Why do we need Service Providers?

This puzzled me for a while, until I read this:

Make an Interface.

namespace App\Helpers\Contracts;

Interface RocketShipContract
{

    public function blastOff();

}

Make a Concrete Class (which implements the interface).

use App\Helpers\Contracts\RocketShipContract;

class RocketShip implements RocketShipContract
{

    public function blastOff()
    {

        return 'Houston, we have ignition';

    }

}

Create a Service Provider

php artisan make:provider RocketShipServiceProvider

Use this to bind the concrete class to the interface:

    public function register()
    {
        $this->app->bind('App\Helpers\Contracts\RocketShipContract', function(){

            return new RocketShip();

        });
    }

Using The Rocketship.

public function index(RocketShipContract $rocketship)

We have type hinted the interface but this will create an instance of the concrete class. This is because of the binding in the service provider.

Why Do This?

Makes it easy to swap a different concrete class in, just by swapping the binding.

Cool.