Understanding Push notifications for Windows Phone 8.1 - push-notification

I'm trying to understand what I will need to build on my server for Push notifications to work successfully.
My thoughts were:
The phone sends the notify URL to my server
The server stores the information in a Database
A separate process or PHP script will query the database and open continuous looping process for each device. (Each socket will be querying a 3rd party API)
When there is a change detected in the API for that device a push notification will be sent to the device's notify url.
Is this the right method on what needs to be done. Isn't this going to eat up server resources or is it the expected outcome of Push a push notifications server?
I've produced a simple diagram on all this below:

First of all, let's separate the process in the main stages needed for PUSH.
Device subscription.
Send the PUSH
Process the notification on device.
Subscription
For the subscription, your device (more specifically, your App) must call the PUSH api,for enabling PUSH notifications. This call to the push API will give you a URL that uniquely identify the device where your application is installed and running. You should store this URL on your database, the same way you store a user's email, or a user's phone number. No special black magic here. You only use it when you need to send a communication to a user.
Send the PUSH
For the push stuff, the same approach as for email, or SMS messaging here: "One does not simply make an infinite loop and send a message if any change is detected". What you have to do is, just send the PUSH message when your application needs to. So you have the user to which you want to send a message, instead of opening a SMTP connection to send ane mail, just build the PUSH XML Message and call the URL associated with that user. Some things to consider here are:
Network reliability (you need to retry if you can't connect to the server).
Response error code-handling (you don't need to retry if the server tells you that the phone has uninstalled your application, for example).
Scalability. You don't want to send a PUSH message from your PHP code, because you don't know how long it will take for the task to be completed. You have to make this thing asynchronously. So just queue up all the push messages, you can create a separate process (windows service, nodeJS service, cron job, daemon, etc.) to send the PUSH, handle retries and errors and clean the queue.
Process the notification on Device
So now that you are this far, you need to handle the notification on the phone. It depends on the type of PUSH notification that you are sending:
Tile. You will update the image, text and counter of the application tile, if the user has put your application to the start screen. On client side you need nothing to so, as all these parameters are part of your PUSH request.
Toast. This one requires a title, text (limited to some 35 characters more or less) and a relative URL inside of your APP. Your application will be launched (like when you click on a Toast notification from Twitter, for example) using the URI that you specify in the payload. So a bit of data can be already injected here. You may/or may not make a request to your server for new data. It is up to you.
Raw. This one is pretty much silent. Is not seen by the user if your APP is not running. As you might guess, this kind of PUSH is useful to live update your running APP, instead of continuously polling your server, wasting user battery and bandwidth and wasting your server resources. You can send anything (raw bytes or strings) up to the max size of the payload allowed my Microsoft.
If yo have any more questions, don't hesitate to ask.
Bottom line: separate the PUSH sending, make it async, don't you ever forget that...

Your PHP script that continually pings the database for changes...THAT is what will eat up your system resources. Push notifications go hand in hand with Event Driven Programming. This means that ideally, your code shouldn't continuously ping your DB. Rather, when something happens (ie, an "event"), THEN your code does something...like contact your phone via push notification.
Your steps for push notifications are more or less correct, but are incomplete. Step 4: the server contacts the client via the notify url (which you have). Step 5 is that the client then contacts the server to actually pull down the information it needs. That is: The new information is not provided to the client via the notify url. Once the client has its new information, then the program continues as normal (populates a list, downloads skynet, etc.)

Your third step is very wasteful and not practical if your app is installed on more than a few devices.
Instead, each device should be subscribed to types of server updates it cares about. Your server's DB will have a mapping from each type of update you support to the list of notification channel URLs of devices that care about this update type.
When your server detects an update of type X, it would send a notification to all devices subscribed to that type of update.

Related

Web Push. fetching web pushes sent while offline?

I am coding a vue.js app using web pushes with Firebase Cloud Messaging and I wondered if it was possible to send a web push to a user and in case the user was offline, to somehow store it for later display when the user opens the app again. Is there a principled approach to this problem, i.e. managing web pushes when the end user is offline?
The reason I am asking this is that, so far, all the web push notifications I've committed to FCM server with tokens of offline clients (i.e. desktop browsers) went into oblivion. To be sure, FCM didn't try pushing the notification again when the clients went back online.
For this reason I am considering coding a self-made dispatcher to manage web push for offline clients, but I need to make sure my efforts are worth it.
updated: I am now able to display notifications sent to an offline client after coming back online using appropriate time_to_live values. However, only the latest notification is displayed. How is there any specific reason why?
FCM's default behavior is exactly like that. From the docs:
If the device is not connected to FCM, the message is stored until a connection is established (again respecting the collapse key rules). When a connection is established, FCM delivers all pending messages to the device.

Can I register devices from a backend or only from the apps?

the thing is that we already have a backend that handles all the push notification process. From device registration on our DB and notification handling on the device and notification sending to Apple and Google servers...Looking into Parse I saw that it has a lot of things that will take us a lot of time to develop but mostly on the process that sends the notification to the devices.
So...I need to know if devices can register in our backend, then from our backend to Parse and then send push trough Parse. Is this possible? Image below.
Thanks!!
Yes this is possible. You'll need setup your push certificates with Parse and register each device's push token with a Parse Installation object's deviceToken field for it to work. All this is documented on their web site. You'll need to setup a Parse User object for each user as well as each Installation is associated with a single User.

Push notification IOS/Android

I am writing back end for mobile app, we are sending pushes (something like one user add
another to buddies) he should accept it or decline via push notification(it is required), server got some feedback from notification, and do something.
I am familiar with two techniques about pushes, first I push directly on device using token, second is abstraction when user subscribes for channel and I send push notification on this channel. Id in my application is email, and I suggest to update device token in the database each time user login, and send push on it, but how should I identify device OS ?(IOS/Android)
1) How to scale it, if user have multiple devices, and when user will logout, and login from other device ?
May be there is common solutions for this problem.

APNS Push Requests are successfully sent but passes are not updating

I have an app set up to generate passbook passes. The successfully install on the device and I can do manual (pull-down) updates.
Next I began to implement APNS. I'm using the enhanced request method to connect to the production environment, sending in an empty payload (as required) and it returns no error codes when I request a push notification, but my pass never updates and I see no requests hitting my server. I'm using my own device to test until I can get see an update for myself. No pass updates are received.
I then implemented the Feedback service in the hope that it might tell me something. I noticed this. If I pass in the push token, I receive a response which indicates that the device is not receiving notifications (even though the pass is set for automatic updates). The pass is not updated.
I'd appreciate any info into why the the push notifications do not seem to be arriving.
Thanks.
-Erich
One gotcha to check is that you are not using the sandbox APNS server. All Passbook push requests should be sent to the live APNS server.
Try enabling the additional logging option from the PassKit section of the Developer Settings on your device then connecting your device to Xcode and monitoring the console as you send the push. If the push is received, then you should be able to see your device requesting the serials to be updated from your webservice and you should also see your server's response.
Assuming you send a serial and that it matches the serial installed on your device, you should then see the device requesting the updated .pkpass bundle.
If no push is received, try toggling automatic updates on and off while monitoring the device console. It could be that the device is not receiving a valid registration (201) response or that you are using a stale token - you'll be able to see these via the console.

sending ios push message without user action

I want to collect device attributes and send them to the mdm server using push notification.
Steps involved are:
create a configuration profile with mdm payload
get device token
use apple push notification service to send a notification to the device.
get back device attributes
do same with multiple devices which the company manages
Questions:
Will the user always need to act on a message or I can send a message onto the device without user action and get the work done?
Do I need an app on the device to send back the token?
It sounds like you're trying to use push notifications to poll iOS devices and return information.
Push notifications do not provide a mechanism to execute code on a device without user interaction. You would have to have an application loaded on the device, and the user would have to click through from the notification to your app.
In iOS, applications generally don't run unless the user is actively interacting with them. There are a few exceptions (e.g. background audio.)
You do need to have an app running to get the device token. You call registerForRemoteNotificationTypes. See APNs docs for more information.
Edited to add more information:
Looks like the MDM protocol uses push notifications to do just what you describe. However, there's nothing about it in Apple's "Local and Push Notification Programming Guide" (linked above).
Apparently Apple keeps tight control over the MDM documentation (see here and here).
However, I did find this paper from blackhat describing how the system works.
My earlier point about not executing arbitrary code on a device without user interaction still applies. There's a finite set of commands that can be executed (see Appendix A).
I came across this question when searching for iOS push notification access payload without user interaction - Just want to add that, in iOS 7 and above, it is possible to send silent push notifications to app, and app can process them without user interaction.
However, I've also found some discussions saying that the silent push notifications are not delivered reliably, in this SO post. That's why I'm still looking for alternate ways to retrieve payloads of the normal remote push notifications. Doesn't look like there's a way.

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