Retry background removal result reads without recreating tasks

lib/ai/rmbg/service.ts

@@ -148,6 +148,18 @@ const withTimeout = async <T,>(
   }
 };
 
+async function readAosResult<T>(read: (signal: AbortSignal) => Promise<T>, timeoutMs: number): Promise<T> {
+  for (let attempt = 0; ; attempt++) {
+    try {
+      return await withTimeout(read, timeoutMs);
+    } catch (error) {
+      const name = error instanceof Error ? error.name : "";
+      if (attempt >= 2 || (name !== "TypeError" && name !== "AbortError")) throw error;
+      await sleep(1000 * (attempt + 1));
+    }
+  }
+}
+
 function getAosFriendlyErrorMessage(detail: string): string | null {
   const resolutionMatch = detail.match(/resolution excess,\s*width=(\d+),\s*height=(\d+)/i);
   if (resolutionMatch) {
@@ -449,17 +461,23 @@ async function processWithAosSegmentation(
       await sleep(1000);
       stage = "poll";
 
-      const pollResponse = await withTimeout(
+      const pollResponse = await readAosResult(
-        (signal) =>
+        async (signal) => {
-          fetch(taskUrl, {
+          const response = await fetch(taskUrl, {
             method: "GET",
             headers,
             signal,
-          }),
+          });
+          const payload = await response.json().catch((error) => {
+            if (error instanceof Error && error.name !== "SyntaxError") throw error;
+            return null;
+          });
+          return { ok: response.ok, status: response.status, statusText: response.statusText, payload };
+        },
         AOS_POLL_TIMEOUT_MS
       );
 
-      const pollPayload = await pollResponse.json().catch(() => null);
+      const pollPayload = pollResponse.payload;
       if (!pollResponse.ok || !pollPayload?.data) {
         logger.warn("aos_task_poll_failed", {
           hasPayload: pollPayload != null,
@@ -482,12 +500,14 @@ async function processWithAosSegmentation(
           taskId,
         });
         stage = "download";
-        const imageResponse = await withTimeout(
+        const imageResponse = await readAosResult(
-          (signal) =>
+          async (signal) => {
-            fetch(imageUrl, {
+            const response = await fetch(imageUrl, {
               method: "GET",
               signal,
-            }),
+            });
+            return { ok: response.ok, status: response.status, statusText: response.statusText, buffer: response.ok ? Buffer.from(await response.arrayBuffer()) : null };
+          },
           AOS_DOWNLOAD_TIMEOUT_MS
         );
 
@@ -502,7 +522,7 @@ async function processWithAosSegmentation(
           };
         }
 
-        const resultBuffer = Buffer.from(await imageResponse.arrayBuffer());
+        const resultBuffer = imageResponse.buffer!;
         return {
           success: true,
           imageBuffer: resultBuffer,
@@ -535,8 +555,13 @@ async function processWithAosSegmentation(
           : `AOS结果下载超时，任务已完成（任务 ${providerTaskId}）`;
       return { success: false, error: message };
     }
-    logger.warn("aos_provider_request_error", error);
+    logger.warn("aos_provider_request_error", error, { requestId: config.requestId, stage, taskId: providerTaskId });
-    return { success: false, error: error instanceof Error ? error.message : "未知错误" };
+    const detail = error instanceof Error ? error.message : "未知错误";
+    return { success: false, error: stage === "create"
+      ? `AOS创建任务连接失败，结果尚未确认：${detail}`
+      : stage === "poll"
+        ? `AOS查询任务连接失败，结果尚未确认（任务 ${providerTaskId}）：${detail}`
+        : `AOS结果下载连接失败，任务已完成（任务 ${providerTaskId}）：${detail}` };
   }
 }
 

lib/request-error.ts

@@ -234,9 +234,18 @@ export function getRequestFailureDetails(
   if (/AOS创建任务超时/.test(text)) {
     return detail("RMBG_CREATE_TIMEOUT", "抠图服务创建任务超时（120秒），结果尚未确认。", "请先查看原任务或联系管理员核对；不要连续点击，以免重复处理。", "unknown");
   }
+  if (/AOS创建任务连接失败/.test(text)) {
+    return detail("RMBG_CREATE_CONNECTION_FAILED", "抠图服务创建任务时连接中断，结果尚未确认。", "请先查看原任务或联系管理员核对；不要连续点击，以免重复处理。", "unknown");
+  }
+  if (/AOS查询任务连接失败/.test(text)) {
+    return detail("RMBG_POLL_CONNECTION_FAILED", "抠图服务查询任务时连接中断，原任务可能仍在处理。", "请保留当前页面并联系管理员核对原任务，避免重新提交。", "unknown");
+  }
   if (/AOS查询任务超时/.test(text)) {
     return detail("RMBG_POLL_TIMEOUT", "抠图服务查询任务超时，原任务可能仍在处理。", "请保留当前页面并联系管理员核对原任务，避免重新提交。", "unknown");
   }
+  if (/AOS结果下载连接失败/.test(text)) {
+    return detail("RMBG_RESULT_DOWNLOAD_CONNECTION_FAILED", "抠图已完成，但结果图片传输中断。", "请联系管理员按请求编号取回原任务结果，避免重复抠图。", "unknown");
+  }
   if (/AOS结果下载超时/.test(text)) {
     return detail("RMBG_RESULT_DOWNLOAD_TIMEOUT", "抠图已完成，但结果图片下载超时。", "请联系管理员按请求编号取回原任务结果，避免重复抠图。", "unknown");
   }

tests/routes/rmbg-delivery.test.ts

@@ -12,7 +12,7 @@ function rmbgLoader(fetch: typeof globalThis.fetch, timer?: typeof setTimeout) {
     "@/lib/db/schema": { generatedImage: {} },
     "@/lib/storage/service": { uploadFile: async (name: string) => ({ url: `${cdn}/${name}` }) },
     fetch,
-    setTimeout: timer || ((callback: () => void, ms: number) => setTimeout(callback, ms === 1000 ? 0 : ms)),
+    setTimeout: timer || ((callback: () => void, ms: number) => setTimeout(callback, ms <= 2000 ? 0 : ms)),
   }, { NEXT_PUBLIC_CANVAS_CDN_ORIGIN: cdn })("lib/ai/rmbg/service.ts");
 }
 
@@ -80,3 +80,40 @@ test("poll and result download timeouts retain their original task and distinct
   expect(download).toMatchObject({ code: "RMBG_RESULT_DOWNLOAD_TIMEOUT", outcome: "unknown" });
   expect(download.recommendation).toContain("取回原任务结果");
 });
+
+test("network and body interruptions retry only the original task reads", async () => {
+  const image = await sharp({ create: { width: 32, height: 32, channels: 4, background: "#abcdef00" } }).png().toBuffer();
+  let creates = 0, polls = 0, downloads = 0;
+  let networkError: Error;
+  const service = rmbgLoader(async (input, options) => {
+    if (options?.method === "POST") { creates++; return Response.json({ data: { task_id: "original-task" } }); }
+    if (String(input).endsWith("/original-task")) {
+      if (++polls === 1) throw networkError;
+      return Response.json({ data: { state: 1, image: "https://output.example/original.png" } });
+    }
+    if (++downloads === 1) return new Response(new ReadableStream({ start(controller) { controller.error(networkError); } }));
+    return new Response(image, { headers: { "content-type": "image/png" } });
+  });
+  networkError = new service.RmbgServiceError("fetch failed"); networkError.name = "TypeError";
+  const result = await service.executeRmbgJob({ userId: "test", imageBuffer: image, sourceImageUrl: `${cdn}/source.png`, skipGallerySave: true });
+  expect(result.original_url).toContain(cdn);
+  expect({ creates, polls, downloads }).toEqual({ creates: 1, polls: 2, downloads: 2 });
+});
+
+test("exhausted result reads preserve the completed task and never re-create it", async () => {
+  const image = await sharp({ create: { width: 16, height: 16, channels: 3, background: "white" } }).png().toBuffer();
+  let creates = 0, downloads = 0;
+  let networkError: Error;
+  const service = rmbgLoader(async (input, options) => {
+    if (options?.method === "POST") { creates++; return Response.json({ data: { task_id: "completed-task" } }); }
+    if (String(input).endsWith("/completed-task")) return Response.json({ data: { state: 1, image: "https://output.example/original.png" } });
+    downloads++; throw networkError;
+  });
+  networkError = new service.RmbgServiceError("fetch failed"); networkError.name = "TypeError";
+  let failure: Error | undefined;
+  try { await service.executeRmbgJob({ userId: "test", imageBuffer: image, sourceImageUrl: `${cdn}/source.png`, skipGallerySave: true }); }
+  catch (error) { failure = error as Error; }
+  expect({ creates, downloads }).toEqual({ creates: 1, downloads: 3 });
+  expect(failure?.message).toContain("completed-task");
+  expect(getRequestFailureDetails(failure)).toMatchObject({ code: "RMBG_RESULT_DOWNLOAD_CONNECTION_FAILED", outcome: "unknown" });
+});