Google Cloud Functions - Client Call Error (Android Studio) :FirebaseFunctionsException: Response is not valid JSON object

Question

cannot execute Google Cloud Functions Android Client Call.

I create Cloud Function from cloud console, and test works on cloud console.

but on Android client app, it's not work.

so, i did import Google Cloud Service Quick Start Project on my android studio, same error too.

this is quick start project url.

https://cloud.google.com/functions/docs/quickstart-console

this is my code.

Google Cloud Functions Call Class

public class TestClass {

private FirebaseFunctions mFunctions;

public TestClass(){
    mFunctions=new FirebaseFunctions();
}
..

public Task<String> myFunc(String text) {
    // Create the arguments to the callable function, which is just one string
    Map<String, Object> data = new HashMap<>();
    data.put("message", text);

    return mFunctions
            .getHttpsCallable("myFunc")
            .call(data)
            .continueWith(new Continuation<HttpsCallableResult, String>() {
                @Override
                public String then(@NonNull Task<HttpsCallableResult> task) throws Exception {
                    // This continuation runs on either success or failure, but if the task
                    // has failed then getResult() will throw an Exception which will be
                    // propagated down.
                    String result = (String) task.getResult().getData();
                    Log.d("gcf",result);
                    return result;
                }
            });
}

}

in MainActivity Execute Method

button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            TestClass testClass=new TestClass();

            testClass.myFunc("im bhw")
                    .addOnCompleteListener(new OnCompleteListener<String>() {
                        @Override
                        public void onComplete(@NonNull Task<String> task) {
                            if (!task.isSuccessful()) {
                                Exception e = task.getException();
                                if (e instanceof FirebaseFunctionsException) {
                                    FirebaseFunctionsException ffe = (FirebaseFunctionsException) e;
                                    FirebaseFunctionsException.Code code = ffe.getCode();
                                    Object details = ffe.getDetails();
                                }

                                // [START_EXCLUDE]
                                Log.w("gcf", "myFunc:onFailure", e);
                                Toast.makeText(getApplicationContext(),"An error occurred.",Toast.LENGTH_SHORT).show();
                                return;
                                // [END_EXCLUDE]
                            }

                            // [START_EXCLUDE]
                            String result = task.getResult();
                            Toast.makeText(getApplicationContext(),result,Toast.LENGTH_SHORT).show();

                            // [END_EXCLUDE]
                        }
                    });
        }
    });

Google Cloud Function

exports.myFunc = (req, res) => {
    if (req.body.message === undefined) {
        res.status(400).send('No message defined!');
    } 
    else {
        console.log(req.body.message);
        res.status(200).send('Success: ' + req.body.message);
    }
};
exports.myFunc = (req, res) => {
    if (req.body.message === undefined) {
    res.status(400).send('No message defined!');
    }
    else {
        console.log(req.body.message);
        res.status(200).send('Success: ' + req.body.message);
    }
};

result

com.google.firebase.functions.FirebaseFunctionsException: Response is not valid JSON object.
    at com.google.firebase.functions.FirebaseFunctions$4.onResponse(SourceFile:296)
    at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:177)
    at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
    at java.lang.Thread.run(Thread.java:761)
 Caused by: org.json.JSONException: Value <!DOCTYPE of type java.lang.String cannot be converted to JSONObject
    at org.json.JSON.typeMismatch(JSON.java:111)
    at org.json.JSONObject.<init>(JSONObject.java:160)
    at org.json.JSONObject.<init>(JSONObject.java:173)
    at com.google.firebase.functions.FirebaseFunctions$4.onResponse(SourceFile:294)
    at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:177) 
    at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
    at java.lang.Thread.run(Thread.java:761) com.google.firebase.functions.FirebaseFunctionsException: Response is not valid JSON object.
    at com.google.firebase.functions.FirebaseFunctions$4.onResponse(SourceFile:296)
    at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:177)
    at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
    at java.lang.Thread.run(Thread.java:761)
 Caused by: org.json.JSONException: Value <!DOCTYPE of type java.lang.String cannot be converted to JSONObject
    at org.json.JSON.typeMismatch(JSON.java:111)
    at org.json.JSONObject.<init>(JSONObject.java:160)
    at org.json.JSONObject.<init>(JSONObject.java:173)
    at com.google.firebase.functions.FirebaseFunctions$4.onResponse(SourceFile:294)
    at com.squareup.okhttp.Call$AsyncCall.execute(Call.java:177) 
    at com.squareup.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
    at java.lang.Thread.run(Thread.java:761) 

all code reffered by Firebase offical site https://firebase.google.com/docs/functions/callable?authuser=0

on Cloud Console DashBoard , API Traffics catchs

what is matter?

Answer 1

Response at a minimum must include a JSON object with data or error values.

If you modify your function to be:

exports.myFunc = (req, res) => {
    if (req.body.message === undefined) {
        res.status(400).send({error: 'No message defined!'});
    } 
    else {
        console.log(req.body.message);
        res.status(200).send({data: 'Success: ' + req.body.message});
    }
};
exports.myFunc = (req, res) => {
    if (req.body.message === undefined) {
    res.status(400).send({error: 'No message defined!'});
    }
    else {
        console.log(req.body.message);
        res.status(200).send({data: req.body.message});
    }
};

You should be ok.

check https://firebase.google.com/docs/functions/callable-reference