How do I get the currently active users on backendless. I don’t mean logged in users here coz I enabled stay logged in for each users login. I need to get the currently active users and those inactive. Is this possible. If yes please help.
What’s a definition of an “active” vs. “inactive” user?
OK not to cause any confusion, and to be understood I mean how to get users that are online and offline.
Coz I will need to notify any current user all his followers that are online.
How would our backend know that your user is offline?
Yes and how to retrieve the response either online or offline.
You can make a session just like the login sessions to check for any api call and if there isn’t an api call for a certain period of time then the user is either busy or offline. Else the user is still online.
You can make a session just like the login sessions to check for any api call and if there isn’t an api call for a certain period of time then the user is either busy or offline. Else the user is still online. That my idea.
This is often handled through a presence system; when a user state changes (offline to online or away to present or active to inactive for example) the apps sets flag in the database for that user in the user table; online = true, and when they log off online = false. That way, they can stay connected but have an indicator as to their state.
Your app can watch for that change in the users table and update your app/UI accordingly as other users go online and offline.
The trouble with this design pattern is; what happens in the case of a disconnect or the user force-quits the app. In those cases the app cannot change that flag.
Firebase has a very intuitive way of handling that situation through a onDisconnect function that lives on the server. The server monitors the connection and if it’s lost will fire a pre-defined event. In that case onDisconnect could set the online flag to false for the user that disconnected.
I realize that’s not much help but it’s a very usable and reliable function that we implement throughout our Firebase backed projects.
Does such a function or capability exist in Backendless?
Backendless provides support for that functionality through real-time event handlers.
To accomplish the logic described above, you can add business logic in Java, JS or Codeless to handle the following events:
clientConnected:
In this event handler you would mark your user as online
clientDisconnected:
In here your cloud code would mark the user as offline:
The code to change the state of the user is trivial - it is a simple update of a single property.
Hope this helps.
Mark
hi everyone! New Backendless user here so apologies if this is a basic question. I am guessing clientDisconnected fires if:
- internet connection drops out
- app is closed
- user logs out
but not on less drastic events, like:
- user minimizes our window
- user maximizes another window
- user powers off their phone screen
- etc
But in a modern app, such as chat, these events would also usually be counted as the user no longer being “online”. So is there a way to measure “online” precisely in this way, as our app is visible to the user?
Hello @JohnP
I guess, if the system do not close a connection with the server in these cases there is should be a reason for that.
So, in my vision, the behaviour you are looking for should be implemented on the client-side, an OS should have an API to determine the following actions:
- user minimizes our window
- user maximizes another window
- user powers off their phone screen
- etc
and once one of them is fired you can disconnect/connect your client from/to the server.
Does it make sense?
Regards, Vlad
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Yes! thats right. So maybe I could rephrase my question as: is Backendless UI Builder able to listen for such actions?
To say a concrete example, the Page Visibility API is one such useful API that web browsers implement to notify about events such as
- user minimizes our window
- user maximizes another window
In code, to listen to this API I would write:
window.addEventListener('visibilitychange', visibilityChangeHandler)
Is it possible to do this with Backendless UI Builder?
you can use Custom Code codeless block to run any JS code
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thanks @vladimir-upirov! Putting
window.addEventListener('visibilitychange', () => console.log('visibility changed')
inside a Custom Code codeless block works successfully. But is there any way to let this event listener communicate back with the UI?
Or, alternatively, would I need to use code inside the listener to communicate with the Backendless backend, such as:
const Backendless = await BackendlessUI.requireModule('backendless')
Backendless.initApp(APP_ID, JS_API_KEY)
const updateUserOnline = online => () => Backendless.Data.of('Person').save({ userId, online })
window.addEventListener('visibilitychange', updateUserOnline(!document.hidden))
Hi John,
When you ask if it is possible to communicate back with the UI, do you need to send the value of updateUserOnline back into Codeless?
Regards,
Mark
Yes, exactly! I need to send the value of document.hidden back into Codeless.
ah no, sorry, I only want to send document.hidden back when the eventListener detects it has changed.
I don’t think I can do it directly like below, right, as document.hidden just gets returned into the ether of the process that called it back? -
So, would it instead be correct to use BackendlessUI.requireModule to load the Backendless node module to send the changed value back to the database? -
…or is there a more elegant way to communicate the changed value directly back to the UI?