DataSyncEntity SDK entity

The DataSyncEntity SDK entity is a local client-side handle that subscribes to the real-time updates of a DataSync entity. It is the subscribe-side counterpart to the pubnub.dataSync.* read and write methods, and subscription() is the only API it exposes.

SDK entity is not the same as a DataSync entity

An SDK entity is a local client-side handle. A DataSync entity is a stored server-side record, the source of truth for your application state, managed through the DataSync API. Creating DataSyncEntity performs no network call and does not require a matching server-side record to exist.

Create a DataSyncEntity

Use this factory method to return a local DataSyncEntity SDK entity for a single DataSync entity.

1pubnub.dataSyncEntity(id: String): DataSyncEntity

* required

Parameter	Description
id * Type: String	Identifier of the DataSync entity to create a subscription of.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

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Available operations

Operation	Description
subscription(options)	Returns a local subscription object for the DataSync entity's own data channel, id. The subscription delivers only the events that arrive on that channel.
subscription(projection, options)	Returns a subscription for a DataSync projection of the DataSync entity. Pass default or __default__ to observe the entity itself, the same as the first method. Any other name observes the projection on its own __{projection}__{id} channel. A blank name throws an IllegalArgumentException.

Both methods accept the usual SubscriptionOptions. The projection is chosen per subscription rather than per SDK entity, so one SDK entity can serve several projections at once. Each subscription is subscribed and unsubscribed independently. To receive the events, attach a dataSync listener, as described in Add DataSync listener.

Subscribing needs a channel read grant

A DataSync SDK entity subscribes to an ordinary channel, so an authorized client needs a read grant on that channel. The grants from DataSyncGrant.user, DataSyncGrant.channel, and DataSyncGrant.entity cover only the DataSync API methods, not subscribing. Use DataSyncGrant.subscribe or DataSyncGrant.subscribePattern to grant the subscribe. Refer to Grant token.

Relationship and membership changes are not delivered on their own id

A relationship change is delivered on the data channels of the two entities it links (entityAId and entityBId), and a membership change on those of its userId and channelId. It is never published on a channel named after the relationship or membership id, so the Kotlin SDK has no SDK entity for either. To watch memberships appear and disappear, observe the linked user and channel with DataSyncUser and DataSyncChannel instead. Refer to Where each event is delivered.

Observe a projection

A projection channel carries only the fields the named projection exposes. The code below subscribes to the admin projection of a DataSync entity.

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