This is a small hobby project written for the Minecraft mod OpenComputers. The goal is to provide a FTP server that can be run on an ingame computer, accessible from the internet. Because OpenComputers limitaion on internet functionality, a proxy must be used to listen on an open port.

The main server logic is written in lua for OpenOS. While most of the basic functionality is implemented, there is a lot left for it to be a standard compliant FTP server. Testing has been done using the NppFTP plugin in Notepad++ with default settings. Being able to write code for OpenComputers in Notepad++ helps a lot, not least during refactoring.

The proxy is split into two parts, one is the proxy itself, written in C#, and the other part is the OpenComputers library that is used by the FTP server. The proxy is written as a general proxy, that is, it can be used for any protocol, not just for FTP. However, it currently only allows for incoming connections, that is, it can not connect to other servers. This may get added in the future, but was not required in order to create an FTP server with the limitation that clients must request a passive data connection. It is also somewhat of a security concern: a proxy that can not connect to other servers is less useful for general uses, and thus less likely to be exploited.

It would be nice to add SSL/TLS to the FTP server, but running encryption algorithms in lua would be less than optimal. There is a Data Card added to OpenComputers that provide some encryption functions, but I have not looked into it enough to know if it is usable, or worth the trouble. It is a game after all.