Callable Cloud Function error: Response is missing data field

Question

Don't know how to get responce from cloud function in flutter.

My cloud function

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();

exports.testDemo = functions.https.onRequest((request, response) => {
  return response.status(200).json({msg:"Hello from Firebase!"});
 });

My flutter code

///Getting an instance of the callable function:
    try {
      final HttpsCallable callable = CloudFunctions.instance.getHttpsCallable(
        functionName: 'testDemo',);

      ///Calling the function with parameters:
      dynamic resp = await callable.call();
      print("this is responce from firebase $resp");

    } on CloudFunctionsException catch (e) {
      print('caught firebase functions exception');
      print(e.code);
      print(e.message);
      print(e.details);
    } catch (e) {
      print('caught generic exception');
      print(e);
    }

flutter: caught firebase functions exception flutter: INTERNAL flutter: Response is missing data field. flutter: null

Answer 1

Use

exports.testDemo = functions.https.onCall((data, context) => {
  return {msg:"Hello from Firebase!"};
});

in cloud functions. Callable is different than Request

When you call the functions you need to add the parameters:

change:

 // Calling a function without parameters is a different function!
  dynamic resp = await callable.call();

to:

dynamic resp = await callable.call(
     <String, dynamic>{
       'YOUR_PARAMETER_NAME': 'YOUR_PARAMETER_VALUE',
     },
);

as described here

then to print the response:

print(resp.data)
print(resp.data['msg'])

The Firebase Functions for flutter example here and here