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How to Make Commands Lazily Loaded
How to Make Commands Lazily Loaded¶
Note
If you are using the Symfony full-stack framework, you are probably looking for details about creating lazy commands
The traditional way of adding commands to your application is to use
add(), which expects a
Command instance as an argument.
In order to lazy-load commands, you need to register an intermediate loader
which will be responsible for returning Command instances:
1 2 3 4 5 6 7 8 9 10 11 | use App\Command\HeavyCommand;
use Symfony\Component\Console\Application;
use Symfony\Component\Console\CommandLoader\FactoryCommandLoader;
$commandLoader = new FactoryCommandLoader(array(
'app:heavy' => function () { return new HeavyCommand(); },
));
$application = new Application();
$application->setCommandLoader($commandLoader);
$application->run();
|
This way, the HeavyCommand instance will be created only when the app:heavy
command is actually called.
This example makes use of the built-in
FactoryCommandLoader class,
but the setCommandLoader()
method accepts any
CommandLoaderInterface
instance so you can use your own implementation.
Built-in Command Loaders¶
FactoryCommandLoader¶
The FactoryCommandLoader
class provides a way of getting commands lazily loaded as it takes an
array of Command factories as its only constructor argument:
1 2 3 4 5 6 | use Symfony\Component\Console\CommandLoader\FactoryCommandLoader;
$commandLoader = new FactoryCommandLoader(array(
'app:foo' => function () { return new FooCommand(); },
'app:bar' => array(BarCommand::class, 'create'),
));
|
Factories can be any PHP callable and will be executed each time
get()
is called.
ContainerCommandLoader¶
The ContainerCommandLoader
class can be used to load commands from a PSR-11 container. As such, its
constructor takes a PSR-11 ContainerInterface implementation as its first
argument and a command map as its last argument. The command map must be an array
with command names as keys and service identifiers as values:
1 2 3 4 5 6 7 8 9 10 | use Symfony\Component\Console\CommandLoader\ContainerCommandLoader;
use Symfony\Component\DependencyInjection\ContainerBuilder;
$containerBuilder = new ContainerBuilder();
$containerBuilder->register(FooCommand::class, FooCommand::class);
$containerBuilder->compile();
$commandLoader = new ContainerCommandLoader($containerBuilder, array(
'app:foo' => FooCommand::class,
));
|
Like this, executing the app:foo command will load the FooCommand service
by calling $containerBuilder->get(FooCommand::class).
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.