lib/storage/original-image-download.ts

@@ -4,6 +4,7 @@ import { findImageArchiveDownloadTask } from "./image-archive-db";
 import { inferOriginalImageUrl } from "@/lib/image-url";
 import { getImageDownloadExtension } from "@/lib/image-delivery";
 import { sanitizeCanvasDownloadFileName } from "@/lib/canvas/photoshop-safe-download";
+import { HeadObjectCommand } from "@aws-sdk/client-s3";
 
 /** Resolve the archived original without waiting for a separate PNG conversion. */
 export async function resolveOriginalCdnDownload(source: string, name: string, signal: AbortSignal) {
@@ -28,8 +29,32 @@ export async function resolveOriginalCdnDownload(source: string, name: string, s
   // Only metadata crosses the application server. The browser receives the file
   // from the CDN, including when cross-origin fetch is disabled by storage CORS.
   const response = await fetch(target, {
-    method: "HEAD", cache: "no-store",
-    signal: AbortSignal.any([signal, AbortSignal.timeout(10_000)]),
+    method: "HEAD", cache: "default",
+    signal: AbortSignal.any([signal, AbortSignal.timeout(3_000)]),
+  }).catch(async (error) => {
+    signal.throwIfAborted();
+    if (target.search) throw error;
+    const { createS3Client, toDbS3UploadConfig } = await import("./service");
+    const storage = toDbS3UploadConfig(config);
+    if (!storage) throw error;
+    const key = decodeURIComponent(target.pathname.slice(base.pathname.replace(/\/$/, "").length + 1));
+    if (!key) throw error;
+    const client = createS3Client(storage);
+    try {
+      const object = await client.send(new HeadObjectCommand({ Bucket: storage.bucket, Key: key }), {
+        abortSignal: AbortSignal.any([signal, AbortSignal.timeout(5_000)]),
+      });
+      return new Response(null, { headers: {
+        "content-type": object.ContentType || "",
+        "content-length": String(object.ContentLength ?? 0),
+      } });
+    } catch (storageError) {
+      const status = (storageError as { $metadata?: { httpStatusCode?: number } })?.$metadata?.httpStatusCode;
+      if (status === 403 || status === 404) throw new Error(`HTTP ${status}`);
+      throw error;
+    } finally {
+      client.destroy();
+    }
   });
   if (!response.ok) throw new Error(`HTTP ${response.status}`);
   const contentType = response.headers.get("content-type") || "";

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

@@ -10,7 +10,8 @@ test("original downloads use the archived JPEG rather than the prepared PNG and
     "./image-archive-db": { findImageArchiveDownloadTask: async () => ({ targetUrl: "https://cdn.example/original.jpg", metadata: {
       downloadAsset: { status: "ready", url: "https://cdn.example/converted.png", contentType: "image/png" },
     } }) },
-    fetch: async (url: URL, options: { method: string }) => {
+    fetch: async (url: URL, options: { method: string; cache: string }) => {
+      expect(options.cache).toBe("default");
       calls.push({ url: url.toString(), method: options.method });
       return { ok: true, headers: new Headers({ "content-type": "image/jpeg", "content-length": "12345" }),
         arrayBuffer() { throw new Error("Image bytes must bypass the application"); } };
@@ -52,6 +53,28 @@ 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("a CDN metadata timeout falls back to the original Kodo object without reading its body", async () => {
+  let closed = false;
+  const module = serverLoader({
+    "@/lib/db/queries": { getDefaultStorageConfig: async () => config },
+    "./image-archive-db": {},
+    "./service": {
+      toDbS3UploadConfig: () => ({ bucket: "images" }),
+      createS3Client: () => ({
+        send: async (command: { input: { Bucket: string; Key: string } }) => {
+          expect(command.input).toEqual({ Bucket: "images", Key: "uploads/source.png" });
+          return { ContentType: "image/jpeg", ContentLength: 12345 };
+        },
+        destroy: () => { closed = true; },
+      }),
+    },
+    fetch: async () => { throw new DOMException("Timed out", "TimeoutError"); },
+  })("lib/storage/original-image-download.ts");
+  const result = await module.resolveOriginalCdnDownload("https://cdn.example/uploads/source.png", "图片.png", new AbortController().signal);
+  expect(result).toMatchObject({ delivery: "cdn", filename: "图片.jpg", bytes: 12345 });
+  expect(closed).toBe(true);
+});
+
 test("original download metadata reports missing sources with cause, advice and a feedback ID", async () => {
   const route = serverLoader({
     "next/server": { NextResponse: Response },