Presentation

Chapter 12

What's Caching?

Storing a response into a file and using it for future

Both on client and server

Symfony's solution

Cache of an action (with or without the layout)
Cache of a partial, a component, or a component slot
Cache of a template fragment

You need to first enable caching in settings.yml

dev:
.settings:
cache: on

Frontend/modules/user/config/cache.yml
module: user action:list

list:
enabled: on
with_layout: false # Default value
lifetime: 86400 # Default value

A complete one

list:
enabled: on
show:
enabled: on

all:
with_layout: false # Default value
lifetime: 86400 # Default value

Even arguments can be handled by cache
Actions called with a POST method or with GET parameters are not cached.

Partial, Component, Slots or Component Slots

Same

frontend/modules/user/config/cache.yml

_my_partial:
enabled: on
list:
enabled: on
...

It can handle parameters as well.

<?php include_partial('user/my_other_partial', array('foo' => 'bar')) ?>

Components

_day:
enabled: on

Template dependent or not?

_day:
contextual: true
enabled: on

part of a template

Example

<?php echo link_to('last accessed user', 'user/show?id='.$last_accessed_user_id) ?>


<?php if (!cache('users')): ?>
<?php foreach ($users as $user): ?>
<?php echo $user->getName() ?>
<?php endforeach; ?>
<?php cache_save() ?>
<?php endif; ?>

Or...

<?php if (!cache('users', 43200)): ?>

$context->getViewCacheManager()->addCache('article', 'show', array(
'withLayout' => true,
'lifeTime' => 3600,
));

frontend/lib/conditionalCacheFilter.class.php

class conditionalCacheFilter extends sfFilter
{
public function execute($filterChain)
{
$context = $this->getContext();
if (!$context->getUser()->isAuthenticated())
{
foreach ($this->getParameter('pages') as $page)
{
$context->getViewCacheManager()->addCache($page['module'], $page['action'], array('lifeTime' => 86400));
}
}

// Execute next filter
$filterChain->execute();
}
}

filters.yml

...
security: ~

conditionalCache:
class: conditionalCacheFilter
param:
pages:
- { module: article, action: show }

cache: ~
...

Where to store?

factories.yml

view_cache:
class: sfFileCache
param:
automaticCleaningFactor: 0
cacheDir: %SF_TEMPLATE_CACHE_DIR%

You can also use apache-level caching for super-fast caching

The entire cache

// Erase the whole cache
> php symfony cache:clear

// Short syntax
> php symfony cc

// Erase only the cache of the frontend application
> php symfony cache:clear --app=frontend

// Erase only the HTML cache of the frontend application
> php symfony cache:clear --app=frontend --type=template

// Erase only the configuration cache of the frontend application
// The built-types are config, i18n, routing, and template.
> php symfony cache:clear --app=frontend --type=config

// Erase only the configuration cache of the frontend application and the prod environment
> php symfony cache:clear --app=frontend --type=config --env=prod

Selective Parts

public function executeUpdate($request)
{
// Update a user
$user_id = $request->getParameter('id');
$user = UserPeer::retrieveByPk($user_id);
$this->forward404Unless($user);
$user->setName($request->getParameter('name'));
...
$user->save();

// Clear the cache for actions related to this user
$cacheManager = $this->getContext()->getViewCacheManager();
$cacheManager->remove('user/list');
$cacheManager->remove('user/show?id='.$user_id);
...
}

Remove Partials

sf_cache_key is hard to memorize! Instead, define your own cache key:

<? include_partial('a1partial', array('i' => $i, 'sf_cache_key'=>$i)) ?>
...
<?php include_partial('user/my_partial', array(
'user' => $user,
'sf_cache_key' => $user->getId()
) ?>

and remove it

$cacheManager->remove('@sf_cache_partial?module=user&action=_my_partial&sf_cache_key='.$user->getId());

Removing Template Fragments

<?php if (!cache('users')): ?>
... // Whatever
<?php cache_save() ?>
<?php endif; ?>

// Is identified in the cache as
@sf_cache_partial?module=user&action=list&sf_cache_key=users

// Clear it with
$cacheManager->remove('@sf_cache_partial?module=user&action=list&sf_cache_key=users');

Cache dependencies

You need to be aware of caching problems.

Several Clearings at once

$cacheManager->remove('user/show?id=*'); // Remove for all user records

$cache->remove('user/show?sf_culture=*&id=12');

$cacheManager->remove('@sf_cache_partial?module=user&action=_my_partial&sf_cache_key=*'); // Remove for all keys

Specify host

$cacheManager->remove('user/show?id=*'); // Remove records for the current host and all users
$cacheManager->remove('user/show?id=*', 'life.askeet.com'); // Remove records for the host life.askeet.com and all users
$cacheManager->remove('user/show?id=*', '*'); // Remove records for every host and all users

Removing frontend cache from backend

$frontend_cache_dir = sfConfig::get('sf_cache_dir').DIRECTORY_SEPARATOR.'frontend'.DIRECTORY_SEPARATOR.sfConfig::get('sf_environment').DIRECTORY_SEPARATOR.'template';
$cache = new sfFileCache(array('cache_dir' => $frontend_cache_dir)); // Use the same settings as the ones defined in the frontend factories.yml
$cache->removePattern('user/show?id=12');

ETag

send as HTTP header, helps server to see if the content is modified, etc.

enbale it in symfony

all:
.settings:
etag: on

Last modified time

Server:

Last-Modified: Sat, 23 Nov 2006 13:27:31 GMT

Set it in symfony:

$this->getResponse()->setHttpHeader('Last-Modified', $this->getResponse()->getDate($timestamp));

Browser:

If-Modified-Since: Sat, 23 Nov 2006 13:27:31 GMT

Vary

Vary: Cookie

Symfony then caches depending on different parameters:

$this->getResponse()->addVaryHttpHeader('Cookie');
$this->getResponse()->addVaryHttpHeader('User-Agent');
$this->getResponse()->addVaryHttpHeader('Accept-Language');