherwise it will be private by default. $response->setPublic(); if ($response->isNotModified($request)) { return $response; } 

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 
 /** * @Cache(expires="tomorrow", public=true) */ class BlogController extends Controller {
 // ... } 

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 
 /**
 * @Cache(expires="tomorrow", public=true) */ class BlogController extends Controller {
 
 /**
 * @Route("/posts/{id}")
 * @Cache(expires="+2 days")
 */
 public function showAction($id) {
 // ...
 } } 

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 
 /**
 * @Cache(expires="tomorrow", public=true) */ class BlogController extends Controller {
 
 /**
 * @Route("/posts/{id}")
 * @Cache(
 * lastModified="post.getUpdatedAt()",
 * ETag="'Post' ~ post.getId() ~ post.getUpdatedAt()"
 * )
 */
 public function showAction($id) {
 // ...
 } } 

Combining Expiration and Validation 

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 
 /**
 * @Cache(expires="tomorrow", public=true) */ class BlogController extends Controller {
 
 /**
 * @Route("/posts/{id}")
 * @Cache(
 * lastModified="post.getUpdatedAt()",
 * ETag="'Post' ~ post.getId() ~ post.getUpdatedAt()",
 * expires="+15 days"
 * )
 */
 public function showAction($id) {
 // ...
 } } 

Working with Reverse Proxy caches 

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 
 class BlogController extends Controller {
 
 /**
 * @Route("/posts/{id}")
 * @Cache(
 * lastModified="post.getUpdatedAt()",
 * ETag="'Post' ~ post.getId() ~ post.getUpdatedAt()",
 * smaxage=3600
 * )
 */
 public function showAction($id) {
 // ...
 } } 

Symfony Reverse Proxy even supports ESI 



use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 
 class BlogController extends Controller {
 
 /**
 * @Route("/posts/{id}")
 * @Cache(smaxage=3600)
 */
 public function showAction($id) {
 // ...
 } } 

{# AppBundle:Posts:show.html.twig #}
 {{ render_esi(controller('AppBundle:Comments:show', { 'id': post.id() })) }} 

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route; 
 class CommentsController extends Controller {
 /**
 * @Cache(smaxage=600) */ public function showAction($id) { // ... }
 } 

Symfony is able to know if is talking with a Reverse Proxy
 Cache like Varnish 

¡Thanks! Questions?