What is the best way to share real time data between multiple devices for a short time frame in IOS

Question

I have an idea for an application where I would like the following to happen:

A group of people / their devices create a sharing session --> They can set a time frame for this session (could be one hour or one day, but not long term). --> Once the session is created they will go through their day capturing the data which I want to be shared automatically between all the devices. --> At the end of the session each device will be able to choose what of the data collected they would like to keep locally on their device despite who may have collected it. --> Once each of the devices have saved what they would like, the shared storage would be removed.

What I am struggling on is the best technology for sharing the data. I would rather not have notifications each time data is shared.

I have looked at Multipeer Connectivity as a solution, where each bit of data would get sent to each device and stored locally, but the biggest drawback is the inability to maintain a session in the background, which is likely where the application would reside for the majority of the time period.

Any direction or areas to research would be greatly appreciated. Note: at least to start with I would be looking to implement this in IOS

Answer 1

I would imagine a temporary folder on a web server (kinda like shared cloud folders) would be among the better solutions to this.

1. Doesn't require physical proximity to other participant. Could be in entirely different countries and it wouldn't matter. There's however nothing stopping you from setting such a limitation anyway.
2. Would be far easier to implement tech-wise. Especially considering cross-platform support.
3. You espace many logitical problems, such as storage space on individual devies. Like What happens when participant wants to keep some data, but there's not even enough space to even see a preview of what the participant is missing out on.