How can a desktop application installed on multiple PCs be synced?

Question

We have developed a desktop application using Python. The scenario is:

1. An internet connection is not available.
2. The desktop application would be installed in multiple PCs
3. PC1 would enter data to a particular section (other PCs, (like PC2, PC3, etc.) can't input their respective sections unless PC1 enters their respective section).

When PC1 enters data on their section, we want it to be reflected on every other PC that has the desktop application installed.

1. How can we sync data within multiple desktop applications where there is no internet connectivity?
2. If we can achieve this using a local LAN, then how can we do this?

Answer 1

The most common solution would be to have one machine act as the server. Each other machine would pass its data back to the server machine over the local network. The other client machines would be notified by the server that changes had been made. The server would control and store all the data.

You could either write a separate server application to run on a completely different machine, or you could have one of your client machines act as the 'host' and take on the server role itself.

Alternatively, you could work on a peer-to-peer solution, where each machine has a separate but synchronised copy of the data. That sounds harder to get right, to me.

One of the answers at Python Library/Framework for writing P2P applications recommends the Twisted framework for network applications.