(feat): add cache package

(feat): improve local storage security
(feat): move settings to dedicated settings package

apps/electron/src/main/secureStorage.ts

@@ -0,0 +1,130 @@
+import { app, safeStorage } from "electron";
+import { mkdir, readFile, rename, writeFile } from "node:fs/promises";
+import { dirname, join } from "node:path";
+import {
+  secureStorageLimits,
+  type DesktopSecureStorageStatus,
+} from "../shared/ipc.js";
+
+type StoredValues = Record<string, string>;
+
+let pendingWrite = Promise.resolve();
+
+function storagePath() {
+  return join(app.getPath("userData"), "secure-storage.json");
+}
+
+function validateKey(key: unknown): asserts key is string {
+  if (
+    typeof key !== "string" ||
+    key.length === 0 ||
+    Buffer.byteLength(key, "utf8") > secureStorageLimits.maxKeyBytes
+  ) {
+    throw new Error("Invalid secure storage key.");
+  }
+}
+
+function validateValue(value: unknown): asserts value is string {
+  if (
+    typeof value !== "string" ||
+    Buffer.byteLength(value, "utf8") > secureStorageLimits.maxValueBytes
+  ) {
+    throw new Error("Invalid secure storage value.");
+  }
+}
+
+export function getSecureStorageStatus(): DesktopSecureStorageStatus {
+  if (!safeStorage.isEncryptionAvailable()) {
+    return { available: false, backend: null };
+  }
+
+  const backend =
+    process.platform === "linux"
+      ? safeStorage.getSelectedStorageBackend()
+      : process.platform === "darwin"
+        ? "keychain"
+        : process.platform === "win32"
+          ? "dpapi"
+          : null;
+
+  return {
+    available: process.platform !== "linux" || backend !== "basic_text",
+    backend,
+  };
+}
+
+function requireAvailable() {
+  if (!getSecureStorageStatus().available) {
+    throw new Error("Secure storage is unavailable.");
+  }
+}
+
+async function readValues(): Promise<StoredValues> {
+  try {
+    const parsed: unknown = JSON.parse(await readFile(storagePath(), "utf8"));
+    if (!parsed || typeof parsed !== "object" || Array.isArray(parsed)) {
+      throw new Error("Invalid secure storage data.");
+    }
+
+    const values = parsed as Record<string, unknown>;
+    if (Object.values(values).some((value) => typeof value !== "string")) {
+      throw new Error("Invalid secure storage data.");
+    }
+    return values as StoredValues;
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code === "ENOENT") return {};
+    throw error;
+  }
+}
+
+async function writeValues(values: StoredValues) {
+  const path = storagePath();
+  const temporaryPath = `${path}.tmp`;
+  await mkdir(dirname(path), { recursive: true, mode: 0o700 });
+  await writeFile(temporaryPath, JSON.stringify(values), { mode: 0o600 });
+  await rename(temporaryPath, path);
+}
+
+function mutateValues(mutation: (values: StoredValues) => void) {
+  const operation = pendingWrite.then(async () => {
+    const values = await readValues();
+    mutation(values);
+    await writeValues(values);
+  });
+  pendingWrite = operation.catch(() => undefined);
+  return operation;
+}
+
+export async function loadSecureStorage(key: unknown): Promise<string | null> {
+  requireAvailable();
+  validateKey(key);
+  await pendingWrite;
+  const encrypted = (await readValues())[key];
+  if (encrypted === undefined) return null;
+  return safeStorage.decryptString(Buffer.from(encrypted, "base64"));
+}
+
+export function saveSecureStorage(key: unknown, value: unknown) {
+  requireAvailable();
+  validateKey(key);
+  validateValue(value);
+  const encrypted = safeStorage.encryptString(value).toString("base64");
+  return mutateValues((values) => {
+    values[key] = encrypted;
+  });
+}
+
+export function deleteSecureStorage(key: unknown) {
+  requireAvailable();
+  validateKey(key);
+  return mutateValues((values) => {
+    delete values[key];
+  });
+}
+
+export function clearSecureStorage() {
+  requireAvailable();
+  return mutateValues((values) => {
+    for (const key of Object.keys(values)) delete values[key];
+  });
+}