firebasefirebase-authenticationfirebase-cli

SignInWithCustomToken with auth emulator returns auth/invalid-custom-token

I am trying to auth using emulator with a firebase custom token sent from functions to a web page.

But it returns a HTTP400 from www.googleapis.com when i use it with signInWithCustomToken();.

/** BACKEND SIDE **/
  const token = await createFirebaseToken(userid);
  res.status(200).send(token);

/** FRONTEND SIDE **/
  const res = await axios.post(endpoints.signin,{/* oauth data*/});
  await document.fApp.auth().signInWithCustomToken(res.data); /* HTTP400 here */

The custom token is decoded as below:

{
  "https://identitytoolkit.googleapis.com/google.identity.identitytoolkit.v1.IdentityToolkit",
  "iat": 1605605206,
  "exp": 1605608806,
  "iss": "firebase-auth-emulator@example.com",
  "sub": "firebase-auth-emulator@example.com",
  "uid": *userid*
}

Is it supposed to send to googleapis.com rather than the local emulator?

I did set firebase web config with authDomain:"localhost:9099", and used powershell env to point GOOGLE_APPLICATION_CREDENTIALS to a service-account.json, throw me a warn on startup though:

Your GOOGLE_APPLICATION_CREDENTIALS environment variable points to ***. Non-emulated services will access production using these credentials. Be careful!

Get also this warn 3 times when i call admin.auth().createUser(), dunno if that's related:

Received service account token strange token not from service-account.json Assuming that it owns project *** my project-id ***

Solution

  • Forgot to set

    firebase.auth().useEmulator('http://localhost:9099');

    as stated in the documentation.

    Now customToken are sent to the emulator.