Considering network traffic in iPhone apps for users's benefit - ios

In the iPhone apps, network traffic via cellular network usually will cost users money by sending network request etc, so we need try to avoid such architecture or technical solutions for the apps to avoid cost much money for users.
Does that make sense ? And also try to look for any policy from Apple about this, any clues ?
As I know Apple push notification should be better than such polling approach which need send request to server periodically.
What are the alternative solutions in such cases ?

You could test to see if the user if on Wifi or the cellular network (use Reachability for this). If they are on the cellular network warn them that you are going to be using a lot of data.
It's also important to only load data when necessary. Don't download all your data when the app loads. Do it when the view appears (and do it in a background thread to prevent the UI locking).
You should optimise any data you will be downloading. e.g. if you are going to download a load of images or audio files download a compressed (zip) file containing them and then unzip it on the device.

Related

how to disable wifi assist without user interaction

I have couple of URLs that has to be called(programatically) through wifi not with mobile data.
As WIFI ASSIST is on , whenever the wifi is weak ,packets get transferred through Mobile data.
I would like to stop this from happening.
As far as I have researched, there is no API to toggle wifi assist switch on and off programatically
I can find if the user has mobile data and wifi on with the help of Reachability Class I believe and I can alert the user to keep wifi assist off but this is a very bad user experience.
so I decided to look if its possible to be done with the help of iOS mobile configuration file.
But I couldn't find any keys related with wifi-assist in Apple configuration profile reference.
so I am wondering , is it possible to force wifi to be used for certain URLs.
I remember this is possible with VPN ON DEMAND we can have certain domains to be accessed via VPN.
I am wondering if same is possible for wifi as well through configuration profile
Any suggestions are welcome.
As others have mentioned, there is no way to do manipulate this setting programmatically in iOS. This is not really what you are asking, as you seem to already know the answer to this is "No".
You are asking about the configuration profile, so I am assuming these are managed devices. Unfortunately, there is no configuration profile payload I am aware of that forces the managed devices to disable Wi-Fi Assist.
Your intent, however, is a bit different than what is being asked, I believe. I think you basically have an app that communicates with a resource that is only accessible via the Wi-Fi network (likely a corporate Wi-Fi network). If the app tries to connect to the resource while on cellular, it will not be able to connect. In some cases, when the Wi-Fi signal is weak, the device tries to be helpful and switches to cellular, causing issues with the app. If we could figure out a way to force iOS to not take advantage of Wi-Fi Assist when your app is running, you would be in good shape.
If you can install this app as a managed app, there is a way to identify that the app should only be allowed to run on a Wi-Fi connection. Setting the network usage rules AllowCellularData to false should do this (see this for more details). The thing I am not sure of with this solution, is whether this simply causes the connections to fail when Wi-Fi Assist is on and active, or if it makes iOS prefer to not use Wi-Fi assist when the app is running because it cannot connect over cellular. So I think you can tell an app to only connect over WiFi, but it doesn't really give you a better solution to your user experience problem. The only think it really buys you is that your app connection won't ever try to connect when connected to cellular. There is a chance, however, if you change this value to false for your app bundle ID, it will prevent Wi-Fi Assist from enabling when your app is running. I don't have access to MDM to try it out, but you could test and see.
Ultimately, given that this is probably a corporate device situation, I think you are going to have to address this through user training. The good news is that this is a one-time step. Sure, users may have slight degradation of network performance when Wi-Fi signal is weak but cell signal is strong. This does not matter as much if these are corporate devices where the corporate apps will mostly work only on the company's Wi-Fi network.
Another solution is what you mentioned, basically using on-demand VPN to provide a connection to the internal resources. This is additional infrastructure work, and you already mentioned it, so I'm not sure if it is even an option.
Obviously, the other solution would be to expose the network resources through your firewall, which could allow you to access it over cellular. I'm suspecting this is not possible due to security constraints.
Unfortunately, there are not a lot of good options in this space. However, have hope that there is some way to do it, as Sonos appears to have done something to
allow their app to avoid switching to WiFi Assist while streaming to a local network resource: https://sonos.custhelp.com/app/answers/detail/a_id/4257/~/wi-fi-assist-and-sonos
I wonder if you could have your app open a streaming audio connection to a fixed local network resource, which would cause it to use Wi-Fi. It's a pretty crazy hack, but with a low enough bitrate audio file streaming, it might do what you need while not eating up too much of the network throughput.
Per Apple's notes on Wi-Fi Assist:
Wi-Fi Assist won't automatically switch to cellular if you're data
roaming.
Wi-Fi Assist only works when you have apps running in the
foreground and doesn't activate with background downloading of
content.
Wi-Fi Assist doesn’t activate with some third-party apps
that stream audio or video, or download attachments, like an email
app, as they might use large amounts of data.
Of course the other possible solution that you could consider is improving your Wi-Fi coverage to that the signal doesn't get bad enough for Wi-Fi Assist to be needed. I know this may not be feasible, but wanted to put it out there.
Good luck with this!
There is no public API that allows you to enable/disable "Wi-Fi Assist", and even if you find a way to do it your app will be rejected.
No you can not enable or disable WiFi by programmatically and there is no API for this.

is it possible to get signal strength and channels of a wifi?

for Android, several apps exist that show such information, like https://play.google.com/store/apps/details?id=com.farproc.wifi.analyzer does it:
I need similar functionality in my iOS app but can't find any information about that. It this forbidden by Apple?
Apple doesn't allow apps to access the hardware like that. A fairly common workaround is to measure network throughput instead. You could take periodic samples of the current network speed, and then display that data over time.
Network Multimeter, for example, is an app that will give you info on your network as you walk around. It does that by sending data across the network and displaying the throughput.

For my task how should you communicate between iphone devices over the 3G network?

I have a situation where I would like to communicate between 2-4 devices over the 3G network (it should also work over WLAN, but 3G solution is critical).
Every device (except one) asks for a GPS-location every ~5 seconds, but when this process is cancelled by the user of that device, one device needs to be informed of this event.
I was thinking that one device could act as a server, and the rest as clients that should connect to the server. Is this possible over the 3G network?
I've also read about push-notifications, is this relevant here? Can you receive notifications without disturbing the user with a popups etc?
Are there other ways?
Basically I would like to use apple "standard" solutions (if there are any) before diving into eventual socket-programming or anything similar...
What I would like to avoid is to have a webserver or some similar "3rd-party" solution, because I don't want many users to simultaniously connect and "pull" from the same external server in a final solution...
UPDATE:
Basically my application will have thousands of users that will need to be informed if an even occurs. Also this happens simultanously ~5 second, what would be the best solution to reduce load and avoid spamming?
I was thinking that one device could act as a server, and the rest as
clients that should connect to the server. Is this possible over the
3G network?
It could work, but having a dedicated server would be a better choice
I've also read about push-notifications, is this relevant here? Can
you receive notifications without disturbing the user with a popups
etc?
In your case no, since you will need a server to communicate with apple
Basically I would like to use apple "standard" solutions (if there are
any) before diving into eventual socket-programming or anything
similar...
There are no standard solution, other than you should probably rethink about using a dedicated remote server for this
iPhones can't communicate directly with each other using 3G. You can access the internet through the 3G, but you can't do peer-to-peer as you are suggesting. If you were close enough, you could use bluetooth, but I expect you are too far away.
You would have no way of detecting the one device that acts as a server from the other devices. The IP address could (and probably would) change every time the device connects to a mobile data network. You would need a central server to co-ordinate all of the clients.
You have multiple questions, but I'll try to address as many of them as I can:
I was thinking that one device could act as a server, and the rest as
clients that should connect to the server. Is this possible over the
3G network?
No, you cannot run a server on a iPhone/iPad that is accessible over 3G without an external website acting as an intermediary. (You can run one that is accessible over Wi-Fi, but this does not solve your problem as stated.)
I've also read about push-notifications, is this relevant here? Can
you receive notifications without disturbing the user with a popups
etc?
Push requires you (or a third party contracted by you) to have a web server, so if you want a server-free solution it is not relevant here.
Are there other ways?
Over 3G you will, under the current Apple restrictions, always need an external server.
Basically I would like to use apple "standard" solutions (if there are any) before diving into eventual socket-programming or anything similar...
Diving won't help you here. Even using low-level socket programming you will not be able to run a server on an iPhone accessible over 3G without an external website to aid in establishing a connection.
You can try using GameCenter. The mechanism of network games in Game Center allows connect up to four players with no third-party solutions.

Long time downloading in iOS app

How many issues need to be considered carefully if a large of content need to be downloaded in an iOS app ?
Here are my known issues:
Network , No limits for Wifi, but Apple has limit policy for cellular network. enter link description here
Background execution. Apple introduced multitasking for several cases, but no for downloading large content background. Here is a good analysis.
Newsstand provides good solution for this. But does that mean you need follow the Newsstand approach ? We do not want to build an newsstand type app.
What else issues do you think ? and what is the best solution for this sort of problem ?
I would lazy load only data as needed. When the user requests an area load revenant data.
If you want to preload do it in the background. I have seen 1.6Gb apps with lots of videos, embedded in main bundle, but that was for sales app that needed to have all videos ready to go and could not assume any active network connection.
Download the data you need in a background thread while your app is running. If your app is terminated or suspended before you get all the data, resume where you left off the next time the app is running. There are a number of ways that you can do that; one good one is to break your data up into smaller chunks that can be downloaded sequentially.

iOS app with real-time updates from server: Socket (using streams) or Apple Push Notification service?

I'm trying to make an iOS 5 app that features real-time things coming from the server. It will only use these whilst the app is running.
To make it real-time without polling I have been evaluating two design routes:
Creating a socket from the app to the server, and exchanging information via streams.
Pros: Relatively simple and would not involve a 3rd party.
Cons: Battery life drain.
For an overview of how this might work, check
out this excellent tutorial:
http://www.raywenderlich.com/3932/how-to-create-a-socket-based-iphone-app-and-server
Using standard HTTP to communicate with the server, and with each request from the app let the server know what they are viewing. If something new is available for user, send an Apple Push Notification (with no visible alert) to let app know it can go and download new thing.
Pros: Not opening up a new TCP connection, so battery life not drained unnecessarily.
Cons: Feels like a poor hack.
The official docs on APNs http://developer.apple.com/library/mac/#documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/ApplePushService/ApplePushService.html
I think a socket would be the way to go, but before I commit to it I wanted a second opinion, as this is the first time I've made anything like this!
Sockets would be my choice. I do not know how time critical your application is, but sockets might perform better as APNs if realtime is a must.
Does it really need to be "full real time"? From my point of view i would prefer http since it is already well integrated into the iOS SDK. Its easy to understand, maintain and implement and plenty of documentation is on the web. So maybe a http poll every minute or so will be enough (depending on the app and the number of users). Please consider firewalls too! Traffic to unknown ports maybe denied due to firewall policies of provider or local wifi. So if you really need realtime connectivity I guess you have to use sockets.

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