从FTP下载文件(如果给定的本地文件列表中不存在) [英]Download file from FTP if it does not exist in a given list of local files
从Web服务器(HTTP / FTP)以编程方式下载文件的最佳和最安全的方法是什么? [英]What is the best and most secure way to programatically download files from a web server (HTTP/FTP)?