[🔥] onDisconnect not doing anything

[pierroo]

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Issue

I am trying to build a presence system following the docs. very simply I have the following:

const amOnline = database().ref(`.info/connected`)
    const presenceRef = database().ref(`users/${user.uid}/watchers`)
    amOnline.on('value', (snapshot) => {
      if (snapshot.val()) {
        console.log('connected val: ', snapshot.val())
        presenceRef.onDisconnect().update({ isOnline: false })
      } else {
        console.log('COMING OFFLINE')
      }
    });

I can clearly see the "connected val: true" in my console.log; but the onDisconnect() update is NEVER called (trying to force close the app, close properly, close internet, etc) Also, the else "coming offline" log is also never triggered.

I am using firebase for years, everything else is working fine, so it's really just the onDisconnect that seems void. I'm trying on an emulator (again, every other firebase implementation, database accesses / updates / etc work fine)

• Platform that you're experiencing the issue on:
  • [ ] iOS
  • [x ] Android
  • [ ] iOS but have not tested behavior on Android
  • [ x] Android but have not tested behavior on iOS
  • [ ] Both
• react-native-firebase version you're using that has this issue:
  • 14.9.1
• Firebase module(s) you're using that has the issue:
  • firebase database
• Are you using TypeScript?
  • No

[mikehardy]

I observed a lot of flaky behavior myself in the .info/connected node, you can see I had to xit (vs it, in our testing library mocha's terminology xit means cross that test out temporarily)

https://github.com/invertase/react-native-firebase/blob/main/packages/database/e2e/internal/connected.e2e.js

I had success with simply running onDisconnect handlers though, perhaps that is a sufficient building block to build the presence system, if the style is adapted somewhat? Here's the enabled test that passes every CI run, nice and stable:

https://github.com/invertase/react-native-firebase/blob/ee740f80501fdd2ea5184515c4840340fca55e63/packages/database/e2e/onDisconnect/set.e2e.js#L67-L78

We document doing a presence system based on onDisconnect though, so I think it will be sufficient? https://rnfirebase.io/database/presence-detection

[pierroo]

Thank you @mikehardy for answering.

I tried with your suggestion, using onDisconnect() on my presence ref as follow:

const checkPresence = useCallback(async() => {
const presenceRef = database().ref(`users/${user.uid}/watchers`)
    setTimeout(() => {
      console.log('GOING OFFLINE')
      database().goOffline()
    }, 1500)
    await presenceRef.onDisconnect().update({ isOnline: false })}
}, [])

But unfortunately no success yet. When I restart my emulator, or when the timeout triggers the "goOffline()", the users/uid/watchers/isOnline doesn't get updated.

Did I misunderstand something from your answer?

Also, do we really need the await onDisconnect?

[mikehardy]

Your code differs from our docs. It might be valid or it might not.

Please make an app.js that uses our example code exactly as a minimal viable reproduction. Make a button that goes offline and online and a text in a view that prints status.

[pierroo]

Sorry I should have mentioned I did try the code from your doc as follow:

const reference = database().ref(`/users/${user.uid}/watchers/isOnline`);
    reference.set(true).then(() => console.log('Online presence set'));

    // Remove the node whenever the client disconnects
    reference
      .onDisconnect()
      .remove()
      .then(() => console.log('On disconnect function configured.'));

set(true) gets triggered as expected; but the onDisconnect() never does; it litterally does nothing and never gets triggered, even with a button and goOffline()

it should be working on an emulator as well, right?

[mikehardy]

Our e2e test harness runs on emulators, you can see our harness setup in .github/workflows here, it's all open, every single line of source and infrastructure for the whole project

You keep showing snippets - https://stackoverflow.com/help/mcve

Please make an app.js that uses our example code exactly as a minimal viable reproduction. Make a button that goes offline and online and a text in a view that prints status.

Also you hacked up our issue template and did not provide all the info we ask for, perhaps forgivable but it decreases quality of support. https://stackoverflow.com/help/how-to-ask

If there were an app.js I could perhaps drop it in our test project and examine. But I can't really help when just tossing snippets around with assertions of not working and no full spec of test environment or versions etc.

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