Allows read access to existing files and creation of new files via FTP. If the server does not support passive mode ftp, the connection will fail.

You can open files for either reading or writing, but not both simultaneously. If the remote file already exists on the ftp server and you attempt to open it for writing but have not specified the context option overwrite, the connection will fail. If you need to overwrite existing files over ftp, specify the overwrite option in the context and open the file for writing. Alternatively, you can use the FTP extension.

Appending: As of PHP 5.0.0 files may be appended via the ftp:// URL wrapper. In prior versions, attempting to append to a file via ftp:// will result in failure.