Partition-Based Sync - React Native SDK

Partition Value

When you select Partition-Based Sync for your backend App configuration, your client implementation must include a partition value. This is the value of the partition key field you select when you configure Partition-Based Sync.

The partition value determines which data the client application can access.

You pass in the partition value when you open a synced realm.

Configure a Partition-Based Sync Realm

To open a Flexible Sync realm, use @realm/react's createRealmContext() function and its returned RealmProvider.

In a RealmProvider that's nested in a UserProvider, add a sync property with a SyncConfiguration object that contains flexible: true.

Note that UserProvider automatically passes an authenticated user to RealmProvider.

<RealmProvider
  schema={[YourObjectModel]}
  sync={{
    partitionValue: 'testPartition',
  }}>
  <RestOfApp />
</RealmProvider>

Copy Data and Open a New Realm

To copy data from an existing realm to a new realm with different configuration options, pass the new configuration the Realm.writeCopyTo() method.

In the new realm's configuration, you must specify the path.

If you write the copied realm to a realm file that already exists, the data is written object by object. The copy operation replaces objects if there already exists objects for given primary keys. The schemas of the realm you copy and the realm you are writing to must be compatible for the copy operation to succeed. Only objects in the schemas of both configurations are copied over.

The configuration change can include modifications to SyncConfiguration:

• Local realm to synced realm

• Synced Realm to local realm

The configuration change can also include changes to encryptionKey property of the Configuration:

• Encrypted realm to unencrypted realm

• Unencrypted realm to encrypted realm

const localConfig = {
  schema: [Car],
  path: "localOnly.realm",
};
const localRealm = await Realm.open(localConfig);
const syncedConfig = {
  schema: [Car],
  path: "copyLocalToSynced.realm",
  sync: {
    user: app.currentUser,
    partitionValue: "myPartition",
  },
};
localRealm.writeCopyTo(syncedConfig);
const syncedRealm = await Realm.open(syncedConfig);

const localConfig: Realm.Configuration = {
  schema: [Car],
  path: "localOnly.realm",
};
const localRealm = await Realm.open(localConfig);
const syncedConfig: Realm.Configuration = {
  schema: [Car],
  path: "copyLocalToSynced.realm",
  sync: {
    user: app.currentUser!,
    partitionValue: "myPartition",
  },
};
localRealm.writeCopyTo(syncedConfig);
const syncedRealm = await Realm.open(syncedConfig);

You can also combine changes to configuration. For example, you can open a local encrypted realm as a synced unencrypted realm or a unencrypted synced realm as an encrypted synced realm.

// Create a secure key.
const encryptionKey = new Int8Array(64);
// ... store key
const syncedEncryptedConfig = {
  schema: [Car],
  path: "syncedEncrypted.realm",
  sync: {
    user: app.currentUser,
    partitionValue: "myPartition",
  },
  encryptionKey,
};
const syncedEncryptedRealm = await Realm.open(syncedEncryptedConfig);
const localUnencryptedConfig = {
  schema: [Car],
  path: "copyLocalUnencrypted.realm",
};
syncedEncryptedRealm.writeCopyTo(localUnencryptedConfig);
const localUnencryptedRealm = await Realm.open(syncedEncryptedConfig);

// Create a secure key.
const encryptionKey = new Int8Array(64);
// ... store key
const syncedEncryptedConfig: Realm.Configuration = {
  schema: [Car],
  path: "syncedEncrypted.realm",
  sync: {
    user: app.currentUser!,
    partitionValue: "myPartition",
  },
  encryptionKey,
};
const syncedEncryptedRealm = await Realm.open(syncedEncryptedConfig);
const localUnencryptedConfig: Realm.Configuration = {
  schema: [Car],
  path: "copyLocalUnencrypted.realm",
};
syncedEncryptedRealm.writeCopyTo(localUnencryptedConfig);
const localUnencryptedRealm = await Realm.open(syncedEncryptedConfig);

Migrate from Partition-Based Sync to Flexible Sync

You can migrate your App Services Device Sync Mode from Partition-Based Sync to Flexible Sync. Migrating is an automatic process that does not require any changes to your application code. Automatic migration requires Realm Node.js SDK version 11.10.0 or newer.

Migrating enables you to keep your existing App Services users and authentication configuration. Flexible Sync provides more versatile permissions configuration options and more granular data synchronization.

For more information about how to migrate your App Services App from Partition-Based Sync to Flexible Sync, refer to Migrate Device Sync Modes.