Iphone - Notify from the server to the client when an event occurs - ios

im stuck in a situation
SITUATION : I have a situation wherein i answer some questions and get points according to the answered questions. if my points become say 10 i win some gift using a QRCode. (there is a qr code that is generated to the user, and when the qrcode is scanned from someother device which has a scanner app or any other scanner, it gives a link to that online store. This link can be opened from any browser.) The gift is accessed from some online store by scanning the QRCode which gives a link to that online store with some unique id and when the gift is accessed/taken the server is notified that the gift is accessed/taken from that online gift store and the QRCode status is updated to invalid on the server database. Now once the server gets the notification that the gift is being accessed/taken, the server should immediately notify my iphone app that the gift is received so that i can immediately show another congratulations image or something.
POSSIBLE SOLUTION : i thought of one possible solution wherein i check upon the qrcode access status change on the server every say 60 secs and display the image accordingly. I dont know how efficient/correct this way would be though.
ISSUE : but before i refuge to the above solution, i want to know, can this notification happen from the server without my app trying to call or fetch the update from the server? I mean, my app comes into the picture only after the server sends a notification in the form of a msg or some xml or something..
Any help would be deeply appreciated.

You can open a connection to your server using CFReadStream, add the stream to your runloop and set up a callback function. Whenever the server writes data to the open connection, your callback will fire and you can then read from the stream to get the data the server sent
More info here: https://developer.apple.com/library/mac/#documentation/Networking/Conceptual/CFNetwork/CFStreamTasks/CFStreamTasks.html

You could try to check Push Notifications. But it's impossible to determine on server side if notification was received on client side or not (if you won't implement it by yourself, but you'll probably wont cover all the possible situations, like when your app is not launched and notification came).

you can try to use XMPP protocol, which is most commonly used for chats/mails, where the changes in the server is notified to the clients.

Apple Push Notification Service is meant to solve these types of situations.
Hope it helps:
Apple Docs: http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/ApplePushService/ApplePushService.html#//apple_ref/doc/uid/TP40008194-CH100-SW9
There is a nice tutorial: http://www.raywenderlich.com/3443/apple-push-notification-services-tutorial-part-12
Video tutorial: http://www.youtube.com/watch?v=cKV5csbueHA&feature=relmfu

Related

How to get updates from the server promptly?

I have an iOS app which displays some information fetched from the server.
The app communicates with the server using REST API, and makes GET requests periodically (or when user pulls-to-refresh). However, we need better synchronization. As soon as data changed on server, we want to reflect it in the mobile app.
How can I get notifications from the server when data changed and update needed? I thought about silent push notifications, but they do not look a right choice here.
Are there alternatives? May socket programming help? I have no an experience in it, but I it is relevant, I will start digging.

How to update app when new data is available

I'm fairly new to app development and am having trouble figuring this out. One part of my app involves a messaging platform. Right now I am using a php web server to connect to MySQL backend. I have all the functionality of a messaging app, but I am unsure how to push new messages when they are available.
One basic solution would be to call my function to check for new messages every x amount of seconds, but obviously that's not a good solution. I have looked into Apple Push Notification Service and am unsure if this would fit my needs. When I looked into it this seems to be for sending notifications to the user remotely. However, rather than the user getting these messages displayed I would like the app to call a function instead (the function would load the new messages). Is this possible with push notifications?
Also this app is on both iOS and Android, so if there is a (possibly third party) solution that would cover both it would be ideal.
Any insight into this problem is greatly appreciated!
When you send a push notification and the app is in the foreground, the AppDelegate has a method called which allows you to execute whatever method you want.
This is only for iOS though, I don't know know it's handled in Android.

AFNetworking and Push Notifications

I am working on an application which GET and POST information to a server. I am doing so using AFNetworking framework. My aim is to push a notification to a client whenever someone posts new info to the server. Eg: a new grade is published, the student who's grade was published must receive a notification on his iDevice.
Although I am not familiar with how Apple Push Notification works, from what I read I concluded that I need to add server side code in order to trigger a notification.
Note that I don't have access to the server. Service is provided by Fedena.
Any suggestions or hints from where to start?
APNS needs a server in order to work. The usual flow goes like this:
The iOS Application asks user to enable push notifications
Upon access granted, a device token is generated and then must be sent to the server.
Your server must be setup with the proper APNS certificates generated from the Apple Developer site
Then in your server's, when a new post is created, you need to add some logic where you load all the APNS token you've received already and then send the notification to the devices.
This is a very simple flow description but I guess you understood that you need to have access to the server to be able to do what you are trying to achieve.
Some third parties exists to handle push notifications (like Urban Airship), but those push notifications are usually pushed manually from a person, and not triggered from a server event
I recommend that you can use secondary server of your own as intermediate and use it as infrastructure back bone.You can use SignalR library. Use secondary server as to create connection between two devises. One client will push events and another client will listen to events.
Here is the link to the signalR library code written in IOS.
I am currently using these library. What you can do is start hub and connection using these library.
This library allows invoking method on server. Something like this.
[_hub invoke:#"MehtodName" withArgs:params];
What i would do is to create event registry on server. So one client can listen to event on server and other can push events or vice versa.
So your student device can invoke method "subscribe to events" and server will add it into the registry list. You can create secondary service "Publish Events". Grade publisher can publish via calling this method. Here publish events will look up registry and find interested clients and call desired method on client.
Read more about signalr through this site.
Benefit of using Signalr Over APNS.
Cost Effective. As this will save you money which you might have to pay to Apple for pushing notification.
Can Easily make it cross plateform in future. Just have to impletement similar library in Android/Windows.
Quicker as the data does not travel to apple server from your server.
Worst case you can fallback to apns any day, just put push notification code in any of your secondary server methods.
I have done battery and performance testing as well and works perfectly fine.
If you wanna know, here how it handles connection which is very reliable.
SRAutoTransport chooses the best supported transport for both client
and server. This achieved by falling back to less performant
transports. The default transport fallback is:
SRWebSocketTransport
SRServerSentEventsTransport
SRLongPollingTransport
Let me know if you have anyother question. i am currently doing similar work, might be able to help you with your issue.

iOS - Push notifications and background threading

I have a service that allows user to enter the type of events they like, and whenever a new event that fits those criteria is available in my database, I want them to get a notification.
I have been looking around at the best way to handle it and I have found two possible solutions, but I'm not very clear with which one I should use and how.
First, a solution that looked great was the didReceiveRemoteNotification method and the usage of remote silent notifications to tell the app that new content was available. But my questions remains: how can I send this remote notification to the user if I don't know which criteria he has. I mean, how can I send this notification using PHP? I'm a bit lost here.
So I found another possible solution that does look a lot like a hack (iPhone - Backgrounding to poll for events), to be able to make your app execute a method every XX minutes while it is in background. This would be way more battery consuming and I'm not even sure it would be accepted by Apple, but at least it is clear as to how it works: the app downloads data from a link with the parameters that fit the special criteria, and if there is new data, it sends a notification.
How could I combine both these methods?
EDIT
I think the main issue on my side is that I don't understand how I could check a certain PHP file whenever new data is added into mysql and make sure that it fits the criteria of the user and then send the notification. That is the part that I don't understand in the backend PHP usage.
Your flow should be like this -
Mobile -> BackendServer(PHP) -> APNS server -> Notifications->Back on device.
User will submit her/his criteria to server then server will process on that and send request to APNS server.
The APNS server will send remote notification on her/his device based on criteria requested.

iPhone app development. How does an app like snapchat send data from user to user?

I'm just starting to get into app development and have just been learning the uses of Xcode and Objective-C language. Just wondering how an app like snapchat or any other app can send data from one user to another. General answers would suffice just to better my understanding.
How do they test this functionality?
How can they connect peer to peer and send data from one phone to another? Is it all accessed in one database that the app connects to everytime that it pulls down?
When you sign up for an app like this with a registered account is that information stored on the iphone?
Well there are two ways data can be sent to a device. One is the device polls the main server periodically. This can be seen in a pull to refresh scenario. The other is the server can send a push notification to the specific phone and app which causes the data to be received by the device and displayed however the programmer wants. So device to device is essentially one person sending something through a web service call to your server. Your server them packages that information into a Json payload and sends a push notification to the recipient. It seems like its device to device because its so quick, but it requires that you have a server in the middle and of course your server is really sending the push notification to Apple's push server, so there really are two servers involved.
How do they test this functionality?
I would try to do this with real devices, and/or using a network sniffer tool to inspect the send packets.
How can they connect peer to peer and send data from one phone to another? Is it all accessed in one database that the app connects to everytime that it pulls down?
Someones sends you a snap
your app will ask the database every ...min or when you reload if there's something new to load, and gets it from the database if there is something new
When you sign up for an app like this with a registered account is that information stored on the iphone?
Connect to snapchat
get a snap from someone and wait till you can view it
start airplane mode and see if it loads, if it does there are files (temporarily) stored on your iPhone.

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