Add a new RPC command: restorewallet

src/rpc/client.cpp

@@ -187,6 +187,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "createwallet", 5, "descriptors"},
     { "createwallet", 6, "load_on_startup"},
     { "createwallet", 7, "external_signer"},
+    { "restorewallet", 2, "load_on_startup"},
     { "loadwallet", 1, "load_on_startup"},
     { "unloadwallet", 1, "load_on_startup"},
     { "getnodeaddresses", 0, "count"},

src/wallet/rpcwallet.cpp

@@ -2572,6 +2572,37 @@ static RPCHelpMan listwallets()
     };
 }
 
+static std::tuple<std::shared_ptr<CWallet>, std::vector<bilingual_str>> LoadWalletHelper(WalletContext& context, UniValue load_on_start_param, const std::string wallet_name)
+{
+    DatabaseOptions options;
+    DatabaseStatus status;
+    options.require_existing = true;
+    bilingual_str error;
+    std::vector<bilingual_str> warnings;
+    std::optional<bool> load_on_start = load_on_start_param.isNull() ? std::nullopt : std::optional<bool>(load_on_start_param.get_bool());
+    std::shared_ptr<CWallet> const wallet = LoadWallet(*context.chain, wallet_name, load_on_start, options, status, error, warnings);
+
+    if (!wallet) {
+        // Map bad format to not found, since bad format is returned when the
+        // wallet directory exists, but doesn't contain a data file.
+        RPCErrorCode code = RPC_WALLET_ERROR;
+        switch (status) {
+            case DatabaseStatus::FAILED_NOT_FOUND:
+            case DatabaseStatus::FAILED_BAD_FORMAT:
+                code = RPC_WALLET_NOT_FOUND;
+                break;
+            case DatabaseStatus::FAILED_ALREADY_LOADED:
+                code = RPC_WALLET_ALREADY_LOADED;
+                break;
+            default: // RPC_WALLET_ERROR is returned for all other cases.
+                break;
+        }
+        throw JSONRPCError(code, error.original);
+    }
+
+    return { wallet, warnings };
+}
+
 static RPCHelpMan loadwallet()
 {
     return RPCHelpMan{"loadwallet",
@@ -2598,30 +2629,7 @@ static RPCHelpMan loadwallet()
     WalletContext& context = EnsureWalletContext(request.context);
     const std::string name(request.params[0].get_str());
 
-    DatabaseOptions options;
+    auto [wallet, warnings] = LoadWalletHelper(context, request.params[1], name);
-    DatabaseStatus status;
-    options.require_existing = true;
-    bilingual_str error;
-    std::vector<bilingual_str> warnings;
-    std::optional<bool> load_on_start = request.params[1].isNull() ? std::nullopt : std::optional<bool>(request.params[1].get_bool());
-    std::shared_ptr<CWallet> const wallet = LoadWallet(*context.chain, name, load_on_start, options, status, error, warnings);
-    if (!wallet) {
-        // Map bad format to not found, since bad format is returned when the
-        // wallet directory exists, but doesn't contain a data file.
-        RPCErrorCode code = RPC_WALLET_ERROR;
-        switch (status) {
-            case DatabaseStatus::FAILED_NOT_FOUND:
-            case DatabaseStatus::FAILED_BAD_FORMAT:
-                code = RPC_WALLET_NOT_FOUND;
-                break;
-            case DatabaseStatus::FAILED_ALREADY_LOADED:
-                code = RPC_WALLET_ALREADY_LOADED;
-                break;
-            default: // RPC_WALLET_ERROR is returned for all other cases.
-                break;
-        }
-        throw JSONRPCError(code, error.original);
-    }
 
     UniValue obj(UniValue::VOBJ);
     obj.pushKV("name", wallet->GetName());
@@ -2795,6 +2803,68 @@ static RPCHelpMan createwallet()
     };
 }
 
+static RPCHelpMan restorewallet()
+{
+    return RPCHelpMan{
+        "restorewallet",
+        "\nRestore and loads a wallet from backup.\n",
+        {
+            {"wallet_name", RPCArg::Type::STR, RPCArg::Optional::NO, "The name that will be applied to the restored wallet"},
+            {"backup_file", RPCArg::Type::STR, RPCArg::Optional::NO, "The backup file that will be used to restore the wallet."},
+            {"load_on_startup", RPCArg::Type::BOOL, RPCArg::Optional::OMITTED_NAMED_ARG, "Save wallet name to persistent settings and load on startup. True to add wallet to startup list, false to remove, null to leave unchanged."},
+        },
+        RPCResult{
+            RPCResult::Type::OBJ, "", "",
+            {
+                {RPCResult::Type::STR, "name", "The wallet name if restored successfully."},
+                {RPCResult::Type::STR, "warning", "Warning message if wallet was not loaded cleanly."},
+            }
+        },
+        RPCExamples{
+            HelpExampleCli("restorewallet", "\"testwallet\" \"home\\backups\\backup-file.bak\"")
+            + HelpExampleRpc("restorewallet", "\"testwallet\" \"home\\backups\\backup-file.bak\"")
+            + HelpExampleCliNamed("restorewallet", {{"wallet_name", "testwallet"}, {"backup_file", "home\\backups\\backup-file.bak\""}, {"load_on_startup", true}})
+            + HelpExampleRpcNamed("restorewallet", {{"wallet_name", "testwallet"}, {"backup_file", "home\\backups\\backup-file.bak\""}, {"load_on_startup", true}})
+        },
+        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
+{
+
+    WalletContext& context = EnsureWalletContext(request.context);
+
+    std::string backup_file = request.params[1].get_str();
+
+    if (!fs::exists(backup_file)) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Backup file does not exist");
+    }
+
+    std::string wallet_name = request.params[0].get_str();
+
+    const fs::path wallet_path = fsbridge::AbsPathJoin(GetWalletDir(), wallet_name);
+
+    if (fs::exists(wallet_path)) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Wallet name already exists.");
+    }
+
+    if (!TryCreateDirectories(wallet_path)) {
+        throw JSONRPCError(RPC_WALLET_ERROR, strprintf("Failed to create database path '%s'. Database already exists.", wallet_path.string()));
+    }
+
+    auto wallet_file = wallet_path / "wallet.dat";
+
+    fs::copy_file(backup_file, wallet_file, fs::copy_option::fail_if_exists);
+
+    auto [wallet, warnings] = LoadWalletHelper(context, request.params[2], wallet_name);
+
+    UniValue obj(UniValue::VOBJ);
+    obj.pushKV("name", wallet->GetName());
+    obj.pushKV("warning", Join(warnings, Untranslated("\n")).original);
+
+    return obj;
+
+},
+    };
+}
+
 static RPCHelpMan unloadwallet()
 {
     return RPCHelpMan{"unloadwallet",
@@ -4639,6 +4709,7 @@ static const CRPCCommand commands[] =
     { "wallet",             &bumpfee,                        },
     { "wallet",             &psbtbumpfee,                    },
     { "wallet",             &createwallet,                   },
+    { "wallet",             &restorewallet,                  },
     { "wallet",             &dumpprivkey,                    },
     { "wallet",             &dumpwallet,                     },
     { "wallet",             &encryptwallet,                  },