Firebase Callable Function + CORS

Question

I'm trying to call a callable Cloud Function from my app, but I'm facing CORS issues.

I can't enable Cors since I don't have access to the request and response on the onCall function. This is my function:

exports.UserInvitation = functions.https.onCall((data, context) => {   const email = data.email     return new Promise((resolve, reject) => {     admin.auth().createUser({       email: email,       emailVerified: false,       password: password     }).then(resolve).catch((err) => {       console.error(err.code)       reject(new functions.https.HttpsError(err.code, err.message))     })   }) }) 

And this is how I call it:

functions.httpsCallable('UserInvitation')({ email: this.input.value }).then((data) => {       console.log('Sent invitation:', data) }) 

Firebase-functions package.json:

{   "name": "functions",   "description": "Cloud Functions for Firebase",   "scripts": {     "serve": "firebase serve --only functions",     "shell": "firebase functions:shell",     "start": "npm run shell",     "deploy": "firebase deploy --only functions",     "logs": "firebase functions:log"   },   "dependencies": {     "bluebird": "^3.5.1",     "firebase-admin": "~5.12.0",     "firebase-functions": "^1.0.1"   },   "private": true } 

WEB SDK Firebase version: 4.13.1

Answer 1

For anybody else who has arrived here searching firebase callable functions cors errors, here's my checklist:

1. Ensure the function is deployed.
2. Ensure the function name is correct. I was calling recalculatY when it should have been recalculateY. Got a cors error for some reason.
3. Ensure the function code itself is not throwing an error. Use the emulator to help. This didn't throw a cors error still helpful to know.
4. Ensure your regions match - I am using europe-west2. I had to both deploy the function with that region, and call it using the region. For a while, I assumed the client would infer the correct region if the function name was correct. That was not the case.

Deploying a callable function to a specific region:

// This is the file in which you define your callable function. const functions = require('firebase-functions'); ... exports.yourFunc = functions.region('europe-west2').https.onCall(async (data, context) => {     ... })  

Calling a function in a specific region from the client (in this case, a vuejs web app):

// In my case, this is a vuex store file, but it is safe to assume this is plain old javascript import firebase from 'firebase/app' import 'firebase/functions' ... firebase.app().functions('europe-west2').httpsCallable('yourFunc') 

Note: firebase.app().function... vs firebase.app.function...