How to sign-in as a certain user, under emulation?

[akauppi]

Under auth emulation, signInWithCustomToken used to allow forcing a sign-in as a certain user, simply by providing the token { "uid": "xyz" }. This does not seem to work with 0.900.15 client.

Is this intentional? What should I use, instead?

Attached code snippets, also online.

const app= initializeApp( {
    projectId,
    apiKey: "none",
    authDomain: "no.such.com"   // tbd. is this needed?
} );
...

useFirestoreEmulator(firestore, 'localhost',FIRESTORE_PORT);
useFunctionsEmulator(fns, 'localhost',FUNCTIONS_PORT);
useAuthEmulator(auth, AUTH_URL);

...
await signInWithCustomToken( auth, JSON.stringify({ uid: "dev" }) );   // GETS STUCK!!

The promise never resolves. No console output, no error.

firebase-tools 9.5.0
firebase 0.900.15

[yuchenshi]

Weird, I just tried this and it signed me in correctly. It's also weird that you're not seeing any console output. Would you mind looking into the Network tab in your DevTools and see what request it is sending? Pay special attention to the signin request and see which host and port it is sending the request to. Also, which browser are you using and what's the format for AUTH_URL?

[akauppi]

Here are the fetches in the networks tab:

One OPTIONS to accounts:signInWithCustomToken?..., followed by a POST that has a good JWT response.

One OPTIONS to accounts:lookup?key=none, followed by a POST to same address. Great payload.

I've configured the auth port to 9100 - but that's not the cause (tried with default 9099, too).

Browser: Chrome 88 (Safari behaved the same)
macOS 11.2

AUTH_URL is "http://localhost:9100"

---

If you wish to try to reproduce:

$ git clone git@github.com:akauppi/GroundLevel-es-firebase.git
$ cd GroundLevel*
$ git checkout recamp-firebase-9x
$ npm install
$ cd packages/app
$ npm run dev

Open http://localhost:3000?user=dev

[yuchenshi]

Thanks! We're aware of an issue that may cause the new SDK to get stuck on initialization and we're looking into fixes. Thanks again for bringing this to our attention and please stay tuned -- a quick fix may be coming.

[sam-gc]

This issue should be fixed in the next release (#4550)

Edit: although this issue will still crop up in Safari, as Safari initializes the iframe early; we also need to update the emulator code, which is in the works

[akauppi]

I confirm that signInWithCustomToken works in 0.900.16 (Chrome). It also seems to work for me in Safari (14.0.3)