In this presentation, I show the audience how to implement HTTP caching best practices in a non-intrusive way in PHP Symfony 4 code base.
This presentation focuses on topics like:
- Caching using cache-control headers
- Cache variations using the Vary header
- Conditional requests using headers like ETag & If-None-Match
- ESI discovery & parsing using headers like Surrogate-Capability & Surrogate-Control
- Caching stateful content using JSON Web Token Validation in Varnish
More information about this presentation is available at https://feryn.eu/speaking/developing-cacheable-php-applications-php-limburg-be/
21. ✓Stateless
✓Well-defined TTL
✓Cache / no-cache per resource
✓Cache variations
✓Conditional requests
✓HTTP fragments for non-
cacheable content
In an ideal world
35. <?php
namespace AppController;
use SymfonyComponentHttpFoundationRequest;
use SensioBundleFrameworkExtraBundleConfigurationRoute;
use SymfonyBundleFrameworkBundleControllerController;
class DefaultController extends Controller
{
/**
* @Route("/", name="home")
*/
public function index()
{
return $this->render('index.twig');
}
}
src/Controller/DefaultController.php
37. {% extends "base.twig" %}
{% block title %}Home{% endblock %}
{% block content %}
<div class="page-header">
<h1>{{ 'example' | trans }}</h1>
</div>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris consequat orci
eget libero sollicitudin, non ultrices turpis mollis. Aliquam sit amet tempus elit.
Ut viverra risus enim, ut venenatis justo accumsan nec. Praesent a dolor tellus.
Maecenas non mauris leo. Pellentesque lobortis turpis at dapibus laoreet. Mauris
rhoncus nulla et urna mollis, et lobortis magna ornare. Etiam et sapien consequat,
egestas felis sit amet, dignissim enim.</p>
<p>Quisque quis mollis justo, imperdiet fermentum velit. Aliquam nulla justo,
consectetur et diam non, luctus commodo metus. Vestibulum fermentum efficitur nulla
non luctus. Nunc lorem nunc, mollis id efficitur et, aliquet sit amet ante. Sed
ipsum turpis, vehicula eu semper eu, malesuada eget leo. Vestibulum venenatis dui
id pulvinar suscipit. Etiam nec massa pharetra justo pharetra dignissim quis non
magna. Integer id convallis lectus. Nam non ullamcorper metus. Ut vestibulum ex ut
massa posuere tincidunt. Vestibulum hendrerit neque id lorem rhoncus aliquam. Duis
a facilisis metus, a faucibus nulla.</p>
{% endblock %}
templates/index.twig
40. home: Home
welcome : Welcome to the site
rendered : Rendered at %date%
example : An example page
log_in : Log in
login : Login
log_out : Log out
username : Username
password : Password
private : Private
privatetext : Looks like some very private data
translations/messages.en.yml
41. home: Start
welcome : Welkom op de site
rendered : Samengesteld op %date%
example : Een voorbeeldpagina
log_in : Inloggen
login : Login
log_out : Uitloggen
username : Gebruikersnaam
password : Wachtwoord
private : Privé
privatetext : Deze tekst ziet er vrij privé uit
translations/messages.nl.yml
42. <?php
namespace AppEventListener;
use SymfonyComponentHttpKernelEventGetResponseEvent;
class LocaleListener
{
public function onKernelRequest(GetResponseEvent $event)
{
$request = $event->getRequest();
$preferredLanguage = $request->getPreferredLanguage();
if(null !== $preferredLanguage) {
$request->setLocale($preferredLanguage);
}
}
}
src/EventListener/LocaleListener.php
60. <?php
namespace AppEventListener;
use SymfonyBridgeMonologLogger;
use SymfonyComponentHttpFoundationResponse;
use SymfonyComponentHttpFoundationRequest;
use SymfonyComponentHttpKernelEventGetResponseEvent;
use SymfonyComponentHttpKernelEventFilterResponseEvent;
use SymfonyBundlesRedisBundleRedisClient as RedisClient;
class ConditionalRequestListener
{
protected $redis;
protected $logger;
public function __construct(RedisClient $redis)
{
$this->redis = $redis;
}
protected function isModified(Request $request, $etag)
{
if ($etags = $request->getETags()) {
return in_array($etag, $etags) || in_array('*', $etags);
}
return true;
}
...
src/EventListener/ConditionalRequestListener.php
73. ✓ Server-side
✓ Standardized
✓ Processed on the
“edge”, no in the
browser
✓ Generally faster
Edge-Side Includes
- Sequential
- One fails, all fail
- Limited
implementation in
Varnish
74. ✓ Client-side
✓ Common knowledge
✓ Parallel processing
✓ Graceful
degradation
AJAX
- Processed by the
browser
- Extra roundtrips
- Somewhat slower