在laravel框架中接受inputs上傳的檔案一直報錯，詳細程式碼如下：

use Illuminate\Http\Request;
public function file(){
         $file = Request::file('photo');
         $allowed_extensions = ["png", "jpg", "gif"];
         if ($file->getClientOriginalExtension() && !in_array($file->getClientOriginalExtension(), $allowed_extensions)) {
             return ['error' => 'You may only upload png, jpg or gif.'];
         }
 
    }

報錯如下：
1、Request使用錯誤：
Non-static method Illuminate\Http\Request::file() should not be called statically, assuming $this from incompatible context
#2、getClientOriginalExtension()使用錯誤
Call to a member function getClientOriginalExtension() on string

希望大神指教，急急！ ！ ！