Service container¶

Introduction¶

The service container is a registry that can be used to retrieve an instance of a class which implements a desired feature, without hardcoding the class name.

To accomplish this, the container uses "service providers," each of which give the container a list of classes and identify the features that those classes implement.

You can retrieve the application's global service container using the app() global helper function. You can also create your own containers for smaller use cases.

Registering providers¶

The framework automatically registers providers that are listed in the config/providers.php file. Extensions can also configure a list of their own providers to register.

To register a provider manually, the register() method is used.

app()->register(new CustomServiceProvider());

Resolving instances¶

Resolving singletons¶

The service container allows you to resolve a single class instance from a particular type, called a singleton. This is the most common method of resolution. If multiple providers are offering instances for the requested type, only the last-registered instance will be resolved.

You can use the make() method on a container to make a single instance of a target type.

$instance = app()->make('App\Dependency');

If you're only using the global service container, then the resolve() helper function is available as a convenient shortcut.

$instance = resolve('App\Dependency');

Resolving collections¶

In some cases, you'll want to retrieve all instances of a target type, from all of the providers that have registered it across the application.

The application uses this strategy to load a number of core components, including extensions, views, and translations. It's a great way to load dynamic objects that might come from the user.

You can use the all() method on a container to retrieve a ServiceObjectCollection, which holds a list of all resolved objects.

$collection = app()->all('App\Dependency');

$instances = $collection->all(); // Get an array of instances
$first = $collection->first(); // Get the first instance

while ($instance = $collection->next()) // Iterate using next()
foreach ($collection as $instance) // Iterate using foreach()