Advanced FTP client class: FTP client in pure PHP

This is a FTP client class written in PHP, so it does not need any special FTP extensions to work.

The class supports passive and active FTP connections. To work with active connection, there is a special sub-class that uses the PHP sockets extension.

The class can:

- Establish connections within a configured timeout value and automatically authenticate
- Output connection debug information
- Retrieve the FTP protocol features supported by the server
- Change the current directory
- Retrieve directory listings
- Parse the directory listing entry attributes
- Check whether a given file or a directory exists
- Retrieve the size of files, the files timestamp
- Choose the transfer type between ASCII and binary
- Set the permissions mask for files copied to the local server
- Send and receive files
- Resume download from a given file position offset
- Create and remove directories
- Rename, delete and change the permissions of files