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SuperKernel Event

super-kernel/event declares the application lifecycle events that SuperKernel publishes, so that components and applications can act when an application starts and when a project is built.

Installation

composer require super-kernel/event

The package has no requirement beyond PHP. It only declares events: to receive them, an application also needs super-kernel/event-dispatcher, which registers listeners, and a publisher, which is super-kernel/framework for BeforeApplicationStart and skernel build for ApplicationBuild.

What it provides

• BeforeApplicationStart, published after the application is created and before it is returned to run, carrying that application.
• ApplicationBuild, published once by skernel build so that components write the artifacts a packaged application loads.

It does not:

• dispatch events or discover listeners; super-kernel/event-dispatcher does;
• decide when an event is published; the publishing package does;
• declare events for other boundaries, such as after start or at stop; an application declares its own event classes for those.

Quick start

In an application created from super-kernel/skeleton, this listener renames the console application before it runs. Save it as src/Listener/NameTheApplication.php:

<?php

declare(strict_types=1);

namespace Src\Listener;

use SuperKernel\Attribute\Listener;
use SuperKernel\Contract\ListenerInterface;
use SuperKernel\Event\BeforeApplicationStart;
use Symfony\Component\Console\Application;

#[Listener]
final readonly class NameTheApplication implements ListenerInterface
{
    public function listen(): array
    {
        return [
            BeforeApplicationStart::class,
        ];
    }

    public function process(object $event): void
    {
        assert($event instanceof BeforeApplicationStart);

        $application = $event->application();

        if ($application instanceof Application) {
            $application->setName('Billing');
        }
    }
}

Build the project and ask the application for its name:

skernel build
php bin/bootstrap.php --version

The output starts with Billing.

Public surface

Behavior to know

• Creating an event object publishes nothing and starts nothing.
• super-kernel/framework publishes BeforeApplicationStart once for each application it creates, synchronously. An exception from a listener propagates, and the application is not returned or run.
• skernel build publishes ApplicationBuild without creating or running the application. An exception from a listener fails the build.
• Listeners are discovered from the build metadata: run skernel build again after adding, removing, or changing a listener, or start with skernel run, which builds first.

Documentation

The developer documentation describes both events, more listener examples, and how the packages that publish them work together: SuperKernel Event.

License

Released under the MIT License. See LICENSE.