java – Can't Disable Offline Data In Firestore-ThrowExceptions

Exception or error:

After deleting data from my Firestore Database, it takes my Android app some time to realize that the data was deleted, and I assume that it’s happening due the auto data cache. My app has nothing to do with offline usage and I’d like to disable this feature…

I have added this in my custom Application Class:

import android.app.Application;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.FirebaseFirestoreSettings;

public class ApplicationClass extends Application {

    @Override
    public void onCreate() {
        super.onCreate();

        FirebaseFirestore db=FirebaseFirestore.getInstance();
        FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
                .setPersistenceEnabled(false)
                .build();
        db.setFirestoreSettings(settings);
    }
}

The problem occurs after turning off the internet connection and than turning it back on (while the app is still running, in the background or not)- the Firestore module seems to lose connection to the server, and it makes the opposite operation than the intended one – instead of stop taking data from the cache, it takes data from the cache only.

For example, debugging this code will always show that isFromCache is true and documentSnapshot is empty (even though that on the server side – it’s not empty):

usersRef.document(loggedEmail).collection("challenges_received").get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
    @Override
    public void onSuccess(QuerySnapshot documentSnapshots) {
        boolean isFromCache=documentSnapshots.getMetadata().isFromCache();
        if (!documentSnapshots.isEmpty()) {
        }
    }
});

Is this normal behavior?

Is there another way to disable the data cache in Cloud Firestore?


EDIT:

Adding: FirebaseFirestore.setLoggingEnabled(flase); (instead of the code above) in the custom Application Class gives the same result.

How to solve:

According to Cloud Firestore 16.0.0 SDK update, there is now a solution to this problem:

enter image description here


You are now able to choose if you would like to fetch your data from the server only, or from the cache only, like this (an example for server only):

DocumentReference documentReference= FirebaseFirestore.getInstance().document("example");
documentReference.get(Source.SERVER).addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
    @Override
    public void onSuccess(DocumentSnapshot documentSnapshot) {
            //...
    }
});

For cache only, just change the code above to Source.CACHE.


By default, both methods still attempt server and fall back to the cache.

###

I just ran a few tests in an Android application to see how this works. Because Firestore is currently still in beta release and the product might suffer changes any time, i cannot guarantee that this behaviour will still hold in the future.

db.collection("tests").document("fOpCiqmUjAzjnZimjd5c").get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        DocumentSnapshot documentSnapshot = task.getResult();
        System.out.println("isFromCache: " + documentSnapshot.getMetadata().isFromCache());
    }
});

Regarding the code, is the same no matter if we’re getting the data from the cache or you are connected to the servers.

When I’m online it prints:

isFromCache: false

When I’m offline, it prints:

isFromCache: true

So, for the moment, there is no way to stop the retrieval of the data from the cache while you are not connected to the server, as you cannot force the retrieval of the data from the cache while you’re connected to the server.

If instead I use a listener:

db.collection("tests").document("fOpCiqmUjAzjnZimjd5c").addSnapshotListener(new DocumentListenOptions().includeMetadataChanges(), new EventListener<DocumentSnapshot>() {
    @Override
    public void onEvent(DocumentSnapshot documentSnapshot, FirebaseFirestoreException e) {
        System.out.println("listener.isFromCache: " + documentSnapshot.getMetadata().isFromCache());
    }
});

I get two prints when I’m online:

listener.isFromCache: true
listener.isFromCache: false

Firestore is desinged to retrieve data from the chache when the device is permanently offline or while your application temporarily loses its network connection and for the moment you cannot change this behaviour.

As a concusion, an API that does something like this, currently doesn’t exist yet.

Edit: Unlike in Firebase, where to enable the offline persistence you need use this line of code:

FirebaseDatabase.getInstance().setPersistenceEnabled(true);

In Firestore, for Android and iOS, offline persistence is enabled by default.

Using the above line of code, means that you tell Firebase to create a local (internal) copy of your database so that your app can work even if it temporarily loses its network connection.

In Firestore we find the opposite, to disable persistence, we need to set the PersistenceEnabled option to false. This means that you tell Firestore not to create a local copy of your database on user device, which in term means that you’ll not be able to query your database unless your are connected to Firebase servers. So without having a local copy of your database and if beeing disconected, an Exception will be thrown. That’s why is a good practice to use the OnFailureListener.

Update (2018-06-13): As also @TalBarda mentioned in his answer this is now possible starting with the 16.0.0 SDK version update. So we can achieve this with the help of the DocumentReference.get(Source source) and Query.get(Source source) methods.

By default, get() attempts to provide up-to-date data when possible by waiting for data from the server, but it may return cached data or fail if you are offline and the server cannot be reached. This behavior can be altered via the Source parameter.

So we can now pass as an argument to the DocumentReference or to the Query the source so we can force the retrieval of data from the server only, chache only or attempt server and fall back to the cache.

So something like this is now possible:

FirebaseFirestore db = FirebaseFirestore.getInstance();
DocumentReference docIdRef = db.collection("tests").document("fOpCiqmUjAzjnZimjd5c");
docIdRef.get(Source.SERVER).addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
    @Override
    public void onSuccess(DocumentSnapshot documentSnapshot) {
        //Get data from the documentSnapshot object
    }
});

In this case, we force the data to be retrieved from the server only. If you want to force the data to be retrieved from the cache only, you should pass as an argument to the get() method, Source.CACHE. More informations here.

###

FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
.setPersistenceEnabled(false)
.build();
dbEventHome.setFirestoreSettings(settings);

By setting this it is fetching from server always.

###

// Enable Firestore logging
    FirebaseFirestore.setLoggingEnabled(flase);
// Firestore
    mFirestore = FirebaseFirestore.getInstance();

In general: the Firebase client tries to minimize the number of times it downloads data. But it also tries to minimize the amount of memory/disk space it uses.

The exact behavior depends on many things, such as whether the another listener has remained active on that location and whether you’re using disk persistence. If you have two listeners for the same (or overlapping) data, updates will only be downloaded once. But if you remove the last listener for a location, the data for that location is removed from the (memory and/or disk) cache.

Without seeing a complete piece of code, it’s hard to tell what will happen in your case.

Alternatively: you can check for yourself by enabling Firebase’s logging [Firebase setLoggingEnabled:YES];

try this For FireBase DataBase

  mDatabase.getReference().keepSynced(false);      
      FirebaseDatabase.getInstance().setPersistenceEnabled(false);

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