Answers for "class 'app\http\controllers\s3client' not found"

Class 'App\Http\Controllers\File' not found

// Class 'App\Http\Controllers\File' not found
use Illuminate\Support\Facades\File;

Class 'App\Http\Controllers\Response' not found

use Illuminate\Support\Facades\Response;
Or
use Response;

Or use full namespace:
return \Response::json(...);

Or just use helper:
return response()->json(...);