user_context
This chapter describes how to configure user context caching. See the User Context Feature chapter for an introduction to the subject.
Configuration
Caching Proxy Configuration
Varnish
Set up Varnish caching proxy as explained in the user context documentation.
Symfony reverse proxy
Set up Symfony reverse proxy as explained in the Symfony HttpCache documentation.
Context Hash Route
Then add the route you specified in the hash lookup request to the Symfony routing configuration, so that the user context event subscriber can get triggered:
# app/config/routing.yml
user_context_hash:
path: /_fos_user_context_hash
Important
If you are using Symfony security for the hash generation, make sure that this route is inside the firewall for which you are doing the cache groups.
Note
This route is never actually used, as the context event subscriber will act before a controller would be called. But the user context is handled only after security happened. Security in turn only happens after the routing. If the routing does not find a route, the request is aborted with a ‘not found’ error and the listener is never triggered.
The event subscriber has priority 7
which makes it act right after the
security listener which has priority 8
. The reason to use a listener
here rather than a controller is that many expensive operations happen
later in the handling of the request. Having this listener avoids those.
enabled
type: enum
default: auto
options: true
, false
, auto
Set to true
to explicitly enable the subscriber. The subscriber is
automatically enabled if you configure any of the user_context
options.
# app/config/config.yml
fos_http_cache:
user_context:
enabled: true
hash_header
type: string
default: X-User-Context-Hash
The name of the HTTP header that the event subscriber will store the context hash in when responding to hash requests. Every other response will vary on this header.
match
accept
type: string
default: application/vnd.fos.user-context-hash
HTTP Accept header that hash requests use to get the context hash. This must correspond to your caching proxy configuration.
method
type: string
HTTP method used by context hash requests, most probably either GET
or
HEAD
. This must correspond to your caching proxy configuration.
matcher_service
type: string
default: fos_http_cache.user_context.request_matcher
Id of a service that determines whether a request is a context hash request.
The service must implement Symfony\Component\HttpFoundation\RequestMatcherInterface
.
If set, accept
and method
will be ignored.
hash_cache_ttl
type: integer
default: 0
Time in seconds that context hash responses will be cached. Value 0
means
caching is disabled. For performance reasons, it makes sense to cache the hash
generation response; after all, each content request may trigger a hash
request. However, when you decide to cache hash responses, you must invalidate
them when the user context changes, particularly when the user logs in or out.
This bundle provides a logout handler that takes care of this for you.
always_vary_on_context_hash
type: boolean
default: true
This bundle automatically adds the Vary header for the user context hash, so you don’t need to do this yourself or configure it as header. If the hash header is missing from a request for some reason, the response is set to vary on the user identifier headers to avoid problems.
If not all your pages depend on the hash, you can set
always_vary_on_context_hash
to false
and handle the Vary yourself.
When doing that, you have to be careful to set the Vary header whenever needed,
or you will end up with mixed up caches.
logout_handler
The logout handler will invalidate any cached user hashes when the user logs out. This will make sure that the session cookie of the logged out session can not be abused to see protected cached content.
For the handler to work:
your caching proxy must be configured for tag invalidation
Symfony’s default behavior of regenerating the session id when users log in and out must be enabled (
invalidate_session
).
Warning
The cache invalidation on logout only works correctly with FOSHttpCacheBundle 2.2 and later. It was broken in older versions of the bundle.
Tip
The logout handler is active on all firewalls. If your application has
multiple firewalls with different user context, you need to create your own
custom invalidation handler. Be aware that Symfony’s LogoutSuccessHandler
places the SessionLogoutHandler
that invalidates the old session
before any configured logout handlers.
enabled
type: enum
default: auto
options: true
, false
, auto
Defaults to auto
, which enables the logout handler service if a
proxy client is configured.
Set to true
to explicitly enable the logout handler. This will throw an
exception if no proxy client is configured.
user_identifier_headers
type: array
default: ['Cookie', 'Authorization']
Determines which HTTP request headers the context hash responses will vary on.
If the hash only depends on the Authorization
header and should be cached
for 15 minutes, configure:
# app/config/config.yml
fos_http_cache:
user_context:
user_identifier_headers:
- Authorization
hash_cache_ttl: 900
The Cookie
header is automatically added to this list unless session_name_prefix
is set to false
.
session_name_prefix
type: string
default: PHPSESSID
Defines which cookie is the session cookie. Normal cookies will be ignored in user context and only the session cookie is taken into account. It is recommended that you clean up the cookie header to avoid any other cookies in your requests.
If you set this configuration to false
, cookies are completely ignored. If
you add the Cookie
header to user_identifier_headers
, any cookie will
make the request not anonymous.
role_provider
type: boolean
default: false
One of the most common scenarios is to differentiate the content based on the
roles of the user. Set role_provider
to true
to determine the hash from
the user’s roles. If there is a security context that can provide the roles,
all roles are added to the hash:
# app/config/config.yml
fos_http_cache
user_context:
role_provider: true
Custom Context Providers
Custom providers need to:
implement the
FOS\HttpCache\UserContext\ContextProvider
interfacebe tagged with
fos_http_cache.user_context_provider
.
New in version 2.4.0: Since version 2.4.0, context providers are autoconfigured. With autoconfigure enabled in Symfony 3.3 and newer, your custom providers are tagged automatically, with a default priority of 0. For older versions, or if autoconfigure is disabled, or to override the priority, check out the rest of this section.
If you need context providers to run in a specific order, you can specify the
optional priority
parameter for the tag. The higher the priority, the
earlier a context provider is executed. The build-in provider has a priority
of 0.
The updateUserContext(UserContext $context)
method of the context provider
is called when the hash is generated.
acme.demo_bundle.my_service:
class: "%acme.demo_bundle.my_service.class%"
tags:
- { name: fos_http_cache.user_context_provider, priority: 10 }
<service id="acme.demo_bundle.my_service" class="%acme.demo_bundle.my_service.class%">
<tag name="fos_http_cache.user_context_provider" priority="10" />
</service>
$container
->register('acme.demo_bundle.my_service', '%acme.demo_bundle.my_service.class%')
->addTag('fos_http_cache.user_context_provider', array('priority' => 10))
;