I have this cloud function using node.js that listen every time a child is added on a specific node, then it sends a notification to the users. However when I added something on the database, it does not send anything. I am working on android studio java. Should I connect the function to the android studio, if it will only listen on the database and then send FCM messages on the device tokens.

also how to do debugging on this, I am using VS code.

This is my code:

const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();

exports.listen = functions.database.ref("/Emergencies/{pushId}")
.onCreate(async (change, context) => {
 change.after.val();
 context.params.pushId;

// Get the list of device notification tokens. Note: There are more than 1 users in here
const getDeviceTokensPromise = admin.database()
  .ref("/Registered Admins/{uid}/Token").once("value");

// The snapshot to the user's tokens.
let tokensSnapshot;

// The array containing all the user's tokens.
let tokens;

const results = await Promise.all([getDeviceTokensPromise]);
tokensSnapshot = results[0];

// Check if there are any device tokens.
if (!tokensSnapshot.hasChildren()) {
return functions.logger.log(
  'There are no notification tokens to send to.'
);
}
functions.logger.log(
  'There are',
  tokensSnapshot.numChildren(),
  'tokens to send notifications to.'
);

// Notification details.
const payload = {
notification: {
    title: "New Emergency Request!",
    body: "Someone needs help check Emergenie App now!",
  }
}; 

// Listing all tokens as an array.
tokens = Object.keys(tokensSnapshot.val());
// Send notifications to all tokens.
const response = await admin.messaging().sendToDevice(tokens, payload);
// For each message check if there was an error.
const tokensToRemove = [];
response.results.forEach((result, index) => {
  const error = result.error;
    if (error) {
      functions.logger.error(
        'Failure sending notification to',
        tokens[index],
       error
      );
      // Cleanup the tokens who are not registered anymore.
      if (error.code === 'messaging/invalid-registration-token' ||
          error.code === 'messaging/registration-token-not-registered') {
        tokensToRemove.push(tokensSnapshot.ref.child(tokens[index]).remove());
      }
    }
 });
  return Promise.all(tokensToRemove);
});

CodePudding user response：

This seems wring:

const getDeviceTokensPromise = admin.database()
  .ref("/Registered Admins/{uid}/Token").once("value");

The {uid} in this string is not defined anywhere, and is also going to be treated as just a string, rather than the ID of a user - which is what I expect you want.

More likely, you'll need to:

1. Load all of /Registered Admins
2. Loop over the results you get from that
3. Get the Token value for each of them

If you are new to JavaScript, Cloud Functions for Firebase is not the easiest way to learn it. I recommend first using the Admin SDK in a local Node.js process or with the emulator suite, which can be debugged with a local debugger. After those you'll be much better equipped to port that code to your Cloud Functions.