Firebase云功能触发FCM，但请求缺少必需的身份验证凭据

Question

I am trying to use firebase-admin inside a firebase cloud function to send a message via firebase cloud messaging (FCM).

When reading through the documentation it says

To use the Admin FCM API, you must first follow the steps in Add the Firebase Admin SDK to your Server.

But I think this is not required since I'm only using cloud functions?

Anyway, it all works up until the point of admin.messaging().send where I get this error:

Error sending message: { Error: Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.
    at FirebaseMessagingError.Error (native)
    at FirebaseMessagingError.FirebaseError [as constructor] (/user_code/node_modules/firebase-admin/lib/utils/error.js:39:28)
    at FirebaseMessagingError.PrefixedFirebaseError [as constructor] (/user_code/node_modules/firebase-admin/lib/utils/error.js:85:28)
    at new FirebaseMessagingError (/user_code/node_modules/firebase-admin/lib/utils/error.js:241:16)
    at Function.FirebaseMessagingError.fromServerError (/user_code/node_modules/firebase-admin/lib/utils/error.js:271:16)
    at FirebaseMessagingRequestHandler.handleHttpError (/user_code/node_modules/firebase-admin/lib/messaging/messaging-api-request.js:125:50)
    at /user_code/node_modules/firebase-admin/lib/messaging/messaging-api-request.js:113:23
    at process._tickDomainCallback (internal/process/next_tick.js:135:7)
  errorInfo: 
   { code: 'messaging/invalid-apns-credentials',
     message: 'Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.' },
  codePrefix: 'messaging' }

This is my source code of the cloud function

import * as functions from 'firebase-functions'
import * as admin from 'firebase-admin'

admin.initializeApp(functions.config().firebase)
const firestore = admin.firestore()
firestore.settings({timestampsInSnapshots: true})

exports.notification = functions.firestore
  .document(path)
  .onUpdate(async (change, context) => {
    const deviceTokens = ['deviceToken-123123123']
    deviceTokens.forEach(token => {
      const fcmMessage = {
        notification: {title: 'test title', body: 'test body'},
        token
      }
      admin.messaging().send(fcmMessage)
        .then((response) => {
          // Response is a message ID string.
          console.log('Successfully sent message:', response)
        })
        .catch((error) => {
          console.log('Error sending message:', error)
        })
    })
  })

The device tokens are stored in firestore and retrieved from firestore inside this cloud function as well. The format of the device token is correct. I have replaced it with a placeholder for this example.

I also looked around for similar questions, but the only one I could find was this one

Answer 1

After much searching I found an error list by firebase and on this list I traced the error code 'messaging/invalid-apns-credentials' which said:

A message targeted to an iOS device could not be sent because the required APNs SSL certificate was not uploaded or has expired. Check the validity of your development and production certificates.

So I figured, I haven't set up my "production" certificate yet, and maybe my cordova dev build is being treated as production build! So I just went ahead and added the production certificate, also deleted and re-added the dev certificate to be sure, and it worked.