Firebase admin SDK FCM error Exactly one of topic, token or condition is required

Question

I am fixing an error message which occurred, but it also used to work before. I am sending FCM notification with multiple tokens and am getting the following error

0|api      | 2020-2-11 13:26:26   [ExceptionsHandler] Exactly one of topic, token or condition is required
0|api      |  +542752ms
0|api      | Error: Exactly one of topic, token or condition is required
0|api      |     at FirebaseMessagingError.FirebaseError [as constructor] (/var/www/tokee-api-new/node_modules/firebase-admin/lib/utils/error.js:42:28)
0|api      |     at FirebaseMessagingError.PrefixedFirebaseError [as constructor] (/var/www/tokee-api-new/node_modules/firebase-admin/lib/utils/error.js:88:28)
0|api      |     at new FirebaseMessagingError (/var/www/tokee-api-new/node_modules/firebase-admin/lib/utils/error.js:254:16)        0|api      |     at Object.validateMessage (/var/www/tokee-api-new/node_modules/firebase-admin/lib/messaging/messaging-types.js:46:15)
0|api      |     at /var/www/tokee-api-new/node_modules/firebase-admin/lib/messaging/messaging.js:265:31
0|api      |     at Array.map (<anonymous>)
0|api      |     at Messaging.sendAll (/var/www/tokee-api-new/node_modules/firebase-admin/lib/messaging/messaging.js:264:29)
0|api      |     at Messaging.sendMulticast (/var/www/tokee-api-new/node_modules/firebase-admin/lib/messaging/messaging.js:313:21)   0|api      |     at userChunks.forEach.userChunk (/var/www/tokee-api-new/src/modules/common/firebase/firebase.service.ts:154:42)     0|api      |     at Array.forEach (<anonymous>)
0|api      |     at FCMService.<anonymous> (/var/www/tokee-api-new/src/modules/common/firebase/firebase.service.ts:142:16)
0|api      |     at Generator.next (<anonymous>)
0|api      |     at /var/www/tokee-api-new/dist/src/modules/common/firebase/firebase.service.js:13:71
0|api      |     at new Promise (<anonymous>)
0|api      |     at __awaiter (/var/www/tokee-api-new/dist/src/modules/common/firebase/firebase.service.js:9:12)
0|api      |     at FCMService.sendToMany (/var/www/tokee-api-new/dist/src/modules/common/firebase/firebase.service.js:123:16)       0|api      |     at AdminNotificationController.<anonymous> (/var/www/tokee-api-new/src/modules/notification/admin-notification.controller.ts:65:42)
0|api      |     at Generator.next (<anonymous>)
0|api      |     at fulfilled (/var/www/tokee-api-new/dist/src/modules/notification/admin-notification.controller.js:16:58)
0|api      |     at <anonymous> 

The code producing the error:

async sendToMany(users: User[], notification: VSendNotification, title = 'Title', lowPriority = false) {
    // We split emails into arrays of max. 100 size because of the limitation with FCM
    const userChunks = _.chunk(users, 100);
    const promises = [];
    userChunks.forEach(userChunk => {
      const msg: admin.messaging.MulticastMessage = {
        notification: {
          title,
          body: notification.body
        },
        tokens: userChunk.map(user => user.firebaseToken),
        android: {
          priority: lowPriority ? 'normal' : 'high'
        }
      };
      promises.push(this.app.messaging().sendMulticast(msg));
    });
    const result = await Promise.all(promises);
    let accepted = 0;
    let rejected = 0;
    result.forEach(response => {
      accepted += response.successCount;
      rejected += response.failureCount;
    });

    return { accepted, rejected, notification };
  }
}

Thoughts on what could be wrong?

Answer 1

Solution - Avoid sending empty fcm token to Firebase.

I got the solution. I listed all my firebase token and there were some empty tokens in my database which was the main problem.

When we send empty fcm token, Firebase gives us below error

Exactly one of topic, token or condition is required