subscriptions | Grounded intelligent subscriptions - WIP

In general I like to use observables lazily... If you had a service which looked like:

You can filter with:

Here is a little example that I wrote which will hopefully give you some insight on how you can fix yours, as I don't really know your GridView setup. Though potentially just adding document.ready() to your ShowStatus() might fix this issue.

Front-End

Out of the box, there's no functionality you're asking for. You will need to write custom code to achieve that. You could also raise a feature request with the broker team.

I fixed the issue with react not re-rendering when the state is updated via webhook. The primary problem was this line:

const [posts, setPosts] = useState(props.posts || []);

I changed that line to this:

const [posts, setPosts] = useState([]);

With that change this two approached updated the state with a re-render & broadcast of the state change via websockets to other open tabs.

Approach 1:

Instead of using the dunder methods __setattr__/__getattr__ (or __getattribute__), you should use getattr(self, client) and setattr(self, client, value)...

but better yet, you should just use a dict if you need to map names to objects.

It appears that the option you'll want to use to target the WS connect/disconnect event is connectionCallback (see full list of WebSocketLink options here).

Take a look at lines 620-635 of the WebSocketLink source and you can see that the provided connectionCallback is called both for GQL_CONNECTION_ERROR and GQL_CONNECTION_ACK received message types. Therefore, you should be able to target both events using this callback.

I haven't used Apollo's WebSocketLink yet myself, so I am unable to confirm that this will work fully as expected. Additionally, the behavior to fetch all missing chat messages upon reconnect is something you may need to build yourself as it doesn't appear to be part of the default reconnect behavior (will depend on server implementation; see Apollo Server docs). Conversely, it does appear that WebSocketLink will forward all unsent messages to the server upon reconnect by default.

Keeping the whole discussion aside of LiveData vs SharedFlow or StateFlow. Coming onto ViewModels as you asked. If we are to go by documentation

The ViewModel class is designed to store and manage UI-related data in a lifecycle conscious way. The ViewModel class allows data to survive configuration changes such as screen rotations.

UI controllers such as activities and fragments are primarily intended to display UI data, react to user actions, or handle operating system communication, such as permission requests. Requiring UI controllers to also be responsible for loading data from a database or network adds bloat to the class. Assigning excessive responsibility to UI controllers can result in a single class that tries to handle all of an app's work by itself, instead of delegating work to other classes. Assigning excessive responsibility to the UI controllers in this way also makes testing a lot harder.

It's easier and more efficient to separate out view data ownership from UI controller logic.

I guess this sums it up quite well. It is true that lifeCycleScope can eliminate the need of ViewModel in a way, but ViewModel does more than just being a holder for LiveData.

Even if you want to use SharedFlow or StateFlow over LiveData I would suggest you still make use of ViewModel and inside it use a viewModelScope instead to still perform the usual and required separation of concerns between UI and data.

The problem is that your publisher is too artificially crude: it is not asynchronous. An array publisher just publishes all its values at once, so you are canceling too late; and you are blocking the main thread. Use something like a timer publisher instead, or use a flatmap with a delay and backpressure.