서버, 클라이언트, 서비스 워커 공용 코드를 lib/shared로 분리하고 브라우저 전용 모듈을 lib/client로 재구성

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/service-worker/constants.ts

@@ -1 +0,0 @@
-export * from "../lib/constants";

src/service-worker/handlers/decryptFile.ts

@@ -1,14 +1,25 @@
-import { DECRYPTED_FILE_URL_PREFIX, CHUNK_SIZE, ENCRYPTED_CHUNK_SIZE } from "../constants";
-import { decryptChunk, getEncryptedRange, getDecryptedSize } from "../modules/crypto";
-import { parseRangeHeader, getContentRangeHeader } from "../modules/http";
+import { getFile } from "#lib/client/storage/opfs.js";
+import { decryptChunk } from "#lib/shared/crypto/index.js";
+import {
+  CHUNK_SIZE,
+  ENCRYPTED_CHUNK_SIZE,
+  getDecryptedSize,
+  getEncryptedRange,
+} from "#lib/shared/format/index.js";
+import {
+  getContentRangeHeader,
+  parseRangeHeader,
+  resolveRange,
+  type ByteRange,
+  type RangeRequest,
+} from "#lib/shared/http.js";
+import { DECRYPTED_FILE_URL_PREFIX, type FileMetadata } from "#lib/shared/serviceWorker.js";
 import { getFileMetadata } from "../modules/metadata";
-import { getFile } from "../modules/opfs";
-import type { FileMetadata } from "../types";
 
 const createResponse = (
   stream: ReadableStream<Uint8Array>,
   isRangeRequest: boolean,
-  range: { start: number; end: number; total: number },
+  range: ByteRange,
   contentType?: string,
   downloadFilename?: string,
 ) => {
@@ -33,22 +44,28 @@ const createResponse = (
   });
 };
 
+const createRangeNotSatisfiableResponse = (total: number) => {
+  return new Response("Invalid range", {
+    status: 416,
+    headers: { "Content-Range": `bytes */${total}` },
+  });
+};
+
 const streamFromOpfs = async (
   file: File,
   metadata?: FileMetadata,
-  range?: { start?: number; end?: number },
+  rangeRequest?: RangeRequest,
   downloadFilename?: string,
 ) => {
-  const start = range?.start ?? 0;
-  const end = range?.end ?? file.size - 1;
-  if (start > end || start < 0 || end >= file.size) {
-    return new Response("Invalid range", { status: 416 });
+  const range = resolveRange(rangeRequest, file.size);
+  if (!range) {
+    return createRangeNotSatisfiableResponse(file.size);
   }
 
   return createResponse(
-    file.slice(start, end + 1).stream(),
-    !!range,
-    { start, end, total: file.size },
+    file.slice(range.start, range.end + 1).stream(),
+    !!rangeRequest,
+    range,
     metadata?.contentType,
     downloadFilename,
   );
@@ -57,16 +74,16 @@ const streamFromOpfs = async (
 const streamFromServer = async (
   id: number,
   metadata: FileMetadata,
-  range?: { start?: number; end?: number },
+  rangeRequest?: RangeRequest,
   downloadFilename?: string,
 ) => {
   const totalSize = getDecryptedSize(metadata.encContentSize, metadata.isLegacy);
-  const start = range?.start ?? 0;
-  const end = range?.end ?? totalSize - 1;
-  if (start > end || start < 0 || end >= totalSize) {
-    return new Response("Invalid range", { status: 416 });
+  const range = resolveRange(rangeRequest, totalSize);
+  if (!range) {
+    return createRangeNotSatisfiableResponse(totalSize);
   }
 
+  const { start, end } = range;
   const encryptedRange = getEncryptedRange(start, end, metadata.encContentSize, metadata.isLegacy);
   const apiResponse = await fetch(`/api/file/${id}/download`, {
     headers: { Range: `bytes=${encryptedRange.start}-${encryptedRange.end}` },
@@ -85,9 +102,10 @@ const streamFromServer = async (
           controller.close();
         },
       }),
-      !!range,
-      { start, end, total: totalSize },
+      !!rangeRequest,
+      range,
       metadata.contentType,
+      downloadFilename,
     );
   }
 
@@ -124,8 +142,8 @@ const streamFromServer = async (
 
   return createResponse(
     apiResponse.body.pipeThrough(decryptingStream),
-    !!range,
-    { start, end, total: totalSize },
+    !!rangeRequest,
+    range,
     metadata.contentType,
     downloadFilename,
   );

src/service-worker/index.ts

@@ -1,8 +1,11 @@
 import { self } from "$app/service-worker";
-import { DECRYPTED_FILE_URL_PREFIX } from "./constants";
+import {
+  DECRYPTED_FILE_URL_PREFIX,
+  type ServiceWorkerMessage,
+  type ServiceWorkerResponse,
+} from "#lib/shared/serviceWorker.js";
 import { decryptFile } from "./handlers";
 import { fileMetadataStore } from "./stores";
-import type { ServiceWorkerMessage, ServiceWorkerResponse } from "./types";
 
 self.addEventListener("message", (event) => {
   const message: ServiceWorkerMessage = event.data;

src/service-worker/modules/crypto.ts

@@ -1,40 +0,0 @@
-import { ENCRYPTION_OVERHEAD, CHUNK_SIZE, ENCRYPTED_CHUNK_SIZE } from "../constants";
-
-export * from "../../lib/modules/crypto";
-
-export const getEncryptedRange = (
-  start: number,
-  end: number,
-  totalEncryptedSize: number,
-  isLegacy: boolean,
-) => {
-  if (isLegacy) {
-    return {
-      firstChunkIndex: 0,
-      lastChunkIndex: 0,
-      start: 0,
-      end: totalEncryptedSize - 1,
-    };
-  }
-
-  const firstChunkIndex = Math.floor(start / CHUNK_SIZE);
-  const lastChunkIndex = Math.floor(end / CHUNK_SIZE);
-  return {
-    firstChunkIndex,
-    lastChunkIndex,
-    start: firstChunkIndex * ENCRYPTED_CHUNK_SIZE,
-    end: Math.min((lastChunkIndex + 1) * ENCRYPTED_CHUNK_SIZE - 1, totalEncryptedSize - 1),
-  };
-};
-
-export const getDecryptedSize = (encryptedSize: number, isLegacy: boolean) => {
-  if (isLegacy) {
-    return encryptedSize - ENCRYPTION_OVERHEAD;
-  }
-
-  const fullChunks = Math.floor(encryptedSize / ENCRYPTED_CHUNK_SIZE);
-  const lastChunkEncSize = encryptedSize % ENCRYPTED_CHUNK_SIZE;
-  return (
-    fullChunks * CHUNK_SIZE + (lastChunkEncSize > 0 ? lastChunkEncSize - ENCRYPTION_OVERHEAD : 0)
-  );
-};

src/service-worker/modules/http.ts

@@ -1 +0,0 @@
-export * from "../../lib/modules/http";

src/service-worker/modules/metadata.ts

@@ -1,6 +1,6 @@
 import { self } from "$app/service-worker";
+import type { FileMetadata, ServiceWorkerResponse } from "#lib/shared/serviceWorker.js";
 import { fileMetadataStore } from "../stores";
-import type { FileMetadata, ServiceWorkerResponse } from "../types";
 
 const METADATA_REQUEST_TIMEOUT_MS = 3000;
 

src/service-worker/modules/opfs.ts

@@ -1 +0,0 @@
-export * from "../../lib/modules/opfs";

src/service-worker/stores.ts

@@ -1,4 +1,4 @@
-import type { FileMetadata } from "./types";
+import type { FileMetadata } from "#lib/shared/serviceWorker.js";
 
 const MAX_FILE_METADATA_ENTRIES = 32;
 

src/service-worker/types.ts

@@ -1 +0,0 @@
-export * from "../lib/serviceWorker/types";