通过Laravel 5中的config进行接口的上下文绑定

Question

Lets assume I have an interface like so:

interface RepositoryInterface{
    public function getById($id);
}

This interface gets implemented by X amount of classes.

As an example:

class SqliteRepository implements RepositoryInterface{
    public function getById($id)
    {
        return $id;
    }
}

I also have a config file in the config folder(do note, this is not the database.php file, it's whole different file):

'default'  => 'sqlite',

'connections' => [
    'sqlite' => [
        'database' => env('DB_DATABASE', storage_path('database.sqlite')),
    ],

    'some_other_db' => [
        'database' => env('DB_DATABASE', storage_path('some_other_db')),
    ],
],

The connections itself can be anything. A database, an API, heck even a csv file.

The main idea behind this is that I can switch in between storage mediums simply by changing the config. Don't ask me why I'm not using the default laravel database file, it's a long story.

---

The problem:

I want to be able to inject different implementations of the RepositoryInterface into controllers based on that config file, something along the lines of this:

if(Config::get('default') == 'sqlite')
{
    // return new SqliteRepository
}

Obviously the way to go here would be Service Providers. However I'm not exactly sure how to approach this issue. I mean I could do something along the lines of this:

class RepositoryServiceProvider extends ServiceProvider
{
    public function register()
    {
        if(Config::get('storage') == 'sqlite')
        {
            $this->app->singleton(SqliteRepository::class, function ($app) {
                return new SqliteRepository(config('SqliteRepository'));
            });
        }

    }
}

But it feels a little wrong, not to mention that it gives me zero error control. I don't want to be throwing errors in the ServiceProvider. I need some sort of contextual binding or something along those lines. I have read the the documentation regarding contextual binding but it's no exactly what I'm looking for, as it refers rather to concrete implementations of classes based on what controller uses them.

I was thinking more of an abstract factory type of deal, but, again, I'm not sure how to fit into laravel's way of doing things.

Any pointing in the right direction is appreciated.

Answer 1

interface RepositoryInterface{
    public function getById();
}

...
...

class SqliteRepository implements RepositoryInterface{
    public function getById()
    {
        return 1;
    }
}

...
...

class CsvRepository implements RepositoryInterface{
    public function getById()
    {
        return 2;
    }
}

...
...

class MonkeyPooRepository implements RepositoryInterface{
    public function getById()
    {
        return 3;
    }
}

...
...

use RepositoryInterface;
class Controller {

    public function __construct( RepositoryInterface $repo ) {
        $this->repo = $repo;
    }

    public function index()
    {
        dd($this->repo->getById());
    }

}

on your app provider;

public function register()
{
    $this->app->bind( RepositoryInterface::class, env('REPOSITORY', 'MonkeyPooRepository' ) );
}

index method would return (int)3