Understand Basic Of Laravel Contracts

Introduction:

• Creator of Laravel, Taylor Otwell brings awesome features in Laravel 5 called Contracts.
• Contracts are a set of interfaces which helps a developer to make code loosely coupled base OR in another term we can say Contracts are interfaces that provide core services.
• So in common, Laravel Contracts is a wrapper of different interfaces that property of `illuminate/contracts`.

Now what are the 'Facades'?:

Facades also interface and like a Contracts so let's first understand what are the Facades.

• Do they have any similarity or relationship or anything else? Let's understand something about Facades first.
• Facades are also static interfaces that provide access methods to the classes of service container. 
• We can use Facades `type­hint` like we already implement the route.

Route::bind('mystore', function ($id){
	return App\Store::get();
});

In above code, Facades solved the contracts out of service container. But the quality of Contracts is we can define conspicuous dependencies for your classes and make your application more loosely coupled. Here Facades work fine but in some case, we want to create something extra, you need to use Contracts.

How to write?

Contracts implementation is very simple. Let's understand the Contracts implementation with sample example:

Suppose I have a 'StoreController' with that I will maintain my all store list and for that, I need insert these data into the database. So what I will do, I'll create an eloquent model 'Store' and bind it with a route into route.php.

After that, I will use that model 'Store' all CRUD operations using the resource. In between, first I check whether the user is logged in OR not? If logged in then only can able act on model CRUD otherwise not. Example code:

public function insert(Request $request)
{
 	if (Auth::check()) {
   	 // If user is logged in...
    }
}

From above code, I used Facades `Auth` to check the user is logged in OR not? So here if I don't want more decoupled state it works fine and it's what? code with SOLID principle and here Contracts comes for the solution. For that what I do? just inject 'Auth' Facade through constructor:

use Illuminate\Http\Request;
use App\Http\Requests;
use App\Http\Controllers\Controller;
use Illuminate\Contracts\Auth\Guard as Auth;

class StoreController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return Response
     */
    protected $auth;
    public function __construct(Auth $auth) {//Inject `Auth` Facade...
    	$this­->auth = $auth;  	 
    }

    public function insert(Request $request)
    {
    	$this­->auth­->attempt();	 
    }
}