# Make Data Persist in Liberator

When a StreamLink application publishes data to Liberator, the data does not normally persist within Liberator if the connection to the Liberator is lost. You can use the `persistent` configuration attribute to ensure that the data does persist across reconnections. When `persistent` is set to true, if the application reconnects to the Liberator (or to a different Liberator, depending on the failover configuration), StreamLink automatically resends the data. Let’s look at an example of this in action:

## 1. Change end-user mode

Let’s say that the Liberator has an object `/MyMode` representing a mode that the end-user is in, and the default mode of this object is "A". When StreamLink logs an end-user in to Liberator, the mode starts off as "A". To change the end-user to mode "B", send the following publish command:

```js
myCommandListener = new MyCommandListener();
fields = {"mode": "B"};
streamLink.publishToSubject("/MyMode", fields, myCommandListener);
```

## 2. Specify persistent configuration

If the end-user is disconnected from the Liberator, the user session is lost. With the coding in the previous step, when StreamLink reconnects, the end-user’s mode will have defaulted back to mode "A". If you want the mode to be automatically set to "B" again when StreamLink reconnects, specify the persistent configuration attribute as true:

```js
myCommandListener = new MyCommandListener();
fields = {"mode": "B"};
myCommandParameters = {"persistent": true}
streamLink.publishToSubject("/MyMode",
    fields,
    myCommandListener,
    myCommandParameters);
```

This code ensures that the object `/MyMode` with field "mode=B" is reliably sent to the Liberator whenever a reconnect occurs.

## 3. Remove persistent configuration

Let’s say that you subsequently no longer want the `/MyMode` state to persist in mode "B", simply remove the persistence, as follows:

```js
myCommandListener = new MyCommandListener();
fields = {"mode": "B"};
myCommandParameters = {"persistent": true}

myCommandSubscription = streamLink.publishToSubject("/MyMode",
    fields,
    myCommandListener,
    myCommandParameters);
...
/* Some time later, myMode no longer needs to be persisted...*/

myCommandSubscription.unPersist();
```

Note that after the call to `unPersist()`, `/MyMode` remains in mode "B" until such time as StreamLink reconnects to the Liberator.