My exact question is that
is an app listens from the notification
server in android.sevice?
Is this mean that every app has its own
notification server,my phone listens for
all of those servers?
No, there is single server (theoretically, it can be server infrastructure) hosted by your phone manufacturer (Google, Apple etc). If you as a developer wants to send push notification to your app user's phone, you sends it to this server and do not care how when or if it is delivered.
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I was wondering how the actual request from Server get routed to the Application if the browser is not running. Also, does the service workers maintain an active connection to the server so that it receives the push notification whenever the server publishes something?
I think for every iOS device, Apple keeps a socket open between that device and the Apple Push Notification Service. Which essentially acts as a router for all notifications across all apps and all devices. So your server can send messages to APNS saying "yo, hit up this guy with this message", and APNS will use the socket it has open with every device to send the notification.
Also check out https://developer.apple.com/notifications/.
And https://developer.apple.com/documentation/usernotifications/setting_up_a_remote_notification_server
I know that FCM messages are sent to devices corresponding to FirebaseInstanceId.getInstance().getToken() and on onMessageReceived() the FCM messages are handled according to the need of the User. But if the app is not running and with all the background limitations in Oreo how the OS knows that a message has arrived?
how the OS knows that a message has arrived?
There is a socket connection between the phone and google's FCM server. This connection is shared between all apps on the phone that use FCM.
See here
When you ask FCM to deliver a message to your phone ABC and to the app with id XYZ, google's server will send some data to phone ABC. The FCM component on the phone then finds the app with id XYZ (it has to look up the correct app first because this connection might also receive data for other apps) and deliver the message to id.
This is managed by google so naturally the process doesn't suffer from background restrictions, assuming you set the right priority for your FCM message.
I would like to know what is best practice when operating with push notifications in particular GCM notifications. Where should I ignore the notification from the server side. That is to say the server only send notifications to active users or the client side where the server sends out notifications but the app ignores them based on whether the activity is open or closed.
It's always better to decide at the server side which devices have active users, and only send notifications to them.
The reasons:
You don't want to run any code in the client side if you are not going to do anything with the incoming GCM message, since that would just be a waste or battery life.
It's better to reduce the number of messages your server sends to GCM server, since this way, the devices that should recieve and display the notifications will recieve them faster.
I want to implement Push Notification for an App (both iOS and Android) and need clarifications on the following scenarios.
I understand how the Push Notification works in general and the limitations. I did read the docs but that just got me confused and didnt answer all my questions.
How are the following scenarios handled in iOS and Android:
When the device is turned off
When the device is not connected to 3G or Wifi networks
When the device has crashed and need restart
When the App is in foreground
When the App is in the background
When user is currently using the App
When my app is closed (not opened / launched)
When a push notification is user specific and both users share the same device and app. Example: If a husband and wife share same device and use a bank App with Push notification.
Can you send User specific notification if device is shared by multiple users?
When user has installed App on multiple devices
Can you send a notification to all devices registered by a user at once?
Do you store the device type (iOS or Android) with the registrationID in the User table or is there a way to differentiate the type of device by inspecting the token or registrationID?
Can you cancel a previously sent notification which is not read yet and send a new one?
Is it still true that Android Push Notifications does not work on Kindle Fire and will need to implement Amazon Device Messaging
Anything else that I need to think of or plan? I am aware of handling un-registering and feedback service
I would answer some of your questions, specific to android thought. Don't know about iPhone, If its of similar kind or not.
The device receives notification from Google Cloud server as and
when the notification is triggered by the server and it doesn't have
any relation with application state (Running, Closed, Background or
foreground).
If the notification is sent to a device when its not connected to
the internet ( switched off or not connected to the net) , it gets
notification only when it connects to the network. However, if the device
is crashed and restarted after the notification is received, you
won't get the notification again.
Is it user specific?
It depends on the individual servers implementation.
Do we store device type?
Yes we can.
Can we differentiate the IDs of iPhone and android?
Yes, android Device IDs are longer in length than iPhone's.
Can we cancel an already sent notification?
No, it is a one way communication channel as far as I know.
When the device is turned off:
Answer:
IOS/Android Server (Not your Server) will handled when to send the Push Notification. It checks that device is reachable or not. We can define that how many times IOS/Android Server should try to send Push Notification.
When the device is not connected to 3G or Wifi networks
Answer:
Nothing related to 2G/3G/Wi-Fi. Device should be connected to Internet via any network.
When the device has crashed and need restart
Answer:
IOS/Android Server checks that device is reachable or not.
When the App is in foreground
Answer:
Nothing related to app in foreground.
When the App is in the background
Answer:
Nothing related to app in background.
When user is currently using the App
Answer:
Nothing related to app being used currently.
When my app is closed (not opened / launched)
Answer:
Nothing related to app is closed.
When a push notification is user specific and both users share the same device and app. Example: If a husband and wife share same device and use a bank App with Push notification.
Answer:
It depends on how you have implemented on YOUR Server. You will be managing Device Id for each user. So it's upto your implementation logic to send to same device for multiple users.
Can you send User specific notification if device is shared by multiple users?
Answer:
It depends on how you have implemented on YOUR Server. You will be managing Device Id for each user. So it's upto your implementation logic.
When user has installed App on multiple devices
Answer:
It depends on how you have implemented on YOUR Server.
Can you send a notification to all devices registered by a user at once?
Answer:
Yes again as per your implementation logic.
Do you store the device type (iOS or Android) with the registrationID in the User table or is there a way to differentiate the type of device by inspecting the token or registrationID?
Answer:
Yes you need to store the device type, to identify to which Server (IOS/Android), you need to send request for Push Notification.
Can you cancel a previously sent notification which is not read yet and send a new one?
Answer:
No you cannot cancel the request.
Is it still true that Android Push Notifications does not work on Kindle Fire and will need to implement Amazon Device Messaging
Answer:
Need to google it around.
Anything else that I need to think of or plan? I am aware of handling un-registering and feedback service
Answer:
Need to google it around.
is there a way to determine, if a push notification can be delivered right now?
As far as i know its not possible, but im not sure about it.
So my scenario looks like this:
I have a android app
I have my own server
My app on my android phone should communicate with my app on my friends android phone.
Now im looking for a realtime communication framework and i guess C2DM could help me.
So lets say:
My app on phone A should write a little message to my app on phone B.
Lets assume, phone A is online and can communicate with my server. So phone A would send the message to my server, and my server would now try to deliver this message to phone B.
And thats the point, where my server would try to deliver the message to phone B via C2DM, and thats also the point, where my server needs to know, if its possible to send this message via C2DM or not. Otherwise my server should use another communication way to deliver the message, like sms or whatever.
So the point is, that i really need to know if its possible at this very moment to deliver to Phone B via C2DM (of course my server knows the C2DM Registration ID of Phone B).
Otherwise, for example if Phone B is not connected to the internet and can not receive C2DM push notifications, my server would send a sms to phone B.
Is it possible, to dertemine if phone B is online?
What i try to do is, to reach every user (if his phone is turned on). If he is online, then via C2DM, otherwise via SMS, so that the message is delivered at this very moment in any way.
Note:
I know that C2DM can store notifications and deliver the stored notifications when phone B is online, but thats not the way i want to use it. Note also, that i know (architectural) how to use C2DM. So the "message", that should be delivered from phone A to phone B will not be delivered directly in a C2DM push notification with the message text / sensitive data as message body. Of course the delivered message is only a "update message" to tell my app on phone B, that something has changed and the app should connect now to my server to get (polling) the latest state with the "text message" which has been sent from phone A to you (phone B)
is there a way to determine, if a push notification can be delivered right now?
No. There is no guarantee that a C2DM message will ever be delivered, let alone immediately.
Is it possible, to dertemine if phone B is online?
Phone B can know if it is online. If you implement a server with some sort of long-held socket connection (e.g., XMPP), that server can know if it has an open socket connection with Phone B.