通过云功能使用其UID向多个用户发送FCM通知

Question

i have users Uid in an 'users' array as ['uid1','uid2'] now i will be sending notifications to these users in cloud function?

        exports.sendNotificationFromCr = functions.database.ref('/cr/{crUid}/notifications/{notificationid}/').onWrite(event => {

    const uid = ['uid1','uid2']; // some how i get this.
    // some work to send notifications
    // to all tokens of uid1 and uid2.    
}

here is the database structure:

users/
   uid1/
      name:{name}
      FCM-key/
         token1:true
         token2:true
   uid2/
      ...
      FCM-key/
         token3:true

using ['uid1','uid2'] i want to send notification to all 3 tokens in my database. how to do that?

Answer 1

If you're using something like firebase. Then you would want to have a notifications database model, that has the userId, the notification title, body and perhaps image, also a seen flag (true or false).

You would then post notifications either from your clients or from your cloud server code into the database. One per client/notification. If you have thousands of users you would use some sort of server-side cronjob, to offload this so that it runs outside of say your client to server API.

On the clients, you would be listening for new rows in that model filtering on the userId and when they appear, display them to the client in your UI. Once the client has seen the notification you would mark it as seen on the client.

Without knowing what platforms, code base, DB you are using it's impossible to explain in code terms how this would be done.

There are various API's for IOS and Android and Firebase that resolve this.