Lean

Lean allows you to use the PHP League's Container package with auto-wiring support as the core container in Slim 3.

Install

Via Composer

$ composer require jenssegers/lean

Usage

The easiest way to start using Lean is simply creating a Jenssegers\Lean\App instance:

require 'vendor/autoload.php';

$app = new \Jenssegers\Lean\App();

$app->get('/hello/{name}', function (Request $request, Response $response, string $name) {
    return $response->write('Hello, ' . $name);
});

$app->run();

Behind the scenes, a Slim application is bootstrapped by adding all of the required Slim components to League's container.

Service Providers

Service providers give the benefit of organising your container definitions along with an increase in performance for larger applications as definitions registered within a service provider are lazily registered at the point where a service is retrieved.

To build a service provider it is as simple as extending the base service provider and defining what you would like to register.

use League\Container\ServiceProvider\AbstractServiceProvider;

class SomeServiceProvider extends AbstractServiceProvider
{
    /**
     * The provided array is a way to let the container
     * know that a service is provided by this service
     * provider. Every service that is registered via
     * this service provider must have an alias added
     * to this array or it will be ignored.
     */
    protected $provides = [
        SomeInterface::class,
    ];

    /**
     * This is where the magic happens, within the method you can
     * access the container and register or retrieve anything
     * that you need to, but remember, every alias registered
     * within this method must be declared in the `$provides` array.
     */
    public function register()
    {
        $this->getContainer()
            ->add(SomeInterface::class, SomeImplementation::class);
    }
}

To register this service provider with the container simply pass an instance of your provider or a fully qualified class name to the League\Container\Container::addServiceProvider method.

$app = new \Jenssegers\Lean\App();
$app->getContainer()->addServiceProvider(\Acme\ServiceProvider\SomeServiceProvider::class);

Read more about service providers here.

Settings

You can access Slim's internal configuration through the settings key on the container:

$app = new \Jenssegers\Lean\App();

$app->getContainer()->get('settings')['displayErrorDetails'] = true;

Alternatively, an alias is registered that allows a bit more fluent way of working with settings:

$app = new \Jenssegers\Lean\App();

$app->getContainer()->get(\Slim\Settings::class)->set('displayErrorDetails', true);

Read more about the available configuration options here.

Route arguments

By default, Lean will use method injection to pass arguments to your routes. This allows you to type-hint dependencies on method level (similar to the Laravel framework).

Route arguments will be passed as individual arguments to your method:

$app->get('/books/{id}', function (Request $request, Response $response, string $id) {
    ...
});

They are also accessible through the getAttribute method.

$app->get('/books/{id}', function (Request $request, Response $response) {
    $id = $request->getAttribute('id');
    ....
});

If you want to disable this behaviour and use the default Slim way of route arguments, you can disable this feature be setting methodInjection to false:

$app->getContainer()->get(\Slim\Settings::class)->set('methodInjection', false);

Read more about routes here.

Error Handlers

By default, Lean uses Slim's error handlers. There are different ways to implement an error handler for Slim, read more about them here.

Typically you would create a custom error handler class that looks like this:

class CustomErrorHandler
{
    public function __invoke(ServerRequestInterface $request, Response $response, Throwable $exception)
    {
        return $response->withJson([
            'error' => 'Something went wrong',
        ], 500);
    }
}

Then you overwrite the default handler by adding it to the container:

$app = new Jenssegers\Lean\App();

$app->getContainer()->share('errorHandler', function () {
    return new CustomErrorHandler();
});

Ideally, you would put this code inside a service provider. Read more about service providers above.

Testing

$ php ./vendor/bin/phpunit

License

The MIT License (MIT).