PowerSyncBackendConnector.ts

import { PowerSyncCredentials } from './PowerSyncCredentials.js';
import type { AbstractPowerSyncDatabase } from '../AbstractPowerSyncDatabase.js';

export interface PowerSyncBackendConnector {
  /** Allows the PowerSync client to retrieve an authentication token from your backend
   * which is used to authenticate against the PowerSync service.
   *
   * This should always fetch a fresh set of credentials - don't use cached
   * values.
   *
   * Return null if the user is not signed in. Throw an error if credentials
   * cannot be fetched due to a network error or other temporary error.
   *
   * This token is kept for the duration of a sync connection.
   */
  fetchCredentials: () => Promise<PowerSyncCredentials | null>;

  /** Upload local changes to the app backend.
   *
   * Use {@link AbstractPowerSyncDatabase.getCrudBatch} to get a batch of changes to upload.
   *
   * Any thrown errors will result in a retry after the configured wait period (default: 5 seconds).
   */
  uploadData: (database: AbstractPowerSyncDatabase) => Promise<void>;
}