Merge pull request '避免页面更新打断图片下载' (#76) from codex/preserve-active-image-downloads-20261111 into main

app/layout.tsx

@@ -4,6 +4,7 @@ import { ThemeProvider } from "@/components/theme-provider";
 import { FaviconUpdater } from "@/components/favicon-updater";
 import { ImageDeliveryOptimizer } from "@/components/image-delivery-optimizer";
 import { AppUpdateNotice } from "@/components/app-update-notice";
+import { PAGE_DOWNLOAD_ACTIVE_ATTRIBUTE } from "@/lib/client/page-refresh";
 import { getSiteSettings } from "@/lib/db/queries";
 
 import "./globals.css";
@@ -142,7 +143,7 @@ const CHUNK_ERROR_RECOVERY_SCRIPT = `\
       showManualRecoveryNotice();
       return;
     }
-    if (lastReloadAt) return;
+    if (lastReloadAt || document.documentElement.hasAttribute('${PAGE_DOWNLOAD_ACTIVE_ATTRIBUTE}')) return;
     var now = Date.now();
     // If storage is blocked, a reload cannot remember its attempt and must not run.
     if (!safeSetSessionStorage(RECOVERY_KEY, String(now))) return;
@@ -153,6 +154,10 @@ const CHUNK_ERROR_RECOVERY_SCRIPT = `\
         showManualRecoveryNotice();
         return;
       }
+      if (document.documentElement.hasAttribute('${PAGE_DOWNLOAD_ACTIVE_ATTRIBUTE}')) {
+        if (safeSetSessionStorage(RECOVERY_KEY, '0')) lastReloadAt = 0;
+        return;
+      }
       window.location.reload();
     }, 800);
   }

components/app-update-notice.tsx

@@ -1,14 +1,15 @@
 "use client";
 
-import { useEffect, useState } from "react";
+import { useEffect, useState, useSyncExternalStore } from "react";
 import { Button } from "@/components/ui/button";
 import { AlertDialog, AlertDialogContent, AlertDialogHeader, AlertDialogTitle, AlertDialogDescription, AlertDialogFooter } from "@/components/ui/alert-dialog";
-import { preparePageRefresh } from "@/lib/client/page-refresh";
+import { isPageDownloadActive, preparePageRefresh, subscribeToPageDownloadActivity } from "@/lib/client/page-refresh";
 
 export function AppUpdateNotice() {
   const [availableVersion, setAvailableVersion] = useState("");
   const [refreshing, setRefreshing] = useState(false);
   const [error, setError] = useState("");
+  const downloading = useSyncExternalStore(subscribeToPageDownloadActivity, isPageDownloadActive, () => false);
   useEffect(() => {
     let disposed = false;
     let controller: AbortController | undefined;
@@ -60,7 +61,7 @@ export function AppUpdateNotice() {
       setRefreshing(false);
     }
   };
-  return <AlertDialog open={Boolean(availableVersion)}>
+  return <AlertDialog open={Boolean(availableVersion) && !downloading}>
     <AlertDialogContent className="z-[10001]" overlayClassName="z-[10000]" onEscapeKeyDown={event => event.preventDefault()}>
       <AlertDialogHeader>
         <AlertDialogTitle>平台已更新</AlertDialogTitle>

components/canvas/CanvasChatPanel.tsx

@@ -4467,7 +4467,6 @@ export function CanvasChatPanel({
     setDownloadProgress({
       phase: "preparing",
       message: "正在准备原图...",
-      percent: 5,
     });
 
     try {

components/canvas/CanvasImageDownloadProgressDialog.tsx

@@ -28,6 +28,7 @@ export function CanvasImageDownloadProgressDialog({
       : null;
   const loadedLabel = formatBytes(progress.loadedBytes);
   const totalLabel = formatBytes(progress.totalBytes);
+  const converting = progress.phase === "converting";
 
   return createPortal(
     <div
@@ -41,12 +42,12 @@ export function CanvasImageDownloadProgressDialog({
               {progress.phase === "saving" ? (
                 <Download className="h-4 w-4" />
               ) : (
-                <Loader2 className="h-4 w-4 animate-spin" />
+                <Loader2 className="h-4 w-4 motion-safe:animate-spin" />
               )}
             </span>
             <div>
               <div className="text-[14px] font-semibold">下载原图</div>
-              <div className="mt-0.5 text-[12px] text-white/58">{progress.message}</div>
+              <div className="mt-0.5 text-[12px] text-white/58" role="status">{progress.message}</div>
             </div>
           </div>
           {onCancel ? (
@@ -63,14 +64,19 @@ export function CanvasImageDownloadProgressDialog({
 
         <div className="mt-4">
           <div className="mb-2 flex items-center justify-between text-[12px] text-white/55">
-            <span>{loadedLabel && totalLabel ? `${loadedLabel} / ${totalLabel}` : "正在处理文件"}</span>
+            <span>{loadedLabel && totalLabel ? `${loadedLabel} / ${totalLabel}` : converting ? "格式转换中" : "正在处理文件"}</span>
             <span>{percent !== null ? `${percent}%` : "..."}</span>
           </div>
-          <div className="relative h-2 overflow-hidden rounded-full bg-white/10">
+          <div
+            className="relative h-2 overflow-hidden rounded-full bg-white/10"
+            role="progressbar"
+            aria-label={converting ? "图片格式转换" : "图片下载"}
+            aria-valuenow={percent ?? undefined}
+          >
             <div
               className={cn(
                 "absolute inset-y-0 left-0 rounded-full bg-gradient-to-r from-cyan-300 via-sky-400 to-emerald-300",
-                percent === null && "w-1/3 animate-[download-indeterminate_1.15s_ease-in-out_infinite]"
+                percent === null && "w-1/3 motion-safe:animate-[download-indeterminate_1.15s_ease-in-out_infinite]"
               )}
               style={percent !== null ? { width: `${percent}%` } : undefined}
             />

components/canvas/nodes/ImageNode.tsx

@@ -8236,7 +8236,6 @@ export function ImageNode({
     setDownloadProgress({
       phase: "preparing",
       message: "正在准备原图...",
-      percent: 5,
     });
 
     try {

lib/client/canvas-image-download.ts

@@ -1,8 +1,9 @@
 import { buildImageProxyUrl, getImageDownloadExtension } from "@/lib/image-delivery";
 import { inferOriginalImageUrl } from "@/lib/image-url";
 import { formatDownloadFailure, getDownloadFailure, type DownloadFailure } from "@/lib/canvas/download-error";
+import { withActivePageDownload } from "@/lib/client/page-refresh";
 
-export type CanvasImageDownloadPhase = "preparing" | "downloading" | "saving";
+export type CanvasImageDownloadPhase = "preparing" | "converting" | "downloading" | "saving";
 
 export type CanvasImageDownloadProgress = {
   phase: CanvasImageDownloadPhase;
@@ -192,7 +193,11 @@ function triggerCdnDownload(result: { downloadUrl: string; filename: string; byt
 const PHOTOSHOP_DOWNLOAD_EXTENSIONS = new Set(["jpg", "png", "gif", "bmp", "tiff"]);
 
 /** Preserve compatible originals and prepare a PNG for other stored images. */
-export async function downloadOriginalImage(params: DownloadCanvasImageParams): Promise<CanvasImageDownloadResult> {
+export function downloadOriginalImage(params: DownloadCanvasImageParams): Promise<CanvasImageDownloadResult> {
+  return withActivePageDownload(() => downloadOriginalImageFile(params));
+}
+
+async function downloadOriginalImageFile(params: DownloadCanvasImageParams): Promise<CanvasImageDownloadResult> {
   const { url, name, signal, onProgress } = params;
   const source = String(url || "").trim();
   if (!source) throw new Error("图片地址无效");
@@ -224,7 +229,7 @@ export async function downloadOriginalImage(params: DownloadCanvasImageParams):
       // The resolver names the attachment using the stored MIME type.
       const extension = delivery.filename.split(".").pop();
       if (!PHOTOSHOP_DOWNLOAD_EXTENSIONS.has(extension)) {
-        return downloadCanvasImageAsPng(params);
+        return downloadPngFile(params, "converting");
       }
       const result = triggerCdnDownload(delivery, signal);
       onProgress?.({ phase: "downloading", message: "已开始下载，可在浏览器下载列表查看进度" });
@@ -239,7 +244,7 @@ export async function downloadOriginalImage(params: DownloadCanvasImageParams):
   // A local blob can still be downloaded while its upload is in progress.
   if (/^https?:$/.test(target.protocol) && !PHOTOSHOP_DOWNLOAD_EXTENSIONS.has(extension)) {
     void response.body?.cancel().catch(() => {});
-    return downloadCanvasImageAsPng(params);
+    return downloadPngFile(params, "converting");
   }
   const blob = await readResponseBlobWithProgress(response, onProgress);
   signal?.throwIfAborted();
@@ -267,14 +272,15 @@ function toDownloadCandidates(url: string, candidates: string[] = []) {
 
 async function readResponseBlobWithProgress(
   response: Response,
-  onProgress?: (progress: CanvasImageDownloadProgress) => void
+  onProgress?: (progress: CanvasImageDownloadProgress) => void,
+  message = "正在下载原图..."
 ) {
   const totalBytes = Number(response.headers.get("content-length") || 0);
   if (!response.body) {
     const blob = await response.blob();
     onProgress?.({
       phase: "downloading",
-      message: "正在下载原图...",
+      message,
       loadedBytes: blob.size,
       totalBytes: totalBytes || blob.size,
       percent: 100,
@@ -294,7 +300,7 @@ async function readResponseBlobWithProgress(
     loadedBytes += value.byteLength;
     onProgress?.({
       phase: "downloading",
-      message: "正在下载原图...",
+      message,
       loadedBytes,
       totalBytes: totalBytes || undefined,
       percent: totalBytes > 0 ? Math.min(99, Math.round((loadedBytes / totalBytes) * 100)) : undefined,
@@ -306,13 +312,17 @@ async function readResponseBlobWithProgress(
   });
 }
 
-export async function downloadCanvasImageAsPng({
+export function downloadCanvasImageAsPng(params: DownloadCanvasImageParams): Promise<CanvasImageDownloadResult> {
+  return withActivePageDownload(() => downloadPngFile(params, "preparing"));
+}
+
+async function downloadPngFile({
   candidates,
   name,
   onProgress,
   signal,
   url,
-}: DownloadCanvasImageParams): Promise<CanvasImageDownloadResult> {
+}: DownloadCanvasImageParams, preparationPhase: "preparing" | "converting"): Promise<CanvasImageDownloadResult> {
   const raw = String(url || "").trim();
   if (!raw) {
     throw new Error("图片地址无效");
@@ -325,11 +335,9 @@ export async function downloadCanvasImageAsPng({
     "canvas-image"
   );
 
-  onProgress?.({
-    phase: "preparing",
-    message: "正在准备原图...",
-    percent: 8,
-  });
+  const isConverting = preparationPhase === "converting";
+  const conversionMessage = "正在转换为兼容 PNG，完成后自动下载";
+  onProgress?.({ phase: preparationPhase, message: isConverting ? conversionMessage : "正在准备原图..." });
 
   let response: Response | null = null;
   let errorPayload: DownloadErrorPayload | null = null;
@@ -368,7 +376,10 @@ export async function downloadCanvasImageAsPng({
       if (Date.now() >= preparationDeadline || preparationPolls >= 60) {
         throw new CanvasImageDownloadError("原图仍在准备中", { code: "preparation_timeout", status: 202, requestId: preparing.requestId });
       }
-      onProgress?.({ phase: "preparing", message: preparing.message || "正在准备原图，完成后将自动下载" });
+      onProgress?.({
+        phase: preparationPhase,
+        message: isConverting ? conversionMessage : preparing.message || "正在准备原图，完成后将自动下载",
+      });
       const delaySeconds = Math.max(preparationPolls > 5 ? 5 : 1, Math.min(5, Number(preparing.retryAfter) || 3));
       await waitForRetry(delaySeconds * 1000, signal);
       continue;
@@ -399,7 +410,6 @@ export async function downloadCanvasImageAsPng({
         retryAfterSeconds > 0
           ? `请求较多，${retryAfterSeconds} 秒后自动重试...`
           : "请求较多，正在自动重试...",
-      percent: 8,
     });
     await waitForRetry(retryAfterSeconds * 1000, signal);
   }
@@ -428,7 +438,9 @@ export async function downloadCanvasImageAsPng({
   const filename =
     parseAttachmentFilename(response.headers.get("content-disposition")) ||
     `${filenameBase}.png`;
-  const blob = await readResponseBlobWithProgress(response, onProgress);
+  const downloadMessage = isConverting ? "正在下载 PNG..." : "正在下载原图...";
+  onProgress?.({ phase: "downloading", message: downloadMessage });
+  const blob = await readResponseBlobWithProgress(response, onProgress, downloadMessage);
 
   onProgress?.({
     phase: "saving",

lib/client/page-refresh.ts

@@ -1,10 +1,44 @@
 export const BEFORE_PAGE_REFRESH = "app:before-page-refresh";
+export const PAGE_DOWNLOAD_ACTIVE_ATTRIBUTE = "data-page-download-active";
 export type PageRefreshRequest = {
   save: (action: () => Promise<void>) => void;
   block: (message: string) => void;
 };
 
+const downloadListeners = new Set<() => void>();
+let activePageDownloads = 0;
+
+export function isPageDownloadActive() {
+  return activePageDownloads > 0;
+}
+
+export function subscribeToPageDownloadActivity(listener: () => void) {
+  downloadListeners.add(listener);
+  return () => { downloadListeners.delete(listener); };
+}
+
+function publishDownloadActivity() {
+  if (typeof document !== "undefined") {
+    document.documentElement?.toggleAttribute(PAGE_DOWNLOAD_ACTIVE_ATTRIBUTE, isPageDownloadActive());
+  }
+  for (const listener of downloadListeners) listener();
+}
+
+export async function withActivePageDownload<T>(download: () => Promise<T>): Promise<T> {
+  if (++activePageDownloads === 1) publishDownloadActivity();
+  try {
+    return await download();
+  } finally {
+    if (--activePageDownloads === 0) publishDownloadActivity();
+  }
+}
+
+function assertPageDownloadFinished() {
+  if (isPageDownloadActive()) throw new Error("文件正在下载，请等下载完成后再刷新。");
+}
+
 export async function preparePageRefresh() {
+  assertPageDownloadFinished();
   const actions: Array<() => Promise<void>> = [];
   let blocked = "";
   window.dispatchEvent(new CustomEvent<PageRefreshRequest>(BEFORE_PAGE_REFRESH, {
@@ -12,4 +46,5 @@ export async function preparePageRefresh() {
   }));
   if (blocked) throw new Error(blocked);
   for (const action of actions) await action();
+  assertPageDownloadFinished();
 }

lib/jobs/image-archive-job.ts

@@ -26,14 +26,14 @@ function getBatchSize() {
   return Math.max(1, Math.min(50, Math.round(parsed)));
 }
 
-export async function runImageArchiveJob() {
+export async function runImageArchiveJob({ preferredTaskId }: { preferredTaskId?: string } = {}) {
   return trackRuntimeWork(async () => {
   const batchSize = getBatchSize();
   console.log(`[ImageArchiveJob] Start image archive job (batchSize=${batchSize})`);
 
   await recoverStaleImageArchiveTasks();
   scheduleImageDownloadPreparation();
-  const storeTasks = await getImageArchiveTasksToStore({ limit: batchSize });
+  const storeTasks = await getImageArchiveTasksToStore({ limit: batchSize, preferredTaskId });
   let storeSucceeded = 0;
   let storeFailed = 0;
 

lib/storage/image-archive-db.ts

@@ -98,8 +98,11 @@ export async function enqueueImageArchiveTasks(params: {
   return tasks;
 }
 
-export async function getImageArchiveTasksToStore(params: { limit: number }) {
+export async function getImageArchiveTasksToStore(params: { limit: number; preferredTaskId?: string }) {
   const now = new Date();
+  const priority = params.preferredTaskId
+    ? [asc(sql`case when ${imageArchiveTask.id} = ${params.preferredTaskId} then 0 else 1 end`)]
+    : [];
   return await db
     .select()
     .from(imageArchiveTask)
@@ -110,7 +113,7 @@ export async function getImageArchiveTasksToStore(params: { limit: number }) {
         lt(imageArchiveTask.attemptCount, MAX_IMAGE_ARCHIVE_ATTEMPTS),
       ),
     )
-    .orderBy(asc(imageArchiveTask.createdAt), asc(imageArchiveTask.id))
+    .orderBy(...priority, asc(imageArchiveTask.createdAt), asc(imageArchiveTask.id))
     .limit(Math.max(1, Math.min(50, params.limit)));
 }
 

lib/storage/image-archive-worker.ts

@@ -6,6 +6,7 @@ type Worker = {
   running: boolean;
   scheduled: boolean;
   requested: boolean;
+  preferredTaskId?: string;
   retryTimer?: ReturnType<typeof setTimeout>;
 };
 function getWorker(): Worker {
@@ -13,8 +14,9 @@ function getWorker(): Worker {
   return (root[workerKey] ??= { running: false, scheduled: false, requested: false });
 }
 
-export function scheduleImageArchiveWorker(deliveryConfirmed = false) {
+export function scheduleImageArchiveWorker(deliveryConfirmed = false, preferredTaskId?: string) {
   const worker = getWorker();
+  worker.preferredTaskId ??= preferredTaskId;
   worker.requested = true;
   if (worker.running || (worker.scheduled && !deliveryConfirmed)) return;
   worker.scheduled = true;
@@ -31,7 +33,9 @@ export function scheduleImageArchiveWorker(deliveryConfirmed = false) {
       const { runImageArchiveJob } = await import("@/lib/jobs/image-archive-job");
       do {
         worker.requested = false;
-        const result = await runImageArchiveJob();
+        const nextTaskId = worker.preferredTaskId;
+        worker.preferredTaskId = undefined;
+        const result = await runImageArchiveJob({ preferredTaskId: nextTaskId });
         retryNeeded = result.stats.pendingStore > 0 || result.stats.pendingReplace > 0 || result.pendingDownloads === true;
         // Stop when only backoff tasks remain; do not spin while storage is down.
         if (!worker.requested && result.store.total === 0 && result.replace.total === 0 && result.downloadTasks === 0) break;

lib/storage/original-image-download.ts

@@ -15,6 +15,10 @@ export async function resolveOriginalCdnDownload(source: string, name: string, s
   let target = new URL(source);
   if (target.origin !== base.origin && (!origin || target.origin !== new URL(origin).origin)) {
     const task = await findImageArchiveDownloadTask([...new Set([source, inferOriginalImageUrl(source)])]);
+    if (task?.status === "pending" && !task.targetUrl) {
+      const { scheduleImageArchiveWorker } = await import("./image-archive-worker");
+      scheduleImageArchiveWorker(false, task.id);
+    }
     target = new URL(task?.targetUrl || source);
   }
   if (origin && target.origin === new URL(origin).origin && !target.searchParams.has("token")) {

tests/routes/image-archive-flow.test.ts

@@ -242,7 +242,7 @@ test("inline outputs have short, stable preview identities and durable queue pay
 
 test("background storage starts after delivery and coalesces repeated wakeups", async () => {
   const callbacks: Array<() => Promise<void>> = [];
-  let runs = 0;
+  const preferences: Array<string | undefined> = [];
   const module = serverLoader({
     "next/server": {
       after: (fn: () => Promise<void>) => {
@@ -250,10 +250,10 @@ test("background storage starts after delivery and coalesces repeated wakeups",
       },
     },
     "@/lib/jobs/image-archive-job": {
-      runImageArchiveJob: async () => {
-        runs += 1;
+      runImageArchiveJob: async ({ preferredTaskId }: { preferredTaskId?: string }) => {
+        preferences.push(preferredTaskId);
         return {
-          store: { total: runs === 1 ? 1 : 0 },
+          store: { total: preferences.length === 1 ? 1 : 0 },
           replace: { total: 0 },
           stats: { pendingStore: 0, pendingReplace: 0 },
           downloadTasks: 0,
@@ -262,11 +262,11 @@ test("background storage starts after delivery and coalesces repeated wakeups",
     },
   })("lib/storage/image-archive-worker.ts");
   module.scheduleImageArchiveWorker();
-  module.scheduleImageArchiveWorker();
+  module.scheduleImageArchiveWorker(false, "requested-image");
   expect(callbacks).toHaveLength(1);
-  expect(runs).toBe(0);
+  expect(preferences).toEqual([]);
   await callbacks[0]();
-  expect(runs).toBe(2);
+  expect(preferences).toEqual(["requested-image", undefined]);
 });
 
 test("bucket failure retains the provider URL and retry task", async () => {

tests/routes/original-image-download.test.ts

@@ -1,5 +1,6 @@
 import { test, expect } from "@playwright/test";
 import { serverLoader } from "../helpers/canvas-download-server-loader";
+import type { CanvasImageDownloadProgress } from "@/lib/client/canvas-image-download";
 
 const config = { type: "qiniu-kodo", isEnabled: true, publicUrl: "https://cdn.example" };
 
@@ -53,6 +54,18 @@ test("temporary third-party URLs are never checked with HEAD when no archive is
   expect(await module.resolveOriginalCdnDownload("https://upstream.example/image.png", "image", new AbortController().signal)).toBeNull();
 });
 
+test("downloading a pending original prioritizes its existing archive task and keeps the proxy available", async () => {
+  const preferred: string[] = [];
+  const module = serverLoader({
+    "@/lib/db/queries": { getDefaultStorageConfig: async () => config },
+    "./image-archive-db": { findImageArchiveDownloadTask: async () => ({ id: "pending-image", status: "pending", targetUrl: null }) },
+    "./image-archive-worker": { scheduleImageArchiveWorker: (_delivery: boolean, id: string) => preferred.push(id) },
+    fetch() { throw new Error("The original must remain available through the proxy while it is queued"); },
+  })("lib/storage/original-image-download.ts");
+  expect(await module.resolveOriginalCdnDownload("https://upstream.example/queued.png", "image", new AbortController().signal)).toBeNull();
+  expect(preferred).toEqual(["pending-image"]);
+});
+
 test("a CDN metadata timeout falls back to the original Kodo object without reading its body", async () => {
   let closed = false;
   const module = serverLoader({
@@ -124,16 +137,18 @@ function browserMocks() {
 
 test("chat original downloads use a native CDN download without fetching the image through CORS", async () => {
   const dom = browserMocks(); const calls: string[] = [];
+  const progress: CanvasImageDownloadProgress[] = [];
   const client = serverLoader({ ...dom, fetch: async (url: string) => {
     calls.push(url);
     return Response.json({ delivery: "cdn", downloadUrl: "https://cdn.example/image.jpg?attname=original.jpg", filename: "original.jpg", bytes: 5000000 });
   } })("lib/client/canvas-image-download.ts");
-  const result = await client.downloadOriginalImage({ url: "https://cdn.example/image.jpg" });
+  const result = await client.downloadOriginalImage({ url: "https://cdn.example/image.jpg", onProgress: (event: CanvasImageDownloadProgress) => progress.push(event) });
   expect(result).toEqual({ filename: "original.jpg", bytes: 5000000 });
   expect(calls).toHaveLength(1);
   expect(new URL(calls[0], "https://app.example").searchParams.get("download")).toBe("resolve");
   expect(dom.frames[0].src).toBe("https://cdn.example/image.jpg?attname=original.jpg");
   expect(dom.links).toHaveLength(0);
+  expect(progress.map(event => event.phase)).toEqual(["preparing", "downloading"]);
 });
 
 test("original fallback preserves JPEG bytes and the MIME-derived filename", async () => {
@@ -149,6 +164,7 @@ test("original fallback preserves JPEG bytes and the MIME-derived filename", asy
 test("one click prepares a compatible PNG when the CDN original is WebP", async () => {
   const dom = browserMocks();
   const calls: string[] = [];
+  const progress: CanvasImageDownloadProgress[] = [];
   const url = "https://cdn.example/image.png";
   const client = serverLoader({ ...dom, fetch: async (path: string, init?: RequestInit) => {
     calls.push(path);
@@ -157,10 +173,19 @@ test("one click prepares a compatible PNG when the CDN original is WebP", async
     }
     expect(init?.method).toBe("POST");
     expect(JSON.parse(String(init?.body))).toMatchObject({ url, name: "商品", preparation: "async" });
+    if (calls.length === 2) {
+      return Response.json({ delivery: "preparing", retryAfter: 1, message: "正在准备原图" }, { status: 202 });
+    }
     return Response.json({ delivery: "cdn", downloadUrl: "https://cdn.example/prepared.png", filename: "商品.png", bytes: 900 });
   } })("lib/client/canvas-image-download.ts");
-  expect(await client.downloadOriginalImage({ url, name: "商品" })).toEqual({ filename: "商品.png", bytes: 900 });
-  expect(calls[1]).toBe("/api/canvas/download-image");
+  expect(await client.downloadOriginalImage({ url, name: "商品", onProgress: (event: CanvasImageDownloadProgress) => progress.push(event) }))
+    .toEqual({ filename: "商品.png", bytes: 900 });
+  expect(calls.slice(1)).toEqual(["/api/canvas/download-image", "/api/canvas/download-image"]);
+  expect(progress.map(event => event.phase)).toEqual(["preparing", "converting", "converting", "downloading"]);
+  for (const event of progress.filter(event => event.phase === "converting")) {
+    expect(event.message).toContain("正在转换为兼容 PNG");
+    expect(event.percent).toBeUndefined();
+  }
   expect(dom.frames.map(frame => frame.src)).toEqual(["https://cdn.example/prepared.png"]);
   expect(dom.links).toHaveLength(0);
 });
@@ -168,6 +193,7 @@ test("one click prepares a compatible PNG when the CDN original is WebP", async
 test("one click uses the PNG preparation route without buffering an incompatible proxy response", async () => {
   const dom = browserMocks();
   const calls: string[] = [];
+  const progress: CanvasImageDownloadProgress[] = [];
   let cancelled = false;
   const bytes = Uint8Array.of(137, 80, 78, 71, 13, 10, 26, 10);
   const client = serverLoader({ ...dom, fetch: async (path: string) => {
@@ -177,11 +203,16 @@ test("one click uses the PNG preparation route without buffering an incompatible
       return new Response(new ReadableStream({ cancel() { cancelled = true; } }),
         { headers: { "content-type": "image/avif" } });
     }
-    return new Response(bytes, { headers: { "content-type": "image/png" } });
+    return new Response(bytes, { headers: { "content-type": "image/png", "content-length": String(bytes.length) } });
   } })("lib/client/canvas-image-download.ts");
-  expect(await client.downloadOriginalImage({ url: "https://external.example/image", name: "商品" })).toEqual({ filename: "商品.png", bytes: bytes.length });
+  expect(await client.downloadOriginalImage({
+    url: "https://external.example/image", name: "商品", onProgress: (event: CanvasImageDownloadProgress) => progress.push(event),
+  })).toEqual({ filename: "商品.png", bytes: bytes.length });
   expect(cancelled).toBe(true);
   expect(calls[2]).toBe("/api/canvas/download-image");
+  expect(progress).toContainEqual({
+    phase: "downloading", message: "正在下载 PNG...", loadedBytes: bytes.length, totalBytes: bytes.length, percent: 99,
+  });
   expect(dom.links).toHaveLength(1);
   URL.revokeObjectURL(dom.links[0].href);
 });