Uploading to a remote server for large files with resume capability

Necessary to fill in from the device (ios) large files to the server, so that when the connection is broken do not have to load first. Web server nginx.
I understand that there are several techniques, such as:
• via FTP;
• via PUT using webdav;
• via http smaller parts.

Please advise if the best way, and what are the pitfalls in each of them.