I have an idea for an app that utilises Live Activities, inspired by the Flightly app (it starts a Live Activity for a plane ride): Basically I wanna use open data from an HTTP endpoint that is reachable via the onboard WiFi on a bus. E.g. you board the bus, connect to the onboard WiFi, open the app, it fetches details about the stops and then you start a Live Activity guiding you to a selected stop. So far so good. But sometimes the bus faces delays, etc. In that case, I need to update the Live Activity. That is easy when my app is running. It is not so easy, when my app is not running (or running in the background).
What is my best approach to regularly fetching data from the endpoint and updating my Live Activity? The problem is, that the endpoint is only reachable on the buses WiFi. So it looks like I cannot use APNS to push updates to the Live Activity (since my service running outside the bus cannot access the endpoint that provides the details and thus cannot push any meaningful updates). Background Tasks (e.g. background app refresh) run infrequently.
What options are left? I thought about receiving location updates in the background and acting on them to update my app state (and possible the Live Activity, if needed), although I haven't investigated that path in detail, yet.
Has anybody faced a similar issue and found a solution or can provide some guidance on how to approach this problem?
I think the easiest option is core location. So keep your application running by monitoring the position and then you can update the Live Activity by fetching the information from your access point. It should be fine for app review since you could use the the location to show a position on a map and only while the person is on the bus.
If your application isn't running you have to send the ActivityAttributes via APNS. Since the data cannot be accessed from a remote server that would communicate with APNS there is no direct way to use ActivityKit push notifications. An indirect approach (which I would not recommend) would be to send silent push notifications triggers every 5min or so and fetch the newest information when the application is woken up. But this won't work when the app is force-quit and using silent pushes to trigger polling will give you a bad score by the system and eventually the frequency will be throttled from APNS.
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We are building an iOS iPhone app that needs to check-in with a server on a 12 hour basis. This is needed to let the server know that the app is still using it's service on the server. To our understanding this is possible when the app is in background state (not showing on the foreground) via backgound fetch or remote notifications.
But this is not possbile when the app is not running or terminated, when the app is in these states then there is no way to initiate communication with a server. Is this statement corret? Is it possible initiate the communication after a device bootup, is it then possible to send a small keep alive message to te sever?
The background fetch and responding to remote notifcations is not possible in the not running and termenating states(?), so we cannot use these mecahnisms for this purpose. If that is the case are there any other solutions that we can try? Or is it just not possible?
We looked at many sources on the internet but some say that it is possible and others say it is not.
You might want to take a look at the Silent Push Notifications. Here is the thing, if the app is in background mode or suspended state, you will be fine. If the app was killed by the user, you have a problem.
You can always send a silent push notification, and wait for a service call made from the device to your service. If there is a response, it means the app was in background or suspended, and then you can go ahead and do whatever you need to do. If no request is made, it means that app was killed. Then you might want a sent a non silent push letting the user of that device know that he needs to launch the app or something like that. I don't know how you are going to work around it, but that could be a possibility.
I would tell you to take a look at NSURLSession and Background NSURLSessionConfiguration as well, but you will run into the same issue. If the user manually terminates the app, you need to find a work around to set up that connection to the server, and that will imply the user to somehow launch your application.
I would like to implement a geofence based domotic activation system.
There are different ways to define a geofence (e.g.). What I am concerned about is how this will all come together (service activation).
I am thinking of the use case where the geofence is set up by the user via phone (say via the App I am developing). Once this is done then the data will be stored in a remote webservice. iOS app development guidelines says that you cannot have an app running in the background and here my doubts start..
The point of defining the geofence is to activate some domestic/domotic service once the user enters the geofence that he defined as house. However if the App is running on background how can I get the app to communicate the position to the web service?
I have found this tutorial on remote background data fetching.
Apple developer documentation mentions that you can get background location change updates and hence I assume I can have some code to perform certain actions within the app when I receive a location change call back (from the location manager service). If this is correct I am then wondering whether combining this step plus using remote posting of data may be a valid solution (this has to happen when the app is in background mode).
If not would you be able to suggest an alternative approach?
I believe that if you request notifications within a geo fence you app will be woken up to get the notification, you can use this notification to then request a background session, which can then be used to update your web service.
For a project I need many clients to subscribe to different hardware devices. In this setup the clients are iOS - Devices. The hardware is something like a raspberry pi but i don't think this matters. This hardware devices send a signal if it measures some kind of information. This is a rare event and possibly could never happen.
Purpose of the app is to warn the user when some kind of event appears in a location he is interested to.
I planed to implement this using the MQTT protocol.
That is where my problem is. To work with MQTT the app needs to send PINGREQ every few minutes even when the app is in background. Also the app needs to receive its subscriptions and handle them immediately.
This is what I planned to do:
Set the "UIBackgroundModes" key in Info.plist to "voip".
Mark the socket as voip socket to wake the app when it receives something
Set the keepAliveTimer:callback: and send the PINGREQ
.. as described here
My questions are: Will Apple allow this? My app is not an VoIP app. If no, are there any alternatives to this approach?
If Apple policies doesn't allow your to put your MQTT client App running in the background, then the solution should be to implement an additional push service.
A push service subscribes to your MQTT broker and sends push notifications to your mobile devices, so that either they have the MQTT client App running or not they will get the events.
Yes!
There is a chance that apple can reject your application when you are using VOIP(even though your app is not a VOIP Kind of application) to keep application alive!
I'm using Location services which is a proper solution to keep application alive in background mode.
Ask permissions to use location services even when the app in background mode & after getting the allow call back,set your location manager's desired accuracy to worst,distance filter to 99999(means your app will be notified if the user travels more than 99999 Meters from last location update call back)
By altering the desired Accuracy and distance filters you can save the user's battery consumption,otherwise your app will consumes lot of energy
That was one proper way which makes your application to run in background for more than 2 days continuously (Already using in our projects).
HTH! Have fun in coding :)
I have a chat application developed by JS. I want to send PING to server once in a while. Its not a problem if app runs on fore ground. The problem is when user minimizes it or open another app. My app looses its focus and gets into suspended state.
I have following two use-cases.
To keep the chat session open I need to send PING to server (Its an IRC server) every X minutes even the app runs in background.
We also need to check for new messages (by ajax on a local http server) and add a local notification to the notification queue so when user clicks on it app can resume
I have found apple does not allow running apps in the background. if they allow they require special permission. I found some apps does it by requesting finite length execution time.
What is the best way to get highest possible background execution time? As a chat app can I request permission for voip, location or any other way ?
Note: the app will be running in an environment where there is no Internet. Hence push notification will not work here.
Update: After doing a lot searching I found background fetch. It seem background fetch will suite it. But still the problem remains, its not called in a timely manner.
This sounds like an interesting problem. From reading the various comments, it sounds like you want this to work when you're on a local network - so you have wifi, but the wifi router/base station isn't connected to the actual internet?
Because background refresh isn't going to be predictable - you'll never know when it is going to update - you might want to get creative.
You could look into exploiting iOS VOIP support, only without the Voice! Apple has some tips on VOIP here. VOIP basically uses something called SIP (Session Initiation Protocol), which is signalling layer of the call, and a lot like HTTP. It's this SIP layer that you want to take advantage of.
This isn't going to be terribly easy, but it should be achievable. Setup your app to use VOIP, and then look into something like PJSip as your SIP library. Then, on your local network have a SIP Server (I'm sure there are plenty open source implementations) that you can register your iPhone against (so your server knows where your phone is, pretending to be a VOIP phone). This should work, because it doesn't need to go through Apple as far as I am aware... And will run happily on your local network.
Then, the server can send a message via SIP to the handset, as if it were instigating a VOIP session. You app is awoken, gets the messages - ideally from the SIP message if possible - and then just doesn't start the session. SIP was designed just for creating sessions, not just VOIP. When I worked in Telecoms R&D (a long time ago) we were using it to swap between Text/Voice/Video, all using local servers.
You'll have to jump a lot of hoops to make this work, but it would be pretty awesome. I have never tried this actual use case - especially with iOS, but I'm fairly sure it will work. It is a bit of a fudge, but should get you where you need to go.
Good luck!
You can use something like PubNub to build this chat app with iOS using native Objective-C code, or with the Phonegap (Cordova) libs.
The beauty with using a real-time messaging network like PubNub is that when the app goes to the background, you can easily have the chat messages come in on APNS.
When the app is in the foreground, it can just receive them as the native (PubNub) message. And if it needs to "catch-up" with the messages it missed while in the background (but received via APNS), its trivial to implement.
Also, PubNub is platform agnostic -- so you can easily also use it on Web, Android, BB, Windows Phone, etc.
http://www.pubnub.com/blog/build-real-time-chat-10-lines-code/
http://www.pubnub.com/blog/html5-websockets-beautiful-real-time-chat-on-mobile-using-pubnubs-channel-presence/
https://github.com/pubnub/objective-c/tree/master/iOS
https://github.com/pubnub/javascript/tree/master/phonegap
geremy
Is it possible to interface with a webservice (or, for what matter, do any scheduled local or remote activity) while the app is in background?
I know that you can receive remote pushes or schedule local alerts, but I wonder if I can periodically send my GPS position to a webservice even if the app is not in foreground.
I have been thinking about this myself in an attempt to impress my boss with an iPhone/iPad App that accesses our Web Service.
If the Web Service takes a non-trivial amount of time to process a request then there is absolutely no guarantee that the App won't be interrupted and stopped, therefore making it useless for any business-level tool. The only Apps that are allowed to run for extended periods in the background are a select set that use certain frameworks (music players, etc.).
I concluded that the only way of doing it is to introduce a middle tier that performs and waits for the response from the actual Web Service and provides an interface that the iOS App can poll or be pushed to in order to allow it to sleep/die whenever iOS thinks it should.
You can make sporadic network calls while you are running in the background if you are a location-based app with proper permissions. You need to make sure you are running a background task properly. FYI, there are a number of applications in the app store that do this.