$request->file()始終返回null
<form action="http://127.0.0.1:8787/v1/upload/file" method="post" enctype="multipart/form-data">
<input type="file" name="file">
<button type="submit">GO</button>
</form>
public function upload(Request $request)
{
return $this->success($request->file());
}