Laravel Middlewareでユーザーロール(権限)によってページを出し分ける方法

$ php artisan make:model Role -m

migration file: user

Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('role_id');
            $table->string('name');
            $table->string('email')->unique();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });

migration file: role

Schema::create('roles', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->timestamps();
        });

$ php artisan migrate:refresh

Model: Role.php

protected $fillable = [
    	'name'
    ];

Model: User.php

public function role(){
        return $this->belongsTo('App\Role');
    }

$ php artisan make:middleware IsAdmin

Kernel.php

protected $routeMiddleware = [
        'auth' => \App\Http\Middleware\Authenticate::class,
        'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
        'can' => \Illuminate\Foundation\Http\Middleware\Authorize::class,
        'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
        'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
        'role'=>\App\Http\Middleware\RoleMiddleware::class,
        'IsAdmin'=>\App\Http\Middleware\IsAdmin::class,
    ];

insert into roles (name) values (‘administrator’);
insert into roles (name) values (‘subscriber’);
update users set role_id=1 where id=1;

User.php

public function isAdmin(){
        if($this->role->name == 'administrator'){
            return true;
        }

        return false;
    }

Route

Route::get('/', function () {

	$user = Auth::user();

	if($user->isAdmin()){
		echo "this user is adminstrator";
	}
    // return view('welcome');
});

うまく権限の判定が上手く動いていたのを確認します

Middleware:IsAdmin.php

use Illuminate\Support\Facades\Auth;
public function handle($request, Closure $next)
    {

        $user = Auth::user();

        if($user->isAdmin()){
            return redirect()->intended('/admin');
        }

        return $next($request);
    }

Route

Route::get('/admin', 'AdminController@index');

$ php artisan make:controller AdminController

Controller:AdminController.php

class AdminController extends Controller
{
    public function __construct(){
    	$this->middleware('IsAdmin');
    }

    public function index(){
    	return "you are an administrator because you are seeing this page";
    }
}

Middleware:IsAdmin.php

use Illuminate\Support\Facades\Auth;
public function handle($request, Closure $next)
    {

        $user = Auth::user();

        if(!$user->isAdmin()){
            return redirect()->intended('/');
        }

        return $next($request);
    }

ロールを変更して、リダイレクトされるか確認します。
update users set role_id=2 where id=1;

ロールによって、表示を切り分けたいページのControllerでは、上記のように、AdminControllerで$this->middleware(‘IsAdmin’);の判定を行うか、もしくは、以下のようにルーティングでミドルウェアの判定を行います。

Route::get('/admin/user/roles', ['middleware'=>['IsAdmin',], function(){

	return "Middleware role";
}]);

出し分ける場合、Controllerで毎回if文を書くのではなく、middlewareに関数を書いて、それを読み込むのですね。
ロールを別テーブルでbelongsToとしていますが、ロールがUserテーブルの場合でも、ロジックは同じだと思います。