썸네일을 메모리와 OPFS에 캐시하도록 개선

src/lib/modules/file/index.ts

@@ -1,3 +1,4 @@
 export * from "./cache";
 export * from "./download";
+export * from "./thumbnail";
 export * from "./upload";

src/lib/modules/file/thumbnail.ts

@@ -0,0 +1,29 @@
+import { LRUCache } from "lru-cache";
+import { readFile, writeFile, deleteFile } from "$lib/modules/opfs";
+import { getThumbnailUrl } from "$lib/modules/thumbnail";
+
+const loadedThumbnails = new LRUCache<number, string>({ max: 100 });
+
+export const getFileThumbnail = async (fileId: number) => {
+  const thumbnail = loadedThumbnails.get(fileId);
+  if (thumbnail) {
+    return thumbnail;
+  }
+
+  const thumbnailBuffer = await readFile(`/thumbnails/${fileId}`);
+  if (!thumbnailBuffer) return null;
+
+  const thumbnailUrl = getThumbnailUrl(thumbnailBuffer);
+  loadedThumbnails.set(fileId, thumbnailUrl);
+  return thumbnailUrl;
+};
+
+export const storeFileThumbnail = async (fileId: number, thumbnailBuffer: ArrayBuffer) => {
+  await writeFile(`/thumbnails/${fileId}`, thumbnailBuffer);
+  loadedThumbnails.set(fileId, getThumbnailUrl(thumbnailBuffer));
+};
+
+export const deleteFileThumbnail = async (fileId: number) => {
+  loadedThumbnails.delete(fileId);
+  await deleteFile(`/thumbnails/${fileId}`);
+};

src/lib/modules/file/upload.ts

@@ -130,9 +130,8 @@ const encryptFile = limitFunction(
     const lastModifiedAtEncrypted = await encryptString(file.lastModified.toString(), dataKey);
 
     const thumbnail = await generateThumbnail(file, fileType);
-    const thumbnailEncrypted = thumbnail
-      ? await encryptData(await thumbnail.arrayBuffer(), dataKey)
-      : null;
+    const thumbnailBuffer = await thumbnail?.arrayBuffer();
+    const thumbnailEncrypted = thumbnailBuffer ? await encryptData(thumbnailBuffer, dataKey) : null;
 
     status.update((value) => {
       value.status = "upload-pending";
@@ -148,7 +147,8 @@ const encryptFile = limitFunction(
       nameEncrypted,
       createdAtEncrypted,
       lastModifiedAtEncrypted,
-      thumbnailEncrypted,
+      thumbnail: thumbnail &&
+        thumbnailEncrypted && { plaintext: thumbnailBuffer, ...thumbnailEncrypted },
     };
   },
   { concurrency: 4 },
@@ -198,7 +198,9 @@ export const uploadFile = async (
   hmacSecret: HmacSecret,
   masterKey: MasterKey,
   onDuplicate: () => Promise<boolean>,
-): Promise<{ fileId: number; fileBuffer: ArrayBuffer } | undefined> => {
+): Promise<
+  { fileId: number; fileBuffer: ArrayBuffer; thumbnailBuffer?: ArrayBuffer } | undefined
+> => {
   const status = writable<FileUploadStatus>({
     name: file.name,
     parentId,
@@ -236,7 +238,7 @@ export const uploadFile = async (
       nameEncrypted,
       createdAtEncrypted,
       lastModifiedAtEncrypted,
-      thumbnailEncrypted,
+      thumbnail,
     } = await encryptFile(status, file, fileBuffer, masterKey);
 
     const form = new FormData();
@@ -263,20 +265,20 @@ export const uploadFile = async (
     form.set("checksum", fileEncryptedHash);
 
     let thumbnailForm = null;
-    if (thumbnailEncrypted) {
+    if (thumbnail) {
       thumbnailForm = new FormData();
       thumbnailForm.set(
         "metadata",
         JSON.stringify({
           dekVersion: dataKeyVersion.toISOString(),
-          contentIv: thumbnailEncrypted.iv,
+          contentIv: thumbnail.iv,
         } satisfies FileThumbnailUploadRequest),
       );
-      thumbnailForm.set("content", new Blob([thumbnailEncrypted.ciphertext]));
+      thumbnailForm.set("content", new Blob([thumbnail.ciphertext]));
     }
 
     const { fileId } = await requestFileUpload(status, form, thumbnailForm);
-    return { fileId, fileBuffer };
+    return { fileId, fileBuffer, thumbnailBuffer: thumbnail?.plaintext };
   } catch (e) {
     status.update((value) => {
       value.status = "error";

src/lib/modules/thumbnail.ts

@@ -1,3 +1,5 @@
+import { encodeToBase64 } from "$lib/modules/crypto";
+
 const scaleSize = (width: number, height: number, targetSize: number) => {
   if (width <= targetSize || height <= targetSize) {
     return { width, height };
@@ -74,3 +76,7 @@ export const generateVideoThumbnail = (videoUrl: string, time = 0) => {
     video.src = videoUrl;
   });
 };
+
+export const getThumbnailUrl = (thumbnailBuffer: ArrayBuffer) => {
+  return `data:image/webp;base64,${encodeToBase64(thumbnailBuffer)}`;
+};