Laravel validation site belongs to user -

my user.php

class user extends authenticatable {     public function sites()     {         return $this->hasmany(site::class);     } } 

my site.php

class site extends model {     public function user()     {         return $this->belongsto(user::class);     } } 

my routes.php

route::resource('site', 'sitecontroller'); 

my sitecontroller.php

class sitecontroller extends controller {     public function edit(int $id)     {         $site = auth::user()->sites()->find($id);          return view('site.edit', compact('site'));     } } 

how can validate site belongs user? understand in case if site doesn't belong user, $site variable null. want more declarative way, laravel requests, because need same check in show, update, , destroy methods. cannot use laravel request, because checking this

$siteid = route::current()->param('site'); $ids = auth::user()->sites()->pluck('id')->toarray(); $result = in_array($siteid, $ids); 

can suggest how achieve goal?

since use laravel 5.2, solution route filters deprecated. instead route filter should use middleware.
app/http/middleware/restrictpermission.php

class restrictpermission {     public function handle($request, closure $next)     {         $siteid = route::current()->parameter('site');          if (!auth::user()->sites()->find($siteid)) {             abort(403);         }          return $next($request);     } } 

app/http/kernel.php

class kernel extends httpkernel {     protected $routemiddleware = [         'restrict.permission' => restrictpermission::class,     ]; } 

sitecontroller.php

class sitecontroller extends controller {     public function __construct()     {         $this->middleware('restrict.permission', ['except' => [             'index', 'create', 'store',         ]]);     }      public function edit(int $id)     {         $site = auth::user()->sites()->find($id);         return view('site.edit', compact('site'));     } }