iOS：如何在上传时检查FTP服务器上是否已存在目录？

Question

I am working on an App, in which I want to upload images and pdf to the FTP server. I am using this reference ref .All is working good. The images and pdf are getting uploaded on the server with proper names and sizes.

But, now I want to check if the directory is already exists on the server or not. I am not able to get it to work with this library.

So my question is that how to check directory on ftp,if directory is there then upload the files if not then first create directory on ftp and then upload files onto that directory?

Any Ideas.. ? Any help will be appreciated.

Answer 1

Different FTP servers will answer the LIST request in differing ways, so there is no single answer to this question. RFC959 says on the matter:

Since the information on a file may vary widely from system
to system, this information may be hard to use automatically
in a program, but may be quite useful to a human user.

Using the CWD request to change into the directory in question, and detecting a successful response will detect the directory, however that leaves you in that directory as a potentially unrequired side effect.

For these reasons, as well as others, you may find more modern protocols such as SSH (which includes a file transfer feature) to be more useful. You may find the DLSFTPClient CocoaPod useful.

M.