Offline persistance between app restarts

[VLNTNA]

Hello,

I have the following problem:

• At first I request data like so: firestack.database.ref().child('projects').on('value', callback)
• Then I go offline and close the app completely
• When I restart the app and still offline, the same request is executed - according to the Firebase docs, it should be possible to query that data locally because it has already been previously loaded when online.

How can I implement this behaviour with your library ?

[chaitanya-bhagavan]

Try this.

const firestack = new Firestack(FIREBASE_CONFIG); let firestackDb; firestack.onReady(()=> { firestackDb = firestack.database; firestackDb.setPersistence(true); });

Disable the network and restart the app and all your queries should work just fine.

[VLNTNA]

Thanks for your response ! I already set persistence to true, like you suggested.

Database operations that I execute offline, are successfully sent to Firebase when re-establishing connection. For example, it works when I add new data offline.

But when starting the app, I initially have to load all data that is stored at a specific path in Firebase with .on('value'). So when I try to load this data and I am offline, i don't get any data, although I have previously queried the same data when online.

The Firebase docs say:

The Firebase Realtime Database stores data returned from a query for use when offline. For queries constructed while offline, the Firebase Realtime Database continues to work for previously loaded data. If the requested data hasn't loaded, the Firebase Realtime Database loads data from the local cache.

Is this already possible w/ Firestack ?

[auser]

Yes. It's embedded with the RN SDK, so it's possible. I believe it's actually already implemented, but I'll have to look specifically. I can check this out tonight in more depth.

[VLNTNA]

Thank you - would be awesome ! :)

[chaitanya-bhagavan]

There is a bug in the code due to which persistence is never enabled. I have created a pull request for a fix.

[VLNTNA]

Thank you for the fix - it's now working with one exception:

When starting the app for the first time, it works.
When reloading the app, following error occurs ( after setting database references with .ref() ):

Debug logs:

[chaitanya-bhagavan]

I also get the same exception on a reload. This is because the JS code
calls database.setPersistence on an existing FirebaseApp that is being
reused. For the time-being click on dismiss and you should be able to go
back to the running app.

On Mon, Oct 31, 2016 at 8:41 PM, Valentina Pegler notifications@github.com
wrote:

Thank you for the fix - it's now working with one exception:

When starting the app for the first time, it works.
When reloading the app, following error occurs ( after setting database
references with .ref() ):

[image: screen shot 2016-10-31 at 14 36 28]
https://cloud.githubusercontent.com/assets/8790113/19855930/6e38d28c-9f77-11e6-834e-6d6465da0007.png

Debug logs:

[image: persistence_error]
https://cloud.githubusercontent.com/assets/8790113/19858745/f94a2190-9f82-11e6-9b0d-83cf65667583.jpg

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Regards,

Chaitanya Bhagvan

[chaitanya-bhagavan]

Created one more PR to fix this exception.

[smhatre59]

The issue still exists
Here is my code:
At the beginning index.android.js:

const firestack = new Firestack(configurationOptions);
let firestackDb;
firestack.onReady(()=> {
                          firestackDb = firestack.database;
                          firestackDb.setPersistence(true);
                        });

I then pass firestackDb as a prop in Navigator inside render method:

<Navigator
          initialRoute={{component: this.state.openingPage}}
          configureScene={() => {
            return Navigator.SceneConfigs.HorizontalSwipeJumpFromLeft;
          }}
          renderScene={(route, navigator) => {
            if(route.component){
              // Pass the navigator the the page so it can navigate as well.
              // Pass firebaseApp so it can make calls to firebase.
              return React.createElement(route.component, { navigator,  firestack,firestackDb});
            }
        }} />

Then use the prop in following manner in a component:

this.tasksRef = this.props.firestack.dataabase.ref();
 or  
this.tasksRef = this.props.firestackDb.ref();

[smhatre59]

I am not sure if this is the right way but the offline persistence works correctly if I setpersistence in getDatabaseRef method around line 215 in FirestackDatabase.java file as follows:

public DatabaseReference getDatabaseRef() {
    FirebaseDatabase.getInstance().setPersistenceEnabled(true);
    return FirebaseDatabase.getInstance().getReference(mPath);
  }

I was able to save data locally after this without the error:
With network the app has following data fetched from database:

Once I kill the app,switch off the wifi and restart the app the todo items stay on screen.
Here is stackoverflow link which I used for finding the fix:
http://stackoverflow.com/questions/37753991/com-google-firebase-database-databaseexception-calls-to-setpersistenceenabled/37766261#37766261

I am guessing that enablePersistence method as written on line 306 called persistenceenabled before :

public void enablePersistence(
    final Boolean enable,
    final Callback callback) {
      //try {
      //   FirebaseDatabase.getInstance()
      //     .setPersistenceEnabled(enable);
      // } catch (Throwable t) {
        // Log.e(TAG, "FirebaseDatabase setPersistenceEnabled exception", t);
      // }

      WritableMap res = Arguments.createMap();
      res.putString("status", "success");
      callback.invoke(null, res);
  }

But the call goes to it after creation of database instance.
Kindly suggest a better way to fix this issue or request a PR if you need it.

[chaitanya-bhagavan]

@smhatre59 This is what I am doing in my code

export let firestackDb;
firestack.onReady((props) => {
  console.log('Firestack ready');
  firestack.database.setPersistence(true)
    .then( () => {
      console.log('Persistence enabled');
      firestackDb = firestack.database;
    });
});

Also, you should call Navigator after setPersistence is resolved

[smhatre59]

I am currently calling navigator directly in the render method:

render() {
    if (this.state.openingPage) {
      return (
        // Take the user to whatever page we set the state to.
        // We will use a transition where the new page will slide in from the Left.
        <Navigator
          initialRoute={{component: this.state.openingPage}}
          configureScene={() => {
            return Navigator.SceneConfigs.HorizontalSwipeJumpFromLeft;
          }}
          renderScene={(route, navigator) => {
            if(route.component){
              // Pass the navigator the the page so it can navigate as well.
              // Pass firebaseApp so it can make calls to firebase.
              return React.createElement(route.component, { navigator,  firestack});
            }
        }} />
      );
    } else {
      return (
        // Our default loading view while waiting to hear back from firebase
        <View style={styles.container}>
          <ToolbarAndroid title="Login" />
          <View style={styles.body}>
            <ActivityIndicator size="large" />
          </View>
        </View>
      );
}
  }

Can you please explain how to give a call to navigator after setPersistence in enabled?

[chaitanya-bhagavan]

I think you should create a firestack instance and setPersistence in index.js. Once the firestack promise is resolved you can call registerComponent

…

On 29-Nov-2016 11:34 PM, "Saurabh Mhatre" ***@***.***> wrote: I am currently navigator directly in the render method: render() { if (this.state.openingPage) { return ( // Take the user to whatever page we set the state to. // We will use a transition where the new page will slide in from the Left. <Navigator initialRoute={{component: this.state.openingPage}} configureScene={() => { return Navigator.SceneConfigs.HorizontalSwipeJumpFromLeft; }} renderScene={(route, navigator) => { if(route.component){ // Pass the navigator the the page so it can navigate as well. // Pass firebaseApp so it can make calls to firebase. return React.createElement(route.component, { navigator, firestack}); } }} /> ); } else { return ( // Our default loading view while waiting to hear back from firebase <View style={styles.container}> <ToolbarAndroid title="Login" /> <View style={styles.body}> <ActivityIndicator size="large" /> </View> </View> ); } } Can you please explain how to give a call to navigator after setPersistence in enabled? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#96 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEkuVZoKlxR4f5SwGBDK7W4YvAAkUF5Yks5rDGk9gaJpZM4KkI__> .

[srinivasGit]

PLEASE HELP!

@VLNTNA @chaitanya0bhagvan

Database operations that I execute offline, are successfully sent to Firebase when re-establishing connection. For example, it works when I add new data offline.

But when starting the app, I initially have to load all data that is stored at a specific path in Firebase with .on('value'). So when I try to load this data and I am offline, i don't get any data, although I have previously queried the same data when online.