I am learning how to implement the GCM both from client side (Android) and from server side (ASP.NET). I spent a bit of time on reading the whole google documentation related to GCM and I also tried the sample that they provided.
Because I need to integrate the GCM in an already existing app, I would like to know some specific stuff.
As I got it, the registration id is a token which ties the app on a specific device to the GCM service and the app server; so, the backend can send downstream messages directly to that device.
In my scenario, I could have multiple users who can use the app on the same device, that means they need to login in the app and they have an account on a database in the server side. Do I need to store a different registration id for each user on that device? Or still the registration id refers to only the app?
And what about the same scenario but distributed on multiple device, because a user can have multiple devices?
Thanks in advance.
This relates a lot to the context of your app and what you want to do with notifications
Having one registration ID per device will be okay.
I manage my multiple users by using subscription tags handled by my server.
So take the scenario if you have a sports app:
User A & User B share the same device. Each user subscribes to a tag.
User A is subscribed to two tags (Basketball & Football)
User B is subscribed to two tags (Tennis & Basketball)
When User A logs out you clear the tags associated with that user and when User B logs in you fetch his/her tags.
Your server knows notifications to send to the device based on the tags the user has subscribed for.
Multiple device scenario:
The same goes, when your user logs In you get their tags. The device also has its own token from GCM.
The registration id is the app's id, it may be changed if app version was updated. Your push notification will be sent on device with your app, regardless user account. So every user on every device will receive your notification, you must store only one refistration id per device.
For multiple users: If your messages are user specific, you would want to retrieve the user's token and subscribe to it only while they are logged in. When you switch users remove/unregister the previous token, then save/register the new user's token.
You should not only do this if you have multiple users per device, but when a user signs out. This will prevent user-specific messages being shown at wrong times to wrong users.
For multiple devices: it sounds like you are looking for Device Group Messaging.
With device group messaging, app servers can send a single message to multiple instance of an app running on devices belonging to a group. Typically, "group" refers a set of different devices that belong to a single user.
This is also nice because of the collapse_key. When one of the devices on the same account opens a notification, it will dismiss the notification on the other devices..
Related
I have some doubts about implementing Firebase Cloud Messaging in my app.
My app is a chat similar to whatsapp and facebook messenger. Right now every time someone logs in I register the token and relate it to the user. So if someone wants to chat to an user the app searches the Db for the user ID and there I have his token.
I'm able to register the device token but I'm not sure when should I do that.
In my chat users register through a mail/password signup and is possible that an user could login in other device.
For example:
User Frehley uses a Galaxy 8 and is able to chat and receive notifications in his device using the token. But lets say that he loges in another device. I need to register the token again and relate it to him right?
So, maybe I'm wrong but the best moment to register the token is every time the user logs in and replace it in the DB. Right?
Now, lets say two users (Frehley and Stanley) uses the same Galaxy 8 to login, the token will be diferent everytime the login or it is the same for every single device?
This all depends on the use-case:
If the same user is logged in to two devices, do you want them to receive the notification on both devices? If so, you'll need to store multiple device tokens per user and send the notification to each token for the targeted user. You could also use a device group to identify the devices for a single user. From those docs:
With device group messaging, you can send a single message to multiple instances of an app running on devices belonging to a group. Typically, "group" refers a set of different devices that belong to a single user
If you want the user to only receive the notification on the device that they were last using, you'll have to associate a single token with each user and overwrite that when they start the app on a device. Not that this is not necessarily when they log in, but more likely when the app detects that they're authenticated.
If a different user uses the same app on the same device (using the same device profile), you probably want to stop sending to the device token. The most robust way to do this is to remove the association between the previous user and the token, but that may require that you keep a mapping from token to UID. An easier way is to delete the device token when a user signs out. Then the new user signs in, they will then get a new token.
I'm working on a doorbell project in which I want to send Push Notification to user when a guest come and ring the doorbell, it should send a Push Notification to the user (i.e owner of house). I want to use Firebase Cloud Messaging for this in my android app.
We are using RaspberryPi as the hardware controller. It will trigger notification to user using FCM on their android device when someone presses their doorbell.(which is not a point of concern.)
My confusion is:
According to this post on SO, FCM will send Push Notification to the predefined 'registration_ids' which we have mentioned in the app.
But in my case, every user will have their different registration ids. Also the number of users are not fixed.
It could be any number of users. Whoever uses the doorbell will have their own id.
So it will be a possible scenario like:
suppose I have not mentioned any registration id in app. 10 users have installed this doorbell at home and someone on the house no 1 presses doorbell button, the FCM will send push notification to all the 10 users. Reason is, the registration id will be same for all the devices who have installed app from PlayStore.
suppose I have mentioned 3 registration id in app. So 3 users will be getting the same Push Notification at the same time.
And if i'm not wrong, if i put only 1 registration id, only 1 user will get notification even if 5 different house's doorbell are pressed, the same user will be notified 5 times.
If i declare a specific registration id to be notified in server side (i.e RaspberryPi), I have to regularly add new registration ids as the number of users increases in my app and update it frequently.
So how do I resolve this problem ?
I haven't started developing this app till now because I'm confused with the first step itself.
If I've gone wrong somewhere, please guide me as I'm new to Push Notifications or FCM. I may not have understood concept of FCM, which is possible but I'm not sure. If this solution is not possible using FCM, suggest me some other options to achieve this please.
A Registration token corresponds to a single app instance (see my answer here).
In your post, it seems like you were confusing the registration id as something that is permanent in the app, which is not.
Whenever a user installs your app, on the first initialization, it should generate it's own Registration token, where you'll have to save that token to your App Server, making sure that you associate it with the corresponding user details.
For your use-case, you could make use of Topic Messaging, where you simply subscribe the user to their corresponding doorbell topic, and every time that specific doorbell is triggered, you send a message to the corresponding topic.
I want to build an Android app that allows a user to send notification and data messages to other users. I've started using Firebase only recently, and Firebase Cloud Messaging is still pretty confusing to me.
I have already implemented sending a message to a specific device using the Firebase Instance Id. However, in my app, a user can log out and log into their accounts using different devices, so this isn't really what I want. I read the documentation and it's pretty confusing, they mention sending messages to user groups, and topics (which only apps can subscribe to, not users).
Is there a way to send a push notification directly to another user or a group of users using only their UIDs? If not, is there any other way I can implement this?
I did it storing the FCM Token in a device structure by user. When the user login, add the deviceData to the userToken structure. You need clear deviceData when the user logout. This way, you will only send notifications to logged devices.
Ex (This is not like mine structure, but it can help you to wondering a good way to do this):
-userToken
-idUser1
-device
-idDevice1
-fcmToken: "xxxxx"
-idDevice2
-fcmToken: "YYYYY"
Hope that I helped you
Alright, so to make sure this works across multiple devices when a user logs in, I just make the device subscribe to a topic with the name equal to the user's UID. Now if I want to send a notification to a user, I just send an FCM message on the topic with the name equal to the user's UID!
Example: If my UID is equal to "asdf", whenever I login using multiple devices, each of the devices automatically subscribes to the topic with name "asdf". So now, if I send an FCM from the server on this topic, all the devices from which I am logged on to obtain this notification.
I have a android client app, a server side in django and now I am adding push notifications with GCM.
In my app I have users that login/logout, so I will have a table in my database with devices ids coupled with users, so that every time I want to notification a user, I will lookup its device id and send the notification.
my question is:
When is best to register the Device to the GCM?
When to add the Device to my Server side database?
In the Google Docs it says you should do it once, when the app is installed.
Because I have users in my app, and I want to couple a user with a device in the database, when the app is installed there still isn't a user to associate the Device with.
After the user installs the app, he can register, login and so on.
So when you think is best to register the Device to the GCM and to my server side?
Should it be with a user or only associate it later?
Thanks a lot!
My suggestion would be:
Register the device immediately after the first execution
Save device id somewhere accessible anytime by the app
Couple the id with user details after registration
With this approach you will be able to handle issues if something goes wrong with the registration process and send a notification to the device even if the user is not registered.
EDIT:
You should also implement a strategy to check on a regular basis if the association between the user and the device is still valid or needs to be updated
I'm looking to create for my app some authentication. This will basically consist of a user registering (preferably with their google account, although not necessary) and providing a username that is then sent to my server and then having the ability to log in. I then from there would like to be able for the client app to communicate with my server by sending data and receiving push notifications via GCM (google cloud messaging). It is important that the server is able to send a push notification directly to a certain user not to all registered devices.
Would someone be able to point me in the right direction for what I must do? I've had a look at a few tutorials but what I've seen has always sent messages to all registered devices not to a specific user.
Some extra information about the app:
-The client app (user) will need to send a piece of information to the server. This information will also include the user that it needs to be sent to. Once the server receives the piece of information it should send a push notification through GCM to the specified user's client app.
I'm clueless as to how I need to go about setting up the authentication system, any help would be very appreciated!
Thank you very much,
Daniel
Offcourse you can send push notifications to selected users. This process would roughly comprise the following steps:
1) send the User's GCM registration id to your own server along with a unique user id (what ever id you have assigned to that user; could be email or sim id or something like that). Save it in your database.
2) To send Push notifications to selected users, choose users from the database based on some criteria, retrieve their GCM registration ids from the database and forward them the GCM server.
but there is one important thing you must handle. GCM registration ids could change e.g if user uninstalls and re-installs the application. You must update you corresponding database entry in that case.