파일 다운로드 임시 구현

src/lib/modules/crypto/aes.ts

@@ -1,4 +1,4 @@
-import { encodeToBase64, decodeFromBase64 } from "./util";
+import { encodeString, decodeString, encodeToBase64, decodeFromBase64 } from "./util";
 
 export const generateMasterKey = async () => {
   return {
@@ -81,3 +81,12 @@ export const decryptData = async (ciphertext: BufferSource, iv: string, dataKey:
     ciphertext,
   );
 };
+
+export const encryptString = async (plaintext: string, dataKey: CryptoKey) => {
+  const { ciphertext, iv } = await encryptData(encodeString(plaintext), dataKey);
+  return { ciphertext: encodeToBase64(ciphertext), iv };
+};
+
+export const decryptString = async (ciphertext: string, iv: string, dataKey: CryptoKey) => {
+  return decodeString(await decryptData(decodeFromBase64(ciphertext), iv, dataKey));
+};

src/lib/modules/crypto/util.ts

@@ -1,3 +1,14 @@
+const textEncoder = new TextEncoder();
+const textDecoder = new TextDecoder();
+
+export const encodeString = (data: string) => {
+  return textEncoder.encode(data);
+};
+
+export const decodeString = (data: ArrayBuffer) => {
+  return textDecoder.decode(data);
+};
+
 export const encodeToBase64 = (data: ArrayBuffer) => {
   return btoa(String.fromCharCode(...new Uint8Array(data)));
 };

src/lib/services/file.ts

@@ -0,0 +1,10 @@
+import { unwrapDataKey, decryptString } from "$lib/modules/crypto";
+import type { FileInfoResponse } from "$lib/server/schemas";
+
+export const decryptFileMetadata = async (metadata: FileInfoResponse, masterKey: CryptoKey) => {
+  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
+  return {
+    dataKey,
+    name: await decryptString(metadata.name, metadata.nameIv, dataKey),
+  };
+};

src/routes/(fullscreen)/file/[id]/+page.svelte

@@ -0,0 +1,42 @@
+<script lang="ts">
+  import FileSaver from "file-saver";
+  import { TopBar } from "$lib/components";
+  import { masterKeyStore } from "$lib/stores";
+  import { decryptFileMetadata, requestFileDownload } from "./service";
+
+  let { data } = $props();
+
+  let metadata = $state<Awaited<ReturnType<typeof decryptFileMetadata>> | undefined>();
+
+  $effect(() => {
+    if ($masterKeyStore) {
+      decryptFileMetadata(data.metadata, $masterKeyStore.get(data.metadata.mekVersion)!.key).then(
+        async (_metadata) => {
+          metadata = _metadata;
+
+          const file = await requestFileDownload(
+            data.id,
+            data.metadata.contentIv,
+            _metadata.dataKey,
+          );
+
+          // TODO: Preview
+
+          const blob = new Blob([file]);
+
+          FileSaver.saveAs(blob, metadata.name);
+        },
+      );
+    }
+  });
+</script>
+
+<svelte:head>
+  <title>파일</title>
+</svelte:head>
+
+{#if metadata}
+  <TopBar title={metadata.name} />
+{:else}
+  <TopBar />
+{/if}

src/routes/(fullscreen)/file/[id]/+page.ts

@@ -0,0 +1,24 @@
+import { error } from "@sveltejs/kit";
+import { z } from "zod";
+import { callGetApi } from "$lib/hooks";
+import type { FileInfoResponse } from "$lib/server/schemas";
+import type { PageLoad } from "./$types";
+
+export const load: PageLoad = async ({ params, fetch }) => {
+  const zodRes = z
+    .object({
+      id: z.coerce.number().int().positive(),
+    })
+    .safeParse(params);
+  if (!zodRes.success) error(404, "Not found");
+  const { id } = zodRes.data;
+
+  const res = await callGetApi(`/api/file/${id}`, fetch);
+  if (!res.ok) error(404, "Not found");
+
+  const fileInfo: FileInfoResponse = await res.json();
+  return {
+    id,
+    metadata: fileInfo,
+  };
+};

src/routes/(fullscreen)/file/[id]/service.ts

@@ -0,0 +1,33 @@
+import { decryptData } from "$lib/modules/crypto";
+
+export { decryptFileMetadata } from "$lib/services/file";
+
+export const requestFileDownload = (
+  fileId: number,
+  fileEncryptedIv: string,
+  dataKey: CryptoKey,
+) => {
+  return new Promise<ArrayBuffer>((resolve, reject) => {
+    const xhr = new XMLHttpRequest();
+    xhr.responseType = "arraybuffer";
+
+    xhr.addEventListener("load", async () => {
+      if (xhr.status !== 200) {
+        reject(new Error("Failed to download file"));
+        return;
+      }
+
+      const fileDecrypted = await decryptData(
+        xhr.response as ArrayBuffer,
+        fileEncryptedIv,
+        dataKey,
+      );
+      resolve(fileDecrypted);
+    });
+
+    // TODO: Progress, ...
+
+    xhr.open("GET", `/api/file/${fileId}/download`);
+    xhr.send();
+  });
+};

src/routes/(main)/directory/[[id]]/service.ts

@@ -1,12 +1,12 @@
 import { callSignedPostApi } from "$lib/hooks";
 import {
   encodeToBase64,
-  decodeFromBase64,
   generateDataKey,
   wrapDataKey,
   unwrapDataKey,
   encryptData,
-  decryptData,
+  encryptString,
+  decryptString,
   digestMessage,
   signRequestBody,
 } from "$lib/modules/crypto";
@@ -14,28 +14,18 @@ import type {
   DirectroyInfoResponse,
   DirectoryCreateRequest,
   FileUploadRequest,
-  FileInfoResponse,
 } from "$lib/server/schemas";
 import type { MasterKey } from "$lib/stores";
 
+export { decryptFileMetadata } from "$lib/services/file";
+
 export const decryptDirectroyMetadata = async (
   metadata: NonNullable<DirectroyInfoResponse["metadata"]>,
   masterKey: CryptoKey,
 ) => {
   const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
   return {
-    name: new TextDecoder().decode(
-      await decryptData(decodeFromBase64(metadata.name), metadata.nameIv, dataKey),
-    ),
-  };
-};
-
-export const decryptFileMetadata = async (metadata: FileInfoResponse, masterKey: CryptoKey) => {
-  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
-  return {
-    name: new TextDecoder().decode(
-      await decryptData(decodeFromBase64(metadata.name), metadata.nameIv, dataKey),
-    ),
+    name: await decryptString(metadata.name, metadata.nameIv, dataKey),
   };
 };
 
@@ -69,7 +59,7 @@ export const requestFileUpload = async (
   const { dataKey } = await generateDataKey();
   const fileEncrypted = await encryptData(await file.arrayBuffer(), dataKey);
   const fileEncryptedHash = await digestMessage(fileEncrypted.ciphertext);
-  const nameEncrypted = await encryptData(new TextEncoder().encode(file.name), dataKey);
+  const nameEncrypted = await encryptString(file.name, dataKey);
 
   const form = new FormData();
   form.set(
@@ -81,7 +71,7 @@ export const requestFileUpload = async (
         dek: await wrapDataKey(dataKey, masterKey.key),
         contentHash: encodeToBase64(fileEncryptedHash),
         contentIv: fileEncrypted.iv,
-        name: encodeToBase64(nameEncrypted.ciphertext),
+        name: nameEncrypted.ciphertext,
         nameIv: nameEncrypted.iv,
       },
       signKey,