wallet-core: implement exporting DB to file

12 files changed, 176 insertions, 71 deletions

diff --git a/packages/idb-bridge/src/SqliteBackend.ts b/packages/idb-bridge/src/SqliteBackend.ts
index 26ed43b0f..8213de366 100644
--- a/packages/idb-bridge/src/SqliteBackend.ts
+++ b/packages/idb-bridge/src/SqliteBackend.ts
@@ -44,15 +44,15 @@ import {
   structuredEncapsulate,
   structuredRevive,
 } from "./index.js";
-import { ConstraintError, DataError } from "./util/errors.js";
-import { getIndexKeys } from "./util/getIndexKeys.js";
-import { deserializeKey, serializeKey } from "./util/key-storage.js";
-import { makeStoreKeyValue } from "./util/makeStoreKeyValue.js";
 import {
   Sqlite3Database,
   Sqlite3Interface,
   Sqlite3Statement,
 } from "./sqlite3-interface.js";
+import { ConstraintError, DataError } from "./util/errors.js";
+import { getIndexKeys } from "./util/getIndexKeys.js";
+import { deserializeKey, serializeKey } from "./util/key-storage.js";
+import { makeStoreKeyValue } from "./util/makeStoreKeyValue.js";
 
 function assertDbInvariant(b: boolean): asserts b {
   if (!b) {
@@ -1927,6 +1927,13 @@ export class SqliteBackend implements Backend {
       });
     }
   }
+
+  async backupToFile(path: string): Promise<void> {
+    const stmt = this._prep("VACUUM INTO $filename;");
+    stmt.run({
+      filename: path,
+    });
+  }
 }
 
 const schemaSql = `
diff --git a/packages/taler-harness/src/bench1.ts b/packages/taler-harness/src/bench1.ts
index d260ea731..169e9150a 100644
--- a/packages/taler-harness/src/bench1.ts
+++ b/packages/taler-harness/src/bench1.ts
@@ -28,7 +28,6 @@ import {
   Logger,
 } from "@gnu-taler/taler-util";
 import {
-  AccessStats,
   createNativeWalletHost2,
   Wallet,
   WalletApiOperation,
@@ -66,7 +65,6 @@ export async function runBench1(configJson: any): Promise<void> {
   }
 
   let wallet = {} as Wallet;
-  let getDbStats: () => AccessStats;
 
   for (let i = 0; i < numIter; i++) {
     // Create a new wallet in each iteration
@@ -75,7 +73,11 @@ export async function runBench1(configJson: any): Promise<void> {
     if (i % restartWallet == 0) {
       if (Object.keys(wallet).length !== 0) {
         await wallet.client.call(WalletApiOperation.Shutdown, {});
-        console.log("wallet DB stats", j2s(getDbStats!()));
+        const stats = wallet.client.call(
+          WalletApiOperation.TestingGetDbStats,
+          {},
+        );
+        console.log("wallet DB stats", j2s(stats));
       }
 
       const res = await createNativeWalletHost2({
@@ -84,7 +86,6 @@ export async function runBench1(configJson: any): Promise<void> {
         httpLib: harnessHttpLib,
       });
       wallet = res.wallet;
-      getDbStats = res.getDbStats;
       await wallet.client.call(WalletApiOperation.InitWallet, {
         config: {
           testing: {
@@ -128,7 +129,8 @@ export async function runBench1(configJson: any): Promise<void> {
   }
 
   await wallet.client.call(WalletApiOperation.Shutdown, {});
-  console.log("wallet DB stats", j2s(getDbStats!()));
+  const stats = wallet.client.call(WalletApiOperation.TestingGetDbStats, {});
+  console.log("wallet DB stats", j2s(stats));
 }
 
 /**
diff --git a/packages/taler-harness/src/bench3.ts b/packages/taler-harness/src/bench3.ts
index ddf763c5b..e33b0c356 100644
--- a/packages/taler-harness/src/bench3.ts
+++ b/packages/taler-harness/src/bench3.ts
@@ -28,7 +28,6 @@ import {
 } from "@gnu-taler/taler-util";
 import { createPlatformHttpLib } from "@gnu-taler/taler-util/http";
 import {
-  AccessStats,
   createNativeWalletHost2,
   Wallet,
   WalletApiOperation,
@@ -77,7 +76,6 @@ export async function runBench3(configJson: any): Promise<void> {
     logger.info("not trusting exchange (validating signatures)");
   }
   let wallet = {} as Wallet;
-  let getDbStats: () => AccessStats;
 
   for (let i = 0; i < numIter; i++) {
     // Create a new wallet in each iteration
@@ -86,7 +84,11 @@ export async function runBench3(configJson: any): Promise<void> {
     if (i % restartWallet == 0) {
       if (Object.keys(wallet).length !== 0) {
         await wallet.client.call(WalletApiOperation.Shutdown, {});
-        console.log("wallet DB stats", j2s(getDbStats!()));
+        const stats = wallet.client.call(
+          WalletApiOperation.TestingGetDbStats,
+          {},
+        );
+        console.log("wallet DB stats", j2s(stats));
       }
 
       const res = await createNativeWalletHost2({
@@ -95,7 +97,6 @@ export async function runBench3(configJson: any): Promise<void> {
         httpLib: myHttpLib,
       });
       wallet = res.wallet;
-      getDbStats = res.getDbStats;
       await wallet.client.call(WalletApiOperation.InitWallet, {
         config: {
           features: {},
@@ -140,7 +141,8 @@ export async function runBench3(configJson: any): Promise<void> {
   }
 
   await wallet.client.call(WalletApiOperation.Shutdown, {});
-  console.log("wallet DB stats", j2s(getDbStats!()));
+  const stats = wallet.client.call(WalletApiOperation.TestingGetDbStats, {});
+  console.log("wallet DB stats", j2s(stats));
 }
 
 /**
diff --git a/packages/taler-util/src/types-taler-wallet.ts b/packages/taler-util/src/types-taler-wallet.ts
index 8a4de2b32..cbab53911 100644
--- a/packages/taler-util/src/types-taler-wallet.ts
+++ b/packages/taler-util/src/types-taler-wallet.ts
@@ -3582,3 +3582,31 @@ export const codecForStartExchangeWalletKycRequest =
       .property("exchangeBaseUrl", codecForString())
       .property("amount", codecForAmountString())
       .build("StartExchangeWalletKycRequest");
+
+export interface ExportDbToFileRequest {
+  /**
+   * Directory that the DB should be exported into.
+   */
+  directory: string;
+
+  /**
+   * Stem of the exported DB filename.
+   *
+   * The final name will be ${directory}/${stem}.${extension},
+   * where the extension depends on the used DB backend.
+   */
+  stem: string;
+}
+
+export const codecForExportDbToFileRequest = (): Codec<ExportDbToFileRequest> =>
+  buildCodecForObject<ExportDbToFileRequest>()
+    .property("directory", codecForString())
+    .property("stem", codecForString())
+    .build("ExportDbToFileRequest");
+
+export interface ExportDbToFileResponse {
+  /**
+   * Full path to the backup.
+   */
+  path: string;
+}
diff --git a/packages/taler-wallet-cli/src/index.ts b/packages/taler-wallet-cli/src/index.ts
index 73276c06c..e306f3225 100644
--- a/packages/taler-wallet-cli/src/index.ts
+++ b/packages/taler-wallet-cli/src/index.ts
@@ -249,7 +249,6 @@ export interface WalletContext {
 
 interface CreateWalletResult {
   wallet: Wallet;
-  getStats: () => AccessStats;
 }
 
 async function createLocalWallet(
@@ -275,7 +274,7 @@ async function createLocalWallet(
   });
 
   applyVerbose(walletCliArgs.wallet.verbose);
-  const res = { wallet: wh.wallet, getStats: wh.getDbStats };
+  const res = { wallet: wh.wallet };
 
   if (args.noInit) {
     return res;
@@ -379,7 +378,8 @@ async function withWallet<T>(
     await wh.wallet.client.call(WalletApiOperation.Shutdown, {});
     if (process.env.TALER_WALLET_DBSTATS) {
       console.log("database stats:");
-      console.log(j2s(wh.getStats()));
+      const stats = await wh.wallet.client.call(WalletApiOperation.TestingGetDbStats, {});
+      console.log(j2s(stats));
     }
     return result;
   }
diff --git a/packages/taler-wallet-core/src/host-impl.missing.ts b/packages/taler-wallet-core/src/host-impl.missing.ts
index 464a5af15..e03df2d8e 100644
--- a/packages/taler-wallet-core/src/host-impl.missing.ts
+++ b/packages/taler-wallet-core/src/host-impl.missing.ts
@@ -35,7 +35,6 @@ export async function createNativeWalletHost2(
   args: DefaultNodeWalletArgs = {},
 ): Promise<{
   wallet: Wallet;
-  getDbStats: () => AccessStats;
 }> {
   throw Error("not implemented");
 }
diff --git a/packages/taler-wallet-core/src/host-impl.node.ts b/packages/taler-wallet-core/src/host-impl.node.ts
index eb4191f81..7a6fc458e 100644
--- a/packages/taler-wallet-core/src/host-impl.node.ts
+++ b/packages/taler-wallet-core/src/host-impl.node.ts
@@ -22,10 +22,8 @@
 /**
  * Imports.
  */
-import type { IDBFactory } from "@gnu-taler/idb-bridge";
 // eslint-disable-next-line no-duplicate-imports
 import {
-  AccessStats,
   BridgeIDBFactory,
   MemoryBackend,
   createSqliteBackend,
@@ -46,18 +44,13 @@ import {
   getSqlite3FilenameFromStoragePath,
   makeTempfileId,
 } from "./host-common.js";
-import { Wallet } from "./wallet.js";
+import { Wallet, WalletDatabaseImplementation } from "./wallet.js";
 
 const logger = new Logger("host-impl.node.ts");
 
-interface MakeDbResult {
-  idbFactory: BridgeIDBFactory;
-  getStats: () => AccessStats;
-}
-
 async function makeFileDb(
   args: DefaultNodeWalletArgs = {},
-): Promise<MakeDbResult> {
+): Promise<WalletDatabaseImplementation> {
   const myBackend = new MemoryBackend();
   myBackend.enableTracing = false;
   const storagePath = args.persistentStoragePath;
@@ -106,12 +99,15 @@ async function makeFileDb(
   return {
     idbFactory: myBridgeIdbFactory,
     getStats: () => myBackend.accessStats,
+    exportToFile(directory, stem) {
+      throw Error("not supported");
+    },
   };
 }
 
 async function makeSqliteDb(
   args: DefaultNodeWalletArgs,
-): Promise<MakeDbResult> {
+): Promise<WalletDatabaseImplementation> {
   if (process.env.TALER_WALLET_DBTRACING) {
     BridgeIDBFactory.enableTracing = true;
   } else {
@@ -138,6 +134,13 @@ async function makeSqliteDb(
     getStats() {
       return myBackend.accessStats;
     },
+    async exportToFile(directory, stem) {
+      const path = `${directory}/${stem}.sqlite3`;
+      myBackend.backupToFile(path);
+      return {
+        path,
+      };
+    },
     idbFactory: myBridgeIdbFactory,
   };
 }
@@ -151,7 +154,6 @@ export async function createNativeWalletHost2(
   args: DefaultNodeWalletArgs = {},
 ): Promise<{
   wallet: Wallet;
-  getDbStats: () => AccessStats;
 }> {
   const myHttpFactory = (config: WalletRunConfig) => {
     let myHttpLib;
@@ -166,7 +168,7 @@ export async function createNativeWalletHost2(
     return myHttpLib;
   };
 
-  let dbResp: MakeDbResult;
+  let dbResp: WalletDatabaseImplementation;
 
   if (
     args.persistentStoragePath &&
@@ -179,8 +181,6 @@ export async function createNativeWalletHost2(
     dbResp = await makeSqliteDb(args);
   }
 
-  const myIdbFactory: IDBFactory = dbResp.idbFactory as any as IDBFactory;
-
   shimIndexedDB(dbResp.idbFactory);
 
   let workerFactory;
@@ -209,18 +209,12 @@ export async function createNativeWalletHost2(
 
   const timer = new SetTimeoutTimerAPI();
 
-  const w = await Wallet.create(
-    myIdbFactory,
-    myHttpFactory,
-    timer,
-    workerFactory,
-  );
+  const w = await Wallet.create(dbResp, myHttpFactory, timer, workerFactory);
 
   if (args.notifyHandler) {
     w.addNotificationListener(args.notifyHandler);
   }
   return {
     wallet: w,
-    getDbStats: dbResp.getStats,
   };
 }
diff --git a/packages/taler-wallet-core/src/host-impl.qtart.ts b/packages/taler-wallet-core/src/host-impl.qtart.ts
index b4ea04be5..8858087ab 100644
--- a/packages/taler-wallet-core/src/host-impl.qtart.ts
+++ b/packages/taler-wallet-core/src/host-impl.qtart.ts
@@ -23,7 +23,6 @@
  * Imports.
  */
 import type {
-  IDBFactory,
   ResultRow,
   Sqlite3Interface,
   Sqlite3Statement,
@@ -50,7 +49,7 @@ import {
   getSqlite3FilenameFromStoragePath,
   makeTempfileId,
 } from "./host-common.js";
-import { Wallet } from "./wallet.js";
+import { Wallet, WalletDatabaseImplementation } from "./wallet.js";
 
 const logger = new Logger("host-impl.qtart.ts");
 
@@ -103,7 +102,7 @@ export async function createQtartSqlite3Impl(): Promise<Sqlite3Interface> {
 
 async function makeSqliteDb(
   args: DefaultNodeWalletArgs,
-): Promise<MakeDbResult> {
+): Promise<WalletDatabaseImplementation> {
   BridgeIDBFactory.enableTracing = false;
   const filename = getSqlite3FilenameFromStoragePath(
     args.persistentStoragePath,
@@ -123,13 +122,20 @@ async function makeSqliteDb(
         primitiveStatements: numStmt,
       };
     },
+    async exportToFile(directory, stem) {
+      const path = `${directory}/${stem}.sqlite3`;
+      myBackend.backupToFile(path);
+      return {
+        path,
+      };
+    },
     idbFactory: myBridgeIdbFactory,
   };
 }
 
 async function makeFileDb(
   args: DefaultNodeWalletArgs = {},
-): Promise<MakeDbResult> {
+): Promise<WalletDatabaseImplementation> {
   BridgeIDBFactory.enableTracing = false;
   const myBackend = new MemoryBackend();
   myBackend.enableTracing = false;
@@ -165,6 +171,9 @@ async function makeFileDb(
   return {
     idbFactory: myBridgeIdbFactory,
     getStats: () => myBackend.accessStats,
+    exportToFile(directory, stem) {
+      throw Error("not supported");
+    },
   };
 }
 
@@ -172,11 +181,10 @@ export async function createNativeWalletHost2(
   args: DefaultNodeWalletArgs = {},
 ): Promise<{
   wallet: Wallet;
-  getDbStats: () => AccessStats;
 }> {
   BridgeIDBFactory.enableTracing = false;
 
-  let dbResp: MakeDbResult;
+  let dbResp: WalletDatabaseImplementation;
 
   if (
     args.persistentStoragePath &&
@@ -189,8 +197,6 @@ export async function createNativeWalletHost2(
     dbResp = await makeSqliteDb(args);
   }
 
-  const myIdbFactory: IDBFactory = dbResp.idbFactory as any as IDBFactory;
-
   shimIndexedDB(dbResp.idbFactory);
 
   const myHttpFactory = (config: WalletRunConfig) => {
@@ -211,18 +217,12 @@ export async function createNativeWalletHost2(
 
   const timer = new SetTimeoutTimerAPI();
 
-  const w = await Wallet.create(
-    myIdbFactory,
-    myHttpFactory,
-    timer,
-    workerFactory,
-  );
+  const w = await Wallet.create(dbResp, myHttpFactory, timer, workerFactory);
 
   if (args.notifyHandler) {
     w.addNotificationListener(args.notifyHandler);
   }
   return {
     wallet: w,
-    getDbStats: dbResp.getStats,
   };
 }
diff --git a/packages/taler-wallet-core/src/host.ts b/packages/taler-wallet-core/src/host.ts
index feccf42a6..ed1377d56 100644
--- a/packages/taler-wallet-core/src/host.ts
+++ b/packages/taler-wallet-core/src/host.ts
@@ -14,10 +14,9 @@
  GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 
+import * as hostImpl from "#host-impl";
 import { DefaultNodeWalletArgs } from "./host-common.js";
 import { Wallet } from "./index.js";
-import * as hostImpl from "#host-impl";
-import { AccessStats } from "@gnu-taler/idb-bridge";
 
 /**
  * Helpers to initiate a wallet in a host environment.
@@ -30,7 +29,6 @@ export async function createNativeWalletHost2(
   args: DefaultNodeWalletArgs = {},
 ): Promise<{
   wallet: Wallet;
-  getDbStats: () => AccessStats;
 }> {
   return hostImpl.createNativeWalletHost2(args);
 }
diff --git a/packages/taler-wallet-core/src/wallet-api-types.ts b/packages/taler-wallet-core/src/wallet-api-types.ts
index 79d918018..609a23d1e 100644
--- a/packages/taler-wallet-core/src/wallet-api-types.ts
+++ b/packages/taler-wallet-core/src/wallet-api-types.ts
@@ -66,6 +66,8 @@ import {
   EmptyObject,
   ExchangeDetailedResponse,
   ExchangesListResponse,
+  ExportDbToFileRequest,
+  ExportDbToFileResponse,
   FailTransactionRequest,
   ForceRefreshRequest,
   ForgetKnownBankAccountsRequest,
@@ -241,6 +243,7 @@ export enum WalletApiOperation {
   SetWalletDeviceId = "setWalletDeviceId",
   ImportDb = "importDb",
   ExportDb = "exportDb",
+  ExportDbToFile = "exportDbToFile",
   PreparePeerPushCredit = "preparePeerPushCredit",
   CheckPeerPushDebit = "checkPeerPushDebit",
   InitiatePeerPushDebit = "initiatePeerPushDebit",
@@ -280,6 +283,7 @@ export enum WalletApiOperation {
   TestingWaitTransactionState = "testingWaitTransactionState",
   TestingWaitExchangeState = "testingWaitExchangeState",
   TestingWaitTasksDone = "testingWaitTasksDone",
+  TestingGetDbStats = "testingGetDbStats",
   TestingSetTimetravel = "testingSetTimetravel",
   TestingGetDenomStats = "testingGetDenomStats",
   TestingPing = "testingPing",
@@ -871,6 +875,17 @@ export type ExportBackupOp = {
 };
 
 /**
+ * Export the database to a file.
+ *
+ * The target directory must already exist.
+ */
+export type ExportDbToFileOp = {
+  op: WalletApiOperation.ExportDbToFile;
+  request: ExportDbToFileRequest;
+  response: ExportDbToFileResponse;
+};
+
+/**
  * Add a new backup provider.
  */
 export type AddBackupProviderOp = {
@@ -1189,6 +1204,15 @@ export type TestingSetTimetravelOp = {
 };
 
 /**
+ * Add an offset to the wallet's internal time.
+ */
+export type TestingGetDbStats = {
+  op: WalletApiOperation.TestingSetTimetravel;
+  request: EmptyObject;
+  response: any;
+};
+
+/**
  * Wait until all transactions are in a final state.
  */
 export type TestingWaitTransactionsFinalOp = {
@@ -1343,6 +1367,7 @@ export type WalletOperations = {
   [WalletApiOperation.ImportBackupRecovery]: ImportBackupRecoveryOp;
   [WalletApiOperation.RunBackupCycle]: RunBackupCycleOp;
   [WalletApiOperation.ExportBackup]: ExportBackupOp;
+  [WalletApiOperation.ExportDbToFile]: ExportDbToFileOp;
   [WalletApiOperation.AddBackupProvider]: AddBackupProviderOp;
   [WalletApiOperation.RemoveBackupProvider]: RemoveBackupProviderOp;
   [WalletApiOperation.GetBackupInfo]: GetBackupInfoOp;
@@ -1368,6 +1393,7 @@ export type WalletOperations = {
   [WalletApiOperation.TestingWaitTransactionsFinal]: TestingWaitTransactionsFinalOp;
   [WalletApiOperation.TestingWaitRefreshesFinal]: TestingWaitRefreshesFinalOp;
   [WalletApiOperation.TestingSetTimetravel]: TestingSetTimetravelOp;
+  [WalletApiOperation.TestingGetDbStats]: TestingGetDbStats;
   [WalletApiOperation.TestingWaitTransactionState]: TestingWaitTransactionStateOp;
   [WalletApiOperation.TestingWaitExchangeState]: TestingWaitExchangeStateOp;
   [WalletApiOperation.TestingWaitTasksDone]: TestingWaitTasksDoneOp;
diff --git a/packages/taler-wallet-core/src/wallet.ts b/packages/taler-wallet-core/src/wallet.ts
index cdc066d85..1a70685c7 100644
--- a/packages/taler-wallet-core/src/wallet.ts
+++ b/packages/taler-wallet-core/src/wallet.ts
@@ -22,7 +22,11 @@
 /**
  * Imports.
  */
-import { IDBDatabase, IDBFactory } from "@gnu-taler/idb-bridge";
+import {
+  AccessStats,
+  BridgeIDBFactory,
+  IDBDatabase,
+} from "@gnu-taler/idb-bridge";
 import {
   AbortTransactionRequest,
   AbsoluteTime,
@@ -53,6 +57,8 @@ import {
   DenominationInfo,
   Duration,
   EmptyObject,
+  ExportDbToFileRequest,
+  ExportDbToFileResponse,
   FailTransactionRequest,
   ForgetKnownBankAccountsRequest,
   GetActiveTasksResponse,
@@ -144,6 +150,7 @@ import {
   codecForDeleteStoredBackupRequest,
   codecForDeleteTransactionRequest,
   codecForEmptyObject,
+  codecForExportDbToFileRequest,
   codecForFailTransactionRequest,
   codecForForceRefreshRequest,
   codecForForgetKnownBankAccounts,
@@ -689,8 +696,8 @@ async function getClientFromWalletState(
 async function createStoredBackup(
   wex: WalletExecutionContext,
 ): Promise<CreateStoredBackupResponse> {
-  const backup = await exportDb(wex.ws.idb);
-  const backupsDb = await openStoredBackupsDatabase(wex.ws.idb);
+  const backup = await exportDb(wex.ws.idbFactory);
+  const backupsDb = await openStoredBackupsDatabase(wex.ws.idbFactory);
   const name = `backup-${new Date().getTime()}`;
   await backupsDb.runAllStoresReadWriteTx({}, async (tx) => {
     await tx.backupMeta.add({
@@ -709,7 +716,7 @@ async function listStoredBackups(
   const storedBackups: StoredBackupList = {
     storedBackups: [],
   };
-  const backupsDb = await openStoredBackupsDatabase(wex.ws.idb);
+  const backupsDb = await openStoredBackupsDatabase(wex.ws.idbFactory);
   await backupsDb.runAllStoresReadWriteTx({}, async (tx) => {
     await tx.backupMeta.iter().forEach((x) => {
       storedBackups.storedBackups.push({
@@ -724,7 +731,7 @@ async function deleteStoredBackup(
   wex: WalletExecutionContext,
   req: DeleteStoredBackupRequest,
 ): Promise<void> {
-  const backupsDb = await openStoredBackupsDatabase(wex.ws.idb);
+  const backupsDb = await openStoredBackupsDatabase(wex.ws.idbFactory);
   await backupsDb.runAllStoresReadWriteTx({}, async (tx) => {
     await tx.backupData.delete(req.name);
     await tx.backupMeta.delete(req.name);
@@ -737,7 +744,7 @@ async function recoverStoredBackup(
 ): Promise<void> {
   logger.info(`Recovering stored backup ${req.name}`);
   const { name } = req;
-  const backupsDb = await openStoredBackupsDatabase(wex.ws.idb);
+  const backupsDb = await openStoredBackupsDatabase(wex.ws.idbFactory);
   const bd = await backupsDb.runAllStoresReadWriteTx({}, async (tx) => {
     const backupMeta = tx.backupMeta.get(name);
     if (!backupMeta) {
@@ -1443,6 +1450,19 @@ async function handleCreateStoredBackup(
   return await createStoredBackup(wex);
 }
 
+async function handleExportDbToFile(
+  wex: WalletExecutionContext,
+  req: ExportDbToFileRequest,
+): Promise<ExportDbToFileResponse> {
+  const res = await wex.ws.dbImplementation.exportToFile(
+    req.directory,
+    req.stem,
+  );
+  return {
+    path: res.path,
+  };
+}
+
 async function handleAcceptBankIntegratedWithdrawal(
   wex: WalletExecutionContext,
   req: AcceptBankIntegratedWithdrawalRequest,
@@ -1556,6 +1576,16 @@ const handlers: { [T in WalletApiOperation]: HandlerWithValidator<T> } = {
     codec: codecForAny(),
     handler: handleTestingWaitExchangeState,
   },
+  [WalletApiOperation.TestingGetDbStats]: {
+    codec: codecForEmptyObject(),
+    handler: async (wex) => {
+      return wex.ws.dbImplementation.getStats();
+    },
+  },
+  [WalletApiOperation.ExportDbToFile]: {
+    codec: codecForExportDbToFileRequest(),
+    handler: handleExportDbToFile,
+  },
   [WalletApiOperation.HintApplicationResumed]: {
     codec: codecForEmptyObject(),
     handler: handleHintApplicationResumed,
@@ -1937,7 +1967,7 @@ const handlers: { [T in WalletApiOperation]: HandlerWithValidator<T> } = {
   [WalletApiOperation.ExportDb]: {
     codec: codecForEmptyObject(),
     handler: async (wex, req) => {
-      const dbDump = await exportDb(wex.ws.idb);
+      const dbDump = await exportDb(wex.ws.idbFactory);
       return dbDump;
     },
   },
@@ -2292,6 +2322,12 @@ function applyRunConfigDefaults(wcp?: PartialWalletRunConfig): WalletRunConfig {
 
 export type HttpFactory = (config: WalletRunConfig) => HttpRequestLibrary;
 
+export interface WalletDatabaseImplementation {
+  idbFactory: BridgeIDBFactory;
+  getStats: () => AccessStats;
+  exportToFile: (directory: string, stem: string) => Promise<{ path: string }>;
+}
+
 /**
  * Public handle to a running wallet.
  */
@@ -2300,13 +2336,13 @@ export class Wallet {
   private _client: WalletCoreApiClient | undefined;
 
   private constructor(
-    idb: IDBFactory,
+    dbImplementation: WalletDatabaseImplementation,
     httpFactory: HttpFactory,
     timer: TimerAPI,
     cryptoWorkerFactory: CryptoWorkerFactory,
   ) {
     this.ws = new InternalWalletState(
-      idb,
+      dbImplementation,
       httpFactory,
       timer,
       cryptoWorkerFactory,
@@ -2321,12 +2357,17 @@ export class Wallet {
   }
 
   static async create(
-    idb: IDBFactory,
+    dbImplementation: WalletDatabaseImplementation,
     httpFactory: HttpFactory,
     timer: TimerAPI,
     cryptoWorkerFactory: CryptoWorkerFactory,
   ): Promise<Wallet> {
-    const w = new Wallet(idb, httpFactory, timer, cryptoWorkerFactory);
+    const w = new Wallet(
+      dbImplementation,
+      httpFactory,
+      timer,
+      cryptoWorkerFactory,
+    );
     w._client = await getClientFromWalletState(w.ws);
     return w;
   }
@@ -2484,6 +2525,10 @@ export class InternalWalletState {
 
   private longpollRequestIdCounter = 1;
 
+  public get idbFactory(): BridgeIDBFactory {
+    return this.dbImplementation.idbFactory;
+  }
+
   get db(): DbAccess<typeof WalletStoresV1> {
     if (!this._dbAccessHandle) {
       this._dbAccessHandle = this.createDbAccessHandle(
@@ -2616,7 +2661,7 @@ export class InternalWalletState {
   }
 
   constructor(
-    public idb: IDBFactory,
+    public dbImplementation: WalletDatabaseImplementation,
     private httpFactory: HttpFactory,
     public timer: TimerAPI,
     cryptoWorkerFactory: CryptoWorkerFactory,
@@ -2634,7 +2679,7 @@ export class InternalWalletState {
       logger.info("version change requested for Taler DB");
     };
     try {
-      const myDb = await openTalerDatabase(this.idb, myVersionChange);
+      const myDb = await openTalerDatabase(this.idbFactory, myVersionChange);
       this._indexedDbHandle = myDb;
     } catch (e) {
       logger.error("error writing to database during initialization");
diff --git a/packages/taler-wallet-embedded/src/wallet-qjs-tests.ts b/packages/taler-wallet-embedded/src/wallet-qjs-tests.ts
index ca4eb28c0..89db976a4 100644
--- a/packages/taler-wallet-embedded/src/wallet-qjs-tests.ts
+++ b/packages/taler-wallet-embedded/src/wallet-qjs-tests.ts
@@ -91,7 +91,11 @@ export async function testWithLocal(path: string) {
   await w.wallet.client.call(WalletApiOperation.TestingWaitTasksDone, {});
   console.log("done with task loop");
   await w.wallet.client.call(WalletApiOperation.Shutdown, {});
-  console.log("DB stats:", j2s(w.getDbStats()));
+  const stats = await w.wallet.client.call(
+    WalletApiOperation.TestingGetDbStats,
+    {},
+  );
+  console.log("DB stats:", j2s(stats));
 }
 
 export async function testArgon2id() {