I'm wondering if anyone has faced this issue with Google C2DM? This is the scenario I am faced with:
User installs the app and registers
with C2DM server for a registration
key.
User uninstalls the app.
User reinstalls the app (and
registers with C2DM server for new
registration key).
Now I send message from my server to the user's phone and they get a duplicate message.
Could anyone shed any insight into wether this is expected behaviour or how I can fix it?
Thanks,
Not sure if this is the best approach, but there's a relevant thread over at the android-c2dm group, where the poster offers one technique:
I am sending registration id in the message, so I can check it against the stored registration id on the device.
If it's not the same, discard it and notify the service that registration Id is no longer in use
Downside is sending registration Id takes up some space in already
limited message size. But works perfectly in my case since my
original message is no more than a few chars long.
This should only happen for the first push notification after re-installing your application.
Google C2DM service is working in passive mode when it comes to detecting uninstalled applications.
First push notification after uninstalling your application (without unregistering from C2DM!!!) will NOT return any error in response. However, the second push notification will return an "invalid registration" or "not registered" error codes where you can realize the application was uninstalled.
The reason is that C2DM servers return the response code immediately and only then tries to push the client. When client respond that an application was uninstalled, it is deleted from C2DM servers. Next push attempt will return an error code immediately.
Another solution could be to provide your server with a unique identifier for the device. In that case you can just update the registrationID for that UUID when the device tries to register after re-installation.
Yup, I've run into the same issue and in my opinion it's a big oversight in the Android C2DM implementation. iOS handles this much better in that an app can only ever receive notifications for one and only one device token (equivalent of the c2dm registration id)
The workaround I use is to send the last 10 characters of the registration id as part of the c2dm payload and then in my onMessage method I do the following check:
if (!regId.endsWith(bundle.getString("regsuffix"))) return null;
Both #Zamel and #johan answers are good and need to be combined. If you combine both solutions than you will minimize your server's database.
So the best solution will be to:
Send device id when sending the push token to the server
Update push token when is sent for existing device id
Invalidate push token in the server's database, if push notification returns an "invalid registration" or "not registered" error codes to the server
When push token is recognized as "invalid registration" or "not registered" you can invalidate it(mark it as null), delete the row in the database or implement expiration functionality. It depends on your needs
Related
My app is using Google's C2DM (push notification) to notify users about new activity from friends. Once they install the app I register the device with C2DM servers and store user's phone number. So I know that the user is using my app and I can send him/her the push notifications. But what happens if users uninstalls my app, is there a way to catch it in my app? Or the only way is to catch an error on my server when I send a C2DM and it's unreachable, then mark a user as inactive?
I would love to notify users when their friends are using an app and when they no longer do.
What's is the best solution for this scenario?
The GCM documentation explains this situation here:
https://developers.google.com/cloud-messaging/registration#how-uninstalled-client-app-unregistration-works
"An application can be automatically unregistered after it is uninstalled from the device. However, this process does not happens right away, as Android does not provide an uninstall callback."
Basically when GCM tries to send the next push notification, the device will tell GCM the receiving application was uninstalled.
As for notifying friends that their friends aren't using the app any more, GCM will send a NotRegistered error to your notification server when this failure occurs; it won't be immediate, but could you use that?
Unfortunately the ACTION_PACKAGE_REMOVED intent will be sent out to all receivers except for your own. This is confirmed here.
Some questions for your C2DM plan, since I'm not very familiar with it. If the user just leaves their device off for a long period of time, will that trigger the error condition you use? How does C2DM actually report an "unreachable" device? Is that a condition that only occurs when it attempts to send the push notification and fails or is it when it somehow determines it reaches the device but fails to be handled properly? Obviously in the second scenario your plan would work, but I can see some "false positives" occurring otherwise.
Older SO question for reference: android not receiving Intent ACTION_PACKAGE_REMOVED in the removed package
Yes, but it is quite hacky.
The method is based on the fact that the first thing android does when uninstalling your app is deleting your data file. So you could use a file watcher to detect the deletion.
Also you need to write this in native code. If you write your code in java, your app will be uninstalled before it could execute any code.
please see this demo : https://github.com/sevenler/Uninstall_Statics
Google C2DM service is working in passive mode when it comes to detecting uninstalled applications.
First push notification after uninstalling your application (without unregistering from C2DM!!!) will NOT return any error in response. However, the second push notification will return an "invalid registration" or "not registered" error codes where you can realize the application was uninstalled.
The reason is that C2DM servers return the response code immediately and only then tries to push the client. When client respond that an application was uninstalled, it is deleted from C2DM servers. Next push attempt will return an error code immediately.
I have some points to tell you ,
Android community recommends you to use GCM instead of C2DM as it's no longer available.
In android there is no way for applications to get itself notified that app is getting uninstalled.
in GCM if you want to stop sending messages to uninstalled apps you can refer this
When you send messages to GCM from your server you will get response string.In that if you are getting error as "NotRegistered, you should remove the registration ID from your server database because the application was uninstalled from the device or it does not have a broadcast receiver configured to receive com.google.android.c2dm.intent.RECEIVE intents."
I know only one way with server response 200 with "NotRegistered" message in body.
NotRegistered — The registration_id is no longer valid, for example user has uninstalled the application or turned off notifications. Sender should stop sending messages to this device.
Look into this GCM doc:
GCM Unregistration
You should never unregister your app. This is taken care from server side.
To detect app uninstallation using Google Play Services, you can use the App Uninstallation Reporting API. This API allows you to receive notifications when your app is uninstalled by users. #ThanksChatGPT
Scenario: I have a 3rd-party app server, a gcm http connection server, and an android app setup for push notifications. When the user uninstalls the app, I can delete them from my 3rd-party server by sending their (no-longer-valid) registration id a push notification and handling the "NotRegistered" error returned from the gcm connection server.
However, this similar approach does not seem to work when you send a push notification to users subscribed to a "Topic", as here the gcm connection server only returns a json object with the "message_id".
The notable columns in my 3rd-party server database table are as follows:
| gcmRegistrationID (string) | subscribedToNotificationTopic (boolean) |
Does anyone know how to identify a user that has previously set true in the subscribedToNotificationTopic column, then uninstalled the app?
I have an idea on how to resolve this, but it seems somewhat messy.
Every so often, instead of only sending push notifications to a topic e.g.
{
"to" : "/topics/global",
...
}
send a push notification to the registration ids of the users subscribed to the topic e.g.
{
"registration_ids" : {list of registration ids},
...
}
such that I can retrieve and handle any "NotRegistered" errors.
The problem with this however, is that multicast messaging has a limit of 1000 users so I'd have to send a message for each thousand.
This seems like bad practice (especially if there is more than one topic involved), but maybe it's the only way?
(Extra tags: topic messaging, pubsub, unregister, google cloud messaging)
First off, I am not sure it is correct to assume that an "NotRegistered" error can only be the result of the user uninstalling your app. It seems like the device can become unregistered if the device receives a message but that message can not be delivered. This can happen if the user stops the app (which is different from uninstalling it, or even if the app was killed and remains stopped due to a power saving mode.
https://developers.google.com/cloud-messaging/ccs#response
If it is NotRegistered, you should remove the registration ID from
your server database because the application was uninstalled from the
device, or the client app isn't configured to receive messages.
What you can do is from the device side, periodically register the device, and make sure that the token you get back is the same as the one you stored, if not update your server with the new token.
As far as detecting if a user has uninstalled your app via a response to a topic message, I agree with you it does not seem to be directly possible. As an alternative to your proposed solution, you might, every now and then include a flag in the topic message that would ask the device to validate itself with your server, if a device does not validate itself after some number of attempts or some period of time you might conclude the user is not longer listening.
The other question is why do you really need to know. Is there any harm in sending some extra regid's to google? If a user quits your web service you can remove them from the list, but do you really need to take action if they just un-install your app from there device? - Just some thing to consider. Hope this helps.
I have built and Android app (not in the Market yet) and I am struggling to figure out why C2DM is failing. I am able to register my device, and I get back a registration Id.
I have built a server app that submits the request to google's C2DM server and I get back a 200 response and a message id. (Success). The issue is, my device never gets the messages.
One of the things that surprises me is that if I try to register a device twice within seconds I get back a different registration id. Most likely they use time as a seed.
Is it normal for this registration id to change so frequently? Any clues / advice (I read the guidelines already)?
Cheers...
Note:
I do not have a sim card and all I use is a corporate WiFi network. My last hope is that maybe port 5228 is closed on my network.
Google says that C2DM will change anytime. So you have to update your server with the correct registration id for the device. If the id server has doesnt match the one which google sent to your device, it will not be able to deliver the push.
So as a golden rule, "always update the server with the latest c2dm registration id as soon as you get it"
if Google replies with 200, the body should contain an id. if there is an error, there will be an error in the body. the error codes are given below.
QuotaExceeded — Too many messages sent by the sender. Retry after a while.
DeviceQuotaExceeded — Too many messages sent by the sender to a specific device. Retry after a while.
MissingRegistration — Missing registration_id. Sender should always add the registration_id to the request.
InvalidRegistration — Bad registration_id. Sender should remove this registration_id.
MismatchSenderId — The sender_id contained in the registration_id does not match the sender id used to register with the C2DM servers.
NotRegistered — The user has uninstalled the application or turned off notifications. Sender should stop sending messages to this device and delete the registration_id. The client needs to re-register with the c2dm servers to receive notifications again.
MessageTooBig — The payload of the message is too big, see the limitations. Reduce the size of the message.
MissingCollapseKey — Collapse key is required. Include collapse key in the request.
This info is from http://code.google.com/android/c2dm/#testing
Yes as Rihan said every time you registered your device you will get a new registration ID.and if you are getting registration ID that your c2dm is successfully implemented from google server.Now you have to send this ID to your server .And by using this ID you have send push notification to your device.
Now you will get message in OnReceive() method of C2DReceiver and you have to handle this message(May you give a notification to user)
The issue was that port 5228 was closed on the network I was using.
I had a similar problem, the issue was in the app I wasn't sending the right email address used to register for the C2DM messaging. So it kept failing.
So check if you are sending the correct email address as the senders email address when registering for C2DM from the device that is the email address registered with google for push notifications.
Although Rihan is correct. The registration id changes every time. The reason why I was not getting the messages is because the port was locked.
For other googlers, make sure 5228 is open before you go mad...
When the user uninstalls the app from his android device, it means that the registration_id for C2DM is no more valid. Now, how does the server which sends the push notifications know this. With Apple, there is something called Apple-feedback which lists out all the device-tokens (Android folks, read as registration-id) that are invalid.
Please, help me out with this.
I'm also looking for a sollution to this, so far I've only found one useful sollution which is mentioned here: http://groups.google.com/group/android-c2dm/browse_thread/thread/8e58ed95a0818716
In short: When you SEND the message to the device, send an UID with it (eg. generated on first install). When a message is received in the application, check if the UID is the same, if it is, do you thing (eg create notification), otherwise ignore it, and send a msg to your C2DM server that this Google C2DM registration ID is not valid anymore.
I think that is the reason C2DM are refreshing the Registration ID after random time. If user uninstall the App from his device, he is not not going to update his/her Registration ID either. Then he will not getting any Push Notifications anymore.
My app is using Google's C2DM (push notification) to notify users about new activity from friends. Once they install the app I register the device with C2DM servers and store user's phone number. So I know that the user is using my app and I can send him/her the push notifications. But what happens if users uninstalls my app, is there a way to catch it in my app? Or the only way is to catch an error on my server when I send a C2DM and it's unreachable, then mark a user as inactive?
I would love to notify users when their friends are using an app and when they no longer do.
What's is the best solution for this scenario?
The GCM documentation explains this situation here:
https://developers.google.com/cloud-messaging/registration#how-uninstalled-client-app-unregistration-works
"An application can be automatically unregistered after it is uninstalled from the device. However, this process does not happens right away, as Android does not provide an uninstall callback."
Basically when GCM tries to send the next push notification, the device will tell GCM the receiving application was uninstalled.
As for notifying friends that their friends aren't using the app any more, GCM will send a NotRegistered error to your notification server when this failure occurs; it won't be immediate, but could you use that?
Unfortunately the ACTION_PACKAGE_REMOVED intent will be sent out to all receivers except for your own. This is confirmed here.
Some questions for your C2DM plan, since I'm not very familiar with it. If the user just leaves their device off for a long period of time, will that trigger the error condition you use? How does C2DM actually report an "unreachable" device? Is that a condition that only occurs when it attempts to send the push notification and fails or is it when it somehow determines it reaches the device but fails to be handled properly? Obviously in the second scenario your plan would work, but I can see some "false positives" occurring otherwise.
Older SO question for reference: android not receiving Intent ACTION_PACKAGE_REMOVED in the removed package
Yes, but it is quite hacky.
The method is based on the fact that the first thing android does when uninstalling your app is deleting your data file. So you could use a file watcher to detect the deletion.
Also you need to write this in native code. If you write your code in java, your app will be uninstalled before it could execute any code.
please see this demo : https://github.com/sevenler/Uninstall_Statics
Google C2DM service is working in passive mode when it comes to detecting uninstalled applications.
First push notification after uninstalling your application (without unregistering from C2DM!!!) will NOT return any error in response. However, the second push notification will return an "invalid registration" or "not registered" error codes where you can realize the application was uninstalled.
The reason is that C2DM servers return the response code immediately and only then tries to push the client. When client respond that an application was uninstalled, it is deleted from C2DM servers. Next push attempt will return an error code immediately.
I have some points to tell you ,
Android community recommends you to use GCM instead of C2DM as it's no longer available.
In android there is no way for applications to get itself notified that app is getting uninstalled.
in GCM if you want to stop sending messages to uninstalled apps you can refer this
When you send messages to GCM from your server you will get response string.In that if you are getting error as "NotRegistered, you should remove the registration ID from your server database because the application was uninstalled from the device or it does not have a broadcast receiver configured to receive com.google.android.c2dm.intent.RECEIVE intents."
I know only one way with server response 200 with "NotRegistered" message in body.
NotRegistered — The registration_id is no longer valid, for example user has uninstalled the application or turned off notifications. Sender should stop sending messages to this device.
Look into this GCM doc:
GCM Unregistration
You should never unregister your app. This is taken care from server side.
To detect app uninstallation using Google Play Services, you can use the App Uninstallation Reporting API. This API allows you to receive notifications when your app is uninstalled by users. #ThanksChatGPT