Getting “INTERNAL” exception when an async Firebase function is called from android app

Question

I’m trying to call an async Firebase function from android app and getting “INTERNAL” exception when the function returns.

Android:

 private Task<String> fetchData() {
    // Create the arguments to the callable function, which is just one string
    Map<String, Object> data = new HashMap<>();
    data.put(“id”, “abc”);

    return FirebaseFunctions.getInstance()
            .getHttpsCallable(“calculate”)
            .call(data)
            .continueWith(new Continuation<HttpsCallableResult, String>() {
                @Override
                public String then(@NonNull Task<HttpsCallableResult> task) throws Exception {
                    Map<String, Object> result = (Map<String, Object>) task.getResult().getData();
                    return (String)result.get(“data”);
                }
            });
 }

Firebase Function:

exports.calculate = functions.https.onCall((data, context) => {
    const text = data.id;
    return calc.calculate( (err, response) => {
        if(err) {
            // handle error
        } else {
            const data = response.dataValue;
        }
     }).then(() => {
        return {“data”: data};
     });
});

Exception:

com.google.firebase.functions.FirebaseFunctionsException: INTERNAL

Answer 1

The documentation for handling errors in callable functions indicates that an instance of functions.https.HttpsError must be returned:

To ensure the client gets useful error details, return errors from a callable by throwing (or returning a Promise rejected with) an instance of functions.https.HttpsError... If an error other than HttpsError is thrown from your functions, your client instead receives an error with the message INTERNAL and the code internal.

It seems likely that your calc.calculate() call is returning an error that is not being handled correctly, resulting in a returned error status of INTERNAL.

Following the example in the document linked above, your code should be something like:

if(err) {
    // handle error
    throw new functions.https.HttpsError('calc-error', 'some error message');
} else {
    const data = response.dataValue;
}