I wish to be able to prompt the user with contextual local notification depending of his current wifi network.
To do so I would need to monitor network change/ wifi connection.
Doing that while the app is running does not seems difficult, but I'm trying to think of a way that could always be reliable, even if app is in background or killed.
I was thinking of using a NetworkExtension, and more precisely a NEHotspotHelper.
Has anyone any insight on this to know if it's doable/good/bad? I can't find anything about it on google.
The most promising thing is NWPathMonitor, but is using that in a network extension the way to have it always running?
It's definitely possible, NWPathMonitor is the right way to monitor the network (see my POC: https://github.com/federicocappelli/NetworkPathMonitor) and it's battle-tested in a network extension (NSDNSProxyprovider in my case).
From the network extension you can easily send local notifications.
Related
What actual method calls, excluding Bonjour, triggers the "would like to find and connect to devices on your local network" permission notification on iOS 14?
This is the screen shot from the WWDC session on this new permission. Which is only somewhat helpful as an overview. I'm more interested in figuring out what all method calls trigger this.
If you're using react native with a debug configuration, then you are including all the code responsible for communicating with your dev machine so you can probably ignore this message.
However it's best to check you have no other libs that require access too. To do this just build a Release version and see if the message persists.
In a nutshell, Bonjour. Its use is no longer "transparent". See https://developer.apple.com/videos/play/wwdc2020/10110/ for more information:
If your app interacts with devices using Bonjour or other local networking protocols, you must add support for local network privacy permissions in iOS 14.
Even an existing app is subject to this rule; the first attempt to use Bonjour triggers the authorization alert.
Apple (Eskimo on the Dev Forums) released a FAQ providing more details around this alert:
https://developer.apple.com/forums/thread/663858
Particularly, providing more info as to what triggers this alert is FAQ-2:
https://developer.apple.com/forums/thread/663874
What operations require local network access?
The general rule is that outgoing traffic to a local network address
requires that the user grant your app local network access. Common
scenarios include:
Making an outgoing TCP connection — yes
Listening for and accepting incoming TCP connections — no
Sending a UDP unicast — yes
Sending a UDP multicast — yes
Sending a UDP broadcast — yes
Receiving an incoming UDP unicast — no
Receiving an incoming UDP multicast — yes
Receiving an incoming UDP broadcast — yes
These TCP and UDP checks are done at the lowest levels of the system
and thus apply to all networking APIs. This includes Network
framework, BSD Sockets, NSStream, NSURLSession and WKWebView, and any
other protocols that you layer on top of those.
IMPORTANT Receiving an incoming UDP multicast or broadcast does not
currently require local network access but, because we hope to change
that in a future update, our advice right now is that you write your
code as if did (r. 69792887, 70017649).
Resolving link-local DNS names (those ending with local, per RFC 6762)
requires local network access. Again, this check applies to a wide
variety of APIs including <dns_sd.h>, <net_db.h>, Network framework,
NSStream, and NSURLSession.
Finally, all Bonjour operations require local network access:
Registering a service with Bonjour — yes
Browsing for Bonjour services — yes
Resolving a Bonjour service — yes
Again, these checks apply to all APIs that use Bonjour, including
<dns_sd.h>, Network framework, NSNetService, and Multipeer
Connectivity.
Note You must declare the Bonjour service types you use in your
Info.plist. See How do I map my Multipeer Connectivity service type to
an entry in the Bonjour services property? for details.
Bonjour-based services where you don’t see any details of the network
do not require local network access. These include:
AirPlay — no
Printing via UIKit — no
One of my apps was triggering this prompt unexpectedly in our internet multiplayer mode. We use RakNet for our networking (which is a C++ lib that uses BSD sockets to send/receive UDP) and I was able to track the problem to the RNS2_Berkley::BindShared function here.
After creating a UDP socket, RakNet tests health/validity of the socket by having it send a little test packet to itself. iOS 14 was flagging this send-to-self behaviour as communication on the local network. I'm not sure if this send-to-self behaviour is a common pattern in socket programming, or a particular quirk of RakNet. Frustratingly, the OS prompt didn't actually appear until later when the socket was used for real which made the issue very hard to track.
I think that this is a false-positive from the OS and raised it with Apple (FB8802121). I won't be holding my breath though so I've just disabled that RakNet behaviour for iOS and am hoping that it wasn't too important.
Edit: To more directly answer the original question: sendto is a method call that can trigger this prompt.
I get rejected from apple app review for this alert. I'm using GCDWebServer which creates an embedded http server in my app.
I think I should provide a message in info.plist to tell user what my app want to do. Before I didn't set the text string in it.
And I would like to update if this will pass the app review.
<key>NSLocalNetworkUsageDescription</key>
<string>xxx uses the local network to connect with devices around you.</string>
Regarding iOS 14: permission request: would like to find and connect to devices on your local network and after numerous deploys to my physical device, I have figured out what causes this in my case.
I have a Xamarin.Forms app which
calls localhost:xxxx to do some local logging while I develop
I use a product thats called LiveSharp that does local hot reloading for XAML AND C# code changes.
So Livesharp actually communicates with a server on my localhost as well.
After disabling both of these and a fresh clean install on my physical device, the permission request has GONE .. Yay
Note: I had to completely remove LiveSharp nuget packages from my project.
Also I tried to re-enable my localhost logging, and for some reason the permission request does not appear.. :headscratch
So: remove any localhost communication that happens in your app. Or at least put an if statement around it allowing it if set to true in appsettings
I also have a Xamarin app and I used the package LiveXaml. After removing it the message was gone.
I have an issue in my app where if a client is running my app but does not have wifi enabled, the app does not find my service and returns an "Unknown error" CFNetServiceError code 72000. The client enables wifi, connects, and my app is clueless.
The obvious fix is to add a notification for when a local wifi network is connected and reinitiate the NSNetServiceBrowser's search.
I don't know how to do that in C, so I was hoping to use Reachability. To my dismay, the solution I seek has recently been removed.
This is from the Reachability ReadMe file.
Removal of reachabilityForLocalWiFi
Older versions of this sample included the method reachabilityForLocalWiFi. As originally designed, this method allowed
apps using Bonjour to check the status of "local only" Wi-Fi (Wi-Fi
without a connection to the larger internet) to determine whether or
not they should advertise or browse. However, the additional
peer-to-peer APIs that have since been added to iOS and OS X have
rendered it largely obsolete. Because of the narrow use case for this
API and the large potential for misuse, reachabilityForLocalWiFi has
been removed from Reachability.
Ok, fine. But what the hell are these additional APIs? I need a method. :(
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
I am working on a web application for iOS that is going to be accesed from a local webserver in a network that has NO internet connectivity at all.
My problem is that everytime an iOS device is locked, it disconnects from the WiFi network, so when the device is unlocked again, it has to reconnect. Part of that reconnection process is determining if there is Internet connection (which there isn't). Until the process is not finished iOS does not allow any DNS resolution (so if I write http://10.0.0.1 it will go there, but not if I request http://something.local.com).
Since we control that network, we want to know how to does iOS verifies Internet connectivity so that we can fake the responses it expects.
I don't know if it's possible to resolve DNS without an internet connection on iOS, but if that's the case, that would be a way better solution since you don't need to mess with your router settings. Use my solution only if it really isn't possible with only code.
I'll suggest you to follow this guide: http://blog.jerodsanto.net/2009/06/sniff-your-iphones-network-traffic to check which actions your iPhone executes to detect an internet connection.
Using this information you could forward the is-there-internet-requests on your router to a local server which fakes the there-is-internet-responses.
This assumes Apple really uses an external server to detect this, which I'm not sure about. But it wouldn't hurt to give it a try!
Have you looked at the Reachability Class? You don't have to use the reachabilityForInternetConnection method, which checks if a default route is available. You can use the reachabilityWithAddress: method and check if your server is reachable.
First of all, I know I can use UIRequiresPersistentWiFi to specify that my app needs WiFi.
But in fact, my app works fine with both WiFi or 3G. How can I express such a network requirement? It there any Info.plist key for this? Or is testing myself with Reachability the only way to go?
What exactly are you trying to do? If all you need is network access, then you don't have to do anything at all to make it work. Reachability can be useful, because it lets you quickly test if the network is available before attempting to connect anywhere, but that's only useful if you need to know if there is a network before even attempting to use it. Under normal circumstances, you can just attempt to use the network, and gracefully handle any errors that may occur.
My suggestion would be use SCNetworkReachabilitySetCallback (which gets called whenever the status of the network changes) and then throw an error if there's no WiFi or 3G connection.
b.t.w., all the keys UIKit supports in Info.plist can be seen at http://developer.apple.com/library/ios/#documentation/general/Reference/InfoPlistKeyReference/Articles/iPhoneOSKeys.html