Is it possible Sync Android app with Google Cloud Messaging - android

I have read the GCM detail from Google WebSite and watched the Google IO Video.
But in the Video and GCM Documentation there is example GCM Send one same message to multiple android devices. But in my app I don't want to send the same message to multiple android device.
For Example
I have two android devices with different google account and I want to Sync Notes in app with GCM.
First device register with one#gmail.com
Second device register with two#gmail.com
First device have different Notes. and
Second device have different Notes
If I update notes on server for first device. I want it will Sync with first device(one#gmail.com) not with Second device(two#gmail.com)
Is it possible with the GCM.....? please Let me know.
Thank you

Yes, each instance of you application running on each device will have a unique registration id
Registration ID: An ID issued by the GCM servers to the Android
application that allows it to receive messages. Once the Android
application has the registration ID, it sends it to the 3rd-party
application server, which uses it to identify each device that has
registered to receive messages for a given Android application. In
other words, a registration ID is tied to a particular Android
application running on a particular device.
When your application on a particular devices registers for GCM, it receives a unique registration ID. This registration ID is received after the GCM registration is successful. You can use this registration id (unique to one#gmail.com and one particular device) to send the message to that app+device combo only.
A 3rd-party application server can either send messages to a single
device or to multiple devices. A message sent to multiple devices
simultaneously is called a multicast message.
For example
Content-Type:application/json
Authorization:key=AIzaSyB-1uEai2WiUapxCs2Q0GZYzPu7Udno5aA
{
"registration_ids" : ["APA91bHun4MxP5egoKMwt2KZFBaFUH-1RYqx..."],
"data" : {
...
},
}
the above code sends the message to one instance of your app running on a particular device

Related

How Android GCM works?

I was wondering how android push framework is able to distinguish data recieved via GCM and forward it to the appropriate android application for which it was intended ?
Can anyone let me know how it is done ?
You question : how android push framework is able to distinguish data recieved via GCM and forward it to the appropriate android application.
From your question it looks like you willing to know about data
workflow & Client Server architecture that exists in applications
which are using the GCM service.
As per google’s documentation “Google Cloud Messaging for Android (GCM) is a service that helps developers send data from servers to their Android applications on Android devices”. GCM is a service provided by Google for developer that helps developer to send data from server to any number of Android devices.
Simplified Application Specific Work-flow:
The push notification can be broadcasted either to the mass audience
or a select set of users. Mass audience is targeted when the
notification has to be sent about a marketing campaign. A subset of
users are targeted when a personalized information has to be sent.
The below steps explains how push notification works on android devices:
First android device sends sender id, application id to GCM server
for registration.
Upon successful registration, GCM server issues registration id to android device.
After receiving registration id, device will send registration id to our server.
Our server will store registration id in the database for further use.
Whenever push notification is needed, our server sends a message to GCM server along with device registration id (which is
stored earlier in the database).
GCM server will deliver that message to respected mobile device using device registration id.
This can also be understand using following figure
An Example Workflow:
So, from above images it easy to understand that whenever the android
application is first installed by the user, then it registers itself
to GCM server, and obtains unique GCM ID, then it's our Host servers
responsibility to keep this newly registered Registration ID of the
android user into Database, and then it will be used whenever server
side application willing to send the message to that particular
android user.
So, let us consider one case; suppose an Server wants to send Some data to Android User, which has already registered it's GCM ID 1234567 when it's first time installed, and as it's in the server's database the server application will fetch it from DB, and simply make a HTTP POST request to the GCM server in JSON format, which will have registered user's GCM ID along with the data to send , in same way the GCM Server has the record of all the Registered GCM/Android Clients, it directly forwards that message to the intended android user, and android app in user's phone will raise and Notification alert, to indicate an push notification has arrived.
Hope This answers an question!
GCM stands for Google Cloud Messaging.
Every push notification receive on any Android device is sent by the GCM only.
sender -> GCM -> Android Device
when sender sends an push notification then it goes to GCM. GCM receives that push and forward it to particular Android Device by its Unique device id.
GCM can't deliver Push without Unique Device ID.
while implementing push notification there are two important things, application key and server key ... these are unique Keys.. using these keys GCM identifies the application to whom push notification is related

Steps to receive GCM push notification message from app server

We are developing apps both in IOS and Android. GCM push notification has been enabled for IOS and its working fine now. The package name for both the platforms are going to be the same.
I was given SERVER API KEY and SENDER ID by ios developer to set up gcm for android. While looking for the steps, I came across https://developers.google.com/cloud-messaging/android/client.
I kept to myself that the steps listed in the contents need to be done to set up GCM for android (please correct me if I am wrong).
Get Config file and add it to Android project
Set up Google play services (I added gcm in my project dependency)
Add entries to Manifest file
Check for google play services APK
Obtain registration token.
"An Android application needs to register with GCM connection servers before it can receive messages"
"The client app should store a boolean value indicating whether the registration token has been sent to the server." - My backend team told me I dont need to send them anything I have to just configure gcm in the app and the app will receive messages from backend.
So, My question is Do I need to have RegistrationIntentService and MyInstanceIDListenerService. Also, Do I have to define my InstanceIDListenerService in Manifest?
Our backend uses device id to send push notifications to devices so they dont need registration token to be sent to them as we send device id. So in this case, Should I register my app with GCM using RegistrationIntentService and InstanceIDListenerService? if so, should the app keep the registration token with itself. Is this registration needed?
GCM supports three types of downstream (server-to-client) messaging: send to a specific device (also called "simple" or "targeted"), send to a topic, or send to a device group. Your question says, "our backend uses device id to send push notifications to devices". It is not clear what "device ID" is and which type of messaging you intend to use. Your backend team has told you that you "don't need to send them anything". If that is true, I don't know where they are getting the "device ID".
Each of the three types of messaging provided by GCM require client devices to register with GCM and obtain a registration token. To send a message to a specific device, the registration token is effectively the "device ID". So yes, you need to implement something similar to the RegistrationIntentService and InstanceIDListenerService described in the documentation.
The description in the documentation about needing to send the registration token to the App Server is misleading. That is only required for targeted messaging. The documentation for receiving topic messages states: "Note that, for topic messaging it's not required to send the registration token to your app server; however, if you do send it, your server can verify the validity of the token and get more information about the app that created it."

PushSharp Device ID for Android

All,
I'm probably asking a very basic question here, but how does one get your device ID for PushSharp in Android? My setup is VB.net, and we'll be sending to a large number of different Android devices.
Following the PushSharp example here is my code so far:
push.RegisterGcmService(new
GcmPushChannelSettings("YOUR Google API's Console API Access API KEY for Server Apps HERE"));
push.QueueNotification(new GcmNotification().ForDeviceRegistrationId(
"DEVICE REGISTRATION ID HERE")
.WithJson("{\"alert\":\"Hello World!\",
\"badge\":7,\"sound\":\"sound.caf\"}"));
I know the API key is from the GCM service, but where does the Device Registration ID come from? Is that setup by the GCM service? Or is that something the android device sends the server should save?
Thanks for the help.
The registration ID is assigned by the GCM service. When the application registers to GCM, it gets a registration ID and should send it to the server.
Registration ID An ID issued by the GCM servers to the Android application that allows it to receive messages. Once the Android application has the registration ID, it sends it to the 3rd-party application server, which uses it to identify each device that has registered to receive messages for a given Android application. In other words, a registration ID is tied to a particular Android application running on a particular device.
You can read more about it here.
In case you ended up reading this post and could not get yourself sorted out with the selected answer, here is the ultimate link that helped me:
Getting a GCM registration ID

How does server locate GCM (Google Cloud Messaging) registration IDs

I am trying to write an application which notifies a cellphone using GCM. I was able to implement basic functionality, but there is one question I'm still unsure of
As I understand, the flow goes like this:
Device start up
Device registers, obtains registration id
Server gets the knowledge of registration id on device
Server is using it's API key + registration id to send payload to device
Device receives payload.
One thing which is unclear to me is: what is a proper methodology to implement step #3?
I could not find any way to obtain a list of registered devices. Lets imagine, I am using GCM for a purpose of posting to a known device, and I could email that ID to myself and then register it on the server manually. But as I understand, it expires.
So, it there an expectation that I have to keep re-registering and somehow notifying server every time it happens?
Yes, your app on device must send registration ID to your server application in order for server to be able to send GCM messages. See third point in Enabling GCM.

C2DM registration ID clarification

I am new to C2DM. I have few question about C2DM registration ID.
I have installed same C2DM Mobile app in two devices. Whether I will need two rigistrations ID for two devices or we need one registration ID for mobile client.
My requirement is I have to install client app in two devices and I need to notify both the devices same time when I changed data in Server.
Suggest me the RegistrtionID implementation.
each device can register separately and will receive a separate registration id. When it's received, you'll send the registration id to your application server.
However the registration id is stored on your server, you'll want to send separate notifications for each device that you want to receive a notification (as identified by its registration id).

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