Contributed by
Ryan Weaver
in #22234.
In Symfony 3.3, configuring services is much simpler thanks to these new configuration options:
_defaults
: defines the default value for the public
, tags
and
autowire
options of the services defined in a given file;_instanceof
: defines the default configuration of services depending on
their classes (e.g. add the twig.extension
tag to any service that
implements Twig_ExtensionInterface
).The evolution of this simplification is the new autoconfigure
option, which
is like an automated version of _instanceof
. If enabled, this option adds
some default configuration depending on the class implemented by the service.
Let's suppose that you want to add tags automatically to your security voters:
1 2 3 4 5 6 7 8 9 | services:
_defaults:
autowire: true
_instanceof:
Symfony\Component\Security\Core\Authorization\Voter\VoterInterface:
tags: [security.voter]
AppBundle\Security\PostVoter: ~
|
Now ask yourself: if you are registering a service with a class that implements
VoterInterface
, when would you ever not want that to be tagged with
security.voter
? In other words, a service implementing VoterInterface
can only be a security voter, unless you are doing some seriously weird things.
The same example using autoconfigure
looks like this:
1 2 3 4 5 6 | services:
_defaults:
autowire: true
autoconfigure: true
AppBundle\Security\PostVoter: ~
|
This works because each enabled bundle has the opportunity to add one or more
automated _instaceof
definitions. Of course we've already enabled this for
all the common Symfony services: commands, form types, event subscribers, etc.
Whenever we introduce a new feature to automatize the configuration of services, some developers quickly discredit it for being "magic". For us, "magic" means that something happened without you explicitly asking for it. Magic is bad because it leads to WTF moments and hard-to-debug issues.
However, this feature won't work unless you explicitly include the
autoconfigure
option in your configuration file. Besides, it only applies
to the services defined in the same file where you include autoconfigure
,
so there will be no side-effects. In short, this is not magic, just automation.
What a Symfony developer should know about the framework: News, Jobs, Tweets, Events, Videos,...