Laravel 5 how to validate route parameters?

Question

For Laravel < 5.5:
The way for this is overriding all() method for CheckTokenServerRequest like so:

public function all() 
{
   $data = parent::all();
   $data['token'] = $this->route('token');
   return $data;
}

EDIT
For Laravel >= 5.5:
Above solution works in Laravel < 5.5. If you want to use it in Laravel 5.5 or above, you should use:

public function all($keys = null) 
{
   $data = parent::all($keys);
   $data['token'] = $this->route('token');
   return $data;
}

instead.