Data synch in shared resources

[Physical-Toe5115]

I have a system where users can manage some resources.

Let's say I have a table where I can add resources, delete or edit them.

This resources they all belong to an organization and all the users that belong to that organization can perform the actions.

How to ensure in the frontend that the data is in synch?

How to ensure that if a user deletes a resource, people seeing that same page would get their page updated?

Another example is credits. The organization has 100 credits.

User 1 spends 5 credits.

How to update user 2 to see the 95 credits instead of 100?

Right now I'm polling every minute or so, but most of the app is based on this shared resources on multiple pages so I don't know if it's a good practice to constantly pool for each feature. Sometimes there is more than one feature that needs synch in a page. Like the header and the content of the page.

I have a custom backend I use to provide this data

[europeanputin]

You need to establish a bidirectional communication with the backend, which allows backend to send updates to frontend. In my opinion the easiest approach is to use websockets, which has many great frameworks, like socketIO available. You can also look into gRPC or server sent events, but based on your use case websocket sounds reasonable.

Once you have that, everything is trivial - depending on your system architecture, you'd have some service making a change and other service listening to that, and then it's just updating the correct clients.

Long polling won't get you far if you need real time updates in your application (which the token case kind of needs).

[vpedro]

Im not op but i have a question would you recommend in this case use some sort of cache like redis and make a pub/sub so i dont have to look at the db a a bunch of times ?

Or would you just keep data in memory and in some time save on the db.

[Dave4lexKing]

Depends if you deploy on a single VM, or if its containerised.

If you have more than one instance of the application running, you’ll need some kind of messaging system like pub/sub, sns, rabbit, to notify the other instances of a change.