CODEWITHSUNDEEP
javaandroidfirebasegoogle-cloud-firestoregoogle-cloud-functions
Omar Naji
Omar Naji

Reputation: 1

Firebase - send notification when new new data stored to some users have specific data on database

I want to send a notification when realtime-database have new data to some user who has specific data in Firebase Firestore.

Sample of data that has a relation to the user.

Firebase realtime - post data

and the user has the group what he followed it.

Firebase Firestore - user data

as of now, the specific data is the group name.

easily, send a notification to users who have the same group name as the poster group name

Upvotes: 0

Views: 242

Answers (1)

samthecodingman
samthecodingman

Reputation: 26236

Instead of searching Cloud Firestore for users to notify, you should employ Firebase Cloud Messaging instead. This allows you to subscribe each user to a topic corresponding to the groups they are in.

Because you will need to subscribe each relevant user to their corresponding notification topics, this won't be a simple "drop-in and it works" solution. Consult the documentation for your targeted platforms on how to do this.

import * as functions from "firebase-functions";
import * as admin from "firebase-admin";

export const notifyGroupsOfNewPost = functions.database.ref("/Poster/{postId}").onCreate(async (snapshot, context) => {

  /* avoid using `snapshot.val()` unless you need all of the data at once */
  
  const postGroups = snapshot.child("Groups").val(); // assumed to be parsed as an array, make sure to handle non-array values gracefully
  
  if (postGroups === null) {
    throw new Error('Groups of new post missing');
  }
  
  return Promise.all(postGroups.map((group) => {
    const message = {
      /* note: only send data used for creating the notification message,
         the rest of it can be downloaded using the SDK once it's needed */
      data: { 
        Impact: snapshot.child("Impact").val(),
        Subject: snapshot.child("Subject").val(),
        TT: snapshot.child("TT").val()
      },
      topic: group /* you could also use `${group}-newpost` here */
    };
    
    return admin.messaging().send(message)
      .then((messageId) => {
        console.log(`Successfully notified the ${group} group about new post #${snapshot.key} (FCM #{$messageId})`);
      })
      .catch((error) => {
        console.error(`Failed to notify the ${group} group about new post #${snapshot.key}:`, error);
      });
  });
});

Upvotes: 1

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