Firebase callable + express?

Question

With functions.https.onRequest(app); it was possible to use express right away.

I'm wondering if it's possible to use functions.https.onCall(...) together with express in the same way?

onCall(...) seem to have a different signature but maybe there is still a way to keep using express while working with onCall(...) functions?

Answer 1

No, it's not possible. Callable functions force your endpoint to use a certain path, a certain type of input (JSON via POST) and a certain type of output (also JSON). Express wouldn't really help you out, given the constraints of how callables work. You can read about all the callable protocol details in the documentation. You can see that callables abstract away all of the details of the request and response, which you would normally work with when using Express.