썸네일이 누락된 파일 조회 및 레거시 파일 조회 네트워크 호출 최적화

src/lib/modules/filesystem/common.ts

@@ -0,0 +1,50 @@
+import { unwrapDataKey, decryptString } from "$lib/modules/crypto";
+
+export const decryptDirectoryMetadata = async (
+  metadata: { dek: string; dekVersion: Date; name: string; nameIv: string },
+  masterKey: CryptoKey,
+) => {
+  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
+  const name = await decryptString(metadata.name, metadata.nameIv, dataKey);
+
+  return {
+    dataKey: { key: dataKey, version: metadata.dekVersion },
+    name,
+  };
+};
+
+const decryptDate = async (ciphertext: string, iv: string, dataKey: CryptoKey) => {
+  return new Date(parseInt(await decryptString(ciphertext, iv, dataKey), 10));
+};
+
+export const decryptFileMetadata = async (
+  metadata: {
+    dek: string;
+    dekVersion: Date;
+    name: string;
+    nameIv: string;
+    createdAt?: string;
+    createdAtIv?: string;
+    lastModifiedAt: string;
+    lastModifiedAtIv: string;
+  },
+  masterKey: CryptoKey,
+) => {
+  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
+  const [name, createdAt, lastModifiedAt] = await Promise.all([
+    decryptString(metadata.name, metadata.nameIv, dataKey),
+    metadata.createdAt
+      ? decryptDate(metadata.createdAt, metadata.createdAtIv!, dataKey)
+      : undefined,
+    decryptDate(metadata.lastModifiedAt, metadata.lastModifiedAtIv, dataKey),
+  ]);
+
+  return {
+    dataKey: { key: dataKey, version: metadata.dekVersion },
+    name,
+    createdAt,
+    lastModifiedAt,
+  };
+};
+
+export const decryptCategoryMetadata = decryptDirectoryMetadata;