Python文件描述符打开和关闭操作，用于按块上传文件

I am working on http file upload to server. To handle large files I'm using chunk upload, where files are divided into chunks of lets say 1MB and are sent to backend server synchronously as a POST request. At back-end bottle server,I receive chunk and append it to a new file using file.write.I am working on http file upload to server. To