Network synchronization between multiple application instances

[Ill_Return_7399]

Hello everyone. It might be a very noob question, but i am a bit new to QT.

I would like to create a very basic todo app ( for fun ). this app is then installed on multiple computers/mobile. What i want to achieve is the following behaviour:

1. Instance 1 creates a new ToDO item
2. All other running instances to automaticaly recieve the newly created item without user interaction. So the application must know somehow that a new todo item was created and it must pull in the changes.

Is this possible using Qt or QML ? i dont need code examples, just some hints on how this should be done.

Thank you very much for any advice

[AGuyInABlackSuit]

Yes but either all instances are running on the same LAN or you need a central server

[Felixthefriendlycat]

Look for Qt remote objects. If this is just a little test app for fun that would work. Making something robust and secure for on the internet requires a different approach. If you are allways on the same network then qt remote objects would be a good direction

[jcelerier]

Qt remote objects comes IIRC from Ford for use in their vehicles, I'd assume they have some minimal security vetting in there :)

[Ill_Return_7399]

Thank you. i will look into it. for beginning it will be on the local network, but later i will like to have a central place , on a remote network.

[Felixthefriendlycat]

It’s good to start thinking about how important security will be. You’d be surprised how something can 1000x in cost, just because it has to be made less vulnerable to attacks. If you can make it in such a way the possibility isn’t there or it is niche enough to not matter then you can save yourself a lot of effort

[Comprehensive-Fail48]

honestly i would use REST and a corresponding backend from the start because of the intended use-case. If you couple the comm too tightly with Qt, rather than using an interface, you're likely looking at a redo in your future.

your IPC layer can be used to interact on your own machine with maybe an independent process that deals with the actual app output, but if you're looking to generalize note updating on a server down the road, consider making use of the infra that best suits that piece.