Firebase Functions onCreate method not working on Firestore after getting the userID

Question

I am trying to get the userID of the user and then running a onCreate function on the firestore in Firebase Functions for background notifications, but the onCreate function doesn't run.The function shows its executed and finished.

import { https, firestore, logger } from "firebase-functions";
import { initializeApp, messaging, firestore as _firestore } from "firebase-admin";

initializeApp();
const fcm = messaging();
const db = _firestore();

export const friendRequest = https.onCall((data, context) => {
  const userID = context.auth.uid;
  try {
    db.collection("users")
      .doc(userID)
      .collection("tokens")
      .doc("token")
      .get()
      .then((value) => {
        const token = value.data().token;
        firestore
          .document(`users/${userID}/recievedRequests/{request}`)
          .onCreate((snapshot) => {
            const senderName = snapshot.data().name;
            logger.log(
              "New Notification to " + token + " ,by :" + senderName
            );
            const payload = {
              notification: {
                title: "New Friend Request",
                body: `Friend Request from ${senderName}`,
              },
            };
            fcm.sendToDevice(token, payload).then((response) => {
              logger.log("Response" + response.successCount);
            });
          });
      });
  } catch (error) {
    logger.log("Error : " + error);
  }
});

This is the Friend Request function I want to send notification to user when he receives a notification. My firebase log shows

Answer 1

You have the onCreate() within another function so that's not deployed to Cloud Functions at first place unlike the friendRequest . It seems you are trying to notify a user who has received the request. You can try the following function:

export const notifyUser = firestore
  .document(`users/{userId}/recievedRequests/{request}`)
  .onCreate(async (snapshot, context) => {
    const userId = context.params.userId;
    const senderName = snapshot.data().name;

    logger.log("New Notification to " + userId + " ,by :" + senderName);

    const payload = {
      notification: {
        title: "New Friend Request",
        body: `Friend Request from ${senderName}`,
      },
    };

    // Get Token of the User
    const tokenSnap = await db
      .collection("users")
      .doc(userId)
      .collection("tokens")
      .doc("token")
      .get();

    const token = tokenSnap.data()!.token;

    return fcm.sendToDevice(token, payload).then((response) => {
      logger.log("Response" + response.successCount);
      return null;
    });
  });

To send the request at first place, you can simply add the a document in users/RECEIVER_ID/friendRequests/ sub-collection that'll trigger the above function that'll fetch receivers FCM token and send the notification. There's no need of the onCall() function.